Determining method of thermal processing condition Number:6,787,377 from the United States Patent and Trademark Office (PTO) owispatent The invention is a method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups. The invention includes a first heat processing step of controlling respective substrate temperatures of a plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of respectively amending the provisional set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups. In the first heat processing step, the provisional set temperature profiles are profiles whose set temperatures change as time passes.<H Determining, processing, Determining, met, 6787377.html, Patent, pto, 6787377

Title: Determining method of thermal processing condition

Abstract: The invention is a method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups. The invention includes a first heat processing step of controlling respective substrate temperatures of a plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of respectively amending the provisional set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups. In the first heat processing step, the provisional set temperature profiles are profiles whose set temperatures change as time passes.

Patent Number: 6,787,377 Issued on 09/07/2004 to Wang, et al.

Inventors: Wang; Wenling (Tokyo-To, JP), Sakamoto; Koichi (Tokyo-To, JP), Suzuki; Fujio (Tokyo-To, JP), Yasuhara; Moyuru (Tokyo-To, JP)
Assignee: Tokyo Electron Limited (Tokyo-To, JP)

Appl. No.: 10/333,585

Filed: January 24, 2003

PCT Filed: July 23, 2001

PCT No.: PCT/JP01/06352

PCT Pub. No.: WO02/09164

PCT Pub. Date: January 31, 2002

Foreign Application Priority Data


Jul 25, 2000 [JP]			2000-224146
Jul 25, 2000 [JP]			2000-224147

Current U.S. Class: 438/14 ; 257/E21.293; 257/E21.324; 257/E21.525; 374/102; 374/137; 438/907; 438/909; 438/935

Field of Search: 438/14,907,909,935 374/102,137

References Cited [Referenced By]

U.S. Patent Documents


4309240	January 1982	Zaferes
4989970	February 1991	Campbell et al.

Foreign Patent Documents


5-291143	Nov., 1993	JP
6-318551	Nov., 1994	JP
11-186255	Jul., 1999	JP
2000-77347	Mar., 2000	JP
2000-195809	Jul., 2000	JP

Other References

International Preliminary Examination Report (PCT/IPEA/409) (translated) issued for PCT/JP01/06352. .
Notification of Transmittal of Copies of Translation of the International Preliminary Examination Report (PCT/IB/338) issued for PCT/JP01/06352..

Primary Examiner: Thompson; Craig A.
Assistant Examiner: Berezny; Nema
Attorney, Agent or Firm: Smith, Gambrell & Russell, LLP

Claims

What is claimed is:

1. A method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups, the method of determining a set temperature profile comprising; a first heat processing step of controlling respective substrate temperatures of a plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of respectively amending the provisional set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups; wherein, in the first heat processing step, the provisional set temperature profiles are profiles whose set temperatures change as time passes.

2. A method of determining a set temperature profile according to claim 1, wherein: in the first heat processing step, set temperatures of the provisional set temperature profiles have a substantially constant gradient with respect to time.

3. A method of determining a set temperature profile according to claim 1, wherein: in the first film-thickness measuring step, for at least one substrate in each of the plurality of groups, film thickness is measured at a plurality of points of each substrate, and an average of the measured values is obtained as a film thickness of the substrate.

4. A method of determining a set temperature profile according to claim 1, wherein; in the first set-temperature-profile amending step, averages of ideal set temperatures to be amended are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness, and the provisional set temperature profiles are amended based on the averages.

5. A method of determining a set temperature profile according to claim 1, further comprising after the first set-temperature-profile amending step; a second heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended first set temperature profiles for second-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a second film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a second set-temperature-profile amending step of respectively amending the first set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups.

6. A method of determining a set temperature profile according to claim 5, wherein: in the second set-temperature-profile amending step, averages of ideal set temperatures to be amended are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness, and the first set temperature profiles are amended based on the averages.

7. A method of determining a set temperature profile according to claim 6, wherein: in the second set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on averages in time of the provisional set temperature profiles during the first heat processing step, film thickness of the films on the first-batch substrates, averages in time of the first set temperature profiles during the second heat processing step, and film thickness of the films on the second-batch substrates.

8. A method of determining a set temperature profile according to claim 5, wherein: the second heat processing step, the second film-thickness measuring step and the second set-temperature-profile amending step are repeated at least twice in order thereof.

9. A method of determining a set temperature profile according to claim 5, wherein: the second heat processing step, the second film-thickness measuring step and the second set-temperature-profile amending step are repeated at least twice in order thereof.

10. A method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups, the method of determining a set temperature profile comprising; a first set-temperature-profile determining step of determining first set temperature profiles, each of which is set for each of a plurality of groups of substrates, in accordance with which films of substantially the same thickness between the plurality of groups are formed on the substrates when a process gas is introduced to conduct a heat process, and whose set temperatures don't change as time passes during the heat process, a second set-temperature-profile determining step of determining second set temperature profiles, each of which is set for each of the plurality of groups of the substrates by amending each first set temperature profile, in accordance with which a film of substantially the same thickness is formed on each of the substrates when a process gas is introduced to conduct a heat process, and whose set temperatures change as time passes during the heat process, and a third set-temperature-profile determining step of determining third set temperature profiles, each of which is set for each of the plurality of groups of the substrates by amending each second set temperature profile, in accordance with which films of substantially the same thickness between the plurality of groups are formed on the substrates when a process gas is introduced to conduct a heat process, and whose set temperatures change as time passes during the heat process.

11. A method of determining a set temperature profile according to claim 10, wherein: the first set-temperature-profile determining step includes: a first heat processing step of controlling respective substrate temperatures of the plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of calculating ideal constant set temperatures based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups, and of respectively amending the provisional set temperature profiles based on the ideal constant set temperatures.

12. A method of determining a set temperature profile according to claim 11, wherein; in the first set-temperature-profile amending step, the ideal constant set temperatures are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness.

13. A method of determining a set temperature profile according to claim 12, wherein: in the first film-thickness measuring step, for at least one substrate in each of the plurality of groups, film thickness is measured at a plurality of points of each substrate, and an average of the measured values is obtained as a film thickness of the substrate.

14. A method of determining a set temperature profile according to claim 11, wherein: the first set-temperature-profile determining step includes after the first set-temperature-profile amending step; a second heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended provisional set temperature profiles for second-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a second film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a second set-temperature-profile amending step of calculating again ideal constant set temperatures based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups, and of respectively amending again the amended provisional set temperature profiles based on the ideal constant set temperatures.

15. A method of determining a set temperature profile according to claim 14, wherein; in the second set-temperature-profile amending step, the ideal constant Bet temperatures are calculated again based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness.

16. A method of determining a set temperature profile according to claim 15, wherein: in the second set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on set temperatures of the provisional set temperature profiles during the first heat processing step, film thickness of the films on the first-batch substrates, set temperatures of the amended provisional set temperature profiles during the second heat processing step, and film thickness of the films on the second-batch substrates.

17. A method of determining a set temperature profile according to claim 11, wherein: the third set-temperature-profile determining step includes: a fifth heat processing step of controlling respective substrate temperatures of the plurality of groups in accordance with the respective second set temperature profiles for fifth-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a fifth film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a fifth set-temperature-profile amending step of calculating averages of set temperatures based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups, and of respectively amending the second set temperature profiles based on the averages of set temperatures.

18. A method of determining a set temperature profile according to claim 10, wherein: averages in time of set temperatures of the second set temperature profiles during the heat process are substantially the same as constant set temperatures of the first set temperature profiles during the heat process.

19. A method of determining a set temperature profile according to claim 10, wherein: set temperatures of the second set temperature profiles during the heat process have a substantially constant gradient with respect to time.

20. A method of determining a set temperature profile according to claim 10, wherein: the second set-temperature-profile determining step includes: a third heat processing step of controlling respective substrate temperatures of the plurality of groups in accordance with the respective first set temperature profiles for third-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a third film-thickness measuring step of measuring a thickness distribution of the films formed on the substrates; and a third set-temperature-profile amending step of respectively amending the first set temperature profiles based on the measured thickness distribution.

21. A method of determining a set temperature profile according to claim 20, wherein: the third film-thickness measuring step includes: a step of measuring a film thickness on the substrate near a central portion thereof, and a step of measuring a film thickness on the substrate near a plurality of peripheral portions thereof.

22. A method of determining a set temperature profile according to claim 20, wherein: the third film-thickness measuring step includes: a step of obtaining the thickness distribution on the substrates as a function of a distance from a substantially center thereof.

23. A method of determining a set temperature profile according to claim 22, wherein: the function is a function of a square of the distance from the substantially center thereof.

24. A method of determining a set temperature profile according to claim 20, wherein: the third film-thickness measuring step includes: a step of obtaining the thickness distribution on the substrates as a difference between a film thickness near a central portion thereof and a film thickness near a peripheral portion thereof.

25. A method of determining a set temperature profile according to claim 20, wherein: in the third set-temperature-profile amending step, a necessary temperature distribution in one substrate that is necessary for forming a film whose thickness is substantially uniform within a surface of the substrate is adapted to be calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness and the measured thickness distribution.

26. A method of determining a set temperature profile according to claim 25, wherein: the necessary temperature distribution is represented by a difference between a temperature of the substrate near a central portion thereof and a temperature of the substrate near a peripheral portion thereof.

27. A method of determining a set temperature profile according to claim 25, wherein: in the third set-temperature-profile amending step, necessary gradients with respect to time of set temperature profiles to be obtained by amended are calculated based on a dependant relationship between gradients with respect to time of set temperature profiles and temperature distribution within the substrate and the necessary temperature distribution, and the first set temperature profiles are adapted to be amended based on the necessary gradients.

28. A method of determining a set temperature profile according to claim 20, wherein: the second set-temperature-profile determining step includes after the third set-temperature-profile amending step; a fourth heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended first set temperature profiles for fourth-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a fourth film-thickness measuring step of measuring a thickness distribution of the films formed on the substrates; and a fourth set-temperature-profile amending step of respectively amending again the amended first set temperature profiles based on the measured thickness distribution.

29. A method of determining a set temperature profile according to claim 28, wherein: in the fourth set-temperature-profile amending step, a necessary temperature distribution in one substrate that is necessary for forming a film whose thickness is substantially uniform within a surface of the substrate is adapted to be calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness and the measured thickness distribution.

30. A method of determining a set temperature profile according to claim 29, wherein: in the fourth set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on averages in time of the first set temperature profiles during the third heat processing step, film thickness of the films on the third-batch substrates, averages in time of the amended first set temperature profiles during the fourth heat processing step, and film thickness of the films on the fourth-batch substrates.

31. A method of determining a set temperature profile according to claim 28, wherein: the fourth heat processing step, the fourth film-thickness measuring step and the fourth set-temperature-profile amending step are repeated at least twice in order thereof.

Description

TECHNICAL FIELD

The present invention relates to a determining method of a control condition for a thermal (heat) processing system that carries out a thermal process for an object to be processed such as a substrate. In particular, the present invention relates to a determining method of a control condition of a thermal processing system for forming a uniform film on a substrate.

BACKGROUND ART

For a semiconductor-device manufacturing process, as one of units that carry out a heat process to a semiconductor wafer (hereafter, a wafer) as a substrate, there is a vertical type of thermal processing unit that carries out a batch process. The unit holds many wafers in a tier-like manner with a wafer holder, which is called a wafer boat or the like, and transfers the holder into a vertical heat-processing furnace to conduct a CVD (Chemical Vapor Deposition) process or an oxidation process.

When a wafer undergoes a heat process by means of the thermal processing unit, ununiformity may arise in a condition of the heat process within a surface of the same wafer or between a plurality of wafers. As a result, unevenness in thickness distribution of a film formed by the heat process may be generated within a surface of the same processed wafer or between a plurality of processed wafers.

It is ideal that there is a uniform state in the thermal processing unit in order to uniformly conduct a heat process to a plurality of wafers. However, it is difficult to always make a state in the thermal processing unit uniform with respect to both time and space.

Therefore, it is necessary to precisely control the thermal processing unit in order to conduct a heat process to a plurality of wafers under a more uniform condition.

The present invention has been made to solve such a problem and it is an object of the present invention to provide a method of determining a control condition for uniformly conducting a heat process to a plurality of wafers by means of a thermal processing unit.

In addition, in a conventional heat processing unit, a stabilization time is required to make a temperature of a substrate stable, for a purpose of conducting a heat process uniformly within a surface of the substrate. Thus, it takes a long time to conduct the heat process by the stabilization time, so that the throughput is deteriorated.

The present invention has been made to solve such a problem and it is an object of the present invention to provide a heat processing unit that can carry out a heat process uniformly within a surface of a substrate even if the stabilization time is shortened.

DISCLOSURE OF THE INVENTION

The present invention is a method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups, the method of determining a set temperature profile comprising: a first heat processing step of controlling respective substrate temperatures of a plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of respectively amending the provisional set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups; wherein, in the first heat processing step, the provisional set temperature profiles are profiles whose set temperatures change as time passes.

Thickness distribution of the films between the substrates can be made uniform, by amending the provisional set temperature profiles that are profiles whose set temperatures change as time passes.

It is preferable to maintain substantially the same patterns except components of constant terms (offsets) when amending the provisional set temperature profiles. In the case, it becomes difficult for thickness distribution within a substrate to change between before and after the amendment.

Preferably, in the first heat processing step, set temperatures of the provisional set temperature profiles have a substantially constant gradient with respect to time. Steepness of the gradient is a factor that determines temperature distribution within a surface of the substrate. By making the gradient constant, temperature distribution during the heat process and hence distribution of film-forming rate can be made constant with respect to time.

Preferably, in the first film-thickness measuring step, for at least one substrate in each of the plurality of groups, film thickness is measured at a plurality of points of each substrate, and an average of the measured values is obtained as a film thickness of the substrate.

Preferably, in the first set-temperature-profile amending step, averages of ideal set temperatures to be amended are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness, and the provisional set temperature profiles are amended based on the averages.

Averages of the set temperatures are factors that correspond to averages of film-growing rates. Thus, it is effective to make film-thickness distribution uniform based on the averages of the set temperatures.

The thickness-temperature dependant relationship can be represented for example by a thickness-temperature coefficient. In addition, as a thickness-temperature dependant relationship, a theoretical equation can be used. Values obtained from experiments can be also used.

Preferably, the present invention is a method of determining a set temperature profile according to claim 1, further comprising after the first set-temperature-profile amending step: a second heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended first set temperature profiles for second-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a second film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a second set-temperature-profile amending step of respectively amending the first set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups.

Preferably, in the second set-temperature-profile amending step, averages of ideal set temperatures to be amended are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness, and the first set temperature profiles are amended based on the averages.

Preferably, in the second set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on: averages in time of the provisional set temperature profiles during the first heat processing step, film thickness of the films on the first-batch substrates, averages in time of the first set temperature profiles during the second heat processing step, and film thickness of the films on the second-batch substrates.

Preferably, the second heat processing step, the second film-thickness measuring step and the second set-temperature-profile amending step are repeated at least twice in order thereof.

In addition, the present invention is a method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups, the method of determining a set temperature profile comprising: a first set-temperature-profile determining step of determining first set temperature profiles, each of which is set for each of a plurality of groups of substrates, in accordance with which films of substantially the same thickness between the plurality of groups are formed on the substrates when a process gas is introduced to conduct a heat process, and whose set temperatures don't change as time passes during the heat process; a second set-temperature-profile determining step of determining second set temperature profiles, each of which is set for each of the plurality of groups of the substrates by amending each first set temperature profile, in accordance with which a film of substantially the same thickness is formed on each of the substrates when a process gas is introduced to conduct a heat process, and whose set temperatures change as time passes during the heat process; and a third set-temperature-profile determining step of determining third set temperature profiles, each of which is set for each of the plurality of groups of the substrates by amending each second set temperature profile, in accordance with which films of substantially the same thickness between the plurality of groups are formed on the substrates when a process gas is introduced to conduct a heat process, and whose set temperatures change as time passes during the heat process.

According to the invention, a control condition that can obtain good film-thickness distribution with respect to both between the plurality of groups of the substrates and within a surface of each of the substrates can be easily determined.

Preferably, the first set-temperature-profile determining step includes: a first heat processing step of controlling respective substrate temperatures of the plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of calculating ideal constant set temperatures based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups, and of respectively amending the provisional set temperature profiles based on the ideal constant set temperatures.

In the case, thickness distribution of the films on the substrates can be made uniform between the plurality of groups of the substrates.

Preferably, in the first set-temperature-profile amending step, the ideal constant set temperatures are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness.

As the thickness-temperature dependant relationship, a theoretical equation can be used, and also values obtained from experiments can be used.

Preferably, in the first film-thickness measuring step, for at least one substrate in each of the plurality of groups, film thickness is measured at a plurality of points of each substrate, and an average of the measured values is obtained as a film thickness of the substrate.

In addition, preferably, the first set-temperature-profile determining step includes after the first set-temperature-profile amending step: a second heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended provisional set temperature profiles for second-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a second film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a second set-temperature-profile amending step of calculating again ideal constant set temperatures based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups, and of respectively amending again the amended provisional set temperature profiles based on the ideal constant set temperatures.

Preferably, in the second set-temperature-profile amending step, the ideal constant set temperatures are calculated again based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness.

Preferably, in the second set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on: set temperatures of the provisional set temperature profiles during the first heat processing step, film thickness of the films on the first-batch substrates, set temperatures of the amended provisional set temperature profiles during the second heat processing step, and film thickness of the films on the second-batch substrates.

Preferably, the second heat processing step, the second film-thickness measuring step and the second set-temperature-profile amending step are repeated at least twice in order thereof.

Preferably, averages in time of set temperatures of the second set temperature profiles during the heat process are substantially the same as constant set temperatures of the first set temperature profiles during the heat process.

Preferably, set temperatures of the second set temperature profiles during the heat process have a substantially constant gradient with respect to time. Thus, temperature distribution on a surface of the substrate and hence distribution of film-growing rate can be made substantially constant with respect to time.

Preferably, the second set-temperature-profile determining step includes: a third heat processing step of controlling respective substrate temperatures of the plurality of groups in accordance with the respective first set temperature profiles for third-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a third film-thickness measuring step of measuring a thickness distribution of the films formed on the substrates; and a third set-temperature-profile amending step of respectively amending the first set temperature profiles based on the measured thickness distribution.

In the case, film-thickness distribution can be made uniform within a surface of each of the substrates, while maintaining uniformity in film-thickness distribution between the plurality of groups of the substrates to some extent.

Preferably, the third film-thickness measuring step includes: a step of measuring a film thickness on the substrate near a central portion thereof; and a step of measuring a film thickness on the substrate near a plurality of peripheral portions thereof.

Preferably, the third film-thickness measuring step includes: a step of obtaining the thickness distribution on the substrates as a function of a distance from a substantially center thereof.

Preferably, the function is a function of a square of the distance from the substantially center thereof.

Preferably, the third film-thickness measuring step includes: a step of obtaining the thickness distribution on the substrates as a difference between a film thickness near a central portion thereof and a film thickness near a peripheral portion thereof.

Preferably, in the third set-temperature-profile amending step, a necessary temperature distribution in one substrate that is necessary for forming a film whose thickness is substantially uniform within a surface of the substrate is adapted to be calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness and the measured thickness distribution.

Since temperature during the heat process is a factor greatly relating to film-growing rate, film-thickness distribution within a surface of each of the substrates can be made uniform, by controlling temperature distribution within the surface of each of the substrates.

As the thickness-temperature dependant relationship, a theoretical equation can be used, and also values obtained from experiments can be used. If averages in time of the set temperatures changing as time passes are used as the temperature, handling is easy.

Preferably, the necessary temperature distribution is represented by a difference between a temperature of the substrate near a central portion thereof and a temperature of the substrate near a peripheral portion thereof.

Preferably, in the third set-temperature-profile amending step, necessary gradients with respect to time of set temperature profiles to be obtained by amended are calculated based on a dependant relationship between gradients with respect to time of set temperature profiles and temperature distribution within the substrate and the necessary temperature distribution, and the first set temperature profiles are adapted to be amended based on the necessary gradients.

Thus, the temperature distribution within the surface of each of the substrates can be suitably controlled, so that the film-thickness distribution within the surface of each of the substrates can be made uniform.

In addition, preferably, the second set-temperature-profile determining step includes after the-third set-temperature-profile amending step: a fourth heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended first set temperature profiles for fourth-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a fourth film-thickness measuring step of measuring a thickness distribution of the films formed on the substrates; and a fourth set-temperature-pro file amending step of respectively amending again the amended first set temperature profiles based on the measured thickness distribution.

In the case, film-thickness distribution can be adjusted between the plurality of groups of the substrates, while maintaining uniformity in film-thickness distribution within a surface of each of the substrates to some extent.

Preferably, in the fourth set-temperature-profile amending step, a necessary temperature distribution in one substrate that is necessary for forming a film whose thickness is substantially uniform within a surface of the substrate is adapted to be calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness and the measured thickness distribution.

Preferably, in the fourth set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on: averages in time of the first set temperature profiles during the third heat processing step, film thickness of the films on the third-batch substrates, averages in time of the amended first set temperature profiles during the fourth heat processing step, and film thickness of the films on the fourth-batch substrates.

Preferably, the fourth heat processing step, the fourth film-thickness measuring step and the fourth set-temperature-profile amending step are repeated at least twice in order thereof.

Preferably, the third set-temperature-profile determining step includes: a fifth heat processing step of controlling respective substrate temperatures of the plurality of groups in accordance with the respective second set temperature profiles for fifth-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a fifth film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a fifth set-temperature-profile amending step of calculating averages of set temperatures based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups, and of respectively amending the second set temperature profiles based on the averages of set temperatures.

In addition, the present invention is a heat processing unit comprising: a processing chamber in which a substrate is contained; a heater that heats the substrate contained in the processing chamber; a gas-introducing part that introduces a process gas into the processing chamber in order to conduct a heat process to the substrate; and a controller that controls the heater and the gas-introducing part, in accordance with a process recipe including a set temperature profile defining a relationship between a passage of time and a set temperature, in order to conduct the heat process to the substrate, wherein: the set temperature profile is defined in such a manner that, with respect to the substrate during the heat process, both a central-high-temperature state wherein a temperature near a central portion thereof is higher than a temperature near a peripheral portion thereof and a peripheral-high-temperature state wherein a temperature near the peripheral portion thereof is higher than a temperature near the central portion thereof can appear.

According to the invention, during the heat process, there are both the central-high-temperature state wherein a temperature near the central portion of the substrate is higher and the peripheral-high-temperature state wherein a temperature near the peripheral portion thereof is higher. The central-high-temperature state and the peripheral-high-temperature state may cancel out each other, so that the central temperature and the peripheral temperature may approach each other in their averages with respect to time. Thus, even if a stabilization time is shortened, it is easy to uniformly conduct the heat process to a surface of the substrate.

Preferably, the set temperature profile is defined in such a manner that, with respect to the substrate during the heat process, an average in time of the temperature near the central portion thereof is substantially the same as an average in time of the temperature near the peripheral portion thereof. Since the average in time of the central temperature is substantially the same as the average in time of the peripheral temperature, it is easy to secure uniformity of the heat process to the surface of the substrate.

Preferably, the set temperature profile is defined to change as time passes during the heat process.

Preferably, the set temperature profile is defined to change as time passes before the heat process.

In addition, the present invention is a heat processing method of conducting a heat process to a substrate using a heat processing unit including: a processing chamber in which a substrate is contained; a heater that heats the substrate contained in the processing chamber; a gas-introducing part that introduces a process gas into the processing chamber in order to conduct a heat process to the substrate; and a controller that controls the heater and the gas-introducing part, in accordance with a process recipe including a set temperature profile defining a relationship between a passage of time and a set temperature, in order to conduct the heat process to the substrate; the method comprising: a heat processing step of heating the substrate and introducing the process gas into the processing chamber, in accordance with the process recipe, wherein: the heat processing step has: a central-high-temperature step wherein a temperature near a central portion of the substrate is higher than that near a peripheral portion thereof, and a peripheral-high-temperature step wherein a temperature near the peripheral portion of the substrate is higher than that near the central portion thereof.

According to the invention, the central-high-temperature state and the peripheral-high-temperature state may cancel out each other. Thus, even if a stabilization time is shortened, it is easy to secure uniformity of the heat process within a surface of the substrate.

The set temperature profile may be defined to change as time passes, during the heat processing step.

The set temperature profile may be defined to go down as time passes, during the heat processing step. In the case, preferably, the central-high-temperature step is conducted after the peripheral-high-temperature step. Because, if heating of the substrate and heat radiation from the substrate are conducted from the peripheral portion of the substrate, the peripheral temperature of the substrate goes down more rapidly than the central temperature, as the set temperatures go down as time passes.

Alternatively, the set temperature profile may be defined to go up as time passes, during the heat processing step. In the case, preferably, the peripheral-high-temperature step is conducted after the central-high-temperature step. Because, if heating of the substrate and heat radiation from the substrate are conducted from the peripheral portion of the substrate, the peripheral temperature of the substrate goes up more rapidly than the central temperature, as the set temperatures go up as time passes.

Preferably, an average in time of the temperature near the central portion of the substrate is substantially the same as an average in time of the temperature near the peripheral portion thereof, during the heat processing step. This can lead to securing of a uniform heat process within a surface of the substrate.

Preferably, the temperature near the peripheral portion of the substrate is an average of temperatures at a plurality of points near the peripheral portion of the substrate.

Preferably, the process gas is introduced into the processing chamber at a substantially constant density, during the heat processing step. In the case, it is easy to conduct a uniform heat process within a surface of the substrate.

Preferably, the process gas is introduced into the processing chamber under a substantially constant pressure, during the heat processing step. In the case, it is easy to conduct a uniform heat process within a surface of the substrate.

In addition, a heat processing method can further comprise a heating step whose set temperature profile is defined to go up as time passes, before the heat processing step.

In the case, a heat processing method can further comprise a change-in-time set temperature step whose set temperature profile is defined to change as time passes, between the heating step and the heat processing step. Alternatively, a heat processing method can further comprise a constant set temperature step whose set temperature profile is defined not to change as time passes, between the heating step and the heat processing step.

In addition, the present invention is a method of heat processing a substrate, comprising: a heating step of raising both a central temperature near a central portion of the substrate and a peripheral temperature near a peripheral portion of the substrate by heating the substrate by means of a thermal output within a first range; and a heat processing step of forming a film on the substrate while lowering both the central temperature and the peripheral temperature by heating the substrate from a periphery thereof in a process gas atmosphere by means of a thermal output within a second rage, which is smaller than the thermal output within the first range, the heat processing step having a central-high-temperature step wherein the central temperature of the substrate is higher than the peripheral temperature and a peripheral-high-temperature step wherein the peripheral temperature is higher than the central temperature.

According to the invention, even if a stabilization step between the heating step and the heat processing step (film-forming step) is shortened, or even if a stabilization step is not provided, it is easy to secure uniformity of the heat process within a surface of the substrate.

In addition, the present invention is a recording medium in which a process recipe is recorded, the process recipe including a set temperature profile defining a relationship between a passage of time and a set temperature during a heat process, wherein: a heat processing step wherein the substrate is heated and wherein a process gas is introduced into a processing chamber containing the substrate in accordance with the process recipe has: a central-high-temperature step wherein a temperature near a central portion of the substrate is higher than that near a peripheral portion thereof, and a peripheral-high-temperature step wherein a temperature near the peripheral portion of the substrate is higher than that near the central portion thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of an embodiment of a vertical thermal processing system according to the present invention;

FIG. 2 is a schematic perspective view of the embodiment of the vertical thermal processing system according to the present invention;

FIG. 3 is a block diagram showing detail of a controller included in the vertical thermal processing system in the embodiment shown in FIGS. 1 and 2;

FIG. 4 is a graph showing an example of a set temperature profile for the vertical thermal processing system in the embodiment shown in FIGS. 1 and 2;

FIG. 5 is a flow chart showing a control procedure to be carried out by the controller of the vertical thermal processing system in the embodiment shown in FIGS. 1 and 2;

FIG. 6 is a flow chart schematically showing a determining procedure of a set temperature profile in the embodiment shown in FIGS. 1 and 2;

FIG. 7 is a flow chart showing detail of a determining procedure of a first set temperature profile in the embodiment shown in FIGS. 1 and 2;

FIG. 8 is a view showing an example of measurement points for measuring a thickness of a film on a wafer;

FIG. 9 is a view showing an example of thickness distribution of the film on the wafer;

FIG. 10 are graphs showing examples of amended set temperature profiles and an example of a relationship between values of constant set temperature Tsp1 and positions of wafer.

FIG. 11 is a flow chart showing detail of a determining procedure of a second set temperature profile;

FIG. 12 are graphs showing an example of a relationship between film-thickness within a surface of the wafer and distances from the center of the wafer, and an example of temperature distribution within the surface of the wafer for making the film-thickness uniform within the surface of the wafer;

FIG. 13 are graphs showing an example of changes in time of a set temperature Tsp, a central temperature Tc, a peripheral temperature Te and a temperature difference within a surface .DELTA.T;

FIG. 14 is a graph showing a relationship between a change rate (gradient) of a set temperature and a temperature difference within a surface .DELTA.T;

FIG. 15 is a graph showing an amended first set temperature profile Tsp2 in comparison with a set temperature profile Tsp1 before amended;

FIG. 16 are graphs showing an example of changes in time of a set temperature, a central temperature Tc, a peripheral temperature Te and a temperature difference .DELTA.T, based on the amended first set temperature profile Tsp2;

FIG. 17 are graphs showing an example of changes in time of a set temperature, a central temperature Tc, a peripheral temperature Te and a temperature difference .DELTA.T, based on another amended first set temperature profile Tsp2;

FIG. 18 is a flow chart showing detail of a determining procedure of a third set temperature profile;

FIG. 19 is a graph showing an example of correspondence between amended second set temperature profiles and averages of change-in-time set temperatures during the deposition and positions of monitor wafers W1 to W5;

FIG. 20 is a schematic sectional view of an embodiment of a vertical thermal processing system according to the present invention;

FIG. 21 is a schematic perspective view of the embodiment of the vertical thermal processing system according to the present invention;

FIG. 22 is a block diagram showing detail of a controller included in the vertical thermal processing system in the embodiment shown in FIGS. 20 and 21;

FIG. 23 is a graph showing an example of a set temperature profile for the vertical thermal processing system in the embodiment shown in FIGS. 20 and 21;

FIG. 24 is a flow chart showing a control procedure for the vertical thermal processing system in the embodiment shown in FIGS. 20 and 21;

FIG. 25 are graphs showing changes in time of a wafer temperature, a temperature difference within a wafer surface and a heater output, in a case wherein the vertical thermal processing system is controlled in accordance with the set temperature profile in the embodiment shown in FIGS. 20 and 21;

FIG. 26 are graphs showing changes in time of a wafer temperature and a temperature difference within a wafer surface, in a case wherein the vertical thermal processing system is controlled in accordance with a set temperature profile as a comparison;

FIG. 27 is a graph showing a variation of a set temperature profile;

FIG. 28 is a graph showing a variation of a set temperature profile; and

FIG. 29 is a graph showing a variation of a set temperature profile.

BEST MODE FOR CARRYING OUT THE INVENTION

A vertical thermal processing system in a preferred embodiment according to the present invention will be described with reference to the accompanying drawings.

FIGS. 1 and 2 are a schematic sectional view and a schematic perspective view, respectively, of a vertical thermal processing system in a preferred embodiment according to the present invention.

As shown in FIG. 1, the vertical thermal processing system is provided with a double-wall reaction tube 2 including an inner tube 2a of, for example, quartz and an outer tube 2b of, for example, quartz. A tubular manifold 21 of a metal is connected to the lower end of the reaction tube 2.

The inner tube 2a has open upper and lower ends and is supported on projections projecting from the inner surface of the manifold 21. The outer tube 2b has a closed upper end and a lower end provided with a flange. The flange of the outer tube 2b is joined hermetically to the lower surface of a base plate 22 and the upper surface of the manifold 21.

As shown in FIG. 2, many semiconductor wafers W (substrates to be processed), for example 150 semiconductor wafers, are supported in a horizontal tier-like manner at vertical intervals on a wafer boat 23, i.e., a wafer holding device, in the reaction tube 2. The wafer boat 23 is held on a heat insulating tube (heat insulating member) 25 held on a cover 24.

Monitor wafers W1 to W5 are distributed on the wafer boat 23 to monitor process conditions.

The cover 24 is mounted on a boat elevator 26 for carrying the wafer boat 23 into and carrying the same out of the reaction tube 2. When raised to an upper limit position, the cover 24 closes the lower open end of the manifold 21, i.e., the open lower end of a processing vessel consisting of the reaction tube 2 and the manifold 21.

As shown in FIG. 1, a heater 3 provided with, for example, resistance-heating elements surrounds the reaction tube 2. The heater 3 is divided into five heating segments. That is, power controllers 41 to 45 control the respective heat generating rates of the heating segments 31 to 35 individually, respectively. The reaction tube 2, the manifold 21 and the heater 3 constitute a heating furnace.

Inner temperature sensors S1.sub.in to S5.sub.in, such as thermocouples, are disposed on the inner surface of the inner tube 2a at positions respectively corresponding to the heating segments 31 to 35. Outer temperature sensors S1.sub.out to S5.sub.out, such as thermocouples, are disposed on the outer surface of the outer tube 2b at positions respectively corresponding to the heating segments 31 to 35.

It can be thought that the inside of the inner tube 2a is divided into five zones (zones 1 to 5) correspondingly to the heating segments 31 to 35. Then, the wafers can be classified into five groups G1 to G5 correspondingly to respective locations where the wafers are arranged (zones 1 to 5). The whole groups G1 to G5 is called a batch. That is, all of the wafers arranged in the reaction tube 2 and placed on the wafer boat 23 form one batch to be thermally processed together at a time.

Each of the above monitor wafers W1 to W5 is arranged in each of the groups G1 to G5 (correspondingly to each of the zones 1 to 5). That is, the monitor wafers W1 to W5 are wafers (substrates) representing the groups G1 to G5, respectively, and correspond to the zones 1 to 5 in a one-to-one manner. Normally, the same wafers (semiconductor wafers) as the product wafers are used as the monitor wafers W1 to W5, and their temperatures become objects to be estimated. As described below, the temperatures of the monitor wafers W1 to W5 are estimated from measurement signals provided by the temperature sensors S1.sub.in to S5.sub.in and S1.sub.out to S5.sub.out.

As shown in FIG. 1, plural gas supply pipes are extended in the manifold 21 to supply gases into a space defined by the inner tube 2a. FIG. 1 shows only the two gas supply pipes 51 and 52. Flow controllers 61 and 62 for controlling the flow rate of gases, such as mass flow controllers, and valves (not shown) are placed in the gas supply pipes 51 and 52. A discharge pipe 27 is connected to the manifold 21 to exhaust a gas from the space between the inner tube 2a and the outer tube 2b. The discharge pipe 27 is connected to a vacuum pump, not shown. The discharge pipe 27 is provided with a pressure regulating unit 28 including, for example, a butterfly valve for regulating the pressure in the reaction tube 2 and/or a valve operating device.

The vertical thermal processing system includes a controller 100 for controlling process parameters including the temperature of a processing atmosphere created in the reaction tube 2 and the pressure in the reaction tube 2 and the flow rates of gases. Temperature measurement signals provided by the temperature sensors S1.sub.in to S5.sub.in and S1.sub.out to S5.sub.out are inputted to the controller 100. The controller 100 outputs control signals to the power controllers 41 to 45 for controlling power to be supplied to the heater 3, the pressure regulating unit 28 and the flow regulators 61 and 62.

FIG. 3 is a block diagram showing detail of a part relating to a control of the heater 3, included in the controller 100. As shown in FIG. 3, the controller 100 includes: a substrate temperature estimating unit 110 that outputs central temperatures T1c to T5c near respective central portions of the monitor wafers W1 to W5 and peripheral temperatures T1e to T5e near respective peripheral portions of the monitor wafers W1 to W5 which are estimated based on the measurement signals provided by the temperature sensors S1.sub.in to S5.sub.in and S1.sub.out to S5.sub.out ; a representative temperature calculating unit 120 that calculates respective representative temperatures T1r to T5r of the monitor wafers W1 to W5 from the central temperatures T1c to T5c and the peripheral temperatures T1e to T5e of the monitor wafers W1 to W5; and a heater output determining unit 140 that determines heater outputs h1 to h5 based on the representative temperatures T1r to T5r of the monitor wafers W1 to W5 and set temperature profiles stored in a set-temperature-profile storage unit 130. The heater outputs h1 to h5 determined by the heater output determining unit 140 are transferred to the power controllers 41 to 45 as control signals.

The set temperature profile represents a relationship between a passage of time and a set temperature (a temperature at which the wafer W should be). An example of the set temperature profile is shown in FIG. 4.

FIG. 4 is a graph showing the set temperature profile of the embodiment. As shown in FIG. 4, in the set temperature profile;

(A) From a time t0 to a time t1, the set temperature is maintained at T0. At that time, the wafer boat 20 holding the wafers W is transferred into the vertical heat-processing furnace 10 (loading step).

(B) From the time t1 to a time t2, the set temperature is raised from T0 to T1 at a constant rate (heating step).

(C) From the time t2 to a time t3, the set temperature is maintained at T1. With respect to actual temperatures of the wafers W, because of thermal inertia, it may take some time until the temperatures become constant after the set temperature has been made constant. Thus, until the wafer temperatures are stabilized, the subsequent step is waited (stabilizing