Sheet beam-type testing apparatus Number:7,417,236 from the United States Patent and Trademark Office (PTO) owispatent An electron beam apparatus such as a sheet beam based testing apparatus has an electron-optical system for irradiating an object under testing with a primary electron beam from an electron beam source, and projecting an image of a secondary electron beam emitted by the irradiation of the primary electron beam, and a detector for detecting the secondary electron beam image projected by the electron-optical system; specifically, the electron beam apparatus comprises beam generating means 2004 for irradiating an electron beam having a particular width, a primary electron-optical system 2001 for leading the beam to reach the surface of a substrate 2006 under testing, a secondary electron-optical system 2002 for trapping secondary electrons generated from the substrate 2006 and introducing them into an image processing system 2015, a stage 2003 for transportably holding the substrate 2006 with a continuous degree of freedom equal to at least one, a testing chamber for the substrate 2006, a substrate transport mechanism for transporting the substrate 2006 into and out of the testing chamber, an image processing analyzer 2015 for detecting defects on the substrate 2006, a vibration isolating mechanism for the testing chamber, a vacuum system for holding the testing chamber at a vacuum, and a control system 2017 for displaying or storing positions of defects on the substrate 2006.<H apparatus, testing, Sheet, beam, type, 7417236.html, Patent, pto, 7417236

Title: Sheet beam-type testing apparatus

Abstract: An electron beam apparatus such as a sheet beam based testing apparatus has an electron-optical system for irradiating an object under testing with a primary electron beam from an electron beam source, and projecting an image of a secondary electron beam emitted by the irradiation of the primary electron beam, and a detector for detecting the secondary electron beam image projected by the electron-optical system; specifically, the electron beam apparatus comprises beam generating means 2004 for irradiating an electron beam having a particular width, a primary electron-optical system 2001 for leading the beam to reach the surface of a substrate 2006 under testing, a secondary electron-optical system 2002 for trapping secondary electrons generated from the substrate 2006 and introducing them into an image processing system 2015, a stage 2003 for transportably holding the substrate 2006 with a continuous degree of freedom equal to at least one, a testing chamber for the substrate 2006, a substrate transport mechanism for transporting the substrate 2006 into and out of the testing chamber, an image processing analyzer 2015 for detecting defects on the substrate 2006, a vibration isolating mechanism for the testing chamber, a vacuum system for holding the testing chamber at a vacuum, and a control system 2017 for displaying or storing positions of defects on the substrate 2006.

Patent Number: 7,417,236 Issued on 08/26/2008 to Nakasuji, et al.

Inventors: Nakasuji; Mamoru (Kanagawa, JP), Noji; Nobuharu (Kanagawa, JP), Satake; Tohru (Kanagawa, JP), Kimba; Toshifumi (Kanagawa, JP), Sobukawa; Hirosi (Kanagawa, JP), Karimata; Tsutomu (Kanagawa, JP), Oowada; Shin (Kanagawa, JP), Yoshikawa; Shoji (Tokyo, JP), Saito; Mutsumi (Kanagawa, JP)
Assignee: Ebara Corporation (Tokyo, JP)

Appl. No.: 11/360,704

Filed: February 24, 2006

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
09891612	Jun., 2001	7049585

Foreign Application Priority Data


Jul 27, 2000 [JP]			2000-227132
Nov 02, 2000 [JP]			2000-335756
Dec 08, 2000 [JP]			2000-374164
Jan 31, 2001 [JP]			2001-22931
Feb 08, 2001 [JP]			2001-31901
Feb 08, 2001 [JP]			2001-31906
Feb 09, 2001 [JP]			2001-33599
Feb 13, 2001 [JP]			2001-36088
Mar 12, 2001 [JP]			2001-68301
Apr 13, 2001 [JP]			2001-115013
May 28, 2001 [JP]			2001-158662

Current U.S. Class: 250/440.11 ; 250/310; 250/492.2; 361/234

Current International Class: H01J 37/20 (20060101)

References Cited [Referenced By]

U.S. Patent Documents


2452893	November 1948	Bachman
3983401	September 1976	Livesay
4180738	December 1979	Smith et al.
4412133	October 1983	Eckes et al.
4584479	April 1986	Lamattina et al.
4607167	August 1986	Petric
4911103	March 1990	Davis et al.
4912052	March 1990	Miyoshi et al.
4944645	July 1990	Suzuki
5047646	September 1991	Hattori et al.
5359197	October 1994	Komatsu et al.
5362968	November 1994	Miyoshi et al.
5444256	August 1995	Nagai et al.
5576833	November 1996	Miyoshi et al.
5747819	May 1998	Nakasuji et al.
5751538	May 1998	Nakasuji
5763863	June 1998	Grosfeld et al.
5770863	June 1998	Nakasuji
5822171	October 1998	Shamouilian et al.
5892224	April 1999	Nakasuji
5981947	November 1999	Nakasuji et al.
5994704	November 1999	Nakasuji
6025600	February 2000	Archie et al.
6087667	July 2000	Nakasuji et al.
6125522	October 2000	Nakasuji
6265719	July 2001	Yamazaki et al.
6268606	July 2001	Abe et al.
6315512	November 2001	Tabrizi et al.
6344750	February 2002	Lo et al.
6476390	November 2002	Murakoshi et al.
6583634	June 2003	Nozoe et al.
6603130	August 2003	Bisschops et al.

Foreign Patent Documents


0999572	May., 2000	EP
52-115161	Sep., 1977	JP
52-117567	Oct., 1977	JP
57-072326	May., 1982	JP
57-125871	Aug., 1982	JP
60-000741	Jan., 1985	JP
62-100936	Oct., 1985	JP
61-239624	Oct., 1986	JP
62-195838	Aug., 1987	JP
63-6737	Jan., 1988	JP
1-95456	Apr., 1989	JP
03-022339	Jan., 1991	JP
03-053439	Mar., 1991	JP
03-102814	Apr., 1991	JP
03-266350	Nov., 1991	JP
03-276548	Dec., 1991	JP
04-266350	Sep., 1992	JP
05-047649	Feb., 1993	JP
05-063261	Mar., 1993	JP
05-251316	Sep., 1993	JP
07-065766	Mar., 1995	JP
07-249393	Sep., 1995	JP
08-138611	May., 1996	JP
9-73872	Mar., 1997	JP
09-073872	Mar., 1997	JP
09-311112	Dec., 1997	JP
10-062503	Mar., 1998	JP
10-073424	Mar., 1998	JP
10-125271	May., 1998	JP
10-177952	Jun., 1998	JP
10302697	Nov., 1998	JP
11-132975	May., 1999	JP
2000-3692	Jan., 2000	JP
2000-67798	Mar., 2000	JP
2000-067798	Mar., 2000	JP
2000-090868	Mar., 2000	JP
2000-100369	Apr., 2000	JP
2000-133565	May., 2000	JP
WO 9950651	Oct., 1999	WO
WO 00/25352	May., 2000	WO

Other References

Mamoru Nakasuji et al., Low Voltage and high speed operating electrostatic wafer chunk using sputtered tantalum oxide membrane, J. Vac. Sci. Technol. A 12(5), Sep./Oct. 1994, American Vacuum Society pp. 2834-2839. cited by other .
Mamoru Nakasuji et al., High-Emittance and Low-Brightness Electron Gun for Reducing-Image Projection system: Computer Simulation, Jpn. J. Appl. Phys. vol. 36 (1997) pp. 2404-2408. cited by other .
H. Hayashi, et al., LSI Testing Symposium 1998, Minutes of the meeting, P160 (1998) (partial translation). cited by other .
B. Lischke et al., Multi beam Concepts for Nanometer Devices, Japanese Journal of Applied Physics, vol. 28, No. 10, Oct. 1989, pp. 2058-2064. cited by other .
P. Sandland et al., A electron-beam inspecting system for x-ray mask production, J. Vac. Sci. Technol. B9 (b), Nov./Dec. 1991, American Vacuum Society, pp. 3005-3009. cited by other .
W.D. Meisburger, et al., Requirements and performance of an electron-beam column designed for x-ray mask inspection, J. Vac. Soc. Technol., B9 (6), Nov./Dec. 1991, American Vacuum Society, pp. 3010-3014. cited by other .
Table 5-1 work Finction in Metals p. 116. cited by other.

Primary Examiner: Berman; Jack I
Attorney, Agent or Firm: Westerman, Hattori, Daniels & Adrian, LLP.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATION

This application Continuation of U.S. application Ser. No. 09/891,612, filed Jun. 27, 2001, now U.S. Pat. No. 7,049,585.

Claims

What is claimed is:

1. A method of sucking and holding a wafer having at least one surface coated with an insulating film, comprising the steps of: providing the wafer on an electrostatic chuck; applying a voltage to at least one surface of the wafer through a contact having a knife edge shaped metal portion by braking the insulating film, the contact being operable to contact with a side surface of the wafer; and chucking the wafer by applying a voltage to the contact, a first voltage to a first electrode and a second voltage to a second electrode, respectively, the first electrode and the second electrode being disposed below an insulating layer on which the wafer is disposed.

2. The method according to claim 1, wherein the step of applying the first voltage and the step of applying the second voltage are performed in sequence.

3. The method according to claim 1, wherein the first electrode has a central portion.

4. The method according to claim 3, wherein the second electrode has a peripheral portion.

5. The method according to claim 1, wherein the first voltage and the second voltage gradually reduce so that gradually reduced voltage is applied to the first electrode and the second electrode.

6. A method of evaluating a wafer having at least one surface thereof coated with an insulating film, comprising the steps of: providing the wafer on an electrostatic chuck; applying a voltage to at least one surface of the wafer through a contact having a knife edge shaped metal portion by braking the insulating film, the contact being operable to contact with a side surface of the wafer; and chucking the wafer by applying a voltage to the contact, a first voltage to a first electrode and a second voltage to a second electrode, respectively, the first electrode and the second electrode being disposed below an insulating layer on which the wafer is disposed; emitting an electron beam to the wafer; detecting a secondary electron beam to capture an image on the wafer; evaluating the wafer based on the image on the wafer; and reducing the voltage across the wafer to zero and removing the wafer from the electrostatic chuck.

7. An electrostatic chuck for sucking and holding a wafer having at least one surface coated with an insulating film, comprising: a first electrode plate disposed below the wafer for holding the wafer and applying a first voltage to the wafer; a second electrode plate disposed below the wafer for holding the wafer and applying a second voltage to the wafer; an insulating layer disposed between the wafer and said first and second electrode plates; a contact having a knife edge shaped metal portion and operable to contact with a side surface of the wafer for breaking the insulating film to make a conduction to the wafer; and a power supply connected to the contact, the first electrode plate and the second electrode plate through a resistor.

8. The electrostatic chuck according to claim 7, wherein the first electrode plate has a central portion.

9. The electrostatic chuck according to claim 7, wherein the second electrode plate has a peripheral portion.

10. The electrostatic chuck according to claim 7, wherein the first voltage and the second voltage are applied to the first electrode plate and the second electrode plate, respectively.

11. The electrostatic chuck according to claim 10, wherein the first voltage and the second voltage gradually reduce so that gradually reduced voltages are applied to the first electrode plate and the second electrode plate.

12. An electron beam apparatus, comprising: an electron beam source for emitting an electron beam to a wafer; a detector for detecting a secondary electron beam to capture an image on the wafer; and a carrier unit for carrying and placing, on a stage device, a wafer having at least one surface coated with an insulating film, wherein the stage device comprises: a first electrode plate disposed below the wafer for holding and applying a first voltage to the wafer; a second electrode plate disposed below the wafer for holding the wafer and applying a second voltage to the wafer; an insulating layer disposed between the wafer and said first and second electrode plates; a contact having a knife edge shaped metal portion and operable to contact with the surface of the wafer for breaking the insulating film and making a conduction to the wafer; and a power supply connected to the contact, the first electrode plate and the second electrode plate.

13. The electron beam apparatus according to claim 12, wherein the first electrode plate has a central portion.

14. The electron beam apparatus according to claim 12, wherein said second electrode plate has a peripheral portion.

15. The electron beam apparatus according to claim 12, wherein the first voltage and the second voltage are applied to the first electrode plate and the second electrode plate.

16. The electron beam apparatus according to claim 12, wherein the first voltage and the second voltage gradually reduce so that gradually reduced voltages are applied to the first electrode plate and the second electrode plate.

17. A beam testing apparatus, comprising: a testing chamber having a stage for holding an object under test, wherein the stage has an electrostatic chuck for sucking the object; a beam generator for generating a rectangular or elliptic electron beam as a primary electron beam; an electro-optical system for guiding the primary electron beam in one direction and for guiding a secondary electron beam generated from the object in the opposite direction, the stage being movable relative to the electro-optical system; an image processing system for displaying or storing information of the object; and a transport mechanism for transporting the object into and out of the testing chamber and comprising a mini-environment chamber for supplying a clean gas to the object to prevent dust from attaching to the object and a sensor provided within the mini-environment chamber for observing the cleanliness of the mini-environment chamber, wherein the pressure in the mini-environment chamber being equal to atmosphere pressure; wherein the electrostatic chuck comprises: a first electrode plate disposed below the object for holding the object and applying a first voltage to the object; a second electrode plate disposed below the object for holding the object and applying a second voltage to the object; an insulatiua layer disposed between the wafer and said first and second electrode plates; a contact having knife edge shaped metal portion and operable to contact with a side surface of the object for breaking the insulating film and making a conduction to the object; and a power supply connected to the contact, the first electrode plate and the second electrode plate through a resistor.

18. The beam testing apparatus according to claim 17, wherein the first voltage and the second voltage gradually reduce so that gradually reduced voltages are applied to the first electrode plate and the second electrode plate.

Description

TECHNICAL FIELD

In semiconductor processes, design rules are now going to enter the era of 100 nm, and the production scheme is shifting from small-kind mass production represented by DRAM to a multi-kind small production such as SOC (silicon on chip). Associated with this shifting, the number of manufacturing steps has been increased, and an improved yield of each process is essential, so that testing for defects caused by the process becomes important. The present invention relates to a charged particle beam suitable for a sheet beam-type testing apparatus for testing a wafer after each of steps in a semiconductor process, and more particularly, to a sheet beam-type testing apparatus using a charged particle beam such as an electron beam, and a semiconductor device manufacturing method and an exposure method using the testing apparatus.

BACKGROUND ART

With the trend of increasingly higher integration of semiconductor devices and finer patterns, a need exists for high resolution, high throughput testing apparatuses. A resolution of 100 nm or less is required for examining defects on a wafer substrate of 100 nm design rule. Also, as the amount of testing is increased to cause an increase in manufacturing steps resulting from higher integration of devices, a higher throughput is required. Further, as devices are formed of an increased number of layers, testing apparatuses are required to have the ability to detect defective contacts (electric defect) of vias which connect wires between layers. While optical defect testing apparatuses are mainly used at present, it is anticipated that electron beam based defect testing apparatuses will substitute for optical defect testing apparatus as a dominant testing apparatus in the future from a viewpoint of the resolution and defective contact testing capabilities. However, the electron beam based defect testing apparatus also has a disadvantage in that it is inferior to the optical one in the throughput.

For this reason, a need exists for the development of a high resolution, high throughput testing apparatus which is capable of detecting electric defects. It is said that the resolution of an optical defect testing apparatus is limited to one half of the wavelength of used light, and the limit is approximately 0.2 .mu.m in an example of practically used optical defect detecting apparatus which uses visible light. On the other hand, in electron beam based systems, scanning electron microscopes (SEM) have been commercially available. The scanning electron microscope has a resolution of 0.1 .mu.m and takes a testing time of eight hours per 20 cm wafer. The electron beam based system also has a significant feature that it is capable of testing electric defects (broken wires, defective conduction, defective conduction of vias, and so on). However, it takes so long testing time that it is expected to develop a defect testing apparatus which can rapidly conduct a test.

Generally, a testing apparatus is expensive and low in throughput as compared with other process apparatuses, so that it is presently used after critical steps, such as after etching, deposition, CMP (chemical-mechanical polishing) planarization processing, and so on. Now, describing a testing apparatus in accordance with an electron beam based scanning (SEM) scheme, an SEM based testing apparatus narrows down an electron beam which is linearly irradiated to a sample for scanning. The diameter of the electron beam corresponds to the resolution. On the other hand, by moving a stage in a direction perpendicular to a direction in which the electron beam is scanned, a region under observation is tow-dimensionally irradiated with the electron beam. The width over which the electron beam is scanned generally extends over several hundred .mu.m. A secondary electron beam generated from the sample by the irradiation of the narrowed electron beam (called the "primary electron beam") is detected by a combination of a scintillator and a photomultiplier (photomultiplier tube) or a semiconductor based detector (using PIN diodes). The coordinates of irradiated positions and the amount of the secondary electron beam (signal strength) are combined to generate an image which is stored in a storage device or output on a CRT (Braun tube).

The foregoing is the principle of SEM (scanning electron microscope). From an image generated by this system, defects on a semiconductor (generally, Si) wafer is detected in the middle of a step. A scanning speed, corresponding to the throughput, is determined by the amount of primary electron beam (current value), diameter of the beam, and a response speed of a detector. Currently available maximum values are 0.1 .mu.m for the beam diameter (which may be regarded as the same as the resolution), 100 nA for the current value, and 100 MHz for the response speed of the detector, in which case it is said that a testing speed is approximately eight hours per wafer of 20 cm diameter.

In the SEM based testing apparatus described above, the cited testing speed is considered substantially as a limit. Therefore, a new scheme is required for increasing the testing speed, i.e., the throughput.

DISCLOSURE OF THE INVENTION

The present invention relates to an electron beam apparatus suitable for a sheet beam based testing apparatus, and a semiconductor device manufacturing method and an exposure method using the apparatus.

A first embodiment of the present invention provides a map projection type electron beam apparatus. For this purpose, the first embodiment provides a substrate testing apparatus, a substrate testing method and a device manufacturing method using such a substrate testing apparatus, characterized by comprising:

beam generating means for irradiating an electron beam having a particular width;

a primary electron-optical system for leading the charged particle beam to reach the surface of a substrate under testing;

a secondary electron-optical system for trapping a secondary electron beam generated from the substrate and leading the same to an image processing system;

a stage having for transportably holding the substrate with a continuous degree of freedom equal to at least one;

a testing chamber for the substrate;

a substrate transport mechanism for transporting the substrate into and out of the testing chamber;

an image processing analyzer for detecting defects on the substrate;

a vibration isolation mechanism for the testing chamber;

a vacuum system for holding the testing chamber at a vacuum; and

a control system for displaying or storing positions of defects on the substrate.

A second embodiment of the present invention provides an electron beam apparatus suitable for a testing apparatus for testing an object under testing by irradiating the object with an electron beam, and a device manufacturing method using the electron beam apparatus.

A second embodiment of the present invention provides a testing apparatus comprising:

an electron-optical device having an electron-optical system for irradiating the object under testing with a primary electron beam from an electron source to project an image of secondary electrons emitted by the irradiation of the primary electron beam, and a detector for detecting the secondary electron image projected by the electron-optical system;

a stage device for holding the object under testing and moving the object under testing relative to the electron-optical system;

a mini-environment device for supplying a clean gas to the object under testing to prevent dust from attaching to the object under testing;

a working chamber for accommodating the stage device, said working chamber being controllable in a vacuum atmosphere;

at least two loading chambers disposed between the mini-environment device and the working chamber, and adapted to be independently controllable in a vacuum atmosphere;

a loader having a carrier unit capable of transferring the object under testing between the mini-environment device and one of the loading chambers, and another carrier unit capable of transferring the object under testing between the one loading chamber and the stage device; and

a vibration isolator through which the working chamber and the loading chamber are supported.

Further, the second embodiment of the present invention provides a testing apparatus comprising:

an electron-optical device having an electron-optical system for irradiating the object under testing with a primary electron beam from an electron source, and for accelerating secondary electrons emitted by the irradiation of the primary electron beam with a deceleration electric field type objective lens to project an image of the secondary electrons, a detector for detecting the secondary electron image projected by the electron-optical system, and electrodes disposed between the deceleration electric field type objective lens and the object under testing for controlling a field intensity on the surface of the object under testing which is irradiated with the primary electron beam;

a stage device for holding the object under testing and moving the object under testing relative to the electron-optical system;

a working chamber for accommodating the stage device, said working chamber being controllable in a vacuum atmosphere;

a loader for supplying the object under testing onto the stage device within the working chamber;

a precharge unit for irradiating a charged particle beam to the object under testing placed in the working chamber to reduce variations in charge on the object under testing;

a potential applying mechanism for applying a potential to the object under testing; and

a supporting device supported through a vibration isolator for supporting the working chamber.

In the testing apparatus described above, the loader may include a first loading chamber and a second loading chamber capable of independently controlling an atmosphere therein, a first carrier unit for carrying the object under testing between the first loading chamber and the outside of the first loading chamber, and a second carrier unit disposed in the second loading chamber for carrying the object under testing between the first loading chamber and the stage device. The electron beam apparatus may further comprise a partitioned mini-environment space for supplying a clean gas flowing to the object under testing carried by the loader to prevent dust from attaching to the object under testing, wherein the supporting device may support the loading chamber and the working chamber through the vibration isolator.

Also, the testing apparatus may further comprise an alignment controller for observing the surface of the object under testing for an alignment of the object under testing with respect to the electron-optical system to control the alignment, and a laser interference range finder for detecting coordinates of the object under testing on the stage device, wherein the coordinates of the object under testing is determined by the alignment controller using patterns formed on the object under testing. In this event, the alignment of the object under testing may include rough alignment performed within the mini-environment space, and alignment in XY-directions and alignment in a rotating direction performed on the stage device.

Further, the second embodiment of the present invention provides a method of manufacturing a device comprising the step of detecting defects on a wafer using the foregoing testing apparatus in the middle of a process or subsequent to the process.

A third embodiment of the present invention provides an electron beam apparatus for focusing electron beams emitted from a plurality of electron beam sources on the surface of a sample through an electron-optical system, characterized by comprising:

a partition wall for separating the electron beam sources from the electron-optical system, wherein the partition wall has holes in a large aspect ratio for the electron beams to pass therethrough.

The holes are provided two or more for each of the electron beam sources. Each of the holes is formed at a position which swerves from the irradiating axis of the beam source. Preferably, the partition wall is formed of a material having a high rigidity, and the electron beam source and the electron-optical system are attached to the partition wall.

The third embodiment of the present invention also provides a device manufacturing method for evaluating a wafer in the middle of a process using the electron beam apparatus.

A fourth embodiment of the present invention provides an evaluation apparatus for directing an electron beam into a sample using an electrostatic optical system including an electrostatic lens, detecting a secondary electron beam generated from the sample by the irradiation of the electron beam to form data, and evaluating the sample based on the data, characterized in that:

electrodes in the electron-optical system are coated with a metal having a work function of 5 eV or higher.

According to this evaluation apparatus, since the electrodes or some of the electrodes are coated with a metal having a work function of 5 eV or higher, no secondary electron beam will be emitted from the electrodes, a discharge will be less likely to occur between electrodes, and a breakdown will occur between electrodes less frequently.

Preferably, the metal coated on the electrodes in the electrostatic optical system is platinum or an alloy which includes platinum as a main material. In this case, as the electrodes or some of the electrodes are coated with platinum (work function: 5.3 [eV]) or an alloy which includes platinum as a main material, a smaller amount of secondary electron beam will be emitted from the electrodes, so that a discharge will be less likely to occur between the electrodes, and a breakdown will occur between electrodes less frequently. Also, even with the sample being a semiconductor wafer, the platinum coated on the electrodes, if attached on a pattern of the semiconductor wafer, will not deteriorate transistors, so that it is suitable for testing a semiconductor wafer.

The fourth embodiment of the present invention provides an evaluation apparatus for directing an electron beam into a sample using an electrostatic optical system including an electrostatic lens, detecting a secondary electron beam generated from the sample by the irradiation of the electron beam to form data, and evaluating the sample based on the data, characterized in that:

the electrostatic lens includes at least two electrodes having potential differences, and insulating materials positioned between the two electrodes for holding the at least two electrodes;

at least one of the at least two electrodes has a first electrode surface having a minimum inter-electrode distance between the at least two electrodes, a second electrode surface having an inter-electrode distance longer than the first electrode surface, and a step between the first electrode surface and the second electrode surface in a direction along the at least two electrodes; and

the insulating material substantially vertically supports the second electrode surface and an electrode surface of the other electrode between the at least two electrodes, and a minimum creeping distance of the insulating material between the at least two electrodes is substantially equal to an inter-electrode distance in the supported electrode portion.

According to this evaluation apparatus, the electrodes are supported by the insulating material which has long creeping distance, so that a discharge between electrodes, and hence a breakdown between electrodes can be made less probable. Further, at least one of the electrodes is shaped to have the first electrode surface, the second electrode surface and the step between these electrode surfaces, so that the surface of the insulating material need not be formed with crimps, resulting in a lower manufacturing cost.

Also, since the minimum creeping distance of the insulating material between the electrodes is substantially equal to the distance between the electrodes in the supported electrode portion, the surface of the insulating material is substantially free from ruggedness between the electrodes, and a gas exhausted from the insulating material will not be increased. Therefor the degree of vacuum will not be lowered in a beam path of the apparatus.

Preferably, the metal coated on the electrodes in the electrostatic optical system is platinum or an alloy which includes platinum as a main material. In this case, as the electrodes or some of the electrodes are coated with platinum or an alloy which includes platinum as a main material, a discharge between electrodes, and hence a breakdown between electrodes will occur less frequently. Also, even with the sample being a semiconductor wafer, the platinum coated on the electrodes, if attached on a pattern of the semiconductor wafer, will not deteriorate transistors, so that it is suitable for testing a semiconductor wafer.

Further, the fourth embodiment of the present invention also provides a device manufacturing method using the evaluation apparatus, characterized by evaluating patterns on a semiconductor wafer, which is the sample, using the evaluation apparatus in the middle of device manufacturing.

According to this device manufacturing method, by using the evaluation apparatus in the middle of device manufacturing, even if patterns on the semiconductor wafer, which is a sample, are evaluated, the evaluation can be made without breakdown between electrodes in the electrostatic optical system.

A fifth embodiment of the present invention provides an electron beam apparatus for irradiating a sample with a primary electron beam using a primary optical system, and separating a secondary electron beam emitted from the sample from the primary optical system by an ExB separator for introduction into a secondary optical system, characterized in that:

the amount of deflection of the secondary electron beam by a magnetic field of the ExB separator is twice the amount of deflection by an electric field, and the direction of deflection by the magnetic field is opposite to the direction of deflection by the electric field.

This electron beam apparatus is characterized in that, in the electron beam apparatus for irradiating the sample with the primary electron beam using a primary optical system, and separating the secondary electron beam emitted from the sample from the primary optical system by the ExB separator for introduction into the secondary optical system, the amount of deflection of the secondary electron beam by the magnetic field of the ExB separator is twice the amount of deflection by an electric field, and the directions of deflection are opposite to each other.

The fifth embodiment of the present invention also provides an electron beam apparatus for irradiating a sample with a primary electron beam using a primary optical system, and separating a secondary electron beam emitted from the sample from the primary optical system by an ExB separator for introduction into a secondary optical system, characterized in that the amount of deflection of the primary electron beam by a magnetic field of the ExB separator is twice the amount of deflection by an electric field, and the direction of deflection by the magnetic field is opposite to the direction of deflection by the electric field.

This electron beam apparatus is characterized in that the amount of deflection of the first electron beam by the magnetic field of the ExB separator is twice the amount of deflection by the electric field, and the directions of deflection are opposite to each other in the electron beam apparatus for irradiating the sample with the primary electron beam using a primary optical system, and separating the secondary electron beam emitted from the sample from the primary optical system by the ExB separator for introduction into the secondary optical system.

In this event, preferably, the primary electron beam comprised of a plurality of beams is formed by the primary optical system for irradiating the surface of the sample, and secondary electron beams emitted from the samples by the irradiation of the primary electron beam comprised of the plurality of beams are detected by a plurality of secondary electron beam detectors.

The aforementioned electron beam apparatus can be available in any of a defect testing apparatus, a line width measuring apparatus, an alignment accuracy measuring apparatus, and a high time resolution potential contrast measuring apparatus.

Also, the fifth embodiment of the present invention provides a device manufacturing method for testing a wafer in the middle of a process using the electron beam apparatus.

A sixth embodiment of the present invention provides an electron beam apparatus, characterized by comprising:

a measuring mechanism for measuring first data indicative of rising of a secondary charged particle beam signal waveform when a pattern edge parallel in a first direction is moved in a second direction in regard to an excitation voltage of an objective lens, and second data indicative of rising of the secondary charged particle beam signal waveform when a pattern edge parallel in the second direction is moved in the first direction;

means for approximating each of the first data and the second data using quadratics, finding an excitation condition for the objective lens indicative of a minimum value of each quadratic; and

means for fitting the objective lens to an algebraic mean of the found excitation condition.

A plurality of the electron beam apparatuses may be positioned opposite to the sample such that respective ones of the plurality of primary electron beams are converged by corresponding ones of the objective lens simultaneously on different locations on the sample.

Further, preferably, the electron beam apparatus comprises means for correcting astigmatism after exciting the objective lens using the exciting means with a voltage equal to the algebraic average with the pattern being charged, and then evaluating the pattern.

Also, the sixth embodiment provides an electron beam apparatus for converging an electron beam using an electron-optical system including an objective lens, and scanning a pattern with the electron beam to evaluate the pattern, characterized in that:

the objective lens comprises a first electrode applied with a voltage close to a ground, and a second electrode applied with a voltage remote from the ground;

a focal distance of the objective lens can be changed by changing the voltage applied to the first electrode; and

the exciting means comprises means for changing the voltage applied to the second electrode to largely change the focal distance of the objective lens, and means for changing the voltage applied to the first electrode to change the focal distance of the objective lens in a short time.

The sixth embodiment of the present invention also provides a device manufacturing method for evaluating a wafer in the middle of a process using the electron beam apparatus.

A seventh embodiment of the present invention provides an electron beam apparatus for irradiating an object with an electron beam to perform at least one of working, manufacturing, observation and testing of the object, comprises:

a mechanical construction for determining a position of an electronic beam with respect to the object, a piezoelectric element attached to the mechanical construction for receiving a force from vibrations of the mechanical construction; and a vibration attenuating circuit electrically connected to the piezoelectric element to attenuate electric energy output from the piezoelectric element.

When an object is irradiated with an electron beam to perform at least one of working, manufacturing, observation and testing of the object, an external force including a vibration component at a resonant frequency of proper vibration applied to a mechanical construction causes the mechanical construction to amplify the vibration component at a resonant magnification determined by its transfer function, and to vibrate. This vibration applies a force to the piezoelectric element. The piezoelectric element transduces the vibration energy of the mechanical construction into electric energy which is output. However, since the vibration attenuating circuit attenuates this electric energy, the piezoelectric element generates a force to cancel the external force applied to the piezoelectric element. In this way, the vibrations generated by the mechanical resonance can be canceled to reduce the resonant magnification.

The mechanical construction is a portion or entirety of an electron beam applied apparatus which generates problematic vibrations, and an arbitrary mechanical construction for aligning the electron beam. For example, the mechanical construction may be optics in an optical system for focusing an electron beam on an object, a barrel for containing such an optical system, a supporting stand for carrying an object, or optics in an optical system for focusing a secondary electron beam generated by irradiating the object with the electron beam on a detector, a barrel for containing such an optical system, a barrel for containing the detector, and so on.

The vibration attenuating circuit comprises at least inductive means as an element having an inductance or an equivalent circuit of the element, and the inductive means is connected to the piezoelectric element having a static capacitance to form a resonant circuit. The inductance of the inductive means is determined with respect to the static capacitance of the piezoelectric element such that a resonant frequency of the resonant circuit substantially matches a resonant frequency of the mechanical construction.

Preferably, a resistive element is included in the vibration attenuating circuit. In this event, the capacitive impedance of the piezoelectric element and the inductive impedance of the inductive means cancel each other at the resonant frequency, so that the impedance of the resonant circuit virtually has only a resistive element. Therefore, during resonance, the electric energy output from the piezoelectric element is substantially fully consumed by the resistive element.

The seventh embodiment of the present invention also provides a semiconductor manufacturing method which comprises a step of executing at least one of working and manufacturing of semiconductor devices, and observation and testing of semiconductor devices during working or finished ones, using the electron beam apparatus.

According to an eighth embodiment of the present invention, an electrostatic chuck for electrostatically sucking and holding a wafer is applied with a voltage which increases or decreases between zero volt to a predetermined voltage over time. The electrostatic chuck is comprised of a laminate of a substrate, an electrode plate, and an insulating layer. A voltage associated with a voltage applied to a wafer is applied to the electrode plate to generate an attractive force between the wafer and the chuck. The electrode plate is divided into a first electrode comprised of a central portion thereof and some of a peripheral portion thereof, and a second electrode comprised of the remaining portion. The first electrode is first applied with a voltage, the wafer is then placed at a low potential or a ground potential, and subsequently the second electrode is applied with a voltage.

According to the eighth embodiment of the present invention, in a combination of a wafer and the electrostatic chuck for electrostatically sucking and holding the wafer, the electrostatic chuck is formed of the laminate of the substrate, electrode plate and insulating layer, the wafer is applied with a voltage through a predetermined resistor or a contact, and the contact is in the shape of a needle, the leading end of which comes in contact with the back surface of the wafer, or in the shape of a knife edge, the edge of which comes in contact with the side surface of the wafer.

The eighth embodiment of the present invention also provides a device manufacturing method for sucking and holding a wafer using the electrostatic chuck or the combination.

A ninth embodiment of the present invention provides an apparatus for carrying a sample on an XY stage, moving the sample to an arbitrary position in a vacuum, and irradiating the surface of the sample with an electron beam, characterized in that:

the XY stage comprises a non-contact supporting mechanism by means of static pressure bearings, and a vacuum sealing mechanism through differential pumping;

a partition is disposed between a location of the sample which is irradiated with the beam and a static pressure bearing support of the stage for reducing a conductance; and

a pressure difference is produced between an electron beam irradiating region and the static pressure bearing support.

According to the ninth embodiment, the non-contact supporting mechanism by means of the static pressure bearings is applied to a supporting mechanism for the XY stage for carrying a sample thereon, and the vacuum sealing mechanism through differential exhaust is provided around the static pressure bearings such that a high pressure gas used for the static pressure bearing does not leak into a vacuum chamber, so that the stage device can demonstrate highly accurate positioning performance in vacuum. Further, by forming the partition between the electron beam irradiated position and the static pressure bearing support for reducing the conductance, even if a gas adsorbed on the surface of a sliding part of the stage is released each time the sliding part of the stage is moved from a high pressure gas section to a vacuum environment, the exhausted gas hardly reaches the electron beam irradiated position, thereby preventing the pressure at the electron beam irradiated position from rising. In other words, the employment of the foregoing configuration can stabilize the degree of vacuum at the electron beam irradiated position on the surface of the sample, and highly accurately drive the stage, thereby making it possible to accurately process the sample with the electron beam without contaminating the surface of the sample.

The partition may contain a differential exhaust structure. In this event, the partition is placed between the static pressure bearing support and the electron beam irradiating region, and a vacuum evacuation path is routed within the partition to provide a differential pumping function, so that a gas released from the static pressure bearing support cannot pass through the partition into the electron beam irradiating region. In this way, the degree of vacuum at the electron beam irradiated position can be further stabilized.

The partition may have a cold trap function. In this event, in a region at a pressure of 10.sup.-7 Pa or higher, main components of a residual gas in the vacuum and a gas released from the surface of the material are water molecules. Therefore, if the water molecules can be efficiently exhausted, a high degree of vacuum can be readily maintained with stability. Therefore, a cold trap cooled at approximately -100.degree. C. to -200.degree. C., if provided in the partition, enables the released gas generated on the static pressure bearing side to be frozen and trapped by the cold trap, so that the released gas pass into the electron beam irradiating region with difficulty, and the degree of vacuum is readily maintained stable in the electron beam irradiating region. It goes without saying that the cold trap is effective not only for the water molecules but also for removing organic gas molecules such as a oil group which is a factor of hampering a clean vacuum.

Further, the partitions may be disposed at two locations, i.e., near the electron beam irradiated position and near the static pressure bearing. In this event, since the partitions which reduce the conductance are disposed at two locations, i.e., near the electron beam irradiated position and near the static pressure bearing, the vacuum chamber is divided into three chambers consisting of an electron beam irradiating chamber, a static pressure bearing chamber, and an intermediate chamber through small conductance. Then, a vacuum evacuation system is configured to set lower pressures from the charged particle beam irradiation chamber to the intermediate chamber and to the static pressure bearing chamber in this order. By doing so, even if the released gas causes a rise in pressure in the static pressure bearing chamber, a pressure fluctuating rate can be suppressed since this is a chamber in which the pressure has been initially set high. Therefore, fluctuations in pressure to the intermediate chamber are suppressed by the partition, thereby making it possible to reduce the fluctuations in pressure to a level at which substantially no problem arises.

The gas supplied to the static pressure bearings is preferably dry nitrogen or inert gas. Also preferably, at least surfaces of parts facing the static pressure bearings are applied with a surface treatment for reducing a released gas. As described above, on the sliding parts of the stage exposed to a high pressure gas atmosphere in the static pressure bering chamber, gas molecules included in the high pressure gas are adsorbed on their surfaces, and as the sliding parts are exposed to a vacuum environment, the adsorbed gas molecules are desorbed from the surfaces and act as a released gas which deteriorates the degree of vacuum. It is therefore necessary, for preventing the deterioration of the degree of vacuum, to reduce the amount of gas molecules to be adsorbed, and promptly exhaust adsorbed gas molecules.

For this purpose, it is effective that the static pressure bearings are supplied with a high pressure gas which is dry nitrogen, from which moisture has been sufficiently removed, or a highly pure inert gas (for example, a highly pure nitrogen gas) to remove gas components which are adsorbed to a surface with ease and desorbed therefrom with difficulty (organic substances, moisture and so on) from the high pressure gas. An inert gas such as nitrogen has a significantly low surface coverage to a surface and a significantly high desorbing speed from the surface, as compared with moisture and organic substance. Therefore, when a highly pure inert gas, from which moisture and organic components have been maximally removed, is used for the high pressure gas, a small amount of gas is released even when the sliding parts are moved from the static pressure bearing chamber to the vacuum environment. Also, since the released gas promptly attenuates, the deterioration of the degree of vacuum can be reduced. It is therefore possible to suppress a rise in pressure when the stage is moved.

Also effectively, at least surfaces of components, particularly, surfaces of parts which reciprocate between a high pressure gas atmosphere and a vacuum environment are applied with a surface treatment for reducing a released gas. As the surface treatment, when a base material is a metal, Tic (titanium carbide), TiN (titanium nitride), nickel plating, passivation, electrolytic polishing, composite electrolytic polishing, glass bead shot, and so on are contemplated. When a base material is Sic ceramics, coating of concise SiC layer by CVD and so on are contemplated. It is therefore possible to further suppress a rise in pressure when the stage is moved.

Also, the ninth embodiment of the present invention provides a wafer defect testing apparatus for testing the surface of a semiconductor wafer for defects using the electron beam apparatus. Since this can realize the testing apparatus which is highly accurate in stage positioning performance and stable in the degree of vacuum in the electron beam irradiating region, a testing apparatus which has high testing performance and is free from fear of contaminating the sample is provided.

In addition, the ninth embodiment of the present invention also provides an exposure apparatus for drawing a circuit pattern of a semiconductor device on the surface of a semiconductor wafer or a reticle using the electron beam apparatus. Since this can realize the exposure apparatus which is highly accurate in stage positioning performance and stable in the degree of vacuum in the electron beam irradiating region, an exposure apparatus which has high testing performance and is free from fear of contaminating the sample is provided.

Furthermore, the ninth embodiment of the present invention also provides a semiconductor manufacturing method for manufacturing semiconductors using the electron beam apparatus. Since this results in m