Title: Exposure apparatus and method of conveying mask and work
Abstract: An exposure apparatus includes a first transferring passage and a second transferring passage arranged at two different levels between a load/unload position and an exposure position, a first table and a second table one positioned in the load/unload position while the other positioned in the exposure position, a hoist mechanism which elevates one of the first and second tables to the first transferring passages, and lowers the other of the second and first tables to the second transferring passage, and a conveyor mechanism which transfers the first and second tables respectively to the load/unload position and the exposure position. Each of the first and second tables has a stage plate on which a work is placed, and a light-transmissible plate to which a mask is previously mounted.
Patent Number: 6,879,378 Issued on 04/12/2005 to Morita, et al.
| Inventors:
|
Morita; Akira (Tokyo, JP);
Nakazawa; Akira (Tokyo, JP)
|
| Assignee:
|
Orc Manufacturing Co., Ltd. (Tokyo, JP)
|
| Appl. No.:
|
617816 |
| Filed:
|
July 14, 2003 |
Foreign Application Priority Data
| Sep 10, 2002[JP] | 2002-264584 |
| Current U.S. Class: |
355/53; 355/72; 355/75; 355/77 |
| Intern'l Class: |
G03B 027//32; G03B 027//42; G03B 027//58; G03B 027//62 |
| Field of Search: |
355/53,72,75,77
|
References Cited [Referenced By]
U.S. Patent Documents
| 4541714 | Sep., 1985 | Miyamoto | 355/99.
|
| 4677303 | Jun., 1987 | Erdman | 250/559.
|
| 4996763 | Mar., 1991 | Sano et al. | 29/593.
|
| 5031334 | Jul., 1991 | Takamura | 33/621.
|
| 5222293 | Jun., 1993 | Ozimek et al. | 29/833.
|
| 5329126 | Jul., 1994 | Amemiya et al. | 250/453.
|
| 5390025 | Feb., 1995 | Morita et al. | 356/400.
|
| 5563682 | Oct., 1996 | Aikawa et al. | 355/53.
|
| Foreign Patent Documents |
| A-8-43950 | Feb., 1996 | JP.
| |
Primary Examiner: Fuller; Rodney
Attorney, Agent or Firm: Liniak, Berenato & White
Claims
What is claimed is:
1. An exposure apparatus comprising:
a first table and a second table each including a stage plate on which a
work is placed, and a light-transmissible plate to which a mask is
previously mounted, the first and second tables being transferred
alternately between a load/unload position where the work is
loaded/unloaded and aligned with the mask and an exposure position where
the aligned set of work and mask is exposed to light;
a first transferring passage and a second transferring passage arranged at
two different levels between the load/unload position and the exposure
position, wherein the first transferring passage transfers the first table
and the second table alternately, while the second transferring passage
transfers the second table and the first table alternately;
a hoist mechanism which elevates one of the first and second tables to the
first transferring passages, and lowers the other of the second and first
tables to the second transferring passage;
a conveyor mechanism which conveys the first and second tables elevated or
lowered by the hoist mechanism along the first and second transferring
passages, one from the load/unload position to the exposure position, and
the other from the exposure position to the load/unload position;
an alignment mechanism which aligns the work that is placed on one of the
tables conveyed to the load/unload position with the mask; and
a light-exposure mechanism which radiates light to the work placed on the
other of the tables conveyed to the exposure position.
2. An exposure apparatus according to claim 1, wherein said hoist mechanism
engages with the first and second tables, respectively, through hoist
guide means, and wherein said conveyor mechanism conveys the first and
second tables by drive means engageable with the hoist guide means.
3. An exposure apparatus according to claim 2, wherein said
light-transmissible plate includes a plate member which allows
transmission of light and to which the mask is set, a front plate-support
member provided at a front side of the plate member in relation to a
conveying direction of the table from the exposure position to the
load/unload position, a positioning protrusion extending from the front
plate-support member, and a rear plate-support member opposite to the
front plate-support member and fixed to the table so as to be engageable
with a rear side of the plate member.
4. An exposure apparatus according to claim 3, wherein an abutting member
is provided in the load/unload position to move toward and away from the
positioning protrusion of the light-transmissible plate, and wherein
light-transmissible plate guiding means is provided to push the rear
plate-support member of the light-transmissible plate so that the
positioning protrusion abuts against the abutting member.
5. An exposure apparatus according to claim 4, wherein each of said first
and second tables includes a frame member for remotely and oppositely
supporting the stage plate with respect to the light-transmissible plate,
and a suction mechanism for sucking a work against the mask.
6. An exposure apparatus according to claim 5, wherein said frame member
has guide means for retaining the stage plate at a predetermined position.
7. An exposure apparatus according to claim 5, wherein each of said first
and second tables includes a light-transmissible plate slide mechanism
which slidably engages with slide means provided on the frame member, so
that the stage plate is slidable against the light-transmissible plate.
8. An exposure apparatus according to claim 7, wherein each of said first
and second tables includes a stopper plate laterally extending with
respect to the second transfening passage extending from the exposure
position to the load/unload position, and wherein an abutment stop is
provided to move toward and away from a sliding locus of the stopper
plate.
9. An exposure apparatus according to claim 2, wherein each of said first
and second tables is provided with conveyor rollers at one of sides
extending along the first and second transferring passages, and an engage
portion engageable with the hoist guide means at the other side, wherein a
guide rail is arranged at both sides of the first and second transferring
passages so that the conveyor rollers move along the guide rail, and
wherein each guide rail of the first transferring passage includes a
cutout through which the conveyor rollers are elevated and lowered, and an
assist rail movable toward and away from the cutout.
10. An exposure apparatus according to claim 9, wherein said drive means is
arranged surrounding the load/unload position and the exposure position
and includes a drive belt engageable with the hoist guide means of the
first and second tables and conveying the first and second tables along
the first and second transferring passages, and belt guides for guiding
the drive belt.
11. An exposure apparatus according to claim 9, further comprising a first
hoist rod engageable with the first table through the hoist guide means at
the load/unload position and the exposure position, a second hoist rod
engageable with the second table through the hoist guide means at the
load/unload position and the exposure position, a first rotation center
rod connected to the first hoist rod through a first link member and being
a rotation fulcrum at the time of elevating or lowering the first hoist
rod through the first link member, a second rotation center rod connected
to the second hoist rod through a second link member and being a rotation
fulcrum at the time of lowering or elevating the second hoist rod through
the second link member, and link drive means for rotatably and
synchronously moving the first and second link members.
12. A method of conveying a mask and a work, in which a first table to
which a mask and a work are set is conveyed from a fist position to a
second position via a fist transferring passage, while a second table to
which a mask and a work are set is conveyed from the second position to
the first position via a second transferring passage, the method
comprising the steps of:
aligning the mask and the work on the first table at the first position,
while exposing the work on the second table to light through the mask at
the second position; and
conveying the first table and the second table in an endless manner along a
loop, which extends across the first and second positions and includes the
first and second transferring passages.
13. A method of conveying a mask and a work according to claim 12, wherein
the first position and the second position are parallel.
14. A method of conveying a mask and a work according to claim 12, wherein
the first transferring passage and the second transferring passage are
positioned vertically to each other.
15. A method of conveying a mask and a work according to claim 14, wherein
the first transferring passage is arranged on top of the second
transferring passage.
16. A method of conveying a mask and a work according to claim 12, wherein
the loop is rectangular.
17. A method of conveying a mask and a work according to claim 12, wherein
the first and second tables each includes a stage plate on which the work
is placed and a light-transmissible plate to which the mask is previously
mounted, and wherein the method further comprises the steps of placing the
work on the stage plate and mounting the mask to the light-transmissible
plate prior to the step of aligning the mask and the work on the first
table at the first position.
18. An exposure apparatus according to claim 1, wherein the hoist mechanism
elevates one of the first and second tables from the second transferring
passage to the first transferring passage, and lowers the other one of the
first and second tables from the first transferring passage to the second
transferring passage.
19. An exposure apparatus according to claim 18, wherein the first table
and the second table are transferred in an endless manner along a loop.
20. An exposure apparatus according to claim 18, wherein the first table
and the second table are transferred in a first direction along the first
transferring passage and in a second direction along the second
transferring passage, and wherein the first direction is opposite to the
second direction.
Description
FIELD OF THE INVENTION
The present invention relates to an exposure apparatus for use in exposure
of plate-like works, such as printed circuit boards, and a method of
conveying a mask and a work. The present invention particularly relates to
an exposure apparatus and an exposing method for alternately aligning and
exposing works in a load/unload position and an exposure position.
BACKGROUND OF THE INVENTION
In order to transfer images of a pattern of an electronic circuit onto a
work such as a printed circuit board, a liquid crystal panel and a color
filter for liquid crystal, a various exposure apparatus have been proposed
to expose a work to light by radiating ultraviolet light having a
predetermined wave length. Such exposure apparatus include so-called
semiautomatic exposure apparatus wherein a work is manually loaded and
unloaded by a worker and so-called automatic exposure apparatus wherein a
work is automatically operated from load to unload of the work.
One example of a semiautomatic exposure apparatus is disclosed in Japanese
Laid-open Patent Application No. 8-43950 (see columns [0043] to [0082])
and is explained with reference to FIG. 14. FIG. 14 is a schematic view of
a conventional semiautomatic exposure apparatus. As shown in FIG. 14, a
semiautomatic exposure apparatus 100 includes: a conveyor mechanism 103
which reciprocally conveys first and second tables 101, 102 for supporting
a work between a load/unload position H1 and an under exposure position
R1; a hoist mechanism 104 which elevates a support plate 101a (102a) of
one table 101 (102), on which a work W and a mask M are placed, to an
exposure position R2 after the table 101 (102) is carried by the conveyor
mechanism 103 from the load/unload position H1 to the under exposure
position R1, and lowers the other support plate 102a (101a), on which a
work W and a mask M are placed, positioned in the exposure position R2 to
the under exposure position R1 to place the support plate. 102a (101a)
onto the table 102 (101); an upper frame 105 which sucks and supports one
of the support plates 101a, 102a elevated by the hoist mechanism 104; a
light-exposure mechanism 107 which radiates light such as ultraviolet
light onto the upper frame 105 through an optical system 106; and imaging
means 108, an alignment table 109 and a mask-support mechanism 110
arranged in the load/unload position H1.
In operation of the semiautomatic exposure apparatus (hereinafter referred
to as an exposure apparatus) 100, the worker places a work W onto the
support plate 101a of the first table 101 that is positioned in the
load/unload position H1, and at the same time, the worker sets a mask M in
conformity with the work W. The imaging means 108 pictures the alignment
marks (not shown) of the mask M and the work W. When the work W is moved
for alignment, the mask-support mechanism 110 sucks the mask M and
displaces at least a part of the mask M for a certain distance from the
work W, during which the alignment table 109 moves the support plate 101a
for the purpose of alignment. The mask-support mechanism 110 is then
lowered to superpose the mask M on the work W. If the both alignment marks
(not shown) pictured by the imaging means 108 are within the allowable
range, the alignment operation of the mask M and the work W is completed.
The worker then fixes the mask M on the support plate 101a with the use of
fixing means such as adhesive tapes.
Next, the conveyor mechanism 103 is actuated, so that the first table 101
in the load/unload position H1 is carried toward the under exposure
position R1, while the second table 102 in the under exposure position R1
is carried toward the load/unload position H1. The hoist mechanism 104
elevates the support plate 101a of the first table 101 that is carried in
the under exposure position R1 so that the support plate 101a mates with
the upper frame 105 arranged in the exposure position R2 with the aid of
vacuum. The light-exposure mechanism 107 then radiates light through the
optical system 106 to the mask M and the work W that are sandwiched
between the upper frame 105 and the support plate 101a, so that the images
of the pattern of the mask M are transferred onto the work W.
After the exposure operation is completed, the vacuum seal between the
upper frame 105 and the support plate 101a is disengaged, and the work W
and the mask M are released from the upper frame 105. The work W and the
mask M are received by the hoist mechanism 104 in a manner to be placed
onto the support plate 101a, and are lowered to the first table 101
positioned in the under exposure position R2 by the lowering motion of the
hoist mechanism 104.
During the exposure operation, the alignment operation of a work W and a
mask M are carried out in the load/unload position H1 relative to the
second table 102 in a manner similar to the alignment operation on the
fist table 101.
Therefore, the alignment operation is carried out at one of the first and
second tables 101, 102 positioned in the load/unload position H1, while
the exposure operation is carried out in the exposure position R2 relative
to the other second and first tables 102, 101 positioned in the under
exposure position R1, so that the alignment operation and the exposure
operation are alternately and repeatedly carried out. It should be noted
that the first table 101 and the second table 102 are positioned in a
different height at the under exposure position R1. However, the support
plates 101a, 102a of the fist and second table 101, 102 can engage with
and disengage from the upper frame 105 by way of varying the stroke length
(hoist distance) of the hoist mechanism 104.
In another known exposure apparatus, the exposure operation is carried out
in the underexposure position R1 of the semiautomatic exposure apparatus
100. In this exposure apparatus, both tables are constructed such that a
light-transmissible plate which retains a mask is opened and closed to
allow a work to be set in a position facing to the mask. In this exposure
apparatus, a suitable exposure operation is carried out for a work on both
tables that are alternately transferred in a different height of the
underexposure position, by way of varying the exposure time relative to
the respective tables.
However, the conventional exposure apparatus have the following drawbacks.
(1) Since the support plate to be alternately transferred by the first and
second tables and separated from the tables is elevated through the hoist
mechanism so as to set a work in the exposure position with the work
mating with the upper frame, it is difficult to retain the alignment
position between the work and the mask until they are set in the exposure
position. Further, since both tables are carried at different height
levels in the load/unload position, the alignment operation has to be
carried out at different height levels. This requires a further
operational control when compared with the alignment operation carried out
on the alignment table at the same height.
(2) Since a metal frame is provided in a manner surrounding the
light-transmissible plate that is adjacent to the mask, a setting
operation of the light-transmissible plate is required whenever the
light-transmissible plate is replaced or initially set up.
(3) During the alignment operation of the mask and the work, the work is
moved for alignment while the mask is retained by the mask-support
mechanism 110. However, this requires a complicated structure. Further,
the worker fixes the mask and the work by means of adhesive tapes, leading
to increased number of operations of the worker.
(4) At the time of alignment of the mask with the work, the worker has to
set both the mask and the work, which makes the load/unload operation
complicated. In the exposure apparatus of the type in which the
light-transmissible plate can be open and closed for the placement of a
work, the open/close motion of the light-transmissible plate requires a
great effort for the worker, and further, the imaging means has to be
retracted so as not to bump against the light-transmissible plate during
the open/close motion of the light-transmissible plate.
(5) The conventional exposure apparatus includes a mechanism which
alternately carries both tables between the load/unload position and the
exposure position through the two transferring passages arranged one on
top of the other, and a mechanism which separates the tables from the
conveyor mechanism to carry out the alignment operation and the exposure
operation at the load/unload position and the exposure position,
respectively. Therefore, the conventional exposure apparatus requires the
control of the vertical movement of the support plate as well as a large
driving force to move the support plate.
In view of the above, the present invention seeks to provide an exposure
apparatus and an exposing method wherein the alignment position and the
exposure position of the works are substantially the same in height
direction, and wherein the metal frame surrounding the light-transmissible
plate can be omitted, and wherein the operation of the light-transmissible
plate where a mask is set is readily performed.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided an exposure
apparatus comprising:
a first table and a second table each including a stage plate on which a
work is placed, and a light-transmissible plate to which a mask is
previously mounted, the first and second tables being transferred
alternately between a load/unload position where the work is
loaded/unloaded and aligned with the mask and an-exposure position where
the aligned set of work and mask is exposed to light;
a first transferring passage and a second transferring passage arranged at
two different levels between the load/unload position and the exposure
position, wherein the first transferring passage transfers the first table
and the second table alternately, while the second transferring passage
transfers the second table and the first table alternately;
a hoist mechanism which elevates one of the first and second tables to the
first transferring passages, and lowers the other of the second and first
tables to the second transferring passage;
a conveyor mechanism which conveys the first and second tables elevated or
lowered by the hoist mechanism along the first and second transferring
passages, one from the load/unload position to the exposure position, and
the other from the exposure position to the load/unload position;
an alignment mechanism which aligns the work that is placed on one of the
tables conveyed to the load/unload position with the mask; and
a light-exposure mechanism which radiates light to the work placed on the
other of the tables conveyed to the exposure position.
With this construction of the exposure apparatus, after completing the
exposure operation and the alignment operation of the first and second
tables, in the case where the first transferring passage is positioned
upward of the second transferring passage, the first table is elevated to
the first transferring passage by the hoist mechanism and the second table
is lowered to the second transferring passage by the hoist mechanism. The
first table and the second table each supporting the mask and the work are
alternately transferred to the load/unload position and the exposure
position through the conveyor mechanism. One of the load/unload position
and the exposure position may be arranged on the first transferring
passage or on the second transferring passage, and the other may be
arranged on the second transferring passage or on the first transferring
passage. Further, because the mask is set to the light-transmissible plate
of each table, the alignment mechanism directly pictures the alignment
marks of the mask and the work.
In the aforementioned exposure apparatus, the hoist mechanism engages with
the first and second tables, respectively, through hoist guide means, and
the conveyor mechanism conveys the first and second tables by drive means
which is engageable with the hoist guide means.
With this construction of the exposure apparatus, a work is placed on the
stage plate of the first table at the load/unload position, and by the
alignment mechanism the work is aligned with the mask that is set on the
light-transmissible plate. When doing so, by the light-exposure mechanism
the exposure operation is applied to the second table that has been
transferred to the exposure position after completing the alignment
operation. After the alignment operation of the first table and the
exposure operation of the second table are completed, the first table is
elevated to the first transferring passage by the hoist mechanism and
through the hoist guide means and the second table is lowered to the
second transferring passage by the hoist mechanism and through the hoist
guide means. Thereafter, the first and second tables are transferred along
the respective transferring passages with the hoist guide means being
transferred by the drive means of the conveyor mechanism, so that the
first table is transferred to the exposure position and the second table
is transferred to the load/unload position.
According to a second aspect of the invention, there is provided a method
of conveying a mask and a work, in which a first table to which a mask and
a work are set is conveyed from a fist position to a second position via a
fist transferring passage, while a second table to which a mask and a work
are set is conveyed from the second position to the first position via a
second transferring passage, the method comprising the steps of:
aligning the mask and the work on the first table at the first position,
while exposing the work on the second table to light through the mask at
the second position; and
conveying the first table and the second table in an endless manner along a
loop, which extends across the first and second positions and includes the
first and second transferring passages.
With this method, the first table and the second table are conveyed along
the loop in an endless manner. This achieves effective utilization of the
limited inner space of the exposure apparatus as well as provides a
smaller-sized exposure apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention will be described below, by
way of example only, with reference to the accompanying drawings, in
which:
FIG. 1 is an exploded perspective view of an exposure apparatus according
to the present invention, schematically illustrating the whole arrangement
of the exposure apparatus;
FIG. 2 is a perspective view illustrating a structure of a first table
(second table) of the exposure apparatus;
FIG. 3 is a perspective view illustrating an abutting reference position in
a load/unload position of the exposure apparatus;
FIG. 4 is a schematic view showing a structure of an alignment table of the
exposure apparatus;
FIG. 5 is a perspective view illustrating a structure of the alignment
table in the load/unload position of the exposure apparatus;
FIG. 6 is a schematic view illustrating the whole arrangement of the
exposure apparatus;
FIG. 7 is a plan view illustrating structures of two transferring passages
of the exposure apparatus;
FIGS. 8A through 8E are schematic views explaining an alignment operation
of the exposure apparatus;
FIGS. 9A-1 through 9D-2 are schematic views explaining a hoisting operation
and a conveying operation of the exposure apparatus;
FIGS. 10A through 10F are schematic views illustrating the hoisting
operation and the conveying operation of the exposure apparatus;
FIGS. 11A and 11B are schematic views showing two tables of the exposure
apparatus respectively arranged in the transferring passages;
FIGS. 12A-1 through 12D-2 are schematic views illustrating structures of a
light-transmissible plate and a stage plate of the tables in the
transferring passages;
FIGS. 13A through 13G are schematic views illustrating the whole operations
of the tables of the exposure apparatus; and
FIG. 14 is a schematic view illustrating the whole arrangement of a
conventional exposure apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the accompanying drawings, one preferred embodiment of
the present invention will be described. Herein, as one example of the
present invention, an exposure apparatus is of the type exposing one side
of a substrate.
As shown in FIGS. 1, 2 and 6, an exposure apparatus 1 provides a
load/unload position P1 as a first position where a worker loads or
unloads a work W in front of a housing 2 and an exposure position P2 as a
second position where a work W is exposed to light at the back of the
housing 2.
The exposure apparatus 1 includes: a first transferring passage L1 and a
second transferring passage L2 arranged at two different levels between
the load/unload position P1 and the exposure position P2 such that the
first and second transferring passages L1, L2 form a part of a loop
passing through the first position P1 and the second position P2; a first
table 10 and a second table 20 respectively transferred along the first
and second transferring passages L1, L2 in an endless manner (FIG. 6); a
conveyor mechanism 5 which conveys the two tables 10, 20 respectively
along the two transferring passages L1, L2; a hoist mechanism 6 which
elevates and lowers the two tables 10, 20 respectively positioned in the
load/unload position P1 and the exposure position P2 so as to switch their
transferring passages; a light-transmissible plate slide mechanism 9 which
slidably opens and closes a light-transmissible plate 11 (21) and a stage
plate 12 (22) of the first table 10 (or the second table 20) when one of
the tables 10, 20 is transferred from the exposure position P2 to the
load/unload position P1; imaging means 3A and an alignment table 4 as an
alignment mechanism 3 provided in the load/unload position P1; and a
light-exposure mechanism 8 which radiates light including ultraviolet rays
and arranged in the exposure position P2. The light-transmissible plate
slide mechanism 9 consists of slide means 9A, slide actuation means 9B,
and light-transmissible plate guiding means 9C. As shown in FIG. 6, the
loop is rectangular with the first transferring passage L1 vertically
arranged on top of the second transferring passage L2. The first table 10
and the second table 20 are moved along the loop in an endless manner as
illustrated in FIG. 6.
Structures of the first table 10 and the second table 20 are described.
Because the first table 10 and the second table 20 are substantially the
same in structure except that right and left parts thereof positioned
symmetrically with respect to the conveying direction of the tables, only
the structure of the first table 10 will be described and description of
the second table 20 will be omitted.
As shown in FIGS. 1 and 2, the first table 10 includes: a frame member 16
with a U-shaped outer profile and having a mid space through which the
alignment table 4 for positioning a work W supports the stage plate 12;
the light-transmissible plate 11 and the stage plate 12 remotely and
oppositely supported by the light-transmissible plate slide mechanism 9
and the frame member 16; the slide means 9A which slidably supports the
light-transmissible plate 11 relative to the frame member 16; a conveyor
roller 14 provided at one of right and left sides with respect to the
conveying direction of the frame member 16; and an engage portion 16a
provided at a side of the frame member 16 in a position opposite to the
conveyor roller 14.
As shown in FIGS. 1 and 2, the light-transmissible plate 11 includes: a
plate member 11a made of a material that allows transmission of a certain
wave length of ultraviolet rays, such as acrylic plate, quartz glass
plate, or synthetic glass plate; a front plate-support member 11b provided
at a front side of the plate member 11a (at one side that faces the front
when the plate member 11a is conveyed from the exposure position to the
load/unload position); and positioning protrusions 11c fixed to and
horizontally extending from the front plate-support member 11b. The
positioning protrusions 11c of the upper light-transmissible plate 11 are
positioned equidistantly along the length of the front plate-support
member 11b. Each of the positioning protrusions 11c is made of a U-shaped
steel frame with a circular cross-section at an area abutting to an
abutting member 2A to be described later.
Two positioning protrusions 11c are provided in this preferred embodiment.
However, only one positioning protrusion or more than three positioning
protrusions may be provided. The positioning protrusions 11c also
functions as a handle so that a worker can grip the handle and remove the
light-transmissible plate 11 from the first table 10.
As shown in FIG. 2, a rear plate-support member 11d is fixed to a plate
receiving member 9a4 of the slide means 9A at the rear of the plate
receiving member 9a4. The light-transmissible plate 11 is placed on the
plate receiving member 9a4 with its rear side (opposite to the front
plate-support member 11b) engaged with the rear plate-support member 11d.
The rear plate-support member 11d curves upward in a shape readily
engageable with the rear side of the light-transmissible plate 11a.
The rear plate-support member 11d extends along the rear side of the light
transmissible plate 11a. However, as long as firmly engageable with the
light-transmissible plate 11a and is placed on the plate receiving member
9a4, the length and the depth of the rear plate-support member 11d that
engages with the light-transmissible plate 11a may vary. As shown in FIG.
4, along the conveying direction of the table, both sides of the
light-transmissible plate 11a are guided by L-shaped restriction member
15. The light-transmissible plate 11 is constructed so that the worker can
hold the positioning protrusions 11c and readily pull out the
light-transmissible plate 11 from the rear plate-support member 11d.
As shown in FIG. 2, the slide means 9A slides the light-transmissible plate
11 along the conveying direction with the light-transmissible plate 11
placed thereon. The slide means 9A includes: slide projections 9a1 as
slide means provided on both sides of the frame member 16; slide guides
9a2 engageable with and slidably guiding the slide projections 9a1; slide
frame 9a3 to which the slide guides 9a2 are fixed and through which the
work W and the mask M are exposed to light; the plate receiving member 9a4
formed on the top surface of the slide frame 9a3 and for placing the
light-transmissible plate 11; a stopper plate 9a5 laterally extending with
respect to the conveying direction of the slide frame 9a3; and the rear
plate-support member 11d fixed to the rear end of the plate receiving
member 9a4.
As shown in FIGS. 2 and 4, the slide frame 9a3 has a sufficient height such
that the light-transmissible plate 11 is slidable relative to the stage
plate 12 supported on the frame member 16 with the mask M and the work W
set on the light-transmissible plate 11 and the stage plate 12.
The stopper plate 9a5 slides the slide frame 9a3 along the slide
projections 9a1 when the stopper plate 9a5 abuts against an abutment stop
9b1 positioned along the second transferring passage L2 (FIG. 6). The
stopper plate 9a5 is provided at the front side of the slide frame 9a3
with respect to the conveying direction from the exposure position P2 to
the load/unload position P1. Shape and position of the stopper plate 9a5
may vary as long as it can slide the slide frame 9a3.
As shown in FIGS. 2 and 4, the stage plate 12 of the first table 10 is
placed on the plate support portion formed on the frame member 16 and has
excellent characteristics in flatness. The stage plate is provided with a
resin plate 12a, and recess portions 12c formed on the peripheral part of
the resin plate 12a. The stage plate 12 is placed on the frame member 16
with a front frame 12b crossing across the frame member 16. The front
frame 12b restricts contraction of the stage plate 12.
The recess portions 12c of the stage plate 12 engage with guide pins (guide
means) 13 projecting from the plate support portion of the frame member
16, so that the stage plate 12 is always retained in a predetermined
position. As shown in FIG. 4, the recess portion 12c has an inclined
surface at the opening thereof or the guide pin 13 has an inclined surface
from the apex to the peripheral edge. This facilitates the positioning of
the stage plate 12 when the exposure operation is completed and the vacuum
sucking of the stage plate 12 against the light-transmissible plate 11 is
disengaged. When the stage plate 12 is disengaged from the
light-transmissible plate 11 and drops on the frame member 16, the stage
plate 12 is guided in the predetermined position with the guide pins 13
inserted into the recess portions 12c.
As shown in FIGS. 2 and 4, the frame member 16 of the first table 10
remotely and oppositely supports the stage plate 12 with respect to the
light-transmissible plate 11. The frame member 16 includes a plate support
portion 16b for receiving the stage plate 12. As seen in FIG. 9A-1, the
frame member 16 is provided with the engage portion 16a at the center of
one side along the conveying direction. The engage portion 16a engages
with a hoist guide 7 of the hoist mechanism 6 to be described later, and a
first hoist rod 6f1 of the hoist mechanism 6 is fixed to the engage
portion 16a.
As shown in FIGS. 2 and 7, the conveyor rollers 14 are arranged opposite to
the engage portion 16a at two positions aligned along the conveying
direction. Each conveyor roller 14 consists of an upper roller 14a and a
lower roller 14b, both supported by an angle plate 14c. As best seen in
FIG. 11, the upper roller 14a moves along the first transferring passage
L1 while the lower roller 14b does not contact on the first transferring
passage L1. Meanwhile, the lower roller 14b moves along the second
transferring passage L2 while the upper roller 14a does not contact on the
second transferring passage L2.
As shown in FIG. 8, the suction mechanism 18 detachably sucks the work W on
the stage plate 12 against the mask M set on the light-transmissible plate
11. The suction mechanism 18 includes main suction means 18a which sucks
the mask M and the work W through the light-transmissible plate 11, the
stage plate 12 and a peripheral seal (seal rubber) 11e, and work suction
means 18b which retains the work W on the stage plate 12.
When the worker sets a work W on the stage plate 12 in the load/unload
position P1 (FIG. 9), the work suction means 18b actuates and suctions the
work W against the stage plate 12. The main suction means 18a actuates
when the mask M and the work W are sucked in an abutting manner.
With reference to FIG. 2, the light-transmissible plate slide mechanism 9,
which consists of the slide means 9A, the slide actuation means 9B, and
the light-transmissible plate guiding means 9C, will be described below.
Because the slide means 9A has been described previously, descriptions
will be made on the slide actuation means 9 B and the light-transmissible
plate guiding means 9C.
As shown in FIG. 2, the slide actuation means 9B includes: an abutment stop
9b1 positioned along the second transferring passage L2 (FIG. 6) and
protruding into and away from the sliding locus of the stopper plate 9a5;
and a drive portion 9b2 for moving the abutment stop 9b1 toward and away
from the stopper plate 9a5. The slide actuation means 9B is arranged along
the second transferring passage L2 in a position corresponding to one side
of the conveying direction of the first and second tables 10, 20. The
stopper plate 9a5 extends perpendicularly of the conveying direction of
the conveyer rollers 14 and away from the conveying direction thereof.
As shown in FIG. 2, the light-transmissible plate guiding means 9C
includes: light-transmissible plate conveying/driving means 9c1 that is
arranged along the second transferring passage L2 and downward of the
first table 10 or the second table 20 conveyed along the second
transferred passage L2; and light-transmissible plate push guide means 9c2
that is driven by the light-transmissible plate conveying/driving means
9c1 and guides the light-transmissible plate 11 toward the load/unload
position P1 with being engaged with the rear plate-support member 11d of
the light-transmissible plate 11. Herein, the light-transmissible plate
push guide means 9c2 of the light-transmissible plate guiding means 9C
also functions as push guide means for guiding the positioning protrusions
11c of the light-transmissible plate 11 against the abutting member 2A
(FIG. 3). The light-transmissible plate push guide means 9c2 may be formed
so as to rise when it pushes the rear plate-support member 11d and retract
after the push/guide operation is completed.
With reference to FIGS. 1 and 2, the imaging means 3A, the alignment table
4, and the abutting member 2A as the alignment mechanism 3 provided in the
load/unload position P1 will be described below.
The alignment mechanism 3 includes: the imaging means 3A such as a CCD
camera; and the alignment table 4 which calculates positions of the
alignment marks Mm, Wm of the mask M and the work W pictured by the
imaging means 3A to work out the distance of the work W required for
alignment and then moves the work W for alignment. In order to ensure a
good visibility of the marks Mm, Wm, the imaging means 3A utilizes
illumination which does not accelerates the exposure operation upon
picturing the alignment marks Mm, Wm. The imaging means 3A preferably
radiates a laser beam as a mark for indicating a predetermined position
where a work W is placed on the stage plate 12. A display D is positioned
above the load/unload position P1 so that the worker can visually check
the image pictured by the imaging means 3A.
As shown in FIGS. 1 and 5, the alignment table 4 includes: an
alignment/placement table 4a for placing the stage plate 12; sucking pads
4b which move through holes of the alignment/placement table 4a and suck
the stage plate 12 under vacuum on the alignment/placement table 4a; and
an alignment/drive portion 4c which moves the stage plate 12 sucked by the
sucking pads 4b and retained on the alignment/placement table 4a in the Z
axis direction (upward/downward direction), the X axis and Y axis
directions (horizontal directions perpendicular to the Z axis), and the
.theta. direction (rotational direction around the Z axis).
As shown in FIG. 3, the abutting member 2A includes: two abutment
positioning portions 2c to be guided toward and away from the positioning
protrusions 11c of the light-transmissible plate 11 positioned in the
second transferring passage L2; two base portions 2b each supporting the
abutment positioning portion 2c; and two drive portions 2a each fixed to
the base portion 2b and guiding the abutment positioning portion 2c toward
and away from the corresponding positioning protrusion 11c. Each
positioning portion 2c has two tubular surfaces arranged on one top of the
other and rotatably supported by the base portion 2b. The positioning
portions 2c may have any known shape, as long as they can stop the
positioning protrusions 11c at a predetermined position. In this preferred
embodiment, the abutting members 2A are retracted until the
light-transmissible plate 11 is conveyed to the end position of the
load/unload position P1 (FIG. 6) and are advanced by the drive portions 2a
toward the positioning protrusions 11c at the time of completing the
conveying operation of the light-transmissible plate 11 to the load/unload
position P1.
Next, the hoist guide 7, the conveyor mechanisms 5, and the hoist mechanism
6 will be described below.
As shown in FIG. 1, the hoist guide 7 includes: a slide portion 7a
engageable with the engage portion 16a, 26a of the first and second tables
10, 20 and sliding the table 10, 20; and a slide engaging portion 7b
provided on the reverse side of the slide portion 7a and slidably engaging
with the conveyor mechanism 5. The hoist guide 7 is attached to a drive
belt 5b as drive means of the conveyor mechanism 5 at a predetermined
position.
As best seen in FIGS. 1 and 13, the conveyor mechanism 5 includes: the
drive belt 5b surrounding the load/unload position P1 and the exposure
position P2; belt guides 5c supporting the drive belt 5b at a certain
height level and guiding the movement of the drive belt 5b; and a conveyor
actuator 5a which holds one of the hoist guides 7 and reciprocates the
same to drive the drive belt 5b.
The drive belt 5b is an endless belt which is provided with rugged surface
facing to the belt guides 5c and formed in a certain interval (FIG. 5).
Each belt guide 5c has gears engageable with the rugged surface of the
drive belt 5b and guiding the drive belt 5b. A linear guide 5d is fixed to
the housing 2 in the position opposite to and remote from the conveyor
actuator 5a in a manner engaging with the slide engaging portion 7b of the
hoist guide 7 and reciprocally guiding the hoist guide 7. The conveyor
actuator 5a may be of any known mechanism such as LM guide, hydraulic
cylinder, pneumatic cylinder, and feed screw mechanism, as long as it
retains the hoist guide 7 and reliably reciprocates the same.
Instead of providing a conveyor actuator 5a at one side, it is possible to
provide conveyor actuators 5a at both sides of the conveying direction of
the tables 10, 20 in a synchronized or unsynchronized manner. In the
instance where two conveyor actuators 5a are provided, the drive belt 5b
and the belt guides 5c are not required.
As shown in FIGS. 7, 10, and 11, the first transferring passage L1 extends
parallel to the transferring direction of the tables 10, 20. The first
transferring passage L1 is provided with right and left upper roller guide
rails 31 arranged between the load/unload position P1 and the exposure
position P2, cutouts 31a1 each formed in the center of the conveying
direction (longitudinal direction) of the upper roller guide rails 31,
assist rail mechanisms 35 for supplying cutouts 31a1 with auxiliary
transferring passages, and hoist assist rails 6g1, 6g2 positioned at both
ends of the respective upper roller guide rails 31 and elevated and
lowered by the hoist mechanism 6.
As seen in FIGS. 7 and 10, the upper roller guide rails 31 are fixed to the
housing 2. Each upper roller guide rail 31 has a length such that when
both tables 10, 20 are positioned in the load/unload position P1 and the
exposure position P2, one conveyor roller 14 (24) is placed on the hoist
assist rail 6g1 (6g2) and the other roller 14 (24) is placed on the cutout
31a1 (31a2). Of these upper roller guide rails 31, one of the right and
left upper roller guide rails 31 is for guiding the conveyor rollers 14 of
the first table 10, and the other of the right and left upper roller guide
rail 31 is for guiding the conveyor rolls 24 of the second table 20.
Further, each cutout 31a1, 31a2 has a length such that when both tables 10,
20 are positioned in the load/unload position P1 and the exposure position
P2, the upper roller 14a of the conveyor roller 14 and the upper roller
24a of the conveyor roller 24 can be placed thereon.
Each assist rail mechanism 35 includes: an assist rail 35b positioned in
the same plane with cutout 31a1, 31a2 of the upper roller guide rail 31;
and an assist rail drive portion 35a for retractably driving the assist
rail 35b. The assist rail mechanism 35 operates synchronously with the
hoist assist rail 6g1 (6g2) of the hoist mechanism to be described later.
The second transferring passage L2 extends under the first transferring
passage L1 and includes right and left lower roller guide rails 32 having
a transverse setting width smaller than that of the right and left upper
roller guide rails 31 of the first transferring passage L1. Of these lower
roller guide rails 32, one of the right and left lower roller guide rails
32 is for guiding the lower rollers 14b of the first table 10, and the
other of the right and left lower roller guide rails 32 is for guiding the
lower rollers 24b of the second table 20.
With reference to FIGS. 1 and 9, the hoist mechanism 6 will be described.
The hoist mechanism 6 includes: a first rotation center rod 6e1 and a
second rotation center rod 6e2 extending from the load/unload position P1
to the exposure position P2 and positioned parallel to each other below
the first and second tables 10, 20 along the conveying direction of the
tables 10, 20; plate-like first link member 6c1 and second link member 6c2
respectively fixed to the end of the first rotation center rod 6e1 or the
second rotation center rod 6e2; a first hoist rod 6f1 and a second hoist
rod 6f2 parallel to the first rotation center rod 6e1 and the second
rotation center rod 6e2 and respectively engaged with the first link
member 6c1 or the second link member 6c2; an engage rod 6d engaged with
the first link member 6c1 and the second link member 6c2 and synchronously
operating these link members 6c1, 6c2; and link drive means 6a and a push
rod 6b for rotating the first link member 6c1 and the second link member
6c2 at a certain angle around the first rotation center rod 6e1 and the
second rotation center rod 6e2 through the engage rod 6e. As best seen in
FIG. 10, the hoist mechanism 6 also engages with the hoist assist rails 6g
at the first and second link members 6c1, 6c2 and opposite to the first
hoist rod 6f1 and the second hoist rod 6f2, so as to elevate and lower the
hoist assist rails 6g.
The first hoist rod 6f1 and the second hoist rod 6f2 of the hoist mechanism
6 are respectively engaged with the engage portion 16a and the engage
portion 26a that are provided at the center of one side along the
conveying direction of the first and second tables 10, 20. Both link
members 6c1, 6c2 have a length from its rotation center such that the
first and second tables 10, 20 are switched from the first transferring
passage L1 to the second transferring passage L2 or from the second
transferring passage L2 to the first transferring passage L1. The link
member 6c1 (6c2) may have any shape, size, and arrangement, as long as it
can engage with the first hoist rod 6f1 (second hoist rod 6f2) and the
hoist assist rail 6g with the first rotation center rod 6e1 (second
rotation center rod 6e2) positioned therebetween.
With reference to FIG. 6, the light-exposure mechanism 8 will be described
below. In this preferred embodiment, the light-exposure mechanism 8 is
constructed to radiate parallel rays against the work W. However, other
known light-exposure mechanism used for the exposure apparatus may be
used, such as metal halide lamp radiating scattered light.
The light-exposure mechanism 8 includes: a discharge lamp 8a, such as a
short-arc lamp, for radiating certain wave-length of ultraviolet rays; an
elliptical reflection mirror 8b which covers the discharge lamp 8a from
the backside; fly-eye lens 8c for adjusting and equalizing the energy of
the radiated light from the discharge lamp 8a and the elliptical
reflection mirror 8b against the radiating surface; a reflection mirror 8d
for reflecting the radiation light from the fly-eye lens 8c; and a
reflection mirror 8e for reflecting the radiation light from the
reflection mirror 8d as parallel rays against the exposure position P2.
The area where the discharge lamp 8a is set and the area where the work W
is set are divided by partitions, and a non-illustrated cooling mechanism
such as a cooling fan is preferably provided to cool the area where the
discharge lamp 8a is set.
Next, various operations of the exposure apparatus 1 will be described in
relation to the load/unload operation, the alignment operation, the
hoisting operation, the conveying operation, the exposure operation, the
light-transmissible plate separating operation, and the
light-transmissible plate sliding operation.
Firstly, with reference to FIGS. 6 and 13, the whole operations of the
exposure apparatus 1 will be described.
As best seen in FIGS. 6 and 13A, a work W is loaded and aligned with the
mask M on the first table 10 in the load/unload position P1, while a work
W on the second table 20 is exposed to light in the exposure position P2.
At the start of the exposure apparatus 1, the exposure operation is not
carried out because a work W is not loaded on the second table 20. After
the alignment operation and the exposure operation are completed, as shown
in FIG. 13B, the first table 10 rises to the first transferring passage L1
through the hoist guide 7 and by the hoist mechanism 6, while the second
table 20 lowers to the second transferring passage L2 through the hoist
guide 7 and by the hoist mechanism 6.
As shown in FIG. 13C, the first table 10 is then transferred to the
exposure position P2 along the first transferring passage L1 by means of
the conveyor mechanism 5. Meanwhile, the second table 20 is transferred to
the load/unload position P1 along the second transferring passage L2 by
means of the conveyor mechanism 5. When doing so, by the
light-transmissible plate slide mechanism 9 the light-transmissible plate
21 of the second table 20 slides off from the stage plate 22 in the
reverse direction of the conveying direction of the second table 20, and
the stage plate 22 is transferred to the load/unload position P1.
Meanwhile, by the light-exposure mechanism 8 the exposure operation is
applied to the first table 10 that has been transferred to the exposure
position P2.
As shown in FIGS. 13D and 6, when a work W is loaded on the stage plate 22
of the second table 20 that has been transferred to the load/unload
position P1, the light-transmissible plate slide mechanism 9 slides the
light-transmissible plate 21 toward the stage plate 12 so that the
alignment operation is performed through the alignment mechanism 3 and the
alignment table 4. As shown in FIG. 13E, the second table 20 that is
positioned in the load/unload position P1 and to which the alignment
operation has been applied rises to the first transferring passage L1
through the hoist mechanism 6. Meanwhile, the first table 10 that is
positioned in the exposure position P2 and to which the exposure operation
has been applied lowers to the second transferring passage L2 through the
hoist mechanism 6.
As shown in FIGS. 13F and 6, the first table 10 is then transferred to the
load/unload position P1 along the second transferring passage L2 by means
of the conveyor mechanism 5. Meanwhile, the second table 20 is transferred
to the exposure position P2 along the first transferring passage L1 by
means of the conveyor mechanism 5. When doing so, by the
light-transmissible plate slide mechanism 9 the light-transmissible plate
11 of the first table 10 slides off from the stage plate 12 in the reverse
direction of the conveying direction of the first table 10, and the stage
plate 12 is transferred to the load/unload position P1. The worker then
removes the exposed work W from the stage plate 12 and sets another work W
on the stage plate 12. As shown in FIGS. 13G and 6, when the work W is set
on the stage plate 12 of the first table 10, the light-transmissible plate
slide mechanism 9 slides the light-transmissible plate 11 toward the stage
plate 12 so that the alignment operation is performed through the
alignment mechanism 3 and the alignment table 4.
The exposure apparatus 1 alternately carries out the alignment operation
and the exposure operation on the work W with the aforementioned
operations illustrated in FIGS. 13A through 13G being repeated. Each of
the aforementioned operations will be described in detail.
Loading Operation of Work W
As shown in FIGS. 1 and 6, the first table 10 and the second table 20 are
respectively positioned in the load/unload position P1 and the exposure
position P2 arranged at both conveying ends of the first and second
transferring passages L1, L2. In the load/unload position P1, the first
table 10 is ready to place a work W on the stage plate 12 with the
light-transmissible plate 11 slid off from the stage plate 22. In order to
specify the alignment mark Wm of the work W, non-illustrated laser
radiation means of the alignment mechanism 3 radiates an infrared laser
beam. The worker places a work W on the stage plate 12 of the first table
10 in alignment with the alignment mark Wm.
When the work W is placed on the stage plate 12, the exposure apparatus 1
operates such that the work suction means 18b of the suction mechanism 18
actuates and sucks the work W on the stage plate 12. At the same time, as
shown in FIGS. 12C-1 through 12D-2, the light-transmissible plate
conveying/driving means 9c1 of the light-transmissible plate slide
mechanism 9 operates such that the light-transmissible plate push guide
means 9c2 pushes the rear plate-support member 11d of the
light-transmissible plate 11 and slides the slide frame 9a3 along the
slide projections 9a1 until the mask M of the light-transmissible plate 11
faces to the work W of the stage plate 12.
When the mask M faces to the work M, the exposure apparatus 1 actuates the
drive portions 2a of the abutting member 2A, so that the abutment
positioning portions 2c advance to abut against the positioning
protrusions 11c of the first table 10, as illustrated in FIG. 3. When
doing so, the light-transmissible plate push guide means 9c2 (FIG. 12D-2)
continuously pushes the rear plate-support member 11d of the
light-transmissible plate 11, thereby positioning the light-transmissible
plate 11 in the predetermined abutting reference position.
Alignment Operation
As best seen in FIGS. 8A and 8B, when the light-transmissible plate 11 to
which the mask M has been set is positioned, the sucking pads 4b of the
alignment table 4 (FIG. 5) rise to suck and retain the stage plate 12. At
the same time, the alignment/placement table 4a rises so that the stage
plate 12 is elevated remotely from the plate support portion of the frame
member 16 until the work W abuts against the mask M. When the mask M and
the work W abut to each other, the main suction means 18a actuates to
retain the mask M and the work W under vacuum.
The alignment mechanism 3 pictures the alignment marks Mm, Wm of the mask M
and the work W (FIG. 1). If the alignment marks Mm, Wm are not within the
allowable range, the exposure apparatus 1 calculates the distance required
for alignment and transmits a signal to the alignment table 4. Thereafter,
as seen in FIG. 8C, the exposure apparatus 1 disengages the retention of
th
