JPH02230250A - Screen mask plate making method - Google Patents

Abstract

PURPOSE:To improve the dimensional accuracy of pattern disposition by imposing an intermediate plate on a screen mask body and vacuum sucking a rubber sheet in the state of providing a spacing between a frame body having grooves corresponding to a frame and the frame and putting the rubber sheet on the frame. CONSTITUTION:The intermediate plate 35 is imposed on the screen mask body 24 and the frame body 36 having the grooves 37 corresponding to the frame body 23 is provided with the spacing 39 between the grooves 37 and the frame 23. While the rubber sheet 18 is held put on the frame 23, the rubber sheet is vacuum-sucked. The intermediate plate 35, therefore, limits the exertion of the influence of the expansion of the rubber sheet 18 on the unexposed screen mask 24 and the frame body 36 limits the exertion of the influence of the expansion of the rubber sheet 18 on the frame 23. Since the unexposed screen mask is thereby adhered and fixed to the film mask without expanding, the higher accuracy of the pattern disposition is obtd.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a method for making a screen mask used in a screen printing machine that prints patterns for hybrid ICs, etc., which enables improved dimensional accuracy of pattern placement and good exposure of fine patterns. With the purpose of In the screen mask plate making method in which the pattern of the film mask is transferred to the screen mask body by exposing from the film mask side, an intermediate plate is placed on the screen mask body, and a groove corresponding to the frame is formed. The rubber sheet is vacuum-suctioned while the frame body is placed over the frame with a gap between the groove and the frame.

(Field of Application of Chestnuts) The present invention relates to a method for making a screen mask for use in a screen printing machine that prints patterns for hybrid ICs and the like.

FIG. 8 shows how the screen mask is used.

Reference numeral 1 denotes a screen mask, in which a screen mask main body 2 on which a predetermined pattern is formed is stretched over a frame 3.

The screen mask 1 is set on a substrate 5 fixed on a table 4. When the squeegee 6 is scanned, the paste 7 is applied to the printed circuit board 5 in a pattern corresponding to the pattern of the screen mask body 2.

In recent years, with the increase in the degree of integration of hybrid ICs, screen masks are required to have higher precision in pattern arrangement and finer patterns. Regarding the accuracy of pattern placement, it is necessary to have an accuracy of about ±50μ between patterns separated by 500s+IIft.

For making screen masks, use an unexposed mask and a film mask in W! It consists of a step of attaching the film to light and exposing it to light, and a subsequent water development step. As will be described later, the exposure process is important for improving dimensional accuracy.

In addition, there are two types of screen mask main bodies: stainless steel wire mesh and Tetron (registered trademark) thin wire mesh.The former does not stretch and is convenient for improving the above-mentioned dimensional accuracy, but is expensive. Therefore, it has been desired to realize an exposure method that can improve dimensional accuracy even when using the latter method, which is inexpensive.

[Conventional technology]

Figure 9 (A). (B) shows a conventional screen mask plate making method, and FIG. 10 shows an apparatus used in the screen mask exposure method.

First, the schematic structure of the screen mask exposure apparatus will be explained with reference to FIG.

In FIG. 10, 10 is a box-shaped exposure device main body, 11 is an upper lid,
12 is a glass plate.

13 is a mercury lamp, 14 is a reflecting mirror, 15 is a vacuum suction pump, and 16 is a suction hole, all of which are provided in the main body 10 of the apparatus.

The upper l111 is provided so as to be openable in the direction of the arrow with one side thereof as an axis, and the frame 17 has a structure in which a rubber sheet 18 is stretched.

Next, the conventional plate making (kasumi light) method will be explained.

As shown in FIG. 9(A), a film mask 20 with a predetermined pattern formed thereon is placed on the glass plate 12, and an unexposed screen mask (gFiPs version) is placed over this.
21, cover the sponge sheet 22, close the top lid 11, and cover the rubber sheet 18.

The unexposed screen mask 21 is, for example, 8708×8
A 70 m rectangular aluminum frame 23 is covered with an unexposed screen mask body 24 made of a Tetron (registered trademark) fine wire mesh film coated with a photosensitive resin or diazo emulsion. It is.

In this state, a suction operation is performed as shown by arrow 25.

As a result, as shown in the same figure (B), the rubber sheet 18
is adsorbed onto the glass plate 12, and the unexposed screen mask 21 is tightly fixed on the glass plate 12 by being in close contact with the film mask 20 due to atmospheric pressure, and in this state, the mercury lamp 13 is
Expose to light.

Thereafter, the suction is stopped, the upper M11 is opened, the screen mask 21 is taken out, and a screen mask is obtained by developing with water.

[Problem to be solved by the invention]

Due to the above suction operation, the rubber sheet 18 is moved by the arrow 26a
Stretch as shown at ~26d.

Unexposed screen mask body 25 out of rubber sheet 18
The expansion of the portion 18a facing the is transmitted to the unexposed screen mask main body 24 via the compressed sponge sheet 22, and this is expanded in all directions. Further, due to the expansion of the opposing portions 18b of the frame 23, the frame 22 is deformed in the direction of expansion, and the screen mask main body 24 is also expanded thereby.

When suction is stopped, the screen mask returns to its original dimensions. In this state, it is set on a screen printing machine.

Since exposure is performed with the screen mask main body 24 stretched, the dimensional accuracy of the screen mask produced is
In the direction (see FIG. 10), as shown by the middle line a in FIG. 4, the Y direction (see FIG. C) was also poor, as shown by the middle line ■a in FIG. This is the dimensional error of the dimension between the patterns formed on the plate-made screen mask with respect to the dimension between the corresponding patterns of the film mask, both in the short direction, and about 3 at 500 am.
The dimensional error was as large as 0.00 to 400 μm.

Note that if the vacuum is weakened, the stretch of the rubber sheet 18 will be reduced, and accordingly, the unexposed screen mask body 2 will be
The degree of stretching of the film mask 20 is also reduced, and the dimensional error between the patterns described above can be reduced.
As a result, the resolution of exposure of the fine pattern decreases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a screen mask plate making method that enables improvement in the dimensional accuracy of pattern arrangement and good exposure of fine patterns.

[Means to solve problems]

The present invention (invention of claim 1) provides vacuum suction on a rubber sheet covering the unexposed screen mask in which the unexposed screen mask main body is stretched over a frame to tightly fix the unexposed screen mask to the film mask. and exposing the screen mask from the film mask side to transfer the pattern of the film mask onto the screen mask main body, the method comprising: placing an intermediate plate on the screen mask main body; The rubber sheet is vacuum-suctioned while a frame body having a corresponding frame is placed over the frame with a gap between the frame and the frame.

The present invention (invention of claim 2) provides vacuum suction on a rubber sheet covering an unexposed screen mask in which an unexposed screen mask main body is stretched over a frame to tightly fix the unexposed screen mask to a film screen. In the screen mask plate making method, in which the screen mask is exposed from the ten film mask side to transfer the pattern of the film mask onto the screen mask main body, an intermediate plate is placed on the screen mask main body, and an intermediate plate is placed on the screen mask main body. The rubber sheet is configured to be vacuum-suctioned while placed at the same height.

The present invention (invention of claim 3) is configured to perform vacuum suction from four locations on all sides.

[Effect]

In the invention of claim 1, the intermediate plate limits the effect of the stretching of the rubber sheet on the unexposed screen mask by υ1.

The frame limits the influence of the stretching of the rubber sheet on the frame.

As a result, the unexposed screen mask is tightly fixed to the film mask without being stretched.

In the invention according to claim 2, the intermediate plate having approximately the same height as the frame,
To limit the influence of stretching of a rubber sheet on an unexposed screen mask, and to reduce the degree of deformation of the rubber sheet to limit deformation of a frame.

In the third aspect of the invention, suction from four locations strengthens the close contact between the unexposed screen mask body and the film mask.

〔Example〕

FIG. 1 shows a first embodiment of the screen mask plate making method of the present invention. Figure 2 shows a cover that can be applied to this plate-making method, and Figure 3 (A). (B) shows a state in which an unexposed screen mask is set in an exposure device.

First, the screen mask exposure device 30 will be explained with reference to FIG.

This screen mask exposure device 30 has suction holes 31 to 3.
4 was provided at each of the four corners of the glass plate 12.
It has the same configuration as that shown in Figure 0.

Corresponding parts are denoted by the same reference numerals, and their explanation will be omitted.

Next, the plate making (exposure) method will be explained. First, as shown in FIG. 3(A) and FIG. 1, a film mask 20 is placed on a glass plate 12, and an unexposed screen mask (so-called PS plate) 21 is placed on top of this by 4! The sponge sheet 22 is placed on the unexposed screen mask body 24.

Furthermore, the intermediate plate 35 is fitted into the frame 23 and placed on the sponge sheet 22. The intermediate plate 35 is an acrylic resin plate with a thickness of about 5 aw, and has the role of limiting the influence of the stretching of the rubber sheet from reaching the unexposed mask body 24, as will be described later.

Furthermore, the frame 36 is placed over the frame 23.

This frame body 36 has a groove 3 that is one size larger than the frame 23.
7, and is positioned and placed on the intermediate plate 35 in a state floating above the glass plate 12, as shown in FIG. state. The frame body 36 is made of vinyl chloride, for example, and has the function of protecting the frame 23 from the effects of stretching of the rubber sheet, as will be described later.

After this, the upper M11 is closed and covered with the rubber sheet 18.

FIG. 3(A) shows the set state at this time.

In this state, a suction operation is performed as shown by arrow 38.

As a result, as shown in FIGS. 1 and 3(B), the rubber sheet 18 is attracted onto the glass plate 12, and the unexposed film mask 21 is tightly attached to the glass plate 12 together with the film mask 20 due to atmospheric pressure. Fixed.

The unexposed mask body 24 is pressed through the intermediate plate 35 and is brought into close contact with the glass plate 12.

The sponge sheet 22 is compressed, and the frame 36 is lowered and comes into contact with the glass plate 12. Even in this state, the frame 36 and the frame 2
3, there is still a non-contact relationship with the gap 39 over the entire circumference.

The rubber sheet 18 expands as shown by arrows 26a to 26d in the same manner as described above.

The portion 18a of the rubber sheet 1B facing the unexposed mask body 24 is indicated by the arrow 26a. Although it stretches as shown by 26b, the intermediate plate 35 does not stretch at all because it is a rigid plate as described above.

The unexposed mask body 24 is pressed through the intermediate plate 35, and since this intermediate plate 35 does not stretch, the expansion of the rubber sheet 18 does not affect the unexposed mask body 24.

Also, the portion 1 of the rubber sheet 18 that is in close contact with the frame 36
8b also expands as shown by arrows 26c and 26d. Even if the frame 36 is slightly deformed in the direction of expansion due to this expansion, no force is applied to the frame 23 due to the existence of the gap 39, and the frame 23 is not deformed at all.

As described above, since no stretching force is directly applied to the unexposed mask body 24 and the frame 23 is not deformed, the unexposed mask body 24 is brought into close contact with the film mask 20 without being stretched at all.

In this state, exposure is performed using a mercury lamp 13.

After this, the suction is stopped, the upper part 1111 is opened, the mask is taken out, and a screen mask is obtained by water development.

Therefore, no expansion or contraction occurs in the unexposed mask body 24 during the screen mask plate making process, and the dimensional accuracy of the pattern arrangement of the screen mask during plate making is significantly improved compared to conventional ones.

FIGS. 4 and 5 show the measurement results, respectively.

The line work in Figure 4 is X7], and the dimensional accuracy is improved. As can be seen from the wirework, the dimensional error is several tens of μm for 500M.

The line ■ in FIG. 5 indicates the dimensional accuracy in the Y direction. As can be seen from the line ■, the dimensional error is several tens of micrometers in order of 500.

Further, suction of the rubber sheet 18 is simultaneously performed at four locations at its four corners.

For this reason, the unexposed mask body 24 and the film mask 20 are brought into close contact more uniformly and more strongly over the entire surface than when suction is performed at one location.

This makes it possible to make fine patterns with higher resolution than in the past.

Although the degree of expansion of the rubber sheet 18 increases as the suction force increases, the intermediate plate 35 and the frame 36 described above
Due to the presence of the unexposed mask body 24, expansion is restricted, and the dimensional accuracy of the pattern is not affected. It is also possible to perform suction at one location.

FIG. 6 shows a second embodiment of the screen mask plate making method of the present invention. Figure 7<A). (B) shows a state in which an unexposed mask is set in an exposure device. In each figure, Figures 1 and 3
Components corresponding to those shown in the figure are given the same reference numerals.
The explanation will be omitted.

First, as shown in FIG. 7(A) and FIG. 6, the film mask 20 and the unexposed mask 21 are placed on top of each other on the glass plate 12, and then the film is fitted into the frame 23. A sheet 50, a polyethylene foam board 51, and an acrylic board 53 are stacked and placed on the unexposed mask body 24. The physical height of the acrylic plate 53 is made to be approximately at the same height as the upper surface of the frame 23. In this embodiment, the dimensions are slightly higher.

The film sheet 50, the polyethylene foam board 51, and the acrylic board 53 constitute an intermediate board 53 as a whole.

When the upper 11fl1 is closed, it is covered with a rubber sheet 18, and the seventh
The state shown in Figure (A) is reached.

The rubber sheet 18 contacts and covers the acrylic plate 52 and the frame 23, and no space is formed below the portion surrounded by the frame 23.

When the suction operation is performed in this state, as shown in Figs. 6 and 7 (
As shown in B), the rubber sheet 18 is attracted and the unexposed mask 21 is closely fixed on the glass plate 12 together with the film mask 20 by atmospheric pressure.

The unexposed mask body 24 is pressed through the intermediate plate 53. Transmission of the influence of the elongation of the rubber sheet 18 is blocked at the intermediate plate 53 and does not reach the unexposed mask body 24.

Further, the lower side of the portion of the rubber sheet 18 corresponding to the inside of the frame 23 is occupied by the intermediate plate 53 and is not a space.

Therefore, the degree of deformation of the rubber sheet 18 during suction is small, and the force acting on the frame 23 to distort it in the direction of expansion is also small ( The dimensional accuracy of the pattern arrangement of the plate-made screen mask is almost the same as shown by lines I and II in FIGS. 4 and 5, and is good. The degree of adhesion between the film mask body 24 and the film mask 20 is good, and fine patterns can also be exposed with good resolution.

Further, in this embodiment, the frame 36 in FIG. 1 is not used,
Since the intermediate plate 53 is simply placed, the workability is good.

〔Effect of the invention〕

As explained above, according to the invention of claim 1, the unexposed screen mask main body is not affected by the stretching of the rubber sheet and is closely fixed to the film mask without any stretching, and thereby the screen mask that is made into a plate is It is possible to achieve 8-accuracy pattern placement.

According to the invention of claim 2, since the frame body in the invention of claim 1 is not used, it is easy to perform the work of preparing for exposure in which the unexposed screen mask body is closely fixed to the film mask,
Exposure can be performed efficiently.

According to the third aspect of the invention, the degree of adhesion between the unexposed screen mask body and the film mask is strong, and even fine patterns can be plate-made with good resolution.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a first embodiment of the screen mask plate making method of the present invention, Fig. 2 is a diagram showing a screen exposure device applicable to the plate making method shown in Fig. 1, and Fig. 3 is a diagram showing the time of exposure. Figure 4 is a diagram showing the accuracy of pattern placement in the X direction of the screen mask, Figure 5 is a diagram showing the accuracy of pattern placement in the Y direction of the screen mask, Figure 6 is a diagram showing the accuracy of pattern placement in the Y direction of the screen mask. 7 is a diagram showing the second embodiment of the screen mask plate making method of the present invention, FIG. 7 is a diagram showing the suction and fixing state of the screen mask during exposure, FIG. 8 is a diagram explaining the screen mask, and FIG. 9 is a diagram showing the conventional method. FIG. 10 is a diagram showing an apparatus applicable to the conventional screen mask making method. In the figure, 11 is a top lid, 12 is a glass plate, 13 is a mercury lamp, 15 is a vacuum suction bomb, 18 is a rubber sheet, 20 is a film mask, 21 is an unexposed screen mask (PS version), 23 is a frame, and 24 is a frame. The unexposed screen mask body, 26a to 26d are arrows indicating the elongation of the rubber sheet, 30 is the screen mask exposure device, 31 to 34 are suction holes, 35.53 is an intermediate plate, 36 is a frame body, 37 is a groove, 38 39 is an arrow indicating suction, 39 is a gap, 50 is a film sheet, 51 is a polyethylene foam board, and 52 is an acrylic board. Patent applicant: Fujitsu Ltd. 5C)) 600 mm Fig. 4 Fig. 1 + A + Fixed E-saki, yjijio's 11th figure 9

Claims (1)

[Claims] (1) The unexposed screen mask body (24) is attached to the frame (2).
3) Unexposed screen mask (21) stretched over
The unexposed screen mask is tightly fixed to the film mask (20) by vacuum suctioning the rubber sheet (18) that covers it, and the screen mask is exposed from the film mask side to change the pattern of the film mask to the screen mask. In a screen mask plate making method for transferring onto a main body (24), an intermediate plate (35) is placed on the screen mask main body (24), and a frame has a groove (37) corresponding to the frame (23). (3
6) with a gap (39) between the groove (37) and the frame (23).
) A screen mask plate making method characterized by vacuum suctioning the rubber sheet (18) while covering the rubber sheet (18). (2) The unexposed screen mask body (24) is placed in the frame (2)
3) Unexposed screen mask (21) stretched over
The unexposed screen mask is tightly fixed to the film mask (20) by vacuum suctioning the rubber sheet (18) that covers it, and the screen mask is exposed from the film mask side to change the pattern of the film mask to the screen mask. In the screen mask plate making method of transferring onto the main body (24), the intermediate plate (53) is placed on the screen mask main body (24) at approximately the same height as the frame (23), and the rubber sheet (18 ) is vacuum-suctioned. (3) The screen mask plate making method according to claim 1 or 2, wherein the vacuum suction is performed from four locations (31 to 34) on all sides.