JP2000006363A - Method for coating board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a thickness of an insulating resin layer formed in a printed board state having a waveform protrusion and recess surface by supplying a coating material to an area to be coated with a coating material via a mask member having a stitched interstice part of the same thickness as that of a mask part, and then flowing the material on the board. SOLUTION: A printed board 2 is fixed onto a base 20 by a vacuum sucking mechanism. Then, after a mask 1 is placed at a predetermined position of the board 2, a predetermined amount of an insulating resin 4 is supplied to a sweeping starting part of the mask 3. Thereafter, a coating bar 3 is pressed to the mask 2, swept on an upper surface of the board 2 to fill the resin 4 in an opening 22. Then, when the mask 1 is removed from the board 2, the resin 4 becomes the state that stitched interstice part 12 is coated with the resin 4. When the resin 4 coating the board 2 is flowed by a vibration generating controller 30, the resin 4 flows out to adjacent spaces by its vibration so that the adjacent resins 4 bury the spaces to become flat. Thereafter, it is prebaked under predetermined conditions to obtain a dried coating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a resin to a substrate, and more particularly to an improvement in a method for applying an insulating resin to an IC substrate or a printed circuit board.

[0002]

2. Description of the Related Art In a multilayer printed circuit board, a plurality of printed circuit boards are laminated via an insulating resin layer. Recently, the number of layers has increased and the thickness of the multilayer printed circuit board has increased. However, devices mounting these multilayer printed circuit boards have been reduced in size and weight. For this reason, it is necessary to make the insulating resin layer as thin as possible and to obtain the necessary insulation resistance. This insulating resin layer is made as follows.

FIG. 6 is an explanatory view of a coating method using a conventional mask body. 1 is a mask body, 11 is an opening of the mask body, 2 is a printed board, 3 is a coating bar, 4 is an insulating resin,
M is the moving direction of the coating bar. The mask body 1 is made of stainless steel having a thickness of about 0.2 mm and has an opening 11 having the same shape as the shape of the application area on the printed circuit board 2. The coating bar 3 is a stainless material having a thickness of about 10 mm. The insulating resin 4 is a polyimide resin varnish.

After mounting the printed board 2 on a base (not shown), the printed board 2 and the mask body 1 are aligned. Next, the insulating resin 4 is supplied through the mask body 1. Further, when the coating bar 3 is moved on the mask body 1 in the direction of arrow M while pressing the upper surface of the mask body 1, the supplied insulating resin 4 fills the opening 11 of the mask body. Therefore, the insulating resin 4 is applied to a desired area on the printed board 2.

Next, when the mask 1 is removed from the printed board 2, an insulating resin 4 film can be formed in the opening 11 of the mask.

[0006]

FIG. 7 is a cross-sectional view of a conventional mask body and a printed circuit board. The drawings are enlarged views of main parts of the printed circuit board for easy understanding of the contents. However, as shown in FIG. 7A, the surface of the printed circuit board 2 has corrugations. The distribution of this unevenness is ± 100
μm.

The mask body 1 has a thin plate shape. When the mask body is placed on such a printed board 2, the mask body 1 becomes corrugated along with the corrugations of the printed board 2. Then, the coating bar 3 is moved while being pressed against the uneven mask body 1. Then, the insulating resin 4 fills the opening 11 of the mask body. As a result, FIG.
As shown in (b), the film thickness of the insulating resin 4 in the opening 11 on the printed circuit board 2 becomes non-uniform at the substantially central part and the substantially end part.

The thickness of the insulating resin 4 becomes more non-uniform as the width of the opening 11 increases. In other words, the film thickness distribution tends to increase. This is because when the width of both ends supporting the coating bar 3 when the coating bar 3 is moved on the mask body 1 while pressing the upper surface of the mask body 1 is increased, the bending amount of the coating bar 3 increases. As a result, if the film thickness of the insulating resin 4 becomes non-uniform, the insulation resistance at each location differs, and the expected insulation resistance value cannot be maintained.

It is an object of the present invention to prevent a film thickness from becoming nonuniform even when an insulating resin is applied to the surface of a printed circuit board having corrugated irregularities, and to obtain a uniform insulation resistance value. As a result, a high-quality multilayer printed circuit board is provided.

[0010]

The invention described in the claims is
In a method in which a mask member having an opening formed in an application region is placed on a substrate and a coating material is applied through the mask member, a stitch-shaped opening having the same thickness as the mask portion is formed in the region where the coating material is applied. After the coating material is supplied through the provided mask member, a fluidizing process is performed on the coating material on the substrate to make the thickness uniform, thereby providing a substrate coating method. Therefore, since the opening region of the mask member has a stitch portion, the width of both ends supporting the coating bar is reduced,
The amount of deflection of the coating bar does not increase. Then, the thickness of the coating material on the substrate can be made uniform.

[0011]

Embodiments of the present invention will be described with reference to the drawings. <First Embodiment> FIG. 1 is an explanatory view of a method for applying a resin to a printed circuit board according to a first embodiment. 1 is a mask body, 11
Is an opening of the mask body, 12 is a stitch portion of the opening, 2 is a printed board, 3 is a coating bar, 4 is an insulating resin, 20 is a base, 30 is a vibration generation controller, and M is a moving direction of the coating bar. is there.

The size of the printed board 2 is 510 mm in width, 340 mm in length, and 0.8 mm in thickness of a BT resin material (CC manufactured by Mitsubishi Gas Chemical Co., Ltd.).
L-HL830). Next, the coating bar 3 is made of stainless steel having a width of 510 mm, a width of 45 mm, and a thickness of 10 mm, and a portion for pressing the mask body 1 or the insulating resin 4 is a smooth straight line. It is connected to a drive device (not shown) and moves on the mask body 1 in the direction of arrow M while pressing the upper surface of the mask body 1.

The insulating resin 4 is a polyimide resin varnish (PIX-3400 manufactured by Hitachi Chemical Co., Ltd., resin content 18.5 wt%,
Solvent N-methyl-2-pyrrolidone, viscosity 7500 cps). Further, the base 20 is, for example, a base of a printing machine for holding the printed circuit board 2, and more specifically, a base with a vacuum suction mechanism. Further, an ultrasonic vibrator controlled by the vibration generation controller 30 is provided, and the printed circuit board 2 is vibrated. However, not only ultrasonic vibration but also mechanical vibration may be applied as long as vibration can be applied to the printed circuit board 2.

FIG. 2 is a plan view of the mask body according to the first embodiment. The mask body 1 is made of stainless steel having a plate thickness of about 300 μm.
It is 280mm. The shape of the stitch portion 12 in the opening 11 is a regular hexagon having a width W2 of 300 μm and a side width W3 of 20 mm. The thickness of the stitch part 12 is the same as that of the mask body 300
μm. And this regular hexagon is a front and back through hole.

Next, a method of applying a resin to a printed circuit board will be described. FIG. 3 is an explanatory diagram of a state of filling the insulating resin according to the first embodiment. The drawings are enlarged views of the main parts of the printed circuit board for easy understanding of the contents. The printed circuit board 2 is fixed on the base 20 by a vacuum suction mechanism. Next, the mask body 1 is placed at a predetermined position on the printed board 2. Then, a predetermined amount of, for example, 10 g of the insulating resin 4 is supplied to the sweep start portion of the mask body 1.

As shown in FIG. 3A, the coating bar 3 is pressed against the mask body 1 at 0.6 kg / cm 2, and the upper surface of the printed circuit board 2 is swept at a sweep speed of 8 mm / min. The resin 4 is filled. The coating bar 3 moves along the upper surface of the mask body 1, and also moves along the stitches 12 in the opening 11 when the coating bar 3 reaches the opening 11. Therefore, since the mask body 1 and the stitch portion 12 are provided with the same thickness, the amount of bending of the coating bar 3 does not increase.

As a result, the insulating resin 4 can be uniformly filled in the opening 11. Thereafter, as shown in FIG. 3B, when the mask body 1 is removed from the printed circuit board 2, the insulating resin 4 is applied to the desired position on the printed circuit board 2 in the stitches 12. FIG. 4 is a cross-sectional view showing a state of filling the insulating resin according to the first embodiment. As shown in FIG. 4A, when the mask body 1 is removed from the printed board 2, the insulating resin 4 is applied to the stitches 12.

Next, the vibration generation controller 30 controls the resin applied to the printed circuit board 2 to fluidize the resin 47 k
Give a Hz ultrasonic wave. Therefore, as shown in FIG. 4B, the insulating resin 4 flows out into the adjacent space by the vibration.

Further, as shown in FIG. 4C, when ultrasonic vibration is applied for 2 minutes, the adjacent insulating resins 4 fill the space and become flat. Thereafter, the film was prebaked in an oven at 120 ° C. for about 10 minutes to obtain a dried coating film. As a result, the coating had an average thickness of 80 μm and a thickness distribution of ± 6 μm. Comparative Example 1 The mask body 1 used in Comparative Example 1 had a thickness of about 30
The opening 11 has a width W1
Is 450 mm and the vertical width L1 is 280 mm, which is the same as in the first embodiment. However, the stitches 12 in the openings 11 of the mask body 1 are not provided. Except for this difference, the printed circuit board 2 was manufactured in the same manner and in the same manner as in the first embodiment.

As a result, the thickness distribution of the coating film on the printed circuit board 2 was ± 30 μm. First Example and Comparative Example 1
The following can be determined by comparing and examining. Opening 11
Since the stitches 12 having the same thickness as the mask body 1 are provided in the first embodiment, the bending amount of the coating bar 3 does not increase. Therefore, the thickness of the coating liquid on the substrate can be made uniform. <Second Embodiment> The difference from the first embodiment is that the insulating resin 4 is made of a photosensitive polyimide resin varnish (UR-3 manufactured by Toray Industries, Inc.).
140 resin content 17 wt%, solvent N-methyl-2-pyrrolidone,
The viscosity is 5000 cps) and the structure of the mask body 1 is different.

FIG. 5 is a structural view of a mask body according to the second embodiment. The mask body 1 is made of stainless steel having a plate thickness of about 300 μm, and the shape of the opening 11 is the same as that of the first embodiment.
The length L1 is 450 mm and the length L1 is 280 mm. The shape of the stitch portion 12 in the opening 11 of the mask body 1 is 80 mm in width W4.
Inside, five blocks of stitches 12 are provided at intervals of 10 mm for W6. For details of one block, the width W5 is 20 μm and the vertical width is L2.
Is a stitch portion 12 having eight slits of 280 mm.
Also, the moving direction of the coating bar 3 is the extension direction of the slit,
The pattern has no stitches in the direction perpendicular to the moving direction. Except for this difference, the same as in the first embodiment, the insulating resin 4 was filled in the opening 11 of the mask on the printed circuit board 2.

After being left for 10 minutes as a fluidization treatment, the film was prebaked at 80 ° C. for about 10 minutes to obtain a dried coating film.
This coating has an average thickness of 25 μm and a thickness distribution of ± 5 μm.
Met. <Comparative Example 2> The difference from the second embodiment is that, after the insulating resin 4 is filled in the opening 11 of the printed circuit board 2, the vibration is not immediately applied and about 1 hour in an oven at 120 ° C.
This is the point of prebaking for 0 minutes.

As a result, the shape of the stitch portion 12 in the opening 11 remained in the coating film. When the second embodiment is compared with the comparative example 2, the following can be determined. After filling the opening 11 of the printed circuit board 2 with the insulating resin 4, a fluidizing process such as applying vibration or leaving the resin for a predetermined time is performed.
It is necessary to make the thickness of the coating liquid supplied to the printed circuit board 2 flat. <Third Embodiment> The difference from the first embodiment is that the insulating resin 4 is a photoresist AZ-PLP30 (resin content: 31.5 wt%, manufactured by Hoechst Industry Co., Ltd., solvent propylene glycol monomethyl ether acetate, viscosity: 830 cps). Is that

After filling the opening 11 of the printed circuit board 2 with the insulating resin 4, it is subjected to fluidization treatment, ultrasonic vibration of 47 kHz is applied for 1 minute, and further prebaked at 90 ° C. for about 10 minutes to form a dried coating film. Obtained. As a result, this coating has an average thickness of 50 μm.
And the film thickness distribution was ± 4 μm. Comparing the third embodiment, it can be determined that the insulating resin 4 having a low viscosity may be used.

[0025]

As described above, according to the present invention, even if an insulating resin is applied to the surface of a printed circuit board having corrugated unevenness, the film thickness distribution is prevented from becoming non-uniform, and the expected predetermined value is obtained. Can be obtained. As a result, a high quality printed circuit board can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method for applying a resin to a printed circuit board according to a first embodiment,

FIG. 2 is a plan view of a mask body according to the first embodiment,

FIG. 3 is an explanatory diagram of a state of filling an insulating resin according to the first embodiment,

FIG. 4 is a cross-sectional view illustrating a state of filling an insulating resin according to the first embodiment;

FIG. 5 is a structural diagram of a mask body according to a second embodiment,

FIG. 6 is an explanatory view of a coating method using a conventional mask body,

FIG. 7 is a cross-sectional view of a conventional mask body and a printed circuit board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mask body 11 Mask body opening 12 Stitch part of mask body opening 2 Printed circuit board 3 Coating bar 4 Insulating resin 20 Base 30 Vibration generation controller

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Machida 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa F-term in Fujitsu Limited (reference) 2C035 AA06 FA30 FD01 FD44 FF04 FF22 FF26 5E346 AA12 DD03 GG19 HH11

Claims (1)

[Claims] 1. A method of placing a mask member having an opening in an application region on a substrate and applying a coating material through the mask member, wherein the mask material has the same thickness as the mask portion in the region where the coating material is applied. A coating method for a substrate, comprising: supplying a coating material through a mask member provided with a stitch-shaped opening; and applying a fluidizing treatment to the coating material on the substrate to make the thickness uniform.