JP2004114327A - Printing plate and printing method using the plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing plate which prevents a high viscosity paste sticking to a squeegee edge from residing existing over a through hole in a circuit board during packing the paste in a squeegee process. <P>SOLUTION: A metallic sheet 3 which forms a squeegee cleaning part 7 is anchored to the back of an inclined part 5 of a mask 2 for a plate frame 1 and after the high viscosity paste sticking to the squeegee edge is removed by the squeegee cleaning part 7, the through hole of a finished product is filled with the paste. Thus the paste is prevented from remaining over the through hole and thereby, obtain the circuit board of high quality. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing plate used for filling a paste pattern or a through hole used for a double-sided or multilayer wiring board used in various electronic devices, and a printing method using the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the miniaturization and high density of electronic devices, there has been a strong demand for multilayered circuit boards not only for industrial use but also for consumer use.
[0003]
In such a circuit board, it is essential to newly develop a connection method for connecting inner circuit holes between a plurality of layers of circuit patterns and a highly reliable structure. A high-density circuit board manufacturing method with a configuration has been proposed.
[0004]
Hereinafter, a conventional method for manufacturing a double-sided circuit board will be described.
[0005]
7 (a) to 7 (f) are sectional views showing steps of a conventional method for manufacturing a circuit board, FIG. 8 is a perspective view showing a plate frame to which a mask having an opening of a conventional example is attached, and FIG. 10 (a) to 10 (g) are cross-sectional views of a paste filling process using a squeezing method, and FIG. 11 is a cross-sectional view of a plate filling process using a conventional circuit board. It is a fragmentary sectional view.
[0006]
In FIG. 7, reference numeral 21 denotes a prepreg sheet having a size of 300 mm × 500 mm and a thickness of about 150 μm. For example, a base material made of a composite material in which a wholly aromatic polyamide fiber of a nonwoven fabric is impregnated with a thermosetting epoxy resin is used. Reference numerals 22a and 22b denote mask films, which are plastic films, for example, polyethylene terephthalate having a thickness of about 16 μm and a width of 300 mm in which a Si-based release layer portion having a thickness of 0.01 μm or less is formed on a surface to be bonded to the prepreg sheet 21. .
[0007]
For laminating the prepreg sheet 21 and the mask films 22a and 22b, a method has been proposed in which a resin component of the prepreg sheet 21 is melted by using a laminating apparatus to continuously bond the mask films 22a and 22b. Reference numeral 23 denotes a through hole, which is filled with a conductive paste 24 that is electrically connected to metal foils 25a and 25b such as copper having a thickness of 35 μm to be attached to both surfaces of the prepreg sheet 21.
[0008]
In the manufacture of the circuit board, first, as shown in FIG. 7B, a laser processing method or the like is used at a predetermined portion of a prepreg sheet 21 (FIG. 7A) having mask films 22a and 22b adhered to both sides. Thus, a through hole 23 is formed.
[0009]
Next, as shown in FIG. 7C, the conductive paste 24 is filled in the through holes 23. As a method of filling the conductive paste 24, a prepreg sheet 21 having a through hole 23 is placed on a stage 6 of a general printing machine (not shown), and two squeegees such as urethane rubber are alternately used. By reciprocating, the conductive paste 24 is directly filled from above the mask film 22a. At this time, the mask films 22a and 22b on the upper surface play a role of a printing mask and a role of preventing contamination of the surface of the prepreg sheet 21.
[0010]
The method of filling the conductive paste 24 will be further described with reference to FIGS. 8, 9, and 10A to 10G.
[0011]
The squeezing method is used for filling the conductive paste 24. However, since the prepreg sheet 21 has dedicated mask films 22a and 22b, the filling plate is filled as shown in FIGS. A stainless steel mask 2 having a thickness of about 3 mm provided with an opening 4 of 250 mm × 450 mm larger than the effective area of the prepreg sheet 21 for filling the paste is attached to the ten plate frames 1.
[0012]
First, as shown in FIG. 10A, the conductive paste 24 is filled with a prepreg sheet in which a mask film is adhered to both sides mounted on a stage 6 of a printing machine (not shown) and a through-hole 23 is formed. The mask 2 is set at 21.
[0013]
Next, only the forward squeegee 8a of the forward squeegee 8a and the backward squeegee 8b provided above and movable and pressurized vertically is lowered to a predetermined position on the mask 2, and a pressure is applied to the conductive squeegee 8a. The paste 24 is advanced while rolling.
[0014]
Next, as shown in FIG. 10B, the light passes through the opening edge 5 b of the mask 2 and reaches the prepreg sheet 21. The reciprocating squeegees 8a and 8b have a function of freely moving up and down according to the position while maintaining the pressure.
[0015]
Next, as shown in FIG. 10C, the forward squeegee 8a passes over the prepreg sheet 21 and the inclined portion of the mask 2 again, stops at a fixed position on the mask 2, and then rises to form the conductive paste 24. Is falling naturally.
[0016]
Next, as shown in FIG. 10D, only the return side squeegee 8b is lowered to a predetermined position on the mask 2. Thereafter, as shown in FIGS. 10E to 10G, the back side squeegee 8b is passed over the mask 2 and the prepreg sheet 21 in the same manner as the forward side squeegee 8a, thereby filling the through-hole 23 with the conductive paste 24. Complete.
[0017]
Then, as shown in FIG. 7D, the mask films 22a and 22b are peeled off from both surfaces of the prepreg sheet 21.
[0018]
Next, as shown in FIG. 7 (e), metal foils 25 a and 25 b such as copper are superimposed on both surfaces of the prepreg sheet 21.
[0019]
By heating and pressing with a hot press in this state, as shown in FIG. 7F, the thickness of the prepreg sheet 21 is compressed (t2 = about 100 μm) and the prepreg sheet 21 and the metal foils 25a and 25b are bonded. The metal foils 25a and 25b on both sides are electrically connected by a conductive paste 24 filling a through hole 23 provided at a predetermined position.
[0020]
Then, the metal foils 25a and 25b on both sides are selectively etched to form a circuit pattern (not shown), thereby obtaining a circuit board on both sides.
[0021]
As prior art document information related to the invention of this application, for example, Patent Document 1 and Patent Document 2 are known.
[0022]
[Patent Document 1]
JP-A-6-268345 [Patent Document 2]
JP-A-7-106760
[Problems to be solved by the invention]
However, the problem in the above-mentioned conventional paste filling method is shown in FIG.
[0024]
That is, (when the viscosity of the conductive paste 24 is high), when printing is started, when the opening edge 5b of the mask 2 is lowered, the conductive paste 24 is pressed against the surface of the prepreg sheet 21 and, thereby, around the edge of the squeegee 8b. Is extruded, and the high-viscosity conductive paste 24 adheres to the entire edge of the squeegee 8b.
[0025]
When the adhered conductive paste 24 passes through the through-hole 23 formed in the prepreg sheet 21, a hard paste remains on the through-hole 23 at the beginning of the squeegee traveling direction, especially over the entire paste filling width of the squeegee 8 b. When the mask films 22a and 22b are peeled off, a part of the conductive paste 24 may be transferred to the mask film 22a side to affect the quality.
[0026]
[Means for Solving the Problems]
In order to achieve the above object, a printing plate or a circuit board of the present invention and a paste filling method using the same include a squeegee cleaning unit provided on a printing plate before a squeegee passes through a through hole of a product. The high-viscosity paste on the squeegee edge is removed by passing the squeegee edge, and a high-quality circuit board can be obtained.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 of the present invention has a frame-shaped opening that covers the entire circumference or a part of the outer circumference of the substrate material, and has a metal sheet at the front end of the inclined portion and the other two sides. It is a printing plate fixed and fixed by protruding, and by providing a convex portion at a predetermined position on the upper surface of the protruding portion of at least one metal sheet of the inclined portion, the high viscosity paste of the squeegee edge portion formed by the inclined portion is removed. It can be removed, leaving no hard paste residue in the through-hole of the product, and eliminating the possibility that when peeling off the mask film, part of the paste will be transferred to the mask film side and adversely affect the quality. And a printing plate for performing a printing method with high paste filling quality.
[0028]
The invention according to claim 2 of the present invention is the printing plate according to claim 1, wherein the protrusions of the metal sheet are formed of linear protrusions having a predetermined length, without leaving a paste attached to the entire squeegee, It can be removed efficiently.
[0029]
According to the third and fourth aspects of the present invention, the convex portion of the metal sheet comprises a staggered convex portion having a predetermined length, and this configuration can efficiently remove the paste attached to the squeegee. It is. Further, the projections are provided at successively overlapping intervals, so that the paste adhered to the entire squeegee can be removed without leaving.
[0030]
According to a fifth aspect of the present invention, there is provided the printing plate according to the first aspect, wherein the metal sheet is etched to form the projections, and even the projections provided in a staggered manner are easily formed. Is what you can do.
[0031]
According to the invention described in claim 6 of the present invention, the convex portion of the metal sheet can be easily formed at low cost by using a molding method.
[0032]
According to a seventh aspect of the present invention, there is provided the printing plate according to the first aspect, wherein the height of the convex portion is 3 μm or more and 40 μm or less, and the squeegee edge is efficiently removed from the paste attached to the squeegee. It does not damage the.
[0033]
The invention according to claim 8 of the present invention is the printing plate according to claim 1, wherein the inclined portion has an inclination of 15 °, and facilitates passage of a squeegee.
[0034]
According to a ninth aspect of the present invention, there is provided the printing plate according to the first aspect, wherein the edges of the convex portions are rounded, and prevent damage to the squeegee edge.
[0035]
According to a tenth aspect of the present invention, there is provided a method for printing a paste on a printing material by reciprocating a squeegee using the printing plate according to the first aspect, wherein the printing plate has convex portions before printing. This is a printing method that removes the paste adhered to the squeegee edge by removing the high-viscosity paste at the squeegee edge formed by the inclined portion, eliminating the hard paste residue in the through-hole of the product, and removing the mask film. The present invention has an effect of eliminating a possibility that a part of the paste is transferred to the mask film side when peeling off and adversely affects the quality, and provides a printing method with high paste filling quality.
[0036]
The invention according to claim 11 of the present invention is the printing method according to claim 10, wherein the squeegee is stopped for a predetermined time in front of the convex portion of the printing plate. Can be removed.
[0037]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0038]
(Embodiment 1)
The paste filling method and the filling plate will be described below.
[0039]
FIG. 1 is a plan view of the printing plate of the present invention, and FIG. 2 is a cross-sectional view of the printing plate of the present invention.
[0040]
3 (a) to 3 (c) show a first metal sheet of the present invention. FIG. 3 (a) is a plan view thereof, and FIGS. 3 (b) and 3 (c) are sectional views thereof. .
[0041]
4 (a) to 4 (c) show a second metal sheet of the present invention. FIG. 4 (a) is a plan view thereof, FIG. 4 (b) is a sectional view thereof, and FIG. 4 (c) is an enlarged plan view thereof. FIG. FIG. 5 is a cross-sectional view of a step of filling a paste by the squeezing method of the present invention, and FIG. 6 is a partial cross-sectional view of filling a paste using the printing plate of the present invention.
[0042]
Note that the same components and parts described in the related art are assigned the same reference numerals, and detailed description is omitted.
[0043]
As shown in FIGS. 1 and 2, the printing plate of the present invention has a plate frame 1 made of a stainless steel mask 2 having a thickness of about 3 mm and an opening 4 of 250 mm × 450 mm wider than the paste filling area of the prepreg sheet 21. (Note that a dedicated mask film is disposed on the prepreg sheet 21 having a size of 300 × 500 mm and a thickness of about 150 μm).
[0044]
In the squeegee advancing direction (450 mm side) of the opening 4 of the mask 2, an inclined portion 5 having a 15 ° inclination is provided to facilitate passage of the squeegee.
[0045]
A metal sheet 3 fixed with an adhesive or the like protrudes about 5 mm from the back surface of the inclined portion 5 on the two sides of the mask 2 and the back surface of the other two sides.
[0046]
As shown in FIGS. 3 (a) to 3 (c), at a predetermined position on the upper surface of the metal sheet 3 having a thickness of about 100 μm which protrudes from the back surface of the inclined portion 5 of the mask 2, a convex part of about 40 μm on a straight line, As shown in FIGS. 4 (a) to 4 (c), a squeegee cleaning section 7 is formed in which protrusions having a diameter of about 300 μm and a pitch of 500 μm and a height of about 40 μm are arranged in a staggered manner at intervals of 500 μm.
[0047]
Although the height of the convex portion was set to 40 μm in the embodiment, it has been confirmed that the same effect can be obtained if the height is 3 μm or more. A height of 40 μm or less that does not damage the squeegee edge is desirable.
[0048]
The projections on the straight line were formed by etching or molding, and the staggered projections were formed by etching.
[0049]
In order to prevent damage to the squeegee edge, the edge of the convex portion is preferably rounded using an etching method or the like.
[0050]
In particular, when the protrusions are formed in a staggered manner, it is preferable that the formed protrusions are arranged so that the respective protrusions are flush with each other or overlap as shown in FIG. Further, in the embodiment, the squeegee cleaning portion 7 is formed only by the convex portion, but a through hole or a non-through hole may be provided in the convex portion.
[0051]
A method for filling the conductive paste will be briefly described with reference to FIGS.
[0052]
First, as shown in FIG. 5A, the mask films 22a and 22b are adhered to both sides of the conductive paste 24 placed on the stage 6 of a printing machine (not shown) to form the through holes 23. The mask 2 is set on the prepreg sheet 21.
[0053]
Then, only the forward squeegee 8a of the forward squeegee 8a and the backward squeegee 8b provided above and movable and pressurized up and down, left and right is lowered to a predetermined position on the mask 2, and the pressure is applied to the conductive paste. 24 is moving forward while rolling.
[0054]
Then, as shown in FIG. 5B, the light passes through the inclined portion 5 of the mask 2 and reaches the prepreg sheet 21. The reciprocating squeegees 8a and 8b have a function of freely moving up and down according to the position while maintaining the pressure.
[0055]
Then, as shown in FIG. 5C, the forward squeegee 8a passes over the prepreg sheet 21 and the inclined portion 5 of the mask 2 again, stops at a fixed position on the mask 2, and then rises to remove the conductive paste 24. Let it fall naturally.
[0056]
Next, as shown in FIG. 5D, only the return side squeegee 8b is lowered to a predetermined position on the mask 2.
[0057]
Then, as shown in FIGS. 5 (e) to 5 (g), the rear side squeegee 8b is passed over the mask 2 and the prepreg sheet 21 in the same manner as the forward side squeegee 8a, so that the conductive paste 24 is filled into the through holes 23. Complete. In the printing plate of the present invention, a metal sheet 3 having a squeegee cleaning portion 7 formed by a convex portion at a predetermined position on the upper surface is projected from the back surface of the inclined portion 5 of the mask 2 on the start side of the return side squeegee 8b.
[0058]
FIG. 6 is a partial cross-sectional view when the backward squeegee 8b starts and passes through the mask 2, the inclined portion 5, the squeegee cleaning portion 7 on the metal sheet 3, and the through hole 23 in the product.
[0059]
As a result, after the refilling squeegee 8b starts to be filled, when the squeegee cleaning unit 7 passes through the squeegee cleaning unit 7 via the inclined unit 5 of the mask 2, the squeegee cleaning unit 7 removes the convex edge on the inclined unit 5 side of the mask 2. It was confirmed that the conductive paste 24 remained.
[0060]
The distance from the inclined portion 5 of the mask 2 to the squeegee cleaning portion 7 is set to a distance that allows the deformation of the squeegee 8b to be restored when the inclined portion 5 is lowered, or the speed of the squeegee 8b is reduced or temporarily stopped. It is advisable to fill at a normal speed after the deformation is restored.
[0061]
In the present embodiment, the squeegee 8b is filled before stopping the squeegee cleaning unit 7 for about 1 second.
[0062]
Then, the conductive paste 24 remaining in the squeegee cleaning unit 7 was removed by the forward squeegee 8a when the next prepreg sheet 21 was filled, and it was confirmed that the effect was continuously effective.
[0063]
Further, 100 prepreg sheets 21 in which the conductive paste 24 was filled in the through holes were confirmed. However, after passing through the squeegee cleaning unit 7, no paste remained on the through holes, and the mask films 22a and 22b were peeled off when the mask films 22a and 22b were peeled off. , 22b were not transferred and did not affect the quality.
[0064]
【The invention's effect】
As described above, the printing plate and the printing method of the present invention provide a product by removing a high-viscosity paste at a squeegee edge at a squeegee cleaning unit provided on a printing plate before filling a paste into a through hole of a circuit board. It is possible to prevent a high-viscosity paste residue on the through-hole, and to provide a circuit board having excellent quality.
[Brief description of the drawings]
FIG. 1 is a plan view of a printing plate of the present invention. FIG. 2 is a cross-sectional view of the printing plate of the present invention. FIGS. 3A to 3C each show a first metal sheet of the present invention. FIGS. 4 (a) to 4 (c) each show a second metal sheet of the present invention. FIGS. 5 (a) to 5 (g) are cross-sectional views of steps of paste filling by the squeezing method of the present invention, respectively. FIG. 6 is a partial cross-sectional view when filling a paste using the printing plate of the present invention. FIGS. 7A to 7F are process cross-sectional views of a conventional method for manufacturing a double-sided circuit board, respectively. FIG. 9 is a perspective view showing a plate frame to which a conventional mask having an opening is mounted. FIG. 9 is a cross-sectional view of a plate frame to which a conventional mask having an opening is mounted. FIG. 11 is a cross-sectional view of a paste filling process using a conventional squeezing method. Part sectional view EXPLANATION OF REFERENCE NUMERALS
Reference Signs List 1 plate frame 2 mask 3 metal sheet 4 opening 5 inclined section 6 stage 7 squeegee cleaning section 8a forward squeegee 8b return side squeegee 21 prepreg sheets 22a, 22b mask film 23 through hole 24 conductive paste 25a, 25b metal foil

Claims (11)

A mask having a frame-shaped opening covering the entire periphery or a part of the outer periphery of the substrate material, and having a slope provided above two sides of the opening in the squeegee traveling direction is fixed to at least four sides of the frame. A printing plate comprising a metal sheet protruding and fixing a predetermined amount to the rear end of the inclined portion and the other two sides, and a printing plate provided with a convex portion on at least the upper surface of the protruding portion of one of the inclined metal sheets. . The printing plate according to claim 1, wherein the convex portion of the metal sheet comprises a linear convex portion having a predetermined length. The printing plate according to claim 1, wherein the protrusions of the metal sheet are formed in a staggered manner with a predetermined length. 4. The printing plate according to claim 3, wherein the protruding portions provided in a zigzag pattern on the metal sheet are provided at intervals such that they sequentially overlap. The printing plate according to claim 1, wherein the convex portion is formed by etching the metal sheet. The printing plate according to claim 1, wherein the metal sheet is molded to form the convex portion. The printing plate according to claim 1, wherein the height of the protrusion is 3 μm or more and 40 μm or less. The printing plate according to claim 1, wherein the inclined portion has an inclination of 15 °. The printing plate according to claim 1, wherein an edge of the projection is rounded. A method of printing a paste on a printing material by reciprocating a squeegee using the printing plate according to claim 1, wherein the printing method removes the paste attached to the squeegee edge at a convex portion of the printing plate before printing. . The printing method according to claim 10, wherein the squeegee is stopped for a predetermined time before the convex portion of the printing plate.

Images