JP3529240B2 - Screen plate manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a screen printing plate, and more particularly to a method of manufacturing a screen printing plate for bump formation suitable for printing and forming a conical bump.

[0002]

2. Description of the Related Art For example, as an application of a conductive paste, formation of a wiring pattern such as a wiring board, or a structure of an electrically connecting portion between wiring pattern layers is known. That is, in the manufacture of a multilayer wiring board, it has been attempted to make electrical connection (through hole connection) between wiring pattern layers that are integrally arranged via an insulating layer by embedding a conductive paste. More specifically, a hole penetrating (inserting) through the insulating layer is formed at an electrical connection point between the wiring pattern layers, and a conductive plating layer is grown on the inner wall surface of the hole to form a required layer. It is known that instead of forming the through-hole connection, a conductive paste is filled and embedded in the hole to form a required through-hole connection.

The means for forming the through-hole connection has a problem that it is difficult to form holes with high accuracy as the wiring pattern becomes denser (or finer), and the insulating layer is used. There is a tendency that the process of forming a hole that penetrates (inserts) becomes significantly complicated. In addition, when the diameter of the through hole forming the through-hole connection is reduced, it is difficult to uniformly grow the plating layer and it is difficult to densely fill / embed the conductive paste, and thus the through-hole connection is formed. There is a problem with the reliability of.

Further, for example, a thermoplastic resin sheet is used as an insulating layer between the wiring pattern layers, while conductive bumps are previously installed at predetermined positions of the wiring pattern, and they are laminated and integrated in the process. Attempts have also been made to form through-hole connections by utilizing the fact that the conductive bumps penetrate the insulating layer.

[0005]

For example, when the conductive bump method is used in the manufacture of a multilayer wiring board,
Much attention is being paid to practical use because it is possible to avoid complicated operations such as management of plating liquid and post-treatment as in the case of forming through-hole connection by plating. In particular,
Conductive bumps are screen-printed and arranged in advance, and the insulating layer is pierced (inserted) in the pressure process of laminating and integrating with the insulating layer, and the tip end of the inserted conductive bump is opposed to the wiring. The means for electrically connecting to the pattern is noted from the viewpoints that it is possible to form a high-density wiring board, and that productivity and yield are good. By the way, a screen plate manufactured as follows is generally used for forming the conductive bumps.

(A) Through holes are formed by chemical etching (treatment) at predetermined positions on both main surfaces of a stainless steel plate or a phosphor bronze plate having a thickness of about 0.1 to 2 mm to form a screen plate.

The screen plate is formed by forming a through hole by processing.

(B) A screen plate is formed by forming a through hole by drilling at a predetermined position of a stainless steel plate or a phosphor bronze plate having a thickness of about 0.3 to 2 mm.

However, in the multilayer wiring board,
Furthermore, the caliber is as small as 0.1 mm and the dimensions are highly accurate.
Shaped conductive bumps are required, and when trying to obtain a screen plate with an opening with an aspect ratio of about 1 on a stainless steel plate with a thickness of 0.1 mm, there are the following problems, and improvements are desired. It is rare.

First, in the case of (a), as shown schematically in FIGS. 4 (a) to 4 (c), a resist layer 2 is provided on both sides of a stainless steel plate 1 (see FIG. a)),
This resist layer 2 is patterned (FIG. 4 (b)). After that, as etching progresses from both sides, Fig. 4 (c)
As shown in the enlarged view of FIG. 1, the cross-sectional shape of the formed through hole 3 has a problem that the central portion diameter is small. That is,
There is a problem that the cross-sectional shapes of the through holes 3 become uneven, which makes it difficult to perform screen printing with high accuracy in terms of size and shape, and burrs are generated on the inner wall surface of the holes 3 to easily damage the screen plate. .

Further, in the case of (b), it is generally desired that the thickness of a stainless steel plate or the like is at least about 0.3 mm in view of compatibility with drilling, and that the aperture ratio is 0.15 to 0.1 mm and the aspect ratio is about 1. It can be said that it is practically difficult to form a through hole. In other words, it can be said that the drilling method is generally unsuitable for the production of a screen plate for forming bumps with a small diameter of about 0.1 mm and highly accurate size and shape.

The present invention has been made in view of the above circumstances, and it is a screen printing plate capable of printing and forming bumps or the like having an opening diameter as small as 0.15 mm at the most and having high dimensional and shape accuracy.
An object of the present invention is to provide a manufacturing method of.

[0013]

The invention according to claim 1 is a resin
A rigid first metal layer and a second rigid metal layer through the adhesive layer of the system.
A first metal layer of a laminated thin plate formed by laminating and integrating metal layers
Opening register with a relatively large diameter that opens in the thickness direction on the surface
And a step of patterning the second metal layer.
The central axes of the holes that open in the
A step of patterning a resist for a small opening;
Etching processing on laminated thin plates that have been patterned
The adhesive layer as a stop line on both metal layers.
A step of forming a fixed opening, and a bottom wall surface of the formed opening
And removing the adhesive layer forming
This is a method for producing a characteristic screen plate .

According to a second aspect of the present invention, a resin-based adhesive layer is interposed.
And rigid first metal layer and second metal layer are laminated and integrated
Open in the thickness direction on the first metal layer surface of the laminated thin plate
Resist patterning for openings with relatively large diameter
And a resist layer is provided on the surface of the second metal layer.
Etching the laminated thin plate with the process and the resist layer
Is applied to the first metal layer using the adhesive layer as a stop line.
A step of forming a predetermined opening in the
Align the central axes of the holes to make a small-diameter opening in the second metal layer.
And a step of drilling with a drill.
This is a lean plate manufacturing method .

These allow the paste to pass through and
It is a screen version with an opening that forms a bump.
The screen plate is made of a rigid first metal layer, a resin-based material.
The adhesive layer and the second metal layer, and
Opening the adhesive layer and the second metal layer to the openings in the metal layer.
A screen plate with a reduced mouth is obtained .

Alternatively , in this screen version, the page
The openings through which the strike passes are the first metal layer portion and the second metal
It is possible to obtain things by reducing the diameter stepwise in layers .

That is, the present invention relates to a screen plate for selectively passing a conductive paste to form fine conductive bumps, for example, with an adhesive resin layer interposed on the contact / joining surface, This resin layer is used as a stopper for selective etching, and by piercing minute diameter holes that present a sharp inner wall surface, we are aiming to provide a screen plate that can form highly accurate conductive bumps with a minute diameter and shape. It is a thing.

According to the method of manufacturing a screen plate according to the present invention
The screen plate produced by
A stainless steel plate, phosphor bronze plate, brass plate, nickel alloy plate, plated steel plate or the like having a rigidity of about 1 m, which has a thickness of, for example, 10
The machine body is composed of a laminated thin plate made by laminating a second metal layer such as copper foil or stainless steel foil of about 100 μm. Then, the perforation with a small diameter is performed by, for example, selective etching treatment or a combination of selective etching treatment and drilling. Here, since the thickness of the first metal layer is set to be relatively thick in consideration of mechanical strength and easiness of handling, an opening having a large diameter is formed in order to secure a good aspect ratio. Drilled. On the other hand, the second metal layer has a relatively small thickness and is formed with minute openings having a good aspect ratio, and the second metal layer side supported by the first metal layer is substantially a screen. Serves as a plate.

In the inventions of claims 1 and 2, complicated steps are involved.
It is possible to correspond to the cross-sectional shape of a minute and fine hole without requiring
However, as a whole, fine bumps with uniform shapes and dimensions
Screen plate that can easily print and form
Can be provided .

In this screen plate, the first metal layer side is
It has a relatively large diameter, and the side with the large diameter is conductive.
For squeezing with a conductive paste
Passes through the opening on the metal layer side by force to facilitate precise bumping
Is formed. In other words, the diameter of the opening (through hole) is
In this mode, the paste is discharged from a small hole such as paste under pressure.
Therefore, it is dense and corresponds to the cross-sectional shape of micropores,
Physically, it is easy to form minute bumps with uniform shapes and dimensions.
Is made.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments will be described below with reference to FIGS. 1, 2 (a), 2 (b) and 3 (a), 3 (b), 3 (c), 3 (d).

FIG. 1 is a sectional view showing an example of the essential structure of the screen plate of the first embodiment. In FIG. 1, 4
Is a rigid first metal layer such as stainless steel having a thickness of 0.15 mm, 5 is a resin adhesive layer such as epoxy resin, and 6 is a thickness
A second metal layer such as 36 μm copper foil. Here, the opening 4a of the first metal layer 4 has a diameter of about 0.2 mm, the opening 6a of the second metal layer 6 has a diameter of about 0.1 mm, and these openings 4a, 6a are
While being coaxially connected, the diameter of the adhesive layer 5 is reduced. This screen version is 500 mm long and 600 mm wide.
mm, the number of through holes is 10,000.

Next, an example of use of the screen plate 7 having the above structure will be described. The reduced-diameter opening 6a surface side of the screen plate 7 is contacted and arranged on a copper foil surface having a thickness of 18 μm which is placed substantially horizontally. After that, a conductive paste is applied and carried on the opening 4a side of the screen plate 7 and a so-called squeezing treatment is performed, and then the screen plate 7 is removed, and the conductive paste filled in the reduced-diameter opening 6a is conical. -Shaped conductive bumps are printed and carried on the copper foil surface.

Next, the printed / carried conductive bumps are dried, and if necessary, the alignment of the screen plate 7 and the printing / drying of the conductive paste are repeated to form conductive bumps of a desired height. . The shape and the like of the conductive bumps formed in this way were observed and evaluated. As a result, they were cylindrical with a height of about 0.1 mm and a diameter of 0.1 mm, and had very little variation. As the conductive paste, the thermosetting conductive paste DW-250H-5 product name (manufactured by Toyobo KK)
The silver paste and the like, which are commercially available at. A conductive bump is formed at the predetermined position, and a copper foil having a thickness of 18 μm is superposed on the copper foil surface via an epoxy resin / glass cloth prepreg layer (insulator layer) to form a laminate. After that, the laminated laminate is subjected to heat and pressure treatment at a temperature of about 160 to 180 ° C., a pressure of about 30 to 50 kg / cm ^{2 for} about 30 to 60 minutes, so that the insulating layer penetrates in the thickness direction. A double-sided copper foil-clad laminate is obtained in which the copper foils on both sides are electrically connected by the bumps.

Then, using the double-sided copper foil-clad laminate thus produced as a raw material, the double-sided copper foil was subjected to photo-etching for fine wiring patterning to produce a double-sided wiring board. In this double-sided wiring board, the required connection is reliably made by the conductive bumps, and the electrical resistance of the connection portion is low, so that a highly reliable wiring circuit is formed.

Next, an example of a method of manufacturing the screen plate 7 will be described. 2A and 2B are cross-sectional views schematically showing the first embodiment example.

First, a rigid first metal layer 4 such as stainless steel having a thickness of 0.15 mm, a second metal layer 6 such as a copper foil having a thickness of 36 μm, and a resin adhesive layer 5 such as an epoxy resin are interposed. A metal laminated plate which is laminated and integrated is prepared. Then
As shown in FIG. 2A, an etching resist pattern 8a is formed on the surface of the first metal layer 4 of the metal laminated plate, and then an etching resist pattern 8a is formed on the surface of the second metal layer 6.
Form 8b.

The etching resist pattern 8a on the surface of the first metal layer 4 has an opening 8 with a diameter of about 0.2 mm.
The etching resist pattern 8b in the second metal layer 6 has an opening 8 having a diameter of about 0.1 mm.
b ', and these openings 8a', 8b 'are coaxially opposed. The etching resist patterning is performed on the surface of the second metal layer 6 first and then first.
It may be performed on the surface of the metal layer 4.

Next, the metal laminate having the above etching resist patterning is subjected to an etching treatment. That is, the etching resist pattern is formed by immersing in a selective etching solution for the first metal layer 4 and the second metal layer 6, for example, an etching solution containing iron chloride and copper chloride.
Regions of the first metal layer 4 and the second metal layer 6 exposed corresponding to the openings 8a 'and 8b' of 8a and 8b are selectively etched. Here, as the etching liquid, it is preferable to select one having a strong etching action on the metal layer (first metal layer 4) having the larger openings 8a 'and 8b' of the resist patterns 8a and 8b.

In this etching process, the openings 8 of the etching resist patterns 8a and 8b are formed on both the first metal layer 4 side and the second metal layer 6 side as shown in FIG. 2 (b).
Corresponding to a'and 8b ', perforation is advanced in the thickness direction, and perforation is stopped by the adhesive layer 5. That is, the perforation due to the etching action is advanced in the thickness (depth) direction in the regions corresponding to the openings 8a ′ and 8b ′, and the diameter is reduced as the thickness (depth) progresses. Since the agent layer 5 suppresses the progress in the depth direction, the adhesive layer 5
Etching in the radial direction progresses in the area adjacent to
Sharp drilling with uniform inner diameter.

After the above etching process, the etching resist patterns 8a and 8b are removed, while the adhesive layer 5 that blocks the opening 4a of the first metal layer 4 and the opening 6a of the second metal layer 6 is removed. For example, by punching (punching) by a drilling process or the like, the screen plate 7 having the structure shown in FIG. 1 can be obtained. The punching of the adhesive layer 5 by punching can also be performed by means such as spraying a high-pressure gas or dissolving and removing with a solvent.

FIGS. 3A to 3D are sectional views schematically showing a second embodiment of the method for manufacturing the screen printing plate 7.

In this embodiment, a metal laminated plate (laminated thin plate) having the same structure as in the case of the first embodiment is prepared, and the first metal layer 4 is formed as shown in FIG. 3 (a). An etching resist layer 8c is provided on the surface of the second metal layer 6 while the etching resist patterning for the opening having a relatively large aperture opening in the thickness direction is formed on the surface. Then, the metal laminated plate provided with the etching resist layers 8a and 8c,
For example subjected to etching treatment was immersed in e pitch ranging solution of iron chloride, puncture as shown in FIG. 3 (b), a predetermined opening 4a to the first metal layer 4 an adhesive layer 5 as a stop line Set up.

Then, as shown in FIG. 3 (c), the etching resist layers 8a and 8c are respectively removed and then set in an NC control type drilling device, and the central axis of the drilled / opened hole 4a is set. A small-diameter opening 6a is drilled in the second metal layer 6 in accordance with the above. By this drilling process, the required opening 6a is formed in the second metal layer 6, and the adhesive layer 5 is also punched or punched to form a coaxial hole (opening) penetrating in the thickness direction. A screen plate as shown in (d) was manufactured. This screen plate is a stepped type with a hole (opening) diameter penetrating in the thickness direction that is sharp in the depth direction.
In addition, the variation with respect to the predetermined hole diameter was within ± 5%, and it was possible to pass and fill the conductive paste or the like that was substantially uniform as a whole.

That is, the screen plate (vertical 5
00mm, width 600mm, through hole number 10000) is arranged on one main surface of electrolytic copper foil for printed wiring board, and after conductive paste is screen-printed, the screen plate is removed and dried to form conductive bumps. Formed. The shape and the like of the conductive bumps formed in this way were observed and evaluated. As a result, they were cylindrical with a height of about 0.12 mm and a diameter of 0.1 mm, and had very little variation.

The present invention is not limited to the above examples, and various modifications can be made without departing from the gist of the invention, and the application is also through holes between wiring pattern layers of a printed wiring board. It can be used not only for forming bumps for connection, but also for forming electrode terminals (bumps) of electronic parts, or for general printing. Also,
The screen plate is also made of a material other than those exemplified above, and the first metal layer is, for example, a phosphor bronze plate having a thickness of about 0.1 to 0.25 mm, a brass plate, a nickel alloy plate, a plated steel plate, or the like, and a second metal layer. For example, a stainless steel foil having a thickness of about 10 to 100 μm can be used.

[0037]

According to the present invention, there is no need for complicated steps.
In addition, it is dense and corresponds to the cross-sectional shape of micropores,
In addition, it is easy to print fine bumps with uniform shapes and dimensions.
It is possible to provide a screen plate that can be printed and formed .

[0038]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main configuration of a screen plate according to an embodiment.

2A and 2B are cross-sectional views schematically showing an example of a first manufacturing process of the screen plate shown in FIG.

3 (a), (b), (c), and (d) are cross-sectional views schematically showing a second manufacturing process example of the screen plate shown in FIG.

4 (a), (b) and (c) are cross-sectional views schematically showing an example of a conventional screen plate manufacturing process.

[Explanation of symbols] 4 ... the first metal layer 4a ... Opening of the first metal layer 5 ... Adhesive layer 6 ... second metal layer 6a ... Aperture of the second metal layer 7 ... Screen version 8a, 8b, 8c ... Etching resist 8a ', 8b' ... Opening of etching resist

Continuation of the front page (56) Reference JP-A-2-34395 (JP, A) JP-A-5-229091 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41N 1 / 24 B41C 1/14

Claims (2)

(57) [Claims] 1. A comparison in which a rigid first metal layer and a second metal layer are laminated and integrated via a resin-based adhesive layer, and a laminated thin plate is opened in the thickness direction on the first metal layer surface. A step of patterning an opening resist having a large aperture, a step of aligning a central axis of the hole opened in the thickness direction with the second metal layer surface, and performing a resist patterning of an opening having a relatively small aperture, and the resist patterning A step of etching the laminated thin plate to form a predetermined opening in each of the metal layers with the adhesive layer as a stop line, and removing the adhesive layer forming the bottom wall surface of the opened opening. A method of manufacturing a screen printing plate, comprising: 2. A comparison in which a rigid first metal layer and a second metal layer are laminated and integrated through a resin-based adhesive layer, and a laminated thin plate is opened in the thickness direction on the first metal layer surface. A step of patterning a resist for an opening having a large aperture, a step of providing a resist layer on the surface of the second metal layer, an etching process is performed on the laminated thin plate provided with the resist layer, and an adhesive layer is used as a stop line. A step of drilling a predetermined opening in the first metal layer, and a step of drilling a small-diameter opening in the second metal layer by aligning the central axes of the opened holes. And a method for manufacturing a screen plate.