JPS62237793A - Manufacture of printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for manufacturing a printed wiring board, and more specifically, to a method for manufacturing a printed wiring board, and more specifically, to a method for producing a printed wiring board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for producing a printed circuit board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for manufacturing a printed wiring board, and more specifically, a method for producing a printed wiring board, and more specifically, a method for manufacturing a printed circuit board. The present invention relates to a method for efficiently manufacturing a wiring board through a simple process.

<Conventional technology> Conventionally, methods for manufacturing printed wiring boards include a method in which a circuit pattern is formed using etching on a base material such as glass epoxy or phenol to which copper foil is pasted (subtract method), and an electroless method. A method of forming a circuit pattern on a base material using plating or electrolytic plating (additive method), a method of forming a circuit pattern on a base material using screen printing using conductive ink or insulating ink (screen printing) However, other manufacturing methods include forming a circuit pattern on a base material using the transfer printing method, which is commonly used to decorate decorative items (transfer printing method).
is publicly known (for example, Japanese Patent Application Laid-Open No. 1989-1999 proposed by the present applicant).
(Refer to the invention described in JP-A-121791).

In this transfer printing method, a transfer material for a printed wiring board having a desired circuit pattern is prepared by screen printing using conductive ink or insulating ink on a base sheet that has releasability in advance, and this transfer This is a method in which the circuit pattern is transferred onto the surface of the printed wiring board base material simultaneously with the molding of the printed wiring board base material or after the printed wiring board base material is molded.

According to this transfer printing method, a printed wiring board can be efficiently manufactured in a simple process, and when transfer printing is performed at the same time as forming a base material for a printed wiring board, a printed wiring board exhibiting a three-dimensional shape can be produced. can also be easily and efficiently produced.

<Problems to be Solved by the Invention> However, the printed wiring board obtained by this transfer printing method has problems with the stability of soldering in the land portion made of polymer-type ink provided on the surface for mounting components. There was a problem that it was missing.

As a result of various research and considerations regarding the cause of this, the present inventors found that the surface of the land portion obtained by the transfer printing method is
Compared to the land area obtained by conventional screen printing, the resin component used as a binder for the conductive ink is richer, and the active ingredients necessary for soldering are significantly lacking. I found out. This means that when screen printing conductive ink or insulating ink on a releasable base sheet, stable soldering is not possible even if a polymer ink with releasable properties is used, the base sheet and circuit pattern are The gas contained in the bubbles generated at the interface expands when the ink hardens and is released to the outside, and the resin component used as the binder for the ink flows into this gap, causing the resin component to become rich at the interface. hardens in the state. This is thought to be because when this transfer material is used for transfer printing on the surface of a substrate for a printed wiring board, the surface of the land portion becomes covered with a resin component that inhibits soldering (see FIG. 4).

<Means for Solving the Problems> Based on the above-mentioned knowledge, the inventors of the present invention have conducted further research and consideration, and have devised a method to remove unnecessary resin components by polishing the land portion obtained by the transfer printing method. Specifically, the inventors have discovered that the above-mentioned problems can be solved, and have completed the present invention. That is, the present invention uses a transfer material in which a circuit pattern layer made of conductive ink or insulating ink is provided on a base sheet, performs transfer printing on a base material for a printed wiring board, and then transfers the base sheet. Manufacture of a printed wiring board, characterized in that unnecessary resin components on the land portions are removed by polishing at least the land portions used for component mounting on the surface of the base material that has been peeled off and then subjected to transfer printing. It is the law.

Hereinafter, the present invention will be explained in more detail using the drawings. Note that the drawings are drawn in an exaggerated manner, ignoring the relative dimensional relationships of the constituent elements, for clarity of illustration.

First, the transfer material used in the present invention will be explained. Second
Referring to the figure, 1 is a base sheet having mold releasability, 3 is a circuit pattern layer, and the circuit pattern layer 3 is composed of a conductive pattern layer 4 and an insulating layer 11i5. 6 is adhesive layer, L
is a land portion, and S is a through-hole portion.

The base sheet 1 having mold releasability includes polyester, polyimide, polyallyl sulfone, polyether ether ketone, polyphenylene sulfide, and polyester having heat resistance.
Single or composite films of polymethylpentene, polyethylene, polypropylene, etc. may be used. If necessary, it is preferable to use a material that has been subjected to mold release treatment such as silicon treatment.

The conductive pattern layer 4 is formed into a desired pattern by printing S conductive ink. As the binder for the conductive ink, thermoplastic resins such as heat-resistant polyethersulfone or polysulfone, polyetherimide, polyamideimide, polyallylsulfone, polyarylate, polyphenylene oxide, polyphenylene sulfone, polycarbonate, and polyamide; Alternatively, use a hardening resin such as epoxy, phenol, polyester, or acrylic. As the conductive powder of the conductive ink, a metal or an inorganic conductive powder such as silver, aluminum, copper, nickel, gold, carbon, graphite, or one coated with a metal on the surface of glass beads is used. A conductive ink is prepared by selecting an appropriate solvent and uniformly mixing the binder and conductive powder.

This conductive ink may contain a certain amount of surfactant, additives, etc. to improve its performance as a printing ink.

The insulating layer 5 is formed on the entire surface or in a pattern by printing or coating with insulating ink. As for the binder of the insulating ink, as in the conductive pattern layer 4, thermoplastics such as polyethersulfone or polysulfone, polyetherimide, polyamideimide, polyallylsulfone, polyarylate, polyphenylene oxide, polyphenylene sulfone, polycarbonate, polyamide, etc. Use resin or hardening resin such as epoxy, phenol, polyester, or acrylic.

Further, an insulating powder is used as an insulating ink if necessary. An insulating ink is prepared by selecting an appropriate solvent and uniformly mixing the binder and insulating powder. As the insulating powder, inorganic powders such as dichromium oxide, alumina, silicon dioxide, zirconium oxide, magnesium oxide, beryllium oxide, boron nitride, mica, magnesium silicate, and steatite can be used. This insulating ink may contain a small amount of surfactant, hydrating agent, etc. to improve its performance as a printing ink.

Note that for the circuit pattern layer 3 consisting of the conductive pattern N4 and the insulating layer 5, a heat-resistant thermoplastic resin with a thermal deformation onset temperature of 120° C. or higher or a thermosetting resin containing unreacted groups is used as a binder. When formed using conductive ink and/or insulating ink, a printed wiring board with excellent heat resistance can be obtained.

The adhesive layer 6 connects the circuit pattern layer 3 to the substrate 7 for printed wiring board.
This is a layer for adhering to. For example, the main component of the adhesive layer 6 formed to cover the circuit pattern layer 3 is 120
It is preferable to use a printing method or a coating method to form a thermoplastic resin that starts to undergo thermal deformation at a temperature of 130° C. to 130° C., preferably 150 to 250° C. This is because when the molten injection molding resin comes into contact with the adhesive layer 6 of the transfer material, the adhesive layer 6 softens slightly without melting, thereby making the bond stronger. Examples of such thermoplastic resins include polysulfone, polyethersulfone, polyetherimide, polyimideamide, polyallylsulfone, polyarylate, polyphenylene oxide, polyphenylene sulfone, polycarbonate, polyamide, and the like. Furthermore, a thermosetting resin having an unreacted group may be used instead of the thermoplastic resin.

This adhesive layer 6 may be omitted depending on the material forming the circuit pattern N3.

In addition, a through hole S portion is formed in the insulating layer 5 between the conductive pattern layers 4, if necessary, for making the conductive pattern layers 4 conductive to each other.

In addition to the transfer material shown in FIG. 2, various forms of the transfer material according to the present invention can be used depending on the required circuit pattern. For example, a full-surface release layer 2 may be provided on the base sheet 1, and a circuit pattern layer 3 may be provided thereon (see FIG. 3).

Next, the manufacturing process of the printed wiring board according to the present invention will be explained.

First, a transfer printing process is performed on the surface of the printed wiring board base material 7 using a transfer material having the above-described structure. As a method of transfer printing processing, a pre-formed printed wiring board base material 7 is used.
A method in which a transfer material is placed on the surface of the printed circuit board and heated and pressurized.When molding the base material 7 for printed wiring board, the transfer material is placed inside the mold for molding, and the base material 7 is molded. At the same time, the base material 7
There are methods such as transfer printing on the surface.

After transfer printing, unnecessary resin components are removed from at least the land portions on the surface of the printed wiring board 8 from which the base sheet 1 has been peeled off. Methods for removing it include polishing with sandpaper, a sandbrush, or a puff.

By doing this, in the land portion used for component mounting provided on the surface of the printed wiring board 8,
The conductive powder component is exposed on the surface (see Figure 5).

<Example> On a 38 μm thick polyethylene terephthalate film that has been treated with charcoal silicone mold release treatment, a pattern is created only in the areas that require soldering using silver paste (using an epoxy binder).
or copper paste (with thermosetting phenolic binder)
A transfer material for a printed wiring board was prepared by printing an insulating ink having the composition shown below on the parts not requiring soldering, and performing heat treatment.

Composition 1 (wt%) Polysulfone 30 Aerosil (manufactured by Nippon Aerosil Co., Ltd.) 5 Solvent (cyclohexanone; butyl cellosolve acetate) 65 This transfer material was aligned and placed in an injection mold, the mold was closed, and polyether sulfone resin was added. Injection was carried out under the following conditions.

Injection conditions (Japan Steel Required JC150SA) Mold temperature
100~120℃ cylinder temperature
350~380℃ injection pressure
99% holding force 70
~73% injection speed 99% screw rotation speed 5Orpm Then,
After the resin had solidified, the mold was opened, the molded product was taken out, and the base sheet was peeled off, resulting in a print 11 wiring board on which two conductive pattern layers were formed, with no pattern melting and strong adhesion. Ta.

After this, the surface of the land part and the insulating layer was polished with a sandbrush, and soldering was carried out using the solder dip method at 260°C for 3 seconds. As a result, the silver and copper paste parts of the land part were stably soldered. was applied evenly, and no blistering or decrease in adhesive strength due to heat occurred on other parts.

A release ink (polyester binder) is printed on the entire surface by screen printing on a 38 μm thick polyethylene terephthalate film that has been released by coating with epoxy resin, and then copper paste (thermosetting phenol) is applied. A transfer material for printed wiring boards was created by screen-printing an insulating paste of epoxy resin to be used as an insulating layer and an adhesive layer, and then heat-treating the paste (using a binder) (using a binder). (See Figure 3).

The epoxy resin at this time leaves unreacted group components.

A molded product was produced using this transfer material in the same manner as in Example 1, and then heat treated to obtain a printed wiring board on which a circuit pattern layer with strong adhesion was formed.

After this, the surface of the land part and the insulating layer was polished with a sandbrush, and soldering was performed using the solder dip method at 260°C for 3 seconds. was applied evenly, and no blistering or decrease in adhesive strength due to heat occurred on other parts.

<Effects of the Invention> Since the present invention has the above configuration,
It is possible to easily and efficiently produce a printed wiring board with excellent soldering stability in land portions made of polymer-type ink.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a printed wiring board according to the present invention, FIG. 2 is a cross-sectional view showing an example of a transfer material used in the present invention, and FIG. 3 is a cross-sectional view showing an example of a transfer material used in the present invention. A sectional view showing another embodiment, FIG. 4 is a plan view showing the surface condition of the land portion in a conventional printed wiring board, and FIG. 5 is a plan view showing the surface condition of the land portion in the printed wiring board according to the present invention. It is. 1...Base sheet, 2...Peeling layer, 3...
Circuit pattern layer, 4... Conductive pattern layer, 5...
- Insulating layer, 6... Adhesive layer, 7... Base material for printed wiring board, 8... Printed wiring board, 9... Conductive powder, 1O... Resin component, L... Land Part, S...Through hole part. Patent applicant Nissha Printing Co., Ltd. L L L Figure 2 Figure 3 Figure 4 Figure 3

Claims (1)

[Claims] (1) Using a transfer material in which a circuit pattern layer made of conductive ink or insulating ink is provided on a base sheet,
Transfer printing is applied to a base material for a printed wiring board, the base sheet is then peeled off, and after that, at least the land portion used for mounting components on the surface of the base material on which transfer printing has been applied is polished, thereby eliminating the need for the surface of the land portion. A method for manufacturing a printed wiring board characterized by removing resin components.