JPH0242789A - Manufacturing method 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 Field of Industrial Application The present invention relates to a method for manufacturing printed wiring boards used in various electronic devices. The solder resist on the conductive pattern is formed by a screen printing method, and on the copper foil there is often a soldering part where no solder resist is applied during printing.

Furthermore, in the mounting of components in electronic devices, there is a trend toward higher density and smaller land spacing and land area due to the higher density of circuits. Against this background, there is a demand for higher precision in solder resist formation.

Hereinafter, conventional solder resist formation 9 will be explained with reference to the drawings.
A method for forming a component insertion hole and a method for forming a land portion will be explained.

Fig. 6 is a cross-sectional view of the solder resist formed by a conventional method, and Fig. 6 is a cross-sectional view of the printed wiring board and the mold after punching with a conventional mold and forming component insertion holes. be. In FIGS. 5 and 6, 1 is an insulating substrate that serves as a paste for a printed wiring board, 2 is a solder resist, 3 is a copper foil land, 4 is an upper mold of the mold, 41 is a lower mold of the mold, 6 7 is the mold punch, and 7 is the abnormal coverage of the solder resist 2 on the copper foil land 3 caused by printing misalignment or bleeding (
Hereafter, this is referred to as "hakikire").

In recent printed wiring boards, as the density of circuits has increased, the distance between the copper foil lands 3 (diameter 1 component insertion hole diameter 9 component insertion holes) has become smaller, and in solder resist printing, all copper foil lands 3 It is difficult to print accurately without peeling completely or with the width of the remaining peeling not falling below the standard value, and even if the deviation width is small, the printing deviation and the punching deviation will deviate in opposite directions. Similarly, peeling 7 occurs.

Problems to be Solved by the Invention In such a conventional method, in order to remove the solder resist 2 at the peeled portion 7, a cutter knife is used.

Scraping was done with a handle, etc., but it took a huge amount of time, and due to forgetting to scrape or incomplete scraping, the solder did not completely reach the terminals of the components during the soldering process, resulting in many soldering defects. Ta.

The present invention is intended to solve these problems, and aims to form a uniform copper foil land without peeling and to completely eliminate soldering defects caused by solder resist.

Means for Solving the Problems In order to solve the above problems, the present invention includes a conductive pattern formed on at least one side of an insulating substrate, and a high density land such as an IC land having a pitch of at least 1.78 fi. A solder resist is formed on all or part of the conductive pattern, and a protrusion toward the insulating substrate is provided around the hole on the land forming side of the press punching die for forming the component insertion hole. By using a metal mold, the solder resist around the hole on the land can be easily and uniformly peeled off.

Therefore, according to the present invention, by providing a protrusion around the hole in the mold, in addition to the deflection and stress of the substrate during hole processing, pressure and impact are applied to the solder resist around the hole, thereby reducing the damage around the hole. Since the solder resist can be floated, the solder resist around the hole can be easily peeled off in a subsequent process.

Embodiment FIG. 2 is a cross-sectional view of a printed wiring board used in an embodiment of the present invention, in which a solder resist 2 is formed on all or part of the conductive pattern including the insulating substrate 1 and the copper foil land 3. This is what I did.

FIG. 1 shows a method according to an embodiment of the present invention,
The printed wiring board shown in FIG. When a component insertion hole is formed by shiveless punching using the lower die 41 and the die punch 6, the protrusion 6 applies an impact to the solder resist 2 around the hole and compresses it, causing structural destruction. .

Furthermore, at the moment of punching, the insulating substrate around the hole has 1° copper foil 3. The solder resist 2 is pulled downward by the mold punch 6, causing a deflection, and when the mold punch 6 comes out, it is pulled upward, causing the opposite deflection, so that stress also causes the copper around the hole to The adhesion between the solder resist 2 and the solder resist 2 on it deteriorates, and the solder resist 2 peels off and floats.

The protrusion 6 provided on the upper mold 4 had a height of about 10 μm and a width of 0.26 mm around the hole.

FIG. 3 is a cross-sectional view of the printed wiring board shown in FIG. 2 after being punched out using the upper die 4 provided with the protrusion 6 shown in FIG. solder resist 2
4 shows a peeled and floating state of the printed wiring board shown in FIG. 3 after removing the peeled and floating solder resist 2. The solder resist 2 could be easily and completely removed by adhering the adhesive tape and peeling off the adhesive tape. Insulating substrate 1 used in the example
is a paper phenol-based V-O board (board thickness 1.8ffi11
A copper foil (thickness: 35 μm) was used, and the ink for solder resist 2 was an ultraviolet curable ink. Moreover, commercially available cellophane tape was used as the adhesive tape.

In the above example, adhesive tape was used to remove the solder resist 2 around the holes, but it was confirmed that the same effect could be obtained by spraying high pressure water of 70 kg/ad or more. Further, a more stable effect can be obtained by combining blowing of compressed air, brush polishing, etc.

The above embodiment deals with the case where the solder resist 2 is formed all over the copper foil land 3, but for large lands etc. where the soldering area of the land portion is required, the land is formed using the conventional method. It is preferable to do so.

Effects of the Invention As is clear from the above examples, the present invention has the following effects.

(1) Since the solder resist is formed on the entire surface and the copper foil land for soldering is formed around the hole by press punching, it is possible to completely eliminate printing misalignment of the solder resist and peeling due to printing bleeding.

(2) A small and uniform copper foil land can be formed, and since the solder resist is peeled off after printing, the edges of that part are raised, completely eliminating syllate defects caused by solder bridges during soldering. .

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the printed wiring board at the moment it is punched out using a mold with protrusions in an embodiment of the printed wiring board manufacturing method of the present invention, and Figure 2 is a printed wiring board used in the embodiment of the present invention. Figure 3 is a cross-sectional view of the printed wiring board after it has been punched out using the protruding mold of the present invention after the solder resist has been formed on the board, Figure 4 is the solder resist around the land hole removed using adhesive tape. FIG. 5 is a cross-sectional view of the printed wiring board after forming the solder resist by the conventional method, and FIG. 6 is a cross-sectional view of the printed wiring board and the mold immediately after punching by the conventional method. 1... Insulating substrate, 2... Solder resist, 3... Copper foil land, 4... Upper mold of mold, 41...・Bottom die of the mold, 6...
Mold punch, 6...Mold protrusion, 7...
...Peeling part. Name of agent: Patent attorney Shigetaka Awano and 1 other person

Claims (1)

[Claims] A press punching mold for forming a conductive pattern on at least one side of an insulating substrate, applying and curing solder resist ink to all or part of the insulating substrate and the conductive pattern, and forming an electronic component insertion hole. A printed wiring board characterized in that a component insertion hole is formed around the hole on the side where the land is to be formed using a mold having a protrusion toward the insulating substrate side, and then the solder resist on the land portion is removed. manufacturing method.