JPS61207095A - Printed wiring board for thin type id card - 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 printed wiring board for thin IC cards, and more particularly, the present invention relates to a thin multilayer printed wiring board for IC cards on which electronic components such as semiconductors are mounted. .

Printed wiring boards for IC cards include cash withdrawal cards called CD cards, recognition cards called ID cards,
It is used for various purposes such as a medical chart called MC card and a telephone card called TC.

[Conventional technology]

Conventional printed wiring boards for IC cards mount electronic components such as semiconductors on a horizontal board on the same level as the conductive circuit formed on the smooth horizontal board, and electrically connect them by wire bonding. It's something that will be done.

Therefore, there is a protrusion corresponding to the thickness of the semiconductor product, and the IC
Contrary to the demand for thinner printed wiring boards for cards and for card surfaces to be smooth and horizontal, unevenness on the product surface cannot be avoided1.

In order to increase the density of printed circuit boards for IC cards by adding multiple functions, the thickness of the conductive plating for parts of the conductive circuits and conductive through-holes is usually copper plating, nickel plating, or gold plating. The formation of various plating layers results in a film thickness ranging from a maximum of 50 μm to a minimum of 16 μm, and the thickness of the conductive plating on this land also impedes smoothing of the IC card surface and makes it difficult to make the product thinner.

[Problem that the invention seeks to solve]

As mentioned above, in conventional printed wiring boards for IC cards, the plating thickness of the lands is increased by the number of boards when multi-layered, and in particular, the thickness of the land plating is increased by the number of boards, and in particular, the thickness of the land plating is increased by the number of boards. The lands provided at the ends protrude toward the back side of the IC card.

However, since the IC card must pass through a certain narrow gap, if the land portion provided at the end of the contact through hole protrudes, it will cause problems in terms of electrical contact.

Accordingly, the present invention provides a method for absorbing the protrusion of land portions such as contact through holes of the conventional printed wiring board for IC cards by some method to form the same horizontal plane as the other portions. In the surface layer,
A metal plating layer is formed, and at least six or
8 contact through holes, a plurality of through holes are formed in the intermediate layer, and the contact through hole is formed, and a plurality of through holes are formed in the intermediate layer, and A land is provided at the end of the contact through hole, a back layer in contact with the land has a shape that absorbs the protrusion of the land, a recess for mounting a semiconductor is formed in the intermediate layer, and By providing a thin printed wiring board for IC cards in which four parts for preventing the sealing resin from flowing out are integrally formed on the back layer, the drawbacks of conventional printed wiring boards for IC cards can be overcome. The purpose is to remove and improve.

Therefore, according to the present invention, at least the plating thickness of the land provided at the end of the contact through hole is absorbed so that it does not protrude, and only that thickness can be made thinner. It is possible to provide a printed wiring board for an IC card in which the sealing resin is housed in a recess (inside a cavity) in the board, and the sealing resin does not leak out to the outside of the recess.

[Means and effects for solving the problems] I of the present invention
In specifically explaining the printed wiring board for C card, it will be explained in detail based on the drawings.

FIG. 1 is a perspective view of a printed wiring board for a thin IC card according to the present invention, and FIG. 2 is a longitudinal sectional view substantially corresponding thereto.

1 is a printed wiring board, and the most typical one is:
Glass fiber reinforced epoxy resin substrate, paper phenolic resin substrate, paper epoxy resin substrate, glass polyimide resin substrate,
Glass triazine resin substrates, etc. A copper film such as a copper foil (10) must be formed on both sides of these substrates in advance.

IA is the surface layer of the first substrate, and mainly metal plating layers (two layers) are formed thereon.

1B is an intermediate layer of the substrate 1, which mainly includes a plurality of through holes (3A) and a semiconductor mounting recess (1D).
is formed.

The IC is the back layer of the first substrate, and mainly has recesses (IE) for preventing sealing resin outflow and recesses or holes for absorbing land thickness.

Further, a conductor circuit (2B) for bonding a semiconductor is formed in a part of the sealing resin outflow prevention recess (IE) provided in the intermediate layer (IB), and
) and the surface! A slot contact through hole (3B) is formed to conduct electricity to (LA), and a land (4) is formed at one end of the slot contact through hole (3B).

5 is an adhesive layer for bonding the substrates together.

The adhesive layer (the step is an uncured epoxy resin-impregnated glass cloth, a heat-resistant adhesive sheet, a liquid resin, etc.), and an adhesive layer with high properties such as adhesiveness, heat resistance, and durability is preferable.

The printed wiring board for thin IC cards of the present invention is basically composed of a surface layer, an intermediate layer, and a back layer as described above, but depending on the IC card fences and applications, it may be multi-functional or high-density. Because of this, it is necessary to increase the number of intermediate layers to two or more layers, or to increase the number of metal plating layers formed on the surface layer and the recesses or holes formed on the back layer to prevent sealing resin from flowing. The number and shape can be changed as appropriate.

Next, there are many ways to absorb the thickness of various metal platings (1), which is about 16 to 50 μm, which is the thickness of the land (4), which is the biggest feature of the substrate of the present invention. There are three different methods.

The first method is to form a recess (6) deeper than the land (thickness 1 from which the shank protrudes) and larger than the size of the land, as shown in the longitudinal cross-sectional view of FIG.

Part 2 is the land (4
) A method in which a recess or hole is provided in the substrate at the protruding part, deeper than the land thickness and larger than the land size, and the substrates are bonded to each other using only other parts so as not to form an adhesive layer (5) in this part. It is.

Part 3 is the land (5
) is fitted into the intermediate layer (IB) circle by flash processing using a high-temperature, high-pressure press.

The printed wiring board for an IC card of the present invention can be manufactured as described above, but it can also be manufactured by a method that can absorb the land protrusion, for example, a combination of the above three methods. I can do it. That is, (a) the back layer absorbs the protrusion of the land, and (b) the back layer has a recess or hole formed therein for absorbing the land thickness which is larger than the size of the land. (c) A form in which the adhesive layer with the intermediate layer is partially thinned or removed, and (c) a form in which the back layer absorbs the land protrusion. Alternatively, there is also a method in which the land portion is pressed into the intermediate layer and/or the back layer by flash processing in any combination.

Next, the most typical embodiment of the present invention will be described.

Example 1 For the intermediate layer, a printed wiring board with a thickness of 0.1fi or less (n thickness is denoted as t) was used, and in the same way as a double-sided printed wiring board, drilling, copper through-hole plating, patterning, etching, 8. After R printing, electrolytic nickel, and electrolytic gold plating, an adhesive layer is temporarily attached to the surface opposite to the bonding surface, and the semiconductor mounting part is punched out (the back side of the surface layer is a printed wiring board of 0.065 t). Similar to single-sided printed wiring boards, holes are punched, patterned, etched, and electrolytic nickel and electrolytically gold plated using a single-sided printed wiring board.This side becomes the semiconductor mounting side.Next, the intermediate layer and surface layer are heat-pressure coated. After bonding, holes for 6 or 8 contact through holes were drilled, copper through hole plating, patterning, etching, electrolytic nickel,
Apply electrolytic gold plating.

At this time, the land in the contact through hole portion of the bonding surface is plated with copper twice, electrolytically nickel plated, and electrolytically gold plated, and this land portion becomes approximately 40μ thicker than the thickness of the bonding terminal.

For the back layer, a 0.2t printed wiring board (printed wiring board from which all copper foil has been removed) is made with a reverse counterbore process larger than the land in the part that contacts the contact through hole part to form a recess. After forming a land thickness absorbing portion opposite to the above, an adhesive is temporarily attached to this portion, and a concave portion for preventing the sealing resin from flowing out is punched out.

Next, the intermediate layer, the front layer, and the back layer were bonded together using a hot pressure press, and then punched into a desired shape to obtain a printed wiring board for an IC card of the present invention as shown in Figure 3.

Example 2 Intermediate 1- was made using a 0.1 t printed wiring board, which was subjected to drilling, copper through-hole plating, pattern formation, etching, S, R printing, fR decomposition nickel, and electrolytic gold plating in the same way as a double-sided printed wiring board. After temporarily adhering an adhesive layer to the surface opposite to the bonding surface, the semiconductor mounting portion is punched out. For the back side of the surface layer, use a 0.065 t printed wiring board and drill holes in the same way as a single-sided printed wiring board.
Perform pattern formation, etching, electrolytic nickel, and electrolytic gold plating.

This surface becomes the semiconductor mounting surface. Next, the intermediate 11
After adhering the and surface layer by heat pressure coating, 6 or
Drill holes for 8 contact through holes, conduct copper through hole plating, pattern formation, etching, electrolytic nickel, and electrolytic gold plating. At this time, the land of the contact through hole portion of the bonding surface has two
The land portion is approximately 40μ thicker than the bonding terminal.

For the back layer, a 0°2t printed wiring board was used (a printed wiring board from which all copper foil had been removed), and a counterbore process and a hole larger than the land were made in the part that contacted the contact through hole part. After that, the adhesive removed from this part is temporarily bonded, and a concave part for preventing the sealing resin from flowing out is punched out.

Next, the intermediate layer, the front layer, and the back layer are bonded together using a heat-pressing press, and then punched into a desired shape to form a fourth layer.
A printed wiring board for an IC card of the present invention as shown in No. 13 was obtained.

Example 3 The intermediate layer was formed using a 0.1t printed wiring board, which was subjected to hole drilling, copper through-hole plating, pattern formation, etching, S, R printing, electrolytic nickel, electrolytic gold plating, and bonding in the same way as a double-sided printed wiring board. After temporarily adhering an adhesive layer to the opposite side, the semiconductor mounting portion is punched out. The surface layer is the back side.

Using a 0.065 t printed wiring board, drilling, patterning, etching, and electrolytic nickel and electrolytic gold plating are performed in the same way as for the single-sided printed wiring board.

This surface becomes the semiconductor mounting surface. Next, after adhering the intermediate layer and the surface layer by heat pressure coating, 6 or 8
Drill holes for two contact through holes, conduct copper through hole plating, pattern formation, etching, electrolytic nickel, and electrolytic gold plating. At this time, the lands of the free through holes on the bonding surface are plated twice with copper, electrolytic nickel plating, and electrolytic gold plating.

This land part is approximately 4mm thicker than the thickness of the bonding terminal.
It becomes thicker by about 0μ. In this state, the conductor and land portions on the surface of the board are heated to a temperature of 180"C and a pressure of 100K.
QM flash processing is performed for about 30 minutes to flatten the surface of the substrate by pushing it into the base material.

The back layer is temporarily bonded with an adhesive, and a concave portion for preventing the sealing resin from flowing out is punched out.

Next, the intermediate layer, the front layer and the back layer are bonded together using a thermopressure cutter, and then punched into a desired shape to form an IC card of the present invention having a thickness of 0.56a as shown in FIG. A printed wiring board was obtained.

〔Effect of the invention〕

As described above, in the IC card printed wiring board of the present invention, at least the thickness of the land portion is made thinner by various methods, and a recess is formed in the semiconductor mounting portion so that the semiconductor can be placed on the substrate surface. It has a structure that does not protrude, and furthermore, a stepped recess is formed in the resin-sealed part of the semiconductor to connect with the recess in the semiconductor mounting part, so that the shape can prevent the sealing resin from flowing out, and the thickness of the resin layer is also reduced. The structure is designed so that the printed circuit board does not protrude from the surface and become thick, and the land and circuit parts are not directly exposed on the back surface, making the overall thickness of the printed wiring board as thin as possible, making it the optimal structure for an IC card board. That is.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a printed wiring board for an IC card according to the present invention, FIG. 2 is a vertical sectional view of a part of the printed wiring board for a thin IC card according to the present invention, and FIGS. Thin I
It is a longitudinal cross-sectional view showing an embodiment of land thickness absorption of a printed wiring board for a C card. In the above drawing,

Claims (1)

[Claims] 1. A metal plating layer is formed on the surface layer, and has at least 6 or 8 contact through holes, and a plurality of through holes are formed in the intermediate layer. ,
and a land is provided at the end of the contact through hole, a back layer in contact with the land has a shape that absorbs the protrusion of the land, a recess for mounting a semiconductor is formed in the intermediate layer, and a semiconductor mounting recess is formed in the intermediate layer. The back layer is integrally formed with a recess for preventing the sealing resin from flowing out.
Printed wiring board for C card. 2. The form in which the back layer absorbs the protrusion of the land is such that the back layer is formed with a recess or a hole for absorbing the land thickness which is larger than the size of the land. A printed wiring board for a thin IC card as described in Scope 1. 3. The form in which the back layer absorbs the protrusion of the land is such that the thickness of the adhesive layer with the intermediate layer is partially thinned or removed. A printed wiring board for a thin IC card as described in Scope 1. 4. The thin type according to claim 1, wherein the back layer absorbs the protrusion of the land by pressing the land portion into the intermediate layer and/or the back layer by flash processing. Printed wiring board for IC cards.