JPH05183009A - Ic module connection structure - Google Patents

Abstract

PURPOSE:To mount the IC module having connecting terminals of smaller pitches on a flexible circuit board without spoiling the advantages of the wiring pattern formation by a screen printing. CONSTITUTION:A wiring pattern of a metal foil is formed on the surface of a flexible circuit board 11. Inner side connecting terminals 13a having pitches of approximately 0.4mm each are provided. On its outer sides, the outer connecting terminals 13b having pitches of approximately 0.7 mm formed by a screen printing with a carbon-contained ink are provided and connected to the inner connecting terminals 13a. Then, the connecting terminals of an IC module are connected to the inner connecting terminals 13a. In this case, it is possible to make the pitches of the inner connecting terminals 13a smaller than the pitch limit, approximately 0.65mm, of the connecting terminals by the screen printing. Also, it is possible to form by the screen printing the wiring patterns other than the inner connecting terminals 13a on the flexible circuit board 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC module connection structure.

[0002]

2. Description of the Related Art In an IC chip mounting technique called a TAB (Tape Automated Bonding) method, as shown in FIG. 3, for example, an IC chip 3 is mounted on a square film substrate 2 made of a resin such as polyimide. IC module 1
Are mounted on the flexible circuit board 11. In this case, in the IC module 1, a wiring pattern made of a metal foil such as copper is formed on the lower surface of the film substrate 2, so that the finger leads 5 protrude into the opening 4 formed in the central portion of the film substrate 2. In addition to being provided, the connection terminals 6 are provided on the periphery of the lower surface of the film substrate 2, and bump electrodes (not shown) of the IC chip 3 arranged in the openings 4 are connected to the finger leads 5 by thermocompression bonding. It has a structured structure. As shown in FIG. 4, the flexible circuit board 11 is screen-printed with a carbon-containing ink at a predetermined position on the upper surface of the substrate body 12 made of a resin such as polyimide, corresponding to the connection terminals 6 of the IC module 1. Therefore, the connection terminal 13 is provided.

When the IC module 1 is mounted on the flexible circuit board 11, first, the anisotropic conductivity is provided on the upper surface of the flexible circuit board 11 in the region surrounded by the alternate long and short dash line in FIG. The adhesive 21 is screen-printed. Next, the IC module 1 is aligned and placed on the upper surface of the flexible circuit board 11. After this,
The peripheral portion of the lower surface of the film substrate 2 of the IC module 1 is attached to the flexible circuit board 11 using a heater chip (not shown).
When thermocompression bonded to the upper surface of the
Are connected to the connection terminals 13 of the flexible circuit board 11 via the anisotropic conductive adhesive 21. Thus, the IC module 1 is mounted on the flexible circuit board 11.

[0004]

By the way, in such a conventional IC module connection structure, the connection terminals 13 of the flexible circuit board 11 are formed by screen-printing a carbon-containing ink. Various patterns of wiring patterns can be formed relatively efficiently on the upper surface of the substrate body 12. However, the pitch of the connection terminals 13 formed by screen printing is about 0.65 mm at the minimum, and therefore the IC is limited.
Even if the module 1 has a connection terminal 6 having a pitch of, for example, about 0.4 mm, there is a problem that such an IC module 1 cannot be connected. An object of the present invention is to provide an IC module connection structure capable of mounting an IC module having a smaller pitch of connection terminals on a circuit board without damaging the advantages of wiring pattern formation by screen printing as much as possible. ..

[0005]

The present invention provides an IC module in which an IC chip is mounted on a rectangular film substrate having connection terminals with a pitch smaller than the limit of the pitch of the connection terminals by screen printing on the lower surface peripheral portion. An inner connection terminal is provided by forming a wiring pattern made of a metal foil on the upper surface of the substrate body so as to correspond to the connection terminal of the IC module, and the substrate on the outside of the inner connection terminal. A carbon-containing ink is screen-printed on the upper surface of the main body, so that a circuit board provided with an outer connection terminal having a pitch larger than the pitch of the inner connection terminal is connected to the inner connection terminal, The connection terminal of the IC module is connected to the inner connection terminal of the circuit board.

[0006]

According to the present invention, since the inner connecting terminals of the circuit board to which the connecting terminals of the IC module are connected are formed by the wiring pattern made of the metal foil, the pitch of the inner connecting terminals is determined by screen printing. Since the outer connecting terminals of the circuit board are formed by screen printing, the wiring pattern other than the inner connecting terminals connected to the connecting terminals of the IC module can be screen printed. Can be formed by, therefore, without impairing the advantages of the wiring pattern formation by screen printing as much as possible,
An IC module having a smaller pitch of connection terminals can be mounted on a circuit board.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a main part of a connection structure of an IC module in one embodiment of the present invention, and FIG. 2 shows a flexible circuit board of them. In these figures, parts having the same names as those in FIGS. 3 and 4 are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

The pitch of the connection terminals 6 provided on the periphery of the lower surface of the film substrate 2 of the IC module 1 is smaller than the pitch limit of the connection terminals of screen printing of about 0.65 mm, for example, about 0.4 mm. There is.
At a predetermined position on the upper surface of the substrate body 12 of the flexible circuit board 11, a wiring pattern made of a metal foil such as aluminum or copper is formed corresponding to the connection terminals 6 of the IC module 1, so that the inner connection is made. A terminal 13a is provided. In addition, since carbon-containing ink is screen-printed at a predetermined portion on the upper surface of the substrate body 12 of the flexible circuit board 11 outside the inner connecting terminals 13a, the pitch of the inner connecting terminals 13a is about 0.4 mm or more. The outer connection terminal 13b having a larger pitch, for example, about 0.7 mm, is connected to the inner connection terminal 13a.

When mounting the IC module 1 on the flexible circuit board 11, first, the anisotropic conductivity is provided on the upper surface of the flexible circuit board 11 in the area surrounded by the alternate long and short dash line in FIG. The adhesive 21 is screen-printed. Next, the IC module 1 is aligned and placed on the upper surface of the flexible circuit board 11. After that, the peripheral portion of the lower surface of the film substrate 2 of the IC module 1 is thermocompression-bonded to the upper surface of the flexible circuit board 11 by using a heater chip (not shown), and the connection terminals 6 of the IC module 1 interpose the anisotropic conductive adhesive 21. Flexible circuit board 1
1 is connected to the inner connection terminal 13a. Thus, IC
The module 1 is mounted on the flexible circuit board 11.

As described above, in this IC module connection structure, the inner connection terminals 13a of the flexible circuit board 11 to which the connection terminals 6 of the IC module 1 are connected are formed by a wiring pattern made of a metal foil such as aluminum or copper. Therefore, the pitch of the inner connecting terminals 13a is set to the limit of the pitch of the connecting terminals by screen printing of 0.65 m.
Since the pitch can be set to about 0.4 mm, which is smaller than about m, and the outer connection terminals 13b of the flexible circuit board 11 are formed by screen printing,
The wiring pattern other than the inner connection terminals 13a connected to the connection terminals 6 of the C module 1 can be formed by screen printing, and therefore the pitch of the connection terminals 6 can be reduced without impairing the advantage of forming the wiring pattern by screen printing as much as possible. The smaller IC module 1 can be mounted on the flexible circuit board 11. In addition,
By covering all the inner connecting terminals 13a with the anisotropic conductive adhesive 21, it is possible to prevent corrosion of the inner connecting terminals 13a made of metal such as aluminum or copper. Further, instead of the anisotropic conductive adhesive 21, the connection terminals 6 of the IC module 1 are previously plated with solder,
You may make it connect through this solder plating.

[0011]

As described above, according to the present invention, since the inner connection terminals of the circuit board to which the connection terminals of the IC module are connected are formed by the wiring pattern made of the metal foil, the inner connection terminals are formed. Can be made smaller than the limit of the pitch of the connection terminals by screen printing, and since the outer connection terminals of the circuit board are formed by screen printing, the inner connection connected to the connection terminals of the IC module Wiring patterns other than terminals can be formed by screen printing,
Therefore, it is possible to mount an IC module having a smaller pitch of connection terminals on the flexible circuit board 11 without impairing the advantage of forming a wiring pattern by screen printing as much as possible.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of an IC module connection structure according to an embodiment of the present invention.

FIG. 2 is a plan view of a part of the flexible circuit board according to the embodiment.

FIG. 3 is a cross-sectional view showing an example of a conventional IC module connection structure.

FIG. 4 is a plan view of a part of a flexible circuit board in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IC module 2 Film substrate 3 IC chip 6 Connection terminal 11 Flexible circuit board 12 Board body 13a Inner connection terminal 13b Outer connection terminal 21 Anisotropic conductive adhesive

Claims (1)

[Claims] 1. An IC chip mounted on a square film substrate having connection terminals at a peripheral portion of a lower surface, the connection terminals having a pitch smaller than a limit of pitch of connection terminals formed by screen printing.
An inner connection terminal is provided and an outer side of the inner connection terminal is formed by forming a wiring pattern made of a metal foil on the upper surface of the C module and the substrate body in correspondence with the connection terminal of the IC module. The carbon-containing ink is screen-printed on the upper surface of the substrate body in
A circuit board provided with outer connection terminals having a pitch larger than the pitch of the inner connection terminals connected to the inner connection terminals, and connecting the connection terminals of the IC module to the inner connection terminals of the circuit board. A connection structure for an IC module, characterized in that