JP3028413B1 - Electronic circuit device - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide an inexpensive electronic circuit device and a liquid crystal display device by improving the yield by preventing pattern peeling of a film substrate. SOLUTION: A pattern for connecting an IC is extended toward a center of the IC to form a peeling prevention pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable device or the like, a liquid crystal display device used for an electronic organizer, and an electronic circuit device on which an IC is mounted on a bare chip.

[0002]

2. Description of the Related Art A liquid crystal display device has a driver IC package and C,
COF (Chip On FP) in which chip parts such as R and electronic parts such as package ICs are mixedly mounted on a film substrate.
A product in which C) is mounted on a liquid crystal panel has begun to be mass-produced. Conventionally, a film substrate has been formed by applying a film-like adhesive to a polyimide film, pasting a Cu foil of a manufacturing method such as rolling or electric field and patterning it, and performing resist coating, electric field plating, or electroless plating.

[0003] The film substrate having the three-layer structure is not suitable for fine patterns of 100 microns or less in terms of dimensional stability because the adhesive is deformed by heat and humidity. Therefore, a film substrate from which the adhesive has been removed has been developed. There are two manufacturing methods for a two-layer film substrate without an adhesive layer. One is a casting method in which a polyamic acid varnish is applied to a Cu film and the solvent is removed and then cured, and a vapor deposition method in which a Cu thin film is formed on a polyimide film by sputtering or vapor deposition and then Cu is laminated by electrolytic plating.

[0004] The difference between the film substrates of the two manufacturing methods is that
This is the thickness of Cu. The thickness of Cu used in the casting method is typically 18 microns, and recently 12
Microns are being mass-produced. Also, 9 microns is under development. In the vapor deposition method, the thickness of Cu can be from 2 to 18 microns. To form a fine pattern,
The thinner the thickness of Cu, the easier the manufacturing method. For a pattern pitch of 100 microns or less, a film substrate formed by a vapor deposition method was suitable.

[0005] Further, in the case of bare chip mounting of an IC, when connection is performed by using an adhesive, a different bump is formed on the circuit board by using a plating bump formed by plating a bump made of Au on the IC pad or a stud bump applying wire bonding. It has been press-bonded with an isotropic conductive film or transferred to a substrate by transferring a silver paste to a bump, and an underfill has been filled and connected between them.

[0006] When a metal diffusion connection is used, an IC
Using solder for the bumps, soldering to the electrodes of the substrate and filling the underfill, and using Au for the bumps of the IC, performing Sn plating on the electrodes on the substrate side, and performing Au-Sn diffusion connection to fill the underfill. I was As for the bump pitch of the external connection electrode of the IC, for example, a liquid crystal drive IC is mass-produced with a pitch of 80 μm, but a pitch of 50 μm or 40 μm has begun to be developed.

A liquid crystal display device has been manufactured by connecting an IC to a film substrate and further connecting the film substrate to a liquid crystal panel.

[0008]

In order to form a pattern at a pitch of 40 microns, the width of the pattern is 10 to 15
Micron. For this reason, a film substrate formed by a vapor deposition method is used, but the vapor deposition method has poor adhesion between polyimide and Cu. In order to improve the adhesion, a thin film of, for example, chromium, chromium alloy, chromium-based ceramic, nickel, cobalt, palladium, titanium, zirconium, molybdenum, tungsten, nichrome alloy, or the like is deposited on the polyimide surface, Cu is deposited, and Cu plating is performed. Technology has been announced.

However, even when these techniques are used, in the patterning step and the surface treatment step, a defect that the pattern is peeled off from the polyimide occurs as the pattern width becomes smaller. Peeling is performed so as to curl from the tip of the pattern.
It is not easy to connect an IC to this stripped pattern. An object of the present invention is to obtain a pattern shape that prevents the pattern from peeling.

[0010]

In order to solve the above problems, an electronic circuit device in which an IC is connected face-down to a film substrate on which a metal pattern is formed on at least an insulating film, and the electronic circuit device is connected to a liquid crystal panel. In a liquid crystal display device, a plurality of patterns for connecting a plurality of bumps of an IC are formed on a film substrate, and the pattern is extended toward the center of the IC to form a large pattern for preventing peeling. , This defect was prevented.

Further, when the pattern pitch is particularly fine, it is not possible to form a pattern for preventing peeling on each pattern. Therefore, the yield was improved by forming the peeling prevention patterns every several patterns. The film substrate used for the electronic circuit device and the liquid crystal display device configured as described above can prevent peeling of the fine pattern or reduce the incidence.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram of a first embodiment of the present invention. C to connect bumps of IC to polyimide film 1
An 8 micron thick pattern 2 of u is formed. Pattern 2 is 30 microns wide. The bump of the IC is bonded to the connection position 4. The bump pitch is 1
00 micron pitch. The pattern 2 extends in the direction of the center of the IC, and has the peel prevention pattern 3 of the present invention formed thereon.

The anti-peeling pattern 3 is 70 microns wide and 100 microns long. Since the peel prevention pattern 3 thus formed has a large area in close contact with the polyimide, the peeling stress generated between the polyimide and Cu causes
Since the adhesive force is large, peeling of the pattern 2 can be prevented. Sn plating on the pattern of the film substrate,
The IC is connected by thermocompression bonding. Further, the liquid crystal display device is completed by connecting the film substrate to the terminals of the liquid crystal panel.

FIG. 2 is a diagram of a second embodiment of the present invention. A pattern 2 of 6 μm thick made of Cu for connecting bumps of an IC is formed on a polyimide film 1. Pattern 2 is 15 microns wide. The bump of the IC is bonded to the connection position 4. The bump pitch is a 40 micron pitch. Pattern 2 is an IC every other pattern
Extending in the center direction, the peeling prevention pattern 3 of the present invention is formed.

The peel prevention pattern 3 is 55 microns wide and 100 microns long. Since the peel prevention pattern 3 thus formed has a large area in close contact with the polyimide, the peeling stress generated between the polyimide and Cu causes
Since the adhesive force is large, peeling of the pattern 2 can be prevented. At a pitch of 40 microns, it is difficult to form the peeling prevention patterns 3 on all the patterns 2 in terms of layout, but the peeling occurrence rate can be suppressed.

In this embodiment, the separation preventing pattern 3 cannot be laid out near the corner of the IC. The peel prevention pattern 3 may be provided every two patterns. The pattern of the film substrate is plated with Sn, and the IC is connected by thermocompression bonding. Further, the liquid crystal display device is completed by connecting the film substrate to the terminals of the liquid crystal panel.

[0017]

As described above, according to the present invention, pattern peeling can be prevented by the pattern shape, and the yield is improved. Therefore, an electronic circuit device and a liquid crystal display device having an IC mounted on a film substrate can be provided at low cost.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a pattern according to the present invention.

FIG. 2 shows a second embodiment of the pattern of the present invention.

FIG. 3 shows a prior art embodiment;

FIG. 4 is a sectional view in which a film substrate, an IC, and a liquid crystal panel are connected.

FIG. 5 is a top view of the circuit surface of the IC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyimide film 2 Pattern 3 Exfoliation prevention pattern 4 IC bump connection position 5 IC 6 Underfill 7 Bump 8 Liquid crystal panel

(56) References JP-A-63-308398 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1345 H01L 23/12 H05K 1/18 H05K 3 / 34

Claims (2)

(57) [Claims] 1. A method of manufacturing a semiconductor device comprising the steps of:
Face IC on flexible substrate with pattern
In an electronic circuit device mounted down, it is connected to a bump of the IC provided in the pattern.
Peeling to prevent peeling from the connection position toward the center of the IC
The peel prevention pattern is provided by extending the prevention pattern.
The width of the pattern is wider than the pattern width at the connection position.
Electronic circuit device. 2. The method according to claim 1, wherein the separation preventing pattern includes a plurality of patterns.
2. The electronic device according to claim 1, wherein the electronic device is provided at every other turn.
Circuit device.