JPH06139824A - Anisotropic conducting film - Google Patents

Abstract

PURPOSE:To satisfactorily arrange a conducting filler in an anisotropic conducting resin layer and improve the reliability of the connection between a substrate and an IC chip. CONSTITUTION:An anisotropic conducting film used for the mounting of elements is provided with an anisotropic conducting resin layer 13 made of a thermoplastic resin containing a conducting filler, thermosetting resin layers 14, 16 covering both faces of the anisotropic conducting resin layer 13, and cover films 15, 17 covering the surfaces of the thermosetting resin layers 14, 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive film for mounting an element on a substrate, and more particularly to a structure of an anisotropic conductive film for mounting an IC chip component.

[0002]

2. Description of the Related Art Conventionally, regarding the connection of elements using an anisotropic conductive resin, "Monthly Semiconductor W
Orld special edition, Surface Mount Technology Autumn 90 issue Press Journal, Inc., issued September 1, 1990 P. 259-262 "and the like.

FIG. 3 is a sectional view of a step of connecting a substrate and an IC chip using such a conventional anisotropic conductive adhesive. Hereinafter, a conventional method for connecting a substrate and an IC chip using an anisotropic conductive adhesive will be described. First, as shown in FIG.
An anisotropic conductive resin 3 is thinly and uniformly supplied to a predetermined position on the substrate 1 on which the substrate electrode 2 is formed.

Next, as shown in FIG. 3B, the electrodes 5 of the IC chip 4 and the substrate electrodes 2 are aligned. From this state, the IC chip 4 is pressed against the substrate 1, and the resin is cured by an appropriate method (thermosetting, thermoplastic or ultraviolet curing, etc.) while applying a load, and connection is performed.

[0005]

However, the above-described conventional method for connecting a substrate and an IC chip has the following problems. Generally, thermosetting or thermoplastic resin is often used as the resin in which the conductive filler is mixed.

When a thermosetting resin is used, the substrate-IC
Due to the heating at the time of chip connection, the viscosity of the resin decreases sharply, the conductive filler flows, and it flows out from the electrode,
This has been a cause of opening between the IC chips. On the other hand, when a thermoplastic resin is used, the hardness of the resin changes depending on the temperature. Therefore, after the IC chip is connected to the substrate, the thermoplastic resin softens at high temperature and the conductive filler flows to improve the reliability of the connection. There was a drawback that it lacked.

In order to eliminate the above problems, it is an object of the present invention to provide an anisotropic conductive film in which conductive fillers are well arranged to improve the reliability of the connection between the substrate and the IC chip. Is.

[0008]

In order to achieve the above-mentioned object, the present invention provides an anisotropic conductive film used for mounting an element in an anisotropic conductive resin layer comprising a thermoplastic resin containing a conductive filler, A thermosetting resin layer covering both surfaces of the anisotropic conductive resin layer is provided.

The surface of the thermosetting resin layer is covered with a cover film.

[0010]

According to the present invention, as shown in FIG. 1, in an anisotropic conductive film used for mounting an element, an anisotropic conductive resin layer 1 made of a thermoplastic resin in which a conductive filler is distributed.
Since both surfaces of 3 are structured to be covered with the thermosetting resin layers 14 and 16, the conductive filler is present in the thermoplastic resin, does not flow out even in a heated state, and is good even on a minute electrode. Can be placed in Further, the anisotropic conductive resin layer 1
Since both sides of 3 are covered with the thermosetting resins 14 and 16, they serve as a reinforcement for the element connecting portion, and a stable connection can always be obtained when connecting the element to the substrate.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an anisotropic conductive film manufacturing process showing an embodiment of the present invention. The method for producing the anisotropic conductive film according to the present invention will be described below. First, as shown in FIG. 1A, a cover film 12 having the same size as the area of this stage is placed on a flat stage 11 having a frame around it.

Next, as shown in FIG. 1B, an anisotropic conductive resin is supplied on the cover film 12 so as not to mix bubbles with the entire surface of the stage 11 to form an anisotropic conductive resin layer 13. . As this anisotropic conductive resin 13, a thermoplastic resin in which a conductive filler is uniformly mixed is used. Then, as shown in FIG. 1C, the anisotropic conductive resin layer 13 is formed.
Then, a thermosetting resin is supplied and the thermosetting resin is semi-cured by heat to form the thermosetting resin layer 14. Then, the cover film 15 is covered over this.

Next, as shown in FIG. 1 (d), the one formed up to this point is turned upside down, and then the cover film 12 attached first is removed. Subsequently, a thermosetting resin is further supplied from above, and the resin is similarly semi-cured by heat to form the thermosetting resin layer 16. Next, FIG.
As shown in (e), the thermosetting resin layer 16 is covered with the cover film 17.

Finally, as shown in FIG. 1F, the film is taken out of the stage 11 to complete the production of the anisotropic conductive film according to the present invention. The above-mentioned method for producing an anisotropic conductive film is one method for obtaining a film having the present structure, and is not limited to the above-mentioned production method. 2A to 2D are process sectional views showing an example in which the anisotropic conductive film according to the present invention is used for element connection.

An example of using the anisotropic conductive film according to the present invention for device connection will be described below with reference to FIG. First, as shown in FIG. 2A, the lower cover film 1
Peel off 5. Next, as shown in FIG. 2B, the anisotropic conductive film from which the lower cover film 15 has been peeled off is attached to the substrate having the electrodes 22 or the IC chip 21.

Next, as shown in FIG. 2C, the cover film 17 on the opposite side (upper side) is peeled off. Next, FIG.
As shown in (d), this anisotropic conductive film and the electrode 2
4 is connected to the substrate or the IC chip 23. Next, as shown in FIG. 2E, appropriate heat and load are applied from above to complete the connection of the elements. Here, 25 is a thermosetting resin layer, and 26 is a thermoplastic resin containing a conductive filler.

There is no outflow of conductive filler in this connection,
Good connection is possible even with temperature changes. Furthermore, at the end of the connection, resin or the like may be supplied from around the substrate or the IC chip to reinforce the connection. Since the elements are connected in this way, the heating at the time of connection prevents outflow of the conductive filler in the thermoplastic resin covered by the thermosetting resin layer, and prevents the temperature change after connection. Also, since the thermosetting resin layer functions as a protective layer, good connection can be maintained.

The present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these modifications are not excluded from the scope of the present invention.

[0019]

As described above in detail, according to the present invention, in an anisotropic conductive film used for mounting an element, an anisotropic conductive resin layer made of a thermoplastic resin containing a conductive filler, and an anisotropic conductive resin layer Since the thermosetting resin layer covering both sides of the one-side conductive resin layer is provided, the outflow of the conductive filler in the thermoplastic resin covered by the thermosetting resin layer is prevented.

Therefore, the conductive filler can be satisfactorily arranged even on the minute electrodes. Further, the thermosetting resin layer functions as a protective layer even when the temperature changes after the connection, so that a good connection can be maintained and the reliability of the connection can be improved. Further, since both sides of the anisotropic conductive resin are covered with the thermosetting resin, it serves as a reinforcement of the element connecting portion, and a stable connection can always be obtained when connecting the element to the substrate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a process of manufacturing an anisotropic conductive film showing an example of the present invention.

FIG. 2 is a process sectional view showing an example in which the anisotropic conductive film according to the present invention is used for element connection.

FIG. 3 is a sectional view of a step of connecting a substrate and an IC chip using a conventional anisotropic conductive adhesive.

[Explanation of symbols]

 11 stage 12, 15, 17 cover film 13 anisotropic conductive resin layer 14, 16, 25 thermosetting resin layer 21, 23 substrate or IC chip 22, 24 electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Ikebata 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (2)

[Claims] 1. An anisotropic conductive film used for mounting an element, comprising: (a) an anisotropic conductive resin layer made of a thermoplastic resin containing a conductive filler; and (b) heat covering both surfaces of the anisotropic conductive resin layer. An anisotropic conductive film having a curable resin layer. 2. The anisotropic conductive film according to claim 1, further comprising a cover film that covers the surface of the thermosetting resin layer.