JPH0531828B2 - - Google Patents

Abstract

PURPOSE:To obtain a new hybrid type three-dimensional IC which realizes high density electrical connection by a method wherein semiconductor chips are provide on both surfaces of an anisotropic conductive film and the semiconductor chips are connected to each other through stripe wirings in the anisotropic conductive film. CONSTITUTION:In an anisotropic conductive film 2, stripe wirings 3 are formed vertically to the surface of the film 2 and independently from each other. Semiconductor chips 4a and 4b have required number of connection electrodes 5a and 5b at the respective corresponding positions. The semiconductor chips 4a and 4b are aligned while the connection electrodes 5a and 5b are facing the anisotropic conductive film 2 and are laminated on both the surfaces of the anisotropic conductive film 2 by thermocompression bonding or mechanical pressure. With this constitution, the respective corresponding connection electrodes 5a and 5b are connected to each other through the stripe wirings 3. Therefore, significant improvement of mounting density, improvement of operation speed owing to the reduction of wiring lengths and improvement of functional performance owing to combination of the chips whose functions, materials, manufacturing processes and so forth are different can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a semiconductor device having a structure in which semiconductor chips are stacked.

<Conventional Technology> The degree of integration of integrated circuits (hereinafter referred to as ICs) is increasing rapidly, and it is inevitable that even higher levels of integration will continue to be required. However, because microfabrication technology has its limits, three-dimensional ICs have emerged as a means of achieving higher integration and performance without changing the standard dimensions of IC design. These three-dimensional ICs are generally divided into monolithic types and hybrid types. The former is on the same board
Although SOI technology is used to repeatedly form semiconductor layers, there are still many issues that need to be resolved.

On the other hand, the latter stacks two-dimensional ICs,
Since there are few technical problems, it is relatively easy to put it into practical use, and a device in which two devices are bonded together using a flip-chip method has been put into practical use. However, in the general flip-chip method, the electrode connection pitch is limited to a minimum of about 200 μm, making it difficult to connect electrodes at a high density at the element level.

<Problems to be Solved by the Invention> This invention has been made with attention to these problems and the purpose of providing a new hybrid type three-dimensional IC capable of high-density electrical connection. .

<Means for solving the problems> In order to achieve the above-mentioned object, the present invention has the following steps:
Anisotropic film produced by forming striped wiring with fine pitch on an insulating film, stacking multiple layers of this film and adhering them to each other, and then cutting into films at right angles to the direction of the striped wiring. Semiconductor chips are stacked on both sides of the conductive film with their connection electrodes facing the surface of the anisotropic conductive film, and the semiconductor chips on both sides are connected via striped wiring of the anisotropic conductive film. I am trying to connect electrically.

<Function> Semiconductor chips stacked on both sides of the anisotropic conductive film are connected between connecting electrodes via striped wiring of the anisotropic conductive film. Since it is relatively easy to form striped interconnections with fine pitches, it is possible to reduce the pitch of connection electrodes, and higher density semiconductor devices can be realized.

<Example> Next, the illustrated embodiment will be described.

FIG. 1 shows a sectional view of an embodiment of a hybrid type three-dimensional IC 1 according to the present invention. 2 is an anisotropic conductive film; 3 is an innumerable number of striped wirings formed independently from each other in a direction perpendicular to the surface of the anisotropic conductive film 2; 4a, 4;
b is a semiconductor chip having a predetermined number of connection electrodes 5a, 5b at corresponding positions,
The semiconductor chips 4a, 4b have connection electrodes 5a,
5b are aligned toward the surface of the anisotropic conductive film 2, and are laminated on both sides of the anisotropic conductive film 2 by thermocompression bonding or applying mechanical pressure. As a result, the corresponding connection electrodes 5a and 5b are connected to each other via the stripe wiring 3. FIG. 2 shows a cross section of the anisotropic conductive film 2 before the semiconductor chips 4a, 4b are laminated thereon.

FIG. 3 shows a cross-sectional view of a three-dimensional IC 11 according to another embodiment. In this embodiment, a wiring 6 is formed at a predetermined location on the surface of an anisotropic conductive film 2, and this is used as an electrode for leading to the outside, and other parts are the same as those in FIG. . FIG. 4 shows a cross section of the anisotropic conductive film 2 before the semiconductor chips 4a, 4b are laminated thereon.

In the structure described above, when the material of the anisotropic conductive film 2 is a thermoplastic resin, both chips 4a and 4b are tightly attached to the surface of the anisotropic conductive film 2 by thermocompression bonding, and the anisotropic conductive film 2 is made of a thermoplastic resin. The directional conductive film 2 also functions as an environmental protection film for the chips 4a and 4b,
This greatly contributes to improving reliability. Even if the anisotropic conductive film 2 is not made of thermoplastic resin, the chips 4a, 4b and the anisotropic conductive film 2 can be completely separated by applying mechanical pressure or using an adhesive as necessary. Glued.

Next, the anisotropic conductive film 2 used for forming the three-dimensional IC 1 or 11 will be described.

As a conventional technique corresponding to this anisotropic conductive film 2, a silicone rubber 21 shown in FIG.
Elastic connectors have a structure in which thin metal wires 22 are embedded, or structures in which insulating rubber 23 and conductive rubber 24 are stacked in layers as shown in FIG. 7b, or as shown in FIG. 7c. A hot press type anisotropic conductive film, etc., in which metal particles 26 are dispersed in an insulating rubber 25 as shown, has been developed.

However, in the case of the former elastic connector, the connection pitch is limited to about 200 μm, and even in the case of the latter anisotropic conductive film, the limit is about 150 μm, making it difficult to connect with a finer pitch. It is. Also, regarding the connection resistance, the former largely depends on the contact pressure, and the latter also varies greatly depending on the contact state between the carbon fibers and is extremely unstable.

On the other hand, the anisotropic conductive film of the present invention is produced by forming striped wiring with a fine pitch of tens of micrometers to several tens of micrometers on a thermoplastic or thermosetting insulating film, and stacking multiple layers of this film. After bonding them together, they are cut into a film at right angles to the direction of the striped wiring, allowing for high-density and stable connections. When thermoplastic resin is used as the insulating film, the anisotropic conductive film formed becomes a hot press type connector. Furthermore, even when an insulating film made of thermoplastic resin is used, an anisotropic conductive film can be produced by thermocompression bonding via an adhesive layer when overlapping the films. Further, the wiring material to be used is not particularly limited as long as it has good adhesion to the film, such as Al, Au, Ti, Cu, etc.

An example of the manufacturing process of such an anisotropic conductive film is shown in FIG.

First, polyimide is coated on the glass plate 14 to bring it into a semi-cured state, or thermoplastic resin is coated on the glass plate 14 to form an insulating film 15 having a thickness of several μm to 20 μm [FIG. 5a]. Then,
An Al film with a thickness of about 2 μm is formed by vapor deposition, and stripe wiring 16 with a pitch of about 10 μm is formed using photolithography [FIG. 5b]. Next, the insulating film 15 is peeled off from the glass plate 14, and as shown in FIG. 5c, a plurality of layers are stacked and thermocompressed with the striped wiring 16 aligned in the same direction. Then, as shown in FIG. 5d, the thickness is
Cut into films of 10 μm to several tens of μm. In this way, an anisotropic conductive film 2 in which countless striped wirings 16 are regularly arranged in a direction perpendicular to the surface of the film is obtained. Note that the stripe wiring 16 in FIG. 5d corresponds to the stripe wiring 3 in FIGS. 1 to 4.

FIG. 6 shows an example in which the insulating film is thermosetting. In FIG. 5a, the polyimide coated on the glass plate 14 is cured to form the insulating film 15, and an Al film of about 2 μm is coated on this. Formed by vapor deposition and 10μm using photolithography technology
Stripe wiring 16 having a pitch of about 100 psi is formed [FIG. 5b]. Peel this off from the glass plate 14 and
Align the direction of the stripe wiring 16 as shown in figure a,
A plurality of layers are stacked alternately with adhesive layer 17 and bonded by thermocompression. Then, as shown in FIG. 6b, the stripe wiring 16
Cut the film into a film with a thickness of 10 μm to several tens of μm in a direction perpendicular to . As a result, an anisotropic conductive film 2 in which a countless number of striped wirings 16 (ie, 3) are regularly arranged in a direction perpendicular to the surface of the film is obtained.

Note that the glass plate 14 used in these Examples serves as a support during the production of the insulating film, and may not be used if unnecessary.

Furthermore, in the embodiments shown in FIGS. 1 and 3, the semiconductor chips 4a and 4b are described as having the same size, but according to the present invention, chips of different sizes are pasted together to form a hybrid type three-dimensional IC.
Of course, it is also possible to configure

<Effects of the Invention> As is clear from the above-described embodiments, the present invention involves forming striped wiring with fine pitches on an insulating film, stacking a plurality of layers of the film and adhering them to each other, and then changing the direction of the striped wiring. Using an anisotropic conductive film manufactured by cutting the anisotropic conductive film into a film shape at right angles to the It is designed to electrically connect semiconductor chips on both sides, and it is relatively easy to form striped wiring within the anisotropic conductive film at a fine pitch, so the pitch of the connecting electrodes can be made small. This makes it possible to achieve high density semiconductor devices.

Therefore, according to the present invention, many effects can be achieved, such as a dramatic improvement in packaging density, an improvement in operating speed by shortening the wiring length, and an improvement in functionality by combining chips with different functions, materials, manufacturing processes, etc. is expected.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG.
The figure is a sectional view of an anisotropic conductive film used in the same example, FIG. 3 is a sectional view of another example, and FIG. 4 is a sectional view of an anisotropic conductive film used in the same example. 5a to 5d each show an example of the manufacturing process of an anisotropic conductive film, and FIGS. 6a and 6b each show another example of the manufacturing process of an anisotropic conductive film. The figures shown in FIGS. 7a to 7c are sectional views of conventional examples corresponding to the anisotropic conductive film of the present invention, respectively. 1, 11... Three-dimensional IC (semiconductor device), 2...
Anisotropic conductive film, 3, 16...stripe wiring, 4a, 4b...semiconductor chip, 5a, 5b...
...Connection electrode, 6...Wiring (lead electrode), 15
...Insulating film, 17...Adhesive layer.

Claims (1)

[Claims] 1. Stripe wiring with fine pitches is formed on an insulating film, multiple layers of this film are stacked and bonded to each other, and then the film is cut at right angles to the direction of the stripe wiring. Semiconductor chips are laminated on both sides of the anisotropic conductive film produced in this way, with their connection electrodes facing the surface of the anisotropic conductive film, and then the semiconductor chips are laminated on both sides of the anisotropic conductive film, and the semiconductor chips are laminated on both sides of the anisotropic conductive film. A semiconductor device characterized in that semiconductor chips on both sides are electrically connected. 2 Form wiring on the surface of the anisotropic conductive film,
2. The semiconductor device according to claim 1, wherein the wiring is an electrode for leading to the outside. 3. The semiconductor according to claim 1 or 2, wherein the anisotropic conductive film is obtained by thermocompression-bonding the insulating film to each other using thermoplasticity and then cutting it into a film shape. Device. 4. The anisotropic conductive film according to claim 1 or 2, wherein the anisotropic conductive film is obtained by adhering non-thermoplastic insulating films to each other via an adhesive layer and then cutting them into film shapes. Semiconductor equipment.