JPH0260137A - Board for semiconductor element mounting use - Google Patents

Abstract

PURPOSE:To obtain a copper foil suitable for a board for semiconductor element mounting use by a method wherein an insulating layer consisting of an inorganic substance is formed on the copper foil. CONSTITUTION:An insulating layer 2 consisting of an inorganic substance is formed on a copper foil 1. Materials usable for the formation of the insulating layer consisting of this inorganic substance are an oxide, a nitride, a carbide and the like. Concretely, such materials having electrical insulation properties as an Si oxide, an Al oxide, a titanium oxide, a tantalum oxide, an Si nitride, an Al nitride and an Si carbide can be effectively used. In such a way, as the insulating layer consisting of the inorganic substance is formed on the copper foil, a copper foil suitable for a board for semiconductor element mounting use can be obtained.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a substrate for mounting semiconductor elements, and more particularly, a copper foil suitable for a substrate for mounting semiconductor elements having a structure that does not require an adhesive, and its use. The present invention relates to a substrate for mounting semiconductor devices.

[Conventional technology and its issues]

In recent years, there has been rapid progress in technology for mounting semiconductor elements on substrates. Especially tape automatic wiring connection (TapeAutoma)
ted Bonding (hereinafter abbreviated as TAB) is a technology that connects semiconductor elements formed with integrated circuits (hereinafter abbreviated as IC chips) to a circuit board for mounting semiconductor elements without wire bonding. Currently, research and development are actively progressing as high-density packaging technology is required to enable wiring connections for IC chips having such a large number of external connection wirings at once.

There are two types of substrates used for TAB: two-layer structure and two-layer structure. In both structures, as shown in Figure 4a (two-layer structure) and Figure 4b (two-layer structure), IC The resin film 3 must be perforated at the location where the chip is to be mounted. This is because even a heat-resistant resin film has difficulty withstanding the temperature at which the IC chip is mounted.

Therefore, drilling is performed using different methods for the two-layer structure and the three-layer structure.

In a TAB with a two-layer structure, holes are formed in the resin film by etching.

However, in the case of heat-resistant resin films, this etching is difficult. - This is because the heat-resistant resin film used for TAB for boat fishing also has excellent chemical resistance. On the other hand, in the case of a TAB with a three-layer structure, holes can be formed in advance by die-cutting, punching, etc., so in the conventional technology, this TAB with a three-layer structure is mainly used for mounting semiconductors. I've been exposed to it.

However, this three-layer structure TAB is made by bonding copper foil and heat-resistant resin film with adhesive, and because it uses an adhesive with low heat resistance, TAB
A major problem is that the heat resistance of the resin film is lower than that of the resin film. For this reason, it is desired to develop mounting technology using TAB with a structure that eliminates the need for adhesives, and conventionally, in the case of two-layer structures that do not require adhesives, technology for etching heat-resistant resin films has been actively studied. It has been.

In order to develop a technology that eliminates the need for etching technology itself, the inventors of the present invention have carefully studied the TAB mounting process. It has been found that a heat resistance of about 1 second is substantially sufficient, and that this heat resistance can be provided by forming a specific insulating layer.The present invention was made based on this knowledge. This is what happened.

[Means to solve the problem]

That is, the present invention provides a copper foil suitable for a substrate for mounting a semiconductor element, characterized in that an insulating layer made of an inorganic substance is formed on the copper foil, and a copper foil made of an inorganic substance is formed on the copper foil. This is a substrate for mounting a semiconductor element, characterized in that an insulating layer is formed thereon, and a resin film layer is further formed on the edge layer.

[Disclosure of the invention]

As illustrated in FIG. 1, the present invention is a copper foil suitable for a substrate for mounting semiconductor elements, characterized in that an insulating layer 2 made of an inorganic substance is formed on a copper foil 1, and , second
As shown in FIG. C, this is a substrate for mounting a semiconductor element, in which an insulating layer N2 made of an inorganic material is formed on a copper foil 1, and a resin film layer 3 is further formed on the insulating layer.

Materials that can be used to form the insulating layer made of an inorganic substance of the present invention include oxides, nitrides, carbides, etc., and specifically, silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, silicon nitride, and nitride. Electrically insulating materials such as aluminum and silicon carbide can be effectively used. In order to form the insulating layer on the copper foil, either a physical method or a chemical method may be used.

However, physical methods include sputtering and thin deposition, and chemical methods include chemical vapor deposition (Chemical vapor deposition).
Methods such as vapor phase growth such as VD method), plasma chemical vapor deposition method (PCVD method), sol-gel method, and thin film formation from a liquid material such as immersion method can be effectively used.

The insulating layer has the property of being able to withstand the heat load in the TAB process, preferably providing heat resistance for 1 second at 500°C as described above, and for this reason, the thickness of the insulating layer is 0.01 to 20 us. , preferably 0.1
As explained above, the present invention has an insulating layer 2 made of an inorganic material on a copper foil 1.
This copper foil is suitable for mounting substrates for semiconductor devices formed with .

Hereinafter, a preferred embodiment of the present invention will be explained with reference to FIG. In Figure 2 a, 0.1 to 15 μm is applied on copper foil 1.
An insulating layer 2 made of an inorganic material is formed to a thickness of approximately -. This is a copper foil suitable for a substrate for mounting a semiconductor element, which is one of the aspects of the present invention. Furthermore, as shown in FIG. 2, a resin film varnish, a resin film precursor, etc. 3° is the coating thickness, 10 to 200 μm, preferably 15 to 150 μm, particularly preferably 20 to 100 μm.
Coat and form to a certain thickness. The varnish of the resin film, the precursor of the resin film, etc. are cured according to a conventional method, and the second
A resin film 3 as shown in Figure C is formed on the insulating layer. This is a substrate for mounting a semiconductor element, which is another aspect of the present invention. Note that the insulating layer does not necessarily need to be provided all over the copper foil, and may be provided only on the portion corresponding to the position where the IC chip is mounted, as shown in FIG. 3, depending on the case.

FIG. 2d shows an IC
This is a cross-sectional view of the copper foil 1 in which an unnecessary portion has been removed by a conventional method so that a chip can be mounted, and represents the cross-sectional structure of the TAB of the present invention, which has a structure that eliminates the need for an adhesive. FIG. 2e is a cross-sectional view when the IC chip 4 is finally mounted, and shows an example of application of the present invention. In addition,
Please note that the vertical and horizontal sizes in Figures 1 and 2 have been arbitrarily selected, and the thickness of the material has been enlarged and emphasized for ease of explanation, especially in cross-sectional views. .

In its spirit, the present invention is not particularly limited to the copper foil and preferably the heat-resistant resin film; any materials that have been used in the prior art may be effectively used. Can be done. For example, as for copper foil, rolled W4 foil, electrolytic IV3 foil, etc. can be effectively used. Preferably, the heat-resistant resin film is made of polyimide, polyamideimide,
Resin film varnishes, resin film precursors, etc. such as polyparabanic acid, polyhydantoin, and polybenzimidazole can be effectively used.

〔Example〕

Hereinafter, embodiments of the present invention will be explained in more detail with reference to Examples.

(Example 1) Silicon oxide was formed as an insulating layer on a 35 μm rolled copper foil to a thickness of 0.2 μm by sputtering to form a copper foil suitable for mounting a semiconductor element as shown in FIG. A polyamic acid varnish, which is a precursor of polyimide, was applied onto the silicon carbide layer to a thickness of 100 μm, and then cured by imidization to form a heat-resistant polyimide film, as shown in Figure 2C. A substrate for mounting a semiconductor element was obtained.FIN was then etched away using a ferric chloride solution to form a circuit.

Instead of mounting an IC chip on the circuit, heat resistance was tested by contacting it with a copper rod heated to 500° C. for 1 second. After the test, no deterioration in the appearance or electrical properties of the heat-resistant film was observed. That is, it was confirmed that the substrate for mounting a semiconductor element of the present invention has sufficient heat resistance to withstand mounting of an IC chip.

[Example 2] A silicon oxide thin film with a thickness of 10 pm was formed as an insulating layer by a sol-gel method in which a tetraethoxysilane solution was applied on a 35 μm electrolytic copper foil, the solvent was removed, and the silicon oxide was formed by heating and baking to form a semiconductor device. We obtained a copper foil suitable for the mounting board. A 75 μm thick polyimide chlorophenol solution was applied onto the thin film.
The solvent was removed by heating to form a heat-resistant polyimide film to obtain a substrate for mounting a semiconductor element. The copper foil was then etched away to form a circuit. Example! The same heat resistance test was conducted and similar results were obtained, indicating that silicon oxide formed by the sol-gel method was also effective in the present invention.

〔Effect of the invention〕

As is clear from the above examples, the present invention provides a substrate with a structure that eliminates the need for adhesives, and eliminates the need for etching a heat-resistant resin film, which was difficult in conventional TAB technology. Therefore, it must be said that this technology will significantly advance TAB technology in the future and contribute significantly to high-density packaging technology, and its industrial applicability is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of an embodiment of the present invention. FIGS. 2a to 2e are cross-sectional views showing an example of an embodiment when the present invention is used in a TAB. FIG. 3 shows another embodiment of the present invention, and is a sectional view schematically showing the cross-sectional structure, and FIG. 4a and FIG. In a certain 0 diagram, 1-・-・
−・−・−Body foil, 2・−・・−・・−・・Insulating layer of inorganic material, 3−−−−−−−−・−Heat resistant resin film, 3゛ Resin film Precursors for varnish and resin films, etc., 4-・--・--IC chips, 5--
・－・－・・・－Indicates adhesive. Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A copper foil suitable for a substrate for mounting semiconductor devices, characterized in that an insulating layer made of an inorganic substance is formed on the copper foil. (2) A substrate for mounting a semiconductor element, characterized in that an insulating layer made of an inorganic substance is formed on a copper foil, and a resin film layer is further formed on the insulating layer.