JPH04184953A - Connection method of semiconductor device - Google Patents

Abstract

PURPOSE:To enable the high density mounting step to be performed easily by a method wherein, after the formation of a metallic film on an Al electrode on a semiconductor substrate, a resin film is formed on the whole surface and then a conductive paste is buried in an opening in the resin film so as to bond the conductive paste onto the electrode pattern of another substrate. CONSTITUTION:An Al electrode 2, a protective film 3 and a metallic film 4 are formed on a semiconductor substrate 1 and then a dry-film comprising sensitive resin in specific thickness is formed on the whole surface while the part on the electrode 2 is opened to form a resin film 12. Next, the paste 8 comprising resin with conductive filler scattered therein is buried in the opening part on the substrate 1. Next, after dividing the whole body into the chip units in specific size, the part filled up with the paste 8 and the electrode pattern 10 of a glass substrate 9 are aligned with each other and then the paste 8 is thermoset or photoset so as to connect the substrate 1 with the other substrate 9. Through these procedures, the resin sealing step of a mold resin can be eliminated simultaneously enabling the high density mounting step to be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for electrically and mechanically connecting a semiconductor device to a circuit board.

[Conventional technology]

Conventionally, methods for connecting a semiconductor device to a circuit board are as follows. The conventional method will be explained using FIG. All of FIG. 2 are cross-sectional views.

First, as shown in FIG. 2(a), an opening is formed in the protective film B so that the aluminum electrode 2 of the semiconductor substrate 1 on which a predetermined element is formed is exposed, and then the semiconductor substrate is opened as a plating common electrode film. 1. A metal film 4 is formed by laminating AJ, Cr, and Cu on the entire surface.

Next, as shown in FIG. 2(b), a photoresist is coated on the metal film 4 by a spin code method, exposed using a predetermined mask, and developed to form an opening on the aluminum electrode 2. A resist 5 is formed. Next, Figure 2 (
As shown in C), copper plating 6 and gold plating 7 are performed to form bumps 21.

Finally, unnecessary portions of the resist 5 and metal film 4 are removed to obtain the bump 21 structure shown in FIG. 2(d).

After the bump formation has been completed, the wafer is diced into single chips, and then a conductive paste 8 is transferred onto the surface of the bumps 21 and connected to the electrode pattern 10 on the glass substrate 9 as shown in FIG. , the conductive paste 8 is cured by heating.

Here, the electrode pattern 10 is indium tin oxide.

Furthermore, as shown in FIG. 2(f), the connection method involves injecting a molding resin 11 between the semiconductor substrate 1 and the glass substrate 9 and heating and hardening it.

[Problem to be solved by the invention]

However, in the conventional method described above, the bump forming process and the bonding process are long and complicated. In addition, when forming the resist 5 for plating by the spin code method,
This resist 5 can only be formed to a thickness of about several μm at a time. When the bumps 21 are formed by a wet plating method using the resist 5 as a mask, the plating grows isotropically, so that lateral spread □ becomes a problem. In other words, due to the unnecessary spread of the plating in the lateral direction, the distance between the bumps is restricted in order to obtain bumps of a desired size, making it unsuitable for forming high-density bumps.

Therefore, by forming the resist 5 for plating as thick as the height required for the bump, it is possible to suppress the spread of the plating in the lateral direction. However, when repeatedly applying the coating in layers using the spin code method, there are problems in quality stability and productivity.

In order to solve this problem, an object of the present invention is to provide a simple method for connecting electrode patterns on a semiconductor substrate and a circuit board, and which can increase the density.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a method for electrically and mechanically connecting a semiconductor device to a circuit board, in which a protective film is formed on the entire surface of the semiconductor substrate, and the protective film is further etched onto an aluminum electrode. A process of forming an opening on the surface and forming a metal film on the entire surface, a process of etching this metal film and forming a metal film on the aluminum electrode, and a process of forming a resin film on the entire surface and then forming a metal film on the resin film. It is characterized by comprising the steps of forming an opening on the resin film, embedding a conductive paste in the opening of the resin film, and bonding the electrode pattern of the substrate and the conductive paste.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained in order of steps using FIGS. 1(a) to ←). All of FIG. 1 are cross-sectional views.

- First, as shown in FIG. 1(a), a protective film 3 is formed so that the aluminum electrode 2 on the semiconductor substrate 1 on which predetermined elements are formed is exposed. The protective film 3 is a two-layer film formed by forming SiN to a thickness of 800 nm by CVD and further forming polyimide to a thickness of 2 μm.

In addition to the SiN film, SiO, PSG, etc. can also be used as the protective film 3.

Next, a metal film 4 is formed on the entire surface of the semiconductor substrate 1 by a vapor deposition method. The metal film 4 can also be formed by sputtering. The metal film 4 is made of Al1μm, Cr3nm, Cu800n
It has a laminated structure of m. It is desirable that the metal film 4 have good adhesion to the conductive materials formed above and below, and the above-mentioned combination is such that the metal film material and the conductive material do not interdiffuse with each other.

Next, a photoresist film (not shown) is formed on the entire surface of the semiconductor substrate 1, exposed and developed, and unnecessary portions of the metal film 4 are removed using an etching solution as shown in FIG. 1(b).
A metal film 4 is formed on the aluminum electrode 2. An ammonia-based solution is used as the etching solution for Cu, and a mixed aqueous solution of potassium ferricyanide and sodium hydroxide is used for Al. Cr is removed by lift-off when etching kl.

Next, as shown in FIG. 1(C), a dry film of photosensitive resin is formed with a thickness of 25 to 40 μm by a laminating method, and a resin film 12 having openings is formed on the aluminum electrode 2 by photolithography. Form. The opening diameter of the resin film 12 is desirably made to match that of the metal film 4 or to be slightly smaller than the metal film 4 from the viewpoint of stress relaxation. Furthermore, since the resin film 12 also serves to protect the IC chip after bonding, it needs to have good adhesion to the protective film 6 on the semiconductor substrate 1 and have heat resistance.

Next, as shown in FIG. 1(d), a conductive paste 8 in which a conductive filler is dispersed in a resin is embedded in the opening on the semiconductor substrate 1 by a squeegee method, dip method, or the like.

Next, a protective film (not shown) with a thickness of several μm is formed on the wafer surface, and the wafer-shaped semiconductor substrate 1 is divided into individual chips of a predetermined size by dicing.
This protective film is removed. Here, dicing is performed using resin film 1.
The conductive paste 8 may be buried in the opening of the resin film 12 after forming the chip 2 and forming a single chip.

Next, as shown in FIG. 1(e), the semiconductor substrate 1 and the glass substrate 9 are connected. The portion where the conductive paste 8 is embedded is aligned with the electrode pattern 10 of the glass substrate 9, and the conductive paste 8 is cured by heat or light. In the conventional method, in order to protect the IC chip, a molding resin 11 as shown in FIG. Since the film 12 plays a similar role, it becomes possible to eliminate the resin sealing process of the mold resin.

In addition, in the conventional method, since a metal such as copper was used as the core on the aluminum electrode 2, external stress directly affected the underlying layer, and the reliability of the deposited stress generated during plating was a problem. . However, in the connection method according to the present invention, by embedding the conductive paste 8 on the aluminum electrode 2, the stress can be relaxed by the resin, and no deposit stress is generated due to plating.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in the method of connecting a semiconductor device to a circuit board, by forming a resin film using a dry film on the semiconductor substrate, the resin film between the semiconductor substrate and the glass substrate is bonded. It becomes possible to omit the sealing process.

Furthermore, since the distance between the aluminum electrodes can be changed arbitrarily and the conductive paste can be embedded on the aluminum electrodes, high-density packaging is possible.

[Brief explanation of the drawing]

FIGS. 1(a) to (e) are cross-sectional views showing the method of connecting a semiconductor device to a substrate according to the present invention in order of steps, and FIGS. 2(a) to (f)
1A and 1B are cross-sectional views illustrating a method of connecting a semiconductor device to a substrate in the order of steps in a conventional example. 1... Semiconductor substrate, 2... Aluminum electrode, 3... Protective film, 4... Metal film, 8... Conductive paste, 10... Electrode pattern, 12... Resin film. Figure 1 (C) Figure 1 Figure 2 (b)

Claims (1)

[Claims] A process of forming a protective film on the entire surface of the semiconductor substrate, etching the protective film to form an opening on the aluminum electrode, and further forming a metal film on the entire surface, and etching the metal film and forming an opening on the aluminum electrode. forming the metal film on the substrate; forming a resin film on the entire surface and further forming an opening on the metal film of the resin film; embedding a conductive paste in the opening of the resin film; 1. A method for connecting a semiconductor device, comprising the step of bonding the electrode pattern and the conductive paste.