JP2811741B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device having a bump electrode.

[Conventional technology]

Conventionally, gold or copper has been used for a bump portion of a semiconductor device having a bump electrode. Recently, lower temperatures and lower costs have been required, and solder (tin / lead-based) has begun to be used as a metal for the bump portion.

FIG. 2 is a sectional view of a semiconductor chip for explaining a conventional semiconductor device.

As shown in FIG. 2, an oxide film 2 is formed on a surface of a silicon substrate 1 having an element region (not shown), and an aluminum wiring (not shown) connected to the element region is formed on the oxide film 2. An aluminum electrode 3 for connection to an external circuit is formed, an insulating film 4 is deposited on the surface including the aluminum electrode 3, and the insulating film 4 on the aluminum electrode 3 is selectively etched to form a hole. Next, a coupling metal film 10 of titanium, nickel, copper or the like is formed on the aluminum electrode 3 in the opening, and a solder is adhered thereon to form a solder bump 8. There are a vacuum deposition method and a wet plating method as a method of forming the coupling metal film 10 on the aluminum electrode portion 3, and a method of directly immersing in a molten solder bath and a wet plating method are used as a method of attaching solder. I have.

[Problems to be solved by the invention]

In the conventional semiconductor device described above, a method of providing a coupling metal film is a bottleneck in terms of quality and price.

For example, in wet plating, it is necessary to remove an oxide film from the surface of the aluminum thin film as a pretreatment, and it is difficult to control the processing conditions. This causes incomplete plating of the coupling metal due to excessive etching of the oxide film. On the other hand, insufficient etching of the oxide film leads to poor adhesion of the coupling metal. In either case, the strength of the solder bumps provided on the coupling metal becomes poor,
Quality is very unstable.

Further, in order to provide a coupling metal film by a vacuum deposition method, several lithography steps and a vacuum treatment are required, which results in a very effective solder bump element.

[Means for solving the problem]

The method of manufacturing a semiconductor device according to the present invention includes the steps of: providing a first insulating film on a semiconductor substrate having an element region, and providing a wiring connected to the element region on the first insulating film; Providing a second insulating film over the entire surface of the semiconductor substrate and then selectively etching the second insulating film to provide an opening in the second insulating film on the wiring; A step of directly forming a conductive resin film containing a noble metal such as gold or silver on the wiring by a printing method; and a step of forming a solder bump by welding solder on the conductive resin film. It is comprised including.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

1 (a) to 1 (d) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention.

First, as shown in FIG. 1 (a), on an oxide film 2 provided on a silicon substrate 1 having an element region (not shown), an aluminum wiring (not shown) connected to the element region and An aluminum electrode 3 for connecting an external circuit connected to the aluminum wiring is provided, and an insulating film 4 such as a silicon oxide film or a PSG film is deposited on the surface including the aluminum electrode 3. Next, the opening 5 is provided by selectively etching the insulating film 4 on the aluminum electrode 3.

Next, as shown in FIG. 1 (b), a patterned printing mask 6 is placed in alignment with the opening 5, and a conductive paste 7 is supplied on the printing mask 6, and a roller jig or the like is provided. And the conductive paste 7 is poured onto the aluminum electrode 3 in the opening 5.

Next, as shown in FIG. 1 (c), the printing mask 6 is removed, and the conductive paste 7 is cured by a heat treatment to form a conductive resin layer 7a.

Next, as shown in FIG. 1 (d), the semiconductor substrate 1 is immersed in a molten solder bath, and solder is adhered to the conductive resin layer 7a to form a solder bump 8. The conductive paste 7 is obtained by dispersing a noble metal powder such as gold and silver in an epoxy resin or a polyimide resin.

Here, after selectively printing the solder paste on the conductive resin layer 7a of FIG. 1 (c), the solder paste is heated and melted to form a solder layer on the conductive resin layer 7a. Alternatively, the solder bumps 8 may be formed, and the height of the solder bumps 8 can be controlled by adjusting the thickness of the printed solder paste.

〔The invention's effect〕

As described above, the present invention can form a coupling metal layer by heat-curing a conductive paste, so that there is no quality deterioration due to variation in aluminum electrode processing in wet processing, and it is complicated like a vacuum evaporation method. In addition, processing over multiple steps is unnecessary. Therefore, the present invention has an effect that a method of manufacturing a semiconductor device having solder bumps of stable quality can be realized.

[Brief description of the drawings]

1A to 1D are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention, and FIG. 2 is a semiconductor chip for explaining a conventional method of manufacturing a semiconductor device. FIG. DESCRIPTION OF SYMBOLS 1 ... Silicon substrate, 2 ... Oxide film, 3 ... Aluminum electrode, 4 ... Insulating film, 5 ... Opening, 6 ... Printing mask, 7 ... Conductive paste, 7a ... Conductive resin Layer, 8
…… Solder bump, 10 …… Coupling metal film.

Claims (1)

(57) [Claims] A step of providing a first insulating film on a semiconductor substrate having an element region and providing a wiring connected to the element region on the first insulating film; and forming a wiring on the entire surface of the semiconductor substrate including the wiring. A step of selectively etching the second insulating film after providing the second insulating film to form an opening in the second insulating film on the wiring, and a method of printing on the wiring in the opening. Forming a conductive resin film directly containing a noble metal such as gold, silver, and the like, and forming a solder bump by welding solder on the conductive resin film. Semiconductor device manufacturing method.