JPH02284426A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a solder bump which has stable quality by forming a coupling metal layer after making a conductive paste perform thermosetting. CONSTITUTION:An aluminum wiring layer and an aluminum electrode 3 are provided on an oxide film 2 located on a silicon substrate 1 having an element region and an oxide silicon or a PSG insulating film 4 are deposited on the surface of the substrate and then, an opening 5 is provided by etching selectively. Subsequently, a printing mask 6 on which patterning is performed is mounted on the opening 5 and a conductive paste 7 is supplied onto the mask 6 and then, the paste 7 is poured onto the electrode 3 after squeezing it. Then the mask 6 is detached and, after making the paste set by heat treatment, a conductive resin layer 7a is formed. After that, the substrate 1 is immersed in a solder vessel and solder is allowed to deposit to the layer 7a and then, a solder bump 8 is obtd. The formation of the solder bump prevents the lowering of quality due to the dispersion of aluminum electrode treatment and the solder bump which has a stable quality is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a semiconductor device having bump electrodes.

[Conventional technology]

Conventionally, gold or copper has been used for bump portions of semiconductor devices having hump electrodes. Recently, there has been a demand for lower temperatures and lower costs, and solder (tin/lead based) has begun to be used as the metal for the bumps.

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

As shown in FIG. 2, an oxide film 2 is formed on the surface of a silicon substrate 1 having an element region (not shown), and aluminum wiring (not shown) connected to the element region is formed on the oxide film 2. An aluminum electrode 3 for external circuit connection 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 provide an opening. Next, a coupling metal film 10 made of titanium, nickel, copper, or the like is formed on the aluminum electrode 3 in the opening, and solder is further applied thereon to form a solder bump 8. There are vacuum evaporation methods and wet plating methods for forming the metal film for cup link on the aluminum electrode portion 3, and methods for attaching solder include direct immersion in a molten solder bath and wet plating methods. It is.

[Problem to be solved by the invention]

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

For example, in wet plating, the oxide film on the surface of the aluminum thin film must be removed 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, if the oxide film is insufficiently etched, it will lead to poor adhesion of the coupling metal. In either case, the strength of the solder bump provided on the cup link metal is poor, and the quality is extremely unstable.

Further, in order to provide a coupling metal film by vacuum evaporation, several lamination steps and vacuum treatment are required, resulting in a very expensive solder hump element.

[Means for Solving the Problems] A method for manufacturing a semiconductor device of the present invention provides a first insulating film on a semiconductor substrate having an element region, and a wiring connected to the element region on the first insulating film. a step of providing a second insulating film on the surface including the wiring and selectively etching it to form an opening above the wiring; and a step of forming a conductive resin on the wiring in the opening by a printing method. The method includes a step of forming a film, and a step of welding solder onto the conductive resin film to form solder bumps.

〔Example〕

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

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

First, as shown in FIG. 1 (a), an aluminum wiring (not shown) connected to the device region is formed on an oxide film 2 provided on a silicon substrate 1 having a device region (not shown).
Then, an aluminum electrode 3 for external circuit connection 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 insulating HtA 4 on the aluminum electrode 3 is selectively etched to form an opening 5.

Next, as shown in FIG. 1(b), the patterned printing mask 6 is aligned and placed on the opening 5, and the conductive paste 7 is supplied onto the printing mask 6 to remove the odor of roller oil. The conductive paste 7 is poured onto the aluminum electrode 3 in the opening 5 using a squeegee.

Next, as shown in FIG. 1(c), the printing mask 6 is removed and the conductive base I.7 is cured by 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 applied to the conductive resin layer 7a to form solder bumps 8. The conductive paste 7 is made of epoxy resin, polyimide resin, or the like in which noble metal powder such as gold or silver is dispersed.

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

〔Effect of the invention〕

As explained above, in the present invention, the metal layer for the cup link can be formed by thermally curing the conductive paste, so there is no quality deterioration due to variations in aluminum electrode processing in wet processing, and it does not require complicated vacuum deposition methods. Moreover, multi-step processing is unnecessary. Therefore, the present invention has the effect of realizing a method of manufacturing a semiconductor device having solder bumps with stable quality.

[Brief explanation of drawings]

FIGS. 1(a) to (d) are cross-sectional views of a semiconductor chip shown in order of steps to explain an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a semiconductor chip to explain a conventional method of manufacturing a semiconductor device. FIG. 1... Silicon substrate, 2... Oxide film, 3... Aluminum electrode, 4... Insulating film, 5... Opening, 6... Printing mask, 7... To conductive paste 1, 7a . . . Conductive resin layer, 8. Solder bump, 10. Metal film for cup link.

Claims (1)

[Claims] a step of providing a first insulating film on a semiconductor substrate having an element region, providing a wiring connected to the element region on the first insulating film, and providing a second insulating film on a surface including the wiring. A step of forming an opening on the wiring by selectively etching, a step of forming a conductive resin film on the wiring in the opening by a printing method, and a step of welding solder on the conductive resin film. A method of manufacturing a semiconductor device, the method comprising: forming solder bumps using a method of manufacturing a semiconductor device.