JPH0290618A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the adhesion between a wire and a metal pad and to reduce adhesion resistance and the like by a method wherein the upper layer passivation film is selectively etched using a resist pattern as a mask, then the lower layer passivation film is selectively etched using the upper passivation film as a mask. CONSTITUTION:After an electrode pad 2 has been formed on an insulating film 1, a silicon oxide film 3, which acts as the lower layer passivation film, is formed and then a polyimide film 4, which acts as the upper layer passivation film, is formed thereon. Subsequently, a resist pattern 5b is formed. After the polyimide film 4 has been selectively etched with an alkali solution using said resist pattern 5b as a mask, the resist pattern 5b is removed. Besides, a silicon oxide film 3 is selectively etched using the polyimide pattern 4 as a mask, and the electrode terminal structure of a semiconductor device is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to an improvement in a method for forming electrode terminals.

[Conventional technology]

FIG. 2 is a schematic cross-sectional view showing the steps of forming an electrode terminal in a conventional semiconductor device manufacturing method;
In the figure, 1 is an insulating film below the metal wiring, 2 is a metal pad such as aluminum or aluminum silicide formed on the insulating film 1, and 3 is a metal pad formed on the insulating film 1 and the metal pad 2 to prevent moisture from entering. A lower passivation film 4 is formed on the lower passivation film 3 to block ultraviolet rays and an upper passivation film 5a and 5b are formed on the lower passivation film 3 to absorb distortion of the molding resin, respectively. This is a resist film pattern for patterning 4.

Next, the manufacturing method will be explained.

First, a lower passivation film 3 is formed on the metal pad 2 formed on the insulating Ml, and a resist film 5a is further patterned on it (FIG. 2+8)).
Using this resist pattern 5a as a mask, the lower passivation film 3 is selectively etched, and the resist pattern 5a is selectively etched.
a (Fig. 2(b)).

Furthermore, an upper layer passivation film 4 is formed, and a resist pattern 5b is formed thereon (FIG. 2 (C1)).The upper layer passivation film 4 is selectively etched using the resist pattern 5b as a mask, and then the resist pattern 5b is formed. is removed to complete a series of processes, thereby completing the electrode terminal structure (FIG. 2(d)).

[Problem to be solved by the invention]

However, in the conventional method, the upper passivation film and the lower passivation film were patterned separately, so it was necessary to pattern the resist twice to form the electrode terminal structure. Furthermore, in the conventional method, the lower passivation film is etched and then the upper passivation film is etched, so the surface of the underlying electrode pad suffers double etching damage. In particular, when a corrosive liquid such as alkaline liquid is used to etch the upper layer film, the damage to the underlying electrode pad surface is significant, and such damage to the electrode pad surface can cause damage to the wire and metal pad during wire bonding later. This results in a decrease in the adhesion of the material, leading to problems such as increased adhesion resistance and wire peeling.

In this way, the conventional electrode terminal formation method uses the upper layer.

In addition to the problem of having to pattern the resist twice because the lower passivation film is patterned separately, the etching damage caused to the underlying metal pad surface is significant, reducing the reliability of the subsequent wire bonding process. There were also problems.

The present invention has been made to solve the above-mentioned problems, and it is possible to pattern the lower and upper passivation films using one resist mask, so that when forming electrode terminals, the underlying metal pad Aim to obtain a method for manufacturing a semiconductor device that does not cause damage to the surface 6 [Means for solving the problem] A method for manufacturing a semiconductor device according to the present invention includes a method for manufacturing a semiconductor device that does not cause damage to the surface when forming an electrode terminal. After sequentially forming a lower layer and an upper layer passivation film on the insulating film on which the metal pad is formed, the upper layer passivation film is selectively etched using the resist pattern as a mask, and then the lower layer passivation film is selectively etched using the upper layer passivation film as a mask. It is something to do.

[Effect]

In this invention, since the lower layer passivation film is etched using the upper layer passivation film as a mask,
A resist patterning process for etching the lower passivation film can be made unnecessary.

Furthermore, since the lower layer passivation film is etched after the upper layer passivation film is etched, the lower layer passivation film is on the electrode pad when the upper layer passivation film is etched, and the electrode pad is not exposed to the etching solution. Etching damage to the pad can be significantly reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view for explaining an electrode forming step in a method for manufacturing a semiconductor device according to an embodiment of the present invention;
In FIG. 1, 1 to 4 and 5b indicate the same components as in FIG. 2.

Next, the manufacturing method will be explained.

First, an electrode pad 2 made of aluminum silicide is formed on an insulating film 1 made of phosphorus glass, and then a silicon oxide film 3 serving as a lower passivation film is formed. Furthermore, a polyimide film 4 is formed as an upper layer passivation film, and then,
A resist pattern 5b is formed (FIG. 1(a)).

Using this resist pattern 5b as a mask, polyimide 4
After selectively etching with an alkaline solution, the resist pattern 5b is removed (FIG. 1(b)).

Furthermore, the silicon oxide film 3 is selectively etched using the polyimide pattern 4 as a mask to complete a series of processes, thereby completing the electrode terminal structure of the semiconductor device (FIG. 1(C)).

Here, when etching the silicon oxide film 3, which is the lower passivation film, using the polyimide 4, which is the upper layer passivation film, as a mask, the selectivity (etching rate of silicon oxide film/etching rate of polyimide) is sufficiently large.
It was confirmed that polyimide poses no problems as a mask for silicon oxide film etching. It was also confirmed that damage to the surface of the metal pad, which is aluminum silicide, was significantly reduced compared to the conventional method.

The pattern for passivation of the upper layer and the lower layer is basically a pattern in which only the electrode pad part and the dicing line part are opened, and usually the upper layer.

Considering the overlapping of the lower pattern, the opening width of the upper layer pattern is made larger than that of the lower layer pattern, but even if the lower layer film is etched using the upper layer pattern as a mask as in this example, there will be no problem with the pattern. Furthermore, in this embodiment, the lower passivation film 3 is etched using the upper passivation film 4 as a mask, so the pattern ends of the upper film and the pattern ends of the lower film are aligned, as shown in FIG. 1(e). Therefore, the cross-sectional shape of the electrode becomes a characteristic shape unique to this device.

According to this embodiment, after the upper passivation film 4 is patterned using the resist pattern 5b, the lower passivation film 3 is selectively etched using the upper passivation film 4 as a mask. It only needs to be etched once, which shortens the construction time and reduces costs. In addition, when etching the upper layer passivation film 4, the underlying metal pad is not exposed to the etching solution, which greatly reduces etching damage to the underlying metal band. As a result, effects such as improved adhesion between the wire and the metal pad and reduced adhesion resistance in the subsequent wire bonding process can be obtained.

In addition, in the electrode terminal structure of this example, since the pattern ends of the upper layer passivation film and the pattern ends of the lower layer passivation film are aligned, it is easy to detect edges when aligning the bonding position in the later wire bonding process. It can be performed with high precision, and
Since the end surfaces of the lower passivation film are flush, it is also possible to enhance the effect of suppressing moisture intrusion into the interior.

In the above embodiment, the lower passivation film was etched after removing the patterning resist film of the upper passivation film, but the lower passivation film was etched with the resist film left in place.
Thereafter, this resist film may be removed by etching, but in this case, the polyimide that is the upper passivation film must be heat-treated after the resist is removed.

〔Effect of the invention〕

As described above, according to the method for manufacturing a semiconductor device according to the present invention, when patterning both the lower and upper puffivation films that protect the insulating film in the lower layer of the metal wiring and the electrode metal pads on the surface of the insulating film, The upper layer passivation film is selectively etched using the resist pattern as a mask, and then the lower layer passivation film is etched using the upper nuclear layer pansivation film as a mask, so the resist patterning process only needs to be done once, shortening the construction period.

In addition to reducing costs, it is also possible to prevent the underlying metal pad from being damaged by etching when etching the upper layer passivation film, resulting in improved adhesion and adhesion between the wire and metal pad during the subsequent wire bonding process. This has the effect of reducing resistance, etc.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing a step of forming an electrode terminal in a method for manufacturing a semiconductor device according to an embodiment of the present invention, and FIG.
The figures are schematic cross-sectional views in order of steps showing a method of forming an electrode terminal in a conventional device. ■... Insulating film below metal wiring, 2... Gold i-pad serving as an electrode, 3... Lower layer passivation film, 4...
Upper layer passivation film, 5a, 5b...resist film. Note that the same reference numerals in the figures indicate the same or equivalent parts. Diagram

Claims (1)

[Claims] (1) In a method for manufacturing a semiconductor device including an electrode terminal forming step of forming an electrode terminal on an insulating film, the electrode terminal forming step includes forming an electrode metal pad on the insulating film, and then layering a lower layer and an upper layer over the entire surface. a first step of sequentially forming a passivation film; a second step of forming a resist pattern on the upper layer passivation film; and selectively etching the upper layer passivation film using the resist pattern as a mask; and then a second step of selectively etching the upper layer passivation film. a third step of selectively etching the lower passivation film using the mask as a mask.