JPH03125154A - Production of semiconductor element - Google Patents

Abstract

PURPOSE:To prevent the chipping generated after application of photosensitive polyimide from being transferred onto underlying 1st, 2nd CVD films by applying the 1st photosensitive polyimide on the surface of a semiconductor device and drying the coating, then applying the 2nd photosensitive polyimide thereon so as to be thicker than the 1st photosensitive polyimide and drying the coating. CONSTITUTION:The 1st photosensitive polyimide 5a is applied relatively thinly on the surface of the semiconductor device 2 formed on a semiconductor substrate 1 and thereafter, the 2nd photosensitive polyimide 5b is thickly applied thereon. Then, even if the 1st photosensitive polyimide film is chipped, the chipping is filled with the 2nd photosensitive polyimide film and the probability that the chipping is generated in the same position of the 1st and 2nd photosensitive polyimide films is extremely lessened. The generation of the chipping is thus prevented and the transfer of the defects to th 1st, 2nd CVD films is prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention enables inspection of the underlying pattern of a photosensitive polyimide coating layer in a polyimide wafer coating process during the manufacture of semiconductor devices, and prevents through-holes. The present invention relates to a method of manufacturing a semiconductor device that enables the manufacturing of a semiconductor device.

(Prior Art) FIG. 3 is a cross-sectional view of a conventional polyimide wafer coating process. First, as shown in FIG.
After providing the AI bonding puff 2 on the substrate 1, the third
As shown in the figure (bl), the first CVD film 3, the 20th
On the semiconductor element on which llI4 was sequentially formed, photosensitive polyimide ll! A film is formed by spin-coding 5 to 6 to 10n.

At this time, defects 9 such as holes due to pattern defects may occur in the photosensitive polyimide film 5 due to attached dust, air bubbles, etc.

Next, as shown in FIG. 3 (FIG. 10), exposure 7 is performed using a negative mask 6 using an exposure machine (not shown) such as a reflection projection aligner.

Furthermore, a development process similar to the photoresist process is performed, and the photosensitive polyimide film 5 becomes an opening mask for the AI bonding pad 2, as shown in FIG. 3(d).

Next, as shown in FIG. 3(e), using an etching process, the second CVD film 4 is dry etched by RIE (reactive ion etching).

Next, the first cVD film 3 is wet etched, and A
I Expose the surface of the bonding puff 2 (Figure 3 [
) At this time, the missing tJ! caused by the spin code! Most of the first CVD film 3 formed by 9 is also etched.

Thereafter, the photosensitive polyimide film 5 is thermally cured by high-temperature treatment, and as shown in FIG. , the hole of the defect 9 generated during the spin cord becomes even larger in area due to thermal hardening.

Also, FIG. 4 tal to FIG. 4 (gl) are process cross-sectional views of another example of the conventional polyimide wafer coating process;
Figure 3 (The same parts as in the phrase are given the same reference numerals.

First, as shown in FIG.
After providing the bonding pad 2, as shown in FIG.
Spin code and form a film.

Next, as shown in FIG. 4(C), exposure 7 is performed using a positive mask 6a using an exposure machine such as a reflection projection aligner (not shown).

Furthermore, a development process similar to the photoresist process is performed, and the photosensitive polyimide film 5 is formed as shown in FIG. 4 Td+.
This serves as an opening mask for the AI bonding pad 2.

Next, using an etching process, as shown in FIG. 4(a), the second CVD film 4 is dry etched by RIB.

As shown in Figure 4(r), the first CvDll
! 3 is wet etched to expose the surface of the bonding band 2.

Thereafter, as shown in FIG. 4, the photosensitive polyimide film 5 is thermally cured by high temperature treatment to form a polyimide film 8 after heat curing, which becomes a semiconductor element surface protective film.

(Problem to be solved by the invention) However, in the phantom polyimide wafer coating process shown in Fig. 3+8) to Fig. 3, defects 9 such as holes generated after coating the photosensitive polyimide are exposed, developed, and etched. By this, the underlying first CVD film 3 and the second CVD film 3
The defect 9 is also transferred to Dlll&:, which adversely affects the semiconductor element.

In addition, in the polyimide wafer coating process shown in FIGS.
Generally, the surface tends to be brownish.

It is known that the cause of this brown color is that the photosensitizer changes due to high temperature treatment during heat curing.

When the photosensitive polyimide film 5 turns brown, there is a problem in that it becomes very difficult to inspect the underlying tuft.

The first aspect of the invention solves the problems of the above-mentioned prior art, and the first aspect of the invention is that the defects that occur after coating the photosensitive polyimide are the defects of the base layer. The present invention provides a method for manufacturing a semiconductor device that solves the problem that the image is transferred to the 20th VDH and has an adverse effect on the semiconductor device.

Furthermore, the second invention is a method for producing a semiconductor device that solves the problems of the prior art, including the difficulty in inspecting the underlying pattern due to the photosensitive polyimide film turning brown after high-temperature treatment. The present invention provides a method.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the first invention provides a method for manufacturing a semiconductor device in which a first photosensitive polyimide is formed into a relatively thin film on the surface of a semiconductor device formed on a semiconductor substrate. This method introduces a step of coating a second photosensitive polyimide in a thick film after coating.

In addition, in order to solve the above-mentioned problems, the second invention includes a step of sequentially applying a non-photosensitive polyimide and a photosensitive polyimide to the surface of a semiconductor device formed on a semiconductor substrate, and performing exposure and development to form a photosensitive polyimide. This method introduces a step of simultaneously removing the non-photosensitive polyimide in the area where the polyimide has been removed.

(Function) In the first invention, since the above-mentioned process is introduced in manufacturing the semiconductor element, even if a defect occurs in the first photosensitive polyimide film, the second photosensitive polyimide film can remove the defect. The defect is filled in, and these first. The possibility that the above-mentioned defects will occur at the same position in the second double photosensitive polyimide film is extremely reduced, and as a result, the problems caused by the above-mentioned defects can be eliminated.

Next, according to the second invention, the polyimide film has a two-layer structure to suppress the above-mentioned defect generation, and at the same time, the one-layer photosensitive polyimide film is removed in a predetermined pattern by exposure, and a development process is performed. Since the non-photosensitive polyimide film is removed in the area where the photosensitive polyimide film has been removed, the photosensitive polyimide film that causes the brown color is removed, which acts to suppress the tendency of the brown color, thus solving the above problem. Points can be removed.

(Example) Figure 1 (al to Figure 1 (hl) are process sectional views showing the first embodiment of the present invention, and Figure 3 (al to Figure 3 (1)
4(ar) to FIG. 4(gl) are described with the same reference numerals assigned to the same parts.

First, as shown in FIG. 1(a), a semiconductor element as a semiconductor device is formed on a Si substrate 1 as a semiconductor substrate, and an AI bonding bathode 2 is provided.

Next, as shown in FIG. 1 (bl), the first CVD film 3,
After sequentially forming the second CVD film 4, a thin film of the first photosensitive polyimide 5a is spin-coded by 1 to 2 microns.

In this case, the first photosensitive polyimide 5a is coated for 30 seconds at a spin code rotation speed of approximately 3200 revolutions, and the coating is performed at a viscosity of 3 voids.

Next, this first photosensitive polyimide 5a is dried on a known hot plate. At this time, it is assumed that a hole 10 occurs as a pattern defect.

Next, as shown in FIG. 1(C), the second photosensitive polyimide 5a is spin-coded so that it has a thickness of 4.84 mm thicker than the first photosensitive polyimide.

In this case, the spin code number is approximately 3000 revolutions, coating is performed for 30 seconds, and the viscosity is 10 voids.

After applying the first photosensitive polyimide 5a as the lower layer, when applying the second photosensitive polyimide 5b as the upper layer, when dropping the second photosensitive polyimide 5b, the first photosensitive polyimide 5
a is dissolved, and the second photosensitive polyimide 5b in the dropped portion becomes a thin film part 11, which causes variations in film thickness. ing.

Further, the spin rotation speed of the first photosensitive polyimide 5a in the lower layer and the second photosensitive polyimide 5b in the upper layer during spin coding is preferably about 3000 to 4000 rotations. When setting the film thickness of the polyimide 5b, it is impossible to use the same viscosity, so the viscosity and spin rotation speed are set as described above.

After coating the second photosensitive polyimide 5b as the upper layer in this manner, the second photosensitive polyimide 5b is dried at about 100° C. using a known hot plate.

At this time, the holes 10 generated during the spin-coding of the first photosensitive polyimide 5a are filled, and the holes 10 generated during the spin coding of the first photosensitive polyimide 5a are
A thin film portion 11 is formed.

Next, as shown in FIG. 1 (dl), exposure 7 is performed in a predetermined pattern using a negative mask 6 and an exposure machine such as a reflection projection aligner, and as shown in FIG. The films of the first photosensitive polyimide 5a and the second photosensitive polyimide 5b are removed in a predetermined pattern.

Furthermore, as shown in FIG.
Dry etching using (reactive ion etching).

Furthermore, as shown in FIG. 1 (phantom), the first CVD film 3 is wet-etched to expose the AI bonding pad 2, and then, as shown in FIG. The polyimide is heat cured to form polyimide 12 after heat curing, which becomes a surface protective film of a semiconductor device.

As described above, according to the first embodiment of the present invention, the first photosensitive polyimide 5a is applied as a relatively thin film, and the second photosensitive polyimide 5b is further applied as a thick film on top of this, resulting in two layers. By adopting this structure, it is expected that the possibility of defects occurring at the same position above and below in the upper and lower polyimide films will be extremely reduced, and holes 10 that will cause film defects in the first photosensitive polyimide 5a of the upper layer will be eliminated. can.

2(al) to 2(hl) are process sectional views of the second embodiment of the present invention, and the same parts as in FIG. 1(al to 1(hl) will be described with the same reference numerals.

First, as shown in FIG. 2 (al), a semiconductor element as a semiconductor device is formed on a Si substrate l as a semiconductor substrate, and an AI bonding bathode 2 is provided.

Next, although it is not shown in Figures 2-), Figure 2(c)
After sequentially forming the first CVD film 3 and the twentieth VD film 4, as shown in FIG.

As shown in FIG. 2(c) again, the non-photosensitive polyimide 1
After coating No. 3, a photosensitive polyimide 14 of 1 to 2 μm is spin-coded and dried at about 100° C. on a hot plate.

Next, as shown in FIG. 2(dl), exposure 7 of a predetermined pattern is performed using a positive type mask 6a using an exposure machine such as a reflective progeexicon aligner.

Furthermore, as shown in FIG. 2(e), a development process similar to the photoresist process is performed. At this time, since the non-photosensitive polyimide 13 is non-photosensitive and cannot be patterned with a normal polyimide developer, it is simultaneously dissolved. This is done using any available developer.

By performing exposure and development in this manner, the non-photosensitive polyimide 13 and the photosensitive polyimide 14 are removed in a predetermined pattern.

Next, as shown in FIG. 2 (fl), using an etching process, the second CVD film 4 is dry etched by RIE.

Furthermore, as shown in FIG. 2, the first CVD film 3 is wet-etched to expose the bonding pad 2.

After that, the non-photosensitive polyimide 13 was heated to 300°C to 400°C.
After heat curing, polyimide 12 is formed, which is used as a protective film on the surface of a semiconductor device.

As described above, according to the second embodiment, by the two-layer coating process of the non-photosensitive polyimide 13 and the photosensitive polyimide 14,
It is expected that by leaving only the non-photosensitive polyimide 13 and removing the photosensitive polyimide 14 and treating it at high temperature, the tendency to turn brown will be suppressed and the underlying pattern etc. can be easily inspected.

In addition, when photosensitive polyimide 14 is used for pattern formation, the amount of film loss varies during the subsequent etching process.
This is because even if a portion of the photosensitive polyimide 14 remains, there is no problem in terms of film properties.

However, when photoresist is used, it is necessary to completely remove the resist, which makes it difficult to control the remaining film thickness. .

The brown discoloration of the polyimide described above is mainly due to the photosensitive polyimide. Since such photosensitive polyimide remains as a protective film, the above-mentioned inspection problem arises.

Therefore, as specifically explained in the second embodiment, the thickness is preferably such that all of the photosensitive polyimide in the upper layer is removed during the exposure and etching steps so as to avoid the disadvantages caused by the brown discoloration described above.

However, on the other hand, in order to prevent through holes by multilayering the protective film as in the first embodiment, a two-layer film with remaining photosensitive polyimide is suitable.

For these reasons, it is necessary to take measures to reduce the influence of brown discoloration of photosensitive polyimide to a level that allows inspection of the amount of discoloration depending on the film thickness range.

With these, the effects of solving the above-mentioned through-hole problem and inspection problem can be achieved at the same time.

(Effects of the Invention) As described above in detail, according to the first invention, the first photosensitive polyimide in the lower layer is made into a thin film, and the second photosensitive polyimide in the upper layer is made into a thick film. Even if a defect occurs in the first photosensitive polyimide during drying of the first photosensitive polyimide, the defect is filled in by applying the second photosensitive polyimide, so that the occurrence of the defect can be prevented. It is possible to prevent defects from being transferred to the second CVD film.

Further, according to the second invention, after applying non-photosensitive polyimide to the surface of the semiconductor device on the semiconductor substrate, applying photosensitive polyimide, drying, exposing and developing, and turning the surface brownish by high temperature treatment. Since the photosensitive polyimide that exhibits a tendency to brown is removed and only the non-photosensitive polyimide is left, the brownish tendency can be suppressed and the underlying pattern can be easily inspected.

[Brief explanation of the drawing]

1 fat to 1 fhl are process sectional views of the first embodiment of the method for manufacturing a semiconductor device of the present invention, and FIG.
2 through 2 fhl are process cross-sectional views of the second embodiment of the semiconductor device manufacturing method of the present invention, and 3 (al through 3 (gl and 4 +8) through 4 tg'+ are respectively It is a process cross-sectional view of a conventional manufacturing method of a different semiconductor element. 1... Si substrate, 21... AI bonding pad, 3... First CVD film, 4... Second CVD film, 5 a - first photosensitive polyimide, 5b... second photosensitive polyimide, 6... negative mask, 6a... positive mask, 10... hole, 12... polyimide after thermosetting, 13...Non-photosensitive polyimide, 14...Photosensitive polyimide.

Claims (2)

[Claims] (1) (a) After applying a first photosensitive polyimide to the surface of a semiconductor device formed on a semiconductor substrate and drying it, apply a second photosensitive polyimide so that the film is thicker than the first photosensitive polyimide. and (b) exposing and developing the first and second photosensitive polyimides in a predetermined pattern. (2) (a) A step of applying non-photosensitive polyimide to the surface of a semiconductor device formed on a semiconductor substrate, and then applying and drying the photosensitive polyimide; (b) a step of applying the photosensitive polyimide and the non-photosensitive polyimide; (c) removing the non-photosensitive polyimide at the same time in the areas where the photosensitive polyimide has been removed by exposing and developing the polyimide in a predetermined pattern; A method for manufacturing a semiconductor element, comprising: drying the surface of the semiconductor device to form a surface protective film for the semiconductor device.