JPH0584063B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for manufacturing semiconductor elements such as transistors and ICs, and more particularly to a technique for forming a base for a wiring pattern formed by aluminum vapor deposition or the like on the surface of a semiconductor element forming substrate.

B. Prior art Wiring patterns formed on the surface of semiconductor elements such as transistors and ICs are generally formed on an insulating film of SiO ₂ or Si ₃ N ₄ as a base, and the shape of the pattern becomes increasingly complex and dense. In line with this trend, the strength of adhesion to the substrate has recently become more and more important.

The first example of the form of the patterned wiring metal is
As shown in the figure, 1 is a silicon semiconductor substrate, 2 is an inorganic insulating film of SiO ₂ or Si ₃ N ₄ (hereinafter simply referred to as an insulating film) formed on the semiconductor substrate 1, and 3 is an insulating film 2 coated with a PR method. 4 is the silicon substrate m of the semiconductor substrate 1 exposed from the window hole 3.
A thin film wiring metal (pattern) formed on the surface n of the insulating film 2 in a desired pattern, usually made of Al
It is formed by vapor deposition or sputtering (ring). The manufacturing process up to the wiring metal 4 will be described with reference to FIGS. 2 to 6. First, as shown in FIG. do. Next, the resist 5 is selectively exposed and then developed to form a window 6 in a desired portion of the resist 5 as shown in FIG. Next, the insulating film 2 exposed through the window hole 6 is removed by etching to form a window hole 6 in the insulating film 2, and then the resist 5 is removed as shown in FIG. These figures 2 to 5
After the PR process is completed, if necessary, an Al vapor deposition film 4' shown in FIG. 6 is formed on the entire surface of the exposed substrate m of the semiconductor substrate 1 and the insulating film 2 by, for example, Al vapor deposition, and then
A predetermined pattern is selectively removed from the Al vapor deposited film 4' using the same PR method as described above to obtain the wiring metal 4 shown in FIG.

C. Problems to be solved by the invention In this way, most of the base of the wiring metal 4 is SiO ₂
or Si ₃ N ₄ insulating film 2, and the remaining base is a silicon base m formed as various electrode surfaces of semiconductor elements. formed with good adhesion. However, the wiring metal 4 on the insulating film 2
The adhesion is poor due to dirt on the surface of the insulating film 2, and PCT (current conduction test under high temperature and pressure) and HBT
During various reliability tests such as (tests in which bias is applied under high temperature) or during normal operation, the wiring metal 4 may partially peel off from the underlying insulating film 2 and lift up, causing accidents such as subsequent disconnection or accidents where the wiring metal 4 shoots into adjacent objects. This has become a factor that deteriorates the reliability of semiconductor devices. Such peeling of wiring metal is particularly common when the underlying insulating film 2 is Si ₃ N ₄ and the wiring metal 4 is Al, and it tends to increase more and more as wiring patterns become denser, so immediate improvement is required. Measures were required.

As a means of improving the adhesion between the insulating film 2 and the wiring metal 4, there is a method of activating the surface n of the insulating film 2 by plasma etching and then depositing Al, but this method requires expensive equipment. , and activation of surface n alone was insufficiently effective and impractical.

D. Structure of the Invention In order to solve the above-mentioned problems, the present invention provides that, before opening an insulating film on a semiconductor substrate using the PR method, the surface of the insulating film is subjected to a honing process using abrasive grains having etching properties different from those of the insulating film. Therefore, a manufacturing method is provided which includes a step of roughening the surface and a step of dissolving and removing the abrasive grains adhering to the insulating film with a chemical solution. The abrasive grains are suitably ultra-fine ones with a grain size of 1 μm or less, and the chemical solution is selected to dissolve the abrasive grains but not the insulating film.

E. Embodiments of the Invention Specific embodiments of the present invention will be sequentially described with reference to FIGS. 7 to 13.

In the honing process of the present invention, first, as shown in FIG. 7, abrasive grains 8 of fine metal powder are injected from a relatively moving nozzle 7 onto the surface n of the insulating film 2 formed over the entire surface of the semiconductor substrate 1. The surface n is sequentially roughened by spraying. The abrasive grains 8 may be commercially available products manufactured by a method such as rapid cooling of metal vapor such as Fe or Cu to solidify it into a powder having a particle size of 1 μm or less. By spraying the abrasive grains 8, the surface layer of the insulating film 2 is scraped into irregularities to form a rough surface n'. The roughness of this rough surface n' is variously controlled by the amount of abrasive grains 8, spraying speed, and spraying time. When the surface roughening treatment is completed, the abrasive grains 8 remaining attached to the insulating film 2 are removed. Since mere air blowing is not sufficient for this removal, the entire semiconductor substrate 1 is immersed in the next chemical solution 9 as shown in FIG. 8 to remove the attached abrasive particles, as shown in FIG. Dissolve grain 8. The chemical solution 9 dissolves only the abrasive grains 8. For example, the insulating film 2 is SiO ₂ and the abrasive grains 8 are Al.
In this case, a phosphoric acid solution is effective, and in a case where the insulating film 2 is made of Si ₃ N ₄ and the abrasive grains 8 are made of Cu, a hydrofluoric acid solution is effective. When the abrasive cleaning with the chemical solution 9 is completed, the entire semiconductor substrate is washed with water and dried, and then the PR process is carried out as in the conventional method.
Perform the wiring pattern creation process.

That is, first, as shown in FIG. 9, a resist 5 is applied to the entire surface of the insulating film 2, and then the resist 5 is selectively exposed and developed to form window holes 6 as shown in FIG.
After that, the insulating film 2 is etched from the window hole 6 to form a window hole 3 in the insulating film 2 as shown in FIG. In this PR process, the resist 5 is formed on the rough surface n' of the insulating film 2, so the adhesion between the two is stronger than that of conventional products without surface roughening.
Therefore, the probability that the etching solution will enter between the insulating film 2 and the resist 5 during the etching shown in FIG. 11 is reduced, and the dimensional accuracy of the window hole 3 becomes higher.

When the PR process is completed, the resist 5 is removed from the insulating film 2, and then the insulating film 2 is removed as shown in FIG.
For example, an Al vapor deposited film 4' is formed on the entire surface of the semiconductor substrate 1 exposed from the top and the window hole 3. Then, the Al vapor deposited film 4' is selectively removed by the PR method to form a desired wiring metal 4 as shown in FIG. The adhesion of the wiring metal 4 to the insulating film 2 is stronger than that of conventional products because it is formed on the rough surface n'. In particular, if the wiring metal 4 is formed by Al evaporation, the Al particles during evaporation will stick to the rough surface n' even with their high energy, resulting in stronger adhesion. In fact, when the wiring metal 4 is formed on the insulating film 2 whose surface has been roughened in this way, there is almost no problem of the wiring metal 4 peeling off and floating during reliability tests, etc., proving the effectiveness of the present invention. .

Incidentally, for the same purpose as the present invention, vapor metal fine powder abrasive grains 8
Instead, it is also possible to use inorganic abrasive grains with a particle size of about 10 μm, such as alumina, which is commonly used to roughen the surface of objects. However, the latter abrasive grains are undesirable because their grain size is too large, increasing the possibility that the insulating film 2 will be torn, making subsequent removal work difficult, and making complete removal difficult.

D. Effects of the Invention As described above, according to the present invention, the adhesion of the wiring metal to the underlying layer is further improved, so troubles such as wire breakage and shoots due to lifting of the wiring metal are reduced, and the yield of semiconductor manufacturing is improved and quality is improved. Improvements can be made.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional perspective view of a semiconductor device, FIGS. 2 to 6 are partial enlarged cross-sectional views of each process for explaining the conventional manufacturing method of the semiconductor device in FIG. 1, and FIGS. 7 to 13. 2A and 2B are partially enlarged cross-sectional views of the semiconductor device shown in FIG. 1 at various manufacturing steps according to the method of the present invention. 1... Semiconductor substrate, 2... Insulating film, 4... Wiring metal, 8... Abrasive grain, n'... Rough surface.

Claims (1)

[Scope of Claims] 1. A step of roughening the surface of an inorganic insulating film on a semiconductor substrate by honing using abrasive grains having different etching characteristics from that of the inorganic insulating film, and dissolving the abrasive grains attached to the inorganic insulating film with a chemical solution. A method for manufacturing a semiconductor device, comprising a step of removing the inorganic insulating film, and a step of selectively forming a wiring metal in a predetermined pattern on the inorganic insulating film. 2. The semiconductor device manufacturing method according to claim 1, wherein the abrasive grains are metal fine powder.