JPS61174739A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the quality of a device by boring a recess in the case of forming an element separating region on the surface of a substrate covering the substrate and the side wall and bottom of the recess with an insulating film, making a poly-crystal Si layer adhere to only the above side wall and filling the poly-crystal Si into the recess, and thereafter converting the surface of the Si layer into an SiO2 film, thereby to stabilize the Si filling. CONSTITUTION:When an element separating region is formed on the surface of a substrate 1, firstly a recess 1a is bored and a non-crystallaine insulating film 1b made from Si3N4 or the like is made to adhere to the whole surface. Next, a poly-crystal Si film 5 is built up on the insulating film 16 and the film 5 is subjected to directional reactive sputter-etching, thereby to make the film 5 leave only on the insulating film 16 existing on the side wall of the recess 1a and remove the film 5 on the other portion. After that, a poly-crystal Si body 4 is filled in the recess 1a and subjected to heat-treatment, thereby to convert only the surface of the body 4 into an SiO2 film 6. In this way, portions except the filled portion are surrounded by the film 1b to stably secure the Si filling.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and in particular, to a method for manufacturing a semiconductor device, and in particular, to a method for manufacturing a semiconductor device, the present invention relates to a method for manufacturing a semiconductor device, and in particular, to a method for manufacturing a semiconductor device. The present invention relates to a method for filling polycrystalline materials into materials.

As semiconductor devices become more highly integrated, element isolation regions and capacitors formed on substrates are now formed in the form of grooves or holes, with depressions having an insulating film on their surfaces to reduce the area they occupy on the substrate. .

At this time, the recess is usually filled with polycrystalline silicon (Si) because of the need to stack other films on the substrate or because it is necessary to form an electrode on the inner surface of the recess in the case of a capacitor.

In order to ensure the quality of the semiconductor device, it is desirable that this filling can be performed in a stable manner.

[Conventional technology]

The procedure of an example of a conventional method for filling polycrystalline Si into the hollow of a substrate having a hollow and the surface including the hollow is made of an amorphous insulator is shown in FIGS. 2(a) to (C1). As shown in the step-by-step side sectional views.

That is, first [see figure (a)], the substrate 1 (1a is a depression,
1b is Si dioxide (SiO2) or Si nitride (Si3
A surface insulating layer made of an amorphous insulator such as Na)
A polycrystalline Si film 2 is grown thereon by chemical vapor deposition (CVD) using monosilane (SiHa) as a working gas until the recess 1a is filled. Polycrystalline Si film 2 is also grown on the upper surface of substrate 1.

Next [see Figure ('b)], a resist film 3 is formed by applying a resist on the polycrystalline Si film by a conventional method. Although the surface of the polycrystalline Si film 2 has irregularities, the surface of the resist film 3 becomes substantially flat.

Next, as shown in the figure (see C1), the resist film 3 and the polycrystalline Si film 2 on the substrate 1 are removed by an etching method with a small difference in etching rate between the resist film 3 and the polycrystalline Si film 2, such as sputter etching.

When the filling is completed, the polycrystalline Si body 4 remains in the depression 1a and the desired filling is completed.

The procedure of another example of the conventional method for filling the recess 1a with polycrystalline Si is as shown in the step-by-step side sectional view of FIG. 3 fa) (bl).

That is, first, a polycrystalline Si film 2 is grown in the same manner as in FIG.
is also grown on the upper surface of the substrate 1.

Next (see Figure fb), the polycrystalline Si film 2 on the substrate 1 is removed by mechanical polishing. Then, the polycrystalline Si body 4 remains in the depression 1a, completing the desired filling.

[Problem that the invention seeks to solve]

However, in the first example above, in Figure 2 (C1
During the etching mentioned above, it is difficult to determine the point at which the insulating layer 2 is exposed, so there is a problem that the reproducibility of the etching is poor.

Furthermore, in the second example, since it is difficult to match the polished surface with the top surface of the substrate 1, there is a problem that the thickness of the insulating layer 1b varies depending on the location on the top surface of the substrate 1.

These problems lead to a decline in the quality of semiconductor devices.

[Means for solving problems]

The above-mentioned problem is that in a substrate having a depression and a surface including a cough depression made of an amorphous insulator, after a polycrystalline film is deposited on the surface, the polycrystalline film is removed by leaving at least the side area of the depression. The problem is solved by the method of manufacturing a semiconductor device according to the present invention, in which the recess is filled with the polycrystalline material by selective vapor phase growth of the polycrystalline material using the polycrystalline film as a seed.

[Effect]

The removal of the polycrystalline film exposes the insulator on the top surface of the substrate, and the growth of the polycrystalline material selectively fills only the depressions using the polycrystalline film left in the depressions as a seed. Growth completes the desired filling.

Therefore, the above-mentioned etching and polishing are not necessary, and the conventional problems are solved.

In this way, it becomes possible to perform stable filling of the polycrystalline material into the hollows of a substrate whose surface including the hollows is made of an amorphous insulator, thereby improving the quality of semiconductor devices. It becomes possible to do so.

〔Example〕

Hereinafter, when filling polycrystalline Si into the hollow of a substrate having a hollow and the surface including the hollow is made of an amorphous insulator, the method of the present invention will be used to form an element isolation region filled with polycrystalline Si. The procedure of one embodiment will be explained with reference to step-by-step side cross-sectional views of FIGS.

That is, first of all, [see Figure (a)], if the amorphous insulating layer 1b of the substrate 1 in which the region where the element isolation region is to be formed is the depression 1a is made of Si3N4, a layer is placed directly on it (the figure shows this case). ), and when the insulating layer 1b is made of SiO2, an Si3N4 film (not shown) is deposited to a thickness of about 1000 mm using a normal method, and then a Si3 N4 film (not shown) is deposited to a thickness of about 100 to 2000 mm by CVD using, for example, SiH4 as a working gas. A polycrystalline growth film 5 of about 100% is grown. In this case, since SiH4 turns into Si and H2 to produce polycrystalline Si on the substrate 1, the polycrystalline Si film 5 grows to a substantially uniform thickness on the surface of the substrate 1 including the inner surface of the recess 1a.

Next, [see Figure ('b)], the polycrystalline Si film 5 is etched by directional reactive sputter etching using carbon tetrachloride (CC14'') as the working gas to form the insulating layer 1b (covered with the Si3N4 film). If the Si3
N4 film) is exposed. At this time, since the polycrystalline Si film 5 is thin, etching can be stopped at the point where the insulating layer 1b is exposed, and the reproducibility of etching is good. By this directional etching, the polycrystalline Si film 5 is etched onto the substrate 1.
The top surface and the bottom area of the recess 1a are removed to form the recess 1a.
lateral areas remain.

Next [see Figure (C)], polycrystalline S
Polycrystalline Si is selectively grown using the i film 5 as a seed. Then, the grown polycrystalline Si selectively fills the depression 1a to form the polycrystalline Si body 4, completing the desired filling.

This growth is caused by 5iHC13 and tI in the above CVD.
2 becomes Si and HCI to generate polycrystalline Si on the object to be processed (in this case, on the insulating layer 1b and polycrystalline Si film 5), and the generated Si reacts with HCI and reevaporates. The latter effect exists in existing polycrystalline Si.
This is achieved by taking advantage of the fact that Si is stronger on an amorphous insulator than above and selecting the temperature and pressure so that Si does not grow on the insulating layer Jb.

The working gas for the above CVD includes dichlorosilane (Si H2C12) or Si tetrachloride instead of 5iHC13.
(SiC1a) may be used, and hydrogen chloride (SiC1a) may also be used.
HC1) may be added as appropriate.

Next [see Figure (d)], when oxidation is performed by a normal thermal oxidation method, only the surface layer of Sr not covered with Si3N4, that is, the surface layer of the polycrystalline Si body 4, is oxidized, and the insulating layer 6 of 5i02 is oxidized.
is formed to complete the desired element isolation region.

The above-described polycrystalline Si filling method reduces variations in the thickness of the insulating layer 1b more than before even when the Si3N4 film is not deposited, and is effective in manufacturing the semiconductor device having the above-mentioned capacitor. It is easy to understand that this is also effective.

Furthermore, by using the same principle as the polycrystalline Si filling described above, the insulation Ff 1 b may be made of other amorphous insulators, such as amorphous alumina (A1zO3) (polycrystalline Si film 5
The polycrystalline Si body 4 is also made of other polycrystalline materials such as a tungsten (W) film grown by sputtering and W selectively grown using tungsten hexafluoride (WF6) and H2 as working gases. It is possible to do so.

〔Effect of the invention〕

As explained above, according to the method of the present invention, a polycrystalline substance can be filled into the hollow of a substrate having a hollow and the surface including the hollow is made of an amorphous insulator using a stable operation. This has the effect of making it possible to improve the quality of semiconductor devices.

[BRIEF DESCRIPTION OF THE DRAWINGS] In the drawings, FIG.
FIG. Cross-sectional view, Figure 3 (a
1(b) is a process order side sectional view showing the procedure of another example. In addition, in the figure, ① is a substrate, 1a is a depression, 1b is an amorphous insulating layer, 2.5 is a polycrystalline Si film, 3 is a resist film,
4 is a polycrystalline Si body, and 6 is an insulating layer. to fist 3

Claims (1)

[Claims] In a substrate having a recess and a surface including the recess made of an amorphous insulator, after depositing a polycrystalline film on the surface, removing the polycrystalline film leaving at least a side region of the recess, and then 1. A method of manufacturing a semiconductor device, comprising: thereafter performing selective vapor phase growth of a polycrystalline material using the polycrystalline film as a seed to fill the recess with the polycrystalline material.