JPH01129974A - Chemical vapor phase growing device - Google Patents

Abstract

PURPOSE:To form a growing film on a substrate with good coverage by arranging oppositely the substrate to be grown and a reactive gas injection head, and injecting inert gas in a showerlike state around the substrate from the circumference of the gas injection head in the growing reaction chamber of a CVD device. CONSTITUTION:A semiconductor substrate 2 is placed on a substrate stage 3 in the growing reaction chamber 1 of a CVD device and the inside of the reaction chamber 1 is evacuated through an evacuating port 6 and the substrate 2 is heated at 400-450 deg.C by heating the stage 3. Reactive passes such as SiH4, PH3 and O2 are blown on the substrate 2 through the gas injection head 5 opposed to the base plate 2 and thereby a phosphorus silicate glass film(PSG) is produced on the substrate by thermal decomposition of the reactive gasses with the temp. of the substrate 2. In this case, inert gas such as N2 is passed through a mesh plate 12 from the ceiling part of the reaction chamber 1 and injected in a showerlike state around the substrate 2 from the circumference of the gas injection head 5. The reactive gasses are inhibited from escaping from the outside of the substrate 2 by gaseous N2 flow and the PSG film is formed on the substrate 2 with excellent coverage.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of chemical vapor deposition equipment used in manufacturing semiconductor devices, the purpose of depositing a grown film with good coverage is to introduce a method in which a reaction gas is introduced into a growth reaction chamber. A gas injection head for injecting the gas and a substrate to be grown are arranged to face each other, and an inert gas is injected in a shower form from around the gas injection head to around the substrate to be grown. It is characterized by being made to grow by being injected into it.

[Industrial application field]

The present invention relates to improvements in chemical vapor deposition equipment used in manufacturing semiconductor devices.

In the wafer process for manufacturing semiconductor devices such as ICs, chemical vapor deposition equipment (CVD) is used.
2. Description of the Related Art Vapor Deposit (Al Vapor Deposit) apparatuses are used to grow insulating films and semiconductor films, and it is known that the adhesion state of the grown films has an extremely large effect on the quality of semiconductor devices.

[Conventional technology]

Figure 3 shows a schematic diagram of a conventional chemical vapor deposition apparatus, in which 1 is a growth reaction chamber (reaction chamber), 2 is a semiconductor substrate (
(Growth substrate), 3 is a substrate stage with a built-in heater, 4
5 is a reaction gas inlet, 5 is a gas injection head, and 6 is a vacuum exhaust port. That is, in this example, one semiconductor substrate is arranged,
This is a so-called single wafer type vapor phase growth apparatus capable of growing under reduced pressure.

For example, when coating the surface of a semiconductor substrate with a phosphorous silicate glass (PSG) film, monosilane (SiHa), phosphine (PH3), and oxygen (02) are introduced as reactive gases, and the substrate stage is heated. Heated for about 400 yen
The above-mentioned mixed gas is injected from the gas injection head 5 onto the surface of the semiconductor substrate heated to ~450°C, and thermally decomposed to form PS.
A G film is grown on the semiconductor substrate surface.

In addition to the PSG film, silicon oxide (Si02) was used as the growth film.
membrane, boron silicate glass (BSG) membrane.

An insulating film such as a phosphorus borosilicate glass (BPSG) film or a semiconductor film such as a polycrystalline silicon film is formed using a chemical vapor deposition apparatus as described above.

[Problem that the invention seeks to solve]

By the way, when growing such a grown film on a semiconductor substrate, it is important to grow it on the uneven substrate surface with as good coverage as possible, and as a guideline for the coverage, the side coverage ratio,
The terms bottom coverage ratio and aspect ratio are used, and will be explained with reference to FIG. That is, in FIG. 4, 7-1 is a substrate, 7-2 is an aluminum film, and 8
is a grown film, and 9 is a groove on the aluminum film surface.If the grown film is coated on the substrate surface with the groove 9 as shown in the figure, the groove 9 will be formed.
Adheres well to the inside and adheres well to the surface of the substrate. and,
If the thickness of the grown film on the substrate surface is a, the thickness of the grown film on the side surfaces of the groove is C, and the thickness of the grown film on the bottom of the groove is C, then b/aX1
00% is called the side coverage ratio, and C/aX 100% is called the bottom coverage ratio, and it is said that the larger this value is, the better the coverage is. Further, the aspect ratio is H/W when the depth of the groove is the width of the H2 groove bottom surface W, and it is fully expected that the coverage becomes worse as the aspect ratio increases.

FIG. 5 is a diagram explaining the problem of the conventional method. If a grown film is deposited with poor coverage, arched triangular nests 10 as shown in FIG. 5 will be included in the grooves 9. In this state, a growth film grows on the upper surface and the surface becomes flat. In this case, even if the deposited grown film (for example, a PSG film) is melted, the voids 10 remain unfilled, and the voids 10 expand and contract repeatedly due to temperature changes during IC operation, causing damage to the IC. This will damage its credibility.

Therefore, it is important to deposit the grown film with good coverage to prevent the formation of cavities, but it is difficult to grow with good coverage using the conventional chemical vapor deposition apparatus shown in FIG.

The present invention proposes a chemical vapor deposition apparatus aimed at eliminating such drawbacks and depositing with good coverage.

[Means for solving problems]

The purpose of this is to arrange a gas injection head for injecting a reaction gas and a growth substrate to face each other in a growth reaction chamber, and to inject an inert gas in a shower form from around the gas injection head to around the growth substrate. This is achieved by a chemical vapor deposition apparatus configured to perform growth by injecting a reactive gas onto the substrate to be grown.

[For production]

That is, the present invention provides a gas injection head and a growth substrate (
Growth is achieved by injecting a shower of inert gas around the semiconductor substrate (semiconductor substrate) and injecting a reactive gas from a gas injection head. In this case, the inert gas curtain suppresses the reaction gas from escaping to the outside of the growth substrate, thereby improving the coverage of the uneven substrate surface.

〔Example〕

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 shows a schematic diagram of a chemical vapor deposition apparatus according to the present invention, in which the same parts as in FIG. 3 are given the same symbols, and the other 11 is a nitrogen gas inlet.

12 is a mesh board. That is, the growth apparatus according to the present invention places the semiconductor substrate 2 in the same manner as the conventional apparatus.

The heated substrate stage 3 and the gas injection head 5 are placed opposite each other, and a reaction gas is sprayed onto the heated semiconductor substrate 2 to deposit a grown film. 5 and around the semiconductor substrate 2 in the form of a shower. In this way, the diffusion of the reaction gas to the surroundings outside the semiconductor substrate is suppressed by the nitrogen gas, and the nitrogen gas has a cooling effect to cool the gas injection head 5, etc., and as a result, the uneven substrate surface is Coverage is greatly improved.

For example, the conventional chemical vapor deposition apparatus shown in FIG.
The following is a comparison table of the coverage ratios of Examples in which the aspect ratio is 1 when a BPSG film or a PSG film is grown using the conventional chemical vapor deposition apparatus shown in the figure.

The growth conditions are a heating temperature of 410'C, a conventional device at normal pressure, and a device according to the present invention at a reduced pressure of 10 Torr.The reaction gases are monosilane (SiH4) and phosphine (PH3).
), diborane (B2H6), and oxygen (02), and the growth rate is 900 to 100 people/min.

Furthermore, nitrogen gas is used as the inert gas injected in the form of a shower in the growth apparatus according to the present invention, and therefore the exhaust system of the growth apparatus according to the present invention is large.

In addition, Figure 2 (a) and (b) are diagrams of the relationship between the side force coverage ratio and the aspect ratio when the aspect ratio is changed (Figure 2 (a)) and the relationship between the bottom surface coverage ratio and the aspect ratio. A relationship diagram (FIG. 2(b)) is shown, and in the data shown in FIG. 2, the curve 2 is the growth apparatus according to the present invention, and the curve 2 is the conventional growth apparatus.

Moreover, this data shows that when using a conventional growth apparatus at normal pressure,
In the growth apparatus according to the present invention, this value is when the pressure is reduced to about 10 Torr, but normally when the aspect ratio is large,
It is said that growing under normal pressure provides better coverage than under reduced pressure. However, the data shown in FIG. 2 shows that the reduced pressure of the growth apparatus according to the present invention yields better results than the normal pressure of the conventional growth apparatus. Therefore, it is clear that the chemical vapor deposition apparatus according to the present invention is very effective in improving coverage.

Note that although the above examples are data on results for insulating films containing phosphorus, it is generally said that films containing phosphorus have poor coverage, and therefore other insulating films that do not contain phosphorus or other semiconductor films may be used. It is clear that the coverage is even better.

〔Effect of the invention〕

As can be seen from the above description, the chemical vapor deposition layer according to the present invention significantly improves coverage, and has the effect of significantly contributing to improving the reliability and quality of semiconductor devices such as ICs.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a chemical vapor deposition apparatus according to the present invention, Figures 2 (a) and (b) are diagrams showing a comparison of coverage, and Figure 3 is a schematic diagram of a conventional chemical vapor deposition apparatus. , FIG. 4 is a diagram for explaining coverage, and FIG. 5 is a diagram for explaining conventional problems. In the figure, 1 is a growth reaction chamber, 2 is a semiconductor substrate, 3 is a substrate stage, 4 is a reaction gas inlet, 5 is a gas injection head, 6 is a vacuum exhaust port, 7-1 is a substrate, 7-
2 is an aluminum film, 8 is a grown film, 9 is a groove, 10 is a cavity, 11 is a nitrogen gas inlet, 12
indicates a mesh board. 1ff1.吋－搗・1\Moto Hashimoto and 1ΔAi ÷

Claims (1)

[Claims] In the growth reaction chamber, a gas injection head for injecting a reaction gas and a growth substrate are arranged to face each other, and an inert gas is injected in a shower form from around the gas injection head to around the growth substrate. A chemical vapor deposition apparatus characterized in that growth is performed by injecting a reactive gas onto the growth target substrate.