JPH02182883A - Chemical vapor deposition device by ultraviolet-ray excitation - Google Patents

Abstract

PURPOSE:To prevent cloudiness of quartz window glass and to enhance operation efficiency by providing a negative bias electrode to the quartz window glass part for permeating ultraviolet rays and providing a positive bias electrode to a susceptor part for holding a base plate and generating an electric field between both electrodes. CONSTITUTION:The semiconductor base plates 4 placed on a susceptor part 5 are arranged in a reaction chamber 22 and heated at the prescribed temp. by a heater 6. Furthermore a gaseous raw material such as SiH4 and NH3 is introduced into the reaction chamber 22 through an introduction port 7. This reaction chamber is exhausted to prescribed degree of vacuum through an exhaust port 9. The low-pressure mercury lamps 2 are arranged in a lamp chamber 21 adjacent to the reaction chamber 22 and the gaseous raw material is irradiated with ultraviolet rays through a quartz window glass 3. NH3 is decomposed to NH and NH<->, etc., by this light and an SiN film is formed on the base plate 4 by allowing them to react with SiH4. In the above-mentioned chemical vapor deposition device by ultraviolet-ray excitation, gas such as Ar is blown to the quartz window glass part 3 through an introduction port 8. Furthermore a mesh electrode 10 is provided and impressed to neagtive bias. On the other hand, an electrode 5a is provided to the susceptor 5 and impressed to positive bials. NH, etc., are attracted to the direction of the base plate 4 by the electric field formed between both electrodes and SiN is not formed on the window glass 3.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an ultraviolet excited chemical vapor deposition apparatus.

[Conventional technology]

Conventionally, this type of ultraviolet-excited chemical vapor deposition apparatus consists of a Lang chamber 21 and a reaction chamber 22, as shown in FIG. Ultraviolet light <f85nn) is irradiated from the lamp chamber 21 to the reaction chamber 22, and the light causes N H
s gas is decomposed to generate NH2-, NH, and SiH
4 and the semiconductor substrate (wafer) of the susceptor part 5.
5LNr on 4! It forms A.

On the other hand, in the reaction chamber 22, the intensity of ultraviolet rays is maximum at the quartz glass 3, so the reaction progresses intensely near the surface of the quartz glass 3, and the SiN film grows significantly on the quartz glass window.
Eventually, light will no longer pass through.

In order to prevent this, in the past, Ar was blown onto the quartz glass on the side of the reaction chamber 22 from the inlet 8, so that the reaction gas could be replaced with N.
MA ``Ex'' was to keep H3 and S i H4 away from the quartz glass.

[Problem to be solved by the invention]

In the conventional ultraviolet-excited chemical vapor deposition apparatus described above, in order to prevent the silica glass from fogging, a measure is taken to keep the growth gas away from the quartz glass by blowing Ar gas onto the quartz glass, as shown in Figure 3. However, it has the disadvantage that it cannot completely prevent fogging of quartz glass.

For this reason, after approximately 2 hours of SiN film growth, the window glass became cloudy and could no longer transmit enough ultraviolet rays to allow growth, and as a result, the continuous growth of the SiN film was limited to 2000 people.

An object of the present invention is to provide an ultraviolet-excited chemical vapor deposition apparatus that solves the above problems.

[Differences between the invention and the prior art]

In contrast to the conventional ultraviolet-excited chemical vapor deposition apparatus described above, the present invention creates an electric field between a quartz window glass section for transmitting ultraviolet rays and a susceptor for holding a semiconductor substrate, so that the growth is decomposed and ionized by ultraviolet rays. The difference is that the gas NH3 is drawn away from the quartz window glass and drawn towards the substrate.

[Means to solve the problem]

In order to achieve the above object, in the ultraviolet-excited chemical vapor deposition apparatus according to the present invention, the quartz window glass section for transmitting ultraviolet rays and the susceptor section for holding the semiconductor substrate each have electrodes. An electric field is generated between the two electrodes by applying a negative bias to the electrode and a positive bias to the electrode of the susceptor section.

〔Example〕

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

(Example 1) FIG. 1 is a sectional view showing a first embodiment of the present invention.

In the figure, a Lang chamber 21 and a reaction chamber 22 are arranged in upper and lower stages in the apparatus body 1, and the space between them is partitioned by a quartz window glass 3. A low-pressure mercury lamp 2 is installed in the Lang chamber 21, while the reaction chamber 22 is equipped with a susceptor section 5, an NH3/SiH4 introduction lower, an Ar introduction port 8, and an exhaust port 9.

The ultraviolet-excited chemical vapor deposition apparatus of the present invention has opposing electrodes 5a and 10 that create an electric field to move ions excited and decomposed by ultraviolet light away from the quartz window glass 3 and bring them closer to the semiconductor substrate (wafer) 11 to be grown. One electrode 5a is provided in the susceptor section 5, and the other electrode f! 10 near the quartz window glass 3, and a power source 1 is connected between the picture electrode 5a and 10.
1 are connected. Especially electrode 1 of quartz window glass 3
0 is made of metal mesh to transmit ultraviolet rays.

6 is a heater.

In the example, SiH4 and NH were introduced from the growth gas introduction lower
3 is introduced into the reaction chamber 22. NHs absorbs ultraviolet light emitted from the low-pressure mercury lamp 2 in the lamp chamber 21 through the quartz window glass 3, and is decomposed into NH2- or NH- and H+.

On the other hand, inside the reaction chamber 22, there is a mesh electrode 10 that is negatively biased by the power source 11 and a susceptor electrode f that is positively biased.
! An electric field is created by 5a, and NH2-, NH-
The ions are drawn toward the wafer 4 by the electric field, react with SiH, and grow a SiN film on the wafer 4.

(Example 2) FIG. 2 is a sectional view showing a second embodiment of the present invention.

In the first embodiment, the mesh electrode 10 is placed in the reaction chamber 220'!
! In this embodiment, the mesh electrode 10 is installed on the lamp chamber 21 side, and an electric field is formed by the mesh electrode 10 in the lamp chamber 21 and the susceptor electrode 5. Because of this, in Example 1, an electric field was formed only in the reaction chamber 22, but in Example 2, an electric field was formed in the lamp chamber 21 and reaction chamber 22, and the fogging of the quartz window glass 3 was prevented. The advantage is that it can be better prevented.

〔Effect of the invention〕

As explained above, in the present invention, by applying an electric field between the quartz glass and the wafer, the excited and decomposed growth gas can be attracted to the wafer side, and the film growth rate on the silica glass is 1/101 of that of the conventional method. This prevents the quartz glass from fogging up. t, because the amount of gas that grows on quartz glass is attracted to the wafer, S i NI
l! ! This has the effect of increasing the growth rate of I and increasing the maximum film thickness that can be grown without replacing the quartz glass to 2 μm or more, which is 10 times the conventional thickness.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a sectional view showing a second embodiment of the present invention, and FIG. 3 is a sectional view showing a conventional ultraviolet-excited chemical vapor deposition apparatus. 1... Device body 2... Low pressure mercury lamp 3...
- Quartz window glass 4... Semiconductor device 5... Susceptor part 5a... Susceptor electrode 10... Mesh electrode 11... Power supply 21... Lamp chamber 22... Reaction chamber Fig. 2 Figure 3

Claims (1)

[Claims] (1) The quartz window glass section for transmitting ultraviolet rays and the susceptor section for holding the semiconductor substrate each have electrodes, and the electrodes of the quartz window glass section are applied with a negative bias and the electrodes of the susceptor section are applied with a positive bias. An ultraviolet-excited chemical vapor deposition device that generates an electric field between two electrodes.