JPH0544825B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a gas phase reaction apparatus for Si (silicon) wafers used in the semiconductor industry.

Conventional technology In recent years, in the semiconductor industry, cycle time,
There is a need to shorten the process.

An example of a conventional gas phase reactor will be described below with reference to the drawings.

FIG. 2 shows a conventional vapor phase growth apparatus. The quartz bell gear 1 and the base plate 2 can completely isolate it from the outside air, and the base plate 2 has a reaction gas supply port 3 for supplying the reaction gas and a reaction gas supply port 3 for discharging the reaction gas. A reaction gas outlet 4 is attached. Also base plate 2
A base 6 (hereinafter referred to as a susceptor) on which a semiconductor substrate 5 is placed is installed. Further, on the outside of the quartz bell gear 1, an infrared lamp 7 for heating the semiconductor substrate 5 and a reflecting mirror 8 are attached so that the reflected light of the infrared lamp 7 can efficiently irradiate the semiconductor substrate 5.

The operation of the gas phase reactor configured as described above will be explained below.

First, the semiconductor substrate 5 placed on the susceptor 6 is heated to a temperature of 600°C to
Heated to 700℃. A mixed gas of monosilane as a reaction gas and hydrogen as a carrier gas is supplied from the gas supply port 3 and discharged from the gas discharge port 4. The gas outlet 4 is directly connected to a vacuum pump (not shown), and the reaction chamber is maintained at a reduced pressure of several Torr. When the mixed gas supplied from the gas supply port 3 reaches the susceptor 6 heated to 600°C to 700°C, it absorbs heat and causes thermal decomposition, and as a result of the thermal field, the mixed gas is deposited on the semiconductor substrate 5. , polycrystalline silicon is estimated. (For example, the latest LSI process technology. Chapter 6 CLD technology) Problems to be solved by the Industrial Research Council invention However, in the above configuration, although the semiconductor substrate 5 is placed on the susceptor 6,
A phenomenon occurs in which the reaction gas also enters the gap between the semiconductor substrate 5 and the susceptor 6, and polycrystalline silicon is deposited on the back surface of the semiconductor substrate 5 as well. Therefore,
In the subsequent process of exposure in the darkroom process,
There is a possibility that the mask alignment will not be done properly and the yield will decrease.

Another problem is that although the quartz bell gear 1 also has a low light absorption rate, since it is heated, silicon accumulates on the inner surface of the quartz bell gear, making it difficult for infrared rays to pass through. Therefore, there was a problem in that a membrane with good reproducibility could not be obtained, and the quartz bell jar had to be cleaned every time a membrane was deposited.

In view of the above-mentioned problems, the present invention provides a gas phase reaction apparatus for producing a thin film with good reproducibility in which no polycrystals are deposited on a transparent quartz plate and no polycrystals are deposited on the back surface of a semiconductor substrate. This is what we provide.

Means for Solving the Problems In order to solve the above problems, the gas phase reaction apparatus of the present invention includes a support plate that has a hole smaller than the diameter of the semiconductor substrate and supports the semiconductor substrate, and a support plate that supports the semiconductor substrate. an upper reaction chamber equipped with a reactive gas supply port and a discharge port provided on the semiconductor substrate side, and a non-reactive gas supply provided on the side opposite to the upper reaction chamber, with the support plate as the boundary. A lower chamber comprising an opening, an outlet, and a light-transmitting plate provided opposite to the support plate, and an infrared lamp for radiant heating the semiconductor substrate through the plate, and an upper chamber. The pressure in the reaction chamber is a higher vacuum than the pressure in the lower reaction chamber.

Effect The present invention has the above-described configuration, and the lower chamber includes:
Since a non-reactive gas is flowing, even if the reactive gas from the upper reaction chamber flows in, it will be diluted, and a film will not be deposited on the back surface of the semiconductor substrate or the transparent quartz plate. Furthermore, since the pressure in the upper reaction chamber is higher than the pressure in the lower chamber, the non-reactive gas in the lower chamber flows into the upper reaction chamber through the gap between the support plate and the semiconductor substrate. As a result, the reaction gas in the upper reaction chamber will not flow into the lower chamber, and polycrystalline silicon will not accumulate on the semiconductor substrate, the back surface, or the transparent quartz plate.

Examples The following is a gas phase reactor according to an example of the present invention.
This will be explained with reference to the drawings.

In FIG. 1, a semiconductor substrate 9 is placed on a susceptor 10 coated with SiC and made of carbon. The susceptor has a sloped hole with a diameter slightly smaller than that of the semiconductor substrate. Further, the susceptor 10 is larger than the semiconductor substrate 9, and the susceptor 10 is larger than the semiconductor substrate 9.
The susceptor is placed on a susceptor support plate 11 having a diameter smaller than 0. The susceptor support plate is made of stainless steel. The reaction chamber is divided into two parts with the susceptor support plate 11 as a boundary, and the upper reaction chamber 12 has a reaction gas supply port 13 and a reaction gas discharge port 14 . The lower reaction chamber 15 has a non-reactive gas supply port 16
and a non-reactive gas outlet 17, and is further sealed with a transparent quartz plate 18. Shielding is done with an O-ring, and a lid 19 allows for complete hermetic shielding. The semiconductor substrate 9 is heated by light irradiation from an infrared lamp heater unit 20 consisting of an infrared lamp and a reflecting mirror. The outer wall of the reaction vessel 21 is made of stainless steel and has water cooling grooves 22 .

The operation of the gas phase reactor configured as above will be explained.

The semiconductor substrate 9 is heated to 600° C. to 700° C. by light irradiation from the infrared lamp heater unit 19. Monosilane gas is supplied to the upper reaction chamber 12 from a reactive gas supply port 13 and is discharged from a reactive gas discharge port 14, and hydrogen gas is supplied to the lower chamber from a non-reactive gas supply port 16 and is discharged from a non-reactive gas discharge port. It is discharged from 17. Each reaction chamber is evacuated by a vacuum pump (not shown), and the degree of vacuum in the upper reaction chamber 12 is set to be the same as or higher than the degree of vacuum in the lower reaction chamber 15. In this example, the degree of vacuum in the upper reaction chamber 12 is set to 2.
The degree of vacuum in the lower chamber was set at 2 Torr or 5 Torr. In this way, by flowing a non-reactive gas such as hydrogen or an inert gas into the lower chamber, even if the reactive gas flows from the upper reaction chamber 12, it is diluted and does not reach the point where a film is formed. Furthermore, by making the upper reaction chamber 12 a high vacuum,
Although there is a flow of hydrogen gas from the lower reaction chamber 14, the flow of monosilane gas from the upper reaction chamber 12 into the lower reaction chamber is almost negligible.

As described above, according to this embodiment, the upper reaction chamber 1
By making the degree of vacuum in the lower reaction chamber 15 higher than that in the lower reaction chamber 15, the reaction gas that absorbs heat and decomposes on the susceptor 10 reaches the semiconductor substrate 9 and deposits polycrystalline silicon. , does not flow into the back surface of the semiconductor substrate 9, and no polycrystalline silicon is deposited on the back surface. Furthermore, since no reaction gas flows into the lower reaction chamber 15, no film is deposited on the permeable quartz plate 18. As a result, infrared rays do not become easily transmitted, and a film with good reproducibility can be obtained. Further, the extra work of cleaning the transparent quartz plate 18 is eliminated, improving work efficiency.

In this embodiment, a polycrystalline silicon film is used, but it goes without saying that silicon oxide, silicon nitride, or any other film that utilizes a gas phase reaction can be used.

Further, although the susceptor 10 is made of carbon coated with SiC, the susceptor 10 may be made of any heat-resistant material that does not react with the reactive gas.

In addition, the susceptor support plate 11 and the reaction vessel 2
Although the outer wall of No. 0 was made of stainless steel, the outer walls of the susceptor support plate 11 and the reaction vessel 20 may be made of heat-resistant materials as long as they do not react with the reaction gas.

Further, although the transparent quartz plate 18 is made of transparent quartz, any material may be used as long as it is light-transmissive and heat-resistant.

Effects of the Invention As described above, there is a support plate for supporting the semiconductor substrate having a hole smaller than the diameter of the semiconductor substrate, and a reaction gas supply port and a discharge port provided on the semiconductor substrate side, bordering the support plate. an upper reaction chamber comprising: a non-reactive gas supply port and a discharge port provided on a side opposite to the upper reaction chamber with the support plate as a border; and a light-transmitting plate provided opposite to the support plate. and an infrared lamp for radiant heating the semiconductor substrate through the plate, and by making the pressure in the upper reaction chamber higher than the pressure in the lower reaction chamber, the back side of the semiconductor substrate can be heated. Furthermore, since there is no longer a film to be formed on the plate, and there is no longer a film to be deposited on the plate, there is no need to etch the back side of the semiconductor, and there is no need to clean the plate, making it possible to form thin films with good reproducibility. be able to.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a gas phase reactor according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional gas phase reactor. 9... Semiconductor substrate, 10... Susceptor, 11
... Susceptor support plate, 12 ... Upper reaction chamber, 1
3... Reactive gas supply port, 14... Reactive gas outlet, 15... Lower chamber, 16... Non-reactive gas supply port, 17... Non-reactive gas outlet, 18... Transparent quartz plate, 19 ... Lid, 20 ... Infrared lamp heater unit, 21 ... Reaction vessel, 22 ...
water cooling groove.

Claims (1)

[Claims] 1 Having a hole smaller than the diameter of the semiconductor substrate,
a support plate for supporting the semiconductor substrate; an upper reaction chamber bordering the support plate and having a reaction gas supply port and a discharge port provided on the semiconductor substrate side; a lower chamber consisting of a non-reactive gas supply port and a discharge port provided on a side facing the reaction chamber, and a light-transmissive plate provided opposite the support plate; and for radiant heating the semiconductor substrate through the plate. an infrared lamp, wherein the pressure in the upper reaction chamber is higher than the pressure in the lower reaction chamber.