JPS622698B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor vapor phase growth apparatus in which the outside of a quartz bell gear is covered with a metal bell gear, and in particular, an observation window and a temperature sensor mounting structure for measuring the internal temperature with a radiation thermometer. It is related to.

As shown in FIG. 1, a vertical semiconductor vapor phase growth apparatus generally has a quartz bell gear 1 covered with a metal bell gear 2 made of stainless steel or the like, and a space between the lower part of the metal bell gear 2 and a base plate 3. A reaction chamber 4 is formed by keeping it airtight, and a wafer 5 is placed inside this reaction chamber 4.
A susceptor 6 on which a susceptor is placed and rotates at a low speed, a high-frequency induction heating coil 7 for heating the susceptor 6, and a nozzle 8 for ejecting reaction gas and etching gas are housed. It is necessary to control the temperature of the susceptor 6 and the wafer 5 thereon to a predetermined temperature suitable for the reaction. For this reason, conventionally, as shown in FIG. The temperature of the susceptor 6 and wafer 5 was measured by a radiation thermometer 10 installed at the wafer. The quartz bell gear 1 is supported by several supports 11 protruding from the inner surface of the metal bell gear 2, and since the gap between the bell gears 1 and 2 communicates with the reaction chamber 4, the observation window The opening 9 is hermetically closed with a transparent glass 12. Moreover, if the reaction gas from the nozzle 8 enters between the two bell gears 1 and 2, it may corrode the metal bell gear 2 or cause the quartz bell gear 1 and the transparent glass 12 to corrode.
In order to prevent reaction substances from adhering to the metal bell gear and clouding it, reducing the accuracy of temperature measurement, a gas inlet pipe 13 for supplying purge gas is connected to the upper part of the metal bell gear 2, and the space between both bell gears 1 and 2 is filled with the purge gas. By doing so, the reaction gas from the nozzle 8 is prevented from entering between the two bell gears 1 and 2, and furthermore, the branch pipe 14 is taken out from the gas introduction pipe 13 and the purge gas is sprayed onto the inner surface of the transparent glass 12. , this transparent glass 12 is more completely prevented from fogging. However, when the radiation thermometer 10 is placed far away from the metal bell gear 2 in this way, the temperature of the entire area of the susceptor 6 cannot be measured unless the observation window 9 is considerably widened, and if the observation window 9 is widened, it becomes cloudy. The area becomes wider and the degree of fogging also differs depending on the location, and after the amount of radiant heat from the heated susceptor 6 passes through the transparent glass 12, the result is partially different, resulting in an error. In FIG. 1, 15 is an exhaust port, 16 is a cooling pipe, and 17 is a hollow shaft that rotatably supports the susceptor 6.

The present invention was made in view of the above-mentioned points, and it is possible to more accurately measure temperature over a wide range with a smaller observation window, and more reliably prevent not only fogging but also heating of the transparent glass of the observation window. It is an object of the present invention to provide a semiconductor vapor phase growth apparatus in which the adverse thermal influence on a temperature sensor can be suppressed as much as possible.

The following Figures 2 to 3 show one embodiment of the present invention.
The diagram will be explained. 20 is the base plate,
A stainless steel metal cylinder 22 is placed on top of it via an O-ring 21 so as to maintain airtightness, and a metal bell gear 24 is placed on top of this metal cylinder 22 via an O-ring 23 so as to maintain airtightness. These are mounted and sealed by a clamp 25. 26 is a quartz bell gear, and 27 is a quartz cylinder, which are removably attached to the metal bell gear 24 and the metal cylinder 22 by several support pieces 28 and 29 that are removably attached to the lower ends of the metal bell gear 24 and the metal cylinder 22. Ready to be installed. 30 is a susceptor, 31 is a hollow shaft, 3
2 is a wafer, 33 is a nozzle, 34 is a high frequency induction heating coil, 35 is a cover made of quartz glass or the like, and 36 is an exhaust port. Said metal bell gear 24
An observation window 37 shown in detail in FIG. 3 is provided to project outward.

An annular flow path 39 surrounding the opening 38 is formed in the protrusion of the observation window 37, and a gas introduction pipe 40 for purging gas is connected to this annular flow path 39. The opening 38 is closed by a transparent glass 44 such as quartz glass attached to a lower cap 43 via O-rings 41 and 42. The annular flow path 39 is opened into the observation window 37 by a plurality of gas outlet ports 46 provided on the inner wall 45 of the observation window 37, and the gas outlet ports 46 supply the purge gas to the inner surface of the transparent glass 44. It is starting to erupt towards the enemy. The lower cap 43 has a through hole 47 in the center and a spherical seat 48 above it, and an upper cap 50 having a spherical seat 49 paired with this allows a spherical holder 51 to be mounted in a rolling and fixed manner. ing. A temperature sensor 52 of a radiation thermometer is engaged with the spherical holder 51 and fixed with a set screw 53 .

Next, the operation of this device will be explained. The wafer 32 placed on the susceptor 30 is heated by the high-frequency induction heating coil 34 via the susceptor 30 and is rotated by the rotation of the susceptor 30 driven via the hollow shaft 31.
Vapor phase growth is performed by reaction gas ejected from the reactor. The substances that have adhered to the inner surface of the quartz bell gear 26 and the surface of the susceptor 30 exposed between each wafer 32 due to this vapor phase growth are removed from the wafer 32.
It is removed and cleaned by taking it out and supplying etching gas from the nozzle 33. This etching gas does not sufficiently clean the adhered substances between the metal bellgear 24 and the quartz bellgear 26.

However, as mentioned above, both bell gears 24, 2
During the vapor phase growth operation, purge gas is supplied from the gas introduction pipe 40 between the two bell gears 24 and 26.
This prevents reactive gas from entering between the two.

The purge gas used in this device first flows from the gas introduction pipe 40 shown in FIG. made inside wall 4
The gas is ejected from the gas outlet 46 provided in the transparent glass 44 toward the inner surface of the transparent glass 44.
After flowing upward to wash away the inner surface of the bell gear 4, the liquid flows downward and flows between the two bell gears 24 and 26. Therefore, even if the reactive gas enters between the bell gears 24 and 26, the reactive gas will not enter into the opening 38 of the observation window 37, and the quartz glass on the inner surface of the transparent glass 44 and the portion facing it will not enter the opening 38 of the observation window 37. Keep the outer surface of the bell gear 26 clean. Therefore, the temperature of the susceptor 30 and wafer 32 can be measured more accurately by the temperature sensor 52.

Furthermore, the purge gas flowing through the annular flow path 39 and the observation window 37 has the effect of cooling the observation window 37, and in particular more effectively cools the transparent glass 44 that is heated by radiant heat. . Therefore, the heating of the temperature sensor 52 and its holding portion provided close to the transparent glass 44 is suppressed to a smaller level.

Furthermore, the temperature sensor 52 is connected to the upper cap 50.
By loosening the holder, the holder can be tilted as appropriate via the spherical holder 51, making it easy to measure temperatures over a wide range. Note that this temperature sensor 52 is made of transparent glass 4.
4, the amount of movement of the measuring axis X relative to the transparent glass 44 and the quartz bell gear 26 due to the tilting of the temperature sensor 52 is suppressed slightly. Therefore, the observation window 37 can be made smaller, which makes it possible to more reliably keep the area through which the measurement axis X passes clean.

The purge gas is supplied to both bell gears 2 in order to more reliably clean and cool the observation window 37.
Preferably, the entire amount supplied to 4, 26 is via the annular channel 39.

As described above, according to the present invention, temperature can be measured over a wide range with a smaller observation window, and temperature can be measured more accurately.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an example of a conventional semiconductor vapor phase growth apparatus, FIG. 2 is a schematic sectional view showing an embodiment of the same apparatus according to the present invention, and FIG. 3 is an enlarged detail of part A in FIG. 2. It is a diagram. 1, 26... Quartz bell gear, 2, 24... Metal bell gear, 5, 32... Wafer, 6, 30... Susceptor, 7, 34... High frequency induction heating coil,
8, 33... Nozzle, 9, 37... Observation window, 10
...Radiation thermometer, 12,44...Transparent glass, 1
3,40...Gas introduction pipe, 14...Branch pipe, 15,
36... Exhaust port, 39... Annular channel, 43... Lower cap, 46... Gas outlet, 50... Upper cap, 51... Spherical holder, 52... Temperature sensor.

Claims (1)

[Scope of Claims] 1. In a semiconductor vapor phase growth apparatus in which the outside of a quartz bell gear is covered with a metal bell gear, an observation window provided on the metal bell gear so as to protrude outward from the metal bell gear and having an opening closed with transparent glass; A temperature sensor is tiltably attached to the outer end of the observation window, an annular flow path is formed in the middle of the protrusion of the observation window from the metal bell gear, and a purge gas is supplied from the outside into the annular flow path. A semiconductor vapor phase growth apparatus comprising: a gas introduction pipe connected to supply purge gas; and a gas outlet for causing purge gas to flow out from the annular flow path into an observation window. 2. The semiconductor vapor phase growth apparatus according to claim 1, wherein the gas outlet is opened toward the inner surface of the transparent glass of the observation window. 3. The semiconductor vapor phase growth apparatus according to claim 1 or 2, wherein all of the purge gas supplied between the quartz bell gear and the metal bell gear passes through the annular flow path.