JPH1192280A - Silicon epitaxial vapor-phase growth apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon epitaxial vapor-phase growth apparatus for growing a single crystal film on a semiconductor silicon substrate (silicon wafer) by a vapor-phase epitaxial growth technique. SOLUTION: In this vertical type silicon epitaxial growth apparatus of high frequency heating method, the shape of a quartz bell jar 14 is made into an elliptical form and the upper spherical face of the bell jar is directly brought into contact with the inner peripheral face of a bell jar 13 made of stainless steel having the same curvature as that of the quartz bell jar to improve cooling effects. The quartz bell jar 14 is equipped with an opening part 18 so that a silicon substrate 17a can be automatically taken in and out of a reaction chamber without opening the reaction chamber to the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a silicon epitaxial vapor deposition apparatus for growing a single crystal film on a semiconductor silicon substrate (silicon wafer) by a vapor phase epitaxial growth technique.

[0002]

2. Description of the Related Art FIG. 3 schematically shows a conventional high frequency heating and vertical epitaxial growth apparatus. As shown in FIG. 3, a quartz bell jar 02 serving as a reaction chamber and a stainless steel bell jar 03 covering the outer periphery of the quartz bell jar 02 are provided above the stainless steel base plate 01. The inside of the stainless steel bell jar 03 is structured so that the inside can be shut off from the outside by an O-ring 04 at the bottom. The work coil is provided above the base plate 01 inside the reaction chamber.
5 at the center opening of the coil cover 06 in which
A susceptor rotation support member 08 rotated by the susceptor rotation means 07 is provided. The support member 0
The silicon substrate (silicon wafer) 010 is loaded on the carbon susceptor 09 installed in the position 8.
When loading and unloading the silicon substrate 010, the silicon substrate 010 is attached and detached in a state where the reaction chamber is largely opened by raising the stainless steel bell jar 03 by an up-down movement mechanism 011 for vertically moving the bell jar 03. ing.

[0003] A quartz bell jar 02 having the same hemispherical shape as that of the stainless steel bell jar 03 is attached to the inner wall of the stainless steel bell jar 03 by using an attachment fitting 012, and the corrosiveness introduced into the reaction chamber. It prevents corrosion by gas. In addition, a purge gas (hydrogen or nitrogen) 013 flows in a gap between the stainless steel bell jar 03 and the quartz bell jar 02 in order to cool the quartz bell jar 02 and to prevent intrusion of corrosive gas.

The susceptor 09 is induction-heated by a high-frequency work coil 05 provided below the susceptor 09, so that the silicon substrate 010 is also heated to a required temperature (1,000 to 1,1).
(50 ° C.), the epitaxial growth process is performed by the reaction gas 015 introduced through the quartz gas nozzle 014 through the center of the rotating susceptor 09, and the remaining gas 016 is naturally discharged through the exhaust unit 017. Exhausted. The above stainless steel bell jar 03
The inside is filled with cooling water 018 for cooling.

[0005]

However, the above-mentioned conventional apparatus has the following problems. Since the reaction gas 015 is introduced from one location in the center of the susceptor 09 and is naturally exhausted in the outer peripheral direction of the susceptor, when viewed from one wafer, upstream and downstream are formed with respect to the gas flow, For example, susceptor 09
However, there is a problem that even when is rotated, it is difficult to obtain uniformity of epitaxial growth in the inner and outer circumferential directions (that is, in the radial direction) of the susceptor. Here, quartz bell jar 0
Regarding the adhesion of the silicon compound to the inner wall, the adhesion starts when the quartz wall rises to a certain temperature or higher due to the heat rays from the susceptor 09, and the silicon compound adheres most particularly near the top of the quartz bell jar 02 where the heat rays are concentrated. The progress of adhesion and deposition can be slowed down as the temperature of the quartz wall is lowered. If the quartz wall is at a certain temperature or lower, this adhesion does not occur.

The quartz inner bell jar 02 is mounted on a stainless steel bell jar 0
However, at this time, there is a gap of 2 to 3 mm between both bell jars. For this reason, a large amount of purge gas 013 is supplied to perform heat transfer by gas from the wall of the quartz bell jar 02 to the wall of the stainless steel bell jar 03 cooled with water 018. Incidentally, when the gap between the two bell jars 02 and 03 is separated by several millimeters or more, the adhesion, deposition, and separation to quartz rapidly progress, making epitaxial growth practically impossible.

The silicon compound deposit 019 attached and deposited on the ceiling and the like in the above quartz bell jar 02
When the reaction chamber is opened when the silicon substrate 010 is attached or detached, it comes into contact with the outside air, an oxidation reaction proceeds, and it falls as silicon oxide or the like, and the particles fall into the silicon substrate 0.
Adhesion on 10 results in poor quality epitaxial wafers.

In the vertical reactor described above, a by-product of a silicon compound is generated by the decomposition reaction of the silicon source gas, and the by-product is deposited and deposited on the inner wall of the upper quartz bell jar 02 with time. When the temperature exceeds, the transparency of the quartz wall is lost and the susceptor 0
The heat rays from 9 heat this deposit, and the deposition of the silicon compound is further amplified. As this proceeds further, the deposit that has become too thick comes off and falls on the silicon substrate 010, As a result, there is a problem that the epitaxial growth process becomes impossible.

Although attempts have been made to automate the attachment and detachment of the silicon substrate 010 to and from the susceptor 09 using a robot, it is difficult to accurately detect the position of each substrate on the susceptor 09. There are problems such as the fact that the robot is inefficient and it takes too much time compared to humans, and the current situation is that automation of wafer handling has not been advanced.

As described above, the conventional high frequency heating type silicon epitaxial vapor deposition apparatus is insufficient in terms of securing product quality, improving productivity, reducing production costs, and automation.

In the present invention, an effective means for cooling a quartz bell jar is provided, a position for introducing a reaction gas is appropriately taken, a means for adjusting a gas flow rate on a susceptor is taken, and the reaction chamber is further opened to the atmosphere. An object of the present invention is to provide a silicon epitaxial vapor deposition apparatus having a much higher performance than before by employing an apparatus configuration means capable of automatically loading and unloading a silicon substrate without the need.

[0012]

According to a first aspect of the present invention, a reaction chamber is formed by disposing a stainless steel bell jar for cooling outside a quartz bell jar, and a reaction chamber is formed inside the reaction chamber. In a vertical silicon epitaxial vapor phase epitaxy apparatus in which a gas is introduced and epitaxial vapor phase epitaxy is performed on a silicon substrate by a high frequency heating method, the quartz bell jar is formed into an elliptical dome shape, and the quartz bell jar is provided on an outer periphery thereof. The bell jar is provided in close contact with the inner peripheral surface of the bell jar.

According to this structure, the quartz bell jar is in close contact with the stainless steel bell jar, so that the cooling effect is enhanced, the adhesion of the silicon compound is reduced, and the quartz bell jar is removed until it is necessary to take out and clean the quartz bell jar. The use of time becomes possible. In addition, since the quartz bell jar has a high cooling effect, the distance between the quartz bell jar and the susceptor can be reduced to about 1/2 or less compared to the conventional reaction chamber structure. And the consumption of high frequency power energy can be reduced. Further, since the reflection efficiency is increased and the upper surface of the silicon substrate can be kept at a high temperature, the occurrence of crystal defects and slip in the epitaxial film can be reduced.

According to a second aspect of the present invention, at least one reaction gas inlet is provided at an intermediate portion between the rotating susceptor heated by high frequency induction and the side wall of the quartz bell jar. And an exhaust unit is provided on the opposite side via the susceptor.

According to this configuration, by forcibly exhausting the gas in the reaction chamber from the exhaust portion, the flow rate of the reaction gas can be adjusted over the entire surface of the susceptor. Also,
Since there is no need to make a hole for introducing a reaction gas in the center of the susceptor as in the conventional case, the entire surface of the susceptor can be used efficiently, and processing of a large-diameter wafer can be easily dealt with.

According to a third aspect of the present invention, in the first aspect, the quartz bell jar is provided with an opening for taking a silicon substrate in and out, and a gate valve is provided on a side wall of the reaction chamber main body. Through the gate valve
A transfer chamber equipped with a robot for automatic insertion / removal of a silicon substrate is connected.

According to this configuration, the epitaxial process can be continuously performed while the reaction chamber is kept sealed from the outside air, the generation of particles due to oxidation of the silicon compound can be suppressed, and the intrusion of a contamination source from the outside can be prevented. .
In addition, the automatic transfer of the silicon wafer becomes possible, and the productivity can be dramatically improved by fully automating the operation of the apparatus.

[0018]

Embodiments of the present invention will be described below.

According to the present invention, in a vertical silicon epitaxial growth apparatus of a high frequency heating type, the shape of a quartz bell jar is made elliptical and its upper spherical portion is brought into direct contact with the inner peripheral surface of a stainless steel bell jar having the same curvature. By improving the cooling effect and providing the quartz bell jar with an opening, the silicon wafer can be automatically taken in and out of the reaction chamber without opening the reaction chamber to the atmosphere. Further, according to the present invention, by providing at least one reactive gas inlet at an intermediate portion between the susceptor and the side wall of the quartz bell jar, the reactive gas is uniformly supplied to the silicon substrate, and as a result, silicon growth on the silicon substrate is achieved. This is to improve the uniformity of the film.

According to the present invention, the usable time of the expensive quartz bell jar can be greatly extended, and at the same time, the generation of particles is suppressed, and the silicon substrate can be taken in and out without opening the reaction chamber as in the prior art. In addition, the reaction gas is evenly supplied to the entire surface of the silicon substrate, and the uniformity and reproducibility of the grown film is improved by adjusting the pressure in the reaction chamber to a constant value.
An apparatus capable of producing high quality epitaxial wafers with high productivity can be realized.

Further, according to the present invention, a gate valve for loading and unloading a silicon substrate is attached to the side wall of the reaction body, and a transfer chamber equipped with a robot for automatically inserting and removing a silicon substrate is connected via the gate valve. Therefore, in the high-frequency heating method, the epitaxial process can be continuously performed while the reaction chamber is sealed from the outside air.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings, but the present invention is not limited thereto.

[First Embodiment] FIGS. 1 and 2 are schematic views of the present embodiment. FIG. 1 is a plan sectional view, and FIG. 2 is an elevation sectional view.

As shown in FIGS. 1 and 2, the silicon epitaxial vapor phase epitaxy apparatus according to the present embodiment has an elliptical dome-shaped stainless steel bell jar 13 having a large curvature on the upper portion of the side wall 12 of the stainless steel reaction chamber 11. Is flange 1
An elliptical quartz bell jar 14 having the same curvature as that of the stainless steel bell jar 13 is directly adhered to the inner surface side of the stainless steel bell jar 13. The pressing of the quartz bell jar 13 to the stainless steel bell jar 12 is performed by pressing means 15 using a spring force such as a stainless steel bellows.
Is performed by directly pressing the quartz bell jar 13 against the inner surface of the stainless steel bell jar 11.
Cooling water W is introduced into the stainless steel bell jar 13 to cool the quartz bell jar 14 which is in close contact. The entirety of the stainless steel reaction chamber 11 is airtight so that the inside thereof can be evacuated by a vacuum means (not shown), and is shut off from outside air.

The curvature of the dome portion of the above-mentioned elliptical dome-shaped bell jar has a flat shape in the range of R200 to R350, and in this embodiment, the curvature is R300. In this way, by increasing the curvature in the elliptical shape, the distance between the silicon substrate 17 and the ceiling of the quartz bell jar is reduced to about 1/2 to 1/3 of the conventional spherical dome, and the silicon substrate 1
7, the heat reflection efficiency when heating is improved.

The quartz bell jar 14 is provided with a pressing means 15
The inner peripheral surface of the stainless steel bell jar 13 and the outer peripheral surface of the quartz bell jar 14 are in close contact with each other, but in order to further improve the cooling efficiency and prevent the intrusion of corrosive gas, these two are used. Bell jar 13,
Between 14, purge gas (hydrogen or nitrogen) from the top
16 are supplied. In addition, the quartz bell jar 14
An opening 18 is formed in the side wall of the silicon substrate 17 for taking in and out the silicon substrate 17.

The silicon substrate 17 is provided with the rotation support 1
9 and is mounted on a susceptor 21 rotated by a rotation mechanism 20. In this embodiment, only one sheet is shown for the sake of simplicity. However, it is also possible to increase the size of the entire apparatus and load a plurality of sheets as a large susceptor.

The susceptor 21 is high-frequency induction heated by a high-frequency work coil 23 covered by a coil cover 22 made of quartz.

The reaction gas 24 introduced into the reaction chamber is supplied onto the silicon substrate 17 through the quartz gas nozzles 25a and 25b, and the exhaust gas 26 is supplied to the nozzles 25a and 25b.
The gas is forcibly evacuated to a vacuum pump (not shown) through an exhaust port 27 facing the susceptor 17. Although two quartz gas nozzles are shown in the present embodiment,
One or several tubes may be used as necessary depending on the degree of gas supply.

The reaction chamber is made of a stainless steel bell jar 13.
And a stainless steel reaction chamber 11, and a space between the stainless steel bell jar 13 and the stainless steel reaction chamber 11 is formed by both flange portions 12a, 13a.
Are sealed by a vacuum-resistant seal 28 provided at the bottom. In the present embodiment, a box-shaped structure is shown for convenience, but a chamber structure having another shape such as a cylindrical shape may be used.

An opening 18 provided on the side wall of the quartz bell jar 14 is provided at one location of the side wall of the stainless steel reaction chamber 11.
An opening 29 for attaching the first gate valve 31 is provided at a position facing the first gate valve 31.
1, the silicon substrate 17 is loaded into the reaction chamber 11.
A transfer chamber 33 provided with a transfer robot 32 for unloading is provided. It should be noted that a purge gas is introduced into the transfer chamber 33 and keeps a state in which it is shut off from outside air.

In the transfer chamber 33, another second gate valve 34 is attached to a side wall facing the first gate valve 31, and a plurality of wafer cassettes are connected via the second gate valve 34. A load lock chamber (not shown) for accommodating is provided. In this embodiment, the vacuum chuck means 35 is used when the silicon substrate 17 is received. However, the present invention is not limited to this. For example, a known substrate support means such as a Bernoulli chuck may be used. It may be used.

The operation of the apparatus having the above-described configuration is performed according to the following procedure. (1) First, the second gate valve 34 is opened and the transfer robot 32 in the transfer chamber 33 receives one silicon substrate 17 from a wafer cassette (not shown) in a load lock chamber (not shown). This is carried into the transfer chamber 33.

(2) Next, the first gate valve 31 is opened, and the transfer robot 3 passes through the opening 29 of the stainless steel bell jar 13 and the opening 18 of the quartz bell jar 14.
2, the silicon substrate 17 is transferred onto the susceptor 21. When the transfer is completed, the robot arm of the transfer robot 32 is returned into the transfer chamber 33, and the first gate valve 31 is closed.

(3) Next, the susceptor 21
By 0, rotation is started, and at the same time, high-frequency power is applied to the high-frequency coil 23, and high-frequency heating of the susceptor 21 is started.

(4) When the temperature of the susceptor 21 rises to a predetermined temperature, the reaction gas 24 is supplied to the quartz gas nozzles 25a and 25a.
5b into the reaction chamber to start the epitaxial growth process.

(5) When the epitaxial growth process is completed, the supply of the reaction gas and the high-frequency power is stopped, and the susceptor 21 is immediately cooled.

(6) Susceptor 21 and silicon substrate 1
7, the first gate valve 31 is opened, the silicon substrate 17 after the reaction is taken out by the transfer robot 32, and is transferred to the wafer cassette in the load lock chamber via the second gate valve 34. Will be returned.

Thus, one cycle of the epitaxial growth is completed.

(7) As described above, after the first wafer is processed, the processing for the second wafer is similarly performed, and the processing for all the wafers in the cassette accommodated in the load lock is performed. The above cycle is repeated until is completed.

[0041]

The effects of the present invention are as follows. (1) Since the quartz bell jar is in close contact with the stainless steel bell jar and has a high cooling effect, there is little adhesion of a silicon compound, and it can be used for a long time until the quartz bell jar needs to be taken out and cleaned.

(2) Since the cooling effect of the quartz bell jar is high, the distance between the quartz bell jar and the susceptor can be reduced to about 1/2 or less as compared with the conventional reaction chamber structure. The efficiency of reflection of heat rays by the bell jar increases, and the consumption of high frequency power energy can be reduced. Further, the reflection efficiency is increased and the upper surface of the wafer can be kept at a high temperature, which leads to a reduction in crystal defects and occurrence of slip in the epitaxial film.

(3) Since it is not necessary to make a hole in the center of the susceptor, the entire susceptor can be used efficiently, and the processing of a large-diameter wafer (for example, 300 mm to 500 mm diameter) can be easily dealt with.

(4) Since the introduction of the reaction gas is performed not from the center of the susceptor but from the outside, the reaction gas is uniformly supplied to each wafer, and the uniformity of the epitaxial film is improved. Furthermore, by forcibly exhausting the introduced reaction gas from the opposite side of the susceptor, it is possible to prevent the reaction gas from staying in the reaction chamber for a long time, thereby reducing auto-doping and at the same time keeping the pressure in the reaction chamber constant. By maintaining the reduced pressure, the reproducibility of the epitaxial process can be improved.

(5) According to the structure of the reaction chamber of the present invention, a continuous epitaxial process can be performed while the reaction chamber is sealed from the outside air, so that generation of particles due to oxidation of the silicon compound is suppressed, and a contamination source from the outside. Intrusion can be prevented.

(6) The structure of the reaction chamber according to the present invention enables the automatic transfer of the silicon wafer, and the productivity can be remarkably improved by fully automatic operation of the apparatus.

(7) The productivity of the apparatus can be greatly improved by arranging a plurality of reaction chambers around the cluster system by making the wafer transfer chamber polygonal.

(8) The structure of the reaction chamber according to the present invention is as follows:
In addition to the silicon epitaxial growth process, for example, MO (METAL-ORGANIC: organic metal) -CVD (CHEMICAL VAPOR
DEPOSITON (chemical vapor deposition / growth) equipment can be applied in exactly the same way.

[Brief description of the drawings]

FIG. 1 is a schematic elevation view of a vertical silicon epitaxial growth apparatus of the present embodiment.

FIG. 2 is a schematic plan view of a vertical silicon epitaxial growth apparatus of the present embodiment.

FIG. 3 is a schematic view of a conventional vertical silicon epitaxial growth apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Reaction chamber made of stainless steel 12 Side wall 13 Bell jar made of stainless steel 14 Quartz bell jar 15 Pressing means 16 Purging gas 17 Silicon substrate 18 Opening 19 Rotation support 20 Rotation mechanism 21 Susceptor 22 Coil cover 23 High frequency work coil 24 Reaction gas 25a, 25b Quartz gas nozzle 26 Exhaust gas 27 Exhaust port 28 Vacuum resistant seal 29 Opening 31 First gate valve 32 Transfer robot 33 Transfer chamber 34 Second gate valve 35 Vacuum chuck means

Claims (3)

[Claims] 1. A reaction chamber is formed by disposing a stainless steel bell jar for cooling outside a quartz bell jar, and a reaction gas is introduced into the reaction chamber to epitaxially grow on a silicon substrate by a high frequency heating method. In a vertical silicon epitaxial vapor deposition apparatus, the quartz bell jar has an elliptical dome shape, and the quartz bell jar is provided in close contact with an inner peripheral surface of a stainless steel bell jar provided on an outer periphery thereof. Silicon epitaxial vapor deposition equipment. 2. The method according to claim 1, wherein at least one reaction gas inlet is provided at an intermediate portion between the rotating susceptor heated by high frequency induction and the side wall of the quartz bell jar, and the reaction gas inlet is opposite to the reaction gas inlet through the susceptor. A silicon epitaxial vapor deposition apparatus characterized in that an exhaust unit is provided in the apparatus. 3. The method according to claim 1, wherein an opening for taking in and out of the silicon substrate is provided on a side surface of the quartz bell jar, and a gate valve is provided on a side wall of the reaction chamber main body. A transfer chamber equipped with a robot for automatic insertion and removal of a substrate is connected to the silicon epitaxial vapor deposition apparatus.