JPH0628243B2 - Metalorganic vapor phase growth equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crystal growth apparatus by a metal organic chemical vapor deposition method, and in particular, a large number of high quality crystals are obtained by eliminating the intrusion of moisture and oxygen from the outside. The present invention relates to a device capable of growing one at a time.

[Prior Art] When growing a semiconductor single crystal layer, an epitaxial growth method for growing a semiconductor crystal layer on a semiconductor substrate is widely used. Among these epitaxial growth methods, the metal organic vapor phase epitaxy (hereinafter abbreviated as MOVPE) has attracted attention.

This is because an organometallic gas such as trimethylgallium (Ga (CH ₃ ) ₃ ) or triethylaluminum (Al (C ₂ H ₅ ) ₃ ) and arsine (AsH ₃ ) or phosphine (PH ₃ ) are used as raw materials, and they are heated. This is a method of decomposing and epitaxially growing.

The MOVPE method is said to be capable of precise control and suitable for mass production, and has come to occupy an important position in semiconductor manufacturing technology.

The characteristics of the epitaxially grown layer manufactured by the MOVPE method are strongly influenced by the atmosphere inside the growth apparatus. That is, when manufacturing a semiconductor product containing a component that easily oxidizes, such as aluminum or antimony, oxygen and moisture may cause
If it remains in the PE device even a little, there is a problem that the characteristics are significantly deteriorated. Therefore, the amount of oxygen and water is M
Conventionally, some measures have been taken to prevent invasion into the OVPE growth apparatus.

[Problems to be Solved by the Invention] As a means for preventing the invasion of oxygen and moisture, a leak-tight structure is formed by welding the joint portion of the pipe or changing the growth chamber itself from quartz to stainless steel. A method has been adopted in which a preparation chamber that can be evacuated to vacuum is provided, and a semiconductor wafer is passed through the preparation chamber and loaded into a growth chamber.

In particular, the method of providing the vacuum preparation chamber is effective. But,
In the conventional device, only one semiconductor wafer can be loaded, and in the mass production type multiple wafer simultaneous growth type device, there is no one equipped with a preliminary chamber, and the transfer mechanism contacts the surface of the growing semiconductor wafer. However, if a force is applied to the surface, the surface may be damaged, and good epitaxial growth may not be possible. The transportation is not easy, and it is difficult to provide the vacuum preparation chamber. Under such circumstances, it has not been easy to grow a high-quality semiconductor epitaxial crystal containing Al or the like, which is easily oxidized, with good reproducibility using a conventional mass-production type device.

[Advantages of the Invention] The present invention has been made in view of the above problems, and provides a mass-production type metal-organic vapor phase epitaxy apparatus capable of preventing invasion of moisture and oxygen from the outside and growing a high-quality epitaxial crystal. It is intended to be provided.

The device of the present invention is basically a conventional vertical type mass production type MOVP.
A vacuum preparation chamber, which was not included in the E apparatus, is provided above the growth chamber, and a semiconductor wafer transfer mechanism is further provided in the growth chamber to configure the growth apparatus.

The present invention will be described below with reference to the embodiment shown in FIG. As shown in the figure, the basic configuration of the present invention is based on the upper transport mechanism 1.
And an intermediate vacuum preparation chamber 2 and a lower growth chamber 8.

The carrier 1'of the semiconductor wafer carrier mechanism 1 vertically penetrates the intermediate vacuum preparation chamber 2 by power, and further, the gate valve 6
Can be penetrated to reach the periphery of the lower susceptor 9.

The vacuum preparation chamber 2 is provided with a door 5 on one side for loading and unloading the wafer holder 7, and is connected to the vacuum preparation chamber exhaust system 3 by a pipe. At the bottom of the vacuum preparation chamber 2, a wafer holder cassette rail 18 is laid in a straight line from the door entrance with a pipe hole 19 reaching the gate valve 6 in between. On top of this, a holder cassette for mounting wafers equipped with wheels
17 can be placed, but this wafer holder cassette 17 is
A plurality of wafer holders 7 mounted with the semiconductor wafers 12 mounted thereon are provided with holding portions 20 that do not touch each other and the surfaces of the semiconductor wafers 12 do not touch each other, and on the rail 18, left, The pipe hole 19 reaching the gate valve 18 in the middle is designed so as not to be blocked by the end portion of the wafer holder cassette 17 when it is at either end position on the right. The vacuum preparation chamber 2 is separated from the growth chamber 8 by a gate valve 6.

The wall surface of the growth chamber 8 installed below the gate valve 6 forms a so-called vertical growth chamber and is made of stainless steel. The portion heated up by heating has a double wall structure, the cooling water inlet 10 is provided below this double wall structure portion, the cooling water outlet 11 is provided above it, and the growth chamber 8 grows at its lower part. It is connected to the chamber exhaust system 15 by a pipe and receives the source gas from the source gas supply system 4, so that it is connected to the source gas supply system 4 at the top of the growth chamber 8 by a pipe. This growth room 8
The inside of the top of the susceptor 9 and the surface of the susceptor 9 facing the inside are
As will be described later, it is formed in a shape such that the raw material gas flow is not disturbed when the wafer holder 7 is mounted.

The rotary susceptor 9 is supported by a susceptor rotating mechanism 13 so as to be vertically rotatable, and a resistance type heater 16 for heating the wafer 12 is disposed inside the susceptor 9 and is connected to a heater current introducing terminal 14.

In this embodiment, the wafer holder cassette 17 is formed so as to hold eight wafer holders 7, and the susceptor 9 has a mounting portion on its side surface on which four wafer holders 7 can be mounted. The reason for this is that when the number of wafer holders 20 mounted at one time in the susceptor 9 of the growth chamber 8 is set to 20 or more and the epitaxial growth is completed for the four wafer holders 7, the number of holding portions 20 is increased. The wafer holder 7 which is pulled up and held in the empty holding portion of the wafer holder cassette 17 in the vacuum preparation chamber 2 is immediately put on standby without lowering the door 5, and the wafer holder 7 for non-epitaxial growth processing is lowered and mounted on the susceptor 9, This is because the epitaxial processing is started. Of course, the number of wafer holder cassettes 7 may be the same as the number of wafer holders 9 to which the susceptor 9 can be attached.

When the rod-shaped carrier 1'passes through the gate valve 6 and descends into the growth chamber 8, the wafer holder 7 suspended at the tip thereof.
The susceptor 9 so that it slides into a downwardly projecting inclined recess formed on the outer periphery of the susceptor 9.
While it is in contact with the surface of, it descends and fits into the recess.

Now, in the state shown in the figure, the leftmost wafer holder 7 is placed in the growth chamber 8
To set the wafer holder cassette 17 to the susceptor 9, the susceptor 9 is rotated, the mounting portion of the vacant wafer holder 7 of the susceptor 9 is positioned directly below the gate valve 6, and the wafer holder cassette 17 is moved slightly to the left. The cassette 17 is connected to the tip of the carrier 1'and pulled up a little, the wafer holder cassette 17 is retracted to its original position, and the carrier 1'is lowered with the gate valve 6 opened to lower the wafer holder 17 '. To the susceptor 9. By repeating this operation in sequence, the wafer holder 7 can be set in the recesses of all the mounting portions of the susceptor 9. When the wafer holder 7 is pulled up to the vacuum preparation chamber 2, the wafer holders 7 that have been processed are sequentially opened from the holding portion 20 of the wafer holder cassette 17 farther to the hole 19 communicating with the gate valve 6 in the figure.
Set over the holding portion 20 close to.

Next, although not shown, when there is an unprocessed wafer holder 7, the entire cassette 17 is moved to the left rail 18, the above operation is repeated, and finally when all the processing is completed, in this embodiment, The eight processed wafer holders are on the wafer holder cassette 17 and are pulled out of the door 5 through the door 5 with the gate valve 6 closed.

Before and after, the unprocessed wafer holder 7 is held in the wafer holder cassette 17 and put into the vacuum preparation chamber 2 and then independently evacuated to a vacuum by the exhaust system 3, and the outside air and the wafer and Oxygen and moisture adsorbed on the wafer holder are removed. The gate valve 6 is opened, and the wafer holder 7 is sequentially set on the susceptor 9 by the transfer mechanism as described above.

As described above, in order to carry the wafer holder 7 by the carrier 1 ′, the carrier, the wafer holder and the holding operation will be specifically shown in FIGS. 2A, 2 </ b> B and 2 </ b> C. At the bottom of the wafer holder 7, there is provided an insertion hole 19 into which a projection 20 formed by bending the tip of the carrier 1'into an L shape can be inserted.
Since the carrier 1'can be configured to move up and down as shown by an arrow and to rotate, the protrusion 20 is inserted into the insertion hole 19 and held at a predetermined position (recess) of the susceptor 9, and the Can be transferred to the spare room.

In the example shown in FIG. 3, a hole 21 is provided in the lower portion of the wafer holder 7, and a protrusion 22 is provided in the lateral direction of the tip of the carrier 1'for connecting and releasing the hole. In any case, if any chuck mechanism for the wafer holder is provided on the wafer holder 7, dust is generated when the chuck mechanism operates and adheres to the wafer surface to cause defects on the epitaxial growth surface. Thus, the lower part is desirable so that the effect is as small as possible.

Next, the gate valve 6 is closed and the growth process is started.

Accurately controlled TMG, AsH from the source gas supply system 4
A raw material gas such as ₃ is guided by the heater 16 to the surface of the semiconductor wafer 7 heated to a predetermined temperature, for example, 600 to 700 ° C., thermally decomposed and epitaxially grown. In this embodiment, it is possible to grow under reduced pressure by the vacuum exhaust system 15. After the growth is completed, AsH ₃ is flown up to about 400 ° C., for example, in the case of GaAs growth, and when the temperature becomes lower than that, the gas is exhausted from the vacuum exhaust system 15. After that, the above-described procedure is reversed to collect the grown wafer in the vacuum preparation chamber 2. This completes one cycle of MOVPE growth. After that, the unprocessed wafers, which have already been described, are continuously put into a growth cycle, but when all the processes are completed, in order to avoid contamination of the vacuum preparation chamber 2, a high purity N
_Two semiconductors (not shown) are leaked and a growth-processed semiconductor wafer is taken out, and the next growth wafer is introduced.

[Effects of the Invention] As can be seen from the above description, according to the apparatus of the present invention, it is possible to efficiently obtain a high-quality epitaxial crystal such as AlGaAs, which is prevented from invading oxygen and moisture in the external environment and is very susceptible to these. It can be mass-produced.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. 2 (a), (b) and (c) show a carrier, a wafer holder and a holding operation, respectively. FIG. 3 shows another carrier and a wafer holder. 1 ... Semiconductor wafer transfer mechanism, 2 ... Vacuum preparation chamber, 3 ...
… Vacuum preparation chamber exhaust system, 4 …… Raw material gas supply system, 5 …… Entry / exit door, 6 …… Gate valve, 7 …… Wafer holder, 8 …… Growth chamber, 9 …… Susceptor, 10 …… Cooling water Inlet, 11 …… Cooling water outlet, 12 …… Semiconductor wafer, 13 …… Susceptor rotating mechanism, 14 …… Heater current introduction terminal, 15
...... Growth chamber exhaust system, 16 …… Resistance heater, 17 …… Wafer holder cassette, 18 …… Wafer holder cassette rail.

Claims (1)

[Claims] 1. A rotary susceptor having a source gas introduction port on the top thereof and a plurality of wafer holders each having a semiconductor wafer mounted on a side surface thereof, and a heater and a vacuum exhaust system for heating the semiconductor wafer inside the susceptor. Provided, the raw material gas is heated and decomposed under a predetermined pressure, on the upper side of the growth chamber made of vertical stainless steel for epitaxially growing crystals on a semiconductor wafer, can be communicated to the outside world and can be hermetically closed,
Further, the growth chamber is separated from the growth chamber by a valve, can be independently evacuated, and has a vacuum preparation chamber capable of holding a wafer holder on the susceptor at a number equal to or more than that of the growth chamber. The wafer holder in which the semiconductor wafer is mounted on the susceptor is connected to the carrier at a position below the semiconductor wafer and transferred, or conversely, the wafer holder can be removed from the susceptor and transferred to the cassette in the vacuum preparation chamber. An organometallic vapor phase epitaxy apparatus comprising a transport mechanism.