JPS5918195A - Thin film growth device in extremely high vacuum - Google Patents

Abstract

PURPOSE:In transporting a base consisting of plural plates set in a cassete from a base introduction chamber to a preparative exhaust chamber, to raise the treatment speed of the base and to simplify the treatment operation, by carrying out simultaneously the transportation of the cassete and the opening and closing of a pair of opposing partition wall integrated with the cassete by the partition wall. CONSTITUTION:The base 4 consisting of plural plates is set in the cassette 5, equipped in the introduction chamber 1, and the introduction chamber 1 is evacuated. The shaft 7 is driven by the air cylinder 6, and the cassete 5 is transferred to the preparative exhaust chamber 2 which is previously evacuated. In the operation, a pair of opposing partition walls 8 and 9 are also transferred in an integrateded way with the cassete 5. Consequently, the opening and closing of the partition walls 8 and 9 are carried out simultaneously with the transportation of the cassete 5, so the treatment of the base can be done simply at high speed. After the cassete 5 is transferred to the preparative exhaust chamber 2, the base 4 in the cassete is one by one sent to the heating part 11 of the evacuated growth chamber 3 by the shaft 10, and desired film growth is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultra-high vacuum thin film growth apparatus that has a high processing speed, is easy to operate, and can uniformly heat a substrate to a high temperature range.

Conventional devices of this type often load substrates one by one into the substrate introduction chamber, and the cycle of evacuation, growth, and extraction must be repeated for each substrate, resulting in an extremely long processing time for each seven substrates. was there.

In addition, even in the method of loading several substrates into the substrate introduction chamber at once using a cassette, in conventional equipment the cassette and isolation wall are not integrated, and when the cassette is transferred to the pre-evacuation chamber, the cassette is isolated. Since the opening/closing of the wall and the transport of the cassette were configured to be operated separately, there were also disadvantages in that the processing time was long and the operations were complicated.

Regarding substrate heating, there is a method of heating the substrate to a high temperature range of about 700° C. or higher, for example, using tantalum wire or striped graphite as a heating base. However, when a substrate is directly heated with these heaters, there is a drawback that the substrate is heated locally along the shape of the heater when the heat conduction A is relatively small, such as silicon. Step 9: In order to uniformly heat the board, it is necessary to insert a metal plate such as molybdenum with high thermal conductivity between the heater and the board, and to heat the board uniformly from the back side of the board. This has the drawback that the heat transfer efficiency decreases and it is difficult to heat the substrate above about 700°C.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ultra-high vacuum thin film growth apparatus that eliminates the above-mentioned drawbacks, increases the processing speed per seven substrates, and simplifies the processing operations.

In order to achieve such an object, the present invention provides a mechanism for transporting the cassette using a pair of opposing bulkheads that are integrated with the cassette when a plurality of substrates are introduced from the substrate introduction chamber into the pre-evacuation chamber while the cassette is still loaded. It is characterized by opening and closing the isolation wall and the isolation wall at the same time.

Furthermore, when heating the substrate in the growth chamber, the strip-shaped graphite heaters are stacked on top of each other so as to compensate for the gaps between the stripes. It is characterized by the provision of an insulating plate, thereby realizing uniform heating up to a high temperature range.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, and is a schematic plan view of the entire device. The exhaust system has been completely omitted here. In the figure, / is a substrate introduction chamber, C is a preliminary exhaust chamber, and 3 is a growth chamber. To grow thin films on multiple substrates, such as silicon wafers, use a cassette! After the required number of cassettes are loaded into the substrate introduction chamber l and the inside of the substrate introduction chamber l is evacuated to about /θ-' Torr using a turbo molecular pump, the cassette j is transferred to the preliminary evacuation chamber by a shaft 7 driven by an air cylinder B. At this time, a pair of isolation walls facing each other! and wa also move together with cassette j. Because of this structure, when installing the board, the board introduction chamber / and 10-? are under atmospheric pressure. The preliminary evacuation chamber 2, which is evacuated to about TOrr with a cryopump, is separated by an isolation wall 9, and the cassette! After being transferred, the cassettes are separated by the separating wall r, and the separating walls t and 9 can be opened and closed at the same time as the cassette j is transferred, allowing fast and high-speed processing.

For example, it takes 5 minutes from when /θ bags of Ginch silicon ueno\ are attached to when they are transferred to the preliminary exhaust chamber.

After transferring the cassette j to the preliminary exhaust chamber 2, use a shaft /θ driven by a magnetic coupling, for example, to remove the cassette! (multiple sea urchins) z lI /θ-9T
The substrate is transferred to the substrate heating section/l of the growth chamber 3, which is evacuated to about 100 yen by cryopump.

After the desired film growth, this Ueno 1 is placed in the cassette in the pre-evacuation chamber using the shaft /θ again! and transport other wafers to the growth chamber 3 as necessary. After processing a predetermined number of wafers, the above procedure is reversed to take out the wafers 41 from the substrate groove. In addition, when transferring the sea urchin from the cassette j to the shaft 10 in the preliminary exhaust chamber,
For example, such transfer is performed by moving the cassette up and down using a motor drive shaft provided at the bottom of the preliminary exhaust chamber λ.

Figures 1 and 2 are cross-sectional views showing an example of the substrate heating section/l in the growth chamber 3, and Figure 1 (J3) is a plan view of the second layer graphite heater/2. C) Same as Ha.

FIG. 3 is a plan view of the seventh layer of graphite heater/3.

In FIG. λ, /J and /J are electrodes for energizing the second layer and /NN upper heater, respectively, and are made of tantalum, for example. / and /7 are quartz plates into which graphite heaters /2 and /3 are fitted in the second layer and /Ju, respectively, and between each layer of graphite heaters /2 and /3 and between heaters /2 and /3 and silicon. This is to provide electrical insulation between the sea urchin bald and the sea urchin bald without reducing heat transfer efficiency. The quartz plate /7 also has the role of preventing contamination from heaters /2 and /3 to the silicon sea urchin bald. /l is a reflective plate, which is used to increase the efficiency of heat transfer to the sea urchin bald.

Heaters /λ and /3 are arranged so as to compensate for each other's gaps. According to such a structure, it is possible to heat the sea urchin bald to a high temperature of about 130° C. without causing temperature non-uniformity inside the sea urchin bald. In a structure like this 7, the uniformity is, for example, 1 for a die-inch silicon wafer.
It is within θ°C of OOO°C.

The uniformity of temperature and growth film thickness can be further improved by rotating the support frame 19 of the sea urchin bald.

Note that when providing a gap between heaters /2 and /3, the quartz plate 16 may not be provided.

Further, in a low temperature range where contamination of the substrate from the heaters /2 and /13 can be ignored, the quartz plate /7 may not be used. Furthermore, alumina plates can be used instead of quartz plates/6 and 17.

As explained above, according to the present invention, when transferring a cassette containing a large number of substrates between the substrate introduction chamber and the preliminary exhaust chamber, it is possible to simultaneously open and close the isolation wall and transfer the cassette. This has the advantage of achieving high processing speed, simple operation, and easy automation.

In addition, in the present invention, when heating the substrate in the growth chamber, two graphite heaters are used to compensate for the gaps between the stripes.
Since the structure is such that gaps or insulating plates such as quartz or alumina are provided between the layers and between the substrate and the heater, there is an advantage that the substrate can be uniformly heated to a high temperature range.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the ultra-high vacuum thin film growth apparatus according to the present invention, especially to explain the transfer of a substrate;
Figure (4) is a block diagram showing an embodiment of the ultra-high vacuum thin film growth apparatus of the present invention, with particular explanation of the substrate heating section, and Figures λ (CB) and (C) respectively show the graphite heater thereof. FIG. /... Board introduction chamber, -... Preliminary exhaust chamber, 3.
...Growth room, Hiroshi...Substrate (silicon wafer)! ...Cassette, B...Air cylinder, 7...Shaft, ff, 9...Isolation wall, lθ...Shaft, //...Substrate heating section, /2
..., second layer graphite heater, /3... seventh layer graphite heater, #, /j... current-carrying electrode, /6. /7...Quartz plate, 1g...Reflector,
19...Support frame.

Claims (1)

[Claims] l) In a vacuum thin film growth apparatus having a substrate introduction chamber, a pre-evacuation chamber, and a growth chamber, when introducing a substrate from the atmosphere into a vacuum, a plurality of substrates are mounted in a cassette, The cassette is placed in the substrate introduction chamber separated from the pre-evacuation chamber by a first isolation wall, and after the substrate introduction chamber is evacuated, the cassette is transferred to the pre-evacuation chamber that has been previously evacuated. When the first isolation wall and the second isolation wall facing the first isolation wall are moved together with the cassette, when the cassette is stored in the preliminary exhaust chamber, the first isolation wall and the second isolation wall facing the first isolation wall are moved together with the cassette. An ultra-high vacuum thin film growth apparatus characterized in that the substrate introduction chamber and the preliminary evacuation chamber are isolated by the second isolation wall that has been moved. , 2) Substrate introduction chamber 1. In a vacuum thin film growth apparatus having a preliminary evacuation chamber and a growth chamber, when introducing a substrate from the atmosphere into a vacuum, a plurality of substrates are mounted in a cassette,
The cassette is placed in the substrate introduction chamber separated from the pre-evacuation chamber by a seventh isolation wall, and after the substrate introduction chamber is evacuated, the cassette is placed in the pre-evacuation chamber that has been evacuated in advance. When transferring, the first isolation wall and the first isolation wall opposite to the first 11 ft wall are moved together with the cassette, and when the cassette is stored in the pre-evacuation chamber, the cassette is removed. The substrate introduction chamber and the preliminary evacuation chamber are separated by the first partition wall that moves together with the substrate. Two graphite heaters are arranged so that the gaps between their stripes compensate for each other.
An ultra-high vacuum thin film growth apparatus characterized in that graphite heaters are arranged in layers to insulate between the two layers of graphite heaters and between the substrate and the graphite heater.