JPS60112691A - Substrate supporting device for molecular beam epitaxial growth device - Google Patents

Abstract

PURPOSE:To obtain a titled device which is easily detachable and by which uneven distribution of temps. of a substrate can be avoided by supporting the titled substrate at the circumferential part, and providing a member for making the heating uniform between the rear surface of the substrate and a heater for heating the substrate while leaving a vacuum space between the rear surface and the member. CONSTITUTION:A discoid member 3 for making the heating uniform is provided on a substrate support 2 while leavig a clearance enough to absorb the heat fluctuation, and a C ring 1'' is inserted into a C ring groove 10'' of the substrate support 2 and a C ring 1'' into a C ring groove 10'. A ring 1 for preventing the falling of the substrate is inserted into a C ring groove 10 at the inner wall of an opening part of the substrate support 2, and a vacuum space 30 is provided between the substrate 4 and the member 3 for making the heating uniform. Since the substrate is retained by its own weight, the stress is not formed even when the substrate is heated at high temps. An uniform temp. distribution can be easily obtained in this way. As the device is simple, the handling of the substrate in the semiconductor manufacturing process is simplified, and the device can be automated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a holding device for a compound semiconductor substrate in a molecular beam epitaxy growth apparatus.

Conventionally, this method of holding the substrate was carried out exclusively by placing a low-melting point metal such as indium or gallium between the substrate and the substrate holder and applying heat.
The low melting point metal adhesion method, in which the two are bonded together, or the metal piece fixation method, in which the board is placed on a board holder and small pieces of metal are pressed and fixed at several points on the edges, has been adopted. However,
These methods have the following drawbacks. In other words, with the low melting point metal bonding method, it is difficult to uniformly spread the low melting point metal on the back surface of a large substrate, completely eliminate air bubbles, and achieve even bonding. Since the source of the adhesive is easily damaged, and the thermal conductivity of the adhesive is high, current non-uniform adhesive bonding such as air bubbles causes uneven thermal conductivity, making it difficult to ensure a uniform in-plane substrate temperature distribution. I'm jealous. Furthermore, since the time required for adhesion is long, there is a drawback that the surface of the substrate is heavily contaminated during that time.

In order to use the substrate after epitaxial growth is completed in 1y in a semiconductor device manufacturing process.

Although it is necessary to completely remove the low melting point metal on the substrate surface,
In this removal process, the low melting point metal is removed with acid, which has the disadvantage that the surface of the grown film is contaminated with this metal.

Sara K again. When the substrate temperature exceeds, for example, 750°C during epitaxial film growth, indium evaporates and this metal is lost as an impurity in the substrate.On the other hand, with the metal piece fixing method, several places on the edge of the substrate are made to have high thermal conductivity. Since the substrate is fixed by pressure contact with a small piece of metal, significant non-uniformity in substrate temperature occurs near the pressure and fixation part. In addition, since mechanical pressure bonding is used, stress is applied to the substrate during thermal expansion and contraction, causing defects in the grown film on the substrate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a substrate holding device that overcomes these conventional drawbacks. An object of the present invention is to provide a simple and inexpensive substrate holding device that is much easier to attach and detach than conventional substrate holding devices.

In addition, the present invention allows easy degassing and does not cause stress during high-temperature processing.

It is an object of the present invention to provide a novel substrate holding device that does not cause temperature t#' non-uniformity on the substrate.

The present invention will be explained below by way of examples using the figures.

Figure 1 is an embodiment of the present invention and is 1111'! 1' is a CIJ ring (C-type retaining ring) for preventing the board from falling,
It is made of wire made from tungsten or molybdenum, which are high-melting point metals.

2 is a substrate holding stand also made of molybdenum, a high melting point metal, 3
is a disc-shaped heating uniformity member made of pyrolytic graphite, which has high cavity emissivity and high thermal conductivity. 5 is a heater for heating the substrate, and 6 is the direction in which the molecular beam comes.

In the present invention, after installing the disc-shaped heating uniformity member 3 on the 1l-j substrate holding table 2 with a gap equal to or larger than the thermal change, the C ring 1 is placed in the Cl blow groove 10' of the substrate holding table 2. ' and lock it, and then similarly insert C-ring 1' into C-ring groove 10'.

The disk-top substrate 4 is also inserted with a gap, and a substrate fall prevention ring is fitted into the CIJ groove 10 on the inner wall of the opening of the substrate holder 2.

Therefore, a vacuum space 30 is provided between the disc-shaped substrate 4 and the heating uniformity member 30.

At this time, the substrate 4 is also given clearance in the direction perpendicular to its surface. That is, the substrate holding (L-'r) of the present invention is
, Even if the direction IC is along the board surface, the direction perpendicular to the board surface l
(However, all of this is done in a no-pressure state with a slight gap between them. Therefore, the board is able to lift itself by its own weight.)
It occupies a large area and does not cause stress even when heated to high temperatures. The substrate 4 is heated by the infrared rays of the heating element 3 passing through the vacuum space 30, and the heating uniformity member 3 is made of pyrolytic graphite and is thick due to its high emissivity and high thermal conductivity. By allowing the rod to stand up, the entire surface of the drink will be free and it will have a uniform level of intoxication. Thus, the shape of the incandescent part of the substrate heating heater 5 is the same as that of the heating uniform member 3.
However, the substrate 4 is heated only by the infrared rays radiated from the surface of the member 3. Therefore, the substrate 4 has a uniform temperature JW4+ over its entire surface.
Cloth is secured. To ensure uniformity of temperature distribution,
Ideally, the surface of the heating equalizing member 3 that approaches the substrate 4 is smooth and has no irregularities.

Note that the heating uniformity member of the present invention may be made of a limited material such as the pyrolytic graphite of the embodiment.

Thank you very much. The shape and number of the holding members are not limited to those in the embodiments, and may be modified while respecting the spirit of the invention.

The substrate holding device 7t of the present invention is as described above.

Even with a thermal cycle of product temperature (7), stress does not occur on the board, and a board temperature with an even -VC distribution can be easily ensured.

Since the apparatus is simple, it is easy to increase the number of substrates in the semiconductor device fabrication process, and there is also the advantage that automation is possible, so it can be said to be a valuable invention in industry.

4. FIG. 1 Brief Description FIG. 1 is a side sectional view of a substrate holding device according to an embodiment of the present invention. FIG. 2 is a plan view thereof.

1.1', ': C ring, IQ, ](1', 10'
: C-ring groove 2: Substrate holding stand, 3: Heating uniformity member.

4: Board plate, 5: Heater for heating the substrate.

Claims (2)

[Claims] (1) Support the compound semiconductor substrate for molecular beam epitaxial growth around the substrate, and have high thermal conductivity and/or high emissivity between the back surface of the substrate and the substrate heating heater that heats it. For use in a molecular beam epitaxial growth apparatus, characterized in that a heat-resistant heating equalization member is provided and a vacuum space is provided between the back surface of the substrate and the heating equalization member to uniformize the heating of the substrate. substrate holding device. (2) The substrate holding device for a molecular beam epitaxial growth apparatus according to item 1, wherein the heating uniformity member is made of pyrolytic graphite.