JPH0336794B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a reduced pressure vapor phase growth apparatus, and particularly to a reduced pressure vapor growth apparatus that performs vapor phase growth by reducing the pressure inside a quartz tube attached to a heating furnace. Regarding.

<Prior Art> In this type of low-pressure vapor phase growth apparatus, a predetermined thin film is grown on the surface of a semiconductor wafer, and the film is also formed on the inner surface of a tube. The film grown on the inner surface of the tube becomes thicker each time a semiconductor wafer is processed, resulting in the following disadvantages. For example, when growing a polysilicon film, the polysilicon film has good adhesion to the tube and the film itself is strong, so if the tube to which the polysilicon film is attached is subjected to temperature changes, the polysilicon film will Due to the difference in thermal expansion coefficient of quartz, a large thermal stress is generated in the tube, which in turn causes a problem of cracking in the tube.
If cracks occur, airtightness cannot be maintained. Therefore, when a film with a thickness of, for example, about 30 to 10 μm grows on the inner surface of the tube, the tube is removed from the heating furnace and cleaned to remove the film formed on the inner surface.

In recent years, in order to solve the above problem, for example, Japanese Patent Application Laid-Open No. 56-28636 and Japanese Utility Model Application No. 58-162634 have proposed a type of reduced pressure vapor phase growth apparatus in which the tube is divided into two parts: an outer tube and an inner tube. is proposed.

<Problems to be Solved by the Invention> However, in carrying out the above-mentioned removal work, all the seals etc. of the device must be removed, which increases the amount of time the device is idle.
A problem arises in that work efficiency in semiconductor wafer processing steps decreases.

The present invention was created in view of the above circumstances, and
It is an object of the present invention to provide a new reduced pressure vapor phase growth apparatus in which a film is prevented from growing on the inner surface of the outer tube by distinguishing and using the tube into an outer tube and an inner tube.

Furthermore, since the structure of the above-mentioned device that is divided into an outer tube and an inner tube is complicated, it is difficult to remove the inner tube. This reduces work efficiency.

Therefore, the present invention aims to provide an extremely convenient low-pressure vapor phase growth apparatus in which the inner tube can be easily removed and attached with a single touch by devising the door section attached to the semiconductor wafer insertion side. There is.

<Means for Solving the Problems> The reduced pressure vapor phase growth apparatus according to the present invention includes an outer tube heated by a thermal contact type heater, an inner tube having a smaller diameter than the outer tube, and an outer tube on the semiconductor wafer insertion side. A packing for sealing between the inner tubes, a first closing part airtightly attached to the outer tube on the semiconductor wafer insertion side, and a second closing part attached to the outer tube on the side of the outer tube opposite to the semiconductor wafer insertion side. This is a reduced pressure vapor phase growth apparatus, and a purge gas inlet for introducing purge gas is provided near the semiconductor wafer insertion side of the outer tube, and a leg is provided on the lower surface of the inner tube so that both tubes can be inserted coaxially. A section is provided, and the first
The closing part includes a door, a ring-shaped main body that is hermetically fitted into the peripheral edge of the semiconductor wafer insertion side of the outer tube via packing, and a ring-shaped holder,
The annular body includes a seal block portion and a protruding cylindrical portion, and the seal block portion is airtightly attached to the outer tube by packing sandwiched between the annular body and the annular holder, and the door has an inner surface thereof and a protruding cylindrical portion. When the packing is sandwiched between the outer peripheries of the annular body, one end is hinged to the protruding cylindrical part of the annular body, and the other end is configured to be airtightly engaged with the protruding cylindrical part by an engagement member. The inner tube is configured to introduce the growth gas through a growth gas introduction hole formed in the cylindrical portion and to discharge surplus gas from the surplus gas discharge hole provided in the second closed portion, and the open end of the inner tube is configured to It is characterized by being provided very close to the surplus gas exhaust hole.

<Operation> Since the outer tube and the inner tube are made airtight on the semiconductor wafer insertion side, the growth gas introduced into the apparatus does not enter the outer tube side. Furthermore, since the growth gas that attempts to enter from the rear side of the outer tube is purged by the purge gas, it cannot enter the outer tube side. Therefore, the outer tube is not constantly exposed to growth gas.

Note that the inner tube can be easily attached and detached by operating the engagement member.

<Example> Hereinafter, an example according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view schematically showing the structure of a reduced pressure vapor phase growth apparatus according to the present invention, and FIG. 2 is a sectional view taken along line AA in FIG.

In the figure, 1 is an outer tube,
This outer tube 1 is heated by a thermal contact type heater.

This outer tube 1 is composed of a quartz tube with both ends open. Reference numeral 2 denotes an inner tube having a smaller diameter than the outer tube 1, and the inner tube 2 is configured to be inserted into and removed from the outer tube 1. The inner tube 2 is composed of a quartz tube with both ends open, and wart-shaped legs 3, 3 are formed on its lower outer surface so that both tubes can be inserted approximately coaxially.

13 is a packing, and the packing 13 is located on the semiconductor wafer insertion side and is interposed between the outer tube 1 and the inner tube 2.

1A is a purge gas inlet provided near the semiconductor wafer insertion side of the outer tube 1, and the purge gas in the purge gas cylinder 16 is introduced into the apparatus through the purge gas inlet 1A via the valve 15.

An inert gas such as nitrogen gas is selected as the purge gas.

A first closing portion 5 that is airtightly attached to the outer tube 1 is provided at the peripheral edge of the outer tube 1 on the semiconductor wafer insertion side.

The first closing portion 5 includes a ring-shaped main body 52 that is airtightly fitted into the peripheral edge of the semiconductor wafer insertion side of the outer tube 1 via a packing 6, a ring-shaped holder 56, a packing 6, a bolt 57, and a hinge 55.
It includes a door 53 including a door 53 and a packing 54.

The annular main body 52 includes a seal block portion 521 and a substantially L-shaped protruding cylindrical portion 52 that protrudes further from the seal block portion 521 in the semiconductor wafer insertion direction.
It is formed from 2. Said seal block part 5
A water cooling jacket 521A is formed inside 21. Further, a bolt insertion hole is provided on the outer peripheral side of the seal block portion 521, and a tapered portion 52B is formed on the lower surface of the seal block portion 521 on the side opposite to the semiconductor wafer insertion side. The packing 6 is sandwiched between the tapered part 52B and the annular holder 56, and the annular holder 56 and the seal block part 521 are connected and fixed with bolts 57, and are configured to maintain airtightness with the outer tube 1.

One end of the door 53 is hinged to the protruding cylindrical portion 522 of the annular body 52, and the other end of the door 53 is hinged to an engaging member 55 such as a fastener.
This engaging member 55 is locked to the protruding cylindrical portion 522. Note that it is preferable to have a plurality of engaging members 55 from the viewpoint of airtightness. The engaging member 55 has a U-shape, for example, and has a locking pawl 55A formed at its tip, and the locking pawl 55A locks into a locking recess 522A formed in the protruding cylindrical portion 522. By doing so, the door 53 is closed.

In this case, in order to maintain airtightness between the door 53 and the seal block portion 521, a packing 54 is airtightly fitted between the tip side of the protruding cylindrical portion 522 and the inner surface of the door 53. Therefore, the packing 6 and the packing 54 close the outer tube 1 and the first closing portion 5.
can maintain airtightness.

A gas introduction hole 522A is formed in the protruding cylindrical portion 522, and a growth gas such as monosilane gas is introduced into the apparatus from the gas cylinder 7 via the valve 8.

A second closing portion 9 is attached to the side of the outer tube 1 opposite to the semiconductor wafer insertion side through a packing 10. Surplus gas discharge hole 9 is provided in the second blocking part 9.
1 is provided. The exhaust pump 11 exhausts surplus gas within the device to the outside through the surplus gas exhaust hole 91. Note that 12 indicates semiconductor wafers arranged in a quartz boat (not shown) inside the inner tube 2.

Next, the handling of the reduced pressure vapor phase growth apparatus having the above-described configuration will be explained.

First, the door 53 is opened and the semiconductor wafer 1 is opened.
The quartz board on which 2 is placed is the inner tube 2.
inserted within. Thereafter, the door 53 is closed by locking the fastener 55 to the protruding cylindrical portion 522.

Evacuate and depressurize the inside of the device. After the pressure is reduced, the outer tube 1 is heated to a predetermined temperature by the heater.

Thereafter, the growth gas is supplied from the gas cylinder into the apparatus, and the purge gas is introduced from the purge gas inlet 1A. Even if the growth gas tries to enter from the rear side of the outer tube 1 (the side opposite to the semiconductor wafer insertion side), it is purged by the purge gas, so that the growth gas is ultimately prevented from entering the outer tube 1 side.

The exhaust pump 11 is operated and the valve 8 is controlled to open and close in accordance with the concentration of the growth gas in the apparatus, and a thin film is formed on the semiconductor wafer 12. A film is also formed on the inner surface of the inner tube 2, but no film is formed on the inner surface of the outer tube 1.

By the way, in the above-described apparatus, it is extremely important to control the thickness of the film grown on the inner surface of the inner tube 2 in order to prevent the inner tube 2 from being damaged.

However, it is difficult to directly measure the thickness of the film attached to the inner tube 2. Therefore, as shown in FIG. 4, a semiconductor wafer 21 cut into strips is placed along the axial direction inside a tube 20 such as the above-mentioned inner tube 2, for example. In order to accurately measure the film thickness, the semiconductor wafer 21
is preferably in close contact with the inner surface of the tube. This is also the reason why the semiconductor wafer 21 cut into strips is used. In this way, the semiconductor wafer 21 can be taken out and the film thickness on the inner surface of the tube can be accurately measured using an interference microscope or the like.

<Effects of the Invention> The reduced pressure vapor phase growth apparatus according to the present invention includes an outer tube heated by a thermal contact type heater, an inner tube having a smaller diameter than the outer tube, and a tube between the outer tube and the inner tube on the semiconductor wafer insertion side. Reduced pressure vapor phase growth comprising a packing for sealing, a first closing part airtightly attached to the outer tube on the semiconductor wafer insertion side, and a second closing part attached to the outer tube on the side of the outer tube opposite to the semiconductor wafer insertion side. In the apparatus, a purge gas inlet for introducing purge gas is provided near the semiconductor wafer insertion side of the outer tube, and legs are provided on the lower surface of the inner tube so that both tubes can be inserted coaxially. and the first
The closing part includes a door, a ring-shaped main body that is hermetically fitted into the peripheral edge of the semiconductor wafer insertion side of the outer tube via packing, and a ring-shaped holder,
The annular body includes a seal block portion and a protruding cylindrical portion, and the seal block portion is airtightly attached to the outer tube by packing sandwiched between the annular body and the annular holder, and the door has an inner surface thereof and a protruding cylindrical portion. When the packing is sandwiched between the outer peripheries of the annular body, one end is hinged to the protruding cylindrical part of the annular body, and the other end is configured to be airtightly engaged with the protruding cylindrical part by an engagement member. The inner tube is configured to introduce the growth gas through a growth gas introduction hole formed in the cylindrical portion, and to discharge surplus gas from the surplus gas discharge hole provided in the second closing portion, and the open end of the inner tube is configured to Since it is characterized by being provided very close to the surplus gas discharge hole, the growth gas grows on the inner surface of the inner tube, but almost no film grows on the inner surface of the outer tube.

Therefore, according to the present invention, when taking out the inner tube for cleaning, it is not necessary to remove the seal part of the outer tube at all, so the down time of the device can be shortened and the overall work efficiency can be improved. .

Furthermore, since this invention maintains airtightness through the outer tube, even if a crack occurs in the inner tube, the airtightness of the entire device can be maintained like in conventional devices, so there is no need to replace the tube. No, it's very reasonable.

Further, with the above configuration, the inner tube can be attached or detached simply by operating the engagement member, so that work efficiency can also be improved.

Furthermore, in the present invention, since the open end of the inner tube is provided very close to the surplus gas discharge hole,
Growth gas does not accumulate near the excess gas exhaust hole. If this becomes a reservoir of growth gas,
As a result of the spent growth gas staying here being mixed with the growth gas flowing from upstream, the components of the growth gas are substantially changed, making it impossible to grow a good film. This does not happen with the present invention.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing the structure of a reduced pressure vapor phase growth apparatus according to the present invention, and FIG.
-A sectional view and FIG. 3 are explanatory diagrams of a method for measuring the thickness of a film grown on the inner surface of a tube. DESCRIPTION OF SYMBOLS 1... Outer tube, 2... Inner tube, 5... First closed part, 9... Second closed part, 12... Semiconductor wafer.

Claims (1)

[Claims] 1 An outer tube heated by a thermal contact type heater, an inner tube with a smaller diameter than the outer tube, a packing that seals between the outer tube and the inner tube on the semiconductor wafer insertion side, and an airtight seal with the outer tube on the semiconductor wafer insertion side. a first closure attached;
A reduced pressure vapor phase growth apparatus is provided with a second closing part attached to the outer tube on the side opposite to the semiconductor wafer insertion side of the outer tube, and a purge gas inlet for introducing purge gas is provided near the semiconductor wafer insertion side of the outer tube. A leg portion is provided on the lower surface of the inner tube so that both tubes can be inserted coaxially, and the first closing portion is connected to the semiconductor wafer insertion side of the outer tube via the door and packing. The ring-shaped main body includes a ring-shaped main body that is airtightly fitted into the peripheral portion, and a ring-shaped holder, and the ring-shaped main body includes a seal block portion and a protruding cylindrical portion. The door is airtightly attached to the outer tube, and one end of the door is hinged to the protruding cylindrical part of the annular body, and the other end is engaged, with the packing sandwiched between the inner surface of the door and the outer periphery of the protruding cylindrical part. The member is configured to be airtightly locked to the protruding cylindrical part, and the growth gas is introduced through the growth gas introduction hole formed in the protruding cylindrical part.
The inner tube is configured to discharge surplus gas from a surplus gas discharge hole provided in the second closed part, and the open end of the inner tube is provided in close proximity to the surplus gas discharge hole. Reduced pressure vapor phase growth equipment.