JPH1053498A - Reaction vessel for semiconductor wafer and heat-treating apparatus using the vessel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reaction vessel for a semiconductor wafer capable of suppressing the increase in the size of the apparatus and the generation of particles and keeping high heat-insulation performance without using a separate heatinsulation cylinder and to provide a heat-treating apparatus by using the reaction vessel. SOLUTION: This reaction vessel 50 for the heat treatment of a semiconductor wafer 10 in a state held in the vessel shown by the drawing has a wafer- holding reaction vessel main body 52 made of a transparent quartz glass and a flange part 60 connected to the main body 52 and having a sandwich structure 63 composed of an opaque quartz glass 61 and a foamed quartz glass 62 containing a number of small spaces in and quartz thin films extending in vertical and lateral directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer reaction vessel used for semiconductor wafer diffusion processing, oxidation processing, low-pressure CVD, etc., and a heat treatment apparatus using the vessel. The present invention relates to a single-wafer-type semiconductor wafer heat treatment apparatus housed in a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, in the case of heat treatment of a semiconductor wafer, a batch method has been adopted in which a plurality of wafers are stacked and mounted on a wafer boat and batch heat treatment is performed in a reaction vessel. In this method, it is difficult to uniformly process the input wafer by causing turbulence in the airflow generated near the contact portion between the wafer and the boat and turbulence in the airflow by stacking the wafers in multiple stages. Further, as the diameter of the wafer becomes larger, it is difficult to manufacture a boat and a supporting portion corresponding to the weight burden in the batch processing method, and the reaction vessel becomes larger due to the larger diameter, the heating temperature distribution and the like. This has led to uniformization of gas distribution and unnecessary increase in the number of heating sources, and there have been various problems that are difficult to cope with with a conventional batch method in order to cope with an increase in the diameter of a wafer. In addition, the next generation of 64
Sub-micron unit accuracy is required in semiconductor manufacturing processes with high integration densities such as M and 1G. In a batch system that processes a plurality of wafers at a time, the stacking position of wafers and the inflow side and outflow side of the gas flow are respectively Variations in processing conditions occur, affect each other between stacked wafers, and generate particles and the like from contact portions of the boat, making high-quality processing difficult.

In order to solve the above problem, attention has been paid to a single-wafer heat treatment apparatus for performing heat treatment for each wafer, and various proposals have been made.
No. 54) discloses the following single-wafer heat treatment apparatus. In the heat treatment apparatus, a wafer placed horizontally on a susceptor by a heating source provided below the susceptor is heated in a low-pressure reaction gas atmosphere to form a film on the wafer. When the wafer is placed horizontally, the following problems are incorporated. 1) Since the wafer is placed horizontally, there is a problem that the wafer is bent by its own weight. 2) The reaction vessel becomes large. Therefore, a power source such as a heating source also becomes large.

Therefore, the present inventors have been involved in the development of a single-wafer-type wafer heat treatment apparatus in order to cope with an increase in the diameter of the wafer and a high integration density of the next generation 64M, 1G, etc. Japanese Patent Application No. Hei 8-224823 proposes a proposal for a heat treatment apparatus for a semiconductor wafer having a single-wafer reaction container having a shape capable of securing a necessary minimum size and a wafer upright support device with respect to the size of a wafer to be formed. ing.
(Unknown)

In the above proposal, the wafer is stored in an upright position, and the heat distribution on the wafer surface is made uniform and the distribution of the reactant gas flow is made uniform. It has a flat dome shape, and is designed to keep the size of the reaction vessel to a minimum. That is, as shown in FIG. 5, a flat dome-shaped reaction vessel 50, a support device 40 for supporting the wafer 10 upright in the vessel, and a pair of flat plate-shaped heat generators disposed facing the flat side of the reaction vessel 50. The reaction vessel 50 is formed by welding and joining a flange 51 made of non-transparent quartz glass to a reaction vessel body 52 integrally formed of transparent quartz glass, and a reaction gas flows into the upper part of the vessel 52 as necessary. Hole 5
3 and is discharged from the lower discharge hole 58. The upright support device 40 is made of quartz glass or silicon carbide, and supports the wafer 4 upright.
1 and a base body 42 hermetically sealed to the lower surface of the flange via an O-ring 54.

According to the above proposal, the reaction vessel 50 has vacuum strength even if it is made thin. Light weight can be achieved due to the thinness. Good gas flow along the inner curved surface. However, the processing space in the reaction vessel 50 is 600 to
Since heat treatment is performed at a high temperature of about 1000 ° C., the O-ring 54 and other flanges that function as seals are located immediately below the reaction vessel main body 52 serving as a heat treatment space. Therefore, in the technique, the flange is formed of non-transparent quartz glass, and
Although the high temperature is prevented from propagating to the ring 54 and other sealing parts, it is not always sufficient. For this reason, in a vertical furnace core tube using a cylindrical reaction vessel, a heat insulating tube made of quartz glass is arranged between the heating section in the furnace core tube and the opening end side of the furnace tube to equalize the space temperature for the wafer heat treatment. At the same time, the heating element 57 surrounding the furnace core tube is positioned above the heat insulating tube, and the heat insulating tube functions as a heat shut-off means. Prevents high temperatures from propagating.

In general, such a heat insulating cylinder is constituted by enclosing a long fiber-shaped quartz glass wool in a sealed quartz glass cylinder, as disclosed in Japanese Patent Application No. 62-20349.
9, a quartz glass foam in which the heat insulating cylinder is provided with a large number of minute spaces inside and a quartz thin film is stretched vertically and horizontally;
In other words, the foam is not formed of a flexible member such as glass wool, but has a large number of minute spaces inside, such as a foam glass body, and is itself formed of a hard thin-film quartz glass. A proposal made of a quartz glass body stretched vertically and horizontally in a mesh shape has been proposed.

However, the use of the independent heat insulating cylinder as described above not only increases the number of parts, but also tends to generate particles due to rubbing with the wafer board installed on the upper surface of the heat insulating cylinder. Basically, in the single-wafer reaction vessel 50, as shown in FIG. 5, the space between the vessel body 52 and the flange is extremely close to each other, so that there is no room for interposing a heat insulating cylinder.

[0009]

SUMMARY OF THE INVENTION In view of the drawbacks of the prior art, the present invention does not use an independent heat insulating cylinder, suppresses the size of the apparatus, suppresses the generation of particles, and maintains a high thermal insulation. It is an object of the present invention to provide a reaction vessel for a semiconductor wafer to be obtained and a heat treatment apparatus using the vessel.

[0010]

According to the first aspect of the present invention,
In a reaction vessel 50 for wafer heat treatment in which heat treatment is carried out in a state in which a semiconductor wafer is contained, a reaction vessel main body 52 for containing a wafer is formed of a transparent quartz glass body, and a flange portion 60 connected to the main body 52 is made of non-transparent quartz. It is characterized in that it is formed by a sandwich structure 63 of a glass body 61 and a quartz glass foam body 62 having a large number of minute spaces inside and a quartz thin film stretched vertically and horizontally. Here, the non-transparent glass body includes both a translucent and an opaque glass body, but does not include a glass body whose frosted glass-like surface is only opaque. The present invention is particularly applicable to the single-wafer reaction vessel 50.
However, the present invention is not limited to this, and is also applicable between vertical furnace cores having a flange at the lower end of the vessel opening.

The invention according to claim 2 is characterized in that the reaction vessel main body 52 is specified and is formed of a flat curved body so that the wafer can be stored upright. The non-transparent quartz glass is composed of quartz glass containing bubbles having an apparent density of 0.9 g / cm ³ or more, and the bubbles have a diameter of 10 to 250 mm.
20,000 / cm ³ or more, preferably 4 μm
It refers to the presence of 0000 to 70,000 particles / cm ³ . The quartz glass foam 62 has an apparent density of 0.1 to
It is preferable to use 0.8 g / cm ³ of expanded quartz glass.

According to a fourth aspect of the present invention, there is provided a heat treatment apparatus comprising a reaction vessel 50 accommodating a semiconductor wafer and a supporting means 40 for supporting a wafer in the vessel. A sandwich structure 63 of a body 61 and a quartz glass foam body 62 having a large number of minute spaces inside and having a quartz thin film stretched vertically and horizontally.
Is provided.

In this case as well, it is effective to apply the invention to a single-wafer heat treatment apparatus. As described in claim 5, the supporting means 40 supports the semiconductor wafer substantially upright in the container. And the reaction vessel 50
However, it is preferable to form the wafer into a flat curved body so that the wafer can be stored upright. Preferably, the surface of the foam 62 is covered with a transparent glass layer, and the minute space of the foam 62 is preferably in a reduced pressure or vacuum state.

In order to solve the shortage of the strength of the sandwich structure 63 in the vertical direction, a bar-shaped keel may be provided if necessary.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described together with the illustrated example. However, unless otherwise specified, the dimensions, shapes, relative positions, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent. FIG.
Is a schematic configuration diagram showing an example of a heat treatment apparatus using the sandwich structure 63 in the flange portion 60 of the reaction vessel 50,
FIG. 2 and FIG. 3 are schematic configuration diagrams of a heat treatment apparatus in which the sandwich structure 63 is incorporated in the wafer support apparatus 40.

The heat treatment apparatus shown in FIG. 1 has a flat dome-shaped reaction vessel 50, a support apparatus 40 for supporting a wafer upright in the vessel, and a pair of flat plate-shaped pieces disposed facing the flat side of the reaction vessel 50. A heating element 57,
As in FIG. 5, the reaction vessel 50 has a flat dome shape that is flat with respect to the heat-treated surface of the wafer, the size of the reaction vessel 50 is kept to a minimum, and the reaction vessel 5
Numeral 0 is a foam glass plate made of a quartz glass foam 62 in which a non-transparent quartz glass plate is provided in a reaction vessel main body 52 made of transparent quartz glass, and a large number of minute spaces are provided, and a quartz thin film is stretched vertically and horizontally. Are sequentially laminated and welded to the flange portion 60 having the sandwich structure 63. It is to be noted that the reactant gas flows in from the upper inlet 53 of the container 52 and is discharged from the lower outlet 58 as required. The upright support device 40 is made of quartz glass or silicon carbide, and includes a support portion 41 that supports the wafer upright and a base body 42 that seals the lower surface of the flange through an O-ring 54.

The procedure for manufacturing the sandwich structure 63 will now be described with reference to FIG. 4. First, the non-transparent glass plate is internally formed with a diameter of 10 to 250 μm and a diameter of 2 to 1 cm ^3.
A foam containing 0000 or more, preferably 40,000 to 70,000 bubbles / cm ³ is prepared. This production method uses a crystalline quartz powder containing no crystallization water as a raw material powder as is well known, and the particle size distribution is 300 to
The heating and melting conditions are controlled, for example, to 1 in a range of 100 μm.
It is easily formed by melting while controlling the temperature to 600 ° C. or higher. Next, as shown in FIG.
The non-transparent quartz glass plate 61B is
Substantially the same shape as that of the flange 6
In addition, a leg 610 made of a rod-shaped non-transparent quartz glass body is welded to a lower surface of the ring 610 in a shape of an oval ring. The length of the leg 610 is set substantially equal to the thickness of the foam 62 described later.

Next, a ring-shaped elliptical quartz glass container 65 made of the non-transparent quartz glass body 61 having the same shape as the flange portion 60 but having a large height is formed as a container 65 for forming a flange. After that, the quartz fine powder 62 ′ and the non-transparent quartz glass plate 6 with legs are placed in the container 65.
1B Further, a quartz fine powder 62 'is sequentially put thereon, and after forming a laminate in which the quartz fine powder 62' and the flange portion 60 are alternately laminated, heating is performed at a temperature of about 1300 to 1600 ° C in a vacuum furnace. As a result, as shown in FIG. 4B, a quartz glass foam 62 having a large number of minute spaces 62a therein and having a quartz thin film 62b stretched vertically and horizontally (the cross-sectional structure is shown in FIGS. 6A and 6B). ) And (C)) and the non-transparent quartz glass plate 61 are alternately laminated to form a sandwich structure 63. 61 is 61A, 61B, 61C
Is a generic term for At this time, foamed glass-like foam 62 having more vacuum microspaces can be formed by heating in a state in which water is mixed together with carbon powder in the quartz fine powder to form a mud.

The surface of the foam 62 is welded integrally with the quartz container 65 and the quartz glass plate 61 by the heating, and the volume is reduced by the heating. And a foam 62 having a thickness approximately equal to the leg length of the flange portion 60 is set by heating. Then, the upper open portion of the container 65 is cut, and an elliptical ring-shaped lid 61A made of non-transparent quartz glass is welded to the upper surface to form a sandwich structure 63 shown in FIG. 4B.

The reaction vessel 50 is formed by welding the sandwich structure 63 thus formed to the open end of the reaction vessel main body 52. It should be noted that, after adopting such a configuration, after forming the foam 62 in a carbon crucible, the foam 62 was cut into a plate to form an elliptical ring-shaped plate. Alternatively, after alternately laminating with the non-transparent quartz glass plate, the layers may be integrally welded by heating in a vacuum furnace.

According to this embodiment, the non-transparent quartz glass plate 61 itself has a great strength compared to the foam 62, while the foam 62 has a great strength compared to the non-transparent quartz glass plate 61. By having a large heat insulating property and thus having a sandwich structure, the heat insulating property can be achieved with a sufficient strength even if the diameter of the reaction vessel main body 52 is increased by having a pressure resistance. Therefore, in the above embodiment, since the flange body 60 of the sandwich structure 63 is formed immediately below the reaction vessel main body 52 for performing the heat treatment, the heat treatment temperature in the vessel main body 52 is heated to about 600 to 1100 ° C. However, it is possible to effectively prevent high temperature from propagating to the O-ring 54 and other seal portions on the lower surface side of the flange surface.

FIGS. 2 and 3 show another embodiment in which the sandwich structure 63 is disposed on a semiconductor wafer support device 40. FIG. The support device 40 of the present embodiment includes a support portion 41 for supporting the wafer upright and a base body 42 hermetically sealed on the lower surface of the flange via an O-ring 54. Be mounted. Support part 41
Is a three-point support type in which three bar-shaped wafer support portions 41 are erected on the upper surface of the non-transparent glass body of the sandwich structure 63, and one wafer is supported at three places.
In this case, in the reaction vessel 50, the joint between the flange portion 60 and the vessel main body 52 is vertically extended in an elliptical cylindrical shape so that the portion interposed by the sandwich structure 63 is not heated.

According to this embodiment, since the sandwich structure 63 is located at the portion of the elongated body 55 between the reaction vessel main body 52 and the flange portion 60, heat is not easily transmitted to the flange portion 60. Even if the flange 51 is formed of non-transparent quartz glass as in the prior art, it is possible to effectively prevent high temperature from propagating to the O-ring 54 and other sealing portions. Further, the presence of the sandwich structure 63 makes it possible to equalize the space temperature for the wafer heat treatment in the container body 52. In addition, according to the present invention, since it is integrated with the wafer support device 40 without using an independent heat insulating cylinder, not only the number of parts is reduced but also there is no possibility of generation of particles.

[0024]

As described above, according to the present invention, it is possible to suppress the reaction of a semiconductor wafer without using an independent heat insulating cylinder, suppressing the increase in size of the apparatus, suppressing the generation of particles, and maintaining a high thermal insulation. A container and a heat treatment apparatus using the container can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram corresponding to the invention of claim 1, showing an example of a heat treatment apparatus using the sandwich structure in a flange portion of a reaction vessel.

FIG. 2 is a schematic structural view corresponding to the invention according to claim 4, showing an example of a heat treatment apparatus in which a sandwich structure is incorporated in a wafer support apparatus.

FIG. 3 is a side view of FIG. 2;

FIG. 4 shows a manufacturing procedure of the sandwich structure, and (A)
FIG. 2 is an exploded perspective view, and FIG. 2B is a perspective view showing a sandwich structure.

FIG. 5 is a view showing a schematic configuration of a heat treatment apparatus for a silicon wafer described in the specification of Japanese Patent Application No. 8-24823, which is unknown.

FIGS. 6A to 6C are enlarged views showing the internal structure of a foam used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Semiconductor wafer 50 Reaction container 51 Non-transparent flange 60 Flange part of sandwich structure 61 Non-transparent quartz glass body 62 Quartz glass foam 63 Sandwich structure 40 Supporting device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/324 H01L 21/324 D

Claims (5)

[Claims] 1. A wafer heat treatment reaction vessel for carrying out heat treatment with a semiconductor wafer housed therein, wherein a reaction vessel main body for housing the wafer is formed of a transparent quartz glass body and a flange portion connected to the main body is non-transparent. A reaction vessel characterized by having a sandwich structure of a quartz glass body and a quartz glass foam body having a large number of minute spaces inside. 2. The reaction vessel according to claim 1, wherein the reaction vessel main body is formed of a flat curved body so that a wafer can be stored upright. 3. The non-transparent quartz glass has an apparent density of 0.3.
Composed of 9 g / cm ³ or more bubble-containing quartz glass, reaction container according to claim 1, wherein the quartz glass foam was composed of foamed quartz glass apparent density 0.1 to 0.8 g / cm ^3. 4. A heat treatment apparatus comprising a reaction vessel containing a semiconductor wafer and a support means for supporting a wafer in the vessel, wherein a non-transparent quartz glass body is provided on the non-heat treatment area side of the support means and a large number of fine particles are contained therein. A heat treatment apparatus characterized by comprising a sandwich structure with a quartz glass foam having a space and a quartz thin film stretched vertically and horizontally. 5. The reaction device according to claim 1, wherein said support means is a support means for supporting the semiconductor wafer substantially upright in the container, and said reaction vessel is formed of a flat curved body so as to be able to store the wafer upright. 5. The heat treatment apparatus according to 4.