JP2549302Y2 - Vertical heat treatment equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical heat treatment apparatus for heat treatment of a wafer, a quartz glass substrate for liquid crystal, and the like.
The present invention relates to a vertical heat treatment apparatus including a holder for vertically disposing the substrates and the like, an inner cylinder surrounding the holder, and an outer cylinder for housing the inner cylinder.

[0002]

2. Description of the Related Art In performing heat treatment on a plurality of semiconductor wafers, a vertical heat treatment apparatus has been widely used. That is, in the vertical heat treatment apparatus, the longitudinal axis of the heat treatment tube is arranged to extend in the vertical direction, a plurality of semiconductor wafers are housed in the heat treatment tube by the holder, and while flowing a predetermined gas between the semiconductor wafers, A temperature of 600 to 1200 by a heating source such as an electric heater or a lamp heater disposed outside the heat treatment tube.
° to perform heat treatment. According to such a vertical heat treatment apparatus, it is possible to eliminate the generation of particles or dust due to sliding between the heat treatment pipe and the holding body or the boat, as compared with the conventional horizontal heat treatment apparatus.
Furthermore, it has many advantages such as space saving.

However, if the heat treatment tube is extended in order to increase the number of processed semiconductor wafers in response to a demand for mass production, there arises a problem that the temperature distribution in the longitudinal axis direction and the flow of the processing gas tend to be non-uniform. Therefore, for example, in Japanese Patent Application Laid-Open No. 61-22634, the heat treatment tube is rotated with respect to a heating source to obtain a temperature distribution between wafers.
In addition, the holding body is configured so that a large number of wafers can be arranged at an angle, the wafer is supported by static friction due to gravity, and is configured to be rotatable integrally with the heat treatment tube.

Further, for example, in Japanese Patent Application Laid-Open No. 61-27625, a heat treatment is performed while tilting a wafer at a predetermined angle with respect to a plane perpendicular to the longitudinal axis and rotating the wafer substantially along the perpendicular plane. Make up. According to such a configuration, since the wafer can be rotated with the wafer inclined, a turbulent flow is generated near the wafer, and the processing gas can be uniformly applied. It is stated that the turbulence effect can be obtained by inclining the wafer by 1 to 45 °, more preferably 1 to 20 °.

[0005]

However, as the diameter of the member to be heat-treated becomes larger as in recent years, or the material of the member to be heat-treated, the problem of deformation of the member to be heat-treated at its high temperature under its own weight becomes apparent. did. For example, in a process for forming a thin film on a semiconductor wafer by using a processing gas, it is impossible to support the entire surface of the wafer instead of supporting the peripheral edge of the wafer due to the requirements of the product. The deformation at the center of the wafer leads to a defect in the formed thin film. In view of the drawbacks of the prior art, the present invention achieves a uniform temperature distribution and a predetermined gas flow required for a member to be heat-treated disposed in a heat-treatment tube,
While achieving the homogeneity of the generated thin film on the upper and lower surfaces of the plate member to be heat-treated, the deflection between the peripheral supporting portion and the central portion of the plate member that occurs during the heat treatment process is eliminated, and the diameter of the plate member is increased. An object of the present invention is to provide a vertical heat treatment apparatus that can be used.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned technical problems, the present invention provides a holding member in which a plurality of circular or square plate members are vertically stacked, and a cross section surrounding the holding member is circular. In a vertical heat treatment apparatus that performs a heat treatment while flowing a predetermined gas from above the outer furnace tube and flowing gas between the plate members, the plate member is set to a range of 40 degrees to 70 degrees. The predetermined gas is arranged so as to be inclined substantially upright, and the predetermined gas is configured to be able to flow from the upper side to the lower side of the plate member along the gap between the circular outer furnace tube and the plate member in the direction of inclination. We propose a vertical heat treatment apparatus characterized by the following. The holding body and an inner cylinder surrounding the holding body are installed in the middle between the outer furnace tube and the holding body, and the inner cylinder is inclinedly disposed on an inner wall of the inner cylinder and the holding body. This also includes the case where the plate member is formed in an elliptic cylinder or a rectangular cylinder having a substantially uniform distance from the outer periphery. The present invention also includes a case in which the inner cylinder and the holding member installed inside the inner cylinder are integrally rotatable. Further, the inner cylinder may be provided with a plurality of through holes having an inclination angle substantially equal to the inclination angle of the disk member.

[0007]

According to such a technical means, the plate member to be heat-treated can be inclined upright, so that the deformation at the central portion of the plate member whose peripheral edge is supported can be reduced. However, when the inclination angle is too large, it is difficult to arrange the plate members on the holder, and it is difficult to store a large number of the plate members in the holder. It is possible that the concentrations of the processing gases are not the same and the resulting thin films differ. Conversely, if the angle of inclination is too small,
The expected effect cannot be obtained, and the above-mentioned deformation due to its own weight may exceed the limit required for the product. In the present invention, experiments were conducted on the material, shape and dimensions of the members to be heat-treated, and the heat treatment temperature, and the range of the inclination angle was obtained from 40 to 70 °.

Further, according to the technical means, since the inner cylinder is formed to have a shape conforming to the projected shape of the plate member to be heat-treated which is housed in an inclined manner, a passage from the inner cylinder to any of the plate members is provided. By providing a plurality of through-holes at substantially the same angle as the plate member, the predetermined gas can be made to flow uniformly to the plate member. . Further, since the inner cylinder and the holding member installed inside the inner cylinder are integrally rotatable, the plate member to be heat-treated accommodated in the inner cylinder also rotates with respect to a heating source, so that the plate members are interlocked with each other. In this case, the heating temperature can be made uniform.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely described. It is only an example.

FIGS. 1 to 4 show a vertical heat treatment apparatus according to an embodiment of the present invention. The apparatus according to one embodiment shown in FIGS. 1 and 2 comprises a base 10 on a disk and a cylindrical bell-shaped external furnace tube provided on the base 10 and provided with a gas inlet 21 at the top end. 20; a plurality of lamp heaters 60 surrounding the outer furnace tube 20 for heating the outer furnace tube 20; and a center of the base 10 in the outer furnace tube 20 concentrically with the outer furnace tube 20, respectively. A turntable 12 rotatably mounted on a rotary shaft 19 penetrating the rotary table, and a heat retaining cylinder 70 mounted on the turntable 12
And an inner cylinder 3 erected on the turntable 12 and having an elliptical cross section.
And a plurality of through-holes 31 formed on one side surface of the inner cylinder 30 at a predetermined inclination angle, and a support rod 41 disposed in the inner cylinder 30 and standing on the heat retaining cylinder 70, Each member except the lamp heater 60 is formed of a quartz glass material.

Next, each of these members will be described in detail. The rotary table 12 is provided with a processing gas vent 13,
The base 10 has a processing gas passage 14 along a rotation axis 19.
Is provided, and further, an exhaust hole 11 penetrating the base 10 is provided,
By connecting a suction pump (not shown) to the downstream side, the wafer 5 is introduced into the reaction chamber 23 from the gas inlet 21, passes through a plurality of through holes 31 provided in the inner cylinder 30, and
The processing gas after contacting the upper and lower surfaces of the first processing gas 1 can be exhausted from the exhaust hole 11.

The outer furnace tube 20 is formed in a cylindrical bell shape using a transparent quartz glass material having a low infrared absorption.
A pressure-resistant sealing means 22 is interposed on the opening side in contact with the base 10 to form a sealed space inside the reaction chamber 23, and the reaction chamber 23 can be opened using a lifting member (not shown).

The inner cylinder 30 is made of a translucent quartz glass material containing air bubbles in order to obtain a predetermined heat uniformity, and is formed into an elliptical cylinder having upper and lower ends open. A large number of through holes 31 having an inclination angle of? Are formed so that the processing gas can enter the inner cylinder 30 through the through holes 31 in one direction. An elliptical lid 32 is provided to prevent the processing gas from directly entering from the upper opening of the inner cylinder 30. In this case, after the holding body 40 is installed in the inner cylinder 30, the lid 32 may be installed on the upper surface thereof.
The lid 32 may be fixed to itself. Further, as shown in FIG. 2, the cross-sectional shape of the inner cylinder 30 is an elliptical shape similar to a projected shape in which a wafer 51 to be stored is tilted upright at a predetermined tilt angle α.

The holding body 40 is composed of three support rods 41, 42, 43 connecting the ceiling plate and the bottom plate along the axial direction (see FIG. 2). The holding groove 44 of the wafer 51 is engraved at a predetermined angle, and the wafer 51 fitted and held in the holding groove 44 has a predetermined angle (α = 40 to 70).
°) to be able to be stacked vertically. A through hole 31 formed at the predetermined angle is provided on one side surface of the inner cylinder 30 facing the upper end portion where the wafer 51 is inclined and raised.
Are arranged in such a manner that the processing gas that has passed through the through hole 31 and entered the inner cylinder 30 flows substantially along the inclined upper and lower surfaces of the wafer 51.

FIGS. 3 and 4 show a holder 45 of a vertical heat treatment apparatus according to another embodiment. The holder 45 has a holding groove 44 for supporting a square quartz glass substrate 52. And support rods 46, 47, 48, 49 having
The holding body 45 has an inner cylinder 35 having a substantially rectangular cross section.
(Not shown). The cross-sectional shape is the inclination angle α
This is similar to the projected shape of the quartz glass substrate 52 that is inclined and raised.

Next, in such a configuration, a preferable inclination angle α
The quartz glass substrate 5 is used as the plate member to be heat-treated.
2 will be described. The dimensions of the quartz glass substrate 52 are 1.5 mm in thickness and 200 × 2 in size.
The substrate 52 is stacked on the quartz glass substrate 5 while the processing gas flows at a constant flow rate in the vertical heat treatment apparatus.
The heat treatment was performed at a temperature of 1100 ° C. for 4 hours while rotating integrally with the substrate 2. Here, the substrate 52 was tilted upright with the tilt angle α in the range of 0 to 80 °, and the heat treatment was repeatedly performed under the above conditions. After the heat treatment, the quartz glass substrate 52 is taken out of the heat treatment apparatus and allowed to cool, and then the deflection Δh (μm) between the periphery and the center of the quartz glass substrate 52 is performed.
And the thicknesses of the thin films formed on the upper and lower surfaces of the quartz glass substrate 52 are measured, and their difference (μm) is obtained. The results of the heat treatment are shown in the table of FIG.

According to this embodiment, if the inclination angle is less than 40 °, the deflection Δh from the peripheral edge of the substrate toward the central portion is obtained.
Exceeds the minimum deflection required as a product, and as the inclination angle increases, the deflection Δh decreases. In particular, when the inclination angle is set to 70 ° or more, the measurement becomes so small that measurement is impossible. On the other hand, looking at the difference in the thickness of the thin films formed on the upper and lower surfaces of the quartz glass substrate, when the inclination angle exceeds 70 °, the thickness difference becomes unacceptable as the quality of the thin film, especially when the inclination angle is 80 °. On the other hand, the thickness of the upper surface side is as large as 8 μm as compared with the thickness of the formed thin film on the lower surface side of the quartz glass substrate, and cannot be used as a product. From the above embodiment, if the inclination angle α is small, the deflection Δh becomes large, and conversely, if the inclination angle α is excessively increased, the thickness of the thin film formed on the upper and lower surfaces is not uniform. Turned out to be unacceptable. In the present embodiment, the inclination angle is 40 to 70.
Within the range of °, a suitable result can be obtained.

[0018]

As described above, according to the present invention, it is possible to reduce the heat treatment defects due to the bending deformation due to the weight of the plate member or the residual stress while maintaining the uniformity of the formed thin film on the upper and lower surfaces of the plate member to be heat treated. I can do things. According to the present invention, the space saving of the conventional vertical heat treatment apparatus,
Advantages such as suppression of dust and particle generation and good operability can be maintained as they are. And so on.

[0019]

[Brief description of the drawings]

FIG. 1 is an overall sectional front view of a vertical heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional plan view of the vertical heat treatment apparatus according to the embodiment of the present invention.

FIG. 3 is a perspective view of a holder according to another embodiment of the present invention.

FIG. 4 is a partial side view of a holder according to another embodiment of the present invention.

FIG. 5 is a table showing the relationship between the inclination angle, the deflection of the plate member to be heat-treated, and the difference between the thicknesses of the formed thin films on the upper and lower surfaces according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 12 rotating table 19 rotating shaft 20 outer furnace tube 30 inner cylinder 31 through hole 40 holder 45 holder 51 wafer 52 quartz glass substrate

Claims (4)

(57) [Scope of request for utility model registration] 1. A holding body in which a plurality of circular or square plate members are vertically stacked, and an outer furnace tube having a circular cross section surrounding the periphery of the holding member, wherein a predetermined gas is provided from above the outer furnace tube. In a vertical heat treatment apparatus for performing heat treatment while flowing a gas between the plate members, the plate member is disposed so as to be inclined substantially upright in a range of 40 degrees to 70 degrees, and the predetermined gas is used for the predetermined gas. A vertical heat treatment apparatus characterized in that it is configured to be able to flow from the upper side of the plate member to the lower side thereof along the gap between the circular outer furnace tube and the plate member in the direction of inclination. 2. The holding body and an inner cylinder surrounding the holding body are provided between the outer furnace tube and the holding body.
2. The vertical heat treatment apparatus according to claim 1, wherein the inner wall of the inner cylinder is an elliptical cylinder or a rectangular cylinder having a substantially uniform distance between the outer periphery of the plate member inclinedly disposed on the holder. 3. The vertical heat treatment apparatus according to claim 2, wherein said inner cylinder and said holding member installed inside said inner cylinder are integrally rotatable. 4. The inner cylinder is provided with a plurality of through holes having an inclination angle substantially the same as the inclination angle of the disk member.
Vertical heat treatment equipment