JPH0590940U - Vertical heat treatment equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is capable of easily controlling a temperature in a heat treatment of a glass substrate such as a semiconductor wafer or a liquid crystal, forming a stable soaking zone, and maintaining the strength of a boat. Provided is a vertical heat treatment apparatus capable of efficiently heat-treating a large number of wafers and the like. According to the present invention, a plate-like end plate is provided on the lower surface side of a plurality of support grooves engraved with supporting grooves for laminating and supporting the wafers, and a hollow body filled with quartz wool or quartz foam is provided on the upper surface side. A vertical heat treatment apparatus is provided, which is equipped with a vertical jig made of quartz glass, each of which is fixedly mounted and whose wall thickness is set to be smaller than the wall thickness of the heat insulating cylinder.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vertical heat treatment apparatus for heat-treating glass substrates such as semiconductor wafers and liquid crystals, and in particular, a vertical quartz glass storage jig that can be installed on a heat retaining cylinder arranged at the bottom of a core tube. The present invention relates to a vertical heat treatment apparatus.

[0002]

[Prior Art]

 Conventionally, a support boat in which semiconductor wafers are stacked is housed in a quartz glass furnace core tube surrounding a heating means, and a semiconductor wafer mounted on the support boat is predetermined by the heating means. A heat treatment apparatus for performing various heat treatments such as oxidation, diffusion, vapor phase growth, and annealing of a semiconductor wafer surface area by flowing a reaction gas or an inert gas to the semiconductor wafer surface area while heating and controlling the temperature area is known. In this type of heat treatment equipment, in order to reduce the installation area, a vertical type heat treatment furnace in which the core tube is erected vertically is frequently used, but in such equipment, it is formed in the wafer surface area. Alternatively, in order to prevent variations in the thickness of the thin film to be injected and the distribution of impurity concentration, a quartz glass heat insulating tube is placed between the heating area in the furnace core tube 2 and the furnace core tube opening end side to perform the wafer heat treatment. Space The heating means 1 surrounded by the furnace core tube is positioned above the heat insulation tube, and the heat insulation tube functions as a heat insulating material, so that it is provided on the open end side of the furnace core tube 2. It also prevents the high temperature from propagating to the O-ring and other sealing parts.

In such a conventional device, heat insulation and the like are arranged on the lower side of the support boat, but on the upper side of the boat, a thin plate that supports a plurality of columns with engraved support grooves for stacking and supporting wafers and the like is formed. Only the disk is provided, and the heat retention state in the upper part of the boat is not always perfect, so that the soaking length in the heat treatment area is disturbed, and therefore the wafer near the upper part of the boat is not always required. High-quality heat treatment could not be performed and was often discarded as a defective product.

In order to solve such a drawback, in JP-A-60-140817, as shown in FIG. 2, quartz wool is filled from above the wafer storage jig 30 installed on the heat retaining tube 34 of the furnace core tube 37. A technique has been proposed in which a cap 39 having a quartz container 32 is configured to seal a core tube, thereby preventing heat in the core tube 37 from escaping upward.

[0005]

[Problems to be solved by the device]

 However, in the above-mentioned conventional technique, since the quartz container 32 and the upper surface of the storage jig 30 have to be arranged with a space between them, the total length of the storage jig 30 is shortened accordingly, and the number of wafers that can be stacked is reduced. Basically, since it is not possible to maintain a predetermined soaking zone without heating up to the lower surface of the quartz container 32, the length of the soaking section is substantially shorter than the length of the heater 35, and the efficiency of the soaking section is reduced. descend. Further, since the core tube 37 is divided into the cap 39 and the body portion and the quartz container 32 is attached to the lower surface, it is difficult to provide the gas inlet on the upper surface side of the cap 39. However, the device configuration becomes complicated.

In view of the above drawbacks of the prior art, the present invention makes it possible to easily control the temperature in a heat treatment of a glass substrate such as a semiconductor wafer or a liquid crystal, to form a stable soaking zone, and to improve the strength of the boat. It is an object of the present invention to provide a vertical heat treatment apparatus capable of maintaining and efficiently heat-treating a large number of wafers and the like.

[0007]

[Means for Solving the Problems]

 In order to achieve the above technical problems, the present invention has a plate-like end plate on the lower surface side of a plurality of support grooves engraved with supporting grooves for laminating and supporting the above-mentioned wafers, and quartz wool or quartz on the upper surface side. A vertical heat treatment apparatus characterized in that a hollow body filled with foam is fixedly provided, and a vertical quartz glass storage jig is provided in which the hollow body wall thickness is set to be smaller than the heat insulation cylinder wall thickness. To propose.

[0008]

According to such a technical means, the hollow body functions as an upper heat retaining cylinder because it is filled with quartz wool or quartz foam, and as a result, the hollow jig is provided on the upper and lower sides of the storage jig for stacking and supporting wafers and the like, respectively. Since the heat insulation cylinder is located, a stable soaking zone can be secured without heat escaping from the top. Further, in this conventional technique, since the upper heat retaining tube is fixed directly to the storage jig, both the lower heat retaining tube and the upper heat retaining tube are closely attached to the storage jig. As a result, the core tube It is possible to set the storage jig length to the limit of the effective length of the storage jig, and the number of wafers that can be loaded is significantly increased compared to the above-mentioned conventional technique. There is no needless heat loss and the thermal efficiency increases. Further, the conventional core tube can be used as it is without dividing the core tube into the cap and the body portion, which leads to simplification of the apparatus configuration.

Since the heat has a heat gradient from the upper side to the lower side, there is no difference in the heat retaining ability even if the wall thickness of the upper heat retaining cylinder (hollow body) is set smaller than the wall thickness of the lower heat retaining cylinder. Focusing on this, the above-mentioned structure is taken. As a result, it is possible to reduce the gravity load applied to the support columns, to obtain a storage jig that does not have a fear of strength, and also to secure the strength that enables stacking and arrangement of a large number of wafers.

Also, in a particularly preferred embodiment, the hollow body is arranged so as to be located at the upper edge side of the heater heating area surrounded by the core tube or at an area outside the heating area. Even if it is hermetically sealed, it will not be broken or damaged. This is preferable because the heat insulating material in the hollow body does not scatter to the outside of the hollow body to cause generation of particles.

Further, it is preferable that air bubbles are mixed into the hollow body so as to be semitransparent or opaque so that the outer hollow body itself can have a heat retaining effect.

As a technique similar to the present invention, Japanese Patent Laid-Open No. 3-257821 discloses a support boat in which thick-walled solid cylindrical bodies are fixedly installed on both upper and lower sides of a column. Since the technology is silicon carbide, which has a smaller heat capacity than quartz, it does not function as a heat insulating cylinder and is a technology that is similar to the present invention, but the boat is made of quartz glass. However, the following problems still occur. That is, since the cylindrical body is solid, the weight burden is large, and if it is silicon carbide, it is not necessary, and if it is quartz glass, the strength is a serious problem. For this reason, a technique in which a through hole is opened is also disclosed, but if such a configuration is adopted, the effect as a heat insulating cylinder is greatly reduced. The upper and lower cylinders have the same thickness, and no consideration is given to the thermal characteristics in this aspect. Therefore, the present invention cannot be created from such conventional technology.

[0013]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the invention thereto, but merely illustrative examples. Nothing more. FIG. 1 is a vertical sectional view of a vertical heat treatment apparatus according to an embodiment of the present invention. In the figure, 3 is a cylindrical dome-shaped core tube that can be installed on the base 4, and wafers are stacked inside the core tube 3 via the heat insulation tube 2 at the center of the base 4. The vertical storage jig 1 is installed. On the other hand, a spiral tubular heating element 5 is surrounded around the core tube 3 corresponding to the installation position of the vertical storage jig 1 so that high frequency heating is possible.

On the other hand, a gas inlet pipe 22 is arranged above the core tube 3, and a gas outlet pipe 21 is arranged on the peripheral surface of the core tube 3 below the position where the heating element 4 is surrounded. After being contacted with the surface of the wafer through the slit gap of the storage jig 1, the processing gas introduced from the above can be discharged to the outside through the outlet pipe 21. The base 4 is installed on a rotatable drive shaft 6 and is configured to be rotatable integrally with the core tube 3 in the arrow direction.

Next, the heat insulation cylinder 2 and the storage jig 1 which are the main components of the present invention will be described. The heat insulating cylinder 2 is formed of a transparent quartz glass cylindrical body 20 having an outer diameter slightly smaller than the inner diameter of the furnace core tube 3, and has a flat surface on which the storage jig 1 can be mounted, and inside, A heat insulating body composed of a quartz glass plastic body 23 having a large number of fine bubbles and a surrounding body 24 made of transparent quartz glass surrounding the periphery is filled. Next, the manufacturing procedure of the heat retaining body will be described.First, quartz fine powder is put into a quartz crucible having an opening at the upper side and having the same shape as the surrounding body and only a large height, and 1300 to 1600 in a vacuum furnace. By heating at a temperature of around ℃, a so-called foam glass-like plastic body having a large number of minute spaces inside and a quartz thin film stretched vertically and horizontally is formed. At this time, it is preferable that foamed glass-like plastic body 31 having a larger number of vacuum microspaces can be formed by heating the quartz fine powder with water mixed with carbon powder in a mud-like state to heat it. Then, the surface of the plastic body 23 thus formed is melted by heat to form the thin film surrounding body 24.

The storage jig 1 is made of quartz glass and has a lower end plate 11 having an outer shape slightly larger than the outer shape of the wafer 10 and a semi-circular side end plate of the end plate 11 which is placed upright from the peripheral edge thereof. It is composed of a plurality of columns 13 in which wafer supporting grooves 12 are engraved at a pitch interval corresponding to the wafer pitch interval, and a cylindrical hollow body 15 fixed on the columns 13 and having the same diameter as the end plate. .. Unlike the heat retaining cylinder 2, the hollow body 15 is formed of an opaque glass cylindrical body 15 containing air bubbles therein, and has a large number of minute air bubbles therein, like the heat retaining cylinder 2. A heat retaining body composed of a quartz glass plastic body 23 and a surrounding body 24 made of transparent quartz glass surrounding the periphery thereof is filled and sealed. The height of the support column 13 is set so that the upper surface of the heat retaining cylinder 2 is substantially aligned with the lower end of the heating element 5, while the lower surface of the hollow body 15 is substantially aligned with the upper end of the heating element 5.

According to this embodiment, since the hollow body 15 and the heat insulating cylinder 2 are located in a region slightly deviated from the upper and lower boundary regions of the heating region of the heating element 5, quartz glass containing bubbles is included. Even if it is formed by the cylindrical body 151 made of stainless steel, or even if the plastic body 23 having fine bubbles is hermetically sealed, the damage of the present invention can be achieved smoothly, and the hermetically sealed structure is achieved. In addition, it is possible to completely prevent the generation of particles from the hollow body.

Further, according to the above-mentioned configuration, the soaking section, which is a wafer heat treatment region inside the core tube 3, has a predetermined temperature of 1100 ° C. to 1200 ° C. ± α ° C. controlled temperature by the heating element 5 surrounding the core tube 3. The heat-treated region of the controlled and uniform high temperature wafer is formed. In such a stable and uniform temperature distribution state, for example, precise temperature control necessary for diffusion treatment can be performed, and high quality heat treatment can be performed.

[0019]

[Effect of the device]

 As described above, according to the present invention, in the diffusion heat treatment of the semiconductor wafer by the vertical heat treatment apparatus, the heat insulating hollow body is integrally fixed on the upper part of the storage jig installed in the lower heat retaining cylinder. It is possible to easily achieve uniform temperature distribution in the wafer processing area, and since the lower heat retaining cylinder and the upper heat retaining cylinder are closely arranged on the upper and lower sides of the storage jig, the soaking area is limited to the total length of the storage jig. It can take one cup and heat-treat many wafers efficiently. Also, although an upper heat retaining body (hollow body) is attached to the upper part of the storage jig 1, since the heat retaining body is hollow and is formed thinner than the lower heat retaining body, strength is maintained and a large number of semiconductor wafers are kept. Can be heat-treated efficiently. It has various remarkable effects.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of a vertical heat treatment apparatus according to a conventional technique.

[Explanation of symbols]

 15 Hollow body 10 Semiconductor wafer 1 Storage jig 2 Thermal insulation tube 3 Core tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Chie Yokoi, 1 No. 3, Kayoya-cho, Takefu-shi, Fukui Prefecture 4 No. 1 Fukui Shinetsu Quartz Co., Ltd. (72) Yoko Higashikawa, No. 3 Kayoya-cho, Takefu-shi, Fukui Prefecture 4 Fukui Shin-Etsu Quartz within (72) Inventor Michiko Morishita No. 3 Kayoya-cho, Takefu-shi, Fukui Prefecture 4 4 Fukui Shin-Etsu Quartz within (72) Inventor Naoki Tokunaga No. 3 Kayutani-cho, Takefu-shi, Fukui 4 Fukui Shin-Etsu Quartz Co., Ltd.

Claims (3)

[Scope of utility model registration request] 1. A vertical type which is installed on a heat-retaining cylinder arranged at the bottom of a core tube and is configured to be capable of stacking plate-like bodies (hereinafter referred to as wafers) such as semiconductor wafers and glass substrates such as liquid crystal (hereinafter referred to as wafers) in a vertically stacked manner In a vertical heat treatment apparatus equipped with a storage jig, plate-like end plates are provided on the lower surface side of a plurality of support columns engraved with supporting grooves for stacking and supporting the wafers, and quartz wool or quartz foam is provided on the upper surface side. A vertical heat treatment apparatus, characterized in that each of the filled hollow bodies is fixedly provided, and a vertical quartz glass storage jig is provided in which the hollow body wall thickness is set to be smaller than the heat retaining cylinder wall thickness. 2. The vertical heat treatment apparatus according to claim 1, wherein the hollow body is arranged at an upper edge side of a heater heating region surrounded by a core tube or a region outside the heating region. 3. The vertical heat treatment apparatus according to claim 1, wherein air bubbles are mixed into the hollow body to make it semitransparent or opaque.