JP2953744B2 - Heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a heat treatment apparatus.

(Prior art) In order to widen the soaking area in a horizontal annular furnace used for a conventional diffusion furnace or the like in which a predetermined process is performed, a winding at a central portion in an intermediate portion excluding both end portions of the annular furnace is used. Japanese Patent Application Laid-Open No.
There is Japanese Patent No. 114032.

Japanese Utility Model Application Laid-Open No. 61-89800 discloses a configuration in which a heating wire is held in a cylindrical recess formed by two groove recesses such as ceramics.

Japanese Patent Application Laid-Open No. Sho 60-24 / 1995 discloses a composite structure heater in which a heating wire wound in a coil shape at a fixed interval is provided in a refractory heat insulating material.
There is a 6582 publication.

(Problems to be Solved by the Invention) In the technology of the former document, in order to widen the desired soaking area,
For example, when the inner diameter of the heat treatment unit of the heat treatment device changes,
Alternatively, when the length of the process tube inserted into the heat treatment apparatus changes, or when the heat insulation method at the furnace port of the heat treatment apparatus changes, the winding density of the heating wire in the center of the heat treatment apparatus is reduced to 5 to 15%. It is necessary to set optimally within the range.

The heating wire holding method described in the following document discloses a method of holding a plurality of sets of heating wire holding members each having a cylindrical recess formed by two groove-shaped recesses made of, for example, ceramics.
A set of 0 windings is configured so that the predetermined winding pitch does not change even if the heating wires are de-energized and thermal expansion and contraction are repeated.

Therefore, every time the winding density is changed, several hundred sets of holding members made of, for example, ceramics having different dimensions must be used. This holding member has a complicated shape, and is usually manufactured by firing ceramics or the like using a mold, and has a problem that it takes a lot of cost and time to manufacture a set of holding members. .

A heat treatment apparatus in a desired heating area can be configured by arranging a large number of composite structure heaters composed of the heating wire and the refractory heat insulating material of the latter document.

However, since a large number of heating zones, for example, ten, are provided in order to widen the soaking area in the heat treatment apparatus, when controlling the temperature of each heating zone independently, the heating zones adjacent to each other are affected. There is a problem that stable temperature control is difficult.

The present invention has been made in view of the above points, and is intended to obtain a desired temperature distribution characteristic of a heat treatment apparatus without using a heating wire holding member manufactured by firing ceramics or the like using a mold or the like in advance. Another object of the present invention is to provide a heat treatment apparatus that can easily and easily change the winding density of a heating wire, set a desired heating density, obtain the desired temperature distribution characteristics, and have good temperature stability.

[Configuration of the invention]

(Means for Solving the Problems) In the heat treatment apparatus according to claim 1 of the present invention, a coil-shaped heating wire is provided around an inner wall of a tubular heat-resistant and heat-insulating member around a tubular reaction tube accommodating an object to be processed. In the heat treatment apparatus provided with a heating unit provided with a groove, a groove for holding the heating wire is provided on the inner wall of the heat-resistant and heat-insulating member, the heating wire is constituted by at least three zones, and the heating wire is heated in the groove. Provide the winding pitch in the lower zone more densely than the other zones, provide an inner cover made of a good heat conducting member on the outer periphery of the heat-resistant heat insulating member, and provide an outer cover on the outer periphery of this inner cover via a cooling unit. A metal face plate joined to an inner cover and an outer cover is provided at an opening end on the furnace port side of the heat-resistant and heat-insulating member.

According to a second aspect of the present invention, in the heat treatment apparatus of the first aspect, a power supply terminal portion is fixed to the outer cover via an insulating member, and the heating wire is electrically connected to the power supply terminal portion. It is characterized by having been done.

According to the heat treatment of the first aspect, a groove for holding the heating wire is provided on the inner wall of the heat-resistant and heat-insulating member, the heating wire is constituted by at least three zones, and the temperature of the heating wire is reduced in the groove. Since the winding pitch in the zone is set to be denser than in other zones, the heating wire is provided on the inner wall of the heat-insulating member in a state where the winding density of the desired area is changed without using a special heating wire holding member. As a result, desired temperature distribution characteristics can be obtained, and the soaking region can be expanded and the temperature stability can be improved. Moreover, since an outer cover made of a good heat conducting member is provided on the outer periphery of the heat resistant heat insulating member, and a metal face plate joined to the inner cover and the outer cover is provided at the opening end of the heat resistant heat insulating member on the furnace port side, The heat-resistant and heat-insulating member can be effectively cooled without using an air-cooling means, so that the size of the apparatus can be reduced, and the insulation resistance of the heat-resistant and heat-insulating member can be kept high to suppress the leakage current.

According to the heat treatment apparatus of the present invention, a power supply terminal portion is fixed to the outer cover via an insulating member, and the heating wire is electrically connected to the power supply terminal portion. The displacement of the heating wire and the power supply terminal due to external force can be prevented, and the durability of the heating wire and its joint with the power supply terminal can be improved.

(Example) An example in which a heat treatment apparatus according to the present invention is applied to a diffusion furnace for batch processing semiconductor wafers will be specifically described with reference to the drawings.

In FIG. 2, the coil-shaped resistance heating wire 1 is, for example, Fe.
Made of Cr-Al alloy, wire diameter A = 2mm, coil diameter B =
It is configured to have a coil interval (winding pitch) of 12 mm and C = 10 mm.

In FIG. 1, for example, a cylindrical heat-resistant and heat-insulating member 3 having a height of 1000 mm and an inner diameter of 350 mm for fitting or embedding and holding the coil-shaped heating wire 1 in a groove 2 provided on the inner wall surface is made of, for example, ceramic fiber and alumina cement. Even if the heating wire 1 is energized and generates heat by mixing, the coil-shaped heating wire 1 and the heat-resistant heat insulating member 3 are mixed and heat-treated.
As shown in FIG. 3, a gap 4 is provided above the entire groove 2 so that a predetermined interval is left therebetween, and the heating section is configured as described above.

The heat-resistant and heat-insulating member 3 is configured to be surrounded by a heat-insulating material 5 such as an alumina blanket and an inner cover 6 made of a good heat-conductive member such as aluminum.

A cooling unit 7 is provided on the outer periphery of the inner cover 6, and the cooling unit 7 is formed by a cooling pipe 8 made of, for example, a copper pipe through which cooling water flows as shown in FIG. It is arranged in.

A cylindrical outer cover 9 made of a good heat conducting member such as aluminum is provided so as to surround the cooling unit 7.

The heating wire 1 is welded to a terminal screw 11 of a power supply terminal portion 10. The terminal screw 11 is made of, for example, ceramics and has a heat-resistant and insulating property and has a structure capable of being coaxially fitted with each other as shown in FIG. Insulators 12 and 13 as insulating members are connected to two nuts 14
, So as to be held and fixed to the auxiliary plate 15.

The auxiliary plate 15 is attached to the outer cover 9 by four screws 16.

At the lower opening end of the heat-resistant and heat-insulating member 3, a substantially same hole as that of the heat-resistant and heat-insulating member 3 is provided, and a face plate 17 made of, for example, stainless steel is provided. The face plate 17, the inner cover 6, and the outer cover 9 are provided. Are attached to the annular members 18 and 19 provided coaxially with the holes of the face plate 17 with screws 20 and 21 at a plurality of places.

A heat-insulating lid 22 having heat-insulating properties is provided at the upper opening end of the heat-insulating member 3. The heat-insulating lid 22 is broken and a stainless steel lid 23 is attached to, for example, a stainless steel upper ring 24. The outer ring 9 is attached to the upper ring 24.

A gap 25 is provided between the inner cover 6 and the upper ring 24 so that a predetermined interval is left even if the inner cover 6 is expanded by thermal expansion.

The heating wire 1 is composed of at least three zones, a first zone having a height of 100 mm between the terminal portions 10A and 10B, a second zone having a height of 750 mm between the terminal portions 10C and 10D shown in FIG. A third zone having a height of 150 mm is provided between the terminal portions 10E and 10F, and a power supply source (not shown) and a control unit appropriately control the power applied to each of the above zones so that a wide uniform temperature range in the heat treatment apparatus can be obtained. It has been.

As shown in FIG. 7, a temperature measuring element, for example, a thermocouple 34, 35, 36 is provided in each of the above zones so as to penetrate the heating section 26, and the temperature inside the heat treatment apparatus can be measured from outside the outer cover 9. ing.

FIG. 6 shows a coil-shaped heating wire 1 between the terminal portions 10C and 10D.
2 shows a state before mounting on the heat-resistant and heat-insulating member 3.

As described above, the terminal portions 10C and 10D are provided at a coil interval C of 10 mm, and the intermediate portion is provided at a coil interval D of 9.5 mm so that the heat generation density is about 5% larger than at both ends.
A straight portion E is provided at a portion where the coil interval changes. By providing the straight portion E, the heating wire is wound into a predetermined number of coil turns, and then the heating wire is connected to a predetermined heating portion F, G, H
, The coil intervals C and D can be easily set.

Next, a method for integrally manufacturing the heat-insulating member 3 and the coil-shaped heating wire 1 will be described below.

The coil-shaped heating wire 1 is covered with a tube made of an elastic organic thin film, and is arranged at a predetermined interval in a mold for molding a heat-resistant and heat-insulating member. Then, the entire space of the mold is filled with a raw material to be a heat-resistant and heat-insulating member after firing, and after this is solidified, released, dried and fired. By this firing, the tube is incinerated and the raw material is fired, so that a heating unit including the heat-resistant and heat-insulating member 3 and the heating wire 1 is manufactured.

Therefore, even in the case where the coil interval is changed, the heat generating portion can be easily manufactured by the same method as described above.

As shown in FIG. 7, a heating plate 26 is arranged by mounting and fixing the face plate 17 on the base 30 at a predetermined interval, and a heating member 26 is disposed on the heating plate 26, for example, a heat-resistant material having an outer diameter of 300 mm and a length of 1200 mm. A process tube 27 made of quartz is inserted and arranged.
A plurality of, for example, 170 silicon wafers 28 are horizontally stored in the process tube 27 in the quartz boat 31, and the boat 31 is placed on the holding table 32. The holding table 32 is placed on the lid 33, and is configured such that the wafer 28 can be loaded and unloaded to a predetermined soaking area of the process tube 27 by the elevating mechanism 29. One end of the process tube 27 is connected to a reaction gas supply pipe (not shown) for supplying a reaction gas, and the other end is connected to an exhaust pump (not shown) for exhausting the inside of the process tube 27 to a predetermined pressure. An exhaust pipe is provided.

Next, the case where the above heat treatment apparatus is heated to 900 ° C. will be described.

The wafer 28 is carried into the process tube 27, a predetermined reaction gas is supplied, and the reaction gas is exhausted to a predetermined pressure by the exhaust pump. A power supply source (not shown) and a control unit are connected to each of the heating wires 1 of the three zones, and the control unit measures the temperatures of the thermocouples 34, 35, and 36, and the power applied to the heating wires 1 Is appropriately controlled.

FIG. 8 shows the temperature distribution of the vessel having the longest soaking range in the process tube 27 at this time.

 The soaking length within 900 ℃ ± 1 ℃ is 770mm.

Next, FIG. 9 shows a temperature distribution in the case where the coil interval shown in FIG. 6 is the same as C = 10 mm and D = 10 mm, and the longest soaking range is obtained.

The soaking length at 900 ° C ± 2 ° C is 760 mm, and the temperature error is large.

When the temperature error is within 900 ° C. ± 1 ° C., the soaking length is as short as 680 mm as shown in FIG.

The reason why the temperature distribution is not constant when the coil interval is constant as shown in FIG. 9 will be described below.

In the cylindrical heat treatment apparatus having an open lower end as in the above-described embodiment, a heat dissipation kerf that dissipates a large amount of heat to the lower end and shows heat radiation at a location in the process tube 27 is processed as shown in the lower part of FIG. The heat dissipation increases on the left side of the drawing, which is the lower end side of the tube 27.

As shown in the upper part of FIG. 1, the heating amount of the third zone provided on the lower side of the heat treatment apparatus is large in the heating curve of each heating zone when the heat equalizing area is widened by the heat treatment apparatus. Even if an attempt is made to equalize the temperature inside the furnace by applying a large amount of heat to such a large heat dissipation, the temperature is not equalized but a temperature error increases at the lower end. Therefore, the winding pitch of the heating wires is increased so that the temperature dropping portion in FIG. 9, that is, the heating portion G in the second zone in FIG. 8 generates approximately 5% more heat than the other heating portions F and H. This is an example of the present invention, and good heat equalizing characteristics are obtained as shown in FIG.

The relationship between the position of the heat generating portion G where the heat density is large and the coil interval C and D which can take a long soaking range depends on the length of the heat treatment furnace,
Since it varies depending on the diameter, the mounting method of the process tube, the flow rate of the processing gas, and the like, it may be appropriately determined according to the use conditions.

As described above, since the present invention does not use a specially shaped ceramic block or the like that holds the heating wire 1, it is possible to supply the heat treatment apparatus at a low cost and easily with a short delivery time.

In addition, the heating section including the heat-resistant and heat-insulating member 3 and the heating wire 1 using the above-described embodiment is not limited to a cylindrical and integrated body, and a cylindrical heating section as shown in FIG. 12 may be connected coaxially.

Further, as shown in FIG. 13, a semi-cylindrical heating section may be connected in a cylindrical shape.

Further, the heating wire 1 is not limited to a circular coil shape, but may have any shape such as an elliptical shape.

The present invention is not limited to the above embodiment,
Various implementations are possible within the scope of the present invention. In the above embodiment, the present invention is applied to a vertical heat treatment apparatus in which the lower end side of the heat treatment apparatus is opened. However, the present invention may be applied to a horizontal heat treatment apparatus in which both sides of the heat treatment apparatus are opened.

The heat treatment apparatus according to the present invention can be used for a CVD apparatus, an oxidation diffusion apparatus, or the like, or a plasma apparatus used in a semiconductor manufacturing apparatus, a liquid crystal manufacturing apparatus, or the like.

〔The invention's effect〕

According to the heat treatment according to claim 1 of the present invention, a groove for holding a coil-shaped heating wire is provided on the inner wall of the heat-resistant and heat-insulating member,
The heating wire is constituted by at least three zones, and the heating wire is provided in the groove with a winding pitch in the temperature reduction zone denser than other zones, so that no special heating wire holding member is used. The heating wire can be provided on the inner wall of the heat-resistant and heat-insulating member in a state where the winding density of the desired region is changed, so that a desired temperature distribution characteristic can be obtained, and the soaking region can be expanded and the temperature stability can be improved. Moreover, since an outer cover made of a good heat conducting member is provided on the outer periphery of the heat resistant heat insulating member, and a metal face plate joined to the inner cover and the outer cover is provided at the opening end of the heat resistant heat insulating member on the furnace port side, The heat-resistant and heat-insulating member can be effectively cooled without using an air-cooling means, so that the size of the apparatus can be reduced, and the insulation resistance of the heat-resistant and heat-insulating member can be kept high to suppress the leakage current.

According to the heat treatment apparatus of the present invention, a power supply terminal portion is fixed to the outer cover via an insulating member, and the heating wire is electrically connected to the power supply terminal portion. The displacement of the heating wire and the power supply terminal due to external force can be prevented, and the durability of the heating wire and its joint with the power supply terminal can be improved.

[Brief description of the drawings]

1 is an explanatory view of an embodiment of a heat treatment apparatus according to the present invention, FIGS. 2 and 3 are partial explanatory views of FIG. 1, FIG. 4 is an external view of FIG. 1, and FIG. FIG. 6 is an explanatory view of a power supply terminal section, FIG. 6 is an explanatory view of a heating wire of FIG. 4, FIG. 7 is an explanatory view of installation of FIG.
FIG. 8 is an explanatory diagram of the soaking characteristic in FIG. 1, FIGS. 9 and 10 are explanatory diagrams of the soaking characteristic when the winding interval of the heating wire is not changed, and FIG.
FIG. 12, FIG. 12, and FIG. 13 are explanatory views of another embodiment of the heat generating portion of FIG. DESCRIPTION OF SYMBOLS 1 ... Heating wire, 3 ... Heat-resistant and heat-insulating member 6 ... Inner cover, 7 ... Cooling unit 9 ... Outer cover, 10 ... Power supply terminal 17 ... Face plate, 24 ... Upper ring 27 ... Process tube, 28 ... Wafer

Claims (2)

(57) [Claims] 1. A heat treatment apparatus comprising: a heating section provided with a coil-shaped heating wire on an inner wall of a cylindrical heat-resistant heat insulating member around a cylindrical reaction tube for accommodating an object to be processed; A groove for holding the heating wire is provided on the inner wall of the heating wire, the heating wire is constituted by at least three zones, and the heating wire is provided in the groove with a winding pitch in a temperature reduction zone denser than other zones. An inner cover made of a good heat conductive member is provided on the outer periphery of the heat-insulating member, and an outer cover is provided on the outer periphery of the inner cover via a cooling unit. A heat treatment apparatus comprising a metal face plate joined to the heat treatment apparatus. 2. A heat treatment apparatus according to claim 1, wherein a power supply terminal portion is fixed to said outer cover via an insulating member, and said heat generating wire is electrically connected to said power supply terminal portion. .