JPH05267309A - Heating apparatus - Google Patents

Abstract

PURPOSE:To keep the uniform heating property of a semiconductor material when the semiconductor material such as a semiconductor wafer or the like is heated, to make the strength of an arm for semiconductor-material support use sufficiently large and to efficiently conduct the heat of a ceramic heater to the semiconductor material. CONSTITUTION:The peripheral edge of a semiconductor wafer W is supported by an arm part 12b at a wafer support utensil 12 which can be moved up and down and which is made of a heat-insulating material. A resistance heating element 2 is buried and installed at the inside of a disk-shaped base body 1 which is composed of a dense ceramic. A stepped part 1b which is recessed more than a heating face 1a is formed on the surface side of the disk-shaped base body 1. When the semiconductor wafer W is fixed onto the heating face 1a, one part of the tip of the arm part 12b is housed at the stepped part 1b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device for a plate semiconductor material such as a semiconductor wafer.

[0002]

2. Description of the Related Art Corrosive gases such as chlorine gas and fluorine gas are used as a corrosive gas, an etching gas, and a cleaning gas in a semiconductor manufacturing apparatus requiring a super clean state. Therefore, as a heating device for heating the wafer in contact with these corrosive gases, the surface of the resistance heating element is made of stainless steel,
When a conventional heater coated with a metal such as Inconel is used, exposure to these gases produces undesired particles such as chlorides, oxides and fluorides having a particle size of several μm. Also, a so-called indirect heating type semiconductor wafer heating device has been developed. However, this type has a larger heat loss than the direct heating type, it takes time to raise the temperature, and CV to the infrared transmission window
The attachment of the D film gradually hinders the transmission of infrared rays, and there is a problem that the infrared transmission window absorbs heat and overheats the window.

[0003]

SUMMARY OF THE INVENTION In order to solve the above problems, the present inventors have developed a heating device in which a resistance heating element is embedded in a disc-shaped dense ceramic, and the ceramic heater is held by a graphite case. Was examined. As a result, it was found that this heating device was an extremely excellent device that eliminated the above-mentioned problems.

However, when the semiconductor wafer is heated while being held, a problem occurs in the method of supporting the semiconductor wafer.
That is, in a semiconductor wafer, soaking property is particularly important, and it is necessary to prevent contamination from occurring. Therefore, the semiconductor wafer support that comes into contact with the wafer needs to be made of a heat insulating material such as quartz. However, on the other hand,
Since inorganic heat insulating materials such as quartz have low strength and are brittle, it is necessary to make the semiconductor wafer support thick (for example, to about 5 mm) in order to obtain a predetermined strength. Then, when the semiconductor wafer is placed on the arm portion of the support and the arm portion is fixed on the wafer heating surface, the gap between the wafer heating surface and the semiconductor wafer becomes large and it becomes difficult for heat to be transferred. In particular, under medium-high vacuum conditions, there was no heat conduction due to convection, so the semiconductor wafer could not be heated well.

An object of the present invention is to maintain the uniform heat distribution of the semiconductor material, sufficiently increase the strength of the semiconductor material support, and efficiently transfer the heat of the ceramic heater to the semiconductor material when heating the semiconductor material such as a semiconductor wafer. It is to convey it in a positive way.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a semiconductor material supporting member made of a heat insulating material and provided with arms for supporting the semiconductor material and capable of operating in a relatively opposite direction, and a disc-shaped substrate made of dense ceramics. And a ceramic heater in which a resistance heating element is embedded inside and a stepped portion that is recessed from the heating surface is formed on the surface side of the plate-shaped substrate, the semiconductor material being the heating surface. The present invention relates to a heating device configured such that a part of the arm portion can be accommodated in the step portion over the heating surface when being fixed to the.

[0007]

1 is a schematic sectional view showing a state in which a heating device according to an embodiment of the present invention is attached to a flange portion 14, and FIG. 2 is a partially enlarged sectional view of FIG. FIG. 3 is a plan view in which only main members of the heating device of FIG. 1 are extracted. The substantially disk-shaped ceramic heater 23 is a substantially disk-shaped base 1
And the resistance heating element 2 embedded inside the disk-shaped substrate 1. The disk-shaped substrate 1 is made of dense and gas-tight ceramics. The resistance heating element 2 is embedded in a spiral shape, for example, and both ends of the resistance heating element 2 are connected to the terminals 3, respectively. The surface of each terminal 3 is exposed on the rear surface 1c side of the base 1.

The wafer heating surface 1a of the disk-shaped substrate 1 is, for example, circular, and an annular step portion 1b surrounds the wafer heating surface 1a.
Is formed, and the step portion 1d is formed in a concentric ring shape and surrounds the step portion 1b.
Are formed.

The flat plate-shaped flange portion 14 is to be attached to a semiconductor manufacturing apparatus (not shown). In this example, through holes 14a for leads are formed at two positions, and
The lead member 13 is inserted through 14a. An insulator 15 is installed so as to cover each through hole 14a, and the insulator 15 and the flange portion 14 are sealed with an O ring. An annular metal body 16 is installed below the insulator 15,
It is connected to the lead member 13. A power supply cable is connected to a lower end (not shown) of the lead member 13, and a lead wire 8 is connected to an upper end 13a. A cooling jacket 18 is installed on the flange portion 14.

The heat insulator 9 is integrally formed of a heat insulating material such as quartz. A disk-shaped portion 9a is provided substantially parallel to the heater so as to face the back surface 1c, an annular support flange 9c is formed on the upper peripheral edge of the disk-shaped portion 9a, and the rear surface of the peripheral edge of the ceramic heater 1 is supported. There is. For example, the disc-shaped portion 9a has 2
A through hole 9b is provided at each position, and the lead member 7 is provided in each through hole 9b.
Is inserted. The lead wire 8 is attached to the lower end portion 7a of each lead member 7.
Are connected. Male screws 7b project from the upper end surface of the lead member 7, respectively.

The metal fitting 5 is made of heat-resistant metal. Head of metal fitting 5
A bolt fixing hole 5b is formed in 5a. Bolt fixing hole 5b
And the female screw 3a of the terminal 3 are aligned with each other, the bolt 4 is inserted into the bolt fixing hole 5b, and fitted into the female screw 3a. From the head portion 5a of the metal fitting 5, a pair of elongated locking portions 5c is extended substantially horizontally with the back surface 1c. The male screw 7b is inserted between the pair of locking portions 5c, and the nut 6 is fitted and fixed to the male screw 7b. When the heater is operating, electric power is supplied to the resistance heating element 2 through the lead member 13, the lead wire 8, the lead member 7, the metal fitting 5, and the terminal 3.

At the periphery of the lower side surface of the disk-shaped portion 9a, the cylindrical portion 9d
Is extended. A regulation plate 22 is provided on the upper wall surface of the flange portion 14 so as to project, and the regulation plate 22 abuts against the outer periphery of the lower portion of the cylindrical portion 9d to regulate it, so that the heat insulating body 9 is not displaced laterally. A supporting leg 9e is projectingly provided on a lower end surface of the cylindrical portion 9d, and a tip of the supporting leg 9e is inserted into a blind hole 14b of the flange portion 14.
The spring coil 20 is installed so as to surround the side peripheral surface of the support leg 9e, the lower end of the spring coil 20 contacts the flange portion 14, and the upper end thereof contacts the lower end surface of the cylindrical portion 9d.

The tubular body 10 is made of a refractory metal. Cylindrical body 10
The main body 10a has a cylindrical shape, and the main body 10a surrounds the side peripheral surface of the support portion 9 and a part of the side peripheral surface of the disk-shaped base 1.
An annular mounting portion 10b is formed on the outer periphery of the lower end of the main body 10a, the mounting portion 10b abuts the flange portion 14, and an O-ring seals between them. An annular projecting portion 10c is formed on the inner periphery of the upper end of the main body 10a, the annular projecting portion 10c and the stepped portion 1d face each other, and an annular seal member 21 is sandwiched therebetween. The side heat insulating material 11 includes a main body 11a having an annular shape in plan view, and an extending portion 11b formed on the inner circumference of the upper end of the main body 11a.
Consists of. The main body 11a covers the upper end of the outer peripheral surface of the main body 10a, and the extending portion 11b covers a part of the upper side surface of the annular projecting portion 10c.

The wafer support 12 is made of a heat insulating material and can be moved up and down by a driving device (not shown). The main body 12a of the wafer support 12 has a wide cylindrical shape and surrounds the tubular body 10 and the side insulating material 11. As shown in FIG. 3, a ring-shaped arm portion 12b is formed on the inner circumference of the upper end of the main body 12a. However, in FIG. 3, the wafer support, the semiconductor wafer W, and the ceramic heater are shown in a plan view.
An annular protrusion 12c is formed at the inner end of the arm 12b, and an inclined wafer support surface 12d is formed in an annular shape inside the protrusion 12c.

The wafer supporting surface 12d is formed substantially horizontally over the entire circumference as a whole.
The semiconductor wafer W is placed on. At this stage, the wafer support 12 is raised. Then the wafer support
12 is lowered to bring the tip of the arm 12b close to the step 1b. The step portion 1b is recessed from the wafer heating surface 1a,
The lower side surface of the arm portion 12b is located below the wafer heating surface 1a. The diameter of the semiconductor wafer W is slightly larger than the diameter of the wafer heating surface 1a.

According to the heating apparatus of this embodiment, it is possible to solve the problems such as the contamination in the case of the conventional metal heater and the deterioration of the thermal efficiency in the case of the indirect heating method. Further, the effects obtained by the present invention will be described with reference to the schematic diagrams of FIGS. FIG. 4 schematically shows the main part of the heating device of this embodiment. In the ceramic heater 23, heat escapes by heat conduction, heat radiation, and heat convection from the side peripheral surface, so that the surface temperature at the side peripheral portion becomes lower than the surface temperature at the central portion. In addition, when sintered by hot pressing, etc., the resistance heating element is
A certain distance must be provided between the outermost periphery of 2 and the side peripheral surface of the disk-shaped substrate 1, and the amount of heat generation is inevitably small near the side peripheral surface of the disk-shaped substrate 1. For these reasons, the ceramic heater 23 shown in FIG.
It is possible to secure the soaking property only in the range indicated by.

Given that the size of the semiconductor wafer W is constant,
A heating device as shown in FIG. 5 is also conceivable. In the ceramic heater 23A according to this comparative example, the resistance heating element 2 is embedded inside the disk-shaped substrate 1A, and the arm portion 12b is installed outside the side peripheral surface of the disk-shaped substrate 1A. The outer peripheral edge of the semiconductor wafer W slightly protrudes from the wafer heating surface 1a. In such a ceramic heater 23A, the uniform heating property of the wafer heating surface 1a can be ensured only within the range indicated by the arrow A. This range is inevitably smaller than the size of the semiconductor wafer W, and the area of the semiconductor wafer W that can be effectively heated is small.

In the heating device as shown in FIG. 6, the arm 12b is fixed to the upper side of the wafer heating surface 1a. The radial dimension of the disc-shaped substrate 1B is set to be approximately the same as that in FIG. In this case, a soaking property similar to that of the ceramic heater 23 shown in FIG. 4 can be obtained. However, since the arm portion 12b is sandwiched between the semiconductor wafer W and the ceramic heater 23B, the distance between the semiconductor wafer W and the wafer heating surface 1a is large,
It is impossible to efficiently heat the semiconductor wafer W. It is conceivable to make the arm portion 12b thin and bring the semiconductor wafer W and the wafer heating surface 1a close to each other, but if the arm portion 12b made of an inorganic heat insulating material is made thin, sufficient strength cannot be obtained. When the arm portion 12b is made of a heat-resistant metal, heat is conducted from the side peripheral surface of the semiconductor wafer W to the arm portion 12b, so that the semiconductor wafer W cannot maintain heat uniformity.

As described above, by adopting the configuration as schematically shown in FIG. 4, it is possible to maintain the temperature uniformity of the semiconductor wafer W and prevent the temperature of the side peripheral portion from lowering, so that the strength of the arm portion 12 is improved. It can be kept sufficiently high, and the heat of the ceramic heater can be efficiently transferred to the semiconductor wafer W.

Further, in the embodiment, the annular projecting portion 10c of the tubular body 10 is urged against the step portion 1d via the annular seal member 21. This biasing force is given by the coil spring 20. Thereby, the inner space 19 of the tubular body 10
And the space in which the semiconductor wafer W is installed can be sealed, and the inner space 19 can be filled with an inert gas such as nitrogen gas or argon gas. Therefore, it is possible to prevent the metallic members such as the lead members 13 and 7 and the terminals 3 from being corroded by the corrosive gas in the semiconductor manufacturing apparatus. Further, it is possible to prevent the conductive film from being formed on the back surface 1c by the CVD gas or the like in the apparatus.

Further, in the process such as low pressure CVD, since the inside of the apparatus is degassed to be in a high vacuum state, a considerable pressure is applied to the cylindrical body 10. However, the tubular body 10 is made of a heat-resistant metal and can sufficiently withstand the pressure of the inert gas in the inner space 19.
However, when the tubular body 10 is made of a heat-resistant metal, when the ceramics heater 23 is heated, the tubular body 10 extends in the vertical direction and the annular projection 10c tends to separate from the step 1d.
However, in this example, the heat insulator 9 rises following this,
Since the rise of the annular projecting portion 10c is absorbed, the sealed state is maintained even at high temperature.

When the annular seal member 21 is made of soft metal, the airtightness can be maximized. As such a soft metal, platinum having the high corrosion resistance and high melting point is most preferable. In addition, nickel, silver and gold are preferable in terms of corrosion resistance.

As the material of the disc-shaped substrate 1, silicon nitride, sialon, aluminum nitride and the like are preferable, and silicon nitride and sialon are more preferable in terms of thermal shock resistance. Aluminum nitride is most preferable in terms of corrosion resistance against halogen-based corrosive gas.
The material of the resistance heating element 2 is preferably tungsten, molybdenum, platinum or the like. As the heat insulating material constituting the heat insulating body 9, the side heat insulating material 11, and the wafer support 12, quartz, crystal,
Silicon oxide glass or the like is preferable. As the heat-resistant metal forming the tubular body 10, Inconel, nickel, hastelloy,
Stainless steel or the like is preferable.

FIG. 7 is a schematic plan view showing a heating device according to another embodiment of the present invention. The overall structure of the substantially disk-shaped ceramics heater 23C is almost the same as that of the ceramics heater 23. However, the shape of the disk-shaped base 31 on the surface side is slightly different. That is, an annular step portion 31d is provided on the peripheral edge of the surface of the disk-shaped substrate 31, and inside the step portion 31d,
A flat wafer heating surface 31a is formed. The wafer heating surface 31a has a circular plane shape as a whole, but planar rectangular step portions 31b are formed at, for example, three positions.

On the other hand, in this example, three arms 32 each having a substantially rectangular plane are used. A wafer support surface 32a is provided as an inclined surface at the tip of each arm 32. The semiconductor wafer W is placed on the wafer support surface 32a of each arm 32,
The tip end of 32 is housed in the step 31b, and the semiconductor wafer W is fixed on the wafer heating surface 31a.

In each of the above-mentioned examples, the wafer heating surface is directed upward. However, the present invention can be applied to the case where the wafer heating surface is faced downward, the semiconductor wafer is supported by the arms of the wafer support, and the semiconductor wafer is fixed below the wafer heating surface. In each of the above examples, the arm is stopped with a slight gap provided between the semiconductor wafer W and the wafer heating surface 1A. However, the size of the recesses of the stepped portions 1b and 31b is made slightly larger, the arm portions 12b and 32 are further lowered, the semiconductor wafer W is placed directly on the wafer heating surface 1a, and the support of the semiconductor wafer by the arm portions is released. Good.

[0027]

As described above, according to the present invention, since the semiconductor material support for supporting the semiconductor material is made of a heat insulating material, heat conduction from the periphery of the semiconductor material to the semiconductor material support is small. .. Further, when fixing the semiconductor material on the heating surface of the ceramic heater, a part of the arm portion can be accommodated in the step portion over the heating surface, so that sufficient strength can be given to the arm portion of the semiconductor material support. Even if the arm portion is thick, the distance between the semiconductor material and the heating surface does not become large. Therefore, the heat of the ceramic heater can be efficiently transferred to the semiconductor material.

Moreover, a stepped portion which is recessed from the heating surface is formed on the surface side of the board-like substrate, and a part of the arm portion can be accommodated in this stepped portion. Then, the peripheral edge of the semiconductor material is supported by the arm portion. Therefore, the planar size of the disk-shaped substrate is larger than the planar size of the semiconductor material. As a result, for the reasons described above, it is easy to equalize the temperature of the semiconductor material installation region.

[Brief description of drawings]

FIG. 1 shows a heating device according to an embodiment of the present invention in which a flange portion 14 is provided.
It is a schematic sectional drawing which shows the state attached to.

FIG. 2 is an enlarged sectional view of a main part of the heating device of FIG.

FIG. 3 is a plan view showing main members of the heating device of FIG.

FIG. 4 is a cross-sectional view schematically showing main members of the heating device of FIG.

FIG. 5 is a cross-sectional view schematically showing a heating device of a comparative example.

FIG. 6 is a cross-sectional view schematically showing a heating device of a comparative example.

FIG. 7 is a plan view showing a main part of a heating device according to another embodiment.

[Explanation of symbols]

 1, 1A, 1B, 31 Disk-shaped substrate 1a, 31a Wafer heating surface 1b, 1d, 31b, 31d Step portion 1c Rear surface 2 Resistance heating element 3 Terminal 9 Heat insulator 12 Wafer support 12a Main body 12b, 32 Arm 12d, 32a Wafer support surface 23, 23A, 32B, 23C Ceramics heater W Semiconductor wafer

Claims (1)

[Claims] 1. A semiconductor material supporting member made of a heat insulating material and provided with an arm portion for supporting a semiconductor material and capable of operating in a relatively opposite direction, and a resistance heating element embedded in a board-shaped substrate made of dense ceramics. And a ceramics heater in which a stepped portion that is recessed from the heating surface is formed on the surface side of the plate-shaped substrate, wherein the arm is provided when fixing the semiconductor material to the heating surface. A part of the portion can be accommodated in the step portion over the heating surface,
Heating device.