JP2005294606A - Wafer heating unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain a temperature distribution mainly in the circumferential direction appearing on a wafer heated surface, in a wafer heating unit. <P>SOLUTION: A wafer heating unit 16 comprises a plate-like body 13 with a wafer heated surface 13a and a rear 13b, and a heater 6 installed at the rear 13b of the plate-like body 13. This plate-like body 13 can rotate relatively with respect to the heater 6. It is recommended that the plate-like body 13 can rotate with the central shaft D of the heater 6 as a center, and a clearance 14 is formed between the plate-like body 13 and the heater 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wafer heating apparatus.

In a semiconductor manufacturing apparatus, a ceramic heater for heating a wafer is employed in manufacturing a semiconductor thin film from a source gas such as silane gas by thermal CVD or the like. In such a heater, it is necessary to prevent semiconductor defects by ensuring the uniformity of the temperature of the heating surface while maintaining the heating surface at a high temperature. However, the ceramic heater has a heating element embedded in the ceramic substrate, and a certain degree of temperature variation occurs on the heating surface.
Patent Documents 1 and 2 disclose techniques for increasing the temperature uniformity of the wafer heating surface of a ceramic heater.
JP-A-6-53145 JP 2002-50657 A

For example, a ceramic heater 11 as shown in FIGS. 1 and 2 will be described. The heater 11 includes a disk-shaped ceramic base 2, a resistance heating element 4 embedded in the base 2, and a terminal 5 that supplies power to the heating body 4. A wafer is placed on the heating surface 2 a of the base 2. 2b is a back surface from which the terminal 5 is exposed, and 2c is a side surface. On the heating surface 2a, a hot spot or a cold spot C extending in the circumferential direction may be generated in a part of the heater due to a displacement of the heating element 4 in the embedded state.
When there is a temperature gradient in the radial direction on the heater heating surface 2a, a radiant energy from the side surface 2c is changed by installing a ring on the heater or surrounding the heater with the ring, thereby changing the temperature in the radial direction. The distribution can be controlled to be small. However, reducing the temperature distribution in the circumferential direction as shown in FIG. 2 is difficult in design by such a method.

  An object of the present invention is to suppress a temperature distribution mainly in the circumferential direction that appears on a wafer heating surface in a wafer heating apparatus.

  The present invention includes a plate-like body having a wafer heating surface and a back surface, and a heater provided on the back side of the plate-like body, and the plate-like body is rotatable relative to the heater. The present invention relates to a wafer heating apparatus.

  Even if the temperature distribution occurs in the circumferential direction on the heating surface of the heater due to the displacement of the heating element in the heater, a separate plate is installed on the heater, and the plate is used as the heater. It can be relatively rotated. Thereby, even if the temperature distribution is generated on the heater surface, the circumferential temperature distribution on the plate-like body surface is suppressed by the rotation of the plate-like body in the circumferential direction on the heater surface.

  For example, the plate-like body 13 is combined with the heater 6 as shown in FIG. 3 to constitute the heating device 16 shown in FIG. The heater 6 of this example is provided on a disk-shaped base body 7, a resistance heating element 8 embedded in the base body 7, a terminal 5 for supplying power to the resistance heating body 8, and a back surface 7 b side of the base body 7. A tubular attachment 10 is provided. A terminal 5 is fixed and protected in the inner space 12 of the mounting portion 10.

  Here, it is assumed that a cold spot C extending in the circumferential direction is generated on the heating surface 7a side of the base 7 as shown in FIG. 5, for example. Such a cold spot C is generated by, for example, a deviation in the embedding interval of the heating element 8 when viewed in the radial direction of the heating surface. Such a cold spot C in the circumferential direction cannot be erased by controlling the heat radiation from the side surface 7c of the base body 7, unlike the temperature distribution in the radial direction.

  Here, in this invention, as shown in FIG. 4, the plate-shaped body 13 is installed on the base | substrate 7. As shown in FIG. The back surface 13b of the plate-like body 13 faces the heating surface 7a of the base body 7, and a gap 14 is formed between the back surface 13b and the heating surface 7a. A wafer W is placed on the heating surface 13a of the plate-like body 13 directly or at a predetermined interval and heated. The plate-like body 13 is rotatable about the central axis D of the heater 6. In this example, the rotating shaft 15 is attached to the back surface 13 b side of the plate-like body 13. The rotating shaft 15 is inserted into the central through hole 7c of the base body 7, and further inserted into the inner space 12 of the mounting portion 10, and is connected to a rotating mechanism (not shown).

  As a result, for example, as shown in FIG. 5, even when a cold spot C is generated on the heating surface 7a of the base body 7, the plate-like body 13 is rotated around the axis D as shown by an arrow A as shown in FIG. When moved, an excessive amount of heat is distributed on the cold spot C. As a result, a cold spot in the rotation direction A on the heating surface 13 of the plate-like body 13 is suppressed.

  In the present invention, the form of the heater is not particularly limited. For example, the heater may be a disk-shaped body made of a conductor, or may be a heater in which a resistance heating element is embedded in a disk-shaped body made of an insulator. Examples of the conductor include nickel, nickel alloy, stainless steel, aluminum, and aluminum alloy. Ceramics are particularly preferable as the insulator. The ceramic may preferably be a known ceramic material such as a nitride ceramic such as aluminum nitride, silicon carbide, silicon nitride, boron nitride and sialon, or an alumina-silicon carbide composite material. In order to impart high corrosion resistance to corrosive gases such as halogen-based gases, aluminum nitride and alumina are particularly preferable. Moreover, what is called a sheath heater may be used.

  The shape of the substrate 7 is not particularly limited, but a disk shape is preferable. The heating surface 7a may have a pocket shape, an embossed shape, or a groove shape. Although the manufacturing method of the base | substrate 7 is not limited, The hot press manufacturing method and the hot isostatic press manufacturing method are preferable. The shape of the heating element 8 may be a coil shape, a ribbon shape, a mesh shape, a plate shape, or a film shape.

The form of the plate-like body 13 is not particularly limited. The material of the plate-like body 13 may be an insulator such as ceramic or glass. The ceramic may preferably be a known ceramic material such as nitride ceramics such as aluminum nitride, silicon carbide, silicon nitride, boron nitride and sialon, and alumina-silicon carbide composite material.
The thickness of the plate-like body 13 is not particularly limited. The thickness of the plate-like body 13 is preferably 0.5 mm or more in order to reduce the temperature distribution on the heating surface of the heater 6. From this viewpoint, it is more preferable that the thickness of the plate-like body 13 is 1 mm or more. On the other hand, if the thickness of the plate-like body 13 is too large, the thermal efficiency is lowered, and the temperature control on the heating surface 13a of the plate-like body 13 becomes difficult. From this viewpoint, the thickness of the plate-like body 13 is preferably 10 mm or less, and more preferably 5 mm or less.

  The plate-like body 13 and the heater 6 can be brought into contact with each other, but a slight gap 14 can also be provided. In the case of providing the gap 14, from the viewpoint of reducing friction and contact during rotation, the gap 14 is preferably 0.05 mm or more, and more preferably 0.1 mm or more. Further, the heat conduction from the heater 6 to the plate-like body 13 can be promoted by flowing the backside gas through the gap 14.

  In the present invention, the heater 6 and the plate-like body 13 are relatively rotated. At this time, the heater 6 can be fixed and the plate-like body 13 can be rotated. Further, the plate-like body 13 can be fixed and the heater 6 can be rotated. Furthermore, both the heater 6 and the plate-like body 13 can be rotated. A rotation mechanism such as the plate-like body 13 is not particularly limited, and a normal motor device can be used.

  The heating apparatus of the present invention can be suitably applied to semiconductor manufacturing apparatuses in general. Here, the semiconductor manufacturing apparatus means an apparatus used in a wide range of semiconductor manufacturing processes. This includes an etching apparatus, a baking apparatus, a curing apparatus, a cleaning apparatus, and an inspection apparatus in addition to the film forming apparatus.

  In a preferred embodiment, a hole for inserting a wafer support lift pin is formed in the plate-like body and the heater. In this case, when the plate-shaped body is stationary with respect to the heater, the hole of the plate-shaped body and the hole of the heater are communicated with each other, whereby the lift pin is connected to the hole of the plate-shaped body and the hole of the heater. It is preferable to allow insertion. For example, in the example shown in FIG. 7, the plate-like body 13 is provided with a lift pin insertion hole 20 </ b> B, and the heater 6 is provided with a lift pin insertion hole 20 </ b> A. When the rotation of the plate-like body 13 is stopped, the plate-like body 13 is positioned so that the hole 20B is positioned above the hole 20A and both form an integral through hole.

  In a preferred embodiment, a clearance is provided between the wafer and the plate-like body. Thus, heat transfer from the plate-like body to the wafer can be controlled, and the temperature distribution of the wafer can be controlled. For example, in the example of FIG. 8, the concave portion 22 is formed on the surface 13 a side of the plate-like body 13 </ b> A, whereby a clearance is formed between the plate-like body 13 and the wafer W. By changing the size of this clearance, the heat transfer from the plate-like body 13A to the wafer can be changed, and the temperature distribution of the wafer W can be changed. For example, the clearance between the plate-like body 13 </ b> A and the wafer W can be increased at the central portion of the wafer W and decreased at the peripheral portion of the wafer W.

Comparative example

  The heater 6 shown in FIG. 3 was manufactured. Here, the material of the substrate 7 was an aluminum nitride sintered body, the diameter of the substrate 7 was 350 mm, and the thickness was 10 mm. Inside the base body 7, a molybdenum coil spring-shaped heating element 8 was embedded. The power supply member 5 is made of nickel.

  The heater 6 was heated so that the set temperature of the heating surface 7a was about 500 ° C. This set temperature was confirmed by a thermocouple. And the temperature distribution of the heating surface 7a was observed with the infrared radiation thermometer. As a result, a relatively low temperature (490 ° C. or lower) region C was generated.

  A plate-like body 13 was installed on the heater 6 of the comparative example. The material of the plate-like body 13 was an aluminum nitride sintered body, the diameter of the plate-like body 13 was 350 mm, and the thickness was 3 mm. The gap 14 between the plate-like body 13 and the substrate 7 was 0.5 mm. The temperature of the heating device was raised so that the set temperature of the heating surface 13a was about 450 ° C. The plate-like body 13 was rotated at a speed of 10 to 20 rpm, and the temperature distribution on the heating surface 13a was observed with an infrared radiation thermometer. The cold spot 13 extending in the circumferential direction was not observed on the heating surface 13a, and the temperature difference was 2 ° C.

2 is a cross-sectional view schematically showing a ceramic heater 11. FIG. 3 is a plan view showing a heating surface 2a of the ceramic heater 11. FIG. It is sectional drawing which shows the heater 6 typically. It is sectional drawing which shows typically the heating apparatus 16 provided with the heater 6 and the plate-shaped body 13. As shown in FIG. 3 is a plan view showing a heating surface 7a of the heater 6. FIG. 4 is a plan view showing a heating surface 13a of the plate-like body 13. FIG. It is sectional drawing which shows the example which provided the holes 20B and 20A in the plate-shaped body 13 and the heater 6. FIG. 4 is a cross-sectional view showing an example in which a clearance 22 is provided between a plate-like body 13A and a wafer W. FIG.

Explanation of symbols

  6 Heater 7 Substrate 7a Heating surface of heater 6 8 Heating element 13, 13A Plate-like body 13a Heating surface of plate-like body 13b Back face of plate-like body 14 Gap between plate-like body 13 and base body 16 Heating device A times Dynamic D Heater central axis W Wafer

Claims (5)

  A plate-like body having a wafer heating surface and a back surface, and a heater provided on the back side of the plate-like body, the plate-like body being rotatable relative to the heater A wafer heating device.   The heating apparatus according to claim 1, wherein the plate-like body is rotatable about a central axis of the heater.   The heating apparatus according to claim 1, wherein a gap is provided between the plate-like body and the heater.   The heating apparatus according to any one of claims 1 to 3, wherein a hole for inserting a lift pin that supports the wafer is formed in the plate-like body and the heater.   The heating apparatus according to any one of claims 1 to 4, wherein a clearance is provided between the wafer and the plate-like body.

Images