JP2009123577A - Substrate heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate heating device for keeping the temperature of a substrate uniform both when the temperature of the substrate rises and when the temperature of the substrate is stabilized. <P>SOLUTION: The substrate heating device includes a plate-like base material, and a belt-like resistance heating element formed along the under face of the plate-like base material to generate heat with energization. A cross section S1 of the belt-like resistance heating element at its part facing the center of the plate-like base material is larger than a cross section S2 of the belt-like resistance heating element at its part facing the periphery of the plate-like base material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a substrate heating apparatus that heats a plate-like substrate, for example, a semiconductor wafer, a printed board, a glass substrate, and the like, and more particularly to a substrate heating apparatus that can uniformly heat the substrate.

For example, in the manufacture of a semiconductor wafer, there are many processes that require heat treatment, such as a CVD film forming process, an epitaxial film forming process, an oxide film forming process, and a diffusion film forming process. As typical examples of a substrate heating apparatus for heating a plate-like substrate such as a semiconductor wafer, those disclosed in Patent Documents 1 and 2 below can be given. These substrate heating devices include a plate-like base material and a strip-like resistance heating element that generates heat by energization formed along the lower surface of the plate-like base material. The strip-shaped resistance heating element is formed concentrically or spirally on the lower surface side of the plate-like substrate. The belt-like resistance heating element is formed by baking so as to have a uniform thickness and a uniform width in any part of the plate-like substrate.
JP 2001-313249 A JP 2001-203156 A

  In this type of substrate heating apparatus, the temperature uniformity needs to be maintained when the temperature rises during the process and when the temperature is stable, but the heat transfer when the substrate temperature rises is mainly perpendicular to the substrate. The heat transfer when the substrate temperature is stable occurs mainly parallel to the substrate. Therefore, in order to maintain the temperature uniformity of the substrate temperature both when the substrate temperature rises and when the substrate temperature is stable, the substrate heating device needs to have two or more types of heat generation distribution. However, in the above-described substrate heating apparatus according to the prior art, since the strip-like resistance heating element has a uniform thickness and a uniform width at any part of the plate-like base material, only one heat generation distribution is formed.

  The present invention has been made in view of the above problems, and provides a substrate heating apparatus capable of maintaining temperature uniformity of a substrate both when the substrate temperature rises and when the substrate temperature is stable. The purpose is that.

  In order to achieve the above object, a substrate heating apparatus according to the present invention includes a plate-like base material, and a belt-like resistance heating element that generates heat by energization formed along the lower surface of the plate-like base material. The section S1 of the strip-shaped resistance heating element at the portion facing the center of the material is characterized by being larger than the section S2 of the strip-shaped resistance heating element at the portion facing the peripheral portion of the plate-like substrate.

  According to one embodiment of the present invention, the width W of the belt-like resistance heating element is constant, and the belt-like portion is formed at the portion facing the central portion of the plate-like substrate as compared with the portion facing the peripheral portion of the plate-like substrate. The resistance heating element can be configured to have a large thickness D.

  The thickness at the part facing the peripheral part of the plate-like base material The thickness of the strip-like resistance heating element can be set to half the thickness at the part facing the central part of the plate-like base material. The thickness D of the heating element is configured so that it continuously decreases linearly or in steps from the portion facing the central portion of the plate-like substrate toward the portion facing the peripheral portion of the plate-like substrate. Can be done.

  In the substrate heating apparatus according to the present invention, the belt-like resistance heating element may be formed in a meandering shape over the entire surface along the lower surface of the plate-like base material.

  Furthermore, in the substrate heating apparatus according to the present invention, the plate-like substrate can be made of PBN.

  In the substrate heating apparatus according to the present invention, the cross section S1 of the strip-shaped resistive heating element at the portion facing the center of the plate-like base material is larger than the cross-section S2 of the strip-shaped resistive heating element at the portion facing the peripheral portion of the plate-like base material. By reducing the resistivity of the belt-like resistance heating element in the portion facing the central portion of the plate-like base material compared to the portion facing the peripheral portion of the plate-like base material, The substrate heating apparatus can have two or more heat generation distributions, and the temperature uniformity of the substrate can be maintained both when the substrate temperature is rising and when the substrate temperature is stable.

  In the substrate heating apparatus according to the present invention, the width W of the belt-like resistance heating element is constant, and the belt-like resistance heating element is located at the portion facing the central portion of the plate-like substrate as compared with the portion facing the peripheral portion of the plate-like substrate. When the thickness D of the plate-like substrate is made large, the thickness D of the belt-like resistance heating element is made constant, and the portion facing the central portion of the plate-like substrate is compared with the portion facing the peripheral portion of the plate-like substrate. As compared with the case where the width W of the belt-like resistance heating element is increased, the temperature distribution can be easily adjusted and processed.

  Embodiments of a substrate heating apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 schematically shows a main part of a substrate heating apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a heater housing, and a first heater reflector 2 and a second heater reflector 3 are provided in the heater housing 1. Are arranged concentrically. These two heater reflectors 2 and 3 form a basin shape, and each upper surface is opened. The first heater reflector 2 is supported by being separated from the heater housing 1 by bolts 5 and nuts 6 with an insulating tube 4 interposed between the first heater reflector 2 and the heater housing 1. In the drawing, a set of insulating tubes 4, bolts 5 and nuts 6 are shown, but a plurality of such support means are naturally provided along the periphery of the heater reflector 2. The second heater reflector 3 is supported separately from the first heater reflector 2 by bolts 8 and nuts 9 with an insulating tube 7 interposed between the second heater reflector 3 and the first heater reflector 2. Although only one set of the insulating tube 7, the bolt 8 and the nut 9 is shown in the drawing, a plurality of sets are naturally provided.

  A first heater pressing member 11 is disposed on the second heater reflector 3 via an insulating collar 10, and a second heater pressing member 12 is provided in contact with the first heater pressing member 11. ing. The first heater reflector 2, the second heater reflector 3, and the first heater pressing member 11 are assembled to each other by bolts 8 and nuts 9 at a predetermined interval as shown in the figure. In the illustrated embodiment, the first heater holding member 11 is made of molybdenum, and the second heater holding member 12 is made of pyrolytic boron nitride (PBN) having excellent heat resistance, thermal conductivity, and corrosion resistance. .

  On the second heater pressing member 12, a strip-like resistance heating element 14 that generates heat by energization is formed along the lower surface of the plate-like substrate 13 that forms a soaking plate. The plate-like substrate 13 is made of pyrolytic boron nitride (PBN) having excellent heat resistance, thermal conductivity, and corrosion resistance, like the second heater pressing member 12. A substrate (not shown) to be heated is mounted on the upper surface of the plate-like base material 13. The strip-like resistance heating element 14 has a width W and is uniform over its entire length. Both ends of the strip-like resistance heating element 14 are connected to an external power source (not shown) via lead wires extending in the insulating tube 15.

  2 to 4 show an embodiment of a strip-like resistance heating element. As shown in the plan view of FIG. 2, the band-shaped resistance heating element 20 having a width W is substantially half the width W of the band-shaped resistance heating element 20 over the entire area of the lower surface of the disk-shaped plate-like substrate (see FIG. 1). Are arranged in a meandering shape at intervals of. The cross-sectional area S1 of the portion of the belt-like resistance heating element 20 located at the center of the plate-like substrate indicated by a circle 21 is a break of the portion of the belt-like resistance heating element 20 located at the periphery of the plate-like substrate outside the circle 21. The thickness D1 of the portion of the belt-like resistance heating element 20 located at the center of the plate-like substrate indicated by the circle 21 so as to be larger than the area S2 is a belt-like shape located at the periphery of the plate-like substrate outside the circle 21. The resistance heating element 20 is formed approximately twice as thick as the thickness D2. With this configuration, the resistivity in the portion of the belt-like resistance heating element 20 facing the central portion of the plate-like base material is smaller than the portion of the belt-like resistance heating element 20 facing the peripheral portion of the plate-like base material, As a result, the amount of heat generated during energization of the belt-like resistance heating element 20 is reduced at the site of the belt-like resistance heating element 20 located at the center of the plate-like substrate, and 2 is applied to the substrate heating apparatus at the central part and the peripheral part. The above-described heat generation distribution can be obtained, and the temperature distribution in the substrate can be maintained uniformly throughout both the case where the substrate temperature rises and the case where the substrate temperature is stable.

  5 to 7 show another embodiment of the strip-like resistance heating element. As shown in the plan view of FIG. 5, the strip-shaped resistance heating element 30 having a width W is substantially half the width W of the strip-shaped resistance heating element 30 over the entire area of the lower surface of the disk-shaped plate-like substrate (see FIG. 1). Are arranged in a meandering shape at intervals of. In this case, the thickness of the strip-like resistance heating element 30 decreases linearly from the portion corresponding to the central portion of the plate-like substrate toward the portion corresponding to the peripheral portion of the plate-like substrate, The thickness D1 of the portion of the belt-like resistance heating element 30 located in the central portion is formed approximately twice the thickness D2 of the portion of the belt-like resistance heating element 30 located in the peripheral portion of the plate-like base material. Thereby, the cross-sectional area of the strip-shaped resistance heating element 30 is changed from the cross-sectional area S1 of the portion of the strip-shaped resistance heating element 30 located at the center of the plate-shaped substrate to the strip-shaped resistance heating element 30 positioned at the peripheral portion of the plate-shaped substrate. It gradually decreases outward until the cross-sectional area S2 of this part.

  By comprising in this way, like the case of embodiment shown in FIGS. 5-7, compared with the site | part of the strip | belt-shaped resistance heating element 30 facing the peripheral part of a plate-shaped base material, it is the said plate-shaped base material. The resistivity at the portion of the belt-like resistance heating element 30 facing the center portion is reduced, and as a result, the amount of heat generated when the belt-like resistance heating body 30 is energized gradually decreases from the peripheral portion to the center portion of the plate-like substrate. In addition, the substrate heating device can have two or more types of heat distribution at the central part and the peripheral part, and the temperature uniformity of the substrate is maintained both when the substrate temperature is rising and when the substrate temperature is stable. can do.

  As described above, in the present invention, the strip-like resistance heating elements 20 and 30 to be used have a constant width and a thickness that decreases toward the peripheral portion. This makes it easy to adjust the temperature distribution. In addition, since the strip-like resistance heating elements 20 and 30 having a certain width are arranged at regular intervals, they are configured with a complicated pattern that is sparse in the central portion and dense in the peripheral portion as in the prior art. This eliminates the need to manufacture the heating element, and thus manufacture the substrate heating apparatus relatively easily.

Examples of the material of the strip-like resistance heating elements 20 and 30 used in the present invention include Ta, Mo, and graphite.

  By the way, in the illustrated embodiment, the heating device is formed in a circular shape, but naturally, it can also be configured in a polygonal shape such as a rectangle or a rectangle in accordance with the shape of the substrate to be heated. Further, the strip-like resistance heating element to be used does not need to have a square cross section as in the illustrated embodiment, and a polygon, an ellipse, or a circle other than a square can be used.

  In the embodiment shown in FIGS. 2 to 4, the thickness of the belt-like resistance heating element may be changed from D1 to D2 with two or more steps from the center to the periphery.

1 is a schematic cross-sectional view showing a main part of a substrate heating apparatus according to an embodiment of the present invention. The schematic plan view which shows one Embodiment of the strip | belt-shaped resistance heating element used for the apparatus of FIG. The schematic sectional drawing in alignment with arrow II-II of the strip | belt-shaped resistance heating element of FIG. FIG. 3 is a schematic cross-sectional view of the belt-like resistance heating element of FIG. 2 along arrows III-III. The schematic plan view which shows another embodiment of the strip | belt-shaped resistance heating element used for the apparatus of FIG. The schematic sectional drawing in alignment with arrow IV-IV of the strip | belt-shaped resistance heating element of FIG. FIG. 6 is a schematic cross-sectional view along the arrow VV of the strip-like resistance heating element in FIG. 5.

Explanation of symbols

1: Heater housing 2: First heater reflector 3: Second heater reflector 4: Insulating tube 5: Bolt 6: Nut 7: Insulating tube 8: Bolt 9: Nut 10: Insulating collar 11: First heater pressing member 12: Second heater pressing member 13: Plate-like base material 14: Strip-like resistance heating element 15: Insulating tube 20: Strip-like resistance heating element 30: Strip-like resistance heating element

Claims (7)

In a substrate heating apparatus comprising a plate-like base material and a belt-like resistance heating element that generates heat by energization formed along the lower surface of the plate-like base material,
The cross-sectional area S1 of the strip-shaped resistive heating element at the portion facing the center of the plate-like base material is larger than the cross-sectional area S2 of the strip-shaped resistive heating element at the portion facing the peripheral portion of the plate-like base material. Substrate heating device.   The width W of the belt-like resistance heating element is constant, and the thickness of the belt-like resistance heating element at the portion facing the center of the plate-like substrate as compared to the portion facing the peripheral portion of the plate-like substrate. 2. The substrate heating apparatus according to claim 1, wherein D is large.   The thickness at the part facing the peripheral part of the plate-like base material The thickness of the strip-like resistance heating element is half the thickness at the part facing the central part of the plate-like base material. The substrate heating apparatus according to 1.   The thickness D of the strip-like resistance heating element continuously changes linearly from a portion facing the central portion of the plate-like substrate toward a portion facing the peripheral portion of the plate-like substrate. The substrate heating apparatus according to claim 2 or claim 3, wherein   The thickness D of the strip-like resistance heating element is changed in a stepped manner from a portion facing the central portion of the plate-like substrate toward a portion facing the peripheral portion of the plate-like substrate. The substrate heating apparatus according to claim 2 or claim 3 to be performed.   3. The substrate heating apparatus according to claim 1, wherein the belt-like resistance heating element is formed in a meandering shape over the entire surface along the lower surface of the plate-like substrate.   The said plate-shaped base material is comprised from PBN, The substrate heating apparatus as described in any one of Claims 1-6 characterized by the above-mentioned.

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