JP2004221563A - Wafer heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems with a wafer heating device that it takes too much time for wafer temperatures to become stable when wafer change is made on a plate type ceramic, and also that the overshoot amount of wafer temperature is too large. <P>SOLUTION: In the wafer heating device where two or more belt-like resistance heaters are formed on the surface or inside the plate type ceramic, recesses are arranged in the corresponding position to each of the resistance heaters of the plate type ceramic, and temperature measurement elements are arranged in the relative recess, the main feature of the wafer heating device is that the power flux density in the neighborhood of the corresponding temperature measurement element of at least one belt-like resistance heater arranged in the outermost periphery of the plate type ceramic is designed to be smaller than the average power flux density of the belt-like resistance heaters. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a ceramic heater mainly used to heat a wafer, for example, to form a semiconductor thin film on a wafer such as a semiconductor wafer or a liquid crystal substrate or a circuit board, or to apply a resist coated on the wafer This is suitable for forming a resist film by drying and baking the solution.

  For example, in a semiconductor thin film forming process, an etching process, a resist film baking process, and the like in a manufacturing process of a semiconductor manufacturing apparatus, a wafer heating device is used to heat a semiconductor wafer (hereinafter, abbreviated as a wafer). I have.

  Conventional semiconductor manufacturing equipment has used a batch type in which a plurality of wafers are formed at a time. However, as the size of wafers increases from 8 inches to 12 inches, it is necessary to improve processing accuracy. In recent years, a technique called a single-wafer processing for processing one sheet at a time has been implemented. However, in the case of the single-wafer method, the number of processes per one time is reduced, and therefore, it is necessary to shorten the processing time of the wafer. For this reason, it has been required for the wafer support member to shorten the heating time of the wafer, speed up the suction and desorption of the wafer, and improve the heating temperature accuracy.

  In forming the resist film on the wafer, one main surface of a plate-shaped ceramic body 32 made of ceramics such as aluminum nitride or silicon carbide is used as shown in FIG. A ceramic heater 31 having a structure in which a resistance heating element 35 and a power supply section 36 are provided on the other main surface via an insulating layer 34 and a conductive terminal 37 is pressed and fixed to the power supply section 36 by an elastic body 38 is used. Had been. The plate-shaped ceramic body 32 is fixed to the support body 41 by bolts 47, and a temperature measuring element 40 is inserted into the plate-shaped ceramic body 32, whereby the temperature of the plate-shaped ceramic body 32 is set to a predetermined temperature. In such a system, the power supplied from the conduction terminal 37 to the resistance heating element 35 is adjusted so as to maintain the temperature. Further, the conduction terminal 37 was fixed to the plate-like structure 43 via an insulating material 39.

  A support pin 44 inserted into the bottomed hole 45 is provided on the mounting surface 33 of the ceramic heater 31, and when the wafer W is mounted on the mounting surface 33, the wafer W is removed from the mounting surface 33. Non-contact is made. After the wafer W coated with the resist solution is placed on the support pins 44, the resistance heating element 35 is heated to heat the wafer W on the placement surface 33 via the plate-shaped ceramic body 32. Then, the resist solution is dried and baked to form a resist film on the wafer W.

  Further, as the ceramic material constituting the plate-shaped ceramic body 32, nitride ceramics or carbide ceramics has been used.

  In the heat treatment of a chemically amplified resist that has been used for miniaturization of semiconductor wiring in recent years, a transient characteristic until the temperature is stabilized when the wafer W is replaced on the plate-shaped ceramic body 31 is obtained. The temperature variation in the surface of the wafer W is extremely important for the chemical amplification treatment of the resist after exposure, and it is necessary to control the temperature more precisely and more responsively than before.

Patent Document 1 discloses a method in which a nitride ceramic is used as the plate-shaped ceramic body 32 and the temperature is controlled while measuring the temperature in the vicinity of the heating element. When power is supplied to the wafer heating device 31, the temperature of the mounting surface 33 of the wafer W starts to rise. However, since the surface temperature of the outer peripheral portion of the mounting surface 33 becomes lower, the heat is removed from the outer peripheral portion. The resistance heating element 35 is designed so that the temperature distribution of the plate-shaped ceramic body 32 becomes uniform with respect to the set temperature in a steady state in consideration of the temperature drop due to the temperature. That is, in consideration of the heat removal from the outer peripheral portion of the mounting surface 33, the resistance of the outer peripheral portion of the resistance heating element 35 is made larger than the resistance of the central portion of the resistance heating element 35, and the temperature of the central portion and the outer peripheral portion is increased. A plate-like ceramic body 32 having a small difference was obtained.
JP 2001-135460 A

  However, when the wafer W is replaced on the plate-shaped ceramic body 32, there is a problem that the amount of overshoot of the temperature in the wafer surface during transition until the temperature is stabilized is large.

  Further, in a wafer heating apparatus that heats a large wafer W of 300 mm or more, when heated to a set temperature, the temperature rise curves at the center and the outer periphery are different, and the temperature in the plane of the wafer W becomes constant. There was a problem that the temperature stabilization time was long.

  In the present invention, paying attention to the temperature behavior of the plate-shaped ceramic, a plurality of belt-shaped resistance heating elements are formed on the surface or inside of the plate-shaped ceramic body, and are formed at positions corresponding to the respective heating resistors of the plate-shaped ceramic body. In a wafer heating apparatus provided with a concave portion and provided with a temperature measuring element in the concave portion, at least one of the plurality of band-shaped resistance heating elements disposed on the outermost periphery of the plate-shaped ceramic body is in the vicinity of the corresponding temperature measuring element. Is smaller than the average power density of the belt-shaped resistance heating element.

  Further, at least one of the plurality of strip-shaped resistance heating elements disposed on the outermost periphery of the plate-shaped ceramic body is provided with a temperature measuring element at a central portion of a region surrounding the resistance heating element. .

  The power density in the vicinity of the temperature measuring element is 40 to 90% of the average power density of the resistance heating element.

  Further, the temperature measuring element is fixed to the recess with a filler having a thermal conductivity of 8.3 to 150% with respect to the thermal conductivity of the plate-shaped ceramic body.

  Further, the porosity of the filler is 0.1% to 50%.

  Further, the thermal expansion coefficient of the filler is 43 to 214% with respect to the thermal expansion coefficient of the plate-shaped ceramic body.

  According to the present invention, a plurality of belt-shaped resistance heating elements are formed on the surface or inside of the plate-shaped ceramic body, and a concave portion is provided at a position corresponding to each resistance heating element of the plate-shaped ceramic body, and a temperature is measured in the concave portion. In the wafer heating device provided with the elements, at least one of the plurality of belt-shaped resistance heating elements disposed on the outermost periphery of the plate-shaped ceramic body has a power density near the corresponding temperature measuring element, and the band-shaped resistance heating element has a resistance. By making the power density lower than the average power density of the heating element, the temperature of the wafer becomes uniform and the amount of overshoot is reduced. Further, the temperature stabilization time until the wafer temperature reaches the set temperature is reduced.

  Furthermore, even when the temperature cycle was repeated, there was little possibility that the temperature stabilization time would change, and excellent characteristics were exhibited.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a cross-sectional view showing an example of a wafer heating apparatus 1 according to the present invention, which is one main plate-shaped ceramic body 2 made of ceramics containing silicon carbide, boron carbide, boron nitride, silicon nitride or aluminum nitride as a main component. The surface is the mounting surface 3 on which the wafer W is mounted, and the resistance heating element 5 is formed on the other main surface 12 via the insulating layer 4 made of glass or resin.

  As the pattern shape of the resistance heating element 5, any pattern shape that can uniformly heat the mounting surface 3, such as a substantially concentric circular or linear concentric or spiral shape, may be used. In order to improve the heat uniformity, it is preferable to divide the resistance heating element 5 into a plurality of resistance heating elements 5a, 5b, 5c, 5d, 5e, and 5f.

  Further, the plate-shaped ceramic body 2 has concave portions 21a, 21b holding the temperature measuring elements 10a, 10b, 10c, 10d, 10e, 10f surrounded by the resistance heating elements 5a, 5b, 5c, 5d, 5e, 5f. , 21c, 21d, 21e and 21f are formed. Each of the temperature measuring elements 10 a, 10 b, 10 c, 10 d, 10 e, and 10 f is a heat-sensitive portion located at the tip of the temperature measuring body 10. Each of these temperature measuring elements 10a, 10b, 10c, 10d, 10e, and 10f is connected to an arithmetic unit 82 and a control unit 81, and calculates a voltage value and the like controlled by the arithmetic unit 82, and controls based on the calculation. A predetermined voltage is applied to each heating element 5 from the section 81 so that the temperature of the wafer W can be made uniform.

  Each of the resistance heating elements 5 is provided with a power supply portion 6 made of a material such as gold, silver, palladium, or platinum, and a conductive terminal 7 is pressed and fixed to the power supply portion 6 via an elastic body 8 so as to be conductive. Is secured.

  Further, a bolt 17 is passed through the outer periphery of the plate-shaped ceramic body 2 and the support 11, and a nut 19 is screwed from the plate-shaped ceramic body 2 side with an elastic body 8 and a washer 18 interposed therebetween, thereby elastically attaching the support 11. Fixed. Accordingly, even if the temperature of the plate-shaped ceramic body 2 is changed or the wafer W is placed on the mounting surface 3 and the temperature of the plate-shaped ceramic body 2 fluctuates, even if the support 11 is deformed, the elastic body 8 can be used. By absorbing this, the warpage of the plate-shaped ceramic body 2 can be prevented, and the occurrence of a temperature difference on the surface of the wafer W can be prevented.

  The support 11 is composed of a plate-like structure 13 composed of a plurality of layers and side walls, and the plate-like structure 13 has a conductive terminal 7 for supplying power to the resistance heating element 5 with an insulating material 9. And an air injection port (not shown) is formed.

Further, embodiments of the present invention will be described in detail. FIG. 2 is a plan view of the plate-shaped ceramic body 2 as viewed from the resistance heating element 5 side. In the plate-shaped ceramic body 2, recesses 21 are formed at positions corresponding to the respective resistance heating elements 5. Is arranged with temperature measuring elements 10a, 10b, 10c and 10d as shown in FIG. 3, and is filled and held by a filler 22 and the like.

That is, a plurality of belt-shaped resistance heating elements 5a, 5b, 5c, 5d, 5e, and 5f are formed on the surface or inside of the plate-shaped ceramic body 2, and the concave portions 21a, 21b, 21c, 21d, 21e, and 21f are provided, and the concave portion 21 is provided with temperature measuring elements 10a, 10b, 10c, and 10d. In the wafer heating apparatus 1, at least one of the strip-shaped resistance heating elements 5a, 5b, 5c, and 5d disposed on the outermost periphery of the plate-shaped ceramic body 2 is used. 5d, for example, the resistance heating element 5a has a power density near the corresponding temperature measuring element 10a smaller than the average power density of the belt-shaped resistance heating element 5a.
The reason is that when the wafer W cooled to room temperature is placed on the plate-shaped ceramic body 2, the temperature of the plate-shaped ceramic body 2 is lowered by the wafer W. At this time, the temperature of the plate-shaped ceramic body 2 is lower at the central portion than at the outer peripheral portion, and therefore, the temperature tends to be large due to the transfer of heat to the wafer W. Therefore, since the power application time at the central portion is longer than the power application time at the outer peripheral portion, the rise of the temperature rises rapidly and overshoots. Therefore, the temperature stabilization time until the temperature of the wafer W stabilizes is long. That is, in the present invention, the time until the temperature of the wafer W becomes stable can be shortened by reducing the power density around the temperature measuring element 10a.

  The above-mentioned power density indicates a power value applied per unit area of each part of the surface 12 where the resistance heating element 5 a is formed on the plate-shaped ceramic body 2. The average power density is a value obtained by dividing the power value obtained from the total resistance value and the current of the resistance heating element 5a by the heating area where the resistance heating element 5a is formed. The heating area of the normal resistance heating element 5a is defined by the middle line between the adjacent resistance heating elements 5b, 5d, 5e, and 5f as a boundary line.

Next, a method of calculating the power density near the temperature measuring element 10a will be described. First, the vicinity of the temperature measuring element 10a means, for example, the center points P1 and P2 of a part of the resistance heating element 5a close to the temperature measuring element 10a and a part of the heating resistance element 5a close to the outside thereof. Element 10
On a straight line passing through the center of a, the distance between the two center points P1 and P2 is M, and the center line is surrounded by two center lines that pass through the center point P1 or P2 and are parallel to the belt-shaped resistance heating element 5a. FIG. 5 shows a region 82 surrounded by the two center lines having a length M. FIG. A region excluding the concave portion 21 from the region 82 is referred to as a region 83. The power density in the vicinity of the temperature measuring element 10a is obtained by dividing the power value obtained from the partial resistance value of the two resistance heating elements 5a in the area 83 and the current flowing therethrough by the area of the area 83. Value.

  The length M is desirably 1.5 to 5 times the diameter of the recess 21 of the plate-shaped ceramic body.

  If the above vicinity is smaller than 1.5 times the diameter of the concave portion 21 of the plate-shaped ceramic body, the temperature difference between the temperature near the temperature measuring element and the entire temperature becomes small, so that the effect of improving the temperature rising characteristic is small. On the other hand, if it is larger than 5 times, the temperature difference between the vicinity of the temperature measuring element and the other area is undesirably large. That is, it is desirable that the length of M, which is a range in the vicinity of the temperature measuring element, is 1.5 to 5 times the outer diameter of the concave portion 21 of the temperature measuring element, and is 1.5 to 5 times the area. In this case, the sensitivity in the vicinity of the temperature measuring element can be increased. That is, the temperature rise curves of the inner and outer resistance heating elements can be made uniform, and the time until the temperature of the wafer W becomes stable can be further reduced.

  More preferably, the power density in the vicinity of the temperature measuring element 10a is desirably 40 to 90% of the power density of the belt-shaped resistance heating element 5a. When the power density ratio in the vicinity of the temperature measuring element 10a is smaller than 40%, the temperature of the plate-shaped ceramic body 2 is transmitted to the control unit when the temperature is low, and the time for applying power is prolonged. Heat transfer (heat radiation) becomes too large, and the temperature of the wafer W becomes higher than a predetermined temperature. The so-called overshoot increases. Conversely, if it is larger than 90%, the temperature measuring element 10a determines that the temperature of the plate-shaped ceramic body 2 in the outer peripheral portion has a small decrease, and the output application time is shortened. Therefore, since the temperature rise in the central portion where power is applied for a long time is fast, the temperature stabilization time until the temperature stabilizes is not longer than 50 seconds, which is not preferable.

  Preferably, in all of the outermost resistance heating elements 5a to 5d, the power density in the vicinity of the corresponding temperature measuring element is preferably smaller than the average power density of each of the resistance heating elements 5a to 5d.

  The adjustment of the power density is performed by changing the line width, thickness, line interval, and the like of the resistance heating element.

  As the temperature measuring elements 10a, 10b, 10c, and 10d, a temperature measuring element, a temperature measuring resistor, or the like can be used. Regarding the material, if it is a thermocouple, Pt / Rh-Pt / Rh system, Pt / Rh-Pt system, Ni / Cr / Si-Ni / Si / Mg system, Ni / Cr-Al / Mn system, Ni / A Cr-Cu / Ni-based, Cu-Cu / Ni-based, W-Re-based, etc., or a Pt resistance element can be used if it is a resistance thermometer. You just have to choose. For example, when used at 300 ° C. or lower in the atmosphere, a Ni / Cr—Al / Mn system, a Pt / Rh—Pt system, a Ni / Cr—Cu / Ni system, or the like is desirable. In a reducing atmosphere, An Fe-Cu / Ni system or the like is desirable.

  Further, as shown in FIG. 3, it is desirable to use a temperature measuring resistor such as a Pt resistance element for the temperature measuring elements 10a, 10b, 10c, and 10d. It is also effective to use a resistive element that is coated with an insulating material such as a resin coat, a glass coat, or a ceramic coat. Further, if necessary, an insulating sleeve or the like may be used after the filling and holding section.

The recess 21a, 21b, 21c, the area of the opening of the ^21d, it is desirable to 1mm ² ~30mm 2. If the area of the openings of the recesses 21a, 21b, 21c, 21d is smaller than 1 mm ² , unevenness is likely to occur in the installation of the temperature measuring elements 10a, 10b, 10c, 10d and the filling of the filler 22, and the temperature measurement varies. On the other hand, if it is larger than 30 mm ² , the gap between the resistance heating elements 5 becomes large, and the temperature distribution on the surface of the wafer W becomes undesirably large.

  Further, it is desirable that the depth d of the recesses 21 a, 21 b, 21 c, and 21 d be (１ ／) t ≦ d ≦ (３) t with respect to the thickness t of the plate-shaped ceramic body 2. If the depth d is smaller than (1/4) t, the distance from the wafer mounting surface becomes large, causing a deviation in the temperature measurement, and the wafer cannot be heated to the target temperature. On the other hand, if it is larger than (3/4) t, the overshoot amount of the temperature becomes too large, which is not desirable.

  Further, it is more preferable that the distance L between the bottom surfaces of the concave portions 21a, 21b, 21c, and 21d and the tips of the corresponding temperature measuring elements 10a, 10b, 10c, and 10d is 0 ≦ L ≦ 1.0 mm. If the distance L exceeds 1 mm, the response of the temperature detection is delayed and the overshoot amount becomes large, but if the distance L is set to 1.0 mm or less, the overshoot amount becomes smaller.

Further, the size of the temperature measuring elements 10a, 10b, 10c, and 10d inserted and installed in the recesses 21a, 21b, 21c, and 21d is desirably 30 mm ² or less. If it is larger than 30 mm ² , the heat capacity of the temperature measuring elements 10 a, 10 b, 10 c, and 10 d itself becomes too large, so that the heat extraction through the wires becomes large, and the temperature detection is delayed, and the amount of overshoot becomes too large. Absent.

  A concave portion 21 is provided at a position corresponding to each resistance heating element 5 of the plate-shaped ceramic body 2, and the position of the temperature measuring elements 10 a, 10 b, 10 c, and 10 d of the concave portion 21 is set at the outermost periphery of the plate-shaped ceramic body 1. Is desirably located in the vicinity of the center of gravity G of the region R surrounding the plurality of belt-shaped resistance heating elements 5 disposed at the center. When the distance from the center of gravity G to the center of the concave portion 21 in the outermost peripheral portion becomes 30% or more of the maximum length L in the diametric direction of the plate-shaped ceramic body 2 in the region R, the resistance heating element on the outer peripheral portion heats the central portion. Is easily collected, and the rise of the outer peripheral portion becomes slow, and it takes a long time to be stabilized, which is not preferable.

  Further, the filler 22 used to hold the temperature measuring elements 10 a, 10 b, 10 c, and 10 d in the concave portion 21 has a thermal conductivity of 8.3 to 150% with respect to the thermal conductivity of the plate-shaped ceramic body 2. Used. When the ratio of the thermal conductivity is less than 8.3%, the speed at which the Joule heat generated from the resistance heating element 5 is transmitted to the mounting surface 3 via the plate-shaped ceramic body 2 is measured via the filler 22. Since the speed transmitted to the temperature elements 10a, 10b, 10c, and 10d is too slow, a delay occurs in temperature detection, and the amount of overshoot becomes too large, which is not preferable. If it exceeds 150%, the speed at which Joule heat is transmitted to the mounting surface 3 via the plate-shaped ceramic body 2 is faster than the speed at which the Joule heat is transmitted to the temperature measuring elements 10a, 10b, 10c, and 10d via the filler 22. Before the mounting surface 3 reaches a predetermined temperature, the temperature measuring elements 10a, 10b, 10c, and 10d detect the temperature, and stop supplying power to the resistance heating element 5 early. As a result, It is not preferable because the temperature rise is slow. More preferably, it is better to use a filler having a thermal conductivity of 25 to 100% with respect to the thermal conductivity of the plate-shaped ceramic body 2.

  Further, the porosity of the filler is preferably in the range of 0.1% to 50%. When the porosity is less than 0.1%, the flexibility of the filler 22 is impaired, and the thermal stress generated between the plate-shaped ceramic body 2 and the filler 22 when a temperature cycle is applied to the wafer heating device 1. When the filler 22 is used for a long period of time, the filler 22 is separated from the plate-shaped ceramic body 2, so that accurate temperature control cannot be performed. On the other hand, if it exceeds 50%, the pores act as a heat insulating material, and the measurement temperature is not easily stabilized. More preferably, when the porosity is 0.5 to 25%, the durability is increased and the overshoot amount is small, which is preferable.

  It is preferable that the porosity is adjusted by removing the entrained bubbles by leaving the container at room temperature for a while after the filling to remove bubbles. In addition, as a method of increasing the porosity, the porosity can be increased by adjusting the number of rotations and the time when a filler such as carbon or metal powder is mixed with the resin.

  Further, the thermal expansion coefficient of the filler 22 is preferably in the range of 50% to 200% with respect to the thermal expansion coefficient of the plate-shaped ceramic body 2. If the coefficient of thermal expansion of the filler 22 is out of the above range, it is not preferable because the temperature measuring element 10 protrudes from the recess 21 due to the stress due to the difference in the coefficient of thermal expansion during repeated heating and cooling. Further, the wettability with the plate-shaped ceramic body 2 is also important. If a gap appears between the temperature measuring element 10 and the concave portion 21, the gap acts as a heat insulating layer, so that an accurate temperature cannot be measured and a time until the temperature reaches a predetermined temperature is not preferable. More preferably, a filler 22 having a coefficient of thermal expansion of 70 to 140% of the coefficient of thermal expansion of the plate-shaped ceramic body 2 is preferably used.

  Further, as the filler 22 used in the present invention, a filler in which a powder having high thermal conductivity such as carbon, aluminum nitride, boron nitride, or metal powder is dispersed in a heat-resistant resin can be used. As described above, since the filler 22 of the type in which the high thermal conductive powder is dispersed in the resin has good fluidity, workability at the time of filling is improved. As the type of the resin, it is preferable to use a resin having a heat resistance temperature of 300 ° C. or more, such as polyimide, polyamide, or polyimide amide. On the other hand, when an epoxy resin, a silicon resin, or the like having a heat resistance temperature of 200 ° C. or less is used, the bonding strength is high, but the resin is carbonized and brittle during use, and the temperature measuring elements 10a, 10b, 10c, and 10d are peeled off. As a result, an accurate temperature cannot be measured. In addition, cements such as alumina cement can be used as the filler 22 if they are filled so as not to impair the thermal conductivity.

  Further, in FIG. 1, the metal support 11 has a side wall and a plate-like structure 13, and the plate-like structure 13 has an opening corresponding to 5 to 50% of its area. . In addition, the plate-like structure 13 may further include, as necessary, a conduction terminal 7 for conducting with a power supply portion 6 for supplying power to the resistance heating element 5 of the plate-like ceramic body 2; And a temperature measuring element 10 for measuring the temperature of the plate-shaped ceramic body 2 are installed.

  Further, lift pins (not shown) are installed in the support 11 so as to be able to move up and down, and are used to place the wafer W on the mounting surface 3 and to lift the wafer W from the mounting surface 3. In order to heat the semiconductor wafer W by the wafer heating device 1, the wafer W carried above the mounting surface 3 by the transfer arm (not shown) is supported by the lift pins, and the lift pins are lowered to move the wafer W On the mounting surface 3. Next, power is supplied to the power supply unit 6 to cause the resistance heating element 5 to generate heat, and the wafer W on the mounting surface 3 is heated via the insulating layer 4 and the plate-shaped ceramic body 2.

  At this time, according to the present invention, the plate-shaped ceramic body 2 is formed of a silicon carbide-based sintered body, a boron carbide-based sintered body, a boron nitride-based sintered body, a silicon nitride-based sintered body, or an aluminum nitride-based sintered body. Since it is formed by heat treatment, the deformation is small even when heat is applied, and the plate thickness can be reduced, so that the heating time until heating to the predetermined processing temperature and the cooling until cooling from the predetermined processing temperature to around room temperature are performed. Time can be shortened, productivity can be increased, and since it has a thermal conductivity of 60 W / (m · K) or more, the Joule heat of the resistance heating element 5 can be quickly transmitted even with a small thickness, Temperature variation of the mounting surface 3 can be extremely reduced. In addition, since it does not react with moisture in the atmosphere to generate gas, even when used for attaching a resist film on a semiconductor wafer, it does not adversely affect the structure of the resist film and allows fine wiring. Can be formed at a high density.

  By the way, in order to satisfy such characteristics, the plate thickness of the plate-shaped ceramic body 2 is preferably set to 1 mm to 7 mm. This is because if the plate thickness is less than 1 mm, the plate thickness is too small, and the temperature variation is leveled, so that the effect as the plate-shaped ceramic body 2 is small, and the variation of the Joule heat in the resistance heating element 5 is directly mounted. This is because it appears as a temperature variation of the surface 3 and it is difficult to equalize the temperature of the mounting surface 3. Conversely, if the plate thickness exceeds 7 mm, the heat capacity of the plate-shaped ceramic body 2 becomes too large, and the temperature becomes a predetermined processing temperature. This is because the time required to increase the temperature before heating or the cooling time when changing the temperature becomes long, and the productivity cannot be improved.

  Further, in the wafer heating apparatus 1 of the present invention described in detail above, as shown in FIG. 1, a resistance heating element 5 is formed on a surface of a plate-shaped ceramic body 2 with an insulating layer 4 interposed therebetween. Since it is exposed, the resistance value can be adjusted by trimming the resistance heating element 5 so that the temperature distribution on the mounting surface 3 becomes uniform according to the use conditions and the like.

Further, as the ceramic forming the plate-shaped ceramic body 2, a ceramic mainly containing at least one of silicon carbide, boron carbide, boron nitride, silicon nitride, and aluminum nitride can be used. Examples of the silicon carbide sintered body include a sintered body containing boron (B) and carbon (C) as a sintering aid for silicon carbide as a main component, and a sintering aid for silicon carbide as a main component. As an agent, a sintered body containing alumina (Al ₂ O ₃ ) and yttria (Y ₂ O ₃ ) and fired at 1900 to 2200 ° C. can be used, and silicon carbide mainly containing α-type, or Any of those mainly composed of β-type may be used.

  Further, as the boron carbide sintered body, a sintered body is obtained by mixing 3 to 10% by weight of carbon as a sintering aid with boron carbide as a main component and performing hot press firing at 2000 to 2200 ° C. be able to.

  As the boron nitride sintered body, 30 to 45% by weight of aluminum nitride and 5 to 10% by weight of a rare earth element oxide are mixed as a sintering aid with respect to boron nitride as a main component, and 1900 to 2100%. A sintered body can be obtained by hot press sintering at ℃. As another method for obtaining a sintered body of boron nitride, there is a method in which borosilicate glass is mixed and sintered, but this method is not preferable because the thermal conductivity is significantly reduced.

Further, as the silicon nitride sintered body, 3 to 12% by weight of a rare earth element oxide and 0.5 to 3% by weight of Al ₂ O ₃ as a sintering aid are added to silicon nitride as a main component. The sintered body can be obtained by mixing SiO ₂ so that the amount of SiO ₂ contained in the binder becomes 1.5 to 5% by weight and performing hot press firing at 1650 to 1750 ° C. Here, the SiO ₂ amount indicated, the SiO ₂ generated from oxygen impurity contained in the silicon nitride in the raw material, and SiO ₂ as an impurity contained in other additives, are deliberately SiO ₂ in total added .

Further, as the aluminum nitride sintered body, a rare earth element oxide such as Y ₂ O ₃ or Yb ₂ O ₃ as a sintering aid and an alkaline earth element such as CaO if necessary It is obtained by adding a metal oxide, mixing well, processing into a plate shape, and then firing at 1900 to 2100 ° C. in nitrogen gas.

  These sintered bodies are used by selecting a material according to the intended use. For example, when used for drying a resist film, the nitride reacts with moisture to generate ammonia gas, which has an adverse effect on the resist film and cannot be used. Further, in the case of a wafer heating apparatus for CVD that may be used at a high temperature of about 800 ° C., a boron nitride-based material containing a large amount of glass is deformed during use so that the plate-like ceramic body 2 is deformed. May be compromised.

  Further, the main surface of the plate-shaped ceramic body 2 opposite to the mounting surface 3 has a flatness of 20 μm or less and a surface roughness of a center line average roughness from the viewpoint of enhancing the adhesion to the insulating layer 4 made of glass or resin. It is preferable that the surface is polished to a thickness (Ra) of 0.1 μm to 0.5 μm.

  On the other hand, when the silicon carbide sintered body is used as the plate-shaped ceramic body 2, the insulating layer 4 for maintaining the insulation between the plate-shaped ceramic body 2 having some conductivity and the resistance heating element 5 is made of glass or resin. When glass is used, if the thickness is less than 100 μm, the withstand voltage is below 1.5 kV, and the insulating property cannot be maintained. Conversely, if the thickness exceeds 500 μm, the plate-like ceramic body 2 is formed. Since the thermal expansion difference between the silicon carbide-based sintered body and the aluminum nitride-based sintered body becomes too large, cracks are generated and the insulating layer 4 does not function. Therefore, when glass is used as the insulating layer 4, the thickness of the insulating layer 4 is preferably in the range of 100 μm to 500 μm, and more preferably in the range of 150 μm to 400 μm.

When the insulating layer 4 is formed on the surface of the plate-shaped ceramic body 2 made of the silicon carbide sintered body, the surface is oxidized in advance to form an oxide film made of SiO ₂ having a thickness of 0.01 to ₂ μm. Further, an insulating layer 4 is formed on the surface. When the plate-shaped ceramic body 2 is formed of a ceramic sintered body containing aluminum nitride as a main component, the adhesion of the resistance heating element 5 to the plate-shaped ceramic body 2 In order to improve the quality, the insulating layer 4 made of glass is formed. However, when sufficient glass is added to the resistance heating element 5 and a sufficient adhesion strength can be obtained by this, it can be omitted.

  Next, when a resin is used for the insulating layer 4, if the thickness is less than 30 μm, the withstand voltage falls below 1.5 kV, the insulating property cannot be maintained, and the resistance heating element 5 is trimmed by laser processing or the like. When the thickness exceeds 400 μm, the amount of solvent and water generated during baking of the resin increases, and the insulating layer 4 is damaged. A bubble-like peeling portion called “foamed portion” is formed, and the presence of the peeling portion deteriorates heat transfer. Therefore, when a resin is used as the insulating layer 4, the thickness of the insulating layer 4 is preferably formed in the range of 30 μm to 400 μm, and more preferably in the range of 60 μm to 200 μm.

  In addition, as the resin forming the insulating layer 4, polyimide resin, polyimide amide resin, polyamide resin, and the like are preferable in consideration of heat resistance of 200 ° C. or more and adhesion to the resistance heating element 5.

  As a means for applying the insulating layer 4 made of glass or resin on the plate-shaped ceramic body 2, a suitable amount of the glass paste or resin paste is dropped on the center of the plate-shaped ceramic body 2 and stretched by a spin coating method. Or evenly by screen printing, dipping, spray coating, etc., then at 600 ° C for glass paste and 300 ° C or higher for resin paste Baking at the temperature. When glass is used as the insulating layer 4, the surface of the plate-shaped ceramic body 2 made of a silicon carbide-based sintered body or a boron carbide-based sintered body is heated in advance to a temperature of about 1200 ° C. By oxidation treatment, the adhesion to the insulating layer 4 made of glass can be enhanced.

Further, as the resistance heating element 5 to be deposited on the insulating layer 4, a simple metal such as gold (Au), silver (Ag), copper (Cu), palladium (Pd) is directly applied by a vapor deposition method or a plating method. A resin paste or a glass paste containing the above-mentioned metal alone or an oxide such as rhenium oxide (Re ₂ O ₃ ) or lanthanum manganate (LaMnO ₃ ) as a conductive material is prepared, and the screen is formed into a predetermined pattern shape. After printing by a printing method or the like, the conductive material may be bonded by a matrix made of resin or glass by baking. When glass is used as the matrix, either crystallized glass or amorphous glass may be used, but it is preferable to use crystallized glass in order to suppress a change in resistance due to thermal cycling.

  However, when silver or copper is used for the resistance heating element 5, migration may occur. In such a case, the same material or the same resistance heating element 5 as the insulating layer 4 is used to cover the resistance heating element 5. A protective film made of a material equivalent to the matrix component may be coated with a thickness of about 30 μm.

  In addition, as for the plate-shaped ceramic body 2 of the type in which the resistance heating element 5 is incorporated, it is preferable to use an aluminum nitride sintered body having high thermal conductivity and high electrical insulation. In this case, a raw material containing aluminum nitride as a main component and appropriately containing a sintering agent is sufficiently mixed, and then molded into a disk shape, and a paste made of W or WC is printed on the surface thereof in a pattern shape of the resistance heating element 5, After another aluminum nitride molded body is overlaid and adhered thereon, it is fired at a temperature of 1900 to 2100 ° C. in nitrogen gas to obtain the plate-shaped ceramic body 2 having the resistance heating element 5 built-in. In addition, conduction from the resistance heating element 5 may be achieved by forming a through hole in the aluminum nitride base material, embedding a paste made of W or WC, and firing the paste to draw out the electrode to the surface.

The properties of the glass forming the insulating layer 4 may be either crystalline or amorphous. For example, when used for resist drying, the glass has a heat resistant temperature of 200 ° C. or higher and a temperature range of 20 ° C. to 200 ° C. It is preferable to appropriately select and use one having a coefficient of thermal expansion in the range of -5 to + 5 × 10 ⁻⁷ / ° C. with respect to the coefficient of thermal expansion of the ceramics constituting the plate-shaped ceramic body 2. That is, if a glass having a coefficient of thermal expansion outside the above range is used, the difference in thermal expansion from the ceramics forming the plate-shaped ceramic body 2 becomes too large. This is because defects such as cracks and peeling easily occur.

  Manufacture a plurality of silicon carbide sintered bodies with a thermal conductivity of 100 W / (m · K), disk-shaped plate-shaped ceramic bodies with a plate thickness of 4 mm and an outer diameter of 300 mm, and measure the temperature of each block of the resistance heating element A depth of 2.3 mm × 1 mmφ recess for installing a temperature measuring element for processing is performed. Thereafter, an oxide film is formed on the surface by an oxidation treatment at 1000 ° C. for 2 hours, and an insulating layer is applied to one main surface of each plate-shaped ceramic body. A glass paste prepared by kneading terpineol as a paste was laid by screen printing, heated to 150 ° C. to dry the organic solvent, and then degreased at 550 ° C. for 30 minutes. By baking at a temperature, an insulating layer made of glass and having a thickness of 200 μm was formed.

  Then, in order to apply a resistance heating element on the insulating layer, a glass paste to which Au powder and Pt powder are added as a conductive material is printed in a predetermined pattern shape by a screen printing method, and then heated to 150 ° C. The solvent was dried, degreased at 550 ° C. for 30 minutes, and baked at a temperature of 700 to 900 ° C. to form a resistance heating element having a thickness of 50 μm. The number of resistance heating elements was six, with two at the center and four at the outer periphery in the circumferential direction. In order to confirm the influence of the power density due to the resistance heating element around the temperature measuring element, the wafer heating apparatus is used in which the power density around the temperature measuring element is 20% to 120% with respect to the average power density of the individual resistance heating elements. Was prepared. Thereafter, the power supply portion was fixed to the resistance heating element with a conductive adhesive to produce a plate-shaped ceramic body.

  Thereafter, a temperature measuring element composed of a resistance element was embedded in the concave portion of the temperature measuring portion of each resistance heating element so that the tip temperature measuring portion was in contact with the bottom of the concave portion, and a filler was filled therebetween. As this filler, a resin (polyimide) was poured and fixed.

  As the support, two plate-like structures made of stainless steel having a thickness of 2.5 mm and having an opening formed in 30% of the main surface are prepared, and ten conductive terminals are provided on one of the plate-like structures. , And fixed to the side wall portion also made of stainless steel with screws to prepare a support.

  Then, on the support, the concave portion is formed at a substantially central portion of the heat generating pattern forming portion, a temperature measuring element is installed, and a plate-like ceramic body held and fixed with an inorganic filler is overlapped. Was heated with a screw through an elastic body.

  Then, a power supply portion made of a gold paste was formed by a transfer method, and baked at 900 ° C.

  Here, the influence of the power density ratio and the arrangement of the temperature measuring elements was investigated. The material of the plate-shaped ceramic body is aluminum nitride, the power density ratio of each wafer heating device is 90%, 100%, 110%, and the center of gravity G of the strip-shaped heating element at the position of the concave portion of the plate-shaped ceramic body. The wafer heating device was manufactured by changing the deviation amount X of the resistance heating element to 0%, 10%, 20%, and 30% of the width in the diameter direction of the plate-shaped ceramic body. Then, a current is supplied to the conductive terminals of the wafer heating apparatus obtained in this way and the temperature is maintained at 150 ° C., and the temperature distribution on the surface of the wafer placed on the mounting surface is set to be equal to the center of the wafer and 1/3 of the radius of the wafer. The temperature setting of the temperature controller is corrected for each resistance heating element so that the temperature variation of 17 points, that is, 16 points of 8 division points on the circumference of 2/3 is within 1 ° C, and the setting variation is confirmed. did. In addition, after the wafer is removed and held by the wafer heating device alone for 60 minutes or more, the wafer W maintained at room temperature is put into the heating device, and the wafer W is overheated from the moment it is placed on the mounting surface until it is stabilized at 150 ° C. The amount of shoot and the temperature stabilization time until the temperature was stabilized at 150 ± 0.5 ° C. were measured five times for each sample, and the maximum value was taken as the measured value.

Each result is as shown in Table 1.

  As can be seen from Table 1, sample no. The wafer heating devices 1 and 2 detect that the temperature of the resistance heating element is high because the power density around the temperature measuring element is too large, and the time required for output is short, so the temperature of the outer peripheral portion rises slowly. However, the overshoot amount was large at 2 ° C. and 2.6 ° C., and the temperature stabilization time was 61 seconds and 67 seconds, which was not preferable.

  On the other hand, the position of the concave portion of the plate-shaped ceramic body is set such that the circumferential shift amount X of the center of gravity G of the strip-shaped heating element is 20 degrees, and the radial shift amount Y is set to the inner side of the width of the resistive heating element of the recess. %, Outer 20%, power density ratio is smaller than 100%. In Nos. 3 to 5, the overshoot amount was less than 2 ° C., and the temperature stabilization time was 48 seconds or less, indicating good transient characteristics.

  In addition, as a result of a test in which the arrangement of the temperature measuring element was changed, the position of the concave portion of the plate-shaped ceramic body was changed to the sample No. in which the displacement X of the center of gravity G of the strip-shaped heating element was 30%. In Sample No. 6, the time required for the wafer temperature to stabilize was slightly longer at 51 seconds, whereas in Sample No. 6 4 and 5 were 45 seconds and 46 seconds, which were small and preferred.

  Here, the influence of the arrangement of the temperature measuring element was investigated. The material of the plate-shaped ceramic body is aluminum nitride, and the area near the temperature measuring element of the resistance heating element of the plate-shaped ceramic body of each wafer heating device is 1.25, 1.5, The resistance was adjusted by changing the area to 5, 7.5 times, and a wafer heating device was manufactured. The position of the temperature measuring element was located at the center of gravity of each resistance heating element. Electricity was supplied to the conductive terminals of the wafer heating apparatus thus obtained and the temperature was maintained at 150 ° C., and the temperature was adjusted in the same manner as in Example 1. Also, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is put into the heating device, and from when the wafer W is placed on the mounting surface until it is stabilized at 150 ± 0.5 ° C. The temperature stabilization time was measured five times for each sample, and the maximum value was taken as the measured value.

The results are shown in Table 2.

  As can be seen from Table 2, sample no. In Nos. 21 and 24, the time until stabilization is not improved. On the other hand, the area near the temperature measuring element is 1.5 to 5 times larger than the concave diameter. Samples Nos. 22 and 23 were preferable because the time until stabilization was 43 seconds or less.

  Here, the influence of the power density ratio in the vicinity of the temperature measuring element was investigated. The material of the plate-shaped ceramic body is aluminum nitride, the deviation X from the center of gravity G of the temperature measuring element is 0%, and the power density ratio (power density around the temperature measuring element / average power density of the resistance heating element) is 30%. Wafer heating devices were made with a range of ~ 95%.

  Electricity was supplied to the conductive terminals of the wafer heating apparatus thus obtained and the temperature was maintained at 150 ° C., and the temperature was adjusted in the same manner as in Example 1. Also, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is put into the heating device, and from when the wafer W is placed on the mounting surface until it is stabilized at 150 ± 0.5 ° C. The temperature stabilization time was measured five times for each sample, and the maximum value was taken as the measured value.

The results are shown in Table 3.

As can be seen from Table 3, sample no. The wafer heating device 31 places the wafer W maintained at room temperature on the mounting surface heated to 150 ° C., and the amount of overshoot of the wafer W from the moment when the wafer W is mounted on the mounting surface to stabilization at 150 ° C. is 1 The temperature was slightly large at 0.7 ° C., and the time required for stabilization to 150 ± 0.5 ° C. was also slightly large at 43 seconds. This is because the power density around the temperature measuring element is smaller than the average power density, so that it is detected that the initial temperature is low and the output time is long after that, so that the amount of overshoot exceeding 150 ° C. is 1.7. It is considered that the temperature became large.

  Further, the sample No. In No. 32, the temperature stabilization time was 43 seconds, and the overshoot amount was slightly large at 1.1 ° C.

  On the other hand, the sample No. In Nos. 32 to 36, the overshoot amount was less than 1.5 ° C., and the temperature stabilization time was as small as 42 or less, indicating good transient characteristics.

  Therefore, it has been found that the power density near the temperature measuring element is preferably 40 to 90% of the average power density of the resistance heating element.

  Here, the influence of the thermal conductivity of the filler for fixing the temperature measuring element was investigated. As this filler, a powder of Al, Cu, Ni or the like having a thermal conductivity of 230 to 420 W / (m · K) is appropriately dispersed so that the thermal conductivity becomes 1 to 150 W / (m · K). Resin (polyimide), ceramic cement (alumina cement), and brazing material (Au-Cu brazing, Ag-Cu brazing) were poured and fixed. Using the filler prepared in this manner, a temperature measuring element was fixed to the concave portion of each plate-shaped ceramic body, and a wafer heating device was manufactured.

  The power density around the temperature measuring element of the manufactured wafer heating device was set to 80% with respect to the average power density of the individual resistance heating elements.

  The temperature was adjusted in the same manner as in Example 1. Further, the wafer W maintained at room temperature is put into a wafer heating device, and the amount of overshoot of the wafer W from the moment it is placed on the mounting surface until it is stabilized at 150 ° C., and is stabilized at 150 ± 0.5 ° C. The temperature stabilization time until was measured. Further, 10,000 temperature cycles were performed in which the temperature was raised from 40 ° C. or lower to 250 ° C. in 2 minutes, and forced air cooling was performed to 40 ° C. or lower in 3 minutes. Thereafter, the wafer W maintained at room temperature is put on the mounting surface of the wafer heating device at 150 ° C., and the amount of overshoot of the wafer W from the moment when the wafer is mounted on the mounting surface until it is stabilized at 150 ° C. The temperature stabilization time until stabilization at ± 0.5 ° C. was measured.

The results are as shown in Table 4.

  As can be seen from Table 4, sample no. In the wafer heating devices 41, 42, 51, and 52, since the thermal conductivity of the filler is small and the response is poor, the overshoot amount is slightly large at 1.2 to 1.6 ° C., and the temperature stabilization time is 39 to It was a little big for 40 seconds.

  Further, the sample No. In Nos. 49, 50 and 60, since the thermal conductivity of the filler was large, the heat generated by the resistance heating element was quickly transmitted to the temperature measuring element, and the temperature stabilization time was slightly longer at 40 seconds.

  On the other hand, the sample No. in which the thermal conductivity of the filler was 8.3 to 150% with respect to the thermal conductivity of the plate-shaped ceramic body. Nos. 43 to 48 and Nos. 54 to 59 show that the amount of overshoot of the wafer W from the moment when the wafer W kept at the normal temperature is put into the heating device and placed on the mounting surface until it is stabilized at 150 ° C. is 1.1. ° C or less, and the temperature stabilization time until the temperature was stabilized at 150 ± 0.5 ° C was also 37 seconds or less, and even better results were obtained.

  Here, the influence of the porosity of the filler for fixing the temperature measuring element was investigated. The filler is made of a polyimide resin in which carbon having an average particle diameter of 1.0 μm is dispersed, and the porosity of the filler is adjusted to 0.1 to 50% by adjusting the stirring speed and the degree of vacuum defoaming during mixing. Adjusted between. The porosity was obtained by separately solidifying the resin that was simultaneously adjusted, measuring the bulk specific gravity thereof, and converting the difference from the theoretical density obtained from the mixing ratio into the porosity. Using the filler thus adjusted, a temperature measuring element was fixed to the concave portion of each plate-shaped ceramic body, and a wafer heating device was manufactured.

  Then, the amount of overshoot and the temperature stabilization time before the temperature cycle test were measured in the same manner as in Example 1. In the temperature cycle test, the temperature was raised from 40 ° C. or lower to 250 ° C. in 2 minutes, and forced air cooling to 40 ° C. or lower in 3 minutes was performed as one cycle. The evaluation method is the same as that of the first embodiment. After the mounting surface of the wafer heating apparatus is heated to 150 ° C. for 1 hour or more after the temperature cycle test of 10,000 times, the wafer W maintained at the normal temperature is removed by the wafer heating apparatus. The sample was placed on the placing surface, and the temperature stabilization time from the moment of placing on the placing surface to stabilization at 150 ± 0.5 ° C. was measured five times for each sample, and the maximum value was taken as the measured value.

Table 5 shows the results.

  As can be seen from Table 5, the sample No. having the pores of 0.05%. Reference numeral 61 denotes a temperature stabilization time of 36 seconds from the moment when the wafer W maintained at room temperature was put into the heating device and was placed on the mounting surface before being stabilized at 150 ± 0.5 ° C. before the temperature cycle test. However, the result after a temperature cycle test of 10,000 cycles was 41 seconds. This is considered to be due to the fact that when the number of temperature cycles increases, the filler comes off from the recess due to the difference in thermal expansion between the plate-shaped ceramic body and the filler. Sample No. with a porosity of the filler of 60%. In the case of No. 69, the temperature stabilization time before the heat cycle was good at 37 seconds, but it was 40 seconds after 10,000 times of the temperature cycles.

  On the other hand, the sample No. in which the porosity of the filler was 0.1 to 50%. In Nos. 62 to 68, the amount of change in the temperature stabilization time due to the temperature cycle was small and stable. This indicates that the pores improve the elasticity of the filler and absorb the stress caused by the difference in thermal expansion between the filler and the ceramic substrate.

Here, the influence of the thermal expansion coefficient of the filler for fixing the temperature measuring element was investigated. Each of the plate-shaped ceramics of each wafer heating device is formed by using a filler whose material is aluminum nitride and whose coefficient of thermal expansion is changed to 1.5 to 14.3 × 10 ⁻⁶ / ° C. The temperature measuring element was fixed in the concave portion of the body, and a wafer heating device was manufactured.

  Electricity was supplied to the conductive terminals of the wafer heating apparatus thus obtained and the temperature was maintained at 150 ° C., and the temperature was adjusted in the same manner as in Example 5. Also, after removing the wafer and holding it for 60 minutes or more only with the wafer heating device, the wafer W maintained at room temperature is put into the heating device, and from when the wafer W is placed on the mounting surface until it is stabilized at 150 ± 0.5 ° C. The temperature stabilization time was measured five times for each sample, and the maximum value was taken as the measured value.

  In addition, 10,000 temperature cycles were performed in the same manner as in Example 5, and the temperature stabilization time was measured. Specifically, the evaluation was performed using a filler obtained by dispersing a metal such as carbon, Al, or Cu in a polyimide resin having a thermal conductivity of 1 W / (m · K) as a filler.

The results are shown in Table 6.

  As can be seen from Table 6, Sample No. 2 in which the thermal expansion coefficient of the filler was 29% of the thermal expansion coefficient of the plate-shaped ceramic body. No. 71 having a thermal expansion coefficient of 286%. With 79, the temperature stabilization time before the cycle was excellent as 34 seconds and 35 seconds, but the temperature stabilization time after 10,000 cycles was as large as 41 seconds and 40 seconds. Sample No. Since the ratio of the thermal expansion coefficients of 71 and 79 was large, the temperature measurement element was moved by the thermal cycle, and the temperature stabilization time was slightly longer.

  On the other hand, the sample No. having the thermal expansion coefficient ratio of 43 to 214%. Nos. 72 to 78 are Nos. Since it is difficult for the temperature measuring element to move due to the thermal cycle as in the cases of 71 and 79, it has been found that the possibility that the temperature cycle becomes longer due to the temperature cycle is small and this is preferable.

It is a sectional view showing the wafer heating device of the present invention. FIG. 3 is a plan view showing a plate-shaped ceramic body of the wafer heating device of the present invention. It is sectional drawing which shows the temperature measuring element installation part of the wafer heating apparatus of this invention. It is sectional drawing which shows the conventional wafer heating apparatus.

Explanation of reference numerals

1: Wafer heating device 2: Plate-shaped ceramic body 3: Mounting surface 4: Insulating layer 5: Resistance heating element 6: Power supply unit 7: Conductive terminal 8: Elastic body 10: Temperature measuring element 11: Support body 21: Concave part 22 : Filler 81: Control unit 82: Storage unit W: Semiconductor wafer t: Thickness

Claims (6)

A plurality of belt-shaped resistance heating elements are formed on the surface or inside of the plate-shaped ceramic body, a recess is provided at a position corresponding to each resistance heating element of the plate-shaped ceramic body, and a wafer heating element having a temperature measuring element in the recess is provided. In the apparatus, at least one of the plurality of strip-shaped resistance heating elements disposed on the outermost periphery of the plate-shaped ceramic body has a power density near a corresponding temperature measuring element, and an average power of the strip-shaped resistance heating elements. A wafer heating device having a lower density. The at least one of the plurality of belt-shaped resistance heating elements disposed on the outermost periphery of the plate-shaped ceramic body has a temperature measuring element at a center of a region surrounding the resistance heating element. 2. The wafer heating device according to 1. 3. The wafer heating apparatus according to claim 1, wherein a power density near the temperature measuring element is 40 to 90% of an average power density of the resistance heating element. 4. 4. The temperature measuring element is fixed to the recess with a filler having a thermal conductivity of 8.3 to 150% with respect to a thermal conductivity of the plate-shaped ceramic body. The wafer heating device as described in the above. The wafer heating apparatus according to claim 4, wherein the porosity of the filler is 0.1% to 50%. The wafer heating apparatus according to claim 4, wherein a thermal expansion coefficient of the filler is 43% to 214% with respect to a thermal expansion coefficient of the plate-shaped ceramic body.

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