JP2016225015A - Heating device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device capable of improving in-plane soaking properties of a holder by reducing heat escape from the holder to a cylindrical support.SOLUTION: A heating device 11 comprises a ceramic holder 21 and a ceramic cylindrical support 31. The holder 21 includes a principal surface 22 on which a processed base material 15 is mounted and a rear surface 23, and is embedded with a resistance heating element 25. An end surface 32 of the cylindrical support 31 is joined to the rear surface 23 of the holder 21. An airtight air gap 41 isolated from the outside is formed in a junction portion B1 between the holder 21 and the cylindrical support 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heating device and a manufacturing method thereof, and more particularly to a heating device characterized by the structure of a joint portion between a ceramic holder and a ceramic cylindrical support and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, semiconductor manufacturing apparatuses such as film forming apparatuses such as plasma CVD, thermal CVD, photo CVD, ALD, and sputtering and etching apparatuses such as plasma etching and photo etching are well known. This semiconductor manufacturing apparatus includes a heating device (so-called susceptor) for heating to various processing temperatures while holding a semiconductor wafer or the like as a substrate to be processed.

  Generally, this type of heating device includes a ceramic holder and a ceramic cylindrical support. A semiconductor wafer can be placed on the main surface of the holding body, and one end face of the cylindrical support is bonded and fixed to the center of the back surface of the holding body. A resistance heating element is embedded in the holder, and a semiconductor wafer mounted on the main surface is heated to several hundred degrees Celsius by energizing the resistance heating element. In recent years, there has been proposed a heating device in which a ring-shaped gap is formed in a joint portion between a ceramic holder and a ceramic cylindrical support (see, for example, Patent Document 1). Since the gap in the heating device is a gas supply path for flowing backside gas or purge gas, it communicates with an external region through a communication hole provided in the cylindrical support.

JP 2003-142564 A

  By the way, in recent semiconductor manufacturing processes, there is a demand for improvement of in-plane temperature uniformity (in-plane thermal uniformity) with respect to a holder for performing heat treatment of a substrate to be processed in order to improve pattern miniaturization and yield. Is growing. Specifically, it is expected that the in-plane thermal uniformity on the main surface of the holding body is within ± 1.0%, and further within ± 0.5%. However, since the heat generated by the resistance heating element in the holding body escapes through the cylindrical support (that is, “heat escapes”), the temperature of the holding body is greatly reduced at the joint portion with the cylindrical support. End up. Therefore, in the conventional heating device, the in-plane heat uniformity of the holding body has been inevitably deteriorated due to its structure.

  On the other hand, in the case of the heating device of Patent Document 1, there is a possibility that heat insulation can be improved by having a gap in the joint portion, and heat escape can be improved. However, since this gap is a gas supply path, the holding body is reversed. It takes away the heat and worsens the in-plane thermal uniformity. Therefore, even if any of the above-described conventional heating device and the heating device of Patent Document 1 is used, the semiconductor wafer cannot be uniformly heat-treated, and the degree of processing tends to vary. As a result, there is a problem that the yield is reduced.

  The present invention has been made in view of the above problems, and its purpose is to reduce the heat escape from the holding body to the cylindrical support body, thereby improving the in-plane heat uniformity of the holding body. It is to provide an apparatus and a manufacturing method thereof.

  And as means (means 1) for solving the above-mentioned problems, the ceramic holding body having the main surface and the back surface on which the substrate to be treated is placed, the resistance heating element is embedded, and the end surface are the above-mentioned A cylindrical support body made of ceramic bonded to the back surface, and an airtight gap isolated from the outside is formed in a joint portion between the holding body and the cylindrical support body. There is a heating device.

  Therefore, according to the invention described in the means 1, there is an airtight gap isolated from the outside at the joint portion between the holding body and the cylindrical support body, and this portion has a heat insulating structure. . As a result, the cross-sectional area of the heat escape path from the holding body to the cylindrical support body is reduced, and the in-plane heat uniformity on the substrate on which the substrate to be treated is placed is improved.

  In the present invention, the substrate to be treated refers to a substrate that is placed on a holder and heat-treated, and its size, shape, material, etc. are not particularly limited, but for example, a plate shape made of an inorganic material A substrate can be exemplified. Specifically, semiconductor wafers made of silicon, arsenic gallium, silicon carbide, sapphire, etc., metal wafers made of aluminum, iron, or the like can be cited as preferred examples.

  Both the holding body and the cylindrical support are made of ceramic. The type of ceramic constituting these members is not limited. For example, a sintered body mainly composed of a high-temperature fired ceramic such as alumina, yttria (yttrium oxide), aluminum nitride, boron nitride, silicon carbide, or silicon nitride is suitable. As an example. Moreover, according to a use, you may select the sintered compact which has as a main component the low-temperature baking ceramic like the glass ceramic which added inorganic ceramic fillers, such as an alumina, to the borosilicate glass or lead borosilicate glass. Or you may select the sintered compact which has dielectric ceramics, such as barium titanate, lead titanate, and strontium titanate, as a main component.

  In each process such as dry etching in the semiconductor manufacturing process, various techniques using plasma are employed, and in the process using plasma, corrosive gas such as halogen gas is frequently used. For this reason, in addition to heat resistance (for example, 700 ° C. or higher), a high corrosion resistance is required for a heating apparatus for a semiconductor manufacturing apparatus such as a susceptor exposed to a corrosive gas or plasma. Therefore, the holding body and the cylindrical support are preferably made of a material having corrosion resistance against corrosive gas or plasma, for example, a material mainly composed of aluminum nitride, alumina, or yttria.

  The material of the conductor constituting the resistance heating element embedded in the holding body is not particularly limited. For example, when the ceramic material constituting the holding body and the cylindrical support is made of a so-called high-temperature fired ceramic (for example, alumina). Can select nickel (Ni), tungsten (W), molybdenum (Mo), manganese (Mn), or an alloy thereof as a metal constituting the resistance heating element. When the ceramic material constituting the holding body and the cylindrical support is made of a so-called low-temperature fired ceramic (for example, glass ceramic), the metal constituting the resistance heating element is copper (Cu), silver (Ag), or the like. These alloys can be selected. When the ceramic material constituting the holding body and the cylindrical support is made of a high dielectric constant ceramic (for example, barium titanate), nickel (Ni), copper (Cu), silver (Ag), palladium (Pd ), Platinum (Pt), and the like, and alloys thereof. The resistance heating element can be formed by using a conductive paste containing a metal powder and applying the paste by a conventionally known method, for example, a printing method, followed by baking.

  In the present invention, the back surface of the holder and the end surface of the cylindrical support are solid-phase bonded. In this joining, a known joining agent, for example, a material containing a sintering aid such as alkaline earth, rare earth, aluminum composite oxide or the like is used. Such a bonding agent is mixed with an organic solvent or the like to form a paste, which is uniformly printed on the bonding surface of the holding body or the cylindrical support, and then degreased. In addition, the back surface of the holding body and the end surface of the cylindrical support body can be bonded by a method such as brazing or glass bonding.

  In the present invention, a gap is formed in the joint portion between the holding body and the cylindrical support. This gap serves to block a part of the heat escape path from the holding body to the cylindrical support. The gap may be formed on either the end surface of the cylindrical support and the back surface of the holding body, or may be formed on both. The air gap in this heating device is an airtight air gap isolated from the outside. In other words, the gap itself is an independent space and does not communicate with any area. In other words, this gap is a completely closed space where no fluid flows in and out.

  The gap is preferably formed by a recess provided in the end face of the cylindrical support. This is because a resistance heating element is embedded on the holding body side, so that it is necessary to form a recess avoiding the resistance heating element, and the position where the recess is formed may be restricted. On the other hand, since the resistance heating element does not exist on the end face of the cylindrical support, it is difficult to be restricted in the formation position of the recess, and it is easier to manufacture compared to the case where the recess is provided on the holding body side.

  The void may be in a vacuum state where no gas is present, but may be present. When the space is in a vacuum state, extremely high heat insulation performance can be imparted, and the strength of the joined portion of the holding body and the cylindrical support can be improved. Moreover, when the inside of a space | gap is a non-vacuum state, it is preferable that inert gas, such as nitrogen gas and argon gas, exists mainly. At this time, the air pressure in the gap is preferably maintained at a reduced pressure lower than atmospheric pressure at room temperature. Even if it does in this way, while being able to provide high heat insulation performance, the strength reduction of a junction part can be avoided.

  The cylindrical support has through holes that open at both end faces. In the through hole, for example, a terminal electrode for supplying power to a resistance heating element embedded in the holding body, a thermocouple for temperature measurement, a lift pin for lifting the substrate to be processed, and the like are accommodated. Yes. Here, when the void and the through hole are projected onto a virtual plane parallel to the main surface, the void may be formed so as to surround the through hole on the projection surface. By arranging the gaps in this way, heat insulation is evenly provided around the through-holes, leading to an improvement in the in-plane thermal uniformity of the holding body. In addition, the space | gap and the through-hole may exist in the same surface, and may exist in a mutually different surface.

  The space | gap is ring shape and may surround the through-hole over the perimeter. With this configuration, since the voids are continuously arranged around the through-hole, the in-plane thermal uniformity of the holding body can be improved. Moreover, the space | gap is a ring shape divided | segmented in multiple places, Comprising: The through-hole may be surrounded discontinuously. With this configuration, not only heat insulation can be achieved evenly around the through-holes, but also a decrease in strength of the joint portion can be avoided.

  Here, when the cylindrical support body which has a through-hole, and a holding body are joined, a junction part turns into an annular | circular shaped area | region. The concave portion forming the gap may be arranged at any position in the annular region as long as it can be an airtight gap isolated from the outside. Preferably, the concave portion is arranged at a position slightly separated from the inner circumference and the outer circumference of the annular region (for example, a position separated from each other by 5 mm or more). Furthermore, if the distance from the inner periphery to the outer periphery of the annular region is defined as the width of the annular region (that is, the width of the joint portion), the width of the concave portion is preferably about 10% to 50% of the width of the joint portion. Is preferably set to about 30% to 40%. The reason is that while the in-plane thermal uniformity of the holding body can be reliably improved, the strength reduction of the joint portion can be surely avoided. In this case, the concave portion is not disposed in the vicinity of the inner periphery or the outer periphery of the annular region, but may be disposed at an intermediate position where the distances from the inner periphery and the outer periphery are equal. With this configuration, the distance to reach the inner and outer circumferences of the annular region is relatively long, so that an airtight gap can be reliably formed. Further, the depth of the recess is not particularly limited and is arbitrarily set. For example, the depth is preferably 1 mm or more, and more preferably 3 mm or more. The reason is that if it is shallower than 1 mm, it is difficult to provide suitable heat insulation performance. However, if the recess is too deep, the mechanical strength of the cylindrical support or the holding body may be lowered. Therefore, the depth of the recess is preferably 10 mm or less, and more preferably 5 mm or more. Good.

  Moreover, as another means (means 2) for solving the above-mentioned problem, there is provided a method for manufacturing the apparatus according to the above means 1, wherein the holding body and the cylindrical support body are prepared, and the holding body is provided. A preparation step of forming a recess to be the gap later on at least one of the back surface and the end surface of the cylindrical support, and the back surface of the holding body and the end surface of the cylindrical support. And a bonding step of bonding the holding body and the cylindrical support body by pressing the holding body and the cylindrical support body in a vacuum or a reduced pressure atmosphere. There is a device manufacturing method.

  Therefore, according to the method described in the means 2, the holding body and the end face of the cylindrical support body are overlapped with each other through a joining step of pressing the holding body and the cylindrical support body. The cylindrical support is joined. At this time, since the holding body and the cylindrical support body are bonded in a vacuum or in a reduced pressure atmosphere, in addition to being able to bond both together firmly, an airtight gap isolated from the outside can be easily and reliably obtained. Can be formed. Furthermore, according to this method, the resistance heating element becomes difficult to be oxidized, so that it is possible to prevent deterioration of the resistance heating element and variation in resistance value. And even if it is a case where the support body and cylindrical support body made from a non-oxide ceramic are selected, they can be reliably joined.

  Both the holding body and the cylindrical support prepared through the preparation process are ceramic sintered bodies. These ceramic sintered bodies are obtained by first producing a ceramic molded body using a ceramic material and then firing the molded body. A concave portion that becomes a void later can be processed and formed before and after firing.

  In the joining step, it is preferable that the back surface of the holding body, which is the joining surface, and the end surface of the cylindrical support body are smoothed in advance by polishing and then overlapped with each other. The reason for this is that by joining smooth joint surfaces having a small surface roughness, the adhesion between the joint surfaces can be improved and a highly airtight void can be reliably formed. In this case, the surface roughness (Ra) of the bonding surface is, for example, preferably 2 μm or less, and more preferably 1 μm or less. Further, the flatness of the joint surface is preferably 15 μm or less, and more preferably 10 μm or less.

  In the joining step, the holding body and the cylindrical support are pressed in a vacuum or a reduced pressure atmosphere. At this time, a known bonding agent including, for example, a sintering aid is applied to the bonding surfaces in advance, and then the holding body and the cylindrical support are bonded by performing a heat treatment in a state where a load is applied by a press. .

The schematic sectional drawing which shows the heating apparatus (susceptor) for the semiconductor manufacturing apparatus of Example 1 in embodiment which actualized this invention. Sectional drawing in the AA of the heating apparatus of FIG. The figure for demonstrating the manufacturing procedure of the heating apparatus of Example 1. FIG. Sectional drawing in the AA of the heating apparatus of Example 2. FIG. Sectional drawing in the AA of the heating apparatus of Example 3. FIG. Sectional drawing in the AA of the heating apparatus of the comparative example 2. FIG. The principal part expanded sectional view which shows the space | gap in the heating apparatus of another embodiment. The principal part expanded sectional view which shows the space | gap in the heating apparatus of another embodiment. The principal part expanded sectional view which shows the space | gap in the heating apparatus of another embodiment. The principal part expanded sectional view which shows the space | gap in the heating apparatus of another embodiment.

  Hereinafter, an embodiment in which the present invention is embodied in a heating apparatus (susceptor) for a semiconductor manufacturing apparatus will be described in detail with reference to FIGS.

  As shown in FIGS. 1 and 2, the heating device 11 for a semiconductor manufacturing apparatus according to the present embodiment is a susceptor for heating to a predetermined processing temperature while holding a semiconductor wafer 15 as a substrate to be processed. is there. The heating device 11 basically includes a ceramic holder 21 and a ceramic cylindrical support 31.

  The holding body 21 of the present embodiment is a plate-like object having a substantially circular shape in a plan view having a diameter of about 100 mm to 500 mm and a thickness of about 3.0 mm to 10.0 mm. The holding body 21 has a flat main surface 22 which is a holding surface for holding the semiconductor wafer 15 and a flat back surface 23 which is a bonding surface on the holding body side. The holding body 21 is made of a dense ceramic sintered body and has a structure in which a plurality of ceramic layers (not shown) are laminated. Note that the holding body 21 of the present embodiment is made of aluminum nitride.

  As shown in FIGS. 1 and 2, the cylindrical support 31 of the present embodiment is a hollow cylindrical member having a through hole 34 that opens at an upper end surface 32 and a lower end surface 33. The cylindrical support 31 has an outer diameter of about 30 mm to 90 mm, an inner diameter of about 10 mm to 60 mm, and a length of about 100 mm to 300 mm. The cylindrical support 31 is made of a dense ceramic sintered body, and is made of aluminum nitride in the present embodiment, like the holding body 21. The end surface 32 which is a joining surface on the cylindrical support side is joined and fixed to the central portion of the back surface 23 of the holding body 21 via a joining layer (not shown) mainly composed of a sintering aid component.

  As shown in FIG. 1, a resistance heating element 25 as a heater electrode layer for heating the entire holding body 21 is embedded at a predetermined depth position in the holding body 21. The resistance heating element 25 is a conductor layer formed of a refractory metal such as tungsten or molybdenum as a main component, and in the present embodiment, the resistance heating element 25 is laid out so as to be concentric and drawn with one stroke. Two end portions of the resistance heating element 25 are provided in the vicinity of the central portion of the holding body 21, and one end portion of the via conductor 26 is connected to these portions. On the other hand, a pair of power receiving electrodes 27 is provided on the back surface 23 of the holding body 21, and the other end of the via conductor 26 is connected to them. As a result, the resistance heating element 25 and the power receiving electrode 27 are electrically connected via the via conductor 26. On the surface of these power receiving electrodes 27, rod-shaped electrode terminals 43 accommodated in the through holes 34 of the cylindrical support 31 are joined by brazing. By applying a voltage to these electrode terminals 43, electric power is supplied to the resistance heating element 25 embedded in the holding body 21, and the temperature of the holding body 21 is increased. Further, a thermocouple 42 is accommodated in the through hole 34 of the cylindrical support 31, and a tip end portion 44 of the thermocouple 42 is embedded in the central portion of the holding body 21.

  As shown in FIG. 1 and FIG. 2, an airtight gap 41 isolated from the outside is formed in the joint portion B <b> 1 between the holding body 21 and the cylindrical support body 31. The space 41 is in a vacuum state in which almost no gas exists. The gap 41 serves to block a part of the heat escape path from the holding body 21 to the cylindrical support 31. The gap 41 is formed by a recess 36 formed in the end surface 32 of the cylindrical support 31 and is formed in a ring shape that continuously surrounds the through hole 34 over the entire circumference. The recessed part 36 of this embodiment is an annular groove, and is disposed at a position 3 mm or more away from the inner periphery and outer periphery of the annular region. In the present embodiment, the width W1 of the joint portion B1 is 10 mm, and the width W2 of the recess 36 is set to about 30% to 40% of the width W1 of the joint portion B1. Specifically, the width W2 of the recess 36 is set to about 3 mm to 4 mm. Moreover, the recessed part 36 is a cross-sectional rectangular shape, The depth is set to about 3 mm-5 mm.

  Hereinafter, the manufacturing procedure of the heating apparatus 11 of Example 1 of this embodiment will be described with reference to FIG.

(Preparation of holder 21)
An organic solvent such as toluene is added to a mixture of 100 parts by weight of aluminum nitride powder, 1 part by weight of yttrium oxide (yttria; Y ₂ O ₃ ) powder, 20 parts by weight of an acrylic binder, and an appropriate amount of dispersant and plasticizer. And mixed for 24 hours with a ball mill to prepare a slurry for green sheets. Then, using this slurry as a starting material, the slurry was formed into a sheet shape with a casting apparatus and then dried to produce a plurality of green sheets 51 having a thickness of about 350 mm and a thickness of 0.8 mm.

  Further, a metallized paste was prepared by adding and kneading conductive powder such as tungsten or molybdenum to a mixture of organic solvents such as aluminum nitride powder, acrylic binder, and terpineol. Then, by printing this metallized paste using a screen printing device or the like, an unsintered conductor layer 52 that later becomes the resistance heating element 25, the power receiving electrode 27, or the like was formed on the specific green sheet 51. Moreover, the green conductor 51 was printed in a state in which a via hole was previously provided, thereby forming an unsintered conductor portion that later became the via conductor 26. If it is necessary to form an electrostatic chuck electrode or an RF electrode, an unsintered conductor layer that will later become these electrodes may be further formed. Moreover, you may form various holes (For example, the hole for thermocouple fixation, the hole for lift pin protrusion, etc.) as needed.

  Next, a plurality of these green sheets 51 (for example, 20 sheets in the present embodiment) were subjected to thermocompression bonding, and the outer periphery was cut as necessary to produce a green sheet laminate having a thickness of about 8 mm. Subsequently, the green sheet laminate was cut by machining to produce a disk-shaped molded body 53. Next, the obtained molded body 53 was degreased in nitrogen at 550 ° C. for 12 hours to obtain a degreased body. Further, this degreased body was put in an aluminum nitride sheath of the carbon furnace K1, and fired at 1900 ° C. for 4 hours in a nitrogen atmosphere and at normal pressure to produce a fired body 54. Further, the surface of the fired body 54 was polished to produce the holding body 21 having a target dimension (diameter 330 mm × thickness 5 mm).

(Preparation of cylindrical support 31)
An organic solvent such as methanol is added to a mixture of 100 parts by weight of aluminum nitride powder, 1 part by weight of yttrium oxide powder, 3 parts by weight of PVA binder, and appropriate amounts of a dispersant and a plasticizer, and mixed for 15 hours in a ball mill. did. The slurry thus obtained was granulated with a spray dryer and used as a raw material powder. Next, the raw material powder was filled in a state where the core 62 was disposed at the center of the rubber mold 61, and cold isostatic pressing was performed at a pressure of 200 MPa. As a result, a cylindrical molded body 63 having a through hole 34 and a recess 36 that later forms a void 41 was obtained. Here, a rubber mold 61 having an annular convex portion 64 for forming a concave portion on the inner surface was used, and the concave portion 36 was formed simultaneously with press molding. Instead of this method, the recess 36 may be formed by machining by press-molding.

  The obtained molded body 63 was vertically defatted at 600 ° C. in the air to obtain a defatted body. Further, this degreased body was suspended in a firing furnace K2 in a nitrogen gas atmosphere and fired at 1850 ° C. for 5 hours. As a result, a fired body 67 (that is, the cylindrical support 31) having an outer diameter of 60 mm, an inner diameter of 40 mm, and a length of 200 mm was obtained.

(Joining of the holding body 21 and the cylindrical support body 31)
After performing the preparatory process as described above, the bonding process was performed according to the following procedure. In the joining step, first, lapping was performed on the joining surface (that is, the back surface 23) of the holding body 21 and the joining surface (that is, the end surface 32) of the cylindrical support 31. In this lapping process, the surface roughness Ra was 1 μm or less and the flatness was 10 μm or less. A known bonding agent mixed with a rare earth, an organic solvent, or the like was uniformly applied to the bonding surface of the holder 21 or the cylindrical support 31, and then degreased. Next, the back surface 23 of the holding body 21 and the end surface 32 of the cylindrical support 31 are overlapped, and the temperature is 1400 ° C. to 1850 ° C. in an inert gas such as nitrogen gas or argon gas, or in a vacuum. Hot press firing was performed at a pressure of 0.5 MPa to 10 MPa. Here, hot press firing is performed in vacuum at a temperature condition of 1600 ° C. while applying a press pressure P1 of 1 MPa in the axial direction of the cylindrical support 31 using the firing furnace K3 for hot press. The cylindrical support 31 was joined.

(Junction of electrode terminal 43, etc.)
After the joining step, the rod-shaped electrode terminal 43 was brazed on the surface of the power receiving electrode 27, and the tip portion 44 of the thermocouple 42 was embedded and fixed in the thermocouple fixing hole in the holding body 21. Through the above steps, the heating apparatus 11 of Example 1 shown in FIG. 1 was completed.

  Then, a heating device 11A (see FIG. 4) in Example 2, a heating device 11B in Example 3 (see FIG. 5), and a heating device 100 in Comparative Example 2 (see FIG. 6) were produced in the same procedure. When Example 1 is compared with Examples 2 and 3, the shapes of the air gaps 41, 41A, and 41B are different from each other. For example, the gap 41 </ b> A of the second embodiment is formed by a plurality of circular recesses 71 (diameter 3 mm to 4 mm) arranged in a ring shape so as to surround the through hole 34. Accordingly, the through hole 34 is discontinuously surrounded by the plurality of gaps 41A. The air gap 41 </ b> B of the third embodiment is formed by a plurality of concave portions 72 arranged in a ring shape so as to surround the through hole 34. These concave portions 72 are substantially the same as those obtained by equally dividing the concave portion 36 of Example 1 at a plurality of locations (eight locations). Accordingly, the through hole 34 is discontinuously surrounded by the plurality of gaps 41B. On the other hand, Comparative Example 2 includes the same gap 41 as that of Example 1. However, in the heating apparatus 100 of the comparative example 2, two gas supply paths 101 opened in the gap 41 are formed, and the gap 41 is connected to the outside through the gas supply paths 101. Then, nitrogen gas can be allowed to flow into the gap 41 through these gas supply paths 101. In addition, although not particularly illustrated, a case where no void was formed was positioned as Comparative Example 1.

The following evaluation tests were conducted for each of the above examples and comparative examples. That is, a DC voltage of 200 V was applied to the resistance heating element 25 in a vacuum, and the main surface 22 side of the holding body 21 was heated to a set temperature (T ₀ = 450 ° C.). The temperature of the main surface 22 at that time was measured with an infrared thermography apparatus. And the location where the temperature is the highest in the main surface 22 and the location where the temperature is the lowest among the areas directly above the joint portion B1 with the cylindrical support 31 are selected, and the temperatures of both are compared. The results are shown in Table 1. Incidentally, Table 1 shows “maximum in-plane temperature T _max (° C.)”, “minimum temperature T _min (° C.) immediately above the junction”, “temperature difference T _max −T _min (° C.)”, “setting”. temperature difference with respect to the temperature _{T 0} (percent) "described. “Temperature difference (%) with respect to set temperature T ₀ ” indicates whether the in-plane heat uniformity is good or bad.

As a result, in Examples 1 to 3, the in-plane thermal uniformity could be within ± 1.0%, and in Example 1, in particular, within ± 0.5%. On the other hand, in Comparative Example 1 in which no void was formed, the effect of so-called heat escape was large, and the in-plane thermal uniformity could not be made within ± 1.0%. Further, in Comparative Example 2, since the heat was taken away from the gas supply path 101 even though the gap 41 was formed, the in-plane thermal uniformity could not be made within ± 1.0%.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the heating devices 11, 11A, and 11B of the present embodiment, airtight gaps 41, 41A, and 41B that are isolated from the outside exist in the joint portion B1 between the holding body 21 and the cylindrical support body 31. The part has a heat insulating structure. As a result, the cross-sectional area of the heat escape path from the holding body 21 to the cylindrical support 31 is reduced, and the in-plane heat uniformity of the main surface 22 of the holding body 21 is improved. Therefore, according to the heating devices 11, 11A, and 11B of the present embodiment, the semiconductor wafer 15 can be uniformly heat-treated, and an improvement in yield during semiconductor manufacturing can be achieved.

  (2) According to the manufacturing method of the present embodiment, the holding body 21 and the cylindrical shape are obtained by performing a joining step in which the back surface 23 of the holding body 21 and the end surface 32 of the cylindrical support body 31 are superposed and subjected to hot press firing. The support 31 is joined. At this time, since the holding body 21 and the cylindrical support 31 are bonded in a vacuum or in a reduced pressure atmosphere, both can be firmly bonded. In addition, the airtight gaps 41, 41A, 41B isolated from the outside can be easily and reliably formed. Further, according to this method, the resistance heating element 25 is hardly oxidized, so that it is possible to prevent deterioration of the resistance heating element 25 and variations in resistance values. And even if it is a case where the support body 21 and the cylindrical support body 31 made of aluminum nitride which are non-oxide ceramics are selected, they can be prevented from being oxidized and deteriorated during the joining process. Bonding can be performed reliably.

  In addition, you may change embodiment of this invention as follows.

  -You may form the space | gap 41C by the recessed part 36A provided in the back surface 23 of the holding body 21 like the heating apparatus 11C of another embodiment shown in FIG. Further, like the heating device 11D of another embodiment shown in FIG. 8, the gap 41D is formed by the recess 36B provided on the back surface 23 of the holding body 21 and the recess 36C provided on the end surface 32 of the cylindrical support 31. It may be formed.

  In the above embodiment, the gap 41 is formed by providing the recess 36 having a rectangular cross section on the end face 32, but the recess cross-sectional shape is not limited to this. For example, like the heating device 11E of another embodiment shown in FIG. 9, the gap 41E may be formed by providing the end surface 32 with a recess 36D having an isosceles cross section. Or you may form the space | gap 41F by providing the recessed part 36E of cross-sectional semicircle shape in the end surface 32 like the heating apparatus 11F of another embodiment shown in FIG.

  In the above embodiment, both the holding body 21 and the cylindrical support body 31 are made of aluminum nitride, but the invention is not limited to this. For example, both may be made of alumina. In addition to using the same type of ceramic as described above, the holding body 21 and the cylindrical support 31 may be configured by combining different types of ceramics. For example, the holding body 21 may be made of aluminum nitride, and the cylindrical support 31 may be made of alumina having a lower thermal conductivity.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiments described above are listed below.

(1) In the above means 1 and 2, the pressure of the gas in the gap is lower than atmospheric pressure at room temperature.
(2) In the above means 1 and 2, the gas in the gap is mainly composed of an inert gas.
(3) In the above means 1 and 2, the holding body and the cylindrical support are both made of nitride ceramic.
(4) In the above means 1 and 2, the width of the concave portion is set to 30% to 40% of the width of the joint portion.
(5) In the above means 1 and 2, the depth of the gap is 3 mm to 5 mm.

DESCRIPTION OF SYMBOLS 11, 11A, 11B, 11C, 11D, 11E, 11F ... Heating device 15 ... Semiconductor wafer 21 as a to-be-processed base material 21 ... Holding body 22 ... Main surface 23 ... Back surface 25 ... Resistance heating element 31 ... Cylindrical support body 32 ... End face 34 ... Through hole 36,36A, 36B, 36C, 36D, 36E ... Recess 41,41A, 41B, 41C, 41D, 41E, 41F ... Gap B1 ... Junction part

Claims (6)

A ceramic holder having a main surface and a back surface on which the substrate to be treated is placed, and a resistance heating element embedded therein;
A ceramic cylindrical support whose end face is joined to the back surface;
A heating apparatus, wherein an airtight gap isolated from the outside is formed at a joint portion between the holding body and the cylindrical support body.   The heating device according to claim 1, wherein the gap is formed by a recess provided in the end face of the cylindrical support. The cylindrical support has a through hole that opens at the end face;
3. The projection according to claim 1, wherein the gap is formed so as to surround the through hole on a projection plane obtained by projecting the gap and the through hole onto a virtual plane parallel to the main surface. Heating device.   The heating apparatus according to claim 3, wherein, in the projection surface, the gap is ring-shaped and surrounds the through hole over the entire circumference.   4. The heating apparatus according to claim 3, wherein, on the projection surface, the gap is a ring shape divided at a plurality of locations and surrounds the through hole discontinuously. A method for manufacturing an apparatus according to any one of claims 1 to 5,
A preparing step of preparing the holding body and the cylindrical support, and forming a recess that will later become the gap on at least one of the back surface of the holding body and the end surface of the cylindrical support; ,
The back surface of the holding body and the end surface of the cylindrical support body are overlapped, and the holding body and the cylindrical support body are pressed in a vacuum or a reduced pressure atmosphere by pressing the holding body and the cylindrical support body. The manufacturing method of the heating apparatus characterized by including the joining process which joins a body.