JP4776157B2 - Ceramic heater - Google Patents

Description

The present invention is mainly related to the ceramic heater for use in heating the wafer, for example, to form a thin film on a semiconductor wafer or a liquid crystal device or on a wafer such as a circuit board, drying the resist solution applied on the wafer baked to about the preferred ceramic heater in or form a resist film.

  2. Description of the Related Art A heater for heating a semiconductor wafer (hereinafter abbreviated as a wafer) is used 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.

  Ceramic heaters are widely used in accordance with demands for excellent temperature controllability, miniaturization of semiconductor element wiring, and improvement of wafer heat treatment temperature accuracy.

  As such a ceramic heater, for example, Patent Document 1, Patent Document 2, Patent Document 3 and Patent Document 4 propose a ceramic heater 71 as shown in FIG.

  This ceramic heater 71 has a plate-like ceramic body 72 and a case 79 as main components, and is made of nitride ceramics or carbide ceramics at the opening of a bottomed case 79 made of metal such as aluminum. The plate-like ceramic body 72 is fixed with bolts 80 via a resin heat-insulating connection member 74, and the upper surface thereof is used as a mounting surface 73 on which the wafer W is placed. As shown in FIG. 8, a concentric resistance heating element 75 is provided.

  Furthermore, a power supply terminal 77 is brazed to the terminal portion of the resistance heating element 75, and the power supply terminal 77 is inserted into a lead wire drawing hole 76 formed in the bottom 79 a of the case 79. And was to be electrically connected.

  Then, the refrigerant is sent from the nozzle 82 into the space surrounded by the plate-like ceramic body 72 and the case, circulated, and discharged from the discharge port 83 to cool the plate-like ceramic body 72.

Incidentally, in such a ceramic heater 71, or to form a uniform film over the entire surface of the wafer W, or to homogenize the heating reaction conditions of the resist film to reduce the temperature difference within the wafer temperature distribution It is important to make the temperature uniform, and at the same time, the transient time when heating and cooling the wafer is short, and the temperature during the transient is required to be uniform. Furthermore, it is necessary to change the set temperature of the ceramic heater 71 in order to change the heating temperature of the wafer, the time or heated or cooled ceramic heater 71 in a short time there was a short required.

In Patent Document 5, as shown in FIG. 7, if the surface roughness of the bottom 79 a of the case 79 is set to a certain value or less, the airflow is not disturbed at the interface with the bottom 79 a , and the heating efficiency and cooling efficiency are reduced . or improving, is increased and the temperature rise efficiency reflection of heat rays has been described that you or improved.

  In Patent Document 6, the heating capacity and cooling rate of the wafer are increased by setting the heat capacity of the ceramic heater 71 to 5000 J / K or less. However, the heat capacity of the case 79 is as large as 3.3 times the heat capacity of the plate-like ceramic body 73, and the ratio S / V between the surface area S of the case 79 and the volume V of the case 79 is 5 (1 / cm). The cooling time was long because it was lower.

  However, in all cases, the time for changing the set heating temperature of the wafer is long, and a ceramic heater capable of changing the temperature in a short time has been demanded.

Incidentally, in such a ceramic heater 71, whole or to form a uniform film surface U E wafer W, to or homogenize the heating reaction conditions of the resist film, the temperature distribution of the c E c uniform It is important to make it. Therefore, to reduce the temperature distribution of the c E c far, to adjust the resistance distribution of the strip-shaped resistance heating element 75, it has been carried out or to divide control the temperature of the strip of the resistance heating element 75 In addition, in the case of a structure that easily generates heat, a proposal has been made to increase the amount of heat generation around the structure.

However, there is a problem that both require a very complicated structure and control, and there is a demand for a ceramic heater that can uniformly heat the temperature distribution with a simple structure.
JP 2001-135684 A JP 2001-203156 A JP 2001-313249 A JP 2002-76102 A JP 2002-83848 A JP 2002-100462 A JP 2002-64133 A

  In chemically amplified resists that have begun to be used in connection with the miniaturization of wiring of semiconductor elements, not only the uniformity of the temperature of the wafer but also the transition from the moment the wafer is placed on the heat treatment apparatus to the end of the heat treatment. Such a temperature history is also extremely important, and it is desired that the temperature of the wafer be stabilized uniformly within about 60 seconds immediately after the wafer is placed.

In particular, the temperature upon replacing the U E wafer W on the plate-shaped ceramic member 72 has a problem with the temperature variations in time and c E c plane to be stabilized is large.

  However, the ceramic heater introduced in Patent Document 7 is composed of a plate-like ceramic body made of aluminum nitride having a diameter of 210 mm and a case of 0.35-0.81 kg and its accessories 0.43-2.91 kg. Yes. Moreover, it comprised from 0.73-1.51kg case and its accessory 0.77-6.29kg to the aluminum nitride of diameter 320mm. However, these ceramic heaters have a problem that a rapid temperature rise and cooling time of the wafer is long and insufficient, and a transient temperature difference in the wafer surface is large.

Further, in the ceramic heater described in Patent Document 5, in order to circulate and cool the coolant in the space surrounded by the plate-like ceramic body 73 and the case 79 shown in FIG. 7, the surface roughness Ra of the bottom surface 79a of the case 79 is 20 μm. Although a larger follows cooled efficiently eliminate turbulence of the airflow, a limited range of flow of the air flow from the nozzle 82, since only partially cooled, the wafer, only be efficiently cooled for example, the center temperature I had problems with being cooled at a temperature difference is large state of the wafer surface even.

  Furthermore, the ceramic heater described in Patent Document 6 has a heat capacity of 5000 J / K or less to improve temperature rise characteristics and cooling characteristics, but has a problem that a temperature difference in the wafer surface is large.

The ceramic heater according to the present invention includes a heater unit having a resistance heating element on one main surface of a plate-like ceramic body mainly composed of aluminum nitride or silicon carbide, and a wafer heating surface on the other main surface, and the resistance A power supply terminal for supplying power to the heating element, a bottomed case connected to the plate-shaped ceramic body so as to wrap the power supply terminal, and a peripheral portion of the plate-shaped ceramic body supported in a ring shape and connected to the case A contact member and a non-heat generation area where the resistance heating element does not exist are provided outside the circumscribed circle of the resistance heating element around the plate-like ceramic body, and a gas for cooling the plate-like ceramic body is ejected to the case and a nozzle, infrared absorptivity of the inner surface of the case is 30% or less, the thickness of the non-heat generating area to wherein a greater thickness of the central portion of the plate-shaped ceramic .

The infrared absorption of the inner surface of the front SL case being smaller than the absorption rate of infrared its outer surface.

The front SL case is made of metal, Cr in mass%: 17~26%, Ni: 8~22 %, C: 0.2% or less, N: 0.1% or less, and the balance of Fe and inevitable components It is characterized by becoming.

The surface roughness Ra of the front SL case, characterized in that it is 5μm or less.

Also characterized in that the formation of the absorption layer of the infrared to the outer surface of the front SL case.

The front Symbol reflective layer is characterized in that it is a noble metal layer such as Ag, Cu or Au.

The front Symbol plate-shaped ceramic body before Symbol contact member in a ring shape so as to support the lower surface of the periphery of which is characterized in that connected.

The front Symbol plate-shaped ceramic member the contact member so as to surround the end surface of the periphery of which is characterized in that connected.

  The diameter of the circumscribed circle of the resistance heating element is 90 to 99% of the diameter of the plate-like ceramic body.

  The diameter of the circumscribed circle of the resistance heating element is 92 to 95% of the diameter of the plate-like ceramic body.

  The diameter of the circumscribed circle of the resistance heating element is 95 to 98% of the diameter of the plate-like ceramic body.

The heat capacity of the case is 0.5 to 3.0 times the heat capacity of the plate-like ceramic body.

Further, the surface area S (cm of the case) ² ) And volume V (cm) of the case ³ ) And the ratio S / V is 5 to 50 (1 / cm).

  Further, the opposing spacing S of the resistance heating elements is not more than 5 times the thickness of the plate-like ceramic body.

  The thickness of the plate-like ceramic body is 1 to 7 mm, and the ratio of the area of the resistance heating element to the area of the circumscribed circle of the resistance heating element is 5 to 50%.

  Moreover, the width | variety with which the said contact member contacts the said plate-shaped ceramic body is 0.1-13 mm, It is characterized by the above-mentioned.

  Further, the thermal conductivity of the contact member is smaller than the thermal conductivity of the plate-like ceramic body.

  The contact member has a Young's modulus of 1 GPa or more and is smaller than that of the plate-like ceramic body.

  The contact member may have a circular cross section.

  The diameter of the contact member is 1 mm or less.

According to the present invention, a heater unit having a resistance heating element on one main surface of a plate-like ceramic body mainly composed of aluminum nitride or silicon carbide and a wafer heating surface on the other main surface; A power supply terminal for supplying power to the body, a bottomed case connected to the plate-like ceramic body so as to wrap the power supply terminal, and a contact for supporting the periphery of the plate-like ceramic body in a ring shape and connecting to the case A nozzle that ejects a gas for cooling the plate-shaped ceramic body to the case by providing a non-heat-generating region where the resistance heat-generating body does not exist outside the circumscribed circle of the resistance heat generating body around the member and the plate-shaped ceramic body with the door, the infrared absorptivity of the inner surface of the case is 30% or less, by the thickness of the non-heat generating area larger than the thickness of the central portion of the plate-shaped ceramic, within the wafer In degrees difference small yet small response time, a small good ceramic heater of the temperature difference within the wafer during the transient is obtained.

  Embodiments of the present invention will be described below.

  FIG. 1 is a cross-sectional view showing an example of a ceramic heater 1 according to the present invention, in which one main surface of a plate-like ceramic body 2 made of ceramics mainly composed of silicon carbide or aluminum nitride is a wafer heating surface on which a wafer W is placed. 3 and a heater portion 30 having a resistance heating element 5 formed on the other main surface.

  The pattern shape of the resistance heating element 5 may be any pattern shape that can heat the wafer heating surface 3 uniformly, such as a substantially concentric shape or a spiral shape. In order to improve the thermal uniformity, the resistance heating element 5 can be divided into a plurality of patterns. Further, the line width and density of the pattern may be adjusted to improve the soaking property by distributing the power density.

The resistance heating element 5 is formed with a power feeding portion 6 made of a material such as gold, silver, palladium, platinum or the like, and the power feeding terminal 11 is brought into contact with the power feeding portion 6 to ensure conduction. A feeding terminal 11 and the power supply unit 6, if there in a way that conduction can be ensured, soldering, or using a technique b c with like.

  Further, the bolt 16 is passed through the outer periphery of the opening of the plate-shaped ceramic body 2 and the bottomed case 19, and a ring-shaped contact member 17 is interposed so that the plate-shaped ceramic body 2 and the bottomed case 19 do not directly contact each other. Then, the nut 20 is screwed in via the elastic body 18 from the bottomed case 19 side and is elastically fixed.

Thereby, even if the bottomed case 19 is deformed when the temperature of the plate-like ceramic body 2 fluctuates, the elastic body 18 absorbs this, thereby suppressing the warpage of the plate-like ceramic body 2 and the wafer. It is possible to prevent the occurrence of temperature variations due to warpage of the plate-like ceramic body 2 on the surface.

  The bottomed case 19 has a side wall portion 22 and a bottom surface 21, and the plate-like ceramic body 2 is installed so as to cover the opening of the bottomed case 19. In addition, the bottomed case 19 is provided with a discharge port 23 for discharging cooling gas, and a power supply terminal for conducting electricity to the power supply unit 6 for supplying power to the resistance heating element 5 of the plate-like ceramic body 2. 11. A gas injection port 24 for cooling the plate-like ceramic body 2 and a thermocouple 27 for measuring the temperature of the plate-like ceramic body 2 are provided.

  Furthermore, it is desirable that the bottomed case 19 has a depth of 10 to 50 mm, and the bottom surface 21 is installed at a distance of 10 to 50 mm from the plate-like ceramic body 2. More preferably, it is 20-30 mm. This is because the wafer heating surface 3 is heated by the radiant heat between the plate-shaped ceramic body 2 and the bottomed case 19, and at the same time, there is a heat insulation effect from the outside of the case 19, so the temperature distribution on the wafer heating surface 3 is large. It is because it affects.

  Further, the plate-like ceramic body 2 is provided with at least three through holes 26, and by moving the wafer lift pins 25 up and down, the wafer can be quickly placed and removed from the plate-like ceramic body 2. The guide member 10 is installed so that the wafer lift pins 25 do not directly contact the plate-like ceramic body 2.

  The ceramic heater 1 of the present invention is characterized in that the infrared absorption rate of the inner surface of the case 19 is 30% or less. With such a configuration, it is possible to prevent the radiant heat from the plate-like ceramic body 2 heated by the resistance heating element 5 from being absorbed by the inner wall of the case 19 to heat the case 19 itself and to reflect from the case 19. It is because the radiant heat which heated the lower surface of the plate-shaped body and can heat the plate-shaped ceramic body 2 uniformly. In particular, when the temperature of the plate-like ceramic body 2 is 100 ° C. or higher, the radiant heat of a wavelength of 5 to 9 μm in the infrared region increases from the lower surface of the resistance heating element 2 of the plate-like ceramic body 2 and the reflected heat from the inner surface of the case 19 increases. If the influence of the infrared ray absorption on the inner surface of the case 19 is 30% or less, the heating of the case 19 is suppressed, and the heating of the plate-like ceramic body 2 is promoted by the reflected wave from the case 19, and the plate-like ceramic body This is because the effect of reducing the temperature difference between the two wafer heating surfaces 3 is enhanced. In particular, the case 19 is irradiated with radiation waves radiated from the plate-shaped ceramic body and absorbed, and the case 19 is heated. Among these radiated waves, the case 19 mainly has an infrared region having a wavelength of about 3 to 15 μm. Heat.

  On the other hand, the plate-like ceramic body 2 mainly composed of aluminum nitride or silicon carbide used in the present invention is preferably a carbide or nitride ceramic having a thermal conductivity of 100 W / (m · K) or more. It is considered that the radiation wave of the plate-like ceramic body 2 heated to around 200 ° C. suddenly increases from a wavelength of about 4 μm and rapidly decreases from a wavelength of about 10 μm, and the case 19 substantially emits far-infrared radiation having a wavelength of 4 to 10 μm. It is assumed that the case 19 is heated by the waves. For this reason, the absorptance of far infrared rays having a wavelength of 4 to 10 μm is important, and particularly the absorptance to radiation of 6 to 8 μm is important. Can be substituted.

  In particular, it has been found that this effect is great in the plate-like ceramic body 2 mainly composed of nitride or carbide ceramics such as aluminum nitride or silicon carbide. More specifically, it is preferable that the far-infrared absorptivity with a wavelength of 7 μm is 30% or less as a value representative of the far-infrared absorptivity.

The plate-like ceramic body 2 is provided with a resistance heating element 5 so as to uniformly heat the wafer W, but the wafer W placed on the wafer heating surface 3 is in a state where the temperature difference in the wafer W surface is small. or is rapidly heated, the or Tsu line in a short time the temperature change of the wafer heating surface 3, the plate-shaped ceramic body 2 while heating the plate-shaped ceramic body 2 as plane temperature difference of the wafer W is reduced Heat transmitted from the periphery of the case 19 to the case 19 covering the lower surface, heat transmitted from the upper part of the outer periphery of the case 19 to the periphery of the plate-like ceramic body 2 through the contact member 17, and radiant heat for heating the plate-like ceramic body 2 from the inner surface of the case 19 It is important to effectively suppress / control the influence. The radiant heat reflected from the case 19 heats the lower surface of the plate-like ceramic body 2 and suppresses the heating of the case 19 itself so that the peripheral portion of the plate-like ceramic body 2 is ringed so that the temperature difference around the wafer W does not increase. It is important to have a configuration including a contact member 17 that is supported in a shape and connected to the case 19. By adopting such a configuration, for example, the temperature difference between the peripheral portions of a large wafer W having a diameter of 200 mm or more or a diameter of 300 mm or more can be kept small, and when the low-temperature wafer W is placed on the wafer heating surface 3, the wafer While supplying heat so that the temperature in the vicinity of W does not decrease from the center, the temperature of the case 19 can be suppressed when the temperature of the wafer heating surface is changed, so that the temperature can be changed quickly.

  Furthermore, it is necessary to provide a non-heat generating area where the resistance heating element 5 does not exist outside the circumscribed circle of the resistance heating element 5 around the plate-like ceramic body 2. This is because the provision of the non-heat generating region can prevent the heat from escaping from the peripheral portion of the plate-like ceramic body 2 to the case, thereby reducing the temperature difference on the wafer W surface. Further, even when the cooled wafer W is placed on the heated wafer heating surface 3 at the same time, the heat in the non-heat generating region prevents the temperature around the wafer W from being lowered, and the temperature around the wafer W and the center are heated equally. This is because the temperature of the entire surface of the wafer W rises in a state where the temperature difference in the W plane is small, and the temperature can be raised to a predetermined temperature in a short time. On the other hand, if there is no non-heat generation area and the diameter of the circumscribed circle of the resistance heating element 5 is simply increased, heat from the periphery of the plate-like ceramic body 2 in the steady state flows to the case 19 and the case 19 is heated to heat the wafer. This is because the temperature of the case 19 is high when changing the temperature of the surface and the temperature of the wafer heating surface cannot be changed in a short time.

  On the inner surface side of the case 19, a power supply terminal 11, a gas injection port 24, a gas discharge port 23, a thermocouple 27, a guide member 10, and the like are disposed. Reflection from these components is also important. In particular, since the discharge port 23 drilled in the case 19 has a large area and has an effect of reducing the amount of radiation from the inner surface of the case, the discharge port 23 is preferably disposed evenly on the lower surface of the case 19.

  The infrared absorption rate of the outer surface of the case 19 is preferably larger than the infrared absorption rate of the outer surface. The infrared ray absorption rate of the inner surface is 30% or less, and most of the heat from the plate-like ceramic body 2 can be reflected, but the absorbed radiation light heats the case 19. When the temperature of the plate-like ceramic body 2 rises, the temperature of the case 19 also rises. However, the heat of the case 19 can lower the temperature of the case 19 by radiant light from the outer surface of the case 19. When the infrared absorption rate outside the case 19 is larger than the infrared absorption rate inside, the heat heated from the inner surface of the case 19 is radiated from the outer surface of the case 19, and the temperature rise of the case 19 can be suppressed.

  The case 19 is preferably made of a metal case 19 having a small infrared absorptivity, and the infrared absorptivity can be adjusted by polishing, formation of a reflective layer, oxide film treatment, application of black paint or the like.

  Further, in the ceramic heater of the present invention, the absorption rate of infrared rays having a wavelength of 3 to 25 μm, which is important for heat transfer, affects the temperature characteristics of the ceramic heater. Among them, the influence of the absorption rate of infrared rays having a wavelength of 5 to 9 μm is large. The infrared absorptivity can be the infrared absorptivity of the present invention as an infrared absorptivity with a wavelength of 7 μm.

  The absorptance can be obtained by spectroscopic analysis.

Further, the case 19 is preferably an Fe—Cr—Ni alloy. In particular, when the Cr amount is 17 to 26% by weight, the Ni amount is 8 to 22% by weight, C is 0.2% by mass or less, and N is 0.1% by mass or less, the infrared reflectance is high, and the time Less change is preferable. More preferably, the Ni amount is 8 to 15% by weight, and more preferably the Ni amount is 8 to 16% by weight. Cr content or below 17 wt%, the Ni content you or Tsu falls below 8% by weight, the infrared absorption rate is not preferable greater than 30%. Further, Cr content is 26 wt% ultra Etari, Ni amount is not preferable to 22 wt% since the rigidity that the metal alloy to or exceeded becomes brittle large. Furthermore, C = 0.2 wt% ultra Etari, N metal alloy becomes brittle unfavorably with you or exceeded 0.1 mass%.

The surface roughness Ra of the case 19 according to JIS B0633 is preferably 5 μm or less. Ra is not preferable because a possibility that a 5μm ultra Ell and infrared absorptivity exceeds 30%. More preferably, it is 2 micrometers or less, More preferably, it is 0.5 micrometers or less.

  In order to reduce the infrared absorption rate of the case 19, it is preferable to form a reflective layer on the surface of the case 19 that does not absorb infrared rays strongly.

  The absorptive reflective layer is preferably a noble metal layer such as Ag, Cu or Au, and a plating method, a vapor deposition method or a CDV coating method can be used for these metal layers. And when these reflective layers are formed with the thickness of 0.1-5 micrometers, the absorptivity of infrared rays becomes small with 30% or less, and is preferable.

  Further, in the ceramic heater 1 of FIG. 1 which is an example of the present invention, the contact member 17 is connected in a ring shape so as to support the lower surface around the plate-like ceramic body 2. Since the diameter D of the body 2 can be made equal, the diameter of the plate-like ceramic body 2 can be increased. Therefore, even if a low-temperature wafer W is placed on a high-temperature wafer heating surface, the temperature around the wafer W does not decrease, and the heat accumulated in the non-heat-generating area around the plate-like ceramic body 2 is reduced. The surroundings can be heated.

  Further, as shown in FIG. 2, the ceramic heater 1 of the present invention is connected to the contact member 17 in a ring shape so as to surround the peripheral end surface of the plate-like ceramic body 2. Heat leakage can be prevented and the temperature difference in the wafer W surface can be reduced. Particularly, it is preferable that the peripheral end surface of the plate-like ceramic body 2 is in contact with the contact member 17 so that the diameter of the plate-like ceramic body 2 is reduced and the heat of the resistance heating element 5 can be efficiently supplied to the wafer W. Further, when a low-temperature wafer W is placed on a high-temperature wafer heating surface, it is necessary to supply a large amount of heat to the peripheral portion of the wafer W, so that a large amount of heat is stored around the plate-shaped ceramic body 2. As a region for storing this heat, a non-heat generating region in which the resistance heating element 5 does not exist is required around the plate-like ceramic body 2.

  In order to reduce the in-plane temperature difference during normal operation of the wafer W, the diameter of the circumscribed circle of the resistance heating element 5 needs to be 3 to 5% larger than the diameter of the wafer W. Therefore, the diameter D of the plate-like ceramic body 2 is preferably about 4 to 17% larger than the diameter of the wafer W. In addition, since the end surface around the plate-like ceramic body 2 is held, the non-heat-generating region of the plate-like ceramic body 2 can be reduced, while the plate-like ceramic in the non-heat-generating region in order to increase the amount of heat stored in the non-heat-generating region. By increasing the thickness of the body 2, the heat capacity of the non-heat generating region can be adjusted.

  The diameter DC of the circumscribed circle of the plate-like ceramic body 2 is more preferably 90 to 99% of the diameter D of the plate-like ceramic body 2.

The diameter DC of the circumscribed circle C of the resistance heating element 5 is less than 90% of the diameter D of the plate-shaped ceramic body 2, you or is rapidly cooled or rapidly heated wafer since the non-heat generating area is too large Time is increased and the temperature response characteristics of the wafer W are inferior. Further, the diameter D of the plate-shaped ceramic body 2 is increased, and the size of the wafer W that can be uniformly heated is smaller than the diameter D of the plate-shaped ceramic body 2, and the wafer heating efficiency with respect to the electric power for heating the wafer W is improved. Deteriorate. Furthermore, since the plate-like ceramic body 2 becomes large, the installation area of the wafer manufacturing apparatus becomes large, which is not preferable because the operating rate with respect to the installation area of the semiconductor manufacturing apparatus that needs to perform the maximum production with the minimum installation area is lowered.

  When the diameter DC of the circumscribed circle C of the resistance heating element 5 is larger than 99% of the diameter D of the plate-like ceramic body 2, the non-heat generation region is too small, and therefore when the low-temperature wafer W is placed on the high-temperature wafer heating surface 3. This is because there is a possibility that the temperature of the periphery of the wafer W is lowered and the temperature of the wafer W cannot be increased in a state where the temperature difference within the wafer W surface is small. Heat flows non-uniformly from the outer peripheral portion of the resistance heating element 5 to the contact member 17, and in particular, heat flows from a minute portion where the symmetry of the resistance heating element 5 on the outer peripheral portion is broken and missing, resulting in a decrease in temperature. However, there is a concern that the in-plane temperature difference of the wafer W during the steady state may be increased.

  More preferably, the diameter DC of the circumscribed circle C of the resistance heating element 5 is 92 to 97% of the diameter D of the plate-like ceramic body 2.

  In particular, in the case of the ceramic heater 1 of FIG. 1 in which the outer shapes of the plate-shaped ceramic body 2 and the case 19 are substantially equal and the case 19 supports the plate-shaped ceramic body 2 from below, the temperature difference in the plane of the wafer W is reduced. The diameter DC of the circumscribed circle C of the resistance heating element 5 is 92 to 95%, more preferably 93 to 95% of the diameter D of the plate-like ceramic body 2.

  On the other hand, in the case of the ceramic heater of FIG. 2 in which the case 19 is connected so as to surround the peripheral end surface of the plate-like ceramic body 2, the diameter DC of the circumscribed circle C of the resistance heating element 5 is the diameter D of the plate-like ceramic body 2. Is preferably 95 to 98%, more preferably 96 to 97%.

  In addition, the heat capacity can be adjusted by the width of the non-heated region as described above, while non-heat generation is achieved by increasing the thickness of the plate-like ceramic body 2 in the non-heat-generating region in order to increase the heat storage amount in the non-heat-generating region. It is also possible to increase the heat capacity of the region to prevent a temperature drop around the wafer W.

  In the ceramic heater 1 of the present invention, the case 19 is connected to the lower surface around the plate-like ceramic body 2 or the case is connected to the case at the peripheral end surface of the plate-like ceramic body 2. Naturally, it includes the ceramic heater 1 in a range that does not deviate from the above-mentioned meaning by connecting to the case 19 at the same time both the peripheral end faces.

  The ceramic heater 1 of the present invention is provided with a nozzle 24 for cooling the plate-like ceramic body 2 in the case 19, and the heat capacity of the case 19 is 0.5 to 3 of the heat capacity of the plate-like ceramic body 2. It is characterized by being 0 times.

  When the heat capacity of the case 19 is less than 0.5 times the heat capacity of the plate-like ceramic body 2, the cooling gas injected from the nozzle 24 hits the plate-like ceramic body 2 to remove the heat of the plate-like ceramic body 2, and Since the amount of heat stored in the case 19 is too small to appropriately store the heat of the plate-like ceramic body 2, the effect of lowering the temperature of the plate-like ceramic body 2 is small.

When the heat capacity of the case 19 obtain ultra 3.0 times the heat capacity of the plate-shaped ceramic body 2, be stored via a cooling gas into the case 19 to heat the plate-shaped ceramic member 2 from the heat capacity is too large cases 19 However, when the plate-like ceramic body 2 is heated, there is a possibility that the radiant heat from the plate-like ceramic body 2 is excessively transmitted to the case 19 and the heating rate is reduced even if the plate-like ceramic body 2 is heated. Preferably, the heat capacity of the case 19 is 0.7 to 1.2 times, more preferably 0.9 to 1.2 times that of the plate-like ceramic body 2. By setting the heat capacity within such a range, the heat of the plate-like ceramic body 2 is transmitted to the case 19 via the cooling gas injected from the nozzle 24 and efficiently discharged to the outside. Particularly, when the heat capacity of the metal case is close to the heat capacity of the plate-like ceramic body 2, approximately half of the heat of the plate-like ceramic body 2 is transferred to the metal case and dissipated from the outer surface of the metal case, so that the temperature of the plate-like ceramic body 2 is increased. I found it easy to go down. And since the heat of the heated plate-shaped ceramic body 2 can be efficiently removed, the temperature of the plate-shaped ceramic body 2 can be drastically lowered and the plate-shaped ceramic body 2 is heated by the resistance heating element 5. The temperature can be increased rapidly and efficiently.

In order to change the magnification of the heat capacity of the plate-like ceramic body 2 with respect to the heat capacity of the case 19, it is preferable to adjust by changing the heat capacity of the case 19. The reason is that in the plate-like ceramic body 2 made of silicon nitride or aluminum nitride having the same size, the heat capacity of aluminum nitride is about several to 10% larger than that of silicon carbide. Since the thickness is substantially the same, it is difficult to greatly change the heat capacity of the plate-like ceramic body 2. However, to adjust the depth of the metal plate thickness and the case 19 of the case 19, is because it adjust the casing 19 in a suitable heat capacity often a useful changing the material.

Further, in order to shorten the heating time and cooling time of the ceramic heater 1, the ratio S / V between the surface area S (cm ² ) of the case 19 and the volume V (cm ³ ) of the case 19 is 5 to 50 (1 / Cm), it was found that the plate-like ceramic body 2 can be heated and cooled more efficiently, which is preferable.

  When the ratio S / V is less than 5 (1 / cm), since the ratio of the surface area S to the volume V of the case 19 is small, the efficiency with which heat absorbed from the surface of the case 19 is dissipated out of the case 19 is improved. It is bad and heat tends to remain in the case 19. This is because when the plate-like ceramic body 2 is heated, radiant heat is easily absorbed by the case 19 and it is difficult to rapidly raise the temperature of the plate-like ceramic body 2.

If the ratio S / V is obtain ultra the 50 (1 / cm), or deform the attachment of the thickness is reduced too casing 19 of the surface area becomes too large case 19 of the case 19 in the apparatus, the case 19 by the vibration deformation There is a risk that the in-plane temperature difference of the wafer W may change due to fluctuations in the temperature distribution of the plate-like ceramic body 2, or the temperature difference in the wafer surface at the time of raising or lowering the temperature may increase.

  The ratio S / V was preferably 11 to 20 (1 / cm), and more preferably 13 to 15 (1 / cm).

  Next, a specific method for adjusting the ratio S / V to be in the above range will be described. Generally, when the metal plate thickness of the case 19 is increased, the S / V is decreased. Preferably, the thickness of the side wall of the case 19 is 0.5 to 3 mm, and the thickness of the bottom plate is 1 to 5 mm. More preferably, the thickness of the side wall is 0.5 to 2 mm and the thickness of the bottom plate is 1 to 3 mm. Further, by providing irregularities on the outer periphery of the case 19 and enlarging the surface of the case 19, the ratio S / V can be adjusted to be within the above-mentioned preferable range.

  Here, the case 19 indicates a metal part whose outer surface is made of metal except for the plate-like ceramic body 2 and the connecting member 17 among the parts forming the outer surface of the ceramic heater 1.

  Further, the cooling gas sprayed from the nozzle 24 hits the lower surface of the plate-like ceramic body 2, spreads radially along the lower surface of the plate-like ceramic body 2, and collides with the case 19 or a member attached to the case 19 to change the course. 19 is discharged to the outside of the ceramic heater 1 through the discharge hole 23 on the lower surface 21 of the ceramic heater 19. And the said cooling gas takes the heat | fever of the plate-shaped ceramic body 2, transfers one part heat to the case 19, and cooling gas is discharged | emitted. A part of the heat of the plate-like ceramic body 2 transmitted to the case 19 is efficiently dissipated from the outside of the case 19. The cooling gas sprayed from the nozzle 24 can efficiently take the heat of the plate-shaped ceramic body 2 by strongly colliding with the lower surface of the plate-shaped ceramic body, and the heated cooling gas transfers heat to the case 19. However, in order to increase the flow rate of the cooling gas injected from the nozzle 24 and efficiently discharge it, it is 1000 to 3200 times the total area S1 of the openings 24a of the plurality of attached nozzles 24. It is preferable to have a discharge hole 23 having an area S.

  When the area of S2 is 1000 times or less of the total area S1 of the opening 24a of the nozzle 24, the discharge hole 23 is small, so that the protruding amount of the cooling gas injected from the nozzle 24 is reduced and the plate-like ceramic body 2 is cooled. Efficiency is reduced, which is not preferable.

Further, the total area S1 of the opening 24a of the nozzle 24, the area of S2 is obtaining ultra 3200 times, the amount by which heat is transferred to the case 19 of the cooling gas heated by the plate-shaped ceramic body 2 is reduced, The effect of cooling the plate-like ceramic body 2 is reduced.

  Therefore, when the discharge hole 23 has an area S2 that is 1000 to 3200 times the total area S1 of the opening 24a of the nozzle 24, the cooling gas is efficiently applied to the plate-like ceramic body 2, and the plate-like ceramic body 2 The cooling gas can be circulated through the space surrounded by the case 19 and discharged from the discharge hole 23. Preferably, S2 is 1500 to 2500 times S1. More preferably, it is 1700-2300 times.

  Furthermore, when the cooling gas is allowed to flow as described above, an excellent cooling characteristic can be obtained because the pressure difference P between the space surrounded by the case 19 and the plate-shaped ceramic body 2 and the external space can be 50 to 13 kPa. .

  When the pressure difference P is 50 Pa or less, the flow rate of the cooling gas is small and the plate-like ceramic body 2 cannot be cooled in a short time.

  When the pressure difference P exceeds 13 kPa, the internal pressure increases and the space surrounded by the plate-shaped ceramic body 2 and the metal case expands and the volume increases, and the positions of the plate-shaped ceramic body and the case 19 shift and are placed on the plate-shaped ceramic body 2. The temperature distribution of the wafer may change.

  Preferably, the pressure difference P is 100 Pa to 1 kPa, more preferably 200 Pa to 500 Pa.

  Further, the resistance heating element 5 is arranged at a certain distance from the wafer heating surface 3, and the opposing space S of the resistance heating element 5 can be designed to be not more than 5 times the plate thickness t of the plate-like ceramic body 2. is necessary.

Also, it arranged so that it can heat the diameter 200mm to uniformly Moreover high temperature is exceeded large U E wafer W is facing distance S is preferably not less than 0.5 mm.

  Here, the facing interval S can be represented by the diameter of the largest circle in contact with the band of the resistance heating element 5 in the circumscribed circle of the resistance heating element 5 as shown in FIG.

When the distance S is obtain ultra 5 times the plate thickness t of the plate-shaped ceramic body 2, a cool spot on the wafer W to a temperature in the vicinity of the center of the spacing S is mounted on the wafer heating surface 3 of the reduced plate-shaped ceramic body 2 This is because there is a risk of occurrence. On the other hand, if the resistance heating element 5 is printed by the screen printing method when the interval S is less than 0.5 mm, the band of the resistance heating element 5 may be short-circuited due to the influence of ink bleeding or the like. This is because the internal temperature difference cannot be reduced.

  Furthermore, the ceramic heater 1 according to the present invention has an inner diameter of the circumscribed circle C with respect to the area of the circumscribed circle C surrounding the belt-shaped resistance heating element 5 when viewed in a projection plane parallel to one main surface of the plate-shaped ceramic body 2. The ratio of the area of the strip-like resistance heating element 5 in the region is 5% to 50%.

That is, when the ratio of the area of the belt-like resistance heating element 5 occupying the circumscribed circle C to the area of the circumscribed circle C surrounding the belt-like resistance heating element 5 is less than 5%, In the facing region, the facing space S of the facing region becomes too large with respect to the plate thickness t of the plate-like ceramic body 2, so that the surface temperature of the wafer heating surface 3 without the belt-like resistance heating element 5 is different from that of the other portions. This is because it becomes smaller and it is difficult to make the temperature of the wafer heating surface 3 uniform, and conversely, the strip-shaped resistance occupying the circumscribed circle C with respect to the area of the circumscribed circle C surrounding the strip-shaped resistance heating element 5. If the area ratio of the heating element 5 exceeds 50%, even if the thermal expansion difference between the plate-like ceramic body 2 and the strip-like resistance heating element 5 is approximated to 3.0 × 10 ⁻⁶ / ° C. or less. , The thermal stress acting between them is too large, the plate-like ceramic body 2 Is made of a ceramic sintered body that is not easily deformed, but its plate thickness t is as thin as 1 mm to 7 mm. Therefore, when the belt-like resistance heating element 5 is heated, the plate-like ceramic body is made concave on the wafer heating surface 3 side. 2 warpage occurs, the result becomes smaller than the periphery temperature of the central portion of the U E wafer W, there is a possibility that the temperature variation is large.

  Preferably, the ratio of the area of the belt-like resistance heating element 5 occupying the circumscribed circle C to the area of the circumscribed circle C surrounding the belt-like resistance heating element 5 is 10% to 30%, and more preferably 15% to 25%. % Is preferable.

  Furthermore, in order to express such an effect efficiently, it is preferable to set the film thickness of the strip-shaped resistance heating element 5 to 5 to 70 μm.

If the film thickness of the strip-shaped resistance heating element 5 is less than 5 μm, it is difficult to uniformly print the film thickness of the strip-shaped resistance heating element 5 by the screen printing method. If the thickness of obtaining super a 70 [mu] m, to the circumscribed circle C, and the ratio of the area occupied by the strip-shaped resistance heating element 5 large strip thickness of the resistance heating element 5 even less than 50%, the rigidity of the resistance heating element 5 become large, or deformed ceramic plate 2 with influence of expansion and contraction of the strip-shaped resistance heating element 5 due to a temperature change of the ceramic plate 5, it is difficult to print a uniform thickness by a screen printing U E wafer W temperature difference between the surface of there is a possibility that may become large. The preferred strip-like resistance heating element 5 has a thickness of 10 to 30 μm.

  FIG. 5 is an enlarged sectional view showing the vicinity of the ring-shaped contact member 17 of the ceramic heater 1 shown in FIG. The cross-section of the ring-shaped contact member 17 may be either polygonal or circular. However, when the plate-shaped ceramic body 2 and the contact member 17 are in contact with each other in a plane, the contact portion of the plate-shaped ceramic body 2 and the contact member 17 is in contact. If the width is 0.1 mm to 13 mm, the amount of heat of the plate-like ceramic body 2 flowing through the contact member 17 to the bottomed case 19 can be reduced. And the temperature difference in the surface of the wafer W is small, and the wafer W can be heated uniformly.

If the width of the contact portion of the contact member 17 is 0.1 mm or less, the contact portion may be deformed when the contact is fixed to the plate-like ceramic body 2, and the contact member may be damaged. Further, the width is 13mm in the contact portion of the contact member 17 when is exceeded flows into heat contact member of the plate-shaped ceramic body 2, and decreases the temperature of the peripheral portion of the plate-shaped ceramic body 2 uniform wafer W It becomes difficult to heat. Preferably, the width of the contact portion between the contact member 17 and the plate-like ceramic body 2 is 0.1 mm to 8 mm, more preferably 0.1 to 2 mm.

  Further, the thermal conductivity of the contact member 17 is preferably smaller than the thermal conductivity of the plate-like ceramic body 2. If the thermal conductivity of the contact member 17 is smaller than the thermal conductivity of the plate-like ceramic body 2, the temperature distribution in the wafer W surface placed on the plate-like ceramic body 2 can be heated uniformly, and the plate-like ceramic body 2. When the temperature is raised or lowered, the amount of heat transferred to the contact member 17 is small, and there is little thermal interference with the bottomed case 19, so that it is easy to change the temperature quickly.

  In the ceramic heater 1 in which the thermal conductivity of the contact member 17 is smaller than 10% of the thermal conductivity of the plate-like ceramic body 2, it is difficult for the heat of the plate-like ceramic body 2 to flow to the bottomed case 19 through the contact member. The heat flowing from the plate-like ceramic body 2 to the bottomed case 19 is increased by heat transfer or radiation heat transfer by gas (here, air), and the effect is small.

When the thermal conductivity of the contact member 17 is higher than the thermal conductivity of the plate-like ceramic body 2, the heat around the plate-like ceramic body 2 flows to the bottomed case 19 via the contact member 17, When the case 19 is heated, the temperature of the peripheral portion of the plate-like ceramic body 2 is lowered, and the temperature difference in the wafer W surface is increased, which is not preferable. Also, increased time case 19 having a bottom is cooled from higher temperatures bottomed casing 19 even if an attempt is cooled plate-like ceramic body 2 to inject air over from the gas injection port 24 from being heated is or, there is a possibility you or Tsu the name large time to a constant temperature during the heating at a constant temperature.

  On the other hand, as a material constituting the contact member 17, the Young's modulus of the contact member is preferably 1 GPa or more, and more preferably 10 GPa or more in order to hold a small contact portion. By using such a Young's modulus, the contact portion width is as small as 0.1 mm to 8 mm, and even if the plate-like ceramic body 2 is fixed to the bottomed case 19 with the bolt 16 via the contact member 17, the contact Without deforming the member 17, the plate-like ceramic body 2 can be held with high accuracy without being displaced or changing in parallelism.

  In addition, the precision which cannot be obtained with the contact member which consists of resin which added resin and glass fiber to the fluorine-type contact member can be achieved.

  As the material of the contact member 17, metals such as carbon steel made of iron and carbon and special steel added with nickel, manganese, and chromium are preferable because of their large Young's modulus. Further, as the material having a small thermal conductivity, so-called kovar of stainless steel or Fe—Ni—Co alloy is preferable, and the material of the contact member 17 is selected so as to be smaller than the thermal conductivity of the plate-like ceramic body 2. Is preferred.

  Furthermore, since the contact portion between the contact member 17 and the plate-like ceramic body 2 is small, and even if the contact portion is small, the contact portion is not liable to be lost and particles can be generated. The cross-section of the contact member 17 cut along a plane perpendicular to the body 2 is preferably circular rather than polygonal. When a circular wire having a cross-sectional diameter of 1 mm or less is used as the contact member 17, the plate-like ceramic body 2 and the bottomed case 19 It is possible to raise and lower the temperature of the wafer W uniformly and quickly without changing the position.

  Next, other configurations will be described.

  Work such as placing the wafer W on the wafer heating surface 3 or lifting it from the heating surface 3 is performed by lift pins 25 installed in the case 19 so as to be movable up and down. The wafer W is held in a state of being lifted from the wafer heating surface 3 by the wafer support pins 8 so as to prevent temperature variations due to contact with each other.

  Further, in order to heat the wafer W by the ceramic heater 1, the lift pin 25 is lowered after the wafer W carried to the upper part of the wafer heating surface 3 by the transfer arm (not shown) is supported by the lift pin 25. Wafer W is placed on wafer heating surface 3.

  Next, the power supply unit 6 is energized to cause the resistance heating element 5 to generate heat, and the wafer W on the wafer heating surface 3 is heated via the plate-like ceramic body 2. According to the present invention, the ceramic heater 1 The plate-shaped ceramic body 2 is connected to the bottomed case 19 via the contact member 17 that supports the plate-shaped ceramic body 2, so that the heat of the plate-shaped ceramic body 2 is more than necessary by the contact member 17 connected to the plate-shaped ceramic body 2. Therefore, the plate-like ceramic body 2 can be effectively soaked in a short time and the temperature of the wafer W can be heated uniformly.

  Furthermore, since the plate-like ceramic body 2 is formed of a silicon carbide sintered body or an aluminum nitride sintered body, the Young's modulus can be reduced to 200 GPa or more even when heat is applied, and the plate thickness can be reduced. Therefore, it is possible to shorten the heating time until heating to a predetermined processing temperature and the cooling time until cooling from the predetermined processing temperature to near room temperature, and it is possible to increase productivity and to increase the plate-like ceramic body 2. Is made of silicon carbide or aluminum nitride and has a thermal conductivity of 60 W / (m · K) or more, so that Joule heat of the resistance heating element 5 can be quickly transmitted even with a thin plate thickness.

The thickness of the plate-like ceramic body 2 is preferably 1 to 7 mm. When the thickness of the plate-like ceramic body 2 is less than 1 mm, the strength of the plate-like ceramic body 2 is lost, and the heat generated during cooling when the cooling air from the gas injection port 24 is blown when heated by the heat generated by the resistance heating element 5. The plate-like ceramic body 2 is not able to endure the stress and cracks are generated. If the thickness of the plate-shaped ceramic body 2 obtain ultra the 7 mm, the temperature during heating and cooling since the thermal capacity of the plate-shaped ceramic body 2 becomes larger undesirably long time to stabilize. More preferably, the thickness of the plate-like ceramic body 2 is 2 to 5 mm.

  As described above, when the heat capacity of the plate-like ceramic body 2 is reduced, the temperature distribution of the plate-like ceramic body 2 is deteriorated due to the heat drawn from the bottomed case 19. Therefore, the bottomed case 19 is configured to hold the plate-like ceramic body 2 at the outer peripheral portion thereof.

  As for the method of supplying power to the resistance heating element 5, the connection is made by pressing the power supply terminal 11 installed on the bottomed case 19 against the power supply part 6 formed on the surface of the plate-like ceramic body 2 with a spring (not shown). Secure and supply power. This is because when the terminal portion made of metal is embedded in the plate-like ceramic body 2 having a thickness of 1 to 7 mm, the thermal uniformity is deteriorated due to the heat capacity of the terminal portion. Therefore, as in the present invention, by pressing the power supply terminal 11 with a spring to ensure electrical connection, the thermal stress due to the temperature difference between the plate-like ceramic body 2 and the bottomed case 19 is relaxed, Electrical continuity can be maintained with high reliability. Further, an elastic conductor may be inserted as an intermediate layer in order to prevent the contact from becoming a point contact. This intermediate layer is effective by simply inserting a foil-like sheet. And it is preferable that the diameter by the side of the electric power feeding part 6 of the electric power feeding terminal 11 shall be 1.5-5 mm.

  Further, the temperature of the plate-like ceramic body 2 is measured by a thermocouple 27 whose tip is embedded in the plate-like ceramic body 2. As the thermocouple 27, it is preferable to use a sheath-type thermocouple 27 having an outer diameter of 0.8 mm or less from the viewpoint of responsiveness and workability of holding. In order to improve the reliability of temperature measurement, it is preferable that the tip of the thermocouple 27 has a hole formed in the plate-shaped ceramic body 2 and is fixed to the inner wall surface of the hole by a fixing member installed therein. . Similarly, it is also possible to perform temperature measurement by embedding a temperature measuring resistor such as a thermocouple of a wire or Pt.

  Further, when used as a ceramic heater 1 for forming a resist film, if the main component of the plate-like ceramic body 2 is silicon carbide, it does not react with moisture in the atmosphere and does not generate gas, so that the wafer W Even if the resist film is used for application to the top, fine wirings can be formed at high density without adversely affecting the structure of the resist film. At this time, it is necessary that the sintering aid does not contain nitrides that may react with water to form ammonia or amines.

In the silicon carbide sintered body forming the plate-like ceramic body 2, boron (B) and carbon (C) are added as sintering aids to the main component silicon carbide, or alumina (Al ₂ O ₃₎ After yttria _(Y 2 _{O 3)} a metal oxide or added and mixed well, such as, was processed into a flat plate, obtained by baking at 1900-2100 ° C.. Silicon carbide may be either mainly α-type or β-type.

Moreover, the aluminum nitride sintered body that forms the plate-like ceramic body 2 has a rare earth element oxide such as Y ₂ O ₃ or Yb ₂ O ₃ as a sintering aid for the main component aluminum nitride, if necessary. Then, an alkaline earth metal oxide such as CaO is added and mixed sufficiently, and after processing into a flat plate, it is obtained by firing at 1900 to 2100 ° C. in nitrogen gas.

  The plate ceramic body 2 mainly composed of silicon carbide or aluminum nitride preferably has a thermal conductivity of 160 W / (m · K) or more because the temperature difference in the wafer surface is further reduced.

  Further, the main surface opposite to the wafer heating surface 3 of the plate-like ceramic body 2 has a flatness of 20 μm or less and a surface roughness of the center line average roughness from the viewpoint of improving the adhesion with the insulating layer 4 made of glass or resin. The thickness (Ra) is preferably polished to 0.1 μm to 0.5 μm.

On the other hand, when the silicon carbide sintered body is used as the plate-like ceramic body 2, glass or resin is used as an insulating layer for maintaining insulation between the plate-like ceramic body 2 having semiconductivity and the resistance heating element 5. it is possible to use, in the case of using the glass and its thickness can not be maintained insulating withstand voltage is below 1.5kV in less than 100 [mu] m, the thickness conversely obtain ultra the 400 [mu] m, forming a plate-shaped ceramic body 2 Since the thermal expansion difference between the silicon carbide sintered body and the aluminum nitride sintered body is too large, cracks are generated and the insulating layer does not function. Therefore, when glass is used as the insulating layer, the thickness of the insulating layer 4 is preferably formed in the range of 100 to 400 μm, and desirably in the range of 200 μm to 350 μm.

  When the plate-like ceramic body 2 is formed of a sintered body mainly composed of aluminum nitride, an insulating layer made of glass is used to improve the adhesion of the resistance heating element 5 to the plate-like ceramic body 2. Form. However, when sufficient glass is added in the resistance heating element 5 and sufficient adhesion strength can be obtained by this, it can be omitted.

The glass forming this insulating layer may be crystalline or amorphous, and has a heat-resistant temperature of 200 ° C. or higher and a thermal expansion coefficient in the temperature range of 0 ° C. to 200 ° C. It is preferable to select and use a material having a thermal expansion coefficient in the range of −5 to + 5 × 10 ⁻⁷ / ° C. as appropriate. That is, if a glass whose thermal expansion coefficient is out of the above range is used, the difference in thermal expansion from the ceramic forming the plate-like ceramic body 2 becomes too large, so that defects such as cracks and delamination occur during cooling after baking the glass. It is because it is easy to occur.

  In addition, as a means for depositing an insulating layer made of glass on the plate-like ceramic body 2, an appropriate amount of the glass paste is dropped on the center of the plate-like ceramic body 2, and is spread and applied uniformly by a spin coating method. Alternatively, the glass paste may be baked at a temperature of 600 ° C. or higher after being uniformly applied by a screen printing method, a dipping method, a spray coating method, or the like. When glass is used as the insulating layer, the surface of the plate-like ceramic body 2 made of a silicon carbide sintered body or an aluminum nitride sintered body is heated to a temperature of about 850 to 1300 ° C. to deposit the insulating layer. By subjecting to an oxidation treatment, adhesion to an insulating layer made of glass can be enhanced.

Further, as the resistance heating element 5 material deposited on the insulating layer, a simple metal such as gold (Au), silver (Ag), copper (Cu), palladium (Pd) or the like is directly applied by a vapor deposition method or a plating method. Either a metal paste or a conductive metal oxide such as rhenium oxide (Re ₂ O ₃ ) or lanthanum manganate (LaMnO ₃ ) or a paste in which the above metal material is dispersed in a resin paste or glass paste. The conductive material may be prepared, printed by a screen printing method or the like in a predetermined pattern shape, and baked, and the conductive material may be bonded with a matrix made of resin or glass. When glass is used as the matrix, either crystallized glass or amorphous glass may be used, but crystallized glass is preferably used in order to suppress a change in resistance value due to thermal cycling.

However, if the resistance heating element 5 material using silver (Ag) or copper (Cu), since there is a possibility that migration occurs in such a case, the resistance heating element 5 the same as the insulating layer so as to cover What is necessary is just to coat | coat the coating layer which consists of material with the thickness of about 40-400 micrometers.

  The ceramic heater 1 of the present invention secures conduction by fixing the power supply terminal 11 to the resistance heating element 5 by brazing or a conductive adhesive in the power supply unit 6. The power feeding terminal 11 may be pressed against the terminal portion of the resistance heating element 5 with an elastic body to ensure conduction.

  Although the ceramic heater 1 of the type in which the resistance heating element 5 is formed on the surface of the plate-like ceramic body 2 has been described so far, the resistance heating element 5 may be incorporated in the plate-like ceramic body 2. .

  For example, when the plate-like ceramic body 2 whose main component is made of aluminum nitride is used, first, W or WC is used as the material of the resistance heating element 5 from the viewpoint of a material that can be fired simultaneously with aluminum nitride. The plate-like ceramic body 2 is formed into a disk shape after sufficiently mixing raw materials containing aluminum nitride as a main component and appropriately containing a sintering aid, and a paste made of W or WC is formed on the surface of the pattern shape of the resistance heating element 5. It can be obtained by firing at a temperature of 1900 to 2100 ° C. in a nitrogen gas after being printed on and another aluminum nitride molded body is stacked and adhered thereto.

  Conduction from the resistance heating element 5 may be achieved by forming a through hole in the aluminum nitride base material, filling a paste made of W or WC, and then firing the electrode so that the electrode is drawn to the surface. Further, when the heating temperature of the wafer W is high, the power feeding unit 6 applies a paste mainly composed of a noble metal such as Au or Ag on the through hole and bakes it at 900 to 1000 ° C. The oxidation of the body 5 can be prevented.

First, 1.0 % by mass of yttrium oxide in terms of weight was added to the aluminum nitride powder, and further kneaded for 48 hours with a ball mill using isopropyl alcohol and urethane balls to produce an aluminum nitride slurry.

  Next, the aluminum nitride slurry was passed through 200 mesh to remove urethane balls and ball mill wall debris, and then dried at 120 ° C. for 24 hours in an explosion-proof dryer.

  Next, the obtained aluminum nitride powder was mixed with an acrylic binder and a solvent to produce an aluminum nitride slip, and a plurality of aluminum nitride green sheets were produced by a doctor blade method.

  Then, a laminate was formed by laminating a plurality of obtained aluminum nitride green sheets.

  Thereafter, the laminate is degreased at a temperature of 500 ° C. for 5 hours in a non-oxidizing gas stream, and then fired at a temperature of 1900 ° C. for 5 hours in a non-oxidizing atmosphere to produce a plate-like ceramic body. did.

  Then, the aluminum nitride sintered body was ground to have a plate thickness of 3 mm, and a disc shape having a diameter of 315 mm to 345 mm with a plate thickness of 3 mm at the central portion and an annular thickness of 3.5 mm only at the peripheral portion. A plurality of plate-like ceramic bodies were produced, and three through-holes were evenly formed on a concentric circle 60 mm from the center. The through-hole diameter was 4 mm.

  Next, in order to deposit a resistance heating element on the plate-shaped ceramic body, a conductive paste prepared by kneading Au powder, Pd powder, and glass paste with a binder added as a conductive material is predetermined by screen printing. After printing to the pattern shape, the organic solvent is dried by heating to 150 ° C., and after further degreasing treatment at 550 ° C. for 30 minutes, baking is performed at a temperature of 700 to 900 ° C., so that the thickness is 50 μm. A resistance heating element was formed. The pattern arrangement of the resistance heating element is divided into a circle and an annular shape in the radial direction from the central portion, a pattern is formed in one circular shape in the central portion, and two patterns are formed in the outer annular portion. Furthermore, a total of 7 patterns of 4 patterns were formed on the outside. The diameter of the circumscribed circle C of the four outermost patterns was 310 mm. After that, a power supply part was brazed and fixed to the resistance heating element, and a resistance heating element other than the power supply part was coated with glass to produce a heater part with improved corrosion resistance.

The bottomed case is made of an Fe-Cr-Ni-based alloy, and the bottom surface has a 2.0 mm plate and a 1.0 mm thick plate constituting the side wall, and the inner and outer surfaces of the case are formed. or buffed respectively, to prepare a case which was adjusted reflectance of infrared rays or by electrolytic polishing. Also, a metal plate subjected to heat treatment in an oxidizing atmosphere of 100 to 400 ° C., after changing the absorption of the infrared to form an oxide film on the surface, or by sandblasting or grinding machining or plating the backside table The infrared absorption rate on the back surface was adjusted. And the gas injection port, the thermocouple, and the conduction | electrical_connection terminal were attached to the bottom face in the predetermined position. The distance from the bottom surface to the plate-like ceramic body was 20 mm.

  Thereafter, a plate-like ceramic body is overlaid on the opening of the bottomed case, and a bolt is passed through the outer peripheral portion thereof, so that the plate-like ceramic body and the bottomed case do not directly contact each other. The ceramic heater was elastically fixed by interposing and screwing a nut through an elastic body from the contact member side.

  Moreover, the ceramic heater was produced by two structures, the support structure A which supports the lower surface of the peripheral part of the plate-shaped ceramic body, and the support structure B which supports the outer peripheral end surface of the plate-shaped ceramic body. In the support structure A, the diameter of the plate-like ceramic body is the same as the diameter of the case.

  The contact member had a circular cross section and a ring shape. The size of the circular cross section was 1 mm in diameter. The material of the contact member was SUS304 or carbon steel. The produced various ceramic heaters were designated as sample Nos. 1-10.

The produced ceramic heater was evaluated using a temperature measuring wafer having a diameter of 300 mm in which temperature measuring resistors were embedded in 29 locations. A power supply is attached to each ceramic heater, the temperature of the wafer W is raised from 25 ° C. to 200 ° C. in 5 minutes, the temperature of the wafer W is set to 200 ° C., and then the average temperature of the wafer W is 200 ° C. ± 0.5 ° C. The mixture was heated until it became constant within the range, and then the temperature was maintained for 10 minutes. Then, while the ceramic heater is being heated, the wafer W is lifted with a lift pin and cooled to room temperature of 25 ° C., then the wafer W is placed on the wafer heating surface, and each part of the wafer W until the average temperature in the wafer W surface reaches 200 ° C. Was measured, and the difference between the maximum temperature and the minimum temperature in the wafer W plane with respect to the time axis was determined to obtain the temperature difference of the wafer during the transition. Further, the wafer W was placed, and the time until the average temperature reached 200 ° C. was measured as the response time. Also, ceramics heater to 200 ° C. from 30 ° C. After holding at 5 minutes the temperature was raised 5 minutes, after the temperature cycle to cool for 30 minutes repeated 1000 cycles, the wafer temperature of 200 ° C. was set as 10 minutes after the room The difference between the maximum value and the minimum value was measured as the temperature difference in the steady state of the wafer W.

Each result is as shown in Table 1.

Sample No. in Table 1 1, the temperature difference between the steady state of the wafer since the infrared absorptivity of the case inner surface 30% super strong point 51% and too large as 2.23 ° C., was not particularly preferably greater and response time 78 seconds.

  Sample No. 10 had an infrared absorption rate of 35% on the inner surface of the case, and the temperature difference during steady state of the wafer was as large as 0.93 ° C., and the response time was as large as 61 seconds.

  On the other hand, sample Nos. 2 to 9 are excellent because the temperature difference in the wafer surface is as small as 0.65 ° C. or less and the response time is as small as 58 seconds or less. It has been found that ceramic heaters with a 30% or less exhibit excellent characteristics.

  In addition, the composition of the case is the mass%, the sample No. 1 in which Cr is 17 to 26%, Ni is 8 to 22%, C is 0.2% or less, and N is 0.1% or less. 2 to 9, it was found that the temperature difference of the wafer at the time of steady state was as small as 0.65 ° C. or less, and the wafer temperature difference at the time of transition was as small as 6.13 ° C. or less.

  In addition, the sample No. with a surface roughness Ra of 5 μm or less on the inner surface of the case. 2 to 9 similarly show preferable characteristics, and in particular, sample Nos. With surface roughness of 1 μm or less. 3 to 9, it was found that the temperature difference of the wafer in the steady state was 0.49 ° C. or less and the temperature difference of the wafer in the transition was as small as 4.35 ° C. or less, which was further preferable.

Sample No. 1 of Example 1 The same case as 3 was plated with Ag, Au, and Cu, and evaluated in the same manner as in Example 1. The results are shown in Table 2.

  Sample No. No. 21 has an infrared absorptivity of 20% on the inner surface of the case and an infrared absorptivity of the outer surface of the case equal to 20%. The wafer temperature difference was as large as 4.23 ° C.

  In contrast, sample no. In Nos. 22 to 24, since the infrared absorption rate of the inner surface of the case was smaller than the infrared absorption rate of the outer surface, it was found that the temperature difference between the wafers in a steady state was as small as 0.35 ° C. or less and showed excellent characteristics.

  In addition, the sample No. 1 was plated with Ag, Cu or Au on the inner surface of the case. Nos. 22 to 24 show that the absorption rate of the inner surface of the case is small, the temperature difference between the wafers in a steady state is as small as 0.35 ° C. or less, and the temperature difference between the wafers in a transient state is 3.76 ° C. or less. It was.

Sample No. 1 of Example 1 The ratio of the diameter of the circumscribed circle of the resistance heating element to the diameter of the plate ceramic body is changed by changing the diameter of the circumscribed circle of the resistance heating element with respect to the diameter of the plate-like ceramic body using the same case as 3 Samples with different values were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 3.

  Sample No. When the contact member is connected in a ring shape so as to support the lower surface of the periphery of the plate-like ceramic body as in 31 to 35, it is possible to obtain preferable characteristics in which the temperature difference of the wafer in the steady state and the temperature difference of the wafer in the transient state are small. I understood.

  On the other hand, sample No. It has been found that when the contact member is connected so as to surround the peripheral end face of the plate-like ceramic body as in 36 to 41, a ceramic heater having a slightly smaller outer shape and preferable characteristics can be obtained.

  Sample No. When the diameter of the circumscribed circle of the resistance heating element is 90 to 99% of the diameter of the plate-like ceramic body as in 32 to 40, the temperature difference of the wafer in the steady state is as small as 0.42 ° C. or less, and the wafer in the transient state It was found that the temperature difference was as small as 4.70 ° C. or less, and preferable characteristics were obtained.

  Furthermore, sample no. When the diameter of the circumscribed circle of the resistance heating element is 92 to 95% of the diameter of the plate-like ceramic body as in 33 to 35, the temperature difference of the wafer in the steady state is as small as 0.37 ° C. or less, and the wafer in the transient state The temperature difference was as small as 4.29 ° C. or less, and it was found that preferable characteristics were obtained.

  Furthermore, sample no. When the diameter of the circumscribed circle of the resistance heating element is 95 to 98% of the diameter of the plate-like ceramic body as in 36 to 39, the temperature difference of the wafer at the steady state is as small as 0.33 ° C. or less, and the wafer at the transient time The temperature difference was as small as 4.28 ° C. or less, and it was found that preferable characteristics were obtained.

  A plate-like ceramic body was produced in the same manner as in Example 1.

  Then, the aluminum nitride sintered body is ground to produce a plurality of disk-shaped ceramic bodies 2 having a disk thickness of 3 mm and a diameter of 210 mm to 330 mm, and further penetrates three places evenly on a concentric circle of 60 mm from the center. A hole was formed. The through-hole diameter was 4 mm.

  Next, in order to deposit the resistance heating element 5 on the plate-like ceramic body 2, a conductor paste produced by kneading a glass paste to which Au powder, Pd powder and a binder having the same composition as described above are added as a conductive material. Is printed in a predetermined pattern shape by a screen printing method, heated to 150 ° C. to dry the organic solvent, further degreased at 550 ° C. for 30 minutes, and then baked at a temperature of 700 to 900 ° C. Thus, the resistance heating element 5 having a thickness of 50 μm was formed.

  The resistance heating element zone 4 is arranged in such a manner that a resistance heating element zone is formed in one circular shape at the center, and an annular ring is divided into two equal resistance heating element zones on the outer side, and an annular ring is formed on the outer side. A total of seven resistance heating element zones were divided into two resistance heating element zones. And the sample which made the diameter of circumscribed circle C of four resistance heating element zones of the outermost periphery 205-310mm was produced. After that, the heater 6 was manufactured by brazing and fixing the feeding portion 6 to the resistance heating element 5 and forming a protective film with glass on the resistance heating element.

  Further, the bottomed metal case was made of Al alloy, steel, and stainless steel, and a metal case was produced by changing the thickness of the bottom surface of the case and the thickness constituting the side wall portion. And the nozzle for gas injection, the thermocouple, and the conduction | electrical_connection terminal were attached to the bottom face of the metal case in the predetermined position. The distance from the bottom surface to the plate-like ceramic body was 25 mm.

  After that, a plate-shaped ceramic body is overlaid on the opening of the bottomed metal case, and a bolt is passed through the outer periphery thereof, so that the plate-shaped ceramic body and the bottomed metal case do not directly contact each other. A ceramic heater was obtained by elastically fixing a member by interposing a member and screwing a nut through an elastic body from the contact member side.

  Moreover, the ceramic heater was produced by two structures, the support structure A which supports the lower surface of the peripheral part of a plate-shaped ceramic body, and the support structure B which supports the outer peripheral surface of a plate-shaped ceramic body. In the support structure A, the diameter of the plate-like ceramic body and the diameter indicating the outer shape of the metal case are the same.

  The contact member 17 has a circular cross section and a ring shape. The size of the circular cross section was 1 mm in diameter. The material of the contact member was SUS304 or carbon steel. The produced various ceramic heaters were designated as sample Nos. 42 to 47.

  The produced ceramic heater was evaluated in the same manner as in Example 1.

Each result is as shown in Table 4.

  Sample No. in which the heat capacity of the metal case of the ceramic heater 1 of the present invention is 0.5 to 3 times the heat capacity of the plate-like ceramic body. Nos. 43, 44, 46, and 47 have a small wafer temperature difference of 0.33 ° C. or less during steady state, a wafer temperature difference of 3.88 ° C. or less during transition, and an excellent response time of 28 seconds or less. It has been found that it exhibits characteristics.

  On the other hand, Sample No. whose heat capacity of the metal case is 0.18 times the heat capacity of the plate-like ceramic body. No. 42 had a response time as large as 43 seconds, a steady-state wafer temperature difference of 0.46 ° C., and a transient wafer temperature difference of 4.53 ° C ..

  In addition, Sample No. in which the heat capacity of the metal case is 3.4 times the heat capacity of the plate-like ceramic body. No. 45 had a response time as large as 42 seconds, a wafer temperature difference of 0.49 ° C. in a steady state, and a wafer temperature difference of 4.67 ° C. in a transient state.

  Accordingly, it has been found that the heat capacity of the metal case of the ceramic heater 1 is more excellent when it is 0.5 to 3 times the heat capacity of the plate-like ceramic body.

  A plate-like ceramic body was produced in the same manner as in Example 1, a metal case was produced, the thickness of the metal case was changed, and the ratio S / V between the case surface area S and the case volume V was changed. A heater was produced.

  And it evaluated similarly to Example 1. FIG.

The results are shown in Table 5.

  Sample No. with a ratio S / V of the surface area S of the case to the volume V of the case of 5 to 50 (1 / cm). 55-57 and 59-61 have a wafer temperature difference of 0.33 ° C. or less during steady state, a wafer temperature difference of less than 3.51 ° C. during transition, and a response time of 29 seconds or less. won.

  Accordingly, it has been found that the ratio S / V between the case surface area S and the case volume V is preferably 5 to 50 (1 / cm).

  A plate-like ceramic body was produced in the same manner as in Example 1. The support structure A is a sample No. 4 and the support structure B is sample No. It was produced according to No.12. The thickness of the plate-like ceramic body was 2 mm or 3 mm. Further, a ceramic heater in which the facing interval S shown in FIG. 3 was adjusted to 2 to 17 mm was produced and evaluated in the same manner as in Example 1.

The results are shown in Table 6.

  Sample No. 2 in which the opposing spacing S of the resistance heating elements is 5 times or less the thickness of the plate-like ceramic body. 65 and 67 to 70 were found to be preferable because the temperature difference in the wafer W surface during steady state was as small as 0.30 ° C. or less and the temperature difference in the wafer surface during transition was as small as 3.3 ° C. or less. The response time of the support structure A is the sample No. 64 from 27 seconds, sample no. 65, 24 seconds, and the response time of the support structure B is no. 66, 22 seconds, the sample No. It turned out that it is as small as 21 seconds or less like 67-70.

A plate-shaped ceramic body 2 was prepared in the same manner as in Example 1, and the front and back surfaces of the sintered body were ground to obtain a disk-shaped plate-shaped ceramic body 2 having a diameter of 320 mm and a thickness of 3 mm. The other main surface of the plate-like ceramic body 2 contains 50% by mass of metallic silver and 50% by mass of B ₂ O ₃ .SiO ₂ .ZnO glass (thermal expansion coefficient 4.4 × 10 ⁻⁶ / ° C.). A paste was prepared by adding a solvent to the powder.

Then, the paste is printed on the other main surface of the plate-like ceramic body 2 in the shape of a strip-like resistance heating element 5 by a screen printing method with a thickness of 20 μm, and for the circumscribed circle C surrounding the strip-like resistance heating element 5, Ceramic heaters were produced by changing the ratio of the area occupied by the strip-shaped resistance heating element 5. And it evaluated similarly to Example 1. FIG. The results are shown in Table 7.

As shown in sample Nos. 72 to 79, the sample in which the ratio of the area occupied by the band-shaped resistance heating element 5 to the circumscribed circle C of the band-shaped resistance heating element 5 is in the plane of the wafer W It can be seen that the temperature difference is as small as 0.29 ° C. or less, which is more preferable. However, like the sample No. 71, the sample in which the ratio of the area occupied by the band-shaped resistance heating element 5 to the circumscribed circle C surrounding the band-shaped resistance heating element 5 is less than 5% is the temperature difference in the wafer W plane. Was slightly large at 0.35 ° C. Furthermore, sample No.80 whereas circumscribed circle C surrounding the resistance heating element 5 of the strip, a high temperature in a portion of the wafer W from the ratio of the area occupied by the resistance heating element 5 of the strip is obtain ultra 50% A hot area appeared and the in-plane temperature difference of the wafer W increased to 0.38 ° C. Therefore, it was found that the ratio of the area occupied by the band-shaped resistance heating element 5 to the circumscribed circle C surrounding the band-shaped resistance heating element 5 is preferably 5 to 50%.

  Moreover, the temperature difference in the wafer surface of sample Nos. 73 to 77 was as small as 0.24 ° C., and it was found that the ratio of the area occupied by the strip-shaped resistance heating element 5 was more preferably 10 to 30%.

  Further, it was found that the temperature difference in the wafer surface of sample Nos. 74 to 76 was as small as 0.19 ° C. and the ratio of the area occupied by the strip-shaped resistance heating element 5 was 15 to 25%, which was most preferable. .

  Sample No. 1 of Example 1 The ceramic heater 1 was produced according to the configuration of No. 3. Further, the plate-shaped ceramic body 2 is overlapped on the opening of the bottomed case 19 and a bolt is passed through the outer peripheral portion thereof, so that the plate-shaped ceramic body 2 and the bottomed case 19 do not directly contact each other. The ceramic heater 1 was obtained by interposing the contact member 17 and elastically fixing the elastic body from the contact member 17 side and screwing the nut in place. The contact member 17 has a trapezoidal cross section and a ring shape that supports the periphery of the plate-like ceramic body 2. Each of the ceramic heaters has a trapezoidal cross-sectional size in which the lower side is 4 mm and the height is 2 mm, the upper side is 0.05 to 4 mm, the lower side is 15 mm, the height is 2 mm, and the upper side is 8 to 15 mm. Attached. The contact member 17 is made of SUS304 or carbon steel. The produced various ceramic heaters 1 were designated as sample Nos. 81-89.

  Evaluation was performed in the same manner as in Example 1.

Each result is as shown in Table 8.

  As can be seen from Table 8, sample no. No. 81, the contact portion 17 between the contact member 17 and the plate-like ceramic body 2 has a small width of 0.05 mm, and the response time and the temperature difference of the wafer are small, but particles that appear to be from the edge of the contact member are generated during use. I could not use it. Sample No. 89 had a contact portion width of 15 mm and a wafer temperature difference of 0.34 ° C., which showed slightly inferior characteristics as a ceramic heater for uniformly heating the wafer.

  In contrast, sample no. Nos. 82 to 88 have a width of the contact portion between the contact member and the plate-like ceramic body in the range of 0.1 to 13 mm, the wafer temperature difference is 0.24 ° C. or less, and the response time is as small as 25 seconds or less. The characteristics are shown.

  Furthermore, the temperature difference of the wafer at the time of transition is the sample number. Except 81, the smaller the width of the contact portion, the smaller the temperature difference of the wafer during the transition, and the sample whose contact member 17 is the portion where the contact member 17 contacts the plate-like ceramic body 2 is 0.1 mm to 13 mm. No. 82 to 88 were found to be preferable because the temperature difference of the wafer during the transition was as small as 3.31 ° C. or less.

  Therefore, it has been found that the width of the contact portion in contact with the plate-like ceramic body is preferably 0.1 to 13 mm in a cross section obtained by cutting the contact member along a plane perpendicular to the plate-like ceramic body.

  In the same process as in Example 1, the amount of yttrium oxide added was changed in the range of 0.1 to 5% by mass to produce a plate-like ceramic body 2 in which the thermal conductivity was changed. Moreover, the contact member 17 whose width of the contact part which contacts the plate-shaped ceramic body 2 was 2 mm was produced using SUS304, SUS403, Fe-Ni-Co alloy (Kovar), carbon steel, and aluminum. The plate-shaped ceramic body 2 and the contact member 17 are combined so that the ratio of the thermal conductivity of the plate-shaped ceramic body 2 and the thermal conductivity of the contact member 17 is 1 to 128%. A case 19 having a bottom made of aluminum was attached to the ceramic heater 1 through 17.

  Sample No. 91 to 98 used a metal contact member 17, and the bottomed case 19 had a diameter of 330 mm, a side wall thickness of 1.0 mm, a bottom thickness of 2.0 mm, and a depth of 30 mm. Sample No. Since 99 and 100 are resin contact members 17 whose Young's modulus is less than 1 GPa, the deformation of the trapezoidal contact member 17 is large, and there is a possibility that the life when used as a ceramic heater is short. The bottomed case had a diameter of 340 mm, a side wall thickness of 1.0 mm, a bottom surface thickness of 2.0 mm, and a depth of 30 mm.

  And it evaluated similarly to Example 1. FIG.

The results are shown in Table 9.

  SUS304, Fe-Ni-Co alloy, SUS403, carbon steel is used as the contact member 17 and is combined with aluminum nitride having different thermal conductivity, and the thermal conductivity of the contact member 17 is smaller than that of the plate-like ceramic body. . It was found that the ceramic heaters 91 to 97, 99, and 100 showed excellent characteristics such that the response time was within 27 seconds and the temperature difference of the wafer during steady state was 0.29 ° C. or less.

  However, sample no. In No. 98, the thermal conductivity of the contact member 17 was larger than that of the plate-like ceramic body, the response time was slightly large as 29 seconds, and the wafer temperature difference was relatively large at 0.34 ° C.

  Sample No. 99 and No. In the ceramic heater in which the contact member 17 is made of resin as in 100, the response times were slightly large as 26 seconds and 27 seconds, respectively, and the temperature difference between the wafers in a steady state was slightly large as 0.29 and 0.28 ° C. Since the resin contact member is deformed by a repeated temperature cycle, it is considered that the temperature difference between the wafers in a steady state becomes large.

  Accordingly, it has been found that a ceramic heater whose contact member has a thermal conductivity smaller than that of the plate-like ceramic body exhibits excellent characteristics with small response characteristics and wafer temperature differences.

  In addition, it is found that a ceramic heater having a thermal conductivity of 17 to 70% of the thermal conductivity of the plate-like ceramic body has a small temperature difference of 0.25 ° C. or less during steady state and exhibits further excellent characteristics. It was.

  A plate-like ceramic body 2 made of aluminum nitride having a Young's modulus of 300 GPa was produced in the same manner as in Example 1. Further, the width of the contact portion of the contact member 17 that contacts the plate-like ceramic body 2 using SUS304, SUS403, Fe—Ni—Co alloy (Kovar), carbon steel, aluminum, tin, and tin-lead alloy is 0.1 mm. Contact members 17 having different Young's moduli were produced. Then, a bottomed case made of aluminum was attached to the plate-like ceramic body 2 through the contact member 17 in the same manner as in Example 1 to produce a ceramic heater.

  And it evaluated similarly to Example 1. FIG.

The results are shown in Table 10.

  Sample No. consisting of the contact member 17 having a Young's modulus of 1 GPa or more. It has been found that the ceramic heaters 101 to 107 have favorable characteristics such that the response time is as small as 26 seconds or less, and the temperature difference between the wafers in a steady state is 0.28 ° C. or less.

  However, sample no. The ceramic heaters made of 98 fluororesins and fiber-filled resins each had a response time as large as 29 seconds, and the wafer temperature difference in a steady state was slightly large at 0.49 ° C.

  Therefore, it has been found that a ceramic heater having a Young's modulus of 1 GPa or more and smaller than the plate-like ceramic body 2 is preferable.

  A plate-like ceramic body 2 was produced in the same manner as in Example 1. Further, the contact member 17 is made of carbon steel with a trapezoidal ceramic heater 1 and the contact member 17 made of carbon steel with a circular cross section, and the plate-like ceramic body 2 with the contact member 17 interposed therebetween. The bottomed case 19 made of aluminum was attached to produce the ceramic heater 1.

And it evaluated similarly to Example 1. FIG. The results are shown in Table 11.

  Sample No. The ceramic heaters with trapezoidal contact members 111 and 112 had a response time of 24 and 23 seconds and a wafer temperature difference of 0.28 ° C. in a steady state. It was found that the contact member 17 having a circular cross-section such as 113 and 114 had a response time as small as 20 seconds and 19 seconds, and the temperature difference between the wafers was also as small as 0.18 ° C. and 0.15 ° C. .

  In particular, sample no. It was found that the ceramic heater having a circular cross section of the contact member such as 114 and a diameter of 1 mm or less showed extremely excellent characteristics with a response time of 19 seconds and a wafer temperature difference of 0.15 ° C.

It is sectional drawing which shows the ceramic heater of this invention. It is sectional drawing which shows the other example of the ceramic heater of this invention. It is a figure which shows the resistance heating element of the ceramic heater of this invention. It is a figure which shows the other resistance heating element of the ceramic heater of this invention. It is sectional drawing which shows the contact member periphery of the ceramic heater of this invention. It is sectional drawing which shows the other contact member periphery of the ceramic heater of this invention. It is sectional drawing which shows the conventional ceramic heater. It is a figure which shows the resistance heating element of the conventional ceramic heater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 71: Ceramic heater 2, 72: Plate-shaped ceramic body 3, 73: Mounting surface 5, 75: Resistance heating element 6: Power supply part 8: Support pin 10: Guide member 11, 77: Power supply terminal 16: Bolt 17 : Contact member 18: elastic body 20: nut 21: bottom 23: discharge hole 24: gas injection port 25: wafer lift pin 26: through hole 27: thermocouple 28: guide member 29, 79: case W: semiconductor wafer

Claims (20)

A heater unit having a resistance heating element on one main surface of a plate-like ceramic body mainly composed of aluminum nitride or silicon carbide and a wafer heating surface on the other main surface, and supplying power to the resistance heating element A power supply terminal, a bottomed case connected to the plate-like ceramic body so as to wrap the power supply terminal, a contact member that supports a peripheral portion of the plate-like ceramic body in a ring shape and connects to the case, and the plate-like A non-heat-generating region where the resistance heating element does not exist is provided outside the circumscribed circle of the resistance heating element around the ceramic body, and the case includes a nozzle that ejects a gas for cooling the plate-like ceramic body; A ceramic heater, wherein the inner surface has an infrared absorptance of 30% or less, and the thickness of the non-heat-generating region is larger than the thickness of the central portion of the plate-like ceramic .   The ceramic heater according to claim 1, wherein the infrared absorption rate of the inner surface of the case is smaller than the infrared absorption rate of the outer surface.   The case is made of metal, and in terms of mass%, Cr: 17 to 26%, Ni: 8 to 22%, C: 0.2% or less, N: 0.1% or less, and the balance is made of Fe and inevitable components. The ceramic heater according to claim 1 or 2, characterized by the above.   The ceramic heater according to claim 1, wherein the case has a surface roughness Ra of 5 μm or less.   The ceramic heater according to claim 1, wherein an infrared reflecting layer is formed on an inner surface of the case.   The ceramic heater according to claim 5, wherein the reflective layer is a noble metal layer such as Ag, Cu, or Au.   The ceramic heater according to any one of claims 1 to 6, wherein the contact member is connected in a ring shape so as to support a lower surface around the plate-shaped ceramic body.   The ceramic heater according to claim 1, wherein the contact member is connected so as to surround an end surface around the plate-shaped ceramic body.   The ceramic heater according to any one of claims 1 to 8, wherein a diameter of a circumscribed circle of the resistance heating element is 90 to 99% of a diameter of the plate-shaped ceramic body.   The ceramic heater according to claim 9, wherein a diameter of a circumscribed circle of the resistance heating element is 92 to 95% of a diameter of the plate-like ceramic body.   The ceramic heater according to claim 9, wherein a diameter of a circumscribed circle of the resistance heating element is 95 to 98% of a diameter of the plate-like ceramic body. The ceramic heater according to any one of claims 1 to 11, wherein the heat capacity of the case is 0.5 to 3.0 times the heat capacity of the plate-like ceramic body. Surface area S of the case (cm ² ) And volume V (cm) of the case ³ The ratio S / V to 5) (50/1 / cm) of the ceramic heater according to any one of claims 1 to 12. Ceramic heater according to any one of claims 1 to 13, characterized in that opposing distance S of the resistance heating element is not more than 5 times the thickness of the plate-like ceramic body. The thickness of the plate-shaped ceramic body is 1 to 7 mm, any one of claims 1-14 in which the ratio of the area of the resistive heating element to the area of the circumscribed circle of the resistance heating element is characterized in that it is a 5-50% A ceramic heater as described in 1.   The ceramic heater according to any one of claims 1 to 15, wherein a width of the contact member in contact with the plate-like ceramic body is 0.1 to 13 mm. The ceramic heater according to any one of claims 1 to 16 , wherein a thermal conductivity of the contact member is smaller than a thermal conductivity of the plate-shaped ceramic body. The Young's modulus of the contact member at least 1 GPa, the ceramic heater according to any one of claims 1 to 17, characterized in that less than the Young's modulus of the plate-shaped ceramic body. Ceramic heater according to any one of claims 1 to 18, the cross section of the contact member is characterized in that it is a circular shape. The diameter of the said contact member is 1 mm or less, The ceramic heater of Claim 19 characterized by the above-mentioned.

Images