JP5865566B2 - Ceramic heater - Google Patents

Description

  The present invention relates to a ceramic heater.

  A multi-zone type in which a plurality of heating resistors are embedded in a base made of a ceramic sintered body and the heating mode of each heating resistor is controlled independently in order to increase the temperature control accuracy of the mounting surface on which the wafer is mounted A ceramic heater has been proposed (see Patent Document 1).

JP 2009-009795 A

  However, there is room for improving the control accuracy of the temperature distribution mode on the mounting surface, such as controlling the central portion of the mounting surface to be higher or lower than the surrounding portion, or controlling the central portion and the surrounding portion to be substantially isothermal. Still left.

  Therefore, an object of the present invention is to provide a ceramic heater capable of improving the control accuracy of the temperature distribution on the mounting surface.

The ceramic heater according to the first aspect of the present invention is a first heating resistor which is made of a ceramic sintered body and has a mounting surface on which a semiconductor wafer is mounted and is embedded in the base so as not to short-circuit each other. A designated area in which the existence ranges of the first heating resistor and the second heating resistor overlap with each other in the normal direction of the mounting surface. The first heating resistor and the second heating resistor are arranged so that the watt density distribution modes of the first heating resistor and the second heating resistor are different in the designated area. configured, each of the first heating resistor and the second heating resistor in the designated area, a reverse gradient polarity watt density in the specified direction which is parallel to the mounting surface, The first heating resistor is disposed adjacent to the first heating resistor element disposed in each of the plurality of first annular sections spaced from each other so as to overlap the reference point on the placement surface. And a first connecting element that connects the first heating resistors arranged in one annular section, and the second heating resistors overlap each other around the reference point on the placement surface. A second connecting element for connecting the second heating resistor element disposed in each of the plurality of second annular sections spaced apart from each other and the second heating resistor element disposed in the adjacent second annular section. And the first heating resistance element is disposed in the first annular section away from the reference point, with the direction from the reference point toward the outer edge of the mounting surface as the designated direction. So that the watt density is higher On the other hand, the watt density of the first connecting element is reduced as the second heating resistance element is disposed in the second annular section that is farther from the reference point. Is lower than the watt density of the first heating resistance element, and the watt density of the second connection element is lower than the watt density of the second heating resistance element .

  According to the ceramic heater of the present invention, different temperature distributions can be formed by each of the first and second heating resistors in at least the designated area of the mounting surface. The “designated area” means an area where the existence ranges of the first and second heating resistors overlap in the normal direction of the placement surface. The “existing range” means a closed range or region in which all or almost all of the outline is defined by the outline of each heating resistor.

  For this reason, only by changing the combination of electric power supplied to each of the first and second heating resistors, the temperature distribution as a result of combining the temperature distributions formed by the respective heating resistors varies. As a result, the temperature distribution on the mounting surface is a desired shape (for example, a temperature gradient such that the center of the mounting surface is hot compared to the outer peripheral portion, or vice versa. The central portion of the mounting surface can be controlled with high accuracy to a temperature gradient that is lower than the outer peripheral portion.

The gradient polarity of the watt density in the specified direction parallel to the mounting surface of each of the first heating resistor and the second heating resistor in the specified area is opposite, By controlling the power supplied to each of the second heating resistors, a temperature gradient is formed as a result of combining the temperature gradients formed by the heating resistors in the specified direction in the specified area. The temperature gradient formed in the specified direction by each heating resistor in the specified area is of opposite polarity.

  “Watt density” is defined as a value obtained by dividing the amount of Joule heat generated by a current flowing through a heating resistor element by the area of the heating resistor element. The “polarity of the temperature gradient” means the polarity (different between positive and negative) of the temperature difference at two different points (end points) that are separated in the designated direction of the designated area.

  That is, while the temperature distribution formed by one heating resistor or its maximum value increases continuously or intermittently in the specified direction, the temperature distribution formed by the other heating resistor or its maximum value is Decreases continuously or intermittently in the specified direction.

  For this reason, a flat or uniform total temperature distribution is formed by controlling the temperature gradient formed by each heating resistor in the designated direction in the designated area of the placement surface to the same extent. Further, the temperature gradient formed by the one heating resistor is controlled so that the temperature gradient formed by one heating resistor is steeper than the temperature gradient formed by the other heating resistor. A strongly reflected total temperature distribution is formed. As described above, the temperature distribution as a result of combining the temperature distribution having a gradient in the designated direction formed by each heating resistor is controlled in various forms, thereby improving the control accuracy of the temperature distribution on the mounting surface. Improvement is achieved.

  In the ceramic heater of the present invention, using the size t of the base body in the normal direction of the mounting surface, the distance between each of the first heating resistor and the second heating resistor and the mounting surface is It is preferably 0.4 t or more.

  According to the ceramic heater of the said structure, the influence of the spatial distribution aspect about the designated direction of each heating resistor with respect to the temperature distribution aspect about the designated direction in a mounting surface is reduced.

  In the ceramic heater of the present invention, among the first heating resistor and the second heating resistor, the specified direction of the heating resistor having a longer interval from the mounting surface with respect to the normal direction of the mounting surface. More preferably, the polarity of the temperature gradient for is positive.

  According to the ceramic heater having the configuration, the influence of the spatial distribution mode in the designated direction on the temperature distribution in the designated direction on the mounting surface of the heating resistor having a positive temperature gradient polarity in the designated direction. Can be small.

The first heating resistor is adjacent to the first heating resistor element disposed in each of a plurality of first annular sections spaced from each other so as to overlap the reference point on the placement surface. And a first connecting element that connects the first heating resistors arranged in one annular section, and the second heating resistors overlap each other around the reference point on the placement surface. A second connecting element for connecting the second heating resistor element disposed in each of the plurality of second annular sections spaced apart from each other and the second heating resistor element disposed in the adjacent second annular section. And the first heating resistance element is disposed in the first annular section away from the reference point, with the direction from the reference point toward the outer edge of the mounting surface as the designated direction. So that the watt density is higher While being made, by the second heat generating resistor elements, watt density as being disposed in the second annular zone that is remote from the reference point is configured to be lower, the heating resistors The temperature distribution of the mounting surface is controlled by various forms of the temperature distribution as a result of the synthesis of the temperature distribution having a gradient in the direction from the reference point of the mounting surface toward the outer edge formed by The accuracy is improved.

  In the ceramic heater of the present invention, the first heating resistor and the second heating resistor are arranged so that a part or all of the second annular section overlaps a gap between the adjacent first annular sections. It is preferable.

  According to the ceramic heater having the configuration, the temperature distribution is controlled by reducing or eliminating the area where the first and second heating resistors do not exist in the normal direction on the mounting surface, that is, by controlling the electric power for each heating resistor. The expansion of the range that can be done is intended. For this reason, the accuracy improvement of the temperature distribution control in the said mounting surface is achieved.

The watt density of the first connection element is lower than the watt density of the first heating resistance element, and the watt density of the second connection element is lower than the watt density of the second heating resistance element. Of the surface, a location where the first connection element exists in a gap between the plurality of first annular sections (specific phase zone) and a location where the second connection element exists in the gap between the plurality of second annular sections are locally A situation where the temperature becomes high and it is difficult to control the temperature distribution on the mounting surface can be avoided.

  In the ceramic heater of the present invention, it is preferable that the first heating resistor and the second heating resistor are arranged so that the first connection element and the second connection element do not overlap.

  According to the ceramic heater of the said structure, since the area where the 1st connection element and the 2nd connection element have overlapped exists, the said area becomes excessively higher than the circumference | surroundings on a mounting surface, and control of temperature distribution The situation where it becomes difficult is avoided.

A ceramic heater according to a second aspect of the present invention is a first heating resistor made of a ceramic sintered body and embedded in the base so as not to short-circuit each other with a base having a mounting surface on which a semiconductor wafer is mounted. A designated area in which the existence ranges of the first heating resistor and the second heating resistor overlap with each other in the normal direction of the mounting surface. The first heating resistor and the second heating resistor are arranged so that the watt density distribution modes of the first heating resistor and the second heating resistor are different in the designated area. The gradient polarity of the watt density in the specified direction parallel to the mounting surface of each of the first heating resistor and the second heating resistor in the specified area is reversed, The first heating resistor is disposed adjacent to the first heating resistor element disposed in each of the plurality of first annular sections spaced from each other so as to overlap the reference point on the placement surface. And a first connecting element that connects the first heating resistors arranged in one annular section, and the second heating resistors overlap each other around the reference point on the placement surface. A second connecting element for connecting the second heating resistor element disposed in each of the plurality of second annular sections spaced apart from each other and the second heating resistor element disposed in the adjacent second annular section. And the first heating resistance element is disposed in the first annular section away from the reference point, with the direction from the reference point toward the outer edge of the mounting surface as the designated direction. So that the watt density is higher While being made, the second heat generating resistor elements, watt density as being disposed in the second annular zone that is remote from the reference point is configured to be lower, furthest disposed from the reference point The first heating resistor element is annular and connected to each of a pair of first terminals for supplying power to the first heating resistor via the pair of first connection elements; Alternatively or additionally, a pair of second terminals for supplying electric power to the second heating resistor, and the second heating resistor element disposed farthest from the reference point is annular. wherein the of being connected via a pair of the second connection element respectively.

  According to the ceramic heater having the above configuration, the outermost annular i-th heating resistance element ("i" is one or both of "1" and "2") is parallel to the pair of i-terminals. A pair of connected heating resistance elements are configured. For this reason, the increase in the watt density due to the narrowing of the cross-sectional area or width of the i-th heating resistance element on the outermost side is suppressed. As a result, it is possible to improve the control accuracy of the temperature distribution on the placement surface while saving the arrangement space of the i-th heating resistor.

A ceramic heater according to a third aspect of the present invention is a first heating resistor that is made of a ceramic sintered body and has a mounting surface on which a semiconductor wafer is mounted and is embedded in the base so as not to short-circuit each other. A designated area in which the existence ranges of the first heating resistor and the second heating resistor overlap with each other in the normal direction of the mounting surface. The first heating resistor and the second heating resistor are arranged so that the watt density distribution modes of the first heating resistor and the second heating resistor are different in the designated area. is configured, the substrate is configured to be supported by said support in a state of being bonded to the support on the opposite side of the mounting surface, before the bonding area between the support and the base The degree of overlap between the first heat generating resistor and the second heat generating resistor is higher than the degree of overlap between the first heat generating resistor and the second heat generating resistor in an area different from the junction area. characterized in that the first heating resistor and the second heating resistor is disposed.

  According to the ceramic heater of the said structure, the temperature fall of both joining area | regions by heat transferring from a base | substrate to a support body can be suppressed. Thus, the accuracy of the temperature distribution control can be improved by reducing the influence of heat transfer from the substrate to the support on the temperature distribution of the mounting surface.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the ceramic heater as 1st Embodiment of this invention. II-II sectional view taken on the line of FIG. Explanatory drawing regarding the annular area which defines the arrangement | positioning range of a heating resistive element. Functional explanatory drawing of the ceramic heater as a 1st embodiment of the present invention. Structure explanatory drawing of the ceramic heater as 2nd Embodiment of this invention. Structure explanatory drawing of the ceramic heater as 3rd Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the ceramic heater of the Example and comparative example of this invention. Functional explanatory drawing of the ceramic heater of the Example of this invention, and a comparative example.

(First embodiment)
(Constitution)
The ceramic heater according to the first embodiment of the present invention shown in FIG. 1 includes a substantially disc-shaped base 10 and a first heating resistor R ₁ (one point) embedded in the base 10 so as not to short-circuit each other. And a second heating resistor R ₂ (see the two-dot chain line). The ceramic heater has a pair of first terminals T ₁ for supplying power to the first heating resistor R ₁ and a pair of second terminals for supplying power to the second heating resistor R ₂ . T ₂ is further provided.

The substrate 10 is made of, for example, a sintered body of aluminum nitride to which yttrium oxide is added as a sintering aid. In addition to the first heating resistor R ₁ and the second heating resistor R ₂ , the substrate 10 includes an electrostatic chuck electrode for attracting the semiconductor wafer to the mounting surface 11 by the Johnsen-Rahbek force, and plasma above the substrate 10. At least one of the plasma electrodes for generating the gas may be embedded.

As shown in FIG. 2, one end face (plane) of the base 10 constitutes a placement surface 11 on which an object (not shown) such as a semiconductor wafer is placed. The distance (depth) between the first heating resistor R ₁ and the placement surface 11 is shorter than the distance between the second heating resistor R ₂ and the placement surface 11.

The base body 10 is supported by a substantially cylindrical support body 20 joined to the base body 10 at an end surface 12 opposite to the mounting surface 11. In FIG. 1, a region S ₀ surrounded by two broken-line circles having different diameters corresponds to a joint region between the base 10 and the support 20. The support 20 is made of, for example, an aluminum nitride sintered body. The support 20 may be a component of a ceramic heater. The hollow portion of the support 20 has a first power supply line or rod 21 for connecting each of the pair of first terminals T ₁ and a first external power source (not shown), and each of the pair of second terminals T ₂ . And a second feed line or rod 22 for connecting the second external power source (not shown).

As shown in FIG. 3, when the substrate 10 faces the substrate 10 in the normal direction of the mounting surface 11, the mounting surface is separated from each other in the radial direction (or the latitudinal direction). Annular first annular sections S _{11 to} S ₁₅ extending in the circumferential direction (or longitude direction) surrounding 11 center points (reference points) O are defined. The existence range of the first heating resistor R ₁ is defined by an inner arc of the innermost first annular section S ₁₁ and an outer arc of the outermost first annular section S ₁₅ .

When the radius of the base 10 is R, each first annular section is viewed from the inside due to a radial component in a circular coordinate system (a polar coordinate system in the two-dimensional Euclidean space R ² ) whose origin is the center point O of the mounting surface 11 [Α ₁₁ R, (α ₁₁ + δ ₁₁ ) R], [α ₁₂ R, (α ₁₂ + δ ₁₂ ) R], [α ₁₃ R, (α ₁₃ + δ ₁₃ ) R], [α ₁₄ R, (α ₁₄ + δ ₁₄ ) R] and [α ₁₅ R, (α ₁₅ + δ ₁₅ ) R]. Here, there is a relationship represented by the inequality (01) between the coefficients.

0 <α ₁₁ <α ₁₁ + δ ₁₁ <α ₁₂ <α ₁₂ + δ ₁₂ <α ₁₃ <α ₁₃ + δ ₁₃ <α ₁₄ <α ₁₄ + δ ₁₄ <α ₁₅ <α ₁₅ + δ ₁₅ <1 (01).

The first heating resistor R ₁ is made of a refractory metal such as molybdenum or tungsten or a conductor containing the metal as a main component. First heating resistor R ₁ is the first connection element C ₁₁ -C ₁₄ respectively connecting the arrangement to the first heating resistor elements R ₁₁ to R ₁₅ and are these first annular section S ₁₁ to S ₁₅ It is configured. Each of the first heating resistance elements R _{11 to} R ₁₄ is configured by a pair of substantially semicircular arc heating resistance elements spaced apart from each other. The outermost first heating resistor element R ₁₅ is constituted by a single substantially annular heating resistor element.

Each of the pair of heat generation resistance elements constituting the first heat generation resistance element R _1j (j = 1 to 3) is adjacent to the first heat generation resistance element R _1j spaced apart radially outward via the pair of first connection elements C _1j . One heating resistance element R _{1j + 1} is connected to each of a pair of heating resistance elements.

Each of the pair of heating resistance elements constituting the first heating resistance element R ₁₄ is the outermost first heating resistance element adjacent to each other in the radial direction via the pair of first connection elements C _14. It is connected to a single heating resistor element constituting R ₁₅ . The outermost first heating resistor element R ₁₅ is arranged in parallel between the pair of first terminals T ₁ , more precisely between each of the pair of heating resistor elements constituting the inner first heating resistor element R _14. A pair of connected heating resistance elements are configured.

Each of the pair of first connection elements C _{11 to} C ₁₄ is arranged with a phase shifted by about π. Each of the first connection element C ₁₁ -C _14, are at least partially shape wider than the width of each of the δ ₁₁ ~δ ₁₅ of the first heat generating resistor elements R ₁₁ to R ₁₅ (e.g. 3Deruta ₁₁ or more) Yes.

As shown in FIG. 3, the base body 10 has annular second annular sections S _{21 to} S ₂₄ that overlap with the center point O of the mounting surface 11 while being spaced apart from each other in the radial direction. Further defined. The existence range of the second heating resistor R ₂ is defined by an inner arc of the innermost second annular section S ₂₁ and an outer arc of the outermost second annular section S ₂₄ . In the present embodiment, the overlapping range (designated area) of the existence range of the second heating resistor R _{1 and} the existence range of the second heating resistor R ₂ coincides with the existence range of the second heating resistor R ₂ .

When the radius of the base 10 is R, each second annular section is sequentially [α ₂₁ R, (α ₂₁ + δ ₂₁₎ from the inside due to the radial component in the circular coordinate system with the center point O of the mounting surface 11 as the origin. ) R], [α ₂₂ R, (α ₂₂ + δ ₂₂ ) R], [α ₂₃ R, (α ₂₃ + δ ₂₃ ) R] and [α ₂₄ R, (α ₂₄ + δ ₂₄ ) R]. . The second annular section S _2k (k = 1 to 4) is arranged so as to overlap the gap between the adjacent first annular sections S _1k and S _{1k + 1} . That is, there is a relationship represented by the inequality (02) between the coefficients.

α ₁₁ + δ ₁₁ <α ₂₁ <α ₂₁ + δ ₂₁ <α ₁₂ , α ₁₂ + δ ₁₂ <α ₂₂ <α ₂₂ + δ ₂₂ <α ₁₃ , α ₁₃ + δ ₁₃ <α ₂₃ <α ₂₃ + δ ₂₃ <α ₁₄ , α ₁₄ + Δ ₁₄ <α ₂₄ <α ₂₄ + δ ₂₄ <α ₁₅ (02).

The second heating resistor R ₂ is made of a refractory metal such as molybdenum or tungsten or a conductor containing the metal as a main component, like the first heating resistor R ₁ . Second heating resistor R ₂ is a second annular zone S ₂₁ second connecting element C ₂₁ -C ₂₃ connecting disposed second heating resistor elements R ₂₁ and to R ₂₄ and these each to S ₂₄ It is configured. Each of the second heating resistance elements R _{21 to} R ₂₃ is composed of a pair of heating resistance elements having a substantially semicircular arc shape spaced apart from each other. The outermost second heating resistor element R ₂₄ is composed of a single substantially annular heating resistor element.

Each of the pair of heating resistance elements constituting the second heating resistance element R _1j (j = 1, 2) is adjacent to the second heating element R _2j adjacent to the outer side in the radial direction via the pair of second connection elements C _2j . The two heating resistance elements R _{2j + 1} are connected to each of a pair of heating resistance elements.

Each of the pair of heating resistive elements that configure the second heat generating resistive elements R _23, via a respective pair of second connection element C _23, a second heating resistor elements of the outermost adjacent spaced radially outward It is connected to a single heating resistor elements constituting the R _24. The outermost second heating resistance element R ₂₄ is between the pair of second terminals T ₂ , more precisely, between each of the pair of heating resistance elements constituting the inner second heating resistance element R ₂₃ . A pair of heating resistance elements connected in parallel is configured.

Each of the pair of second connection elements C _{21 to} C ₂₃ is arranged with a phase shifted by about π. Each of the second connection elements C _{21 to} C ₂₃ is arranged with a phase shifted by about π / 4 from each of the first connection elements C _{11 to} C ₁₄ . Each of the second connecting element C ₂₁ -C _23, are at least partially shape wider than the width of each of the δ ₂₁ ~δ ₂₄ of the second heating resistor elements R ₂₁ to R ₂₄ (e.g. 3Deruta ₂₄ or more) Yes.

Each of the first heating resistance elements R _{11 to} R ₁₅ is configured such that the watt density increases as the first heating resistance elements R _{11 to} R ₁₅ are arranged in the first annular section that is separated from the center point from the reference point radially outward. Specifically, there is a relationship between the line widths δ ₁₁ ~δ ₁₅ of the first heat generating resistor elements R ₁₁ to R ₁₅ represented by the inequality (03).

0.5δ ₁₅ <δ ₁₄ <δ ₁₃ <δ ₁₂ <δ ₁₁ (03).

In inequality (03), only δ ₁₅ is multiplied by “0.5” because the outermost first heating resistance element R ₁₅ is parallel between the pair of first connection elements C ₁₄ as described above. This is for constituting a pair of connected heating resistance elements.

Each of the second heating resistance elements R _{21 to} R ₂₄ is configured such that the watt density decreases as the second heating resistance elements R _{21 to} R ₂₄ are arranged in the second annular section that is distant from the center point from the reference point radially outward. Specifically, there is a relationship between the line widths δ ₂₁ ~δ ₂₄ of the second heating resistor elements R ₂₁ to R ₂₄ represented by the inequality (04).

δ ₂₁ <δ ₂₂ <δ ₂₃ <0.5 δ ₂₄ (04).

In the inequality (04), only δ ₂₄ is multiplied by “0.5” because the outermost second heating resistance element R ₂₄ is parallel between the pair of second connection elements C ₂₃ as described above. This is for constituting a pair of connected heating resistance elements.

(Manufacturing method 1)
A raw material powder in which 5% by weight of yttrium oxide powder is added to a high-purity aluminum nitride powder is mixed with a solvent (IPA) by a ball mill and dried, and then a powder obtained as a raw material powder is prepared. It was. Mo foil having a predetermined shape (for example, a thickness of 0.1 [mm]) was prepared as each of the first heating resistor R ₁ and the second heating resistor R ₂ .

Raw material powder, is pressed on charged into the cylindrical mold space formed in the mold made of carbon, thereby the (center second heating resistor R ₂ is concentrically on the obtained molded article To match). Further, the raw material powder was pressed after a predetermined amount was put into the mold space. Further, the raw material powder was pressed into the mold space and pressed, and the first heating resistor R ₁ was placed concentrically on the resulting molded body. The raw material powder was further put into the mold space from above and pressed. As a result, a molded body in which the first heating resistor R ₁ and the second heating resistor R ₂ were embedded was obtained.

The input amount of the raw material powder into the mold space is appropriately adjusted according to the respective embedding positions of the first heating resistor R ₁ and the second heating resistor R ₂ in the ceramic heater obtained by sintering the molded body. (See FIGS. 1 and 2).

  Then, the compact was sintered by a hot press sintering method. That is, it was maintained at a high temperature in a non-oxidizing atmosphere such as nitrogen under a predetermined pressure in the axial direction of the mold space. A ceramic heater was manufactured by shaping the sintered body thus obtained by grinding.

(Manufacturing method 2)
The first heating resistor R ₁ and the second heating resistor R ₂ and the three raw material powder compacts sandwiched between them are hot pressed and sintered together to form a static electricity with a heater. A chuck may be manufactured.

  A raw material powder in which 5% by weight of yttrium oxide powder is added to high-purity aluminum nitride powder is mixed by a ball mill together with a binder, a dispersant and a solvent (IPA), and a slurry is prepared from this slurry. The granules obtained by the above were prepared as raw powder.

  By grinding the raw material powder after CIP molding, three substantially disk-shaped molded bodies having the same diameter R were produced, and each of the molded bodies was degreased. Mo foil (for example, thickness 0.1 [mm]) was prepared as each of the electrostatic chuck electrode and the heating resistor.

In addition, a molded body, a first heating resistor R ₁ , a molded body, a second heating resistor R _2, and a molded body are stacked in that order from the bottom in a cylindrical mold space formed in the carbon mold. To be installed concentrically. The molded body may be produced by casting.

  Then, the compacts and the like stacked concentrically were sintered by a hot press sintering method. A ceramic heater was manufactured by shaping the sintered body thus obtained by grinding.

In the normal direction of the mounting surface 11 of the obtained ceramic heater, the size t of the base 10 is 20 [mm], the distance between the first heating resistor R ₁ and the mounting surface 11 is 8 [mm], and the second The distance between the heating resistor R ₂ and the mounting surface 11 was 16 [mm].

(function)
FIG. 4 (a), when the supply power W ₂ for the first heating resistor R ₁ to the power W ₁ and the second heating resistor R ₂ are the same, the temperature distribution formed in the radial direction of the base 10 Is shown as a solid line. A temperature gradient formed by the first heating resistor R ₁ is indicated by a one-dot chain line, and a temperature gradient formed by the second heating resistor R ₂ is indicated by a two-dot chain line. Figure 4 (b), the temperature of the power W ₁ for the first heating resistor R ₁ are formed in the radial direction of the base 10 when it is controlled higher than the supply power W ₂ to the second heating resistor R ₂ The distribution is shown as a solid line. 4 The (c), the temperature of the power W ₁ for the first heating resistor R ₁ are formed in the radial direction of the base 10 when it is controlled to be lower than the supply power W ₂ to the second heating resistor R ₂ The distribution is shown as a solid line.

Figure 4 (a), placing the second heating resistor R area containing the existing range of ₂ (designated area) of the surface 11, the temperature gradient comparable formed by the heating resistors in the radial direction (designated direction) It can be seen that a flat or uniform temperature distribution is formed by the control. Further, from FIGS. 4B and 4C, the temperature gradient formed by one heating resistor is controlled to be steeper than the temperature gradient formed by the other heating resistor. It can be seen that a temperature distribution that strongly reflects the temperature gradient formed by the heating resistor is formed.

  As described above, the temperature distribution as a result of combining the temperature distribution having the gradient in the designated direction formed by each heating resistor is controlled in various forms, so that the control accuracy of the temperature distribution of the mounting surface 11 is controlled. Is improved.

(Second Embodiment)
(Constitution)
The ceramic heater as the second embodiment of the present invention is obtained by substantially the same manufacturing method as the ceramic heater according to the first embodiment of the present invention, and the configuration is also substantially the same, so the description of the common configuration is omitted. To do. In the ceramic heater as the second embodiment of the present invention, as shown in FIG. 5, the innermost first heating resistance element R ₁₁ and the second innermost region in the joint area S ₀ between the base 10 and the support 20 are shown. It is arranged so as heating resistor elements R ₂₁ are overlapped. That is, as the overlap of the first heating resistor in the junction area S ₀ R ₁ and the second heating resistor R ₂ is higher than that in another area and that the first heating resistor R ₁ The second heating resistor R ₂ is disposed.

(function)
According to the ceramic heater of the structure, due to the fact that the body 10 heat is transferred to the support 20, the temperature drop of the bonding area S ₀ of both can be suppressed. Thus, the accuracy of the temperature distribution control can be further improved by reducing the influence of heat transfer from the substrate to the support on the temperature distribution of the mounting surface 11.

(Other embodiments)
Substrate 10, respective shapes and arrangement of the like first heating resistor R ₁ and the second heating resistor R ₂ may be variously changed. For example, the outermost first heating resistor element R ₁₅ (see FIG. 1) has a single arc shape (semi-arc shape) in which the other heating resistor elements are connected in series between the pair of first terminals T ₁ . You may be comprised by the heating resistance element. Alternatively or in addition, the outermost second heating resistor element R ₂₄ is connected in series with another heating resistor element between the pair of second terminals T ₂ (a semicircular arc shape). The heating resistance element may be used.

Further, as shown in FIG. 6, the base 10 is formed in a substantially rectangular plate shape, and the shape and arrangement of each of the first heating resistor R ₁ and the second heating resistor R ₂ are designed accordingly. May be. For the sake of explanation, an x-axis and a y-axis are defined in parallel with each of two orthogonal sides of the substrate 10.

In the ceramic heater shown in FIG. 6A, each of the first heating resistor R ₁ (see solid line) and the second heating resistor R ₂ (see broken line) is in the + x direction (right direction in the figure). After extending, the meandering pattern is repeated such that the meandering pattern is folded back to a location shifted in the + y direction (upward in the figure) and extended in the −x direction. Each of the six linear or strip-like portions extending horizontally in the x-axis of the first heating resistor R ₁ constitutes a first heating resistor element. Each of the six linear or strip-like portions extending horizontally in the x-axis of the second heating resistor R ₂ constitutes a second heating resistor element.

In the ceramic heater shown in FIG. 6B, each of the first heating resistor R ₁ (see the solid line) and the second heating resistor R ₂ (see the broken line) seems to be repeatedly zigzag-shaped. It is a simple shape. Each of the five linear or strip-like portions of the first heating resistor R ₁ constitutes a first heating resistor element. Each of the five linear or strip-like portions of the second heating resistor R ₂ constitutes a second heating resistor element.

  6 (a) and 6 (b), the second area where the second heating resistance element is arranged overlaps with the gap between the first areas where the first heating resistance element is arranged. ing. The first heating resistance element is configured such that the watt density increases as the y-coordinate value indicating the position increases (the higher the position is in the figure). On the other hand, the second heating resistance element is configured such that the watt density decreases as the y coordinate value indicating the position increases.

  According to the ceramic heater of the said structure, the temperature distribution of a mounting surface is a desired form about + y direction as a designated direction by controlling the combination of each electric power of a 1st heating resistor and a 2nd heating resistor. Can be controlled with high accuracy (see FIGS. 4A to 4C).

An interval β ₁ t (0 <β ₁ <1) from the mounting surface 11 of the first heating resistor R ₁ in the base 10 having a thickness t and an interval from the mounting surface 11 of the second heating resistor R _2. By changing β ₂ t (0 <β ₂ ≠ β ₁ <1), the temperature distribution of the mounting surface 11 in the specified direction may be controlled.

For example, by adjusting both the intervals β ₁ t and β ₂ t to be relatively short (for example, 0.15 ≦ β ₁ <β ₂ ≦ 0.40), the first heating resistor R ₁ and the second heating resistor The shape of the watt density distribution curve in each designated direction of the body R ₂ can be reflected relatively clearly in the shape of the temperature distribution curve in the designated direction on the placement surface 11 (one point in FIG. 4A). (See chain line and two-dot chain line).

On the other hand, by adjusting both of the intervals β ₁ t and β ₂ t to be relatively long (for example, 0.40 ≦ β ₁ <β ₂ ≦ 0.85), the first heating resistor R ₁ and the second heat generation are performed. The shape of the watt density distribution curve in each specified direction of the resistor R ₂ can be reflected relatively blurringly in the shape of the temperature distribution curve in the specified direction on the mounting surface 11 (FIG. 4B). (See the two-dot chain line and the one-dot chain line in FIG. 4C).

(Experimental result)
As the ceramic heater of Example 1, as shown in FIG. 7A, the circular central region A ₁ defined in the substantially disk-shaped substrate 10 and the radial direction surrounding this are overlapped with each other. Among the four annular regions A _{2 to} A ₅ that are separated from each other, one or a plurality of first heat generations that constitute a single first heat generation resistor R ₁ in each of the regions A ₁ , A _3, and A ₅ While the resistance elements are arranged, a configuration in which one or a plurality of second heating resistance elements constituting the single second heating resistance R ₂ is arranged in each of the regions A ₂ and A ₄ is adopted. .

As the ceramic heater of Example 2, as shown in FIG. 7B, the circular central region A ₁ defined in the base 10 and the radial direction surrounding the same are overlapped with each other in the radial direction. Of the two annular regions A ₂ and A ₃ , one or a plurality of first heating resistor elements constituting a single first heating resistor R ₁ are arranged in each of the regions A ₁ and A ₃ . On the other hand, a configuration is adopted in which one or a plurality of second heating resistor elements constituting the single second heating resistor R ₂ are arranged in the region A ₂ .

As a ceramic heater of the comparative example, as shown in FIG. 7C, among the circular central region A ₁ defined in the substrate 10 and the annular region A ₂ surrounding it, the region A ₁ One or more first heating resistors R ₁ constituting the single first heating resistor R ₁ are arranged, while one or more of the first second heating resistors R ₂ constituting the single second heating resistor R ₂ are arranged in the region A ₂ . A configuration in which the second heating resistance element is arranged is adopted. In the ceramic heater of the comparative example, unlike the ceramic heaters of Examples 1 and 2, the existence ranges of the first heating resistor R ₁ and the second heating resistor R ₂ do not overlap.

FIG. 8 shows the mounting surfaces in the radial directions of Example 1, Example 2, and Comparative Example in the cases where the power supplied to the first heating resistor R ₁ and the second heating resistor R ₂ is different. The temperature distribution measurement results are shown by a one-dot chain line, a two-dot chain line, and a broken line, respectively. FIG. 8A shows the measurement results when the power supplied to each of the first heating resistor R ₁ and the second heating resistor R ₂ is controlled to 2200 [W]. FIG. 8B shows the measurement results when the power supplied to each of the first heating resistor R ₁ and the second heating resistor R ₂ is controlled to 1350 [W].

  When the power supplied to each heating resistor is controlled to 2200 [W], the difference between the maximum temperature and the minimum temperature of the mounting surface is 9.8 [° C.] in the comparative example, while the first embodiment is different. Was 2.5 [° C.] and 6.4 [° C.] in Example 2 (see FIG. 8A). When the power supplied to each heating resistor is controlled to 1350 [W], the difference between the maximum temperature and the minimum temperature of the mounting surface is 4.9 [° C.] in the comparative example, whereas Example 1 Was lower than 0.9 [° C.] and 3.5 [° C.] in Example 2 (see FIG. 8B).

10 ‥ base, 20 ‥ support, R ₁ ‥ first heating resistor, R ₂ ‥ second heating resistor.

Claims (7)

A base made of a ceramic sintered body and having a mounting surface on which a semiconductor wafer is placed; and a first heating resistor and a second heating resistor embedded in the base so as not to short-circuit each other A ceramic heater,
The first heating resistor and the second heating resistor are arranged so that there is a designated area where the existence ranges of the first heating resistor and the second heating resistor overlap in the normal direction of the mounting surface. Arranged in the designated area, the watt density distribution mode of the first heating resistor and the second heating resistor are different from each other ,
The watt density gradient polarity of each of the first heating resistor and the second heating resistor in the specified area in the specified direction parallel to the mounting surface is opposite,
The first heating resistor is adjacent to the first heating resistor element disposed in each of a plurality of first annular sections spaced from each other so as to overlap the reference point on the placement surface. And a first connecting element that connects the first heating resistors arranged in one annular section, and the second heating resistors overlap each other around the reference point on the placement surface. A second connecting element for connecting the second heating resistor element disposed in each of the plurality of second annular sections spaced apart from each other and the second heating resistor element disposed in the adjacent second annular section. And
The watt density increases as the first heating resistance element is arranged in the first annular section away from the reference point with the direction from the reference point toward the outer edge of the mounting surface as the designated direction. On the other hand, the second heating resistance element is configured such that the watt density decreases as the second heating resistance element is disposed in the second annular section away from the reference point.
The watt density of the first connection element is lower than the watt density of the first heating resistance element, and the watt density of the second connection element is lower than the watt density of the second heating resistance element. Ceramic heater. A base made of a ceramic sintered body and having a mounting surface on which a semiconductor wafer is placed; and a first heating resistor and a second heating resistor embedded in the base so as not to short-circuit each other A ceramic heater,
The first heating resistor and the second heating resistor are arranged so that there is a designated area where the existence ranges of the first heating resistor and the second heating resistor overlap in the normal direction of the mounting surface. Arranged in the designated area, the watt density distribution mode of the first heating resistor and the second heating resistor are different from each other,
The watt density gradient polarity of each of the first heating resistor and the second heating resistor in the specified area in the specified direction parallel to the mounting surface is opposite,
The first heating resistor is adjacent to the first heating resistor element disposed in each of a plurality of first annular sections spaced from each other so as to overlap the reference point on the placement surface. And a first connecting element that connects the first heating resistors arranged in one annular section, and the second heating resistors overlap each other around the reference point on the placement surface. A second connecting element for connecting the second heating resistor element disposed in each of the plurality of second annular sections spaced apart from each other and the second heating resistor element disposed in the adjacent second annular section. And
The watt density increases as the first heating resistance element is arranged in the first annular section away from the reference point with the direction from the reference point toward the outer edge of the mounting surface as the designated direction. On the other hand, the second heating resistance element is configured such that the watt density decreases as the second heating resistance element is disposed in the second annular section away from the reference point.
The first heating resistor element disposed farthest from the reference point is annular, and a pair of first terminals is connected to each of a pair of first terminals for supplying power to the first heating resistor. Connected via a connecting element, instead of or in addition, the second heating resistor element arranged farthest from the reference point is annular and supplies power to the second heating resistor A ceramic heater, wherein the ceramic heater is connected to each of a pair of second terminals through a pair of second connection elements . The ceramic heater according to claim 1 or 2 ,
The distance between each of the first heating resistor and the second heating resistor and the mounting surface is 0.4 t or more using the size t of the base body in the normal direction of the mounting surface. Ceramic heater characterized by In the ceramic heater according to any one of claims 1 to 3 ,
Of the first heating resistor and the second heating resistor, the polarity of the temperature gradient in the specified direction of the heating resistor having the longer interval from the mounting surface in the normal direction of the mounting surface is Ceramic heater characterized by being positive. In the ceramic heater according to any one of claims 1 to 4 ,
The ceramic heater, wherein the first heating resistor and the second heating resistor are arranged so that a part or all of the second annular zone overlaps a gap between the adjacent first annular zones. . In the ceramic heater according to any one of claims 1 to 5 ,
The ceramic heater, wherein the first heating resistor and the second heating resistor are arranged so that the first connection element and the second connection element do not overlap. A base made of a ceramic sintered body and having a mounting surface on which a semiconductor wafer is placed; and a first heating resistor and a second heating resistor embedded in the base so as not to short-circuit each other A ceramic heater,
The first heating resistor and the second heating resistor are arranged so that there is a designated area where the existence ranges of the first heating resistor and the second heating resistor overlap in the normal direction of the mounting surface. Arranged in the designated area, the watt density distribution mode of the first heating resistor and the second heating resistor are different from each other ,
The base is configured to be supported by the support in a state of being bonded to the support on the opposite side of the placement surface,
The degree of overlap between the first heating resistor and the second heating resistor in the joint area between the base and the support is such that the first heating resistor and the second heat generation in an area other than the joint area. The ceramic heater , wherein the first heating resistor and the second heating resistor are arranged so as to be higher than an overlapping degree with the resistor .