JP2017076691A - Ceramic heater and electrostatic chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic heater and an electrostatic chuck which allow for partial temperature control in the plane direction.SOLUTION: In the ceramic heater 5 of an electrostatic chuck 1, a resistive heating element 11 (partial heating elements 51-57) is sectioned into multiple partial resistors by an intermediate sub-terminal 29 connected between electric paths connecting main terminals 27. Furthermore, between at least a pair of terminals 21 out of the terminals 21 consisting of the main terminals 27 and sub-terminals 29, an auxiliary resistor 65 is connected electrically in parallel with the partial resistor. Consequently, even if the value of resistance of respective partial resistors is different, calorific value of respective partial resistors can be made uniform, by adjusting the value of resistance of the auxiliary resistor 65 arranged in parallel with the partial resistor (by using an auxiliary resistor 65 of proper value of resistance).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a ceramic heater that can heat a workpiece such as a semiconductor wafer, and an electrostatic chuck including the ceramic heater.

  Conventionally, in a semiconductor manufacturing apparatus, a process such as dry etching (for example, plasma etching) is performed on a semiconductor wafer (for example, a silicon wafer). In order to increase the accuracy of this dry etching, it is necessary to securely fix the semiconductor wafer. Therefore, an electrostatic chuck for fixing the semiconductor wafer by electrostatic attraction has been proposed as a fixing means for fixing the semiconductor wafer. Yes.

  Specifically, an electrostatic chuck has, for example, an adsorption electrode inside a ceramic substrate, and a semiconductor wafer is bonded to the ceramic substrate using electrostatic attraction generated when a voltage is applied to the adsorption electrode. It is made to adsorb | suck to the upper surface (1st main surface: adsorption surface). This electrostatic chuck is configured by bonding a metal base to a lower surface (second main surface: bonding surface) of a ceramic substrate.

  Furthermore, an electrostatic chuck having a function of adjusting (heating or cooling) the temperature of the semiconductor wafer attracted to the attracting surface is also known. For example, a technique for heating a semiconductor wafer on an adsorption surface by arranging a heating element (for example, a linear heating pattern) in a ceramic substrate and heating the ceramic substrate with the heating element is also known. There is also known a technique in which a cooling path for flowing a cooling fluid is provided in a metal base, and the ceramic substrate is cooled by the cooling fluid.

  In recent years, ceramic heaters in which a ceramic substrate is divided into a plurality of heating zones have been developed in order to precisely heat the electrostatic chuck. Specifically, a ceramic heater with a multi-zone heater in which a heating element (partial heating element) capable of independently heating each heating zone is arranged for each heating zone to improve the temperature adjustment function of the ceramic substrate. Has also been proposed (see Patent Documents 1 and 2).

  As this ceramic heater with a multi-zone heater, for example, as shown in FIG. 11A, an annular heating zone (circumferential zone) P1 is concentrically arranged. In the circumferential zone P1, the heating element P2 is arranged in a circular shape, for example, and both ends thereof are connected to two terminals P3.

  In addition, this type of heating element P2 is formed by, for example, printing (heater printing) a heater paste, which is a heating element material, on the surface of, for example, a ceramic sheet that is a material constituting the ceramic substrate.

JP 2002-93677 A JP 2005-166354 A

  However, in the case where the heating element P2 is formed by heater printing as described above, as shown in FIG. 11B, due to variations in the printing thickness, the heating element P2 has a different thickness (for example, a thinner thickness P4). For example, the resistance (resistance value r) of the thin portion P4 is larger than the resistance (resistance value R) of other portions (r> R).

That is, for example, in a ceramic heater with a multi-zone heater provided with the circumferential zone P1, the current (I) flowing through the heating element P2 between the terminals P3 is constant, so that the resistance (resistance value) is partially applied to the heating element P2. If there is a large part), the amount of heat generated at that part will increase. Specifically, since the amount of heat generation is proportional to the resistance (the amount of heat generation per unit time (Q) = resistance × current ² ), the portion where the resistance is large generates more heat than the other portions and the temperature becomes high. As a result, there is a problem that the temperature distribution (in-plane temperature) in the plane direction of the ceramic heater becomes non-uniform.

  In addition to this, there is a demand not only to make the in-plane temperature of the ceramic heater (and hence the electrostatic chuck) uniform, but also to more actively adjust the temperature partially in the plane direction of the ceramic heater and the like. .

  The present invention has been made in view of the above problems, and its purpose is to make the temperature partially in the plane direction, such as uniform temperature distribution in the plane direction of the ceramic heater or changing the temperature at a specific position. It is an object of the present invention to provide an adjustable ceramic heater and electrostatic chuck.

  (1) A ceramic heater according to a first aspect of the present invention includes a ceramic substrate having a first main surface and a second main surface, and a workpiece embedded in the ceramic substrate and disposed on the first main surface. In the ceramic heater comprising a heating element to be heated, the heating element is a resistance heating element that generates heat when energized between a pair of main terminal portions electrically connected to the heating element, The heating element is divided into a plurality of partial resistances each having a resistance value by one or a plurality of sub-terminal portions connected between electrical paths connecting the pair of main terminal portions, and further the pair of main terminal portions. An auxiliary resistor is electrically connected in parallel with the partial resistor between at least one pair of the terminal portions of the terminal portion including the terminal portion and the one or more sub terminal portions.

  In the first aspect, the heating element, which is a resistance heating element, is divided into a plurality of partial resistances by an intermediate sub-terminal part connected between electrical paths connecting the main terminal parts, and further, the main terminal part An auxiliary resistor is electrically connected in parallel with the partial resistor between at least a pair of terminal portions of the terminal portion including the sub-terminal portion.

  Therefore, for example, even when the resistance value of each partial resistor is different, by adjusting the resistance value of the auxiliary resistor arranged in parallel with the partial resistor (that is, by using the auxiliary resistor having an appropriate resistance value), The amount of heat generated per unit area can be adjusted (for example, the amount of heat generated can be made uniform).

  For example, when the heating element is divided into partial resistances for each predetermined region (for example, individual zones), when the heating element is thin in a certain individual zone, the resistance value of the partial resistance in that individual zone is different from that of the individual resistance. It becomes larger than the resistance value of the partial resistance of the zone. As a result, the amount of heat generated by the partial resistance having a large resistance value increases, and the temperature of the individual zone may become higher than the surroundings (that is, the in-plane temperature of the ceramic heater may become uneven).

  Even in such a case, in the first aspect, by using the auxiliary resistance, the amount of heat generated by the partial resistance connected to the auxiliary resistance is reduced, and the temperature of the partial resistance (and hence the heating zone) is excessively increased. By suppressing this, the in-plane temperature of the ceramic heater can be easily made uniform.

  In addition, by using various auxiliary resistors (for example, variable resistors) or adjusting the connection state of the auxiliary resistors (for example, switching the connection state with a switch), not only the in-plane temperature of the ceramic heater is made uniform, It is also possible to adjust the temperature of the region where the partial resistance is disposed (to make a temperature difference from other regions).

For example, when the resistance value of each partial resistor is the same, the amount of heat generated by the specific partial resistor can be reduced by connecting an auxiliary resistor in parallel to the specific partial resistor.
Therefore, in the first aspect, since the temperature at an arbitrary position on the surface of the ceramic heater can be adjusted, there is an advantage that the workability is improved when various kinds of processing are performed on the workpiece.

In addition, the 1st main surface and the 2nd main surface have shown one surface and the other surface (the other side) in the thickness direction of a ceramic substrate.
The main terminal portion is a terminal portion that is electrically connected to both ends of the heating element to supply power to the heating element, and the sub-terminal portion is interposed between the electrical paths (that is, the heating element) between the main terminal portions. It is the terminal part arrange | positioned. The terminal portion is a general term for the main terminal portion and the sub-terminal portion, and is a conductive portion such as a terminal fitting or a conductive portion in a ceramic substrate that is electrically connected to the heating element.

  Furthermore, the partial resistance is a part of the resistance heating element divided by the terminal portion of the resistance heating element, and its resistance value constitutes a part of the total resistance of the resistance heating element. The auxiliary resistor is a resistor having a predetermined resistance value.

  The ceramic heater is a heater provided with at least a heating element inside a ceramic substrate (a substrate made of ceramic or containing ceramic as a main component). In the first aspect, in addition to the heating element, each of the above-described configurations is provided. I have.

(2) In the ceramic heater according to the second aspect of the present invention, the auxiliary resistor is a fixed resistor or a variable resistor.
As an auxiliary resistor, it is exemplified that a fixed resistor or a variable resistor can be adopted.

  (3) In the ceramic heater according to the third aspect of the present invention, when the heating element is viewed from the first main surface side, the heating element is arranged in an annular shape and one or a plurality of the sub-terminal portions. Are divided into a plurality of partial resistances along the circumferential direction of the heating element.

In the third aspect, the heating element is annular, and is illustrated as being divided into a plurality of partial resistances by the sub-terminal portion.
(4) In the ceramic heater according to the fourth aspect of the present invention, when the heating element and the auxiliary resistor are viewed from the first main surface side, an area of a region where a partial resistor to which the auxiliary resistor is connected is formed. The area of the region where the auxiliary resistor is formed is set larger than that.

  When the auxiliary resistor is connected, since the auxiliary resistor generates heat by energizing the auxiliary resistor (usually), the temperature of the region where the auxiliary resistor is disposed easily rises. On the other hand, in the fourth aspect, in the plan view, the region where the auxiliary resistor is formed is larger than the area of the region where the partial resistor to which the auxiliary resistor is connected is formed, so that the temperature of the auxiliary resistor increases. Even so, the temperature of the region where the partial resistance (connected to the auxiliary resistor) is formed is unlikely to rise. Thereby, the in-plane temperature of the ceramic heater can be made more uniform.

(5) The ceramic heater according to the fifth aspect of the present invention includes all the heating elements in which the plurality of heating elements are electrically connected in parallel.
In the fifth aspect, since a plurality of heat generating elements are electrically connected in parallel to form a total heat generating element, for example, the resistance value of all the heat generating elements is reduced as compared with a case where partial heat generating elements are connected in series. Can do.

  (6) In the ceramic heater according to the sixth aspect of the present invention, the ceramic substrate includes a plurality of ceramic layers, and the all heating elements are formed on the same surface of the ceramic layer. The connection part for electrically connecting the two is formed on the surface of the ceramic layer different from the surface.

  In the sixth aspect, a configuration in which a plurality of heating elements (for example, A and B partial heating elements described later) are electrically connected to each other is illustrated, and thus by providing a connection portion on the surface of different ceramic layers. There is an advantage that the degree of freedom of design is improved.

  (7) In the ceramic heater according to the seventh aspect of the present invention, the ceramic substrate is composed of a plurality of ceramic layers, and the all heating elements are formed on the same surface of the ceramic layer. The connecting portion for electrically connecting the two is formed on the same surface as the surface.

  In the seventh aspect, a configuration in which a plurality of heating elements (for example, heating patterns described later) are electrically connected to each other is illustrated, and thus by providing a connection portion on the surface of the same ceramic layer, all heating elements are provided. There is an advantage that it is easy to form.

(8) In the ceramic heater according to the eighth aspect of the present invention, the auxiliary resistor is a fixed resistor, and the fixed resistor further includes a switch for turning on and off a connection circuit.
In the eighth aspect, since the connection state of the auxiliary resistor can be freely set by the switch, the heat generation state of each partial resistor accompanying the connection state of the auxiliary resistor can be easily adjusted. Therefore, there is an advantage that the in-plane temperature can be made uniform and the temperature of the region where each partial resistance is formed can be easily adjusted (for example, the temperature can be different from that of other regions).

  (9) An electrostatic chuck according to a ninth aspect of the present invention is the electrostatic chuck including the ceramic heater according to any one of the first to eighth aspects, and is the electrostatic chuck embedded in the ceramic substrate. An adsorption electrode for adsorbing a workpiece is provided, and a metal base is provided on the second main surface of the ceramic substrate.

In the ninth aspect, an electrostatic chuck including the above-described ceramic heater is illustrated.
(10) The electrostatic chuck according to a tenth aspect of the present invention includes an accommodating portion that accommodates the auxiliary resistor on the side opposite to the second main surface side in the metal base.

  In the tenth aspect, since the accommodating portion that accommodates the auxiliary resistor is provided on the side opposite to the metal-based ceramic heater, the auxiliary resistor is unlikely to become an obstacle when using the electrostatic chuck (for example, in contact with the auxiliary resistor). There is an advantage that it is difficult to cause breakage or dropout.

  (11) The electrostatic chuck according to an eleventh aspect of the present invention has a cooling part capable of cooling the ceramic substrate on the metal base, and the auxiliary resistor on the opposite side of the cooling part from the second main surface side. It has.

  When the auxiliary resistor is energized, the auxiliary resistor normally generates heat. However, in the eleventh aspect, the auxiliary resistor is disposed on the opposite side of the ceramic heater from the cooling unit, so that the temperature rise of the auxiliary resistor is cooled. (Ie, the temperature of the auxiliary resistor is difficult to be transmitted to the ceramic heater side). Thereby, the in-plane temperature of the ceramic heater can be made more uniform.

<Each configuration of the present invention will be described below>
As the outer shape of the electrostatic chuck, ceramic heater (ceramic substrate), and metal base, a circular shape can be adopted in plan view.

  -As a heat generating body, the structure by which a linear heat generating pattern is arrange | positioned over the whole surface of a center part and an outer peripheral part by planar view is employable. For example, a pattern in which the heat generation pattern is arranged in an annular shape, a U shape, or a meandering shape can be employed.

-Although it does not specifically limit as a conductor material which comprises a heat generating body (the partial heat generating body) and the electrode for adsorption | suction, For example, the following material can be used.
For example, when the ceramic substrate is made of a so-called high-temperature fired ceramic (for example, alumina), the metal powder in the conductor may be nickel (Ni), tungsten (W), molybdenum (Mo), manganese (Mn), or the like. An alloy can be selected. When the ceramic substrate is made of a so-called low-temperature fired ceramic (for example, glass ceramic), copper (Cu), silver (Ag), or an alloy thereof can be selected as the metal powder in the conductor. When the ceramic substrate is made of a high dielectric constant ceramic (for example, barium titanate), nickel (Ni), copper (Cu), silver (Ag), palladium (Pd), platinum (Pt), etc. An alloy can be selected.

Each heating element and adsorption electrode are formed by applying a conductive paste containing a metal powder, applying the paste by a conventionally known method, for example, a printing method, and then baking.
As the ceramic substrate, it is preferable to form a plurality of ceramic layers by laminating because various structures can be easily formed inside. The ceramic substrate used for the electrostatic chuck is an electrically insulating ceramic insulating plate.

  -The material constituting the ceramic substrate (in the case of a plurality of ceramic layers, each ceramic layer) is a high-temperature fired ceramic such as alumina, yttria (yttrium oxide), aluminum nitride, boron nitride, silicon carbide, silicon nitride, etc. Examples thereof include a sintered body having a main component. Depending on the application, a sintered body mainly composed of a low-temperature fired ceramic such as a glass ceramic obtained by adding an inorganic ceramic filler such as alumina to a borosilicate glass or a lead borosilicate glass may be selected. Alternatively, a sintered body mainly composed of a dielectric ceramic such as barium titanate, lead titanate, or strontium titanate may be selected.

  -Examples of metal-based materials include copper, aluminum, iron, and titanium. In addition, when bonding to the ceramic substrate with the adhesive layer, the material of the adhesive is preferably a material having a large force for bonding the ceramic substrate and the metal base, for example, a metal material such as indium, Resin materials such as silicone resin, acrylic resin, epoxy resin, polyimide resin, polyamideimide resin, and polyamide resin can be selected. However, since the difference between the thermal expansion coefficient of the ceramic substrate and the thermal expansion coefficient of the metal base is large, the adhesive is particularly preferably made of an elastically deformable resin material having a function as a buffer material.

-As a cooling part, the flow path of cooling etc. can employ | adopt the flow path of cyclic | annular form etc. by planar view, for example. In addition, as a fluid which flows through each cooling part, a fluorine-type inert fluid can be mentioned.
When manufacturing a ceramic heater, a method of simultaneously firing a ceramic substrate and a heating element can be employed. Further, when attaching the auxiliary resistor, depending on the temperature of each partial resistance of the heating element measured in the first step and the first step of heating the heating element by energizing between the pair of terminal portions, And a second step of connecting an auxiliary resistor in parallel between the terminal portions for dividing the partial resistance.

In addition, as a control method of the electrostatic chuck or the ceramic heater, the following configurations (a) and (b) can be adopted.
(A) In the ceramic heater, a variable resistor is connected in parallel to the partial resistor at one or a plurality of locations among the terminal portions that divide each partial resistor, and the ceramic heater is variable by controlling the resistance value of the variable resistor. Adjust the temperature of the partial resistance to which the resistor is connected.

  (B) In the ceramic heater, a fixed resistor is connected in parallel with the partial resistor at one or a plurality of locations among the terminal portions that divide each partial resistor, and the circuit to which the fixed resistor is connected is turned on / off. The temperature of the partial resistance to which the fixed resistance is connected is adjusted by controlling the on / off of the switch.

1 is a perspective view schematically showing a partially broken electrostatic chuck of Example 1. FIG. FIG. 4A is a cross-sectional view schematically showing the electrostatic chuck of Example 1 broken in the thickness direction and linearly arranging the partial heating elements, and FIG. 5B schematically showing the partial heating elements and their terminal portions. It is explanatory drawing shown. (A) is a top view which shows the heating zone and individual zone of the ceramic heater of Example 1, (b) is a top view which shows arrangement | positioning of the partial heat generating body etc. in the heating zone and an individual zone. (A) is a plan view showing the partial heating elements of the ceramic heater of Example 2 arranged in a straight line, and (b) is a plan view showing the partial heating elements of the ceramic heater of Example 3 arranged in a straight line. is there. (A) is a top view which shows the partial heating element of the ceramic heater of Example 4 arrange | positioned linearly, (b) is AA sectional drawing of (a), (c) is BB of (a). It is sectional drawing. It is explanatory drawing which arrange | positions linearly the partial heat generating body of the ceramic heater of Example 5, and its terminal part etc., and shows typically. It is explanatory drawing which arrange | positions linearly the partial heat generating body of the ceramic heater of Example 6, and its terminal part etc., and shows typically. (A) is a sectional view schematically showing an electrostatic chuck of Example 7 broken in the thickness direction and linearly arranging partial heating elements, and (b) schematically showing regions heated by each partial resistance. The top view to show, (c) is a top view which shows typically the area | region heated by auxiliary resistance. It is sectional drawing which fractures | ruptures the electrostatic chuck of Example 8 in the thickness direction, arrange | positions a partial heating element linearly, and shows typically, and the position of auxiliary resistance. (A) is a perspective view which shows the ceramic heater of Example 9, (b) is sectional drawing which fractures | ruptures a ceramic heater in the thickness direction and arrange | positions a partial heating element linearly, and is shown typically. The prior art is shown, (a) is a plan view of the ceramic heater, (b) is an explanatory diagram showing the state of the heat generation pattern of the ceramic heater.

  Below, the form (Example) for implementing this invention is demonstrated.

Here, for example, an electrostatic chuck capable of attracting and holding a semiconductor wafer is taken as an example.
a) First, the basic structure of the electrostatic chuck according to the first embodiment will be described.
As shown in FIG. 1, the electrostatic chuck 1 according to the first embodiment is an apparatus that adsorbs a semiconductor wafer 3 as a workpiece on the upper side of FIG. 1, and includes a ceramic heater 5 and a metal base (cooling plate) 7. Are laminated and joined.

  The upper surface (upper surface: adsorption surface) of the ceramic heater 5 in FIG. 1 is the first main surface A, and the lower surface is the second main surface B. Further, the upper surface of the metal base 7 is the third main surface C, and the lower surface is the fourth main surface D.

Among these, the ceramic heater 5 has a disk shape and is composed of a ceramic substrate 13 provided with an adsorption electrode 9 and a heating element 11 described later.
The metal base 7 has a disk shape larger in diameter than the ceramic heater 5 and is joined to the ceramic heater 5 coaxially. The metal base 7 is provided with a cooling portion (cooling path) 15 through which a cooling fluid is flowed in order to cool the ceramic substrate 13 (and hence the semiconductor wafer 3). As the cooling fluid, for example, a cooling liquid such as a fluorinated liquid or pure water can be used.

  The electrostatic chuck 1 is provided with a plurality of lift pin holes 17 into which lift pins (not shown) are inserted so as to penetrate the electrostatic chuck 1 in the thickness direction. The lift pin holes 17 are also used as cooling gas flow paths (cooling gas holes) supplied to the first main surface A side for cooling the semiconductor wafer 3. As the cooling gas, for example, an inert gas such as helium gas or nitrogen gas can be used.

b) Next, each component of the electrostatic chuck 1 will be described in detail.
In FIG. 2, for simplification of description, the heating elements 11 arranged in a ring shape (circular shape) in a plan view are shown in a straight line, and terminal portions connected to the heating elements 11 are shown. Although the number of 21 is simplified and expressed by 7, it is not limited thereto.

<Ceramic heater 5>
As schematically shown in FIG. 2A, the ceramic heater 5 (and hence the ceramic substrate 13) is bonded to the metal base 7 by a bonding layer 23 made of, for example, indium.

  The ceramic substrate 13 is formed by laminating a plurality of ceramic layers (not shown), and is an alumina sintered body mainly composed of alumina. The alumina sintered body is an insulator (dielectric).

  Inside the ceramic substrate 13, an adsorption electrode 9 and a heating element 11 are arranged from above in FIG. The adsorption electrode 9 is electrically connected to a known terminal (not shown) for applying a voltage. Further, the heating element 11 is connected to a terminal portion 21 (a terminal portion 21 including a main terminal portion 27 and a sub-terminal portion 29 described later in detail) via an internal conductive portion 25 including a via and an internal conductive layer (not shown). Is electrically connected.

<Metal base 7>
The metal base 7 is made of metal made of aluminum or an aluminum alloy. In addition to the lift pin hole 17, the metal base 7 is formed with a plurality of internal holes 33 that are through holes in which terminal fittings 31 and the like described later are disposed.

  That is, in the metal base 7, each terminal metal fitting 31 etc. are arrange | positioned for every main terminal part 27 and the subterminal part 29, and the metal base 7 is carried out in the thickness direction so that this each terminal metal fitting 31 etc. may be accommodated. An internal hole 33 is formed therethrough. In addition, an insulating cylinder 35 having electrical insulation is disposed in the inner hole 33 so as to surround the outer periphery of the terminal fitting 31.

<Adsorption electrode 9>
The adsorption electrode 9 is composed of, for example, an electrode having a circular planar shape. When the electrostatic chuck 1 is used, a DC high voltage is applied to the adsorption electrode 9, thereby generating an electrostatic attractive force (adsorption force) for adsorbing the semiconductor wafer 3. It is used to adsorb and fix the semiconductor wafer 3. In addition to the above, for the adsorption electrode 9, various known configurations (monopolar or bipolar electrodes, etc.) can be employed. The attracting electrode 9 is made of a conductive material such as W, for example.

<Heating element 11>
The heating element 11 is a resistance heating element made of a metal material (W or the like) that generates heat when a voltage is applied and a current flows.

  As shown in FIG. 3, the heating element 11 includes first to fourth heating zones 41, 43, 45, 47 arranged concentrically in a plan view (when viewed from the upper side of FIG. 2A). In each heating zone 49 (see FIG. 3A), the first to fourth partial heating elements 51, 53, 55, and 57 (see FIG. 3B) are arranged concentrically. Yes.

Details will be described below.
As shown in FIG. 3A, the ceramic substrate 13 has a plurality of planar views so that each region in its own plane direction (for example, on the first main surface A) can be heated (thus adjusting the temperature). A heating zone 49 is set.

  Specifically, the heating zone 49 provided in the ceramic substrate 13 includes a circular first heating zone 41 including the axial center, and an annular (circular) second heating that surrounds the outer periphery of the first heating zone 41 in a band shape. A zone 43, an annular (circular) third heating zone 45 surrounding the outer peripheral side of the second heating zone 43 in a strip shape, and an annular (circular) fourth heating zone 47 surrounding the outer peripheral side of the third heating zone 45 in a strip shape. These are arranged concentrically.

  The second heating zone 43 is divided into three individual zones 59 so as to have the same central angle (equal pitch), and the third heating zone 45 is divided into three individual zones 59 at an equal pitch. The fourth heating zone 47 is divided into six individual zones 59 at an equal pitch.

  Each individual zone 59 is a minimum unit that divides a heated area, and its shape is a curved arc-shaped area having a predetermined width. The first heating zone 41 itself is a single individual zone 59.

  As shown in FIG. 3B, the first to fourth heating zones 41 to 47 include first to fourth partial heating elements 51 to 57 each having one heating pattern as the heating elements 11. Has been placed. In addition, in FIG.3 (b), each partial heat generating body 51-57 is shown with the continuous line.

  The first to fourth partial heating elements 51 to 57 have a long (linear width of a predetermined width) heat generation pattern, and have a circular shape in plan view according to the shape of each heating zone 49 (however, one place) Is a notched shape).

<Arrangement of terminal portion 21>
As shown in FIG. 3B, the first partial heating element 51 has a pair of main terminal portions 27 (S1a) electrically connected to the first partial heating element 51 at both ends (open ends) of the circle. , S1b). The pair of main terminal portions 27 are provided close to each other (hereinafter, the same applies to the second to fourth partial heating elements 53 to 57).

The second partial heating element 53 is provided with a pair of main terminal portions 27 (S2a, S2b) that are electrically connected to the second partial heating element 53 at both ends of the circle.
The second partial heating element 53 is divided into three partial resistors 53a, 53b, and 53c equally between the main terminal portions 27 at both ends, that is, partial resistors 53a to 53c having the same resistance value (target value). The sub-terminal portions 29 (f2a and f2b) are provided at two locations so that

  Specifically, the main terminal portion 27 and the sub-terminal portion 29 are arranged so that the positions between the pair of adjacent main terminal portions 27 and the positions of the two sub-terminal portions 29 are at an equal pitch (120 °). Has been placed.

  As described above, the second partial heating element 53 is divided into a plurality of partial resistances 53 a to 53 c along the circumferential direction of the second partial heating element 53 by the plurality of sub-terminal portions 29 (third and fourth). The same applies to the partial heating elements 55 and 57).

The third partial heating element 55 is provided with a pair of main terminal portions 27 (S3a, S3b) electrically connected to the third partial heating element 55 at both ends of the circle.
Like the second partial heating element 53, the third partial heating element 55 is divided so that the space between the main terminal portions 27 at both ends is equally divided into three partial resistances 55a, 55b, 55c, that is, the same resistance value ( Sub-terminal portions 29 (f3a, f3b) are provided at two locations so as to be the partial resistances 55a to 55c having the target value.

The fourth partial heating element 57 is provided with a pair of main terminal portions 27 (S4a, S4b) electrically connected to the fourth partial heating element 57 at both ends of the circle.
In the fourth partial heating element 57, the sub-terminal portions 29 (f4a, f4a, 5f) are divided into six partial resistances 57a, 57b, 57c, 57d, 57e, and 57f so as to divide the gap between the main terminal portions 27 at both ends. f4b, f4c, f4d, f4e) are provided. Here, as a simple model, the fourth partial heating element 57 is divided so that the heat generation areas are equal and the partial resistances 57a to 57f have the same resistance value (target value).

Specifically, the main terminal portion 27 and the sub-terminal portion 29 are arranged so that the positions between the pair of adjacent main terminal portions 27 and the positions of the five sub-terminal portions 29 are at an equal pitch (60 °). Has been placed.
As described above, the second to fourth partial heating elements 53 to 57 are each provided with a plurality of partial resistances 53a to 53a along the circumferential direction of the second to fourth partial heating elements 53 to 57 by the plurality of sub-terminal portions 29, respectively. 53c, 55a to 55c, and 57a to 57f.

<Configuration of terminal unit 21>
Here, the configuration of each terminal portion 21 will be described using the fourth partial heating element 57 as an example.
As shown in FIG. 2A, each terminal portion 21 is formed on the inner conductive portion 25 inside the ceramic substrate 13 and the bottom surface of the inner hole 33 (the upper surface in FIG. 2A). A metallized layer 61 connected to the conductive portion 25, a connection metal (not shown) formed on the metallization layer 61, and a terminal metal 31 connected to the connection metal are provided.

  Among these, the lead metal fittings 63 (63a, 63g) are connected to the terminal metal fittings 31 (31a, 31g) of the pair of main terminal portions 27 (S4a, S4b). Electric power is supplied to the body 57.

  Of the terminal fittings 31 (31b, 31c, 31d, 31e, 31f) of the five sub-terminal portions 29 (f4a to f4e), the terminal fittings 31d, 31e of a predetermined pair of sub-terminal portions f4c, f4d. Are connected to lead metal fittings 63d and 63e, respectively, and an auxiliary resistor 65 described later is connected between the pair of lead metal fittings 63d and 63e. In addition, the terminal metal fitting 31 does not need to be arrange | positioned in the location where the auxiliary resistance 65 is not connected among the subterminal parts 29. FIG.

  That is, the resistance value of one partial resistance (for example, the fourth fourth partial resistance 57d from the left side in FIG. 2B) of the six partial resistances 57a to 57f constituting the fourth partial heating element 57 is the same. When larger than the other partial resistors, the auxiliary resistor 65 is connected in parallel with the fourth partial resistor 57d (that is, to the pair of sub-terminal portions f4c and f4d). The auxiliary resistor 65 is disposed on the back side of the metal base 7 (outside from the cooling unit 15 (on the fourth main surface D side)).

<Auxiliary resistor 65>
Here, the fourth partial heating element 57 will be described as an example.
As shown in FIG. 2B, the auxiliary resistor 65 has a resistance value of a predetermined partial resistance (for example, the resistance value R1 of the fourth partial resistance 57d), and the resistance values of the other partial resistances 57a to 57c, 57e, and 57f. In order to equalize the amount of heat generated in the fourth partial resistor 57d and the other partial resistors 57a to 57c, 57e, 57f when it is significantly larger than R, for example, when it has a large resistance value exceeding a predetermined error range. The fourth partial resistor 57d is connected in parallel.

  The error of the resistance value between the partial resistors in one partial heating element is, for example, within 5% of the target value. However, since there may actually be more variation than this, this embodiment 1 As a countermeasure, the auxiliary resistor 65, which is a fixed resistor, is connected in parallel to a partial resistor having a large resistance value (for example, the fourth partial resistor 57d).

  In this way, by connecting the auxiliary resistor 65 in parallel to the fourth partial resistor 57d, the current (I) flowing through the fourth partial heating element 57 is equal to the resistance value R1 of the fourth partial resistor 57d and the resistance of the auxiliary resistor 65. Since it is distributed according to the value R2, the first current (I1) flows through the fourth partial resistor 57d, and the second current (I2) flows through the auxiliary resistor 65.

  Therefore, by connecting the auxiliary resistor 65 in parallel to the fourth partial resistor 57d in this way, for example, the amount of heat generated in the fourth partial resistor 57d is reduced (compared to the case where the auxiliary resistor 65 is not connected), The amount of heat generated by the partial resistors 57a to 57c, 57e, and 57f is approximately the same.

  Here, in order to make the amount of heat generated in the fourth partial resistor 57d and the other partial resistors 57a to 57c, 57e, and 57f comparable, it is important what value the resistance value R2 of the auxiliary resistor 65 is set to. Therefore, a method for setting the resistance value R2 of the auxiliary resistor 65 will be described below.

  First, before connecting the auxiliary resistor 65, for example, the resistance value R of each of the partial resistors 57a to 57f of the fourth partial heating element 57 is measured. Specifically, the resistance value R of each partial resistance 57a to 57f is measured by a four-terminal measurement method using terminal portions (main terminal portion 27 and sub terminal portion 29) located at both ends of each partial resistance 57a to 57f. To do.

  Further, before connecting the auxiliary resistor 65, for example, a predetermined voltage (for example, 100 V) is applied between the pair of main terminal portions 27 of the fourth partial heating element 57, and the current flowing through the fourth partial heating element 57 at that time Measure (I).

Furthermore, the heat generation amount Q (that is, the target heat generation amount per unit time) in each of the partial resistors 57a to 57f can be obtained by the calculation of Q = I ² × R.
Further, if the auxiliary resistor 65 is connected and the amount of heat generated in each of the partial resistors 57a to 57f is the same, if the current flowing through the fourth partial resistor 57d is I1, the amount of heat generated Q (that is, the fourth partial resistor 57d (ie, The calorific value adjusted to the target calorific value) is Q = I1 ² × R1. Therefore, the relationship between the current I and the resistor R flowing through the partial resistors 57a to 57f and the current I1 flowing through the fourth partial resistor 57d and the resistance value R1 is I ² × R = I1 ² × R1.

  Furthermore, the current, voltage, and resistance have a relationship of I = I1 + I2 and if the voltage of the fourth partial resistor 57d is E1, the relationship of the voltage is E1 = R1 × I1 = R2 × I2. There is.

Therefore, the resistance value R2 of the auxiliary resistor 65 can be obtained by the calculation of R2 = R1 × √R / (√R1−√R).
<Others>
Although not shown, a power source circuit is connected to each of the attracting electrode 9 and the heating element 11 of the electrostatic chuck 1 to operate them, and their operations are controlled by an electronic control unit including a microcomputer. The

That is, the operation of the adsorption electrode 9 can be controlled (control of applied voltage, etc.) by the electronic control unit. Further, the operations of all the partial heating elements 51 to 57 can be independently controlled.
When the electrostatic chuck 1 is cooled, the ceramic heater 5 (and hence the semiconductor wafer 3) can be cooled by flowing a cooling fluid through the cooling unit 15.

c) Next, a method for manufacturing the electrostatic chuck 1 of Example 1 will be briefly described.
(1) As a raw material for the ceramic substrate 13, the main components of Al ₂ O ₃ : 92 wt%, MgO: 1 wt%, CaO: 1 wt%, and SiO ₂ : 6 wt% are mixed to form a ball mill. Then, after wet grinding for 50 to 80 hours, dehydrated and dried.

(2) Next, a solvent or the like is added to the powder and mixed with a ball mill to form a slurry.
(3) Next, this slurry is degassed under reduced pressure, and then poured into a flat plate shape and gradually cooled, and the solvent is diffused to form each alumina green sheet (corresponding to each ceramic layer).

Then, through each alumina green sheet, a space that becomes the lift pin hole 17 and the like, and further, a through hole that becomes a via is opened at a necessary place.
(4) Further, a tungsten powder is mixed in the raw material powder for the alumina green sheet to form a slurry to obtain a metallized ink.

  (5) Then, in order to form the adsorption electrode 9, the heating element 11, and the internal conductive layer, alumina (for the ceramic substrate 13) corresponding to each electrode and the heating element formation location is used by using the metallized ink. Each pattern is printed on the green sheet by a normal screen printing method. In order to form vias, metallized ink is filled into the through holes.

(6) Next, the alumina green sheets are aligned so that necessary spaces such as the lift pin holes 17 are formed, and thermocompression-bonded to form a laminated sheet (of the ceramic substrate 13).
(7) Next, each thermocompression-bonded laminated sheet is cut into a predetermined shape (that is, a disc shape).

(8) Next, each cut laminated sheet is fired in a reducing atmosphere in the range of 1400 to 1600 ° C. (for example, 1550 ° C.) for 5 hours (main firing) to produce each alumina sintered body. .
(9) Then, after firing, necessary processing such as processing on the first main surface A side is performed on each alumina sintered body to produce the ceramic substrate 13.

(10) Next, according to the ceramic substrate 13, a metallized layer 61 and a connection fitting are provided.
(11) Separately, the metal base 7 is manufactured. Specifically, the metal base 7 provided with the internal holes 33 and the like is formed by cutting the metal plate. An insulating cylinder 35 is disposed in the inner hole 33.

(12) Next, the metal base 7 and the ceramic substrate 13 are joined and integrated.
(13) Next, the terminal fitting 31 is connected to the fitting of the internal hole 33 corresponding to each terminal portion 21 of the metal base 7.

  (14) Next, by using the terminal fittings 31 (corresponding to the terminal portions 21) of the partial heating elements 51 to 57, the respective partial resistances of all the partial heating elements 51 to 57 are obtained by the method described above. Measure the resistance value.

  (15) If the resistance value of a specific partial resistor (for example, the fourth partial resistor) is significantly larger than the resistance value of other partial resistors (for example, exceeds the allowable range) by this measurement, the resistance value An auxiliary resistor 65 having a predetermined resistance value is connected between the terminal fittings 31 (specifically, lead fittings 63) of the terminal portion 21 at both ends of the large partial resistance. The resistance value of the auxiliary resistor 65 can be set by the method described above.

Thereby, the electrostatic chuck 1 of the first embodiment is completed.
d) Next, the effect of the first embodiment will be described.
In the electrostatic chuck 1 according to the first embodiment, in the ceramic heater 5, the heating element 11 (specifically, each of the partial heating elements 51 to 57) that is a resistance heating element connects an electrical path (that is, each of the main terminal portions 27). A plurality of partial resistances 53a to 53c, 55a to 55c, and 57a to 57f are divided by an intermediate subterminal portion 29 connected between the heating elements 11 themselves. Furthermore, a predetermined partial resistance (for example, a fourth partial resistance 57d) and an electric current are at least between the pair of terminal portions 21 of the terminal portion 21 including the main terminal portion 27 and the sub-terminal portion 29. Thus, an auxiliary resistor 65 is connected in parallel.

  Therefore, for example, even when the resistance values of the partial resistors 53a to 53c, 55a to 55c, and 57a to 57f are different, by adjusting the resistance value of the auxiliary resistor 65 arranged in parallel with the predetermined partial resistor (that is, an appropriate value) By using the auxiliary resistor 65 having a resistance value, the amount of heat generated in a predetermined partial resistance is reduced, and the amount of heat generated per unit area in each of the partial resistors 53a to 53c, 55a to 55c, and 57a to 57f is made uniform. Can do.

Thus, in the first embodiment, by using the auxiliary resistor 65, the in-plane temperature of the ceramic heater 5 can be easily made uniform.
When the auxiliary resistor 65 is energized, the auxiliary resistor 65 normally generates heat. However, in the first embodiment, the auxiliary resistor 65 is on the side opposite to the ceramic heater 5 from the cooling unit 15 (the fourth main surface D side). And the cooling unit 15 can relax (suppress) the temperature of the auxiliary resistor 65 on the temperature of the ceramic heater 5. Thereby, the in-plane temperature of the ceramic heater 5 can be made more uniform.

Next, the second embodiment will be described, but the description of the same parts as the first embodiment will be omitted.
In the second embodiment, since the shape or the like of the partial heating element is different, mainly the different points will be described.
FIG. 4A shows the partial heating element 71 in a plan view, but the partial heating element 71 is shown in a straight line (not an actual circular arrangement) in order to simplify the description. (The same applies to the other examples below).

  As shown in FIG. 4A, in the electrostatic chuck (and hence the ceramic heater) of the second embodiment, the partial heating element (for example, the outermost fourth partial heating element of the first embodiment) 71 has one heat generation. The heat generation pattern has a meandering shape for each individual zone corresponding to the partial resistance 77 between the terminal portions 73 and 75.

  Specifically, the partial heating element 71 includes a pair of main terminal portions 73 (73a, 73b) at both ends thereof, and the sub-terminal portions 75 (at five locations at regular intervals between the pair of main terminal portions 73a, 73b. 75a, 75b, 75c, 75d, 75e).

The heat generation pattern between the terminal portions 73 and 75 (that is, between the adjacent main terminal portion 73 and the sub-terminal portion 75 or between the adjacent sub-terminal portions 75) is formed to meander. Yes.
In the second embodiment, as in the first embodiment, an auxiliary resistor (not shown) is connected in parallel to the partial resistor 77 having a large resistance value (for example, between the sub-terminal portions 75c and 75d). Yes.

  The second embodiment has the same effect as the first embodiment and has an advantage that a large area can be heated more uniformly because the heat generation pattern meanders.

Next, Example 3 will be described, but the description of the same part as Example 2 will be omitted.
In the third embodiment, since the shape and the like of the partial heating element are different, different points will be mainly described.
As shown in FIG. 4B, in the electrostatic chuck (and hence the ceramic heater) of the third embodiment, the partial heating element (for example, the fourth partial heating element at the outermost periphery of the first embodiment) 81 is formed as shown in FIG. ) In the left-right direction (longitudinal direction), and five heat generation patterns 83 arranged in parallel, and the heat generation patterns 83 are electrically connected at a plurality of locations.

  Specifically, the partial heating element 81 includes a pair of main terminal portions 85 (85a, 85b) at both ends thereof, and the sub-terminal portions 87 at five locations at approximately equal intervals between the pair of main terminal portions 85a, 85b. (87a, 87b, 87c, 87d, 87e).

  The pair of main terminal portions 85 are connected to width patterns 89 (89a, 89g) extending in the vertical direction (short direction) in FIG. Similarly, a width pattern 89 (89b, 89c, 89d, 89e, 89f) is connected to each sub-terminal portion 87 in the lateral direction.

These width patterns 89 extend so as to intersect (orthogonally) all the heat generation patterns 83 and are electrically connected to all the heat generation patterns 83.
Here, since each portion of the heat generation pattern 83 divided by the width pattern 89 (that is, the heat generation portion for each individual zone) generates heat (in other words, the width pattern 89 is not intended for heat generation), the width of the width pattern 89 is The width of the heat generation pattern 83 is set larger. The thickness of the partial heating element 81 is uniform (target value). Accordingly, the resistance value of the width pattern 89 is smaller than the resistance value of the heat generation pattern 83 per unit area (in plan view).

  In the third embodiment, as in the first embodiment, among the partial resistances 91 between the terminal portions 85 and 87, the partial resistance 91 between the sub-terminal portions 87c and 87d having a large resistance value, for example, An auxiliary resistor (not shown) is connected in parallel.

  The third embodiment has the same effect as the second embodiment. Further, since the partial resistance 91 is formed by connecting a plurality of heat generation patterns 83 between the adjacent width patterns 89, the resistance value of the partial resistance 91 between the adjacent terminal portions 85 and 87 is reduced. Can do. Therefore, there is an advantage that the resistance value of the entire partial heating element 81 can be reduced as compared with the second embodiment.

  The partial heating element 81 of the third embodiment corresponds to a total heating element (Claim 5) in which a plurality of heating elements (here, the heating pattern 83) are electrically connected in parallel, and a width pattern 89 is connected. (Corresponding to claim 7).

Next, Example 4 will be described, but the description of the same parts as Example 2 will be omitted.
In the fourth embodiment, since the shape and the like of the partial heating element are different, different points will be mainly described.
As shown in FIG. 5A, in the electrostatic chuck (and hence the ceramic heater) of the fourth embodiment, the partial heating element (for example, the outermost fourth partial heating element of the first embodiment) 101 is the same as that of the second embodiment. The partial heating element has a shape arranged in parallel.

  That is, the partial heating element 101 is configured such that the A partial heating element 103 and the B partial heating element 105 meandering like the partial heating element of Example 2 are arranged in parallel and electrically connected in parallel. is there.

  The A partial heating element 103 and the B partial heating element 105 are arranged on both sides in the longitudinal direction in the same manner as the main terminal portion of the second embodiment, and a pair of A main terminal portions 107a and 107b and a pair of B main terminal portions 109a. 109b. The corresponding A main terminal portions 107a and 107b and the B main terminal portions 109a and 109b (in the vertical direction in the figure) are electrically connected by the connecting portions 111a and 111b, respectively. 113a and 113b are configured.

  Further, the A partial heating element 103 and the B partial heating element 105 are provided at five locations so as to equally divide the A partial heating element 103 and the B partial heating element 105, respectively, similarly to the sub-terminal portion of the second embodiment. A sub-terminal portions 115a, 115b, 115c, 115d, and 115e and B sub-terminal portions 117a, 117b, 117c, 117d, and 117e are provided. The corresponding A-sub terminal portions 115a to 115e (in the vertical direction in the figure) and the B sub-terminal portions 117a to 117e are electrically connected by the connecting portions 119a, 119b, 119c, 119d, and 119e, respectively. Thus, five pairs of sub-terminal portions 121a, 121b, 121c, 121d, and 121e are formed.

  Specifically, as shown in FIG. 5B, for example, in the main terminal portion 113 a, the A main terminal portion 107 a and the B main terminal portion 109 a have a via 123 formed in a layer different from the A partial heating element 103 and the internal They are electrically connected by a connecting portion 111 a made of a conductive layer 125.

  As shown in FIG. 5C, for example, in the sub-terminal portion 121a, the A sub-terminal portion 115a and the B sub-terminal portion 117a include a via 127 and an internal conductive layer formed in a layer different from the A partial heating element 103. They are electrically connected by a connecting portion 119a made of the layer 129.

  The partial heating element 101 of the fourth embodiment is a total heating element (Claim 5) in which a plurality of heating elements (here, the A partial heating element 103 and the B partial heating element 105) are electrically connected in parallel. Equivalent to.

Next, although Example 5 is demonstrated, description of the location similar to the said Example 1 is abbreviate | omitted.
Since the first embodiment is different in that a variable resistor is used instead of a fixed resistor as an auxiliary resistor, different points are mainly described.

  As shown in FIG. 6, in the electrostatic chuck (and hence the ceramic heater) of the fifth embodiment, the partial heating element (for example, the fourth outermost peripheral heating element of the first embodiment) 131 is similar to the first embodiment. Main terminals 133 (133a, 133b) connected to the power source are provided at both ends. Further, the sub-terminal portions 135 (135a, 135b, 135c, 135d, 135e) are provided at five locations so as to equally divide the main terminal portion 133.

  In particular, in the fifth embodiment, among the terminal portions 137 including the main terminal portion 133 and the sub-terminal portion 135, each partial resistor 139 (139a, 139b, 139c, 139d, 139e, 139f) and the electric power are provided between the adjacent terminal portions 137. Thus, variable resistors are connected as the auxiliary resistors 141 (141a, 141b, 141c, 141d, 141e, 141f) so as to be in parallel.

  Therefore, for example, when the resistance value of a certain partial resistance (for example, the third partial resistance 139c) is larger than the resistance values of the other partial resistances 139a, 139b, 139d to 139f, the third auxiliary resistor connected to the third partial resistance 139c. By adjusting the variable resistance of the resistor 141c, for example, a resistance value like the auxiliary resistor of the first embodiment can be obtained.

  In this case, the resistance values of the auxiliary resistors 141a, 141b, and 141d to 141f connected to the other partial resistors 139a, 139b, and 139d to 139f are not changed (that is, the electrical insulation state is maintained).

  In the fifth embodiment, the same effects as in the first embodiment are obtained, and the auxiliary resistors 141 (which are variable resistors) are connected to the respective partial resistors 139. Therefore, according to the resistance values of the respective partial resistors 139. There is an advantage that the resistance value of the auxiliary resistor 141 can be easily set.

  In addition, since the resistance value of the auxiliary resistor 141 can be freely set, the heat generation state of each partial resistor 139 can be easily adjusted. Therefore, there are advantages that the in-plane temperature can be made uniform and the temperature of the individual zone corresponding to each partial resistance 139 can be easily adjusted (for example, the temperature can be different from that of other individual zones).

  That is, the auxiliary resistor 141, which is a variable resistor, is connected in parallel with the partial resistor 139 at one or a plurality of locations among the terminal portions 137 that divide the partial resistors 139 of the ceramic heater, and the resistance value of the auxiliary resistor 141 is set. By controlling, the temperature of the partial resistor 139 to which the auxiliary resistor 141 is connected (and hence the temperature of the individual zone) can be easily adjusted.

Next, although Example 6 is demonstrated, description of the location similar to the said Example 1 is abbreviate | omitted.
In the first embodiment, an auxiliary resistor that is a fixed resistor is arranged between the terminal portions, and a switch that turns on and off a circuit that reaches the auxiliary resistance of each terminal portion is different. To do.

  As shown in FIG. 7, in the electrostatic chuck (and hence the ceramic heater) of the sixth embodiment, the partial heating element (for example, the fourth partial heating element at the outermost periphery of the first embodiment) 151 is similar to the first embodiment. Main terminals 153 (153a, 153b) connected to the power source are provided at both ends. Moreover, the subterminal part 155 (155a, 155b, 155c, 155d, 155e) is provided in five places so that the main terminal part 153 may be equally divided.

  In particular, in the sixth embodiment, among the terminal portions 157 including the main terminal portion 153 and the sub terminal portion 155, each of the partial resistors 159 (139a, 139b, 139c, 139d, 139e, 139f) and the electric power between the adjacent terminal portions 157. Thus, fixed resistors are connected as the auxiliary resistors 161 (161a, 161b, 161c, 161d, 161e, 161f) so as to be in parallel.

Note that the same value can be adopted as the resistance value of each auxiliary resistor 161.
Furthermore, in the sixth embodiment, each terminal portion 157 has a switch 163 that turns on (connects) or turns off (cuts off) the electrical connection between each partial resistor 159 and each auxiliary resistor 161 (connected thereto). (163a, 163b, 163c, 163d, 163e, 163f, 163g) are connected. That is, the switch 163 is provided in a circuit connecting each terminal portion 157 and each auxiliary resistor 161.

Note that the switch 163 can be arranged not on the ceramic heater but on the fourth main surface side of the electrostatic chuck, for example.
Therefore, by turning on / off the switch 163, the auxiliary resistor 161 can be connected in parallel only to the specific partial resistor 159.

  For example, when the resistance value of a certain partial resistor (for example, the third partial resistor 159c) is larger than the resistance values of the other partial resistors 159a, 159b, and 159d to 159f, the third auxiliary resistor 161c is connected in parallel to the third partial resistor 159c. In order to connect, the switches 163c and 163d of the sub-terminal portions 155b and 155c are turned on, and the other switches 163a, 163b and 163e to 163g are turned off. Thereby, for example, an auxiliary resistor can be connected as in the first embodiment.

  In the sixth embodiment, the same effects as those of the first embodiment can be obtained, and the auxiliary resistors 161 can be connected to the arbitrary partial resistors 159 by turning on / off the switches 163, respectively.

  That is, since the connection state of the auxiliary resistor 161 can be freely set, the heat generation state of each partial resistor 159 associated with the connection state of the auxiliary resistor 161 can be easily adjusted. Therefore, there is an advantage that the in-plane temperature can be made uniform and the temperature of the individual zone corresponding to each partial resistance 169 can be easily adjusted (for example, the temperature can be different from other individual zones).

  That is, the auxiliary resistor 161 that is a fixed resistor is connected in parallel with the partial resistor 169 at one or a plurality of locations between the terminal portions 157 that divide each partial resistor 169 of the ceramic heater, and the auxiliary resistor 161 is connected. A switch 163 for turning on and off the circuit is provided, and the temperature of the partial resistor 169 to which the auxiliary resistor 161 is connected can be adjusted by controlling on / off of the switch 163.

Next, although Example 7 is demonstrated, description of the location similar to the said Example 1 is abbreviate | omitted.
As shown in FIG. 8A, in the electrostatic chuck 171 of the seventh embodiment, a ceramic heater 173 and a metal base 175 are laminated as in the first embodiment.

  In the electrostatic chuck 171 of the seventh embodiment, the outermost partial heating element (for example, the outermost fourth partial heating element of the first embodiment) 177 has a main terminal portion and (main terminal portion) as in the first embodiment. A plurality of terminal portions 179 including sub-terminal portions that equally divide the space are provided.

  In addition, among the partial resistances 181 between the terminal portions 179, the auxiliary resistance 183 that is a fixed resistance is electrically connected in parallel to the partial resistance (for example, the partial resistance 181 a) having a larger resistance value than the other partial resistances. .

  The auxiliary resistor 183 is not provided in the ceramic substrate 173 to which the metal base 175 is bonded, but in the individual zone 193 in which the partial resistor 181a is arranged (the hatched portion in FIG. 8B), instead of the partial heating element 177. All the individual zones 195 of the outer peripheral portion (the shaded portion in FIG. 8C) are arranged in a circle in plan view.

  In the seventh embodiment, the same effect as in the first embodiment is obtained, and the auxiliary resistor 183 is arranged over all the individual zones 195 of the outer peripheral portion. Therefore, even when the auxiliary resistor 183 generates heat, the corresponding partial resistor is provided. It is difficult for the temperature of 181a to rise excessively. That is, there is an advantage that even if the auxiliary resistor 183 generates heat, the in-plane temperature can be easily made uniform.

  The auxiliary resistor 183 may be formed over a plurality of individual zones such as two or three instead of all the individual zones in the outer peripheral portion.

Next, although Example 8 will be described, description of the same parts as in Example 1 will be omitted.
As shown in FIG. 9, the electrostatic chuck 201 of the eighth embodiment is different from the first embodiment in the position where the auxiliary resistor 203 is attached.

Specifically, a concave accommodating portion 207 is provided on the fourth main surface D side of the metal base 205, and a conductive portion 211 connected to the auxiliary resistor 203 and the terminal fitting 209 is disposed therein.
In the eighth embodiment, the effects of the first embodiment are obtained, and the auxiliary resistor 203 is not exposed to the outside (the fourth main surface D side) of the metal base 205, so that it is difficult to contact the auxiliary resistor 203 during work or the like. Therefore, there is an advantage that the auxiliary resistor 203 can be prevented from being damaged or dropped.

Next, although Example 9 will be described, description of the same parts as in Example 1 will be omitted.
The ninth embodiment is not an electrostatic chuck but a ceramic heater.
As shown in FIG. 10A, the ceramic heater 221 of Example 9 has a disk shape, and as shown in FIG. 10B, the ceramic heater 221 (made of the same material as that of Example 1) Inside, a heating element 227 including a plurality of (for example, four) partial heating elements 225 arranged concentrically as in the first embodiment (in plan view) is arranged.

  In addition, each partial heating element 225 has a pair of main terminal portions 229 (229a and 229b) (at both ends of the partial heating element 225) connected to a power source and the main terminal portion 229, as in the first embodiment. For example, five sub-terminal portions 231 (231a, 231b, 231c, 231d, 231e) arranged at equal intervals are connected.

  Further, as in the first embodiment, among the partial resistances 235 between the adjacent terminal portions 233 (a general term for the main terminal portion 229 and the sub-terminal portion 231), a predetermined partial resistance 235 (having a larger resistance value than other partial resistances). For example, an auxiliary resistor 237 is electrically connected in parallel to the fourth partial resistor 235d).

Also in the ninth embodiment, similarly to the first embodiment, the in-plane temperature of the ceramic heater 221 can be easily equalized.
Of the configuration of the ninth embodiment, the configuration of the heating element, the terminal portion, the auxiliary resistor, the circuit connecting the terminal portion and the auxiliary resistor (electrical configuration for heating), and the like are described in the second embodiment. The heating element, terminal portion, auxiliary resistor (fixed resistance or variable resistor), switches, and circuit configuration for connecting the terminal portion and the auxiliary resistor may be replaced.

  For example, in the case where the circuit configuration using the variable resistor of the fifth embodiment or the circuit configuration using the switch of the sixth embodiment is adopted in the ninth embodiment, in addition to equalizing the temperature in the planar direction of the ceramic heater, The temperature of a predetermined area (individual zone) can be adjusted to a temperature different from other areas.

Needless to say, the present invention is not limited to the above-described embodiments and the like, and can be implemented in various modes without departing from the scope of the present invention.
(1) For example, in the electrostatic chucks of the above-described embodiments, the example in which the cooling unit is provided on the metal base is described. However, a metal base having no cooling unit may be used.

  (2) In the electrostatic chucks of the above embodiments, the electrostatic chuck in which the metal base is joined to the ceramic heater has been described. However, the present invention can also be applied to an electrostatic chuck in which the metal base is not joined.

In this case, the metal base, the connection layer, and the insulating cylinder can be omitted, and the dimension of the terminal fitting in the axial direction can be shortened.
(3) In addition, you may combine the structure of each Example with the structure of another Example suitably.

DESCRIPTION OF SYMBOLS 1,201 ... Electrostatic chuck 3 ... Semiconductor wafer 5, 221 ... Ceramic heater 7, 205 ... Metal base 9 ... Electrode for adsorption 11, 227 ... Heating element 13, 223 ... Ceramic substrate 15 ... Cooling part 21, 137, 157, 179, 233 ... terminal part 27, 73, 85, 113a, 113b, 133, 153, 229 ... main terminal part 29, 75, 87, 121a, 121b, 121c, 121d, 121e, 135, 155, 231 ... sub-terminal part 51, 53, 55, 57, 71, 81, 101, 131, 151, 177, 225... Partial heating element
53a, 53b, 53c, 55a, 55b, 55c, 57a, 57b, 57c, 57d, 57e, 57f, 77, 91, 139, 159, 181, 235... Partial resistance 65, 141, 161, 183, 203, 237. Auxiliary resistors 111a, 111b, 119a, 119b, 119c, 119d, 119e ... connection portion 163 ... switch 207 ... housing portion A ... first main surface B ... second main surface C ... third main surface D ... fourth main surface

Claims (11)

A ceramic substrate having a first main surface and a second main surface;
A heating element that is embedded in the ceramic substrate and heats a workpiece disposed on the first main surface;
In ceramic heaters with
The heating element is a resistance heating element that generates heat when energized between a pair of main terminal portions electrically connected to the heating element,
The heating element is divided into a plurality of partial resistances each having a resistance value by one or a plurality of sub-terminal portions connected between electrical paths connecting the pair of main terminal portions,
Further, an auxiliary resistor is electrically connected in parallel with the partial resistor between at least a pair of the terminal portions of the terminal portion including the pair of main terminal portions and the one or more sub terminal portions. Ceramic heater characterized by   The ceramic heater according to claim 1, wherein the auxiliary resistor is a fixed resistor or a variable resistor. When the heating element is viewed from the first main surface side,
The said heat generating body is cyclically | annularly arrange | positioned, and is divided into the said some partial resistance along the circumferential direction of the said heat generating body by the one or some said subterminal part. The ceramic heater described in 1. When the heating element and the auxiliary resistor are viewed from the first main surface side,
4. The area of the region where the auxiliary resistor is formed is set larger than the area of the region where the partial resistor to which the auxiliary resistor is connected is formed. The ceramic heater according to item.   The ceramic heater according to any one of claims 1 to 4, further comprising a total heating element in which the plurality of heating elements are electrically connected in parallel. The ceramic substrate is composed of a plurality of ceramic layers, and the all heating elements are formed on the same surface of the ceramic layers,
The ceramic heater according to claim 5, wherein a connection portion that electrically connects the plurality of heating elements is formed on a surface of the ceramic layer different from the surface. The ceramic substrate is composed of a plurality of ceramic layers, and the all heating elements are formed on the same surface of the ceramic layers,
The ceramic heater according to claim 5, wherein a connection portion that electrically connects the plurality of heating elements is formed on the same surface as the surface. The auxiliary resistor is a fixed resistor,
The ceramic heater according to claim 1, further comprising a switch for turning on and off the connection circuit. An electrostatic chuck comprising the ceramic heater according to any one of claims 1 to 8,
An electrostatic chuck comprising: an adsorption electrode embedded in the ceramic substrate for adsorbing the workpiece; and a metal base on a second main surface of the ceramic substrate.   The electrostatic chuck according to claim 9, wherein the metal base includes an accommodating portion that accommodates the auxiliary resistor on the side opposite to the second main surface side. The metal base has a cooling unit capable of cooling the ceramic substrate,
The electrostatic chuck according to claim 9, wherein the auxiliary resistor is provided on a side opposite to the second main surface side from the cooling unit.

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