JP2018157186A - Ceramic heater and electrostatic chuck and manufacturing method for ceramic heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic heater having high endurance, and being capable of restraining deterioration of a temperature distribution of the ceramic heater, and to provide an electrostatic chuck and a manufacturing method for the ceramic heater.SOLUTION: An opening 27 is formed in a ceramic substrate 17 from a second principal surface B to an electrical heating element 25. Before a sealant 29 is placed in the opening 27, a value of resistance of the electrical heating element 25 can thereby be adjusted by removing (i.e., trimming) a part of the electrical heating element 25 (more specifically, an adjustment part 59) from an outside of a ceramic heater 5 via the opening 27. In other words, via the opening 27, the value of resistance of the electrical heating element 25 can be adjusted accurately by irradiating the electrical heating element 25 with laser light, for example, and removing a part of the adjustment part 59.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a ceramic heater that can heat a workpiece such as a semiconductor wafer, an electrostatic chuck including the ceramic heater, and a method for manufacturing 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. As a fixing means for fixing the semiconductor wafer, an electrostatic chuck for fixing the semiconductor wafer by electrostatic attraction is used. Yes.

  In this electrostatic chuck, for example, an adsorption electrode is provided in a ceramic substrate, and an electrostatic attractive force generated when a voltage is applied to the adsorption electrode is used to attach a semiconductor wafer to the upper surface (adsorption surface) of the ceramic substrate. ). In the electrostatic chuck, for example, a metal base as a cooling substrate is bonded to the lower surface (bonding surface) of the ceramic substrate.

  Further, some electrostatic chucks have a function of adjusting (heating or cooling) the temperature of a semiconductor wafer adsorbed on an adsorption surface (see Patent Document 1). For example, there is a technique for heating a semiconductor wafer on an adsorption surface by disposing a heating element in a ceramic substrate and heating the ceramic substrate with the heating element.

The heating element described above is made of, for example, tungsten and is a resistance heating element that generates heat when energized. The ceramic substrate provided with this heating element is called a ceramic heater.
In recent years, demands for variations in resistance values of heating elements of electrostatic chucks have become strict. For example, the required range of resistance value variation is stricter, such as ± 15%, ± 10%, ± 5%, and ± 3%.

  By the way, when producing a heating element, since a heating pattern is formed by metallized printing and then fired, the resistance value of the heating element after firing is estimated from the thickness and width of the heating pattern before firing. However, since the resistance value of the heating element varies depending on the firing state, the actual resistance value may deviate from the estimated resistance value.

  As a countermeasure against this, a method of adjusting the resistance value by irradiating the exposed heating element with laser light after baking the heat generation pattern exposed on the substrate surface (that is, a method of adjusting the resistance value by trimming) ) Has been proposed (see Patent Document 2).

JP, 2006-001757, A International Publication No. 2002/043441

However, the above-described prior art is not always sufficient, and further improvement has been demanded.
Specifically, in the technology of trimming the heating element exposed on the substrate surface and adjusting the resistance value of the heating element, after trimming, another ceramic substrate for covering is attached so as to cover the heating element exposed on the substrate surface. Although it is necessary to attach, depending on the adhesive used when affixing, a problem may arise in the durability of the ceramic heater.

For example, when a ceramic heater is used in a plasma atmosphere, there is a problem that the adhesive deteriorates due to the plasma and the durability of the ceramic heater decreases.
In addition, due to the difference in thermal conductivity between the ceramic substrate and the adhesive, a thermal gradient may occur depending on the application state of the adhesive, which may deteriorate the temperature distribution of the ceramic heater.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a ceramic heater, an electrostatic chuck, and a ceramic heater manufacturing method that have high durability and can suppress deterioration of the temperature distribution of the ceramic heater. There is to do.

(1) A first aspect of the present invention relates to a ceramic heater in which a resistance heating element that generates heat when energized is disposed inside a ceramic substrate.
The ceramic substrate of this ceramic heater has an opening from one main surface to the resistance heating element. Inside the opening, the thermal conductivity is the same as that of the ceramic substrate or the thermal conductivity of the ceramic substrate. A sealing material having a high rate and made of at least one of ceramics and resin is disposed.

  Thus, in the first aspect, since the ceramic substrate has an opening extending from one main surface to the resistance heating element, before the sealing material is disposed, from the outside of the ceramic heater. The resistance value of the resistance heating element can be adjusted, for example, by removing a part of the resistance heating element through the opening (that is, by trimming).

That is, the resistance value of the resistance heating element can be accurately adjusted by irradiating the resistance heating element with, for example, laser light through the opening and removing a part of the resistance heating element.
In addition, when the above-described trimming is performed, the resistance value of the entire resistance heating element is increased, and the remaining trimmed part, for example, a part where the width of the resistance heating element is narrowed by trimming (hereinafter referred to as trimming remaining part). The resistance value increases. For this reason, during energization, the temperature of the remaining trimming portion is more likely to rise than the temperature of other portions.

  On the other hand, in the first aspect, the opening has the same thermal conductivity as that of the ceramic substrate or larger than that of the ceramic substrate, and is made of at least one of ceramic and resin. Since the material is arranged, even if the temperature of the trimming remainder of the resistance heating element rises, the heat of that part is quickly conducted to other parts by the sealing material with high thermal conductivity arranged in the opening. (Ie, heat drawn).

Therefore, the temperature difference between the opening where the sealing material is disposed and the surrounding portion is reduced. That is, even when trimming is performed, there is an effect that the temperature distribution in the planar direction of the ceramic heater is reduced (that is, the thermal uniformity is improved).
In the first aspect, the ceramic substrate provided with the heating element on the surface and the other ceramic substrate are not bonded with an adhesive so as to cover the entire heating element. Therefore, there is an advantage that the durability is high because the adhesive is not deteriorated by, for example, plasma during use of the ceramic heater (for example, during processing by plasma).

Note that the ceramics and resins that are the materials of the sealing material used in the first aspect have higher durability such as plasma resistance than the conventional adhesives used for bonding the ceramic substrates described above.

  (2) In the second aspect of the present invention, the resistance heating element may have a linear portion having a predetermined width in a plan view when the ceramic substrate is viewed from the thickness direction. It may be larger than the width of the linear portion.

  In the second aspect, when the width of the opening is larger than the width of the linear portion of the resistance heating element, the resistance value of the resistance heating element is adjusted by laser light or the like through the opening. It can be done easily.

  In particular, by exposing the whole of the linear portion of the resistance heating element in the width direction in the opening, it is possible to easily confirm which part should be deleted and how much to remove. There is an advantage that workability is high.

(3) In the third aspect of the present invention, the sealing material may be disposed so as to contact the resistance heating element and reach the opening end of the opening.
In the third aspect, when the sealing material is in contact with the resistance heating element, the heat is quickly released even when the temperature of the trimming remainder of the resistance heating element is higher than when the sealing material is not in contact. Can conduct to the surroundings.

  In addition, in the third aspect, when the sealing material is disposed so as to reach the opening end of the opening, for example, when a metal cooling substrate is disposed on the opening end side of the opening, the trimming remainder, etc. Heat can be quickly conducted to the cooling substrate side.

Thereby, even when trimming is performed, the temperature distribution in the planar direction of the ceramic heater is further reduced.
(4) A fourth aspect of the present invention is a metal heater bonded to the ceramic heater according to any one of the first to third aspects and a main surface side where the opening of the ceramic substrate is formed so as to cover the opening. And an electrostatic chuck.

  Such an electrostatic chuck has an effect that the temperature distribution in the plane direction of the ceramic heater (and hence the electrostatic chuck) is small even when the resistance heating element of the ceramic heater is trimmed.

(5) A fifth aspect of the present invention relates to a method for manufacturing a ceramic heater according to any one of the first to third aspects.
In this method for manufacturing a ceramic heater, a ceramic substrate having an opening is processed to remove a part of the resistance heating element through the opening to adjust the resistance value of the resistance heating element.

According to the fifth aspect, the resistance value of the resistance heating element can be adjusted easily and accurately.
(6) A sixth aspect of the present invention relates to a method for manufacturing a ceramic heater according to any one of the first to third aspects.

  In this method of manufacturing a ceramic heater, the resistance heating element has a plurality of parallel heating portions connected in parallel to the portion exposed at the opening, and the ceramic substrate having the opening via the opening. The resistance value of the resistance heating element is adjusted by disconnecting a part of the plurality of parallel heating portions of the resistance heating element.

According to the sixth aspect, the resistance value of the resistance heating element can be adjusted easily and accurately.
(7) In the seventh aspect of the present invention, after the resistance value is adjusted, the thermal conductivity of the opening is the same as that of the ceramic substrate or greater than that of the ceramic substrate, and at least of the ceramic and the resin. You may arrange | position the sealing material which consists of 1 type.

According to the seventh aspect, a ceramic heater having a small temperature distribution in the plane direction can be easily manufactured.
(8) In the eighth aspect of the present invention, first, in the first step (first step), a first ceramic green sheet and a second ceramic green sheet laminated on the first ceramic green sheet are provided. Make it.

In the next step (second step), a resistance heating element pattern made of a resistance heating element material is formed on the surface of the first ceramic green sheet.
In the next step (third step), a through hole serving as an opening is formed in the second ceramic green sheet in accordance with the position of the resistance heating element pattern on the first ceramic green sheet.

  In the next step (fourth step), the second ceramic green sheet is laminated on the first ceramic green sheet so that the position of the resistance heating element pattern is aligned with the position of the through hole. Form the body.

In the next step (fifth step), the laminate is fired to form a ceramic substrate having an opening.
In the eighth aspect, the ceramic substrate having the resistance heating element in the ceramic substrate and the opening from the substrate surface to the resistance heating element can be easily manufactured in the above-described steps.

<Each configuration of the present invention will be described below>
The ceramic substrate is a substrate (plate-shaped member) containing ceramic as a main component (50% by mass or more). Examples of the ceramic material include aluminum oxide (alumina), aluminum nitride, and yttrium oxide (yttria).

The ceramic substrate used for the electrostatic chuck is a ceramic insulating plate having electrical insulation.
-A main surface is the surface which makes the edge part in the thickness direction of a board | plate material (board | substrate).

  The resistance heating element is a heating element that generates heat when energized. Examples of the material of the resistance heating element include tungsten, tungsten carbide, molybdenum, molybdenum carbide, tantalum, and platinum.

-As a resistance heating element, the structure arrange | positioned in multiple numbers on the same plane along a main surface is employable.
-As an opening part, the opening part extended so that light can be irradiated to a resistance heating element from an opening end is mentioned. That is, the opening includes an opening extending in a direction perpendicular to the main surface.

-The sealing material which consists of at least 1 sort (s) of ceramics and resin has shown the sealing material which consists of ceramics, the sealing material which consists of resin, and the sealing material which consists of ceramics and resin.
Here, examples of the ceramic include the same types of materials as the ceramic substrate and various other materials. However, since the thermal conductivity of the sealing material is the same as that of the ceramic substrate or larger than the thermal conductivity of the ceramic substrate, the kind and components that satisfy the conditions are adopted.

  As this ceramic, aluminum oxide (alumina), aluminum nitride, yttrium oxide (yttria), etc. can be adopted. As the resin, polyphenylene sulfide (PPS) or the like can be adopted.

  Here, “consisting of” consisting of at least one of ceramics and resin is made of a material containing ceramics as a main component (50% by mass or more), or resin as a main component (59% by mass or more). This means that it is made of a material having a main component (50% by mass or more) of ceramic and resin.

As a method for adjusting the resistance value of the resistance heating element, a known resistance heating element trimming method can be employed.
For example, a part of the resistance heating element may be removed by laser light or the like. For example, the resistance value may be adjusted (specifically, the resistance value is increased) by cutting out a part of the resistance heating element to reduce the line width or the like, or providing a groove or the like on the surface. A part of the resistance heating element may be mechanically removed.

Alternatively, the resistance value may be adjusted by providing a plurality of parallel heat generating units connected in parallel to the resistance heat generating element and cutting any one or more of the parallel heat generating units.
The ceramic green sheet is a sheet formed of a material mainly composed of ceramics (that is, a sheet before firing).

It is a perspective view which shows the electrostatic chuck of 1st Embodiment. It is sectional drawing which fractures | ruptures the electrostatic chuck of 1st Embodiment in the thickness direction, and shows the one part. It is a top view which shows the heating area | region of a ceramic heater, and arrangement | positioning of a heat generating body. FIG. 4A is a plan view showing a heating element and its adjustment portion and an opening (excluding a sealing material) in the electrostatic chuck in an overlapping manner, and FIG. 4B is an AA view of FIG. 4A in the electrostatic chuck. It is sectional drawing which shows a cross section. It is a flowchart which shows the manufacturing process of a ceramic heater. It is explanatory drawing which shows the manufacturing method of a ceramic heater. (A) is a top view which shows the adjustment part before trimming exposed to an opening part, (b) is a top view which shows the adjustment part of trimming exposed to an opening part. (A) is explanatory drawing which shows the adjustment method of the resistance value of the ceramic heater of 2nd Embodiment, (b) is explanatory drawing which shows the adjustment method of the resistance value of the ceramic heater of the modification.

[1. First Embodiment]
Here, as the first embodiment, for example, an electrostatic chuck capable of attracting and holding a semiconductor wafer is taken as an example.

[1-1. Constitution]
First, the structure of the electrostatic chuck of the first embodiment will be described.
As shown in FIG. 1, the electrostatic chuck 1 of the first embodiment is a device that adsorbs a semiconductor wafer 3 as a workpiece on the upper side of FIG. 1, and a ceramic heater 5 and a cooling substrate 7 are laminated. And bonded by the adhesive layer 9.

  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 cooling substrate 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 17 provided with an adsorption electrode 11, a heat generating portion 13, and the like.
The cooling substrate 7 is a disk-shaped metal base having a diameter larger than that of the ceramic heater 5, and is joined to the ceramic heater 5 coaxially. The cooling substrate 7 is provided with a flow path (cooling path) 19 through which a cooling fluid (refrigerant) flows in order to cool the ceramic substrate 17 (and thus 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 21 or the like into which lift pins (not shown) are inserted so as to penetrate the electrostatic chuck 1 in the thickness direction. The lift pin holes 21 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.

In addition to the lift pin holes 21, a cooling gas hole (not shown) may be provided. As the cooling gas, for example, an inert gas such as helium gas or nitrogen gas can be used.
Next, each configuration of the electrostatic chuck 1 will be described in detail with reference to FIG.
<Ceramic heater>
As schematically shown in FIG. 2, the ceramic heater 5 (and hence the ceramic substrate 17) has a second main surface B side on the third main surface C side of the cooling substrate 7 by an adhesive layer 9 made of, for example, silicone. It is joined.

  The ceramic substrate 17 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 17, an adsorption electrode 11, a heat generating portion 13 including a plurality of heat generating elements 25, and the like are arranged from above in FIG. 2.
Further, as will be described later, openings 27 are respectively provided so as to reach the second main surface B from the respective heating elements 25, and a sealing material 29 is disposed in each of the openings 27.

  Furthermore, as will be described later, the ceramic substrate 17 is divided into a plurality of heating zones KZ (see FIG. 3) in a plan view as viewed from the thickness direction, and a heating element 25 is disposed in each heating zone KZ. ing. That is, the ceramic substrate 17 has a configuration in which a plurality of heating elements 25 are arranged in a plan view. The plurality of heating elements 25 are arranged on the same plane.

Each heating element 25 is electrically connected to the power supply terminal 31.
That is, each heating element 25 has its both ends (a pair of end portions 25a and 25b) on one side of the ceramic substrate 17 via the wiring portion 33 so that the temperature can be independently controlled. (That is, on the second main surface B side), each pair of power feeding terminals 31 is electrically connected.

  The wiring portion 33 includes a via 35 extending in the vertical direction (thickness direction) in FIG. 2, an internal wiring layer 37 extending in a plane direction perpendicular to the thickness direction, a terminal pad 39, and the like as a configuration for supplying power to the heating element 25. The power supply terminal 31 is connected to the terminal pad 39. The wiring part 33 is made of tungsten, for example.

The adsorption electrode 11 is electrically connected to a known electrode terminal (not shown) for applying a voltage.
<Cooling substrate>
The cooling substrate 7 is made of metal made of aluminum or an aluminum alloy. In the cooling substrate 7, in addition to the cooling path 19 and the lift pin hole 21, penetrating portions 41 that are through holes in which the electrode terminals and the power feeding terminals 31 are disposed are formed.

  A plurality of internal holes 43 extending from the fourth main surface D to the inside of the ceramic heater 5 are provided on the fourth main surface D side of the electrostatic chuck 1 in order to accommodate the power supply terminal 31. The through hole 41 of the cooling substrate 7 constitutes a part of the internal hole 43.

Further, an insulating cylinder 45 having electrical insulation is disposed in the internal hole 43 that accommodates the electrode terminal and the power feeding terminal 31.
<Adsorption electrode>
The adsorption electrode 11 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 11, 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, various known configurations (monopolar or bipolar electrodes, etc.) can be employed for the adsorption electrode 11. The adsorption electrode 11 is made of a conductive material such as tungsten.

[1-2. Structure of heating element]
<Arrangement of heating element>
First, the arrangement | positioning state of the planar direction of the heat generating body 25 is demonstrated.

  As shown in FIG. 3, the ceramic substrate 17 (and hence the ceramic heater 5) is provided with a plurality of heating zones KZ in plan view, and the temperature of each heating zone KZ is independently set in each heating zone KZ. The heating elements 25 are arranged one by one so that they can be adjusted. In addition, the planar shape of the heating element 25 is schematically shown.

  Further, the number of heating zones KZ is, for example, 200 in the range of 100 or more, for example, but is simplified in FIG. 3 (that is, the number of heating zones KZ is shown small). The heating element 25 is a resistance heating element made of a metal material (such as tungsten) that generates heat when a voltage is applied and a current flows.

<Configuration of heating element, opening, sealing material>
Next, the structure of the heat generating body 25, the opening part 27, and the sealing material 29 is demonstrated.
As shown in FIG. 4, in a plan view of the ceramic heater 5 as viewed from the second main surface B side, the heating element 25 includes a linear portion (that is, a heat generating portion that is a portion that generates heat) 51 having a predetermined width, It is comprised from the circular edge part (namely, terminal pad for heat generating bodies) 53 of the both ends which is a pad for supplying electric power to the part 51. FIG. The linear portion 51 includes a meandering portion 55 meandering a plurality of times on the side opposite to the end portion 53, and lead portions 57 connecting both ends of the meandering portion 55 and the end portions 53.

In particular, in the present embodiment, each lead portion 57 is provided with a rectangular adjustment portion 59 that is a linear portion that is wider than the other linear portions 51.
In FIG. 4A, an adjustment unit 59 before adjustment of the resistance value of the heating element 25 described later is displayed.

  Further, the ceramic heater 5 has an outer periphery from the adjusting portion 59 so as to include the adjusting portion 59 inside in a plan view so as to reach the heating element 25 from the second main surface B (that is, along the thickness direction). A large opening (that is, a large vertical and horizontal dimension) 27 is provided.

  And as shown in FIG.4 (b), the sealing material 29 of the shape similar to the shape inside the opening part 27 is inserted by each opening part 27 so that each opening part 27 may be sealed. Yes. For example, when the opening 27 is a rectangular column-shaped space, the sealing material 29 is also a rectangular column (however, the shape is slightly smaller than the opening 27).

  The sealing material 29 has the same thermal conductivity as a material such as ceramics (for example, a material mainly composed of alumina) constituting the ceramic substrate 17 or a thermal conductivity larger than that of the material such as ceramics. And it consists of at least 1 sort (s) of ceramics and resin. Specifically, the sealing material 29 is made of alumina or plastic, for example. Specifically, for example, as the material of the sealing material 29, a material such as ceramics having the same composition as the ceramic substrate 17 can be used.

As will be described later, in addition to the method of fitting the bulky sealing material 29 into the opening 29, the material of the sealing material 29 may be filled by thermal spraying and then solidified.
The sealing material 29 is in contact with the heating element 25 (specifically, the adjusting portion 59) whose tip (upper end in FIG. 4B) is exposed to the opening 27, and its rear end is the second main surface B. Has reached.

[1-3. Production method]
<Outline of ceramic heater manufacturing process>
First, based on FIG.5 and FIG.6, the outline of the manufacturing process of the ceramic heater 5 is demonstrated.

(First step)
First, as shown in FIG. 6A, a first ceramic green sheet 71a and a second ceramic green sheet 71b laminated on the first ceramic green sheet are produced. The first and second ceramic green sheets 71a and 71b represent separate ceramic green sheets, and may be laminated using a larger number of ceramic green sheets.

(Second step)
Next, as shown in FIG. 6B, a resistance heating element pattern 26 made of a resistance heating element material to be the heating element 25 is formed on the surface of the first ceramic green sheet 71a.

(Third step)
Next, as shown in FIG. 6C, the second ceramic green sheet 71b is adjusted to the adjustment unit 59 in detail in accordance with the position of the resistance heating element pattern 26 on the first ceramic green sheet 71a. A through hole 27a to be the opening 27 is formed in accordance with the position of the adjustment pattern 59a.

(4th process)
Next, as shown in FIG. 6D, on the first ceramic green sheet 71a, the position of the adjustment pattern 59a of the resistance heating element pattern 26 and the position of the through hole 27a are matched to each other. The laminated body 73 is formed by laminating the ceramic green sheets 71b.

(5th process)
Next, as shown in FIG. 6 (e), the laminate 73 is fired to form the ceramic substrate 17 (and hence the ceramic heater 5) having the heating elements 25 and the openings 27.

(Sixth step)
Next, as shown in FIG. 6 (f), a part of the heating element 25 (specifically, the adjusting portion 59) is applied to the ceramic substrate 17 having the opening 27 by laser light or the like through the opening 27. The resistance value of the heating element 25 is adjusted by performing removal processing.

(Seventh step)
Next, as shown in FIG. 6 (g), after adjusting the resistance value, the thermal conductivity of the opening 27 is the same as that of the ceramic substrate 17 or larger than that of the ceramic substrate 17, and A sealing material 29 made of at least one of ceramic and resin is disposed.

The ceramic heater 5 in which the resistance value of the heating element 25 is adjusted is obtained by the first to seventh steps described above.
<Detailed manufacturing process of electrostatic chuck>
Next, detailed contents (examples) of the entire manufacturing process of the electrostatic chuck 1 of the present embodiment will be described.

(1) First, as raw materials for the ceramic substrate 17, the main components of Al ₂ O ₃ : 92 wt%, MgO: 1 wt%, CaO: 1 wt%, and SiO ₂ : 6 wt% are mixed. Then, it is wet pulverized with a ball mill for 50-80 hours and then 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, the 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 serving as each ceramic layer. This alumina green sheet corresponds to the first and second ceramic green sheets 71a and 71b.

And the space (for example, through-hole 27a) used as the lift pin hole 21, the opening part 27 grade | etc., And the through hole used as each via | veer 35 are opened to a required location with respect to each alumina green sheet.
(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 11, the heating element 25, the internal wiring layer 37, the terminal pad 39, etc., the adsorption electrode 11, the heating element 25, the internal wiring layer 37, Each pattern (for example, the resistance heating element pattern 26) is printed on the alumina green sheet corresponding to the formation location of the terminal pad 39 and the like by a normal screen printing method. In order to form each via 35, the through hole is filled with metallized ink.

  (6) Next, the alumina green sheets are aligned so that necessary spaces such as the lift pin holes 21 and the openings 27 are formed, and thermocompression-bonded to form a laminated sheet (that is, a laminated body 73). .

(7) Next, the thermocompression-bonded laminated sheet (that is, laminated body 73) is cut into a predetermined shape (that is, a disk shape).
(8) Next, the cut laminate 73 is fired (main firing) in a reducing atmosphere in the range of 1400 to 1600 ° C. (for example, 1550 ° C.) for 5 hours to produce an alumina sintered body.

(9) Then, after firing, necessary processing such as processing on the first main surface A side is performed on the alumina sintered body to produce the ceramic substrate 17.
(10) Next, a terminal fitting (not shown) is brazed to the terminal pad 39 on the second main surface B of the ceramic substrate 17. The terminal fitting is electrically connected to the end 53 of the heating element 25.

(11) Next, the heating element 25 is trimmed through the opening 27 of the ceramic substrate 17 as will be described later, and the resistance value of the heating element 25 is adjusted.
The trimming may be performed after the firing, and may be performed after the cooling substrate 7 is joined. However, when trimming is performed after the cooling substrate 7 is joined, it is necessary to provide the cooling substrate 7 with a through hole that can be trimmed (that is, a through hole communicating with the opening 27).

  (12) Next, after trimming, a sealing material 29 is fitted into the opening 27 of the ceramic substrate 17. The sealing material 29 is prepared by firing a ceramic material in advance and processing the surface as appropriate so that the shape of the space of the opening 27 is obtained.

(13) Separately, the cooling substrate 7 is manufactured. Specifically, the cooling substrate 7 is formed by performing cutting or the like on the metal plate.
(14) Next, the cooling substrate 7 and the ceramic substrate 17 are joined and integrated. That is, the cooling substrate 7 and the ceramic substrate 17 are joined so that the opening 27 side of the ceramic substrate 17 is closed by the cooling substrate 7.

(15) Next, the power supply terminal 31 and the like are arranged to complete the electrostatic chuck 1.
<Method for adjusting the resistance value of the heating element>
Here, a method for adjusting the resistance value of the heating element 25 will be described in detail.

  As shown in FIG. 7A, the adjustment portion 59 of the heating element 25 is exposed in the opening portion 27 of the ceramic substrate 17. The width of the opening 27 (the width in the left-right direction in the figure) is larger than the width of the adjusting portion 59 of the heating element 25 that performs trimming.

  Therefore, as shown in FIG. 7B, for example, the adjustment unit 59 is irradiated with laser light through the opening 27 to remove a part of the adjustment unit 59, thereby reducing the resistance value of the heating element 25. adjust. For example, the resistance value of the heating element 25 is increased by processing the adjustment unit 59 to be narrow.

  Specifically, it can be understood how much the width should be narrowed by investigating in advance by experiment or the like how much the width is reduced and how much the resistance value of the heating element 25 is increased. Based on the findings, narrow the width. At the beginning, the width is made slightly thick so as not to excessively narrow the width.

  Next, at that stage, for example, the terminals of the tester are brought into contact with terminal fittings connected to the end portions 53 at both ends of the heating element 25, and the resistance value of the heating element 25 is measured. Thereafter, the width is slightly narrowed according to the measured resistance value, and the resistance value is measured again. By repeating such an operation, the resistance value can be accurately adjusted to a target value.

[1-4. effect]
Next, effects of the first embodiment will be described.
(1) In the first embodiment, the ceramic substrate 17 has an opening 27 extending from the second main surface B to the heating element 25. Therefore, before the sealing material 29 is disposed, the ceramic substrate 17 The resistance value of the heating element 25 is adjusted by removing a part of the heating element 25 (specifically, the adjusting unit 59) from the outside of the heater 5 through the opening 27 (specifically, by trimming). Can do.

That is, the resistance value of the heating element 25 can be adjusted with high accuracy by irradiating the heating element 25 with, for example, laser light through the opening 27 and removing a part of the adjustment unit 59.
When the above trimming is performed, the resistance value of the entire heating element 25 increases, and the resistance of the remaining trimmed part, that is, the part where the width of the heating element 25 is narrowed by trimming (that is, the remaining trimming part). The value rises. For this reason, during energization, the temperature of the remaining trimming portion is more likely to rise than the temperature of other portions.

  On the other hand, in the first embodiment, the opening 27 has the same thermal conductivity as that of the ceramic substrate 17 or higher than that of the ceramic substrate, and is made of at least one of ceramic and resin. Therefore, even when the temperature of the trimming remaining portion of the heating element 25 rises, the heat of the portion is quickly heated by the sealing material 29 having a high thermal conductivity disposed in the opening 27. Are conducted to other places (i.e., heat drawn).

Therefore, the temperature difference between the opening 27 where the sealing material 29 is disposed and the surrounding portion is reduced. That is, even when trimming is performed, there is an effect that the temperature distribution in the planar direction of the ceramic heater 5 is reduced (that is, the thermal uniformity is improved).
Further, in the first embodiment, the ceramic substrate provided with the heating element on the surface and the other ceramic substrate are not bonded with an adhesive so as to cover the entire heating element. For this reason, during use of the ceramic heater 5 (for example, during processing with plasma), the adhesive is not deteriorated by, for example, plasma, so that there is an advantage that durability is high.

  (2) In the first embodiment, the heating element 25 has a linear portion (for example, the adjustment portion 59) having a predetermined width in a plan view, and the width of the opening 27 is a line for trimming. It is larger than the width of the shaped part.

Therefore, the resistance value of the heating element 25 can be easily adjusted by laser light or the like through the opening 27 that is larger than the width of the linear portion of the heating element 25.
In particular, the entire widthwise direction of the linear portion of the heating element 25 (ie, the adjustment portion 59) is exposed in the opening 27. Therefore, it is possible to easily confirm which part should be deleted and how much, and there is an advantage that the workability at the time of trimming is high.

(3) In the first embodiment, the sealing material 29 is disposed so as to contact the heating element 25 and reach the opening end of the opening 27.
That is, since the sealing material 29 is in contact with the heating element 25, even when the temperature of the trimming remainder of the heating element 25 becomes high, the heat can be quickly conducted to the surroundings.

  In addition, since the sealing material 29 is disposed so as to reach the opening end of the opening 27 and the metal cooling substrate 7 is disposed on the opening end side of the opening 27, the heat of the trimming portion can be quickly increased. It can conduct to the cooling substrate 7 side.

Thereby, even when trimming is performed, the temperature distribution in the planar direction of the ceramic heater 5 is further reduced.
(4) In the first embodiment, the ceramic heater 5 (and thus the electrostatic chuck 1) having the above-described excellent performance can be easily manufactured by the first to seventh steps.

[1-5. Correspondence of wording]
The ceramic substrate 17, the heating element 25, the ceramic heater 5, the opening 27, the sealing material 29, the adjustment unit 59, the cooling substrate 7, the electrostatic chuck 1, the first ceramic green sheet 71 a, the first of the first embodiment. The ceramic green sheet 71b, the resistance heating element pattern 26, the through hole 27a, and the laminate 73 of the ceramic green sheet 71b, the resistance heating element, the ceramic heater, the opening, the sealing material, the linear portion, and the cooling according to the present invention are respectively shown. It corresponds to an example of a substrate, an electrostatic chuck, a first ceramic green sheet, a second ceramic green sheet, a resistance heating element pattern, a through hole, and a laminate.
[2. Second Embodiment]
Next, the second embodiment will be described, but the description similar to that of the first embodiment will be omitted or simplified. In addition, the same number is attached | subjected about the structure similar to 1st Embodiment.

Since the second embodiment differs from the first embodiment in the method of adjusting the resistance value of the heating element, the method of adjusting the resistance value of the heating element in the second embodiment will be described.
First, the configuration of the heating element in the second embodiment will be described.

  As shown in FIG. 8A, in the plan view of the ceramic heater 5 as viewed from the second main surface B side, the heating element 81 includes a linear portion (that is, a heating portion) 83 having a predetermined width and a linear portion 83. It is comprised from the circular edge part (namely, terminal pad for heat generating bodies) 85 of both ends. The linear portion 83 includes a meandering portion 87 meandering a plurality of times on the side opposite to the end portion 85, and lead portions 89 that connect both ends of the meandering portion 87 to the end portions 85.

  Particularly in the second embodiment, the meandering portion 87 includes the first parallel portion 91 and the second parallel portion 93 arranged in order from one end portion 85 side to the other end portion 85 side. Yes. That is, the first parallel part 91 and the second parallel part 93 are electrically connected in series.

  Among these, the first parallel portion 91 is obtained by electrically connecting the linear first parallel heat generating portion 101 and the linear second parallel heat generating portion 103 in parallel. Further, the second parallel portion 93 is obtained by electrically connecting a linear third parallel heat generating portion 105 and a linear fourth parallel heat generating portion 107 in parallel.

  The ceramic heater 5 has a first opening 109 that is rectangular in a plan view so as to reach the first parallel heat generating portion 101 of the heat generating element 81 from the second main surface B (that is, along the thickness direction). Is provided. The first opening 109 has an opening dimension (the vertical dimension in FIG. 8A) larger than the line width of the first parallel heat generating part 101 (the vertical dimension in FIG. 8A). In addition, the entire first parallel heat generating portion 101 (the entire width direction) is exposed in the first opening 109 before trimming.

  In addition, the dimension of the left-right direction of FIG. 8A of the 1st opening part 109 is set smaller than the dimension of the longitudinal direction of the 1st parallel heat generating part 101 (henceforth other 2nd-4th mentioned later). The same applies to the openings 111, 113, and 115).

  Similarly, the ceramic heater 5 is provided with a rectangular second opening 111 through which the second parallel heat generating portion 103 is exposed. The second opening 111 has an opening size larger than the line width of the second parallel heat generating portion 103, and before trimming, the second opening 111 has the entire second parallel heat generating portion 103 ( The whole in the width direction is exposed.

  Similarly, the ceramic heater 5 is provided with a rectangular third opening 113 through which the third parallel heat generating portion 105 is exposed. The third opening 113 has an opening size larger than the line width of the third parallel heat generating portion 105. Before the trimming, the third opening 113 has the entire third parallel heat generating portion 105 ( The whole in the width direction is exposed.

  Similarly, the ceramic heater 5 is provided with a rectangular fourth opening 115 through which the fourth parallel heat generating portion 107 is exposed. The fourth opening 115 has an opening size larger than the line width of the fourth parallel heating part 107, and before trimming, the fourth opening 115 has the entire fourth parallel heating part 107 ( The whole in the width direction is exposed.

  Accordingly, the resistance value of the heating element 81 is adjusted by, for example, irradiating the parallel heat generating units 101 to 107 to cut the laser beam through the openings 109 to 115 and cutting the parallel heat generating units 101 to 107. can do.

Next, a modification of the second embodiment will be described.
In the second embodiment, the openings 109 to 115 are provided for the parallel heat generating units 101 to 107, respectively. However, as shown in FIG. 8B, a plurality of parallel heat generating units are surrounded by one opening. In addition, an opening may be provided.

Specifically, the first opening 121 is provided so as to surround the first and second parallel heat generating units 101 and 103, and the second opening 123 is provided so as to surround the third and fourth parallel heat generating units 105 and 107. May be provided.
[3. Other Embodiments]
In addition, this invention is not limited to the said embodiment and experiment example at all, and it cannot be overemphasized that it can implement with a various aspect in the range which does not deviate from this invention.

(1) Examples of the number of heating elements arranged on the ceramic substrate include one or more.
(2) One or more openings may be provided for one heating element.

(3) When there are a plurality of heating elements, it is preferable to provide an opening for each heating element. However, some heating elements may not have an opening.
(4) When providing a plurality of openings according to one or a plurality of heating elements, it is preferable to arrange the sealing material in all the openings, but even if there is an opening where no sealing material is arranged. Good.

  (5) When there are a plurality of heating elements, when the respective sealing materials are arranged by providing openings, the thermal conductivity of each sealing material may be different, for example, sealing according to the trimming state You can select the type of material.

  For example, when there is a lot of trimming (that is, when the amount of removal of the heating element is large and thus the temperature of the trimming remainder is high), a sealing material having a high thermal conductivity is used, while the trimming is less ( That is, when the amount of heat generating element to be removed is small and therefore the temperature rise of the trimming remainder is small), a sealing material having a lower thermal conductivity may be used.

  (6) As the sealing material, a solid ceramic member, a resin member, a composite member made of ceramic and resin can be adopted. In this case, a sealing material corresponding to the hole shape of the opening may be prepared, and the sealing material may be pushed into the opening after trimming.

The shape of the sealing material is not limited to the quadrangular column as in the above-described embodiment, and any shape can be used as long as the shape reaches the resistance heating element from one of the ceramic substrates, such as a polygonal column or a cylinder.
Moreover, you may use together the sealing material of a solid ceramic member, a resin member, and a composite member, and the sealing material which has fluidity | liquidity like a cement, resin etc., and solidifies after sealing, for example. Thereby, even if the external shape of a ceramic member, a resin member, or a composite member is somewhat different from the shape of the opening, the sealing material can be filled in the opening without a gap.

  Or you may use the sealing material which has fluidity | liquidity like a cement, resin, etc., and solidifies after sealing, without using the sealing material of a solid ceramic member, a resin member, or a composite member. For example, using a material having fluidity, the opening may be filled by spraying or the like, and then solidified, so that the sealing material may be used.

  (7) In addition, the function which one component in each said embodiment has may be shared by a some component, or the function which a some component has may be exhibited by one component. Moreover, you may abbreviate | omit a part of structure of each said embodiment. In addition, at least a part of the configuration of each of the above embodiments may be added to or replaced with the configuration of another embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Electrostatic chuck 5 ... Ceramic heater 7 ... Cooling substrate 17 ... Ceramic substrate 25, 81 ... Heating element 26 ... Resistance heating element pattern 27, 109, 111, 113, 115, 121, 123 ... Opening 27a ... Through-hole 29 ... Sealing material 59 ... Adjusting part 63 ... Laminated body 71a ... First ceramic green sheet 71b ... Second ceramic green sheet 101, 103, 105, 107 ... Parallel heating part

Claims (8)

In a ceramic heater in which a resistance heating element that generates heat when energized is placed inside a ceramic substrate,
The ceramic substrate has an opening from one main surface to the resistance heating element,
Inside the opening, a sealing material having the same thermal conductivity as that of the ceramic substrate or larger than that of the ceramic substrate and made of at least one of ceramic and resin is disposed. ,
Ceramic heater. The resistance heating element has a linear portion having a predetermined width in a plan view of the ceramic substrate viewed from the thickness direction, and the width of the opening is larger than the width of the linear portion. is there,
The ceramic heater according to claim 1. The sealing material is arranged to contact the resistance heating element and reach the opening end of the opening,
The ceramic heater according to claim 1 or 2. The ceramic heater according to any one of claims 1 to 3, and a metal cooling substrate joined so as to cover the opening on a main surface side where the opening of the ceramic substrate is formed. With
Electrostatic chuck. It is a manufacturing method of the ceramic heater according to any one of claims 1 to 3,
The ceramic substrate having the opening has a step of adjusting a resistance value of the resistance heating element by performing a process of removing a part of the resistance heating element through the opening.
Manufacturing method of ceramic heater. It is a manufacturing method of the ceramic heater according to any one of claims 1 to 3,
The resistance heating element has a plurality of parallel heating parts connected in parallel to a portion exposed at the opening,
Adjusting the resistance value of the resistance heating element by disconnecting a part of the plurality of parallel heating parts of the resistance heating element via the opening with respect to the ceramic substrate having the opening. Have
Manufacturing method of ceramic heater. After the adjustment of the resistance value, a sealing material that has the same thermal conductivity as that of the ceramic substrate or larger than the thermal conductivity of the ceramic substrate in the opening and is made of at least one of ceramic and resin. Having a step of arranging
A method for manufacturing a ceramic heater according to claim 5 or 6. Producing a first ceramic green sheet and a second ceramic green sheet laminated on the first ceramic green sheet;
Forming a resistance heating element pattern made of a material of the resistance heating element on the surface of the first ceramic green sheet;
Forming a through hole serving as the opening in the second ceramic green sheet in accordance with the position of the resistance heating element pattern on the first ceramic green sheet;
A step of laminating the second ceramic green sheet on the first ceramic green sheet so as to match the position of the resistance heating element pattern and the position of the through-hole to form a laminate;
Firing the laminate and forming the ceramic substrate having the opening;
Having
The manufacturing method of the ceramic heater of any one of Claims 5-7.

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