JP6636698B2 - Stacked heating element - Google Patents

Description

  The present invention relates to a laminated heating element.

  2. Description of the Related Art Conventionally, for example, in a semiconductor manufacturing apparatus, a semiconductor wafer (for example, a silicon wafer) is fixed and processing such as dry etching is performed; For such purposes, an electrostatic chuck is used.

  When an electrostatic chuck is used in a dry etching apparatus of a semiconductor manufacturing apparatus, if the temperature of a semiconductor wafer fixed to the electrostatic chuck varies from place to place, the etching processing accuracy deteriorates. Therefore, in order to increase the processing accuracy of the semiconductor wafer, it is necessary to make the temperature of the semiconductor wafer uniform. Therefore, a heater is provided inside the electrostatic chuck, and the heater attempts to uniformly heat the semiconductor wafer.

  The electrostatic chuck with a built-in heater has a power supply path for supplying power to the heater from a terminal attached to one end on the back side, and the power supply path has a structure in which a plurality of conductive layers and a plurality of through vias are alternately stacked. Having. In the power supply path, the conductive layer adjacent to the heater generates a large amount of heat, and the heat generated by the conductive layer causes the temperature on the surface of the electrostatic chuck to be non-uniform. As a result, the temperature of the semiconductor wafer becomes uneven. It becomes even.

  Therefore, a method has been proposed in which the power supply path is divided into a plurality of layers near the conductive layer adjacent to the heater, and the current density in each layer is reduced to suppress heat generation (see Patent Document 1).

JP 2014-75525 A

  In the technique described in Patent Document 1, there is a case where heat generation in the power supply path cannot be sufficiently suppressed. The present invention has been made in view of the above points, and has as its object to provide a laminated heating element that can solve the above-described problems.

The laminated heating element of the present invention,
A ceramic substrate having a front surface and a back surface and supporting the object to be processed on the front surface; an electrode provided on the ceramic substrate for adsorbing the object to be processed; and a ceramic substrate provided on the ceramic substrate; A heater for heating the heater, a terminal attached to one end of the ceramic substrate on the back side, and a power supply path for supplying power to the heater from the terminal, wherein the power supply path is A plurality of conductive layers and a plurality of through vias provided in the ceramic substrate, and the plurality of through vias include a through via α, a through via β, a through via γ, and a through via δ defined below. Therefore, the number of combinations of through via α, through via β, through via γ, and through via δ satisfying the following conditions (1) and (2) is small. It is characterized in that at least one exists.

Through via α: A through via that connects the heater with a conductive layer X that is one of the conductive layers.
Through via β and through via γ: Through vias connecting conductive layer Y, which is one of the conductive layers, and conductive layer X.

Through via δ: A through via that connects the conductive layer Y or the conductive layer Z, which is one of the conductive layers, to the conductive layer Y.
Condition (1): When the ceramic substrate is viewed from the front side to the rear side, the through via δ is at a position overlapping with the through via β or in the vicinity thereof.

  Condition (2): When the ceramic substrate is viewed from the front surface side to the rear surface side, the position of the through via γ is a position between the through via α and the through via δ, or a position overlapping with the through via α. Or near it.

  In the laminated heating element of the present invention, the positional relationship between the through vias β and δ in at least one combination satisfies the condition (1). Therefore, the resistance of the portion from the through via δ to the through via β in the conductive layer Y decreases. Thereby, heat generation in the conductive layer Y can be suppressed.

  In the multilayer heating element of the present invention, a path passing through the through via β and a path passing through the through via γ are provided in parallel in the power supply path. Since the positional relationship between the through vias α, γ, and δ in at least one of the combinations satisfies the condition (2), a sufficient current flows not only in the path passing through the through via β but also in the path passing through the through via γ. As a result, the current flowing through the path passing through the through via β can be suppressed, and the heat generation of the path can be suppressed.

FIG. 2 is a side sectional view illustrating a configuration of the electrostatic chuck 1. FIG. 2 is a top view illustrating a configuration of the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 4 is an explanatory diagram showing a positional relationship when through vias α, β, γ, and δ are viewed from a thickness direction of a ceramic substrate 3. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias αI, αO, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias αI, αO, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 4 is an explanatory diagram showing a positional relationship when through vias α, β, γ, and δ are viewed from a thickness direction of a ceramic substrate 3. FIG. 4 is an explanatory diagram showing a positional relationship when through vias α, β, γ, and δ are viewed from a thickness direction of a ceramic substrate 3. FIG. 3 is a cross-sectional view illustrating a configuration near through vias α, β, γ, and δ in the electrostatic chuck 1. FIG. 9 is a cross-sectional view illustrating another form of through vias α, β, γ, and δ.

An embodiment of the present invention will be described.
<First embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of an electrostatic chuck 1 which is an embodiment of a laminated heating element will be described with reference to FIGS. The electrostatic chuck 1 includes a disc-shaped ceramic substrate 3, an adsorption electrode 4, an inner heater 5, an outer heater 7, and conductive layers X1, X2, X3, X4, Y1, Y2, Y3, and Y4 provided inside thereof. Is provided. Further, the electrostatic chuck 1 includes terminals 9, 11, 13, 15 and 17.

  The ceramic substrate 3 is a disk-shaped member formed by laminating and firing layers (green sheets) made of ceramic and organic components. The ceramic substrate 3 has a front surface 3a and a back surface 3b. The front surface 3a is a surface that adsorbs and supports a semiconductor wafer (for example, a silicon wafer) as an object to be processed. Hereinafter, the direction from the front surface 3a to the back surface 3b is referred to as a thickness direction. Further, the front surface 3a side is defined as an upper side, and the back surface 3b side is defined as a lower side. The green sheets constituting the ceramic substrate 3 are stacked in the thickness direction.

  The attraction electrode 4 is a metallized layer made of W, Mo, Pt, or the like. The suction electrode 4 is provided at a position near the surface 3a of the ceramic substrate 3 so as to be parallel to the surface 3a. The attraction electrode 4 is connected to the terminal 9 by a power supply path 19. The adsorption electrode 4 is an electrode for adsorbing an object to be processed on the surface 3a.

  The inner heater 5 is a heater for heating an object to be processed. The inner heater 5 is a metallized layer made of W, Mo, Pt, or the like, and is a spiral heater positioned below the attraction electrode 4. As shown in FIG. 2, when viewed from above (from the thickness direction of the ceramic substrate 3), the center of the inner heater 5 coincides with the center of the ceramic substrate 3, and the inner heater 5 extends to the center of the ceramic substrate 3. ing. The inner peripheral end 5a of the inner heater 5 is located on the conductive layer X1, and the outer peripheral end 5b is located on the conductive layer X2.

  The outer heater 7 is a heater for heating an object to be processed. The outer heater 7 is a metallized layer made of W, Mo, Pt, or the like, and is a spiral heater positioned on the same plane as the inner heater 5 and outside the inner heater 5. As shown in FIG. 2, when viewed from above, the center of the outer heater 7 coincides with the center of the ceramic substrate 3, and the outer heater 7 is located between the outermost periphery of the inner heater 5 and the outer peripheral end of the ceramic substrate 3. Has spread. An inner peripheral end 7a of the outer heater 7 is located on the conductive layer X3, and an outer peripheral end 7b is located on the conductive layer X4.

  Each of the conductive layers X1, X2, X3, and X4 is a metallized layer made of W, Mo, Pt, or the like adjacent to the inner heater 5 and the outer heater 7 below the heaters. Each of the conductive layers X1, X2, X3, and X4 has a shape obtained by dividing a circle into four equal parts, and is arranged as shown in FIG. 2 when viewed from above.

  The conductive layer X1 and the end 5a are connected by a through via α as shown in FIGS. The through via α is formed by filling a through hole formed in a ceramic layer constituting the ceramic substrate 3 with a metallization mainly containing W, Mo, Pt, or the like. The same applies to through vias β, γ, and δ described later.

  Similarly, the connection between the conductive layer X2 and the end 5b, the connection between the conductive layer X3 and the end 7a, and the connection between the conductive layer X4 and the end 7b are also made by the through via α. Hereinafter, in order to distinguish the through via α, the through via α connected to the conductive layer Xi may be referred to as a through via αi (i = 1 to 4).

  The conductive layers Y1, Y2, Y3, Y4 are metallized from W, Mo, Pt, etc., adjacent to the conductive layers X1, X2, X3, X4 below the conductive layers X1, X2, X3, X4, respectively. Layer. The conductive layers Y1, Y2, Y3, and Y4 have the same shape as the conductive layers X1, X2, X3, and X4, respectively, and are arranged as shown in FIG. 2 when viewed from above. Here, the conductive layer Y1 is located below the conductive layer X1, the conductive layer Y2 is located below the conductive layer X2, the conductive layer Y3 is located below the conductive layer X3, and the conductive layer Y4 is located below the conductive layer X3. It is located below the layer X4.

The conductive layer X1 and the conductive layer Y1 are connected by through vias β and γ, as shown in FIGS.
Similarly, the conductive layers X2 and Y2, the conductive layers X3 and Y3, and the conductive layers X4 and Y4 are also connected by through vias β and γ. In the following, in order to distinguish through vias β and γ, through vias β and γ connecting between conductive layer Xi and conductive layer Yi may be referred to as through vias βi and γi (i = 1 to 4). .

  The terminal 9 is a rod-shaped terminal made of a conductive material and provided at one end of the ceramic substrate 3 on the back surface 3b side. The terminal 9 is electrically connected to the suction electrode 4 by the power supply path 19 as described above. The power supply path 19 is a power supply path having a known structure including a conductive layer and a through via.

  The terminals 11, 13, 15, and 17 are rod-shaped terminals made of a conductive material and provided at one end of the ceramic substrate 3 on the back surface 3b side, and have the arrangement shown in FIG. 2 when viewed from above. Are provided around the terminal 9.

The terminal 11 is connected to the conductive layer Y1 by a through via δ, as shown in FIG. Similarly, the terminals 13, 15, and 17 are connected to the conductive layers Y2, Y3, and Y4, respectively, by through vias δ. Hereinafter, in order to distinguish through vias δ, through vias δ connected to conductive layers Yi may be referred to as through vias δi (i = 1 to 4).
In the electrostatic chuck 1 having the above configuration, regarding the inner heater 5, the terminal 11 → through via δ1 → conductive layer Y1 → through via β1, γ1 → conductive layer X1 → through via α1 → inner heater 5 → through via α2 → conductive layer X2 → A current path of through vias β2, γ2 → conductive layer Y2 → through via δ2 → terminal 13 is formed.

  Further, regarding the outer heater 7, the terminal 15 → through via δ3 → conductive layer Y3 → through via β3, γ3 → conductive layer X3 → through via α3 → outer heater 7 → through via α4 → conductive layer X4 → through via β4, γ4 → conductive layer Y4 → through via A current path of δ4 → terminal 17 is formed.

  The above-mentioned "terminal 11 → through via δ1 → conductive layer Y1 → through via β1, γ1 → conductive layer X1 → through via α1 → inner heater 5” and “inner heater 5 → through via α2 → conductive layer X2 → through via β2, γ2 → Conductive layer Y2 → through via δ2 → terminal 13 ”,“ terminal 15 → through via δ3 → conductive layer Y3 → through via β3, γ3 → conductive layer X3 → through via α3 → outer heater 7 ”, and“ outer heater 7 → through via α4 → conductive ”. “Layer X4 → through via β4, γ4 → conductive layer Y4 → through via δ4 → terminal 17” is an embodiment of a power supply path.

  When the through vias α, β, γ, and δ constituting each power supply path are viewed from the thickness direction of the ceramic substrate 3, the positional relationship between the through vias α, β, γ, and δ is as shown in FIG. FIG. 4 is a diagram in which the positions of the through vias α, β, γ, and δ are projected on a surface (for example, the surfaces of the conductive layers X1 and Y1) orthogonal to the thickness direction of the ceramic substrate 3.

The through via δ is near the through via β. Here, that the through via δ is in the vicinity of the through via β means that the distance D from the through via δ to the through via β is within 20 times the maximum diameter r _max of the through via δ in the orthogonal plane. . The distance D is the shortest distance from the outermost peripheral portion of the through via β to the outermost peripheral portion of the through via δ.

  When there are a plurality of through vias δ, at least one through via δ may be in the vicinity of the through via β, and the other through vias δ may not be in the vicinity of any through via β. When there are a plurality of through vias β, the through via δ may be in the vicinity of at least one through via β, and may not be in the vicinity of another through via β.

  Further, as shown in FIG. 4, the through via γ is a position between the through via α and the through via δ. The through via γ may be on a straight line L connecting the through via α and the through via δ, or may be at a position deviating from the straight line L.

  Therefore, when the through vias α, β, γ, and δ constituting each power supply path are viewed from the thickness direction of the ceramic substrate 3, the positional relationship between the through vias α, β, γ, and δ is as follows. ).

Condition (1): When the ceramic substrate 3 is viewed from the front surface 3a side to the back surface 3b side, the through via δ is located at a position overlapping with the through via β or in the vicinity thereof.
Condition (2): When the ceramic substrate 3 is viewed from the front surface 3a side to the back surface 3b side, the position of the through via γ is a position between the through via α and the through via δ, or a position overlapping with the through via α or in the vicinity thereof. is there.

2. Manufacturing Method of Electrostatic Chuck 1 The electrostatic chuck 1 can be manufactured by the following procedures (i) to (viii).
(i) A green sheet (ceramic layer) having a well-known composition is prepared using ceramic, sintering aid, organic binder and the like as raw materials.

(ii) Cutting the green sheet into a desired size.
(iii) In the green sheet, a through hole is formed in a portion where a through via is to be formed later.
(iv) Fill the through holes with metallization containing W, Mo, Pt or the like as a main component to form through vias.

  (v) A metallization mainly containing W, Mo, Pt or the like is applied to the green sheet using a screen printing method, and the adsorption electrode 4, the inner heater 5, the outer heater 7, the conductive layers X1, X2, X3, X4, Y1, Y2, Y3, Y4, etc. are formed.

  (vi) In the green sheet, holes for mounting the terminals 9, 11, 13, 15, 17 are formed by drilling. Further, the outer diameter of the green sheet is adjusted according to the shape of the electrostatic chuck 1.

(vii) The ceramic green sheets are laminated and pressed together to produce the ceramic substrate 3.
(viii) The obtained laminate is degreased and fired, and the terminals 9, 11, 13, 15, and 17 are attached to complete the electrostatic chuck 1.

3. Operation and Effect of Electrostatic Chuck 1 (1A) In the electrostatic chuck 1, the positional relationship between the through vias β and δ satisfies the condition (1). Therefore, the resistance of the portion from the through via δ to the through via β in the conductive layers Y1, Y2, Y3, Y4 decreases. Thus, heat generation in the conductive layers Y1, Y2, Y3, and Y4 can be suppressed.

  (1B) In the electrostatic chuck 1, in the power supply path, a path passing through the through via β and a path passing through the through via γ are provided in parallel. Since the positional relationship between the through vias α, γ, and δ satisfies the condition (2), a sufficient current flows not only in the path passing through the through via β but also in the path passing through the through via γ. As a result, the current flowing through the path passing through the through via β can be suppressed, and the heat generation of the path can be suppressed.

4. Method for Confirming Positional Relationship of Through Vias α, β, γ, δ The positional relationship of through vias α, β, γ, δ in the electrostatic chuck 1 can be confirmed as follows.

(i) First, the approximate positions of the through vias α, β, γ, and δ are specified using transmitted X-rays.
(ii) Next, the electrostatic chuck 1 is polished from the front surface 3a side. The polishing depth per time is set to a value sufficiently smaller than the axial length of the through vias α, β, γ, and δ.

(iii) Observe the periphery of the position specified in (i) on the polished surface to search for through vias α, β, γ, and δ.
Thereafter, the above (ii) and (iii) are alternately repeated to specify the detailed positional relationship of the through vias α, β, γ, and δ. In the second to eleventh embodiments described later, the positional relationship between the through vias α, β, γ, and δ can be similarly specified.
<Second embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of this embodiment is basically the same as that of the first embodiment. The following description focuses on the differences.

  As shown in FIG. 5, when the ceramic substrate 3 is viewed from the thickness direction, the through via δ is located at a position overlapping the through via β. Also in the present embodiment, the positional relationship between the through vias α, β, γ, and δ constituting each power supply path satisfies the conditions (1) and (2).

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the following effects in addition to the effects (1A) and (1B) of the first embodiment.

(2A) In the electrostatic chuck 1, when the ceramic substrate 3 is viewed from the thickness direction, the through via δ is located at a position overlapping the through via β. Therefore, the resistance of the portion from the through via δ to the through via β in the conductive layers Y1, Y2, Y3, Y4 is further reduced. Thereby, heat generation in the conductive layers Y1, Y2, Y3, and Y4 can be further suppressed.
<Third embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of the present embodiment is basically the same as that of the second embodiment. The following description focuses on the differences.

  As shown in FIG. 6, when the ceramic substrate 3 is viewed from the thickness direction, the through via γ is located at a position overlapping the through via α. Also in the present embodiment, the positional relationship between the through vias α, β, γ, and δ constituting each power supply path satisfies the conditions (1) and (2).

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the same effects as the effects (1A), (1B), and (2A) of the second embodiment.
<Fourth embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of the present embodiment is basically the same as that of the second embodiment. The following description focuses on the differences.

  As shown in FIG. 7, the electrostatic chuck 1 has a plurality of through vias γ. Regardless of which of the plurality of through vias γ is selected, the positional relationship between the selected through via γ and the through vias α, β, δ satisfies the above conditions (1) and (2).

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the following effects in addition to the effects (1A), (1B), and (2A) of the second embodiment.

(4A) The electrostatic chuck 1 includes a plurality of through vias γ that satisfy the above conditions (1) and (2). Therefore, the current flowing through the power supply path can be further dispersed, and heat generation can be further suppressed.
<Fifth embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of the present embodiment is basically the same as that of the second embodiment. The following description focuses on the differences.

  The electrostatic chuck 1 is provided with two inner heaters 5 in parallel, and as shown in FIG. 8, an end 5aI of one inner heater 5 and an end 5aO of the other inner heater 5 are respectively provided with through vias. is connected to the conductive layer X1 by α. Hereinafter, the through via α connected to the end 5aI is referred to as a through via αI, and the through via α connected to the end 5aO is referred to as a through via αO.

  When the ceramic substrate 3 is viewed from the thickness direction, the positional relationship between the through vias αI, β, γ, and δ is the same as the positional relationship between the through vias α, β, γ, and δ in the second embodiment. The positional relationship between the through vias αO, β, γ, and δ is the same as the positional relationship between the through vias α, β, γ, and δ in the second embodiment.

Therefore, the combination of the through vias αI, β, γ, and δ and the combination of the through vias αO, β, γ, and δ satisfy the conditions (1) and (2), respectively.
2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the same effects as the effects (1A), (1B), and (2A) of the second embodiment.
<Sixth embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of this embodiment is basically the same as that of the fifth embodiment. The following description focuses on the differences.

  As shown in FIG. 9, when the ceramic substrate 3 is viewed from the thickness direction, the position of the through via γ is not between the through via αI and the through via δ. That is, the combination of the through vias αI, β, γ, and δ does not satisfy the condition (2).

  On the other hand, when the ceramic substrate 3 is viewed from the thickness direction, the positional relationship between the through vias αO, β, γ, and δ is the same as the positional relationship between the through vias α, β, γ, and δ in the second embodiment. Therefore, the combination of the through vias αO, β, γ, δ satisfies the above conditions (1) and (2).

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the same effects as the effects (1A), (1B), and (2A) of the second embodiment.
<Seventh embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of the present embodiment is basically the same as that of the second embodiment. The following description focuses on the differences.

  As shown in FIG. 10, the conductive layer X1 includes a connection portion 21 connected to the through via β and a connection portion 23 connected to the through via γ, and has a region 25 having a larger thickness than the surroundings. The region 25 is continuous from the connection portion 21 to the connection portion 23 on the conductive layer X1. That is, the region 25 is a region connected to the through via β and a region having a larger thickness than the surroundings.

  The conductive layer Y1 includes a connection portion 27 connected to the through via δ and a connection portion 29 connected to the through via γ, and has a region 31 having a larger thickness than the surroundings. The region 31 is continuous from the connection portion 27 to the connection portion 29 on the conductive layer Y1. That is, the region 31 is a region that is connected to the through via δ and has a larger thickness than the surroundings.

  The shapes of the regions 25 and 31 when the ceramic substrate 3 is viewed from the thickness direction can be appropriately set, and can be, for example, a band, a circle, an ellipse, a rectangle, a trapezoid, a triangle, or the like. The conductive layers X2, X3, X4, Y1, Y2, Y3, and Y4 have the same configuration as the conductive layer X1.

  The region 25 can be formed as follows. When forming the ceramic substrate 3, a metallization corresponding to the entire region of the conductive layer X1 is applied to the upper surface of the green sheet below the conductive layer X1. Further, a metallization corresponding to the region 25 of the conductive layer X1 is applied to the lower surface of the green sheet above the conductive layer X1. By stacking the green sheet on the lower side of the conductive layer X1 and the green sheet on the upper side of the conductive layer X1, the conductive layer X1 in which the film thickness in the region 25 is larger than the surroundings is formed. Further, the region 31 can be similarly formed.

  In addition, as shown in FIG. 10, the region 25 may have the upper surface of the conductive layer X1 raised one step from the surroundings, or the lower surface of the conductive layer X1 may be raised one step from the surroundings. Alternatively, both the upper surface and the lower surface of the conductive layer X1 may be one level higher than the surroundings. The same applies to the area 31.

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the following effects in addition to the effects (1A), (1B), and (2A) of the second embodiment.

  (7A) The conductive layer X1 is a region that is connected to the through via β and has a region 25 that is thicker than the surroundings. Therefore, heat generation due to the current introduced into conductive layer X1 from through via β can be further suppressed.

  The conductive layer Y1 has a region 31 that is connected to the through via δ and has a larger thickness than the surroundings. Therefore, heat generation due to the current introduced into conductive layer Y1 from through via δ can be further suppressed.

(7B) The region 25 is continuous up to the connection portion 23 with the through via γ. Therefore, the effect of suppressing the heat generation of the conductive layer X1 is even more remarkable. The region 31 is continuous up to the connection portion 29 with the through via γ. Therefore, the effect of suppressing the heat generation of the conductive layer Y1 is more remarkable.
<Eighth embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of this embodiment is basically the same as that of the seventh embodiment. The following description focuses on the differences.

  As shown in FIG. 11, the region 25 in the conductive layer X1 includes the connection portion 21 with the through via β, but does not reach the through via γ. The region 31 in the conductive layer Y1 includes the connection portion 27 with the through via δ, but does not reach the through via γ. The conductive layers X2, X3, X4, Y1, Y2, Y3, and Y4 have the same configuration as the conductive layer X1.

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the same effects as the effects (1A), (1B), (2A), and (7A) of the seventh embodiment.
<Ninth embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of this embodiment is basically the same as that of the first embodiment. The following description focuses on the differences.

  As shown in FIG. 12, there are a plurality of through vias α connecting end 5a and conductive layer X1. In addition, there are a plurality of through vias β and γ that connect the conductive layer X1 and the conductive layer Y1. There are also a plurality of through vias δ connecting the conductive layer Y1 and the terminals 11.

When the through vias α, β, γ, and δ are viewed from the thickness direction of the ceramic substrate 3, the positional relationship between the through vias α, β, γ, and δ is as shown in FIG.
At least one of the plurality of through vias δ is near some or all of the through vias β. Therefore, the through vias β and δ satisfy the condition (1). At least one set of through vias α, γ, δ selected from the plurality of through vias α, γ, δ satisfies the condition (2).

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the following effects in addition to the effects (1A) and (1B) of the first embodiment.

(9A) Since the electrostatic chuck 1 has a plurality of through vias α, β, γ, and δ, the current paths are further dispersed, and heat generation in the conductive layers X1 and Y1 can be further suppressed.
<Tenth embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of this embodiment is basically the same as that of the first embodiment. The following description focuses on the differences.

  When the through vias α, β, γ, and δ are viewed from the thickness direction of the ceramic substrate 3, the positional relationship between the through vias α, β, γ, and δ is as shown in FIG. FIG. 14 is a diagram in which the positions of the through vias α, β, γ, and δ are projected on a surface (for example, the surfaces of the conductive layers X1 and Y1) orthogonal to the thickness direction of the ceramic substrate 3.

  In FIG. 14, the through via γ is not on the straight line L passing through the through via α and the through via δ, but the position of the through via γ in the direction of the straight line L is a position between the through via α and the through via δ.

The length L _{1 of the} path from the through via α to the through via δ via the through via γ (the length L1a of the line connecting the through via α and the through via γ, and the length of the line connecting the through via γ and the through via δ) is the sum of the L1b) is within 1.3 times the length L ₂ of the straight path leading to the through via δ directly through vias alpha. The length _{L 1} is preferably within 1.2 times the length _{L 2,} and still more preferably within 1.1 times. The positional relationship between the through vias β and δ is the same as in the first embodiment.

Therefore, when the through vias α, β, γ, and δ are viewed from the thickness direction of the ceramic substrate 3, the positional relationship between the through vias α, β, γ, and δ satisfies the above conditions (1) and (2).
2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the same effects as the effects (1A) and (1B) of the first embodiment.
<Eleventh embodiment>
1. Configuration of Electrostatic Chuck 1 The configuration of the electrostatic chuck 1 of this embodiment is basically the same as that of the first embodiment. The following description focuses on the differences.

  As shown in FIG. 15, the through hole δ connects the conductive layer Y1 and the conductive layer Z1 adjacent to the conductive layer Y1 on the terminal 11 side. Similarly, in conductive layers Y2, Y3, and Y4, through hole δ is connected to conductive layers Z2, Z3, and Z4.

2. Operation and Effect of Electrostatic Chuck 1 The electrostatic chuck 1 of the present embodiment has the same effects as the effects (1A) and (1B) of the first embodiment.

It should be noted that the present invention is not limited to the above-described embodiment at all, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.
(1) In the first to eleventh embodiments, the conductive layers X1, X2, X3, and X4 need not be the conductive layers adjacent to the inner heater 5 and the outer heater 7. For example, between the conductive layers X1, X2, X3, and X4 and the inner heater 5 and the outer heater 7, another conductive layer or a conductive pad (described later) forming the through via α may exist.

  In the first to eleventh embodiments, the conductive layers Y1, Y2, Y3, and Y4 need not be the conductive layers adjacent to the conductive layers X1, X2, X3, and X4. For example, between the conductive layers Y1, Y2, Y3, Y4 and the conductive layers X1, X2, X3, X4, another conductive layer or a conductive pad forming the through vias β, γ may exist.

  In the first to tenth embodiments, the conductive layers Y1, Y2, Y3, and Y4 do not have to be the conductive layers adjacent to the terminals 11, 13, 15, and 17. For example, between the conductive layers Y1, Y2, Y3, and Y4 and the terminals 11, 13, 15, and 17, there may be another conductive layer or a conductive pad forming a through via δ.

  In the eleventh embodiment, the conductive layers Y1, Y2, Y3, and Y4 need not be the conductive layers adjacent to the conductive layers Z1, Z2, Z3, and Z4. For example, between the conductive layers Y1, Y2, Y3, and Y4 and the conductive layers Z1, Z2, Z3, and Z4, another conductive layer or a conductive pad that forms a through via δ may exist.

(2) In the first to eleventh embodiments, as shown in FIG. 16, the through via α may be one in which a through via α _h , a conductive pad α _m, and a through via α _X are connected in series. Good. Through via alpha _h is a through via connecting the heater and the conductive pads alpha _m. Conductive pads alpha _m is one of the conductive layers, the conductive layer X, those that can be formed in the same manner as Y. The through via α _X is a through via that connects the conductive pad α _m and the conductive layer X. The through via alpha _h and through vias alpha _X, it is misaligned in a direction perpendicular to the thickness direction.

Similarly, the through via β may be a through via β _X , a conductive pad β _m, and a through via β _Y connected in series. The through via β _X is a through via that connects the conductive layer X and the conductive pad β _m . Conductive pads beta _m is the same as the conductive layer alpha _m. Through via beta _Y is a through via connecting the conductive pads beta _m and the conductive layer Y.

Similarly, the through via γ may be a through via γ _X , a conductive pad γ _m, and a through via γ _Y connected in series. The through via γ _X is a through via connecting the conductive layer X and the conductive pad γ _m . Conductive pads gamma _m are the same as the conductive layer alpha _m. The through via γ _Y is a through via that connects the conductive pad γ _m and the conductive layer Y.

Similarly, the through vias [delta], and through vias [delta] _Y, electrically and conductive pads [delta] _m, may be obtained by connecting the through vias [delta] _Z in series. Through via [delta] _Y is a through via connecting the conductive layer Y and the conductive pad [delta] _m. Conductive pads [delta] _m is the same as the conductive layer alpha _m. Through via [delta] _Z is a through via connecting the conductive layer Z or terminal conductive pads [delta] _m.

When the through vias β and δ are as described above, “the through via δ is in the vicinity of the through via β” means that the through via β _Y and the through via δ _Y have the above-described positional relationship in the vicinity.

  (3) In the first to eleventh embodiments, when the ceramic substrate 3 is viewed from the thickness direction, the position of the through via γ may be near the through via α. Here, the meaning of “near” is the same as the vicinity of the through vias β and δ. That is, that the position of the through via γ is in the vicinity of the through via α means that the distance from the through via γ to the through via α is within 20 times the maximum diameter of the through via γ. Here, the distance from the through via γ to the through via α is the shortest distance from the outermost peripheral portion of the through via γ to the outermost peripheral portion of the through via α.

(4) Some or all of the configurations in the first to eleventh embodiments may be appropriately combined.
(5) A ceramic heater having basically the same configuration as the first to eleventh embodiments may be manufactured. This ceramic heater can be obtained by removing the suction electrode 4, the terminal 9, and the power supply path 19 from the electrostatic chuck 1 in the first to eleventh embodiments.

  (6) Instead of including the inner heater 5 and the outer heater 7, the electrostatic chuck 1 may include a single heater. Further, three or more heaters may be provided.

DESCRIPTION OF SYMBOLS 1 ... electrostatic chuck, 3 ... ceramic substrate, 3a ... front surface, 3b ... back surface, 4 ... suction electrode, 5 ... inner heater, 5a, 5aI, 5aO, 5b ... end part, 7 ... outer heater, 7a, 7b ... end , 9, 11, 13, 15, 17 ... terminal, 19 ... power supply path, 21, 23, 27, 29 ... connection part, 25, 31 ... area, L ... straight line, X1, X2, X3, X4, Y1, Y2, Y3, Y4 ... conductive layer

Claims (5)

A ceramic substrate having a front surface and a back surface, and supporting an object to be processed on the front surface,
An electrode provided on the ceramic substrate, for adsorbing the object to be processed,
A heater provided on the ceramic substrate, for heating the object to be processed,
A terminal attached to one end of the ceramic substrate on the back side,
A power supply path for supplying power to the heater from the terminal,
The power supply path is configured by combining a plurality of conductive layers and a plurality of through vias provided in the ceramic substrate,
The plurality of through vias include a through via α, a through via β, a through via γ, and a through via δ defined below,
There must be at least one combination of four or more through vias α, four or more through vias β, four or more through vias γ, and four or more through vias δ that satisfy the following conditions (1) and (2). A laminated heating element characterized by the following.
Through via α: A through via that connects the heater with a conductive layer X that is one of the conductive layers.
Through via β and through via γ: Through vias connecting conductive layer Y, which is one of the conductive layers, and conductive layer X.
Through via δ: A through via that connects the conductive layer Y or the conductive layer Z, which is one of the conductive layers, to the conductive layer Y.
Condition (1): wherein when the ceramic substrate is viewed toward the back side from the front side, wherein the four or more through vias [delta], respectively, the position or the through vias overlap with any of the four or more through-via β The distance from δ to any one of the through vias β is within a range within 20 times the maximum diameter of the through via δ .
Condition (2): When the ceramic substrate is viewed from the front side to the rear side, the positions of the four or more through vias γ are the four or more through vias α and the four or more through vias δ. It is in a position between. When the positions of the through via α, the through via γ, and the through via δ are projected on a surface orthogonal to the direction from the front surface side to the back surface side, the through via δ passes through the through via γ from the through via α. the length L ₁ of the path, the laminated heating body according to claim 1, characterized in that the said through-via α is within 1.3 times the length L ₂ of directly the through vias δ to reach the route. The conductive layer X, the a region connected with the through vias beta, laminated heating body according to claim 1 or 2, characterized in that it has a space large thickness than the surrounding. The conductive layer Y, the a region connected with the through vias [delta], the laminated heating body according to any one of claims 1 to 3, characterized in that it has a film thickness than the surrounding thicker region. When the positions of the through via β and the through via γ are projected on a surface orthogonal to the direction from the front side to the back side, the distance from the through via β to the through via γ is the four or more through vias. The distance between any two of the through vias β is longer than the distance between any two of the four or more through vias γ, and the distance between any two of the four or more through vias γ is longer than the distance between the through vias γ. 2. The laminated heating element according to claim 1.

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