Retention device

Abstract

To provide a retention device that improves temperature uniformity of a retention surface retaining an object.SOLUTION: A retention device comprises: a plate-like member 10 which comprises a retention surface and an undersurface; and a heater electrode 50 provide at the plate-like member 10 and arranged on an XY plane substantially orthogonal to a Z-axial direction. In an electrostatic chuck which retains a semiconductor wafer W on the retention surface of the plate-like member 10, the heater electrode 50 has: a first heater pattern 51 which is arranged in a first region 61 including a pad part 50 as one end part, and comprises circular arc parts 51a, 51b and 51c; a second heater pattern 52 which is arranged in a second region 62 including a pad part 50b as the other end part and different from the first region 61, and comprises circular arc parts 52a, 52b and 52c; and a third heater pattern 53 which is connected in parallel with the second heater pattern 52. The first heater pattern 51 and second heater pattern 52 are connected in series. The third heater pattern 53 is arranged in the first region 61.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a holding device for holding an object.

Background Art

[0002] In a holding device, generally, temperature uniformity on a holding surface for holding an object is required. When an object such as a semiconductor wafer is processed with non-uniform temperature, the processing speed (chemical and physical reactions) is fast at locations with high temperature and slow at locations with low temperature, so that the object cannot be processed uniformly. Therefore, heating resistors are arranged on the same plane in the holding device, and the holding surface is uniformly heated by the heating resistors (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the heating resistors provided in the holding device are formed by pattern printing a conductive paste, variations may occur in the thickness of the conductive paste (the thickness of the heating resistor) in the printing process. When such variations occur, regions where the thickness of the heating resistor becomes thinner than the designed value are formed. Then, in the regions where the thickness of the heating resistor becomes thinner than the designed value, the resistance value of the heating resistor increases, so that the amount of heat generated increases and the temperature becomes higher than other regions. As a result, the in-plane temperature on the holding surface may not become uniform, and there is a risk that the temperature uniformity on the holding surface decreases.

[0005] Therefore, the present disclosure has been made to solve the above-described problems, and an object thereof is to provide a holding device capable of improving the temperature uniformity on a holding surface for holding an object.

Means for Solving the Problems

[0006] One aspect of the present disclosure made to solve the above problems is a plate-like member including a first surface and a second surface provided in a direction opposite to the first surface in a first direction, a heating resistor provided on the plate-like member and disposed on a plane substantially orthogonal to the first direction, in a holding device for holding an object on the first surface of the plate-like member, the heating resistor is disposed in a first region including one end of the heating resistor and includes a first heater pattern having an arc portion, is disposed in a second region different from the first region including the other end of the heating resistor and includes a second heater pattern having an arc portion, has a third heater pattern connected in parallel to the second heater pattern, the first heater pattern and the second heater pattern are connected in series, and the third heater pattern is characterized by being disposed in the first region.

[0007] For example, considering the case where the thickness of the heater pattern becomes thinner than the design value in the first region where the first heater pattern is disposed, the resistance value of the first heater pattern increases, so the calorific value in the first region increases. Therefore, the first region becomes hotter than the second region, a temperature difference occurs between the first region and the second region, and the temperature uniformity on the first surface deteriorates.

[0008] Therefore, in this holding device, a third heater pattern is provided that is connected in parallel to the second heater pattern, and the third heater pattern is arranged in the first region. That is, an additional heater pattern, the third heater pattern, is provided and connected in parallel to the second heater pattern printed with the thickness as designed.

[0009] In the parallel circuit composed of this second heater pattern and the third heater pattern, the calorific value generated in the heater pattern with the higher resistance value becomes smaller. And since the third heater pattern is arranged in the first region, like the first heater pattern, the resistance value becomes larger. Therefore, the calorific value generated in the third heater pattern decreases. As a result, in the first region, while the calorific value generated by the first heater pattern increases, the calorific value generated by the third heater pattern decreases, so that there is almost no increase or decrease in the calorific value when looking at the entire region. Therefore, since there is almost no temperature difference between the first region and the second region, the temperature uniformity on the first surface can be improved.

[0010] In the holding device described above, it is preferable that the third heater pattern is arranged along the first heater pattern.

[0011] In this way, by arranging the third heater pattern arranged in the first region along the first heater pattern, the increase in the calorific value generated in the first heater pattern can be surely offset by the decrease in the calorific value generated in the third heater pattern. Thereby, the increase and decrease in the calorific value in the first region can be almost eliminated, so that the temperature difference between the first region and the second region disappears, and the temperature uniformity on the first surface can be further improved.

[0012] In the holding device described above, it is preferable that the third heater pattern is connected to the second heater pattern via a driver electrode arranged on a plane different from the plane on which the heating resistor is arranged in the first direction and extending in a second direction substantially orthogonal to the first direction.

[0013] By doing so, the wiring freedom of the third heater pattern, and thus the design freedom of the heating resistor, can be increased. As a result, it becomes easier to realize an optimal arrangement pattern of the heating resistor, so that the temperature control accuracy on the first surface is improved, and the temperature uniformity on the first surface can be further enhanced.

[0014] In the holding device described above, Each of the first heater pattern and the second heater pattern preferably includes a plurality of arc portions arranged offset in the second direction.

[0015] Thereby, the heating resistor can be configured with a substantially spiral heater pattern. As the substantially spiral heater pattern, for example, a case where the arc portions of the first heater pattern and the arc portions of the second heater pattern are alternately connected to form a spiral pattern, or a case where each of the first heater pattern and the second heater pattern is continuously formed in a folded-back pattern and the first heater pattern and the second heater pattern are connected at one location to form a spiral pattern, etc. can be mentioned.

[0016] And by configuring such a substantially spiral heater pattern, the heating resistor can be arranged in a well-balanced manner within the plane, and the temperature uniformity on the first surface can be improved.

[0017] In the holding device described above, It is preferable that a plurality of heating zones where the heating resistor is arranged are provided.

[0018] By providing such a plurality of heating zones, temperature control can be performed with high precision on the first surface, so that the temperature uniformity on the first surface can be further improved.

[0019] In the holding device described above, The arc portions in the first heater pattern and the second heater pattern preferably have a length with a central angle of 180° to 270°.

[0020] As a result, the first heater pattern and the second heater pattern are arranged in substantially the entire circumferential region of the first surface. Therefore, on the first surface, the temperature uniformity can be improved not locally but over the entire surface (entire circumferential region).

Advantages of the Invention

[0021] According to the present disclosure, it is possible to provide a holding device capable of improving the temperature uniformity on the holding surface for holding an object.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0023] A holding device according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In the present embodiment, for example, an electrostatic chuck used in a semiconductor manufacturing apparatus such as a film forming apparatus (CVD film forming apparatus, sputtering film forming apparatus, etc.) or an etching apparatus (plasma etching apparatus, etc.) is exemplified.

[0024] [First Embodiment] First, the electrostatic chuck 1 of the first embodiment will be described with reference to FIGS. 1 to 3. The electrostatic chuck 1 of this embodiment is a device that adsorbs and holds a semiconductor wafer W (object) by electrostatic attraction, and is used, for example, to fix the semiconductor wafer W in a vacuum chamber of a semiconductor manufacturing apparatus. As shown in FIG. 1, the electrostatic chuck 1 includes a plate-like member 10, a base member 20, and a bonding layer 30 that bonds the plate-like member 10 and the base member 20.

[0025] In the following description, for convenience of explanation, the XYZ axes are defined as shown in FIG. 1. Here, the Z axis is the axis in the axial direction (vertical direction in FIG. 1) of the electrostatic chuck 1, and the X axis and the Y axis are the axes in the radial direction of the electrostatic chuck 1. Note that the Z-axis direction is an example of the "first direction" of the present disclosure, and the XY plane is an example of the "plane substantially orthogonal to the first direction" of the present disclosure.

[0026] As shown in FIG. 1, the plate-like member 10 is a disk-shaped member and is formed of ceramics. Various ceramics are used as the ceramics, but from the viewpoints of strength, wear resistance, plasma resistance, etc., for example, ceramics mainly composed of aluminum oxide (alumina, Al2O3) or aluminum nitride (AlN) are preferably used. Here, the main component means the component with the highest content ratio (for example, the component with a volume content ratio of 90 vol% or more).

[0027] Further, the diameter of the plate-like member 10 is, for example, about 150 to 300 mm. The thickness of the plate-like member 10 is, for example, about 2 to 6 mm. Note that the thermal conductivity of the plate-like member 10 is desirably in the range of 10 to 50 W / mK (more preferably 18 to 30 W / mK).

[0028] As shown in FIGS. 1 and 2, the plate-like member 10 includes a holding surface 11 that holds the semiconductor wafer W and a lower surface 12 provided on the side opposite to the holding surface 11 in the thickness direction (the direction coinciding with the Z-axis direction) of the plate-like member 10. Note that the holding surface 11 is an example of the "first surface" of the present disclosure, and the lower surface 12 is an example of the "second surface" of the present disclosure.

[0029] Inside the plate-shaped member 10, as shown in FIG. 2, a chuck electrode 40 and a heater electrode 50 are provided. The chuck electrode 40 has, for example, a substantially disk shape when viewed in the Z-axis direction, and is formed of a conductive material (for example, tungsten, molybdenum, etc.). The heater electrode 50 forms a pattern that extends, for example, in a substantially spiral shape when viewed in the Z-axis direction, and is formed of a conductive material (for example, tungsten, molybdenum, platinum, etc.). Note that the heater electrode 50 is an example of the "heating resistor" of the present disclosure, and details thereof will be described later.

[0030] Then, when power is supplied to the chuck electrode 40 from an external power source (not shown), an electrostatic attraction force (adsorption force) is generated, and the semiconductor wafer W is adsorbed and fixed to the holding surface 11 of the plate-shaped member 10 by this electrostatic attraction force. Further, when power is supplied to the heater electrode 50 from an external power source (not shown) and the heater electrode 50 generates heat, the holding surface 11 and thus the semiconductor wafer W are heated.

[0031] As shown in FIG. 1, the base member 20 includes an upper surface 21 and a lower surface 22 provided on the side opposite to the upper surface 21 in the thickness direction (i.e., the Z-axis direction) of the base member 20, and is formed in a columnar shape. This base member 20 is preferably formed of a metal (for example, aluminum or an aluminum alloy), but may be other than a metal.

[0032] The diameter of the base member 20 is, for example, about 180 mm to 350 mm. Further, the thickness (dimension in the Z-axis direction) of the base member 20 is, for example, about 20 mm to 50 mm. Note that the thermal conductivity of the base member 20 (assuming aluminum) is greater than that of the plate-shaped member 10, and is desirably in the range of 180 to 250 W / mK (preferably about 230 W / mK).

[0033] Note that a refrigerant flow path (not shown) for flowing a refrigerant (for example, a fluorine-based inert liquid or water) is formed in the base member 20. By flowing the refrigerant in this refrigerant flow path, the base member 20 is cooled, and thereby the plate-shaped member 10 is cooled via the bonding layer 30.

[0034] As shown in FIG. 1, the bonding layer 30 is disposed between the lower surface 12 of the plate-like member 10 and the upper surface 21 of the base member 20, and bonds the plate-like member 10 and the base member 20. Through this bonding layer 30, the lower surface 12 of the plate-like member 10 and the upper surface 21 of the base member 20 are thermally connected. The bonding layer 30 is composed of an adhesive such as a silicone-based resin, an acrylic-based resin, or an epoxy-based resin, and may contain a filler having thermal conductivity. Note that the thickness (dimension in the Z-axis direction) of the bonding layer 30 is, for example, about 0.1 to 1.0 mm. Also, the thermal conductivity of the bonding layer 30 is, for example, 1.0 W / mK. Note that the thermal conductivity of the bonding layer 30 (assuming a silicone-based resin) is desirably within the range of 0.1 to 2.0 W / mK (preferably 0.5 to 1.5 W / mK).

[0035] Here, the heater electrode 50 provided on the plate-like member 10 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, the heater electrode 50 is provided inside the plate-like member 10. That is, the heater electrode 50 is disposed closer to the base member 20 side than the chuck electrode 40 within the plate-like member 10.

[0036] As shown in FIG. 3, this heater electrode 50 has linear first heater patterns 51, second heater patterns 52, and third heater patterns 53. Each heater pattern 51, 52, 53 is formed of a conductive material (for example, tungsten, molybdenum, platinum, etc.). The line width of each heater pattern 51, 52, 53 is, for example, about 0.1 to 10 mm, and the thickness (dimension in the Z-axis direction) is, for example, about 0.1 to 3 mm. And as a whole, the heater electrode 50 constitutes a pattern that extends in a substantially spiral shape when viewed in the Z-axis direction.

[0037] The first heater pattern 51 is disposed in a first region 61 that includes a pad portion 50a which is one end of the heater electrode 50. Details of the first region 61 will be described later. The first heater pattern 51 includes a plurality of arc portions 51a, 51b, 51c, and the pad portion 50a of the heater electrode 50 is provided at the end of the arc portion 51c. A connection terminal 70a extending in the Z-axis direction within the plate-like member 10 is connected to the pad portion 50a (see FIG. 2). These arc portions 51a, 51b, 51c are arranged in order from the outer peripheral side toward the inner side so as to be adjacent in the radial direction. Further, the arc portions 51a, 51b include connection portions 51ac, 51bc for connecting to the arc portions 51b, 51c of the second heater pattern 52, which will be described later.

[0038] And the lengths (arc lengths) of the arc portions 51a, 51b, 51c are such that the respective central angles are about 180° to 270° (in this embodiment, about 1 / 2 to 3 / 4 of the circumference of the plate-like member 10). In this embodiment, the length of the arc portion 51a is approximately 1 / 2 of the circumference of the plate-like member 10 (the central angle of the arc portion 51a is about 180°), and since the arc portions 51b, 51c are arranged inside the arc portion 51a, the first region 61 is the region of the right half (semicircular) in the plane of the plate-like member 10 shown in FIG. 3.

[0039] The second heater pattern 52 is disposed in a second region 62 that includes a pad portion 50b which is the other end of the heater electrode 50. Details of the second region 62 will be described later. The second heater pattern 52 includes a plurality of arc portions 52a, 52b, 52c, and the pad portion 50b is provided at the end of the arc portion 52a. A connection terminal 70b extending in the Z-axis direction within the plate-like member 10 is connected to the pad portion 50b (see FIG. 2). These arc portions 52a, 52b, 52c are arranged in order from the outer peripheral side toward the inner side so as to be adjacent in the radial direction.

[0040] And the lengths (arc lengths) of the arc portions 52a, 52b, and 52c are such that the respective central angles are about 180° to 270° (in this embodiment, about 1 / 2 to 3 / 4 of the circumference of the plate-like member 10). In this embodiment, the length of the arc portion 52a is approximately 1 / 2 of the circumference of the plate-like member 10 (the central angle of the arc portion 52a is about 180°), and since the arc portions 52b and 52c are arranged inside the arc portion 52a, the second region 62 is the region of the left half (semicircular shape) in the plane of the plate-like member 10 shown in FIG. 3.

[0041] In this way, the first region 61 where the first heater pattern 51 is arranged and the second region 62 where the second heater pattern 52 is arranged occupy substantially the entire area in the plane of the plate-like member 10. Therefore, the first heater pattern 51 and the second heater pattern 52 are arranged not in a localized manner but substantially over the entire area in the plane of the plate-like member 10.

[0042] And the first heater pattern 51 and the second heater pattern 52 are connected in series. That is, the arc portions 51a, 51b, 51c of the first heater pattern 51 and the arc portions 52a, 52b, 52c of the second heater pattern 52 are connected alternately. Specifically, the arc portion 51c of the first heater pattern 51 is connected to the arc portion 52c of the second heater pattern 52. Also, the arc portion 52c of the second heater pattern 52 is connected to the arc portion 51b of the first heater pattern 51 via the connection portion 51bc. Also, the arc portion 51b of the first heater pattern 51 is connected to the arc portion 52b of the second heater pattern 52. Also, the arc portion 52b of the second heater pattern 52 is connected to the arc portion 51a of the first heater pattern 51 via the connection portion 51ac. And the arc portion 51a of the first heater pattern 51 is connected to the arc portion 52a of the second heater pattern 52. In this way, the first heater pattern 51 and the second heater pattern 52 are connected in series to form a heater pattern extending in a substantially spiral shape.

[0043] Further, the third heater pattern 53 is connected in parallel to the second heater pattern 52 and is disposed in the first region 61. Specifically, the third heater pattern 53 is connected in parallel to the arc portion 52c of the second heater pattern 52 and is disposed in the first region 61 along the arc portion 51c of the first heater pattern 51. That is, the third heater pattern 53 is disposed inside the substantially spiral heater pattern formed by the first heater pattern 51 and the second heater pattern 52. Thereby, the heater electrode 50 composed of the first, second, and third heater patterns 51, 52, and 53 can be arranged in a well-balanced manner within the plane of the plate-like member 10.

[0044] Then, the pad portions 50a and 50b of the heater electrode 50 are connected to an external power source via the connection terminals 70a and 70b, and the power supply to the first, second, and third heater patterns 51, 52, and 53 is controlled by the same power source. Thereby, the heater electrode 50 generates heat to heat the holding surface 11 and control the temperature of the holding surface 11.

[0045] Here, the heater electrode 50 is formed by pattern printing a conductive paste. However, in this printing process, variations may occur in the thickness of the conductive paste (which ultimately becomes the thickness of the heater electrode 50). Therefore, there was a possibility that a region where the thickness of the heater electrode 50 became thinner than the design value could be formed. For example, in the setting of the squeegee during printing, if there is a small inclination (an inclination at a level that cannot be controlled) and the inclination of the squeegee changes slightly each time printing is performed, due to the inclination of the squeegee, a side where the conductive paste is strongly / weakly pushed in will occur, and a difference in the thickness of the conductive paste may occur on the left and right of the squeegee (in the plane of the plate-like member 10, it can be left and right or up and down). That is, in the first region 61 and the second region 62, there is a possibility that the thickness of the heater electrode 50 is different, that is, a difference occurs between the thickness of the first heater pattern 51 and the thickness of the second heater pattern 52.

[0046] In addition, in the squeegee setting, although adjustments are made in advance considering tendencies such as certain areas being likely to be printed thickly, there may be a deviation from the assumed adjustment amount. And each time printing is performed, it is too time-consuming to measure and confirm how much deviation has occurred and then readjust accordingly before the next printing, so it is not realistically feasible. Therefore, once the squeegee is adjusted, it will be used for printing many times without changing the adjustment. As a result, in the plane of the plate-shaped member 10, in the left-right and up-down directions, that is, in the first region 61 and the second region 62, a difference in the thickness of the conductive paste will occur.

[0047] And in the region where the thickness of the heater electrode 50 is thinner than the designed value, the resistance value of the heater electrode 50 becomes larger, so the calorific value increases and it becomes hotter than other regions. Then, the in-plane temperature on the holding surface 11 does not become uniform, and the temperature uniformity on the holding surface 11 deteriorates. For example, considering the case where the thickness of the heater electrode 50 is thinner than the designed value in the first region 61, the resistance value of the first heater pattern 51 becomes larger, so the calorific value in the first region 61 increases. Therefore, the first region 61 becomes hotter than the second region 62, a temperature difference occurs between the first region 61 and the second region 62, and the temperature uniformity on the holding surface 11 deteriorates.

[0048] Therefore, in the electrostatic chuck 1 of the present embodiment, the plane of the plate-shaped member 10 is divided into a first region 61 and a second region 62. The pad portion 50a, which is the end of the heater electrode 50, and the first heater pattern 51 are arranged in the first region 61, and the pad portion 50b, which is the end of the heater electrode 50, and the second heater pattern 52 are arranged in the second region 62. And the first heater pattern 51 and the second heater pattern 52 are connected in series. In addition, a third heater pattern 53 connected in parallel to the second heater pattern 52 is provided, and the third heater pattern 53 is arranged in the first region 61.

[0049] Therefore, in the printing process, by setting a region where the thickness of the heater electrode 50 tends to be thinner than the design value as the first region 61, the third heater pattern 53 connected in parallel to the second heater pattern 52 arranged in the second region 62 printed with the thickness as designed will be provided in the first region 61 together with the first heater pattern 51.

[0050] And in the parallel circuit composed of the second heater pattern 52 and the third heater pattern 53, the calorific value generated in the heater pattern with the higher resistance value becomes smaller. Also, since the third heater pattern 53 is arranged in the first region 61, like the first heater pattern 51, its resistance value increases (the thickness becomes thinner than the design value). Therefore, the calorific value generated in the third heater pattern 53 decreases.

[0051] As a result, in the first region 61, while the calorific value generated in the first heater pattern 51 increases, the calorific value generated in the third heater pattern 53 decreases. Therefore, when viewed from the entire first region 61, there is almost no increase or decrease in the calorific value. Accordingly, since there is almost no temperature difference between the first region 61 and the second region 62, the temperature uniformity on the holding surface 11 can be improved.

[0052] Also, in the electrostatic chuck 1 of this embodiment, the third heater pattern 53 is arranged along the first heater pattern 51 (arc portion 51c). Therefore, the increase in the calorific value generated in the first heater pattern 51 can be surely offset by the decrease in the calorific value generated in the third heater pattern 53. Accordingly, the increase and decrease in the calorific value in the first region 61 can be almost eliminated, and since there is almost no temperature difference between the first region 61 and the second region 62, the temperature uniformity on the holding surface 11 can be further improved.

[0053] Further, in the electrostatic chuck 1 of the present embodiment, each of the first heater pattern 51 and the second heater pattern 52 includes a plurality of arc portions 51a, 51b, 51c and 52a, 52b, 52c that are displaced in the radial direction. Thereby, the heater electrode 50 can be configured as a substantially spiral heater pattern. Therefore, the heater electrode 50 can be arranged in the plane of the plate-like member 10 in a well-balanced manner, so that the temperature uniformity on the holding surface 11 can be improved.

[0054] And the arc portions 51a, 51b, 51c and 52a, 52b, 52c have a length of 1 / 2 to 3 / 4 of the circumference in the plate-like member 10. Thereby, the first heater pattern 51 and the second heater pattern 52 are arranged in substantially the entire area within the plane of the plate-like member 10. Therefore, the temperature uniformity can be improved over the entire surface of the holding surface 11 rather than locally.

[0055] As described above, according to the electrostatic chuck 1 of the present embodiment, in the first region 61 where the thickness of the heater electrode 50 becomes thinner than the design value, the calorific value generated by the first heater pattern 51 increases, while the calorific value generated by the third heater pattern 53 decreases. Therefore, the increase and decrease of the calorific value can be almost eliminated in the entire first region 61. Therefore, since the temperature difference can be almost eliminated between the first region 61 where the thickness of the heater electrode 50 becomes thinner than the design value and the second region 62 where the thickness of the heater electrode 50 is substantially the same as the design value, the temperature uniformity on the holding surface 11 can be improved.

[0056] [Second Embodiment] Next, the second embodiment will be described. In the second embodiment, the basic configuration is the same as that of the first embodiment, but the shapes of the first heater pattern and the second heater pattern are different from those of the first embodiment. Therefore, the same reference numerals will be given to the same configurations as those in the first embodiment, and the description will be appropriately omitted, and the description will be centered on the differences from the first embodiment.

[0057] As shown in FIG. 4, the heater electrode 150 of this embodiment forms a substantially spiral heater pattern as a whole. Specifically, the heater electrode 150 has a linear first heater pattern 151, a second heater pattern 152, and a third heater pattern 153. Each heater pattern 151, 152, 153 is formed of a conductive material (for example, tungsten, molybdenum, platinum, etc.). The line width and thickness of each heater pattern 151, 152, 153 are the same as those of the first embodiment.

[0058] The first heater pattern 151 is disposed in a first region 61 including a pad portion 150a which is one end portion of the heater electrode 150. The first heater pattern 151 includes a plurality of arc portions 151a, 151b, 151c, and the pad portion 150a of the heater electrode 150 is provided at an end of the arc portion 151b. Similar to the first embodiment, a connection terminal extending in the Z-axis direction within the plate-like member 10 is connected to the pad portion 150a. These arc portions 151a, 151b, 151c are arranged in order from the outer peripheral side toward the inner side so as to be adjacent in the radial direction. Further, the arc portions 151a, 151c include connection portions 151ac, 151bc for connecting to the arc portions 151c, 151b. Note that the lengths of the arc portions 151a, 151b, 151c are the same as those of the first embodiment, and each has a length such that the central angle is about 180° to 270°.

[0059] Thus, in the first heater pattern 151, the arc portion 151b, the connection portion 151bc, the arc portion 151c, the connection portion 151ac, and the arc portion 151a are arranged in order from the pad portion 150a. And in the first heater pattern 151, the connection portion 151bc and the connection portion 151ac serve as folded-back portions, and in the first region 61, a substantially spiral pattern is formed by one continuous heater line.

[0060] The second heater pattern 152 is disposed in a second region 62 including a pad portion 150b which is the other end of the heater electrode 150. The second heater pattern 152 includes a plurality of arc portions 152a, 152b, 152c, and the pad portion 150b of the heater electrode 150 is provided at an end of the arc portion 152b. Similar to the first embodiment, a connection terminal extending in the Z-axis direction within the plate-like member 10 is connected to the pad portion 150b. These arc portions 152a, 152b, 152c are arranged in order from the outer peripheral side toward the inner side so as to be adjacent in the radial direction. Further, the arc portions 152a, 152c include connection portions 152ac, 152bc for connecting to the arc portions 152c, 152b. Note that the lengths of the arc portions 152a, 152b, 152c are such that the respective central angles are about 180° to 270°, similar to the first embodiment.

[0061] Thus, in the second heater pattern 152, the arc portion 152b, the connection portion 152bc, the arc portion 152c, the connection portion 152ac, and the arc portion 152a are arranged in order from the pad portion 150b. And, in the second heater pattern 152, the connection portion 152bc and the connection portion 152ac serve as folded portions, and in the second region 62, a substantially spiral heater pattern is formed by a single continuous heater line.

[0062] The first heater pattern 151 and the second heater pattern 152 having such a configuration are connected in series. That is, the arc portion 151a of the first heater pattern 151 is connected to the arc portion 152a of the second heater pattern 152. Thereby, a substantially spiral heater pattern is formed in the entire heater electrode 150.

[0063] And the third heater pattern 153 is connected in parallel to the second heater pattern 152 and is disposed in the first region 61. Specifically, the third heater pattern 153 is connected in parallel to the arc portion 152c of the second heater pattern 52 and is disposed in the first region 61 along the arc portion 151c of the first heater pattern 151. That is, the third heater pattern 153 is disposed inside the heater patterns of the first heater pattern 151 and the second heater pattern 152. Thereby, the heater electrode 150 composed of the first, second, and third heater patterns 151, 152, and 153 can be arranged well-balanced within the plane of the plate-like member 10.

[0064] The pad portions 150a and 150b of the heater electrode 150 configured as such are connected to an external power source via connection terminals, and the power supply to the first, second, and third heater patterns 151, 152, and 153 is controlled by the same power source. Thereby, the heater electrode 150 generates heat, heats the holding surface 11, and the temperature control of the holding surface 11 is implemented.

[0065] By providing the heater electrode 150 having such a shape on the plate-like member 10, in the first region 61 where the thickness of the heater electrode 150 becomes thinner than the design value, similar to the first embodiment, while the calorific value generated by the first heater pattern 151 increases, the calorific value generated by the third heater pattern 153 decreases. Therefore, the increase and decrease in the calorific value can be almost eliminated when viewed from the entire first region 61. Accordingly, in the first region 61 where the thickness of the heater electrode 150 becomes thinner than the design value and the second region 62 where the thickness of the heater electrode 150 is almost the same as the design value, the temperature difference can be almost eliminated, and thus the temperature uniformity on the holding surface 11 can be improved.

[0066] [Third Embodiment] Finally, the third embodiment will be described. In the third embodiment, the basic configuration is the same as that of the first embodiment, but the holding surface 11 heated by the heater electrodes is divided into a plurality of heating zones, and heater electrodes independently controlled for each heating zone are provided, which is different from the first embodiment. Therefore, the same components as those in the first embodiment will be denoted by the same reference numerals and the description will be omitted as appropriate, and the description will focus on the differences from the first embodiment. In this embodiment, a case of a two-zone pattern in which the holding surface 11 is divided into an inner heating zone Z1 and an outer heating zone Z2 by a boundary indicated by a circular broken line in FIG. 5 and two heating zones are provided will be exemplified.

[0067] In this embodiment, as shown in FIG. 5, the plate-like member 10 includes a heater electrode 250 in addition to the heater electrode 50. That is, the heater electrode 50 is disposed in a circular inner heating zone Z1 formed in the inner region of the plate-like member 10, and the heater electrode 250 is disposed in an annular outer heating zone Z2 formed in the outer peripheral region of the plate-like member 10. These heater electrodes 50 and 250 are formed on the same surface within the plate-like member 10. As a result, on the in-plane (holding surface 11) of the plate-like member 10, there are formed two heating zones: an inner heating zone Z1 where the heater electrode 50 is disposed and which is mainly heated by the heater electrode 50, and an outer heating zone Z2 where the heater electrode 250 is disposed and which is mainly heated by the heater electrode 250.

[0068] And the power supply to the heater electrode 50 and the heater electrode 250 can be independently controlled. In this way, by providing a plurality of heating zones Z1 and Z2, the temperature control on the holding surface 11 can be performed with high precision.

[0069] Here, the heater electrode 250 disposed in the outer heating zone Z2 has a linear first heater pattern 251, a second heater pattern 252, and a third heater pattern 253. Each of the heater patterns 251, 252, 253 is formed of a conductive material (for example, tungsten, molybdenum, platinum, etc.). The line width and thickness of each of the heater patterns 251, 252, 253 are the same as those in the first embodiment.

[0070] The first heater pattern 251 is disposed in a first region 61 including a pad portion 250a which is one end portion (for example, the OUT side) of the heater electrode 250. The first heater pattern 251 is formed in an arc shape, and the pad portion 250a of the heater electrode 250 is provided at its end. That is, the first heater pattern 251 has only one arc portion. And, as shown in FIG. 6, a connection terminal 270a extending in the Z-axis direction within the plate-like member 10 is connected to the pad portion 250a. In FIG. 6, in order to clearly explain the connection structure of the heater electrode 250, the heater electrode 50 is omitted except for the pad portions 50a, 50b.

[0071] As shown in FIG. 5, the second heater pattern 252 is disposed in a second region 62 including a pad portion 250b which is the other end portion (for example, the IN side) of the heater electrode 250. The second heater pattern 252 is formed in an arc shape, and the pad portion 250b of the heater electrode 250 is provided at its end. That is, the second heater pattern 252 has only one arc portion. And, as shown in FIG. 6, a connection terminal 270b extending in the Z-axis direction within the plate-like member 10 is connected to the pad portion 250b via a via 273 and a driver electrode 255 which will be described later.

[0072] The first heater pattern 251 and the second heater pattern 252 are connected in series. Thereby, a circumferential heater pattern along the vicinity of the outer periphery of the plate-like member 10 is formed in the entire heater electrode 250.

[0073] Further, the third heater pattern 253 is connected in parallel to the second heater pattern 252 and is disposed in the first region 61. Specifically, the third heater pattern 253 is connected in parallel to the second heater pattern 252 and is disposed in the first region 61 along the first heater pattern 251. That is, the third heater pattern 153 is disposed inside the heater patterns of the first heater pattern 151 and the second heater pattern 152.

[0074] Here, since the heater electrode 50 is disposed inside the heater electrode 250, it is difficult to connect the third heater pattern 253 in parallel to the second heater pattern 252 in the same plane of the plate-like member 10 as in the first embodiment. Therefore, in the present embodiment, as shown in FIG. 6, a driver electrode 255 extending in the plane direction (XY plane direction) is provided in a plane different from the plane in which the heater electrode 250 is formed within the plate-like member 10. This driver electrode 255 has a larger cross-sectional area than the heater electrode 250 (for example, the line width is made thicker). Therefore, the driver electrode 255 has a lower resistance value than the heater electrode 250 and thus does not generate much heat.

[0075] Then, the third heater pattern 253 is connected in parallel to the second heater pattern 252 via this driver electrode 255. The driver electrode 255 is connected to an external power source via a connection terminal 270b. Specifically, a pad portion 253a is formed at one end of the third heater pattern 253, and this pad portion 253a and the driver electrode 255 are connected by a via 272. Then, the driver electrode 255 and the pad portion 250b, which is the end of the second heater pattern 252, are connected by a via 273. Also, the other end of the third heater pattern 253 is connected to the second heater pattern 252 within the plane in which the heater electrode 250 is formed. In this way, the third heater pattern 253 is connected in parallel to the second heater pattern 252 via the driver electrode 255 using the vias 272 and 273.

[0076] This makes it possible to increase the wiring freedom of the third heater pattern 253 and, consequently, the design freedom of the heater electrodes 250 and 50. In particular, when providing a plurality of heating zones Z1 and Z2 as in the present embodiment, it becomes easier to realize an optimal arrangement pattern of the heater electrodes 250 and 50.

[0077] Note that since the configuration of the heater electrode 50 disposed in the inner heating zone Z1 is the same as that in the first embodiment, the description thereof is omitted here.

[0078] The pad portions 50a and 50b of the heater electrode 50 are connected to an external power source via the connection terminals 70a and 70b. Also, the pad portion 250a of the heater electrode 250 is connected to the external power source via the connection terminal 270a, and the pad portion 250b of the heater electrode 250 is connected to the external power source via the via 273, the driver electrode 255, and the connection terminal 270b. Since the power supply to the heater electrodes 50 and 250 is independently controlled, the heating zones Z1 and Z2 are independently heated on the holding surface 11.

[0079] Also, in the case of the heater electrode 250, since the same effects as those in the first embodiment can be obtained, when forming the heater electrodes 50 and 250, even if there are variations in the thickness of the conductive paste during printing in the first region 61 and the second region 62, the temperature uniformity on the holding surface 11 can be improved. And in the present embodiment, a plurality of heater electrodes 50 and 250 are provided, and the regions of the holding surface 11 heated by each heater electrode are divided, so that the heating zones on the holding surface 11 are made into multiple zones, and thus the temperature uniformity on the holding surface 11 can be further improved. As a result, the temperature control on the holding surface 11 can be performed with high accuracy.

[0080] Here, in the present embodiment, a pair of connection terminals 70a and 70b are provided for the heater electrode 50, and a pair of connection terminals 270a and 270b are provided for the heater electrode 250. That is, a pair of connection terminals are provided separately for each heater electrode, but a part of the connection terminals can also be shared. For example, the connection terminals 70a and 270a can be shared. Specifically, as shown in FIG. 7, instead of the connection terminal 70a (see FIG. 6), a via 74 connected to the pad portion 50a is provided. Also, instead of the connection terminal 270a (see FIG. 6), a via 274 connected to the pad portion 250a is provided. Further, a driver electrode 257 connected to the vias 74 and 274 is provided. And a connection terminal 75 connected to this driver electrode 257 is provided. With such a connection terminal 75, the connection terminals 70a and 270a can be shared. Note that, as in FIG. 6, in FIG. 7, the heater electrode 50 is omitted except for the pad portions 50a and 50b.

[0081] Note that the above embodiments are merely examples and do not limit the present disclosure in any way. It goes without saying that various improvements and modifications can be made without departing from the gist thereof. For example, in the above embodiment, an electrostatic chuck including a base member is exemplified, but the present disclosure can also be applied to a holding device (e.g., a ceramic heater, etc.) that does not include a base member. When a heater electrode is provided in such a holding device without a base member, the heater electrode may be built in a plate-like member or may be provided on the lower surface (the surface opposite to the holding surface) without being built in the plate-like member.

[0082] Also, in the above first and second embodiments, cases where the first heater pattern and the second heater pattern each include a plurality of arc portions are exemplified, but the first heater pattern and the second heater pattern only need to each include at least one arc portion.

[0083] Also, in the above third embodiment, a two-zone pattern with two heating zones is exemplified, but a multi-zone pattern (such as a three-zone pattern or a four-zone pattern, etc.) with more than two heating zones may also be used.

Description of Symbols

[0084] 1 Electrostatic chuck 10 Plate-like member 11 Holding surface 12 Bottom surface 50 Heater electrode 50a Pad portion 50b Pad portion 51 First heater pattern 51a Arc portion 51b Arc portion 51c Arc portion 52 Second heater pattern 52a Arc portion 52b Arc portion 52c Arc portion 53 Third heater pattern 61 First region 62 Second region 150 Heater electrode 151 First heater pattern 152 Second heater pattern 153 Third heater pattern 250 Heater electrode 251 First heater pattern 252 Second heater pattern 253 Third heater pattern 255 Driver electrode W Semiconductor wafer (object) Z1 Inner heating zone Z2 Outer heating zone

Claims

1. A plate-like member including a first surface and a second surface provided in a direction opposite to the first surface in a first direction, and a heating resistor provided on the plate-like member and disposed on a plane substantially orthogonal to the first direction, In a holding device that holds an object on the first surface of the plate-like member, the heating resistor is a first heater pattern disposed in a first region including one end of the heating resistor and having an arc portion, a second heater pattern disposed in a second region different from the first region including the other end of the heating resistor and having an arc portion, and a third heater pattern connected in parallel to the second heater pattern, the first heater pattern and the second heater pattern are connected in series, the third heater pattern is disposed in the first region A holding device characterized by the above.

2. In the holding device according to claim 1, the third heater pattern is disposed along the first heater pattern A holding device characterized by the above.

3. In the holding device according to claim 1 or claim 2, the third heater pattern is connected to the second heater pattern via a driver electrode disposed on a plane different from the plane on which the heating resistor is disposed in the first direction and extending in a second direction substantially orthogonal to the first direction. A holding device characterized by the above.

4. In any one of the holding devices according to claims 1 to 3, each of the first heater pattern and the second heater pattern includes a plurality of arc portions displaced in a second direction substantially orthogonal to the first direction. A holding device characterized by the above.

5. In any one of the holding devices according to claims 1 to 4, a plurality of heating zones in which the heating resistor is disposed are provided. A holding device characterized by the above.

6. In any one of the holding devices according to claims 1 to 5, the arc portions in the first heater pattern and the second heater pattern have a length with a central angle of 180° to 270°. A holding device characterized by the above.

Images