Electrostatic chuck

Abstract

The invention provides an electrostatic chuck capable of suppressing local temperature rise of a heater. An electrostatic chuck (10) is provided with: a dielectric substrate (100); and a heater unit (300) that heats the dielectric substrate (100). The heater unit (300) is provided with: a power supply unit (390) that receives power supply from the outside; a heat-generating unit (331) which is a conductor arranged in a linear surrounding manner and which generates heat by receiving power supplied from the power supply unit (390); and a bypass layer (370) that connects the power supply unit (390) and the heat generation unit (331). The heat generating section (331) has a widened section (332), which is a section in which the line width thereof is locally enlarged. The bypass layer (370) is connected to the heat generating part (331) at a plurality of locations of the widened part (332).

Description

Technical Field

[0001] The invention relates to an electrostatic chuck. Background Art

[0002] For example, in a semiconductor manufacturing device such as an etching device, an electrostatic chuck is provided as a device for adsorbing and holding a substrate such as a silicon wafer to be processed. The electrostatic chuck has a dielectric substrate provided with an adsorption electrode. When a voltage is applied to the adsorption electrode, an electrostatic force is generated to adsorb and hold the substrate placed on the dielectric substrate.

[0003] When a substrate is processed by a semiconductor manufacturing device, it is necessary to adjust the temperature so that the temperature distribution in the surface of the substrate is as uniform as possible. In order to achieve high-precision temperature adjustment, an electrostatic chuck with a heater has been developed in recent years and has been put into practical use. Although the heater is sometimes set inside the dielectric substrate, it is sometimes set between the dielectric substrate and the base plate in a unitized state, as described in the following patent document 1.

[0004] Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2021-197485 Summary of the invention

[0005] The heater includes, for example, a power supply portion such as a power supply terminal and a heat generating portion which is a conductor arranged in a linear manner. When electric power is supplied from the outside to the power supply portion and current flows through the heat generating portion, Joule heat is generated in the heat generating portion.

[0006] It is preferred that the power supply unit and the heat generating unit be connected via a bypass unit in the middle, rather than being directly connected. The presence of the bypass unit in the middle can increase the degree of freedom in the arrangement of the power supply unit in the heater.

[0007] At this time, a part of the bypass portion is connected to the heat generating portion by welding, for example. Hereinafter, the portion of the heat generating portion to which the bypass portion is connected is also referred to as a "connection portion". When the heater generates heat, the current passes through the narrow connection portion, so a local temperature rise may occur in the connection portion. As a result, the in-plane temperature distribution of the substrate during processing tends to be uneven, and there is a concern that it may have a bad effect on the processing.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrostatic chuck capable of suppressing a local temperature increase of a heater.

[0009] In order to solve the above problems, the electrostatic chuck involved in the present invention has: a dielectric substrate; and a heater for heating the dielectric substrate. The heater has: a power supply part that receives power supply from the outside; a heating part that is a conductor arranged in a linear shape and receives power from the power supply part to generate heat; and a bypass part that connects the power supply part and the heating part. The heating part has a part that partially enlarges its line width, namely a widening part. The bypass part is connected to the heating part at multiple locations of the widening part.

[0010] In the electrostatic chuck having such a structure, the current supplied to the heat generating portion flows through a path passing through a portion of the widened portion connected to the bypass portion. Hereinafter, this portion is also referred to as a "connecting portion."

[0011] The bypass part is connected to the heat generating part at multiple locations of the widening part. That is, there are multiple such connecting parts in one widening part. In such a configuration, the current supplied from the bypass part to the heat generating part does not flow in a single connecting part, but is dispersed in multiple connecting parts. Since the Joule heat generated in one connecting part can be reduced, the local temperature rise in the connecting part can be suppressed.

[0012] According to the present invention, it is possible to provide an electrostatic chuck capable of suppressing a local temperature increase of a heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view schematically showing the structure of the electrostatic chuck according to the present embodiment. Figure 2 This is an exploded view schematically showing the structure of the heater unit. Figure 3 It is a diagram showing an example of arrangement of the auxiliary heater layer in the heater unit. Figure 4 It is a diagram showing the structure of one auxiliary heater layer. Figure 5 It is a diagram showing an example of arrangement of a main heater layer in a heater unit. Figure 6 It is a diagram showing the structure of one main heater layer. Figure 7 This is a diagram for explaining the role of the bypass layer, etc. Figure 8 It is a cross-sectional view showing the structure of a welded portion and its surroundings in the heater unit. Fig. 9 It is a diagram showing an example of arrangement of the connection portion in the widened portion. Fig.10 It is a diagram showing an example of arrangement of the connection portion in the widened portion. Fig.11It is a diagram showing an example of arrangement of the connection portion in the widened portion. Fig.12 It is a diagram showing an example of arrangement of the connection portion in the widened portion. Fig.13 It is a diagram showing an example of arrangement of the connection portion in the widened portion. Explanation of symbols 10-electrostatic suction cup; 100-dielectric substrate; 300-heater unit; 301A-connecting portion; 331, 351-heating portion; 332, 333, 352, 353-widening portion; 370-bypass layer; 390-power supply portion; BD-boundary portion; BD1-first boundary portion; BD2-second boundary portion. DETAILED DESCRIPTION

[0014] Hereinafter, the present embodiment will be described with reference to the drawings. In order to facilitate the description, the same components are denoted by the same reference numerals as much as possible in each of the drawings, and repeated descriptions are omitted.

[0015] For example, in a semiconductor manufacturing apparatus (not shown) such as an etching apparatus, the electrostatic chuck 10 according to the present embodiment uses electrostatic force to attract and hold a substrate W to be processed. The adsorbed substrate W is, for example, a silicon wafer. The electrostatic chuck 10 can also be used in apparatuses other than semiconductor manufacturing apparatuses.

[0016] Figure 1 2 shows a schematic cross-sectional view of the structure of the electrostatic chuck 10 in a state of sucking and holding the substrate W. The electrostatic chuck 10 includes a dielectric substrate 100 , a susceptor plate 200 , and a heater unit 300 .

[0017] The dielectric substrate 100 is a roughly disk-shaped member composed of a ceramic sintered body. The dielectric substrate 100 contains, for example, high-purity aluminum oxide (Al2O3), but may also contain other materials. The purity and type of ceramics in the dielectric substrate 100, additives, etc. may be appropriately set in consideration of the plasma resistance required of the dielectric substrate 100 in the semiconductor manufacturing device.

[0018] In the dielectric substrate 100, Figure 1 The upper surface 110 in the dielectric substrate 100 is a "placing surface" on which the substrate W is placed. Figure 1 The lower surface 120 in FIG. 1 is a “bonded surface” bonded to the heater unit 300 via the bonding layer 410. Hereinafter, the viewpoint when the electrostatic chuck 10 is observed from the surface 110 side in a direction perpendicular to the surface 110 is also referred to as “top view”.

[0019] An adsorption electrode 130 is embedded inside the dielectric substrate 100. The adsorption electrode 130 is a relatively thin flat layer formed of a metal material such as tungsten, and is arranged parallel to the surface 110. As a material for the adsorption electrode 130, in addition to tungsten, molybdenum, platinum, palladium, etc. can also be used. If a voltage is applied to the adsorption electrode 130 from the outside through a power supply circuit (not shown), an electrostatic force is generated between the surface 110 and the substrate W, thereby the substrate W is adsorbed and held. As the structure of the above-mentioned power supply circuit, various known structures can be adopted. The adsorption electrode 130 can be provided as only one so-called "monopolar" electrode as in the present embodiment, or two so-called "bipolar" electrodes can be provided.

[0020] like Figure 1 As shown in FIG. 1 , a space SP is formed between the dielectric substrate 100 and the substrate W. When etching or other processing is performed in the semiconductor manufacturing apparatus, helium gas for temperature adjustment is supplied from the outside to the space SP through a gas hole (not shown). By making the helium gas exist between the dielectric substrate 100 and the substrate W, the thermal resistance between the two is adjusted, so that the temperature of the substrate W is maintained at an appropriate temperature. In addition, the gas for temperature adjustment supplied to the space SP may be a gas of a different type from helium.

[0021] A sealing ring 111 and points 112 are provided on the surface 110 which is the placement surface, and the above-mentioned space SP is formed around these surfaces.

[0022] The sealing ring 111 is a wall that divides the space SP at the position that becomes the outermost periphery. The upper end of the sealing ring 111 becomes a part of the surface 110 and abuts against the substrate W. In addition, a plurality of sealing rings 111 may be provided in a manner that divides the space SP. With such a structure, the pressure of the helium gas in each space SP can be adjusted separately, and the surface temperature distribution of the substrate W can be made uniform during processing.

[0023] Figure 1 In FIG. 1 , the portion marked with the symbol “116” is the bottom surface of the space SP. Hereinafter, this portion is also referred to as “bottom surface 116”. The sealing ring 111 is formed as a result of digging out a portion of the surface 110 to the position of the bottom surface 116 together with the point 112 described below.

[0024] The dots 112 are circular protrusions protruding from the bottom surface 116. A plurality of dots 112 are provided and are dispersed approximately evenly on the placement surface of the dielectric substrate 100. The upper end of each dot 112 becomes a part of the surface 110 and contacts the substrate W. By providing a plurality of such dots 112, the substrate W is prevented from being bent.

[0025] The base plate 200 is a substantially disk-shaped member that supports the dielectric substrate 100 and the heater unit 300. The base plate 200 is formed of a metal material such as aluminum. Figure 1 The upper surface 210 in the figure becomes a “joined surface” joined to the heater unit 300 via the joining layer 420 .

[0026] A cooling medium flow path 250 for flowing a cooling medium is formed inside the susceptor plate 200. When etching or other processing is performed in the semiconductor manufacturing apparatus, a cooling medium is supplied from the outside to the cooling medium flow path 250, thereby cooling the susceptor plate 200. During the processing, heat generated on the substrate W is transferred to the cooling medium via the helium gas in the space SP, the dielectric substrate 100, and the susceptor plate 200, and is discharged to the outside together with the cooling medium.

[0027] An insulating film may be formed on the surface of the base plate 200. As the insulating film, for example, an aluminum oxide film formed by thermal spraying may be used. By covering the surface of the base plate 200 with the insulating film, the dielectric withstand voltage of the base plate 200 can be improved.

[0028] The heater unit 300 receives power from the outside to generate heat, thereby heating the dielectric substrate 100. As described later, the heater unit 300 is provided with a plurality of heating portions 331, etc., and the heat generation of each heating portion 331, etc. can be adjusted individually. By adjusting the heat generation of each portion individually, the temperature distribution in the surface of the substrate W can be made nearly uniform during processing.

[0029] The heater unit 300 is sandwiched between the dielectric substrate 100 and the base plate 200, and is bonded to the dielectric substrate 100 and the base plate 200, respectively. The heater unit 300 is bonded to the dielectric substrate 100 by a bonding layer 410, and the heater unit 300 is bonded to the base plate 200 by a bonding layer 420. The bonding layers 410 and 420 are, for example, layers formed by curing a silicone adhesive. A plurality of granular fillers (fillers) for improving thermal conductivity are arranged inside each. As the filler, for example, particles containing aluminum oxide as a main component are used.

[0030] The specific structure of the heater unit 300 will be described. Figure 2, the structure of the heater unit 300 is shown as a schematic exploded assembly diagram. As shown in the figure, the heater unit 300 includes a support plate 310 (310A), an insulating layer 320, an auxiliary heater layer 330, an insulating layer 340, a main heater layer 350, an insulating layer 360, a bypass layer 370, an insulating layer 380, a support plate 310 (310B), and a power supply unit 390. In addition, in the present embodiment, the auxiliary heater layer 330, the main heater layer 350, and the bypass layer 370 are arranged in order from the top, but the arrangement order of these may be different from the order of the present embodiment.

[0031] The support plates 310 are substantially disk-shaped members and are disposed in the heater units 300. Figure 2 The following will be set at the upper and lower ends of Figure 2 The support plate 310 at the upper side end is also referred to as "support plate 310A". Figure 2 The support plate 310 at the lower end portion is also referred to as a “support plate 310B.” The support plate 310A is a portion bonded to the dielectric substrate 100 via the bonding layer 410 , and the support plate 310B is a portion bonded to the base plate 200 via the bonding layer 420 .

[0032] The pair of support plates 310A and 310B are members for reinforcing the heater unit 300 as a whole by sandwiching the auxiliary heater layer 330, the main heater layer 350, and the bypass layer 370. In the present embodiment, although the support plates 310A and 310B are both formed of metal, they may also be formed of other members (e.g., insulating members). As will be described later, although the openings 311 are formed in the support plates 310A and 310B, Figure 2 The illustration is omitted.

[0033] The insulating layer 320 is provided between the support plate 310A and the auxiliary heater layer 330, and is used to electrically insulate the two. In addition, the insulating layer 320 also has the function of physically bonding the two. Although the insulating layer 320 is a polyimide film in this embodiment, it can contain components other than polyimide, and can also be formed of a material different from polyimide. When the support plate 310A is formed of an insulating material, the insulating layer 320 can also be omitted.

[0034] The auxiliary heater layer 330 is a portion that receives power from the outside to generate heat. Figure 2 In the figure, the auxiliary heater layer 330 is schematically depicted as a single circular plate, but in fact, the auxiliary heater layer 330 is divided into a plurality of regions, and each region can generate heat independently. The specific structure of the auxiliary heater layer 330 will be described later.

[0035] The insulating layer 340 is provided between the auxiliary heater layer 330 and the main heater layer 350 to electrically insulate the two. In addition, the insulating layer 340 also has the function of physically connecting the two. Although the insulating layer 340 is a polyimide film in this embodiment, it may contain components other than polyimide, or may be formed of a material other than polyimide.

[0036] Similar to the auxiliary heater layer 330 described above, the main heater layer 350 is a portion that generates heat by receiving power supplied from the outside. Figure 2 In the figure, the main heater layer 350 is schematically depicted as a single circular plate, but in reality, the main heater layer 350 is divided into a plurality of regions, and each region can generate heat independently. The specific structure of the main heater layer 350 will be described later.

[0037] The main heater layer 350 generates more heat than the auxiliary heater layer 330 described above. The main heater layer 350 is used to increase the temperature of the entire dielectric substrate 100 in a short time. The auxiliary heater layer 330 is used to adjust the temperature of each part of the dielectric substrate 100 so that the temperature distribution in the surface of the substrate W is close to uniform. As described above, in this embodiment, two heater layers corresponding to their respective functions are separately provided. Instead of such a form, it is also possible to configure that only one heater layer is provided.

[0038] The insulating layer 360 is provided between the main heater layer 350 and the bypass layer 370 to electrically insulate the two. In addition, the insulating layer 360 also has the function of physically bonding the two. Although the insulating layer 360 is a polyimide film in this embodiment, it may contain components other than polyimide or may be formed of a material other than polyimide.

[0039] The bypass layer 370 is a layer for electrically connecting a power supply unit 390 to be described later and the auxiliary heater layer 330 or the main heater layer 350 . Figure 2 In the figure, although the bypass layer 370 is schematically depicted as a single circular plate, in fact, the bypass layer 370 is divided into a plurality of parts. By providing the bypass layer 370 in the middle of the circuit connected to the auxiliary heater layer 330, etc., the position of the power supply unit 390 can be adjusted. Parts of the divided bypass layers 370 are welded to the auxiliary heater layer 330 or the main heater layer 350. The divided bypass layers 370 correspond to the "bypass parts" in this embodiment.

[0040] The insulating layer 380 is provided between the bypass layer 370 and the support plate 310B and is used to electrically insulate the two. In addition, the insulating layer 380 also has the function of physically bonding the two. Although the insulating layer 380 is a polyimide film in this embodiment, it can contain components other than polyimide and can also be formed of a material other than polyimide. When the support plate 310B is formed of an insulating material, the insulating layer 380 can also be omitted.

[0041] When manufacturing the heater unit 300, Figure 2 In the state where the layers shown are stacked, the entirety of the layers is pressed and heated, so that the entirety is bonded together by the polyimide film, that is, the insulating layer 320, etc.

[0042] The power supply unit 390 is a part that receives power required for generating heat from the auxiliary heater layer 330 and the like from the outside. In the present embodiment, the power supply unit 390 is formed as a long and thin rod-shaped plug, and one end thereof is connected to the bypass layer 370. Although a plurality of power supply units 390 are provided depending on the number of bypass layers 370, Figure 2 Only two of them are shown in the figure. Through holes (not shown) are formed at positions of the base plate 200 corresponding to the power supply parts 390, and the power supply parts 390 pass through the through holes.

[0043] The structure of the auxiliary heater layer 330 will be described. As described above, the auxiliary heater layer 330 is divided into a plurality of regions, and each region can generate heat independently. Figure 3 , an example of a division method of the auxiliary heater layer 330 in a plan view is shown. In this example, the auxiliary heater layer 330 is divided into a total of 24 areas HA.

[0044] Each of the divided auxiliary heater layers 330 is configured as a linear heat generating portion 331 and is individually arranged in a surrounding manner in each area HA. ​​The heat generating portion 331 is a conductor arranged in a surrounding manner in a linear manner, and receives power from the power supply portion 390 to generate heat. Figure 4 , an example of a heat generating portion 331 surrounded and arranged in one area HA is shown. In each area HA, one linear heat generating portion 331 is surrounded and arranged on a path that passes substantially the entire area evenly. Two or more heat generating portions 331 connected in parallel to each other may also be surrounded and arranged.

[0045] Circular widening portions 332 and 333 are formed at both ends of the heat generating portion 331. The widening portions 332 and 333 are both parts of the heat generating portion 331, and are the parts where the line width is partially enlarged. The widening portions 332 and 333 are the parts electrically connected to the bypass layer 370 by the welding portion 301 described later. The shape of the widening portions 332 and 333 can be a circle as in the present embodiment, or a shape other than a circle.

[0046] The heat generating portion 331 including the widened portions 332 and 333 is formed by etching a thin metal foil, for example, and the entire portion functions as one auxiliary heater layer 330. In other words, one auxiliary heater layer 330 is provided for each of the 24 areas HA in total.

[0047] and, Figure 4 The shape of the auxiliary heater layer 330 shown is a schematic shape and is different from the actual shape. For example, the auxiliary heater layer 330 such as the widened portion 332 may be provided in the middle of the heat generating portion 331 instead of being provided at the end of the heat generating portion 331 .

[0048] The structure of the main heater layer 350 will be described. Similar to the auxiliary heater layer 330, the main heater layer 350 is also divided into a plurality of regions, and each region can generate heat independently. Figure 5 , an example of a division method of the main heater layer 350 in a plan view is shown. In this example, the main heater layer 350 is divided into a total of three areas HB.

[0049] Each of the divided main heater layers 350 is configured as a linear heat generating portion 351 and is individually arranged in each area HB. Similar to the heat generating portion 331, the heat generating portion 351 is a conductor arranged in a linear manner and receives power from the power supply portion 390 to generate heat. Figure 6 , an example of a heat generating portion 351 surrounded and arranged in one area HB is shown. In each area HB, one linear heat generating portion 351 is surrounded and arranged on a path that passes substantially the entire area evenly. Two or more heat generating portions 351 connected in parallel to each other may also be surrounded and arranged.

[0050] Circular widening portions 352 and 353 are formed at both ends of the heat generating portion 351. The widening portions 352 and 353 are both parts of the heat generating portion 351, and are the parts where the line width is partially enlarged. The widening portions 352 and 353 are the parts electrically connected to the bypass layer 370 via the welding portion 301. The shape of the widening portions 352 and 353 can be a circle as in the present embodiment, or a shape other than a circle.

[0051] The heat generating portion 351 including the widened portions 352 and 353 is formed by etching a thin metal foil, for example, and the entire portion functions as one main heater layer 350. In other words, one main heater layer 350 is provided for each of the three regions HB in total.

[0052] and, Figure 6 The shape of the main heater layer 350 shown is a schematic shape and is different from the actual shape. For example, the main heater layer 350 may have a widened portion 352 disposed in the middle of the heat generating portion 351 instead of being disposed at the end of the heat generating portion 351 .

[0053] Figure 7 , the structure of two areas HA, two auxiliary heater layers 330 arranged thereon, and a bypass layer 370 connected to the auxiliary heater layer 330 is shown as a schematic three-dimensional diagram. Figure 7 One of the two areas HA shown is also referred to as "area HA1". Hereinafter, the other area HA is also referred to as "area HA2". Figure 7 The shapes of the heat generating portion 331 and the like shown are schematic shapes and are different from actual shapes.

[0054] As described above, the bypass layer 370 is divided into a plurality of parts. Figure 7 In the figure, only three of the bypass layers 370 divided into a plurality of parts are shown. In the bypass layers 370 divided into three parts, Figure 7 The bypass layer denoted by the symbol "371" is arranged at a position overlapping only one area HA when viewed from above. In other words, it is arranged alone at a position directly below each area HA. ​​Hereinafter, the portion of the bypass layer 370 arranged in this way is also referred to as "bypass layer 371".

[0055] In the divided bypass layer 370, Figure 7 The bypass layer denoted by reference numeral “ 372 ” is arranged at a position overlapping both the region HA1 and the region HA2 in a plan view. Hereinafter, the portion of the bypass layer 370 arranged in this manner is also referred to as a “bypass layer 372 ”.

[0056] In the auxiliary heater layer 330 disposed in the area HA1 , the widened portion 332 at one end of the heat generating portion 331 is electrically connected to the bypass layer 371 located directly therebelow. The widened portion 333 at the other end of the heat generating portion 331 is electrically connected to the bypass layer 372 .

[0057] In the auxiliary heater layer 330 disposed in the area HA2 , the widened portion 332 at one end of the heat generating portion 331 is electrically connected to the bypass layer 371 located directly therebelow. The widened portion 333 at the other end of the heat generating portion 331 is electrically connected to the bypass layer 372 .

[0058] Furthermore, in this embodiment, the electrical connection of the above-mentioned parts is achieved by welding the upper and lower layers to each other. Figure 7 In the figure, each welding portion is schematically depicted as a rod-shaped member extending in a straight line (the portion marked with the symbol 301), but the actual shape of the welding portion is different from this. In addition, in the portion overlapping with each welding portion when viewed from above, openings are respectively provided on each layer (insulating layer 340, main heater layer 350, and insulating layer 360) between the auxiliary heater layer 330 and the bypass layer 370, and the auxiliary heater layer 330 and the bypass layer 370 directly overlap through the openings.

[0059] from Figure 7 Below, one end of the power supply unit 390 is connected to each bypass layer 371. A voltage is applied to each of the power supply units 390 from an external DC power supply. Figure 7 Below, one end of the power supply portion 390 is also connected to the bypass layer 372. The power supply portion 390 is grounded.

[0060] As described above, in the auxiliary heater layer 330 (heat generating portion 331 ) provided in each area HA, the widened portion 332 is connected to a separate DC power source via the bypass layer 371 , and the widened portion 333 is grounded via the common bypass layer 372 . Figure 7 The other auxiliary heater layers 330 not shown in the figure are connected to a DC power supply etc. by the same structure. By making such a structure, power can be supplied to each of the auxiliary heater layers 330 provided in plurality, and the heat generation in each part can be adjusted.

[0061] The auxiliary heater layer 330 may be supplied with power directly from the power supply unit 390 instead of through the bypass layer 370. However, by adopting a structure in which power is supplied through the bypass layer 370 as in the present embodiment, the power supply unit 390 can be arranged with greater freedom, or the grounded power supply units 390 can be concentrated in one.

[0062] The power supply to each main heater layer 350 is also realized by the same structure as above. Figure 7The bypass layer 370 connected to the auxiliary heater layer 330 and the bypass layer 370 connected to the main heater layer 350 may be arranged at the same height as in the present embodiment ( Figure 2 The bypass layer 370 may be arranged at different heights.

[0063] As described above, in the heater unit 300, the auxiliary heater layer 330 and the bypass layer 370 are electrically connected by welding. Hereinafter, such a welded portion is also referred to as a "welded portion 301".

[0064] Figure 8 3 is a cross-sectional view showing the structure of the welding portion 301 and its surroundings in the heater unit 300. Figure 8 As shown, in a part of the heater unit 300, the auxiliary heater layer 330 and the bypass layer 370 are not overlapped with each other by the insulating layers 340, 360 and the main heater layer 350, and on this basis, the two are connected as one body by, for example, resistance spot welding. The part inside the widened parts 332, 333 of the heat generating part 331 is connected to the bypass layer 370 by the welding part 301.

[0065] In this embodiment, if Figure 8 As shown, the two welding parts 301 are formed at positions close to each other. That is, in fact, in each widened part 332 (or widened part 333), Figure 7 The number of welded portions 301 shown is two. Furthermore, the number of welded portions 301 arranged close to each other on the inner side of one widened portion 332 may be more than three. The number and interval of welded portions 301 may be appropriately set according to the welding method used.

[0066] As described above, the auxiliary heater layer 330 and the bypass layer 370 are welded, and then the auxiliary heater layer 330 is sandwiched by a pair of support plates 310. The welded portion 301 bulges as described above. Figure 8 The welding portion 301 protrudes toward the upper side of the insulating layer 320 and the lower side of the insulating layer 380. Therefore, when the auxiliary heater layer 330 and the like are clamped as a whole by a pair of support plates 310, depending on the size of the welding portion 301, the welding portion 301 may contact the support plate 310 and the outer surface of the support plate 310 may be deformed in a partially protruding manner.

[0067] Therefore, in the electrostatic chuck 10 according to the present embodiment, an opening 311 is formed in the support plate 310 at a position opposite to the welding portion 301. The opening 311 is a circular opening, and when viewed from above, the two welding portions 301 are accommodated inside one opening 311. Since the welding portion 301 does not abut against the support plate 310, even if a portion of the welding portion 301 bulges, the support plate 310 will not be deformed.

[0068] The opening 311 may be formed on both sides of the pair of support plates 310A and 310B, or may be formed on only one of them. However, if the opening 311 is formed on both sides of the support plates 310A and 310B as in the present embodiment, deformation of the support plate 310 can be prevented on both sides of the heater unit 300, which is more preferred.

[0069] Fig. 9 , the structure near the widening portion 332 located at the end of the heat generating portion 331 when viewed from above is shown. As described above, the widening portion 332 is connected to the bypass layer 370 via two welding portions 301. Hereinafter, the portion of the widening portion 332 where the welding portion 301 is provided, that is, the portion of the widening portion 332 connected to the bypass layer 370 is also referred to as the "connection portion 301A".

[0070] In this embodiment, two or more connection portions 301A are provided in each of the widened portions 332 and the like of the heat generating portion 331. In other words, the bypass layer 370 is connected to the heat generating portion 331 at a plurality of locations inside each widened portion 332 and the like.

[0071] Assuming that only one connection portion 301A is provided inside the widened portion 332, when the heater unit 300 generates heat, current flows through the relatively narrow connection portion 301A, so that a local temperature rise may occur in the connection portion 301A. As a result, the in-plane temperature distribution of the substrate W during processing tends to be non-uniform, which may adversely affect the processing.

[0072] Therefore, in this embodiment, as described above, the bypass layer 370 is connected to the heat generating portion 331 at multiple locations of the widened portion 332. In such a structure, the current supplied from the bypass layer 370 to the widened portion 332 of the heat generating portion 331 does not flow in a single connection portion 301A, but flows in a plurality of connection portions 301A. Since the Joule heat generated in one connection portion 301A is small, the local temperature rise in the connection portion 301A can be suppressed.

[0073] Fig. 9In the figure, the dotted line marked with the symbol "BD" indicates the boundary between the widened portion 332 in the heat generating portion 331 and the other portions thereof. Hereinafter, such a boundary portion is also referred to as "boundary portion BD". Fig. 9 The dashed line DL shown is a line passing through the centers of the two connection portions 301A located inside the widened portion 332. The dashed line DL indicates the arrangement direction of the two connection portions 301A.

[0074] Fig. 9 The arrow AR1 shown indicates the direction from the center CT of the widened portion 332 toward the boundary portion BD. Specifically, the "direction toward the boundary portion BD" is the direction toward the center of the width direction of the boundary portion BD. Furthermore, when the shape of the widened portion 332 when viewed from above is other than a circle, the "center CT of the widened portion 332" is the center of gravity of the widened portion 332.

[0075] In this embodiment, the dot-dash line DL is along Fig. 9 That is, the pair of connection parts 301A located in the widening part 332 are arranged to be arranged along the direction perpendicular to the direction from the center CT of the widening part 332 toward the boundary part BD (that is, the direction of the dot-dash line DL).

[0076] In such a structure, the magnitude of the current flowing from the respective connection portions 301A to the boundary portion BD can be made substantially equal. Since the current does not flow intensively in one connection portion 301A, it is possible to further suppress a local temperature rise in the connection portion 301A.

[0077] As described above, in the present embodiment, a plurality of connection portions 301A are provided in one widened portion 332 , and the specific arrangement of these connection portions 301A is studied, thereby sufficiently suppressing the occurrence of a local temperature rise.

[0078] Furthermore, the number of the connection parts 301A provided in one widened part 332 may be more than three. Fig.10 In the example shown, four connection portions 301A are provided in one widened portion 332. Specifically, two pairs of connection portions 301A are provided in one widened portion 332, arranged in a direction perpendicular to the arrow AR1 (dotted line DL). Fig. 9 or Fig.10 As in the example, the plurality of connection portions 301A located in the widening portion 332 may include at least one pair of connection portions 301A arranged along a direction perpendicular to the direction from the center CT of the widening portion 332 toward the boundary portion BD.

[0079] exist Fig.10In the example, the distances between a pair of connection portions 301A arranged along the dashed line DL are the same in each group. As a result, the four connection portions 301A are arranged at the positions of the vertices of the rectangle. With such a structure, while maintaining the balance of the current of each connection portion 301A, the bonding strength between the widening portion 332 and the bypass layer 370 can be fully ensured. The shape formed by connecting the centers of the four connection portions 301A can be a rectangle as in the present embodiment, but can also be a square.

[0080] As described above, the widened portion 332 and the like may be formed at the end of the heat generating portion 331 extending linearly, or may be formed in the middle of the heat generating portion 331 . Fig.11 , an example of the arrangement of the connection portion 301A in the widening portion 332 formed at a position in the middle of the heat generating portion 331 is shown. In this example, two boundary portions BD are adjacent to one widening portion 332. Hereinafter, one boundary portion BD is also referred to as "first boundary portion BD1". Hereinafter, the other boundary portion BD is also referred to as "second boundary portion BD2".

[0081] Fig.11 The arrow AR2 shown indicates the direction from the first boundary BD1 toward the second boundary BD2. Specifically, the direction from the first boundary BD1 toward the second boundary BD2 is the direction from the center of the first boundary BD1 in the width direction toward the center of the second boundary BD2 in the width direction.

[0082] exist Fig.11 In the example, the respective connection parts 301A are arranged so that the dot-dash line DL extends in a direction perpendicular to the direction indicated by the arrow AR2. Fig.11 The plurality of connection portions 301A of the widening portion 332 include a pair of connection portions 301A arranged to be arranged along a direction perpendicular to the direction from the first boundary portion BD1 toward the second boundary portion BD2 (that is, the direction of the dashed line DL). Fig.11 In the example, there are two pairs of such connecting portions 301A, and Fig.10 Similarly to the example of , four connection parts 301A are arranged at the positions forming the vertices of the rectangle. A pair of connection parts 301A arranged in the direction of the dot-dash line DL may be only one set.

[0083] The direction of the arrow AR2 can also be referred to as the direction in which the current flowing along the linear heating portion 331 flows when it passes through the widened portion 332. Fig.11In the example, by arranging a pair of connection portions 301A along a direction perpendicular to such a direction (that is, the direction of the dot-dash line DL), the current flowing from each connection portion 301A into the heat generating portion 331 can be made substantially equal.

[0084] And, even in the Fig.11 In the widened portion 332 having two boundary portions BD, Fig. 9 At this time, the pair of connecting portions 301A located in the widening portion 332 may be arranged along a direction perpendicular to the direction from the center CT of the widening portion 332 toward any boundary portion BD (that is, the direction of the dot-dash line DL).

[0085] Even when three or more boundary portions BD are adjacent to one widening portion 332, the connecting portion 301A may be arranged in the same manner as in any of the examples described above. Fig.12 In the example shown, the configuration is Fig.11 In the example, a boundary portion BD (third boundary portion BD3) is added, and the rest of the structure is the same as Fig.11 Like this, when three boundary portions BD are adjacent to one widening portion 332, by Fig.10 The pair of connecting portions 301A can be configured in the same manner as in the example without being affected by the third boundary portion BD3. Fig. 9 The connection portion 301A is configured in the same manner as in the example.

[0086] The shape of the widened portion 332 when viewed from above may be other than circular. Fig.13 In the example of FIG. 1 , the shape of the widened portion 332 is a shape that becomes longer and longer along the dashed line DL, which is different from the Fig. 9 In a pair of connection parts 301A arranged along the dashed line DL, when one is referred to as the "first connection part" and the other as the "second connection part", Fig.13 The widened portion 332 is formed to extend from the first connecting portion toward the second connecting portion.

[0087] In such a configuration, the shape of the widened portion 332 can be formed to include the respective connecting portions 301A while minimizing the area. The widened portion 332 is a portion of the heating portion 331 that generates less heat. Since the size of such a widened portion 332 is minimized, the heating efficiency of the heater unit 300 can be fully ensured.

[0088] Set in Fig.13 The number of connecting portions 301A of the widening portion 332 of the shape shown in FIG. Fig.10In the same way as in the example, four connecting parts 301A can be provided and arranged at the positions of the vertices of the rectangle. In this case, on the basis of arranging the connecting parts 301A, the shape of the widening part 332 can be made into a shape extending along the long side direction of the rectangle, so that the shape formed by connecting the centers of the four connecting parts 301A becomes a rectangle.

[0089] Although the configuration of the connection portion 301A in the widened portion 332 is described above, the same configuration as above may be adopted for the configuration of the connection portion 301A in the widened portion 333. In addition, the same configuration as above may be adopted for the connection portion between the main heater layer 350 and the bypass layer 370.

[0090] The above description has been made of a structure in which a heater for heating the dielectric substrate 100 is provided outside the dielectric substrate 100 in a unitized state as the heater unit 300. However, the above-described structure can also be applied to a structure in which the heater is provided inside the dielectric substrate 100.

[0091] That is, it is also possible to make a form in which the heating portion 331 composed of conductors arranged in a linear manner is buried inside the dielectric substrate 100 as a heater. In this case, the power supply portion 390 is provided on the surface 120 side of the dielectric substrate 100, and the bypass layer 370 connecting the power supply portion 390 and the heating portion 331 is buried inside the dielectric substrate 100 in the same manner as the heating portion 331. The connection between the bypass layer 370 and the heating portion 331 is not achieved through the welding portion 301 as in the present embodiment, but can be achieved by a slender via (hole) filled with a conductor. On this basis, the configuration of the portion of the widened portion 332 etc. connected to the above-mentioned via (that is, the portion equivalent to the connecting portion 301A) can be configured to be the same as any of the examples described above.

[0092] Above, the present embodiment has been described with reference to specific examples. However, the present invention is not limited to these specific examples. With regard to these specific examples, as long as they have the characteristics of the present invention, the technology that is appropriately designed and changed by those skilled in the art is also included in the scope of the present invention. The various elements and their configurations, conditions, shapes, etc. possessed by the aforementioned specific examples are not limited to the illustrated contents, but can be appropriately changed. As long as there is no technical contradiction, the various elements possessed by the aforementioned specific examples can be appropriately changed and combined.

Claims

1. An electrostatic chuck, characterized in that: Possessing: a dielectric substrate; and a heater to heat the dielectric substrate, The heater comprises: a power supply unit for receiving power supply from the outside; A heating part, which is a conductor arranged in a linear manner and generates heat by receiving the power supplied from the power supply part; and a bypass portion connected between the power supply portion and the heating portion, The heat generating portion has a portion where its line width is partially enlarged, i.e., a widening portion. The bypass portion is connected to the heat generating portion at a plurality of locations of the widened portion.

2. The electrostatic chuck according to claim 1, characterized in that: In the heat generating portion, when the boundary between the widened portion and other portions thereof is regarded as the boundary portion, When the portion of the widened portion connected to the bypass portion is used as the connecting portion, The plurality of connecting portions located at the widening portion, The invention includes a pair of the connection portions arranged side by side in a direction perpendicular to a direction from a center of the widened portion toward the boundary portion.

3. The electrostatic chuck according to claim 1, wherein: In the heat generating portion, when the boundary between the widened portion and other portions thereof is regarded as the boundary portion, When the portion of the widened portion connected to the bypass portion is used as the connecting portion, A plurality of the boundary portions including the first boundary portion and the second boundary portion are adjacent to one of the widened portions, The plurality of connecting portions located at the widened portion, The invention includes a pair of the connection parts arranged side by side in a direction perpendicular to a direction from the first boundary part toward the second boundary part.

4. The electrostatic chuck according to claim 1, wherein: When the portion of the widened portion connected to the bypass portion is used as the connecting portion, The plurality of connection parts located at the widened part include a first connection part and a second connection part, The widened portion is formed to extend from the first connecting portion toward the second connecting portion.

5. The electrostatic chuck according to any one of claims 2 to 4, characterized in that: In the widened portion, the four connecting portions are arranged at positions forming vertices of a rectangle.

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