Electrostatic Chuck Device

Abstract

To provide an electrostatic chuck device which can significantly improve, compared with a conventional device, cooling performance of an object to be sucked while adapting to an increase in size of a substrate.SOLUTION: An electrostatic chuck device for sucking an object with electrostatic force comprises: a suction plate 1 whose front side serves as a suction surface for sucking the object; and a base plate 2 having an internal flow path in which a coolant flows. The internal flow path 21 includes: a radial flow path L2 in which the coolant flows radially from a central portion to an outer peripheral portion of the base plate 2; and a concentration flow path L4 in which the coolant flows from the outer peripheral portion of the base plate 2 in a manner concentrating on the central portion. Inside the base plate 2, the radial flow path L2 and the concentration flow path L4 are formed in a stacking manner.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrostatic chuck device that attracts an object by electrostatic force. [Background technology]

[0002] Conventionally, in semiconductor manufacturing processes using plasma processing equipment such as plasma etching equipment and plasma CVD equipment, electrostatic chuck devices are used to secure silicon wafers in vacuum chambers. These electrostatic chuck devices include a chuck plate that electrostatically attracts the object and a metal base plate that contacts the backside of the chuck plate. A coolant flows through an internal flow path formed in the base plate, allowing plasma heat applied to the silicon wafer held to the chuck plate to escape toward the base plate. This achieves uniform surface temperature distribution for the silicon wafer. Furthermore, a thermally conductive gas such as helium is supplied to the gaps between the chuck plate and the silicon wafer, resulting from minute irregularities, to enhance heat transfer efficiency.

[0003] The base plate of the electrostatic chuck described in Patent Documents 1 and 2 includes a disk-shaped main body having a spiral flow path formed in a face plate portion by groove machining using an end mill or the like, and a thin disk-shaped cover joined to the main body by diffusion bonding or the like so as to close the opening of the groove. The flow path in the base plate has openings at both ends on the side surface of the base plate, and a coolant is introduced through one opening, circulates throughout almost the entire area within the base plate, and then is discharged to the outside through the other opening.

[0004] The spiral flow path formed in the main body is formed so that adjacent portions are spaced apart by a predetermined distance in the radial direction, because a bonding margin of at least a predetermined width is required to diffusion bond the lid to the main body with the required strength.

[0005] There are many areas in the base plate where the coolant does not flow due to the joint area, and the spiral flow path makes it difficult to uniformly flow the coolant at the desired flow rate within the base plate, which results in temperature unevenness on the surface of the base plate that is the cooling surface.As a result, it may not be possible to uniformly cool the entire silicon wafer.

[0006] Furthermore, the joint area creates a solid structure, which increases the heat capacity accordingly, making it difficult to lower the temperature of the base plate itself and slowing down the cooling rate.

[0007] In addition, base plates manufactured by diffusion bonding, for example, use aluminum (Al), which limits the size of the base plate due to the required mechanical strength. For the above-mentioned metals or alloys, base materials larger than a certain size are not commercially available, so it is not possible to manufacture larger base plates by machining. This makes it difficult to increase the size of electrostatic chuck devices to accommodate larger substrates. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-113588 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-126900 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention is intended to solve all of the above-mentioned problems at once, and has an object to provide an electrostatic chuck device that can accommodate larger substrates and can significantly improve the cooling capacity of the object to be chucked compared to conventional devices. [Means for solving the problem]

[0010] That is, an electrostatic chuck device according to the present invention is an electrostatic chuck device that attracts an object by electrostatic force, and includes: an attraction plate whose front surface forms an attraction surface that attracts the object; and a base plate having an internal flow path through which a coolant flows, the internal flow path including radial flow paths through which the coolant flows radially from the center of the base plate toward the outer periphery; and a concentrated flow path through which the coolant flows in a concentrated manner from the outer periphery toward the center of the base plate, and the radial flow paths and the concentrated flow path are formed by stacking them within the base plate.

[0011] In this case, the radial flow paths and the concentrated flow path are formed within the base plate, making it easier to form the base plate using, for example, 3D printing or additive manufacturing with metal particles, compared to conventional spiral flow paths. Therefore, the base plate does not need to be composed of two components, a main body and a lid, and diffusion bonded to each other, eliminating the need for a joint. Therefore, the radial flow paths and the concentrated flow path can be formed uniformly throughout the base plate, and the flow path volume can be made larger than conventional. As a result, the amount of refrigerant flowing within the base plate can be increased compared to conventional methods, and the heat capacity of the base plate can be reduced, significantly lowering the cooling temperature.

[0012] Furthermore, with 3D printing and additive manufacturing, metal particles are fused together, making it possible to maintain high mechanical strength even with a high void ratio. Furthermore, by using the above-mentioned manufacturing methods, it is possible to create larger base plates than before, even with high-strength materials that do not have a large base material for cutting, making it possible to accommodate larger substrates.

[0013] Furthermore, the refrigerant is configured to flow from radial flow paths formed on the front side of the base plate to a centralized flow path formed on the back side of the base plate, so that the refrigerant temperature is made uniform by heat exchange between the refrigerants flowing through each radial flow path, thereby reducing temperature unevenness across the entire base plate.

[0014] To prevent the suction plate from being distorted by thermal shock caused by the temperature difference between the base plate and the suction plate, a thermal shock absorbing layer may be provided between the base plate and the suction plate. That is, even if the base plate is cooled to an extremely low temperature by a refrigerant, the thermal shock is not directly transmitted to the suction plate but is absorbed by the thermal shock absorbing layer. Therefore, the cooling temperature can be lowered compared to conventional methods to prevent the suction plate from being distorted.

[0015] In order to facilitate heat exchange between the refrigerant flowing through the radial flow paths and the refrigerant flowing through the concentrated flow path and to keep the temperature of the entire base plate low and uniform, the radial flow paths and the concentrated flow path may be separated into two layers by an internal partition thin plate provided within the base plate.

[0016] In order to be able to strongly cool the central portion of the object adsorbed to the adsorption plate, which is prone to become hot, and to reduce temperature unevenness of the object by circulating the refrigerant between the radial flow paths and the centralized flow path, the internal flow path needs to further include an inlet flow path that extends in the thickness direction of the base plate at the central portion of the base plate and allows the refrigerant to flow into the central portion of the radial flow paths, a connecting flow path that connects the outer periphery of the radial flow paths with the outer periphery of the centralized flow path in the thickness direction, and an outlet flow path that extends in the thickness direction of the base plate outside the inlet pipe and allows the refrigerant to flow out from the central portion of the centralized flow path to the outside of the base plate.

[0017] To prevent condensation from forming on the cooled base plate and to prevent the cooling efficiency from decreasing due to the refrigerant being heated by outside air, a vacuum insulation layer is formed inside the base plate on the back side of the concentrated flow path.

[0018] In order to improve the heat exchange efficiency between the object adsorbed on the adsorption plate and the refrigerant and to achieve a predetermined mechanical strength within the radial flow paths and the concentrated flow path, the radial flow paths and the concentrated flow path may be formed with a fin structure having a large number of fins arranged in a row, which can function not only for heat exchange but also as a support structure within the base plate to obtain mechanical strength.

[0019] In order to more precisely eliminate temperature unevenness in the object adsorbed to the adsorption plate, the device may further include a gas supply mechanism that supplies a thermally conductive gas between the adsorption surface of the adsorption plate and the adsorbed surface of the object, the gas supply mechanism comprising a plurality of gas supply flow paths formed to open onto the adsorption surface of the adsorption plate, a plurality of gas supply regions defined on the adsorption surface and to which the thermally conductive gas is individually supplied by each gas supply flow path, and a plurality of flow rate control devices that individually control the flow rate of the thermally conductive gas supplied to each gas supply region.

[0020] In order to reduce the amount of metal material forming the base plate as much as possible, reduce the heat capacity, make it easier to lower the temperature, and also achieve the mechanical strength required when adsorbing an object of a predetermined size or larger, it is sufficient to form a lattice structure on the back side of the base plate.

[0021] If the lattice structure is a structure formed by topology optimization, it can be made into a shape that satisfies the characteristics required for the base plate.

[0022] More preferably, the lattice structure is determined by topology optimization under the constraints that the base plate has a strength equal to or greater than a predetermined value and a heat capacity equal to or less than a predetermined value, which makes it possible to obtain a lattice structure that satisfies the characteristics required for the base plate.

[0023] To enable the manufacture of a base plate of a size required to adsorb larger objects than conventional ones while enabling the formation of shapes that are difficult to form by machining, such as the fin structure or lattice structure described above, the base plate may be formed by 3D printing or additive manufacturing using metal particles containing titanium (Ti) or alloy particles containing at least nickel (Ni), molybdenum (Mo), and chromium (Cr). In other words, by using 3D printing or additive manufacturing, it is possible to manufacture an electrostatic chuck device that can adsorb very large objects and can be sufficiently cooled using a high-strength metal material that does not have a large-sized base material. [Effects of the Invention]

[0024] As described above, in the electrostatic chuck device according to the present invention, the base plate includes the radial flow channels and the concentrated flow channel. This facilitates fabrication by, for example, 3D printing or additive manufacturing, eliminating the need for a large bonding area for diffusion bonding, as in the past. Therefore, while maintaining mechanical strength, the flow channel volume within the base plate can be increased, allowing for an increased amount of refrigerant to be accommodated, and the heat capacity of the base plate can be reduced. As a result, the temperature of the base plate can be significantly reduced compared to conventional methods. Furthermore, it is possible to fabricate the base plate in a size that can accommodate larger substrates using a material that can maintain high mechanical strength. Furthermore, heat exchange between the refrigerant flowing through the radial flow channels and the concentrated flow channel can homogenize the temperature of the refrigerant, thereby reducing temperature variations in the base plate. Therefore, the object attracted to the attraction plate can be uniformly cooled without the need for a heat equalizer or other component. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic diagram showing the overall configuration of an electrostatic chuck device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view schematically showing the configuration of the electrostatic chuck device according to the embodiment. [Figure 3] FIG. 2 is a schematic perspective view of the base plate of the embodiment, with a portion thereof cut away, as viewed from above. [Figure 4] FIG. 2 is a schematic perspective view of the base plate of the embodiment with a portion cut away, as viewed from below. [Figure 5] FIG. 5 is an enlarged schematic view of a cut end surface in the schematic perspective views of FIGS. 3 and 4. [Figure 6] FIG. 4 is a schematic diagram showing the flow of radial flow channels in the embodiment; [Figure 7] FIG. 3 is a schematic diagram showing the flow of a concentrated flow path in the same embodiment. [Figure 8] FIG. 2 is a schematic diagram showing the configuration of the surface of the suction plate according to the embodiment; [Figure 9] FIG. 4 is a schematic diagram showing the configuration of the back surface of the suction plate of the embodiment. [Figure 10] 9 is a schematic cross-sectional view taken along line AA shown in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0026] An electrostatic chuck device 100 according to one embodiment of the present invention will be described with reference to the accompanying drawings.

[0027] 1 and 2, an electrostatic chuck device 100 according to this embodiment is configured to electrostatically attract a wafer W to be processed in a vacuum chamber C of, for example, a plasma-based semiconductor manufacturing apparatus. Specifically, the electrostatic chuck device 100 includes an attraction plate 1 having an attraction surface on its front side for electrostatically attracting the wafer W, a base plate 2 having a cooling surface for cooling the attraction plate 1, a thermal shock absorbing layer 3 provided between the back side of the attraction plate 1 and the cooling surface of the attraction plate 1, gas supply mechanisms GA, GB, and GC for supplying a thermally conductive gas (backside gas) between the attraction surface of the attraction plate 1 and the non-attraction surface of the wafer W, and a coolant supply mechanism F for supplying a coolant into the base plate 2. The vacuum chamber C is configured to be evacuated by a vacuum pump V1.

[0028] As shown in FIGS. 1 and 2, the suction plate 1 is a circular flat plate made of an insulating material such as ceramic or glass. An internal electrode (not shown) is embedded in the suction plate 1, and a voltage is applied to it from a power supply 11. When a voltage is applied to the internal electrode, a dielectric polarization phenomenon occurs within the suction plate 1, and the front surface of the suction plate 1 becomes the suction surface. The suction plate 1 is, for example, a bipolar type, but is not limited to this and may be a monopolar type. In this specification, the front surface of the suction plate 1 refers to the surface on which the wafer W is suctioned, and the back surface of the suction plate 1 refers to the surface facing the base plate 2.

[0029] The thermal shock absorbing layer 3 is formed of a circular thin plate or film made of a low thermal expansion metal such as Super Invar (registered trademark). The thermal shock absorbing layer 3 may have a thermal expansion coefficient equal to or lower than that of the material constituting the base plate 2 and equal to or higher than that of the material constituting the suction plate 1.

[0030] As shown in FIGS. 1, 2, 3, and 4, the base plate 2 is a circular, flat metal formed body having a hollow structure and a thickness greater than that of the chucking plate 1. In this embodiment, the base plate 2 is formed by 3D printing or additive manufacturing using metal particles containing titanium (Ti). That is, as shown in the schematic longitudinal cross-sectional view of FIG. 2, the base plate 2 includes, in order from the front surface side (the cooling surface), an internal flow path 21 through which a coolant flows, a vacuum insulation layer 22 formed below the internal flow path 21, and a lattice structure 23 provided below the vacuum insulation layer 22, forming a layered structure. In this specification, the front surface of the base plate 2 refers to the side on which the cooling surface for cooling the chucking plate 1 is formed, and the back surface refers to the side opposite the cooling surface. In other words, when configured as an electrostatic chuck device 100, the surface of the chucking plate 1 and the base plate 2 facing the wafer W to be chucking can be referred to as the front surface, and the opposite surface can be referred to as the back surface.

[0031] 1, the internal flow path 21 is connected to a refrigerant supply mechanism F located outside the base plate 2, and is configured to circulate a refrigerant between the base plate 2 and the refrigerant supply mechanism F. The refrigerant supply mechanism F is equipped with, for example, a chiller unit that cools the refrigerant, a supply pump, etc., and controls the temperature so that a refrigerant of, for example, -80°C or below is supplied into the base plate 2.

[0032] Specifically, as shown in Figures 2, 3, and 4, the internal flow path 21 is configured so that the refrigerant flows in and out from the center of the base plate 2 along the axial direction, and so that there are two layers of outward and return paths along the radial direction (face plate direction) of the base plate 2 on the cooling surface side inside the base plate 2. As shown in Figure 2, the refrigerant flows out of the outward path of the internal flow path 21 from the center of the base plate 2 and turns back at the outer periphery to the return path located below. In the return path of the internal flow path 21, the refrigerant flows from the outer periphery of the base plate 2 toward the center.

[0033] The detailed structure of the internal flow path 21 will be described with reference to Figures 3, 4, and 5. Figures 3 and 4 are schematic perspective views in which a portion of the base plate 2 is cut away to reveal the internal structure, and Figure 5 is an enlarged view of the end face of the cutaway portion in Figures 3 and 4. Note that the lattice structure 23 is not shown in Figures 3 and 4. Also, the cross-hatched portion in Figure 5 indicates the lattice structure 23, but this is a simplified representation of the lattice structure 23 and differs from the actual shape.

[0034] The internal flow path 21 extends in the axial direction (thickness direction of the base plate 2) at the center of the base plate 2 and is equipped with an inlet flow path L1 into which the refrigerant flows from the refrigerant supply mechanism F, radial flow paths L2 through which the refrigerant flowing in from the inlet flow path L1 flows from the center of the base plate 2 toward the outer periphery, a concentrated flow path L4 formed below the radial flow paths L2 through which the refrigerant that has passed through the radial flow paths L2 flows from the outer periphery toward the center of the base plate 2, a roughly annular connecting flow path L3 that axially connects the outer peripheries of the radial flow paths L2 and the concentrated flow path L4, and an outlet flow path L5 that extends in the axial direction at the center of the base plate 2 and through which the refrigerant that has passed through the concentrated flow path L4 flows out of the base plate 2.

[0035] 3 to 5, the inflow passage L1 is a passage extending along the central axis of the base plate 2, and the outflow passage L5 is formed as a plurality of small-diameter hollow cylinders passing through a cylindrical partition wall forming the inflow passage L1. The inflow passage L1 and the outflow passage L5 may be realized, for example, as a double-pipe structure. Furthermore, the radial passages L2 and the concentrated passage L4 are formed by stacking them within the base plate 2 and are separated by an internal partition wall thin plate 2P having a generally thin, disc-like shape that extends along the radial direction (face plate direction) of the base plate 2.

[0036] The radial flow paths L2 are configured so that the refrigerant flowing out from the opening of the inlet flow path L1 in the center flows radially toward the connecting flow paths L3 on the outermost periphery, as shown by the arrows in Fig. 6. More specifically, the radial flow paths L2 are configured so that the radial flow is formed by a fin structure (not shown) in which multiple fins are arranged, and heat exchange occurs between the refrigerant and the base plate 2.

[0037] The concentrated flow path L4 is configured so that the refrigerant is concentrated from the connecting flow paths L3 at the outermost periphery toward the opening of the inlet flow path L1 at the center, as shown by the arrows in Fig. 7. More specifically, the concentrated flow path L4 is configured so that a radial flow is formed by a fin structure (not shown) in which multiple fins are arranged, and heat exchange occurs between the refrigerant and the base plate 2.

[0038] 6 and 7 do not indicate the flow lines themselves, but rather indicate the general flow direction. In other words, a radial flow or a concentrated flow does not necessarily mean that the fluid flows linearly along the radial axis of the base plate 2, but the flow lines may be curved or meandering from the center to the outer periphery.

[0039] The fins that form the radial flow paths L2 and the concentrated flow path L4 have, for example, an elliptical blade cross section, and connect between the internal partition wall thin plate 2P and the surface plate of the base plate 2 that forms the cooling surface, or between the internal partition wall thin plate 2P and the partition that forms the vacuum insulation layer 22. In other words, the fin structure itself supports the weight of each component and the refrigerant as a structural body.

[0040] The arrangement and shape of each fin in the fin structure are determined based on the results of FEM analysis and topology optimization. Constraints for optimization include, for example, some or all of the following: the amount of heat exchange in the fin structure, the weight that the fin structure must support, weight restrictions on the base plate 2, and the shape of each streamline that forms the radial flow.

[0041] Because these internal flow paths 21 are formed within the base plate 2, temperature unevenness in the base plate 2 can be reduced compared to, for example, a case in which only the radial flow paths L2 are formed within the base plate 2. That is, the refrigerant flowing through the radial flow paths L2 generates a temperature gradient such that the refrigerant temperature is lowest at the center and highest at the periphery, whereas the concentrated flow path L4 generates a temperature gradient such that the refrigerant temperature is lowest at the periphery and highest at the center. Because the radial flow paths L2 and the concentrated flow path L4 are stacked coaxially and formed only through the internal partition thin plate 2P, heat exchange between the refrigerant flowing through each flow path reduces the temperature gradients in the opposite directions, thereby minimizing deviation from the average temperature throughout the entire flow path. This reduces temperature unevenness in the radial direction of the base plate 2, preventing temperature unevenness on the wafer W due to uneven cooling even without the use of a heat equalizer.

[0042] Next, the vacuum insulation layer 22 and the lattice structure 23 will be described with reference to Figures 2 and 5. The vacuum insulation layer 22 is provided below the concentrated flow path L4, i.e., on the back side of the base plate 2, so as to isolate the concentrated flow path L4 from the outside air. In this way, condensation and the like caused by the refrigerant flowing through the concentrated flow path L4 is prevented, and heat is prevented from leaking to the outside.

[0043] The lattice structure 23 (grid structure) is provided below the vacuum insulation layer 22, and its shape is determined by topology optimization, for example. More specifically, it is a structure determined by topology optimization under the constraints that the base plate 2 has strength equal to or greater than a predetermined value and a heat capacity equal to or less than a predetermined value. Other constraints may also be used. The lattice structure 23 may also be determined by topology optimization using various methods, such as the level set method or the density method. The lattice structure 23 may also be a structure formed by repeating cells, each of which is a basic three-dimensional shape having a hole.

[0044] Finally, the gas supply mechanisms GA, GB, GC and the suction plate 1 will be described in detail with reference to Figures 1, 8, 9 and 10. For ease of understanding, in Figures 8 and 9, the gas circulation holes 12 are depicted larger than their proportion to the suction plate 1, and do not match the size of the gas circulation holes 12 in Figure 10.

[0045] In this embodiment, the suction plate 1 is divided into three zones ZA, ZB, and ZC at 120-degree intervals as shown in Fig. 8, and the supply flow rate of the backside gas is controlled for each of these zones, and each flow rate can be controlled independently. That is, the supply flow rate of the backside gas is controlled for each of the zones ZA, ZB, and ZC by the mass flow controllers provided in the three independent gas supply mechanisms GA, GB, and GC.

[0046] As shown in Fig. 8, gas circulation holes 12 are formed in the suction plate 1, penetrating both sides. The gas circulation holes 12 belonging to each of the zones ZA, ZB, and ZC are connected to one another by gas circulation grooves 13 formed on the back surface of the suction plate 1, as shown in Fig. 9. For example, one of the gas circulation holes 12 in each of the zones ZA, ZB, and ZC located on the inner periphery is connected to a gas supply line, and backside gas is supplied to each of the gas circulation holes by a separate mass flow controller. As shown in Fig. 9, which is a cross-sectional view of line AA in Fig. 8, the base plate 2 is formed with gas connection holes 24 that connect the gas circulation holes 12 in the suction plate 1 to the gas supply lines of the gas supply mechanisms GA, GB, and GC.

[0047] In the electrostatic chuck device 100 of this embodiment configured as described above, the radial flow paths L2 and the concentrated flow paths L4 are formed in the base plate 2 using a fin structure. This makes it easier to form the base plate 2 by, for example, 3D printing or additive manufacturing using metal particles, compared to conventional spiral flow paths. Therefore, the base plate 2 does not need to be composed of two components, a main body and a lid, and diffusion bonded to each other, eliminating the need for a joint. Therefore, the radial flow paths L2 and the concentrated flow paths L4 can be formed uniformly throughout the base plate 2, allowing the coolant to flow uniformly within the base plate 2 and increasing the flow rate.

[0048] Furthermore, the fin structure or lattice structure 23 in the radial flow paths L2 and the concentrated flow path L4 increases the hollow ratio of the base plate 2, thereby reducing the heat capacity of the base plate 2. Therefore, by increasing the amount of refrigerant and reducing the heat capacity, it is possible to lower the cooling temperature of the base plate 2 and improve the cooling rate, even for metal materials with poor thermal conductivity.

[0049] Furthermore, since the radial flow paths L2 and the concentrated flow path L4 make it easier to make the flow follow the design compared to a spiral flow path, it is possible to make it difficult for temperature unevenness to occur in the base plate 2 in the first place.

[0050] Additionally, because the base plate 2 is formed using titanium by 3D printing or additive manufacturing, there is no bonded interface, as is the case with conventional bonding methods, making it more resistant to thermal shock caused by cooling. Furthermore, by thinning the partition wall that forms the cooling surface of the base plate 2, the distance between the suction plate 1 and the internal flow path 21 through which the coolant flows can be reduced. This makes it easier to cool the wafer W attached to the suction plate 1 than in the past. Furthermore, 3D printing and additive manufacturing can be used to manufacture base plates 2 of sizes that are difficult to produce by machining. For example, metals such as titanium, which are difficult to prepare as large base materials, can be selected as materials. Therefore, electrostatic chuck devices 100 of sizes that were previously difficult to achieve can be realized to accommodate larger wafers W.

[0051] Furthermore, even if the heat capacity is reduced or the thickness is reduced, sufficient mechanical strength can be maintained due to the lattice structure 23. In addition, the flow rate of the backside gas supplied between the chucking plate 1 and the wafer W can be divided into multiple zones ZA, ZB, and ZC, and each can be controlled by a mass flow controller (or pressure-type mass flow controller) capable of measuring individual pressures, allowing for precise temperature control to prevent temperature distribution on the wafer W.

[0052] Other embodiments will be described.

[0053] The configuration of the internal flow paths is not limited to that shown in the above-described embodiment. For example, a concentrated flow path may be disposed on the front side of the base plate, and radial flow paths may be formed on the back side of the base plate. Specifically, the refrigerant may flow into the concentrated flow path from the outer peripheral surface of the base plate, pass through the concentrated flow path, and then flow to the center of the radial flow paths via connecting flow paths formed in the center, and then flow out again from the outer peripheral surface to the outside of the base plate. In other words, the radial flow paths and the concentrated flow path may be formed in a stacked manner within the base plate.

[0054] The metal forming the base plate is not limited to titanium, and the base plate may be formed by 3D printing or additive manufacturing using alloy particles containing at least nickel (Ni), molybdenum (Mo), and chromium (Cr), such as Inconel (registered trademark).

[0055] The electrostatic chuck device according to the present invention is not limited to applications such as plasma processing, but may also be used in other semiconductor manufacturing processes performed in chambers.

[0056] The position where the lattice structure is provided is not limited to the position in the above-described embodiment. For example, the lattice structure may be formed by forming a gap in the base plate to reduce heat capacity. The internal partition wall thin plate separating the radial flow paths and the concentrated flow path may have a hollow portion, and the lattice structure may be formed in that hollow portion.

[0057] The thermally conductive gas supplied to the gap between the suction plate and the object may be a noble gas such as helium, but other gases may also be used. The number of zones into which the thermally conductive gas is supplied may be two, four, or more. The greater the number of zones, the more precise the temperature control of the object, such as a wafer, can be achieved.

[0058] If the suction plate has sufficient resistance to thermal shock due to its material, shape, etc., the suction plate may be directly mounted on the cooling surface of the base plate without providing a thermal shock absorbing layer between the base plate and the suction plate.

[0059] In addition, various modifications of the embodiments and combinations of parts of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0060] 100: Electrostatic chuck device 1: Adsorption plate 11: Power supply 12: Gas flow hole 13: Gas flow groove 2: Base plate 2P: Internal bulkhead thin plate 21: Internal flow path L1: Inlet flow path L2: Radial flow path L3: Connecting channel L4: Concentrated flow path L5: Outlet channel 22: Vacuum insulation layer 23: Lattice structure 24: Gas connection hole 3: Thermal shock mitigation layer C: Vacuum chamber F: Refrigerant supply mechanism GA: Gas supply mechanism GB: Gas supply mechanism GC: Gas supply mechanism V1: Vacuum pump W: Wafer ZA: Zone ZB: Zone ZC: Zone

Claims

1. An electrostatic chuck device that attracts an object by electrostatic force, an adsorption plate having a surface that adsorbs the object; a base plate that is an additively manufactured object and has an internal flow path through which a coolant flows; a thermal shock absorbing layer provided between the back surface side of the suction plate and the front surface side of the base plate, the thermal shock absorbing layer suppressing heat transfer between the suction plate and the base plate to absorb thermal shock; The internal flow path is a radial flow path through which a coolant flows radially from a central portion of the base plate toward an outer periphery thereof; a concentrated flow path through which the coolant flows in a concentrated manner from the outer periphery of the base plate toward the center thereof, An electrostatic chuck device in which the radial flow paths and the concentrated flow path are formed in a stack within the base plate.

2. 2. The electrostatic chuck device according to claim 1, wherein the radial flow paths and the concentrated flow path are separated into two layers by an internal partition wall thin plate provided within the base plate.

3. The internal flow path is an inlet flow path extending in a thickness direction of the base plate at a central portion of the base plate and allowing a refrigerant to flow into the central portion of the radial flow paths; a connecting flow path that connects an outer periphery of the radial flow path and an outer periphery of the concentrated flow path in a thickness direction; 3. The electrostatic chuck device according to claim 1, further comprising: an outlet flow path extending in a thickness direction of the base plate outside the inlet flow path and allowing the coolant to flow out of the base plate from a central portion of the concentrated flow path.

4. 4. The electrostatic chuck device according to claim 1, wherein a vacuum heat insulating layer is formed inside the base plate on a rear side of the concentrated flow path.

5. 5. The electrostatic chuck device according to claim 1, wherein the radial flow paths and the concentrated flow path are formed by a fin structure in which a number of fins are arranged.

6. a gas supply mechanism for supplying a thermally conductive gas between the suction surface of the suction plate and the suction target surface of the object; the gas supply mechanism has a plurality of gas supply channels formed to open on the suction surface of the suction plate; a plurality of gas supply regions formed on the adsorption surface, each of which is individually supplied with a thermally conductive gas by a corresponding gas supply passage; 6. The electrostatic chuck device according to claim 1, further comprising a plurality of flow rate control devices that individually control the flow rates of the thermally conductive gases supplied to the respective gas supply regions.

7. 7. The electrostatic chuck device according to claim 1, wherein a lattice structure is formed on the rear surface of the base plate.

8. 8. The electrostatic chuck device according to claim 7, wherein the lattice structure is a structure formed by topology optimization.

9. 9. The electrostatic chuck device according to claim 8, wherein the lattice structure is determined by topology optimization under constraints that the base plate has a strength equal to or greater than a predetermined value and a heat capacity equal to or less than a predetermined value.

10. 10. The electrostatic chuck device according to claim 1, wherein the base plate is formed by 3D printing or additive manufacturing using metal particles containing titanium (Ti) or alloy particles containing at least nickel (Ni), molybdenum (Mo), and chromium (Cr).

11. An electrostatic chuck device that attracts an object by electrostatic force, an adsorption plate having a surface that adsorbs the object; a base plate having an internal flow path through which a coolant flows; The internal flow path is a radial flow path through which a coolant flows radially from a central portion of the base plate toward an outer periphery thereof; a concentrated flow path through which the coolant flows in a concentrated manner from the outer periphery of the base plate toward the center thereof, the radial flow paths and the concentrated flow paths are formed in a stacked manner within the base plate, An electrostatic chuck device in which a vacuum heat insulating layer is formed inside the base plate on a rear side of the concentrated flow path.

12. An electrostatic chuck device that attracts an object by electrostatic force, an adsorption plate having a surface that adsorbs the object; a base plate having an internal flow path through which a coolant flows; The internal flow path is a radial flow path through which a coolant flows radially from a central portion of the base plate toward an outer periphery thereof; a concentrated flow path through which the coolant flows in a concentrated manner from the outer periphery of the base plate toward the center thereof, the radial flow paths and the concentrated flow paths are formed in a stacked manner within the base plate, The electrostatic chuck device has a fin structure in which the radial flow paths and the concentrated flow path are formed by arranging a large number of fins.

13. An electrostatic chuck device that attracts an object by electrostatic force, an adsorption plate having a surface that adsorbs the object; a base plate having an internal flow path through which a coolant flows; The internal flow path is a radial flow path through which a coolant flows radially from a central portion of the base plate toward an outer periphery thereof; a concentrated flow path through which the coolant flows in a concentrated manner from the outer periphery of the base plate toward the center thereof, the radial flow paths and the concentrated flow paths are formed in a stacked manner within the base plate, An electrostatic chuck device in which a lattice structure is formed on the back surface of the base plate.

14. An electrostatic chuck device that attracts an object by electrostatic force, an adsorption plate having a surface that adsorbs the object; a base plate having an internal flow path through which a coolant flows; The internal flow path is a radial flow path through which a coolant flows radially from a central portion of the base plate toward an outer periphery thereof; a concentrated flow path through which the coolant flows in a concentrated manner from the outer periphery of the base plate toward the center thereof, the radial flow paths and the concentrated flow paths are formed in a stacked manner within the base plate, The electrostatic chuck device is an electrostatic chuck device in which the base plate is formed by 3D printing or additive manufacturing using metal particles containing titanium (Ti) or alloy particles containing at least nickel (Ni), molybdenum (Mo), and chromium (Cr).

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