Wafer holder and method for using wafer holder

Abstract

To provide a wafer holder capable of quickly cooling a vacuum-attached wafer.SOLUTION: A wafer holder includes a disk-shaped base having an upper surface on which a wafer is placed, a vacuum path for adsorbing the wafer to the upper surface, and a gas flow path for flowing a gas refrigerant for cooling the wafer. The gas flow path includes a flow path groove opening to the upper surface, a gas inlet path disposed inside the base and leading to a first end of the flow path groove, and a gas exhaust path disposed inside the base and leading to a second end of the flow path groove.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] SUMMARY The present disclosure relates to a wafer holder and a method of using the wafer holder. [Background technology]

[0002] Patent Document 1 discloses a wafer holder for a prober. A prober is an inspection device that measures the electrical performance of each chip before cutting a semiconductor wafer on which multiple circuits are formed into individual chips. The wafer holder disclosed in Patent Document 1 includes a base that is a metal disk. This base includes an upper surface on which the wafer is placed and a vacuum path that adsorbs the wafer to the upper surface.

[0003] In the prober, the wafer is heated or cooled, and then a probe card equipped with multiple electrode pins is pressed against the semiconductor made up of the wafer to pass a current through the semiconductor, which heats up. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-149727 A Summary of the Invention [Problem to be solved by the invention]

[0005] With the recent increase in demand for semiconductors, there is a demand for improving semiconductor productivity. For example, if the temperature of semiconductors that have generated heat during the inspection process can be quickly cooled, the time required for the inspection process can be shortened, thereby improving semiconductor productivity.

[0006] An object of the present disclosure is to provide a wafer holder that is capable of quickly cooling a vacuum-attached wafer, and a method of using the wafer holder. [Means for solving the problem]

[0007] The wafer holder of the present disclosure comprises a disk-shaped base having an upper surface on which a wafer is placed, a vacuum path for adsorbing the wafer to the upper surface, and a gas flow path for flowing a gas coolant for cooling the wafer. The gas flow path comprises a flow groove opening on the upper surface, a gas inlet path disposed inside the base and connected to a first end of the flow groove, and a gas outlet path disposed inside the base and connected to a second end of the flow groove. Effect of the Invention

[0008] The wafer holder of the present disclosure is capable of quickly cooling a wafer held by vacuum chuck. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of the wafer holder described in the first embodiment. [Diagram 2] FIG. 2 is a schematic top view of the base of the wafer holder according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III of FIG. [Figure 4] FIG. 4 is a schematic top view of the base of the wafer holder according to the second embodiment. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a wafer holder according to a modified example. [Figure 6] FIG. 6 is a graph showing the test results of the test examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described.

[0011] <1> A wafer holder according to an embodiment includes a disk-shaped base having an upper surface on which a wafer is placed, a vacuum path for adsorbing the wafer to the upper surface, and a gas flow path for flowing a gas coolant for cooling the wafer. The gas flow path includes a flow groove opening on the upper surface, a gas inlet path disposed inside the base and connected to a first end of the flow groove, and a gas outlet path disposed inside the base and connected to a second end of the flow groove.

[0012] When using a wafer holder having the above configuration, a suction device that sucks gas from the gas exhaust path is connected to the gas exhaust path with a wafer placed on the upper surface of the base. By sucking gas from the gas exhaust path, the gas flow path becomes negative pressure. This negative pressure causes the gas coolant to be sucked from the gas inlet path on the opposite side of the gas exhaust path, and the gas coolant flows from the gas inlet path through the flow path groove toward the gas exhaust path. If the gas flow path is negative pressure, the gas coolant can flow through the gas flow path without impeding the vacuum adsorption of the wafer by the vacuum path. If the gas coolant is pumped through the gas inlet path, the inside of the gas flow path becomes positive pressure. Since the flow path groove in the gas flow path opens to the upper surface of the base, the positive pressure gas coolant reduces the degree of vacuum between the upper surface and the wafer, making it impossible to vacuum adsorb the wafer to the upper surface, or causing stress to act on the wafer, which may damage the wafer.

[0013] The gas coolant flowing through the gas flow passage comes into direct contact with the underside of the wafer, thereby quickly cooling the wafer. The wafer holder having the above-described configuration can shorten the wafer inspection time, enabling inspection of many wafers in a short period of time.

[0014] <2> the above <1> The wafer holder described in the above may further include a coolant passage disposed inside the base for circulating a coolant for cooling the base.

[0015] The coolant circulated through the coolant flow passage may be a liquid coolant or a gas coolant. The coolant flow passage rapidly cools the substrate. Cooling the substrate rapidly cools the wafer.

[0016] <3> the above <1> or <2> The wafer holder described in may include a heater disposed inside the base or on the lower surface of the base.

[0017] The heater heats the base, thereby heating the wafer placed on the top surface of the base, so that the electrical performance of the heated wafer can be inspected in the wafer inspection process.

[0018] <4> the above <1> from <3> In the wafer support table described in any one of the above, the gas flow path may be a first gas flow path that cools the wafer over an entire surface, and the flow path groove in the first gas flow path may be formed over the entire surface of the upper surface.

[0019] The first gas flow passage can rapidly cool the entire surface of the wafer placed on the upper surface.

[0020] <5> the above <4> In the wafer holder described in the above, the flow channel may be composed of a plurality of C-shaped grooves arranged concentrically on the upper surface.

[0021] The multiple concentrically arranged C-grooves allow the entire surface of the wafer to be cooled uniformly.

[0022] <6> the above <1> from <3> In the wafer support table described in any one of the above, the gas flow path may be a second gas flow path that partially cools the wafer, and the flow path groove in the second gas flow path may be formed in a portion of the upper surface.

[0023] The second gas flow path can locally cool the wafer placed on the upper surface. If the flow path groove of the second gas flow path is disposed in a heat generating portion of the wafer that is particularly likely to become hot, the heat generating portion can be rapidly cooled.

[0024] <7> the above <6> In the wafer holder described in the above, the base may include a plurality of heating zones when viewed from above, and the flow channel may be disposed in each of the plurality of heating zones.

[0025] According to the above configuration, the portions of the wafer corresponding to each heating zone can be cooled individually.

[0026] <8> the above <1> from <7> In the wafer holder described in any one of the above, the gas inlet path and the gas outlet path may be open to a side surface of the base.

[0027] If the gas inlet passage is open to the side surface of the base, it is easy to connect a pipe extending from a storage tank that stores a gas refrigerant to the gas inlet passage, and if the gas exhaust passage is open to the side surface of the base, it is easy to connect a pipe extending from a suction device that sucks gas from the gas exhaust passage to the gas exhaust passage.

[0028] <9> the above <1> from <7> In the wafer holder described in any one of the above, the gas inlet path and the gas outlet path may be open to a lower surface of the base.

[0029] The gas inlet passage and the gas exhaust passage that open to the lower surface of the base extend downward. The gas inlet passage and the gas exhaust passage that extend downward can be easily formed so as to avoid the vacuum path formed in the base.

[0030] <10> The method of using the wafer holder of the present disclosure is as described above. <1> from <9> By using the wafer holder according to any one of the above, gas is sucked from the gas exhaust path to create a negative pressure inside the gas flow path, whereby the gas coolant is introduced from the gas inlet path into the flow path groove.

[0031] According to the above-described method of using the wafer holder, the wafer can be directly cooled by the gas coolant while being vacuum-adsorbed.

[0032] <11> the above <10> In the method of using the wafer holder described in , the gas may be sucked through the gas exhaust path so that a product A of a temperature difference ΔT and a cooling capacity C is 10 or more. The temperature difference ΔT is a value obtained by subtracting a temperature of the gas coolant introduced into the gas introduction path from a set temperature of the wafer. The cooling capacity C is a value obtained by dividing a flow rate of the gas coolant in the flow channel by an opening area of ​​the flow channel on the upper surface. The unit of temperature is Celsius, the unit of the flow rate is liters / minute, and the unit of the opening area is square millimeters.

[0033] During wafer inspection, the wafer may be heated to a preset temperature. This preset temperature is the wafer set temperature. The opening area of ​​the flow channel on the upper surface may be considered to be equal to the area where the gas refrigerant flowing through the flow channel comes into contact with the wafer.

[0034] The cooling effect of the gas flow path on the wafer is affected by several factors, such as the temperature of the gas coolant, the flow rate of the gas coolant, and the opening area of ​​the flow groove of the gas flow path. For example, even if the temperature of the gas coolant is low, if the gas flow rate is low or the opening area of ​​the flow groove is too large, it is difficult to obtain a sufficient cooling effect per unit area. If the product A is 10 or more, a desired cooling effect can be obtained.

[0035] <12> The semiconductor processing apparatus of the present disclosure includes the above <1> from <9> and a suction device that sucks gas from the gas exhaust path.

[0036] The semiconductor processing apparatus can directly cool the wafer by a gas coolant while vacuum-adsorbing the wafer.

[0037] <13> the above <12> The semiconductor processing apparatus described in the above may further include a control device that controls the suction device, and the control device may control the suction device so that a product A of a temperature difference ΔT and a cooling capacity C is 10 or more. The temperature difference ΔT is a value obtained by subtracting the temperature of the gas coolant introduced into the gas inlet path from a set temperature of the wafer. The cooling capacity C is a value obtained by dividing the flow rate of the gas coolant in the flow channel by the opening area of ​​the flow channel on the upper surface. The unit of temperature is Celsius, the unit of the flow rate is liters / minute, and the unit of the opening area is square millimeters.

[0038] the above <13> In the above configuration, the wafer temperature that is preset during wafer inspection is the wafer set temperature. <13> In the configuration of (a), the opening area of ​​the flow channel on the upper surface can be considered to be equal to the area where the gas refrigerant flowing through the flow channel comes into contact with the wafer.

[0039] The cooling effect of the gas flow path on the wafer is affected by several factors, such as the temperature of the gas coolant, the flow rate of the gas coolant, and the opening area of ​​the flow groove of the gas flow path. For example, even if the temperature of the gas coolant is low, if the gas flow rate is low or the opening area of ​​the flow groove is too large, it is difficult to obtain a sufficient cooling effect per unit area. If the product A is 10 or more, a desired cooling effect can be obtained.

[0040] [Details of the embodiment of the present disclosure] In the following embodiments, a semiconductor processing apparatus and a wafer holder used in a wafer prober will be described with reference to the drawings. A wafer prober is an inspection device that measures the electrical performance of each chip while controlling a wafer at a predetermined temperature before cutting a semiconductor wafer on which circuits are formed into individual chips. The bold arrows in Figs. 2 and 4 indicate the direction of gas flow. The same reference numerals in the figures indicate the same or equivalent parts. The size of the members shown in each drawing is expressed for the purpose of clarifying the description and does not necessarily represent the actual dimensions. Note that the present invention is not limited to these examples, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0041] <Embodiment 1> Semiconductor processing apparatus 100 shown in FIG. 1 includes wafer holder 1, suction device 8 (FIG. 2), and control device 7 (FIG. 2). Wafer holder 1 includes base 2, support 20, heater 21, and support structure 3. Base 2 has upper surface 2U on which wafer 10 is placed, and lower surface 2D opposite upper surface 2U. Support structure 3 supports base 2 from below. FIG. 1 shows a schematic cross section of wafer holder 1 cut along a plane along the thickness direction of base 2. The thickness direction of base 2 is perpendicular to upper surface 2U of base 2, and is the direction from upper surface 2U to lower surface 2D. Each component will be described in detail below.

[0042] ≪Base≫ The base 2 is a member through which a coolant for cooling the wafer 10 flows. The base 2 in this example also functions as a chuck top for adsorbing the wafer 10. The base 2 is provided with a vacuum path 4, a coolant flow path 5, and a gas flow path 6. These paths will be described later in separate sections.

[0043] The overall shape of the base 2 is a shape that matches the shape of the wafer 10, and is usually configured in a disk shape. The diameter of the top surface 2U of the base 2 is long enough to leave some space around the wafer 10 when it is placed on it. The diameter of the top surface 2U is designed to match the size of the wafer 10 to be placed on the top surface 2U. There are various standards for the size of the wafer 10, ranging from 2 inches (about 50 mm) to 12 inches (about 300 mm) in diameter, with 18 inches (about 450 mm) also being envisioned in the future. Currently, the size of the base 2 that is mainly used industrially is a diameter of the top surface 2U of 100 mm or more and 400 mm or less.

[0044] The thickness of the base 2 is, for example, 15 mm or more and 30 mm or less. If the thickness of the base 2 is 15 mm or more, the rigidity of the base 2 is easily ensured, and the degree of freedom in designing the vacuum path 4, the refrigerant flow path 5, and the gas flow path 6 described later is high. If the thickness of the base 2 is 30 mm or less, the heat capacity of the base 2 is likely to be small. Therefore, the efficiency and responsiveness of heating by the heater and cooling by the refrigerant described later are likely to be high. The thickness of the base 2 may further be 15 mm or more and 20 mm or less, and particularly 16 mm or more and 18 mm or less.

[0045] The base 2 can be made of a metal, nonmetal, or a composite of metal and nonmetal, which have excellent thermal conductivity. The higher the thermal conductivity of the material of the base 2, the better. The metal can be, for example, copper, copper alloy, silver, silver alloy, aluminum, or aluminum alloy. In particular, copper or copper alloy, which have excellent thermal conductivity, is preferable. The nonmetal can be, for example, silicon or ceramics. The ceramic can be, for example, aluminum nitride or silicon carbide. The composite can be, for example, a composite of silicon and silicon carbide, a composite of aluminum and silicon carbide, or a composite of aluminum, silicon, and silicon carbide. The material of the base 2 in this example is oxygen-free copper.

[0046] The thermal conductivity of the material constituting the substrate 2 is, for example, 100 W / m·K or more. The thermal conductivity may further be 200 W / m·K or more, 300 W / m·K or more, and particularly 400 W / m·K or more. The thermal conductivity of aluminum is approximately 230 W / m·K, that of copper is approximately 400 W / m·K, and that of silver is approximately 420 W / m·K. The thermal conductivity of silicon carbide is approximately 200 W / m·K, and that of aluminum nitride is approximately 150 W / m·K.

[0047] The base 2 may be subjected to a surface treatment. The surface treatment is, for example, plating. Specific examples of plating are Ni (nickel) plating or Ni-P (phosphorus) plating. The plating method is, for example, electrolytic plating or electroless plating. The surface treatment in this example is Ni-P plating by electroless plating. When copper containing oxygen-free copper is used as the base 2, it is preferable to perform Ni plating or Ni-P plating. Since copper is likely to diffuse into silicon, which is a constituent material of the wafer 10, the diffusion can be suppressed by performing Ni plating or Ni-P plating. As a result, the reliability of the device obtained from the wafer 10 can be ensured. The area where the surface treatment is performed includes the upper surface 2U of the base 2, which is the upper surface of the wafer 10.

[0048] ≪Support≫ The support 20 is a member for suppressing the occurrence of warping of the base 2 due to heat during inspection of the wafer 10. The support 20 may be provided as necessary and is not an essential member. In the absence of the support 20, the leg member 30 described below supports the base 2. If the support 20 is provided, the wafer holder 1 can be made to be less likely to deform due to the force applied from the upper surface 2U. In this example, the support 20 is in close contact with the lower surface 2D of the base 2. The base 2 and the support 20 can be brought into close contact with each other by fastening screws or by vacuum suction. The vacuum suction is performed, for example, by forming a vacuum flow path on the upper surface of the support 20. By using vacuum suction, elements such as fastening screws are not required, the base 2 can be easily heated uniformly, and the flatness of the upper surface 2U can be easily maintained. By bringing the base 2 and the support 20 into close contact with each other, the rigidity of the entire wafer holder 1 can be increased. The overall shape of the support 20 is a shape that matches the shape of the base 2, and in this example, it is a disk shape. The material of the support 20 is, for example, ceramics or a composite material of ceramics and metal. The ceramics is, for example, alumina, mullite alumina, mullite, cordierite, steatite, silicon nitride, or silicon carbide. Since ceramics have high rigidity, if the support 20 is made of ceramics, it is easy to suppress warping of the base 2.

[0049] <Heater> The heater 21 is a unit for heating the base 2, thereby heating the wafer 10 placed on the upper surface 2U of the base 2 to a predetermined temperature. In this example, the heater 21 is disposed on the lower surface of the support 20. Unlike this example, the heater 21 may be disposed inside the base 2. The heater 21 includes, for example, a disk-shaped heating element. The heating element is, for example, a resistance heating element.

[0050] The heating element of the heater 21 in this example includes a plurality of independent heating elements. Each heating element partially heats the base 2. A plurality of heating zones 2A, which are independent of each other when viewed from above, are formed on the base 2 by each of the plurality of heating elements which are independent of each other. The heating zones 2A are virtual regions. In FIG. 2, the boundaries of each heating zone 2A are indicated by two-dot chain lines.

[0051] The number of heating zones 2A in this example is eight. Specifically, the base 2 in this example includes four sector-shaped heating zones 2A arranged toward the center of the base 2, and four band-shaped heating zones 2A arranged toward the outer periphery of the base 2. The four sector-shaped heating zones 2A are heating zones 2A obtained by dividing a circular central region having a radius that is half the radius of the base 2 into four equal parts in the circumferential direction. The four band-shaped heating zones 2A are heating zones 2A obtained by dividing an annular outer periphery region excluding the central region into four equal parts in the circumferential direction.

[0052] <Vacuum route> The base 2 is provided with a vacuum path 4 for vacuum-adhering the wafer 10 to the upper surface 2U. The vacuum path 4 sucks air from the vicinity of the upper surface 2U and adsorbs the wafer 10 onto the upper surface 2U without any gaps. By adsorbing the wafer 10 onto the upper surface 2U, the wafer 10 can be heated or cooled evenly.

[0053] As shown in FIG. 1 and FIG. 2, the vacuum path 4 includes a horizontal hole 4h, a vertical hole 4v, and an annular groove 4r. The horizontal hole 4h is a hole extending along the upper surface 2U and is disposed inside the base body 2. The horizontal hole 4h has a first end disposed inside the base body 2 and a second end disposed on the side surface 2C of the base body 2. The first end is a closed end. The second end is an open end. A vacuum pump is connected to the open end by a joint or hose (not shown). The vertical hole 4v is connected to the first end of the horizontal hole 4h. The vertical hole 4v is a short hole connecting the horizontal hole 4h and the annular groove 4r. The vertical hole 4v extends in the thickness direction of the base body 2. The annular groove 4r is a plurality of annular grooves concentrically provided on the upper surface 2U as shown in FIG. 2. In this example, the horizontal hole 4h is a linear hole extending from the side surface 2C along the diameter of the base body 2.

[0054] By operating the vacuum pump connected to the horizontal hole 4h, the inside of the vacuum path 4 becomes negative pressure. As a result, air near the upper surface 2U is sucked through the annular groove 4r, flows from the vertical hole 4v to the horizontal hole 4h, and is exhausted from the side surface 2C of the base 2. As a result, the wafer 10 placed on the upper surface 2U is vacuum-adsorbed to the upper surface 2U. The warp of the vacuum-adsorbed wafer 10 is corrected, and the wafer 10 is in approximate surface contact with the upper surface 2U.

[0055] <Refrigerant flow path> The coolant flow path 5 shown in Fig. 1 is disposed inside the base 2. A coolant is circulated through the coolant flow path 5. The coolant may be a gas coolant or a liquid coolant. By circulating the coolant through the coolant flow path 5, the entire base 2 is rapidly cooled. The coolant flow path 5 is not essential.

[0056] For example, when the base 2 is viewed from above, the refrigerant flow path 5 is formed so as to spiral inside the base 2. FIG. 1 shows multiple cross sections of the spiral refrigerant flow path 5. The refrigerant flows into the refrigerant flow path 5 from the inlet, makes a circuit around the refrigerant flow path 5, and is discharged from the outlet of the refrigerant flow path 5. In this example, the number of refrigerant flow paths 5 is one, but there may be multiple refrigerant flow paths 5. The multiple refrigerant flow paths 5 may be arranged on the same plane, or each of the multiple refrigerant flow paths 5 may be arranged on a different plane.

[0057] <Gas flow path> 2 and 3, the base 2 of this example further includes a gas flow path 6. The gas flow path 6 is a path through which a gas coolant that cools the wafer 10 passes. The gas flow path 6 is independent of the coolant flow path 5. The gas flow path 6 of this example is a first gas flow path 61 that cools the entire surface of the wafer 10. The first gas flow path 61 includes a flow path groove 66 formed on the upper surface 2U of the base 2, and a gas inlet path 65 and a gas outlet path 67 that are disposed inside the base 2.

[0058] The flow channel 66 formed in the upper surface 2U opens to the upper surface 2U. Therefore, the gas refrigerant that flows from the gas introduction path 65 into the flow channel 66 directly contacts the wafer 10 placed on the upper surface 2U and cools the wafer 10.

[0059] The flow channel groove 66 in this example is composed of four independent grooves that are independent from each other on the upper surface 2U. Each of the four independent grooves is connected to the gas inlet passage 65 and the gas outlet passage 67. The number of independent grooves is not particularly limited. The number of independent grooves in this example is four. The shape of each independent groove in this example when viewed from above is a C-shaped groove 66C having a C-shape. The multiple C-shaped grooves 66C are arranged concentrically. In this example, the two C-shaped grooves 66C closer to the center of the base 2 are arranged between the second annular groove 4r and the third annular groove 4r as viewed from the center of the base 2. In addition, the two C-shaped grooves 66C closer to the outer periphery of the base 2 are arranged between the third annular groove 4r and the fourth annular groove 4r as viewed from the center of the base 2.

[0060] Flow path groove 66 consisting of four C-shaped grooves 66C is formed over the entire surface of upper surface 2U. In this example, "a state in which flow path grooves 66 are formed over the entire surface of upper surface 2U" means a state in which any of C-shaped grooves 66C is disposed in all heating zones 2A. The gas refrigerant flowing through flow path grooves 66 formed over the entire surface of upper surface 2U can quickly cool the entire surface of wafer 10 placed on upper surface 2U.

[0061] The shape of the flow cross section of the flow channel groove 66 is not particularly limited. The flow cross section of the flow channel groove 66 referred to here means the flow cross section of each independent groove constituting the flow channel groove 66. The flow cross section is a space surrounded by an inner peripheral surface of the flow channel groove 66 cut by a plane perpendicular to the direction in which the flow channel groove 66 extends and an extension surface of the upper surface 2U extended to the opening of the flow channel groove 66. The shape of the flow cross section of the flow channel groove 66 is, for example, a shape having a constant width from the opening to the bottom, such as a rectangular shape. The shape of the flow cross section of the flow channel groove 66 may be a shape in which the opening is wider than the bottom, such as an inverted trapezoid or V-shape.

[0062] The width of the opening of the flow channel 66 is, for example, 0.3 mm (millimeters) or more and 3.0 mm or less. The width of the opening of the flow channel 66 here refers to the width of the opening of each of the independent grooves that make up the flow channel 66. If the width of the flow channel 66 is 0.3 mm or more, a sufficient area can be secured for the gas refrigerant flowing through the flow channel 66 to come into contact with the wafer 10. If the width of the flow channel is 3.0 mm or less, the gas refrigerant can easily flow smoothly along the flow channel 66. The width of the flow channel 66 may be, for example, 0.5 mm or more and 1.5 mm or less, or 0.8 mm or more and 1.2 mm or less.

[0063] The depth of the flow channel 66 is, for example, 0.3 mm (millimeters) or more and 1.5 mm or less. The depth of the flow channel 66 here refers to the depth of each independent groove constituting the flow channel 66. The depth of the flow channel 66 is the length from an extension surface extending the upper surface 2U to the opening of the flow channel 66 to the deepest part of the flow channel 66. If the depth of the flow channel 66 is 0.3 mm or more, a sufficient amount of gas refrigerant can flow in the flow channel 66, and the wafer 10 can be effectively cooled. If the depth of the flow channel 66 is 1.5 mm or less, the amount of gas refrigerant discharged without contacting the wafer 10 can be reduced, and the wafer 10 can be effectively cooled. The depth of the flow channel 66 may be 0.5 mm or more and 1.3 mm or less, or 0.8 mm or more and 1.0 mm or less.

[0064] The cross-sectional area of ​​the flow channel 66 is, for example, 0.09 mm 2 (square millimeters) over 4.5mm 2The cross-sectional area of ​​the flow passage groove 66 here refers to the cross-sectional area of ​​each independent groove that constitutes the flow passage groove 66. 2 If the cross-sectional area of ​​the flow channel 66 is 4.5 mm or more, a sufficient amount of gas coolant can be made to flow through the flow channel 66, and the wafer 10 can be effectively cooled. 2 If the cross-sectional area of ​​the flow channel 66 is 0.5 mm or less, the amount of gas coolant discharged without contacting the wafer 10 can be reduced, and the wafer 10 can be effectively cooled. 2 More than 2.0mm 2 Less than 0.8mm is fine. 2 More than 1.5mm 2 The following is also fine.

[0065] The gas introduction passage 65 of this example includes a horizontal hole 65h extending from the side surface 2C of the base 2 toward the center of the base 2, and a plurality of vertical holes 65v extending from the middle of the horizontal hole 65h toward the upper surface 2U of the base 2. The horizontal hole 65h is formed along a plane parallel to the upper surface 2U. Each vertical hole 65v is connected to a first end 66A of a different C-shaped groove 66C. The first end 66A is an end in a direction along the length of the C-shaped groove 66C.

[0066] The gas exhaust passage 67 of this example has a similar configuration to the gas introduction passage 65. That is, the gas exhaust passage 67 includes a horizontal hole 67h extending from the side surface 2C of the base 2 toward the center of the base 2, and a plurality of vertical holes 67v extending from the middle of the horizontal hole 67h toward the upper surface 2U of the base 2. Each vertical hole 67v is connected to a second end 66B of a different C-shaped groove 66C. The second end 66B is an end opposite to the first end 66A.

[0067] ≪Suction device 8≫ The semiconductor processing apparatus 100 of this embodiment includes a suction device 8 connected to a gas exhaust path 67. The suction device 8 sucks gas from the gas exhaust path 67. By sucking gas from the gas exhaust path 67 with the wafer 10 placed on the upper surface 2U, the first gas flow path 61 becomes negative pressure. Due to this negative pressure, the gas refrigerant is sucked from the gas inlet path 65 on the opposite side of the gas exhaust path 67, and the gas refrigerant flows from the gas inlet path 65 through the flow path groove 66 toward the gas exhaust path 67. If the first gas flow path 61 is negative pressure, the gas refrigerant can flow through the first gas flow path 61 without impeding the vacuum adsorption of the wafer 10 by the vacuum path 4.

[0068] The suction device 8 may be, for example, a vacuum pump or an ejector. In this embodiment, the suction device 8 is an ejector. Since the ejector has a simple structure, it does not take up much space compared to a vacuum pump. In addition, the ejector has a simple structure and is easy to maintain. The suction device 8 is controlled by the control device 7.

[0069] The gas coolant is not particularly limited as long as it does not chemically alter the wafer 10. For example, the gas coolant may be air or an inert gas. The inert gas is, for example, nitrogen or helium. The temperature of the gas coolant is adjusted by a temperature adjustment device (not shown). The temperature adjustment device includes, for example, a cooling device for cooling the gas coolant and a storage tank for storing the temperature-adjusted gas coolant. When the first gas flow path 61 becomes negative pressure, the gas coolant is sucked out of the storage tank and introduced into the first gas flow path 61. The gas coolant is not pumped from the storage tank to the first gas flow path 61. That is, the temperature adjustment device of this example does not include a gas coolant pumping device.

[0070] Control Device The control device 7 controls the suction device 8 to adjust the flow rate of the gas refrigerant in the gas flow path 6. That is, the cooling state of the wafer 10 by the gas refrigerant is controlled by the control device 7. The control device 7 may control components other than the suction device 8 in addition to the suction device 8.

[0071] Each process by the control device 7 is realized by a processing circuit including at least one processor. The processing circuit may be composed of an integrated circuit in which at least one memory, various analog circuits, and various digital circuits are combined in addition to the at least one processor. The at least one memory stores a program (instruction) for causing the at least one processor to execute each of the above processes. The at least one processor may execute each of the above processes according to the program read from the at least one memory, or may execute each of the above processes according to a logic circuit designed in advance to execute each of the above processes. The processor may be, for example, a CPU or a GPU, or any of various other processors suitable for computer control. Note that the physically separated processors may cooperate with each other to execute each of the above processes.

[0072] The cooling effect of the wafer 10 by the gas flow path 6 described above is affected by multiple factors such as the temperature of the gas coolant, the flow rate of the gas coolant, and the opening area of ​​the flow path groove 66 of the gas flow path 6. To achieve a predetermined cooling effect, the multiple factors described above must be controlled by the control device 7. Specifically, the control device 7 controls the suction device 8 so that the product A of the temperature difference ΔT and the cooling capacity C is 10 or more.

[0073] The temperature difference ΔT is a value obtained by subtracting the temperature of the gas coolant introduced into the gas introduction path 65 from the set temperature of the wafer 10. The unit of the temperature difference ΔT is °C. The set temperature is the temperature of the wafer 10 during inspection. The temperature of the wafer 10 is a predetermined target value, and the control device 7 has information on the set temperature. Information on the temperature of the gas coolant is obtained, for example, by a temperature sensor arranged in a pipe connecting the storage tank to the gas introduction path 65. This temperature information is input to the control device 7 and is grasped by the control device 7. If the wafer holder 1 is equipped with a temperature adjustment device that adjusts the temperature of the gas coolant, the control device 7 may adjust the temperature of the gas coolant by controlling the cooling device. The larger the temperature difference ΔT, the greater the cooling effect of the wafer 10.

[0074] The cooling capacity C is a value obtained by dividing the flow rate of the gas refrigerant in the flow channel 66 by the opening area of ​​the flow channel 66. The unit of flow rate is LPM (liters per minute). Information on the flow rate is obtained, for example, by a flow meter disposed between the gas discharge path 67 and the suction device 8. The information on the flow rate is input to the control device 7 and is grasped by the control device 7. When the relationship between the operation output of the suction device 8 and the flow rate is obtained in advance, the control device 7 may determine the flow rate by calculation from the information on the operation output of the suction device 8.

[0075] The opening area of ​​the flow groove 66 related to the cooling capacity C is in mm 2 (square millimeters). The opening of the flow channel 66 opens upward from the upper surface 2U of the base 2. Because the wafer 10 is placed on the upper surface 2U, the opening area of ​​the flow channel 66 may be considered to be equal to the area where the gas refrigerant flowing through the flow channel 66 comes into contact with the wafer 10. The cooling capacity C is the value obtained by dividing the flow rate by the opening area, and may be considered to be the flow rate of the gas refrigerant per unit area of ​​the opening. When the overall flow rate of the flow channel 66 is the same, the cooling capacity C decreases as the opening area increases.

[0076] The product A of the temperature difference ΔT and the cooling capacity C is expressed in units of ℃·LPM / mm 2 The product A is an index reflecting the influence of both the temperature difference ΔT and the cooling power C on the cooling effect of the wafer 10. The larger the product A, the higher the cooling effect of the wafer 10. If the product A is 10 or more, the temperature of the wafer 10 heated by the heater 21 operating at a steady output can be reduced by 0.1° C. or more, as shown in a test example described later. The product A may be 20 or more, 50 or more, or 100 or more. There is no particular upper limit to the product A.

[0077] ≪Support structure≫ As shown in FIG. 1, the support structure 3 includes a leg member 30 and a base plate 31. The leg member 30 is a member that supports the base body 2 on the base plate 31. When the support body 20 is present, the leg member 30 supports the support body 20 on the base plate 31. The leg member 30 has a shape of, for example, a columnar or cylindrical shape. The columnar or cylindrical leg member 30 supports the support body 20 or the base body 2 by penetrating a hole provided in the heater 21. The outer diameter of the columnar or cylindrical leg member 30 is sufficiently smaller than the outer diameter of the support body 20 or the outer diameter of the base body 2. By using the columnar or cylindrical leg member 30, the contact area between the leg member 30 and the support body 20 or the contact area between the leg member 30 and the base body 2 is reduced. This suppresses heat conduction to the base plate 31 via the leg member 30, and maintains the thermal uniformity of the base body 2. Furthermore, by using the columnar or cylindrical leg member 30, a space can be formed between the heater 21 and the base plate 31. This space contributes to heat insulation between the base plate 31 and the substrate 2. The leg member 30 in this example is a cylindrical body. It is preferable to provide a plurality of leg members 30 so as to support the substrate 2 or the support body 20 in a well-balanced manner. The material of the leg member 30 is, for example, any one of alumina, mullite alumina, mullite, cordierite, steatite, and silicon nitride.

[0078] The base plate 31 is a member that serves as a base for supporting the substrate 2, the support 20, the heater 21, and the leg members 30. The material of this base plate 31 is, for example, alumina, aluminum nitride, silicon carbide, a composite material of silicon and silicon carbide, a composite material of aluminum and silicon carbide, or a composite material of aluminum, silicon, and silicon carbide.

[0079] <Embodiment 2> In the second embodiment, a wafer holder 1 including a second gas flow passage 62 for partially cooling a wafer 10 will be described with reference to Fig. 4. In Fig. 4 as well, the boundaries of each heating zone 2A are indicated by two-dot chain lines.

[0080] The second gas flow passages 62 are gas flow passages 6 that partially cool the wafer 10. Eight second gas flow passages 62 are formed in the wafer holder 1 shown in FIG. 4. Each second gas flow passage 62 includes a gas inlet passage 65, a flow passage groove 66, and a gas exhaust passage 67. The flow passage groove 66 of each second gas flow passage 62 is disposed in each heating zone 2A. The gas inlet passage 65 and the gas exhaust passage 67 have the same configuration as the first gas flow passage 61 of the first embodiment. Meanwhile, the flow passage groove 66 is configured by two independent grooves that are independent from each other. Each independent groove in the top view is a circular arc groove 66D.

[0081] The gas coolant can flow through the second gas flow paths 62 independently of each other. According to the configuration of the second embodiment, the entire surface of the wafer 10 can be quickly cooled. Moreover, according to the configuration of this example, the part of the wafer 10 that has a particularly high temperature can be intensively cooled.

[0082] <Modification> The gas inlet path 65 and the gas exhaust path 67 described in the above embodiment may open to the lower surface 2D of the base 2, as shown in Fig. 5. Here, Fig. 5 is a schematic diagram for explaining the configuration of the gas inlet path 65 and the gas exhaust path 67, and is not a drawing showing an accurate positional relationship like the cross-sectional view of Fig. 3.

[0083] 5, the gas inlet path 65 and the gas exhaust path 67 of the modified example are respectively constituted by a vertical hole connecting from the lower surface 2D of the base 2 to a first end 66A of the flow channel groove 66 and a vertical hole connecting to a second end 66B. That is, the gas inlet path 65 and the gas exhaust path 67 penetrate the base 2 in the thickness direction. In this case, it is necessary to provide through holes connecting to the openings of the gas inlet path 65 and the gas exhaust path 67 in the lower surface 2D in the support 20 and the heater 21 shown in FIG.

[0084] The gas inlet path 65 and the gas outlet path 67 that penetrate the base 2 in the thickness direction can be easily formed so as to avoid the vacuum path 4 and the refrigerant flow path 5 of the base 2. Moreover, such gas inlet path 65 and gas outlet path 67 can be easily formed by drilling holes that penetrate the base 2 in the thickness direction. The pipes connected to the gas inlet path 65 and the gas outlet path 67 in this example can be easily arranged so as not to protrude from the side surface 2C of the base 2.

[0085] <Test Example> In test example 1, the influence of temperature difference ΔT and cooling capacity C on the cooling effect of the wafer 10 was investigated by simulation. In this simulation, a state in which the heater 21 was operated to maintain the temperature of the wafer 10 at 35°C, that is, a state in which the wafer 10 was constantly heated, was simulated. The results are shown in Table 1.

[0086] The gas temperature in Table 1 is the temperature of the gas coolant introduced into the flow groove 66 of the gas flow path 6. The gas coolant is air. The evaluation temperature is the temperature of the wafer 10 heated by the heater 21. The temperature difference ΔT is the value obtained by subtracting the gas temperature from the evaluation temperature. The unit of temperature is Celsius. The opening area is the product of the length and width of the opening of the flow groove 66. When the opening area is 7.5 mm 2 The length of the opening of the flow channel 66 was 3 mm, and the width of the opening was 2.5 mm. 2 The length of the opening of the flow channel 66 was 3.0 mm, and the width of the opening was 3.0 mm. The flow rate is the flow rate of the gas refrigerant introduced into the flow channel 66. The unit of the flow rate is LPM (liters per minute). The cooling capacity C is the flow rate divided by the opening area. The cooling effect indicates the degree of decrease in temperature of the wafer 10. The unit of the cooling effect is Celsius.

[0087] [Table 1]

[0088] The results of Table 1 are shown in the graph in Figure 6. The horizontal axis of the graph is the temperature difference ΔT, and the vertical axis is the cooling effect. The black dots plot the cooling capacity C of 0.27 LPM / mm 2The data of the white circle plot shows the cooling capacity C of 1.11 LPM / mm 2 The data is for . As shown in the graph, it was found that, for a given cooling capacity C, the cooling effect increases in proportion to the temperature difference ΔT. It was also found that, for a given temperature difference ΔT, the cooling effect increases in proportion to the cooling capacity C. From these results, it is inferred that the cooling effect can be managed by the product A of the temperature difference ΔT and the cooling capacity C. For example, if you want to achieve a given cooling effect but it is difficult to increase the flow rate, increase the temperature difference ΔT so that the product A is equal to or greater than the given value, i.e., lower the temperature of the gas refrigerant.

[0089] If the product A is, for example, 12, the temperature of the wafer 10 heated by the heater 21 operating at a steady output drops by about 0.1° C. The higher the value of the product A, the higher the cooling effect becomes, and the wafer 10 can be cooled more quickly.

[0090] <Demonstration Test> In the demonstration test, a flow channel 66 was formed on the upper surface 2U of the base 2, and the cooling effect obtained when a gas refrigerant was made to flow through the flow channel 66 was measured. Specifically, a first demonstration test and a second demonstration test were carried out in which the set temperatures of the wafer 10 were different. In the first demonstration test, the wafer 10 was continuously heated by the heater 21 so that the temperature of the wafer 10 was 44°C. The temperature difference ΔT between the temperature of the wafer 10 and the temperature of the gas refrigerant was 21.78°C. The length of the opening of the flow channel 66 was 3.0 mm, the width of the opening was 3.0 mm, and the opening area of ​​the flow channel 66 was 9.0 mm. 2 The flow rate was 10 LPM. In other words, the cooling capacity C was 1.11 LPM / mm 2About 20 seconds after the gas refrigerant started to flow, the temperature of the wafer 10 stabilized at a temperature lower than the temperature before the gas refrigerant was circulated. The cooling effect was -0.238°C. The test conditions of the second demonstration test were the same as those of the first demonstration test, except for the set temperature of the wafer 10. In the second demonstration test, the wafer 10 was continuously heated by the heater 21 so that the temperature of the wafer 10 was 54°C. The temperature difference ΔT between the temperature of the wafer 10 and the temperature of the gas refrigerant was 32.1°C. About 20 seconds after the gas refrigerant started to flow, the temperature of the wafer 10 stabilized at a temperature lower than the temperature before the gas refrigerant was circulated. The cooling effect of the second demonstration test was -0.353°C. In FIG. 6, the results of the first demonstration test and the second demonstration test are shown as diamond-shaped plots. The results of the demonstration test were approximately located on the dotted line connecting the white circle plots in FIG. 6. [Explanation of symbols]

[0091] 1 Wafer holder 10 Wafers 2 Base 2A Heat Zone 2C side 2D bottom side 2U top 20 Support 21 Heater 3 Support structure 30 Leg members 31 Base plate 4 Vacuum Path 4h horizontal hole, 4r annular groove, 4v vertical hole 5 Coolant flow path 6 Gas flow path 61 first gas flow passage, 62 second gas flow passage 65 gas inlet passage, 66 flow channel, 67 gas outlet passage 65h,67h horizontal hole, 65v,67v vertical hole 66A first end, 66B second end, 66C C-groove, 66D arc groove 7 Control device 8 Suction device 100 Semiconductor processing equipment

Claims

1. a disk-shaped base having an upper surface on which a wafer is placed; a vacuum path for adsorbing the wafer to the top surface; a gas flow path for flowing a gas coolant for cooling the wafer; The gas flow path is A flow channel opening on the upper surface; a gas introduction passage disposed inside the substrate and connected to a first end of the flow channel; A gas exhaust channel is disposed inside the base and connected to a second end of the flow channel. Wafer holder.

2. 2. The wafer holder according to claim 1, further comprising a coolant passage disposed inside said base for circulating a coolant for cooling said base.

3. 3. The wafer holder according to claim 1, further comprising a heater disposed inside said base or on a lower surface of said base.

4. the gas flow path is a first gas flow path that cools the entire surface of the wafer, 3. The wafer holding table according to claim 1, wherein the flow passage groove in the first gas flow passage is formed over the entire surface of the upper surface.

5. 5. The wafer holder according to claim 4, wherein said flow passage groove is formed of a plurality of C-shaped grooves concentrically arranged on said upper surface.

6. the gas passage is a second gas passage for partially cooling the wafer; 3. The wafer holding table according to claim 1, wherein the flow passage groove in the second gas flow passage is formed in a portion of the upper surface.

7. The substrate includes a plurality of heating zones in a top view, 7. The wafer holder according to claim 6, wherein the flow passage groove is disposed in each of the plurality of heating zones.

8. 3. The wafer holding table according to claim 1, wherein said gas inlet passage and said gas outlet passage are open to a side surface of said base.

9. 3. The wafer holding table according to claim 1, wherein said gas inlet passage and said gas outlet passage are open to a lower surface of said base.

10. Using the wafer holder according to claim 1 or 2, The gas is sucked from the gas exhaust passage to create a negative pressure inside the gas passage, so that the gas refrigerant is introduced from the gas introduction passage into the passage groove. How to use the wafer holder.

11. The gas is sucked through the gas exhaust passage so that a product A of a temperature difference ΔT and a cooling capacity C is 10 or more; the temperature difference ΔT is a value obtained by subtracting the temperature of the gas coolant introduced into the gas introduction path from the set temperature of the wafer, the cooling capacity C is a value obtained by dividing the flow rate of the gas refrigerant in the flow channel by the opening area of ​​the flow channel on the upper surface, 11. The method of claim 10, wherein the temperature is in degrees Celsius, the flow rate is in liters per minute, and the opening area is in square millimeters.

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