Wafer-holding table and semiconductor processing device

Abstract

A wafer-holding table disposed in a chamber includes: a mounting plate having an upper surface on which a wafer is mounted, and a lower surface opposite to the upper surface; a support body for supporting the lower surface; and a first reflection plate disposed at a position separated downward from the lower surface. A distance L between the lower surface and the first reflection plate is 0.1-60 mm inclusive, and the emissivity of the first reflection plate is equal to or less than the emissivity of the mounting plate.

Description

Wafer holder and semiconductor processing apparatus

[0001] The present disclosure relates to a wafer holder and a semiconductor processing apparatus.

[0002] Japanese Patent Application Laid-Open No. 2003-129999 and Japanese Patent Application Laid-Open No. 2003-129999 disclose techniques relating to a wafer holder arranged within a chamber. The wafer holder has an upper surface on which a wafer is placed. A semiconductor processing apparatus in which a wafer holder is arranged within a chamber is, for example, a film deposition apparatus that forms a coating on the surface of a wafer.

[0003] JP 2018-505551 A JP 2020-155519 A

[0004] The wafer holder of the present disclosure is a wafer holder placed within a chamber, and comprises: a mounting plate having an upper surface on which a wafer is placed and a lower surface opposite the upper surface; a support body supporting the lower surface; and a first reflector placed at a position spaced below the lower surface, wherein the distance L between the lower surface and the first reflector is 0.1 mm or more and 60 mm or less, and the emissivity of the first reflector is equal to or less than the emissivity of the mounting plate.

[0005] Fig. 1 is a cross-sectional view showing an example of a semiconductor processing apparatus including a wafer holder according to embodiment 1. Fig. 2 is a half cross-sectional view showing an enlarged upper portion of the semiconductor processing apparatus shown in Fig. 1. Fig. 3 is a half cross-sectional view of an upper portion of the semiconductor processing apparatus further including a sidewall portion in addition to the configuration shown in Fig. 2.

[0006] [Problem to be Solved by the Present Disclosure] In semiconductor processing equipment, wafers must be maintained at a predetermined temperature or higher. A heater is installed inside the wafer holder, and the wafer temperature is maintained by heating the wafer holder to a high temperature. However, because the heat from the wafer holder is dissipated into the chamber and then from the chamber to the outside, a large amount of power is consumed to maintain a constant temperature of the wafer holder.

[0007] An object of the present disclosure is to provide a wafer holder that can reduce the amount of power consumed by a semiconductor processing apparatus.

[0008] Effect of the Present Disclosure The wafer holder of the present disclosure can reduce the power consumption of the semiconductor processing apparatus by using the first reflector provided on the wafer holder.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] <1> A wafer holder according to one embodiment is a wafer holder arranged within a chamber, and comprises: a mounting plate having an upper surface on which a wafer is placed and a lower surface opposite the upper surface; a support body supporting the lower surface; and a first reflector arranged at a position spaced downward from the lower surface, wherein the distance L between the lower surface and the first reflector is 0.1 mm or more and 60 mm or less, and the emissivity of the first reflector is equal to or less than the emissivity of the mounting plate.

[0011] Emissivity is an index that indicates the ease with which an object radiates heat and is a dimensionless quantity between 0 and 1. A member with low emissivity is more likely to reflect radiant heat. By positioning a first reflector, which has an emissivity equal to or lower than that of the mounting plate, at a predetermined distance from the underside of the mounting plate, heat is less likely to dissipate to the region below the first reflector in the chamber, and heat is more likely to remain in the region above the first reflector. Here, the emissivity of the mounting plate is the average emissivity of the underside of the mounting plate facing the first reflector. Therefore, the temperature of the mounting plate is less likely to drop, and the power required to maintain the mounting plate at a predetermined temperature is reduced. This reduces the power consumption of a semiconductor processing apparatus equipped with the wafer holder.

[0012] Here, the configuration in which the first reflector is in contact with the underside of the mounting plate is almost equivalent to a configuration in which the mounting plate is thicker, i.e., a configuration in which the heat capacity of the mounting plate is increased, and the power required to heat the mounting plate to a desired temperature increases. Therefore, if the first reflector is in contact with the underside of the mounting plate, the power consumption of the semiconductor processing apparatus will not be reduced.

[0013] <2> In the wafer holder according to the above item <1>, the first reflecting plate may be made of any one of stainless steel, aluminum oxide, and aluminum nitride.

[0014] For example, if the semiconductor processing apparatus is a film deposition apparatus, the temperature near the support plate will be 500°C or higher. Stainless steel, aluminum oxide, and aluminum nitride all have excellent heat resistance and can be used even when placed near a high-temperature support plate. Aluminum nitride, in particular, has excellent heat resistance. A first reflector made of aluminum nitride is less likely to develop defects such as cracks at high temperatures of 500°C or higher.

[0015] <3> In the wafer holder described in <2> above, the first reflecting plate may be made of stainless steel, and the distance L may be 0.1 mm or more and 50 mm or less.

[0016] As shown in Test Example 2 described later, if the distance L between the mounting plate and the first reflecting plate made of stainless steel is 0.1 mm or more and 50 mm or less, the power consumption of the semiconductor processing apparatus is likely to be reduced.

[0017] <4> In the wafer holder described in <2> above, the first reflector may be made of aluminum oxide, and the distance L may be 0.1 mm or more and 40 mm or less.

[0018] As shown in Test Example 3 described later, if the distance L between the mounting plate and the first reflecting plate made of aluminum oxide is 0.1 mm or more and 40 mm or less, the power consumption of the semiconductor processing apparatus is likely to be reduced.

[0019] <5> In the wafer holder described in <2> above, the first reflector may be made of aluminum nitride, and the distance L may be 0.1 mm or more and 40 mm or less.

[0020] As shown in Test Example 4 described later, if the distance L between the mounting plate and the first reflecting plate made of aluminum nitride is 0.1 mm or more and 40 mm or less, the power consumption of the semiconductor processing apparatus is likely to be reduced.

[0021] <6> The wafer holder according to any one of <1> to <5> above, further comprising a spacer disposed between the lower surface and the first reflector, and the first reflector may be fixed to the lower surface so as to ensure the distance L by the spacer.

[0022] Since the first reflector is fixed to the underside of the mounting plate via the spacer, the first reflector does not come into contact with any components other than the mounting plate, such as the support body. Since no conduction path is formed from the mounting plate through the support body to the first reflector, heat dissipation from the mounting plate to the first reflector due to conduction is suppressed.

[0023] <7> A semiconductor processing apparatus according to an embodiment includes: the wafer holder according to any one of <1> to <6> above; and a chamber in which the wafer holder is disposed.

[0024] In the semiconductor processing apparatus, the first reflector has an emissivity of 0.5 or more, which allows heat to remain in the region above the first reflector in the chamber. This makes it difficult for the temperature of the mounting plate to drop, reducing the amount of power required to maintain the mounting plate at a desired temperature. This reduces the amount of power consumed by the semiconductor processing apparatus.

[0025] <8> The semiconductor processing apparatus described in <7> above may further include a second reflector disposed inside the chamber, the chamber having an inner bottom surface facing the lower surface of the first reflector, the second reflector being disposed on the inner bottom surface, and the emissivity of the second reflector being less than the emissivity of the inner bottom surface.

[0026] A member with low emissivity tends to reflect radiant heat. The second reflector with low emissivity placed on the inner bottom surface of the chamber tends to reflect radiant heat from the mounting plate and the first reflector back into the chamber. This makes it difficult for the temperature inside the chamber to drop, and also makes it difficult for the temperature of the mounting plate placed inside the chamber to drop. As a result, the power consumption of the semiconductor processing equipment is reduced.

[0027] <9> The semiconductor processing apparatus according to <7> or <8> above, further comprising a third reflector disposed inside the chamber, the chamber having an inner surface facing the outer peripheral surface of the support, the third reflector disposed on the inner surface, and the emissivity of the third reflector may be less than the emissivity of the inner surface.

[0028] The third reflector, which has low emissivity and is located on the inner surface of the chamber, easily reflects radiant heat from the mounting plate and the first reflector back into the chamber. This makes it difficult for the temperature inside the chamber to drop, and also makes it difficult for the temperature of the mounting plate placed inside the chamber to drop. As a result, the power consumption of the semiconductor processing equipment is reduced.

[0029] [Details of the Embodiments of the Present Disclosure] Specific examples of wafer holders according to embodiments of the present disclosure will now be described with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0030] <Embodiment 1> <Overall Configuration> A semiconductor processing apparatus 1 and a wafer holder 2 according to embodiment 1 will be described with reference to Figures 1 and 2. The semiconductor processing apparatus 1 shown in Figures 1 and 2 is a film formation apparatus for forming a film on a wafer (not shown). As shown in Figure 1, the semiconductor processing apparatus 1 includes a wafer holder 2 disposed in a chamber 9. The semiconductor processing apparatus 1 of this example includes a configuration for reducing the amount of power consumed by the semiconductor processing apparatus 1. Below, the basic configuration of the wafer holder 2 and chamber 9 included in the semiconductor processing apparatus 1 of this example will be described, followed by a configuration for reducing the amount of power consumed by the semiconductor processing apparatus 1.

[0031] <Wafer Support Table> The wafer support table 2 includes a mounting plate 20 and a support 25. In this example, the mounting plate 20 has a disk shape. As shown in FIG. 2 , the mounting plate 20 has an upper surface 20U that faces upward in the semiconductor processing apparatus 1, and a lower surface 20L that faces downward. In other words, the lower surface 20L is the surface opposite the upper surface 20U. A wafer is placed on the upper surface 20U of the mounting plate 20 when a coating is formed on the surface of the wafer in the semiconductor processing apparatus 1 of this example. The wafer is, for example, a silicon wafer.

[0032] The material of the mounting plate 20 is, for example, ceramics. Examples of ceramics include aluminum nitride, aluminum oxide, and silicon carbide. The material of the mounting plate 20 may also be a composite material of the above ceramics and a metal. Examples of metals include aluminum, aluminum alloy, copper, and copper alloy. Aluminum nitride is particularly suitable as a material for the mounting plate 20 because of its excellent heat resistance. The emissivity of aluminum nitride is, for example, approximately 0.85 at 550°C.

[0033] A heater 21 is disposed inside the mounting plate 20. The heater 21 is a heat source that heats the wafer placed on the upper surface 20U of the mounting plate 20. The heat of the heater 21 is transferred from the inside of the mounting plate 20 to the upper surface 20U, heating the wafer.

[0034] The heater 21 in this example includes a resistance heating element 21R, a power supply that supplies power to the resistance heating element 21R, and a power line connecting the resistance heating element 21R and the power supply. The power supply and power line are not shown in FIG. 1 . The resistance heating element 21R in this example is a circuit pattern formed along an imaginary plane parallel to the upper surface 20U. The material of the resistance heating element 21R is, for example, one selected from the group consisting of stainless steel, nickel, nickel alloy, silver, silver alloy, tungsten, tungsten alloy, molybdenum, molybdenum alloy, chromium, and chromium alloy. The nickel alloy is, for example, nichrome.

[0035] A temperature sensor (not shown) is disposed inside the mounting plate 20. The temperature sensor is for monitoring the temperature of the mounting plate 20. The heater 21 is controlled based on temperature information from the temperature sensor.

[0036] Additionally, a coolant flow path (not shown) may be arranged inside the mounting plate 20. A coolant is supplied to the coolant flow path as needed. The coolant flow path is configured to quickly cool the mounting plate 20 heated by the heater 21. By quickly cooling the mounting plate 20, the time required to start processing a new wafer can be shortened.

[0037] As shown in FIG. 1 , the support 25 supports the lower surface 20L of the mounting plate 20. The support 25 has a cylindrical shape. The shape of the support 25 is not particularly limited. In this example, the support 25 is cylindrical. The support 25 is arranged roughly concentrically with the mounting plate 20. In this example, the mounting plate 20 is attached on the support 25 so that the central axis of the cylindrical support 25 and the central axis of the disk-shaped mounting plate 20 are coaxial. Power lines and the like connected to the resistance heating element 21R are arranged inside the support 25. In addition, sensor lines and the like extending from a temperature sensor are arranged inside the support 25.

[0038] The support 25 has an upper end 25U and a lower end 25L. The upper end 25U and the lower end 25L each have a flange shape. The upper end 25U is attached to the lower surface 20L of the mounting plate 20. A sealing member (not shown) is disposed between the upper end 25U and the lower surface 20L. The lower end 25L is attached to the bottom surface of the chamber 9, which will be described later. A sealing member (not shown) is disposed between the lower end 25L and the bottom surface of the chamber 9. These sealing members keep the interior of the support 25 airtight. Although not shown, holes are formed in the bottom surface of the chamber 9 for leading out the power lines of the heater 21 and the sensor lines of the temperature sensor.

[0039] The material of the support 25 is, for example, ceramics. The material of the support 25 may be the same as or different from the material of the mounting plate 20.

[0040] <Chamber> The chamber 9 serves to separate the space for film formation from the outside. The chamber 9 in this example includes an upper chamber 9U and a lower chamber 9L. The upper chamber 9U has an inner peripheral surface shape that follows the outer shape of the mounting plate 20. The lower chamber 9L has an inner peripheral surface shape that follows the outer shape of the support 25. The internal space of the upper chamber 9U and the internal space of the lower chamber 9L are connected to form the internal space of the chamber 9. In the semiconductor processing apparatus 1 in this example, a reaction gas is filled in the internal space of the chamber 9. The reaction gas is sealed in the internal space of the chamber 9 so as not to leak into the external space.

[0041] The chamber 9 is made of, for example, an aluminum alloy. The inner surface includes an inner bottom surface 90 and an inner side surface 91, which will be described later. The inner surface of the chamber 9 may be subjected to a surface treatment. The emissivity of the inner surface of the chamber 9 changes depending on the surface treatment. The emissivity of the inner surface of the chamber 9 can be, for example, approximately 0.2 to 0.9.

[0042] The chamber 9 in this example is provided with a shower head 95 that sprays a reaction gas toward a wafer placed on the upper surface 20U (FIG. 2) of the mounting plate 20 during film formation. The shower head 95 is disposed in the ceiling portion of the upper chamber 9U.

[0043] <Configuration for Reducing Power Consumption of Semiconductor Processing Equipment> The semiconductor processing equipment 1 of this example is equipped with a first reflector 3, a second reflector 4, and a third reflector 5 as a configuration for reducing power consumption of the semiconductor processing equipment 1. The first reflector 3 is provided on the wafer holder 2. The second reflector 4 and the third reflector 5 are provided on the chamber 9. The second reflector 4 and the third reflector 5 are not essential components. The following description will mainly refer to FIG. 2.

[0044] [First Reflector] The first reflector 3 is positioned below and away from the underside 20L of the mounting plate 20. The emissivity of the first reflector 3 is equal to or less than that of the mounting plate 20. A first reflector 3 with an emissivity equal to or less than that of the mounting plate 20 easily reflects radiant heat from the mounting plate 20 upward. By positioning the first reflector 3 at a predetermined distance from the underside 20L, heat is less likely to dissipate to the region below the first reflector 3 within the chamber 9, and heat is more likely to remain in the region above the first reflector 3. As a result, the temperature of the mounting plate 20 is less likely to drop, and the power required to maintain the mounting plate 20 at a desired temperature is reduced. Therefore, the wafer holder 2 can reduce the power consumption of the semiconductor processing apparatus 1.

[0045] Here, unlike this example, if the first reflecting plate 3 were bonded to the mounting plate 20, the mounting plate 20 would be distorted due to the difference between the linear expansion coefficients of the first reflecting plate 3 and the mounting plate 20, which could reduce the flatness of the mounting plate 20. If the first reflecting plate 3 is positioned away from the mounting plate 20 as in this example, it is possible to prevent distortion of the mounting plate 20 due to the difference in linear expansion coefficients.

[0046] The distance L between the first reflecting plate 3 and the lower surface 20L is 0.1 mm or more and 60 mm or less. If the distance L is in the range of 0.1 mm or more and 60 mm or less, it is possible to reduce the power consumption of the semiconductor processing apparatus 1. Here, when the first reflecting plate 3 is in contact with the lower surface 20L of the mounting plate 20, heat is easily transferred from the mounting plate 20 to the first reflecting plate 3 by heat conduction.

[0047] In the semiconductor processing apparatus 1 of this embodiment, the mounting plate 20 is heated to, for example, 500°C or higher during film formation. In other words, the mounting plate 20 is repeatedly exposed to temperature changes between room temperature and high temperatures of 500°C or higher. The first reflector 3 disposed near the mounting plate 20 is also exposed to drastic temperature changes. Therefore, the first reflector 3 only needs to be made of a material with excellent heat resistance. Heat resistance here means that the first reflector 3 can be used at the ambient temperature near the first reflector 3 during film formation, for example, 500°C. Examples of materials for such a first reflector 3 include stainless steel, aluminum oxide, or aluminum nitride.

[0048] Stainless steel tends to have low emissivity. For example, the emissivity of SUS316, a type of stainless steel, is approximately 0.15 under the temperature conditions during film formation. A first reflecting plate 3 with low emissivity tends to reflect radiant heat from the mounting plate 20 upward. Therefore, a first reflecting plate 3 made of stainless steel tends to reduce the power consumption of the semiconductor processing apparatus 1.

[0049] When the first reflector 3 is made of stainless steel, the power consumption of the semiconductor processing apparatus 1 is likely to be reduced if the distance L is 0.1 mm or more and 50 mm or less. The distance L may be 0.1 mm or more and 20 mm or less, or may be 2 mm or more and 10 mm or less. When an improvement in the wafer range shown in Test Example 2 is desired, the distance L may be, for example, 1 mm or more and 15 mm or less.

[0050] The emissivity of aluminum oxide changes with temperature. The emissivity of aluminum oxide is approximately 0.66 at 450°C, and decreases as the temperature increases. Under the temperature conditions during film formation, the emissivity of aluminum oxide is approximately 0.5.

[0051] When the first reflector 3 is made of aluminum oxide, if the distance L is 0.1 mm or more and 40 mm or less, the power consumption of the semiconductor processing apparatus 1 is likely to be reduced. The distance L may be 1 mm or more and 25 mm or less, 1 mm or more and 15 mm or less, or 3 mm or more and 6 mm or less. When an improvement in the wafer range shown in Test Example 3 is desired, the distance L may be, for example, 5 mm or more and 7 mm or less.

[0052] Here, aluminum oxide expands more easily than aluminum nitride in environments above 500°C. If the first reflector 3 made of aluminum oxide is large, a large temperature difference between the center and outer periphery of the first reflector 3 may cause cracks in the first reflector 3 due to the thermal stress. Therefore, it is preferable that the first reflector 3 made of aluminum oxide is constructed by connecting multiple divided pieces. In a first reflector 3 made of multiple divided pieces, cracks are less likely to occur in each divided piece. Therefore, the function of the first reflector 3 is more likely to be maintained. The number of divided pieces is, for example, three or four.

[0053] The emissivity of aluminum nitride changes with temperature. At 460°C, the emissivity is approximately 0.79, and increases as the temperature increases. At 550°C, the emissivity of aluminum nitride is approximately 0.85.

[0054] Aluminum nitride has excellent heat resistance. The first reflector 3 made of aluminum nitride is unlikely to expand in an environment of 500°C or higher, and cracks caused by expansion are unlikely to occur. Therefore, the first reflector 3 made of aluminum nitride may be formed from a single member. Such a first reflector 3 is easy to manufacture and handle.

[0055] When the first reflector 3 is made of aluminum nitride, the power consumption of the semiconductor processing apparatus 1 is likely to be reduced if the distance L is 0.1 mm or more and 40 mm or less. The distance L may be 1 mm or more and 20 mm or less, or may be 2 mm or more and 10 mm or less. When an improvement in the wafer range shown in Test Example 4 is desired, the distance L may be, for example, 2 mm or more and 15 mm or less.

[0056] In this example, the first reflector 3 has an annular shape. The outer peripheral surface of the support 25 and the inner peripheral surface of the first reflector 3 are spaced apart by 1 mm or more in a direction from the central axis of the support 25 toward the outer periphery of the support 25. Because the first reflector 3 is spaced apart from the support 25, i.e., the inner peripheral surface of the annular first reflector 3 is not in contact with the support 25, no heat transfer path is formed from the mounting plate 20 through the support 25 to the first reflector 3. Therefore, heat from the mounting plate 20 is less likely to dissipate to a region below the first reflector 3. The first reflector 3 may be positioned so as to overlap the upper end 25U of the support 25 in the height direction, or may be positioned below the upper end 25U but not overlapping the upper end 25U. When the first reflector 3 is positioned so as not to overlap the upper end 25U, the inner diameter of the first reflector 3 may be smaller than the outer diameter of the upper end 25U. An upper end 25U of the support 25 is spaced apart from an upper surface 3U of the first reflector 3 by 1 mm or more in a direction along the axis of the support 25. In this case, the gap formed between the inner peripheral surface of the first reflector 3 and the outer peripheral surface of the support 25 has a curved shape, so that heat from the mounting plate 20 is less likely to dissipate to a region below the first reflector 3.

[0057] The outer diameter of the annular first reflector 3 may be smaller, the same as, or larger than the outer diameter of the mounting plate 20. The first reflector 3 covers most of the lower surface 20L of the mounting plate 20, making it easier to retain heat in the region above the first reflector 3. For example, when the area of ​​the lower surface 20L excluding the portion connected to the upper end 25U of the support 25 is taken as area S0 and the area of ​​the upper surface 3U of the first reflector 3 is taken as S1, the area ratio S1 / S0 is 0.9 or greater. The upper surface 3U of the first reflector 3 is the surface facing the lower surface 20L of the mounting plate 20.

[0058] The thickness of the first reflector 3 is, for example, 1 mm or more and 10 mm or less. If the thickness of the first reflector 3 is 1 mm or more, heat is more likely to be retained in the region above the first reflector 3. If the thickness of the first reflector 3 is 10 mm or less, an increase in the size of the first reflector 3, and therefore an increase in the size of the semiconductor processing apparatus 1, is suppressed. The thickness of the first reflector 3 may be 2 mm or more and 5 mm or less.

[0059] In this example, the first reflecting plate 3 is fixed to the lower surface 20L of the mounting plate 20 together with a spacer 30. The spacer 30 is disposed between the mounting plate 20 and the first reflecting plate 3. The upper end surface of the spacer 30 is in contact with the lower surface 20L of the mounting plate 20, and the lower end surface of the spacer 30 is in contact with the upper surface 3U of the first reflecting plate 3. The spacer 30 allows the distance L to be determined accurately.

[0060] The spacer 30 in this example has a cylindrical shape. A fixing member 31 passes through the interior of the spacer 30. The fixing member 31 in this example is a screw. The head of the screw abuts against the lower surface 3L of the first reflector 3. The tip of the screw is screwed into the mounting plate 20.

[0061] If the thermal conductivity of the spacer 30 is low, the heat conduction from the mounting plate 20 to the first reflector 3 is reduced. Similarly, if the thermal conductivity of the fixing member 31 is low, the heat conduction from the mounting plate 20 to the first reflector 3 is reduced. Therefore, if the spacer 30 and the fixing member 31 are made of a material with a thermal conductivity of 50 W / mK or less, for example, the heat conduction from the mounting plate 20 to the first reflector 3 is reduced. The material of the spacer 30 and the fixing member 31 is aluminum oxide, for example. In consideration of heat resistance and the like, the material of the spacer 30 and the fixing member 31 may be silicon nitride or aluminum nitride, for example.

[0062] As shown in FIG. 3 , a sidewall portion 35 may be disposed at the outer periphery of the first reflector 3. The outer periphery of the first reflector 3 includes the outer periphery of the first reflector 3 and the vicinity of the outer periphery on the upper surface 3U. The sidewall portion 35 is a member that covers the gap between the mounting plate 20 and the first reflector 3 near the outer periphery of the first reflector 3. In this example, the sidewall portion 35 is an annular member that conforms to the outer periphery of the first reflector 3. The sidewall portion 35 makes it difficult for heat in the gap between the mounting plate 20 and the first reflector 3 to escape from the gap. This makes it difficult for the temperature of the mounting plate 20 to drop, and facilitates reducing the power consumption of the semiconductor processing apparatus 1. Furthermore, the sidewall portion 35 makes it difficult for reaction gas to flow into the gap between the mounting plate 20 and the first reflector 3. This prevents the lower surface 20L of the mounting plate 20 and the upper surface 3U of the first reflector 3 from being coated.

[0063] The side wall portion 35 may be formed integrally with the first reflecting plate 3. In this case, the upper end of the side wall portion 35 may be in contact with the lower surface 20L of the mounting plate 20, or may be spaced apart from the lower surface 20L. If the upper end of the side wall portion 35 is spaced apart from the lower surface 20L of the mounting plate 20, heat conduction from the mounting plate 20 to the first reflecting plate 3 is suppressed.

[0064] The sidewall portion 35 may be a member independent of the first reflector 3. In this case, the sidewall portion 35 may be fixed to the first reflector 3 or to the mounting plate 20. The sidewall portion 35 may be made of the same material as the first reflector 3, or may be made of a different material. If the sidewall portion 35 is made of a different material from the first reflector 3, a low thermal conductivity of the sidewall portion 35 will suppress the conduction of heat from the mounting plate 20 to the first reflector 3. For example, the thermal conductivity of the sidewall portion 35 is 50 W / mK or less. The sidewall portion 35 may be made of aluminum oxide, for example. In consideration of heat resistance and the like, the sidewall portion 35 may be made of silicon nitride or aluminum nitride, for example.

[0065] The side wall portion 35 may also serve as the spacer 30. That is, the side wall portion 35 may be sandwiched between the lower surface 20L of the mounting plate 20 and the upper surface 3U of the first reflecting plate 3. In this case, the side wall portion 35 functions as the spacer 30.

[0066] [Second reflector and third reflector] The semiconductor processing apparatus 1 having the first reflector 3 may further have a configuration in which it has a second reflector 4 but not a third reflector 5, or a configuration in which it has a third reflector 5 but not the second reflector 4, or a configuration in which it has both the second reflector 4 and the third reflector 5.

[0067] The second reflector 4 is disposed on the inner bottom surface 90 of the chamber 9. The inner bottom surface 90 is the surface facing the lower surface 3L of the first reflector 3. In this example, it is the surface of the inner circumferential surface of the upper chamber 9U that faces the lower surface 3L of the first reflector 3.

[0068] The emissivity of the second reflector 4 is lower than the emissivity of the inner bottom surface 90 of the chamber 9. The second reflector 4, which has a low emissivity, easily reflects radiant heat from the mounting plate 20 and the first reflector 3 into the chamber 9. Therefore, the temperature inside the chamber 9 is less likely to decrease, and the temperature of the mounting plate 20 placed inside the chamber 9 is also less likely to decrease. As a result, the power consumption of the semiconductor processing apparatus 1 is reduced.

[0069] The second reflector 4 may be in contact with the inner bottom surface 90, or may be disposed at a position separated from the inner bottom surface 90. In particular, if the second reflector 4 is in contact with the inner bottom surface 90, the temperature inside the chamber 9 is less likely to drop, and the power consumption of the semiconductor processing apparatus 1 is more likely to be reduced. The second reflector 4 may be adhered to the inner bottom surface 90, or may be vapor-deposited on the inner bottom surface 90.

[0070] The thickness of the second reflector 4 is, for example, 1 mm or more and 6 mm or less. If the thickness of the second reflector 4 is 1 mm or more, the second reflector 4 easily reflects radiant heat. If the thickness of the second reflector 4 is 6 mm or less, when the second reflector 4 is adhered to the inner bottom surface 90, the second reflector 4 can be easily processed into a shape that conforms to the inner bottom surface 90. Furthermore, when the second reflector 4 is formed by vapor deposition, the time required to form the second reflector 4 is not too long. The thickness of the second reflector 4 may be 2 mm or more and 4 mm or less.

[0071] The third reflector 5 is disposed on an inner surface 91 of the chamber 9. The inner surface 91 is a surface facing the outer peripheral surface of the support 25. In this example, the inner surface 91 is a surface of the inner peripheral surface of the upper chamber 9U facing the outer peripheral surface of the support 25.

[0072] The emissivity of the third reflector 5 is lower than the emissivity of the inner surface 91 of the chamber 9. The third reflector 5, which has a low emissivity, easily reflects radiant heat from the mounting plate 20 and the first reflector 3 into the chamber 9. Therefore, the temperature inside the chamber 9 is less likely to decrease, and the temperature of the mounting plate 20 placed inside the chamber 9 is also less likely to decrease. As a result, the power consumption of the semiconductor processing apparatus 1 is reduced.

[0073] The third reflector 5 may be in contact with the inner surface 91, or may be disposed at a position separated from the inner surface 91. In particular, if the third reflector 5 is in contact with the inner surface 91, the temperature inside the chamber 9 is less likely to decrease, and the power consumption of the semiconductor processing apparatus 1 is more likely to be reduced. The third reflector 5 may be bonded to the inner surface 91, or may be vapor-deposited on the inner surface 91.

[0074] The thickness of the third reflector 5 is, for example, 0.5 mm or more and 3 mm or less. If the thickness of the third reflector 5 is 0.5 mm or more, the third reflector 5 easily reflects radiant heat. If the thickness of the third reflector 5 is 3 mm or less, when the third reflector 5 is adhered to the inner surface 91, the third reflector 5 can be easily processed into a shape that conforms to the inner surface 91. In particular, if the thickness of the third reflector 5 is 1 mm or less, processing is easy. Furthermore, when the third reflector 5 is formed by vapor deposition, the time required to form the third reflector 5 is not too long. The thickness of the third reflector 5 may be 0.5 mm or more and 1 mm or less.

[0075] The second reflector 4 and the third reflector 5 are made of a material with an emissivity of, for example, 0.15 or less. Such a material is, for example, a metal such as an aluminum alloy. An example of an aluminum alloy is A5052, an internationally registered alloy number. A5052 is an aluminum alloy containing iron, copper, manganese, magnesium, chromium, zinc, and titanium, with the remainder being aluminum and unavoidable impurities. The materials of the second reflector 4 and the third reflector 5 may be the same or different. However, if the inner surface of the chamber 9 is subjected to a surface treatment such as anodizing or sandblasting, the emissivity of the inner surface of the chamber 9 will change depending on the surface treatment. For example, if the emissivity of the inner surface of the chamber 9 is high, such as approximately 0.9, the materials of the second reflector 4 and the third reflector 5 may be made of a material with an emissivity of 0.75 or less.

[0076] The second reflector 4 and the third reflector 5 are disposed at positions farther from the mounting plate 20 than the first reflector 3. Therefore, the second reflector 4 and the third reflector 5 are not required to have the same heat resistance as the first reflector 3.

[0077] <Test Example> In a test example, a simulation was performed to examine the effect of the first reflector 3 in reducing the amount of power consumed by the semiconductor processing apparatus 1. The simulation was performed using multiphysics analysis software from Ansys.

[0078] Test Example 1 Test Example 1 investigated the effect of the presence or absence of the first reflector 3 on reducing the amount of power consumption of the semiconductor processing apparatus 1. An overview of the samples on which the effect was investigated is shown below.

[0079] The diameter of the mounting plate 20 of the semiconductor processing apparatus 1 of Sample No. 1-1 was 350 mm, and the thickness of the mounting plate 20 was 22 mm. The material of the mounting plate 20 was aluminum nitride. The emissivity of the mounting plate 20 at 550°C was 0.85. The semiconductor processing apparatus 1 of Sample No. 1-1 had a reference configuration that did not have the first reflector 3, the second reflector 4, and the third reflector 5. Hereinafter, Sample No. 1-1 will be referred to as the reference sample.

[0080] Sample No. 1-2 differs from Sample No. 1-1 in that it includes a first reflector 3. The material of the first reflector 3 was stainless steel, specifically SUS316. The emissivity of stainless steel at 550°C was 0.15. The thickness of the first reflector 3 was 3 mm. In addition, the distance L from the lower surface 20L of the mounting plate 20 to the upper surface 3U of the first reflector 3 was 4 mm.

[0081] Sample No. 1-3 differed from Sample No. 1-2 in the material of the first reflector 3. The material of the first reflector 3 was aluminum oxide. The emissivity of aluminum oxide at 550°C was 0.5. The thickness of the first reflector 3 was 3 mm. In addition, the distance L from the lower surface 20L of the mounting plate 20 to the upper surface 3U of the first reflector 3 was 4 mm.

[0082] Sample No. 1-4 differs from Sample No. 1-2 and Sample No. 1-3 in the material of the first reflector 3. The material of the first reflector 3 was aluminum nitride. The emissivity of aluminum nitride at 550°C was 0.85. The thickness of the first reflector 3 was 3 mm. The distance L was 5 mm.

[0083] For each sample, the entire mounting plate 20 was heated to 550°C or higher from room temperature, and the power consumption and wafer range were determined by simulation when the temperature of 550°C was maintained for 30 minutes. The power consumption values ​​were calculated relative to Sample No. 1-1, which was set to 100% (percent). The wafer range was the temperature variation on the upper surface 20U of the mounting plate 20. Specifically, the temperatures were measured at the center of the upper surface 20U and at positions 35 mm apart from the center toward the periphery. The difference between the maximum and minimum temperatures was the wafer range. The unit of wafer range is °C. The measurement results are shown in Table 1. In Table 1, stainless steel is referred to as "stainless steel," aluminum nitride as "AlN," and aluminum oxide as "alumina." This also applies to Test Examples 2 to 5 below.

[0084]

[0085] As shown in Table 1, it was found that by placing the first reflector 3 at a distance below the mounting plate 20, power consumption could be reduced by approximately 10% compared to the reference sample. It was also found that the first reflector 3 could improve the wafer range. A small wafer range means that there is little variation in the temperature of the upper surface 20U of the mounting plate 20, so the wafer can be heated uniformly. The temperature of the upper surface 20U was highest at the center, decreased as the distance from the center increased, and then rose again.

[0086] Test Example 2 In Test Example 2, the influence of the distance L from the lower surface 20L of the mounting plate 20 to the upper surface 3U of the first reflector 3 on the power consumption Q and the wafer range was investigated by simulation. The material of the first reflector 3 was SUS316. The thickness of the first reflector 3 was 3 mm.

[0087] Sample No. 2-1 is a reference sample having the same configuration as Sample No. 1-1 of Test Example 1, i.e., not including the first reflector 3. The only difference between Samples No. 2-2 to 2-22 is the distance L between the upper surface 3U of the first reflector 3 made of SUS316 and the lower surface 20L of the mounting plate 20. The measurement results are shown in Table 2.

[0088]

[0089] As shown in Table 2, it was found that a reduction in power consumption was achieved when the distance L was 0.1 mm or more and 70 mm or less. When the distance L was 0.1 mm or more and 50 mm or less, the power consumption was reduced to 90% or less of the reference sample. When the distance L was 0.1 mm or more and 40 mm or less, the power consumption was reduced to 86% or less of the reference sample. Furthermore, when the distance L was 0.1 mm or more and 20 mm or less, the power consumption was reduced to 82% or less of the reference sample. When the distance L was 2 mm or more and 10 mm or less, the power consumption was reduced to 81% or less of the reference sample. Furthermore, when the distance L was 0.1 mm or more and 70 mm or less, the wafer oven temperature was kept below 5.0°C. In particular, when the distance L was 1 mm or more and 15 mm or less, the wafer oven temperature was kept below 2.5°C.

[0090] Test Example 3 In Test Example 3, the influence of the distance L from the lower surface 20L of the mounting plate 20 to the upper surface 3U of the first reflector 3 on the power consumption Q and the wafer range was investigated by simulation when the material of the first reflector 3 was aluminum oxide. The thickness of the first reflector 3 was 3 mm.

[0091] Sample No. 3-1 is a reference sample having the same configuration as Sample No. 1-1 of Test Example 1, i.e., not including the first reflector 3. The only difference between Samples No. 3-2 to 3-22 is the distance L between the upper surface 3U of the first reflector 3 made of aluminum oxide and the lower surface 20L of the mounting plate 20. The measurement results are shown in Table 3.

[0092]

[0093] As shown in Table 3, it was found that a reduction in power consumption was achieved when the distance L was 0.1 mm or more and 60 mm or less. When the distance L was 0.1 mm or more and 40 mm or less, the power consumption was reduced to 95% or less of the reference sample. When the distance L was 0.1 mm or more and 30 mm or less, the power consumption was reduced to 93% or less of the reference sample. When the distance L was 1 mm or more and 25 mm or less, the power consumption was reduced to 92% or less of the reference sample. When the distance L was 1 mm or more and 15 mm or less, the power consumption was reduced to 91% or less of the reference sample. In particular, it was found that a reduction in power consumption was achieved when the distance L was 3 mm or more and 6 mm or less. Furthermore, a reduction in wafer temperature was achieved when the distance L was 0.1 mm or more and 60 mm or less. When the distance L was 1 mm or more and 30 mm or less, the wafer temperature was kept to 5.0°C or less. In particular, when the distance L was 5 mm or more and 7 mm or less, the wafer temperature was kept to 4.0°C or less.

[0094] Test Example 4 In Test Example 4, the influence of the distance L from the lower surface 20L of the mounting plate 20 to the upper surface 3U of the first reflector 3 on the power consumption and the wafer range was investigated by simulation when the material of the first reflector 3 was aluminum nitride. The thickness of the first reflector 3 was 3 mm.

[0095] Sample No. 4-1 is a reference sample having the same configuration as Sample No. 1-1 of Test Example 1, i.e., including a first reflecting plate 3. The only difference between Samples No. 4-2 to 4-22 is the distance L between the upper surface 3U of the first reflecting plate 3 made of aluminum nitride and the lower surface 20L of the mounting plate 20.

[0096]

[0097] As shown in Table 4, it was found that a reduction in power consumption was achieved when the distance L was 0.1 mm or more and 60 mm or less. When the distance L was 0.1 mm or more and 40 mm or less, the power consumption was reduced to 96% or less of the reference sample. When the distance L was 0.1 mm or more and 30 mm or less, the power consumption was reduced to 95% or less of the reference sample. When the distance L was 1 mm or more and 20 mm or less, the power consumption was reduced to 94% or less of the reference sample. In particular, when the distance L was 2 mm or more and 10 mm or less, the power consumption was reduced to 93% or less of the reference sample. Furthermore, when the distance L was 0.1 mm or more and 60 mm or less, a reduction in wafer temperature was achieved. When the distance L was 1 mm or more and 20 mm or less, the wafer temperature was kept to 5.0°C or less. In particular, when the distance L was 2 mm or more and 15 mm or less, the wafer temperature was kept to 4.7°C or less.

[0098] Test Example 5 In Test Example 5, the power consumption and wafer range of a semiconductor processing apparatus 1 equipped with a second reflector 4 or a third reflector 5 in addition to a first reflector 3 were determined by simulation. The chamber 9 in this example was made of an aluminum alloy whose inner circumferential surface was surface-treated, and the emissivity of the inner circumferential surface was 0.2.

[0099] The outer diameter of the mounting plate 20 in each sample of Test Example 5 was 340 mm, and the thickness of the mounting plate 20 was 19 mm. In other words, the size of the mounting plate 20 in Test Example 5 was slightly different from that of Test Examples 1 to 3. Sample No. 5-1 was configured to include a first reflector 3 but not a second reflector 4 or a third reflector 5. Samples No. 5-2 to 5-5 were configured to include a first reflector 3, a second reflector 4, or a third reflector 5. The first reflector 3 in each sample was made of aluminum nitride, and the distance L was 5 mm. The second reflector 4 and the third reflector 5 were made of aluminum alloy with International Registered Alloy Number A5052 or aluminum oxide. The emissivity of A5052 at 550°C was 0.1. The thickness of the second reflector 4 and the third reflector 5 was 2 mm.

[0100] In Test Example 5, the power consumption of each sample was calculated relative to the power consumption of Sample No. 5-1 in Test Example 1, which was set at 100%. The results are shown in Table 5.

[0101]

[0102] A comparison of Samples No. 5-1 to 5-3 in Table 5 reveals that adding a second reflector 4 or a third reflector 5 having an emissivity of less than 0.15 to the semiconductor processing apparatus 1 can reduce the amount of power consumed by the semiconductor processing apparatus 1. On the other hand, as shown in Samples No. 5-4 and 5-5, it was found that when the emissivity of the second reflector 4 or the third reflector 5 is 0.15 or higher, the amount of power consumed actually increases.

[0103] Although not shown in Table 5, it is expected that the power consumption of the semiconductor processing apparatus 1 can be further reduced by adding both the second reflector 4 and the third reflector 5 in addition to the first reflector 3.

[0104] <Demonstration Test> In the demonstration test, a semiconductor processing apparatus 1 was fabricated in which a first reflecting plate 3 made of aluminum nitride and having a thickness of 3 mm was positioned 5 mm away from the lower surface 20L, and the amount of power consumed by the semiconductor processing apparatus 1 was measured when the temperature of the mounting plate 20 was raised to 500° C. As a result, it was confirmed that the amount of power consumed by the semiconductor processing apparatus 1 equipped with the first reflecting plate 3 was approximately 10% lower than that of a semiconductor processing apparatus without the first reflecting plate 3.

[0105] REFERENCE SIGNS LIST 1 semiconductor processing apparatus 2 wafer holder 20 mounting plate 20L lower surface 20U upper surface 21 heater 21R resistance heating element 25 support 25L lower end 25U upper end 3 first reflector 3L lower surface 3U upper surface 30 spacer 31 fixing member 35 side wall 4 second reflector 5 third reflector 9 chamber 9L lower chamber 9U upper chamber 90 inner bottom surface 91 inner side surface 95 shower head L distance

Claims

1. A wafer holder arranged within a chamber, comprising: a mounting plate having an upper surface on which a wafer is placed and a lower surface opposite the upper surface; a support body supporting the lower surface; and a first reflector arranged at a position below the lower surface, wherein the distance L between the lower surface and the first reflector is 0.1 mm or more and 60 mm or less, and the emissivity of the first reflector is equal to or less than the emissivity of the mounting plate.

2. The wafer holder according to claim 1, wherein said first reflector is made of either stainless steel, aluminum oxide, or aluminum nitride.

3. The wafer holder according to claim 2, wherein the first reflector is made of stainless steel, and the distance L is 0.1 mm or more and 50 mm or less.

4. The wafer holder according to claim 2, wherein the first reflector is made of aluminum oxide, and the distance L is 0.1 mm or more and 40 mm or less.

5. The wafer holder according to claim 2, wherein the first reflector is made of aluminum nitride, and the distance L is 0.1 mm or more and 40 mm or less.

6. A wafer holding table as described in any one of claims 1 to 5, further comprising a spacer disposed between said underside and said first reflecting plate, said first reflecting plate being fixed to said underside so as to ensure said distance L by said spacer.

7. A semiconductor processing apparatus comprising: a wafer holder according to any one of claims 1 to 6; and a chamber in which the wafer holder is disposed.

8. The semiconductor processing apparatus according to claim 7, further comprising a second reflector disposed inside the chamber, the chamber having an inner bottom surface facing a lower surface of the first reflector, the second reflector being disposed on the inner bottom surface, and the emissivity of the second reflector being less than the emissivity of the inner bottom surface.

9. The semiconductor processing apparatus according to claim 7 or claim 8, further comprising a third reflector disposed inside the chamber, the chamber having an inner surface facing an outer circumferential surface of the support, the third reflector being disposed on the inner surface, and the emissivity of the third reflector being less than the emissivity of the inner surface.

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