Substrate processing equipment

Abstract

The objective is to provide a substrate processing apparatus that can suppress the discharge of liquid from the periphery of the substrate before freezing. [Solution] The substrate processing apparatus according to the embodiment comprises: a rotatable mounting table provided with a plurality of support parts capable of supporting a substrate having a rectangular planar shape so as to form a space between the substrate and the mounting table; a cooling unit capable of supplying cooling gas to the space between the mounting table and the substrate; a liquid supply unit capable of supplying liquid to the surface of the substrate opposite to the surface on the mounting table side; and a plate having a plate-like shape that surrounds the periphery of the substrate and extends to extend the periphery of the substrate so as to form a space through which the cooling gas flows between the mounting table and the plate, wherein the plurality of support parts are provided below the plate and in a position that can contact the edge of the back surface of the substrate.

Description

Technical Field

[0001] Embodiments of the present invention relate to a substrate processing apparatus.

Background Art

[0002] On the surfaces of substrates such as imprint templates, photolithography masks, and semiconductor wafers, fine concavo-convex portions are formed. As a method for removing contaminants such as particles adhering to the surfaces of such substrates, a freeze cleaning method has been proposed.

[0003] In the freeze cleaning method, first, a liquid such as pure water is supplied to the surface of the substrate to form a liquid film. Next, a cooling gas is supplied to the surface side of the substrate to freeze the liquid film. When the liquid film freezes to form a frozen film, contaminants are incorporated into the frozen film, so that the contaminants are separated from the surface of the substrate. Next, a liquid such as pure water is supplied to the frozen film to melt the frozen film, and the contaminants are removed from the surface of the substrate together with the liquid. According to the freeze cleaning method, it is possible to suppress damage to the fine concavo-convex portions formed on the surface of the substrate.

[0004] In freeze cleaning, freezing is usually performed while rotating. Therefore, the peripheral region of the substrate is easily affected by the outside air, and cooling is suppressed. Therefore, development of a substrate processing apparatus capable of improving the cooling efficiency of the peripheral region of the substrate has been desired.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is to provide a substrate processing apparatus capable of improving the cooling efficiency of the peripheral region of the substrate. [Means for solving the problem]

[0007] The substrate processing apparatus according to this embodiment includes: a rotatable mounting table provided with a plurality of support parts capable of supporting a substrate having a rectangular planar shape so as to form a space between the substrate and the mounting table; a cooling unit capable of supplying cooling gas to the space between the mounting table and the substrate; a liquid supply unit capable of supplying liquid to the surface of the substrate opposite to the surface facing the mounting table; and a plate that is plate-shaped and surrounds the periphery of the substrate, extending to extend the periphery of the substrate, so as to form a space between the mounting table and the mounting table through which the cooling gas flows, wherein the plurality of support parts are provided below the plate and in a position to contact the edge of the back surface of the substrate. [Effects of the Invention]

[0008] According to embodiments of the present invention, a substrate processing apparatus is provided that can improve the cooling efficiency of the peripheral region of the substrate. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the substrate processing apparatus according to this embodiment. [Figure 2] This is a schematic diagram of the mounting section in the direction of line AA in Figure 1. [Figure 3] This is a schematic cross-sectional view of the mounting section in the direction of line BB in Figure 2. [Figure 4] (a) and (b) are schematic cross-sectional views illustrating the liquid-repellent portion. [Figure 5] This is a timing chart illustrating the operation of a substrate processing device. [Figure 6] This is a schematic diagram illustrating a mounting platform related to a comparative example. [Figure 7] (a) and (b) are schematic cross-sectional views illustrating the liquid-repellent portion. [Figure 8] This is a schematic plan view illustrating a plate having multiple small pieces. [Figure 9]This is a schematic cross-sectional view illustrating a plate having multiple small pieces. [Figure 10] This is a schematic diagram illustrating a substrate processing apparatus according to another embodiment. [Modes for carrying out the invention]

[0010] The embodiments will be illustrated below with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed descriptions will be omitted as appropriate. The substrate 100 exemplified below can be, for example, a semiconductor wafer, an imprint template, a photolithography mask, a plate-like body used in MEMS (Micro Electro Mechanical Systems), or a substrate for a flat panel display. Furthermore, in the following section, we will describe the case where the substrate 100 is a photolithography mask as an example. When the substrate 100 is a photolithography mask, the planar shape of the substrate 100 can be approximately rectangular. One surface of the substrate 100 has a pattern of raised and recessed areas which is the pattern of the mask.

[0011] Figure 1 is a schematic diagram illustrating a substrate processing apparatus 1 according to this embodiment. Figure 2 is a schematic diagram of the mounting section 2 in the direction of line AA in Figure 1. Figure 3 is a schematic cross-sectional view of the mounting section 2 in the direction of line BB in Figure 2. Figure 4 is a schematic cross-sectional view illustrating the liquid-repellent portion 2d2.

[0012] As shown in Figure 1, the substrate processing apparatus 1 is equipped with a mounting section 2, a cooling section 3, a first liquid supply section 4, a second liquid supply section 5, a housing 6, a blower section 7, a measuring section 8, a control section 9, and an exhaust section 11.

[0013] The mounting unit 2 includes a mounting base 2a, a rotating shaft 2b, a drive unit 2c, and a plate 2d. The mounting base 2a is rotatably installed inside the housing 6. The mounting base 2a has a plate-like shape. is. On one main surface of the mounting table 2a, a plurality of support portions 2a1 for supporting the substrate 100 are provided. When the substrate 100 is supported by the plurality of support portions 2a1, the surface 100b (the surface on the side where the concavo-convex portions are formed) of the substrate 100 faces the side opposite to the mounting table 2a side.

[0014] The edges of the back surface 100a of the substrate 100 contact the plurality of support portions 2a1. The portion of the support portion 2a1 that contacts the edge of the back surface 100a of the substrate 100 can be a tapered surface or an inclined surface.

[0015] Also, a hole 2aa penetrating in the thickness direction of the mounting table 2a is provided in the central portion of the mounting table 2a.

[0016] One end of the rotating shaft 2b is fitted into the hole 2aa of the mounting table 2a. The other end of the rotating shaft 2b is provided outside the housing 6. The rotating shaft 2b is connected to the driving portion 2c outside the housing 6.

[0017] The rotating shaft 2b has a cylindrical shape. A blowing portion 2b1 is provided at the end of the rotating shaft 2b on the mounting table 2a side. The blowing portion 2b1 opens to the surface of the mounting table 2a where the plurality of support portions 2a1 are provided. The end on the opening side of the blowing portion 2b1 is connected to the inner wall of the hole 2aa. The opening of the blowing portion 2b1 faces the back surface 100a of the substrate 100 supported by the mounting table 2a.

[0018] The blowing portion 2b1 has a shape in which the cross-sectional area increases as it approaches the mounting table 2a side (opening side). Therefore, the hole inside the blowing portion 2b1 has a cross-sectional area that increases as it approaches the mounting table 2a side (opening side). Although the case where the blowing portion 2b1 is provided at the tip of the rotating shaft 2b is illustrated, the blowing portion 2b1 can also be provided at the tip of the cooling nozzle 3d. Also, the hole 2aa of the mounting table 2a can be used as the blowing portion 2b1.

[0019] By providing the blowing outlet 2b1, the released cooling gas 3a1 can be supplied to a wider area of ​​the back surface 100a of the substrate 100. Furthermore, the release rate of the cooling gas 3a1 can be reduced. Therefore, partial cooling of the substrate 100 or excessive cooling of the substrate 100 can be prevented. As a result, it becomes easier to induce the supercooled state of the liquid 101 described later.

[0020] A cooling nozzle 3d is attached to the end of the rotating shaft 2b opposite to the mounting base 2a. A rotating shaft seal (not shown) is provided between the end of the rotating shaft 2b opposite to the mounting base 2a and the cooling nozzle 3d. Therefore, the end of the rotating shaft 2b opposite to the mounting base 2a is sealed to be airtight.

[0021] The drive unit 2c is located outside the housing 6. The drive unit 2c is connected to the rotating shaft 2b. The drive unit 2c may have a rotating device such as a motor. The rotational force of the drive unit 2c is transmitted to the mounting base 2a via the rotating shaft 2b. Therefore, the drive unit 2c can rotate the mounting base 2a, and by extension, the substrate 100 supported on the mounting base 2a.

[0022] Furthermore, the drive unit 2c can not only start and stop rotation, but also change the rotational speed. The drive unit 2c can be equipped with a control motor, such as a servo motor.

[0023] As shown in Figures 2 to 4, the plate 2d is plate-shaped and is provided on the outside of the substrate 100. The plate 2d surrounds the periphery of the substrate 100. The plate 2d can be provided on the mounting base 2a via, for example, a spacer 2d1.

[0024] The thickness of plate 2d can be approximately the same as or less than the thickness of substrate 100. Furthermore, as shown in Figure 2, the external dimensions of plate 2d can be larger than the circumscribed circle 100d containing the corners of substrate 100. While the outline of plate 2d shown in Figure 2 is a circle, it may also be a polygon such as a quadrilateral or hexagon.

[0025] The side of plate 2d opposite to the mounting base 2a is called the front surface 2db, and the side of plate 2d facing the mounting base 2a is called the back surface 2da. It is preferable that the distance between the surface 2db of plate 2d and the mounting base 2a be the same as, or about 0.1 mm smaller than, the distance between the surface 100b of substrate 100 and the mounting base 2a. In this way, it is possible to suppress the plate 2d from becoming an obstacle when the liquid 101 and the frozen liquid 101 are discharged from the surface 100b of substrate 100 during the thawing process described later.

[0026] It is preferable that the distance between the back surface 2da of the plate 2d and the mounting base 2a be the same as the distance between the back surface 100a of the substrate 100 and the mounting base 2a, or about 0.1 mm greater. This prevents turbulence in the flow of cooling gas 3a1 in the space between the mounting base 2a and the back surface 100a of the substrate 100 during the preliminary and cooling processes described later. In addition, grooves (not shown) are provided on the back surface 2da of the plate 2d at positions corresponding to a plurality of support parts 2a1. These grooves prevent contact with the support parts 2a1.

[0027] Furthermore, in the preliminary, cooling, and thawing processes described later, if the liquid 101 supplied to the surface 100b of the substrate 100 leaks from the side surface 2dc of the plate 2d on the substrate 100 side to the mounting base 2a side, the leaked liquid 101 may freeze on the mounting base 2a or the back surface 100a of the substrate 100. If the leaked liquid 101 freezes on the mounting base 2a or the back surface 100a of the substrate 100, the flow of the cooling gas 3a1 may be disturbed.

[0028] Therefore, it is preferable that the plate 2d be in contact with the side surface of the substrate 100. If the plate 2d is in contact with the side surface of the substrate 100, it is possible to suppress the leakage of the liquid 101 supplied to the surface 100b of the substrate 100 from the side surface 2dc of the plate 2d to the mounting base 2a side.

[0029] Furthermore, it is preferable that the thermal conductivity of plate 2d be as close as possible to that of substrate 100. In this way, plate 2d can be considered an extension of substrate 100 during heat conduction. As will be described later, external heat easily enters the peripheral region of substrate 100, but if plate 2d can be considered an extension of substrate 100, the peripheral region of substrate 100 can be separated from the external atmosphere, making it difficult for external heat to enter the peripheral region of substrate 100. Therefore, in the preliminary and cooling processes described later, it becomes easy to make the temperature of the peripheral region of substrate 100 and the temperature of the central region of substrate 100 approximately the same. In this case, it is even more preferable that the thermal conductivity of plate 2d be the same as that of substrate 100.

[0030] Furthermore, it is preferable that the coefficient of thermal expansion of plate 2d be as close as possible to that of substrate 100. In this way, during thermal expansion or contraction, plate 2d can be considered an extension of substrate 100. Therefore, in the preliminary process, cooling process, thawing process, etc., described later, it is possible to suppress the formation of gaps between the side surface 2dc of plate 2d and the side surface of substrate 100, and to prevent forces from being applied to plate 2d and substrate 100.

[0031] Considering thermal conductivity and coefficient of linear expansion, it is preferable that the material of plate 2d be the same as the main material of substrate 100. For example, if substrate 100 is a photolithography mask, the material of plate 2d can be quartz.

[0032] As described later, at least the surface 2db of the plate 2d is provided with a liquid-repellent portion 2d2 (see Figure 4(a)). The liquid-repellent portion 2d2 has the property of repelling liquid 101 more easily than the substrate 100 (liquid repellency). The liquid-repellent portion 2d2 may, for example, be a film-like material having functional groups such as saturated fluoroalkyl groups such as trifluoromethyl groups, fluorosilyl groups, alkylsilyl groups, and long-chain alkyl groups. For example, the liquid-repellent portion 2d2 can be formed by coating the surface of the plate 2d with a fluororesin.

[0033] Furthermore, the liquid-repellent portion 2d2 can also be formed by processing the surface of the plate 2d to create a fractal structure. The fractal structure can be formed, for example, by etching the surface of the plate 2d using plasma or a corrosive liquid. Alternatively, the surface of a film containing the aforementioned functional group material can also be made into a fractal structure. In other words, the liquid-repellent portion 2d2 can have a fractal structure.

[0034] Next, we will return to Figure 1 and describe the other components provided in the substrate processing apparatus 1. As shown in Figure 1, the cooling unit 3 supplies cooling gas 3a1 to the space between the mounting base 2a and the back surface 100a of the substrate 100. The cooling unit 3 includes a cooling liquid section 3a, a filter 3b, a flow rate control unit 3c, and a cooling nozzle 3d. The cooling liquid section 3a, the filter 3b, and the flow rate control unit 3c are located outside the housing 6.

[0035] The coolant section 3a stores the coolant and generates the cooling gas 3a1. The coolant is a liquefied form of the cooling gas 3a1. The cooling gas 3a1 is not particularly limited as long as it is a gas that does not react easily with the material of the substrate 100. The cooling gas 3a1 can be an inert gas such as nitrogen gas, helium gas, or argon gas.

[0036] The coolant section 3a includes a tank for storing coolant and a vaporization section for vaporizing the coolant stored in the tank. The tank is equipped with a cooling device for maintaining the temperature of the coolant. The vaporization section raises the temperature of the coolant to generate cooling gas 3a1 from the coolant. The vaporization section can, for example, utilize the ambient temperature or use heating with a heat transfer medium. The temperature of the cooling gas 3a1 should be below the freezing point of the liquid 101.

[0037] In the example given, the coolant section 3a generates cooling gas 3a1 by vaporizing the coolant stored in the tank. However, it is also possible to cool nitrogen gas or the like using a chiller to produce cooling gas 3a1. This would simplify the coolant section.

[0038] Filter 3b is connected to the coolant section 3a via piping. Filter 3b prevents contaminants such as particles contained in the coolant from flowing out to the substrate 100 side.

[0039] The flow control unit 3c is connected to the filter 3b via piping. The flow control unit 3c controls the flow rate of the cooling gas 3a1. The flow control unit 3c can be, for example, an MFC (Mass Flow Controller). Alternatively, the flow control unit 3c may indirectly control the flow rate of the cooling gas 3a1 by controlling the supply pressure of the cooling gas 3a1. In this case, the flow control unit 3c can be, for example, an APC (Auto Pressure Controller).

[0040] In the coolant section 3a, the temperature of the cooling gas 3a1 generated from the coolant is approximately at a predetermined temperature. Therefore, the flow rate control unit 3c can control the flow rate of the cooling gas 3a1, thereby controlling the temperature of the substrate 100 and, consequently, the temperature of the liquid 101 on the surface 100b of the substrate 100. In this case, by controlling the flow rate of the cooling gas 3a1 with the flow rate control unit 3c, a supercooled state of the liquid 101 can be created in the supercooling process described later.

[0041] One end of the cooling nozzle 3d is connected to the flow control unit 3c. The other end of the cooling nozzle 3d is located inside the rotating shaft 2b. The other end of the cooling nozzle 3d is located near the end of the blowing section 2b1 that is on the flow control unit 3c side.

[0042] The cooling nozzle 3d is cylindrical in shape. The cooling nozzle 3d supplies cooling gas 3a1, whose flow rate is controlled by the flow control unit 3c, to the substrate 100. The cooling gas 3a1 released from the cooling nozzle 3d is supplied directly to the back surface 100a of the substrate 100 via the blowout section 2b1.

[0043] The first liquid supply unit 4 supplies liquid 101 to the surface 100b of the substrate 100. In the freezing process described later, when liquid 101 changes from liquid to solid (liquid-solid phase change), its volume changes, generating a pressure wave. This pressure wave is thought to separate contaminants adhering to the surface 100b of the substrate 100. Therefore, there are no particular limitations on the liquid 101 as long as it does not react easily with the material of the substrate 100.

[0044] Furthermore, if liquid 101 is a liquid whose volume increases when frozen, it is conceivable that contaminants adhering to the surface of substrate 100 can be separated by utilizing the physical force associated with the volume increase. For this reason, it is preferable that liquid 101 is a liquid that does not react easily with the material of substrate 100 and whose volume increases when frozen. For example, liquid 101 can be water (e.g., pure water or ultrapure water) or a liquid whose main component is water.

[0045] When using a liquid primarily composed of water, if the amount of components other than water becomes too large, it becomes difficult to utilize the physical forces associated with the increase in volume, which may reduce the rate of contaminant removal. Therefore, it is preferable that the concentration of components other than water be between 5 wt% and 30 wt%.

[0046] Furthermore, a gas can be dissolved in liquid 101. The gas can be, for example, carbon dioxide, ozone, or hydrogen gas.

[0047] The first liquid supply unit 4 includes a liquid storage unit 4a, a supply unit 4b, a flow rate control unit 4c, and a liquid nozzle 4d. The liquid storage unit 4a, the supply unit 4b, and the flow rate control unit 4c are located outside the housing 6.

[0048] The liquid storage section 4a stores the aforementioned liquid 101. The supply unit 4b is connected to the liquid storage unit 4a via piping. The supply unit 4b supplies the liquid 101 stored in the liquid storage unit 4a towards the liquid nozzle 4d. The supply unit 4b can be, for example, a pump resistant to the liquid 101. Although the example given is that the supply unit 4b is a pump, the supply unit 4b is not limited to a pump. For example, the supply unit 4b may supply gas into the liquid storage unit 4a and pressurize the liquid 101 stored in the liquid storage unit 4a.

[0049] The flow control unit 4c is connected to the supply unit 4b via piping. The flow control unit 4c controls the flow rate of the liquid 101 supplied by the supply unit 4b. The flow control unit 4c can be, for example, a flow control valve. The flow control unit 4c can also start and stop the supply of the liquid 101.

[0050] The liquid nozzle 4d is located inside the housing 6. The liquid nozzle 4d is cylindrical in shape. One end of the liquid nozzle 4d is connected to the flow control unit 4c via piping. The other end of the liquid nozzle 4d faces the surface 100b of the substrate 100 which is placed on the mounting base 2a. Therefore, the liquid 101 discharged from the liquid nozzle 4d is supplied to the surface 100b of the substrate 100.

[0051] Furthermore, the other end of the liquid nozzle 4d (the outlet for the liquid 101) is located approximately in the center of the surface 100b of the substrate 100. The liquid 101 discharged from the liquid nozzle 4d spreads from approximately in the center of the surface 100b of the substrate 100, forming a liquid film with approximately constant thickness on the surface 100b of the substrate 100.

[0052] The second liquid supply unit 5 supplies liquid 102 to the surface 100b of the substrate 100. The second liquid supply unit 5 includes a liquid storage unit 5a, a supply unit 5b, a flow rate control unit 5c, and a liquid nozzle 4d.

[0053] Liquid 102 can be used in the thawing process described later. Therefore, there are no particular limitations on liquid 102 as long as it does not react easily with the material of the substrate 100 and does not easily remain on the surface 100b of the substrate 100 in the drying process described later. Liquid 102 can be, for example, water (e.g., pure water or ultrapure water) or a liquid whose main component is water.

[0054] The liquid storage unit 5a can be the same as the liquid storage unit 4a described above. The supply unit 5b can be the same as the supply unit 4b described above. The flow rate control unit 5c can be the same as the flow rate control unit 4c described above.

[0055] Furthermore, if liquid 102 and liquid 101 are the same, the second liquid supply unit 5 can be omitted. Also, although the example given shows the case where the liquid nozzle 4d is used for both, it is also possible to provide separate liquid nozzles for dispensing liquid 101 and liquid nozzles for dispensing liquid 102.

[0056] Furthermore, the temperature of liquid 102 can be higher than the freezing point of liquid 101. Alternatively, the temperature of liquid 102 can be set to a temperature that can thaw the frozen liquid 101. For example, the temperature of liquid 102 can be around room temperature (20°C).

[0057] If the second liquid supply unit 5 is omitted, the temperature of the liquid 101 can be set to a temperature higher than the freezing point of the liquid 101. Alternatively, the temperature of the liquid 101 can be set to a temperature at which frozen liquid 101 can be thawed. For example, the temperature of the liquid 101 can be set to room temperature (20°C).

[0058] The housing 6 is box-shaped. A cover 6a is provided inside the housing 6. The cover 6a receives the liquids 101 and 102 supplied to the substrate 100 and discharged to the outside of the substrate 100 as the substrate 100 rotates. The cover 6a is cylindrical. The end of the cover 6a opposite to the mounting base 2a (near the upper end of the cover 6a) is bent towards the center of the cover 6a. Therefore, it is possible to easily capture the liquids 101 and 102 that splash upwards from the substrate 100.

[0059] Furthermore, a partition plate 6b is provided inside the housing 6. The partition plate 6b is provided between the outer surface of the cover 6a and the inner surface of the housing 6.

[0060] Multiple outlets 6c are provided on the bottom side of the housing 6. In Figure 1, there are two outlets 6c. Used cooling gas 3a1, air 7a, liquid 101, and liquid 102 are discharged to the outside of the housing 6 through the outlets 6c. An exhaust pipe 6c1 is connected to the outlets 6c, and an exhaust unit (pump) 11 for exhausting used cooling gas 3a1 and air 7a is connected to the exhaust pipe 6c1. In addition, an outlet pipe 6c2 for discharging liquids 101 and 102 is connected to the outlets 6c.

[0061] The exhaust port 6c is located below the substrate 100. Therefore, the cooling gas 3a1 is exhausted from the exhaust port 6c, creating a downflow. As a result, the scattering of particles can be prevented.

[0062] In a plan view, the multiple exhaust ports 6c are arranged symmetrically with respect to the center of the housing 6. This arrangement ensures that the exhaust direction of the cooling gas 3a1 is symmetrical with respect to the center of the housing 6. Symmetrical exhaust direction of the cooling gas 3a1 ensures smooth exhaust of the cooling gas 3a1.

[0063] The air blower unit 7 is located on the ceiling surface of the housing 6. Alternatively, the air blower unit 7 may be located on the side of the housing 6, as long as it is on the ceiling side. The air blower unit 7 can be equipped with a fan or other blower and a filter. The filter can be, for example, a HEPA filter (High Efficiency Particulate Air Filter).

[0064] The air blower 7 supplies air 7a (outside air) to the space between the partition plate 6b and the ceiling of the housing 6. As a result, the pressure in the space between the partition plate 6b and the ceiling of the housing 6 becomes higher than the external pressure. Consequently, it becomes easier to guide the air 7a supplied by the air blower 7 to the exhaust port 6c. In addition, it is possible to suppress the entry of contaminants such as particles into the interior of the housing 6 from the exhaust port 6c.

[0065] The control unit 9 controls the operation of each element provided in the substrate processing apparatus 1. The control unit 9 may have, for example, an arithmetic element such as a CPU (Central Processing Unit) and a memory element such as a semiconductor memory. The control unit 9 may be, for example, a computer. The memory element can store a control program that controls the operation of each element provided in the substrate processing apparatus 1. The arithmetic element controls the operation of each element provided in the substrate processing apparatus 1 using the control program stored in the memory element, data input by the operator, etc.

[0066] Next, we will illustrate the operation of the substrate processing apparatus 1. Figure 5 is a timing chart illustrating the operation of the substrate processing apparatus 1. Figure 5 shows the case where substrate 100 is a 6025 quartz (Qz) substrate (152 mm × 152 mm × 6.35 mm), and liquids 101 and 102 are pure water.

[0067] First, the circuit board 100 is loaded into the enclosure 6 through an inlet / outlet (not shown) of the enclosure 6. The loaded circuit board 100 is then placed and supported on multiple support parts 2a1 of the mounting base 2a.

[0068] After the substrate 100 is placed and supported on the mounting table 2a, a freeze-cleaning process is performed, which includes a preliminary process, a liquid film formation process, a cooling process (supercooling process + freezing process), a thawing process, and a drying process, as shown in Figure 5.

[0069] First, a preliminary process is performed as shown in Figure 5. In the preliminary process, the control unit 9 controls the supply unit 4b and the flow rate control unit 4c to supply liquid 101 at a predetermined flow rate to the surface 100b of the substrate 100. The control unit 9 also controls the flow rate control unit 3c to supply cooling gas 3a1 at a predetermined flow rate to the back surface 100a of the substrate 100. The control unit 9 also controls the drive unit 2c to rotate the substrate 100 at a predetermined rotational speed (second rotational speed). Therefore, the liquid 101 is continuously flowing onto the rotating substrate 100 and plate 2d.

[0070] Here, when the atmosphere inside the housing 6 is cooled by the supply of cooling gas 3a1 from the cooling unit 3, frost containing dust from the air may adhere to the substrate 100, potentially causing contamination. In the preliminary process, liquid 101 is continuously supplied to the surface 100b of the substrate 100, so that the substrate 100 is cooled uniformly while preventing frost from adhering to the surface 100b of the substrate 100.

[0071] For example, in the case illustrated in Figure 5, the rotation speed of the substrate 100 can be set to approximately 50 rpm to 500 rpm as the first rotation speed. The flow rate of the liquid 101 can be set to approximately 0.1 L / min to 1 L / min. The flow rate of the cooling gas 3a1 can be set to approximately 40 NL / min to 200 NL / min, and the processing time for the preliminary step can be set to approximately 1800 seconds. The processing time for the preliminary step should be the time required for the in-plane temperature of the substrate 100 to become approximately uniform. These conditions can be determined in advance by conducting experiments or simulations.

[0072] In the preliminary process, the temperature of the liquid 101 on the surface 100b of the substrate 100 is approximately the same as the temperature of the supplied liquid 101, because the liquid 101 is continuously flowing. For example, if the temperature of the supplied liquid 101 is around room temperature (20°C), the temperature of the liquid 101 present on the surface 100b of the substrate 100 (hereinafter referred to as the liquid film) will be around room temperature (20°C).

[0073] Next, as shown in Figure 5, the liquid film formation process is performed. In the liquid film formation process, the supply of liquid 101 that was supplied in the preliminary process is stopped. As the rotation of the substrate 100 and plate 2d is maintained, the liquid 101 on the surface 100b of the substrate 100 is discharged. Then, the rotation speed of the substrate 100 is reduced to a first rotation speed that is slower than the second rotation speed. The first rotation speed can be, for example, in the range of 0 to 50 rpm. After the rotation speed of the substrate 100 is set to the first rotation speed, a predetermined amount of liquid 101 is supplied to the substrate 100 to form a liquid film. The supply of cooling gas 3a1 is maintained.

[0074] The thickness of the liquid film formed during the liquid film formation process (the thickness of the liquid film during the supercooling process) can be approximately 200 to 1300 μm. For example, the control unit 9 controls the supply amount of liquid 101 to make the thickness of the liquid film on the surface 100b of the substrate 100 approximately 200 to 1300 μm.

[0075] Next, as shown in Figure 5, a cooling process (supercooling process + freezing process) is performed. In this embodiment, the process from when the liquid 101 becomes supercooled until freezing begins is called the "supercooling process," and the process from when the supercooled liquid 101 becomes frozen until thawing begins in the thawing process is called the "freezing process."

[0076] If the cooling rate of the liquid 101 becomes too fast, the liquid 101 will not become supercooled and will freeze immediately. Therefore, the control unit 9 controls at least one of the flow rate of the cooling gas 3a1 and the rotation speed of the substrate 100 to ensure that the liquid 101 on the surface 100b of the substrate 100 becomes supercooled.

[0077] The conditions under which liquid 101 becomes supercooled are influenced by factors such as the size of the substrate 100, the viscosity of liquid 101, and the specific heat of the cooling gas 3a1. Therefore, it is preferable to determine the conditions under which liquid 101 becomes supercooled appropriately through experiments or simulations.

[0078] In the cooling process (supercooling process + freezing process), as illustrated in Figure 5, the flow rate and rotation speed of the cooling gas 3a1 are the same as those in the liquid film formation process. The cooling gas 3a1 continuously supplied to the back surface 100a of the substrate 100 causes the temperature of the liquid film on the substrate 100 to drop even further than the temperature of the liquid film in the liquid film formation process, resulting in a supercooled state.

[0079] In a supercooled state, freezing of liquid 101 begins due to factors such as the temperature of the liquid film, the presence of contaminants such as particles, and vibration. For example, if contaminants such as particles are present, freezing of liquid 101 begins when its temperature drops to around -20°C to -35°C.

[0080] When the supercooled liquid 101 begins to freeze, the process transitions from the supercooling step to the freezing step. In the freezing step, at least a portion of the liquid film on the surface 100b of the substrate 100 is frozen. This embodiment of the freezing and cleaning process describes the case where the liquid film completely freezes and becomes an ice film.

[0081] Next, the thawing process is performed as shown in Figure 5. Note that the example in Figure 5 is the case where liquid 101 and liquid 102 are the same liquid. Therefore, in Figure 5, it is labeled as liquid 101. In the thawing process, the control unit 9 controls the supply unit 4b and the flow rate control unit 4c to supply liquid 101 at a predetermined flow rate to the surface 100b of the substrate 100. If liquid 101 and liquid 102 are different, the control unit 9 controls the supply unit 5b and the flow rate control unit 5c to supply liquid 102 at a predetermined flow rate to the surface 100b of the substrate 100.

[0082] Furthermore, the control unit 9 controls the flow rate control unit 3c to stop the supply of cooling gas 3a1. This initiates the thawing of the ice film, which gradually turns into liquid 101. The control unit 9 also controls the drive unit 2c to increase the rotation speed of the substrate 100 to a third rotation speed, which is faster than the second rotation speed. As the substrate 100 rotates faster, the liquid 101 and any remaining ice film can be shaken off by centrifugal force. As a result, the liquid 101 and the remaining ice film can be discharged from the surface 100b of the substrate 100. At this time, any contaminants separated from the surface 100b of the substrate 100 are also discharged along with these.

[0083] Furthermore, there are no particular limitations on the amount of liquid 101 or liquid 102 supplied, as long as it can be thawed. Also, there are no particular limitations on the rotation speed of the substrate 100, as long as the liquid 101, unmelted ice film, and contaminants can be discharged.

[0084] Next, a drying process is performed as shown in Figure 5. During the drying process, the control unit 9 controls the supply unit 4b and the flow rate control unit 4c to stop the supply of liquid 101. If liquid 101 and liquid 102 are different liquids, the control unit 9 controls the supply unit 5b and the flow rate control unit 5c to stop the supply of liquid 102.

[0085] Furthermore, the control unit 9 controls the drive unit 2c to further increase the rotation speed of the substrate 100, increasing it to a fourth rotation speed that is faster than the third rotation speed. A faster rotation speed of the substrate 100 allows for faster drying of the substrate 100. Note that there are no particular limitations on the rotation speed of the substrate 100, as long as drying is possible. By doing so, the substrate 100 can be processed (contamination removed).

[0086] Figure 6 is a schematic diagram illustrating a mounting platform 202a related to a comparative example. As shown in Figure 6, one main surface of the mounting base 202a is provided with a plurality of support parts 2a1 for supporting the substrate 100. In addition, a hole 202aa is provided in the central part of the mounting base 202a that penetrates through the thickness direction of the mounting base 202a. However, while the aforementioned mounting base 2a was provided with a plate 2d, the mounting base 202a is not provided with a plate 2d.

[0087] Cooling gas 3a1 is supplied through the hole 202aa. The supplied cooling gas 3a1 flows through the space between the mounting base 202a and the back surface 100a of the substrate 100 and is discharged to the outside of the substrate 100. The substrate 100 is cooled as the cooling gas 3a1 absorbs heat from the substrate 100. On the other hand, the temperature of the cooling gas 3a1 rises as it absorbs heat from the substrate 100.

[0088] Since the flow resistance in the direction parallel to the surface of the mounting base 202a is almost the same, the cooling gas 3a1 flows almost radially from the holes 202aa, as shown in Figure 6. As the cooling gas 3a1 flows in almost one direction while removing heat from the substrate 100, the temperature of the cooling gas 3a1 increases towards the periphery of the substrate 100, and the cooling efficiency decreases. In addition, the peripheral region of the substrate 100 is adjacent to the external atmosphere not only in the direction perpendicular to the surface 100b of the substrate 100, but also in the direction parallel to the surface 100b of the substrate 100, so the amount of heat input from the outside increases. Therefore, the cooling of the peripheral region of the substrate 100 is suppressed.

[0089] Furthermore, as shown in Figure 6, the substrate 100 rotates around the hole 202aa. When the planar shape of the substrate 100 is rectangular, the opening in the space between the back surface 100a of the substrate 100 and the mounting base 202a moves along the inscribed circle 100c that contacts the edge of the substrate 100, and does not move in the external atmosphere, so there is little intrusion of outside air as the substrate 100 rotates. In contrast, the opening in the space outside the inscribed circle 100c, that is, near the corners of the rectangle, moves in the external atmosphere, so as the substrate 100 rotates, outside air can easily enter from the tangential direction of the inscribed circle 100c. Therefore, when the planar shape of the substrate 100 is rectangular, in addition to the cooling of the peripheral region of the substrate 100 being suppressed, the cooling near the corners of the substrate 100 is further suppressed.

[0090] As described above, the mounting base 2a according to this embodiment is provided with a plate 2d having a liquid-repellent portion 2d2 on at least its surface 2db. Furthermore, the plate 2d surrounds the periphery of the substrate 100 and can be considered an extension of the substrate 100. In other words, the peripheral region of the substrate 100 can be considered to have been extended to the peripheral region of the plate 2d. Therefore, the distance between the peripheral region of the substrate 100 and the external atmosphere in a direction parallel to the surface 100b of the substrate 100 can be increased. As a result, the amount of heat input from the outside to the peripheral region of the substrate 100 can be reduced, so that the peripheral region of the substrate 100 can be cooled effectively. In particular, when the planar shape is rectangular, the vicinity of the corners of the substrate is difficult to cool. By arranging the plate 2d, the vicinity of the corners of the rectangular substrate 100 is located inside the plate 2d and does not open to the outside. Therefore, the intrusion of outside air due to the rotation of the substrate 100 is reduced, which not only reduces the amount of heat input from the outside to the peripheral region of the substrate 100, but also reduces the amount of heat input from the outside to the cooling gas. As a result, even if the planar shape of the substrate 100 is rectangular, cooling near the corners can be performed effectively. Therefore, the substrate 100 can be cooled more uniformly in the preliminary process.

[0091] Furthermore, during the liquid film formation process, the liquid-repellent portion 2d2 of the plate 2d surrounds the substrate 100, thereby suppressing the flow of liquid 101 from the surface 100b of the substrate 100 to the plate 2d. This makes it easier to retain the liquid 101 supplied to the surface 100b of the substrate 100 on the surface 100b of the substrate 100. As a result, a thicker liquid film can be formed compared to the case without the plate 2d. Also, compared to the case where the liquid film is formed up to the surface 2db of the plate 2d, the amount of liquid 101 required to obtain the desired liquid film thickness can be reduced.

[0092] It is not necessary to provide a liquid-repellent portion 2d2 on the entire surface 2db of plate 2d in order to suppress the flow of liquid 101 from the surface b of substrate 100 to plate 2d. As shown in Figure 4(b), if the thickness of plate 2d is T (mm), and the distance between the side surface 2dc of plate 2d on the substrate 100 side and the end of the liquid-repellent portion 2d2 provided on the surface 2db of plate 2d on the opposite side from substrate 100 is L (mm), then the flow of liquid 101 from the surface b of substrate 100 to plate 2d can be suppressed as long as "L≧T".

[0093] Furthermore, in the liquid film formation process, the rotation of the substrate 100 is kept below a first rotational speed. The first rotational speed is a rotational speed at which variations in the liquid film due to centrifugal force do not occur. As a result, the amount of heat input from the outside to the peripheral region of the substrate 100 can be reduced, and a thick liquid film can be formed while suppressing variations in the liquid film.

[0094] Furthermore, in the substrate processing apparatus 1 according to this embodiment, cooling gas 3a1 is supplied to the back surface 100a of the substrate 100 to cool the liquid 101 supplied to the front surface 100b of the substrate 100. By supplying cooling gas 3a1 to the back surface 100a of the substrate 100, the liquid film can be cooled via the substrate 100. Since the substrate 100 is uniformly cooled in the preliminary step, the liquid film formed on the front surface 100b of the substrate 100 can be uniformly cooled. As a result, localized freezing of the liquid film can be suppressed. Therefore, the pressure between the uneven parts provided on the front surface 100b of the substrate 100 can be made uniform, and the collapse of the uneven parts can be suppressed. As described above, in the preliminary step, the amount of heat input from the outside to the peripheral region of the substrate 100 is suppressed by the plate 2d, so the substrate 100 can be cooled more uniformly. Therefore, localized freezing of the liquid film can be further suppressed.

[0095] Furthermore, since cooling progresses in the thickness direction from the back surface 100a of the substrate 100 toward the front surface 100b, even if a temperature gradient exists in the thickness direction of the liquid film, the temperature at the interface between the surface 100b of the substrate 100 and the liquid 101 can be kept as low as possible. Therefore, freezing of the liquid 101 begins from the interface side between the surface 100b of the substrate 100 and the liquid 101. Also, since the temperature of the liquid 101 near the interface can be kept as low as possible, the expansion of the frozen liquid 101 near the interface can be greatly increased. Therefore, contaminants adhering to the surface 100b of the substrate 100 can be efficiently separated.

[0096] As shown in Figure 7(a), the liquid-repellent portion 2d2 can also be provided on the surface 2db of the plate 2d and on the side surface 2dc of the plate 2d on the substrate 100 side. Due to manufacturing errors or other factors, unintended gaps may form between the side surface 2dc of plate 2d and the side surface of substrate 100. By providing a liquid-repellent portion 2d2 on the side surface 2dc of plate 2d facing substrate 100, even if an unintended gap forms between the side surface 2dc of plate 2d and the side surface of substrate 100, it is possible to suppress leakage of the liquid 101 supplied to the surface 100b of substrate 100 from the gap between the side surface 2dc of plate 2d and the side surface of substrate 100 towards the mounting base 2a. In particular, it is preferable that the liquid-repellent portion 2d2 provided on the side surface 2dc of plate 2d facing substrate 100 has elastic properties. For example, an elastic body coated with a liquid-repellent material can be attached to the side surface 2dc of plate 2d. Furthermore, as shown in Figure 7(b), the liquid-repellent portion 2d2 may be provided on the entire surface of the plate 2d.

[0097] Furthermore, as shown in Figure 8, plate 2d can be a composite of multiple small pieces 2dd to 2dg. Furthermore, as shown in Figure 9, the multiple small pieces 2dd to 2dg may be placed on a drive unit 2dg provided around the mounting base 2a, rather than on the mounting base 2a, and may be made movable.

[0098] Figure 10 is a schematic diagram illustrating a substrate processing apparatus 1a according to another embodiment. As shown in Figure 10, the substrate processing apparatus 1a is equipped with a mounting unit 2, a cooling unit 3, a first liquid supply unit 4, a second liquid supply unit 5, a housing 6, a blower unit 7, a measuring unit 8, a temperature measuring unit 8a, a gas supply unit 10, and a control unit 9.

[0099] The temperature measuring unit 8a measures the temperature of the space between the substrate 100 and the mounting base 2a. This temperature is approximately equal to the temperature of the mixed gas (a mixture of cooling gas 3a1 and gas 10d) flowing between the substrate 100 and the mounting base 2a. The temperature measuring unit 8a can be, for example, a radiation thermometer.

[0100] The gas supply unit 10 includes a gas storage unit 10a, a flow rate control unit 10b, and a connection unit 10c. The gas storage section 10a stores and supplies gas 10d. The gas storage section 10a can be a high-pressure cylinder containing gas 10d or factory piping. The flow control unit 10b controls the flow rate of gas 10d. The flow control unit 10b can be, for example, an MFC that directly controls the flow rate of gas 10d, or an APC that indirectly controls the flow rate of gas 10d by controlling the pressure.

[0101] The connection part 10c is connected to the rotating shaft 2b. The connection part 10c connects the space between the rotating shaft 2b and the cooling nozzle 3d to the flow control unit 10b. The connection part 10c can be, for example, a rotary joint.

[0102] The gas 10d is not particularly limited as long as it is a gas that does not react easily with the material of the substrate 100. For example, gas 10d can be an inert gas such as nitrogen gas, helium gas, or argon gas. In this case, gas 10d can be the same gas as the cooling gas 3a1. However, the temperature of gas 10d is higher than the temperature of cooling gas 3a1. The temperature of gas 10d can be, for example, room temperature.

[0103] If the cooling rate of liquid 101 becomes too fast, the liquid 101 will not reach a supercooled state and will freeze immediately. In other words, the supercooling process cannot be performed. In this case, the cooling rate of liquid 101 can be controlled by at least one of the flow rate of cooling gas 3a1 and the rotation speed of the substrate 100. However, the temperature of cooling gas 3a1 is kept almost constant by the temperature setting of the cooling unit that supplies the cooling gas 3a1. Therefore, it may be difficult to slow down the cooling rate of liquid 101 by adjusting the flow rate of cooling gas 3a1.

[0104] Furthermore, reducing the rotation speed of the substrate 100 increases the thickness of the liquid film, thus slowing down the cooling rate. However, since there is a limit to the thickness of the liquid film that can be maintained by surface tension, it may be difficult to slow down the cooling rate of the liquid 101 by reducing the rotation speed of the substrate 100.

[0105] Therefore, in this embodiment, the cooling rate of the liquid 101 can be slowed down by mixing gas 10d, which is at a higher temperature than the cooling gas 3a1, with the cooling gas 3a1. The cooling rate of the liquid 101 can be controlled by the flow rates of gas 10d and cooling gas 3a1, the mixing ratio of gas 10d and cooling gas 3a1, the temperature of gas 10d, and so on.

[0106] Furthermore, even if the measurement unit 8 detects the temperature of the liquid film and controls the flow rate of the cooling gas 3a1, there may be a difference between the temperature of the surface 100b side of the substrate 100 (temperature of the liquid film) and the temperature of the back surface 100a side of the substrate 100. Therefore, if the flow rate of the cooling gas 3a1 is controlled based solely on the temperature of the liquid film detected by the measurement unit 8, even if the temperature of the liquid film reaches the appropriate temperature, a difference may occur between the temperature of the liquid film and the temperature of the back surface 100a of the substrate 100, resulting in a large temperature gradient in the thickness direction of the substrate 100. A large temperature gradient in the thickness direction of the substrate 100 may cause variations in the timing of freezing for each substrate 100.

[0107] According to this embodiment, the control unit 9 can control at least one of the flow rates of gas 10d and cooling gas 3a1, or the mixing ratio of gas 10d and cooling gas 3a1, based on the temperature measured by the temperature measuring unit 8a.

[0108] Therefore, the control unit 9 performs such control in the preliminary process and switches from the preliminary process to the supercooling process (stopping the supply of liquid 101) after the difference between the temperature detected by the measurement unit 8 and the temperature detected by the temperature measurement unit 8a falls within a predetermined range. In this way, freezing can be started when the temperature gradient in the thickness direction of the substrate 100 has become small, thereby suppressing variations in the timing of freezing.

[0109] Furthermore, it is also possible to control the supercooling state of the liquid 101 by controlling the flow rate of the gas 10d supplied from the gas supply unit 10, without controlling the flow rate of the cooling gas 3a1 with the flow rate control unit 3c (by keeping the flow rate of the cooling gas 3a1 constant). In such cases, the flow rate control unit 3c can be omitted. However, if the flow rate control unit 3c and the gas supply unit 10 are provided, it becomes easier to control the supercooling state of the liquid 101. Furthermore, the supercooling state of the liquid 101 can be controlled by controlling the amount of air 7a supplied by the blower unit 7.

[0110] Furthermore, the plate 2d improves the cooling efficiency of the outer periphery of the substrate, allowing the temperature of the cooling gas 3a1 to be set higher than before. Therefore, in the method of generating the cooling gas 3a1 in the coolant section 3a, it becomes possible to mix in a less expensive room-temperature gas compared to the cooling gas 3a1, thereby reducing costs. In addition, in methods of cooling the gas using a chiller or the like, the set temperature of the cooling gas 3a1 can be set higher than before, reducing the load on the chiller and resulting in energy savings.

[0111] The embodiments described above are illustrative examples. However, the present invention is not limited to these descriptions. With respect to the embodiments described above, those who are skilled in the art may add, delete, or modify components, or add, omit, or change processes as appropriate, and these are also included within the scope of the present invention as long as they retain the features of the present invention.

[0112] For example, the shape, dimensions, number, and arrangement of each element of the substrate processing apparatus 1 are not limited to those exemplified and can be changed as appropriate.

[0113] Furthermore, although the above example illustrates the case where the planar shape of the substrate 100 is rectangular, the same method can be used when the planar shape of the substrate 100 is circular or other shapes. For example, a hole corresponding to the planar shape of the substrate 100 can be provided in the central part of a single plate-like body. A substrate 100 with a circular planar shape can be, for example, a semiconductor wafer.

[0114] Alternatively, the plate 2d may be attached to the circuit board 100 outside the housing 6. The circuit board 100 is transported into the housing 6 together with the attached plate 2d. [Explanation of Symbols]

[0115] 1 Substrate processing apparatus, 1a Substrate processing apparatus, 2 Mounting section, 2a Mounting table, 2a1 Support section, 2aa Hole, 2b Rotating shaft, 2c Drive section, 2d Plate, 3 Cooling section, 3a Cooling liquid section, 3a1 Cooling gas, 4 First liquid supply section, 5 Second liquid supply section, 6 Housing, 9 Control section, 10 Gas supply section, 10d Gas, 100 Substrate, 100a Back side, 100b Front side, 101 Liquid, 102 Liquid

Claims

1. A rotatable mounting base is provided with multiple support parts capable of supporting a rectangular substrate so as to form a space between the substrate and the support part, A cooling unit capable of supplying cooling gas to the space between the mounting base and the substrate, The substrate has a liquid supply unit capable of supplying liquid to the side opposite to the side facing the base described above, It comprises a plate that is plate-shaped and surrounds the periphery of the substrate, extending to extend the periphery of the substrate, so as to form a space between it and the aforementioned stand through which the cooling gas flows, A substrate processing apparatus wherein the plurality of support portions are provided below the plate and in a position that can contact the edge of the back surface of the substrate.

2. The substrate processing apparatus according to claim 1, wherein the plurality of support parts are provided in pairs at positions that sandwich each of the four corners of the substrate.

3. The substrate processing apparatus according to claim 1 or 2, wherein the plate is provided with a groove at a position corresponding to the support portion.

4. The substrate processing apparatus according to any one of claims 1 to 3, wherein the outer shape of the plate is larger than the circumscribed circle of the substrate.

5. The aforementioned plate is made up of multiple small pieces of the same shape, The substrate processing apparatus according to any one of claims 1 to 4, wherein the mounting section comprises a drive unit for moving the plurality of small pieces.

6. The substrate processing apparatus according to any one of claims 1 to 5, wherein the plate comprises an elastic body coated with a liquid-repellent material on the side surface facing the substrate, in contact with the side surface of the substrate.

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