Wafer drying apparatus and wafer drying method

Abstract

To provide a wafer drying device and a wafer drying method, capable of reducing an exhaust time of a supercritical fluid.SOLUTION: A wafer drying device 100 contains: a supercritical fluid supply module 120 that is connected to a drying chamber 140; a main exhaust line 150 in which a main valve 151 is installed; and an assistance exhaust unit 160 which is connected to the main exhaust line 150. The assistance exhaust unit contains: an assistance exhaust line 161 that performs an exhaust from the drying chamber 140 at the time of a closing of the main valve; a negative pressure tank 162 that is installed to the assistance exhaust line; a first valve 163a that is arranged on a front step of the negative pressure tank and is opened at the time of the closing of the main valve; and a second valve 163b that is arranged at a rear step of the negative pressure tank and is opened in communicated with the first valve. An inner pressure of the drying chamber is a first pressure or less, and a ratio of a pressure reduction amount in the drying chamber against an exhaust time of the supercritical fluid through the assistance exhaust unit is 0.75 to 9.0 (bar / sec).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wafer drying apparatus and a wafer drying method. Background Art

[0002] To realize finer patterns, the introduction of EUV lithography processes has been gradually increasing. As the critical dimension (CD) of the exposed photoresist (PR, Photo-Resist) gradually decreases, the conventional method of processing a developing solution on a substrate, rotating it at high speed and drying during the PR development process has a problem that it is difficult to prevent pattern collapse.

[0003] This is because a tensile force acts between patterns during drying due to the influence of the surface tension of the developing solution. Such a problem can be solved when drying is performed after replacing the developing solution using a supercritical fluid that has almost no surface tension. Summary of the Invention Problems to be Solved by the Invention

[0004] One of the technical problems to be achieved by the technical idea of the present invention is to provide a wafer drying apparatus and a wafer drying method capable of shortening the exhaust time of a supercritical fluid.

[0005] Another one of the technical problems to be achieved by the technical idea of the present invention is to provide a wafer drying apparatus and a wafer drying method capable of preventing contamination of wafers and drying chambers by impurities. Means for Solving the Problems

[0006] An exemplary wafer drying apparatus includes a drying chamber having an internal space, a supercritical fluid supply module connected to the drying chamber and supplying supercritical fluid, a main exhaust line connected to the drying chamber and having a main valve installed, and an auxiliary exhaust unit connected to the main exhaust line. The supercritical fluid supply module includes a fluid storage tank, a condenser connected to the fluid storage tank for pressurizing the fluid, a module pump located downstream of the condenser, a reservoir tank located downstream of the module pump for storing the pressurized fluid, and a heater located downstream of the reservoir tank for heating the fluid. The auxiliary exhaust unit includes an auxiliary exhaust line connected to the main exhaust line for exhausting from the drying chamber when the main valve is closed, a negative pressure tank installed in the auxiliary exhaust line, a first valve installed in the auxiliary exhaust line so as to be located upstream of the negative pressure tank and which opens when the main valve is closed, and a second valve installed in the auxiliary exhaust line so as to be located downstream of the negative pressure tank and which opens in conjunction with the first valve. When the internal pressure of the drying chamber is less than or equal to the first pressure, the ratio of the pressure decrease in the drying chamber to the exhaust time of the supercritical fluid exhausted through the auxiliary exhaust unit can be in the range of 0.75 to 9.0 (bar / sec). [Effects of the Invention]

[0007] This invention provides a wafer drying apparatus and wafer drying method that can shorten the exhaust time of the supercritical fluid.

[0008] Furthermore, a wafer drying apparatus and wafer drying method can be provided that can prevent contamination of wafers and drying chambers by impurities.

[0009] The diverse and beneficial advantages and effects of the present invention are not limited to those described above and can be more easily understood in the process of describing specific embodiments of the present invention. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment. [Figure 2] This graph illustrates the exhaust time of a wafer drying apparatus according to an exemplary embodiment. [Figure 3] This graph illustrates the effects of a wafer drying apparatus according to an exemplary embodiment. [Figure 4] This is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment. [Figure 5] This is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment. [Figure 6] This is a perspective view showing the impeller of an auxiliary exhaust pump according to an exemplary embodiment. [Figure 7] This is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment. [Figure 8] This is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment. [Figure 9] This is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment. [Figure 10] This is a flowchart illustrating a wafer drying method according to an exemplary embodiment. [Figure 11] This is a flowchart illustrating the exhaust step of a wafer drying method according to an exemplary embodiment. [Figure 12] This is a flowchart illustrating the first exhaust step of a wafer drying method according to an exemplary embodiment. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described below with reference to the attached drawings.

[0012] Figure 1 is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment.

[0013] Referring to FIG. 1, the wafer drying apparatus 100 is an example, and includes a supercritical fluid supply module 120, a drying chamber 140, a main exhaust line 150, and an auxiliary exhaust unit 160.

[0014] The supercritical fluid supply module 120 is connected to the drying chamber 140 and supplies supercritical fluid to the drying chamber 140. The supercritical fluid supply module 120 is an example, and may include a fluid storage tank 121, a condensor 122, a pump 123, a reservoir tank 124, a heater 125, a filter 126, a valve 127, and a supply line 128.

[0015] The fluid storage tank 121 has an internal space and stores low-temperature fluid therein. For example, the fluid stored in the fluid storage tank 121 may be low-temperature CO₂. The low-temperature CO₂ may be CO₂ at a temperature of about 35°C to 70°C.

[0016] The condensor 122 is connected to the fluid storage tank 121 and pressurizes the supplied low-temperature CO₂, which is the fluid. That is, the condensor 122 is connected to the fluid storage tank 121 via the supply line 128, and pressurizes the low-temperature CO₂ supplied from the fluid storage tank 121.

[0017] The pump 123 is disposed at a downstream stage of the condensor 122, and is connected to the condensor 122 via the supply line 128. The pump 123 serves to provide a driving force for supplying fluid to the drying chamber 140. In addition, the pump 123 may also serve to pressurize the fluid supplied into the drying chamber 140 so that the fluid is converted into a supercritical fluid.

[0018] The reservoir tank 124 is arranged downstream of the pump 123 and connected to the pump 123 via a supply line 128. The reservoir tank 124 serves to allow the fluid that has passed through the condenser 122 to be supplied to the drying chamber 140 after being mixed. For this reason, the reservoir tank 124 can have an internal space that allows sufficient mixing of the fluid that has passed through the condenser 122.

[0019] The heater 125 is connected to the reservoir tank 124 via the supply line 128, and serves to heat the fluid supplied from the reservoir tank 124. Thereby, the fluid heated by the heater 125 can be supplied to the drying chamber 140 via the supply line 128. As an example, the fluid heated by the heater 125 can be high-temperature CO₂. Here, the high-temperature CO₂ can be CO₂ at 70°C to 1200°C.

[0020] A plurality of filters 126 can be installed in the supply line 128. The filter 126 serves to remove foreign matter from the fluid supplied to the drying chamber 140, so that pure fluid from which foreign matter has been removed is supplied to the drying chamber 140. As an example, the filter 126 can be installed on the supply line 128 so as to be arranged downstream of the fluid storage tank 121, the pump 123, and the heater 125.

[0021] The valve 127 is installed in the supply line 128, and a plurality of valves 127 can be provided. As an example, the valves 127 can be respectively arranged between the fluid storage tank 121 and the condenser 122, between the module pump 123 and the reservoir tank 124, between the reservoir tank 124 and the heater 125, and between the heater 125 and the drying chamber 140. However, the present invention is not limited thereto, and the valves 127 can be added or omitted as necessary.

[0022] In this way, the low-temperature CO2 supplied from the fluid storage tank 121 can be transformed into high-temperature, high-pressure CO2 as it passes through the condenser 122, reservoir tank 124, and heater 125, and then supplied to the drying chamber 140.

[0023] The drying chamber 140 has an internal space and dries wafers with residual developer using a supercritical fluid. The drying chamber 140 may be equipped with a fixed mounting stand (not shown) on which developed wafers are placed. The drying chamber 140 is sealed from the outside during wafer drying. Meanwhile, the supercritical fluid, after being thoroughly mixed with the developer, is discharged from the drying chamber 140 through the main exhaust line 150.

[0024] On the other hand, a supercritical fluid is a state of matter that exists at a temperature and pressure above the critical point where liquid and gas are separated. For example, a supercritical fluid can be supercritical CO2. The pressure of supercritical CO2 is 73 bar or higher, and the temperature of the supercritical CO2 can be 33.1°C or higher.

[0025] The main exhaust line 150 is connected to the drying chamber 140 and is used to exhaust the supercritical fluid mixed with the developer (hereinafter, the supercritical fluid mixed with the developer is referred to as the supercritical fluid) to the outside. For example, a main valve 151 is installed in the main exhaust line 150, and exhaust can be performed through the main exhaust line 150 or the auxiliary exhaust line 161 described later by opening and closing the main valve 151. On the other hand, the supercritical fluid exhausted from the drying chamber 140 is exhausted through the main exhaust line 150 to a first pressure, and the pressure in the drying chamber 140 at this time can be a high pressure of 80 bar or more. On the other hand, the first pressure is just an example and can be a value in the range of 20 bar to 80 bar.

[0026] The auxiliary exhaust unit 160 increases the exhaust velocity of the supercritical fluid being exhausted from the drying chamber 140. For example, the auxiliary exhaust unit 160 includes an auxiliary exhaust line 161, a negative pressure tank 162, a first valve 163a, a second valve 163b, negative pressure forming piping 164, and a negative pressure forming pump 165.

[0027] The auxiliary exhaust line 161 is connected to the main exhaust line 150. The auxiliary exhaust line 161 provides a passage for exhausting the supercritical fluid at a pressure below the first pressure when the pressure in the drying chamber 140 reaches the first pressure.

[0028] The negative pressure tank 162 is installed on the auxiliary exhaust line 161 and is connected to the drying chamber 140 when the pressure in the drying chamber 140 reaches the first pressure. As a result, the pressure difference between the drying chamber 140 and the negative pressure tank 162 becomes greater than the pressure difference between the drying chamber 140 and atmospheric pressure. Therefore, even when the pressure in the drying chamber 140 falls below the first pressure, the exhaust velocity of the supercritical fluid from the drying chamber 140 can proceed more rapidly. On the other hand, the negative pressure tank 162 is kept closed with the main valve 151 open and the first and second valves 163a and 163b closed until the pressure in the drying chamber 140 reaches the first pressure. Thereafter, when the pressure in the drying chamber 140 reaches the first pressure, the main valve 151 is closed and the first and second valves 163a and 163b are opened, connecting the negative pressure tank 162 and the drying chamber 140. As a result, the supercritical fluid is exhausted through the auxiliary exhaust line 161.

[0029] The first valve 163a is installed in the auxiliary exhaust line 161 so as to be positioned in front of the negative pressure tank 162, and the second valve 163b is installed in the auxiliary exhaust line 161 so as to be positioned behind the negative pressure tank 162.

[0030] For example, until the pressure in the drying chamber 140 reaches a first pressure, the main valve 151 installed in the main exhaust line 150 is kept open so that the supercritical fluid is exhausted only through the main exhaust line 150. Thereafter, once the pressure in the drying chamber 140 reaches the first pressure, the main valve 151 installed in the main exhaust line 150 is closed, and the two first and second valves 163a and 163b installed in the auxiliary exhaust line 161 are opened so that the supercritical fluid is exhausted only through the auxiliary exhaust line 161.

[0031] On the other hand, when the pressure in the drying chamber 140 reaches the second pressure, the main valve 151 installed in the main exhaust line 150 is opened and the first and second valves 163a and 163b installed in the auxiliary exhaust line 161 are closed in order to prevent the pressure in the drying chamber 140 from becoming negative. As a result, exhaust from the drying chamber 140 is carried out only through the main exhaust line 150. At this time, exhaust from the drying chamber 140 is carried out by the pressure difference between the pressure in the drying chamber 140 and atmospheric pressure. Meanwhile, the second pressure can be approximately higher than atmospheric pressure and have a value of 2 bar or less. Hereafter, exhaust carried out by the pressure difference between the pressure in the drying chamber 140 and atmospheric pressure will be referred to as natural exhaust. Meanwhile, negative pressure means a pressure lower than atmospheric pressure.

[0032] The negative pressure forming pipe 164 is connected to the negative pressure tank 162. For example, once the exhaust of the supercritical fluid through the negative pressure tank 162 is complete, the negative pressure forming pipe 164 serves as a pipe connected to the negative pressure tank 162 to form a negative pressure in the negative pressure tank 162. On the other hand, an on / off valve 164a for opening and closing the negative pressure forming pipe 164 can be installed in the negative pressure forming pipe 164.

[0033] The negative pressure forming pump 165 is responsible for exhausting the fluid stored in the negative pressure tank 162 in order to create a negative pressure in the negative pressure tank 162. On the other hand, when the negative pressure forming pump 165 is driven, the on / off valve 164a is opened, and all of the above-mentioned valves 163 are closed.

[0034] As described above, when the pressure in the drying chamber 140 is below the first pressure through the auxiliary exhaust unit 160, the exhaust time of the supercritical fluid exhausted from the drying chamber 140 can be reduced. This reduces contamination by foreign matter.

[0035] To explain this in more detail, as shown in Figure 2, when the pressure in the drying chamber 140 is below the first pressure P1 and the supercritical fluid is continuously exhausted through the main exhaust line 150, the exhaust time required is approximately 60 seconds. However, when the supercritical fluid is exhausted through the auxiliary exhaust line 161 of the auxiliary exhaust unit 160, the exhaust time required is approximately 15 seconds. In other words, it can be seen that the exhaust time is reduced by utilizing the pressure difference between the negative pressure tank 162 of the auxiliary exhaust unit 160 and the drying chamber 140 to exhaust the supercritical fluid from the drying chamber 140.

[0036] In other words, as shown in Figure 2, when the pressure in the drying chamber 140 is below the first pressure P1 and the supercritical fluid is continuously exhausted through the main exhaust line 150, the ratio (slope) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid is in absolute value smaller than the ratio (slope) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid when the supercritical fluid is exhausted through the auxiliary exhaust line 161 of the auxiliary exhaust unit 160 when the pressure in the drying chamber 140 is below the first pressure P1.

[0037] However, when the pressure in the drying chamber 140 is less than or equal to the first pressure P1, the ratio (gradient) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid is not limited to the embodiment shown in Figure 2.

[0038] For example, if the first pressure P1 is 80 bar, and the section of the drying chamber 140 pressure from 80 bar to 20 bar is called the first section, and the section of the drying chamber 140 pressure below 20 bar is called the second section, then the ratio (gradient) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid in the first section can be in the range of 0.75 to 9.0 (bar / sec), and the ratio (gradient) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid in the second section can be in the range of 0.95 to 2 (bar / sec). Therefore, when the pressure is below the first pressure P1, the ratio (gradient) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid can be in the range of 0.75 to 9.0 (bar / sec).

[0039] Furthermore, when the pressure in the drying chamber 140 is less than or equal to the first pressure P1, the exhaust time of the supercritical fluid can be in the range of 10s to 50s.

[0040] As shown in Figure 3, when the exhaust time is 15 seconds, the occurrence of defects due to re-adsorption of foreign matter is reduced by approximately 84% compared to when the exhaust time is 60 seconds.

[0041] Thus, when the pressure in the drying chamber 140 is below the first pressure via the auxiliary exhaust unit 160, the exhaust time of the supercritical fluid exhausted from the drying chamber 140 can be reduced. This can reduce contamination by foreign matter.

[0042] Furthermore, if the pressure in the drying chamber 140 is below the second pressure, exhaust can be performed through natural ventilation to prevent negative pressure from being generated in the drying chamber 140. This prevents the supercritical fluid mixed with the exhausted developer from flowing back into the drying chamber 140 and contaminating the drying chamber 140 or the wafer.

[0043] Figure 4 is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment.

[0044] Referring to Figure 4, the wafer drying apparatus 200 is an example and includes a supercritical fluid supply module 120, a drying chamber 140, a main exhaust line 150, and an auxiliary exhaust unit 260.

[0045] On the other hand, the supercritical fluid supply module 120, the drying chamber 140, and the main exhaust line 150 are substantially the same as the components described in the above embodiment, so a detailed explanation is omitted here and replaced by the above explanation.

[0046] The auxiliary exhaust unit 260 is connected to the main exhaust line 150 and plays a role in increasing the exhaust velocity of the supercritical fluid exhausted from the drying chamber 140. For this reason, the auxiliary exhaust unit 260 may be equipped with an auxiliary exhaust line 261, an external air supply pipe 262, and a number of valves 263.

[0047] The auxiliary exhaust line 261 is connected to the main exhaust line 150. On the other hand, when the pressure in the drying chamber 140 reaches the first pressure, the auxiliary exhaust line 261 provides a passage for exhausting the supercritical fluid at a pressure below the first pressure. For example, the auxiliary exhaust line 261 has an orifice section 261a. The orifice section 261a is configured to generate negative pressure, so that external air supplied through the external air supply pipe 262 passes through the orifice section 261a, creating negative pressure in the orifice section 261a. This can increase the exhaust velocity of the supercritical fluid flowing along the auxiliary exhaust line 161.

[0048] The external air supply line 262 is connected to the orifice section 261a of the auxiliary exhaust line 261, and supplies external air so that it passes through the orifice section 261a. For this reason, a supply pump 262a can be installed in the external air supply line 262. In this way, external air is supplied through the external air supply line 262 so that it passes through the orifice section 261a of the auxiliary exhaust line 261, creating a negative pressure in the orifice section 261a. As a result, when the pressure in the drying chamber 140 is below the first pressure, the pressure difference between the pressure in the drying chamber 140 and the orifice section 261a becomes greater than the pressure difference between the pressure in the drying chamber 140 and atmospheric pressure, so the exhaust velocity of the supercritical fluid from the drying chamber 140 can be increased.

[0049] On the other hand, an on / off valve 262b can be installed in the external air supply line 262, which is located downstream of the supply pump 262a. The on / off valve 262b can be opened only when external air is supplied to the orifice section 261a through the external air supply line 262.

[0050] The first and second valves 263a and 263b can be installed so as to be positioned before and after the orifice section 261a.

[0051] For example, until the pressure in the drying chamber 140 reaches a first pressure, the main valve 151 installed in the main exhaust line 150 is kept open so that the supercritical fluid is exhausted only through the main exhaust line 150. Thereafter, when the pressure in the drying chamber 140 reaches the first pressure, the main valve 151 installed in the main exhaust line 150 is closed, and the first and second valves 263a and 263b installed in the auxiliary exhaust line 261 are opened so that the supercritical fluid is exhausted through the auxiliary exhaust line 261.

[0052] On the other hand, when the pressure in the drying chamber 140 reaches the second pressure, the main valve 151 installed in the main exhaust line 150 is opened and the first and second valves 263a and 263b installed in the auxiliary exhaust line 261 are closed in order to prevent the pressure in the drying chamber 140 from becoming negative. As a result, exhaust from the drying chamber 140 is carried out only through the main exhaust line 150. At this time, exhaust from the drying chamber 140 is carried out by the pressure difference between the pressure in the drying chamber 140 and atmospheric pressure.

[0053] As described above, when the pressure in the drying chamber 140 is below the first pressure via the auxiliary exhaust unit 260, the exhaust time of the supercritical fluid exhausted from the drying chamber 140 can be reduced. This reduces contamination by foreign matter.

[0054] Furthermore, if the pressure in the drying chamber 140 is below the second pressure, negative pressure can be prevented from being generated in the drying chamber 140 by exhausting the fluid through natural ventilation. This prevents the supercritical fluid mixed with the exhausted developer from flowing back into the drying chamber 140 and contaminating the drying chamber 140 or the wafer.

[0055] Figure 5 is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment.

[0056] Referring to Figure 5, the wafer drying apparatus 300 is an example and includes a supercritical fluid supply module 120, a drying chamber 140, a main exhaust line 150, and an auxiliary exhaust unit 360.

[0057] On the other hand, the supercritical fluid supply module 120, the drying chamber 140, and the main exhaust line 150 are substantially the same as the components described in the above embodiment, so a detailed explanation is omitted here and replaced by the above explanation.

[0058] The auxiliary exhaust unit 360 is connected to the main exhaust line 150 and plays a role in increasing the exhaust velocity of the supercritical fluid exhausted from the drying chamber 140. For this reason, the auxiliary exhaust unit 360 may be equipped with an auxiliary exhaust line 361, an auxiliary exhaust pump 362, and a valve 363.

[0059] The auxiliary exhaust line 361 is connected to the main exhaust line 150. On the other hand, the auxiliary exhaust line 361 provides a passage for exhausting the supercritical fluid when the pressure in the drying chamber 140 is below the first pressure.

[0060] The auxiliary exhaust pump 362 is installed in the auxiliary exhaust line 361. The auxiliary exhaust pump 362 operates when the pressure in the drying chamber 140 is below the first pressure, and the valve 363 causes the supercritical fluid to flow into the auxiliary exhaust line 361. In this way, the auxiliary exhaust pump 362 exhausts the supercritical fluid from the drying chamber 140, thus reducing the exhaust time of the supercritical fluid compared to when the supercritical fluid is exhausted due to the pressure difference with atmospheric pressure, when the pressure in the drying chamber 140 is below the first pressure. On the other hand, as shown in Figure 6, the auxiliary exhaust pump 362 has a drive shaft 362a positioned in the center and an impeller 362c having a blade section 362b with a helical structure around the drive shaft 362a. The supercritical fluid flowing along the auxiliary exhaust line 361 flows into the center of the impeller 362c where the drive shaft 362a is located, then flows along the blade section 362b and flows to the outside of the impeller 362c. This reduces the risk of damage to the auxiliary exhaust pump 362 caused by the supercritical fluid, even when a high-density supercritical fluid flows into the auxiliary exhaust pump 362. In other words, because the incoming supercritical fluid collides with the drive shaft 362a, the relatively rigid drive shaft 362a is prevented from being damaged, thereby reducing the risk of damage to the auxiliary exhaust pump 362 caused by the supercritical fluid.

[0061] Valve 363 ensures that supercritical fluid flows into the auxiliary exhaust line 361. For this reason, the main valve 151 is installed in the main exhaust line 150, and valve 363 can be installed in the auxiliary exhaust line 361 so that it is positioned upstream of the auxiliary exhaust pump 362.

[0062] For example, until the pressure in the drying chamber 140 reaches a first pressure, the main valve 151 installed in the main exhaust line 150 is opened so that the supercritical fluid is exhausted only through the main exhaust line 150. Thereafter, when the pressure in the drying chamber 140 reaches the first pressure, the main valve 151 installed in the main exhaust line 150 is closed, and the valve 363 installed in the auxiliary exhaust line 361 is opened so that the supercritical fluid is exhausted only through the auxiliary exhaust line 161.

[0063] On the other hand, when the pressure in the drying chamber 140 reaches the second pressure, the main valve 151 installed in the main exhaust line 150 is opened and the valve 363 installed in the auxiliary exhaust line 361 is closed to prevent the pressure in the drying chamber 140 from becoming negative. As a result, exhaust from the drying chamber 140 is carried out only through the main exhaust line 150. At this time, exhaust from the drying chamber 140 is carried out by the pressure difference between the pressure in the drying chamber 140 and atmospheric pressure.

[0064] As described above, when the pressure in the drying chamber 140 is below the first pressure via the auxiliary exhaust unit 360, the exhaust time of the supercritical fluid exhausted from the drying chamber 140 can be reduced. This reduces contamination by foreign matter.

[0065] Furthermore, damage to the auxiliary exhaust pump 362 due to the flow of supercritical fluid can be reduced through the impeller 362c provided in the auxiliary exhaust pump 362.

[0066] Furthermore, if the pressure in the drying chamber 140 is below the second pressure, negative pressure can be prevented from being generated in the drying chamber 140 by exhausting the fluid through natural ventilation. This prevents the supercritical fluid mixed with the exhausted developer from flowing back into the drying chamber 140 and contaminating the drying chamber 140 or the wafer.

[0067] Figure 7 is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment.

[0068] Referring to Figure 7, the wafer drying apparatus 400 is an example and includes a supercritical fluid supply module 120, a drying chamber 140, a main exhaust line 150, a main negative pressure tank 460, and an auxiliary exhaust unit 160.

[0069] On the other hand, the supercritical fluid supply module 120, the drying chamber 140, and the main exhaust line 150 are substantially the same as the components described in the above embodiment, so a detailed explanation is omitted here and replaced by the above explanation. Also, the auxiliary exhaust unit 160 is substantially the same as the components described in the above embodiment, except for the main negative pressure tank 460, so a detailed explanation is omitted here.

[0070] The wafer drying apparatus 400 further includes a main negative pressure tank 460, which is installed in a bypass pipe 461 connected to the main exhaust line 150. The main negative pressure tank 460 may also have an internal volume larger than the internal volume of the drying chamber 140 for smooth exhaust of the supercritical fluid. For example, the main negative pressure tank 460 is connected to the main exhaust line 150 to shorten the exhaust time of the supercritical fluid when the pressure in the drying tank 140 is below the third pressure. As a result, until the pressure in the drying tank 140 reaches the first pressure from the third pressure, the supercritical fluid exhausted from the drying chamber 140 is exhausted to the outside via the main negative pressure tank 460. Thereafter, when the pressure in the drying tank 140 is below the first pressure, the supercritical fluid is exhausted by the auxiliary exhaust line 161.

[0071] On the other hand, the third pressure can have a value in the range of approximately 80 bar to 100 bar.

[0072] Furthermore, the bypass piping 461 can be equipped with multiple bypass valves 461a for regulating the flow of supercritical fluid through the bypass piping 461.

[0073] To briefly explain the exhaust method from the drying chamber 140, when exhaust begins from the drying chamber 140, the supercritical fluid is naturally exhausted through the main exhaust line 150. Subsequently, when the pressure in the drying chamber 140 reaches the third pressure, the supercritical fluid is exhausted through the main negative pressure tank 460. Subsequently, when the pressure in the drying chamber 140 reaches the first pressure, the supercritical fluid is exhausted through the auxiliary exhaust line 161.

[0074] In this way, since the main negative pressure tank 460 is installed in the main exhaust line 150, the exhaust time of the supercritical fluid until the pressure in the dry tank 140 goes from the third pressure to the first pressure can also be reduced. Therefore, the possibility of contamination due to re-adsorption of foreign matter can be further reduced.

[0075] On the other hand, the main negative pressure tank 460 may be equipped with a main negative pressure forming pipe 462 and a main negative pressure forming pump 464 installed in the negative pressure forming pipe 462. For example, when the pressure in the main negative pressure tank 460 is to become negative, the main negative pressure forming pump 464 is driven to discharge the fluid exhausted from the main negative pressure tank 460 to the outside air through the main negative pressure forming pipe 462. In addition, an on / off valve 466 may be installed in the main negative pressure forming pipe 462.

[0076] As described above, the supercritical fluid is exhausted through the main negative pressure tank 460 until the pressure in the drying chamber 140 reaches the first pressure, and if the pressure in the drying chamber 140 is below the first pressure, the supercritical fluid is exhausted through the negative pressure tank 162 of the auxiliary exhaust unit 160, thereby further reducing the exhaust time of the supercritical fluid. This further reduces contamination due to the re-adsorption of foreign matter.

[0077] Figure 8 is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment.

[0078] Referring to Figure 8, the wafer drying apparatus 500 is an example and includes a supercritical fluid supply module 120, a drying chamber 140, a main exhaust line 150, a main negative pressure tank 560, and an auxiliary exhaust unit 260.

[0079] On the other hand, the supercritical fluid supply module 120, the drying chamber 140, and the main exhaust line 150 are substantially the same as the components described in the above embodiment, so a detailed explanation is omitted here and replaced by the above explanation. Also, the auxiliary exhaust unit 260 is substantially the same as the components described in the above embodiment, except for the main negative pressure tank 560, so a detailed explanation is omitted here.

[0080] The auxiliary exhaust unit 260 further includes a main negative pressure tank 560, which is installed in a bypass pipe 561 connected to the main exhaust line 150. The bypass pipe 561 may also be equipped with several bypass valves 561a for regulating the flow of the supercritical fluid through it. Furthermore, the main negative pressure tank 560 may have an internal volume larger than the internal volume of the drying chamber 140 to ensure smooth exhaust of the supercritical fluid. For example, the main negative pressure tank 560 is connected to the main exhaust line 150 to shorten the exhaust time of the supercritical fluid when the pressure in the drying tank 140 is below the third pressure. This ensures that the supercritical fluid exhausted from the drying chamber 140 is exhausted to the outside via the main negative pressure tank 560 until the pressure in the drying tank 140 drops from the third pressure to the first pressure. Thereafter, if the pressure in the drying tank 140 is below the first pressure, the supercritical fluid is exhausted through the auxiliary exhaust line 261.

[0081] In this way, since the main negative pressure tank 560 is installed in the main exhaust line 150, the exhaust time of the supercritical fluid until the pressure in the dry tank 140 reaches the first pressure can also be reduced. Therefore, the possibility of contamination due to re-adsorption of foreign matter can be further reduced.

[0082] On the other hand, the main negative pressure tank 560 may be equipped with a main negative pressure forming pipe 562 and a main negative pressure forming pump 564 installed in the negative pressure forming pipe 562. For example, when the pressure in the main negative pressure tank 560 is to become negative, the main negative pressure forming pump 564 is driven to discharge the fluid exhausted from the main negative pressure tank 560 to the outside air through the main negative pressure forming pipe 562. In addition, an on / off valve 566 may be installed in the main negative pressure forming pipe 562.

[0083] As described above, the supercritical fluid can be exhausted through the main negative pressure tank 560 until the pressure in the drying chamber 140 reaches the first pressure, and if the pressure in the drying chamber 140 is below the first pressure, the supercritical fluid can be exhausted through the auxiliary exhaust line 261, thereby further reducing the exhaust time of the supercritical fluid. This further reduces contamination due to the re-adsorption of foreign matter.

[0084] Figure 9 is a schematic diagram showing a wafer drying apparatus according to an exemplary embodiment.

[0085] Referring to Figure 9, the wafer drying apparatus 600 is an example and includes a supercritical fluid supply module 120, a drying chamber 140, a main exhaust line 150, a main negative pressure tank 660, and an auxiliary exhaust unit 360.

[0086] On the other hand, the supercritical fluid supply module 120, the drying chamber 140, and the main exhaust line 150 are substantially the same as the components described in the above embodiment, so a detailed explanation is omitted here and replaced by the above explanation. Also, the auxiliary exhaust unit 360 is substantially the same as the components described in the above embodiment, except for the main negative pressure tank 660, so a detailed explanation is omitted here.

[0087] The wafer drying apparatus 600 further includes a main negative pressure tank 660, which is installed in a bypass pipe 661 connected to the main exhaust line 150. Furthermore, the bypass pipe 661 may be equipped with multiple bypass valves 661a for controlling the flow of supercritical fluid through the bypass pipe 661. The main negative pressure tank 660 may also have an internal volume larger than the internal volume of the drying chamber 140 for smooth exhaust of the supercritical fluid. As an example, the main negative pressure tank 660 is connected to the main exhaust line 150 to shorten the exhaust time of the supercritical fluid when the pressure in the drying tank 140 is below the third pressure. As a result, until the pressure in the drying tank 140 reaches the first pressure from the third pressure, the supercritical fluid exhausted from the drying chamber 140 is exhausted to the outside via the main negative pressure tank 660. Thereafter, when the pressure in the drying tank 140 is below the first pressure, the supercritical fluid is exhausted by the auxiliary exhaust line 361.

[0088] In this way, since the main negative pressure tank 660 is installed in the main exhaust line 150, the exhaust time of the supercritical fluid until the pressure in the dry tank 140 reaches the first pressure can also be reduced. Therefore, the possibility of contamination due to re-adsorption of foreign matter can be further reduced.

[0089] On the other hand, the main negative pressure tank 660 may be equipped with a main negative pressure forming pipe 662 and a main negative pressure forming pump 664 installed in the negative pressure forming pipe 662. For example, when the pressure in the main negative pressure tank 660 is to become negative, the main negative pressure forming pump 664 is driven to discharge the fluid exhausted from the main negative pressure tank 660 to the outside air through the main negative pressure forming pipe 662. In addition, an on / off valve 666 may be installed in the main negative pressure forming pipe 662.

[0090] As described above, the supercritical fluid is exhausted through the main negative pressure tank 660 until the pressure in the drying chamber 140 reaches the first pressure, and if the pressure in the drying chamber 140 is below the first pressure, the supercritical fluid is exhausted through the auxiliary exhaust pump 362 of the auxiliary exhaust unit 360, thereby further reducing the exhaust time of the supercritical fluid. This further reduces contamination due to the re-adsorption of foreign matter.

[0091] Figure 10 is a flowchart showing a wafer drying method according to an exemplary embodiment, Figure 11 is a flowchart showing the exhaust step included in the wafer drying method according to an exemplary embodiment, and Figure 12 is a flowchart for explaining the first exhaust step of the wafer drying method according to an exemplary embodiment.

[0092] Referring to Figure 10, the supercritical fluid is supplied to the drying chamber (S110). Thereafter, with the drying chamber closed, the developer remaining on the wafer is dried by the supercritical fluid (S120). After the drying of the developer is complete, the supercritical fluid is evacuated from the drying chamber (S130).

[0093] On the other hand, referring to Figure 11, the supercritical fluid is evacuated from the drying chamber until the internal pressure of the drying chamber reaches a first pressure (S132). In other words, the wafer drying method includes a first evacuation step in which the supercritical fluid is evacuated from the drying chamber until the internal pressure of the drying chamber reaches a first pressure.

[0094] As an example, the first exhaust stage, as shown in Figure 12, may comprise a first-first exhaust stage (S132-1) in which the supercritical fluid is exhausted from the drying chamber by natural exhaust until the internal pressure of the drying chamber reaches a third pressure, and a first-second exhaust stage (S132-2) in which the supercritical fluid is exhausted by the pressure difference between the main negative pressure tank and the drying chamber until the internal pressure of the drying chamber goes from the third pressure to the first pressure.

[0095] However, it is not limited to this, and the first exhaust stage does not comprise the 1-1 exhaust stage and the 1-2 exhaust stage, and the supercritical fluid can be exhausted by natural exhaust alone until the internal pressure of the drying chamber reaches the first pressure.

[0096] On the other hand, the third pressure can have a value within approximately 80 bar to 100 bar.

[0097] Thereafter, when the internal pressure of the drying chamber is below the first pressure, a second exhaust stage can be performed in which the supercritical fluid is exhausted from the drying chamber through the auxiliary exhaust unit (S134). To explain this in more detail, when the pressure in the drying chamber reaches the first pressure, the main valve installed in the main exhaust line is closed, and the first and second valves installed in the auxiliary exhaust line are opened to exhaust the supercritical fluid through the negative pressure tank or orifice installed in the auxiliary exhaust line. Alternatively, when the pressure in the drying chamber reaches the first pressure, the main valve installed in the main exhaust line is closed, and the first and second valves installed in the auxiliary exhaust line are opened to exhaust the drying chamber by the auxiliary exhaust pump of the auxiliary exhaust unit.

[0098] In this case, the exhaust of the supercritical fluid from the drying chamber can be performed by the pressure difference between the internal pressure of the drying chamber and the negative pressure formed by the negative pressure tank or orifice of the auxiliary exhaust unit. Alternatively, the exhaust of the supercritical fluid from the drying chamber can be performed by the auxiliary exhaust pump of the auxiliary exhaust unit. Compared to exhausting the supercritical fluid by natural exhaust through the pressure difference between atmospheric pressure and the drying chamber, exhausting the supercritical fluid from the drying chamber through the auxiliary exhaust unit can shorten the exhaust time of the supercritical fluid.

[0099] On the other hand, to explain this in more detail, as shown in Figure 2, when the pressure in the drying chamber is below the first pressure P1, it can be seen that continuously exhausting the supercritical fluid through the main exhaust line takes approximately 60 seconds. However, when the supercritical fluid is exhausted through the auxiliary exhaust line of the auxiliary exhaust unit, it takes approximately 15 seconds. In other words, it can be seen that the exhaust time is reduced when the supercritical fluid is exhausted from the drying chamber by utilizing the pressure difference between the negative pressure tank of the auxiliary exhaust unit and the drying chamber.

[0100] In other words, as shown in Figure 2, when the pressure in the drying chamber is below the first pressure and the supercritical fluid is continuously exhausted through the main exhaust line, the ratio (slope) of the pressure decrease in the drying chamber to the exhaust time of the supercritical fluid is in absolute value smaller than the ratio (slope) of the pressure decrease in the drying chamber 140 to the exhaust time of the supercritical fluid when the pressure in the drying chamber is below the first pressure P1 and the supercritical fluid is exhausted through the auxiliary exhaust line of the auxiliary exhaust unit.

[0101] However, when the pressure in the drying chamber is below the first pressure, the ratio (gradient) of the pressure decrease in the drying chamber to the exhaust time of the supercritical fluid is not limited to the embodiment shown in Figure 2.

[0102] For example, if the first pressure P1 is 80 bar, and the section of the drying chamber pressure from 80 bar to 20 bar is called the first section, and the section of the drying chamber pressure below 20 bar is called the second section, then the ratio (slope) of the decrease in the drying chamber pressure to the exhaust time of the supercritical fluid in the first section can be in the range of 0.75 to 9.0 (bar / sec), and the ratio (slope) of the decrease in the drying chamber pressure to the exhaust time of the supercritical fluid in the second section can be in the range of 0.95 to 2 (bar / sec). Therefore, when the pressure is below the first pressure P1, the ratio (slope) of the decrease in the drying chamber pressure to the exhaust time of the supercritical fluid can be in the range of 0.75 to 9.0 (bar / sec).

[0103] Furthermore, when the pressure in the drying chamber 140 is less than or equal to the first pressure P1, the exhaust time of the supercritical fluid can be in the range of 10s to 50s.

[0104] Thereafter, if the internal pressure of the drying chamber is below the second pressure, a third exhaust stage can be performed to exhaust the supercritical fluid from the drying chamber by natural exhaust (S136). This prevents the formation of negative pressure in the drying chamber. Thus, it is possible to prevent foreign matter from re-inflowing into the drying chamber and re-adhering to the drying chamber or wafer. According to embodiments, the apparatus of the present invention may further include a control unit configured to control any number of other components of the present invention (e.g., valves, condensers, pumps, heaters, and / or the drying chamber) to perform their respective functions. For example, the control unit may be configured to control other components of the apparatus of the present invention to perform the method described with respect to Figures 10 to 12 or / or other methods of the present invention. According to embodiments, the apparatus of the present invention may further include a sensor (e.g., a pressure sensor) for sensing the pressure inside the apparatus, and the control unit may be configured to control the apparatus according to the method of the present invention by obtaining a pressure value from the sensor and determining other components (e.g., valves) based on the obtained pressure value in relation to the first, second, and / or third pressures.

[0105] According to the embodiment, the control unit may include at least one processor and memory for storing computer instruction words. When the computer instruction is executed by at least one processor, the controller may perform its function.

[0106] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to those with ordinary skill in the art that various modifications and variations are possible without departing from the technical idea of ​​the present invention as described in the claims. [Explanation of Symbols]

[0107] 100, 200, 300, 400, 500, 600: Wafer drying equipment 120: Supercritical fluid supply module 140: Drying Chamber 150: Main exhaust line 160, 260, 360: Auxiliary exhaust unit 460, 560, 660: Main vacuum tank

Claims

1. A drying chamber having an internal space, A supercritical fluid supply module connected to the drying chamber and supplying supercritical fluid to the drying chamber, A main exhaust line connected to the drying chamber and equipped with a main valve, An auxiliary exhaust unit connected to the main exhaust line, Includes, The supercritical fluid supply module is Fluid storage tank and A condenser connected to the aforementioned fluid storage tank and configured to pressurize the fluid, A pump is placed downstream of the capacitor, A reservoir tank is located downstream of the pump and stores the fluid pressurized by the condenser, A heater is positioned downstream of the reservoir tank and configured to heat the fluid, Includes, The auxiliary exhaust unit is An auxiliary exhaust line is connected to the main exhaust line and configured to exhaust supercritical fluid from the drying chamber when the main valve is closed, A negative pressure tank installed in the auxiliary exhaust line, A first valve is installed in the auxiliary exhaust line so as to be positioned upstream of the negative pressure tank, and is configured to open when the main valve is closed. It includes a second valve, which is installed in the auxiliary exhaust line so as to be positioned downstream of the negative pressure tank and is configured to open in conjunction with the first valve, A wafer drying apparatus in which, when the internal pressure of the drying chamber is less than or equal to a first pressure, the ratio of the pressure decrease in the drying chamber to the exhaust time of the supercritical fluid exhausted through the auxiliary exhaust unit is in the range of 0.75 to 9.0 (bar / sec).

2. The auxiliary exhaust unit is A negative pressure forming pipe connected to the aforementioned negative pressure tank, A negative pressure forming pump is installed in the negative pressure forming piping and forms the negative pressure in the negative pressure tank, The wafer drying apparatus according to claim 1, further comprising:

3. The wafer drying apparatus according to claim 2, wherein the negative pressure forming pipe is equipped with an on / off valve for opening and closing the negative pressure forming pipe.

4. Further including a control unit, The control unit, when the pressure in the drying chamber is equal to or greater than the first pressure, opens the main valve, closes the first and second valves, and allows the supercritical fluid to be exhausted through the main exhaust line. The wafer drying apparatus according to any one of claims 1 to 3, wherein the control unit causes the main valve to close and the first and second valves to open when the pressure in the drying chamber is less than a first pressure, so that the supercritical fluid is exhausted through the auxiliary exhaust line.

5. The supercritical fluid is supercritical CO ２ The wafer drying apparatus according to any one of claims 1 to 4.

6. The system is configured such that when the supercritical fluid is exhausted from the drying chamber, the pressure of the supercritical fluid is 73 bar or higher. The wafer drying apparatus according to claim 5, wherein the apparatus is configured such that the temperature of the supercritical fluid is 33.1°C or higher when the supercritical fluid is discharged from the drying chamber.

7. The wafer drying apparatus according to claim 4, wherein the first pressure has a value in the range of 20 bar to 80 bar.

8. The wafer drying apparatus according to any one of claims 1 to 7, further comprising a main negative pressure tank installed in a bypass pipe connected to the main exhaust line.

9. The wafer drying apparatus according to claim 8, wherein the main negative pressure tank has an internal space with a volume greater than the internal space of the drying chamber.

10. The wafer drying apparatus according to any one of claims 1 to 9, wherein, when the internal pressure of the drying chamber is less than or equal to a first pressure, the exhaust time of the supercritical fluid exhausted through the auxiliary exhaust unit is within 10 s (sec) to 50 s.

11. The wafer drying apparatus according to any one of claims 1 to 10, wherein the supercritical fluid supply module further includes at least one filter located downstream of the fluid storage tank and at least one module valve located adjacent to the condenser, the reservoir tank and the heater.

12. The steps include supplying the supercritical fluid to the drying chamber, The steps include interrupting the supply of the supercritical fluid and drying the developer in the drying chamber, The steps include exhausting the supercritical fluid from the drying chamber, Includes, The step of exhausting the supercritical fluid is: Until the pressure in the drying chamber reaches a first pressure, only the main valve is opened to exhaust the supercritical fluid through the main exhaust line connected to the drying chamber. When the pressure in the drying chamber reaches the first pressure, the main valve is closed. The first valve and the second valve installed in the auxiliary exhaust line are opened to exhaust the supercritical fluid through the negative pressure tank installed in the auxiliary exhaust line. A wafer drying method wherein, when a supercritical fluid is exhausted through a negative pressure tank installed in the auxiliary exhaust line, the ratio of the pressure decrease in the drying chamber to the exhaust time of the supercritical fluid is in the range of 0.75 to 9.0 (bar / sec).

13. The wafer drying method according to claim 12, wherein when the supercritical fluid is exhausted through a negative pressure tank installed in the auxiliary exhaust line, the exhaust time of the supercritical fluid is within 10 s to 50 s.

14. The wafer drying method according to claim 13, wherein the first pressure has a value in the range of 20 bar to 80 bar.

15. A wafer drying method according to any one of claims 12 to 14, wherein when the pressure in the drying chamber reaches a second pressure, the first and second auxiliary valves are closed and the main valve is opened to exhaust the drying chamber through the main exhaust line.

16. The wafer drying method according to claim 15, wherein the second pressure has a value within the range of 2 bar at atmospheric pressure.

17. When the supercritical fluid is exhausted through the main exhaust line connected to the drying chamber until the pressure in the drying chamber reaches a first pressure, The supercritical fluid is exhausted through the main exhaust line only until the pressure in the drying chamber reaches a third pressure. A wafer drying method according to any one of claims 12 to 16, wherein when the pressure in the drying chamber reaches a third pressure, the main valve is closed and the first and second bypass valves installed in the bypass line connected to the main exhaust line are opened to exhaust the supercritical fluid through the main negative pressure tank installed in the bypass line.

18. The wafer drying method according to claim 17, wherein the third pressure has a value in the range of 80 bar to 100 bar.

19. A wafer drying method according to any one of claims 12 to 18, wherein, after exhausting the drying chamber is completed, the main valve and the first and second auxiliary valves are closed and a negative pressure forming valve installed in a negative pressure forming pipe connected to the negative pressure tank is opened, and a negative pressure is formed in the negative pressure tank through a negative pressure forming pump.

20. The supercritical fluid exhausted from the drying chamber is supercritical CO2. ２ The wafer drying method according to any one of claims 12 to 19.

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