Substrate drying apparatus and substrate drying method

Abstract

A substrate drying apparatus includes: a process chamber including a processing space for performing a drying process on a residual liquid remaining on a surface of a substrate; a first fluid supply device configured to supply a first fluid to the processing space, in which a solubility of the residual liquid in the first fluid is a first solubility; a second fluid supply device configured to supply a second fluid in a supercritical state to the processing space, in which a solubility of the residual liquid in the second fluid is a second solubility greater than the first solubility; and a discharge device configured to discharge the waste liquid in the processing space of the process chamber to the outside of the process chamber.

Description

Cross - reference to related applications

[0001] This application is based on and claims priority to Korean Patent Application No. 10 - 2024 - 0001063, filed with the Korean Intellectual Property Office on January 3, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical field

[0002] The technical idea of the present disclosure relates to a substrate drying apparatus and a substrate drying method, and more particularly, to a substrate drying apparatus and a substrate drying method for drying a substrate by using a supercritical fluid. Background art

[0003] As the requirements for miniaturization of semiconductor devices become increasingly high, an extreme ultraviolet (EUV) lithography method with an extremely short wavelength has been proposed. Using this EUV lithography technology, a photoresist pattern with a small critical dimension and a high aspect ratio can be used to form a fine pattern. In order to minimize the peeling or collapse of the fine pattern in the process of forming the fine pattern, a drying process using a supercritical fluid is adopted, but there is still room for improvement. Summary of the invention

[0004] The problem to be solved by the technical idea of the present disclosure is to provide a substrate drying apparatus and a substrate drying method for suppressing the phenomenon of fine pattern collapse during the drying process of a substrate.

[0005] In addition, the problems solved by the technical idea of the present disclosure are not limited to the above problems, and those skilled in the art can clearly understand other problems from the following description.

[0006] To solve the above problems, the technical idea of the present disclosure provides a substrate drying apparatus, including: a process chamber including a processing space for drying the residual liquid remaining on the surface of the substrate; a substrate support portion configured to support the substrate in the process chamber; a first fluid supply device configured to supply a first fluid to the processing space through a first supply pipe penetrating the process chamber, wherein the solubility of the residual liquid in the first fluid is a first solubility; a second fluid supply device configured to supply a second fluid in a supercritical state to the processing space through a second supply pipe penetrating the process chamber, wherein the solubility of the residual liquid in the second fluid is a second solubility greater than the first solubility; and a discharge device configured to discharge the waste liquid in the processing space of the process chamber to the outside of the process chamber through a discharge pipe penetrating the process chamber.

[0007] To solve the above problems, the technical idea of the present disclosure provides a substrate drying method, including: loading a substrate with residual liquid on its surface onto a substrate support portion in a process chamber; supplying a first fluid to a processing space in the process chamber and increasing the pressure in the processing space; supplying a second fluid in a supercritical state to the processing space in the process chamber to dissolve the residual liquid on the surface of the substrate; and discharging the waste liquid in the processing space to the outside of the process chamber. The solubility of the residual liquid in the first fluid is less than the solubility of the residual liquid in the second fluid.

[0008] To solve the above problems, the technical idea of the present disclosure provides a substrate drying method, including: loading a substrate with residual liquid on its surface onto a substrate support portion in a process chamber; supplying a first fluid in a supercritical state to a processing space in the process chamber by a first fluid supply device and increasing the pressure in the processing space; supplying a second fluid in a supercritical state to the processing space in the process chamber by a second fluid supply device and dissolving the residual liquid on the surface of the substrate in the second fluid; and discharging the waste liquid in the processing space to the outside of the process chamber. The substrate includes a plurality of fine patterns protruding upward from the upper surface of the substrate. In the operation of increasing the pressure in the processing space, the residual liquid covers the plurality of fine patterns of the substrate. When the pressure in the processing space reaches the process pressure, the second fluid is supplied to the processing space. The first fluid and the second fluid have different constituent materials. The solubility of the residual liquid in the first fluid is less than the solubility of the residual liquid in the second fluid. Description of the Drawings

[0009] Embodiments will be understood more clearly from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a diagram schematically showing a substrate processing apparatus according to an embodiment;

[0011] Figure 2 is a cross-sectional view schematically showing a substrate drying apparatus according to an embodiment;

[0012] Figure 3 shows Figure 2 the structure of the first fluid supply device and the second fluid supply device of the substrate drying apparatus;

[0013] Figure 4 is a cross-sectional view schematically showing a substrate drying apparatus according to an embodiment;

[0014] Figure 5 is a flowchart showing a substrate drying method according to an embodiment;

[0015] Figure 6 is a graph showing the pressure change in the processing space while a substrate drying process is being performed; and

[0016] Figures 7 to 10 is a cross-sectional view showing a substrate drying method in a process sequence according to an embodiment. Detailed Description

[0017] Since this embodiment can have various variations and various forms, some embodiments will be shown and described in detail in the drawings. However, this is not intended to limit this embodiment to a specific disclosed form.

[0018] Figure 1 is a diagram schematically showing a substrate processing apparatus 1 according to an embodiment.

[0019] Referring to Figure 1 , the substrate processing apparatus 1 may include an index module 10 and a processing module 20. According to an embodiment, the index module 10 and the processing module 20 may be arranged in one direction.

[0020] Hereinafter, the direction in which the index module 10 and the processing module 20 are arranged is defined as the first horizontal direction (X direction). When viewed from above, the direction perpendicular to the first horizontal direction (X direction) is defined as the second horizontal direction (Y direction), and the direction perpendicular to the plane including all of the first horizontal direction (X direction) and the second horizontal direction (Y direction) is defined as the vertical direction (Z direction).

[0021] The index module 10 may include a load port 120 and an index frame 140. The index module 10 may transfer the substrate W from the container F accommodating the substrate W to the processing module 20 that processes the substrate W. The index module 10 may accommodate the substrate W that has been completely processed by the processing module 20 in the container F.

[0022] The container F accommodating the substrate W may be placed on the load port 120. The load port 120 may be located on the opposite side of the processing module 20 based on the index frame 140.

[0023] In some embodiments, a plurality of load ports 120 may be provided. The plurality of load ports 120 may be arranged in a row along the second horizontal direction (Y direction). The number of load ports 120 may vary according to the process efficiency of the processing module 20, the floor area conditions, etc.

[0024] The container F may include a plurality of slots (not shown). The slots (not shown) may accommodate the substrate W arranged horizontally with respect to the ground. The container F may include an airtight container, such as a front-opening unified pod (FOUP). For example, the container F may be placed on the load port 120 by a transport device (not shown) (e.g., an overhead conveyor, an overhead transporter, or an automated guided vehicle) or by an operator.

[0025] The indexing frame 140 may include an indexing track 142 and an indexing robot 144. The indexing track 142 may extend in a second horizontal direction (Y direction). The indexing robot 144 may move along the indexing track 142 and transfer the substrate W to the processing module 20. The indexing robot 144 may transfer the substrate W between the indexing module 10 and the buffer unit 220.

[0026] The indexing robot 144 may include an indexing hand 146. The substrate W may be placed on the indexing hand 146. The indexing hand 146 may move along the indexing track 142 in the second horizontal direction (Y direction). For example, the indexing hand 146 may move forward and backward along the indexing track 142. In addition, the indexing hand 146 may be configured to be rotatable about a vertical direction (Z direction). In addition, the indexing hand 146 may be configured to be vertically movable along the vertical direction (Z direction).

[0027] In some embodiments, a plurality of indexing hands 146 may be provided. The plurality of indexing hands 146 may be arranged to be spaced apart in the up and down direction. The plurality of indexing hands 146 may move forward, backward, and rotationally independently of each other.

[0028] The processing module 20 may include a buffer unit 220, a transfer frame 240, a substrate liquid processing device 300, and a substrate drying device 400.

[0029] The buffer unit 220 may provide a space for temporarily placing the substrate W brought into the processing module 20 and the substrate W taken out of the processing module 20. The transfer frame 240 may provide a transfer space for transferring the substrate W between the buffer unit 220, the substrate liquid processing device 300, and the substrate drying device 400.

[0030] The buffer unit 220 may be disposed between the indexing frame 140 and the transfer frame 240. The buffer unit 220 may be located at one end of the transfer frame 240. The buffer unit 220 may include a plurality of slots (not shown) for arranging the substrate W. The plurality of slots may be arranged to be spaced apart from each other in the vertical direction (Z direction).

[0031] The front and back of the buffer unit 220 may be open. The front of the buffer unit 220 may include a face facing the indexing module 10, while the back of the buffer unit 220 may include a face facing the transfer frame 240. The indexing robot 144 may bring the substrate W into the buffer unit 220 through the front of the buffer unit 220, and the transfer robot 244 may take the substrate W out of the buffer unit 220 through the back of the buffer unit 220.

[0032] The transfer frame 240 may extend in a first horizontal direction (X direction). The substrate liquid processing apparatus 300 and the substrate drying apparatus 400 may be spaced apart from each other in a second horizontal direction (Y direction) and arranged on both sides of the transfer frame 240. For example, the transfer frame 240 and the substrate liquid processing apparatus 300 may be arranged in the second horizontal direction (Y direction). In addition, the transfer frame 240 and the substrate drying apparatus 400 may be arranged in the second horizontal direction (Y direction). In some embodiments, the substrate liquid processing apparatus 300 may be arranged closer to the buffer unit 220 than the substrate drying apparatus 400.

[0033] The transfer frame 240 may include a guide rail 242 and a transfer robot 244. The guide rail 242 may extend in a first horizontal direction (X direction). The transfer robot 244 may linearly move on the guide rail 242 in the first horizontal direction (X direction).

[0034] The transfer robot 244 may transfer the substrate W between the buffer unit 220, the substrate liquid processing apparatus 300, and the substrate drying apparatus 400. The transfer robot 244 may include a transfer hand 246 configured to place the substrate W. The transfer hand 246 may move on the guide rail 242 in the first horizontal direction (X direction). For example, the transfer hand 246 may move back and forth along the guide rail 242. In addition, the transfer hand 246 may rotate about the vertical direction (Z direction) as a rotation axis and move in the vertical direction (Z direction).

[0035] In some embodiments, a plurality of transfer hands 246 may be provided. The plurality of transfer hands 246 may be vertically spaced apart. The plurality of transfer hands 246 may move forward, backward, and rotate independently of each other.

[0036] The substrate liquid processing apparatus 300 may perform a liquid processing process that supplies a liquid to the substrate W and performs liquid processing on the substrate W. The substrate drying apparatus 400 may perform a drying process for removing the liquid remaining on the substrate W.

[0037] The substrate liquid processing apparatus 300 and the substrate drying apparatus 400 may perform a substrate cleaning process. For example, the substrate cleaning process may be sequentially performed in the substrate liquid processing apparatus 300 and the substrate drying apparatus 400.

[0038] For example, the substrate liquid processing apparatus 300 may supply a chemical, a cleaning liquid, a rinsing liquid, and / or an organic solvent to the substrate W and process the substrate W. For example, the substrate drying apparatus 400 may perform a drying process for removing the liquid remaining on the surface of the substrate W using a supercritical fluid. The substrate drying apparatus 400 will be described in more detail below.

[0039] Figure 2FIG. 0 schematically shows a cross-sectional view of a substrate drying apparatus 400 according to an embodiment.

[0040] The substrate drying apparatus 400 may include a process chamber 410, a substrate support part 420, a first fluid supply device 431, a first supply pipe 432, a second fluid supply device 441, a second supply pipe 442, a discharge device 451, and a discharge pipe 452.

[0041] The process chamber 410 may provide a processing space PS for processing the substrate W. The process chamber 410 may seal the processing space PS with respect to the outside while processing the substrate W. For example, a state in which the processing space PS is closed may be referred to as a closed state of the process chamber 410, and a state in which the processing space PS is open to the outside atmosphere may be referred to as an open state of the process chamber 410.

[0042] The processing space PS may be defined by a lower surface 411, an upper surface 413, and a side surface 415 of the process chamber 410. In other words, the processing space PS may be defined by a lower wall 410LW including the lower surface 411 of the process chamber 410, an upper wall 410UW including the upper surface 413 of the process chamber 410, and a side wall 410SW defining the side surface 415 of the process chamber 410.

[0043] In some embodiments, the process chamber 410 may include a lower body 410L and an upper body 410U. The upper body 410U may be disposed to be spaced apart from the lower body 410L. The upper body 410U may be coupled to the lower body 410L to cover the lower surface 411 included in the lower body 410L. For example, each of the upper body 410U and the lower body 410L may include, for example, a metallic material.

[0044] In some embodiments, when the upper body 410U is coupled to the lower body 410L, the process chamber 410 may be in a closed state. When the upper body 410U is separated from the lower body 410L, the process chamber 410 may be in an open state. For example, a transition between the closed state and the open state of the process chamber 410 may be achieved by a lifting device (not shown) configured to move the upper body 410U in a vertical direction (Z direction) with respect to the lower body 410L.

[0045] The substrate support part 420 may be disposed in the processing space PS and support the substrate W. The substrate support part 420 may support the substrate W such that the upper surface of the substrate W faces the upper surface 413 of the process chamber 410, and the lower surface of the substrate W faces the lower surface 411 of the process chamber 410.

[0046] In some embodiments, the substrate support portion 420 may have a shape corresponding to the substrate W, such as a disk shape. The substrate support portion 420 may be made of, for example, a metal material or a ceramic material. In some embodiments, the substrate support portion 420 may include an electrostatic chuck that supports the substrate W by electrostatic force or a vacuum chuck that supports the substrate W by negative pressure.

[0047] In some embodiments, the substrate support portion 420 may include a lower structure 420L having a first diameter and an upper structure 420U having a second diameter greater than the first diameter. However, this is a division for convenience of explanation, and the lower structure 420L and the upper structure 420U may be an integral structure and may form the substrate support portion 420.

[0048] The lower structure 420L of the substrate support portion 420 may be supported by support posts 421 located on the lower surface 411 of the process chamber 410. The lower structure 420L of the substrate support portion 420 may be spaced from the lower surface 411 of the process chamber 410 by the height of the support posts 421.

[0049] Support pins 422 may be provided on the upper structure 420U of the substrate support portion 420, and the substrate W is supported by the support pins 422 that contact the lower surface of the substrate W. In some embodiments, the second diameter of the upper structure 420U of the substrate support portion 420 may be smaller than the diameter of the substrate W.

[0050] In some embodiments, the substrate support portion 420 may be disposed above the lower surface 411 of the process chamber 410 to cover the first supply pipe 432. The substrate support portion 420 may be located between the first supply pipe 432 and the substrate W and may be configured to adjust the flow direction of the first fluid PF1 ejected through the first supply pipe 432. The substrate support portion 420 may prevent the first fluid PF1 ejected through the first supply pipe 432 from directly ejecting onto the surface of the substrate W.

[0051] The first fluid supply device 431 may supply the first fluid PF1 to the processing space PS. The first fluid supply device 431 may supply the first fluid PF1 in a gaseous or supercritical state to the process chamber 410. The first fluid PF1 may be supplied to the processing space PS to increase the pressure in the processing space PS.

[0052] For example, the first fluid supply device 431 may supply the first fluid PF1 to the processing space PS during an operation of increasing the pressure in the processing space PS during a substrate drying process. When the pressure in the processing space PS is increased using the first fluid PF1, the dissolution of unnecessary residual liquid may be suppressed, and thus the phenomenon of falling, collapsing, or tilting (hereinafter referred to as the tilting phenomenon) occurring in the fine pattern on the substrate W may be suppressed.

[0053] The first fluid supply device 431 may be connected to a first supply pipe 432 that penetrates the process chamber 410 through a first supply line SL1. The first fluid supply device 431 may inject a first fluid PF1 into the processing space PS through the first supply pipe 432. The first supply pipe 432 may be located in the lower wall 410LW of the process chamber 410. For example, the first supply pipe 432 may penetrate the lower wall 410LW of the process chamber 410.

[0054] In some embodiments, the first supply pipe 432 may extend downward from the lower surface 411 of the process chamber 410. For example, one end of the first supply pipe 432 may be located inside the process chamber 410, and the other end of the first supply pipe 432 may be located outside the process chamber 410. The first fluid supply device 431 may be connected to the other end of the first supply pipe 432.

[0055] In some embodiments, one end of the first supply pipe 432 may overlap with the lower structure 420L in the vertical direction (Z direction). Accordingly, the first fluid PF1 ejected through the first supply pipe 432 is not directly ejected onto the substrate W and can reach the lower structure 420L before the substrate W.

[0056] In some embodiments, the cross-sectional shape of the first supply pipe 432 perpendicular to the extending direction of the first supply pipe 432 may be circular or elliptical. In some embodiments, the cross-sectional shape of the first supply pipe 432 perpendicular to the extending direction of the first supply pipe 432 may also be polygonal (such as square).

[0057] The second fluid supply device 441 may supply a second fluid PF2 to the processing space PS. The second fluid supply device 441 may supply the second fluid PF2 in a supercritical state to the process chamber 410. When the second fluid PF2 in a supercritical state is supplied to the processing space PS, the residual liquid on the substrate W may be dissolved in the second fluid PF2 in a supercritical state. For example, the substrate drying apparatus 400 may dry the substrate W through the second fluid PF2 in a supercritical state.

[0058] The first fluid PF1 may be different from the second fluid PF2. For example, the critical point of the first fluid PF1 may be different from the critical point of the second fluid PF2. In some embodiments, the critical temperature of the first fluid PF1 may be less than the critical temperature of the second fluid PF2.

[0059] When the fluid is in a supercritical state, the physical properties of the fluid (such as density, viscosity, diffusion coefficient, polarity, etc.) change continuously from a gas-like state to a liquid-like state as the pressure changes. When the temperature of the fluid is greater than or equal to the critical temperature and the pressure is greater than or equal to the critical pressure, the fluid becomes in a supercritical state and can have gas-like diffusivity, viscosity, and surface tension, and also have liquid-like solubility.

[0060] Since the second fluid PF2 in the supercritical state has a relatively small surface tension, the second fluid PF2 can penetrate into the fine grooves between the multiple fine patterns of the substrate W. When performing a drying process on the substrate W using the second fluid PF2 in the supercritical state, the residual liquid (such as a cleaning liquid, a rinsing liquid, etc.) remaining on the surface of the substrate W can be removed, and at the same time, the tilting phenomenon occurring in the fine patterns on the substrate W can be suppressed.

[0061] The second fluid supply device 441 can be connected to a second supply pipe 442 penetrating the process chamber 410 through a second supply line SL2. The second fluid supply device 441 can spray the second fluid PF2 into the processing space PS through the second supply pipe 442. The second supply pipe 442 can be located in the upper wall 410UW of the process chamber 410. For example, the second supply pipe 442 can penetrate the upper wall 410UW of the process chamber 410.

[0062] In some embodiments, the second supply pipe 442 can extend upward from the upper surface 413 of the process chamber 410. One end of the second supply pipe 442 can be located inside the process chamber 410, and the other end can be connected to the second fluid supply device 441 outside the process chamber 410.

[0063] In some embodiments, the cross-sectional shape of the second supply pipe 442 perpendicular to the extending direction of the second supply pipe 442 can be circular or elliptical.

[0064] In some embodiments, the cross-sectional shape of the second supply pipe 442 perpendicular to the extending direction of the second supply pipe 442 can also be polygonal (such as square).

[0065] The residual liquid RL on the surface of the substrate W loaded onto the substrate drying device 400 (see Figure 7 ) can include the rinsing liquid, cleaning liquid, and organic solvent remaining after being used during the liquid processing by the substrate liquid processing device 300 (refer to Figure 1 ). For example, the residual liquid can include deionized water (DIW) or isopropyl alcohol (IPA).

[0066] Hereinafter, in this specification, "solubility" refers to the amount of residual liquid dissolved (displaced) in the unit weight of the solvent (the first fluid or the second fluid). For example, the greater the solubility, the faster the residual liquid dissolves (is displaced) in the solvent.

[0067] The solubility of the residual liquid in the first fluid PF1 can be the first solubility, and the solubility of the residual liquid in the second fluid PF2 can be the second solubility.

[0068] The first solubility can be less than the second solubility. For example, the amount of the residual liquid dissolved in every 100 g of the first fluid PF1 provided by the first fluid supply device 431 can be less than the amount of the residual liquid dissolved in every 100 g of the second fluid PF2 provided by the second fluid supply device 441.

[0069] In some embodiments, when the surrounding environment affecting the solubility other than the solvent is the same, the solubility of the residual liquid in the first fluid PF1 can be less than the solubility of the residual liquid in the second fluid PF2. For example, when the surrounding environment affecting the solubility is the same, the temperature of the first fluid PF1 can be the same as the temperature of the second fluid PF2, and the pressure of the first fluid PF1 can be the same as the pressure of the second fluid PF2. However, the surrounding environment affecting the solubility is not limited to temperature and pressure.

[0070] When the first fluid supply device 431 supplies the first fluid PF1 to the processing space PS, a relatively small amount of the residual liquid is dissolved in the first fluid PF1, and when the second fluid supply device 441 supplies the second fluid PF2 to the processing space PS, a relatively large amount of the residual liquid is dissolved in the second fluid PF2.

[0071] In some embodiments, the solubility of the residual liquid in the solvent can increase as the temperature of the solvent increases. For example, in order to inhibit the residual liquid from being dissolved in the first fluid PF1 in the process of supplying the first fluid PF1 to the processing space PS, the first fluid supply device 431 can lower the temperature of the first fluid PF1 until the first fluid PF1 with a pressure greater than the critical pressure becomes a liquid.

[0072] In some embodiments, the first fluid PF1 can include nitrogen (N2), argon (Ar), or a combination thereof. In some embodiments, the second fluid PF2 can include hydrofluoroether (HFE), carbon dioxide (CO2), water (H2O), methane (CH4), ethane (C2H6), propane (C3H8), ethylene (C2H4), propylene (C3H6), methanol (CH3OH), ethanol (C2H5OH), sulfur hexafluoride (SF6), acetone (C3H6O), or a combination thereof.

[0073] In some embodiments, when the first fluid PF1 and the second fluid PF2 are supplied to the processing space PS, the temperature of the first fluid PF1 may be less than or equal to the temperature of the second fluid PF2. For example, the temperature of the second fluid PF2 sprayed into the processing space PS may be about 50°C to about 70°C, and the temperature of the first fluid PF1 sprayed into the processing space PS may be about 0°C to about 50°C.

[0074] The substrate drying apparatus 400 may further include a controller 460. The controller 460 may control the first fluid supply device 431 and the second fluid supply device 441. For example, the controller 460 may control the time for the first fluid supply device 431 to supply the first fluid PF1 and the time for the second fluid supply device 441 to supply the second fluid PF2.

[0075] In some embodiments, the controller 460 may control the first fluid supply device 431 to supply the first fluid PF1 to the processing space PS during an operation of increasing the pressure in the processing space PS. The controller 460 may control the first fluid supply device 431 to supply the first fluid PF1 to the processing space PS until the pressure in the processing space PS reaches a process pressure greater than the initial pressure from the initial pressure. At this time, the controller 460 may control the second fluid supply device 441 not to supply the second fluid PF2 to the processing space PS. That is, the controller 460 may prevent the second fluid PF2 from being sprayed into the processing space PS until the pressure in the processing space PS reaches the process pressure.

[0076] In some embodiments, when the pressure in the processing space PS reaches the process pressure, the controller 460 may control the second fluid supply device 441 to supply the second fluid PF2 to the processing space PS. For example, when the pressure in the processing space PS reaches the process pressure, the controller 460 may spray the second fluid PF2 into the processing space PS and dissolve the residual liquid on the surface of the substrate W in the second fluid PF2.

[0077] In the process of increasing the pressure in the processing space PS, when the upper parts of the plurality of fine patterns of the substrate W are exposed outside the residual liquid, a phenomenon may occur in which the plurality of fine patterns collapse due to the surface tension generated on the surface of the residual liquid located between the plurality of fine patterns. In the process of increasing the pressure in the processing space PS, since the first fluid PF1 fills the processing space PS, relatively little residual liquid can be dissolved. Accordingly, in the process of increasing the pressure in the processing space PS, the phenomenon that some fine patterns of the substrate W are exposed outside the residual liquid can be suppressed, and thus the phenomenon of fine pattern collapse can be suppressed.

[0078] By changing the first fluid PF1 injected into the processing space PS when increasing the pressure in the processing space PS and the second fluid PF2 injected into the processing space PS when removing the residual liquid, the phenomenon of fine pattern collapse of the substrate W can be suppressed.

[0079] In some embodiments, the controller 460 may include: storage devices such as read-only memory (ROM), random access memory (RAM), etc.; and a processor (e.g., a microprocessor, a central processing unit (CPU), a graphics processing unit (GPU), etc.) configured to execute specific operations and algorithms.

[0080] The discharge device 451 may be connected to a discharge pipe 452 penetrating the process chamber 410 through a discharge line EL. The discharge device 451 may discharge the waste liquid DF in the processing space PS to the outside of the process chamber 410 through the discharge pipe 452.

[0081] Here, the waste liquid DF may be defined as a fluid including various gases, chemicals, by-products, particles, etc. in the processing space PS. For example, the waste liquid DF may include the first fluid PF1 and the second fluid PF2 in which the residual liquid is dissolved.

[0082] In some embodiments, the discharge device 451 may include a vacuum pump, a collection unit for collecting the waste liquid DF, and an on / off valve 451_V installed on the discharge line EL. For example, in order to perform a discharge operation through the discharge device 451, the vacuum pump may reduce the pressure in the discharge pipe 452 and suck the waste liquid DF in the processing space PS into the discharge pipe 452. In addition, the discharge device 451 may control the pressure in the processing space PS by sucking and removing the waste liquid DF in the processing space PS.

[0083] In some embodiments, the discharge pipe 452 may penetrate the lower wall 410LW of the process chamber 410. The discharge pipe 452 may extend downward from the lower surface 411 of the process chamber 410. One end of the discharge pipe 452 may be located inside the process chamber 410, and the other end of the discharge pipe 452 may be located outside the process chamber 410.

[0084] The discharge pipe 452 may be connected to the discharge device 451 through the discharge line EL. Through the discharge operation of the discharge device 451, the waste liquid DF in the processing space PS may be sucked into the discharge pipe 452. In some embodiments, the discharge pipe 452 may have a circular or elliptical shape in a plan view. In some embodiments, the discharge pipe 452 may also have a polygonal shape (such as a square) in a plan view.

[0085] Figure 3 Yes Figure 2 Schematic diagram of the first fluid supply device 431 and the second fluid supply device 441 of the substrate drying device 400.

[0086] Refer to Figure 2 and Figure 3 Describe in detail the first fluid supply device 431 and the second fluid supply device 441 of the substrate drying device 400.

[0087] The first fluid supply device 431 may include a first fluid supply tank 3_11, a first condenser 3_13, a first pump 3_50, and a first storage tank 3_15.

[0088] The first fluid supply tank 3_11 may contain raw materials. For example, the first fluid supply tank 3_11 may store the gaseous first fluid PF1. The first condenser 3_13 may change the phase of the first fluid PF. The first condenser 3_13 may cool the first fluid PF1 so that the first fluid PF1 changes from a gaseous state to a liquid state. In some embodiments, when the first fluid PF1 is stored in the first fluid supply tank 3_11 in a high-pressure liquid state, the first condenser 3_13 may be omitted.

[0089] In some embodiments, a filter 3_31 for filtering impurities in the first fluid PF1 and a valve 3_41 for controlling the flow of the first fluid PF1 may be installed on the first pipe 3_21 connecting the first fluid supply tank 3_11 and the first condenser 3_13.

[0090] In some embodiments, the first pump 3_50 may be installed on the second pipe 3_22 between the first condenser 3_13 and the first storage tank 3_15. The first pump 3_50 may drive the first fluid PF1 so that the first fluid PF1 liquefied by the first condenser 3_13 moves along the second pipe 3_22 to the first storage tank 3_15. A filter 3_33 for filtering impurities in the first fluid PF1 and a valve 3_43 for controlling the flow rate of the processing fluid PF may be installed on the second pipe 3_22 connecting the first condenser 3_13 and the first storage tank 3_15.

[0091] The first storage tank 3_15 may store the first fluid PF1 and may change the phase of the first fluid PF1 to a supercritical state. The first storage tank 3_15 may store the first fluid PF1 at a pressure greater than or equal to the critical pressure of the first fluid PF1. The first storage tank 3_15 may heat the first fluid PF1 to a temperature greater than or equal to the critical temperature of the first fluid PF1 through a built-in heater.

[0092] For example, the pressure of the first fluid PF1 stored in the first storage tank 3_15 may be about 170 bar to about 200 bar. The temperature of the first fluid PF1 stored in the first storage tank 3_15 may be about 0 °C to about 5 °C.

[0093] The first fluid PF1 discharged from the first storage tank 3_15 may move along the first supply line SL1 to the first supply pipe 432. In some embodiments, a valve 3_45 for controlling the flow of the first fluid PF1 and a filter 3_35 for filtering impurities in the first fluid PF1 may be installed on the first supply line SL1.

[0094] When the first storage tank 3_15 stores the first fluid PF1 at a pressure greater than the process pressure and when the valve 3_45 installed on the first supply line SL1 is opened, the first fluid PF1 may move to the processing space PS due to the pressure difference between the first storage tank 3_15 and the processing space PS. However, when the first storage tank 3_15 stores the first fluid PF1 at a pressure less than the process pressure, a pump for moving the fluid PF1 from the first storage tank 3_15 to the processing space PS may be additionally installed in the first supply line SL1.

[0095] The second fluid supply device 441 may include a second fluid supply tank 4_11, a second condenser 4_13, a first pump 4_50, and a second storage tank 4_15.

[0096] The second fluid supply tank 4_11 may contain raw materials. For example, the second fluid supply tank 4_11 may store the gaseous second fluid PF2. The second condenser 4_13 may change the phase of the second fluid PF2. The second condenser 4_13 may cool the second fluid PF2 so that the second fluid PF2 changes from a gaseous state to a liquid state. In some embodiments, when the second fluid PF2 is stored in the second fluid supply tank 4_11 in a high-pressure liquid state, the second condenser 4_13 may be omitted.

[0097] In some embodiments, a filter 4_31 for filtering impurities in the second fluid PF2 and a valve 4_41 for controlling the flow rate of the second fluid PF2 may be installed on the first pipe 4_21 connecting the second fluid supply tank 4_11 and the second condenser 4_13.

[0098] In some embodiments, the second pump 4_50 may be installed on the second pipe 4_22 between the second condenser 4_13 and the second storage tank 4_15. The second pump 4_50 may drive the second fluid PF2 so that the second fluid PF2 liquefied by the second condenser 4_13 moves along the second pipe 4_22 to the second storage tank 4_15.

[0099] A filter 4_33 for filtering impurities in the second fluid PF2 and a valve 4_43 for controlling the flow of the processing fluid PF may be installed on the second pipe 4_22 connecting the second condenser 4_13 and the second storage tank 4_15.

[0100] The second storage tank 4_15 can store the second fluid PF2 and phase-transform the second fluid PF2 into a supercritical state. The second storage tank 4_15 can store the second fluid PF2 at a pressure greater than or equal to the critical pressure of the second fluid PF2. The second storage tank 4_15 can heat the second fluid PF2 to a temperature greater than or equal to the critical temperature of the second fluid PF2 through a built-in heater.

[0101] For example, the pressure of the second fluid PF2 stored in the second storage tank 4_15 can be from about 170 bar to about 200 bar. The temperature of the second fluid PF2 stored in the second storage tank 4_15 can be from about 5 °C to about 7 °C.

[0102] In some embodiments, the pressure of the first fluid PF1 stored in the first storage tank 3_15 can be substantially the same as the pressure of the second fluid PF2 stored in the second storage tank 4_15. The temperature of the first fluid PF1 stored in the first storage tank 3_15 can be less than or equal to the temperature of the second fluid PF2 stored in the second storage tank 4_15.

[0103] The second fluid PF2 discharged from the second storage tank 4_15 can move along the second supply line SL2 to the second supply pipe 442. In some embodiments, a valve 4_45 for controlling the flow of the second fluid PF2 and a filter 4_35 for filtering impurities in the second fluid PF2 can be installed on the second supply line SL2.

[0104] When the second storage tank 4_15 stores the second fluid PF2 at a pressure greater than the process pressure and when the valve 4_45 installed on the second supply line SL2 is opened, the second fluid PF2 can move to the processing space PS due to the pressure difference between the second storage tank 4_15 and the processing space PS. However, when the second storage tank 4_15 stores the second fluid PF2 at a pressure less than the process pressure, a pump for moving the second fluid PF2 from the second storage tank 4_15 to the processing space PS can be additionally installed on the second supply line SL2.

[0105] In some embodiments, the controller 460 can control at least one of the valves 3_41, 3_43, and 3_45 of the first fluid supply device 431 to adjust the supply of the first fluid PF1, and can control at least one of the valves 4_41, 4_43, and 4_45 of the second fluid supply device 441 to adjust the supply of the second fluid PF2.

[0106] Figure 4 is a schematic cross-sectional view showing a substrate drying apparatus 400a according to an embodiment.

[0107] Most of the components that make up the substrate drying apparatus 400a described below and the materials of the components are substantially the same or similar to the components and the materials of the components described above with reference to Figure 2 Therefore, for the sake of convenience of explanation, the differences between the substrate drying apparatus 400a to be described in detail and Figure 4 the substrate drying apparatus 400 will be mainly described. Figure 2

[0108] With reference to Figure 4 , the substrate drying apparatus 400a may include a second supply pipe 442a and a discharge pipe 452a.

[0109] The second supply pipe 442a may include a pipe connected to the second fluid supply device 441, and the second fluid PF2 is sprayed into the processing space PS through this pipe. The discharge pipe 452a may include a pipe connected to the discharge device 451, and the waste liquid DF is discharged through this pipe.

[0110] For example, the residual liquid on the surface of the substrate W is dissolved in the second fluid PF2 sprayed into the processing space PS through the second supply pipe 442a, and the second fluid PF2 in which the residual liquid (i.e., a part of the waste liquid DF) is dissolved can be discharged to the outside of the process chamber 410 through the discharge pipe 452a.

[0111] The second supply pipe 442a and the discharge pipe 452a may be spaced apart, with the substrate W therebetween. For example, the second supply pipe 442a and the discharge pipe 452a may be arranged such that the second fluid PF2 ejected from the second supply pipe 442a passes over the upper part of the substrate W and moves to the discharge pipe 452a.

[0112] In some embodiments, the second supply pipe 442a and the discharge pipe 452a may penetrate the side wall 410SW of the process chamber 410. The second supply pipe 442a may extend from the side surface 415 of the process chamber 410 to the outside of the process chamber 410, and the discharge pipe 452a may extend from the side surface 415 of the process chamber 410 to the outside of the process chamber 410.

[0113] In some embodiments, the second supply pipe 442a and the discharge pipe 452a may be spaced apart in the diameter direction of the substrate W. For example, the second supply pipe 442a and the discharge pipe 452a may be symmetric about the center point of the substrate W.

[0114] In some embodiments, the second supply pipe 442a and the discharge pipe 452a may have different vertical heights. For example, the second supply pipe 442a may be located above the substrate support 420, while the discharge pipe 452a may be located below the substrate support 420.

[0115] Figure 5 ​is a flowchart showing a substrate drying method S400 according to an embodiment. Figure 6 is a graph showing the change in the pressure of the processing space PS during substrate drying. Figures 7 to 10 is a cross-sectional view showing the substrate drying method S400 according to the process sequence according to an embodiment.

[0116] Referring to Figure 5 and other drawings, the substrate drying method S400 may include the following operations: loading a substrate W having residual liquid RL on its surface onto a substrate support part 420 (S410); increasing the pressure of the processing space PS by supplying a first fluid PF1 to the processing space PS of the process chamber 410 (S420); dissolving the residual liquid RL located on the substrate W in the second fluid PF2 in a supercritical state by supplying the second fluid PF2 to the processing space PS of the process chamber 410 (S430); discharging the waste liquid DF in the processing space PS to the outside of the process chamber 410 (S440); and unloading the substrate W from the substrate support part 420 (S450).

[0117] Next, referring to Figures 6 to 10 and Figure 2 the substrate drying method S400 of the substrate drying apparatus 400 will be described.

[0118] Referring to Figure 7 , a substrate W having residual liquid RL on its surface can be loaded onto the substrate support part 420. The substrate W may include a plurality of fine patterns W_FP protruding upward from the upper surface of the substrate W. The residual liquid RL may be located between the plurality of fine patterns W_FP, and the plurality of fine patterns W_FP may be completely covered by the residual liquid RL.

[0119] When the substrate W is loaded into the processing space PS, the process chamber 410 may be in an open state. The substrate W may be placed on the substrate support part 420. When the substrate W is placed on the substrate support part 420, the process chamber 410 may be converted from the open state to a closed state so that the processing space PS is sealed from the outside of the process chamber 410.

[0120] Referring to Figure 8 , after the substrate W loading operation, a first fluid PF1 may be supplied to the processing space PS so that the processing space PS is filled with the first fluid PF1. The first fluid supply device 431 may supply the first fluid PF1 in a gaseous or supercritical state to the processing space PS and increase the pressure of the processing space PS from an initial pressure P0 similar to the atmospheric pressure to a process pressure P1 (see Figure 6 ). In some embodiments, the process pressure P1 may be greater than the critical pressure of the first fluid PF1 and may be about 120 bar to about 170 bar.

[0121] In the operation of increasing the pressure in the processing space PS, a small amount of the residual liquid RL may dissolve in the first fluid PF1. However, since the solubility of the residual liquid RL in the first fluid PF1 is relatively low, the plurality of fine patterns W_FP on the substrate W will still be completely covered by the residual liquid RL. For example, the surface of the residual liquid RL will not be located between the plurality of fine patterns W_FP.

[0122] In the operation of increasing the pressure in the processing space PS to the processing pressure P1, by filling the processing space PS with the first fluid PF1 that cannot quickly dissolve the residual liquid RL, the phenomenon that the fine patterns located at the edge of the substrate W among the plurality of fine patterns W_FP are exposed outside the residual liquid RL can be suppressed. Therefore, the phenomenon that the plurality of fine patterns W_FP collapse due to the surface tension of the residual liquid RL can be suppressed.

[0123] In the operation of increasing the pressure in the processing space PS, the second fluid supply device 441 may not supply the second fluid PF2 to the processing space PS. For example, in the operation of increasing the pressure in the processing space PS, when supplying the second fluid PF2 having a relatively high solubility of the residual liquid RL, the phenomenon that the plurality of fine patterns W_FP are exposed outside the residual liquid RL may occur, and thus the phenomenon of damaging the substrate W may occur.

[0124] In some embodiments, the first fluid PF1 may be sprayed into the processing space PS through a first supply pipe 432 that penetrates the lower wall 410LW of the process chamber 410. The first supply pipe 432 overlaps with the substrate support 420 in the vertical direction (Z direction) and may be located below the substrate support 420. Accordingly, the first fluid PF1 ejected from the first supply pipe 432 can fill the processing space PS without directly spraying onto the substrate W.

[0125] In some embodiments, the operation (S420) of increasing the pressure in the processing space PS may include: a first supply operation of supplying the first fluid PF1 at a first temperature to the processing space PS; and a second supply operation of supplying the first fluid PF1 at a second temperature to the processing space PS. In some embodiments, in the first supply operation, the first temperature of the first fluid PF1 may be between about 0°C and about 30°C. In the second supply operation, the second temperature of the first fluid PF1 may be between about 30°C and about 50°C.

[0126] In some embodiments, a first supply operation may be performed until the pressure in the processing space PS reaches a target intermediate pressure between an initial pressure P0 and a process pressure P1. For example, the target intermediate pressure may be between about 60 bar and about 90 bar. When the pressure in the processing space PS reaches the target intermediate pressure through the first supply operation, a second supply operation may be performed. The second supply operation may be performed until the pressure in the processing space PS reaches the process pressure P1.

[0127] Referring Figure 9 , a second fluid PF2 may be supplied to the processing space PS, the residual liquid RL may be dissolved in the second fluid FP2, and the residual liquid RL may be removed from the substrate W.

[0128] When the pressure in the processing space PS reaches the process pressure P1, a second fluid PF2 may be supplied to the processing space PS. The residual liquid RL located on the substrate W may be dissolved in the second fluid PF2 (or replaced by the second fluid PF2).

[0129] In the operation of dissolving the residual liquid RL, the first fluid supply device 431 may not supply the first fluid PF1 to the processing space PS. For example, compared with the second fluid PF2, the solubility of the first fluid PF1 in the residual liquid RL may be lower in the same ambient environment, and thus the efficiency of removing the residual liquid RL may be relatively low. That is, in the operation of dissolving the residual liquid RL, the substrate drying device 400 may supply only the second fluid PF2 to the processing space PS, thereby effectively dissolving the residual liquid RL.

[0130] In some embodiments, the second fluid supply device 441 may supply the second fluid PF2 at a third temperature to the processing space PS. In the operation of dissolving the residual liquid RL, the third temperature of the second fluid PF2 may be greater than or equal to the second temperature of the first fluid PF1 in the second supply operation. For example, in the operation of dissolving the residual liquid RL, the third temperature of the second fluid PF2 may be greater than the critical temperature of the second fluid PF2. In some embodiments, in the operation of dissolving the residual liquid RL, the third temperature of the second fluid PF2 may be between about 50 °C and about 70 °C.

[0131] In some embodiments, the second fluid PF2 may be sprayed into the processing space PS through a second supply pipe 442 that penetrates the upper wall 410UW of the process chamber 410. For example, the second supply pipe 442 may be located above the substrate support 420. Accordingly, the second fluid PF2 may improve the quality of the substrate W by suppressing the phenomenon that impurities generated when the residual liquid RL is dissolved float above the substrate W.

[0132] In some embodiments, in the process of dissolving the residual liquid RL in the second fluid PF2, the following process may be repeated: a pressure reduction process of discharging the second fluid PF2 in which the residual liquid RL is dissolved to the outside of the process chamber 410 and reducing the pressure of the processing space PS from the processing pressure P1 to a discharge pressure P2 less than the processing pressure P1; and a pressure increase process of supplying the second fluid PF2 to the process chamber 410 and increasing the pressure of the processing space PS from the discharge pressure P2 to the processing pressure P1 (see Figure 6 ). In some embodiments, the pressure reduction process and the pressure increase process may be alternately repeated two or more times until the residual liquid RL is removed from the substrate W.

[0133] In some embodiments, in the process of dissolving the residual liquid RL in the second fluid PF2, the second fluid supply device 441 may continuously supply the second fluid PF2 to the processing space PS, and the discharge device 451 may continuously discharge the waste liquid DF from the processing space PS. The speed at which the second fluid supply device 441 supplies the second fluid PF2 may be the same as the speed at which the discharge device 451 discharges the waste liquid DF. Accordingly, the residual liquid RL can be removed from the substrate W while the pressure in the processing space PS remains constant.

[0134] Referring to Figure 10 , when the residual liquid RL is completely removed from the substrate W, the discharge device 451 may discharge the waste liquid DF in the processing space PS and reduce the pressure of the processing space PS to the initial pressure P0. When the pressure of the processing space PS reaches the initial pressure P0, the process chamber 410 may be switched from the closed state to the open state, and the substrate W may be unloaded from the substrate support portion 420.

[0135] So far, the present disclosure has been described with reference to the embodiments shown in the drawings, but these are only exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments can be obtained therefrom. Therefore, the true scope of the technical protection of the present disclosure should be defined by the technical spirit of the appended claims.

[0136] Although the present disclosure has been specifically shown and described with reference to the embodiments of the present disclosure, it should be understood that various changes in form and detail can be made therein without departing from the spirit and scope of the appended claims.

Claims

1. A substrate drying device, comprising: A process chamber including a processing space for drying residual liquid on the surface of a substrate; A substrate support configured to support the substrate within the process chamber; A first fluid supply device configured to supply a first fluid to the processing space through a first supply pipe penetrating the process chamber, wherein the solubility of the residual liquid in the first fluid is a first solubility; A second fluid supply device configured to supply a supercritical second fluid to the processing space through a second supply pipe penetrating the process chamber, wherein the solubility of the residual liquid in the second fluid is a second solubility greater than the first solubility; and A discharge device configured to discharge waste liquid in the processing space of the process chamber to the outside of the process chamber through a discharge pipe penetrating the process chamber.

2. The substrate drying apparatus according to claim 1, wherein, The critical temperature of the first fluid is less than the critical temperature of the second fluid.

3. The substrate drying device according to claim 1, wherein, The temperature of the first fluid when the first fluid supply device supplies the first fluid to the processing space is less than or equal to the temperature of the second fluid when the second fluid supply device supplies the second fluid to the processing space.

4. The substrate drying apparatus according to claim 1, wherein, The first supply pipe penetrates the lower wall of the process chamber and is located below the substrate support.

5. The substrate drying device according to claim 4, wherein, The second supply pipe is located above the substrate support and penetrates the upper wall of the process chamber, and wherein the discharge pipe penetrates the lower wall of the process chamber.

6. The substrate drying device according to claim 1 further comprises: A controller configured to control the first fluid supply device and the second fluid supply device, wherein the controller is configured to: Control the first fluid supply device to supply the first fluid to the processing space of the process chamber until the pressure in the processing space of the process chamber changes from an initial pressure to a process pressure greater than the initial pressure; and When the pressure in the processing space of the process chamber reaches the process pressure, control the second fluid supply device to supply the second fluid to the processing space of the process chamber.

7. A substrate drying method, comprising: Loading a substrate with residual liquid on its surface onto a substrate support within a process chamber; Supplying a first fluid to the processing space within the process chamber and increasing the pressure in the processing space; Supplying a supercritical second fluid to the processing space within the process chamber and dissolving the residual liquid on the surface of the substrate; And Discharging the waste liquid in the processing space to the outside of the process chamber, wherein the solubility of the residual liquid in the first fluid is less than the solubility of the residual liquid in the second fluid.

8. The substrate drying method according to claim 7, wherein, The temperature of the first fluid supplied to the processing space during the operation of increasing the pressure in the processing space is less than or equal to the temperature of the second fluid supplied to the processing space during the operation of dissolving the residual liquid.

9. The substrate drying method according to claim 7, wherein, The substrate includes a plurality of fine patterns protruding upward from the upper surface of the substrate, and wherein, during the operation of loading the substrate onto the substrate support, the residual liquid covers the plurality of fine patterns of the substrate.

10. The substrate drying method according to claim 9, wherein, In the operation of increasing the pressure in the processing space, even if a part of the residual liquid is dissolved in the first fluid, the residual liquid covers the plurality of fine patterns of the substrate.

11. The substrate drying method according to claim 10, wherein, In the operation of increasing the pressure in the processing space, the second fluid is not supplied to the processing space, and only the first fluid is supplied to the processing space.

12. The substrate drying method according to claim 7, wherein, In the operation of dissolving the residual liquid, the first fluid is not supplied to the processing space, and only the second fluid is supplied to the processing space.

13. The substrate drying method according to claim 7, wherein, The first fluid is supplied to the processing space through a first supply pipe located below the substrate support portion and penetrating the lower wall of the process chamber.

14. The substrate drying method according to claim 13, wherein, The second fluid is supplied to the processing space through a second supply pipe located above the substrate support portion and penetrating the side wall of the process chamber, and wherein, the waste liquid is discharged to the outside of the process chamber through a discharge pipe penetrating the side wall of the process chamber and located below the substrate.

15. The substrate drying method according to claim 13, wherein, The second fluid is supplied to the processing space through a second supply pipe located above the substrate support portion and penetrating the upper wall of the process chamber, and wherein, the waste liquid is discharged to the outside of the process chamber through a discharge pipe penetrating the lower wall of the process chamber.

16. The substrate drying method according to claim 7, wherein, The critical point of the first fluid is different from the critical point of the second fluid.

17. The substrate drying method according to claim 16, wherein, The critical temperature of the first fluid is less than the critical temperature of the second fluid.

18. The substrate drying method according to claim 16, wherein, The residual liquid includes isopropyl alcohol C3H8O, wherein, the first fluid includes at least one of nitrogen N2 and argon Ar, and wherein, the second fluid includes at least one of hydrofluoroether HFE and carbon dioxide CO2.

19. A method for drying a substrate, comprising: Loading a substrate having residual liquid on its surface onto a substrate support portion in a process chamber; Supplying a supercritical first fluid to a processing space in the process chamber by a first fluid supply device and increasing the pressure in the processing space; Supplying a supercritical second fluid to the processing space in the process chamber by a second fluid supply device and dissolving the residual liquid on the surface of the substrate in the second fluid; And Discharging the waste liquid in the processing space to the outside of the process chamber, wherein, the substrate includes a plurality of fine patterns protruding upward from the upper surface of the substrate, wherein, in the operation of increasing the pressure in the processing space, the residual liquid covers the plurality of fine patterns of the substrate, wherein, when the pressure in the processing space reaches the process pressure, the second fluid is supplied to the processing space, wherein, the first fluid and the second fluid have different constituent materials, and wherein, the solubility of the residual liquid in the first fluid is less than the solubility of the residual liquid in the second fluid.

20. The substrate drying method according to claim 19, wherein, The residual liquid includes isopropyl alcohol C3H8O, wherein, the first fluid includes at least one of nitrogen N2 and argon Ar, and wherein, the second fluid includes at least one of hydrofluoroether HFE and carbon dioxide CO2.

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