Substrate supercritical treatment device and treatment method

Abstract

The present invention relates to an apparatus for supercritical processing of a substrate and a method for processing a substrate, the apparatus for supercritical processing of a substrate comprising two or more CO2 storage chambers, one or more carbon dioxide supply devices, one or more supercritical processing chambers, and a CO2 recovery device, one carbon dioxide supply device can be connected with one or more than two CO2 storage chambers through a liquid CO2 supply pipeline, and the CO2 storage chambers are connected with the supercritical treatment chamber through a supercritical CO2 supply pipeline; according to the processing device, more than two parallel CO2 storage chambers are arranged, liquid CO2 can be converted into a supercritical CO2 state, in the substrate processing process, CO2 fluid in the supercritical state can be continuously supplied to the subsequent supercritical processing chambers through repeated switching between the CO2 storage chambers, and the CO2 fluid in the supercritical state can be continuously supplied to the subsequent supercritical processing chambers. Therefore, continuous processing of the substrate in the supercritical processing chamber is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit manufacturing industry, and in particular to a substrate / wafer supercritical processing device and processing method. Background Art

[0002] In the manufacturing process of semiconductor wafers and other substrates, their surfaces need to be treated by chemical cleaning or wet etching. If traditional drying methods such as spin drying are used, the liquid in the surface microstructure may cause the pattern to collapse and collapse due to surface tension during the volatilization process. This is especially likely to occur in advanced integrated circuit processes with "high aspect ratio" graphic features. Supercritical fluid drying technology is a technology that completes material drying when the drying medium is at a critical temperature and critical pressure state. When the temperature and pressure of a substance are greater than the critical temperature and critical pressure, the substance will transform into a supercritical state. In the supercritical state, the fluid has the dual characteristics of gas and liquid, and has the high diffusion capacity and low viscosity of gas and the high density and solvation capacity of liquid. Commonly used supercritical fluids include carbon dioxide CO2, nitrogen N2, nitrous oxide N2O, ethylene C2H4, etc. Among them, the most common is CO2, which has a relatively low critical temperature and pressure, is cheap, non-toxic, and has low activity. The critical temperature of CO2 is 31.1℃ and the critical pressure is 7.38MPa. First, the drying medium enters the dried material in a supercritical state and exchanges gently and quickly with the solvent molecules to replace the solvent; then, by changing the temperature, pressure and other conditions, the mixed processing fluid is changed from a supercritical state to a gas, so that the solvent is released from the dried material, thereby achieving the drying effect. Supercritical fluid has the characteristics of low surface tension. The material dried using supercritical fluid drying technology will not shrink or break, and can maintain the structure and state of the dried material to a large extent, effectively preventing the agglomeration and coagulation of the material. It is widely used in many fields such as aerogel drying, medical material preparation, catalyst preparation, and ultrafine material preparation. In the semiconductor field, the use of supercritical fluid to dry the surface of the wafer can effectively prevent the lodging of the microscopic graphics on the surface of the wafer and the collapse of the pattern. In addition to being used for wafer drying, supercritical fluid processing technology can also be used for surface treatment such as cleaning or cleaning the surface of the wafer.

[0003] In order to avoid the collapse of the microscopic patterns on the substrate surface and the collapse of the pattern caused by traditional drying, the technology of supercritical fluid displacement drying is currently used to remove the liquid on the substrate surface and dry the substrate. Samsung-US20230046595A1, Samsung-US11227761B2 uses a gaseous carbon dioxide source, and the gaseous CO2 supplied is liquefied into liquid CO2 by a liquefaction device (Liquefier) ​​and enters the storage chamber (Storage Tank). The storage chamber pre-treats the internal liquid CO2 into a supercritical state-SCC state (SCC: Supercritical Carbondioxide / supercritical CO2, CO2 critical temperature: 31.1°C, critical pressure: 7.38MPa) by heating, and then the CO2 in a supercritical state is passed into the subsequent supercritical processing chamber (processing chamber) to replace the liquid (IPA liquid film, IPA slurry) on the surface of the substrate in the processing chamber to achieve wafer drying. However, the patent only provides one storage chamber for the preparation and storage of supercritical CO2. As the drying process proceeds, when the amount of supercritical CO2 in the chamber is used up to the point where it cannot meet the needs of the subsequent drying process, it is necessary to resupply liquid CO2 to the storage chamber and reprocess it into supercritical CO2 by heating it up for the next round of supercritical drying. This method takes a long time for the system to wait, and it is difficult to meet the needs of high efficiency and high production capacity.

[0004] The carbon dioxide fluid supply device in TEL-CN114496837A and TEL-CN110957239A has the ability to output CO2 under pressure in a supercritical state, and then the CO2 fluid in a supercritical state is passed into the subsequent drying processing chamber through the known structures such as the heater, the throttle valve, and the filter, so as to achieve the replacement of the IPA liquid film on the surface of the substrate in the chamber and the drying of the substrate. In the technical route of TEL, the processing fluid supply device is provided with a circulation passage, which includes a cooling part (such as a compressor and a cooling water system used in conjunction with it), a pump, a heating part (spiral heater), a pressure regulating part (back pressure regulating valve), etc. The entire processing fluid supply device includes many sub-components, resulting in: 1. The movable components such as the compressor and the delivery pump are in contact with CO2, which increases the possibility of particle impurity contamination on the surface of the substrate W, and due to the pulsation of the pump, the pump or the piping may be damaged, or the life of the pump or the piping may be shortened; 2. The system is highly complex and poorly integrated, and it is difficult to integrate into key semiconductor equipment such as cleaning machines. The processing fluid supply device can only be separately arranged at a place far away from the cleaning machine and other equipment, and connected to a dry place through a long connection path. Summary of the invention

[0005] In order to solve the defects existing in the prior art, the object of the present invention is to provide a substrate supercritical treatment device and a treatment method. The treatment device can convert liquid CO2 into supercritical CO2 state by setting two or more parallel CO2 storage chambers, and can continuously supply supercritical CO2 fluid to the subsequent supercritical treatment chamber through repeated switching between the CO2 storage chambers, so as to realize continuous treatment of the substrate / wafers located in the supercritical treatment chamber.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A substrate supercritical treatment device, the treatment device includes a carbon dioxide supply device, a CO2 storage chamber, a supercritical treatment chamber, and a CO2 recovery device;

[0008] There are two or more CO2 storage chambers. An opening and closing valve V2 is provided at the inlet of the CO2 storage chamber. The inlet of the CO2 storage chamber is connected to the outlet of the opening and closing valve V2. An opening and closing valve V3 is provided at the outlet of the CO2 storage chamber. The outlet of the CO2 storage chamber is connected to the inlet of the opening and closing valve V3; preferably, two CO2 storage chambers are provided.

[0009] One or two or more carbon dioxide supply devices are provided. Preferably, two or more carbon dioxide supply devices are provided; an opening and closing valve V1 is provided at the outlet of the carbon dioxide supply device. The outlet of the carbon dioxide supply device is connected to the inlet of the opening and closing valve V1.

[0010] When two or more carbon dioxide supply devices are provided, each carbon dioxide supply device is respectively connected to the inlet of the opening and closing valve V2 at the inlet of one or two or more CO2 storage chambers through the outlet of the opening and closing valve V1 via a liquid CO2 supply pipeline. A first mass flow meter, a first pressure sensor, and a first safety valve are provided on each liquid CO2 supply pipeline;

[0011] Alternatively, when there is one carbon dioxide supply device, the carbon dioxide supply device is connected to each CO2 storage chamber through the opening and closing valve V1, the liquid CO2 supply pipeline and the branch pipeline, and the opening and closing valve V2; one end of the liquid CO2 supply pipeline is connected to the outlet of the opening and closing valve V1, and the other end is respectively connected to the inlet of the opening and closing valve V2 at the inlet of each CO2 storage chamber through the branch pipeline. A first mass flow meter, a first pressure sensor, and a first safety valve are provided on the liquid CO2 supply pipeline.

[0012] A supercritical CO2 supply pipeline and a branch pipeline are provided between the CO2 storage chamber and the supercritical treatment chamber. One end of the supercritical CO2 supply pipeline is connected to the inlet of the supercritical treatment chamber, and the other end is respectively connected to the outlet of the on-off valve V3 at the outlet of each CO2 storage chamber through the branch pipeline of the supercritical CO2 supply pipeline. A second temperature sensor, a filter, a pressure regulating valve V4, and a second mass flowmeter are provided on the supercritical CO2 supply pipeline.

[0013] A third pressure sensor, a third temperature sensor, a heating device H, and a second safety valve are provided on the supercritical treatment chamber. An exhaust pipeline is provided between the supercritical treatment chamber and the CO2 recovery device. One end of the exhaust pipeline is connected to the outlet of the supercritical treatment chamber, and the other end is connected to the inlet of the CO2 recovery device. An on-off valve V5, a pressure regulating valve V6, an on-off valve V7, and a first one-way valve are provided on the exhaust pipeline.

[0014] Furthermore, the CO2 storage chamber is a closed chamber, and its volume can be 2 - 50L, preferably 10 - 40L; the CO2 storage chamber can store liquid CO2, and the stored liquid CO2 is prepared into supercritical CO2 by heating (raising the temperature in the closed storage chamber) or pressurizing with a pressure pump, and then the supercritical CO2 is introduced into the subsequent supercritical treatment chamber. In particular, when one of the CO2 storage chambers supplies supercritical CO2 to the supercritical treatment chamber, the other / other CO2 storage chambers are in the state of liquid inlet (liquid CO2) or preparing supercritical CO2 for standby, and when the supercritical CO2 in the first CO2 storage chamber is exhausted or does not meet the requirements of subsequent process treatment, it is switched to another standby CO2 storage chamber to continue supplying supercritical CO2 to the supercritical treatment chamber. Through the repeated switching of two or more such CO2 storage chambers, continuous supply of supercritical CO2 to the supercritical treatment chamber is achieved without interruption.

[0015] A second pressure sensor and a first temperature sensor are provided on each CO2 storage chamber for monitoring the pressure and temperature in the CO2 storage chamber; each CO2 storage chamber is equipped with a temperature control device; the temperature control device configured for the CO2 storage chamber can be a water bath, an oil bath, an electric heating wire, an electric heating tape, or one or more of other heat transfer devices of cold and hot media, and the temperature adjustment range can be 0 - 150°C.

[0016] Further, the CO2 supply device supplies and outputs liquid CO2, and the temperature of the output liquid CO2 is stabilized at 20 - 25°C; the carbon dioxide supply device can be a high-pressure liquid CO2 storage tank or cylinder, or a liquid CO2 storage tank or cylinder with a transfer pump / high-pressure transfer pump; or a liquid CO2 conversion device composed of a CO2 gas source - gas purifier - flowmeter - filter - condenser, or a liquid CO2 conversion device composed of a CO2 gas source - flowmeter - filter - condenser; the CO2 gas source in the liquid CO2 conversion device provides gaseous CO2 at 5 - 7 MPa, and uses filters, condensers or compressors, etc. to prepare it into liquid CO2. The working temperature of the condenser can be -50 to -10°C, the temperature of the prepared liquid CO2 can be -10 to 10°C, and the pressure of the prepared liquid CO2 can be 3 - 7 MPa; in the latter section of the pipeline of the CO2 supply device, the temperature of the output liquid CO2 can be restored and stabilized at 20 - 25°C under the action of room temperature, or the temperature of the output liquid CO2 can be stabilized at 20 - 25°C through a pipeline heating device.

[0017] A CO2 transfer pump / high-pressure transfer pump can also be provided after the condenser in the liquid CO2 conversion device to increase the ability to output liquid CO2.

[0018] Further, the supercritical treatment chamber is an openable and closable sealed chamber, its volume can be 0.4 - 1.5 L, its material can be high-pressure-resistant metal materials such as stainless steel, the inner wall of the chamber can be treated by electroplating or polishing, etc. One or more trays are provided inside the supercritical treatment chamber, and one substrate or wafer is placed on each tray; the heating device provided on the supercritical treatment chamber can be an electric heating wire, an electric heating tape or an electric heating blanket, etc.

[0019] Further, two branch exhaust pipelines are provided on the exhaust pipeline in parallel with the on-off valve V7 and the one-way valve. One end of one branch exhaust pipeline is connected to the outlet of the pressure regulating valve V6, and the other end is connected to the inlet of the CO2 recovery device through a first throttle valve, an on-off valve V8 and a second one-way valve. One end of the other branch exhaust pipeline is connected to the outlet of the pressure regulating valve V6, and the other end is connected to the inlet of the CO2 recovery device through a second throttle valve and an on-off valve V9.

[0020] Further, the CO2 recovery device can be a CO2 storage tank / storage cylinder, or a CO2 storage tank / storage cylinder including a gas-liquid separation device, a filter and a condenser.

[0021] Further, the first safety valve and the second safety valve are used to relieve the pressure of the system when the pressure of the system is unexpectedly too high, and the pressure relief threshold range of the safety valve is 15 - 30 MPa.

[0022] Further, when there are three or more CO2 storage chambers, the number of supercritical treatment chambers can be increased. For example, four CO2 storage chambers correspond to two supercritical treatment chambers, five CO2 storage chambers correspond to three supercritical treatment chambers, etc., which can further improve the efficiency of substrate treatment.

[0023] Another object of the present invention application is to provide a method for treating a substrate using the above-mentioned substrate supercritical treatment device. The treatment process of this method is as follows:

[0024] (1) Select any one or two CO2 storage chambers to convert liquid CO2 into supercritical state CO2: First, keep the temperature in the selected CO2 storage chamber at the initial temperature (2 - 15 °C) through the temperature control device; then, open the on-off valves V1 and V2 between the carbon dioxide supply device and the selected CO2 storage chamber. Liquid CO2 is supplied to the CO2 storage chamber via the CO2 supply device through the on-off valve V1, on-off valve V2, and the first mass flowmeter. When the volume of liquid CO2 in the CO2 storage chamber (with a volume of V) reaches 0.3 - 0.95V (preferably 0.45 - 0.95V), close the on-off valves V1 and V2; set the temperature of the temperature control device to 35 - 150 °C (preferably 80 - 120 °C), and heat the selected CO2 storage chamber through the temperature control device to convert all the internal CO2 into the supercritical CO2 (SCC) state for standby;

[0025] (2) Place the substrate / wafers to be treated on the tray in the supercritical treatment chamber;

[0026] (3) Preheat the supercritical treatment chamber to 80 - 100 °C in advance. Select any one of the standby CO2 storage chambers, open the on-off valve V3 between the selected CO2 storage chamber and the supercritical treatment chamber. The supercritical CO2 in the CO2 storage chamber enters the supercritical treatment chamber through the filter, pressure regulating valve V4, and the second mass flowmeter to treat the substrate / wafers. After the treatment is completed, the supercritical treatment chamber exhausts and relieves pressure, takes out the treated substrate / wafers, and transfers in new substrates / wafers to be treated for treatment;

[0027] (4) While performing any one of the processes in step (1) or (2) or (3), complete the conversion of liquid CO2 in at least one other CO2 storage chamber into the supercritical CO2 state according to the operation in step (2) to make the other CO2 storage chambers enter the standby state;

[0028] (5) During the substrate processing, when the pressure in the operating CO2 storage chamber drops to 10 - 25 MPa, close the on-off valve V3 between the operating CO2 storage chamber and the supercritical processing chamber, and at the same time open the on-off valve V3 between any standby CO2 storage chamber and the supercritical processing chamber to achieve the switching between CO2 storage chambers, and use the switched CO2 storage chamber to supply the supercritical processing chamber SCC.

[0029] Further, the substrate / wafers processing in step (3) is as follows: Supercritical CO2 enters the supercritical processing chamber, and the supercritical processing chamber enters the air intake and pressure boosting process, which is called the T1 pressure boosting stage. When the pressure inside the supercritical processing chamber rises to 8 - 18 MPa (preferably 15 - 18 MPa), close the on-off valve V3 and stop supplying SCC. The T1 pressure boosting stage ends and enters the T2 standing stage. The pressure in the supercritical processing chamber stabilizes at 8 - 18 MPa and remains for 1 - 60 s, and the substrate / wafer makes full contact and replacement with the supercritical CO2. The T2 standing stage ends. At the same time, open the on-off valve V3 between the CO2 storage chamber and the supercritical processing chamber, the pressure regulating valve V4, the on-off valve V5, the pressure regulating valve V6, the on-off valve V7 and the check valve on the exhaust pipeline to enter the T3 circulation replacement stage. In this stage, the opening degree of the pressure regulating valve V6 is feedback-regulated through the control system so that the pressure in the supercritical processing chamber always remains at 8 - 18 MPa (preferably 14 - 18 MPa) for 0.5 - 2 min; the substrate wafer processing is completed, close the on-off valve V3 and the pressure regulating valve V4 between the CO2 storage chamber and the supercritical processing chamber, and the T3 circulation replacement stage ends. The supercritical processing chamber enters the T4 exhaust stage, and the supercritical processing chamber is exhausted and depressurized through the exhaust pipeline until the pressure inside the supercritical processing chamber drops to atmospheric pressure; the above processing process may or may not include the T2 standing stage.

[0030] Further, the T3 circulation replacement stage can be a stable replacement process with constant pressure, a pressure reduction - pressure boosting cycle process, a pressure reduction - standing - pressure boosting cycle process, or a pressure reduction - pressure boosting - standing cycle process, or one or more of them.

[0031] Further, the above processing method can be used for the processing of drying, cleaning, washing, etc. of the substrate / wafer. A liquid film can be coated on the surface of the substrate / wafer before supercritical processing. The liquid film is one or more of alcohol-based and alkane-based liquid films, such as isopropyl alcohol liquid film, and the thickness of the liquid film can be 0.05 - 0.5 mm, for example, 0.1 mm.

[0032] Compared with the prior art, the advantages of the present invention are as follows: 1. By switching two or more CO2 storage chambers, continuous and uninterrupted supply of supercritical CO2 to the processing chamber can be achieved, meeting the requirements of high production capacity and high processing efficiency; 2. In the CO2 supply device, mechanical components with a large pressure variation range such as a pressure pump do not need to be set, the system structure is simple, the cost is low, it is not easily damaged, and it is more conducive to later maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 FIG. is a schematic structural diagram of a substrate supercritical processing device provided by the present invention; wherein a is that the carbon dioxide supply device is provided with more than 2; b is that the carbon dioxide supply device is provided with 1.

[0034] Figure 2 FIG. is a schematic structural diagram of a substrate supercritical processing device provided in Embodiment 1, wherein a is that the O2 storage chamber 200a completes the conversion of liquid CO2 to the supercritical state, and b is that the CO2 storage chamber 200b completes the conversion of liquid CO2 to the supercritical state.

[0035] Figure 3 FIG. is a schematic structural diagram of a substrate supercritical processing device provided in Embodiment 2, wherein a is that the CO2 storage chamber 200a completes the conversion of liquid CO2 to the supercritical state, and b is that the CO2 storage chamber 200b completes the conversion of liquid CO2 to the supercritical state..

[0036] Figure 1 、 Figure 2 and Figure 3 In, 100 - CO2 supply device, 401 - on - off valve V1, 402 - liquid CO2 supply pipeline, 403 - first mass flowmeter, 404 - on - off valve V2, 405 - first pressure sensor, 406 - first safety valve, 407 - first temperature sensor, 408 - second pressure sensor, 20 - CO2 storage chamber, 200 - temperature control device, 409 - second temperature sensor, 410 - filter, 411 - supercritical CO2 supply pipeline, 412 - on - off valve V3, 413 - pressure regulating valve V4, 414 - second mass flowmeter, 415 - third temperature sensor, 416 - third pressure sensor, 417 - substrate / wafer, 418 - heating device, 419 - second safety valve, 40 - supercritical processing chamber, 420 - on - off valve V5, 421 - pressure regulating valve V6, 422 - exhaust pipeline, 423 - on - off valve V7, 424 - first check valve, 425 - first throttle valve, 426 - on - off valve V8, 427 - second check valve, 428 - second throttle valve, 429 - on - off valve V9, 300 - CO2 recovery device.

[0037] Figure 4Schematic structural diagram of the carbon dioxide supply device 100 used in Example 1 and Example 2, where 10 is the CO2 gas source, 11 is the mass flow meter, 12 is the filter, and 13 is the condenser.

[0038] Figure 5 Schematic structural diagram of the CO2 recovery device 300 used in Example 1 and Example 2, where 30 is the end pipeline of the CO2 exhaust line, 31 is the gas-liquid separation device, 32 is the filter, 33 is the condenser, and 34 is the CO2 storage tank.

[0039] Figure 6 Temperature control device configured for the CO2 storage chamber in Example 1 and Example 2, where 20 is the CO2 storage chamber, 21 is the water bath temperature controller, 22 is the water bath delivery pipeline, 23 is the water bath coil, 24 is the electric heating wire, and 25 is the water bath tank.

[0040] Figure 7 Graph showing the pressure changes at each of the stages T1, T2, T3, and T4 in the supercritical treatment chamber during the drying process of the wafer by the substrate supercritical treatment device in Example 3.

[0041] Figure 8 Graph showing the pressure changes at the stages T1, T3, and T4 in the supercritical treatment chamber during the drying process of the wafer by the substrate supercritical treatment device in Example 4.

[0042] Figure 9 Overall process flow chart of the present invention for processing the substrate using the substrate supercritical treatment device. Detailed implementation mode

[0043] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] As Figure 2 shown, a substrate supercritical treatment device includes two carbon dioxide supply devices 100a and 100b, two CO2 storage chambers 20a and 20b, a supercritical treatment chamber 40, and a CO2 recovery device 300;

[0046] An on-off valve 401a is provided at the outlet of the carbon dioxide supply device 100a. The outlet of the carbon dioxide supply device 100a is connected to the inlet of the on-off valve 401a. An on-off valve 404a is provided at the inlet of the CO2 storage chamber 20a. The inlet of the CO2 storage chamber 20a is connected to the outlet of the on-off valve 404a. One end of the liquid CO2 supply pipeline 402a is connected to the outlet of the on-off valve 401a, and the other end is connected to the inlet of the on-off valve 404a. A first mass flowmeter 403a, a first pressure sensor 405a, and a first safety valve 406a are provided on the liquid CO2 supply pipeline 402a;

[0047] An on-off valve 401b is provided at the outlet of the carbon dioxide supply device 100b. The outlet of the carbon dioxide supply device 100b is connected to the inlet of the on-off valve 401b. An on-off valve 404b is provided at the inlet of the CO2 storage chamber 20b. The inlet of the CO2 storage chamber 20b is connected to the outlet of the on-off valve 404b. One end of the liquid CO2 supply pipeline 402b is connected to the outlet of the on-off valve 401b, and the other end is connected to the inlet of the on-off valve 404b. A first mass flowmeter 403b, a first pressure sensor 405b, and a first safety valve 406b are provided on the liquid CO2 supply pipeline 402b;

[0048] Among them, the carbon dioxide supply devices 100a and 100b are liquid CO2 conversion devices composed of a gaseous CO2 cylinder - mass flowmeter - filter - condenser (as Figure 4 shown). The gaseous CO2 cylinder outputs gaseous CO2 at 5 MPa. The mass flowmeter is a Coriolis mass flowmeter. The operating temperature of the condenser can be -30 °C. The output liquid CO2 warms up to room temperature in the output pipeline, and the pressure of the output liquid CO2 is 6 MPa.

[0049] A second pressure sensor 408a and a first temperature sensor 407a are provided on the CO2 storage chamber 20a. An on-off valve 412a is provided at the outlet of the CO2 storage chamber 20a. The outlet of the CO2 storage chamber 20a is connected to the inlet of the on-off valve 412a; A second pressure sensor 408b and a first temperature sensor 407b are provided on the CO2 storage chamber 20b. An on-off valve 412b is provided at the outlet of the CO2 storage chamber 20b. The outlet of the CO2 storage chamber 20b is connected to the inlet of the on-off valve 412b; Both the CO2 storage chambers 20a and 20b are cylindrical sealed chambers with a volume of 30 L. The CO2 storage chamber 20a is equipped with a temperature control device 200a. The temperature control device 200a includes a water bath temperature controller 21, a water bath delivery pipeline 22, a water bath coil 23, an electric heating wire 24, and a water bath tank 25.

[0050] The supercritical processing chamber 40 is a hollow, airtight stainless-steel chamber with an internal volume of 0.7 L. Inside, there is a tray for placing substrates / wafers. The inlet of the supercritical processing chamber 40 is connected to one end of the supercritical CO2 supply pipeline 411. The other end of the CO2 supply pipeline 411 is branched into two branch pipelines through a three-way joint and is respectively connected to the outlets of the on-off valves 412a and 412b. On the supercritical CO2 supply pipeline 411, there are a second temperature sensor 409, a filter 410, a pressure regulating valve 413, and a second mass flowmeter 414. The first mass flowmeters 403a, 403b, and the second mass flowmeter 414 are all Coriolis mass flowmeters.

[0051] At the bottom of the supercritical processing chamber 40, there is an electric heating sheet 418. On the supercritical processing chamber 40, there are a third pressure sensor 416 and a third temperature sensor 415 for detecting the pressure and temperature inside the chamber. On the supercritical processing chamber 40, there is a second safety valve 419. The outlet of the supercritical processing chamber 40 is connected to one end of the exhaust pipeline 422, and the other end of the exhaust pipeline 422 is connected to the inlet of the CO2 recovery device 300. On the exhaust pipeline 422, there are an on-off valve 420, a pressure regulating valve 421, an on-off valve 423, and a check valve 424.

[0052] The CO2 recovery device 300 consists of a gas-liquid separation tank, a filter, a condenser, and a CO2 storage tank.

[0053] Example 2

[0054] As Figure 2 shown, a substrate supercritical processing device includes one carbon dioxide supply device 100, two CO2 storage chambers 20a and 20b, a supercritical processing chamber 40, and a CO2 recovery device 300. The carbon dioxide supply device 100 is respectively connected to the two CO2 storage chambers 20a and 20b through the liquid CO2 supply pipeline 402.

[0055] An on-off valve 401 is provided at the outlet of the carbon dioxide supply device 100, and the outlet of the carbon dioxide supply device 100 is connected to the inlet of the on-off valve 401. An on-off valve 404a is provided at the inlet of the CO2 storage chamber 20a, and the inlet of the CO2 storage chamber 20a is connected to the outlet of the on-off valve 404a. An on-off valve 404b is provided at the inlet of the CO2 storage chamber 20b, and the inlet of the CO2 storage chamber 20b is connected to the outlet of the on-off valve 404b.

[0056] A liquid CO₂ supply pipeline 402 is provided between the carbon dioxide supply device 100 and the CO₂ storage chambers 20a and 20b. One end of the liquid CO₂ supply pipeline 402 is connected to the outlet of the on-off valve 401, and the other end is branched into two branch pipelines through a tee joint and is respectively connected to the inlets of the on-off valves 404a and 404b. A first mass flowmeter 403, a first pressure sensor 405, and a first safety valve 406 are arranged on the liquid CO₂ supply pipeline 402;

[0057] Among them, the carbon dioxide supply devices 100a and 100b are liquid CO₂ conversion devices composed of a gaseous CO₂ cylinder - mass flowmeter - filter - condenser (as Figure 4 shown). The gaseous CO₂ cylinder outputs gaseous CO₂ at 5 MPa. The mass flowmeter is a Coriolis mass flowmeter. The operating temperature of the condenser can be -30 °C. The prepared liquid CO₂ warms up to room temperature in the output pipeline, and the output pressure of the liquid CO₂ is 6 MPa.

[0058] A second pressure sensor 408a and a first temperature sensor 407a are arranged on the CO₂ storage chamber 20a. An on-off valve 412a is arranged at the outlet of the CO₂ storage chamber 20a, and the outlet of the CO₂ storage chamber 20a is connected to the inlet of the on-off valve 412a; A second pressure sensor 408b and a first temperature sensor 407b are arranged on the CO₂ storage chamber 20b. An on-off valve 412b is arranged at the outlet of the CO₂ storage chamber 20b, and the outlet of the CO₂ storage chamber 20b is connected to the inlet of the on-off valve 412b; Both the CO₂ storage chambers 20a and 20b are cylindrical sealed chambers with a volume of 30 L. The CO₂ storage chamber 20a is configured with a temperature control device 200a, and the temperature control device 200a includes a water bath temperature controller 21, a water bath delivery pipeline 22, a water bath coil 23, an electric heating wire 24, and a water bath tank 25.

[0059] The supercritical treatment chamber 40 is a hollow, stainless steel sealed cavity with a volume of 0.7 L. An internal tray for placing substrates / wafers is provided. The inlet of the supercritical treatment chamber 40 is connected to one end of the supercritical CO₂ supply pipeline 411. The other end of the CO₂ supply pipeline 411 is branched into two branch pipelines through a tee joint and is respectively connected to the outlets of the on-off valves 412a and 412b; A second temperature sensor 409, a filter 410, a pressure regulating valve 413, and a second mass flowmeter 414 are arranged on the supercritical CO₂ supply pipeline 411. The first mass flowmeters 403a, 403b, and the second mass flowmeter 414 are all Coriolis mass flowmeters.

[0060] The bottom of the supercritical treatment chamber 40 is provided with an electric heating belt 418. A third pressure sensor 416 and a third temperature sensor 415 are provided on the supercritical treatment chamber 40 for detecting the pressure and temperature inside the chamber. A second safety valve 419 is provided on the supercritical treatment chamber 40. The outlet of the supercritical treatment chamber 40 is connected to one end of the exhaust pipeline 422, and the other end of the exhaust pipeline 422 is connected to the inlet of the CO2 recovery device 300. An on-off valve 420, a pressure regulating valve 421, an on-off valve 423, and a check valve 424 are provided on the exhaust pipeline 422. The CO2 recovery device 300 is composed of a gas-liquid separation tank, a filter, a condenser, and a CO2 storage tank.

[0061] Example 3

[0062] The 12-inch wafer is dried using the supercritical treatment device in Example 1. The specific process is as follows:

[0063] First, check that all components of the supercritical treatment device are in normal condition and all valves are in the closed state;

[0064] (1) Turn on the heating device 418, preheat the supercritical treatment chamber 40 to 90 °C in advance and maintain this temperature;

[0065] (2) Set the temperature of the temperature control device 200a to 5 °C, adjust and maintain the temperature of the CO2 storage chamber 20a at the initial temperature of 5 °C. Then, open the on-off valve 401a and the on-off valve 404a, and the liquid CO2 output by the CO2 supply device 100a passes through the liquid CO2 supply pipeline 402a and is successively transported to the CO2 storage chamber 20a through the on-off valve 401a, the first mass flowmeter 403a, and the on-off valve 404a. When the liquid CO2 in the CO2 storage chamber 20a reaches 15 L, close the on-off valve 401a and the on-off valve 404a, set the temperature of the temperature control device 200a to 90 °C, heat the CO2 storage chamber 20a, and monitor the temperature and pressure inside the CO2 storage chamber 20a through the first temperature sensor 407a and the second pressure sensor 408a. When the temperature reaches 90 °C and the pressure reaches 20 MPa, at this time, all the CO2 inside the CO2 storage chamber 20a becomes in the supercritical state (SCC state), as Figure 2 shown in a.

[0066] (3) Place a 12-inch wafer with a liquid film of IPA (isopropyl alcohol) coated on its surface on the tray in the supercritical treatment chamber.

[0067] (4) Open the on-off valve 412a and the pressure regulating valve 413. The SCC in the CO2 storage chamber 20a sequentially passes through the on-off valve 412a, the filter 410, the pressure regulating valve 413, and the second mass flowmeter 414 and enters the supercritical treatment chamber 40. The air pressure in the supercritical treatment chamber 40 will start to rise from atmospheric pressure; the process of increasing the intake air pressure in the supercritical treatment chamber 40 is called the T1 pressure increase stage (as Figure 7 shown). When the pressure in the supercritical treatment chamber 40 rises to the supercritical treatment pressure P1 = 16 MPa; close the on-off valve 412a and the pressure regulating valve 413, stop supplying SCC, and the T1 pressure increase stage ends. Enter the T2 static stage. The pressure in the supercritical treatment chamber 40 stabilizes at 16 MPa and remains for 10 s. During the T2 static stage, the SCC in the supercritical treatment chamber 40 will displace the IPA liquid film on the wafer surface, and the IPA liquid film on the substrate surface will gradually dissolve in the SCC; at the end of the T2 static stage, open the on-off valve 412a, the pressure regulating valve 413, the on-off valve 420, the pressure regulating valve 421, the on-off valve 423, and the check valve 424. The processing enters the T3 circulation displacement stage. The control system feedback-regulates the opening of the pressure regulating valve 421 according to the pressure data detected by the pressure sensor 416, so that the pressure in the supercritical treatment chamber 40 always remains at P1 = 16 MPa. During the T3 circulation displacement stage, the supercritical treatment chamber 40 discharges the mixed fluid containing IPA through the exhaust pipeline 422, and the discharged mixed fluid finally flows into the recovery device 300 for recovery treatment. During the T3 circulation displacement stage, the on-off valve 412a and the pressure regulating valve 413 always remain open, so as to continuously supply fresh and pure SCC to the supercritical treatment chamber 40. By supplying SCC to the supercritical treatment chamber 40 while discharging the mixed treatment fluid, the replacement and drying treatment of IPA on the wafer surface are realized, and the pressure in the supercritical treatment chamber 40 is maintained at 16 MPa, so as to ensure that the mixed fluid is always in the supercritical state and no local gas-liquid phase change process will occur. The T3 circulation displacement stage lasts for 1 min, and the IPA on the wafer surface is completely replaced by the supercritical fluid, and the drying treatment of the wafer surface is completed. Close the on-off valve 412a and the pressure regulating valve 413, and the T3 circulation displacement stage ends. The supercritical treatment chamber 40 enters the T4 exhaust stage. The treatment fluid in the supercritical treatment chamber 40 is discharged through the exhaust line until the pressure inside it drops to atmospheric pressure; take out the dried wafer and transfer a new wafer with an IPA liquid film on its surface for the next supercritical fluid drying treatment.

[0068] (5) While starting the drying process of the wafer in the supercritical treatment chamber 40, set the temperature of the temperature control device 200b to 5°C. The temperature of the CO2 storage chamber 20b is maintained at the initial temperature of 5°C under the action of the temperature control device 200b. Then, open the on-off valve 401b and the on-off valve 404b. The liquid CO2 in the carbon dioxide supply device 100b is transported to the CO2 storage chamber 20b through the liquid CO2 supply pipeline 402b in sequence, passing through the on-off valve 401b, the first mass flowmeter 403b, and the on-off valve 404b. When the liquid CO2 in the CO2 storage chamber 20b reaches 15L, close the on-off valve 401 and the on-off valve 404b. Set the temperature of the temperature control device 200b corresponding to the CO2 storage chamber 20b to 90°C and heat the CO2 storage chamber 20b. Monitor the temperature and pressure in the CO2 storage chamber 20b through the first temperature sensor 407b and the second pressure sensor 408b. When the temperature reaches 90°C and the pressure reaches 20 MPa; at this time, all the CO2 inside the CO2 storage chamber 20b becomes in the supercritical state (SCC state), and the CO2 storage chamber 20b enters the standby state (as Figure 2 shown in b);

[0069] (6) When the pressure in the supercritical treatment chamber 40a drops to less than 16 MPa, close the on-off valve 412a, and at the same time open the on-off valve 412b. Supply SCC from the CO2 storage chamber 20b to the supercritical treatment chamber 40, realizing the switching between the CO2 storage chambers and continuously supplying SCC to the supercritical treatment chamber 40.

[0070] Example 4

[0071] Use the supercritical treatment device in Example 1 to dry a 12-inch wafer.

[0072] This example is a variant based on Example 3. The specific process is the same as that of Example 3, except that the pressure change process in the supercritical treatment chamber in step (4) of this example adopts a pressure reduction - pressure increase cycle process (as Figure 8 shown), specifically as follows:

[0073] (4) Open the on-off valve 412a and the pressure regulating valve 413. The SCC in the CO2 storage chamber 20a sequentially passes through the on-off valve 412a, the filter 410, the pressure regulating valve 413, and the second mass flowmeter 414 and enters the supercritical treatment chamber 40. The air pressure in the supercritical treatment chamber 40 will start to rise from atmospheric pressure; the air intake and pressure increase process in the supercritical treatment chamber 40 is called the T1 pressure increase stage (as Figure 8As shown, when the pressure in the supercritical treatment chamber 40 rises to the supercritical treatment pressure P1 = 16 MPa, the opening and closing valve 412a and the pressure regulating valve 413 are closed, the supply of SCC is stopped, and the T1 pressure boosting stage ends. Then, it enters the T3 circulation replacement stage. At the same time, the opening and closing valve 420, the pressure regulating valve 421, the opening and closing valve 423, and the one-way valve 424 are opened to discharge part of the mixed treatment fluid. The pressure in the supercritical treatment chamber 40 will decrease as the treatment fluid is discharged. When the pressure in the supercritical treatment chamber 40 drops to P2 = 14 MPa, the opening and closing valve 420 and the pressure regulating valve 423 are closed. At the same time, the opening and closing valve 412a and the pressure regulating valve 413 are opened, and the pressure in the supercritical treatment chamber 40 will rise as the SCC is replenished. When the pressure in the supercritical treatment chamber 40 rises to P1 = 16 MPa, the opening and closing valve 412a and the pressure regulating valve 413 are closed again, and part of the mixed treatment fluid is discharged. Then, the cycle process of pressure reduction - pressure boost in the supercritical treatment chamber 40 is carried out in turn. In each pressure reduction process, the mixed treatment fluid dissolved with IPA is discharged, and in each pressure boost process, fresh and pure SCC is replenished to replace the IPA liquid film on the wafer surface and dry the wafer. The cycle process is carried out under the feedback control of the control system. The control system can feedback and adjust the opening and closing of each opening and closing door and the opening degree of the pressure regulating valve according to the pressure data detected by the pressure sensor 416. The pressure reduction - pressure boost process is cycled 7 times (taking 1 minute), and the T3 circulation replacement stage ends. The opening and closing valve 412a and the pressure regulating valve 413 are closed, and the opening and closing valve 420, the pressure regulating valve 421, the opening and closing valve 423, and the one-way valve 424 are opened. The supercritical treatment chamber 40 enters the T4 exhaust stage, and the treatment fluid in the supercritical treatment chamber 40 is discharged through the exhaust line until the pressure inside it drops to atmospheric pressure; the dried wafer is taken out, and a new wafer with an IPA liquid film on its surface is introduced for the next supercritical fluid drying treatment.

[0074] Reasonable deformations or changes based on this patent and the embodiments should also be within the protection scope of this patent. For example, increasing the number of supercritical treatment chambers, with four CO2 storage chambers corresponding to two supercritical treatment chambers, six CO2 storage chambers corresponding to three supercritical treatment chambers, and so on.

Claims

1. A substrate supercritical treatment device, comprising a carbon dioxide supply device, a CO2 storage chamber, a supercritical treatment chamber, and a CO2 recovery device, characterized in that there are more than 2 CO2 storage chambers, an opening and closing valve V2 is arranged at the inlet of the CO2 storage chamber, the inlet of the CO2 storage chamber is connected to the outlet of the opening and closing valve V2, an opening and closing valve V3 is arranged at the outlet of the CO2 storage chamber, and the outlet of the CO2 storage chamber is connected to the inlet of the opening and closing valve V3; each CO2 storage chamber is equipped with a temperature control device; one or more than 2 carbon dioxide supply devices are arranged, preferably more than 2 carbon dioxide supply devices are arranged; an opening and closing valve V1 is arranged at the outlet of the carbon dioxide supply device, and the outlet of the carbon dioxide supply device is connected to the inlet of the opening and closing valve V1; when there are more than 2 carbon dioxide supply devices, each carbon dioxide supply device is respectively connected to the inlet of the opening and closing valve V2 at the inlet of one or more than two CO2 storage chambers through the outlet of the opening and closing valve V1 via a liquid CO2 supply pipeline, and a first mass flowmeter, a first pressure sensor, and a first safety valve are arranged on the liquid CO2 supply pipeline; or, when there is 1 carbon dioxide supply device, the carbon dioxide supply device is respectively connected to each CO2 storage chamber through the opening and closing valve V1, the liquid CO2 supply pipeline and the branch pipeline, and the opening and closing valve V2; one end of the liquid CO2 supply pipeline is connected to the outlet of the opening and closing valve V1, and the other end is respectively connected to the inlet of the opening and closing valve V2 at the inlet of each CO2 storage chamber through the branch pipeline. A first mass flowmeter, a first pressure sensor, and a first safety valve are arranged on the liquid CO2 supply pipeline; a supercritical CO2 supply pipeline is arranged between the CO2 storage chamber and the supercritical treatment chamber. One end of the supercritical CO2 supply pipeline is connected to the inlet of the supercritical treatment chamber, and the other end is respectively connected to the outlet of the opening and closing valve V3 at the outlet of each CO2 storage chamber through the branch pipeline of the supercritical CO2 supply pipeline. A second temperature sensor, a filter, a pressure regulating valve V4, and a second mass flowmeter are arranged on the supercritical CO2 supply pipeline; an exhaust pipeline is arranged between the supercritical treatment chamber and the CO2 recovery device. One end of the exhaust pipeline is connected to the outlet of the supercritical treatment chamber, and the other end is connected to the inlet of the CO2 recovery device. An opening and closing valve V5, a pressure regulating valve V6, an opening and closing valve V7, and a first one-way valve are arranged on the exhaust pipeline.

2. The treatment device according to claim 1, characterized in that a second pressure sensor and a first temperature sensor are arranged on the CO2 storage chamber for monitoring the pressure and temperature in the CO2 storage chamber; the volume of the CO2 storage chamber can be 2 - 50L, preferably 10 - 40L; the temperature control device configured for the CO2 storage chamber can be one or more than two of a water bath box, an oil bath box, an electric heating wire, an electric heating tape, or other heat exchange devices of cold and hot media, and the temperature adjustment range can be 0 - 150°C.

3. The device according to claim 2, characterized in that The CO2 supply device supplies and outputs liquid CO2, and the temperature of the output liquid CO2 is stabilized at 20-25°C; the carbon dioxide supply device can be a high-pressure liquid CO2 storage tank or cylinder, or a liquid CO2 storage tank or cylinder with a transfer pump / high-pressure transfer pump; or a liquid CO2 conversion device composed of a CO2 gas source - gas purifier - flowmeter - filter - condenser, or a liquid CO2 conversion device composed of a CO2 gas source - flowmeter - filter - condenser; a CO2 transfer pump / high-pressure transfer pump can be provided in the liquid CO2 conversion device.

4. The processing device according to claim 1, wherein The supercritical processing chamber is an openable and closable sealed chamber, and its volume can be 0.4-1.5L. A third pressure sensor, a third temperature sensor, a heating device and a second safety valve are provided on the supercritical processing chamber. One or more trays are provided inside the supercritical processing chamber, and each tray can hold a substrate or wafer. The heating device provided on the supercritical processing chamber can be an electric heating wire, an electric heating tape or an electric heating blanket.

5. The processing device according to claim 1, wherein Two branch exhaust gas pipelines are provided on the exhaust gas pipeline in parallel with the on-off valve V7 and the one-way valve. One end of one branch exhaust gas pipeline is connected to the outlet of the pressure regulating valve V6, and the other end is connected to the inlet of the CO2 recovery device through a first throttle valve, an on-off valve V8 and a second one-way valve. One end of the other branch exhaust gas pipeline is connected to the outlet of the pressure regulating valve V6, and the other end is connected to the inlet of the CO2 recovery device through a second throttle valve and an on-off valve V9.

6. The processing device according to claim 1, characterized in that The first safety valve and the first safety valve are used to relieve the pressure of the system when the pressure of the system is unexpectedly too high, and the pressure relief threshold range of the safety valve is 15-30 MPa.

7. A method for processing a substrate using the substrate supercritical processing apparatus according to any one of claims 1-6, characterized in that, The method specifically includes the following steps: (1) Select any one or two CO2 storage chambers to convert liquid CO2 into supercritical state CO2: First, keep the temperature in the selected CO2 storage chamber at the initial temperature (2-15°C) through the temperature control device; then, open the on-off valves V1 and V2 between the carbon dioxide supply device and the selected CO2 storage chamber, and the liquid CO2 is supplied to the CO2 storage chamber through the CO2 supply device, on-off valve V1, on-off valve V2 and the first mass flowmeter. When the volume of the liquid CO2 in the CO2 storage chamber (with a volume of V) reaches 0.3-0.95V (preferably 0.45-0.95V), close the on-off valves V1 and V2; set the temperature of the temperature control device to 35-150°C (preferably 80-120°C), and heat the selected CO2 storage chamber through the temperature control device to convert all the internal CO2 into the supercritical CO2 (SCC) state for standby. (2) Place the substrate to be processed on the tray of the supercritical processing chamber. (3) The supercritical treatment chamber is preheated to 80 - 100 °C in advance. Select any one of the standby CO2 storage chambers, and open the on-off valve V3 between the selected CO2 storage chamber and the supercritical treatment chamber. The supercritical CO2 in the CO2 storage chamber enters the supercritical treatment chamber through the filter, pressure regulating valve V4, and second mass flowmeter to process the substrate / wafers. After the processing is completed, the supercritical treatment chamber exhausts and relieves pressure, takes out the processed substrate / wafers, and transfers a new substrate to be processed for processing; (4) While performing any one of the processes in step (1) or (2) or (3), complete the conversion of liquid CO2 to the supercritical CO2 state in at least one other CO2 storage chamber according to the operation in step (2), so that the other CO2 storage chambers enter the standby state; (5) During the substrate processing, when the pressure in the operating CO2 storage chamber drops to 10 - 25 MPa, close the on-off valve V3 between the operating CO2 storage chamber and the supercritical treatment chamber, and at the same time open the on-off valve V3 between any standby CO2 storage chamber and the supercritical treatment chamber to achieve the switching between CO2 storage chambers, and use the switched CO2 storage chamber to supply SCC to the supercritical treatment chamber.

8. The method according to claim 7, wherein, The substrate processing process in step (3) is as follows: Supercritical CO2 enters the supercritical treatment chamber, and the supercritical treatment chamber enters the intake pressure boost process, which is called the T1 pressure boost stage. When the pressure inside the supercritical treatment chamber rises to 8 - 18 MPa (preferably 15 - 18 MPa), close the on-off valve V3 and stop supplying SCC. The T1 pressure boost stage ends and enters the T2 static stage. The pressure in the supercritical treatment chamber stabilizes at 8 - 18 MPa and remains for 1 - 60 s. The substrate / wafers are in full contact and replacement with the supercritical CO2. The T2 static stage ends. At the same time, open the on-off valve V3 between the CO2 storage chamber and the supercritical treatment chamber, the pressure regulating valve V4, and the on-off valve V5, pressure regulating valve V6, on-off valve V7, and check valve on the exhaust pipeline to enter the T3 circulation replacement stage. In this stage, the opening degree of the pressure regulating valve V6 is feedback-regulated through the control system so that the pressure in the supercritical treatment chamber always remains at 8 - 18 MPa (preferably 14 - 18 MPa) for 0.5 - 2 min; After the substrate processing is completed, close the on-off valve V3 and the pressure regulating valve V4 between the CO2 storage chamber and the supercritical treatment chamber. The T3 circulation replacement stage ends, and the supercritical treatment chamber enters the T4 exhaust stage. The supercritical treatment chamber is exhausted and relieved of pressure through the exhaust pipeline until the pressure inside the supercritical treatment chamber drops to atmospheric pressure; The T2 static stage may or may not be included in the processing process.

9. The method according to claim 8, wherein, The T3 circulation replacement stage in step (3) can be a steady replacement process with a constant pressure, or a pressure reduction - pressure boost cycle process, or a pressure reduction - static - pressure boost - static cycle process, or a combination of the above processes. Among them, the number of cycles can be 2 - 50 times.

10. The method according to claim 7, wherein This processing method can be used for processing substrates such as drying, cleaning, and washing.

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