Two-fluid nozzle discharge device and spin processing method using the same

Abstract

The present invention provides a two-fluid nozzle discharge device and a spin processing method using the same, which not only allows for the uniform, pulsation-free delivery of liquid at a higher pressure than conventional methods to the liquid inlet side of the two-fluid nozzle, but also prevents pulsation when the mixed fluid is discharged from the two-fluid nozzle. [Solution] A two-fluid nozzle discharge device is provided, comprising: a two-fluid nozzle body; a gas pressurization system equipped with a gas pressurization regulator for supplying pressurized inert gas to the two-fluid nozzle body; a liquid pressurization system equipped with a circulation tank for circulating temperature-controlled liquid and a pump for pressurizing the liquid from the circulation tank in order to supply pressurized liquid to the two-fluid nozzle body; and a liquid booster system equipped with a liquid pressurization regulator that applies further pressure to the liquid being pressurized by supplying pressurized inert gas.

Description

Technical Field

[0001] The present invention relates to a two-fluid nozzle used in a spin processing apparatus for discharging a mixed fluid containing a liquid used in a semiconductor manufacturing process onto a wafer placed on the spin processing apparatus for liquid processing, a spin processing method using the same, and a method for manufacturing a substrate using the same.

Background Art

[0002] In semiconductor manufacturing processes, various semiconductor wafer surface treatments are performed according to each process. Such wafer surface treatments include, in addition to etching for removing a damaged layer after back grinding, application of a developer to the wafer, development of a wafer onto which a developer has been applied after baking a semiconductor circuit on the wafer surface where a circuit pattern has been exposed, cleaning of the wafer surface, and the like.

[0003] As a spin processing apparatus for performing such various wafer surface treatments, the one described in Patent Document 1 is known.

[0004] Such a spin processing apparatus has a dropping nozzle for dropping a chemical solution onto the placed wafer. In Patent Document 1, this dropping nozzle is referred to as an injection pipe.

[0005] Further, in the substrate processing apparatus disclosed in Patent Document 2, a two-fluid nozzle for introducing pure water and nitrogen gas and ejecting droplets of pure water is used, and a semiconductor substrate processing apparatus for cleaning the surface of a rotating wafer is disclosed.

[0006] When a two-fluid nozzle is used in a semiconductor substrate processing apparatus as described above, for example, it is conceivable to apply the two-fluid nozzle discharge apparatus disclosed in Patent Document 3. In particular, if it has a configuration as shown in FIG. 1 of Patent Document 3, it can be applied to a semiconductor spin processing apparatus.

[0007] In semiconductor spin processing equipment, a chemical solution, such as a cleaning solution, is discharged onto a rotating wafer using a two-fluid nozzle. Often, this chemical solution is delivered under pressure, typically using a bellows pump to pressurize it to approximately 0.3 MPa before sending it to the nozzle. Higher pressure and temperature control of the chemical solution improve the substrate cleaning efficiency. The pressure of the gas supplied to the two-fluid nozzle can be controlled using an inert gas regulator.

[0008] Furthermore, while bellows pumps, which are made of fluororesin and other materials, have a longer lifespan than diaphragm pumps, they have a limitation on the pressure they can pressurize liquids to because they will break down if too much pressure is applied. This limits the pressure they can pressurize and prevents the pressure from being increased. Also, using pumps at their maximum capacity significantly shortens the lifespan of diaphragm pumps, bellows pumps, and other types of pumps. Furthermore, a drawback of bellows pumps is that both the discharge and suction sides exhibit pulsation, causing momentary fluctuations in flow rate. This pulsation can lead to uneven cleaning of substrates such as wafers, potentially reducing the overall cleaning efficiency. Consequently, using a bellows pump also results in pulsation when the mixed fluid of chemicals and gases is discharged from the two-fluid nozzle, leading to instability in the substrate processing process. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2001-267278 [Patent Document 2] Japanese Patent Publication No. 2004-349501 [Patent Document 3] WO2022 / 079787A1 [Overview of the project] [Problems that the invention aims to solve]

[0010] The present invention has been made in view of the problems of the prior art described above, and aims to provide a two-fluid nozzle discharge device and a spin processing method using the same, which can not only uniformly pump liquid at a higher pressure than conventional methods without pulsation to the liquid inlet side of the two-fluid nozzle, but also prevent pulsation when the mixed fluid is discharged from the two-fluid nozzle. [Means for solving the problem]

[0011] To solve the above problems, the present invention provides a two-fluid nozzle discharge device for discharging a mixed fluid onto a substrate placed on a spin processing device, while mixing a liquid used in a semiconductor manufacturing process with a gas to form a mixed fluid. The two-fluid nozzle discharge device includes a two-fluid nozzle body, a gas pressurization system equipped with a gas pressurization regulator for supplying pressurized inert gas to the two-fluid nozzle body, a liquid pressurization system equipped with a circulation tank for circulating temperature-controlled liquid and a pump for pressurizing the liquid from the circulation tank to supply pressurized liquid to the two-fluid nozzle body, and a liquid booster system equipped with a liquid pressurization regulator that applies further pressure to the liquid being pressurized by supplying pressurized inert gas.

[0012] It is preferable that the inert gas supplied by the gas pressurizing regulator and the liquid pressurizing regulator is nitrogen gas or argon gas.

[0013] The pump used to pump the liquid from the circulation tank is preferably a bellows pump or a diaphragm pump.

[0014] It is preferable that a filter member for filtering the liquid pumped from the pump is provided downstream of the pump.

[0015] Preferably, the system includes a structure in which, while the mixed fluid is not being discharged from the two-fluid nozzle body, the valve of the liquid booster system is closed, and the supply of the pressurized inert gas to the pressurized liquid is stopped.

[0016] The spin processing method of the present invention is a spin processing method for performing spin processing on a substrate placed on a spin processing apparatus using the two-fluid nozzle discharge apparatus.

[0017] The method for manufacturing a processed substrate of the present invention is a method for manufacturing a processed substrate including a processing step by the spin processing method.

Advantages of the Invention

[0018] According to the present invention, not only can the liquid be uniformly pumped at a higher pressure than conventional without pulsation to the liquid inlet side of the two-fluid nozzle, but also the pulsation when the mixed fluid is discharged from the two-fluid nozzle can be prevented. Thus, a two-fluid nozzle discharge apparatus and a spin processing method using the same can be provided, achieving a remarkable effect.

[0019] Also, according to the present invention, since excessive pressure is not applied to the pump, the load is small, the life of the pump is longer than conventional, and the failures are very few.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic configuration diagram showing an embodiment in which the two-fluid nozzle discharge apparatus of the present invention is applied to a spin processing apparatus. [Figure 2] It is a schematic diagram of a main part showing one embodiment of the two-fluid nozzle. [Figure 3] It is a schematic configuration diagram showing an embodiment in which the two-fluid nozzle discharge apparatus of Comparative Example 1 is applied to a spin processing apparatus.

Embodiments for Carrying Out the Invention

[0021] Embodiments of the present invention will be described below. These embodiments are shown by way of example, and it is needless to say that various modifications are possible without departing from the technical idea of the present invention. In the drawings, the same members are denoted by the same reference numerals.

[0022] In Figure 1, reference numeral 10 indicates one embodiment of the two-fluid nozzle dispensing device of the present invention. The two-fluid nozzle dispensing device 10 is a two-fluid nozzle dispensing device for dispensing a mixed fluid onto a substrate W placed on a spin processing device 12, while mixing a liquid used in the semiconductor manufacturing process with a gas to form a mixed fluid.

[0023] The spin processing apparatus 12 includes any spin processing apparatus used in the semiconductor manufacturing process. For example, the spin processing apparatus described in Patent Document 1 can be applied. In particular, a spin processing apparatus that performs cleaning is preferred. Therefore, the liquid used in the semiconductor manufacturing process is a processing liquid for performing some kind of treatment on the surface of the substrate W.

[0024] The processing solution includes various types of processing solutions, such as chemical solutions, cleaning solutions, and rinsing solutions. In the case of a spin processing device that performs cleaning, the liquids used as processing solutions include cleaning solutions used for cleaning and rinsing solutions used for rinsing. Cleaning solutions are sometimes called cleaning chemical solutions, and sometimes cleaning solutions are simply referred to as chemical solutions.

[0025] Reference numeral 14 denotes a liquid recovery mechanism for recovering the liquid discharged onto the surface of the substrate W. As such a liquid recovery mechanism 14, for example, a waste liquid recovery mechanism equipped with an annular waste liquid recovery trough described in Patent Document 1 can be applied.

[0026] Suitable substrates for the substrate W include silicon substrates, as well as compound semiconductor substrates such as SiC (silicon carbide), GaN (gallium nitride), or SiN (silicon nitride film). Furthermore, wafer-shaped semiconductor substrates are preferred for the substrate W.

[0027] The two-fluid nozzle discharge device 10 includes a two-fluid nozzle body 16, a gas pressurization system 20 equipped with a gas pressurization regulator 18 for supplying pressurized inert gas to the two-fluid nozzle body 16, a liquid pressurization system 26 equipped with a circulation tank 22 for circulating temperature-controlled liquid to supply pressurized liquid to the two-fluid nozzle body 16, and a pump 24 for pressurizing the liquid from the circulation tank 22, and a liquid booster system 30 equipped with a liquid pressurization regulator 28 for adding further pressure to the liquid being pressurized by supplying pressurized inert gas.

[0028] The gas pressurizing regulator 18 is designed to pressurize an inert gas to 0.3 MPa, and is capable of pressurizing up to a maximum of 0.4 MPa. The liquid pressurization regulator 28 is designed to pressurize a liquid to 0.3 MPa, and is capable of pressurizing up to a maximum of 0.4 MPa.

[0029] In the context of the gas pumping system 20, liquid pumping system 26, and liquid booster system 30, "system" means "system" and is synonymous with gas pumping system, liquid pumping system, and liquid booster system, respectively.

[0030] As shown in Figure 2, any two-fluid nozzle body 16 equipped with a gas inlet 32 ​​and a liquid inlet 34, which mixes the gas and liquid and discharges the mixed fluid 38 from the nozzle tip 36, is applicable. There are no special limitations on the amount of mixed fluid sprayed from the two-fluid nozzle body 16 or the spray pattern, and these can be adjusted as appropriate. Furthermore, there are no special limitations on the method of mixing the gas and liquid in the two-fluid nozzle body, such as internal mixing type, external mixing type, or impact type, and all are applicable.

[0031] Nitrogen gas or argon gas is preferably used as the inert gas supplied by the gas pressurizing regulator 18 and the liquid pressurizing regulator 28.

[0032] In Figure 1, the two-fluid nozzle discharge device 10 is provided with piping 40, 42, 44, 45, and 47 in the paths that include the gas pumping system 20, the liquid pumping system 26, and the liquid booster system 30, respectively. In addition, piping 48 is provided in the liquid recovery system 46 for returning the liquid from the liquid recovery mechanism 14 back to the circulation tank 22.

[0033] The liquid recovery system 46 is also equipped with a pump 50. The piping, including pipes 40, 42, 44, 48, 45, and 47, is preferably constructed from fluororesin tubes such as PFA tubing. This is because using chemically resistant fluororesin materials with low impurity levels prevents contamination by foreign substances.

[0034] Furthermore, a bellows pump or a diaphragm pump is preferably used as the pump 24 that pumps the liquid from the circulation tank 22 and the pump 50 that returns the liquid to the circulation tank 22. Although diaphragm pumps can increase pressure due to their structure, they have the disadvantage of a shorter lifespan due to their fast operation. However, in the case of the two-fluid nozzle discharge device 10 of the present invention, the pump 24 that pumps the liquid from the circulation tank 22 is subjected to a pressure of 0.2 MPa or less, so either a bellows pump or a diaphragm pump can be used. In addition, there is the advantage that the lifespan of the pump 24 is longer and there are fewer malfunctions. In the illustrated example, an example of a bellows pump is shown. This is because a long-life bellows pump can be selected if the pump is only for circulation and the normal pressure is 0.2 MPa or less. When using a diaphragm pump, the configuration can be basically the same as the embodiment shown in Figure 1 by simply replacing the bellows pump.

[0035] Furthermore, in Figure 1, reference numeral 52 denotes a heater for warming the circulating liquid. The heater 52 has the function of warming the circulating liquid to a maximum of 80°C. Furthermore, reference numeral 54 denotes a filter member provided in the piping 45. Thus, downstream of the pump 24, a filter member is provided to filter the liquid pumped from the pump 24. Here, downstream means downstream of the liquid flow. The filter member 54 cannot be attached if the liquid flowing through the piping 45 is at high pressure, but in the present invention, the liquid flowing through the piping 45 can be circulated at 0.2 MPa or less, so this configuration with the filter member 54 can be provided.

[0036] Each of the pathways, including the gas pumping system 20, the liquid pumping system 26, and the liquid booster system 30, is equipped with multiple valves, namely the first valve 56, the second valve 58, the third valve 60, the fourth valve 62, the fifth valve 64, and the sixth valve 66.

[0037] Furthermore, in Figure 1, reference numeral 68 denotes a pressure tank. Costs can be reduced by using a thick pipe (for example, a pipe with a diameter of 1 inch) as the pressure tank 68. A fluororesin tube such as a PFA tube is also preferable for the pressure tank 68, and a thick pipe with a diameter of 1 inch or more is preferably used. This pressure tank 68 preferably has a capacity of approximately 1 L, but the capacity can be changed by changing the length of the pressure tank 68.

[0038] Furthermore, the pressure tank 68 is equipped with an empty sensor 70 and a full sensor 72 for detecting the amount of liquid inside. For example, known liquid level sensors can be used for the empty sensor 70 and the full sensor 72. The present invention is characterized in that the supply of liquid to the two-fluid nozzle body 16 is separated from the circulation of liquid by the circulation tank by using the pressure tank 68. As a result, the pressure of the liquid being pumped from the pressure tank 68 and the pressure of the gas being pumped from the liquid pressurizing regulator 28 can be increased to a maximum of 0.5 MPa according to the specifications.

[0039] Thus, the present invention was devised to meet the demand for supplying a high-temperature liquid at high pressure to the liquid inlet side of a two-fluid nozzle body.

[0040] Furthermore, while the mixed fluid 38 is not being discharged from the two-fluid nozzle body 16, at least the fifth valve 64, which is a valve of the liquid booster system 30, is closed, and the supply of the pressurized inert gas to the liquid being pumped is stopped.

[0041] The spin treatment method of the present invention is a spin treatment method that uses a two-fluid nozzle discharge device 10 to perform spin treatment on a substrate W placed on a spin treatment device 12. Spin treatment includes any treatment that performs spin treatment on the substrate W using the spin treatment device 12, such as cleaning treatment, rinsing treatment, and chemical treatment. Cleaning solutions are sometimes called cleaning chemicals, and cleaning treatment may be included in chemical treatment.

[0042] Furthermore, the manufacturing method for the treated substrate of the present invention is a manufacturing method that includes a processing step of performing spin processing on the substrate surface using the spin processing method of the present invention. In this way, a substrate with a treated surface is manufactured by spin processing.

[0043] Next, an efficient control method for the two-fluid nozzle discharge device 10 is shown. When the mixed fluid 38 is not being discharged from the two-fluid nozzle body 16, the liquid is circulated from the circulation tank to warm the unused liquid to an appropriate temperature. The valve state at this time is shown in Table 1.

[0044] [Table 1]

[0045] When the mixed fluid is not being discharged, the temperature-controlled liquid sent from the circulation tank 22 passes through the pressure-resistant tank 68 and returns to the circulation tank 22. The empty detection sensor 70 and the full detection sensor 72 are kept in the ON state. Since the liquid is circulated at a pressure of 0.2 MPa or less in this route, there is no need to worry about the pump 24 breaking down. Currently, there are no pumps on the market that can withstand pressures of 0.4 MPa or higher for installation in piping with the above configuration. In this invention, since the liquid sent from the circulation tank 22 is pumped at a pressure below the pressure resistance of the pump through which it passes, the pump has the advantage of having a very long lifespan and being less prone to failure. In addition, the pressure-resistant tank 68, in the illustrated example, uses 1-inch piping and has a pressure resistance of 0.7 MPa. The first valve 56 to the sixth valve 66 have a pressure resistance of 0.7 MPa.

[0046] Table 2 shows the valve state when the mixed fluid 38 is discharged from the two-fluid nozzle body 16.

[0047] [Table 2]

[0048] During discharge, discharge for about 60 seconds, and once the liquid in the pressure tank 68 is empty, return to the original circulation. Then, after about 60 seconds, discharge again. Repeat this process.

[0049] In this way, the pump 24 through which the liquid sent from the circulation tank 22 passes is not subjected to any pressure load. Consequently, the lifespan of the pump 24 is extended, and the frequency of failures is drastically reduced. Furthermore, pulsation can also be suppressed. In addition, the pipes 44, 45, 47, 48, etc. through which the liquid passes are wrapped with insulating material to enhance heat retention, resulting in a two-fluid discharge system. [Examples]

[0050] The present invention will be described in more detail below with reference to examples, but it goes without saying that these examples are provided illustratively and should not be interpreted as limiting.

[0051] (Example 1) <Device configuration> Using the two-fluid nozzle discharge device shown in Figure 1, spin processing was performed using a spin processing device under the following conditions. <Conditions for Example 1> Substrate: Silicon wafer Two-fluid nozzle body: Two-fluid nozzle (made of fluororesin) manufactured by Ikeuchi Co., Ltd. Liquid: Organic solvents are used as cleaning agents. Gas: Nitrogen Pump through which the liquid pumped from the circulation tank passes: Commercially available bellows pump Temperature for adjusting the temperature of the circulating liquid: Approximately 60°C Liquid pressure: Approximately 0.28 MPa Gas pressure: Approximately 0.28 MPa Liquid flow rate: approx. 0.3L / min Gas flow rate: Approximately 20 NL / min Usage: 5 million cycles / month

[0052] Results: Even after 3 months (approximately 15 million uses), the pump through which the liquid pumped from the circulation tank passes did not malfunction. This was because the discharge pressure could be set to the two-fluid nozzle body using only gas pressure without putting any strain on the pump. Furthermore, the liquid could be pumped uniformly and without pulsation to the liquid inlet side of the two-fluid nozzle body. In addition, pulsation when the mixed fluid was discharged from the two-fluid nozzle body was prevented. As a result, no cleaning streaks occurred on the substrate.

[0053] (Comparative Example 1) <Device configuration> Figure 3 shows an example configuration in which a two-fluid nozzle dispensing device 100 is used to perform spin processing on the surface of a substrate W placed on a spin processing device 12. The two-fluid nozzle dispensing device 100 includes a two-fluid nozzle body 102, a gas pressurization system 110 equipped with a gas pressurization regulator 106 for supplying pressurized inert gas to the two-fluid nozzle body 102, a liquid pressurization system 133 equipped with a circulation tank 118 for circulating temperature-controlled liquid to supply pressurized liquid to the two-fluid nozzle body 16, a pump 132 for pressurizing the liquid from the circulation tank 118, and a liquid recovery system 112 for returning liquid from the liquid recovery mechanism 14 to the circulation tank 118. The two-fluid nozzle body 102 has the same configuration as the two-fluid nozzle body 16 described above.

[0054] In Figure 3, reference numeral 108 denotes a valve and reference numeral 104 denotes piping. The liquid in the circulation tank 118 is heated to an appropriate temperature (liquid temperature 60°C) by the heater 122 and filtered by the filter member 120. Reference numeral 124 denotes a pump (bellows pump in the illustrated example) and reference numeral 126 denotes piping.

[0055] In Figure 3, the liquid recovery system 112, which returns the liquid from the liquid recovery mechanism 14 to the circulation tank 118, is equipped with a pump 116, which returns the liquid to the circulation tank 118 through piping 114. The liquid from the circulation tank 118 is then pumped at 0.28 MPa to the two-fluid nozzle body 102 through a diaphragm pump 132. Reference numeral 130 denotes piping, and reference numeral 136 denotes a valve.

[0056] Furthermore, in Figure 3, piping 128 and valve 134 are provided so that the liquid from the circulation tank 118 returns to the circulation tank 118 when valve 136 is closed. In the configuration of Figure 3, there is no pressure tank 68, nor is there a liquid booster system 30.

[0057] The gas pressurizing regulator 106 is designed to pressurize an inert gas to 0.3 MPa. <Conditions for Comparative Example 1> Substrate: Silicon wafer Two-fluid nozzle body: Two-fluid nozzle (made of fluororesin) manufactured by Ikeuchi Co., Ltd. Liquid: Organic solvents are used as cleaning agents. Gas: Nitrogen Pump through which the liquid pumped from the circulation tank passes: a commercially available diaphragm pump. Temperature for adjusting the temperature of the circulating liquid: Approximately 60°C Liquid pressure: Approximately 0.28 MPa Gas pressure: Approximately 0.28 MPa Liquid flow rate: approx. 0.3L / min Gas flow rate: Approximately 20 NL / min Usage: 5 million cycles / month

[0058] Results: Repeated pumping of liquid caused the pump (diaphragm pump 132) through which the liquid pumped from the circulation tank passed to fail after one month (approximately 5 million uses). This was roughly the same number of uses as indicated in the pump's catalog lifespan. Furthermore, it was not possible to pump the liquid uniformly without pulsation to the liquid inlet side of the two-fluid nozzle, and pulsation sometimes occurred. Pulsation also sometimes occurred when the mixed fluid was discharged from the two-fluid nozzle. As a result, some substrates developed uneven cleaning. [Explanation of Symbols]

[0059] 10: Two-fluid nozzle discharge device of the present invention, 12: Spin processing device, 14: Liquid recovery mechanism, 16, 102: Two-fluid nozzle body, 18, 106: Gas pressurizing regulator, 20, 110: Gas pressurizing system, 22, 118: Circulation tank, 24, 50, 116, 124, 132: Pump, 26, 112, 133: Liquid pressurizing system, 28: Liquid pressurizing regulator, 30: Liquid booster system, 32: Gas inlet, 34: Liquid inlet, 36: Nozzle Lutip, 38: mixed fluid, 40, 42, 44, 45, 47, 48, 104, 114, 128: piping, 46: liquid recovery system, 52, 122: heater, 54, 120: filter component, 56: first valve, 58: second valve, 60: third valve, 62: fourth valve, 64: fifth valve, 66: sixth valve, 68: pressure tank, 70: empty detection sensor, 72: full detection sensor, 100: two-fluid nozzle discharge device of Comparative Example 1, 134, 136: valve, W: substrate.

Claims

1. This is a two-fluid nozzle dispensing device for dispensing a mixed fluid onto a substrate placed on a spin processing device, while mixing a liquid used in the semiconductor manufacturing process with a gas to form a mixed fluid. The two-fluid nozzle body, A gas pressurization system comprising a gas pressurizing regulator for supplying pressurized inert gas to the two-fluid nozzle body, A liquid pumping system comprising a circulation tank for circulating temperature-controlled liquid and a pump for pumping liquid from the circulation tank, for supplying pressurized liquid to the two-fluid nozzle body, A liquid booster system comprising a liquid pressurizing regulator that applies further pressure to the liquid being pumped by supplying pressurized inert gas, including, Two-fluid nozzle dispensing device.

2. The two-fluid nozzle discharge device according to claim 1, wherein the inert gas supplied by the gas pressurizing regulator and the liquid pressurizing regulator is nitrogen gas or argon gas.

3. The two-fluid nozzle discharge device according to claim 1, wherein the pump for pumping the liquid from the circulation tank is a bellows pump or a diaphragm pump.

4. The two-fluid nozzle discharge device according to claim 1, wherein a filter member for filtering the liquid pumped from the pump is provided downstream of the pump.

5. The two-fluid nozzle discharge device according to claim 1, further comprising a structure in which, while the mixed fluid is not being discharged from the two-fluid nozzle body, the valve of the liquid booster system is closed, thereby stopping the supply of the pressurized inert gas to the pressurized liquid.

6. A spin processing method comprising performing spin processing on a substrate placed on a spin processing device using a two-fluid nozzle discharge device according to any one of claims 1 to 5.

7. A method for manufacturing a processed substrate, comprising a processing step by the spin processing method described in claim 6.

Images