Substrate processing method and substrate processing apparatus

Abstract

This invention provides a substrate processing method and a substrate processing apparatus. The substrate processing method includes: a cleaning liquid film formation step, wherein a cleaning liquid is supplied to the substrate while rotating the substrate to form a liquid film of cleaning liquid on the surface of the substrate; a first chemical solution treatment step, wherein a chemical solution is supplied to the substrate at a first supply flow rate while rotating the substrate at a first rotational speed to form a liquid film of chemical solution of a first thickness on the surface of the substrate, and the substrate is treated with the chemical solution; and a second chemical solution treatment step, wherein a chemical solution identical to the chemical solution used in the first liquid film treatment step is supplied to the substrate at a second supply flow rate while rotating the substrate at a second rotational speed to form a liquid film of chemical solution of a second thickness on the surface of the substrate, and the substrate is treated with the chemical solution, wherein the cleaning liquid is a liquid different from the chemical solution used in the first and second chemical solution treatment steps and has a higher cleanliness than the chemical solution used in those steps, the first supply flow rate is greater than the second supply flow rate, and the first thickness is greater than the second thickness.

Description

Technical Field

[0001] This invention relates to a substrate processing method and a substrate processing apparatus. Background Technology

[0002] Semiconductor device manufacturing processes include a liquid treatment process, in which a treatment liquid, such as an etching or cleaning solution, is supplied to a substrate to perform a prescribed liquid treatment on the substrate. To reduce the number of particles remaining on the substrate after liquid treatment, it is necessary to reduce the number of particles contained in the treatment liquid supplied to the substrate. Patent Document 1 discloses a substrate processing apparatus in which the particles in the treatment liquid include particles generated from a control valve used to regulate the flow rate of the treatment liquid supplied to the liquid treatment unit, and this substrate processing apparatus includes a unit for reducing such particles.

[0003] Patent Document 1 discloses a substrate processing apparatus comprising: a first pipeline connected to a processing liquid supply source; a pump for supplying processing liquid from the processing liquid supply source to the first pipeline; a plurality of second pipelines connected to the first pipeline, wherein processing liquid flowing through the first pipeline flows into the plurality of second pipelines; branch pipelines connected to branch points on each of the second pipelines; a liquid processing unit for processing the substrate using processing liquid supplied via each branch pipeline; a throttling orifice disposed in each of the second pipelines at a position upstream of the branch point; and a first control valve disposed in each of the second pipelines at a position downstream of the branch point. The first control valve controls the pressure of the processing liquid in the interval between the throttling orifice of the corresponding second pipeline and the first control valve by changing the amount of processing liquid flowing in the position downstream of the first control valve, thereby controlling the flow rate of the processing liquid supplied to the corresponding liquid processing unit via the corresponding branch pipeline. According to the above structure, it is unnecessary to provide a control valve for adjusting the flow rate in the branch pipelines, therefore particles generated from such a control valve will not flow to the liquid processing unit.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-041751 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] This disclosure provides a technique that can reduce the consumption of pharmaceutical solutions and reduce the amount of particulate matter remaining on the substrate after liquid treatment.

[0009] Solution for solving the problem

[0010] One embodiment of the substrate processing method includes: a cleaning liquid film formation step, wherein a cleaning liquid is supplied to the substrate while rotating the substrate to form a liquid film of the cleaning liquid on the surface of the substrate; a first chemical solution treatment step, wherein, after the cleaning liquid film formation step, a chemical solution is supplied to the substrate while rotating the substrate at a first rotational speed at a first supply flow rate to form a chemical solution liquid film of a first thickness on the surface of the substrate, and the substrate is treated using the chemical solution; and a second chemical solution treatment step, wherein, after the first chemical solution treatment step, a chemical solution identical to the chemical solution used in the first chemical solution treatment step is supplied to the substrate while rotating the substrate at a second rotational speed at a second supply flow rate to form a chemical solution liquid film of a second thickness on the surface of the substrate, and the substrate is treated using the chemical solution, wherein the cleaning liquid is a different liquid from the chemical solution used in the first chemical solution treatment step and the second chemical solution treatment step, the cleaning liquid has a higher cleanliness than the chemical solution, the first supply flow rate is greater than the second supply flow rate, and the first thickness is greater than the second thickness.

[0011] The effects of the invention

[0012] According to this disclosure, the consumption of the liquid solution can be reduced and the amount of particles remaining on the substrate after liquid treatment can be reduced. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view that schematically illustrates the structure of a substrate processing system according to one embodiment of the substrate processing apparatus.

[0014] Figure 2 It is a summary view Figure 1 The diagram shows the piping system of the processing liquid supply mechanism of the substrate processing apparatus.

[0015] Figure 3 It is a summary of the relationship with Figure 2 The diagram shows the piping system of the processing fluid supply mechanism associated with a processing unit.

[0016] Figure 4 This is a timing diagram showing the rotational speed of the substrate and the ejection flow rate of the processing liquid in each step of the liquid treatment process in one embodiment.

[0017] Figure 5 It is a schematic diagram used to illustrate the spraying status of the treatment liquid in each process of liquid treatment.

[0018] Figure 6 It is a schematic diagram used to illustrate the initial state of the initial thick film formation process.

[0019] Figure 7It is a schematic diagram used to illustrate the final state of the initial thick film formation process.

[0020] Figure 8 This is a schematic diagram showing the flow rate distribution of the drug solution in the liquid film. Detailed Implementation

[0021] An embodiment of the substrate processing apparatus will be described with reference to the accompanying drawings.

[0022] Figure 1 This is a diagram showing the outline structure of the substrate processing system according to this embodiment. Hereinafter, to clarify the positional relationships, the mutually orthogonal X-axis, Y-axis, and Z-axis are defined, with the positive direction of the Z-axis set as the vertically upward direction.

[0023] like Figure 1 As shown, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are arranged adjacent to each other.

[0024] The loading / unloading station 2 includes a carrier placement section 11 and a transport section 12. The carrier placement section 11 holds multiple carriers C that horizontally accommodate multiple substrates, which in this embodiment are semiconductor wafers or other substrates W.

[0025] The conveying section 12 is disposed adjacent to the carrier placement section 11, and the conveying section 12 includes a substrate conveying device 13 and a transfer section 14. The substrate conveying device 13 includes a substrate holding mechanism for holding the substrate W. In addition, the substrate conveying device 13 can move in the horizontal and vertical directions and rotate about the vertical axis. The substrate conveying device 13 uses the substrate holding mechanism to convey the substrate W between the carrier C and the transfer section 14.

[0026] Processing station 3 is arranged adjacent to conveying section 12. Processing station 3 includes conveying section 15 and multiple processing units 16. Multiple processing units 16 are arranged on both sides of conveying section 15.

[0027] The transfer unit 15 is equipped with a substrate transfer device 17. The substrate transfer device 17 is equipped with a substrate holding mechanism for holding the substrate W. In addition, the substrate transfer device 17 can move in the horizontal and vertical directions and rotate about the vertical axis. The substrate transfer device 17 uses the substrate holding mechanism to transfer the substrate W between the transfer unit 14 and the processing unit 16.

[0028] The processing unit 16 performs a prescribed substrate processing on the substrate W transported by the substrate transport device 17.

[0029] Furthermore, the substrate processing system 1 includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various processes performed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing the programs stored in the storage unit 19.

[0030] Alternatively, the above-mentioned program may be recorded in a computer-readable storage medium and installed from that storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include hard disks (HD), floppy disks (FD), optical disks (CD), magneto-optical disks (MO), and memory cards.

[0031] In the substrate processing system 1 configured as described above, firstly, the substrate transport device 13 of the transport station 2 removes the substrate W from the carrier C placed in the carrier placement section 11 and places the removed substrate W in the transfer section 14. The substrate W placed in the transfer section 14 is then removed from the transfer section 14 by the substrate transport device 17 of the processing station 3 and transported into the processing unit 16.

[0032] After the substrate W is processed by the processing unit 16, the substrate W is removed from the processing unit 16 by the substrate transfer device 17 and placed in the transfer section 14. Then, the processed substrate W placed in the transfer section 14 is returned to the carrier C of the carrier placement section 11 by the substrate transfer device 13.

[0033] Next, refer to Figure 2 and Figure 3 This describes a processing fluid supply system that supplies processing fluid to multiple processing units 16. The processing fluid supply system includes a chemical supply system. Figure 2 The diagram shows the piping system for the drug supply system.

[0034] The medicine supply system 30 includes a tank 32 for storing the medicine and a circulation line 34 for allowing the medicine to flow out of and back into the tank 32. A pump 36 is installed in the circulation line 34. The pump 36 creates a circulating flow that exits from the tank 32 and returns to the tank 32 via the circulation line 34. A filter 38 and a temperature regulator 40 are installed in the circulation line 34. The filter 38 removes contaminants such as particles from the medicine, and the temperature regulator 40 adjusts the temperature of the medicine to a predetermined temperature. When supplying the medicine to the substrate W at room temperature, the temperature regulator 40 can be a type that utilizes a Peltier element for cooling / heating.

[0035] Multiple branch lines (also referred to as "distribution lines") 44 are connected in parallel in the connection area 42 of the circulation line 34. Each branch line 44 is used to supply the liquid medicine flowing in the circulation line 34 to the corresponding processing unit 16. In order to stabilize the pressure in the connection area 42 of the circulation line 34, a pressure regulating valve 43 is provided on the downstream side of the connection area 42.

[0036] The medicine supply system 30 also includes a tank replenishment section 46 for replenishing medicine or components thereof to the tank 32. A drain section 48 is provided in the tank 32 for discharging medicine from the waste tank 32.

[0037] like Figure 3 As shown, in a branch line 44, a flow meter 50, a pressure regulating valve 52 (serving as a flow control valve), and an on / off valve 54 are sequentially installed from the upstream side. A liquid nozzle 56 is installed at the downstream end of the branch line 44. Between the on / off valve 54 and the liquid nozzle 56, a drain line 58 branches off from the branch line 44. An on / off valve 60 is installed in the drain line 58.

[0038] Flow meter 50 and pressure regulating valve 52 constitute a flow regulating unit for adjusting the flow rate of the liquid medicine flowing in branch line 44. Pressure regulating valve 52 operates to achieve a secondary side pressure corresponding to the operating pressure (air pressure) supplied to the pilot orifice of pressure regulating valve 52 by an electro-pneumatic regulator (not shown). This is achieved via a control device ( Figure 1 The control device 4 or its lower-level controller provides feedback control to the operating pressure supplied to the pilot orifice of the pressure regulating valve 52 so that the detected flow rate of the flow meter 50 becomes the desired value (set value).

[0039] The liquid nozzle 56 is carried by Figure 3 The front end of nozzle arm 62 is shown in a schematic diagram. A flushing nozzle 64 and an IPA nozzle 66 are also supported at the front end of nozzle arm 62. At least one of the flushing nozzle 64 and IPA nozzle 66 may also be supported by a nozzle arm other than nozzle arm 62 (not shown).

[0040] The flushing fluid (e.g., DIW) can be supplied to the flushing nozzle 64 from the flushing fluid supply source 65A via the flushing fluid line 65C, which is equipped with a flushing fluid supply control unit 65B, at a controlled flow rate. The flushing fluid supply control unit 65B includes an on / off valve, a flow control valve, etc. (not shown), to control the switching of flushing fluid supply / supply stop and the flushing fluid supply flow rate.

[0041] IPA (isopropyl alcohol) can be supplied to IPA nozzle 66 from IPA supply source 67A via IPA pipeline 67C equipped with IPA supply control unit 67B at a controlled flow rate. IPA supply control unit 67B is equipped with on / off valve, flow control valve, etc. (not shown) to control the switching of IPA supply / supply stop and the supply flow rate of IPA.

[0042] The processing unit 16 has a rotary clamp (substrate holding and rotating mechanism) 70. The rotary clamp 70 has: a substrate holding part (clamping part) 72, which holds the substrate W in a horizontal position; and a rotation drive part 74, which rotates the substrate holding part 72 and the substrate W held thereon about a vertical axis.

[0043] The substrate holding part 72 can be a type of holding part called a mechanical chuck that mechanically holds the periphery of the substrate W using holding members such as grippers, or a type of holding part called a vacuum suction cup that vacuum-adsorbs the center of the back side of the substrate W. The rotation drive part 74 can be, for example, an electric motor.

[0044] A liquid receiving cup 76 is provided around the substrate holding section to collect the processing liquid that splashes out from the rotating substrate W. The processing liquid collected by the liquid receiving cup 76 is discharged to the outside of the processing unit 16 through a drain port 78 provided at the bottom of the liquid receiving cup 76. An exhaust port 80 is also provided at the bottom of the liquid receiving cup 76, through which the interior of the liquid receiving cup 76 is drawn in.

[0045] The nozzle arm 62 allows the liquid nozzle 56, rinsing nozzle 64, and IPA nozzle 66 to be moved between a position directly above the center of the substrate W held by the rotating clamp 70 (processing position) and a position outside the liquid receiving cup 76 (outer radial direction) (retracted position). A pseudo-dispensing port 82 is provided below the liquid nozzle 56, rinsing nozzle 64, and IPA nozzle 66 to receive liquid ejected from the nozzles 56, 64, and 66 in the retracted position.

[0046] Next, refer to Figure 4 Timing diagram and Figure 5 The schematic diagram illustrates a series of liquid processing steps performed on the substrate W in the processing unit 16. As an example, the substrate W is a semiconductor wafer, and the liquid processing is a chemical treatment performed during the BEOL (wired interconnect) process. The chemical solutions used in this treatment can be organic solutions such as BHF (buffered hydrofluoric acid), DHF (diluted hydrofluoric acid), and NH4F (ammonium fluoride). All processing solutions (pre-wetting solution, chemical solution, etc.) used in the following liquid processing are at room temperature. Furthermore, the types of liquid processing, the chemical solutions used, and the temperatures of the processing solutions described above are merely examples and are not limited to those described herein.

[0047] exist Figure 4 In the timing diagram, the upper half shows the rotation speed of the substrate W, and the lower half shows the spray flow rate of the processing liquid (dashed lines represent the liquid, solid lines represent the pre-wetting liquid and rinsing liquid, and dotted lines represent IPA).

[0048] Furthermore, it should be noted that the challenge in this embodiment is not only to prevent or suppress the adhesion of particles of the size that were previously required to be reduced to the substrate W, but also to prevent or suppress the adhesion of particles smaller than that size (hereinafter referred to as "micro-size" in this specification) (e.g., particles of about 13 nm in size) to the substrate W. For example, when the valve body leaves the valve seat in the on / off valve (54), or when the valve body falls into the valve seat, dust is generated due to the interference (e.g., friction) between the valve body and the valve seat, and such micro-size particles are generated as a result. In other valves with movable parts provided in the branch line 44 (e.g., flow control valve (52)), dust may theoretically be generated as well, but the possibility of dust generation in the flow control valve (52) used in the process liquid supply system of the semiconductor manufacturing apparatus is much lower than that in the on / off valve (54), so the flow control valve (52) is not considered in this specification.

[0049] [Drug Dispensing Process (Step S1)]

[0050] The substrate W is moved into the processing unit 16 and held in place by the rotating clamp 70. When the substrate W is moved into the processing unit 16, the liquid nozzle 56 is in the retracted position, directly above the pseudo-dispensing port 82. From this position, firstly, the on / off valve 54 is opened to perform pseudo-dispensing (refer to...) where liquid is sprayed from the liquid nozzle 56 toward the pseudo-dispensing port 82 for a predetermined time. Figure 5 (a)

[0051] The pseudo-dispensing is performed at least until all the liquid retained in the section of branch line 44 from the on / off valve 54 to the liquid nozzle 56 is ejected from the liquid nozzle 56. Specifically, for example, the flow rate of the liquid ejected from the liquid nozzle 56 is set to 200 mL / min, and the pseudo-dispensing is performed for 30 seconds. Alternatively, the flow rate of the liquid can be increased to shorten the dispensing time.

[0052] Alternatively, the pseudo-dispensing may be performed until all the liquid that was retained in the entire area of ​​the branch line 44 (that is, the area from the connection point with the circulation line 34 to the liquid nozzle 56) is sprayed out from the liquid nozzle 56.

[0053] By performing a sham dispensing, contaminants such as particles that remain in the flow path inside the liquid nozzle 56 and branch line 44 or adhere to the liquid contact surface can be discharged. Furthermore, by spraying out at least all the liquid remaining in the branch line 44 from the on / off valve 54 to the liquid nozzle 56 through the liquid nozzle 56 during sham dispensing, it is possible to prevent temporary residue of dust (particles) generated by the on / off valve 54 in the liquid within the branch line 44 immediately after sham dispensing stops. Additionally, by performing sham dispensing, even if the inside of the liquid nozzle 56 is contaminated due to the surrounding environment, such contaminants can be discharged.

[0054] If the liquid nozzle 56 and the rinsing nozzle 64 are mounted on different nozzle arms, at least a portion of the period for performing the liquid pseudo-dispensing process may overlap with the period for performing the pre-wetting process, as described later.

[0055] [Pre-wetting process (step S2)]

[0056] After the pseudo-dispensing process of the drug solution is completed, the rinsing nozzle 64 is positioned directly above the center of the substrate W, and the substrate W is rotated at a low speed (e.g., 100 rpm to 150 rpm). In this state, a cleaning liquid, which serves as a pre-wetting solution, is sprayed from the rinsing nozzle 64 at a high flow rate (e.g., 1500 mL / min), in this case, DIW (pure water) (see reference). Figure 5 (b)). The pre-wetting process is performed for, for example, 5 seconds. The pre-wetting liquid that falls onto the center of the substrate W flows while spreading towards the periphery of the substrate W by centrifugal force, thereby covering the entire surface of the substrate W with a liquid film of the pre-wetting liquid.

[0057] In addition, during the initial stage of spraying the pre-wetting liquid, the pre-wetting liquid may contain dust generated by the opening and closing of the valve, as described later. However, due to the large flow rate of the pre-wetting liquid, the dust (particulate matter) hardly adheres to the surface of the substrate W.

[0058] As long as a relatively thick pre-wetting liquid (DIW) film (that is, a liquid film that is not easily lost due to shaking) is uniformly formed on the entire surface of the substrate W, the rotation speed of the substrate W and the spray flow rate of the pre-wetting liquid in the pre-wetting process are not limited to those described above. As an example, if the surface of the substrate W has both hydrophobic and hydrophilic surfaces, from the viewpoint of liquid film uniformity, it is preferable to set the rotation speed of the substrate to be high. In this case, the spray flow rate of the pre-wetting liquid can also be increased to form a thicker liquid film.

[0059] To confirm the effectiveness of the pre-humidification process, actual trials were conducted under the conditions described in this specification (with the pre-humidification process) and under conditions different only from those conditions, without the pre-humidification process. As a result, the number of particles in the case with the pre-humidification process was approximately 50% of the number of particles in the case without the pre-humidification process.

[0060] Furthermore, we attempted to process the substrate under the conditions described in this specification while varying the rotation speed of the substrate during the pre-wetting process (with the ejection flow rate fixed at 1500 mL / min). As a result, we confirmed a tendency for lower rotation speeds (i.e., larger film thicknesses) to result in fewer particles.

[0061] Dilute ammonia can also be used as the pre-wetting solution. Additionally, dilute ammonia can also be used as the rinsing solution in the rinsing process described later. Generally, it is known that the zeta potential of solid surfaces (both the substrate surface and the particle surface) is negative in alkaline liquids, making it difficult for particles to adhere. In this embodiment, where suppressing particle adhesion is required, it is advantageous to use dilute ammonia as at least one of the pre-wetting solution and the rinsing solution. In fact, when dilute ammonia is used as both the pre-wetting solution and the rinsing solution, a further reduction in particles can be observed compared to using DIW.

[0062] Furthermore, in this specification, the statement "the nozzle is located directly above the center of the substrate W" is not limited to the nozzle being directly above the rotation center point of the substrate W. As long as the liquid sprayed from the nozzle and falling onto the surface of the substrate W can spread to the extent that it wets the rotation center point of the substrate W immediately afterwards, it is acceptable for the nozzle to be located away from the rotation center point of the substrate W.

[0063] Furthermore, in this embodiment, regardless of the type of liquid, a "liquid film" is formed as follows: liquid falling on the center of the rotating substrate W flows and diffuses towards the periphery of the substrate W by centrifugal force, thereby forming a "liquid film" on the surface of the substrate W. The thickness of the liquid film is basically determined by the rotational speed of the substrate W and the ejection flow rate of the liquid from the nozzle.

[0064] The cleanliness of DIW and dilute ammonia water used as pre-wetting solutions is higher than that of the chemical solution. High cleanliness means that the content of particulate matter (such as dust particles and substances that produce particles due to precipitation, etc.) is low.

[0065] [Initial thick film formation process (step S3)]

[0066] Next, stop spraying pre-wetting liquid (DIW) from rinsing nozzle 64 and retract rinsing nozzle 64 from a position directly above the center of substrate W, so that liquid nozzle 56 is positioned directly above the center of substrate W. Then, open on / off valve 54 to spray liquid from liquid nozzle 56 at a spray flow rate (e.g., a medium flow rate of about 700 mL / min) that is larger than the spray flow rate of the main processing step to be performed next (see reference). Figure 5 (c)). At approximately the same time as switching the liquid spray from the rinsing nozzle 64 to the liquid nozzle 56, the rotational speed of the substrate W is reduced to a value lower than the rotational speed in the pre-wetting process (e.g., an extremely low speed of about 30 rpm to 50 rpm).

[0067] The initial thick film formation process is continued until all the liquid substance that had been retained in the section immediately following the start of the initial thick film formation process, including the on / off valve 54 of the branch line 44 and its downstream side, is ejected from the liquid substance nozzle 56. Furthermore, from the viewpoint of saving liquid substance, increasing the total amount of liquid substance ejected in the initial thick film formation process is not preferable; therefore, the initial thick film formation process can also be continued until all the liquid substance retained in the section immediately following the on / off valve 54 of the branch line 44 and its downstream side is exactly discharged. For example, the initial thick film formation process is performed for approximately 10 seconds.

[0068] like Figure 6 As shown in the schematic diagram, in the early stage of the initial thick film formation process, a chemical solution is supplied from the chemical solution nozzle 56 onto a liquid film of a highly clean (virtually free of contaminants) pre-wetting liquid (DIW) formed through the pre-wetting process. At this time, for example, when the on / off valve 54 is opened, the valve body moves relative to the valve seat, which may generate dust that could be the cause of the aforementioned tiny particles. The dust (particles) generated here are supplied to the substrate W along with the chemical solution. The chemical solution containing this dust settles onto the liquid film of the pre-wetting liquid, which acts as a protective film. Although the chemical solution and the pre-wetting liquid diffuse with each other, the dust in the chemical solution is unlikely to reach the surface of the substrate W, and the dust hardly adheres to the surface of the substrate W. In other words, in the early stage of the initial thick film formation process, the protective effect of the liquid film of the pre-wetting liquid prevents dust from adhering to the substrate surface.

[0069] After the initial thick film formation process begins, over time, the pre-wetting solution is replaced by the chemical solution, and finally, as... Figure 7As shown in the schematic diagram, almost only liquid medicine exists on the surface of substrate W. The initial thick film formation process is performed under the condition that all liquid medicine remaining in the section between the on / off valve 54 and its downstream side of branch line 44 ends ejection from liquid medicine nozzle 56 at that time point. At the time point when all liquid medicine remaining in the section between the on / off valve 54 and its downstream side of branch line 44 ends ejection from liquid medicine nozzle 56, the liquid medicine ejected from liquid medicine nozzle 56 contains little to no dust from the valve (see reference). Figure 7 Even if the liquid sprayed from the liquid nozzle 56 contains some dust, because the liquid is supplied at a relatively high flow rate (e.g., 700 mL / min) during the initial thick film formation process, the liquid film thickness formed on the surface of the substrate W is relatively thick at the end of the initial thick film formation process. Therefore, the probability of dust in the liquid film coming into contact with the surface of the substrate W is low, and dust hardly adheres to the surface of the substrate W.

[0070] like Figure 8 As shown, the flow velocity of the liquid flowing from the center of substrate W towards the periphery decreases as it approaches the surface of substrate W and increases as it approaches the surface of the liquid film (the length of the arrow with the symbol V indicates the velocity). Near the substrate surface where the flow velocity is low, dust (particulate matter) contained in the liquid easily adheres to the surface of substrate W. When the liquid film is thin, most of the dust contained in the liquid moves at a low speed near the surface of substrate W, thus easily adhering to the surface of substrate W. Furthermore, once dust (especially the aforementioned tiny dust particles) adheres to the surface of substrate W, it is difficult for it to leave the surface of substrate W even when exposed to a low-flow-velocity liquid stream. When the liquid film is thick, most of the dust contained in the liquid flows towards the periphery of substrate W at a higher speed away from the surface of the substrate, thus the amount of dust adhering to the surface of substrate W is small. In other words, when supplying a liquid containing a certain amount of dust to substrate W, setting the rotation speed of substrate W to form a large flow rate and a thick film can better suppress the adhesion of dust (particulate matter). This situation is taken into account when determining the spray flow rate of the solution and the rotation speed of the substrate W in the initial thick film formation process.

[0071] Experiments were conducted to examine the conditions of the initial thick film formation process. When the substrate rotation speed was fixed at 50 rpm and the liquid injection flow rate was varied between 200 L / min and 700 mL / min, it was confirmed that a higher liquid injection flow rate resulted in a lower particle size adhering to the substrate. Furthermore, when the liquid injection flow rate was fixed at 200 mL / min and the substrate rotation speed was varied between 50 rpm and 300 rpm, it was confirmed that a lower substrate rotation speed resulted in a lower particle size adhering to the substrate. Therefore, it can be concluded that a greater liquid film thickness formed in the initial thick film formation process results in a lower particle size.

[0072] [Main Processing Step (Drug Solution Treatment) (Step S4)]

[0073] Next, while maintaining the rotational speed of the substrate W at an extremely low speed (e.g., the same speed as the initial thick film formation process), the flow rate of the liquid ejected from the liquid nozzle 56 is reduced to a small flow rate (e.g., 200 mL / min) to perform the main processing steps (see reference). Figure 5 (d) At this time, due to the reduced flow rate of the liquid solution, the thickness of the liquid film on the surface of the substrate W becomes thinner. Of course, the flow rate of the liquid solution is maintained at a value above that ensures the entire surface of the substrate W is seamlessly covered by the liquid film of the liquid solution. As an example, the main processing step is performed for about 70 to 80 seconds.

[0074] At the start of the main processing step, almost all dust (particles) from the valve has been ejected from the chemical nozzle, resulting in a higher cleanliness of the chemical solution supplied to the substrate W compared to the initial thick film formation step. Therefore, even with a thinner liquid film, dust adhesion to the surface of the substrate W can be prevented or sufficiently suppressed. The main processing step continues until the desired chemical treatment of the substrate W's surface is completed (e.g., until the desired etching amount is achieved). Maintaining a low chemical flow rate during the main processing step significantly reduces processing costs, especially when using expensive chemical solutions.

[0075] [Switching process (transfer from main processing process to rinsing process) (Step S5)]

[0076] Next, while maintaining the flow rate of the liquid from the liquid nozzle 56, the rinsing nozzle 64 is positioned directly above the center of the substrate W, and DIW (pure water) as the rinsing solution is ejected from the rinsing nozzle 64 at a medium flow rate (e.g., 700 mL / min), thereby increasing the rotation speed of the substrate to a low speed (e.g., 200 rpm) (see reference). Figure 5 (e)). At this time, by suppressing the spray flow rate of the rinsing liquid to a low level as described above, liquid splashing can be prevented. When liquid is supplied simultaneously from both nozzles (56, 64), liquid splashing occurs on the surface of the substrate W due to interference between the different liquid flows. The splashed liquid is bounced back by the cup and re-adheres to the surface of the substrate W, thus becoming a cause of particulate matter. However, liquid splashing can be prevented by suppressing the spray flow rate from each nozzle (56, 64) to a low level. In addition, by supplying liquid simultaneously from both nozzles (56, 64), even if the spray flow rate of the liquid from each nozzle is suppressed to a low level, the liquid film will not break and expose the surface of the substrate W. The duration of simultaneous spraying of liquid from the medicine nozzle 56 and the rinsing nozzle 64 can be set to approximately 10 seconds, for example.

[0077] [Rinsing process (step S6)]

[0078] Next, the ejection of the medicine from the medicine nozzle 56 is stopped, and the flow rate of the rinsing liquid from the rinsing nozzle 64 is increased to a high flow rate (e.g., 1500 mL / min), and the rotation speed of the substrate is increased to a high speed (e.g., 1000 rpm) (see reference). Figure 5 (f)). The rinsing process is carried out for a period of time, for example, about 30 seconds, during which the chemicals used in the main treatment process and the reaction products generated are sufficiently removed.

[0079] As long as no areas not covered by liquid are generated on the surface of the substrate W, a switching process can be skipped, and the process can be transferred directly from the main processing step to the rinsing step. In other words, it is also possible to start spraying DIW from the rinsing nozzle 64 at the same time or approximately simultaneously with stopping the spraying of liquid from the liquid nozzle 56.

[0080] [IPA replacement process (step S7)]

[0081] While maintaining the rotation speed of the substrate W at a high speed (e.g., 1000 rpm), stop ejecting DIW from the rinsing nozzle 64, and position the IPA nozzle 66 directly above the center of the substrate W, continuously ejecting IPA from the IPA nozzle 66 at a small flow rate of approximately 100 mL / min for about 0.5 seconds (see reference). Figure 5 (g)). Thereafter, the rotational speed of the substrate is reduced to a medium speed (e.g., 300 rpm), and while maintaining the IPA ejection flow rate from the IPA nozzle 66, the IPA nozzle 66 is reciprocated between a position directly above the center of the substrate W and a position directly above the periphery of the substrate W (see reference). Figure 5 (h)). Thus, the DIW located on the surface of the substrate W (including the recesses of the pattern) is replaced with IPA.

[0082] [Drying Process]

[0083] Next, the rotational speed of the substrate W is maintained or increased, and the ejection of IPA from the IPA nozzle 66 is stopped. This removes IPA from the surface of the substrate W, thereby drying the substrate W. Furthermore, this drying process is not described in [the following text is missing from the original extract]. Figure 4 The timing diagram shows that if substrate W is dry, its rotation is stopped. This completes the series of processes performed on the substrate. Afterward, the processed substrate W is removed from processing unit 16.

[0084] <Effects of the Implementation Method>

[0085] When a large flow rate of chemical solution is supplied to a rotating substrate during chemical treatment, a thick liquid film is formed, making it difficult for particles to adhere to the substrate surface for the reasons explained earlier. However, given the high cost of chemical solutions, it is necessary to reduce the amount of chemical solution consumed. Methods for reducing chemical solution consumption include reducing the amount of chemical solution supplied to the substrate or recycling and reusing the used chemical solution. In the latter case, there have been numerous instances in recent years where the particle reduction requirements have not been met.

[0086] In the above embodiments, by performing the pre-wetting process and the initial thick film formation process, even when the liquid containing the causative agent of tiny particles is sprayed onto the surface of the substrate, the chance of the causative agent of tiny particles contacting (i.e., adhering) with the substrate surface is significantly reduced. In the main processing step (liquid treatment), the liquid containing the causative agent of tiny particles is supplied to the substrate at a sufficiently low amount. Therefore, even if the thickness of the liquid film is reduced (i.e., even if the supply of liquid is reduced), tiny particles will not adhere to the substrate. According to the above embodiments, compared with the case where liquid treatment is always performed by spraying liquid at a high flow rate, the level of particles adhering to the substrate can be suppressed to the same level or below, and the total consumption of liquid can be reduced.

[0087] It should be considered that the embodiments disclosed herein are exemplary in all respects and not restrictive. The above embodiments may also be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

[0088] The substrate is not limited to semiconductor wafers, but can also be any type of substrate used in the field of semiconductor device manufacturing, such as glass substrates or ceramic substrates.

Claims

1. A substrate processing method, characterized in that, include: In the cleaning liquid film formation process, a cleaning liquid is supplied to the substrate while the substrate is rotated, so as to form a liquid film of the cleaning liquid on the surface of the substrate; In the first liquid treatment step, after the cleaning liquid film formation step, while the substrate is rotated at a first rotational speed, liquid is supplied to the substrate at a first supply flow rate from a liquid nozzle provided in a liquid supply unit for supplying liquid to the substrate, so as to form a liquid film of liquid of a first thickness on the surface of the substrate, thereby inhibiting the adhesion of particles to the surface of the substrate, and using the liquid to perform etching treatment on the substrate. as well as In the second chemical treatment step, following the first chemical treatment step, while rotating the substrate at a second rotational speed, the supply flow rate is reduced to a second supply flow rate, and the same chemical solution used in the first chemical treatment step is supplied to the substrate from the chemical nozzle to form a liquid film of the chemical solution of a second thickness on the surface of the substrate. The substrate is then etched using the chemical solution until the desired etching amount is obtained. The cleaning solution is a different liquid from the pharmaceutical solution used in the first and second pharmaceutical solution treatment steps, and the cleaning solution has a higher degree of cleanliness than the pharmaceutical solution. The first thickness is thicker than the second thickness.

2. The substrate processing method according to claim 1, characterized in that, The first rotational speed is higher than or equal to the second rotational speed.

3. The substrate processing method according to claim 1 or 2, characterized in that, The medicine supply unit further includes: a distribution line branching off from the circulation line of the medicine circulation system for supplying the medicine to the medicine nozzle; and an on / off valve disposed on the distribution line for cutting off the supply of the medicine from the circulation line to the medicine nozzle. The substrate processing method further includes a pseudo-dispensing step before the first liquid treatment step begins. In the pseudo-dispensing step, the on / off valve is opened to discharge at least the liquid that is retained in the dispensing pipeline from the on / off valve to the liquid nozzle to a predetermined discharge location.

4. The substrate processing method according to claim 1 or 2, characterized in that, The medicine supply unit further includes: a distribution line branching off from the circulation line of the medicine circulation system for supplying the medicine to the medicine nozzle; and an on / off valve disposed on the distribution line for cutting off the supply of the medicine from the circulation line to the medicine nozzle. The first liquid treatment process is performed at least until all the liquid in the distribution line from the opening / closing valve to the liquid nozzle is sprayed out from the liquid nozzle at least at the time point when the opening / closing valve is opened to start spraying the liquid from the liquid nozzle to the substrate.

5. The substrate processing method according to claim 3, characterized in that, The first liquid treatment process is performed at least until all the liquid in the distribution line from the opening / closing valve to the liquid nozzle is sprayed out from the liquid nozzle at least at the time point when the opening / closing valve is opened to start spraying the liquid from the liquid nozzle to the substrate.

6. A substrate processing apparatus, characterized in that, have: A substrate holding section that holds a substrate; A rotation drive unit that rotates the substrate holding unit; A cleaning fluid supply unit supplies cleaning fluid to the substrate held by the substrate holding unit; The liquid medicine supply unit supplies liquid medicine to the substrate held by the substrate holding unit; as well as The control unit controls the operation of the substrate processing apparatus to execute the substrate processing method according to any one of claims 1 to 5.

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