Substrate cleaning method and substrate cleaning apparatus

Abstract

A technology is provided that can sufficiently remove particles from a substrate even when using a cleaning solution with low cleanliness. A substrate processing method according to one aspect of the present disclosure includes a first cleaning process and a second cleaning process. The first cleaning process cleans the substrate with a first cleaning solution. The second cleaning process cleans the substrate with a second cleaning solution with lower cleanliness than the first cleaning solution after the first cleaning process.

Description

Technology Field

[0001] The disclosed embodiment relates to a substrate cleaning method and a substrate cleaning apparatus. Background Technology

[0002] Conventionally, a technology for cleaning a substrate such as a semiconductor wafer (hereinafter also referred to as a ‘wafer’) with a cleaning solution is known (see Patent Document 1). Prior art literature

[0003] Japanese Patent Publication No. 2007-258462 The problem to be solved

[0004] The present disclosure provides a technology capable of sufficiently removing particles from a substrate even when using a cleaning solution with low cleanliness. means of solving the problem

[0005] A substrate processing method according to one aspect of the present disclosure includes a first cleaning process and a second cleaning process. The first cleaning process cleans a substrate with a first cleaning solution. The second cleaning process cleans the substrate with a second cleaning solution having a lower degree of cleanliness than the first cleaning solution after the first cleaning process. Effects of the invention

[0006] According to the present disclosure, even when using a cleaning solution with low cleanliness, particles can be sufficiently removed from the substrate. Brief explanation of the drawing

[0007] Figure 1 is a schematic diagram showing the schematic configuration of a substrate processing system according to an embodiment. FIG. 2 is a schematic diagram showing an example of the configuration of a processing unit according to an embodiment. Figure 3 is a schematic diagram showing the piping configuration of a substrate processing system according to an embodiment. Figure 4 is a figure for explaining the sequence of substrate processing according to an embodiment. Figure 5 is a figure showing the difference in the supply timing of the recovered liquid and the new liquid in substrate processing according to the embodiment. Figure 6 is a figure showing the difference between DIW and functional water in rinsing treatment according to an embodiment. Figure 7 is a figure showing the difference in temperature of the recovered liquid in the filtration treatment according to the embodiment. FIG. 8 is a diagram illustrating the sequence of substrate processing according to Variant Example 1 of the embodiment. FIG. 9 is a diagram illustrating the sequence of substrate processing according to Variant Example 2 of the embodiment. FIG. 10 is a diagram illustrating the sequence of substrate processing according to Variant Example 3 of the embodiment. FIG. 11 is a schematic diagram showing the piping configuration of a substrate processing system according to a modified example 4 of an embodiment. FIG. 12 is a diagram illustrating the sequence of substrate processing according to Variant Example 4 of the embodiment. FIG. 13 is a schematic diagram showing the piping configuration of a substrate processing system according to a modified example 5 of an embodiment. FIG. 14 is a diagram illustrating the sequence of substrate processing according to Variant Example 5 of the embodiment. FIG. 15 is a schematic diagram showing the piping configuration of a substrate processing system according to a modified example 6 of an embodiment. FIG. 16 is a diagram illustrating the sequence of substrate processing according to Variant Example 6 of the embodiment. FIG. 17 is a flowchart showing the sequence of substrate processing performed by a substrate processing system according to an embodiment. Specific details for implementing the invention

[0008] Hereinafter, embodiments of the substrate processing method and substrate processing apparatus disclosed herein will be described in detail with reference to the attached drawings. Furthermore, the present disclosure is not limited by each embodiment shown below. Additionally, it should be noted that the drawings are schematic and that the relationships between the dimensions of each element and the ratios of each element may differ from reality. Furthermore, there may be parts in which the relationships between dimensions and ratios differ from one another.

[0009] A technology for cleaning substrates, such as semiconductor wafers (hereinafter also referred to as "wafers"), with a cleaning solution is known. In such cleaning processes, from the perspective of cost and other factors, the used cleaning solution is sometimes recovered and reused for cleaning.

[0010] Meanwhile, since the recovered cleaning solution had a lower cleanliness compared to the new cleaning solution, it was difficult to sufficiently remove particles from the substrate during the cleaning process.

[0011] Therefore, a technology capable of sufficiently removing particles from a substrate is expected, even when using a cleaning solution with low cleanliness.

[0012] <Overview of Substrate Processing System>

[0013] First, with reference to FIG. 1, the schematic configuration of a substrate processing system (1) according to an embodiment will be described. FIG. 1 is a diagram showing the schematic configuration of a substrate processing system (1) according to an embodiment. In addition, the substrate processing system (1) is an example of a substrate processing device. Hereinafter, in order to clarify the positional relationship, the X-axis, Y-axis, and Z-axis that are orthogonal to each other are defined, and the Z-axis forward direction is defined as the vertical upward direction.

[0014] As shown in FIG. 1, the substrate processing system (1) is equipped with an incoming / outgoing station (2) and a processing station (3). The incoming / outgoing station (2) and the processing station (3) are provided adjacent to each other.

[0015] The incoming / outgoing station (2) is equipped with a carrier placement section (11) and a return section (12). In the carrier placement section (11), a plurality of carriers (C) are arranged to receive a plurality of substrates, in an embodiment, a semiconductor wafer (W) (hereinafter referred to as 'wafer (W)') in a horizontal state.

[0016] The transport unit (12) is provided adjacent to the carrier placement unit (11) and is equipped with a substrate transport device (13) and a delivery unit (14) inside. The substrate transport device (13) is equipped with a wafer holding mechanism for holding a wafer (W). Additionally, the substrate transport device (13) is capable of movement in the horizontal and vertical directions and rotation around a vertical axis, and transports the wafer (W) between the carrier (C) and the delivery unit (14) using the wafer holding mechanism.

[0017] A processing station (3) is provided adjacent to a return section (12). The processing station (3) is equipped with a return section (15) and a plurality of processing units (16). A processing unit (16) is an example of a substrate processing section. A plurality of processing units (16) are arranged on both sides of the return section (15).

[0018] The transport unit (15) is equipped with a substrate transport device (17) inside. The substrate transport device (17) is equipped with a wafer holding mechanism for holding a wafer (W). Additionally, the substrate transport device (17) is capable of moving in the horizontal and vertical directions and rotating around a vertical axis, and transports the wafer (W) between the transfer unit (14) and the processing unit (16) using the wafer holding mechanism.

[0019] The processing unit (16) performs a predetermined substrate processing on the wafer (W) that is transported by the substrate transport device (17). Details of this processing unit (16) will be described later.

[0020] Additionally, the substrate processing system (1) is equipped with a control device (4). The control device (4) is, for example, a computer and is equipped with a control unit (18) and a memory unit (19). A program that controls various processes executed in the substrate processing system (1) is stored in the memory unit (19). The control unit (18) controls the operation of the substrate processing system (1) by reading and executing the program stored in the memory unit (19).

[0021] In addition, such a program may be recorded on a computer-readable storage medium and installed from the storage medium into the memory unit (19) of the control device (4). Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), a memory card, etc.

[0022] Additionally, the substrate processing system (1) is equipped with a first cleaning solution supply unit (5), a cleaning solution recovery unit (6), and a second cleaning solution supply unit (7). The first cleaning solution supply unit (5) supplies the first cleaning solution to the processing unit (16) when cleaning the wafer (W).

[0023] The cleaning solution recovery unit (6) recovers the cleaning solution used in the cleaning process of the wafer (W). The second cleaning solution supply unit (7) supplies the second cleaning solution to the processing unit (16) during the cleaning process of the wafer (W). This second cleaning solution is a cleaning solution with a lower degree of cleanliness than the first cleaning solution. Details of the first cleaning solution supply unit (5), the cleaning solution recovery unit (6), and the second cleaning solution supply unit (7) will be described later.

[0024] In the substrate processing system (1) configured as described above, first, the substrate transport device (13) of the incoming / outgoing station (2) extracts a wafer (W) from a carrier (C) placed in the carrier placement section (11) and places the extracted wafer (W) in the transfer section (14). The wafer (W) placed in the transfer section (14) is extracted from the transfer section (14) by the substrate transport device (17) of the processing station (3) and brought into the processing unit (16).

[0025] A wafer (W) brought into the processing unit (16) is processed by the processing unit (16), then removed from the processing unit (16) by the substrate transport device (17) and placed in the transfer unit (14). Then, the processed wafer (W) placed in the transfer unit (14) is returned to the carrier (C) of the carrier placement unit (11) by the substrate transport device (13).

[0026] <Composition of Processing Unit>

[0027] Next, the configuration of the processing unit (16) will be explained with reference to FIG. 2. FIG. 2 is a schematic diagram showing a specific configuration example of the processing unit (16). As shown in FIG. 2, the processing unit (16) is equipped with a chamber (20), a liquid processing section (30), an upper surface supply section (40), a recovery cup (50), and a lower surface supply section (60).

[0028] The chamber (20) accommodates at least some of the liquid processing unit (30), the upper supply unit (40), the recovery cup (50), and the lower supply unit (60). A Fan Filter Unit (FFU) (21) is provided in the ceiling of the chamber (20). The FFU (21) forms a downflow within the chamber (20).

[0029] The liquid treatment unit (30) is equipped with a holding unit (31), a support unit (32), and a driving unit (33), and performs liquid treatment on a placed wafer (W). The holding unit (31) holds the wafer (W) horizontally. The support unit (32) is a member extending in a vertical direction, and its base end is rotatably supported by the driving unit (33), and its tip end supports the holding unit (31) horizontally. The driving unit (33) rotates the support unit (32) around a vertical axis.

[0030] This liquid processing unit (30) rotates the holding unit (31) supported by the holding unit (32) by using the driving unit (33) to rotate the holding unit (32), thereby rotating the wafer (W) held by the holding unit (31).

[0031] On the upper surface of the holding section (31) provided by the liquid processing section (30), a holding member (31a) is provided to hold the wafer (W) from the side. The wafer (W) is held horizontally by this holding member (31a) in a state slightly separated from the upper surface of the holding section (31). Additionally, the wafer (W) is held in the holding section (31) with the surface on which substrate processing is performed facing upward.

[0032] The upper surface supply unit (40) supplies a processing fluid to the upper surface (hereinafter also referred to as the "outer surface") of the wafer (W). The upper surface supply unit (40) is equipped with nozzles (41a, 41b) positioned on the outer surface side of the wafer (W), an arm (42) that horizontally supports these nozzles (41a, 41b), and a pivoting and lifting mechanism (43) that pivots and raises the arm (42).

[0033] The nozzle (41a) is connected to the cleaning solution supply line (112). From the nozzle (41a), the cleaning solution supplied through the cleaning solution supply line (112) is discharged onto the outer surface of the wafer (W). The piping configuration of the substrate processing system (1), including this cleaning solution supply line (112), will be described later.

[0034] The nozzle (41b) is connected to the functional water supply line (44). From the nozzle (41b), functional water supplied through the functional water supply line (44) is discharged onto the surface of the wafer (W). This functional water is an alkaline rinse liquid, such as ammonia water, electrolytic ionized water, hydrogen water, ozone water, etc.

[0035] The functional water supply line (44) has, in order from the upstream side, a functional water supply source (44a), a valve (44b), a pressure regulating valve (44c), a flow meter (44d), and a valve (44e). The functional water supply source (44a) is, for example, a tank that stores functional water.

[0036] The pressure regulating valve (44c) adjusts the flow rate of functional water supplied to the functional water supply line (44) based on the flow rate of functional water measured by the flow meter (44d). That is, the pressure regulating valve (44c) performs feedback control based on the flow rate of functional water measured by the flow meter (44d).

[0037] Additionally, the functional water supply line (44) is branched between the flow meter (44d) and the valve (44e), and this branched line is connected to the nozzle (61b) of the supply unit (60) (see FIG. 4) via the valve (44f).

[0038] A recovery cup (50) is positioned to surround a holding member (31) and collects the processing liquid scattered from the wafer (W) by the rotation of the holding member (31). A drain port (51) is formed at the bottom of the recovery cup (50), and the processing liquid collected by the recovery cup (50) is discharged to the outside of the processing unit (16) through this drain port (51). Additionally, an exhaust port (52) is formed at the bottom of the recovery cup (50) to discharge gas supplied from the FFU (21) to the outside of the processing unit (16).

[0039] The lower supply unit (60) is inserted and penetrates into the hollow portion (32a) of the retaining unit (31) and the supporting unit (32) to supply a processing fluid to the lower surface of the wafer (W) (hereinafter also referred to as the ‘back surface’). The lower supply unit (60) is equipped with nozzles (61a, 61b) (see FIG. 4) disposed on the back surface of the wafer (W), an arm (62) (see FIG. 4) that horizontally supports these nozzles (61a, 61b), and a moving mechanism (63) that moves the arm (62).

[0040] The nozzle (61a) is connected to the branch line (153). From the nozzle (61a), a second cleaning solution supplied through the branch line (153) is discharged onto the back side of the wafer (W). Details of the branch line (153) will be described later.

[0041] The nozzle (61b) is connected to the functional water supply line (44). Functional water supplied from the nozzle (61b) through the functional water supply line (44) is discharged onto the back side of the wafer (W).

[0042] Piping Configuration of the Substrate Processing System

[0043] Next, the piping configuration of the substrate processing system (1) will be explained with reference to FIG. 3. FIG. 3 is a schematic diagram showing the piping configuration of the substrate processing system (1) according to an embodiment.

[0044] As shown in FIG. 3, a substrate processing system (1) according to an embodiment comprises a first cleaning solution supply unit (5), a processing unit (16), a cleaning solution recovery unit (6), and a second cleaning solution supply unit (7).

[0045] The first cleaning solution supply unit (5) supplies the first cleaning solution to the processing unit (16). In the embodiment, the first cleaning solution is a new, unused cleaning solution. Therefore, in the following description, the first cleaning solution is also referred to as the "new solution."

[0046] In addition, the cleaning solution used for the cleaning treatment according to the embodiment is an acidic cleaning solution such as DSP (a mixture of pure water, sulfuric acid, hydrofluoric acid, and hydrogen peroxide) or BHF (buffered hydrofluoric acid) or DHF (diluted hydrofluoric acid). The cleaning treatment according to the embodiment is performed, for example, to remove residual particles on the surface of a dry-etched wafer (W).

[0047] The first cleaning solution supply unit (5) has a first cleaning solution supply line (100), a tank (101), and a circulation line (102). The first cleaning solution supply line (100) supplies the first cleaning solution to the tank (101).

[0048] The first cleaning fluid supply line (100) has a first cleaning fluid source (100a) and a valve (100b) in sequence from the upstream side. The first cleaning fluid source (100a) is, for example, a tank that stores the first cleaning fluid (fresh fluid).

[0049] The tank (101) stores the first cleaning solution supplied from the first cleaning solution supply line (100). The circulation line (102) is a circulation line that comes out of the tank (101) and returns to the tank (101).

[0050] In the circulation line (102), based on the tank (101), a pump (103), a filter (104), a heater (105), a flow meter (106), a valve (107), a valve (108), and a pressure regulating valve (109) are provided in order from the upstream side.

[0051] The pump (103) forms a circulation flow of the first cleaning liquid that comes out of the tank (101), passes through the circulation line (102), and returns to the tank (101). The filter (104) removes contaminants, such as particles, contained in the first cleaning liquid circulating within the circulation line (102).

[0052] The heater (105) raises the temperature of the first cleaning solution circulating in the circulation line (102). The flow meter (106) measures the flow rate of the first cleaning solution circulating in the circulation line (102). The pressure regulating valve (109) controls the flow rate of the first cleaning solution circulating in the circulation line (102).

[0053] Additionally, the tank (101) is connected to the drain section (DR) via the valve (110), and the circulation line (102) is connected to the drain section (DR) via the valve (111). Accordingly, the control unit (18) (see FIG. 1) can control the valves (110, 111) to discharge the first cleaning liquid in the tank (101) or the circulation line (102) to the drain section (DR) when the first cleaning liquid in the tank (101) or the circulation line (102) is replaced, etc.

[0054] Additionally, a cleaning fluid supply line (112) is branched from between the valve (107) and the valve (108) in the circulation line (102). This cleaning fluid supply line (112) is interposed between the first cleaning fluid supply unit (5) and the processing unit (16), and supplies the first cleaning fluid, which has undergone filtration treatment and temperature adjustment treatment in the first cleaning fluid supply unit (5), to the processing unit (16).

[0055] In the cleaning fluid supply line (112), a junction section (113), a flow meter (114), a pressure regulating valve (115), and a valve (116) are provided in order from the upstream side. A second cleaning fluid supply line (152) is connected to the junction section (113), and a second cleaning fluid is supplied from the second cleaning fluid supply section (7), which will be described in detail later.

[0056] That is, the cleaning solution supply line (112) can supply the first cleaning solution from the first cleaning solution supply unit (5) to the processing unit (16), and can also supply the second cleaning solution from the second cleaning solution supply unit (7) to the processing unit (16).

[0057] The flow meter (114) measures the flow rate of the first cleaning solution or the second cleaning solution flowing through the cleaning solution supply line (112). The pressure regulating valve (115) controls the flow rate of the first cleaning solution or the second cleaning solution flowing through the cleaning solution supply line (112).

[0058] Additionally, the cleaning fluid supply line (112) is connected to the drain section (DR) via a valve (117). Accordingly, the control unit (18) can control the valve (117) to discharge the cleaning fluid in the cleaning fluid supply line (112) to the drain section (DR) when the cleaning fluid in the cleaning fluid supply line (112) is replaced, etc.

[0059] The drain port (51) (see FIG. 2) of the processing unit (16) is connected to the cleaning solution recovery unit (6) via the discharge line (120). By doing so, the cleaning solution used for cleaning the wafer (W) within the processing unit (16) can be discharged to the cleaning solution recovery unit (6).

[0060] The cleaning solution recovery unit (6) recovers the cleaning solution used for cleaning the wafer (W) within the processing unit (16). The cleaning solution recovery unit (6) has a tank (121) connected to a discharge line (120) and a circulation line (122).

[0061] The tank (121) stores the cleaning solution that has been used in the processing unit (16). The circulation line (122) is a circulation line that comes out of the tank (121) and returns to the tank (121).

[0062] In the circulation line (122), based on the tank (121), a pump (123), a chiller (124), a filter (125), a flow meter (126), a valve (127), a valve (128), and a pressure regulating valve (129) are provided in order from the upstream side.

[0063] The pump (123) forms a circulation flow of used cleaning liquid that comes out of the tank (121), passes through the circulation line (122), and returns to the tank (121). The chiller (124) cools the used cleaning liquid circulating within the circulation line (122).

[0064] The filter (125) removes contaminants, such as particles, contained in the used cleaning solution cooled in the chiller (124). In an embodiment, the used cleaning solution cooled in the chiller (124) can be reused for cleaning treatment of the wafer (W) by filtering it through the filter (125).

[0065] The flow meter (126) measures the flow rate of the used cleaning solution circulating within the circulation line (122). The pressure regulating valve (129) controls the flow rate of the used cleaning solution circulating within the circulation line (122).

[0066] Additionally, the tank (121) is connected to the drain section (DR) via the valve (130), and the circulation line (122) is connected to the drain section (DR) via the valve (131). Accordingly, the control unit (18) can control the valves (130, 131) when replacing the used cleaning fluid in the tank (121) or the circulation line (122), and discharge the used cleaning fluid in the tank (121) or the circulation line (122) to the drain section (DR).

[0067] Additionally, a branch line (132) is branched from between the filter (125) and the flow meter (126) in the circulation line (122). This branch line (132) is interposed between the cleaning solution recovery unit (6) and the second cleaning solution supply unit (7) to supply the used cleaning solution, which has been filtration-treated in the cleaning solution recovery unit (6), to the second cleaning solution supply unit (7).

[0068] A valve (133), a filter (134), and a valve (135) are provided in sequence from the upstream side in the branch line (132). The filter (134) removes contaminants, such as particles, contained in the used cleaning liquid flowing through the branch line (132).

[0069] The second cleaning solution supply unit (7) supplies the used cleaning solution, which has been filtration-treated in the cleaning solution recovery unit (6), to the processing unit (16) as the second cleaning solution. This second cleaning solution has a lower cleanliness level than the unused first cleaning solution because, although it has been filtration-treated in the cleaning solution recovery unit (6), it is a cleaning solution that has already been used in the processing unit (16). In addition, in the following description, the second cleaning solution is also referred to as the "recovered solution."

[0070] The second cleaning solution supply unit (7) has a tank (141) connected to a branch line (132) and a circulation line (142). The tank (141) stores the second cleaning solution that has been filtration-treated in the cleaning solution recovery unit (6). The circulation line (142) is a circulation line that comes out of the tank (141) and returns to the tank (141).

[0071] In the circulation line (142), based on the tank (141), a pump (143), a filter (144), a heater (145), a flow meter (146), a valve (147), a valve (148), and a pressure regulating valve (149) are provided in order from the upstream side.

[0072] The pump (143) forms a circulation flow of a second cleaning solution that comes out of the tank (141), passes through the circulation line (142), and returns to the tank (141). The filter (144) removes contaminants, such as particles, contained in the second cleaning solution circulating within the circulation line (142).

[0073] The heater (145) heats the second cleaning solution circulating in the circulation line (142). The flow meter (146) measures the flow rate of the second cleaning solution circulating in the circulation line (142). The pressure regulating valve (149) controls the flow rate of the second cleaning solution circulating in the circulation line (142).

[0074] Additionally, the tank (141) is connected to the drain section (DR) via the valve (150), and the circulation line (142) is connected to the drain section (DR) via the valve (151). Accordingly, the control unit (18) can control the valves (150, 151) when replacing the second cleaning fluid in the tank (141) or the circulation line (142), and discharge the second cleaning fluid in the tank (141) or the circulation line (142) to the drain section (DR).

[0075] Additionally, a second cleaning fluid supply line (152) is branched from between the valve (147) and the valve (148) in the circulation line (142). This second cleaning fluid supply line (152) is interposed between the second cleaning fluid supply unit (7) and the confluence (113) of the cleaning fluid supply line (112), and supplies the second cleaning fluid, which has been temperature-controlled in the second cleaning fluid supply unit (7), to the cleaning fluid supply line (112).

[0076] Additionally, a branch line (153) branches off from the second cleaning solution supply line (152). This branch line (153) is connected to the lower surface supply unit (60) (see FIG. 2) of the processing unit (16), and supplies the second cleaning solution, which has been temperature-controlled in the second cleaning solution supply unit (7), to this lower surface supply unit (60).

[0077] In the branch line (153), a flow meter (154), a pressure regulating valve (155), and a valve (156) are provided in order from the upstream side. The flow meter (154) measures the flow rate of the second cleaning liquid circulating within the branch line (153). The pressure regulating valve (155) controls the flow rate of the second cleaning liquid circulating within the branch line (153).

[0078] Substrate Processing

[0079] Next, details of the substrate processing according to the embodiment will be explained with reference to FIGS. 4 to 7. FIG. 4 is a figure illustrating the sequence of substrate processing according to the embodiment.

[0080] For a dry-etched wafer (W), the substrate processing system (1) (see FIG. 2) controls the nozzle (41a) as shown in FIG. 4 (a) to perform a first cleaning treatment to clean the outer surface of the wafer (W) with a first cleaning solution (new solution). Through this first cleaning treatment, the substrate processing system (1) can remove particles attached to the outer surface of the wafer (W).

[0081] In addition, during this first cleaning process, the substrate processing system (1) controls the nozzle (61a) to clean the back side of the wafer (W) with the second cleaning solution (recovery solution). By doing so, the substrate processing system (1) can remove particles attached to the back side of the wafer (W).

[0082] Next, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 4 (b) to perform a second cleaning process, which cleans the outer surface of the wafer (W) with a second cleaning solution (recovery solution). Through this second cleaning process, the substrate processing system (1) can remove particles on the outer surface that could not be removed by the first cleaning process.

[0083] In addition, during this second cleaning process, the substrate processing system (1) then cleans the back side of the wafer (W) with the second cleaning solution (recovery solution).

[0084] Next, the substrate processing system (1) controls the nozzle (41b) as shown in (c) of FIG. 4 to perform a rinsing treatment to rinse the outer surface of the wafer (W) with functional water. Through this rinsing treatment, the substrate processing system (1) can remove the cleaning solution remaining on the outer surface of the wafer (W).

[0085] In addition, during this rinsing process, the substrate processing system (1) controls the nozzle (61b) to rinse the back side of the wafer (W) with functional water. By doing so, the substrate processing system (1) can remove the cleaning solution remaining on the back side of the wafer (W).

[0086] Finally, the substrate processing system (1) controls the liquid processing unit (30) (see FIG. 2) to perform a drying process (e.g., spin drying) on ​​the wafer (W) (not shown).

[0087] As explained above, in the embodiment, when removing particles attached to the outer surface of the wafer (W), the outer surface of the wafer (W) is first cleaned with a fresh liquid with high purity, and then the outer surface of the wafer (W) is cleaned with a recovered liquid with low purity.

[0088] Here, the relationship between the timing of supplying both cleaning solutions and the particles remaining on the wafer (W) is shown when fresh solutions and recovered solutions are used separately in the cleaning process of the wafer (W). FIG. 5 is a figure showing the difference in the timing of supplying the recovered solution and fresh solution in the substrate processing according to an embodiment.

[0089] In addition, the example in FIG. 5 is the result when the flow rate of the cleaning solution discharged on the outer surface of the wafer (W) is set to 1500 (mL / min), the flow rate of the cleaning solution discharged on the back surface of the wafer (W) is set to 1000 (mL / min), and the processing time by the cleaning solution is set to 30 seconds.

[0090] As shown in Fig. 5, when the recovery solution is used throughout the entire cleaning process (30 seconds), the number of particles remaining on the wafer (W) after cleaning increases because the cleanliness of the recovery solution is low.

[0091] In addition, even if the recovered solution is used during the first period (23 seconds) of the cleaning process and the new solution is used during the next period (7 seconds), the number of particles remaining on the wafer (W) after cleaning is almost unchanged compared to when the recovered solution is used throughout the entire period.

[0092] This is presumed to be because if a recovery solution with low cleanliness is used during the first period, particles adhere firmly to the wafer (W) during this first period, and even if a new solution is used during the next period, it is difficult to remove the firmly adhered particles.

[0093] Meanwhile, as shown in the above-described embodiment, if a fresh liquid is used during the first period (5 seconds), a recovered liquid is used during the next period (23 seconds), and a fresh liquid is used during the last period (2 seconds), the number of particles remaining on the wafer (W) is significantly reduced, even though the length of the fresh liquid itself remains unchanged.

[0094] This is presumed to be because, by using a fresh liquid with high purity during the initial period, particles can be efficiently removed, thereby preventing them from adhering firmly to the wafer (W).

[0095] In this way, in the embodiment, by using a fresh liquid with high cleanliness during the first period of the cleaning treatment and using a recovered liquid with low cleanliness during the next period, particles can be sufficiently removed from the outer surface of the wafer (W) even when a recovered liquid with low cleanliness is used.

[0096] In addition, in the embodiment, the amount of fresh liquid required for the cleaning process can be reduced because the recovered liquid can be used for the cleaning process. Therefore, according to the embodiment, the cost of the cleaning process can be reduced.

[0097] In addition, as shown in FIG. 4, in the cleaning treatment according to the embodiment, since the amount of particles attached to the back surface of the wafer (W) is smaller than that on the front surface, there is no practical problem even if the back surface is cleaned with a recovery solution with low cleanliness.

[0098] In addition, by cleaning the back side of the wafer (W) with the recovery solution over the entire period, the amount of fresh solution required for the cleaning process can be further reduced, thereby further reducing the cost of the cleaning process.

[0099] In addition, in the embodiment, functional water may be used for rinsing treatment. FIG. 6 is a figure showing the difference between DIW and functional water in rinsing treatment according to the embodiment.

[0100] In addition, the example in Fig. 6 is the result of using diluted ammonia water with a concentration of 3 (ppmw) and a temperature of 25°C as the functional water, in addition to the same conditions as the example in Fig. 5, and setting the flow rate of DIW and functional water discharged on the outer and back surfaces of the wafer (W) to 1500 (mL / min).

[0101] As shown in FIG. 6, compared to the case where DIW is used for rinsing treatment, the number of particles remaining on the wafer (W) can be reduced by using functional water for rinsing treatment.

[0102] This result is presumed to be due to the following reasons. In terms of zeta potential, by using alkaline functional water for rinsing treatment, the surface of particles remaining on the wafer (W) can be negatively charged.

[0103] In addition, since the surface of the wafer (W) composed of silicon is negatively charged, in the embodiment, the attachment of negatively charged particles can be suppressed by the functional water.

[0104] In addition, although the embodiment shows a case where the rinsing treatment was performed with functional water, the rinsing treatment may also be performed with an alkaline treatment solution (e.g., SC1 (a mixture of ammonia and hydrogen peroxide)).

[0105] Accordingly, in addition to the effect of negatively charging the particles, the effect of removing particles attached to the surface oxide film is obtained by finely etching the surface oxide film of the wafer (W). Therefore, by performing the rinsing treatment with an alkaline etching solution, the number of particles remaining on the wafer (W) can be further reduced.

[0106] In addition, in the embodiment, the filtration treatment of the cleaning solution (e.g., recovery solution) may be carried out at a temperature lower than room temperature (25°C). FIG. 7 is a figure showing the difference in temperature of the recovery solution during the filtration treatment according to the embodiment.

[0107] In addition, the example in FIG. 7 is the result when the flow rate of the cleaning solution discharged on the outer surface of the wafer (W) is set to 1500 (mL / min), the flow rate of the cleaning solution discharged on the back surface of the wafer (W) is set to 1000 (mL / min), and the processing time by the cleaning solution is set to 250 seconds.

[0108] As shown in FIG. 7, compared to when the filtration treatment is performed at room temperature (25°C), the number of particles remaining on the wafer (W) can be reduced by performing the filtration treatment at a temperature lower than room temperature (20°C, 18°C).

[0109] This result is presumed to be due to the following reasons. In filtration treatment at a temperature lower than room temperature (hereinafter also referred to simply as 'low temperature'), the membrane inside the filter (125) (see FIG. 3) shrinks compared to filtration treatment at room temperature.

[0110] Accordingly, as the diameter of the membrane is narrowed, smaller particles can be captured by the filter (125). Therefore, according to the embodiment, the filtration capability of the filter (125) can be improved.

[0111] In addition, in filtration treatment at low temperature, the amount of particles leached from the membrane of the filter (125) can be reduced compared to filtration treatment at room temperature. By doing so, the filtration ability of the filter (125) can also be improved.

[0112] Various Variations

[0113] Next, various variations of the embodiment will be described with reference to FIGS. 8 to 16. FIG. 8 is a diagram illustrating the sequence of substrate processing according to Variation 1 of the embodiment. In addition, for subsequent examples, the description of processing identical to that of the embodiment shown in FIG. 4 will be omitted.

[0114] For a dry-etched wafer (W), the substrate processing system (1) (see FIG. 2) controls the nozzle (41a) as shown in FIG. 8 (a) to clean the outer surface of the wafer (W) with a first cleaning solution (new solution). Then, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 8 (b) to clean the outer surface of the wafer (W) with a second cleaning solution (recovery solution).

[0115] Next, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 8 (c) to clean the outer surface of the wafer (W) with a first cleaning solution (new solution). Then, the substrate processing system (1) controls the nozzle (41b) as shown in FIG. 8 (d) to rinse the outer surface of the wafer (W) with functional water. Finally, the substrate processing system (1) performs a drying treatment on the wafer (W) (not shown).

[0116] That is, in Variation Example 1, a cleaning treatment using a first cleaning solution is added between the second cleaning treatment and the rinsing treatment according to the embodiment. By doing so, particles on the surface that could not be removed by the second cleaning treatment can be removed.

[0117] Therefore, according to Variation Example 1, even when using a recovery solution with low cleanliness, particles can be more sufficiently removed from the outer surface of the wafer (W).

[0118] FIG. 9 is a diagram illustrating the sequence of substrate processing according to Variation Example 2 of the embodiment. With respect to a dry-etched wafer (W), the substrate processing system (1) (see FIG. 2) controls the nozzle (41a) as shown in FIG. 9 (a) to clean the outer surface of the wafer (W) with a first cleaning solution (new solution).

[0119] Next, the substrate processing system (1) controls the nozzle (41b) as shown in FIG. 9 (b) to rinse the outer surface of the wafer (W) with functional water. Then, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 9 (c) to clean the outer surface of the wafer (W) with a first cleaning solution (new solution).

[0120] Next, the substrate processing system (1) controls the nozzle (41b) as shown in (d) of FIG. 9 to rinse the outer surface of the wafer (W) with functional water. Finally, the substrate processing system (1) performs a drying treatment on the wafer (W) (not shown).

[0121] That is, in Variation Example 2, a rinsing treatment is added during the two cleaning treatments with the first cleaning solution. By doing so, particles on the surface that could not be removed by the initial cleaning treatment with the first cleaning solution can be removed. Therefore, according to Variation Example 2, particles can be sufficiently removed from the surface of the wafer (W).

[0122] FIG. 10 is a diagram illustrating the sequence of substrate processing according to Variant Example 3 of the embodiment. With respect to a dry-etched wafer (W), the substrate processing system (1) (see FIG. 2) controls the nozzle (41a) as shown in FIG. 10 (a) to clean the outer surface of the wafer (W) with a first cleaning solution (new solution).

[0123] Next, the substrate processing system (1) controls the nozzle (41b) as shown in FIG. 10 (b) to rinse the outer surface of the wafer (W) with functional water. Then, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 10 (c) to clean the outer surface of the wafer (W) with a second cleaning solution (recovery solution).

[0124] Next, the substrate processing system (1) controls the nozzle (41b) as shown in (d) of FIG. 10 to rinse the outer surface of the wafer (W) with functional water. Finally, the substrate processing system (1) performs a drying treatment on the wafer (W) (not shown).

[0125] That is, in Variation Example 3, a rinsing treatment is added between the first cleaning treatment and the second cleaning treatment according to the embodiment. By doing so, surface particles that could not be removed by the first cleaning treatment can be removed.

[0126] Therefore, according to Variation Example 3, even when using a recovery solution with low cleanliness, particles can be more sufficiently removed from the outer surface of the wafer (W).

[0127] FIG. 11 is a schematic diagram showing the piping configuration of a substrate processing system (1) according to a modified example 4 of the embodiment. As shown in FIG. 11, the substrate processing system (1) according to modified example 4 differs from the above-described embodiment in that a second cleaning liquid supply line (136) is provided to supply a second cleaning liquid from a cleaning liquid recovery unit (6) to a processing unit (16). Therefore, in the following examples, the same reference numerals are assigned to parts identical to those in FIG. 3, and the description is omitted.

[0128] The second cleaning fluid supply line (136) branches off from between the filter (134) and the valve (135) in the branch line (132). Additionally, a junction (157) is provided in the second cleaning fluid supply line (152), and the second cleaning fluid supply line (136) is connected to this junction (157).

[0129] Accordingly, the substrate processing system (1) according to modified example 4 can supply the recovered liquid, which has been filtration-treated at a low temperature in the cleaning liquid recovery unit (6), to the processing unit (16) while remaining at a low temperature.

[0130] FIG. 12 is a diagram illustrating the sequence of substrate processing according to Variant Example 4 of the embodiment. With respect to a dry-etched wafer (W), the substrate processing system (1) (see FIG. 11) controls the nozzle (41a) as shown in FIG. 12 (a) to clean the outer surface of the wafer (W) with a high-temperature first cleaning solution (new solution). This high-temperature new solution can be generated by heating the new solution with the heater (105) (see FIG. 11) of the first cleaning solution supply unit (5).

[0131] In this way, by cleaning the outer surface of the wafer (W) with a high-temperature fresh liquid, the etching rate can be increased in cases where the surface of the wafer (W) is etched with such a cleaning liquid, such as when using a DSP as the cleaning liquid.

[0132] Next, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 12 (b) to clean the outer surface of the wafer (W) with a second cleaning solution (recovery solution) at a low temperature. This low-temperature recovery solution is supplied from the cleaning solution recovery unit (6) through the second cleaning solution supply line (136).

[0133] In this way, by cleaning the outer surface of the wafer (W) with a low-temperature recovery solution, the etching rate can be reduced when the surface of the wafer (W) is etched by the cleaning solution. By doing so, the total etching amount can be adjusted to a reduced value by combining the cleaning treatment with a high-temperature fresh solution and the cleaning treatment with a low-temperature recovery solution.

[0134] Next, the substrate processing system (1) controls the nozzle (41b) as shown in (c) of FIG. 12 to rinse the outer surface of the wafer (W) with functional water. Finally, the substrate processing system (1) performs a drying treatment on the wafer (W) (not shown).

[0135] FIG. 13 is a schematic diagram showing the piping configuration of a substrate processing system (1) according to a modified example 5 of the embodiment. As shown in FIG. 13, the substrate processing system (1) according to modified example 5 differs from the embodiment in that a chiller (118) is provided in the circulation line (102) of the first cleaning liquid supply unit (5) instead of a heater (105).

[0136] This chiller (118) is provided between the pump (103) and the filter (104) in the circulation line (102) and cools the first cleaning liquid (new liquid) circulating in the circulation line (102).

[0137] In Variation Example 5, by using a chiller (118), the filtration treatment of the first cleaning solution can be performed at a temperature lower than room temperature. Therefore, according to Variation Example 5, the number of particles remaining on the wafer (W) can be further reduced as the cleanliness of the first cleaning solution can be further improved.

[0138] In addition, in Variation Example 5, the fresh liquid that has been filtration-treated at a low temperature in the first cleaning liquid supply unit (5) can be supplied to the treatment unit (16) while remaining at a low temperature.

[0139] FIG. 14 is a diagram illustrating the sequence of substrate processing according to Variant Example 5 of the embodiment. With respect to a dry-etched wafer (W), the substrate processing system (1) (see FIG. 13) controls the nozzle (41a) as shown in FIG. 14 (a) to clean the outer surface of the wafer (W) with a first cleaning solution (fresh solution) at a low temperature. This low-temperature fresh solution is supplied from the first cleaning solution supply unit (5).

[0140] In this way, by cleaning the outer surface of the wafer (W) with a low-temperature fresh solution, it is possible to make it difficult for particles to adhere to the wafer (W) when the surface of the wafer (W) is etched with such a cleaning solution, such as when using a DSP as a cleaning solution.

[0141] Next, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 14 (b) to clean the outer surface of the wafer (W) with a second high-temperature cleaning solution (recovery solution). This high-temperature recovery solution can be generated by heating the recovery solution with the heater (145) of the second cleaning solution supply unit (7).

[0142] In this way, by cleaning the outer surface of the wafer (W) with a high-temperature recovery solution, the etching rate can be increased when the surface of the wafer (W) is etched by the cleaning solution. By doing so, the total etching amount can be adjusted to a reduced value by combining the cleaning treatment with a low-temperature fresh solution and the cleaning treatment with a high-temperature recovery solution.

[0143] Next, the substrate processing system (1) controls the nozzle (41b) as shown in (c) of FIG. 14 to rinse the outer surface of the wafer (W) with functional water. Finally, the substrate processing system (1) performs a drying treatment on the wafer (W) (not shown).

[0144] In the embodiments and various modifications described so far, cases in which an unused cleaning solution (i.e., a new solution) is used as the first cleaning solution have been shown, but the first cleaning solution according to the embodiments is not limited to an unused cleaning solution.

[0145] FIG. 15 is a schematic diagram showing the piping configuration of a substrate processing system (1) according to a modified example 6 of the embodiment. As shown in FIG. 15, the substrate processing system (1) according to modified example 6 is different from modified example 4 in that the branch line (132) is connected only to the junction (157), and the branch line (137) is branched from the discharge line (120) and this branch line (137) is connected to the second cleaning liquid supply unit (7).

[0146] A branch line (137) is provided interposed between the treatment unit (16) and the tank (141) of the second cleaning liquid supply unit (7) via a discharge line (120). By providing such a branch line (137), the cleaning liquid that has been used in the treatment unit (16) can be directly supplied to the second cleaning liquid supply unit (7).

[0147] Accordingly, according to Variation Example 6, the cleaning solution that has been used in the processing unit (16) can be filtration treated at room temperature or a temperature higher than room temperature (hereinafter also simply referred to as 'high temperature') in the second cleaning solution supply unit (7).

[0148] In addition, in Variant Example 6, the branch line (132) is connected to the confluence section (157), so that the recovered liquid, which has been filtration-treated at a low temperature in the cleaning liquid recovery section (6), can be directly supplied to the processing unit (16).

[0149] FIG. 16 is a diagram illustrating the sequence of substrate processing according to Variant Example 6 of the embodiment. For a dry-etched wafer (W), the substrate processing system (1) (see FIG. 15) controls the nozzle (41a) as shown in FIG. 16 (a) to clean the outer surface of the wafer (W) with a recovery liquid filtrationed at a low temperature.

[0150] Next, the substrate processing system (1) controls the nozzle (41a) as shown in FIG. 16 (b) to clean the outer surface of the wafer (W) with a filtration-treated recovery liquid at room temperature. Then, the substrate processing system (1) controls the nozzle (41b) as shown in FIG. 16 (c) to rinse the outer surface of the wafer (W) with functional water. Finally, the substrate processing system (1) performs a drying treatment on the wafer (W) (not shown).

[0151] In this modified example 6, the recovered liquid filtration at low temperature has a higher degree of cleanliness than the recovered liquid filtration at room temperature. That is, in modified example 6, the recovered liquid filtration at low temperature becomes the first cleaning liquid, and the recovered liquid filtration at room temperature becomes the second cleaning liquid.

[0152] In this variation of Example 6, a cleaning treatment is first performed with a first cleaning solution with high purity, and then a cleaning treatment is performed with a second cleaning solution with low purity. By doing so, even when using a recovery solution with low purity that has been filtration-treated at room temperature, particles can be sufficiently removed from the outer surface of the wafer (W).

[0153] In addition, in Variant Example 6, the amount of fresh liquid required for the cleaning treatment can be further reduced because the recovered liquid can be used throughout the entire cleaning treatment period. Therefore, according to Variant Example 6, the cost of the cleaning treatment can be further reduced.

[0154] In this way, in the present disclosure, a cleaning solution with a higher degree of cleanliness than the second cleaning solution may be used as the first cleaning solution. For example, a fresh solution treated with filtration at a low temperature may be used as the first cleaning solution, and a fresh solution treated with filtration at room temperature or a high temperature may be used as the second cleaning solution.

[0155] In addition, a fresh solution treated with filtration at low temperature may be used as a first cleaning solution, and a recovered solution treated with filtration at low temperature, room temperature, or high temperature may be used as a second cleaning solution.

[0156] In addition, a fresh solution treated with filtration at room temperature or high temperature may be used as a first cleaning solution, and a recovered solution treated with filtration at low temperature, room temperature, or high temperature may be used as a second cleaning solution. In addition, a recovered solution treated with filtration at room temperature may be used as a first cleaning solution, and a recovered solution treated with filtration at high temperature may be used as a second cleaning solution.

[0157] A substrate processing device (substrate processing system (1)) according to an embodiment comprises a substrate processing unit (processing unit (16)), a first cleaning solution supply unit (5), a cleaning solution recovery unit (6), and a second cleaning solution supply unit (7). The substrate processing unit (processing unit (16)) processes a substrate (wafer (W)). The first cleaning solution supply unit (5) supplies unused cleaning solution to the substrate processing unit (processing unit (16)). The cleaning solution recovery unit (6) recovers the cleaning solution used in the substrate processing unit (processing unit (16)). The second cleaning solution supply unit (7) supplies the used cleaning solution recovered from the cleaning solution recovery unit (6) to the substrate processing unit (processing unit (16)). By doing so, even if a recovery solution with low cleanliness is used, particles can be sufficiently removed from the wafer (W).

[0158] Additionally, the substrate processing device (substrate processing system (1)) according to the embodiment further comprises a substrate processing unit (processing unit (16)), a first cleaning solution supply unit (5), a cleaning solution recovery unit (6), and a control unit (18) that controls the second cleaning solution supply unit (7). After supplying unused cleaning solution from the first cleaning solution supply unit (5), the control unit (18) supplies used cleaning solution from the second cleaning solution supply unit (7). By doing so, even when using a recovery solution with low cleanliness, particles can be sufficiently removed from the wafer (W).

[0159] In addition, in a substrate processing device (substrate processing system (1)) according to an embodiment, the cleaning solution recovery unit (6) has a filter (125) that filters the recovered cleaning solution, and the filter (125) filters the recovered cleaning solution at a temperature lower than room temperature. By doing so, the number of particles remaining on the wafer (W) can be reduced.

[0160] <Sequence of Substrate Processing>

[0161] Next, the sequence of substrate processing according to the embodiment will be explained with reference to FIG. 17. FIG. 17 is a flowchart showing the sequence of substrate processing performed by the substrate processing system (1) according to the embodiment.

[0162] First, the control unit (18) controls the first cleaning solution supply unit (5) and the processing unit (16) to perform a first cleaning process of cleaning the wafer (W) with the first cleaning solution (step (S101)). Subsequently, the control unit (18) controls the second cleaning solution supply unit (7) and the processing unit (16) to perform a second cleaning process of cleaning the wafer (W) with a second cleaning solution having a lower cleanliness level than the first cleaning solution (step (S102)).

[0163] Next, the control unit (18) controls the functional water supply line (44) and the processing unit (16) to perform a rinsing treatment of the wafer (W) with the functional water (step (S103)). Then, the control unit (18) controls the liquid processing unit (30) to perform a drying treatment of the wafer (W) (step (S104)). When this step (S104) is completed, the series of treatments is completed.

[0164] A substrate processing method according to an embodiment includes a first cleaning process (step (S101)) and a second cleaning process (step (S102)). The first cleaning process (step (S101)) cleans the substrate (wafer (W)) with a first cleaning solution. The second cleaning process (step (S102)) cleans the substrate (wafer (W)) with a second cleaning solution having a lower cleanliness level than the first cleaning solution after the first cleaning process (step (S101)). By doing so, even when using a cleaning solution with a lower cleanliness level, particles can be sufficiently removed from the wafer (W).

[0165] In addition, in the substrate processing method according to the embodiment, the first cleaning solution is an unused cleaning solution, and the second cleaning solution is a used cleaning solution. By doing so, the cost of the cleaning process can be reduced in that the amount of new solution required for the cleaning process can be reduced.

[0166] In addition, in the substrate processing method according to the embodiment, the second cleaning solution is a cleaning solution that is filtered at a temperature lower than room temperature after use. By doing so, the number of particles remaining on the wafer (W) can be reduced in order to improve the cleanliness of the second cleaning solution.

[0167] In addition, in the substrate processing method according to the embodiment, the first cleaning solution is a cleaning solution that is filtered at a temperature lower than room temperature while remaining unused. By doing so, the number of particles remaining on the wafer (W) can be further reduced in order to further improve the cleanliness of the first cleaning solution.

[0168] In addition, in the substrate treatment method according to the embodiment, the first cleaning solution is a cleaning solution filtered at a temperature lower than room temperature after use, and the second cleaning solution is a cleaning solution filtered at a temperature higher than room temperature after use. By doing so, the amount of fresh solution required for the cleaning treatment can be further reduced in that the recovered solution can be used throughout the entire cleaning treatment period.

[0169] In addition, the substrate processing method according to the embodiment further includes a rinsing process (step (S103)) in which the substrate (wafer (W)) is rinsed with functional water after the second cleaning process (step (S102)). By doing so, the number of particles remaining on the wafer (W) can be reduced.

[0170] In addition, in the substrate processing method according to the embodiment, the first cleaning process (step (S101)) cleans the substrate (wafer (W)) with a first cleaning solution at a temperature higher than room temperature, and the second cleaning process (step (S102)) cleans the substrate (wafer (W)) with a second cleaning solution at a temperature lower than room temperature. By doing so, the total etching amount can be adjusted to a reduced value.

[0171] In addition, in the substrate processing method according to the embodiment, the first cleaning process (step (S101)) cleans the substrate (wafer (W)) with a first cleaning solution at a temperature lower than room temperature, and the second cleaning process (step (S102)) cleans the substrate (wafer (W)) with a second cleaning solution at a temperature higher than room temperature. By doing so, the total etching amount can be adjusted to a reduced value.

[0172] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible as long as they do not deviate from the spirit thereof. For example, the above embodiments describe cases where an acidic cleaning solution, such as DSP, is used in the cleaning solution, but the cleaning solution according to the embodiments is not limited to an acidic cleaning solution.

[0173] In addition, the above embodiment describes a case where the first cleaning solution and the second cleaning solution are of the same type and have different degrees of cleanliness, but the first cleaning solution and the second cleaning solution may be cleaning solutions that differ in both degree of cleanliness and type.

[0174] The embodiments disclosed herein should be considered as not being limited to examples in all respects. Indeed, the above-described embodiments may be implemented in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and intent of the appended claims.

Claims

Claim 1 A substrate cleaning method for cleaning the surface and back surface of a substrate, comprising: a first cleaning process for cleaning the surface of a substrate with a first cleaning solution; a second cleaning process for cleaning the surface of the substrate with a second cleaning solution having a lower degree of cleanliness than the first cleaning solution after the first cleaning process; and a process for cleaning the surface of the substrate with the first cleaning solution after the second cleaning process, wherein the first cleaning solution is an unused cleaning solution, the second cleaning solution is a cleaning solution recovered after use, the cleaning period using the first cleaning solution is shorter than the cleaning period using the second cleaning solution, and the back surface of the substrate is cleaned with a cleaning solution. Claim 2 A substrate cleaning method according to claim 1, wherein the second cleaning solution is a cleaning solution filtered at a temperature lower than room temperature after use. Claim 3 In claim 2, the first cleaning solution is a cleaning solution that is filtered at a temperature lower than room temperature while unused, in a method for cleaning a substrate. Claim 4 A method for cleaning a substrate according to claim 1, wherein the first cleaning solution is a cleaning solution filtered at a temperature lower than room temperature after use, and the second cleaning solution is a cleaning solution filtered at a temperature higher than room temperature after use. Claim 5 A substrate cleaning method according to any one of claims 1 to 4, further comprising a rinsing process of rinsing the substrate with a functional water after the second cleaning process. Claim 6 A substrate cleaning method according to any one of claims 1 to 4, wherein the first cleaning process cleans the substrate with the first cleaning solution at a temperature higher than room temperature, and the second cleaning process cleans the substrate with the second cleaning solution at a temperature lower than room temperature. Claim 7 A substrate cleaning method according to any one of claims 1 to 4, wherein the first cleaning process cleans the surface of the substrate with the first cleaning solution at a temperature lower than room temperature, and the second cleaning process cleans the surface of the substrate with the second cleaning solution at a temperature higher than room temperature. Claim 8 delete Claim 9 A substrate cleaning device for cleaning the surface and back surface of a substrate, comprising: a substrate processing unit for processing a substrate; a first cleaning liquid supply unit for supplying unused cleaning liquid to the substrate processing unit; a cleaning liquid recovery unit for recovering cleaning liquid that has been used in the substrate processing unit; a second cleaning liquid supply unit for supplying cleaning liquid recovered from the cleaning liquid recovery unit to the substrate processing unit; and a control unit for controlling the substrate processing unit, the first cleaning liquid supply unit, the cleaning liquid recovery unit, and the second cleaning liquid supply unit. The control unit supplies unused cleaning liquid from the first cleaning liquid supply unit to the surface of the substrate, then supplies the recovered cleaning liquid from the second cleaning liquid supply unit to the surface of the substrate, and after supplying the recovered cleaning liquid, supplies unused cleaning liquid from the first cleaning liquid supply unit to the surface of the substrate, and supplies cleaning liquid to the back surface of the substrate, wherein the period for supplying the unused cleaning liquid is shorter than the period for supplying the recovered cleaning liquid. Claim 10 In claim 9, the cleaning solution recovery unit has a filter for filtering the recovered cleaning solution, and the filter is a substrate cleaning device that filters the recovered cleaning solution at a temperature lower than room temperature.

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