JP2024050440A - Lift pin cleaning method and substrate processing apparatus - Google Patents

Abstract

To clean lift pins while suppressing contamination inside an apparatus.
[Solution] A method for cleaning lift pins in a substrate processing apparatus including a rotating plate, multiple support parts, a liquid discharge part, and multiple lift pins, includes a supporting step and a cleaning step. The rotating plate is rotatable. The multiple support parts are provided on the rotating plate and support a substrate. The liquid discharge part discharges a cleaning liquid onto an upper surface of the substrate supported by the multiple support parts. The multiple lift pins push the substrate upward by passing through multiple passing parts provided on the rotating plate. The supporting step supports the substrate using the multiple support parts. The cleaning step discharges a cleaning liquid from the liquid discharge part onto an upper surface of the substrate supported by the multiple support parts with the multiple lift pins positioned lower than the rotating plate, and cleans the multiple lift pins with the cleaning liquid flowing down from the multiple passing parts.
[Selected figure] Figure 2

Description

The disclosed embodiments relate to a lift pin cleaning method and a substrate processing apparatus.

In a conventional substrate processing apparatus having multiple pins for transferring substrates between the substrate processing apparatus and a transport apparatus, a technique is available for removing deposits on each pin by ejecting a cleaning liquid from a cleaning liquid nozzle onto the multiple pins during periods when substrate processing is not being performed (see Patent Document 1).

JP 2017-69261 A

This disclosure provides technology that can clean lift pins while minimizing contamination inside the device.

A method for cleaning lift pins according to one aspect of the present disclosure is a method for cleaning lift pins in a substrate processing apparatus including a rotating plate, multiple support parts, a liquid discharge part, and multiple lift pins, and includes a supporting step and a cleaning step. The rotating plate is rotatable. The multiple support parts are provided on the rotating plate and support a substrate. The liquid discharge part discharges a cleaning liquid onto an upper surface of the substrate supported by the multiple support parts. The multiple lift pins push the substrate upward by passing through multiple passing parts provided on the rotating plate. The supporting step supports the substrate using the multiple support parts. The cleaning step discharges a cleaning liquid from the liquid discharge part onto an upper surface of the substrate supported by the multiple support parts with the multiple lift pins positioned lower than the rotating plate, and cleans the multiple lift pins with the cleaning liquid flowing down from the multiple passing parts.

According to the present disclosure, it is possible to clean the lift pins while minimizing contamination inside the device.

FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the configuration of a processing unit according to the embodiment. FIG. 3 is a diagram illustrating the operation of the gripper and the lift pin according to the embodiment. FIG. 4 is a perspective view of the rotation plate according to the embodiment. FIG. 5 is a plan view of the rotation plate according to the embodiment. FIG. 6 is a flowchart showing a series of processing steps executed by the processing unit according to the embodiment. FIG. 7 is a flowchart showing a procedure of the cleaning process according to the embodiment. FIG. 8 is a diagram showing an example of the operation of the first nozzle in the cleaning process according to the embodiment. FIG. 9 is a diagram showing an example of the operation of the second nozzle in the cleaning process according to the embodiment.

Below, the lift pin cleaning method and substrate processing apparatus according to the present disclosure will be described in detail with reference to the drawings. Note that the lift pin cleaning method and substrate processing apparatus according to the present disclosure are not limited to these embodiments. Furthermore, the embodiments can be appropriately combined as long as they do not cause any contradiction in the processing contents.

There is known a substrate processing apparatus that cleans a substrate by rotating the substrate by placing the substrate on a rotating plate and supplying a cleaning liquid to the upper surface of the substrate from above the rotating substrate.

Such substrate processing apparatus may also include multiple lift pins for transferring the substrate to and from the transport device. The multiple lift pins and the substrate are in direct contact with each other when transferring the substrate to and from the transport device, so there is a risk that particles adhering to the multiple lift pins may adhere to the underside of the substrate. For this reason, it is preferable to periodically clean the multiple lift pins in the substrate processing apparatus.

However, as in the technology described in Patent Document 1, when cleaning liquid is discharged from a cleaning liquid nozzle directly onto multiple lift pins, there is a risk of the cleaning liquid scattering onto the multiple lift pins. If the cleaning liquid scatters onto the multiple lift pins, for example, particles contained in the scattered cleaning liquid may adhere to other components other than the lift pins within the substrate processing apparatus, causing contamination within the substrate processing apparatus.

Therefore, there is a need for technology that can clean the lift pins while minimizing contamination inside the equipment.

<Configuration of Substrate Processing System>
1 is a diagram showing a schematic configuration of a substrate processing system according to an embodiment of the present invention. In the following, in order to clarify the positional relationship, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are defined, and the positive direction of the Z-axis is defined as the vertical upward direction.

As shown in FIG. 1, 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 provided adjacent to each other.

The loading/unloading station 2 includes a carrier placement section 11 and a transport section 12. On the carrier placement section 11, multiple carriers C are placed, each of which horizontally holds multiple substrates, in this embodiment semiconductor wafers (hereafter referred to as wafers W).

The transfer section 12 is provided adjacent to the carrier placement section 11 and includes a substrate transfer device 13 and a transfer section 14. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. The substrate transfer device 13 is capable of moving in the horizontal and vertical directions and rotating about a vertical axis, and transfers the wafer W between the carrier C and the transfer section 14 using the wafer holding mechanism.

The processing station 3 is provided adjacent to the transport section 12. The processing station 3 includes a transport section 15 and a plurality of processing units 16. The plurality of processing units 16 are arranged side by side on both sides of the transport section 15.

The transfer section 15 has a substrate transfer device 17 therein. The substrate transfer device 17 has a wafer holding mechanism that holds the wafer W. The substrate transfer device 17 can move horizontally and vertically and rotate around a vertical axis, and uses the wafer holding mechanism to transfer the wafer W between the delivery section 14 and the processing unit 16.

The processing unit 16 performs a predetermined substrate processing on the wafer W transported by the substrate transport device 17. The processing unit 16 also performs a cleaning process on the lift pins 23H (see Figures 2 and 3) provided in the processing unit 16, which will be described later, using the wafer W transported by the substrate transport device 17.

The substrate processing system 1 also includes a control device 4. The control device 4 is, for example, a computer, and includes a control unit 18 and a memory unit 19. The memory unit 19 stores programs that control the various processes executed 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 memory unit 19.

The program may be recorded on 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 a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 in the loading/unloading station 2 removes the wafer W from the carrier C placed on the carrier placement section 11, and places the removed wafer W on the transfer section 14. The wafer W placed on the transfer section 14 is removed from the transfer section 14 by the substrate transfer device 17 in the processing station 3, and is transferred to the processing unit 16.

The wafer W loaded into the processing unit 16 is processed by the processing unit 16, and then is removed from the processing unit 16 by the substrate transfer device 17 and placed on the transfer section 14. The processed wafer W placed on the transfer section 14 is then returned to the carrier C on the carrier placement section 11 by the substrate transfer device 13.

<Configuration of Processing Unit>
Next, the configuration of the processing unit 16 will be described with reference to Fig. 2. Fig. 2 is a diagram for explaining the configuration of the processing unit 16 according to the embodiment.

As shown in FIG. 2, the processing unit 16 includes a housing 21, a generally cylindrical cup portion 22 that is provided in the center of the housing 21 and has an open top, and a wafer holding and rotating portion 23 that is disposed inside the cup portion 22 and can hold and rotate the wafer W. The processing unit 16 also includes a first supply portion 24 and a second supply portion 25 that supply cleaning liquid to the wafer W held by the wafer holding and rotating portion 23.

The housing 21 is formed with a transfer port (not shown) for transferring the wafer W into and out of the housing 21 by the substrate transfer device 17 (see FIG. 1). The transfer port is provided with a shutter (not shown), which opens during transfer and unloading, and closes during processing to keep the transfer port closed.

The cup portion 22 receives the cleaning liquid supplied to the wafer W and discharges the cleaning liquid through a drain (not shown).

The wafer holding and rotating unit 23 has a rotating shaft 23S that is connected to and rotated by a motor M disposed below the housing 21, and a rotating plate 23P that is attached to the rotating shaft 23S at the center of the bottom surface. The motor M and the rotating shaft 23S are an example of a rotation mechanism that rotates the rotating plate 23P.

The first supply unit 24 moves from the outside of the wafer W to above the wafer W, and supplies the first cleaning liquid, the rinse liquid, and the drying gas toward the upper surface of the wafer W held by the wafer holding and rotating unit 23. The first cleaning liquid is, for example, an alkaline aqueous solution or a mixture of an alkaline aqueous solution and DIW (pure water). The temperature of the first cleaning liquid is lower than 70° C. The alkaline aqueous solution may be, for example, an inorganic alkaline aqueous solution or an organic alkaline aqueous solution. The inorganic alkaline aqueous solution is, for example, an SC1 solution (a mixture of ammonia and hydrogen peroxide). The organic alkaline aqueous solution is, for example, a solution containing at least one of TMAH (tetramethylammonium hydroxide) and a choline aqueous solution. The rinse liquid is, for example, DIW. The drying gas is, for example, N2 gas.

The first supply unit 24 includes a first arm 24a that supports the first nozzle 24A, the rinse nozzle 24B, and the drying nozzle 24C, and a pivoting and lifting mechanism 24b that pivots the first arm 24a in the horizontal direction and raises and lowers it in the vertical direction. Although not shown, the first supply unit 24 may also include a movement mechanism that moves the first arm 24a in the horizontal direction.

The first nozzle 24A is connected to a chemical liquid supply source 31 via a flow rate adjustment mechanism 26a such as a valve. The chemical liquid supply source 31 is, for example, a tank, and stores a chemical liquid such as an alkaline aqueous solution or a mixture of an alkaline aqueous solution and DIW (pure water) as a first cleaning liquid. The first nozzle 24A ejects the first cleaning liquid onto the upper surface of the wafer W. The first nozzle 24A is an example of a first liquid ejection unit.

The rinse nozzle 24B is connected to a DIW supply source 32 via a flow rate adjustment mechanism 26b such as a valve. The DIW supply source 32 is, for example, a tank, and stores DIW as a rinse liquid. The rinse nozzle 24B ejects the rinse liquid onto the top surface of the wafer W.

The drying nozzle 24C is connected to an N2 gas supply source 33 via a flow rate adjustment mechanism 26c such as a valve. The N2 gas supply source 33 is, for example, a tank that stores N2 gas. The drying nozzle 24C ejects N2 gas, which is a drying gas, onto the upper surface of the wafer W.

The second supply unit 25 moves from the outside of the wafer W to above the wafer W, and supplies the second cleaning liquid toward the upper surface of the wafer W held by the wafer holding and rotating unit 23. The second cleaning liquid is a mixed fluid of liquid and gas. As the liquid, a solution obtained by dissolving at least one of CO2 gas, ammonia gas, and ammonia water in DIW can be used, and such a liquid is also called functional water. When the liquid as functional water is a solution obtained by dissolving CO2 gas in DIW, the resistivity of the liquid is preferably smaller than 0.1 (MΩ·cm). Also, when the liquid as functional water is a solution obtained by dissolving at least one of ammonia gas and ammonia water in DIW, the concentration of ammonia in the liquid is preferably 1 (ppm) or more and 100 (ppm) or less. By using functional water as the liquid contained in the mixed fluid that is the second cleaning liquid, the wafer W is de-electrified, and damage (electrostatic destruction) that the wafer W receives when the second cleaning liquid comes into contact with the wafer W is suppressed. As the gas, N2 gas can be used.

The second supply unit 25 includes a second arm 25a that supports the second nozzle 25A, and a pivoting and lifting mechanism 25b that pivots the second arm 25a in the horizontal direction and raises and lowers it in the vertical direction. Although not shown, the second supply unit 25 may also include a movement mechanism that moves the second arm 25a in the horizontal direction.

A functional water supply source 34 is connected to the second nozzle 25A via a flow rate adjustment mechanism 26d such as a valve. The functional water supply source 34 is, for example, a tank, and stores functional water. In addition, an N2 gas supply source 33 is connected to the second nozzle 25A via a flow rate adjustment mechanism 26e such as a valve. The second nozzle 25A is, for example, a two-fluid nozzle, and mixes the functional water and N2 gas inside to generate a mixed fluid that is a second cleaning liquid, and ejects the second cleaning liquid onto the upper surface of the wafer W. The pressure of the N2 gas supplied to the second nozzle 25A is relatively high, and the second nozzle 25A can attract the high-pressure mixed fluid to the upper surface of the wafer W. The second nozzle 25A is an example of a second liquid ejection unit.

The rotating shaft 23S has a conduit 23C formed therethrough that passes through its center. The conduit 23C is connected to the N2 gas supply source 33 via a flow rate adjustment mechanism 26f such as a valve. A space is formed between the rotating plate 23P of the wafer holding and rotating unit 23 and the wafer W held by the wafer holding and rotating unit 23, and the N2 gas that passes through the conduit 23C flows out of the upper end of the conduit 23C into this space and flows toward the outer periphery. When the wafer holding and rotating unit 23 and the wafer W rotate, the space between the rotating plate 23P and the wafer W becomes more negatively pressurized than the space above the wafer W. This may cause the center of the wafer W to bend, deteriorating the flatness of the upper surface of the wafer W and deteriorating the uniformity of the liquid processing. However, since N2 gas is supplied to the space, it is possible to suppress the bending of the center of the wafer W. In addition, since N2 gas is blown out from the space between the rotating plate 23P and the wafer W, the effect of reducing adhesion of the processing liquid supplied to the upper surface of the wafer W to the lower surface is obtained.

The gas supplied from conduit 23C is not limited to N2 gas, but may be other inert gases such as argon gas or dry air.

The rotating plate 23P is a disk-shaped member that can be rotated by a motor M and a rotating shaft 23S. The peripheral portion of the rotating plate 23P is provided with a plurality of gripping portions 23G (only one is shown in FIG. 2) that grip the wafer W from the side by pressing against the peripheral portion of the wafer W.

Each gripping portion 23G has a lever member 23L that can rotate around a rotation axis 23T, and a gripping piece 23A that can rotate with the rotation of the lever member 23L to contact the peripheral portion of the wafer W. Below each lever member 23L, a push-up plate 41 that can abut against one end of the lever member 23L is provided. The push-up plate 41 extends horizontally and is supported from below by a plurality of support members 42 that extend vertically. The plurality of support members 42 are supported from below by arm members 43 that extend horizontally, and the arm members 43 move up and down by a lifting mechanism 44.

In addition, below the rotating plate 23P, there are provided a plurality of lift pins 23H (only one is shown in FIG. 2) that support the peripheral portion of the wafer W from below and move the wafer W up and down when transferring the wafer W to and from the substrate transfer device 17 (see FIG. 1). Each lift pin 23H extends vertically and is supported by an arm member 51 that extends horizontally. The arm member 51 moves up and down by a lifting mechanism 52.

Here, the operation of the gripper 23G and lift pin 23H described above will be described with reference to FIG. 3. FIG. 3 is an explanatory diagram of the operation of the gripper 23G and lift pin 23H according to the embodiment.

As shown in FIG. 3, when the wafer W is loaded, the push-up plate 41 is moved upward by the lifting mechanism 44, and pushes up one end of the lever member 23L of the gripping portion 23G. As a result, the gripping piece 23A provided at the other end of the lever member 23L is tilted outward.

When the wafer W is loaded, the lift pins 23H are moved upward by the lifting mechanism 52 and are positioned higher than the rotating plate 23P.

A passage 65 is formed on the outer periphery of the rotating plate 23P to allow the lift pins 23H to pass through. The passage 65 is a cutout formed by cutting the outer periphery of the rotating plate 23P radially inward. A plurality of passages 65 are provided for the rotating plate 23P, but only one passage 65 is shown in Figures 2 and 3.

When the wafer W is loaded, the lift pins 23H are raised by the lifting mechanism 52, pass through the passage 65 provided on the rotating plate 23P, and are positioned at a higher position than the rotating plate 23P.

The wafer W loaded into the housing 21 is transferred from the substrate transfer device 17 to the multiple lift pins 23H. After that, when the multiple lift pins 23H descend to a position lower than the rotating plate 23P, the push-up plate 41 descends. This releases the contact between the push-up plate 41 and the lever member 23L, and the lever member 23L rotates about the rotating shaft 23T, with the gripping piece 23A being pressed against the peripheral portion of the wafer W. The gripping pieces 23A of the multiple gripping parts 23G press against the peripheral portion of the wafer W, gripping the wafer W. In this state, when the motor M rotates, the rotating plate 23P and the gripping parts 23G attached thereto rotate, and the wafer W gripped by the gripping parts 23G rotates on the rotating plate 23P.

When the wafer W is unloaded, the multiple gripping parts 23G release the grip of the wafer W, and the lift pins 23H are raised by the lifting mechanism 52, pass through the passage parts 65 provided on the rotating plate 23P, and contact the wafer W from below. The lift pins 23H then push the wafer W upward. The wafer W pushed up by the lift pins 23H is transferred to the substrate transfer device 17, and is unloaded from the housing 21 by the substrate transfer device 17.

<Configuration of Rotating Plate>
Next, the configuration of the rotating plate 23P will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a perspective view of the rotating plate 23P according to the embodiment, and Fig. 5 is a plan view of the rotating plate 23P according to the embodiment.

As shown in Figures 4 and 5, the rotating plate 23P has a first flat portion 61, an inclined portion 62, and a second flat portion 63.

The first flat portion 61 has a disk shape with a smaller diameter than the wafer W. An opening 61a is provided in the center of the first flat portion 61 for supplying N2 gas to the underside of the wafer W.

The inclined portion 62 is disposed adjacent to the outer periphery of the first flat portion 61. The inclined portion 62 has a diameter larger than the wafer W and has an inclined surface that slopes downward from the outside of the wafer W (the second flat portion 63) toward the inside of the wafer W (the first flat portion 61). Such an inclined surface extends along the circumferential direction of the wafer W. Specifically, the inclined surface of the inclined portion 62 is provided around the entire outer periphery of the first flat portion 61. The second flat portion 63 has a flat surface that is adjacent to the outer periphery of the inclined portion 62.

The rotating plate 23P is also provided with a number of cutouts 64, a number of passages 65, a number of support portions 66, and a number of raised portions 67.

The multiple cutouts 64 are cutouts formed by cutting out the outer periphery of the rotating plate 23P inward in the radial direction at the portions corresponding to the multiple gripping pieces 23A. The cutouts 64 reach the middle of the inclined surface of the inclined portion 62. The gripping pieces 23A of the gripping portion 23G are positioned in the cutouts 64.

The multiple passing portions 65 are notches cut radially inward from the portions of the outer periphery of the rotating plate 23P that correspond to the multiple lift pins 23H. The multiple passing portions 65 may be through holes that vertically pass through the portions of the outer periphery of the rotating plate 23P that correspond to the multiple lift pins 23H. The passing portions 65 are larger than the notches 64 and reach the bottom of the inclined surface of the inclined portion 62. The lift pins 23H move up and down through these passing portions 65.

In this embodiment, an example is shown in which three notches 64 and three passages 65 are arranged alternately at a predetermined interval on the outer periphery of the rotating plate 23P, but the number and arrangement of the multiple notches 64 and passages 65 are not limited to the above example.

The multiple support parts 66 are provided so as to protrude from the inclined surface of the inclined part 62, and support the wafer W from below. The support parts 66 have an elongated shape that extends from the outside to the inside of the wafer W, specifically, along the radial direction of the first flat part 61 (in other words, the wafer W).

In addition, a raised portion 67 is provided radially inward of the passing portion 65 on the rotating plate 23P, which raises the inclined surface of the inclined portion 62 and a part of the first flat portion 61.

The raised portion 67 is connected to the passing portion 65 and two support portions 66 provided on either side of the passing portion 65.

<Specific Operation of Processing Unit>
Next, a specific operation of the processing unit 16 according to the embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing a series of processing steps executed by the processing unit 16 according to the embodiment. Each processing step shown in Fig. 6 is executed under the control of the control unit 18.

In the following, the wafer W is assumed to be a dummy wafer (an example of a dummy substrate) that is different from the wafer to be processed (an example of a product substrate). When the wafer W is a dummy wafer, the series of processing steps shown in FIG. 6 is performed during a period when the processing unit 16 is not performing substrate processing on the wafer to be processed. In the following, the circuit-forming surface of the wafer W is referred to as the "main surface" and the surface opposite the main surface is referred to as the "rear surface."

As shown in FIG. 6, in the processing unit 16, first, a loading process is performed (step S101). In the loading process, the wafer W is loaded into the housing 21 of the processing unit 16 by the substrate transfer device 17 (see FIG. 1). Note that the wafer W is loaded with its main surface facing downward. The wafer W loaded into the housing 21 is supported by the multiple support parts 66 of the rotating plate 23P and gripped by the multiple gripping parts 23G. At this time, the multiple lift pins 23H are positioned lower than the rotating plate 23P (as shown in FIG. 2).

Next, in the processing unit 16, a cleaning process is performed (step S102). In the cleaning process, with the lift pins 23H positioned lower than the rotating plate 23P, a cleaning liquid is discharged from the first nozzle 24A and the second nozzle 25A onto the upper surface of the wafer W, and the lift pins 23H are cleaned by the cleaning liquid flowing down from the passages 65.

The multiple lift pins 23H and the wafer W come into direct contact with each other when the wafer W is transferred between the processing unit 16 and the substrate transfer device 17. This may cause, for example, particles adhering to the multiple lift pins 23H to adhere to the lower surface (main surface) of the wafer W. For this reason, in order to prevent particle adhesion, it is preferable to periodically clean the multiple lift pins 23H.

In this regard, it is possible to eject cleaning liquid directly from a cleaning liquid nozzle onto multiple lift pins 23H, as in the conventional technology.

However, when cleaning liquid is discharged from the cleaning liquid nozzle directly onto the multiple lift pins 23H, there is a risk that the cleaning liquid will splash onto the multiple lift pins 23H. If the cleaning liquid splashes onto the multiple lift pins 23H, for example, particles contained in the splashed cleaning liquid may adhere to other parts, etc., other than the lift pins 23H within the processing unit 16, causing contamination within the processing unit 16.

The processing unit 16 according to the embodiment performs a cleaning process in which a cleaning liquid is discharged onto the upper surface of the wafer W while the lift pins 23H are positioned at a lower position than the rotating plate 23P, and the cleaning liquid flows down from the passages 65 to clean the lift pins 23H.

This cleaning process can reduce the area over which the cleaning liquid is scattered from the multiple lift pins 23H, compared to conventional technology in which the cleaning liquid is directly ejected from a cleaning liquid nozzle onto the multiple lift pins 23H. As a result, the lift pins 23H can be cleaned while minimizing contamination inside the processing unit 16.

The above-mentioned cleaning process will be described in more detail with reference to Figs. 7 to 9. Fig. 7 is a flowchart showing the procedure of the cleaning process according to the embodiment. Fig. 8 is a diagram showing an example of the operation of the first nozzle 24A in the cleaning process according to the embodiment. Fig. 9 is a diagram showing an example of the operation of the second nozzle 25A in the cleaning process according to the embodiment.

As shown in FIG. 7, when the wafer W is supported by the multiple supports 66 of the rotating plate 23P and gripped by the multiple grippers 23G, the processing unit 16 starts rotating the wafer W (step S201). The wafer W is rotated by rotating the rotating shaft 23S and the rotating plate 23P using the motor M. The rotation of the wafer W continues until the series of processing steps shown in FIG. 6 is completed.

Next, the processing unit 16 uses the swivel lift mechanism 24b to position the first nozzle 24A above the wafer W (step S202).

Next, the processing unit 16 starts discharging the first cleaning liquid L1 from the first nozzle 24A onto the upper surface of the rotating wafer W (step S203). As shown in FIG. 8, the first cleaning liquid L1 discharged onto the upper surface of the wafer W is spread on the upper surface of the wafer W by the centrifugal force accompanying the rotation of the wafer W, and splashes outward from the peripheral portion of the wafer W. In addition, a part of the first cleaning liquid L1 discharged onto the upper surface of the wafer W flows around the peripheral portion of the wafer W from the upper surface to the lower surface of the wafer W, and splashes from the lower surface of the wafer W toward the passing portion 65 of the rotating plate 23P. The first cleaning liquid L1 splashed toward the passing portion 65 flows down from the passing portion 65 of the rotating plate 23P and lands on the lift pins 23H. As a result, foreign matter such as particles attached to the lift pins 23H is washed away by the first cleaning liquid L1.

The first cleaning liquid L1 is a chemical liquid such as an alkaline aqueous solution or a mixture of an alkaline aqueous solution and pure water, and therefore has a chemical reactivity capable of removing foreign matter such as particles adhering to the lift pins 23H. By cleaning the lift pins 23H with the first cleaning liquid L1, the efficiency of removing foreign matter such as particles adhering to the lift pins 23H can be improved.

The processing unit 16 continues to eject the first cleaning liquid L1 for a predetermined time. After that, the processing unit 16 stops ejecting the first cleaning liquid L1 (step S204).

The processes in steps S201 to S204 are an example of a first cleaning process in which the first cleaning liquid is ejected from the first nozzle 24A onto the top surface of the substrate while rotating the substrate supported by the multiple supports 66 using the rotating plate 23P.

Next, the processing unit 16 uses the swivel lift mechanism 25b to position the second nozzle 25A above the center of the wafer W (step S205).

Next, the processing unit 16 starts to eject the second cleaning liquid L2 from the second nozzle 25A onto the top surface of the rotating wafer W (step S206).

Next, the processing unit 16 uses the swivel lift mechanism 25b to move the second nozzle 25A from the center to the periphery of the wafer W while discharging the second cleaning liquid L2 from the second nozzle 25A (step S207). The second cleaning liquid L2 discharged onto the upper surface of the wafer W scatters outward from the periphery of the wafer W, as shown in FIG. 9. A part of the second cleaning liquid L2 discharged onto the upper surface of the wafer W flows from the upper surface to the lower surface of the wafer W at the periphery of the wafer W, and scatters from the lower surface of the wafer W toward the passing portion 65 of the rotating plate 23P. The second cleaning liquid L2 that has scattered toward the passing portion 65 flows down from the passing portion 65 of the rotating plate 23P and lands on the lift pins 23H. As a result, foreign matter such as particles that have not been washed away from the lift pins 23H by the first cleaning liquid L1 is washed away by the second cleaning liquid L2.

The second cleaning liquid L2 is a mixed fluid of functional water and N2 gas, which has a relatively high pressure, and therefore adheres to foreign matter such as particles adhering to the lift pins 23H at high pressure. By cleaning the lift pins 23H with the second cleaning liquid L2, the efficiency of removing foreign matter such as particles adhering to the lift pins 23H can be improved.

Here, if the second nozzle 25A is moved at a constant speed in the process of step S207, the processing time of the cleaning process may become longer than necessary. In addition, if the amount of the second cleaning liquid L2 remaining on the upper surface of the wafer W is insufficient, the amount of the second cleaning liquid L2 splashing toward the passing section 65 may also be insufficient.

The processing unit 16 may control the swivel lift mechanism 25b to increase the moving speed of the second nozzle 25A as the second nozzle 25A moves from the center of the wafer W to a predetermined position where the second nozzle 25A does not reach the peripheral edge of the wafer W. Furthermore, the processing unit 16 may decrease the moving speed of the second nozzle 25A as the second nozzle 25A moves from the predetermined position to the peripheral edge of the wafer W. This makes it possible to shorten the processing time of the cleaning process while maintaining the amount of the second cleaning liquid L2 that splashes toward the passing section 65.

The processes in steps S205 to S207 are an example of a second cleaning process in which the second nozzle 25A is moved from the center to the periphery of the substrate while rotating the substrate, and the second cleaning liquid L2 is ejected from the second nozzle 25A onto the upper surface of the substrate.

When the second nozzle 25A reaches the peripheral portion of the wafer W, the processing unit 16 determines whether the movement of the second nozzle 25A has been repeated a predetermined number of times (step S208). If the movement of the second nozzle 25A has not been repeated a predetermined number of times (step S208; No), the processing unit 16 returns the process to step S205 and repeats the processes of steps S205 to S207. That is, the processing unit 16 repeats the second cleaning process (processes of steps S205 to S207) multiple times after the first cleaning process (processes of steps S201 to S204). This allows the processing unit 16 to further improve the efficiency of removing foreign matter such as particles adhering to the lift pins 23H.

On the other hand, if the movement of the second nozzle 25A has been repeated a predetermined number of times (step S208; Yes), the processing unit 16 stops discharging the second cleaning liquid L2 (step S209) and ends the cleaning process.

In the above-mentioned cleaning process example, both the first cleaning step (steps S201 to S204) and the second cleaning step (steps S205 to S207) were performed, but only one of the first cleaning step and the second cleaning step may be performed. This simplifies the process. Depending on the specifications of the processing unit 16, the use of the first cleaning liquid L1, which is a chemically reactive chemical liquid, may not be appropriate. In such a case, the processing unit 16 can satisfy the specifications of the processing unit 16 that are not suitable for the use of chemical liquids by performing only the second cleaning step using the second cleaning liquid L2, which is a mixed fluid of functional water and N2 gas.

In addition, in the process of step S207, after the second nozzle 25A reaches the peripheral portion of the wafer W, the second nozzle 25A may be stopped at the peripheral portion of the wafer W for a predetermined time while continuing to eject the second cleaning liquid L2 from the second nozzle 25A. This increases the amount of the second cleaning liquid L2 that flows down from the passage portion 65 of the rotating plate 23P toward the lift pins 23H at the peripheral portion of the wafer W, thereby further improving the cleaning efficiency of the lift pins 23H.

After the cleaning process in step S102 (see FIG. 6) is completed, the processing unit 16 performs a rinse process (step S103). In the rinse process, the processing unit 16 ejects DIW, which is a rinse liquid, onto the center of the upper surface of the wafer W from the rinse nozzle 24B disposed above the wafer W. The DIW ejected onto the center of the wafer W spreads from the center to the periphery of the wafer W due to centrifugal force, and the cleaning liquid remaining on the upper surface of the wafer W is washed away by the DIW. In the rinse process, the cleaning liquid remaining on the surfaces of the multiple lift pins 23H is also washed away by the DIW flowing down from the multiple passages 65 of the rotating plate 23P.

Next, in the processing unit 16, a drying process is performed (step S104). In the drying process, the processing unit 16 increases the rotation speed of the wafer W. Then, while rotating the wafer W, the processing unit 16 ejects N2 gas from the drying nozzle 24C onto the upper surface of the wafer W. As a result, the liquid remaining on the main surface of the wafer W is shaken off by centrifugal force and pushed toward the peripheral portion of the wafer W by the N2 gas, thereby drying the wafer W.

Next, in the processing unit 16, an unloading process is performed (step S105). In the unloading process, the wafer W is unloaded from the housing 21 by the substrate transfer device 17 (see FIG. 1). The wafer W unloaded from the housing 21 is stored in the carrier C by the substrate transfer device 17.

As described above, the substrate processing apparatus (e.g., processing unit 16) according to the embodiment includes a rotating plate (e.g., rotating plate 23P), a plurality of support parts (e.g., support part 66), a liquid discharge part (e.g., first nozzle 24A and second nozzle 25A), and a plurality of lift pins (e.g., lift pins 23H). The rotating plate is rotatable. The plurality of support parts are provided on the rotating plate and support a substrate (e.g., wafer W). The liquid discharge part discharges a cleaning liquid (e.g., first cleaning liquid and second cleaning liquid) onto the upper surface of the substrate supported by the plurality of support parts. The plurality of lift pins push the substrate upward by passing through a plurality of passing parts (e.g., passing part 65) provided on the rotating plate. The method for cleaning the lift pins according to the embodiment performed in such a substrate processing apparatus includes a supporting process and a cleaning process. The supporting process supports the substrate using the plurality of supporting parts. In the cleaning process, with the lift pins positioned lower than the rotating plate, a cleaning liquid is discharged from the liquid discharger onto the top surface of the substrate supported by the support parts, and the lift pins are cleaned by the cleaning liquid flowing down from the passage parts. In this way, the substrate processing apparatus according to the embodiment can clean the lift pins while suppressing contamination inside the apparatus.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. Indeed, the above-described embodiments may be embodied in various forms. Furthermore, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

REFERENCE SIGNS LIST 1 Substrate processing system 4 Control device 16 Processing unit 18 Control unit 19 Memory unit 23 Wafer holding and rotating unit 23P Rotation plate 24 First supply unit 24A First nozzle 25 Second supply unit 25A Second nozzle 65 Passing unit 66 Support unit W Wafer

Claims (16)

A rotatable rotating plate;
a plurality of supports provided on the rotating plate for supporting a substrate;
a liquid discharge unit that discharges a cleaning liquid onto an upper surface of the substrate supported by the plurality of supports;
a plurality of lift pins that push up the substrate by passing through a plurality of passing portions provided on the rotating plate, respectively,
a supporting step of supporting the substrate using the plurality of supports;
and a cleaning process of discharging the cleaning liquid from the liquid discharge section onto an upper surface of the substrate supported by the plurality of support sections while the plurality of lift pins are positioned at a position lower than the rotating plate, and cleaning the plurality of lift pins with the cleaning liquid flowing down from the plurality of passing sections. The substrate processing apparatus includes a plurality of the liquid discharge units,
The liquid discharge units include
a first liquid ejection unit that ejects a first cleaning liquid onto an upper surface of the substrate supported by the plurality of supports;
a second liquid ejection unit that ejects a second cleaning liquid onto an upper surface of the substrate supported by the plurality of supports,
The washing step comprises:
a first cleaning step of discharging the first cleaning liquid from the first liquid discharger onto an upper surface of the substrate while rotating the substrate supported by the plurality of supports using the rotation plate;
2. The lift pin cleaning method according to claim 1, further comprising: a second cleaning step of, after the first cleaning step, rotating the substrate and moving the second liquid discharger from a central portion side to a peripheral portion side of the substrate while discharging the second cleaning liquid from the second liquid discharger onto an upper surface of the substrate. The washing step comprises:
The lift pin cleaning method according to claim 2 , wherein the second cleaning step is repeated a plurality of times after the first cleaning step. The second cleaning step includes:
3. The lift pin cleaning method according to claim 2, wherein a moving speed of the second liquid discharging part is increased as the second liquid discharging part approaches from a center of the substrate to a predetermined position not reaching the peripheral edge of the substrate, and a moving speed of the second liquid discharging part is decreased as the second liquid discharging part approaches from the predetermined position to the peripheral edge of the substrate. The lift pin cleaning method according to claim 2, wherein the first cleaning liquid is an alkaline aqueous solution or a mixture of an alkaline aqueous solution and pure water. The lift pin cleaning method according to claim 5, wherein the alkaline aqueous solution is an inorganic alkaline aqueous solution or an organic alkaline aqueous solution. The inorganic alkaline aqueous solution is a mixture of ammonia and hydrogen peroxide,
7. The lift pin cleaning method according to claim 6, wherein the organic alkaline aqueous solution is a solution containing at least one of TMAH (tetramethylammonium hydroxide) and a choline aqueous solution. The lift pin cleaning method according to claim 2, wherein the second cleaning liquid is a mixed fluid of liquid and gas. The lift pin cleaning method according to claim 8, wherein the liquid is a solution obtained by dissolving at least one of CO2 gas, ammonia gas, and ammonia water in pure water. The lift pin cleaning method according to claim 8, wherein the gas is N2 gas. The washing step comprises:
2. The lift pin cleaning method according to claim 1, further comprising the steps of: rotating the substrate supported by the plurality of supports using the rotating plate; and discharging the cleaning liquid from the liquid discharger onto the upper surface of the substrate while moving the liquid discharger from a central portion side to a peripheral portion side of the substrate. The lift pin cleaning method according to claim 11, wherein the cleaning liquid is a mixed fluid of liquid and gas. The washing step comprises:
2. The lift pin cleaning method according to claim 1, wherein the cleaning liquid is discharged from the liquid discharge portion onto an upper surface of the substrate while the substrate supported by the plurality of supports is rotated using the rotating plate. The method for cleaning lift pins according to claim 13, wherein the cleaning liquid is an alkaline aqueous solution or a mixture of an alkaline aqueous solution and pure water. The substrate is a dummy substrate different from a product substrate,
2. The lift pin cleaning method according to claim 1, wherein the supporting step and the cleaning step are performed during a period when the product substrate is not being processed by the substrate processing apparatus. A rotatable rotating plate;
a plurality of supports provided on the rotating plate for supporting a substrate;
a liquid discharge unit that discharges a cleaning liquid onto an upper surface of the substrate supported by the plurality of supports;
a plurality of lift pins that push the substrate upward by passing through a plurality of passages provided on the rotating plate;
A control unit for controlling each unit,
The control unit is
Supporting the substrate using the plurality of supports;
the cleaning liquid is discharged onto an upper surface of the substrate from the liquid discharge part while the plurality of lift pins are disposed at a position lower than the rotation plate, and the plurality of lift pins are cleaned by the cleaning liquid flowing down from the plurality of passage parts.
Substrate processing equipment.

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