JP7769735B2 - Foreign matter detection device, substrate processing apparatus, foreign matter detection method, and storage medium - Google Patents

Description

This disclosure relates to a foreign matter detection device, a substrate processing device, a foreign matter detection method, and a storage medium.

Patent Document 1 discloses a device for detecting submicron particles present as insoluble matter in a fluid. This detection device is composed of an optical system that focuses light from a coherent light source, a cell that is placed near the focus of the light beam focused by this optical system and through which a flow of fluid containing fine particles passes, a photodetector that is placed in the optical path of the light beam and on the opposite side of the cell from the light source of the light beam, and an electrical circuit that measures the number of fine particles in the fluid from the electrical signal from the photodetector.

Japanese Patent Application Publication No. 5-215664

This disclosure provides a foreign matter detection device, substrate processing apparatus, foreign matter detection method, and storage medium that can confirm whether the condition of the device or processing liquid is normal.

According to one exemplary embodiment, a foreign matter detection device includes a detection unit having a flow path forming unit that forms a processing liquid flow path through which processing liquid supplied to a substrate flows, and a measurement unit configured to receive emitted light from the processing liquid flow path when light from a light source is irradiated onto the processing liquid flow path; a foreign matter determination unit that determines whether foreign matter is contained in the processing liquid based on the signal intensity of the emitted light; and an intensity information acquisition unit that acquires intensity information indicating the intensity of background light contained in the emitted light based on the signal intensity.

This disclosure provides a foreign matter detection device, substrate processing apparatus, foreign matter detection method, and storage medium that can confirm whether the condition of the device or processing liquid is normal.

FIG. 1 is a schematic perspective view showing an example of a substrate processing system. FIG. 2 is a schematic diagram showing an example of a coating and developing apparatus. FIG. 3 is a schematic diagram showing an example of the liquid processing unit. FIG. 4 is a schematic diagram illustrating an example of a processing liquid supply section of the liquid processing unit. FIG. 5 is a side view schematically illustrating an example of a foreign object detection unit. FIG. 6 is a perspective view schematically illustrating an example of a foreign object detection unit. FIG. 7 is a side view schematically illustrating an example of a foreign object detection unit. FIG. 8 is a block diagram showing an example of the functional configuration of the control unit. FIG. 9 is a graph showing an example of signal intensity according to detected light. FIG. 10 is a block diagram illustrating an example of a hardware configuration of the control unit. FIG. 11 is a flowchart showing an example of a foreign object detection method.

Various exemplary embodiments are described below.

According to one exemplary embodiment, a foreign matter detection device includes a detection unit having a flow path forming unit that forms a processing liquid flow path through which processing liquid supplied to a substrate flows, and a measurement unit configured to receive emitted light from the processing liquid flow path when light from a light source is irradiated onto the processing liquid flow path; a foreign matter determination unit that determines whether foreign matter is contained in the processing liquid based on the signal intensity of the emitted light; and an intensity information acquisition unit that acquires intensity information indicating the intensity of background light contained in the emitted light based on the signal intensity.

In addition to detecting foreign objects based on the emitted light from the processing liquid flow path when irradiated with irradiation light, this foreign object detection device also acquires intensity information about the background light contained in the emitted light. Because the intensity information changes based on the state of the detection unit or processing liquid, the foreign object detection device makes it possible to confirm whether the state of the device or processing liquid is normal.

The emitted light may be light that is scattered within the treatment liquid flow path when the irradiation light is emitted. In this case, the difference in the intensity of the detection light depending on whether or not a foreign object is present in the treatment liquid is large, making it possible to more reliably detect foreign objects.

The intensity information acquisition unit may acquire the time average of the signal intensity obtained over a predetermined period as the intensity information. Because the intensity of the background light can vary depending on the time of acquisition, basing it on the time average makes it possible to more reliably check the status of the device or processing liquid.

The foreign matter determination unit may determine whether foreign matter is present in the processing liquid during the supply period from the start to the end of supply of the processing liquid to the substrate. The intensity information acquisition unit may acquire intensity information based on the signal intensity obtained during the supply period. In this case, the information obtained during the supply period can be used to efficiently check the status of the processing liquid or the detection unit.

The intensity information acquisition unit may acquire intensity information based on the signal intensity obtained when the processing liquid flow path is filled with processing liquid and no processing liquid is being supplied to the substrate. In this case, disturbance components that may be included in the background light due to the flow of processing liquid can be reduced, allowing for more accurate confirmation of the state of the device or processing liquid.

The foreign matter detection device may further include a status monitoring unit that monitors the status of at least one of the processing liquid and the detection unit based on the intensity information. In this case, it is possible to detect foreign matter after checking the status of the device or processing liquid.

A substrate processing apparatus according to one exemplary embodiment includes a processing liquid supply unit having a nozzle that ejects processing liquid toward a substrate and a supply unit that supplies processing liquid to the nozzle; a flow path forming unit that forms a processing liquid flow path through which the processing liquid flows; a detection unit having a measurement unit configured to receive output light emitted from the processing liquid flow path when light from a light source is irradiated onto the processing liquid flow path; a foreign matter determination unit that determines whether the processing liquid contains foreign matter based on the signal intensity of the output light; and an intensity information acquisition unit that acquires intensity information indicating the intensity of background light contained in the output light based on the signal intensity. Similar to the foreign matter detection device described above, this substrate processing apparatus makes it possible to check whether the apparatus or processing liquid is in a normal state.

A foreign matter detection method according to one exemplary embodiment includes: determining whether foreign matter is present in the processing liquid based on the signal intensity of light emitted from the processing liquid flow path when light from a light source is irradiated onto the processing liquid flow path through which the processing liquid supplied to the substrate flows; and acquiring intensity information indicating the intensity of background light contained in the emitted light based on the signal intensity. Similar to the foreign matter detection device described above, this foreign matter detection method makes it possible to confirm whether the device or processing liquid is in a normal state.

In one exemplary embodiment, a computer-readable storage medium stores a program for causing an apparatus to execute the foreign object detection method described above.

One embodiment will now be described with reference to the drawings. In the description, identical elements or elements with identical functions will be given the same reference numerals, and duplicate explanations will be omitted. Some drawings show a Cartesian coordinate system defined by the X, Y, and Z axes. In the following embodiment, the Z axis corresponds to the vertical direction, and the X and Y axes correspond to the horizontal direction.

[Substrate processing system]
The substrate processing system 1 (substrate processing apparatus) shown in FIG. 1 is a system that forms a photosensitive coating on a workpiece W, exposes the photosensitive coating, and develops the photosensitive coating. The workpiece W to be processed is, for example, a substrate, or a substrate on which a film, circuit, or the like has been formed by undergoing a predetermined process. One example of a substrate included in the workpiece W is a wafer containing silicon. The workpiece W (substrate) may be formed in a circular shape. The workpiece W to be processed may be a glass substrate, a mask substrate, an FPD (Flat Panel Display), or the like, or may be an intermediate product obtained by undergoing a predetermined process on such a substrate. The photosensitive coating is, for example, a resist film.

The substrate processing system 1 includes a coating/developing apparatus 2 and an exposure apparatus 3. The exposure apparatus 3 exposes a resist film (photosensitive coating) formed on a workpiece W (substrate). Specifically, the exposure apparatus 3 irradiates the exposure target portion of the resist film with energy rays using a method such as immersion exposure. The coating/developing apparatus 2 applies resist (chemical liquid) to the surface of the workpiece W to form a resist film before the exposure process by the exposure apparatus 3, and then develops the resist film after the exposure process.

(Substrate processing apparatus)
1 and 2 , the coating and developing apparatus 2 includes a carrier block 4, a processing block 5, an interface block 6, and a control device 18.

The carrier block 4 introduces and removes workpieces W into and from the coating and developing device 2. For example, the carrier block 4 can support multiple carriers C for the workpieces W and incorporates a transport device A1 including a transfer arm. The carrier C accommodates, for example, multiple circular workpieces W. The transport device A1 removes the workpieces W from the carrier C and passes them to the processing block 5, and receives the workpieces W from the processing block 5 and returns them to the carrier C. The processing block 5 has multiple processing modules 11, 12, 13, and 14.

The processing module 11 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 11 forms an underlayer film on the surface of the workpiece W using the liquid processing unit U1 and the heat processing unit U2. The liquid processing unit U1 applies a processing liquid for forming the underlayer film onto the workpiece W. The heat processing unit U2 performs various heat treatments associated with the formation of the underlayer film.

The processing module 12 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 12 forms a resist film on the underlying film using the liquid processing unit U1 and heat processing unit U2. The liquid processing unit U1 applies a processing liquid (resist) for forming the resist film onto the underlying film. The heat processing unit U2 performs various heat treatments associated with the formation of the resist film.

The processing module 13 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 13 forms an upper layer film on the resist film using the liquid processing unit U1 and heat processing unit U2. The liquid processing unit U1 applies a processing liquid for forming the upper layer film onto the resist film. The heat processing unit U2 performs various heat treatments associated with the formation of the upper layer film.

The processing module 14 incorporates a liquid processing unit U1, a heat processing unit U2, and a transport device A3 that transports the workpiece W to these units. The processing module 14 uses the liquid processing unit U1 and heat processing unit U2 to perform development processing of the exposed resist film and heat processing associated with the development processing. The liquid processing unit U1 develops the resist film by applying developer to the exposed surface of the workpiece W and then rinsing it away with a rinse liquid. The heat processing unit U2 performs various heat processing associated with the development processing. Specific examples of heat processing include a post-exposure bake (PEB) before the development processing and a post-exposure bake (PB) after the development processing.

A shelf unit U10 is provided on the carrier block 4 side within the processing block 5. The shelf unit U10 is divided into multiple cells arranged vertically. A transport device A7 including a lifting arm is provided near the shelf unit U10. The transport device A7 raises and lowers the workpiece W between the cells of the shelf unit U10.

A shelf unit U11 is provided on the interface block 6 side of the processing block 5. The shelf unit U11 is divided into multiple cells arranged vertically.

The interface block 6 transfers the workpiece W to and from the exposure device 3. For example, the interface block 6 incorporates a transport device A8 including a transfer arm, and is connected to the exposure device 3. The transport device A8 transfers the workpiece W placed on the shelf unit U11 to the exposure device 3. The transport device A8 receives the workpiece W from the exposure device 3 and returns it to the shelf unit U11.

The control device 18 controls the coating/developing device 2 to perform the coating/developing process, for example, in the following procedure. First, the control device 18 controls the transport device A1 to transport the workpiece W in the carrier C to the shelf unit U10, and then controls the transport device A7 to place the workpiece W in the cell for the processing module 11.

Next, the control device 18 controls the transport device A3 to transport the workpiece W from the shelf unit U10 to the liquid processing unit U1 and heat processing unit U2 in the processing module 11. The control device 18 also controls the liquid processing unit U1 and heat processing unit U2 to form an underlayer film on the surface of the workpiece W. The control device 18 then controls the transport device A3 to return the workpiece W with the underlayer film formed to the shelf unit U10, and controls the transport device A7 to place the workpiece W in a cell for the processing module 12.

Next, the control device 18 controls the transport device A3 to transport the workpiece W from the shelf unit U10 to the liquid processing unit U1 and heat processing unit U2 in the processing module 12. The control device 18 also controls the liquid processing unit U1 and heat processing unit U2 to form a resist film on the surface of the workpiece W. The control device 18 then controls the transport device A3 to return the workpiece W to the shelf unit U10, and controls the transport device A7 to place the workpiece W in the cell for the processing module 13.

Next, the control device 18 controls the transport device A3 to transport the workpiece W from the shelf unit U10 to each unit in the processing module 13. The control device 18 also controls the liquid processing unit U1 and the heat processing unit U2 to form an upper layer film on the resist film of the workpiece W. The control device 18 then controls the transport device A3 to transport the workpiece W to the shelf unit U11.

Next, the control device 18 controls the transport device A8 to send the workpiece W from the shelf unit U11 to the exposure device 3. The control device 18 then controls the transport device A8 to receive the exposed workpiece W from the exposure device 3 and place it in a cell for the processing module 14 in the shelf unit U11.

Next, the control device 18 controls the transport device A3 to transport the workpiece W from the shelf unit U11 to each unit in the processing module 14, and controls the liquid processing unit U1 and heat processing unit U2 to perform a development process on the resist film on the workpiece W. The control device 18 then controls the transport device A3 to return the workpiece W to the shelf unit U10, and controls the transport devices A7 and A1 to return the workpiece W into the carrier C. This completes the coating and developing process for one workpiece W. The control device 18 then causes the coating and developing device 2 to perform the above coating and developing process on each of the subsequent multiple workpieces W.

(liquid processing unit)
Next, an example of the liquid processing unit U1 will be described in detail with reference to Figures 3 and 4. Here, the liquid processing unit U1 in the processing module 12 that forms a resist film will be described as an example. As shown in Figure 3, the liquid processing unit U1 has a spin holder 20 and a processing liquid supply unit 30.

The rotating holding unit 20 holds and rotates the workpiece W based on operational instructions from the control device 18. The rotating holding unit 20 includes, for example, a holding unit 22 and a rotation drive unit 24. The holding unit 22 supports the center of the workpiece W, which is placed horizontally with its surface Wa facing up, and holds the workpiece W, for example, by vacuum suction. The rotation drive unit 24 is an actuator that includes a power source such as an electric motor, and rotates the holding unit 22 around a vertical axis Ax. This causes the workpiece W on the holding unit 22 to rotate.

The processing liquid supply unit 30 supplies processing liquid to the surface Wa of the workpiece W by ejecting the processing liquid toward the surface Wa based on operational instructions from the control device 18. The processing liquid supplied by the processing liquid supply unit 30 is a substrate processing solution used to process the workpiece W. Examples of processing liquid include a solution (resist) used to form a resist film and a solution (e.g., thinner) used in a pre-wetting process to increase the wettability of the surface Wa to the resist. The processing liquid supply unit 30 has, for example, multiple nozzles 32, a holding head 34, and a supply unit 36.

The multiple nozzles 32 each eject processing liquid onto the surface Wa of the workpiece W held in the holder 22. The multiple nozzles 32 are, for example, positioned above the workpiece W while held by a holding head 34, and individually eject processing liquid downward. The holding head 34 may be configured to be movable in a direction along the surface Wa of the workpiece W by a drive unit (not shown). The number of multiple nozzles 32 is not limited, but the following description will be given taking as an example a case where the processing liquid supply unit 30 has 12 nozzles 32 (hereinafter referred to as "nozzles 32A to 32L").

A processing liquid is supplied to each of the nozzles 32A to 32L from the supply unit 36. Different types of processing liquid may be supplied to each of the nozzles 32A to 32L from the supply unit 36. As an example, different types of resist may be supplied to each of the nozzles 32A to 32J from the supply unit 36, and different types of thinner may be supplied to each of the nozzles 32K and 32L from the supply unit 36.

As shown in FIG. 4, the supply unit 36 includes multiple supply pipes 42A-42L and multiple supply sources 44A-44L. The supply pipe 42A forms a flow path between the nozzle 32A and the supply source 44A, which is the source of the treatment liquid supplied to (discharged from) the nozzle 32A. The supply source 44A includes, for example, a bottle that stores the treatment liquid and a pump that pressure-feeds the treatment liquid from the bottle toward the nozzle 32A. Like the supply pipe 42A, the supply pipes 42B-42L also form flow paths between the supply sources 44B-44L, which are the sources of the treatment liquid, and the nozzles 32B-32L, respectively.

The supply unit 36 further includes multiple on-off valves V provided in the multiple supply pipes 42A-42L, respectively. The on-off valves V are switched between an open state and a closed state based on operational instructions from the control device 18. By switching the on-off states of the multiple on-off valves V, the flow paths of the supply pipes 42A-42L are opened and closed, respectively. For example, when the on-off valve V is in the open state, the processing liquid flows through the flow paths of the supply pipes 42A-42L, and the processing liquid is ejected from the nozzles 32A-32L onto the surface Wa of the workpiece W.

(Foreign object detection unit)
The coating/developing apparatus 2 further includes a foreign matter detection unit 50 (foreign matter detection device) configured to detect foreign matter (particles) contained in the processing liquid supplied to the workpiece W. The foreign matter detection unit 50 is configured, for example, to detect foreign matter in each of the processing liquids flowing through the flow paths of the multiple supply pipes 42A-42L. The foreign matter detection unit 50 may be disposed near the liquid processing unit U1 or may be disposed within the housing of the liquid processing unit U1. Some elements of the foreign matter detection unit 50 may be provided between the on-off valve V and the nozzles 32A-32L on the flow paths of the supply pipes 42A-42L. An example of the foreign matter detection unit 50 will be described below with reference to FIGS. 5 to 10 .

The foreign object detection unit 50 forms a flow path (hereinafter referred to as the "treatment liquid flow path") through which the treatment liquid flows through each of the supply pipes 42A-42L. The foreign object detection unit 50 detects foreign objects in the treatment liquid flowing through the treatment liquid flow path by receiving light generated by irradiating the treatment liquid flow path with irradiation light (e.g., laser light). As shown in FIG. 5, the foreign object detection unit 50 includes, for example, a housing 52 and a detection unit 53. The housing 52 includes a top wall 54a, a bottom wall 54b, and side walls 56a-56d (see also FIG. 7). As an example, the top wall 54a and the bottom wall 54b are each arranged horizontally (along the X-Y plane). Furthermore, the side walls 56a and 56b are each arranged vertically (along the Y-Z plane) along the Y-axis direction and face each other in the X-axis direction (first direction). Additionally, side walls 56c and 56d are arranged vertically along the X-axis direction (along the X-Z plane) and face each other in the Y-axis direction (second direction). Housing 52 houses detection unit 53. Detection unit 53 has a flow path forming unit 60 and a measurement unit 70.

The flow path forming unit 60 forms multiple treatment liquid flow paths that are respectively provided on the flow paths of the supply pipes 42A-42L. Each of the multiple treatment liquid flow paths formed by the flow path forming unit 60 is used to detect foreign matter contained in the treatment liquid flowing through that treatment liquid flow path. For example, as shown in FIG. 6, the flow path forming unit 60 has multiple treatment liquid flow path forming units 62A-62L. The multiple treatment liquid flow path forming units 62A-62L are configured similarly to one another. Below, the details of the treatment liquid flow path forming units are explained using the treatment liquid flow path forming unit 62A as an example.

As shown in FIG. 5, the processing liquid flow path forming portion 62A forms a processing liquid flow path 64 on the flow path of the supply pipe 42A that connects the supply source 44A and the nozzle 32A (see also FIG. 4). The upstream and downstream ends of the processing liquid flow path 64 are connected to the supply pipe 42A. As a result, the processing liquid pressure-fed from the supply source 44A passes through a portion of the flow path of the supply pipe 42A, the processing liquid flow path 64 of the processing liquid flow path forming portion 62A, and the remaining portion of the flow path of the supply pipe 42A, in that order, before being ejected from the nozzle 32A onto the surface Wa of the workpiece W.

The treatment liquid flow path forming portion 62A includes, for example, a block body 66 in which the treatment liquid flow path 64 is formed. The block body 66 is made of a material that is transparent to the laser light used for foreign matter detection. Examples of materials that can be used to form the block body 66 include quartz and sapphire. The block body 66 may be formed in a rectangular parallelepiped shape, and one face of the block body 66 may face the side wall 56a. As an example, an inlet 64a and an outlet 64b of the treatment liquid flow path 64 are formed on the face of the block body 66 facing the side wall 56a. The inlet 64a may be located below the outlet 64b.

The treatment liquid flow path 64 includes, for example, a first flow path 68a, a second flow path 68b, and a third flow path 68c. The first flow path 68a is formed to extend horizontally (along the X-axis direction in the figure) along the bottom wall 54b. One end of the first flow path 68a, close to the side wall 56a, forms the inlet 64a, and the other end of the first flow path 68a, close to the side wall 56b, is connected to the second flow path 68b. The second flow path 68b is formed to extend vertically along the side wall 56a (along the Z-axis direction). One end of the second flow path 68b, close to the bottom wall 54b, is connected to the first flow path 68a, and the other end of the second flow path 68b, close to the top wall 54a, is connected to the third flow path 68c. The third flow path 68c is formed to extend horizontally (along the X-axis direction) along the bottom wall 54b. One end of the third flow path 68c near the side wall 56b is connected to the second flow path 68b, and the other end of the third flow path 68c near the side wall 56a forms the outlet 64b.

The inlet 64a is connected to a supply pipe 42A that is upstream of the processing liquid flow path forming section 62A (hereinafter referred to as the "upstream supply pipe 46"). The outlet 64b is connected to a supply pipe 42A that is downstream of the processing liquid flow path forming section 62A (hereinafter referred to as the "downstream supply pipe 48"). The upstream supply pipe 46 and the downstream supply pipe 48 penetrate the opposing side wall 56a of the block body 66. With the above configuration, the processing liquid delivered from the supply source 44A passes through the upstream supply pipe 46, first flow path 68a, second flow path 68b, third flow path 68c, and downstream supply pipe 48 in this order, and is supplied to the workpiece W from the nozzle 32A.

As described above, the treatment liquid flow path forming sections 62A-62L shown in FIG. 6 are configured similarly to one another. Therefore, like the treatment liquid flow path forming section 62A, the treatment liquid flow path forming sections 62B-62L each include a block main body 66 with a treatment liquid flow path 64 formed therein. The treatment liquid flow path 64 of each of the treatment liquid flow path forming sections 62B-62L includes a first flow path 68a, a second flow path 68b, and a third flow path 68c. The upstream supply pipes 46 of the supply pipes 42B-42L are connected to the inlets 64a (first flow paths 68a) of the treatment liquid flow path forming sections 62B-62L, respectively. The downstream supply pipes 48 of the supply pipes 42B-42L are connected to the outlets 64b (third flow paths 68c) of the treatment liquid flow path forming sections 62B-62L, respectively.

The treatment liquid flow path forming sections 62A-62L are arranged side by side in the direction from side wall 56d to side wall 56c (along the Y-axis direction), facing the side wall 56a. The treatment liquid flow path forming sections 62A-62L may be arranged in this order with a gap between them. The height positions (positions in the Z-axis direction) of the first flow paths 68a of the treatment liquid flow path forming sections 62A-62L may be approximately the same. The distances (positions in the X-axis direction) of the second flow paths 68b of the treatment liquid flow path forming sections 62A-62L from the side wall 56a may be approximately the same. The height positions (distances from the bottom wall 54b) of the third flow paths 68c of the treatment liquid flow path forming sections 62A-62L may be approximately the same.

Returning to FIG. 5, the measurement unit 70 is configured to receive light emitted from the treatment liquid flow path 64 when the treatment liquid flow path 64 is irradiated with light from the light source 72. The measurement unit 70 includes, for example, a light source 72, an irradiation unit 74, a light receiving unit 76, a holding unit 78, and a drive unit 80. The light source 72 generates laser light as irradiation light for detecting foreign matter in the treatment liquid. The light source 72 emits laser light, for example, with a wavelength of approximately 400 nm to 600 nm and an output of approximately 600 mW to 1000 mW. As shown in FIG. 7, the light source 72 is provided on the bottom wall 54b, for example, and is positioned below the treatment liquid flow path forming units 62A to 62L. For example, the light source 72 emits laser light in a direction from the side wall 56d toward the side wall 56c (negative Y-axis direction). The light source 72 is positioned at a different position in the Y-axis direction from the treatment liquid flow path forming unit 62A. The light source 72 is positioned at a distance from the treatment liquid flow path forming portion 62A in the Y-axis direction. For example, the light source 72 and the treatment liquid flow path forming portions 62A-62L are arranged in this order in the Y-axis direction.

The irradiation unit 74 is configured to irradiate the irradiation light from the light source 72 toward each of the treatment liquid flow paths 64 of the treatment liquid flow path forming units 62A to 62L. The irradiation unit 74 is configured, for example, to individually irradiate the irradiation light toward each of the treatment liquid flow paths 64 of the treatment liquid flow path forming units 62A to 62L. The irradiation unit 74 may be disposed below the treatment liquid flow paths 64. The irradiation unit 74 has an optical member 82 configured, for example, to change the direction of the irradiation light from the light source 72 so that the irradiation light is irradiated toward each of the treatment liquid flow paths 64.

The optical member 82 includes, for example, a reflecting member 82a and a condensing lens 82b. The reflective surface of the reflecting member 82a faces the light source 72 in the Y-axis direction. The reflective surface of the reflecting member 82a reflects the irradiation light emitted substantially horizontally from the light source 72 upward. The condensing lens 82b is disposed above the reflecting member 82a and condenses the irradiation light reflected by the reflecting member 82a at a measurement position set in the treatment liquid flow path 64. The condensing lens 82b is configured, for example, to irradiate the irradiation light at a measurement position set in the first flow path 68a of the treatment liquid flow path 64.

The holding portion 78 movably holds the optical element 82. The holding portion 78 includes, for example, a guide rail 88 and a slide base 84. The guide rail 88 is provided on the bottom wall 54b and is formed to extend in the direction from the side wall 56c toward the side wall 56d (along the Y-axis direction). For example, as shown in FIG. 7, the guide rail 88 may extend in the Y-axis direction at least between the treatment liquid flow path forming portion 62A and the treatment liquid flow path forming portion 62L. The guide rail 88 movably supports the slide base 84.

The slide base 84 is positioned below the treatment liquid flow path forming sections 62A-62L and supports the optical member 82 (reflecting member 82a). As shown in FIG. 5, the slide base 84 may be formed to extend in a direction intersecting the guide rail 88 (e.g., the X-axis direction). For example, when viewed from the side, one end of the slide base 84 near the side wall 56a is located below the treatment liquid flow path forming section 62A, and the other end near the side wall 56b is located closer to the side wall 56b than the treatment liquid flow path forming section 62A. As an example, the optical member 82 is positioned at one end of the slide base 84 near the side wall 56a.

The drive unit 80 uses a power source such as an electric motor to move the slide table 84 along the guide rails 88. As the slide table 84 moves along the guide rails 88, the irradiation unit 74 (optical member 82) moves along the Y-axis direction.

The light receiving unit 76 is configured to receive the light emitted from the processing liquid flow paths 64 of the processing liquid flow path forming units 62A-62L in response to irradiation light from the irradiation unit 74. The light receiving unit 76 is configured, for example, to individually receive the light emitted from the processing liquid flow paths 64 of the processing liquid flow path forming units 62A-62L. The light receiving unit 76 may be positioned so that the processing liquid flow path forming units 62A-62L are sandwiched between it and the side wall 56a.

The light receiving unit 76 includes, for example, an optical member 92 and a light receiving element 94. In the direction from side wall 56a toward side wall 56b (the X-axis direction), the treatment liquid flow path forming unit 62A, the optical member 92, and the light receiving element 94 are arranged in this order. The height positions of the optical member 92 and the light receiving element 94 are, for example, approximately the same as the height position of the first flow path 68a of the treatment liquid flow path 64.

The optical member 92 includes, for example, a focusing lens that focuses light emitted from the treatment liquid flow path 64 (hereinafter referred to as "emitted light") toward the light-receiving element 94. A wavelength filter that passes only light having a specific wavelength may be provided inside the optical member 92. The light-receiving element 94 receives the emitted light focused by the optical member 92 and generates an electrical signal corresponding to the received light (detection light). The light-receiving element 94 includes, for example, a photodiode that performs photoelectric conversion.

The optical member 92 and the light receiving element 94 are attached to a support member 86 that extends vertically. The support member 86 is connected to the slide base 84. For example, the lower end of the support member 86 is connected to the end of the slide base 84 opposite the end where the optical member 82 is provided. As the drive unit 80 moves the slide base 84, the optical member 92 and the light receiving element 94 move along the Y-axis direction.

With the above configuration, the drive unit 80 moves the slide table 84, thereby moving both the irradiation unit 74 and the light receiving unit 76 along the Y-axis direction. The drive unit 80 moves the irradiation unit 74 and the light receiving unit 76, for example, between a position where the irradiation unit 74 and the light receiving unit 76 each face the treatment liquid flow path forming unit 62A, and a position where the irradiation unit 74 and the light receiving unit 76 each face the treatment liquid flow path forming unit 62L. Hereinafter, the positions where the irradiation unit 74 and the light receiving unit 76 each face one of the treatment liquid flow path forming units will be referred to as the positions corresponding to that treatment liquid flow path forming unit.

As an example, while the light source 72 continues to irradiate the optical member 82, the drive unit 80 moves the optical member 82 below one of the treatment liquid flow paths 64 of the treatment liquid flow path forming units 62A-62L, causing the irradiation unit 74 to irradiate that treatment liquid flow path 64 with irradiation light. At this time, the light receiving element 94 receives the light emitted from that treatment liquid flow path 64.

As described above, the irradiation unit 74 is disposed below the measurement position set in the treatment liquid flow path 64, and the light-receiving unit 76 is disposed to the side of the measurement position. Therefore, when irradiation light is irradiated into one of the treatment liquid flow paths 64, the light-receiving unit 76 receives a portion of the emitted light (scattered light) generated by scattering the irradiation light at the measurement position within the treatment liquid flow path 64. Scattered light is generated when irradiation light is irradiated into the treatment liquid flow path 64 through which the treatment liquid flows. If the treatment liquid does not contain foreign matter, most of the irradiation light passes through the treatment liquid flow path 64. On the other hand, if the treatment liquid contains foreign matter, the degree of scattering of the irradiation light within the treatment liquid flow path 64 increases, and the intensity of the light received by the light-receiving unit 76 (the portion of the scattered light directed toward the light-receiving unit 76) is greater than when no foreign matter is present. If the treatment liquid is a resist, the treatment liquid typically contains a base resin (base polymer) as a major component. This base polymer can also scatter the irradiated light, so the light receiving unit 76 can receive light with a certain degree of amplitude even if the treatment liquid does not contain foreign matter.

The foreign matter detection unit 50 may further include a control unit 100. The control unit 100 controls each element (detection unit 53) of the foreign matter detection unit 50. The control unit 100 is disposed, for example, inside the housing 52. As an example, the control unit 100 controls each element of the foreign matter detection unit 50 based on operational instructions from the control device 18. The control unit 100 is configured to at least determine whether the processing liquid contains foreign matter based on the signal intensity of the emitted light emitted from the processing liquid flow path 64 when the light source 72 irradiates the processing liquid flow path 64 through which the processing liquid supplied to the workpiece W flows, and to obtain intensity information indicating the intensity of the background light contained in the emitted light based on the signal intensity of the emitted light.

As shown in FIG. 8, the control unit 100 has, as its functional configuration (hereinafter referred to as "functional modules"), for example, a signal acquisition unit 102, a foreign object determination unit 104, a processing information acquisition unit 106, a drive control unit 108, an intensity information acquisition unit 122, a reference information storage unit 112, a status monitoring unit 124, and an output unit 116. The processes performed by the signal acquisition unit 102, foreign object determination unit 104, processing information acquisition unit 106, drive control unit 108, intensity information acquisition unit 122, reference information storage unit 112, status monitoring unit 124, and output unit 116 correspond to the processes performed by the control unit 100.

The signal acquisition unit 102 acquires an electrical signal corresponding to the intensity of the emitted light from the light receiving unit 76. The signal acquisition unit 102 acquires, for example, an electrical signal from the light receiving element 94 corresponding to the intensity of the emitted light emitted from the treatment liquid flow path 64 (first flow path 68a) through which the treatment liquid to be monitored flows, among the treatment liquid flow path forming units 62A-62L. The signal acquisition unit 102 acquires, for example, an electrical signal having an amplitude corresponding to the intensity of the emitted light. The signal acquisition unit 102 may acquire the electrical signal at a predetermined sampling period.

The foreign matter determination unit 104 detects the presence or absence of foreign matter in the processing liquid based on the intensity (hereinafter referred to as "signal intensity"), such as the amplitude, of the electrical signal corresponding to the emitted light. Figure 9 shows a graph illustrating an example of the time variation of the signal intensity obtained from the signal acquisition unit 102. As described above, the degree of scattering of the irradiated light within the processing liquid flow path 64 (within the processing liquid) varies depending on the presence or absence of foreign matter, and therefore the magnitude of the signal intensity also varies depending on the presence or absence of foreign matter. As shown in Figure 9, the electrical signal corresponding to the emitted light may include a signal Ib corresponding to the background light when no foreign matter is present, and a signal Is corresponding to the light scattered from the foreign matter when the foreign matter is present (more specifically, a signal Is corresponding to the background light and the light scattered by the foreign matter). The signal Ib corresponding to the background light may include a component corresponding to the scattered light from substances normally contained in the processing liquid (e.g., the base polymer described above) and a component corresponding to external disturbances.

For example, as shown in FIG. 9, the foreign matter determination unit 104 determines that foreign matter is present in the processing liquid when the signal strength is greater than a predetermined threshold value Th. The foreign matter determination unit 104 determines that foreign matter is not present in the processing liquid when the signal strength is equal to or less than the predetermined threshold value Th. The threshold value Th is a value that is set in advance taking into account the intensity of scattered light when irradiated light is scattered by foreign matter in the processing liquid. The foreign matter determination unit 104 may determine the presence or absence of foreign matter in the processing liquid for each sampling period in which the signal acquisition unit 102 acquires signal strength.

The processing information acquisition unit 106 acquires information about the processing performed in the liquid processing unit U1 (hereinafter referred to as "processing information") from the control device 18. The processing information includes, for example, information indicating the nozzle from which ejection is performed in the liquid processing unit U1 (the processing liquid for which foreign matter is detected), and information indicating the timing and duration of supply of the processing liquid. The processing information acquisition unit 106 may acquire processing information from the control device 18 for each process using a processing liquid before supply of that processing liquid begins.

The drive control unit 108 moves the irradiation unit 74 and light receiving unit 76 by moving the slide table 84 using the drive unit 80 between the treatment liquid flow path forming unit 62A and the treatment liquid flow path forming unit 62L. For example, the drive control unit 108 moves the irradiation unit 74 and light receiving unit 76 using the drive unit 80 to positions corresponding to the treatment liquid flow path 64 through which the treatment liquid passes, among the treatment liquid flow path forming units 62A-62L, depending on the treatment liquid to be detected indicated by the treatment information. The drive control unit 108 may also move the irradiation unit 74 and light receiving unit 76 using the drive unit 80 to positions corresponding to the treatment liquid flow path 64 before the supply of the treatment liquid to be detected begins.

The intensity information acquisition unit 122 acquires information indicating the intensity of background light contained in the emitted light (hereinafter referred to as "intensity information") based on the signal intensity. The intensity information acquisition unit 122 may acquire the time average of the signal intensity included in a predetermined period as intensity information based on the signal intensity acquired by the signal acquisition unit 102 at a predetermined sampling period. The intensity information acquisition unit 122 may, for example, calculate the time average of the acquired values of the signal intensity included in the predetermined period once the predetermined period has passed. The intensity information acquisition unit 122 may calculate the average value of the acquired values of the signal intensity included in the predetermined period as the time average, or may calculate the integrated value obtained by integrating the time change in the signal intensity included in the predetermined period as the time average.

Instead of a time average, the intensity information acquisition unit 122 may acquire the signal intensity value (instantaneous value) for each sampling period as the intensity information. The intensity information acquisition unit 122 may acquire the maximum, median, minimum, or mode of the signal intensities acquired over a predetermined period as the intensity information. The intensity information acquisition unit 122 may acquire the signal intensity (baseline value) corresponding to scattered light derived from substances normally contained in the treatment liquid (for example, the above-mentioned base polymer, etc.) as the intensity information. The intensity information acquisition unit 122 may acquire the magnitude of a specific frequency component in the frequency distribution obtained by frequency analysis of the signal intensity acquired over a predetermined period as the intensity information. The predetermined period may be determined in advance, for example, by an operator.

The reference information storage unit 112 stores reference information for checking the state of the treatment liquid being ejected or the state of the foreign matter detection unit 50 (detection unit 53). The reference information storage unit 112 may store (store), for example, the intensity of background light acquired when the treatment liquid and detection unit 53 are operating normally (hereinafter referred to as "reference intensity"). For example, the reference intensity may be set in advance in the reference information storage unit 112 by an operator, or a process may be performed to acquire intensity information when the treatment liquid and detection unit 53 are operating normally.

The status monitoring unit 124 may monitor (determine) whether the status of at least one of the processing liquid and the detection unit 53 is normal by comparing the intensity information acquired by the intensity information acquisition unit 122 with a reference intensity. If the status of the processing liquid and the detection unit 53 is constant, the intensity of the background light is expected to fall within a certain range. However, for example, if the type of processing liquid being detected for foreign matter is different, the intensity of the background light will also differ. The intensity of the background light will also differ if other solutions are mixed into the processing liquid being detected for foreign matter, or if the processing liquid has deteriorated. Therefore, the status monitoring unit 124 may monitor whether the type of processing liquid is appropriate based on the intensity information, or may monitor whether the processing liquid has deteriorated or whether other solutions have been mixed into it.

If the state of the optical system included in the detection unit 53 is constant, it is thought that the intensity of the background light will fall within a certain range. However, for example, the intensity of the background light will change due to changes over time (deterioration) of the optical system of the detection unit 53. Examples of optical system deterioration include a decrease in the output of the laser light from the light source 72, deterioration of lens performance due to clouding or dirt on the focusing lens or deterioration of the anti-reflection coating, and misalignment of the optical axis of the optical system due to external impact or thermal expansion. The status monitoring unit 124 may monitor the state of the optical system of the detection unit 53 based on the intensity information.

For example, the status monitoring unit 124 may determine that the status of the processing liquid and the detection unit 53 is normal if the intensity indicated by the intensity information is within a range obtained by adding an allowable error to a reference intensity, and may determine that the status of at least one of the processing liquid and the detection unit 53 is abnormal if the intensity is outside that range. The status monitoring unit 124 may, for example, perform the above comparison and determination for each predetermined period for calculating the time average, or may perform the above comparison and determination for each supply of processing liquid.

The output unit 116 outputs the determination result and the monitoring result to the outside of the foreign matter detection unit 50. The output unit 116 may output the foreign matter detection determination result and the monitoring result of the state of at least one of the processing liquid and the detection unit 53 to the control device 18, or may output them to a display or the like that notifies an operator of the results. For example, if the foreign matter determination unit 104 determines that a foreign matter is contained, the output unit 116 outputs an alarm signal indicating that the processing liquid being monitored contains a foreign matter. Alternatively, if the output unit 116 determines that the state of at least one of the processing liquid and the detection unit 53 is abnormal, it outputs an alarm signal indicating that the state is abnormal.

The control unit 100 is composed of one or more control computers. For example, the control unit 100 has a circuit 200 shown in FIG. 10. The circuit 200 has one or more processors 202, memory 204, storage 206, input/output ports 208, and a timer 212. The storage 206 has a computer-readable storage medium, such as a hard disk. The storage medium stores a program for causing the control unit 100 to execute the foreign object detection method described below. The storage medium may be a removable medium such as a non-volatile semiconductor memory, magnetic disk, or optical disk. The memory 204 temporarily stores the program loaded from the storage medium of the storage 206 and the results of calculations performed by the processor 202.

The processor 202 configures each functional module by executing the above programs in cooperation with the memory 204. The input/output port 208 inputs and outputs electrical signals between the control device 18, the light receiving unit 76, the drive unit 80, etc. in accordance with instructions from the processor 202. The timer 212 measures elapsed time, for example, by counting reference pulses at a fixed interval. Note that the hardware configuration of the control unit 100 is not necessarily limited to configuring each functional module using a program. For example, each functional module of the control unit 100 may be configured using a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) that integrates such logic circuits.

[Foreign object detection method]
Next, a foreign matter detection method (foreign matter detection procedure) by the foreign matter detection unit 50 will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of a foreign matter detection method executed in substrate processing including one supply of processing liquid.

When the processing information acquisition unit 106 acquires processing information from the control device 18 while the irradiation of irradiation light from the light source 72 continues, the control unit 100 executes step S01. In step S01, for example, the drive control unit 108 moves the slide table 84 using the drive unit 80 to a position corresponding to the processing liquid flow path 64 through which the processing liquid for which foreign matter detection is to be performed, as indicated by the processing information, thereby moving the irradiation unit 74 and the light receiving unit 76. As a result, irradiation light is irradiated from the irradiation unit 74 onto the processing liquid flow path 64 through which the processing liquid for which foreign matter detection is to be performed flows, and the light emitted from the processing liquid flow path 64 is received by the light receiving unit 76. The supply of the processing liquid indicated by the processing information to the workpiece W may be started before execution of step S01 or at approximately the same timing as step S01.

Next, the control unit 100 executes steps S02 and S03. In step S02, for example, the signal acquisition unit 102 acquires the signal intensity corresponding to the detection light received by the light receiving unit 76. In step S03, for example, the foreign matter determination unit 104 determines whether the signal intensity obtained in step S02 is greater than the threshold value Th. If it is determined in step S03 that the signal intensity is greater than the threshold value Th (step S03: YES), the control unit 100 executes step S04. In step S04, for example, the output unit 116 outputs an alarm signal indicating that the processing liquid being detected for foreign matter contains foreign matter. On the other hand, if it is determined in step S03 that the signal intensity is equal to or less than the threshold value Th (step S03: NO), the control unit 100 does not execute step S04.

Next, the control unit 100 executes step S05. In step S05, for example, the control unit 100 determines whether the supply of the processing liquid being monitored has ended. The control unit 100 may determine whether the supply of the processing liquid has ended by measuring the elapsed time from the supply start timing included in the processing information. If it is determined in step S05 that the supply of the processing liquid being monitored has not ended (step S05: NO), the control unit 100 repeats the processes of steps S02 and S03. As a result, monitoring for the presence of foreign matter in the processing liquid continues during the supply period of the processing liquid, and the signal acquisition unit 102 acquires the signal intensity corresponding to the detection light at a predetermined sampling period.

If it is determined in step S05 that the supply of the monitored processing liquid has ended (step S05: YES), the control unit 100 executes step S06. In step S06, the intensity information acquisition unit 122 acquires intensity information indicating the intensity of background light contained in the light emitted from the processing liquid flow path 64 based on the signal intensity. For example, the intensity information acquisition unit 122 acquires intensity information based on the signal intensity (time change in signal intensity) obtained during the above-mentioned supply period during which step S02 is repeatedly executed. As an example, the intensity information acquisition unit 122 calculates the average or integral value of the signal intensity obtained during the supply period as the intensity information.

Next, the control unit 100 executes step S07. In step S07, for example, the status monitoring unit 124 may determine whether the status of at least one of the treatment liquid and the detection unit 53 is abnormal by comparing the intensity information acquired by the intensity information acquisition unit 122 with a reference intensity. For example, the status monitoring unit 124 may determine that the status of at least one of the treatment liquid and the detection unit 53 is normal if the intensity indicated by the intensity information is within a range obtained by adding an allowable error to the reference intensity, and may determine that the status of at least one of the treatment liquid and the detection unit 53 is abnormal if the intensity indicated by the intensity information is outside of that range.

If it is determined in step S07 that the state of at least one of the processing liquid and the detection unit 53 is not normal (step S07: YES), the control unit 100 executes step S08. In step S08, for example, the output unit 116 outputs an alarm signal indicating that the state of at least one of the processing liquid and the detection unit 53 is not normal. On the other hand, if it is determined in step S08 that the state of the processing liquid and the detection unit 53 is normal (step S07: NO), the control unit 100 does not execute step S08. This completes the series of foreign matter detection procedures. The control unit 100 may execute steps S01 to S08 for each substrate processing involving the supply of processing liquid.

The above-described foreign object detection procedure is an example, and the order of steps, execution timing, execution content, etc. can be changed as appropriate. For example, in step S06, the intensity information acquisition unit 122 may calculate, for each divided period obtained by dividing the supply period in chronological order, the average or integral value of the signal intensity obtained in that divided period as the intensity information. Alternatively, the intensity information acquisition unit 122 may calculate, for one sampling period or for two or more sampling periods, the average value of the signal intensity obtained in a predetermined period prior to that period, thereby calculating a moving average of the signal intensity as the intensity information.

Instead of step S06, the intensity information acquisition unit 122 may repeatedly calculate the intensity information at the timing when step S02 is repeatedly executed. That is, the intensity information acquisition unit 122 may calculate the intensity information for each sampling period. In this case, instead of step S07, the state monitoring unit 124 may determine the state of at least one of the treatment liquid and the detection unit 53 each time the intensity information is calculated (each sampling period). As an example, the intensity information acquisition unit 122 may calculate, for each sampling period, the average value of the signal intensity obtained over a predetermined period prior to that period, thereby calculating a moving average of the signal intensity as the intensity information. Alternatively, the intensity information acquisition unit 122 may calculate, for each sampling period, the average value or integral value of the signal intensity obtained from the start of supply of the treatment liquid until that period as the intensity information.

[Effects of the embodiment]
In the foreign matter detection unit 50 or the foreign matter detection method in the foreign matter detection unit 50 exemplified above, in addition to detecting foreign matters based on the emitted light emitted from the processing liquid flow path 64 by irradiation with irradiation light, intensity information of the background light contained in the emitted light is obtained. Since the intensity information changes based on the state of the detection section 53 or the processing liquid, the foreign matter detection unit 50 can confirm whether the state of the device or the processing liquid is normal.

When detecting foreign matter in a processing liquid based on light obtained by irradiating a flow path through which the processing liquid flows, the presence or absence of foreign matter in the processing liquid is determined by detecting whether or not there is a change in the intensity of the received detection light. However, if the hardware, such as the optical system, included in the foreign matter detection device is not operating normally, or if the state of the processing liquid is different from normal, no change in the intensity of the detection light occurs, and it may be determined that no foreign matter is present in the processing liquid. The above-described foreign matter detection unit 50 can confirm the state of the processing liquid and the state of the detection section 53, including the optical system, by acquiring information about the intensity of background light, thereby ensuring more reliable foreign matter detection results. Furthermore, the signal related to the light emitted from the processing liquid flow path, which is acquired for foreign matter detection, also contains information about the background light. Therefore, the foreign matter detection unit 50 according to the above embodiment enables easy confirmation of the state of the processing liquid or device without the need for a separate configuration for status confirmation.

The light emitted from the treatment liquid flow path 64 is light that is generated when the irradiated light is scattered within the treatment liquid flow path 64. In this case, the transmitted light that passes through the treatment liquid flow path 64 is not received by the detector (light-receiving unit 76), and the intensity of the background light is also smaller than when, for example, transmitted light is received (when detection is performed using forward scattering). This makes it possible to accurately detect changes in the intensity of the detected light due to the presence or absence of foreign matter in the treatment liquid. Therefore, the above configuration makes it possible to more reliably detect foreign matter. Furthermore, because the transmitted light that passes through the treatment liquid flow path 64 is not received, it is easy to detect minute changes in the intensity of the background light.

The intensity information acquisition unit 122 acquires the time average of the signal intensity obtained over a specified period as intensity information. The intensity of the background light may vary depending on the time of acquisition. Therefore, with this configuration, the state of the device or processing liquid can be more reliably confirmed based on the time average.

The foreign matter determination unit 104 determines whether foreign matter is present in the processing liquid during the supply period from the start to the end of supply of the processing liquid to the workpiece W. The intensity information acquisition unit 122 acquires intensity information based on the signal intensity obtained during the supply period. In this case, the information obtained during the supply period can be used to efficiently check the status of the processing liquid or the detection unit 53. In other words, it is possible to check the status of the processing liquid or the device outside of the supply period without having to pass the processing liquid through to check the status.

The foreign matter detection unit 50 further includes a status monitoring unit 124 that monitors the status of at least one of the processing liquid and the detection unit 53 based on the intensity information. In this case, foreign matter detection can be performed after checking the status of the detection unit 53 or the processing liquid. This makes it possible to more reliably detect foreign matter.

In a coating/developing apparatus 2 equipped with a foreign matter detection unit 50, it is possible to check whether the condition of the foreign matter detection unit 50 and the processing liquid are normal, and by detecting foreign matter in the processing liquid in the supply section 36, defects in the workpiece W caused by foreign matter can be discovered early.

[Modification]
The light receiving unit 76 may include a plurality of light receiving elements 94 arranged in a line in the direction in which the treatment liquid flow path forming units 62A-62L are arranged (horizontal direction) or in the vertical direction. Alternatively, the light receiving unit 76 may include a plurality of light receiving elements 94 arranged two-dimensionally in the horizontal and vertical directions. For example, the light receiving unit 76 may include a photodiode array in which photodiodes are arranged one-dimensionally or two-dimensionally. The light receiving unit 76 may output a plurality of electrical signals obtained from the plurality of light receiving elements 94 to the control unit 100. The signal acquisition unit 102 may acquire the signal intensity for each electrical signal from each light receiving element 94.

In this case, the reference information storage unit 112 may acquire intensity information indicating the intensity of background light for each signal intensity obtained from the multiple light receiving elements 94. In other words, the reference information storage unit 112 may acquire intensity information for each light receiving position where the light receiving element 94 is provided. If there is an optical axis misalignment in the optical system included in the detection unit 53, it is possible that the distribution of light received by the light receiving unit 76 will differ (e.g., the light distribution will be biased). Therefore, the status monitoring unit 124 may monitor the optical axis misalignment of the optical system included in the detection unit 53 based on the intensity information for each light receiving position. For example, the status monitoring unit 124 may monitor the optical axis misalignment of the optical system (e.g., misalignment of the focal position of a focusing lens) by determining whether the difference in intensity indicated by the intensity information at multiple light receiving positions lined up in one direction is greater than a predetermined value.

The flow rate (flow speed) of the treatment liquid changes immediately after the start of ejection of the treatment liquid and immediately before the end of ejection. As the flow rate changes, the intensity of the background light contained in the emitted light also changes. Therefore, during the supply period from the start of supply of the treatment liquid to the end of supply, the change in the intensity of the background light changes over time in accordance with the change in the flow rate (flow speed) during the supply period. The status monitoring unit 124 may monitor whether the treatment liquid is being ejected normally (whether the flow rate of the treatment liquid is within a set range) in accordance with the change in the intensity of the background light during the supply period.

The intensity information acquisition unit 122 may perform a correction process to remove the influence of the signal Is based on scattered light from foreign matter. For example, the intensity information acquisition unit 122 may exclude a signal strength as an abnormal value when the signal strength is greater than the same value as the threshold value Th or a different value (another threshold value). Alternatively, the intensity information acquisition unit 122 may exclude a signal strength as an abnormal value when the difference between the signal strength and the calculated moving average is greater than a predetermined value.

In the above example, the status of the processing liquid and the detection unit 53 is monitored by the control unit 100, but status monitoring may also be performed by an operator instead of the control unit 100. In this case, the control unit 100 may output the acquired (calculated) background light intensity information to the outside, and the operator may monitor the status by comparing the output intensity information with reference information.

At least a portion of the treatment liquid flow path 64 that flows through the block main body 66 may be formed to extend in a direction other than horizontal or vertical. The inlet 64a and outlet 64b of the treatment liquid flow path 64 may be formed on different surfaces of the block main body. The treatment liquid flow paths 64 of the treatment liquid flow path forming portions 62A to 62L may be configured to be different from each other.

Instead of the block body 66, the treatment liquid flow path forming sections 62A-62L may include a supply liquid passage pipe through which the treatment liquid flows. The treatment liquid flow path 64 may be a flow path within the supply liquid passage pipe. This liquid passage pipe may be formed from a material that is transparent to irradiation light (e.g., quartz or sapphire). The foreign matter detection unit 50 may have a single treatment liquid flow path forming section instead of the treatment liquid flow path forming sections 62A-62L.

The foreign object detection unit 50 may include an irradiation drive unit that moves the irradiation unit 74 along the Y-axis direction, and a light-receiving drive unit that moves the light-receiving unit 76 along the Y-axis direction. These two drive units may be configured to move the irradiation unit 74 and the light-receiving unit 76 along the Y-axis direction. The irradiation unit 74 may include a light source 72, and irradiation light may be irradiated onto each of the treatment liquid flow paths 64 of the treatment liquid flow path forming units 62A-62L without passing through the optical member 82.

The light receiving unit 76 may receive a portion of the transmitted light obtained when the irradiation light from the irradiation unit 74 passes through the treatment liquid flow path 64. In this case, the irradiation unit 74 and the light receiving unit 76 may be arranged so that the treatment liquid flow path forming units 62A-62L are sandwiched between them in the vertical direction (Z-axis direction).

In the above example, the intensity information acquisition unit 122 acquires background light intensity information based on the signal intensity of scattered light obtained during the supply period of the treatment liquid. However, the intensity information acquisition unit 122 may also acquire intensity information based on signal intensity obtained when no treatment liquid is being supplied. Specifically, the intensity information acquisition unit 122 may acquire intensity information based on signal intensity obtained when the treatment liquid flow path 64 is filled with treatment liquid (treatment liquid is present in the treatment liquid flow path 64) and no treatment liquid is being supplied to the workpiece W. For example, after the on-off valve V shown in FIG. 4 is closed to stop the supply of treatment liquid to the workpiece W, the flow path between the on-off valve V and the nozzle (treatment liquid flow path 64) is filled with treatment liquid that has not been ejected from the nozzle. In this state, the signal acquisition unit 102 may acquire signal intensity corresponding to scattered light from the treatment liquid flow path 64 in which the flow of treatment liquid has stopped, and the intensity information acquisition unit 122 may acquire intensity information based on the signal intensity.

The intensity information acquisition unit 122 (control unit 100) may acquire intensity information based on signal intensity during the above-mentioned supply periods, or based on signal intensity during non-supply periods when processing liquid is not being supplied, or may do both. When acquiring intensity information during both supply periods and non-supply periods, the control unit 100 may acquire intensity information based on signal intensity during non-supply periods if the length between one supply period and the next (length of the non-supply period) is longer than a predetermined time. When acquiring intensity information only during supply periods, the period during which processing liquid or equipment is not confirmed based on intensity information (unconfirmed time) depends on the length of the non-supply period determined by the processing schedule. In contrast, when intensity information is acquired during both periods, the length of the unconfirmed time can be adjusted independently of the length determined by the processing schedule.

In this modified example, the intensity information acquisition unit 122 acquires intensity information based on the signal intensity obtained when the processing liquid flow path 64 is filled with processing liquid and the processing liquid is not being supplied to the workpiece W. In this case, disturbance components that may be contained in the background light due to the processing liquid flowing through the processing liquid flow path 64 can be reduced, allowing for more accurate confirmation of the state of the device or processing liquid.

The specific configuration of the substrate processing apparatus is not limited to the configuration of the coating/developing apparatus 2 exemplified above. Any substrate processing apparatus may be used as long as it is equipped with a foreign matter detection unit 50 that detects foreign matter in the processing liquid supplied to the substrate. The processing liquid monitored by the foreign matter detection unit 50 may be a solution for forming a film other than a resist film (for example, the above-mentioned underlayer film or overlayer film), or may be a solution for substrate processing other than film formation. All or part of the functional modules of the control unit 100 of the foreign matter detection unit 50 may be executed by the control device 18. In this case, the foreign matter detection unit 50 and the control device 18 may constitute a foreign matter detection apparatus.

1...substrate processing system, 2...coating/developing apparatus, 30...processing liquid supply section, 32A to 32L...nozzles, 36...supply section, 50...foreign matter detection unit, 53...detection section, 60...flow path forming section, 62A to 62L...processing liquid flow path forming section, 64...processing liquid flow path, 72...light source, 74...irradiation section, 76...light receiving section, 100...control section, 122...intensity information acquisition section, 124...status monitoring section, U1...liquid processing unit, W...work

Claims (9)

a detection unit including a flow path forming unit that forms a processing liquid flow path through which a processing liquid supplied to a substrate flows, and a measurement unit configured to receive light emitted from the processing liquid flow path when light from a light source is irradiated onto the processing liquid flow path;
a foreign matter determining unit that determines whether or not foreign matter is contained in the processing liquid based on the signal intensity of the emitted light;
an intensity information acquisition unit that acquires intensity information indicating the intensity of background light included in the emitted light based on the signal intensity;
a status monitoring unit that performs status monitoring based on the intensity information to monitor whether the type of the processing liquid is appropriate, whether the processing liquid has deteriorated, or whether other solutions have been mixed into the processing liquid, or to monitor the status of optical system hardware of the detection unit;
Equipped with
the irradiation light is irradiated onto the treatment liquid flow path from a direction intersecting a direction in which the treatment liquid flows in the treatment liquid flow path,
the emitted light received by the measurement unit is light emitted from the treatment liquid flow path in a direction different from a direction in which the irradiation light is irradiated,
the flow path forming portion includes a main body having the treatment liquid flow path formed therein, an inlet provided on one surface of the main body through which the treatment liquid flows into the main body, and an outlet provided on the one surface through which the treatment liquid flows out of the main body,
The foreign matter detecting device , wherein the emitted light received by the measuring unit is light emitted from the treatment liquid flow path in a direction opposite to a direction in which the one surface is located as viewed from the treatment liquid flow path . the foreign matter determining unit performs the determination based on the signal intensity obtained during a supply period from the start to the end of supply of the processing liquid to the substrate;
the foreign object determination unit makes the determination based on whether the signal strength is greater than a predetermined threshold value;
the intensity information acquisition unit acquires, as the intensity information, a time average of the signal intensity obtained during the same period as the supply period;
The foreign object detecting device according to claim 1 , wherein the state monitoring unit performs the state monitoring based on the intensity information acquired during the same period as the supply period. 3. The foreign object detecting device according to claim 1 , wherein the state monitoring unit monitors the state of the optical system hardware based on the intensity information in the state monitoring. a detection unit including a flow path forming unit that forms a processing liquid flow path through which a processing liquid supplied to a substrate flows, and a measurement unit configured to receive light emitted from the processing liquid flow path when light from a light source is irradiated onto the processing liquid flow path;
a foreign matter determining unit that determines whether or not foreign matter is contained in the processing liquid based on the signal intensity of the emitted light;
an intensity information acquisition unit that acquires intensity information indicating the intensity of background light included in the emitted light based on the signal intensity;
a status monitoring unit that monitors the status of optical system hardware of the detection unit based on the intensity information;
Equipped with
the irradiation light is irradiated onto the treatment liquid flow path from a direction intersecting a direction in which the treatment liquid flows in the treatment liquid flow path,
the emitted light received by the measurement unit is light emitted from the treatment liquid flow path in a direction different from a direction in which the irradiation light is irradiated,
The state monitoring unit monitors, as the state of the optical system hardware, a deviation of the optical axis of an optical system included in the optical system hardware. the measurement unit includes an irradiation unit configured to irradiate the treatment liquid flow path with the irradiation light, and a light receiving unit configured to receive the emitted light,
the light receiving unit includes a plurality of light receiving elements,
the intensity information acquisition unit acquires the intensity information for each light receiving position at which a light receiving element included in the plurality of light receiving elements is provided;
5. The foreign object detecting device according to claim 4 , wherein the state monitoring unit monitors deviation of the optical axis of the optical system based on the intensity information for each of the light receiving positions. a processing liquid supply unit having a nozzle that ejects a processing liquid toward a substrate and a supply unit that supplies the processing liquid to the nozzle;
a detection unit including a flow path forming unit that forms a treatment liquid flow path through which the treatment liquid flows, and a measurement unit configured to receive light emitted from the treatment liquid flow path when light from a light source is irradiated onto the treatment liquid flow path;
a foreign matter determining unit that determines whether or not foreign matter is contained in the processing liquid based on the signal intensity of the emitted light;
an intensity information acquisition unit that acquires intensity information indicating the intensity of background light included in the emitted light based on the signal intensity;
a status monitoring unit that performs status monitoring based on the intensity information to monitor whether the type of the processing liquid is appropriate, whether the processing liquid has deteriorated, or whether other solutions have been mixed into the processing liquid, or to monitor the status of optical system hardware of the detection unit;
Equipped with
the irradiation light is irradiated onto the treatment liquid flow path from a direction intersecting a direction in which the treatment liquid flows in the treatment liquid flow path,
the emitted light received by the measurement unit is light emitted from the treatment liquid flow path in a direction different from a direction in which the irradiation light is irradiated,
the flow path forming portion includes a main body having the treatment liquid flow path formed therein, an inlet provided on one surface of the main body through which the treatment liquid flows into the main body, and an outlet provided on the one surface through which the treatment liquid flows out of the main body,
In the substrate processing apparatus , the emitted light received by the measurement unit is light emitted from the processing liquid flow path in a direction opposite to a direction in which the one surface is located as viewed from the processing liquid flow path . a processing liquid supply unit having a nozzle that ejects a processing liquid toward a substrate and a supply unit that supplies the processing liquid to the nozzle;
a detection unit including a flow path forming unit that forms a treatment liquid flow path through which the treatment liquid flows, and a measurement unit configured to receive light emitted from the treatment liquid flow path when light from a light source is irradiated onto the treatment liquid flow path;
a foreign matter determining unit that determines whether or not foreign matter is contained in the processing liquid based on the signal intensity of the emitted light;
an intensity information acquisition unit that acquires intensity information indicating the intensity of background light included in the emitted light based on the signal intensity;
a status monitoring unit that monitors the status of optical system hardware of the detection unit based on the intensity information;
Equipped with
the irradiation light is irradiated onto the treatment liquid flow path from a direction intersecting a direction in which the treatment liquid flows in the treatment liquid flow path,
the emitted light received by the measurement unit is light emitted from the treatment liquid flow path in a direction different from a direction in which the irradiation light is irradiated,
The state monitoring unit monitors, as the state of the optical system hardware, a deviation of an optical axis of an optical system included in the optical system hardware. determining whether or not a foreign substance is contained in the processing liquid based on a signal intensity of light emitted from the processing liquid flow path when the processing liquid flow path through which the processing liquid to be supplied to the substrate flows is irradiated with light from a light source;
acquiring intensity information indicating the intensity of background light included in the emitted light based on the signal intensity;
and monitoring a state of optical system hardware of a detection unit having a measurement unit configured to receive the emitted light based on the intensity information;
the irradiation light is irradiated onto the treatment liquid flow path from a direction intersecting a direction in which the treatment liquid flows in the treatment liquid flow path,
the emitted light received by the measurement unit is light emitted from the treatment liquid flow path in a direction different from a direction in which the irradiation light is irradiated,
A foreign object detection method , wherein in monitoring the state of the optical system hardware, deviation of the optical axis of an optical system included in the optical system hardware is monitored as the state of the optical system hardware . A computer-readable storage medium storing a program for causing an apparatus to execute the foreign object detection method according to claim 8.