Liquid processing apparatus and monitoring method

Abstract

To monitor the status of multiple nozzles as appropriate for the situation.SOLUTION: A liquid processing apparatus includes a number of stages on which respective substrates are placed, and which are shared by the multiple stages for supplying processing liquid to the substrates, a camera shared by the multiple nozzles and monitoring the condition of the multiple nozzles, and an imaging condition changing unit that changes the imaging conditions of the camera in accordance with the monitoring conditions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to liquid treatment apparatus and monitoring methods. [Background technology]

[0002] In manufacturing semiconductor devices, a liquid processing apparatus includes a nozzle that ejects a processing liquid such as a resist from the nozzle onto a semiconductor wafer (hereinafter, referred to as a wafer) to form a resist film on the substrate. For example, Patent Document 1 discloses that a CCD camera is used to monitor the ejection state of the photoresist liquid from the processing liquid supply nozzle onto the substrate, and detects abnormalities in the ejection state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-318079 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques that allow the status of multiple nozzles to be monitored in a situational manner. [Means for solving the problem]

[0005] The liquid processing apparatus according to the present disclosure includes a plurality of stages on each of which a substrate is placed; a plurality of nozzles shared by the plurality of stages for supplying a processing liquid to the substrate; a camera shared by the plurality of nozzles for monitoring states of the plurality of nozzles; an imaging condition changing unit that changes the imaging conditions of the camera in accordance with a monitoring condition; Equipped with. Effect of the Invention

[0006] According to the present disclosure, the status of multiple nozzles can be monitored as appropriate to the situation. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a plan view showing the liquid treatment apparatus according to the embodiment. [Diagram 2] FIG. 2 is a vertical sectional side view showing the liquid treatment apparatus. [Diagram 3] FIG. 2 is a vertical sectional side view showing the liquid treatment apparatus. [Figure 4] FIG. 11 is a plan view showing a state in which the thinner nozzle has been moved to a discharge position. [Diagram 5] FIG. 4 is a plan view showing a state in which the resist nozzle has moved to a discharge position. [Figure 6] FIG. 11 is an explanatory diagram illustrating a schematic view of a focusing process. [Figure 7] FIG. 11 is an explanatory diagram illustrating a schematic view of a focusing process. [Figure 8] The image is focused on the thinner nozzle. [Figure 9] The image is focused on the resist nozzle. [Figure 10] 4 is a flowchart showing an operation of the liquid processing apparatus. [Figure 11] 13 is a graph showing the focus time ratio of a nozzle that does not eject treatment liquid. [Figure 12] FIG. 11 is a plan view showing a liquid processing apparatus according to a first modified example. [Figure 13] FIG. 11 is a plan view showing a liquid processing apparatus according to a second modified example. [Figure 14] FIG. 13 is a plan view showing a liquid processing apparatus according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] FIG. 1 is a plan view showing a resist coating apparatus which is an embodiment of the liquid processing apparatus of the present disclosure, and shows a state in which a nozzle 11, specifically a resist nozzle 11r, described later, is disposed at a discharge position described later. In this embodiment, an XYZ orthogonal coordinate system is used for explanation. In the resist coating apparatus, processing sections 21A and 21B are formed as places where the wafer W is processed. FIG. 2 is a vertical side view of the processing section 21A along the Y direction, and FIG. 3 is a vertical side view of the processing section 21A along the X direction. Hereinafter, the X direction may be referred to as the horizontal direction, and the Y direction may be referred to as the front-rear direction. In addition, the side where the processing liquid supply mechanism 10 including the nozzle 11 is disposed may be referred to as the front, and the side where the processing sections 21A and 21B on the opposite side are disposed may be referred to as the rear.

[0009] The resist coating apparatus is equipped with a processing liquid supply mechanism 10 that supplies thinner and resist as processing liquids to the wafer W in order to form a resist film on the wafer W. The thinner is supplied to the wafer W before the resist is supplied, and is a processing liquid for a process (pre-wetting) that enhances the wettability of the surface of the wafer W with respect to the resist.

[0010] The thinner is also used for EBR (Edge Bead Removal), which removes unnecessary portions of the resist film in a ring shape by being discharged onto the peripheral portion of the wafer W after the resist film is formed, and the thinner for EBR is supplied from EBR mechanisms 4A and 4B provided separately from the processing liquid supply mechanism 10. In this manner, in each of the processing sections 21A and 21B of the resist coating apparatus 1, the wafer W is processed in the order of pre-wetting, resist coating, and EBR.

[0011] The processing liquid supply mechanism 10 for performing pre-wetting and resist coating is shared by the processing sections 21A and 21B. In order to enable the control section 6 described later to monitor the state of each nozzle 11 constituting this processing liquid supply mechanism 10, the resist coating device is provided with a camera 31 for capturing an image of the nozzle 11, a plurality of lights, and a reflecting member 34 for reflecting the light emitted from some of the lights. The plurality of lights and the reflecting member 34 illuminate the nozzle 11 and the imaging area of ​​the camera 31 around it. As described later in detail, the light is irradiated from each light to the nozzle 11 via the surface of the wafer W. That is, the light emitted from the lights is reflected by the surface of the wafer W and is irradiated to the nozzle 11. The reflecting member 34 reflects the light from the lights toward the wafer W.

[0012] The processing units 21A and 21B will be described below. The processing units 21A and 21B are arranged side by side along the X direction, and the processing units 21A and 21B are sometimes collectively referred to as processing unit 21. Since the processing units 21A and 21B have the same configuration, the processing unit 21A will be described as a representative.

[0013] As shown in FIG. 2, the processing section 21A is provided with a cup 22A that is open at the top and that holds a wafer W in a holding area therein. In FIG. 2, reference numeral 23A denotes a drainage port provided in the cup 22A, and reference numeral 24A denotes an exhaust port for exhausting the inside of the cup 22A during processing of the wafer W. In the cup 22A, a spin chuck 25A is provided as a stage on which the wafer W is placed. The spin chuck 25A sucks the center of the back surface of the wafer W and holds the wafer W horizontally. The lower side of the spin chuck 25A is connected to a rotation drive unit 26. The rotation drive unit 26 rotates the spin chuck 25A together with the wafer W it holds around a vertical axis (Z axis). In the cup 22, three pins (only two pins are shown in FIG. 2) 28 that are raised and lowered by a lifting mechanism 27 are provided, and the wafer W is transferred between a transfer mechanism (not shown) for transferring the wafer W and the spin chuck 25A.

[0014] The processing section 21A is provided with a reflecting member 34A and an EBR mechanism 4A for performing EBR. The EBR mechanism 4A is disposed in an area to the left of the cup 22A. The EBR mechanism 4A includes a guide 41, a moving part 42, an arm 43, a peripheral nozzle 44A, and a cup-shaped standby part 45A. The moving part 42 moves linearly in the left-right direction (X direction) along the guide 41 on the front side of the cup 22A. In addition, an arm 43 that can be raised and lowered extends rearward from the moving part 42, and a peripheral nozzle 44A is provided at the rear end of the arm 43.

[0015] The peripheral nozzle 44A is connected to a thinner supply mechanism (not shown) via piping. The thinner supply mechanism supplies thinner to the peripheral nozzle 44A, which has been moved to a predetermined discharge position within the cup 22A, and the thinner is discharged downward. The thinner is discharged onto the peripheral portion of the wafer W that is being rotated by the spin chuck 25A, thereby performing EBR.

[0016] The standby section 45A is provided outside the cup 22A, and is located to the left of the center between the front and rear of the cup 22A. The moving section 42 moves the peripheral nozzle 44A between a standby position in the standby section 45A and a discharge position. When not in use, the peripheral nozzle 44A waits at the standby position. The standby section 45A is configured to store thinner therein and to discharge thinner from there, and the standby peripheral nozzle 44A is washed with the stored thinner at any time.

[0017] As shown in FIG. 1 and FIG. 2, the reflecting member 34A is disposed between the cup 22A and the EBR standby unit 45A. The reflecting member 34A is a vertical plate with two main surfaces facing the X direction in a plan view. The right main surface (the side facing the cup 22A) of the two main surfaces forms the reflecting surface 35A. The reflecting surface 35A is located above the cup 22A and can face the first illumination 32, which can be raised and lowered, in the horizontal direction, and is disposed so as to face slightly downward with respect to the horizontal direction. This allows the irradiation light from the first illumination 32 to be reflected toward the surface of the wafer W placed on the spin chuck 25A. As described above, the reflecting surface 35A is located on the opposite side to the side where the EBR standby unit 45A is located. Therefore, even if the thinner is splashed at the standby unit 45A, adhesion to the reflecting surface 35A is suppressed. Therefore, since the reflecting surface 35A is prevented from being contaminated, the clarity of the acquired imaging data is guaranteed.

[0018] As described above, processing section 21B is configured similarly to processing section 21A. Constituent members of processing section 21B that are the same as those of processing section 21A are designated by the same numerals as those used in processing section 21A. However, the alphabetical letters suffixed to the numerals are different between processing sections, and the alphabetical letters of processing section 21B are designated by the suffix B. Constituent members of processing sections 21A and 21B that are the same are collectively referred to by omitting the alphabetical letters, and may be designated by, for example, EBR mechanism 4, processing section 21, cup 22, spin chuck 25, reflecting member 34, reflecting surface 35, etc.

[0019] Between processing section 21A and processing section 21B, and on the front side thereof, a standby section 48 for each nozzle 11 constituting processing liquid supply mechanism 10 is provided. Standby section 48 is disposed behind cups 22A and 22B. As shown by the dashed line in FIG. 1, the detailed shape of this standby section 48 is omitted, but the standby section 48 is configured, for example, as a platform with a plurality of recesses (not shown) opening upward, and nozzles 11 are stored in the recesses and wait. The standby section 48 is configured to be able to supply thinner in the recesses and to drain the thinner. As a result, the outer surface of nozzle 11 during standby is supplied with thinner and cleaned.

[0020] The processing liquid supply mechanism 10 includes a plurality of nozzles 11 and a nozzle transport mechanism 15 which is a movable body for transporting the nozzles 11 onto each wafer W placed in each processing section 21, and supplies the processing liquid to the wafer W. The nozzle transport mechanism 15 includes a guide 16 which extends left and right on the front side of the waiting section 48, and an arm mechanism 17 which positions the nozzles 11 at a discharge position on each wafer W placed on the spin chuck 25.

[0021] As shown in FIGS. 1 and 2, the arm mechanism 17 includes a base end portion 18 and an arm 19 . The base end 18 has a lifting mechanism 18a that can move left and right along the guide 16, and a lifting unit 18b that is connected to the lifting mechanism 18a and raised and lowered. The base end of the lifting unit 18b is disposed on the left side of the lifting mechanism 18a, and the tip end extends rearward. The base end of an arm 19 that extends, for example, linearly in the horizontal direction is connected to the tip end of the lifting unit 18b so as to be rotatable around a rotation shaft 19a that extends along the Z axis. That is, the arm 19 rotates along a horizontal plane with the base end as the center.

[0022] Three nozzles 11 extending downward are attached to the lower part of the tip side of the arm 19. Of these nozzles 11, one resist nozzle 11r for discharging resist is arranged on the tip side of the arm 19, and two thinner nozzles 11t for discharging thinner are arranged on the base end side of the resist nozzle 11r. In this way, the resist nozzle 11r and the thinner nozzle 11t are arranged offset in the extension direction from the base end side to the tip side of the arm 19. The two thinner nozzles 11t are arranged side by side in a direction intersecting, specifically, perpendicular to, the extension direction of the arm 19. Note that one of the two thinner nozzles 11t is selected for use, and focusing of the thinner nozzle 11t, which will be described later, is performed so that the focus is on these two thinner nozzles 11t.

[0023] The resist nozzle 11r is connected to a resist supply mechanism 12 equipped with a valve and a pump, and the amount of resist supplied to the resist nozzle 11r is adjusted by the resist supply mechanism 12. That is, the amount of resist discharged from the resist nozzle 11r is adjusted by the resist supply mechanism 12. The thinner nozzle 11t is connected to a thinner supply mechanism 13 equipped with a valve and a pump, and the amount of resist supplied to the thinner nozzle 11t is adjusted by the thinner supply mechanism 13. That is, the amount of thinner discharged from the thinner nozzle 11t is adjusted by the thinner supply mechanism 13. The resist nozzle 11r and the thinner nozzle 11t as described above discharge the resist and the thinner downward at a discharge position in the cup 22 above the center of the wafer W held by the spin chuck 25.

[0024] 1 and 4 show the state where the resist nozzle 11r and thinner nozzle 11t have moved to the discharge positions in processing section 21A, respectively, and the arm 19 extends toward the right rear at these times. Note that the positional relationship between the arm 19 and processing section 21B when the resist nozzle 11r and thinner nozzle 11t have moved to the discharge positions in processing section 21B is the same as the positional relationship between the arm 19 and processing section 21A shown in FIGS. 1 and 4.

[0025] The resist coating apparatus 1 includes a camera 31 for monitoring the state of the nozzle 11, first and second illuminators 32 and 33, and the reflecting member 34 described above. As shown in FIG. 1 and FIG. 2, the first illuminator 32 is provided on the arm 19 at a lower portion closer to the base end than the nozzle 11. As the optical axis is illustrated by a dashed line, the first illuminator 32 irradiates light from the left side of the arm 19 (the left side when moving in the direction from the base end side to the tip end side of the arm 19). The first illuminator 32 is disposed at approximately the same height as the reflecting surface 35A of the reflecting member 34 so that the first illuminator 32 can irradiate light toward the left rear toward the reflecting surface 35A of the reflecting member 34 when each nozzle 11 is in the discharge position. The irradiated light along the optical axis from the first illuminator 32 is reflected by the reflecting surface 35A and the surface of the wafer W, and illuminates each nozzle 11 from the lower left.

[0026] The second illuminator 33 is provided on the front side of the right portion of the lifting mechanism 18a, and is disposed at a position higher than the cup 22. As shown by the dashed line, the optical axis of the second illuminator 33 is disposed so as to irradiate light slightly downward and rearward. This allows the second illuminator 33 to irradiate light from above the cup 22 toward the surface of the wafer W placed on the spin chuck 25. The second illuminator 33 is disposed in front of each nozzle 11 at the discharge position in a plan view, and the irradiation light from the second illuminator 33 directed toward the surface of the wafer W is reflected by the wafer W to illuminate each nozzle 11 from the lower rear.

[0027] Next, the camera 31 will be described. The camera 31 is attached to the arm 19 in a position and orientation such that the resist nozzle 11r and the two thinner nozzles 11t fit within its imaging range. More specifically, the camera 31 is supported by a connection part 31d provided so as to protrude from the tip of the arm 19 toward the tip side of the arm 19, and is provided in a region where the arm 19 is extended in a plan view, and imaging is performed from the tip side of the arm 19 toward the base end side.

[0028] FIG. 5 is a plan view for explaining the optical axis of the camera. The optical axes of the irradiated light from the reflecting member 34A and the second illumination 33 toward the nozzle 11 are located to the left and right with respect to the optical axis L1 of the camera 31. That is, when the camera 31 images each nozzle 11 and its surroundings, light is irradiated from the left and right to prevent the nozzle 11 from being shaded. In addition, the direction of the optical axis L1 of the camera 31 in a plan view is shifted from the direction of the straight line L2 indicating the extension direction of the arm 19. That is, in a plan view, the extension line of the optical axis L1 and the straight line L2 intersect with each other. This is intended to prevent each member, such as the lifting part 18b connected to the base end of the arm 19 and the second illumination 33 provided below the arm 19, from being reflected in the imaging range of the camera 31, and to increase the accuracy of the judgment when the abnormality is judged based on the imaging data D1. In addition, the optical axis L1 is slightly tilted downward with respect to the horizontal plane in order to include the lower side of the nozzle 11 in the imaging range.

[0029] However, since the camera 31 is provided on the arm 19 as described above, the distance of the resist nozzle 11r and the distance of the thinner nozzle 11t to the camera 31 are different from each other. The camera 31 is configured to change the focal length and focus on each of the resist nozzle 11r and the thinner nozzle 11t. This focusing will be described with reference to FIG. 3 and FIGS. 6 and 7 which show the focusing process. The camera 31 includes a housing 31a, an image sensor 31b and a variable focus lens 31c housed in the housing 31a, and is connected to an external power source 30. Light passing through the variable focus lens 31c forms an image on the image sensor 31b. The image sensor 31b photoelectrically converts the received light to generate imaging data D1, and transmits the imaging data D1 to the control unit 6 described later.

[0030] The variable-focus lens 31c is an interface between two types of liquids 30a and 30b that are separated from each other and sealed in the lens unit 31g. As shown in Figs. 6 and 7, the focal length of the camera 31 changes as the shape of the interface between the liquids 30a and 30b changes due to a change in the voltage applied from the external power source 30 to the electrode 31e provided in the lens unit 31g. That is, the lens unit 31g is configured as a liquid lens. In the figure, 31f is an insulating member that insulates the electrodes 31e from each other.

[0031] 6 and 7, of the resist nozzle 11r and the thinner nozzle 11t, the nozzles that are focused are indicated by solid lines, and the nozzles that are not focused are indicated by dotted lines. In the following explanation, the state in which the focus is on the thinner nozzle 11t as in Fig. 6 may be referred to as a first focus state, and the state in which the focus is on the resist nozzle 11r as in Fig. 7 may be referred to as a second focus state.

[0032] Incidentally, the imaging area of ​​the camera 31 includes not only the nozzle 11 but also the periphery of the nozzle 11. More specifically, this periphery includes the area below the nozzle 11. Therefore, it is possible to image in focus the liquid column P1 of the processing liquid formed by the focused nozzle 11 and the droplets P2 of the processing liquid dripping from the nozzle 11. The liquid column P1 and the droplets P2 will be described in more detail later.

[0033] The camera 31 configured as described above repeatedly captures images of the resist nozzle 11r and the thinner nozzle 11t within the imaging range by alternately focusing on them without moving the imaging range. In other words, with the relative positions of the resist nozzle 11r, the thinner nozzle 11t, and the camera 31 fixed, the first focus state and the second focus state are repeatedly switched to acquire imaging data D1 of each nozzle 11, thereby monitoring these nozzles 11. Note that Figs. 4 and 6 show how each nozzle 11 is monitored when the thinner nozzle 11t is used to process the wafer W in step S2 described later.

[0034] FIG. 8 is an example of imaging data when the camera focuses on the thinner nozzle and captures an image (first focus state in FIG. 6), and FIG. 9 is an example of imaging data when the camera focuses on the resist nozzle and captures an image (second focus state in FIG. 7). Switching between the first focus state and the second focus state can be performed, for example, in 100 ms or less. The reason why the camera 31 is configured to include a liquid lens is that the shape of the lens changes instantly when a voltage is applied (i.e., the focus is adjusted). More specifically, this is because it is possible to switch the focus in an extremely short time, as shown in the example, compared to a configuration in which the focus is adjusted by changing the positional relationship of each member constituting the optical system.

[0035] Hereinafter, the imaging data captured with the focus on the resist nozzle 11r and the imaging data captured with the focus on the thinner nozzle 11t may be simply referred to as imaging data of the resist nozzle 11r and imaging data of the thinner nozzle 11t. In addition, the nozzle 11 being imaged in the imaging data refers to the resist nozzle 11r or the thinner nozzle 11t that is imaged relatively clearly by focus adjustment.

[0036] The resist coating apparatus 1 includes a control unit 6 which is a computer (see FIG. 1). The control unit 6 includes a program storage unit for controlling the operation of each part of the resist coating apparatus 1, a memory, and an alarm output unit. The program storage unit stores a program in which commands (steps) for operating each part of the apparatus to form a resist film on the wafer W, as described below. The program storage unit is a storage medium such as a hard disk, a compact disk, a magnetic optical disk, a memory card, or a DVD. The program causes the control unit 6 to output control signals to each part of the resist coating apparatus 1, thereby forming the resist film.

[0037] This program also switches the lighting used between the processing units 21A and 21B, acquires the imaging data D1 by the camera 31, switches the focus of the camera 31, and determines whether or not there is an abnormality in the resist nozzle 11r and the thinner nozzle 11t based on the imaging data D1. That is, this program monitors the nozzle 11 and serves as an imaging condition changing unit that changes the imaging conditions according to the monitoring conditions. Furthermore, the program also controls countermeasures such as alarm output that are performed in conjunction with the monitoring.

[0038] The monitoring of the nozzles 11 will be described in more detail. When one of the resist nozzle 11r and the thinner nozzle 11t moves to a discharge position above the center of the wafer W to discharge the processing liquid (resist or thinner), the other also moves to a position slightly off the discharge position (for convenience of explanation, this is referred to as a retreat position) (see FIGS. 1 and 4). When either of the nozzles 11 is positioned at the discharge position, imaging data D1 is acquired. At this time, by switching the focus, both the resist nozzle 11r and the thinner nozzle 11t are repeatedly imaged.

[0039] For the nozzle 11 that discharges the treatment liquid at the discharge position, whether or not the discharge state of this treatment liquid is appropriate is judged from the image data D1, and the presence or absence of an abnormality is judged. The discharge of the treatment liquid forms a liquid column P1 of the treatment liquid below the nozzle 11, and whether or not the discharge state of the treatment liquid is appropriate includes factors such as whether or not this liquid column P1 is formed at an appropriate timing and whether or not the shape of the liquid column P1 is appropriate (whether the thickness is appropriate and there is no distortion).

[0040] For the nozzle 11 at the retracted position, the presence or absence of an abnormality other than the discharge state of the processing liquid is determined from the imaging data D1. Specifically, for example, the falling (dripping) of droplets P2 from the nozzle 11 and the amount of thinner used in cleaning the nozzle 11 attached to the outer surface of the nozzle 11 are determined from the image. Note that the dripping droplets P2 are the processing liquid or thinner used in cleaning and attached to the nozzle 11. Furthermore, when managing the liquid level position of the processing liquid in the nozzle 11 at the retracted position, it may be determined from the imaging data D1 whether the liquid level position is within an allowable range.

[0041] The resist nozzle 11r and the thinner nozzle 11t are provided close to each other by being provided on the same arm 19, and while one nozzle 11 is located at the discharge position, the other nozzle 11 is located at the retreat position, but this retreat position is also above the wafer W, just like the discharge position. Therefore, if the processing liquid or the thinner used in cleaning falls from the nozzle 11 as described above, it may be supplied onto the wafer W and cause an abnormality. Also, if there is an abnormality in the discharge state of the processing liquid of the nozzle 11 at the discharge position, it may cause an abnormality such as an appropriate amount of processing liquid not being supplied to the wafer W or the processing liquid being splashed on the wafer W and becoming a foreign object. Since there is a risk of a malfunction occurring in the processing of the wafer W due to an abnormality of each nozzle 11 at the discharge position or the retreat position, the focus of the camera 31 is repeatedly switched at high speed, image data D1 of each nozzle 11 at the discharge position or the retreat position is repeatedly acquired, and an abnormality is judged based on each image data D1.

[0042] The presence or absence of an abnormality is determined, for example, by storing reference data of the nozzle 11 captured in an abnormal-free state in the memory of the control unit 6, and having the program compare this reference data with the acquired captured image data D1. If it is determined that an abnormality exists, an alarm is output from the alarm output unit 65 using a predetermined sound or image.

[0043] The operation of the resist coating apparatus will be described step by step with reference to the flow chart of FIG. 10. First, for example, the wafer W is transported to 21A of the processing sections 21A and 21B and is held by suction on the spin chuck 25. The thinner nozzle 11t and the resist nozzle 11r waiting in the waiting section 48 move to a discharge position and a retreat position on the wafer W, respectively, and the first illumination 32 and the second illumination 33 of the processing section 21A emit light to illuminate the thinner nozzle 11t and the resist nozzle 11r (step S1). Then, the camera 31 captures an image and repeatedly switches the focus, and image data D1 of the thinner nozzle 11t and the resist nozzle 11r are repeatedly acquired.

[0044] In parallel with the acquisition of the imaging data D1 of the nozzle 11, thinner is discharged from the thinner nozzle 11t to form a liquid column P1. From the imaging data acquired for the thinner nozzle 11t, the presence or absence of an abnormality in the thinner discharge state from the thinner nozzle 11t is determined. Also, from the imaging data D1 acquired for the resist nozzle 11r, the presence or absence of an abnormality other than the resist discharge state from the resist nozzle 11r (dripping of droplets P2, amount of cleaning thinner adhering to the nozzle outer surface) is determined (step S2).

[0045] The thinner nozzle 11t stops discharging the thinner, and the acquisition of the image data D1, the switching of the focus, and the determination of the presence or absence of anomalies are temporarily stopped. The thinner supplied to the center of the wafer W is applied to the entire surface by the rotation of the wafer W, and pre-wetting is performed. Meanwhile, the arm 19 moves left and right and turns to move the resist nozzle 11r to the discharging position on the wafer W where the pre-wet was performed in step S1, and the thinner nozzle 11t moves to the retreated position (step S3).

[0046] The acquisition of imaging data and the switching of focus are resumed, and imaging data D1 of the thinner nozzle 11t and the resist nozzle 11r are repeatedly acquired. In parallel with the acquisition of imaging data of the nozzle 11, resist is discharged from the resist nozzle 11r to form a liquid column P1. From the imaging data acquired for the resist nozzle 11r, the presence or absence of an abnormality in the discharge state of the resist from the resist nozzle 11r (dripping of droplets P2, the amount of cleaning thinner adhering to the nozzle outer surface) is determined. Also, from the imaging data acquired for the thinner nozzle 11t, the presence or absence of an abnormality other than the thinner discharge state from the thinner nozzle 11t is determined (step S4). Therefore, the abnormality is determined in the same manner as in step S2.

[0047] The discharge of resist from the resist nozzle 11r stops, and the acquisition of image data D1, the switching of focus, the determination of the presence or absence of abnormalities, and the light irradiation from the first illumination 32 and the second illumination 33 stop. The resist supplied to the center of the wafer W by the rotation of the wafer W is applied to the entire surface to form a resist film. The peripheral nozzle 44 moves from the waiting section 45A to the discharge position, thinner is discharged to perform EBR, and then the wafer W is carried out from the processing section 21A.

[0048] While the wafer W is being processed in the processing section 21A, the wafer W is transferred to the processing section 21B. When the discharge of the resist in the processing section 21A is completed, the resist nozzle 11r and the thinner nozzle 11t move to the processing section 21B, where the wafer W is processed in the same procedure as the processing in the processing section 21A, and during this processing, the presence or absence of an abnormality of the nozzle 11 is determined. Thereafter, the wafer W is transferred alternately and repeatedly to the processing sections 21A and 21B, where processing and abnormality determination are performed. If an abnormality is determined in steps S2 and S4 of the processing sections 21A and 21B, an alarm is output. In addition to outputting the alarm, the processing of the wafer W may be stopped at the time when an abnormality is determined, and the resist nozzle 11r and the thinner nozzle 11t may be returned to the standby section 48, and each nozzle 11 may be cleaned.

[0049] In each of steps S2 and S4, the discharge start time of the processing liquid (resist or thinner) onto the wafer W is t1, the discharge end time is t3, and the period from time t1 to t3 is the processing liquid discharge period T1. When switching the focus as described above, the ratio of the focus time per unit time for each nozzle 11 may be varied during the processing liquid discharge period T1.

[0050] 11, which shows the focus time ratio of the nozzles 11 that do not discharge the processing liquid (i.e., the resist nozzle 11r in step S2 and the thinner nozzle 11t in step S4, which detect abnormalities such as dripping). From time t1 when the processing liquid starts to be discharged until immediately thereafter (shown as time t2 in the graph), the movement of the processing liquid toward the nozzle 11 is unstable compared to time t2 and thereafter, and there is a risk that the shape of the liquid column P1 formed below the nozzle 11 will also become unstable. Therefore, from time t1 to t2, the ratio of the focus time per unit time on the nozzle 11 that discharges the processing liquid and forms the liquid column P1 is relatively large compared to time t2 to t3, and the ratio of the focus time per unit time on the nozzle 11 that does not discharge the processing liquid is relatively small.

[0051] To give a more specific example, when the focus change is repeated in step S2, the resist nozzle 11r is focused and then continues to be focused until time t11 has elapsed. Then, the thinner nozzle 11t is focused from time t1 to t2 and then continues to be focused until time t11+α has elapsed, and from time t2 to t3, the thinner nozzle 11t is focused and then continues to be focused until time t11 has elapsed. In this way, the thinner liquid column P1 is imaged and monitored for a longer period from time t1 to t2 compared to time t2 to t3, thereby increasing the accuracy of detecting abnormalities in the liquid column P1.

[0052] It should be noted that the camera 31 transmits the imaging data D1 at regular intervals to the control unit 6. Therefore, if the proportion of the focus time per unit time of the nozzle 11 that does not eject the treatment liquid from time t1 to t2 is small, this means that the frequency of acquiring the imaging data D1 per unit time of the nozzle 11 is low.

[0053] As described above, according to the resist coating apparatus, the camera 31 captures images under imaging conditions selected from a plurality of imaging conditions according to the monitoring conditions of the nozzle 11. That is, the imaging conditions are selected such that either the first focus state for the thinner nozzle 11t or the second focus state for the resist nozzle 11r is selected according to the monitoring conditions of which of the thinner nozzle 11t and the resist nozzle 11r is to be monitored. Then, depending on the monitoring conditions of which of the monitoring of the nozzle 11 during processing of the wafer W in the processing section 21A and the monitoring of the nozzle 11 during processing of the wafer W in the processing section 21B is to be performed, the use of the first illumination 32, the second illumination 33, and the reflecting member 34A and the use of the first illumination 32, the second illumination 33, and the reflecting member 34B are switched. That is, the members to be used are selected as the imaging conditions. Therefore, in the resist coating apparatus, the monitoring of each nozzle 11 can be performed with high accuracy, and the accuracy of the judgment of the presence or absence of an abnormality can be increased.

[0054] In addition, as described above, each of the nozzle 11 at the discharge position and the nozzle 11 at the retreated position may cause an abnormality in the processing of the wafer W. Therefore, monitoring both of these nozzles 11 to detect abnormalities is effective in preventing a decrease in the yield of semiconductor products. In monitoring both the thinner nozzle 11t and the resist nozzle 11r in this way, using a common camera 31 by switching the focus reduces the number of cameras 31 installed, which is preferable in terms of preventing the device from becoming larger and the cost from increasing. Note that, as described above, it is preferable for the camera 31 to be equipped with a liquid lens because of the speed of switching the focus, but a configuration without a liquid lens is also possible.

[0055] Incidentally, when changing the imaging conditions according to the monitoring conditions, the imaging conditions may be the illuminance by the first illumination 32 and the second illumination 33, or a threshold value for determining an abnormality in the imaging data D1. For example, it is assumed that illumination other than the first illumination 32 and the second illumination 33 is provided in the apparatus, and there is variation in the illuminance by the illumination between the processing sections 21A and 21B. In that case, in order to compensate for the variation in the illuminance by the illumination, for example, a difference may be formed between the illuminance of the light irradiated from the first illumination 32 and the second illumination 33 in the processing section 21A toward the wafer W and the illuminance of the light irradiated from the first illumination 32 and the second illumination 33 in the processing section 21B toward the wafer W.

[0056] An example of changing the threshold value for determining anomaly of the imaging data D1 will also be given. The imaging data D1 acquired by the camera 31 is data having brightness information for each pixel, for example. In determining whether the droplet P2 has dripped or not, the position of the nozzle 11 is specified in the imaging data D1. Then, when a group of pixels each exceeding a predetermined brightness threshold appears below the nozzle 11 and the group is formed by a number of pixels within a predetermined range, it is determined that the droplet P2 has dripped. The brightness threshold value may be different when processing the wafer W in the processing section 21A and when processing the wafer W in the processing section 21B. For example, it is considered that the structure of the device reflected in the area outside the nozzle 11 is different when the nozzle 11 is imaged in the processing section 21A and when the nozzle 11 is imaged in the processing section 21B. By making the brightness threshold value different when determining anomaly based on the data imaged in the processing section 21A and when determining anomaly based on the data imaged in the processing section 21B, the influence of the difference in the reflected structure on the determination of anomaly can be suppressed.

[0057] In this embodiment, during the period T1 during which the treatment liquid is discharged from the nozzle 11, the focus is repeatedly switched and the imaging data D1 is acquired each time the focus is switched, but the imaging data D1 may be acquired by repeatedly switching the focus only during a part of the period T1. In addition, the presence or absence of an abnormality may be determined from the imaging data D1 at any timing.

[0058] Machine learning may be used to determine whether or not there is an abnormality in the nozzle 11. For example, before processing the wafer W, a large amount of image data acquired by the camera 31 for each of the nozzles 11r and 11t is stored in advance in the memory of the control unit 6. This large amount of image data includes image data acquired when dripping occurs and image data acquired when there is no abnormality, and each image data is stored in association with information indicating that dripping has occurred or that the nozzle is normal. In other words, learning about dripping is performed.

[0059] Then, in steps S2 and S4 during the processing of the wafer W, when the imaging data D1 of the nozzle 11 that does not discharge the processing liquid is acquired, the imaging data that is most similar to the imaging data D1 acquired during this processing is selected from a large number of imaging data stored in the memory of the control unit 6. Then, according to the information associated with the selected imaging data, it is determined whether dripping has occurred or there is no abnormality. By this determination using machine learning, it is possible to accurately determine the presence or absence of an abnormality even when, for example, the amount of light irradiated from each illumination to the nozzle 11 is relatively small or when the imaging data D1 shows a component of the device in the outer area of ​​the nozzle 11. In addition, from the stored imaging data in which dripping has occurred, predicted imaging data in which dripping has occurred may be generated by a predetermined algorithm. In this case, it is also possible to determine that dripping has occurred when the actual imaging data D1 matches the predicted imaging data.

[0060] The present disclosure can also be used for managing the liquid level position of the processing liquid in the nozzle 11 and detecting defects in the nozzle 11 itself, as described above. In this case, machine learning may also be used to identify a background object located behind the nozzle 11 in the imaging data in the region near the outline of the nozzle 11 or the liquid level in the nozzle 11 as something different from the nozzle 11 or its liquid level. Examples of background objects include a coating pattern formed on the surface of a substrate and a structure that constitutes a processing device. If this background object is located near the nozzle 11, it is difficult to determine and detect the nozzle shape and the liquid level. By such identification, the shape of the nozzle 11 and the liquid level can be correctly recognized in the imaging data, making it easier to determine the presence or absence of nozzle damage such as dirt, scratches, and deformation of the nozzle 11, and abnormalities such as dripping.

[0061] Furthermore, nozzle damage including the tip of the nozzle 11 may be determined or detected based on both the state of the area corresponding to the nozzle 11 in the imaging data and the width of the liquid column of the processing liquid discharged from the nozzle 11. When imaging data is obtained by imaging the nozzle 11 from the side, depending on the imaging direction (optical axis L1), the tip surface and the side surface of the nozzle 11 are in an overlapping area in the imaging data D1, making it difficult to identify the location of the nozzle damage to be detected in that area. In this case, for example, if the width of the liquid column of the processing liquid discharged from the nozzle 11 is abnormal, it can be determined that the nozzle damage is located at the tip of the nozzle 11 by assuming that the nozzle damage at the tip of the nozzle 11 including the discharge port of the processing liquid is related to the abnormality in the width of the liquid column. In other words, even when imaging the nozzle 11 from the side direction where it is difficult to identify the tip of the nozzle 11, the presence or absence of nozzle damage at the tip of the nozzle 11 can be determined.

[0062] Abnormalities other than dripping can also be learned in the same manner as above, and the presence or absence of an abnormality can be determined based on that learning when processing the wafer W. For example, machine learning may also be used to determine the presence or absence of an abnormality in the shape of the liquid column formed by the ejection of the processing liquid. Although it may be difficult to grasp the shape of the liquid column in the image data D1 of the nozzle 11 when the liquid column is formed due to scattering of light irradiated to the wafer W, even in such a case, the use of machine learning makes it possible to accurately determine an abnormality in the shape of the liquid column. Note that the determination of the presence or absence of an abnormality by machine learning may be made using deep learning.

[0063] Machine learning is not limited to use only for determining the presence or absence of anomalies, but can also be used for adjusting the focus of the camera 31. When the camera 31 or the nozzle 11 is removed from the arm 19 for maintenance and then reattached, the focus is shifted due to slight errors in each part, so the user of the device manually adjusts the focus. This adjustment is performed by changing the voltage applied to the electrode 31e of the lens unit 31g from the external power source 30 to change the shape of the focus variable lens 31c while acquiring image data. After the focus adjustment, for example, the maximum and minimum values ​​of the brightness of the image data of the nozzle 11 acquired before focus correction (initially after each component is reattached) are associated with the applied voltage after the focus adjustment and stored in the control unit 6. When a large number of such correspondence data between the maximum and minimum values ​​of the brightness and the applied voltage are stored, the focus is automatically adjusted based on this correspondence data. Specifically, when the image data of the nozzle 11 is acquired after each component is reattached, the control unit 6 calculates the maximum and minimum values ​​of the brightness of the image data, selects the value closest to the calculated value from the stored correspondence data, and corrects the applied voltage so that it becomes the applied voltage of the corresponding data.

[0064] Incidentally, the presence of a droplet P2 that will drip is determined by whether the brightness of a group of pixels exceeds a predetermined threshold value, and this threshold value will be further described. Before processing the wafer W, imaging data of the nozzle 11 is acquired in advance, and the average brightness value of each pixel is calculated. This average brightness value is associated with the above threshold value and stored. The threshold value for this average value is set to a relatively low value within a range in which it is possible to determine that the droplet is present. Then, the average brightness value of the imaging data is changed by irradiating light around the nozzle 11 or arranging a structure. A threshold value of a relatively low value is set for the average brightness value thus changed, and these are stored in association with each other. Correspondence data between the average brightness value and the threshold value is repeatedly acquired in this manner. When processing the wafer W, the average brightness value is acquired from the acquired imaging data, and the threshold value of the corresponding data that is closest to the average brightness value among the stored corresponding data is used to determine dripping.

[0065] Incidentally, the presence or absence of the formation of the liquid column P1 is determined in the same manner as the presence or absence of the dripping droplet P2, so the threshold value may be determined to be a relatively low value according to the actually acquired imaging data, as in the case of the dripping droplet P2. If other structures are reflected around the nozzle 11 in the imaging data, the average brightness value becomes relatively high, and if the threshold value is low, there is a risk of the other structures being erroneously detected as droplets P2 or liquid column P1. However, if the average brightness value is low, that is, if the reflection of other structures is suppressed, this erroneous detection can be suppressed, so a relatively low threshold value is set based on the corresponding data stored in advance as described above. This increases the detection sensitivity of the dripping droplets P2 and liquid column P1.

[0066] Modifications of the illumination and the reflecting member will be described below. Fig. 12 is a plan view showing a first modification. In the first modification, the reflecting members 34A and 34B may be disposed to the right of the cups 22, the first illumination 32 may be disposed to the right of the arm 19, and the second illumination 33 may be disposed to the left of the lifting mechanism 18a. In this case, the first illumination 32 and the second illumination 33 irradiate light onto the nozzle 11 from the opposite left and right sides of this embodiment.

[0067] In this first modified example and this embodiment, the first illuminator 32 is provided on the arm 19, and the second illuminator 33 is provided on the lifting mechanism 18a, but this is not an essential requirement. For example, the first illuminator 32 may be disposed outside and above each cup 22, similar to the second illuminator 33. Also, for example, the second illuminator 33 may be provided on the arm 19, and two sets of reflecting members 34 may be provided for each processing section 21. In either case, it is preferable that the first illuminator 32 and the second illuminator 33 are disposed so as to illuminate the nozzle 11 from both the left and right sides.

[0068] In the second modification shown in FIG. 13, the first illuminator 32 is not provided on the arm 19, and the reflecting member 34 is not provided. In this modification, the fourth illuminator 37 and the fifth illuminator 38 are provided corresponding to each cup 22. Specifically, the fourth illuminator 37 and the fifth illuminator 38 are arranged on the left side of the cup 22A so as to irradiate the nozzle 11 on the wafer W in each cup 22 with light from the left side. The fourth illuminator 37 is arranged so as to irradiate the nozzle 11 from the side during discharge in the cup 22A. The fifth illuminator 38 is arranged so as to irradiate the nozzle 11 from a little behind during discharge in the cup 22B, and is arranged so that the optical axis does not pass through the center of the cup 22A and the cup 22B in a plan view.

[0069] 14, the fourth illuminator 37 and the fifth illuminator 38 in the second modified example are arranged left-right reversely. Therefore, the fourth illuminator 37 and the fifth illuminator 38 are arranged on the right side of the cup 22B so as to irradiate the nozzles 11 on each cup 22 with light from the right side. As exemplified above, the configuration and arrangement of the illumination in the present disclosure can be arbitrarily set.

[0070] The number of processing sections 21 is not limited to two, and may be more than two. For example, processing section 21 may be configured to have three processing sections 21 by providing processing section 21C in addition to processing sections 21A and 21B, and these processing sections 21A to 21C may be arranged in a straight line in the left-right direction, and processing liquid supply mechanism 10 may be configured to be shared by the three processing sections 21. Even when processing section 21C is provided in this manner, the arrangement of reflecting member 34 and lighting may be applied to the arrangements of each of the above-mentioned examples. That is, when reflecting member 34 and first lighting 32 are provided for each processing section 21, cup 22, reflecting member 34, and first lighting 32 may be provided in processing section 21C in the same layout as cup 22, reflecting member 34, and first lighting 32 in processing sections 21A and 21B. Although an example in which lighting is arranged to be shared by processing section 21 has been shown, it may be shared by processing sections 21A to 21C.

[0071] The liquid processing apparatus to which the present technology is applied is not limited to a resist coating apparatus. For example, instead of resist, a chemical solution for forming an anti-reflection film or a chemical solution for forming an insulating film may be discharged from the nozzle 11r. The present technology can also be applied to a liquid processing apparatus provided with a nozzle for supplying a developer to the resist film after exposure on the arm 19 for development, and a nozzle for supplying a cleaning liquid such as pure water to clean the surface of the wafer W after supplying the developer. Furthermore, in each embodiment, the substrate to be processed is not limited to a wafer, but may be, for example, a substrate for manufacturing a flat panel display or a mask substrate for manufacturing a mask for exposure. Therefore, a rectangular substrate may be processed.

[0072] It should be noted that the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, modified, and combined in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0073] 11r Resist nozzle 11t thinner nozzle 25A, 25B Spin Chuck 31 Camera 6. Control Unit W wafer

Claims

1. a plurality of stages on each of which a substrate is placed; a plurality of nozzles shared by the plurality of stages for supplying a processing liquid to the substrate; a camera shared by the plurality of nozzles for monitoring states of the plurality of nozzles; an imaging condition changing unit that changes the imaging conditions of the camera in accordance with a monitoring condition; A liquid treatment device comprising:

2. a movable body having the plurality of nozzles and movable relative to each stage to supply the processing liquid to the substrate on each stage; a light provided on the movable body and configured to irradiate light in a direction different from a direction toward each of the nozzles; a reflecting member whose position relative to the stage is fixed and which reflects the light emitted from the illumination and irradiates the light onto each of the nozzles; The liquid treatment device of claim 1 , comprising:

3. The liquid treatment apparatus according to claim 2 , wherein the reflecting member reflects the irradiated light from the illumination toward the substrate on the stage, and the light reflected from the substrate is irradiated onto each of the nozzles.

4. The liquid treatment apparatus according to claim 2 , wherein the reflecting member is provided for each of the stages.

5. the camera has a liquid lens and is disposed so that the plurality of nozzles are within an imaging range of the camera; The liquid processing apparatus according to claim 1 , wherein the imaging condition change unit monitors the states of the plurality of nozzles by changing a focus depending on the nozzle to be monitored.

6. The change in focus monitoring a discharge state of the treatment liquid from one of the nozzles; and The liquid processing apparatus according to claim 5 , wherein monitoring of a state other than the ejection state of the other nozzles is performed alternately.

7. a plurality of nozzles are provided, and an arm is provided that moves relative to each stage to supply the processing liquid to the substrate on each stage; The liquid treatment apparatus according to claim 1 , wherein the camera is provided on the arm such that an optical axis of the camera is oriented in a direction different from a direction in which the arm extends in a plan view.

8. placing substrates on a plurality of stages; supplying a processing liquid to the substrate by a plurality of nozzles shared by the plurality of stages; a monitoring step of capturing an image of each of the nozzles using a camera shared by the plurality of nozzles and monitoring the states of the plurality of nozzles; changing the imaging conditions of the camera in accordance with the monitoring conditions; A monitoring method including:

9. the camera having a liquid lens; taking an image of the plurality of nozzles within an imaging range of the camera; The monitoring method according to claim 8 , wherein the monitoring step includes a step of monitoring the states of the plurality of nozzles by changing a focus depending on the nozzle to be monitored.

Images