Liquid processing apparatus and liquid detection method for liquid processing apparatus

Abstract

The present application provides a liquid processing apparatus and a liquid detection method for a liquid processing apparatus. The liquid processing apparatus includes: a placement portion capable of placing a substrate; a nozzle for supplying a processing liquid to the substrate placed on the placement portion to perform processing; a photographing portion for photographing the nozzle to obtain image data; and a detection portion for detecting a liquid surface based on a plurality of the image data obtained at different times from each other during a period in which the processing liquid is not supplied from the nozzle, the liquid surface being formed by the processing liquid or a liquid other than the processing liquid provided in a flow path of the processing liquid in the nozzle. The present application can reliably prevent processing abnormalities when performing liquid processing on a substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid processing apparatus and a liquid detection method for a liquid processing apparatus. BACKGROUND

[0002] In a manufacturing process of a semiconductor device, a semiconductor wafer (hereinafter referred to as a wafer) as a substrate is subjected to various processing liquids such as resist and the like from a nozzle to perform processing. In Patent Literature 1, a technique is described in which a nozzle is repeatedly photographed by a photographing section, data of a foreign matter present in a discharge port portion of the nozzle is acquired, and it is determined whether or not there is an abnormality. As the foreign matter, a liquid, a solid substance, or a defect is described.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2015-153903 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The present application provides a technique capable of reliably preventing processing from becoming abnormal when a substrate is subjected to liquid processing.

[0008] TECHNICAL SOLUTION FOR SOLVING THE PROBLEMS

[0009] The liquid processing apparatus of the present application includes: a placement section capable of placing a substrate; a nozzle for supplying a processing liquid to the substrate placed on the placement section to perform processing; a photographing section for photographing the nozzle to acquire image data; and a detection section for detecting a liquid surface based on a plurality of the image data obtained at different times from each other during a period in which the processing liquid is not supplied from the nozzle, the liquid surface being formed by the processing liquid or a liquid other than the processing liquid provided in a flow path of the processing liquid in the nozzle.

[0010] EFFECTS OF THE INVENTION

[0011] According to the present application, it is possible to reliably prevent processing from becoming abnormal when a substrate is subjected to liquid processing. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a perspective view of an embodiment of the liquid processing apparatus of the present application, that is, a resist film forming apparatus.

[0013] Figure 2 is a longitudinal sectional side view of the resist film forming apparatus.

[0014] Figure 3is a longitudinal sectional side view of a nozzle and a pipe provided in the resist film forming apparatus described above.

[0015] Figure 4 is a side view of the nozzle described above.

[0016] Figure 5 is a schematic view of image data obtained by photographing the nozzle described above.

[0017] Figure 6 is a side view of the nozzle described above.

[0018] Figure 7 is a schematic view of image data obtained by photographing the nozzle described above.

[0019] Figure 8 is a schematic view showing an example of reference data of the nozzle described above.

[0020] Figure 9 is an explanatory view showing processing of the image data described above.

[0021] Figure 10 is an explanatory view showing processing of the image data described above.

[0022] Figure 11 is a flowchart for detecting an abnormality of the nozzle described above.

[0023] Figure 12 is a flowchart for detecting an abnormality of the nozzle described above.

[0024] BRIEF DESCRIPTION OF REFERENCE NUMERALS

[0025] W wafer

[0026] 1 resist film forming apparatus

[0027] 11 rotary chuck

[0028] 36 camera

[0029] 41 nozzle

[0030] 42 flow path

[0031] 44 pump

[0032] 65 liquid surface

[0033] 7 control section DETAILED DESCRIPTION

[0034] Reference Figure 1 perspective view and Figure 2A longitudinal sectional side view of an embodiment of the liquid processing apparatus of the present application, i.e., a resist film forming apparatus 1, is shown. The resist film forming apparatus 1 supplies a wafer W with a resist as a processing liquid, applies the resist by spin coating, and forms a resist film.

[0035] A rotary chuck 11 that is a placement portion for placing the wafer W is shown in the figure. The rotary chuck 11 adsorbs the back central portion of the wafer W and holds the wafer W horizontally. Figure 2 A rotary mechanism 12 is connected to the rotary chuck 11 via a vertical shaft portion 13. The rotary mechanism 12 rotates the rotary chuck 11 to rotate the wafer W held by the rotary chuck 11 around the central axis.

[0036] A cup-shaped body 21 is shown in the figure, which is disposed so as to surround the wafer W held by the rotary chuck 11 to receive the drain liquid scattered or dropped from the rotating wafer W. Figure 2 A drain port 22 is shown in the figure, which is opened in the bottom of the cup-shaped body 21. Figure 2 A gas exhaust pipe 23 is shown in the figure, which is disposed so as to stand from the bottom of the cup-shaped body 21, and exhausts the cup-shaped body 21 during processing of the wafer W in the resist film forming apparatus 1. Three vertical lift pins (only two are shown) 24 are shown in the figure, which are disposed at intervals in the rotation direction of the wafer W, are vertically lifted by a lift mechanism 25, and perform the handover of the wafer W between an unshown conveyance mechanism and the rotary chuck 11. Figure 2

[0037] A moving portion 31 is shown in the figure, which is disposed outside the cup-shaped body 21 and is capable of horizontal movement along a guide 32. A work arm 33 is horizontally extended from the moving portion 31 in a direction orthogonal to the moving direction of the moving portion 31, and is vertically lifted by the moving portion 31. A nozzle holding portion 34 is disposed in the front end portion of the work arm 33, and a nozzle 41 is held in the lower side of the nozzle holding portion 34. The nozzle 41 is provided with a plurality of nozzles, for example, in the horizontal moving direction of the work arm 33, but only a case where two nozzles are provided is shown in the figure. Figure 1 In order to distinguish the two nozzles 41 from each other, they are sometimes indicated as 41A and 41B, respectively. Each nozzle 41 is capable of movement between a standby portion 14 and a release position for releasing the resist on the central portion of the wafer W, which will be described later, by the action of the moving portion 31.

[0038] ​In addition, an illumination section 35 is provided on the side opposite to the side where the working arm 33 is connected to the nozzle holding section 34, to irradiate light to each nozzle 41. Further, a camera 36 as a photographing section is provided on the lower surface side of the working arm 33, to photograph each liquid surface in the flow path 42 in the nozzle 41 irradiated with light by the illumination section 35. Further, the camera 36 transmits image data obtained by the photographing to the control section 7 described later. The image data is data including brightness information of the photographed area. The optical axis of the camera 36 is directed obliquely downward, and the camera 36 photographs each liquid surface in the flow path 42 in the nozzle 41 described later from a position slightly above.

[0039] Reference is made to FIG. 4 showing the structure of the nozzle 41 and the pipe connected to the nozzle 41. Figure 3 The nozzle 41 is an elongated cylindrical body, and the peripheral surface of the lower side of the nozzle 41 is curved with respect to the peripheral surface of the upper side when viewed from the side, and the lower side of the nozzle 41 is formed in a pointed shape. Further, a flow path 42 for releasing resist downward vertically is provided in the nozzle 41. The nozzle 41 is configured to enable photographing of the liquid surface in the flow path 42 by the camera 36 described above. Specifically, the nozzle 41 is configured to enable transmission of light irradiated from the illumination section 35 with high transmittance, and the transparency of the nozzle 41 can be high or low as long as the light can be transmitted like this. The light irradiated from the illumination section 35 can be, for example, infrared light, or visible light.

[0040] The nozzle holding section 34 is connected to one end of the three-layer pipe 51 provided to each nozzle 41, and each pipe constituting the three-layer pipe 51 is connected from the inside to the outside as an inner pipe 52, a middle pipe 53, and an outer pipe 54, respectively. Further, the illustration of the three-layer pipe 51 is omitted in Figure 1 2 The flow path 55 between the inner pipe 52 and the middle pipe 53 and the flow path 56 between the middle pipe 53 and the outer pipe 54 are connected together via the flow path 37 provided to the nozzle holding section 34. Further, the other end side of the three-layer pipe 51 is provided with a pipe 59 connecting the flow path 55 and the flow path 56 and into which a pump 57 and a temperature adjustment mechanism 58 are inserted.

[0041] ​The flow paths 55, 56, 37 and the flow path in the pipe 59 constitute a circulation passage for circulating a fluid such as water. The pump 57 performs the operation of sucking water from the flow path 56 side and the operation of releasing water to the flow path 55 side. The temperature adjustment mechanism 58 adjusts the temperature of water supplied from the upstream side by the operation of the pump 57 and supplies it to the downstream side. For example, the pump 57, the temperature adjustment mechanism 58 are shared by each of the three-layer pipes 51. Also, during the operation of the resist film forming apparatus 1, the pump 57 periodically performs the above-mentioned sucking and releasing, and water (water after temperature adjustment) is pulsed in the circulation passage. The nozzle 41 supported in the air by the above-mentioned operation arm 33 transmits the vibration caused by the pulsation of the water after temperature adjustment and periodically vibrates in a small amplitude mainly in the up-and-down direction. Therefore, the vibration application part is constituted by the flow paths 55, 56, 37, the flow path in the pipe 59, and the pump 57.

[0042] The flow path 37 of the resist is inside the inner pipe 52, and the resist flowing in this flow path 37 can be temperature-adjusted by the circulation of the water after temperature adjustment described above. The upstream side of the inner pipe 52 is connected to the supply source 45 of the resist via the back suction valve 43 and the pump 44 in this order. The resist stored in the resist supply source 45 is pressurized and delivered to the nozzle 41 by the pump 44 as a processing liquid supply part. Further, by the back suction valve 43 as a sucking part, the part of the inner pipe 52 on the downstream side of the back suction valve 43 is sucked to be under a negative pressure, so as to perform the operation of sucking liquid from the outside of the nozzle 41 to the flow path 42 of the nozzle 41 and the operation of sucking liquid from the flow path 42 side of the nozzle 41 to the inner pipe 52 side.

[0043] The back suction valve 43, the pump 44, and the resist supply source 45 are provided in each nozzle 41, and each nozzle 41 can individually release the resist and form an air layer and a diluent layer in the flow path 42 described later. Further, different kinds of resist are stored in each of the resist supply sources 45. That is, each nozzle 41 is configured to be able to release different resist, and processing is performed using the resist selected according to the lot of the wafer W.

[0044] The standby part 14 is provided on the outside of the cup-shaped body 21. When the wafer W is not processed, each nozzle 41 stands by in a state of entering the recess 15 provided in the standby part 14 from the upper side. Also, the standby part 14 is configured to be able to perform the operation of supplying a diluent (a liquid other than a processing liquid) as an anti-drying liquid to the recess 15 and the operation of discharging the liquid from the recess 15. Therefore, the standby part 14 constitutes an anti-drying liquid supply part.

[0045] Next, the state in which the nozzle 41 is observed along the optical axis of the camera 36 will be described with reference to FIG. 6. The camera 36 is provided on the side of the cup-shaped body 21 opposite to the side on which the nozzles 41 are provided. The camera 36 is configured to be able to take an image of the nozzle 41 from the side of the cup-shaped body 21 opposite to the side on which the nozzles 41 are provided. The camera 36 is provided on the side of the cup-shaped body 21 opposite to the side on which the nozzles 41 are provided. The camera 36 is configured to be able to take an image of the nozzle 41 from the side of the cup-shaped body 21 opposite to the side on which the nozzles 41 are provided. Figure 4, the explanation will be continued. By the cooperation between the above-described operation of supplying the diluent in the standby section 14 and the above-described operation of sucking by the suction valve 43, in the flow path 42 of the nozzle 41, it is possible to become a state (sealed state) in which the air layer 61, the diluent layer 62, the air layer 63, and the resist layer 64 are sequentially formed toward the upstream side. Each nozzle 41 standing by in the standby section 14 is formed in this sealed state, but in Figure 4 In the schematic view of FIG. 10, only the case in which the nozzle 41A is formed in the sealed state is shown. By forming this sealed state, it is possible to suppress the case in which the resist in the flow path 42 is solidified due to drying.

[0046] Due to the formation of the above-described sealed state, a liquid surface 65 is formed between each of the diluent layer 62 and the resist layer 64 and each of the air layers 61 and 63. Further, the air layer 63 is formed for the purpose of preventing the penetration of the diluent from the diluent layer 62 to the resist layer 64. The air layer 61 is formed for the purpose of preventing the diluent from falling from the nozzle 41 during the movement of the nozzle 41.

[0047] Before the nozzle 41 is to be sent out from the standby section 14 to perform processing on the wafer W, the nozzle 41 which is to perform processing only on the wafer W performs an operation of releasing the resist into the recess 15 of the standby section 14 by the operation of the pump 44 (dummy dispense). Due to this, it is possible to remove the air layers 61 and 63, and the diluent layer 62. After the dummy dispense, in order to prevent the resist from dropping as droplets from the flow path 42 of the nozzle 41, the suction valve 43 is operated to suck, and the liquid surface 65 of the resist layer 74 is sucked and rises in the flow path 42, becoming a ready-to-release state. Figure 4 In FIG. 11, the case in which the nozzle 41B becomes the ready-to-release state is shown. After one nozzle 41 becomes the ready-to-release state like this, each nozzle 41 is sent out from the standby section 14.

[0048] Next, the processing of the wafer W in the resist film forming apparatus 1 will be described. In the standby section 14, each nozzle 41 becomes the above-described sealed state and stands by. On the other hand, the wafer W at the front in the batch is placed on the spin chuck 11. The nozzle 41 which is set in advance to perform processing on the wafer W in the batch is caused to perform dummy dispense and become the ready-to-release state. Then, each nozzle 41 is caused to rise from the recess 15 of the standby section 14 to above the wafer W, and the nozzle 41 which has become the ready-to-release state is caused to move to a processing position on the central portion of the wafer W.

[0049] Then, the resist is discharged from the nozzle 41, the wafer W is rotated, and the resist is extended to the peripheral portion of the wafer W, and a resist film is formed. After that, in order to prevent interference with the incoming and outgoing wafer W, the nozzle 41 is temporarily moved away from above the cup-shaped body 21, and the processed wafer W is sent out from the resist film forming apparatus 1. Next, the wafer W of the same lot as the processed wafer W is placed on the rotary chuck 11, and is processed in the same manner as the previously processed wafer W. Then, when the processing of the wafers W belonging to the same lot is completed, the nozzle 41 returns to the standby portion 14, and the used nozzle 41 is brought into the sealed state.

[0050] When a series of processes are performed in this manner, the period during which the nozzle 41 is raised from the recess 15 of the standby portion 14 and positioned above the standby portion 14 is taken as the first abnormality detection period. Also, the period during which the nozzle 41 is moved above the wafer W at the front of the lot, that is, before the resist is discharged to the wafer W, is taken as the second abnormality detection period. In the above-mentioned first abnormality detection period and second abnormality detection period, light is respectively irradiated from the illuminating portion 35, and the nozzle 41 is photographed by the camera 36, so that the liquid surface position and the presence or absence of an abnormality related to the attachment of liquid droplets are determined for each nozzle 41.

[0051] In addition, each abnormality detection period in which photographing is performed in this manner is a period in which the operation of the pump 44 and the back suction valve 43 is not performed as described later, so that the liquid surface position in the nozzle 41 can be detected. That is, it is a continuous period in which the resist is not discharged from the nozzle 41 and the liquid is not sucked into the flow path 42 from the nozzle 41. That is, the abnormality detection period is a period from when the operation of each of the pump 44 and the back suction valve 43 is stopped to when the operation of the above-mentioned either is started next time. In the first abnormality detection period and the second abnormality detection period, photographing is intermittently performed by the camera 36, and a plurality of image data (frames) can be obtained. More specifically, photographing is performed for, for example, 0.05 seconds to 1 second at a frame rate of, for example, 30 fps to 500 fps, further specifically, for example, 30 fps to 120 fps, and further specifically, for example, about 0.66 seconds. Therefore, image data can be obtained at different times from each other. In addition, in order to match the period of liquid surface oscillation, photographing can be performed for, for example, 2 to 3 seconds.

[0052] However, for Figure 4As described above, when the nozzle 41 is in a ready-to-release state, if the level 65 of the resist in the flow path 42 is too low, the resist will drip onto the wafer W. Conversely, if the level 65 of the resist in the flow path 42 is too high, the amount of resist supplied to the wafer W becomes less than the set amount, and the thickness of the resist film will deviate from the set value. On the other hand, for the nozzle 41 in a sealed state, if the level 65 of the resist layer 62 below it is too low, the resist will drip onto the wafer W. Furthermore, if the distance between the upper and lower levels 65 of the resist layer 62 is too small, i.e., if the thickness of the resist layer 62 is too small, the resist layer 64 may dry out. Because the positions of the various levels 65 in the flow path 42 of the nozzle 41 become abnormal as described above, there is a possibility that adverse conditions may occur during the processing of the wafer W. Therefore, a technique for detecting each level 65 based on image data obtained by the camera 36 is desired.

[0053] Figure 5 This is a schematic representation of an ideal image obtained by camera 36 capable of detecting the liquid surface 65, and... Figure 4 Correspondingly, nozzle 41A becomes sealed, and nozzle 41B becomes ready to release. Figure 5 The nozzle 41, which is the subject of the photograph, is not covered with droplets, as described later. Furthermore, in this... Figure 5 and the following Figure 7 In the image, areas with low brightness are blacked out, areas with slightly lower brightness are marked with dots, and areas with high brightness are white. The density of the dots sometimes indicates the degree of brightness. By illuminating the nozzle 41 with light from the illumination unit 35, the outer edge of the nozzle 41 and each liquid surface 65 are photographed in a bright (reflected) state, thus giving the outer edge of the nozzle 41 and each liquid surface 65 a higher brightness than their surroundings in the image. Therefore, the outer edges (edges) of the nozzle 41A in a sealed state and the nozzle 41B in a ready-to-release state can be determined based on the brightness, and the positions of the liquid surfaces 65 in the nozzles 41A and 41B can be detected.

[0054] Consider the situation where detecting the liquid level 65 becomes difficult due to the different states of nozzle 41. (Refer to...) Figure 6 , Figure 7 Let's take a specific example as an example. Figure 6 Nozzle 41, which is the subject of the photograph, Figure 7 From Figure 6 A schematic diagram of the image obtained from nozzle 41. In flow path 42, for example, the resist surface 65 dries and solidifies, such as... Figure 6 As shown, dirt 66, which may be the same size as liquid surface 65, may remain. Therefore, dirt 66, like liquid surface 65, shines during imaging and may appear in the image as an area with the same or approximately the same brightness as liquid surface 65.

[0055] Furthermore, on the outer peripheral surface of the nozzle 41, diluent supplied in the standby section 14 may adhere as droplets 67 and remain there. Since the droplets 67 adhering to the outside of the nozzle 41 overlap with the liquid surface 65, light traveling from the liquid surface 65 to the camera 36 may be blocked, resulting in reduced brightness of the liquid surface 65 in the image. Additionally, in Figure 7 An example is shown where the brightness of the overlapping area is reduced due to the overlap of droplet 67 with a portion of liquid surface 65, indicating that a portion of liquid surface 65 is missing. From this... Figure 7 The image cannot detect the liquid level 65; on the other hand, dirt 66 may be detected as the liquid level 65.

[0056] right Figure 7 Further explanation is provided. When viewed from camera 36, ​​droplet 67 overlaps with the outer edge of nozzle 41. Therefore, similar to light from the liquid surface 65, light from this outer edge is also difficult to incident on camera 36. That is, the portion of the outer edge of nozzle 41 that overlaps with droplet 67, as observed from camera 36, ​​is represented as a low-brightness area in the image. Therefore, in Figure 7 In, with Figure 5 The difference is more obvious in the view that the outer edge of nozzle 41 lacks the area covered by droplets 67.

[0057] Furthermore, as described above, the outer peripheral surface of the nozzle 41 has a curved portion. Due to the position of the liquid surface 65, reflected light from the liquid surface is refracted more significantly at the curved portion of the nozzle 41, thus not sufficiently incident on the camera 36, ​​resulting in lower brightness. Therefore, there is a possibility that the contrast between the liquid surface 65 and its surroundings in the image becomes lower, making the detection of the liquid surface 65 difficult.

[0058] Furthermore, when the aforementioned droplet 67 falls onto the wafer W, processing may encounter adverse conditions. Therefore, it is desirable to detect the droplets 67 adhering to the nozzle 41 in addition to detecting the liquid surface 65 based on the image. When detecting the liquid 67 as described above, the larger the adhering droplet 67, the greater its impact on processing when it falls onto the wafer W. Therefore, it is desirable to infer the size of the droplet 67 and perform processing corresponding to that size.

[0059] The resist film forming apparatus 1 is configured to address the aforementioned problems. The following is a description... Figure 1A computer, i.e., a control section 7, provided in the resist film forming apparatus 1 is shown. The control section 7, which detects the liquid surface 65, has a program storage section, not shown. The program storage section stores therein a program 71 in which commands (step groups) are programmed to cause the resist film forming apparatus 1 to operate as described above to form a resist film on the wafer W. By the program 71, control signals are outputted from the control section 7 to each section of the resist film forming apparatus 1 to form the resist film as described above. Further, by the program 71, detection of the liquid surface 65 of each liquid based on the image data, detection of the droplet 67, estimation of the size of the droplet 67, and abnormality determination based on the results of the detection and the estimation are performed. The program 71 is stored in the program storage section, for example, in a state of being stored in a storage medium such as a hard disk, an optical disk, a magneto-optical disk, a memory card, or a DVD.

[0060] In addition, a reference data 70 for detecting whether or not the droplet 67 is attached to the nozzle 41 is stored in a memory 72 included in the control section 7. The reference data 70, as illustrated, Figure 8 is data of the nozzle 41 in a state where no droplet 67 is attached. More specifically, it is data for determining the position of the outer edge of the nozzle 41 in the image. As the data, for example, it can be non-image data such as coordinate data for determining the position of the outer edge of the nozzle 41, or it can be image data for determining the outer edge of the nozzle 41. In the present embodiment, Figure 8 , for convenience of explanation, the reference data is expressed as an image. The control section 7 also has a warning output section 73 that outputs a warning by sound and picture display, etc. In a case where a positional abnormality of the liquid surface 65 is detected or an abnormality due to attachment of the droplet 67 is detected, the warning is outputted.

[0061] Next, a method of detecting the liquid surface 65 performed by the control section 7 will be described. Figure 9 is a graph in which a plurality of image data 81 obtained during one abnormality detection period are arranged in time series. Further, each nozzle 41 is photographed by the camera 36 in one shot, but for convenience of illustration, only one nozzle 41 is shown as the image data 81.

[0062] The control section 7 superimposes the obtained plurality of image data 81 to produce image data 82. The superimposition processing (frame addition processing) is performed so that the luminance of the pixel at each position of the image data 82 is the maximum value of the luminance of the pixels at the same positions in each of the image data 81. That is, the image data 82 (sometimes referred to as a MAX picture) is produced from the four image data 81 to be described schematically so that the luminance of the pixels at the same positions in the image data 81 is 30, 40, 50, and 60, respectively. In this case, the luminance of the pixel at the position of the image data 82 is made to be the maximum value of 60 among 30, 40, 50, and 60. That is, as a result of comparing the pixels at the same positions in the plurality of image data 81, the pixel having the maximum luminance can be selected as the pixel of the image data 82. The plurality of image data 81 obtained in the same manner are superimposed to produce image data (a MIN picture). The luminance of the pixel at each position of the MIN picture is the minimum value of the luminance of the pixels at the same positions in each of the image data 81.

[0063] Further, for the MAX picture 82 described above, the control section 7 determines the outer edge of the nozzle 41, for example, on the basis of the luminance, and determines the region in which the flow path 42 is present, from the outer edge. Then, as a summary of the detection, it is judged whether or not there is a set of pixels (a feature region) having a luminance value greater than a value set in advance and having a size within a range set in advance in the flow path 42 in each of the MAX picture 82 and the MIN picture. Then, with respect to the feature region, in a portion in which the difference in the number of pixels (area) between the MAX picture and the MIN picture is large, it is likely that the portion in which the luminance greatly changes due to shaking, that is, the liquid surface 65. Therefore, the feature region in which the difference in the number of pixels is greater than a threshold value and, for example, the center of gravity thereof is within a threshold value from the center line in the longitudinal direction of the nozzle 41 is detected as the liquid surface 65. On the other hand, the region in which the difference in the luminance described above is less than a threshold value is detected as the dirt (including a defect) 66.

[0064] More specifically, the detection method of the liquid surface 65 using the MAX picture and the MIN picture will be described. Further, in step S3 of the flow described later, the liquid surface 65 is determined, for example, in the following manner. The MAX picture is binarized, for example, with a threshold value 40 of luminance, and a binarized region (a region that becomes white, which corresponds to the characteristic region described above) that becomes a candidate for the liquid surface 65 is determined from the binarized image. Likewise, the MIN picture is binarized, for example, with the threshold value 40 of luminance, and the above-described binarized region that becomes a candidate for the liquid surface 65 is determined from the binarized image. Then, the binarized region of the MAX picture and the binarized region of the MIN picture are compared in the number of pixels, and the difference in the number of pixels between the above-described binarized regions is calculated. Next, it is determined whether the difference in the number of pixels exceeds a threshold value. When the difference exceeds the threshold value and the positional relationship with the center line of the nozzle 41 satisfies the above-described condition, the determined characteristic region is determined to be the liquid surface 65. In the case where the calculated number of pixels is below the threshold value, the determined characteristic region is regarded as the dirt (including a defect) 66.

[0065] As described above, by binarizing the MAX picture and the MIN picture respectively, it is possible to limit the range in which the characteristic region that is a candidate for the liquid surface 65 exists, and thus the comparison processing (calculation of the difference in the number of pixels) of the MAX picture and the MIN picture becomes easy. Further, in the example described above, the binarization is performed in advance in order to determine the characteristic region, but when the region predicted as the characteristic region in the image is known, the binarization can be performed after the characteristic region is determined, and the above-described comparison processing can be performed.

[0066] Due to the influence of the liquid droplet 67 attached as described above and the influence of the shape of the nozzle 41, sometimes the amount of light incident on the camera 36 from the liquid surface 65 is small. However, the luminance of the pixel of the image data 82 corresponding to the liquid surface 65 becomes equal to or higher than the luminance of the pixel of the image data 81 corresponding to the liquid surface 65. That is, in the image data 82, the contrast of the pixel corresponding to the liquid surface 65 and the pixels around it becomes high. Therefore, by detecting the liquid surface 65 using the image data 82 as described above, compared to the case where the liquid surface 65 is detected using one image data 81, it is possible to improve the detection accuracy.

[0067] Further, as described above, due to the slight vibration of the nozzle 41 caused by the flow of the temperature-adjusted water, the liquid surface 65 shakes. Therefore, the intensity of the light incident on the camera 36 from the liquid surface 65 changes over time, and for example, it is possible to observe that the liquid surface 65 brightens and dims in time series. Thus, sometimes the luminance of the liquid surface 65 is low in one image data 81, and the luminance of the liquid surface 65 is high in the other image data 81. According to the present method, it is possible to prevent the case where the liquid surface 65 cannot be detected by detecting only the image data 81 in which the luminance of the liquid surface 65 is low.

[0068] However, due to the viscosity and color of the liquid, when observing the image in sequence, sometimes the liquid surface 65 can be observed to vibrate periodically instead of brightening and dimming as described above. Because it is a liquid, the vibration of the liquid surface 65 is greater than that of the nozzle 41. The control unit 7 can detect the liquid surface 65 based on its vibration (swaying).

[0069] The detection of the liquid surface 65 based on this vibration will be specifically explained. For multiple image data 81 obtained during an anomaly detection period, the outer edge of the nozzle 41 is determined based on brightness, and then the range of the flow path 42 corresponding to the nozzle 41 is determined. Then, the aforementioned feature region (a set of pixels with a specified size and specified brightness) located within this range is inferred to be the liquid surface 65. From the multiple image data 81, image data 81 containing the feature region inferred to be the liquid surface 65 is selected. Next, for the selected image data 81, the center of gravity of the feature region inferred to be the liquid surface 65 is calculated, for example. Then, in each feature region, the amount of movement of the center of gravity between the image data 81 is detected, and the feature region whose movement exceeds a preset reference value is determined to be the liquid surface 65.

[0070] use Figure 10 To explain in more detail the detection method for the liquid level of 65. Figure 10 Image data 81, selected from feature regions inferred to be the liquid surface 65, are schematically represented side-by-side in chronological order, as indicated by the arrows, showing the sequential evolution of the image states. Furthermore, in Figure 10 In order to prevent the diagram from becoming unclear, the points marked to indicate light and dark and the shaded parts have been omitted in the diagrams representing the images described above.

[0071] exist Figure 10 In the example shown, the feature region corresponding to the liquid surface 65 and the region corresponding to the liquid surface 65 are shown. Figure 6 The feature regions corresponding to the dirt 66 described in the diagram are inferred to be the liquid surface 65, and the centroids of these feature regions are calculated. In the figure, the centroid of the feature region of the actual liquid surface 65 is represented as P1, and the centroid of the feature region of the dirt 69 is represented as P2. The amount of movement of the centroid P1 between the image data 81 is calculated respectively. Figure 10 The movement of the center of gravity P1 is represented as L1, and the movement of the center of gravity P2 is as follows: Here, the movement of the center of gravity P2 is approximately zero, not exceeding the reference value, while the movement of the center of gravity P1 (L1) exceeds the reference value. Therefore, the feature area where the movement of the center of gravity P1 exceeds the reference value can be correctly identified as the liquid surface 65, while the feature area corresponding to the dirt 69 is not identified as the liquid surface 65. That is, the liquid surface 65 is determined based on the positional change of the area with a pre-set brightness between the image data 81.

[0072] Next, the detection method of the liquid droplet 67 by the control section 7 will be described. This detection uses the reference data 70 of the nozzle 41 described in Figure 8 . The control section 7 detects the outer edge of the nozzle 41 in the image based on the brightness of each pixel of the obtained image. Then, the detected outer edge is compared with the outer edge of the nozzle 41 in the reference data 70, and it is detected whether or not the outer edge of the nozzle 41 in the obtained image has a gap. In the case where the reference data 70 is coordinate data, the outer edge of the nozzle 41 is detected in the above-mentioned image, that is, the coordinates of the outer edge are determined, and the determined coordinates are compared with the coordinates of the reference data 70 to detect whether or not there is a gap. As described above, a plurality of image data 81 can be obtained during one abnormality detection period, but for example, any one of the image data 81 is used to detect the gap of the outer edge.

[0073] Then, in the case where the gap of the outer edge is detected, it is considered that the liquid droplet 67 is attached, and the length (the length of the outer edge of the nozzle 41 in the gap portion) L2 of the gap is detected (refer to Figure 7 ). That is, the distance in which the outer edge of the nozzle 41 detected from the image data 81 does not coincide with the outer edge of the nozzle 41 of the data stored in advance is obtained. The length L2 of the gap is considered to correspond to the size of the liquid droplet 67, and abnormality determination is performed as described later.

[0074] Next, one example of the flow of the abnormality determination of the nozzle 41 by the control section 7 during the abnormality detection period, which includes the above-mentioned detection of the liquid surface 65 and the liquid droplet 67, will be described with reference to the flowcharts of Figure 11 , Figure 12 . Here, the steps of the abnormality determination during the first abnormality detection period when the nozzle 41 is transported from the above-mentioned standby section 14 will be described.

[0075] First, after the nozzle 41 is lifted from the standby section 14, light is irradiated to each nozzle 41 with the illumination section 35 and the photographing is performed with the camera 36, and the image data 81 is obtained at the above-mentioned frame rate (step S1 in Figure 11 ). Next, the obtained image data 81 is used to make the overlapped image data (MAX picture) 82 and the MIN picture as described in Figure 9 . Then, the MAX picture 82 and the MIN picture are used to determine whether or not the number and the position of the liquid surface 65 are normal. More specifically, it is determined whether or not the collection of pixels (feature area) having the above-mentioned prescribed brightness and prescribed size is in an appropriate number and position in the range of the flow path 42 in the image (step S3). Further, in the nozzle 41 in the sealed state and the nozzle 41 in the preparation for release state, the appropriate position and number of the liquid surface 65 are different from each other, and therefore, for example, the determination is performed based on the reference set in advance for the nozzle 41 in the release state and the nozzle 41 in the preparation for release state, respectively.

[0076] In step S3, if it is determined that the quantity or position of the liquid surface 65 is abnormal, it is determined whether the number of feature regions in the image data 82 is greater than a predetermined value. That is, it is determined whether the number of feature regions inferred to be the liquid surface 65 in the image is greater than the original number (step S4). If it is determined in step S4 that the number of feature regions is greater than the predetermined value, there is a possibility that dirt 66 is adhering to the nozzle 41. Therefore, as Figure 10 As explained, for each feature region in the image data 81, the centroid of each feature region is calculated, the amount of movement of the centroid between the image data 81 is detected, and the detected movement is compared with the reference value to determine whether each feature region is the liquid surface 65, thus determining the liquid surface 65 (step S5). Then, it is determined whether the position of the determined liquid surface 65 is normal (step S6).

[0077] If, in step S6, the position of the liquid surface 65 is determined to be normal, and in step S2, the quantity and position of the liquid surface 65 are determined to be normal, then the liquid surface 65 is normal, and the processing of the wafer W is not stopped (step S7). On the other hand, if, in step S6, the position of the liquid surface 65 is determined to be abnormal, and in step S4, an abnormality is determined where the number of feature regions is greater than usual, a warning is issued, and the processing of the wafer W is stopped. Therefore, the delivery of nozzle 41 to the wafer W can be stopped (step S8). Furthermore, since the quantity of liquid surfaces was determined to be normal in step S3, the situation in step S4 where an abnormality is determined as described above, where there are no more feature regions, means that the liquid surface 65 to be detected was not detected.

[0078] As described above, anomaly detection is performed for liquid surface 65, and anomaly detection is performed for droplet 67. First, a comparison is made between the baseline data 70 and one of the obtained image data. Figure 12 In step T1), as follows Figure 7 As explained, it is determined whether there is a notch on the outer edge of the nozzle 41 in the obtained image (step T2). In step T2, if a notch is found on the outer edge, it is determined whether the size L2 of the notch exceeds a preset threshold (step T3). If, as described above, the size L2 of the notch corresponds to the size of the droplet 67 and the size L2 of the notch exceeds the threshold, the probability of the droplet 67 dripping from the nozzle 41 is high, therefore a warning is output and the processing of the wafer W is stopped. Thus, it is possible to stop the delivery of the nozzle 41 to the wafer W (step T4).

[0079] In the case where it is determined in step T2 that there is no gap in the outer edge of the nozzle 41 and in the case where it is determined in step T3 that the size of the liquid droplet 67 is below the reference value, the processing of the wafer W is not suspended (step T5). In the case where the processing of the wafer W is not suspended in step S7 of the flow of processing the liquid surface 65 and in this step T5, there is no abnormality due to the liquid surface 65 and the liquid droplet 67, and the nozzle 41 is delivered above the wafer W.

[0080] The flow during the first abnormality detection period immediately after the nozzle 41 is delivered from the standby section 14 is explained, but the same flow is executed during the second abnormality detection period after the nozzle 41 is placed above the wafer W. Further, in the flow during the second abnormality detection period, in the case where it is decided in steps S8, T4 to suspend the processing of the wafer W, the wafer W is not released with the resist from the nozzle 41 delivered above the wafer W. After the time when the resist release is suspended, for example, the processing of the wafer W of the batch to be delivered to the resist film forming apparatus 1 next is suspended, that is, the delivery of the batch to the resist film forming apparatus 1 is suspended, or there is also a case of module block. The module block means that, for each batch to be delivered to the resist film forming apparatus 1, the operation of the delivery mechanism for delivering the wafer W to the resist film forming apparatus 1 is controlled to suspend the delivery of the wafer W.

[0081] For the resist film forming apparatus 1, the detection of the liquid surface 65 in the flow path 42 of the nozzle 41 is performed based on a plurality of image data 81, and therefore, the detection of the liquid surface 65 can be performed with high accuracy. Therefore, it is possible to reliably prevent the occurrence of an abnormality in the liquid processing due to a positional abnormality of the liquid surface 65. Further, for the liquid surface 65, the detection is performed by detecting the change in the position of the feature region of the liquid surface 65 between the image data 81. By detecting the vibration of the liquid surface 65 like this, it is possible to accurately distinguish the liquid surface 65 from the adhering matter of the nozzle 41 other than the liquid surface 65, and as a result, it is possible to more reliably detect the liquid surface 65. In addition, the detection of the liquid surface 65 is performed by the superposition of the image data 81 in addition to the detection based on the vibration of the liquid surface 65 as described above. By performing the detection using different methods like this, it is possible to more reliably detect the liquid surface 65.

[0082] Further, for the resist film forming apparatus 1, it is detected based on the image data 81 whether there is the liquid droplet 67 adhering to the nozzle 41, and it is possible to more reliably prevent the occurrence of an abnormality in the liquid processing. Further, based on the image data 81, the size of the gap in the outer edge of the nozzle 41 corresponding to the size of the liquid droplet 67 adhering to the nozzle 41 is detected, and the abnormality is judged based on the detected size. Therefore, it is possible to sufficiently prevent the suspension of the processing. However, it is also possible to suspend the processing of the wafer W once the liquid droplet 67 is detected regardless of the size thereof.

[0083] In the detection of the presence or absence of the liquid droplet 67, one of the image data 81 is compared with the reference data, but the comparison is not limited to using one of the image data 81 as such. For example, the image data 82 described in the above can be compared with the reference data to detect the presence or absence of the liquid droplet 67. Figure 9

[0084] Further, the detection of the liquid surface 65 based on the vibration is not limited to the above. For example, it can be determined whether the variation of the center of gravity Pl, P2 of the feature region calculated as described above exceeds a reference value, and in addition, whether the moving direction of the center of gravity Pl, P2 is repeated in the up and down direction can also be used as a criterion for determining whether the feature region is the liquid surface 65. Also, since the vibration of the nozzle 41 is periodic, the fluctuation of the liquid surface 65 is also periodic. Therefore, whether the up and down movement of the center of gravity Pl, P2 is periodic can also be used as a criterion for determining whether the feature region is the liquid surface 65. Further, for example, the moving amount of the upper end or the lower end of the feature region can be determined whether it exceeds a reference value to determine whether it is the liquid surface 65. That is, it is not limited to calculating the center of gravity P of the feature region to determine whether it is the liquid surface 65.

[0085] Further, in the creation of the image data 82, all of the image data obtained in the above-described example are overlaid, but for example, only the image data obtained at arbitrary intervals can be overlaid. That is, only a part of the obtained plurality of image data 81 can be used in the detection of the liquid surface 65. Then, in the above-described example, the maximum value of the brightness is obtained by comparing the pixels at the same position of each of the image data 81 with each other, but the pixels at positions slightly deviated from each other can be compared. Specifically, since the nozzle 41 vibrates with a small amplitude as described above, the position thereof is slightly different between the image data 81. The image data 82 is created by overlaying the image data 81 in such a manner that the outer edge of the nozzle 41 coincides, and obtaining the maximum value of the overlaid pixels for each position. By comparing the brightness of the pixels at the positions corresponding to each other (including the same position) between the image data as such, the maximum value can be obtained to determine the position of the liquid surface 65.

[0086] Further, the determination of whether to suspend the processing shown in Figure 11 Figure 12 is one example. For example, in a case where the liquid surface 65 is not detected and the liquid droplet 67 is detected, the processing can be suspended as shown in Figure 7 ​​The liquid surface 65 can be considered normal and processing can continue as usual with the liquid droplet 67 blocking the liquid surface 65 as in the example shown. According to the resist film forming apparatus 1, both the liquid surface 65 and the liquid droplet 67 are detected as described above, and thus the response can be made with high degrees of freedom based on the detection results.

[0087] Further, when the detection of the liquid surface 65 is performed by vibrating the liquid surface 65, a vibrator such as a quartz vibrator can be provided to the working arm 33, and the liquid surface 65 can be vibrated by vibrating the nozzle 41. That is, in the resist film forming apparatus 1, a flow mechanism for the temperature-adjusted water can not be provided. Further, for example, a gas nozzle that releases gas upward can be provided to the resist film forming apparatus 1, and for example, the nozzle 41 can be disposed on the upward side of the gas nozzle when the nozzle 41 is photographed. Then, the liquid surface 65 in the nozzle 41 is shaken by blowing gas from the gas nozzle into the liquid layer in the nozzle 41. That is, the apparatus is not limited to one in which the liquid surface 65 is vibrated by vibrating the nozzle 41. Further, when gas is blown as described above, the liquid droplet 67 attached to the nozzle 41 is blown away or changes position, and thus it can be determined whether the object attached to the nozzle 41 is the liquid droplet 67 or not based on the period during which the gas is blown or the images before and after the gas is blown. Also, in the example described above, the camera 36 and the illumination section 35 are provided to the working arm 33, but for example, the camera 36 and the illumination section 35 can be fixedly provided to the cup-shaped body 21, and abnormality determination can be performed only during the period in which the resist is to be released from the nozzle 41. That is, the positions at which the camera 36 and the illumination section 35 are provided are not limited to the working arm 33.

[0088] In the example described above, the position of the liquid surface 65 and the size of the liquid droplet 67 are different, and as the response, the processing of the wafer W is stopped and a warning is output. The response is not limited to this, and the nozzle 41 can be returned to the standby section 14 and dummy dispensing can be performed, and / or the liquid droplet 67 can be removed by supplying a diluent to the standby section 14. Further, in the example described above, in the case in which the size of the liquid droplet 67 is small, it can be considered that there is no abnormality and no response is performed, and in the case in which the liquid droplet 67 is detected, it can be considered that there is an abnormality regardless of the size, and each of the responses described above can be performed.

[0089] The present technology can be applied to various liquid processing apparatuses other than the resist film forming apparatus 1. For example, the present technology can be applied to an apparatus that supplies a processing liquid, such as a developer for developing an exposed resist film, a liquid for forming an antireflection film, a liquid for forming an insulating film, and the like, from a nozzle to a wafer W. Further, the present technology can be applied to an apparatus that discharges a processing liquid, such as a diluent to be supplied to a wafer W before a pre-wetting process, a liquid for forming a protective film of a resist, an adhesive for bonding a wafer W, and the like, from a nozzle to a wafer W. Further, the resist film forming apparatus 1 described above performs a pre-wetting process before supplying a resist to a wafer W, for example, but the description of the nozzle that performs the pre-wetting process is omitted in order to avoid complication of the description.

[0090] In addition, the camera 36 acquires black-and-white image data, but a camera that acquires color image data can be provided instead of the camera 36. In this case, as a parameter of a pixel, the outer edge of the nozzle 41 and the liquid surface 65 in the image data 81, 82 can be determined based on, for example, RGB values of the image data instead of luminance. That is, detection of the position of the liquid surface 65 and detection of the droplet 67 can be performed based on color in the image. Therefore, as a parameter of a pixel, the use of luminance is not limited.

[0091] Further, the embodiments disclosed in the present application are illustrative in all aspects and should not be considered as limiting. The above-described embodiments can be omitted, replaced, changed in various ways without departing from the scope of the appended claims and the spirit thereof, and can be combined with each other.

Claims

1. A liquid treatment device, characterized in that, include: A mounting section capable of mounting a substrate; A nozzle that supplies processing liquid to the substrate placed on the mounting section for processing by a processing liquid supply section; A nozzle holding part for holding the nozzle; A three-layer tube connected to the nozzle holding part, the three-layer tube including an inner tube, a middle tube and an outer tube from the inside to the outside; A vibration application unit for vibrating a liquid surface, wherein the liquid surface is formed by the treatment liquid in the flow path of the treatment liquid disposed in the nozzle or by a liquid other than the treatment liquid; A camera unit used to capture image data from the nozzle; and The detection unit uses multiple image data points to detect the liquid surface based on the property that the vibration of the liquid surface becomes greater than the vibration of the nozzle generated by the vibration application unit. These multiple image data points are acquired at different times during periods when the processing fluid is not supplied from the nozzle by the processing fluid supply unit. The first flow path between the outer tube and the middle tube of the three-layer tube and the second flow path between the middle tube and the inner tube are connected on one side of the nozzle holding part and on the other side via a third flow path. A pump is provided in the third flow path. The first flow path, the second flow path, and the third flow path constitute a circulation path for fluid circulation. The vibration application unit consists of the first flow path, the second flow path, the third flow path, and the pump. The pump is capable of periodically suctioning and releasing to cause the fluid to pulsate in the circulation path, thereby causing the nozzle to periodically vibrate in the vertical direction.

2. The liquid treatment apparatus as described in claim 1, characterized in that: The detection unit detects the liquid surface by comparing the parameters of pixels at corresponding positions in multiple obtained images.

3. The liquid treatment apparatus as described in claim 2, characterized in that: The parameter of the pixel is brightness. The detection unit calculates the maximum brightness of pixels at corresponding positions in the plurality of images to detect the liquid surface.

4. The liquid treatment apparatus as described in claim 1 or 2, characterized in that: The detection unit detects the liquid surface by measuring the positional changes of pixels within a pre-defined range across multiple images.

5. The liquid treatment apparatus as described in claim 4, characterized in that: The parameter of the pixel is brightness. The detection unit detects the liquid surface based on the positional changes of regions with preset brightness between the plurality of images.

6. The liquid treatment apparatus as described in claim 1, characterized in that: The vibration application part includes: A flow path for the fluid to pass through, used to regulate the temperature of the treatment liquid to be supplied to the nozzle; and A pump used to circulate the fluid in the flow path for the fluid.

7. The liquid treatment apparatus as described in claim 1 or 2, characterized in that: Includes a memory that pre-stores reference data about the nozzle. The detection unit determines whether droplets are attached to the outside of the nozzle based on at least one of the multiple image data and the reference data.

8. The liquid treatment apparatus as described in claim 7, characterized in that: The detection unit is a control unit that infers the size of the droplet and outputs a control signal based on the inferred size for appropriate processing.

9. The liquid treatment apparatus as described in claim 1 or 2, characterized in that: The detection unit is a control unit, which outputs a control signal to respond when the detected abnormal liquid level position is detected.

10. The liquid treatment apparatus as described in claim 1 or 2, characterized in that, include: An anti-drying fluid is supplied to an anti-drying fluid supply section on the outside of the nozzle, the anti-drying fluid being used to prevent the processing fluid inside the nozzle from drying out; and A suction section for drawing the anti-drying liquid from the nozzle. The liquid other than the treatment liquid is this anti-drying liquid. The distinct moments are those during periods when the attraction is not performed by the attraction unit.

11. A liquid detection method for a liquid treatment device, characterized in that: The liquid treatment device includes: A mounting section capable of mounting a substrate; A nozzle that supplies processing liquid to the substrate placed on the mounting section for processing using a processing liquid supply section; and a nozzle holding section for holding the nozzle. A three-layer tube connected to the nozzle holding part, the three-layer tube comprising an inner tube, a middle tube, and an outer tube from the inside to the outside; and A vibration application unit for vibrating a liquid surface, wherein the liquid surface is formed by the treatment liquid in the flow path of the treatment liquid disposed within the nozzle, or by a liquid other than the treatment liquid. The first flow path between the outer tube and the middle tube of the three-layer tube and the second flow path between the middle tube and the inner tube are connected on one side of the nozzle holding part and on the other side via a third flow path. A pump is provided in the third flow path. The first flow path, the second flow path, and the third flow path constitute a circulation path for fluid circulation. The vibration application unit comprises a first flow path, a second flow path, a third flow path, and a pump. The pump is capable of periodically suctioning and releasing to cause the fluid to pulsate in the circulation path, thereby causing the nozzle to periodically vibrate in the vertical direction. The liquid detection method includes: The step of obtaining image data by photographing the nozzle with the imaging unit; and The step of detecting the liquid surface using a detection unit, using multiple image data, and taking advantage of the property that the vibration of the liquid surface becomes greater than the vibration of the nozzle generated by the vibration application unit, is based on the vibration of the liquid surface. These multiple image data are obtained at different times during a period when the processing liquid is not supplied from the nozzle by the processing liquid supply unit.

Images