JP6161489B2 - Discharge inspection apparatus and substrate processing apparatus - Google Patents

Description

  The present invention relates to a discharge inspection apparatus for inspecting a liquid discharge operation from a plurality of discharge ports, and a substrate processing apparatus including the discharge inspection apparatus.

  Conventionally, in a manufacturing process of a semiconductor substrate (hereinafter simply referred to as “substrate”), various processes are performed on a substrate having an insulating film such as an oxide film using a substrate processing apparatus. For example, a cleaning process is performed to remove particles and the like attached on the surface of the substrate by supplying a cleaning liquid to the surface of the substrate.

  Patent Document 1 discloses a substrate processing apparatus that discharges a photoresist liquid onto a substrate from one processing liquid supply nozzle disposed above the substrate. In this apparatus, the CCD camera is directed between the processing liquid supply nozzle and the substrate, and the liquid column of the processing liquid discharged from the processing liquid supply nozzle is imaged. Then, the liquid column width of the imaged processing liquid (that is, the discharge width from the processing liquid supply nozzle) is compared with a predetermined reference width, and when it is smaller than the reference width, it is detected as an abnormal discharge.

  Patent Document 2 discloses a liquid processing apparatus that supplies a processing liquid onto a substrate from a processing liquid nozzle. In this apparatus, 11 nozzles arranged in a line in a straight line are held by the nozzle head portion. In addition, a line-shaped laser beam is irradiated to a region from the tip portion of these nozzles to the substrate surface, and a liquid column of the resist solution discharged from each nozzle is imaged by a camera directed to the region. Then, by comparing the imaging result with the reference information obtained by imaging the state in which the resist solution is normally ejected from the nozzle, it is determined whether the resist solution is ejected from the nozzle and whether the ejection state has changed. Is done.

  On the other hand, Patent Document 3 discloses a substrate processing apparatus that discharges fine droplets of a processing liquid toward a substrate from a plurality of discharge ports. In the apparatus, a plurality of discharge port arrays in which a plurality of discharge ports are arranged in one row are provided.

JP 11-329936 A JP 2012-98812 A JP 2012-209513 A

  By the way, in an apparatus such as Patent Document 3, even if it is determined whether or not processing liquid is being discharged from a plurality of discharge ports, a plurality of discharge port arrays each having a large number of discharge ports are arranged in an array of discharge ports. Since the liquid droplets are arranged in a direction crossing the direction, the fine liquid droplets from the respective discharge ports overlap with each other, and it is not easy to determine which fine liquid droplet corresponds to which discharge port.

  Further, as one of abnormal discharges of micro droplets, there is an oblique discharge that is discharged out of a predetermined discharge direction. As a method for detecting such oblique ejection, it is conceivable to compare the interval between the minute droplets with a normal value. However, since the interval between the minute droplets appears large at the discharge port close to the observation viewpoint and appears small at the discharge port far from the observation viewpoint, it is not easy to determine whether the discharge is normal discharge or oblique discharge. In addition, the size of each minute droplet also changes depending on the distance from the observation viewpoint.

  The present invention has been made in view of the above problems, and an object of the present invention is to accurately determine the quality of a discharge operation at a plurality of discharge ports.

The invention according to claim 1 is a discharge inspection device that inspects the discharge operation of liquid from a plurality of discharge ports, and emits a plurality of planar lights along a predetermined light existence surface. A light emitting unit that irradiates light to the plurality of flying bodies when the plurality of flying bodies that are liquid ejected from the discharge ports pass through the light existence plane, and the plurality of flying bodies that pass through the light existence plane. The imaging unit that obtains an inspection image including a plurality of bright spots appearing on the plurality of flying objects, and the light emitting unit emits light in a state where liquid is normally ejected from the plurality of ejection ports. A reference image storage unit that stores a reference image, which is an image acquired by the imaging unit while being emitted, and the quality of the discharge operation at the plurality of discharge ports is determined based on a difference between the reference image and the inspection image. and a determination unit, in the image pickup unit Image direction is inclined with respect to a plane perpendicular to the predetermined ejection direction of the plurality of projectile.
The invention according to claim 2 is an ejection inspection apparatus that inspects the ejection operation of liquid from a plurality of ejection ports, and emits a plurality of planar lights along a predetermined light existence surface. A light emitting unit that irradiates light to the plurality of flying bodies when the plurality of flying bodies that are liquid ejected from the discharge ports pass through the light existence plane, and the plurality of flying bodies that pass through the light existence plane. The imaging unit that obtains an inspection image including a plurality of bright spots appearing on the plurality of flying objects, and the light emitting unit emits light in a state where liquid is normally ejected from the plurality of ejection ports. A reference image storage unit that stores a reference image, which is an image acquired by the imaging unit while being emitted, and the quality of the discharge operation at the plurality of discharge ports is determined based on a difference between the reference image and the inspection image. And a light-existing surface is provided in front of It is inclined with respect to a plane perpendicular to the predetermined ejection direction of a plurality of projectile.
The invention described in claim 3 is the ejection inspection apparatus according to claim 1 or 2, wherein the inspection image is a still image of one frame.
The invention according to claim 4 is an ejection inspection device that inspects the liquid ejection operation from the plurality of ejection ports, and emits a plurality of planar light beams along a predetermined light existence surface. A light emitting unit that irradiates light to the plurality of flying bodies when the plurality of flying bodies that are liquid ejected from the discharge ports pass through the light existence plane, and the plurality of flying bodies that pass through the light existence plane. In the state where the liquid is normally ejected from the plurality of ejection ports, and an imaging unit that acquires an inspection image that is a still image of one frame including a plurality of bright spots that appear on the plurality of flying objects. A reference image storage unit that stores a reference image that is an image acquired by the imaging unit while emitting light from the light emitting unit, and a plurality of outlets based on a difference between the reference image and the inspection image A determination unit for determining the quality of the discharge operation Obtain.
A fifth aspect of the present invention is the ejection inspection apparatus according to any one of the first to fourth aspects, wherein the plurality of bright spots are extracted by performing binarization processing on the inspection image. .

A sixth aspect of the present invention is the discharge inspection apparatus according to any one of the first to fifth aspects , wherein the plurality of discharge ports are discharge ports each arranged linearly in the discharge port array direction. It includes a plurality of discharge port arrays as a set, and the plurality of discharge port arrays are arranged in a direction inclined with respect to the discharge port arrangement direction.

A seventh aspect of the present invention is the ejection inspection apparatus according to any one of the first to sixth aspects , wherein the determination unit includes the one bright spot in the inspection image and the one bright spot in the reference image. When the distance between the bright spot corresponding to the point is larger than a predetermined distance, it is determined that oblique discharge has occurred at the discharge port corresponding to the one bright spot.

The invention according to claim 8 is a substrate processing apparatus, comprising: a substrate holding unit that holds a substrate; and a discharge head that discharges liquid from a plurality of discharge ports toward the substrate to perform a predetermined process on the substrate. When, and a discharge inspection device according to any one ejection operation of claims 1 to 7 for inspecting the liquid from the plurality of ejection ports of the ejection head.

  In the present invention, it is possible to accurately determine the quality of the discharge operation at the plurality of discharge ports.

It is a front view of the substrate processing apparatus concerning one embodiment. It is a top view of a substrate processing apparatus. It is a bottom view which shows the lower surface of a discharge head. It is a block diagram which shows the function of a control unit. It is a side view of a discharge head and a standby pod. It is a perspective view which shows an ejection head, a light emission part, and an imaging part. It is a figure which shows a test | inspection image. It is a figure which shows a difference image.

  FIG. 1 is a front view of a substrate processing apparatus 1 according to an embodiment of the present invention. FIG. 2 is a plan view of the substrate processing apparatus 1. In FIG. 2, the orientation of the substrate processing apparatus 1 is changed from FIG. The substrate processing apparatus 1 is a single-wafer type apparatus that processes semiconductor substrates 9 (hereinafter simply referred to as “substrates 9”) one by one. In the substrate processing apparatus 1, a liquid is discharged to the substrate 9 to perform a predetermined process. In the present embodiment, a cleaning process for removing particles and the like from the substrate 9 is performed by discharging droplets of the cleaning liquid onto the substrate 9. In the substrate processing apparatus 1, for example, droplets having a diameter of about 20 μm are ejected toward the substrate 9 in a spray form.

  As shown in FIGS. 1 and 2, the substrate processing apparatus 1 includes a substrate holding unit 21, a cup unit 22, a substrate rotating mechanism 23, a processing liquid supply unit 3, a head moving mechanism 35, and a protective liquid supply unit. 36, a standby pod 4, a discharge inspection unit 5, a chamber 6, and a control unit. The chamber 6 includes a substrate holding unit 21, a cup unit 22, a substrate rotating mechanism 23, a processing liquid supply unit 3, a head moving mechanism 35, a protective liquid supply unit 36, a standby pod 4, and a discharge inspection unit 5. To house. The chamber 6 is a light shielding chamber that blocks light from entering the internal space 60 from the outside. 1 and 2, the chamber 6 is indicated by a broken line, and the inside of the chamber 6 is illustrated.

  The substrate holding unit 21 holds the substrate 9 in a state where one main surface 91 (hereinafter referred to as “upper surface 91”) of the substrate 9 is directed upward in the chamber 6. A fine pattern such as a circuit pattern is formed on the upper surface 91 of the substrate 9. The cup portion 22 is a substantially cylindrical member surrounding the substrate 9 and the substrate holding portion 21. The substrate rotation mechanism 23 is disposed below the substrate holding unit 21. The substrate rotation mechanism 23 rotates the substrate 9 together with the substrate holder 21 in a horizontal plane around a rotation axis that passes through the center of the substrate 9 and is perpendicular to the upper surface 91 of the substrate 9.

  The processing liquid supply unit 3 includes a discharge head 31 that discharges the processing liquid downward, and a processing liquid pipe 32 that supplies the processing liquid to the discharge head 31. In FIG. 2, illustration of the processing liquid piping 32 is omitted. The discharge head 31 is disposed above the substrate holding part 21 inside the cup part 22. In other words, the lower surface of the ejection head 31 is located between the upper opening 220 of the cup portion 22 and the upper surface 91 of the substrate 9. The discharge head 31 is a device that continuously discharges minute droplets separated from each other from a plurality of discharge ports described later. The processing liquid is discharged toward the upper surface 91 of the substrate 9 by the discharge head 31. As the treatment liquid, a liquid such as pure water (preferably deionized water (DIW)), carbonated water, a mixed solution of ammonia water and hydrogen peroxide water is used. The design discharge direction of the processing liquid from the discharge head 31 is approximately parallel to the vertical direction (that is, the direction of gravity).

  FIG. 3 is a bottom view showing the lower surface 311 of the ejection head 31. A plurality of discharge ports including four discharge port arrays 313 a to 313 d are provided on the lower surface 311 of the discharge head 31. Each of the discharge port arrays 313a to 313d is a set of a plurality of discharge ports 314a to 314d arranged substantially linearly in the left-right direction in FIG. 3 at a predetermined arrangement pitch. The diameter of each discharge port 314a-314d is about 5 micrometers-10 micrometers. In FIG. 3, each of the discharge ports 314a to 314d is drawn larger than the actual size, and the number of the discharge ports 314a to 314d is drawn smaller than the actual size. In FIG. 3, a discharge port arrangement region 316 where a plurality of discharge ports 314 a to 314 d are provided on the lower surface 311 of the discharge head 31 is surrounded by a two-dot chain line. The discharge port arrangement region 316 is substantially rectangular. In the ejection head 31, minute droplets of the processing liquid are ejected from each of the plurality of ejection ports 314a to 314d.

  In the following description, the left-right direction in FIG. 3 which is the discharge port arrangement direction of each of the discharge port arrays 313a to 313d is referred to as “array direction”. Each of the discharge port arrays 313a to 313d has a linear shape extending in the arrangement direction. The ejection port arrays 313a to 313d are arranged in parallel to each other in a direction perpendicular to the arrangement direction (that is, the vertical direction in FIG. 3). Note that the ejection port arrays 313a to 313d do not necessarily need to be arranged perpendicular to the arrangement direction, but may be arranged in a direction inclined with respect to the arrangement direction.

  In the following description, the discharge port arrays 313a to 313d arranged from the upper side to the lower side in FIG. 3 are respectively referred to as “first discharge port array 313a”, “second discharge port array 313b”, and “third discharge port”. They are referred to as “outlet row 313c” and “fourth discharge port row 313d”. Furthermore, the plurality of discharge ports 314a of the first discharge port row 313a are referred to as “first discharge ports 314a”, and the plurality of discharge ports 314b of the second discharge port row 313b are referred to as “second discharge ports 314b”. The plurality of discharge ports 314c of the third discharge port row 313c are referred to as “third discharge ports 314c”, and the plurality of discharge ports 314d of the fourth discharge port row 313d are referred to as “fourth discharge ports 314d”.

  In the direction perpendicular to the arrangement direction, the distance between the first outlet row 313a and the second outlet row 313b is equal to the distance between the third outlet row 313c and the fourth outlet row 313d. The distance is smaller than the distance between the second discharge port array 313b and the third discharge port array 313c. The second discharge port array 313b is arranged so as to be shifted from the first discharge port array 313a by a predetermined shift distance on the right side in FIG. 3, which is one side in the arrangement direction. The fourth discharge port array 313d is arranged to be shifted from the third discharge port array 313c by the shift distance on the right side in FIG. The shift distance is a distance smaller than the above-described arrangement pitch, for example, a distance that is half of the arrangement pitch.

  In the ejection head 31, when viewed from a direction perpendicular to the arrangement direction and parallel to the lower surface 311 of the ejection head 31, the plurality of first ejection ports 314a and the plurality of second ejection ports 314b are alternately arranged in the arrangement direction. The plurality of third discharge ports 314c and the plurality of fourth discharge ports 314d are alternately arranged in the arrangement direction. In addition, the plurality of first discharge ports 314a and the plurality of third discharge ports 314c overlap each other, and the plurality of second discharge ports 314b and the plurality of fourth discharge ports 314d overlap each other.

  As shown in FIGS. 1 and 2, the head moving mechanism 35 includes an arm 351, a rotating shaft 352, a head rotating mechanism 353, and a head lifting mechanism 354. The arm 351 extends in the horizontal direction from the rotation shaft 352. A discharge head 31 is attached to the tip of the arm 351. The head rotating mechanism 353 rotates and moves the ejection head 31 in the horizontal direction around the rotation shaft 352 together with the arm 351. The head lifting mechanism 354 moves the ejection head 31 in the vertical direction together with the arm 351. The head rotation mechanism 353 includes, for example, an electric motor. The head lifting mechanism 354 includes a ball screw mechanism and an electric motor, and can accurately position the ejection head 31. The head lifting mechanism 354 may include an air cylinder.

  The protective liquid supply unit 36 is directly or indirectly fixed to the discharge head 31 and discharges the protective liquid obliquely downward. As the protective liquid, liquids such as pure water (preferably deionized water), carbonated water, a mixed solution of ammonia water and hydrogen peroxide water are used as in the case of the above-described treatment liquid. The protective liquid may be the same type of liquid as the treatment liquid or may be a different type of liquid. In the substrate processing apparatus 1, the protective liquid discharged in the form of a liquid column from the protective liquid supply unit 36 toward the upper surface 91 of the substrate 9 spreads on the substrate 9 below the discharge head 31, thereby directly below the discharge head 31. A protective liquid film (hereinafter referred to as “protective liquid film”) having a predetermined thickness is formed. The protective liquid supply unit 36 moves together with the ejection head 31 by the head rotation mechanism 353 and the head lifting mechanism 354.

  FIG. 4 is a block diagram showing functions of the control unit 7. In FIG. 4, the configuration other than the control unit 7 is also drawn. The control unit 7 includes a process control unit 71, an inspection control unit 72, and an inspection calculation unit 73. The substrate 9 is processed by controlling the substrate rotation mechanism 23, the processing liquid supply unit 3, the head moving mechanism 35, the protective liquid supply unit 36, and the like by the processing control unit 71. By controlling the processing liquid supply unit 3, the head moving mechanism 35, the discharge inspection unit 5, and the like by the inspection control unit 72, the processing liquid from the plurality of discharge ports 314 a to 314 d (see FIG. 3) of the discharge head 31. The ejection operation is inspected.

  The inspection calculation unit 73 is a part of the discharge inspection unit 5 and includes a reference image storage unit 731 and a determination unit 75. The reference image storage unit 731 stores a reference image 732 described later in advance. The determination unit 75 includes a misalignment correction unit 751 and a pass / fail determination unit 752. The reference image storage unit 731 and the determination unit 75 are used for the above-described ejection operation inspection.

  When processing the substrate 9 in the substrate processing apparatus 1 shown in FIGS. 1 and 2, first, the substrate 9 is carried into the chamber 6 and is held by the substrate holding unit 21. When the substrate 9 is carried in, the ejection head 31 stands by at a standby position on the standby pod 4 provided outside the cup portion 22 as indicated by a two-dot chain line in FIG. FIG. 5 is an enlarged side view showing the ejection head 31 located at the standby position together with the standby pod 4. The standby pod 4 is a substantially rectangular parallelepiped container, and has an opening at the top. At the standby position, a part of the ejection head 31 is inserted into the standby pod 4 through the opening. In FIG. 5, the protective liquid supply unit 36 is not shown. In addition, an ejection head 31 located in an inspection area to be described later is indicated by a two-dot chain line. As shown in FIGS. 1 and 2, when the substrate 9 is held by the substrate holding unit 21, the substrate rotation mechanism 23 is driven by the processing control unit 71 (see FIG. 4), and the rotation of the substrate 9 is started.

  Subsequently, the head rotation mechanism 353 and the head lifting mechanism 354 are driven by the processing control unit 71, and the ejection head 31 and the protective liquid supply unit 36 are lifted from the standby position and moved downward above the cup unit 22. To do. Accordingly, the ejection head 31 and the protective liquid supply unit 36 move to the inside of the cup unit 22 and above the substrate holding unit 21 through the upper opening 220 of the cup unit 22. Next, supply of the protective liquid from the protective liquid supply unit 36 onto the substrate 9 is started, and a protective liquid film covering a part of the upper surface 91 of the substrate 9 is formed. In addition, the discharge of the processing liquid from the plurality of discharge ports 314a to 314d (see FIG. 3) of the discharge head 31 toward the upper surface 91 of the substrate 9 on which the protective liquid film is formed (that is, the injection of microdroplets) is started. Is done. The protective liquid film covers a plurality of design landing points (that is, landing points of the micro droplets) on the substrate 9 of the processing liquid from the plurality of discharge ports 314a to 314d.

  A number of micro droplets ejected from the ejection head 31 toward the protective liquid film collide with the protective liquid film on the upper surface 91 of the substrate 9 and indirectly collide with the upper surface 91 of the substrate 9 through the protective liquid film. To do. Then, foreign matters such as particles adhering to the upper surface 91 of the substrate 9 are removed from the substrate 9 by the impact caused by the collision of the minute droplets of the processing liquid. In other words, the cleaning process of the upper surface 91 of the substrate 9 is performed by the kinetic energy indirectly applied to the substrate 9 through the protective liquid film by the fine droplets of the processing liquid.

  In this way, the microdroplets of the processing liquid collide with the substrate 9 through the protective liquid film, so that the microdroplets are formed on the upper surface 91 of the substrate 9 as compared with the case where the microdroplets directly collide with the substrate. The substrate 9 can be cleaned while preventing or suppressing damage to the pattern or the like. In addition, since the portion of the substrate 9 on which the cleaning process is performed is covered with the protective liquid, it is possible to prevent or suppress particles and the like removed from the substrate 9 from reattaching to the upper surface 91 of the substrate 9. it can.

  In the substrate processing apparatus 1, the ejection head 31 and the protective liquid supply unit 36 are rotated by the head rotation mechanism 353 in parallel with the discharge of the protective liquid and the processing liquid. The ejection head 31 and the protective liquid supply unit 36 repeat horizontal reciprocation between the upper part of the rotating substrate 9 and the upper part of the outer edge of the substrate 9. Thereby, the cleaning process is performed on the entire upper surface 91 of the substrate 9. The protective liquid and the processing liquid supplied to the upper surface 91 of the substrate 9 are moved to the edge of the substrate 9 together with the removed foreign matter by the rotation of the substrate 9 and scattered from the edge of the substrate 9 to the outside. The protective liquid and the processing liquid splashed from the substrate 9 are received by the cup portion 22 and discarded or collected.

  When the predetermined process (that is, the cleaning process of the substrate 9) with the processing liquid from the discharge head 31 is completed, the discharge of the protective liquid and the processing liquid is stopped. The ejection head 31 and the protective liquid supply unit 36 are raised above the upper opening 220 of the cup unit 22 by the head lifting mechanism 354, and are moved from above the substrate 9 to the inspection region above the standby pod 4 by the head rotation mechanism 353. And rotate.

  The inspection area is an area above the standby position described above. The inspection area is a small area having a predetermined design inspection position (hereinafter referred to as “design inspection position”) as a substantial center. In other words, the inspection area includes a design inspection position and a position in the vicinity of the design inspection position. When the discharge head 31 rotates from above the substrate 9 to above the standby pod 4, the discharge head 31 stops at any position in the inspection region. In the inspection area, the discharge inspection unit 5 periodically or as necessary inspects the discharge operation of the processing liquid from the plurality of discharge ports 314a to 314d of the discharge head 31.

  FIG. 6 is a perspective view showing the ejection head 31 in the inspection region and the ejection inspection unit 5 disposed around the ejection head 31. The discharge inspection unit 5 includes a light emitting unit 51 and an imaging unit 52. The light emitting unit 51 and the imaging unit 52 are disposed obliquely below the ejection head 31, avoiding directly below the ejection head 31. The light emission part 51 and the imaging part 52 are controlled by the inspection control part 72 of the control unit 7, as shown in FIG.

  The light emitting unit 51 illustrated in FIG. 6 includes a light source and an optical system that converts light from the light source into linear light extending in a substantially horizontal direction. As the light source, for example, a laser diode or an LED (light emitting diode) element is used. The light emitting unit 51 emits light toward the lower side of the ejection head 31 along a light existence surface that is a predetermined virtual surface. In FIG. 6, the optical axis J <b> 1 of the light emitting portion 51 is drawn with a one-dot chain line, and the outline of the planar light emitted from the light emitting portion 51 is indicated with a two-dot chain line denoted by reference numeral 510.

  The planar light 510 from the light emitting portion 51 passes directly under the ejection head 31 in the vicinity of the lower surface 311 of the ejection head 31. In the substrate processing apparatus 1, a predetermined drive signal is sent from the inspection control unit 72 to the processing liquid supply unit 3 and is directed from the plurality of discharge ports 314 a to 314 d (see FIG. 3) of the discharge head 31 toward the inside of the standby pod 4. The processing liquid is discharged. Then, a plurality of flying bodies that are processing liquids discharged from the plurality of discharge ports 314 a to 314 d of the discharge head 31 located in the inspection region pass through the above-described light existence surface (that is, pass through the planar light 510). ), The light emitting unit 51 emits light to the plurality of flying objects. The planar light 510 is approximately perpendicular to the designed ejection direction of the processing liquid from the ejection head 31 (that is, a predetermined ejection direction determined in advance for a plurality of flying objects). Strictly speaking, the planar light 510 (that is, the light existing surface) is inclined by a slight angle (for example, 5 ° to 10 °) with respect to a plane perpendicular to the predetermined ejection direction of the plurality of flying objects. Preferably it is.

  The imaging unit 52 is disposed below the light existence surface with the imaging axis J2 facing the planar light 510 positioned below the ejection head 31. The imaging direction (that is, the direction in which the imaging axis J2 faces) in the imaging unit 52 is inclined with respect to a plane perpendicular to the predetermined ejection direction of the plurality of flying objects. As the imaging unit 52, for example, a charge-coupled device (CCD) camera is used. The imaging unit 52 acquires an inspection image including a plurality of bright spots appearing on the plurality of flying bodies by imaging the processing liquid (that is, a plurality of flying bodies) that passes through the planar light 510. The imaging unit 52 is arranged at a position where the first discharge port array 313a is visible on the front side among the four discharge port arrays 313a to 313d in FIG.

  In the ejection inspection unit 5, one frame of a still image is extracted as an inspection image from the imaging result obtained by the imaging unit 52. The inspection image is sent to the inspection calculation unit 73 (see FIG. 4) of the control unit 7. In the inspection calculation unit 73, binarization processing is performed on the inspection image to extract a plurality of bright spots and remove background noise and the like.

  FIG. 7 is a diagram showing the inspection image 8. In the inspection image 8, a plurality of bright spots 81 respectively corresponding to the plurality of ejection ports 314a to 314d of the ejection head 31 are arranged in a direction corresponding to the arrangement direction of the ejection ports 314a to 314d. In the ejection inspection unit 5, since the planar light 510 has a slight thickness, each bright spot 81 has a substantially elliptical shape that is long in the direction corresponding to the vertical direction in the inspection image 8.

  Subsequently, the inspection image 8 and the reference image 732 stored in advance in the reference image storage unit 731 are compared by the positional deviation correction unit 751 of the determination unit 75. In the substrate processing apparatus 1, the reference image 732 is generated when the ejection head 31 is positioned at the design inspection position in the inspection area and the processing liquid is normally ejected from the plurality of ejection ports 314 a to 314 d. It is an image acquired by the imaging unit 52 while emitting the planar light 510 from the emission unit 51. The reference image 732 is acquired before the substrate 9 is processed in the substrate processing apparatus 1 (for example, before the substrate processing apparatus 1 is shipped at the manufacturing site of the substrate processing apparatus 1), and is similar to the inspection image 8. After the binarization process is performed, it is stored in advance in the reference image storage unit 731.

  Based on the inspection image 8 and the reference image 732, the positional deviation correction unit 751 obtains a relative deviation (hereinafter referred to as “image deviation”) of the inspection image 8 with respect to the reference image 732. The image shift is caused by a difference between the position of the ejection head 31 when the inspection image 8 is acquired and the design inspection position. The amount of image shift is calculated, for example, until the difference between the inspection image 8 and the reference image 732 is minimized (that is, the overlap between the plurality of bright spots 81 of the inspection image 8 and the plurality of bright spots of the reference image 732). The inspection image 8 is moved in the vertical and horizontal directions in FIG. 7, rotated around a rotation axis perpendicular to the inspection image 8, and the inspection image 8 is enlarged or reduced. Is done. The amount of movement, rotation, and magnification of the inspection image 8 when the difference between the inspection image 8 and the reference image 732 is minimized is the image shift amount of the inspection image 8. The image shift amount may be obtained by applying a general image processing function for pattern matching to the inspection image 8 and the reference image 732.

  The position deviation correction unit 751 corrects the image deviation of the inspection image 8 based on the obtained image deviation amount. Specifically, the position of the plurality of bright spots 81 on the inspection image 8 is corrected to a position when it is assumed that the inspection image 8 is acquired in a state where the ejection head 31 is positioned at the design inspection position in the inspection region. Is done.

  Next, the quality determination unit 752 of the determination unit 75 generates a difference image 82 between the reference image 732 and the inspection image 8 as shown in FIG. Specifically, first, the pixel value of the corresponding pixel in the inspection image 8 is subtracted from the pixel value of each pixel of the reference image 732. In the reference image 732 and the inspection image 8, the pixel value of the pixel included in each bright spot is positive, and the pixel value of the pixel included in the background is zero. Therefore, at the position where the bright spot of the reference image 732 and the bright spot 81 of the inspection image 8 overlap, the difference value that is a value obtained by subtracting the pixel value of the inspection image 8 from the pixel value of the reference image 732 is zero. Also, the difference value is zero at the position where the background of the reference image 732 and the background of the inspection image 8 overlap. On the other hand, the difference value is positive at a position where the bright spot of the reference image 732 exists but the bright spot 81 of the inspection image 8 does not exist. At the position where the bright spot 81 of the inspection image 8 exists but the bright spot of the reference image 732 does not exist, the difference value is negative.

  In the pass / fail judgment unit 752, the gradation value of a pixel having a negative difference value is set to the darkest zero, the gradation value of a pixel having a zero difference value is set to 127 of intermediate brightness, and the gradation value of a pixel having a positive difference value is set. The difference image 82 is generated with the value 255 being the brightest. In FIG. 8, only the outline of the first region 821 that is a set of pixels having a gradation value of 255 is shown. The second region 822, which is a set of pixels having a gradation value of 127, is indicated by parallel diagonal lines. A third region 823, which is a set of pixels having a gradation value of zero, is shown in a solid color.

  Next, the quality determination unit 752 extracts the first region 821 and the third region 823 from the difference image 82. In FIG. 8, one first area 821 and one third area 823 adjacent to the first area 821 exist in the left area of the difference image 82. In addition, one first area 821 exists in the right area of the difference image 82.

  One first region 821 on the left side corresponds to one bright spot on the reference image 732 and indicates that the bright spot 81 does not exist on the inspection image 8 at a position corresponding to the bright spot. Further, one third region 823 adjacent to the first region 821 corresponds to one bright spot 81 on the inspection image 8, and a bright spot at a position corresponding to the bright spot 81 on the reference image 732. Indicates that does not exist. Therefore, in the pass / fail judgment unit 752, the processing liquid is not discharged in the designed discharge direction at the discharge port corresponding to the first region 821, and the processing liquid is discharged obliquely in the direction toward the third region 823. It is determined.

  In the pass / fail determination unit 752, a distance between the first region 821 and the third region 823 (for example, a distance between the centers of gravity) is obtained. The distance is a distance between one bright spot 81 corresponding to the third region 823 on the inspection image 8 and a bright spot corresponding to the one bright spot 81 on the reference image 732. When the distance is larger than the predetermined distance, it is determined that a discharge failure of oblique discharge has occurred at the discharge port corresponding to the one bright spot 81. The occurrence of the ejection failure is notified to an operator or the like through the notification unit 79 (see FIG. 4). On the other hand, when the distance is equal to or less than the predetermined distance, the processing liquid from the discharge port corresponding to the one bright spot 81 is discharged in a direction slightly shifted from the designed discharge direction by a shift amount within an allowable range. It is determined that At this time, notification to the worker or the like through the notification unit 79 is not performed.

  On the inspection image 8, the distance between the bright points 81 adjacent in the arrangement direction decreases as the distance from the imaging unit 52, which is the observation viewpoint (that is, from the near side to the far side). For this reason, the predetermined distance is similarly reduced as the bright spot 81 is separated from the imaging unit 52.

  One first area 821 on the right side of the difference image 82 also corresponds to one bright spot on the reference image 732, and that the bright spot 81 does not exist on the inspection image 8 at a position corresponding to the bright spot. Show. Since the third region 823 does not exist in the vicinity of the first region 821, the pass / fail judgment unit 752 has a non-ejection failure in which the treatment liquid is not ejected at the ejection port corresponding to the first region 821. Determined. The occurrence of the ejection failure is notified to an operator or the like through the notification unit 79 (see FIG. 4).

  As described above, the quality determination unit 752 detects the first area 821 (that is, the area where the image of the bright spot 81 exists in the reference image 732 but does not exist on the inspection image 9) on the difference image 82. Then, paying attention to the first area 821, the third area 823 (that is, the image of the bright spot 81 exists on the inspection image 9 in the vicinity thereof, like the first area 821 on the left side of the difference image 82, but the reference image It is searched whether or not a region that does not exist on 732 is detected. When the quality determination unit 752 finds the third region 823, it is determined that a discharge failure of oblique discharge has occurred at the discharge port corresponding to the first region 821. On the other hand, as in the first area 821 on the right side of the difference image 82, if the third area 823 is not found in the vicinity of the focused first area 821 by the quality determination unit 752, the first area 821 is displayed. It is determined that a non-ejection ejection failure has occurred at the corresponding ejection port.

  In addition, when an isolated third region 823 is found in which the first region 821 does not exist in the surrounding area, the discharge port corresponding to the third region 823 was not operating when the reference image 732 was acquired. When the inspection image 8 was picked up, water droplets or the like were attached to the image pickup unit 52, or the image displacement correction of the inspection image 8 by the position displacement correction unit 751 was not performed correctly. there is a possibility. Therefore, even when such an isolated third region 823 is found, it is possible to notify an operator or the like through the notification unit 79 (see FIG. 4).

  By the way, as a discharge inspection unit that determines the quality of the discharge operation at a plurality of discharge ports, it is possible to acquire an inspection image similar to the above and measure the interval in the arrangement direction of a plurality of bright spots on the inspection image. In such a discharge inspection section (hereinafter referred to as “discharge inspection section of the first comparative example”), it is determined that the discharge operation at each discharge port is good if the interval between the plurality of bright spots is approximately equal to the predetermined interval. Is done. On the other hand, when the interval between two adjacent bright spots is at least twice as large as the predetermined interval, it is determined that a non-discharge outlet exists between the two outlets corresponding to the two bright spots.

  In the discharge inspection unit of the first comparative example, when there are two adjacent bright spots that are larger (or smaller) than the predetermined gap to some extent, among the two discharge ports corresponding to the two bright spots, It is determined that an oblique discharge failure has occurred in either one or both. However, it is not easy to determine which of the two discharge ports has a discharge failure. In addition, when the processing liquid from one discharge port is shifted away from the other discharge port and the processing liquid from the other discharge port is shifted away from one discharge port, the processing liquid from each discharge port Even if the deviation is within the allowable range, as described above, at least one of the two discharge ports is erroneously determined as a discharge failure. Further, when a discharge failure occurs in a plurality of continuous discharge ports, and the plurality of bright spots corresponding to the plurality of discharge ports are shifted by the same distance in the same direction, the interval between the plurality of bright spots is a predetermined interval. Since they are approximately equal, these ejection defects are not detected.

  On the other hand, the quality determination unit 752 of the determination unit 75 determines the quality of the ejection operation at each of the plurality of ejection ports 314a to 314d based on the difference between the reference image 732 and the inspection image 8. Thereby, the quality of the discharge operation in each of the plurality of discharge ports 314a to 314d can be accurately determined individually (that is, independently of the quality of the discharge operations of the other discharge ports 314a to 314d). In addition, it is possible to simplify the quality determination of the discharge operation. Further, the quality determination unit 752 obtains the difference between the reference image 732 and the inspection image 8 after correcting the image shift of the inspection image 8, and determines the quality of the ejection operation. Thereby, the positional deviation from the design inspection position of the discharge head 31 in the inspection region can be corrected, and the inspection accuracy of the discharge operation at the plurality of discharge ports 314a to 314d can be improved. As a result, it is possible to suppress or prevent an adverse effect on processing on the substrate 9 due to ejection failure. As the adverse effect, for example, the quality of the processing on the substrate 9 is deteriorated due to non-ejection of the processing liquid, and the pattern on the substrate 9 is damaged due to the oblique ejection of the processing liquid.

  In the ejection head 31, a large number of ejection ports 314a to 314d are provided and arranged as ejection port arrays 313a to 313d extending substantially linearly in the arrangement direction. Therefore, a large number of bright spots 81 are close to each other on the inspection image 8, and it is not easy to grasp the correspondence between each bright spot 81 and the discharge ports 314a to 314d. In the substrate processing apparatus 1, as described above, a plurality of bright spots on the reference image 732 having a clear correspondence relationship with the plurality of discharge ports 314 a to 314 d and a plurality of bright spots 81 on the inspection image 8 are associated with each other. As a result, the discharge operation of each of the discharge ports 314a to 314d can be determined with high accuracy individually, so that the structure of the substrate processing apparatus 1 is a discharge in a discharge head having a plurality of discharge port arrays arranged in parallel to each other. It is particularly suitable for determining the quality of operation.

  The substrate processing apparatus inspects the ejection operation based on the difference between the position of the normal bright spot obtained by calculation and the position of the bright spot on the inspection image instead of the above-described reference image 732 (hereinafter referred to as “the substrate processing apparatus”). "Substrate processing apparatus of the second comparative example") is also conceivable. The above-mentioned normal bright spot position is the bright spot position on the inspection image when it is assumed that the processing liquid is normally discharged from the discharge head, and is calculated based on the design data of the substrate processing apparatus. Is required. However, in the substrate processing apparatus of the second comparative example, the position of the bright spot on the inspection image due to tolerance at the time of manufacturing the discharge head (for example, positional deviation within the allowable range of the discharge port at the time of manufacturing the discharge head). Even if a deviation occurs, there is a possibility that the ejection failure is determined as oblique ejection. In addition, even if a bright spot is misaligned on the inspection image due to misalignment or misalignment within an allowable range when the light emitting unit or the imaging unit is installed, the ejection failure is considered as oblique ejection. May be judged. Originally, such a bright spot misalignment is not caused by oblique ejection, and therefore should not be determined as ejection failure.

  In contrast, in the substrate processing apparatus 1 shown in FIG. 1, the reference image 732 corresponding to the normal ejection state is acquired in the actually manufactured substrate processing apparatus 1. Therefore, the bright spot in the reference image 732 is located at a position reflecting the influence of the tolerance at the time of manufacturing the ejection head 31 as described above, the tolerance at the time of installing the light emitting unit 51 and the imaging unit 52, and the like. For this reason, when the quality of the ejection operation is determined based on the difference between the reference image 732 and the inspection image 8, the positional deviation of the bright spot 81 due to the above-described various tolerances is not detected as the above-described difference, and the tolerance etc. It is possible to prevent erroneous determination (for example, determination of oblique ejection) due to the above.

  In the substrate processing apparatus of the second comparative example, it is also conceivable to correct the above-described various tolerances after obtaining the position of a normal bright spot by calculation. However, in order to perform the correction, it is necessary to obtain an image corresponding to a normal discharge state, calculate a difference from the position of the bright spot obtained by calculation from design data or the like, and perform correction. A lot of work occurs in preparation for inspection. On the other hand, in the substrate processing apparatus 1 shown in FIG. 1, the preparation operation is completed only by acquiring an image corresponding to a normal ejection state and storing the image as the reference image 732 in the reference image storage unit 731. Thus, the substrate processing apparatus 1 can simplify the preparation work for the discharge inspection.

  In the substrate processing apparatus 1, as described above, the distance between one bright spot 81 on the inspection image 8 and the bright spot corresponding to the one bright spot 81 in the reference image 732 is obtained. When the distance is greater than the predetermined distance, it is determined that a discharge failure of oblique discharge has occurred at the discharge port corresponding to the bright spot 81. Thus, by determining whether the discharge direction of the processing liquid from the discharge port is within the allowable range or outside the allowable range, it is possible to accurately detect the discharge failure of the oblique discharge. In addition, since the predetermined distance becomes smaller as the bright spot 81 moves away from the imaging unit 52, it is possible to detect the ejection failure of the oblique ejection with higher accuracy.

  As described above, in the ejection inspection unit 5 of the substrate processing apparatus 1, the imaging direction in the imaging unit 52 is inclined with respect to a plane perpendicular to the predetermined ejection direction of the processing liquid from the ejection head 31. Accordingly, the imaging unit 52 can reliably acquire the inspection image 8 including the bright spots 81 corresponding to the liquid droplets from all the ejection ports 314a to 314d without arranging the imaging unit 52 immediately below the ejection port. it can. Furthermore, it is possible to prevent the plurality of bright spots 81 from overlapping each other on the inspection image 8. As a result, it is possible to improve the pass / fail judgment accuracy of the discharge operation at the plurality of discharge ports 314a to 314d. Such a structure of the discharge inspection unit 5 is particularly suitable for determining whether the discharge operation is good or not in a discharge head having a plurality of discharge port arrays arranged in parallel to each other.

  As described above, in the discharge inspection unit 5, the light existence surface is inclined with respect to a plane perpendicular to the predetermined discharge direction of the processing liquid. Thereby, it is possible to suppress the plurality of bright spots 81 from overlapping each other on the inspection image 8. As a result, it is possible to further improve the pass / fail judgment accuracy of the discharge operation at the plurality of discharge ports 314a to 314d. Such a structure of the discharge inspection unit 5 is also particularly suitable for determining whether the discharge operation is good or not in a discharge head having a plurality of discharge port arrays arranged in parallel to each other.

  As described above, the plurality of ejection ports 314a to 314d of the ejection head 31 include ejection port arrays 313a to 313d that extend substantially linearly in the arrangement direction and are arranged in a direction inclined with respect to the arrangement direction. For this reason, even when the ejection ports at the end of one ejection port array are non-ejection, the distance corresponding to the arrangement pitch of the inspection image 8 on the non-ejection ejection port side when detecting image misalignment Thus, it is prevented that the difference between the inspection image 8 and the reference image 732 is determined to be the smallest at a position shifted from the reference image 732 only. Thereby, the image shift amount of the inspection image 8 can be acquired with higher accuracy.

  Various changes can be made in the substrate processing apparatus 1.

  In the quality determination unit 752 of the determination unit 75, the difference image 82 does not necessarily need to be generated, and quality of the discharge operation at the plurality of discharge ports 314a to 314d is determined based on the difference between the reference image 732 and the inspection image 8. If it is, the pass / fail determination may be performed by various methods.

  In the above description, the non-ejection and oblique ejection of the processing liquid are determined as ejection failures by the pass / fail determination unit 752, but other ejection operations may also be determined as ejection failures. For example, there is a possibility that droplets ejected from the ejection head 31 are split during flight and become a plurality of extremely small droplets. Such a very small droplet cannot give sufficient kinetic energy to the upper surface 91 of the substrate 9, and the substrate 9 may not be cleaned properly. Therefore, the discharge of such a small droplet may also be determined as a discharge failure at the discharge port. In the case where it is determined that the discharge of a very small droplet is a discharge failure, for example, in the difference image 82, a case where a third region 823 smaller than normal is detected in the vicinity of the first region 821 is determined as a discharge failure.

  In the light emission part 51, it is not always necessary to emit light in a planar shape. Light extending linearly forward from the light emission part 51 is emitted along the light existence surface, and the light is emitted along the light existence surface. You may scan by optical scanning means, such as a polygon mirror. Accordingly, when the plurality of flying bodies that are the processing liquids discharged from the plurality of discharge ports 314a to 314d pass through the light existence surface, the plurality of flying bodies are irradiated with light. The light existence surface may be perpendicular to the designed ejection direction of the processing liquid from the ejection head 31, and the imaging direction in the imaging unit 52 is parallel to a plane perpendicular to the designed ejection direction. May be.

  The light emitting unit 51 and the imaging unit 52 may be disposed at a position other than the diagonally lower side of the ejection head 31, for example, the diagonally upper side of the ejection head 31. The above-described inspection area may be set in an area other than above the standby pod 4. In this case, the light emission part 51 and the imaging part 52 are arrange | positioned in the vicinity of the said test | inspection area | region.

  The plurality of discharge ports of the discharge head 31 do not necessarily need to include a plurality of discharge port arrays arranged in parallel to each other.

  The substrate processing apparatus 1 may be used for various processes other than the cleaning of the substrate 9. Moreover, in the substrate processing apparatus 1, you may utilize for the process of the glass substrate used for display apparatuses other than a semiconductor substrate, such as a liquid crystal display device, a plasma display, and FED (field emission display). Alternatively, the substrate processing apparatus 1 may be used for processing of an optical disk substrate, a magnetic disk substrate, a magneto-optical disk substrate, a photomask substrate, a ceramic substrate, a solar cell substrate, and the like.

  The apparatus including the light emitting unit 51, the imaging unit 52, the reference image storage unit 731, and the determination unit 75 may be used as a discharge inspection apparatus that is independent from other configurations of the substrate processing apparatus 1. The discharge inspection apparatus is used for, for example, inspecting the operation of discharging liquid from a plurality of discharge ports in an apparatus that discharges liquid from a plurality of discharge ports to the various substrates described above.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Substrate processing apparatus 5 Discharge inspection part 8 Inspection image 9 Substrate 21 Substrate holding part 31 Discharge head 51 Light emitting part 52 Imaging part 75 Judgment part 81 Bright spot 82 Difference image 313a-313d Discharge port row 314a-314d Discharge port 510 Planar shape Light 731 Reference image storage unit 732 Reference image 751 Position shift correction unit 752 Pass / fail judgment unit

Claims (8)

A discharge inspection device for inspecting the discharge operation of liquid from a plurality of discharge ports,
By emitting planar light along a predetermined light existence surface, a plurality of flying bodies that are liquids ejected from a plurality of ejection openings pass to the plurality of flying bodies when passing through the light existence surface. A light emitting part for irradiating light;
An imaging unit for acquiring an inspection image including a plurality of bright spots appearing on the plurality of flying objects by imaging the plurality of flying objects passing through the light existence surface;
A reference image storage unit that stores a reference image that is an image acquired by the imaging unit while emitting light from the light emitting unit in a state in which liquid is normally ejected from the plurality of ejection ports;
A determination unit that determines the quality of the discharge operation at the plurality of discharge ports based on a difference between the reference image and the inspection image;
Equipped with a,
An ejection inspection apparatus, wherein an imaging direction in the imaging unit is inclined with respect to a plane perpendicular to a predetermined ejection direction of the plurality of flying objects. A discharge inspection device for inspecting the discharge operation of liquid from a plurality of discharge ports,
By emitting planar light along a predetermined light existence surface, a plurality of flying bodies that are liquids ejected from a plurality of ejection openings pass to the plurality of flying bodies when passing through the light existence surface. A light emitting part for irradiating light;
An imaging unit for acquiring an inspection image including a plurality of bright spots appearing on the plurality of flying objects by imaging the plurality of flying objects passing through the light existence surface;
A reference image storage unit that stores a reference image that is an image acquired by the imaging unit while emitting light from the light emitting unit in a state in which liquid is normally ejected from the plurality of ejection ports;
A determination unit that determines the quality of the discharge operation at the plurality of discharge ports based on a difference between the reference image and the inspection image;
Equipped with a,
The discharge inspection apparatus, wherein the light existence surface is inclined with respect to a plane perpendicular to a predetermined discharge direction of the plurality of flying objects.   The discharge inspection apparatus according to claim 1 or 2,
  The ejection inspection apparatus, wherein the inspection image is a still image of one frame. A discharge inspection device for inspecting the discharge operation of liquid from a plurality of discharge ports,
By emitting planar light along a predetermined light existence surface, a plurality of flying bodies that are liquids ejected from a plurality of ejection openings pass to the plurality of flying bodies when passing through the light existence surface. A light emitting part for irradiating light;
An imaging unit that obtains an inspection image that is a still image of one frame including a plurality of bright spots appearing on the plurality of projectiles by imaging the plurality of projectiles passing through the light existence plane;
A reference image storage unit that stores a reference image that is an image acquired by the imaging unit while emitting light from the light emitting unit in a state in which liquid is normally ejected from the plurality of ejection ports;
A determination unit that determines the quality of the discharge operation at the plurality of discharge ports based on a difference between the reference image and the inspection image;
A discharge inspection apparatus comprising: The discharge inspection apparatus according to any one of claims 1 to 4,
The discharge inspection apparatus, wherein the plurality of bright spots are extracted by performing binarization processing on the inspection image. A discharge inspection apparatus according to any one of claims 1 to 5 ,
The plurality of discharge ports include a plurality of discharge port arrays each of which is a set of discharge ports arranged linearly in the discharge port arrangement direction,
The discharge inspection apparatus, wherein the plurality of discharge port arrays are arranged in a direction inclined with respect to the discharge port arrangement direction. The discharge inspection apparatus according to any one of claims 1 to 6 ,
When the distance between one bright spot in the inspection image and a bright spot corresponding to the one bright spot in the reference image is larger than a predetermined distance, the determination unit determines that the one bright spot is A discharge inspection apparatus that determines that oblique discharge has occurred at a corresponding discharge port. A substrate processing apparatus,
A substrate holder for holding the substrate;
A discharge head that discharges liquid from a plurality of discharge ports toward the substrate and performs a predetermined process on the substrate;
A discharge inspection device according to any one of claims 1 to 7 for inspecting the discharge operation of liquid from the plurality of ejection ports of the ejection head,
A substrate processing apparatus comprising:

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