JP2013254817A - Laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a good protection film on a wafer without deteriorating the productivity.SOLUTION: A laser processing device includes: a laser processing unit (5) which performs ablation processing to a wafer (W) held by a chuck table (3); and a protection film coating device (6) forming a protection film (85) on a processing surface of the wafer (W) by a spin coating method. The protection film coating device (6) includes: an accommodating tank (61) accommodating a liquid resin (R); and a storage container (62) storing the liquid resin (R) at the downstream side of the accommodating tank (61) as a buffer. An air bubble removal filter (78) capturing air bubbles in the liquid resin (R) is provided in the storage container (62).

Description

  The present invention relates to a laser processing apparatus including a protective film coating apparatus that coats a processing surface of a wafer with a protective film.

  In a semiconductor device manufacturing process, division lines (streets) are formed in a lattice pattern on the surface of a wafer, and circuits such as ICs and LSIs are formed in regions partitioned by the division lines. The wafer is divided into individual device chips by cutting along a grid-like division line. The device chip thus divided is packaged and widely used in electric devices such as mobile phones and personal computers. As a method of dividing the wafer along the planned dividing line, a method of dividing the wafer by laser processing is adopted for reasons such as reduction of chipping.

  By the way, in laser processing, there has been a problem that debris is scattered by the thermal energy of laser light and adheres to the surface of the wafer, thereby degrading the quality of the device chip. Therefore, a laser processing apparatus that covers the surface of a wafer with a protective film before laser processing has been proposed (see, for example, Patent Document 1). In the laser processing apparatus of Patent Document 1, a liquid resin is supplied from a supply nozzle to a wafer on a spinner table, and a protective film is formed on the wafer surface by a so-called spin coating method. Thereafter, the laser beam is irradiated through the protective film, thereby preventing debris from adhering directly to the surface of the wafer.

  Further, as this type of laser processing apparatus, there has been proposed an apparatus that includes a plurality of tanks in which liquid resin is stored and selectively switches the supply source of the liquid resin from the plurality of tanks (for example, Patent Document 2). reference). In the laser processing apparatus of Patent Document 2, a plurality of tanks are selectively connected to a supply nozzle, and when the amount of liquid resin in one of the tanks falls below a predetermined amount, another tank is connected to the supply nozzle. Is done. For this reason, without stopping the supply of the liquid resin, it is possible to replenish the liquid resin with respect to the tank whose liquid amount has decreased, or to replace the tank itself.

JP 2004-322168 A JP 2008-126302 A

  However, if bubbles are mixed in the liquid resin during liquid feeding from the tank to the supply nozzle, the liquid resin containing bubbles is supplied to the surface of the wafer. When a protective film is formed on the surface of the wafer in this state, a hole may be formed due to bubbles remaining in the protective film. If holes due to air bubbles are formed on the planned division line, there is a possibility that debris will adhere directly to the wafer surface through the holes during laser processing in the subsequent process, degrading the quality of the device chip. It was.

  This invention is made | formed in view of this point, and it aims at providing the laser processing apparatus which can form a favorable protective film with respect to a wafer, without reducing productivity.

  The laser processing apparatus of the present invention includes a chuck table for holding a wafer, laser light irradiation means for irradiating the wafer held on the chuck table with laser light, and a protective film coating for covering the processed surface of the wafer with a protective film. The protective film coating apparatus includes a holding table for holding a wafer, a liquid resin nozzle for dropping a liquid resin on a processing surface of the wafer held by the holding table, The liquid resin supply means communicates with the liquid resin nozzle. The liquid resin supply means includes at least one storage tank that stores the liquid resin, and a storage container that stores the liquid resin stored in the storage tank. A first delivery pump for delivering a liquid resin from the storage tank to the storage container, and the liquid from the storage container A second delivery pump for delivering the liquid resin to the resin nozzle, and a control unit for controlling the first delivery pump and the second delivery pump, and the flow of the liquid resin in the storage container An air bubble removing filter that is disposed across the side surface and the bottom surface of the storage container in a direction substantially perpendicular to the direction and is formed in a flat plate shape and has a mesh-like air bubble capturing portion for capturing air bubbles in the liquid resin is provided. The inside of the pipe connecting the outlet of the storage container and the liquid resin nozzle is filled with a liquid resin from which bubbles are removed.

  According to this configuration, the storage container can function as a buffer tank by replenishing the storage container with the liquid resin from the storage tank. Therefore, even when the remaining amount of liquid resin in the storage tank is reduced and replacement work of the storage tank occurs, the protective film is applied to the wafer by the liquid resin in the storage container without stopping the protective film coating apparatus. Can be formed. Further, the liquid resin from which the bubbles are removed is sent from the storage container to the liquid resin nozzle by the bubble removal filter provided in the storage container. For this reason, since the inside of the pipe connecting the storage container and the liquid resin nozzle is filled with the liquid resin from which bubbles are removed, the liquid resin mixed with bubbles is not dropped from the liquid resin nozzle onto the wafer. Therefore, bubbles do not remain in the protective film, and the surface of the wafer can be covered with a good protective film.

  The laser processing apparatus of the present invention further includes a storage tank remaining amount sensor that detects that the liquid resin stored in the storage tank falls below a predetermined liquid amount, and the control unit includes the storage tank remaining amount. When the detection signal from the sensor is input, the notifying means is notified that the amount of liquid is below a predetermined amount.

  According to the present invention, a protective film is formed on the processed surface of the wafer without reducing productivity by providing a storage container, and the liquid resin from which bubbles are removed by the bubble removal filter is supplied to the liquid nozzle. Thus, the processed surface of the wafer can be covered with a good protective film.

It is a perspective view of the laser processing apparatus which concerns on this Embodiment. It is a perspective view of the protective film coating apparatus which concerns on this Embodiment. It is a schematic diagram of the piping structure and control structure of the liquid resin supply part concerning this Embodiment. It is explanatory drawing of the flow of protective film formation by the protective film coating apparatus concerning this Embodiment.

  Hereinafter, a laser processing apparatus according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of the laser processing apparatus according to the present embodiment. In FIG. 1, in the laser processing apparatus, a protective film coating apparatus that covers the processed surface of the wafer with a protective film is omitted. Further, the laser processing apparatus according to the present embodiment is not limited to the configuration shown in FIG. The laser processing apparatus may be configured in any way as long as it includes a protective film coating apparatus.

  As shown in FIG. 1, the laser processing apparatus 1 processes the wafer W by relatively moving a laser processing unit 5 (laser light irradiation means) for irradiating laser light and a chuck table 3 holding the wafer W. It is configured. The wafer W is formed in a substantially disc shape, and is partitioned into a plurality of regions by division lines arranged in a lattice pattern on the surface, and various devices are formed in the partitioned regions. A protective film 85 for suppressing adhesion of debris during laser processing is formed on the surface (processed surface) of the wafer W.

The wafer W is bonded to a dicing sheet 87 stretched on the ring frame 86 with the surface facing upward. In the present embodiment, a semiconductor wafer such as a silicon wafer or a gallium strain is described as an example of the wafer W, but the present invention is not limited to this configuration. Adhesive members such as DAF (Die Attach Film) provided on the backside of semiconductor wafers, semiconductor product packages, ceramics, glass, sapphire (Al ₂ O ₃ ) based inorganic material substrates, various electrical components and micron-order processing position accuracy Various processing materials that are required may be used as the wafer W.

  The laser processing apparatus 1 has a rectangular parallelepiped base 2. A chuck table moving mechanism 4 is provided on the upper surface of the base 2 to process and feed the chuck table 3 in the X-axis direction and index and feed it in the Y-axis direction. A standing wall portion 11 is erected on the rear side of the chuck table moving mechanism 4. An arm portion 12 projects from the front surface of the standing wall portion 11, and a laser processing unit 5 is supported on the arm portion 12 so as to face the chuck table 3.

  The chuck table moving mechanism 4 has a pair of guide rails 15 arranged on the upper surface of the base 2 and parallel to the X-axis direction, and a motor-driven X-axis table 16 slidably installed on the pair of guide rails 15. doing. The chuck table moving mechanism 4 includes a pair of guide rails 17 arranged on the top surface of the X-axis table 16 and parallel to the Y-axis direction, and a motor-driven Y-axis table 18 slidably installed on the pair of guide rails 17. And have.

  The chuck table 3 is provided on the Y-axis table 18. Note that nut portions (not shown) are formed on the back surfaces of the X-axis table 16 and the Y-axis table 18, respectively, and ball screws 21 and 22 are screwed to these nut portions. Then, the drive motors 23 and 24 connected to one end portions of the ball screws 21 and 22 are rotationally driven, whereby the chuck table 3 is moved along the guide rails 15 and 17 in the X-axis direction and the Y-axis direction.

  The chuck table 3 is formed in a disk shape, and is rotatably provided on the upper surface of the Y-axis table 18 via the θ table 25. An adsorption chuck is formed of a porous material on the upper surface of the chuck table 3. Around the chuck table 3, four clamp portions 26 are provided via a pair of support arms. When the four clamp portions 26 are driven by the air actuator, the ring frame 86 around the wafer W is clamped and fixed from four directions.

  The laser processing unit 5 has a processing head 31 provided at the tip of the arm portion 12. An optical system of the laser processing unit 5 is provided in the arm unit 12 and the processing head 31. The processing head 31 condenses laser light oscillated from an oscillator (not shown) by a condensing lens, and laser-processes the wafer W held on the chuck table 3. The laser beam has a wavelength that has an absorptivity with respect to the wafer W, and is adjusted so as to be focused on the surface (processed surface) of the wafer W in the optical system.

  In this case, the surface of the wafer W is covered with a protective film 85 formed in a protective film coating apparatus 6 (see FIG. 2) described later. By irradiating the surface of the wafer W with the laser light from the processing head 31 through the protective film 85, the surface of the wafer W is ablated and partially etched. At this time, since the protective film 85 is formed on the surface of the wafer W, debris scattered by ablation adheres to the protective film 85 and does not directly adhere to the surface of the wafer W.

  Then, the chuck table 3 is moved relative to the processing head 31 by the chuck table moving mechanism 4, so that laser processing (ablation processing) is performed along the division lines of the wafer W. Here, ablation means that when the irradiation intensity of the laser beam exceeds a predetermined processing threshold, it is converted into electronic, thermal, photochemical and mechanical energy on the solid surface, resulting in neutral atoms, molecules, positive and negative Ions, radicals, clusters, electrons, and light are explosively emitted and the solid surface is etched.

  With reference to FIG. 2, a protective film coating apparatus for coating the surface of a wafer with a protective film will be described. FIG. 2 is a perspective view of the protective film coating apparatus according to the present embodiment. Note that the protective film coating apparatus according to the present embodiment is not limited to the spin coat apparatus shown in FIG. The protective film coating apparatus may have any configuration as long as the protective film is formed by supplying a liquid resin to the surface of the wafer.

  As shown in FIG. 2, the protective film coating apparatus 6 supplies the liquid resin R to the wafer W on the holding table 41, and the liquid resin is applied to the entire surface of the wafer W by the centrifugal force accompanying the rotation of the holding table 41. It is configured to apply R. The protective film coating apparatus 6 has a bottomed cylindrical casing 37 composed of a cylindrical peripheral wall portion 35 and a bottom wall portion 36. The casing 37 is supported on the installation surface 39 by a plurality of (three in this embodiment) leg portions 38 extending from the lower surface of the bottom wall portion 36. A holding table 41 is accommodated in the casing 37, and a liquid resin nozzle 42, a washing water nozzle 43, and an air nozzle 44 are provided around the holding table 41.

  The holding table 41 is formed to have a larger diameter than the ring frame 86 of the wafer W, and an adsorption chuck is formed on the upper surface with a porous material. The suction chuck is connected to a suction source through a pipe (not shown) in the holding table 41, and sucks and holds the wafer W by a negative pressure generated on the suction chuck. At the center of the lower surface of the holding table 41, the upper end portion of the drive shaft 46 of the electric motor 45 is fixed. The drive shaft 46 extends upward from the electric motor 45 located below the casing 37 and is connected to the holding table 41 through a central opening formed through the bottom wall portion 36.

  A plurality (three in this embodiment) of air cylinders 48 are attached to the outer peripheral surface of the electric motor 45. The electric motor 45 is supported by a piston rod 47 abutted against the installation surface 39 from each air cylinder 48, and is driven up and down by the expansion and contraction of the piston rod 47. In this way, the holding table 41 is rotated at a high speed in the casing 37 by the electric motor 45, and is driven up and down between a raised position where the wafer W is taken in and a lowered position where processing is performed by the plurality of air cylinders 48.

  The liquid resin nozzle 42 is formed in a substantially L shape with a horizontal portion 51 extending horizontally above the holding table 41 and a vertical portion 52 extending downward from the base end of the horizontal portion 51. The front end portion of the horizontal portion 51 is bent downward, and the liquid resin R is dropped onto the wafer W on the holding table 41 from the bent front end portion. Further, the liquid resin nozzle 42 is supported by the casing 37 so as to be rotatable above the holding table 41. The liquid resin R is supplied to the liquid resin nozzle 42 from a liquid resin supply unit 8 (liquid resin supply means) described later.

  In the protective film coating apparatus 6, when the liquid resin R is dropped from the liquid resin nozzle 42 onto the center of the surface of the wafer W, the holding table 41 rotates at a high speed, so that centrifugal force acts on the liquid resin R. By this centrifugal force, the liquid resin R is spread over the entire surface of the wafer W, and a protective film 85 is formed (see FIG. 4C). The wafer W on which the protective film 85 is formed is transferred to the chuck table 3 and laser processing is performed. At the time of laser processing, since the surface of the wafer W is covered with the protective film 85 as described above, debris does not directly adhere to the surface of the wafer W.

  As the liquid resin R, for example, a water-soluble resin such as polyvinyl alcohol (PVA) or polyethylene glycol (PEG) is dropped onto the wafer W. In addition, it is preferable to add to the liquid resin R an absorbent that absorbs light having a laser wavelength. As a result, the protective film 85 is also removed simultaneously with the processing of the wafer W during laser processing, so that the protective film 85 is prevented from being peeled off from the surface of the wafer W by the vapor of the thermal decomposition product of the wafer W.

  Further, the protective film coating apparatus 6 not only forms the protective film 85 on the unprocessed wafer W, but also functions as a cleaning apparatus that removes the protective film 85 from the processed wafer W. In the casing 37, similarly to the liquid resin nozzle 42, a washing water nozzle 43 and an air nozzle 44 are provided so as to be able to turn. The washing water nozzle 43 and the air nozzle 44 are respectively provided with horizontal portions 53 and 55 extending horizontally above the holding table 41 and a vertical portion 54 extending downward from the base ends of the horizontal portions 53 and 55 (the vertical portion of the air nozzle 44 is (Not shown). The tip portions of the cleaning water nozzle 43 and the air nozzle 44 are bent downward, respectively, and cleaning water and dry air are sprayed onto the wafer W from the bent tip portions.

  At the time of cleaning the protective film coating apparatus 6, the processed wafer W is held on the holding table 41, and the holding table 41 is rotated at high speed while jetting cleaning water from the cleaning water nozzle 43. By spraying cleaning water onto the surface of the wafer W, the protective film 85 to which debris has adhered is washed away from the processed wafer W. Waste liquid at the time of cleaning is discharged through a drain hose 58 connected to the casing 37. Thereafter, the wafer W is dried by blowing dry air from the air nozzle 44 to the rotating wafer W.

  With reference to FIG. 3, the flow path structure and control structure of a liquid resin supply part are demonstrated. FIG. 3 is a schematic diagram of the pipe configuration and control configuration of the liquid resin supply unit according to the present embodiment. In addition, the liquid resin supply part concerning this Embodiment is not limited to the structure shown in FIG. The liquid resin supply unit may have any configuration as long as the liquid resin delivered from the storage tank to the liquid resin nozzle is temporarily stored in a storage container that functions as a buffer tank.

  As shown in FIG. 3, the liquid resin supply unit 8 includes a storage tank 61 that stores the liquid resin R as a main tank, and a storage container 62 that stores the liquid resin R as a buffer tank downstream of the storage tank 61. Yes. The storage tank 61 is connected to the storage container 62 through the first pipe 63, and the storage container 62 is connected to the liquid resin nozzle 42 through the second pipe 64. A first delivery pump 65 for delivering the liquid resin R from the storage tank 61 to the storage container 62 is provided in the middle of the first pipe 63. A second delivery pump 66 for delivering the liquid resin R from the storage container 62 to the liquid resin nozzle 42 is provided in the middle of the second pipe 64. Further, the liquid resin supply unit 8 is comprehensively controlled by the control unit 9.

  The storage tank 61 is formed in a box shape, and is provided with a first delivery pipe 67 for delivering the liquid resin R in the tank. One end of the first delivery pipe 67 is positioned near the bottom surface 68 of the storage tank 61, and the other end is connected to the first pipe 63. The storage tank 61 is provided with an air communication portion (not shown) that communicates the inside of the tank with the air. A storage tank remaining amount sensor 69 is provided in the storage tank 61 at a position slightly higher than one end (lower end) of the first delivery pipe 67. The storage tank remaining amount sensor 69 is connected to the control unit 9, detects that the liquid resin R in the tank has fallen below a predetermined liquid amount, and notifies the control unit 9.

  The storage container 62 is formed in a box shape whose upper surface is open to the atmosphere, and an introduction pipe 71 for introducing the liquid resin R into the container and a second delivery pipe 72 for sending the liquid resin R in the container. Is provided. The second delivery pipe 72 functions as a delivery outlet in the storage container 62. One end of the introduction pipe 71 protrudes into the container from the side surface 73 on the right side of the page, and the other end is connected to the first pipe 63. One end of the second delivery pipe 72 is positioned near the bottom surface 75 of the storage container 62 on the side surface 74 side on the left side of the paper, and the other end is connected to the second pipe 64. A first detection sensor 76 is provided above the storage container 62. A second detection sensor 77 is provided below the storage container 62 at a position slightly higher than one end (lower end) of the second delivery pipe 72.

  The first detection sensor 76 is connected to the control unit 9, detects the upper limit liquid level position P <b> 1 of the liquid resin R in the container, and notifies the control unit 9. The second detection sensor 77 is connected to the control unit 9, detects the lower limit liquid level position P <b> 2 of the liquid resin R in the container, and notifies the control unit 9. In the storage container 62, a plurality of (three in the present embodiment) bubble removal filters 78 formed in a flat plate shape straddle the side surface of the storage container 62 on the front side, the rear side surface, and the bottom surface 75. It is arranged. The plurality of bubble removal filters 78 are arranged in parallel in an upright posture raised in a substantially vertical direction with respect to the flow direction of the liquid resin flowing from the side surface 73 toward the side surface 74 of the storage container 62.

  Each bubble removal filter 78 has a mesh-like bubble capturing portion 79 for capturing bubbles in the liquid resin R. When the liquid resin flows from the side surface 73 toward the side surface 74 in the storage container 62, the liquid resin R passes through the bubble capturing portion 79, so that the bubbles in the liquid resin R are removed. In addition, the bubble capture | acquisition part 79 should just be able to capture the bubble in liquid resin R, may be formed in planar shape, and may be formed in pleat shape. Further, the size and number of meshes of the bubble capturing unit 79 are set according to the concentration of the liquid resin R, the delivery speed, and the delivery amount. For example, when the transmission amount is large, the mesh is set large.

  In the present embodiment, each bubble removal filter 78 is provided in a substantially vertical direction with respect to the flow direction of the liquid resin R. However, the substantially vertical direction is not limited to a complete vertical direction, and an error in mounting accuracy occurs. This means that the width is increased accordingly. That is, the direction substantially perpendicular to the flow direction of the liquid resin R includes a level that can be regarded as being substantially perpendicular to the flow direction of the liquid resin R. In addition, one bubble supplement part 79 may be provided in one bubble removal filter 78, or a plurality of bubble supplement parts 79 may be provided according to the concentration of the liquid resin R or the like.

  The first and second delivery pumps 65 and 66 are connected to the control unit 9 and are driven by the control of the control unit 9. When the first delivery pump 65 is driven by the control unit 9, the liquid resin R is pumped from the vicinity of the bottom surface 68 of the storage tank 61 by the first delivery pipe 67 and directed toward the storage container 62 through the first pipe 63. Liquid resin R is delivered. When the second delivery pump 66 is driven by the control unit 9, the liquid resin R is pumped from the vicinity of the bottom surface 75 of the storage container 62 by the second delivery pipe 72 and directed toward the liquid resin nozzle 42 through the second pipe 64. Thus, the liquid resin R is delivered.

  The controller 9 controls the drive timing of the first and second delivery pumps 65 and 66 and monitors the remaining amount of the liquid resin R in the storage tank 61. The control unit 9 is connected to a notification unit 81 (notification unit) for prompting the replenishment of the liquid resin R into the storage tank 61. The control unit 9 includes a processor that executes various processes, a memory, and the like. The memory is composed of one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the application. The memory stores a control program for controlling operations of the first and second delivery pumps 65 and 66, the notification unit 81, and the like.

  The controller 9 drives the first delivery pump 65 according to the detection signal input from the first detection sensor 76, and the first delivery pump according to the detection signal input from the second detection sensor 77. 65 is stopped. Therefore, when the liquid level of the liquid resin R in the storage container 62 falls to the lower limit liquid level position P2, the liquid resin R from the storage tank 61 into the storage container 62 until the liquid level of the liquid resin R reaches the upper limit liquid level position P1. Is replenished. In this way, a certain amount or more of the liquid resin R is secured in the storage container 62. Further, since the lower limit liquid surface position P2 is higher than one end (lower end) of the second delivery pipe 72, one end of the second delivery pipe 72 is always immersed in the liquid, Air does not get into.

  The control unit 9 drives and controls the second delivery pump 66 so as to send out the liquid resin R according to the coating amount of the liquid resin R dripped onto the wafer W from the liquid resin nozzle 42. By driving the second delivery pump 66, a flow of the liquid resin R from the side surface 73 toward the side surface 74 is generated in the storage container 62, and the liquid resin R passes through the plurality of bubble removal filters 78, thereby causing bubbles in the liquid. Is captured by the bubble capturing unit 79. For this reason, the liquid resin R from which bubbles are removed is sucked into the second delivery pipe 72. Therefore, the downstream side of the storage container 62, that is, the second delivery pipe 72, the second pipe 64, and the liquid resin nozzle 42 are always filled with the liquid resin R from which bubbles are removed.

  In response to the detection signal input from the storage tank remaining amount sensor 69, the control unit 9 causes the notification unit 81 to notify that the remaining amount of the liquid resin R in the storage tank 61 has fallen below a predetermined liquid amount. Note that the notification unit 81 notifies at least one of voice notification, light emission notification, and display notification. The notification of the notification unit 81 prompts the operator to replace the storage tank 61 or refill the liquid resin. At this time, since the storage container 62 functions as a buffer tank of the storage tank 61, productivity can be improved without stopping the protective film coating apparatus 6 even when the storage tank 61 is being replaced. ing.

  Next, with reference to FIG. 4, the flow of protective film formation by the protective film coating apparatus will be described. FIG. 4 is an explanatory diagram of a flow of forming a protective film by the protective film coating apparatus according to the present embodiment. In FIG. 4, for the convenience of explanation, the protective film coating apparatus is shown in a simplified manner.

  As shown in FIG. 4A, when the wafer W is placed on the holding table 41, the wafer W is held by the suction chuck, and the holding table 41 moves to the lowered position in the casing 37. Then, the liquid resin nozzle 42 rotates and the tip portion of the nozzle is positioned at the center of the wafer W. Next, as shown in FIG. 4B, the second delivery pump 66 is driven by the control unit 9, and the liquid resin R is dropped from the liquid resin nozzle 42 onto the wafer W, and the liquid is collected in the center of the surface of the wafer W. R1 is formed.

  At this time, the liquid resin R in the storage container 62 is supplied to the liquid resin nozzle 42 through the plurality of bubble removal filters 78. Since the liquid resin nozzle 42 and the second pipe 64 are filled with the liquid resin R from which bubbles are removed, the liquid resin R mixed with bubbles is dropped from the liquid resin nozzle 42 onto the wafer W. There is no. When a predetermined amount of the liquid resin R is dropped from the liquid resin nozzle 42 onto the wafer W, the control unit 9 stops the second delivery pump 66. Then, the liquid resin nozzle 42 turns and the tip portion of the nozzle is removed from above the wafer W.

  Next, as shown in FIG. 4C, the holding table 41 holding the wafer W rotates at high speed. Thereby, a centrifugal force acts on the liquid reservoir R1 of the liquid resin R at the center of the upper surface of the wafer W, and the liquid resin R is spread so as to cover the entire upper surface of the wafer W. As the liquid resin R solidifies, a protective film 85 is formed on the upper surface of the wafer W. Since the bubbles in the liquid resin R are removed, no holes are formed by the bubbles remaining in the protective film 85, and a good protective film 85 is formed on the upper surface of the wafer W.

  When the protective film 85 is formed on the surface of the wafer W, the holding table 41 moves in the casing 37 to the raised position. Then, the wafer W is transferred from the holding table 41 to the chuck table 3 (see FIG. 1), and subsequent laser processing is performed. The laser-processed wafer W is again carried into the protective film coating apparatus 6 and the protective film 85 to which debris is attached is washed away.

  As described above, according to the laser processing apparatus 1 according to the present embodiment, the storage container 62 can function as a buffer tank by replenishing the storage container 62 with the liquid resin R from the storage tank 61. Therefore, even when the remaining amount of the liquid resin R in the storage tank 61 is reduced and the replacement operation of the storage tank 61 occurs, the liquid resin in the storage container 62 is not stopped without stopping the protective film coating apparatus 6. The protective film 85 can be formed on the wafer W by R. Further, the liquid resin R from which the bubbles are removed is sent from the storage container 62 to the liquid resin nozzle 42 by the bubble removal filter 78 provided in the storage container 62. For this reason, since the inside of the second pipe 64 that connects the storage container 62 and the liquid resin nozzle 42 is filled with the liquid resin R from which bubbles are removed, the liquid resin R in which bubbles are mixed is transferred from the liquid resin nozzle 42 to the wafer W. It is not dripped with respect to. Therefore, no bubbles remain in the protective film 85, and the surface of the wafer W can be covered with the good protective film 85.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the first and second detection sensors 76 and 77 are provided in the storage container 62, and the storage container 61 is moved from the storage tank 61 according to the detection of the first and second detection sensors 76 and 77. Although the liquid resin R is replenished to 62, it is not limited to this structure. If the liquid resin R is periodically replenished from the storage tank 61 to the storage container 62, the first and second detection sensors 76 and 77 may not be provided in the storage container 62. Further, the replenishment timing of the liquid resin R from the storage tank 61 to the storage container 62 can be changed as appropriate.

  Moreover, in the said embodiment, although the liquid resin supply part 8 was set as the structure which has one each of the storage tank 61 and the storage container 62, it is not limited to this structure. The liquid resin supply unit 8 may include a plurality of storage tanks 61 and a plurality of storage containers 62.

  In the above embodiment, the introduction pipe 71 is provided on the side surface 73 of the storage container 62 and the second delivery pipe 72 is provided on the side surface 74. However, the present invention is not limited to this configuration. The introduction pipe 71 and the second delivery pipe 72 are provided at any positions as long as the liquid resin R introduced from the introduction pipe 71 is provided from the second delivery pipe 72 through the bubble removal filter 78. It may be done.

  Further, in the above-described embodiment, the storage container 62 may be configured to provide a partition with a gap between the bubble removal filter 78 and the introduction pipe 71 so as to remove larger bubbles from the liquid resin R. Good. In this case, it is only necessary to remove larger bubbles upstream of the bubble removal filter 78. For example, the larger bubbles may be removed by a filter having a coarse mesh.

  As described above, the present invention has an effect that a good protective film can be formed on a wafer without lowering the productivity, and in particular, ablation processing is performed along the division line. Useful for laser processing equipment.

DESCRIPTION OF SYMBOLS 1 Laser processing apparatus 3 Chuck table 5 Laser processing unit (laser beam irradiation means)
6 Protective film coating device 8 Liquid resin supply unit (liquid resin supply unit)
DESCRIPTION OF SYMBOLS 9 Control part 41 Holding table 42 Liquid resin nozzle 61 Storage tank 62 Storage container 63 1st piping 64 2nd piping (piping)
65 First delivery pump 66 Second delivery pump 69 Storage tank remaining amount sensor 76 First detection sensor 77 Second detection sensor 78 Bubble removal filter 79 Bubble capture portion 81 Notification portion 85 Protective film W Wafer R Liquid resin P1 Upper limit liquid level position P2 Lower limit liquid level position

Claims (2)

Laser processing comprising at least a chuck table for holding a wafer, laser light irradiation means for irradiating the wafer held by the chuck table with laser light, and a protective film coating apparatus for coating a processed surface of the wafer with a protective film A device,
The protective film coating apparatus includes: a holding table that holds a wafer; a liquid resin nozzle that drops liquid resin on a processed surface of the wafer held on the holding table; and a liquid resin supply unit that communicates with the liquid resin nozzle. Configured,
The liquid resin supply means includes at least one storage tank that stores the liquid resin, a storage container that stores the liquid resin stored in the storage tank, and a first container that sends the liquid resin from the storage tank to the storage container. One delivery pump, a second delivery pump for delivering the liquid resin from the storage container to the liquid resin nozzle, and a controller for controlling the first delivery pump and the second delivery pump. ,
In the storage container, a net-like shape is disposed across the side surface and the bottom surface of the storage container in a direction substantially perpendicular to the flow direction of the liquid resin and is formed in a flat plate shape for capturing bubbles in the liquid resin. A bubble removal filter having a bubble trapping portion is provided,
A laser processing apparatus, wherein a pipe connecting the outlet of the storage container and the liquid resin nozzle is filled with a liquid resin from which bubbles are removed. A storage tank remaining amount sensor for detecting that the liquid resin stored in the storage tank has fallen below a predetermined liquid amount;
2. The laser processing apparatus according to claim 1, wherein when the detection signal from the storage tank remaining amount sensor is input, the control unit causes the notification unit to notify that the amount of liquid is less than a predetermined amount.

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