KR20130137081A - Laser machining apparatus - Google Patents

Abstract

The purpose of the present invention is to form a protective layer favorable for a wafer without a decline in productivity. The present invention includes a laser machining unit (5) to perform ablation machining for a wafer (W) on a chuck table (3); and a protective layer coating device (6) to form a protective layer (85) on the machining surface of the wafer (W) with a spin-coating method. The protective layer coating device (6) includes an accepting tank (61) to store a liquefied resin (R); a storage container (62) to store the liquefied resin (R) at the bottom of the accepting tank (61) as a buffer; and a bubble removing filter (78) to capture bubbles contained in the liquefied resin (R) in the storage container. [Reference numerals] (42) Liquid resin nozzle;(81) Notification unit;(9) Control unit

Description

Laser processing device {LASER MACHINING APPARATUS}

TECHNICAL FIELD This invention relates to the laser processing apparatus provided with the protective film coating apparatus which coats the process surface of a wafer with a protective film.

In the manufacturing process of a semiconductor device, the division scheduled line (street) is formed in the grid | lattice form on the surface of a wafer, and circuits, such as IC and LSI, are formed in the area | region partitioned by the division scheduled line. The wafer is cut into individual device chips by cutting along a lattice scheduled division line. The device chips divided in this manner are packaged and widely used in electric devices such as mobile phones and personal computers. As a method of dividing a wafer along a division scheduled line, a method of dividing by a laser processing is also employed for reasons such as chipping reduction.

By the way, in laser processing, debris scattered by the thermal energy of laser light and adhered to the surface of the wafer, resulting in a problem of degrading device chip quality. Then, the laser processing apparatus which coat | covers the surface of a wafer with a protective film before laser processing is proposed (for example, refer patent document 1). In the laser processing apparatus of patent document 1, liquid resin is supplied to the wafer on a spinner table from a supply nozzle, and a protective film is formed in the surface of a wafer by what is called a spin coat method. Thereafter, laser light is irradiated through the protective film, whereby debris is prevented from adhering directly to the surface of the wafer.

In addition, as this type of laser processing apparatus, it is proposed to provide a plurality of tanks in which liquid resin is stored and to selectively switch the source of liquid resin in the plurality of tanks (see Patent Document 2, for example). In the laser processing apparatus of patent document 2, a some tank is selectively connected to a supply nozzle, and when the liquid amount of the liquid resin of any one tank falls below a predetermined quantity, another tank is connected to a supply nozzle. For this reason, it is possible to replenish the liquid resin or replace the tank itself with respect to the tank in which the liquid amount is lowered without stopping the supply of the liquid resin.

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-322168 Patent Document 2: Japanese Patent Application Laid-Open No. 2008-126302

However, if bubbles are mixed in the liquid resin during the liquid transfer from the tank to the supply nozzle, the liquid resin including the bubbles is supplied to the surface of the wafer. When a protective film is formed on the surface of a wafer in this state, a hole may arise by the bubble which remained in the protective film. In the case where holes due to bubbles are formed on the scheduled lines to be divided, there is a possibility that debris adheres directly to the surface of the wafer through the holes during laser processing in a subsequent step, which may deteriorate the quality of the device chip.

This invention is made | formed in view of such a point, Comprising: 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 at least a chuck table for holding a wafer, laser light irradiation means for irradiating a laser beam to a wafer held on the chuck table, and a protective film coating device for coating a processing 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 dropping liquid resin onto a processing surface of a wafer held on the holding table, and a liquid phase in communication with the liquid resin nozzle. The liquid resin supply means includes at least one accommodation tank for accommodating liquid resin, a storage container for storing liquid resin contained in the accommodation tank, and a liquid resin from the accommodation tank to the storage container. And a liquid resin from the storage container to the liquid resin nozzle. The delivery unit is composed of a second delivery pump, a control unit for controlling the first delivery pump and the second delivery pump, and in the storage container, the side and the bottom of the storage container in a direction substantially perpendicular to the flow direction of the liquid resin. A bubble removal filter is disposed over the surface and formed on the flat plate and has a bubble trapping portion having a mesh-like bubble trapping portion for trapping bubbles in the liquid resin, and the inside of the pipe connecting the outlet of the storage container and the liquid resin nozzle is bubbled. It is characterized in that the filled with the removed liquid resin.

According to this configuration, the liquid container is replenished from the storage tank to the storage container, whereby the storage container can function as a buffer tank. Therefore, even when the remaining amount of the liquid resin in the storage tank decreases and the replacement operation of the storage tank occurs, the protective film can be formed on the wafer by the liquid resin in the storage container without stopping the protective film coating apparatus. Moreover, the liquid resin from which the bubble was removed by the bubble removal filter provided in the storage container is sent from a storage container to a liquid resin nozzle. For this reason, since the inside of the piping which connects a storage container and a liquid resin nozzle is filled with the liquid resin from which the bubble was removed, the liquid resin in which bubble was mixed does not drop to a wafer from a liquid resin nozzle. Therefore, no bubbles remain in the protective film, and the surface of the wafer can be covered with a good protective film.

Moreover, the said laser processing apparatus of this invention is equipped with the accommodation tank residual amount sensor which detects that the liquid resin accommodated in the said accommodation tank is below the predetermined quantity, and the said control part has received the detection signal from the said storage tank residual amount sensor At that time, the notification means is informed that the amount is lower than the predetermined amount.

According to the present invention, by providing a storage container, a protective film is formed on the processed surface of the wafer without lowering the productivity, and the liquid resin from which bubbles are removed by the bubble removing filter is supplied to the liquid nozzle, thereby making the processed surface of the wafer a good protective film. Can be covered.

1 is a perspective view of a laser machining apparatus according to the present embodiment.
2 is a perspective view of a protective film coating device according to the present embodiment.
3 is a schematic diagram of a piping configuration and a control configuration of a liquid resin supply unit according to the present embodiment.
4 is an explanatory diagram of a protective film formation flow by the protective film coating device according to the present embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, the laser processing apparatus which concerns on this embodiment is demonstrated with reference to an accompanying drawing. 1 is a perspective view of a laser processing apparatus according to the present embodiment. In addition, in FIG. 1, the protective film coating apparatus which coat | covers the process surface of a wafer with a protective film is abbreviate | omitted and described in the laser processing apparatus. In addition, the laser processing apparatus which concerns on this embodiment is not limited to the structure shown in FIG. If the laser processing apparatus is equipped with the protective film coating apparatus, what kind of structure may be sufficient as it.

As shown in FIG. 1, the laser processing apparatus 1 relatively moves the laser processing unit 5 (laser light irradiation means) which irradiates a laser beam, and the chuck table 3 which hold | maintained the wafer W. FIG. It is comprised so that the wafer W may be processed. The wafer W is formed in a substantially disk shape, is partitioned into a plurality of areas by division scheduled lines arranged in a lattice shape on the surface, and various devices are formed in each of the divided areas. On the surface (processing surface) of the wafer W, a protective film 85 for suppressing adhesion of debris during laser processing is formed.

The wafer W is adhered to the dicing sheet 87 laid on the ring frame 86 with the surface upward. In addition, in this embodiment, although the semiconductor wafer, such as a silicon wafer and gallium arsenide, is demonstrated as an example as the wafer W, it is not limited to this structure. An adhesive member, such as DAF (Die Attach Film), which is installed on the back surface of the semiconductor wafer, a semiconductor product package, ceramic, glass, sapphire (Al ₂ 0 ₃₎ based inorganic material substrate, processing the position accuracy of the various electrical components and micron order of Various processing materials which are required may be used as the wafer (W).

The laser processing apparatus 1 has a rectangular parallelepiped base 2. On the upper surface of the base 2, a chuck table moving mechanism 4 for processing and conveying the chuck table 3 in the X axis direction and indexing and feeding the Y axis direction is provided. In the rear of the chuck table moving mechanism 4, the mouth wall part 11 is installed upright. The arm part 12 protrudes from the front surface of the mouth wall part 11, and the laser processing unit 5 is supported by the arm part 12 so that the chuck table 3 may be opposed.

The chuck table moving mechanism 4 is provided with a pair of guide rails 15 arranged on an upper surface of the base 2 and parallel to the X-axis direction, and a motor driven X slidably provided on the pair of guide rails 15. It has an axis table 16. Further, the chuck table moving mechanism 4 is slidably disposed on the pair of guide rails 17 and the pair of guide rails 17 arranged on the upper surface of the X-axis table 16 and parallel to the Y-axis direction. It has the Y-axis table 18 of a motor drive.

The chuck table 3 is provided above the Y-axis table 18. Moreover, the nut part which is not shown in figure is formed in the back side of the X-axis table 16 and the Y-axis table 18, respectively, and the ball screw 21, 22 is screwed together by these nut parts. Then, the drive motors 23 and 24 connected to one ends of the ball screws 21 and 22 are driven to rotate, so that the chuck table 3 moves along the guide rails 15 and 17 in the X-axis direction and the Y-axis direction. do.

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

The laser processing unit 5 has a processing head 31 provided at the tip of the arm portion 12. In the arm part 12 and the processing head 31, the optical system of the laser processing unit 5 is provided. The processing head 31 collects a laser beam oscillated from an oscillator (not shown) by a condenser lens, and laser-processes the wafer W held on the chuck table 3. The laser light is a wavelength having absorbance with respect to the wafer W, and is adjusted to focus on the surface (processing surface) of the wafer W in an optical system.

In this case, the surface of the wafer W is covered with the protective film 85 formed by the protective film coating apparatus 6 (refer FIG. 2) mentioned later. The laser light from the processing head 31 is irradiated onto the surface of the wafer W through the protective film 85, whereby ablation occurs on the surface of the wafer W and is 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 adhere directly 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, thereby laser processing (ablation processing) along the division scheduled line of the wafer W. Here, ablation means that when the irradiation intensity of the laser beam is equal to or more than a predetermined processing threshold value, the solid surface is converted into electrons, thermal, optical, and mechanical energy, and as a result, neutral atoms, molecules, positive ions, Radicals, clusters, electrons, and light are exploded and the solid surface is etched.

With reference to FIG. 2, the protective film coating apparatus which coats a protective film on the surface of a wafer is demonstrated. 2 is a perspective view of the protective film coating device according to the present embodiment. In addition, the protective film coating apparatus which concerns on this embodiment is not limited to the spin coat type apparatus shown in FIG. Any structure may be sufficient as a protective film coating apparatus as long as it is a structure which supplies a liquid resin to the surface of a wafer, and forms a protective film.

As shown in FIG. 2, the protective film coating apparatus 6 supplies liquid resin R with respect to the wafer W on the holding table 41, and responds to the centrifugal force accompanying rotation of the holding table 41. As shown in FIG. It is comprised so that liquid resin R may be apply | coated to the whole surface of the wafer W by this. The protective film coating apparatus 6 has a cylindrical casing 37 having a bottom composed of a cylindrical circumferential wall portion 35 and a bottom wall portion 36. The casing 37 is supported on the mounting surface 39 by a plurality of leg portions 38 (three in this embodiment) extending from the bottom surface of the bottom wall portion 36. The holding table 41 is accommodated in the casing 37, and the liquid resin nozzle 42, the washing water nozzle 43, and the air nozzle 44 are provided around the holding table 41.

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

On the outer circumferential surface of the electric motor 45, a plurality of air cylinders 48 (in this embodiment, three) are attached. The electric motor 45 is supported by the piston rod 47 in contact with 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 high speed in the casing 37 by the electric motor 45, and the lowering position at which the wafer W is picked up by the plurality of air cylinders 48 and the processing are performed. Drive up and down between positions.

The liquid resin nozzle 42 is formed in a substantially L shape with a horizontal portion 51 extending horizontally from above the holding table 41 and a vertical portion 52 extending downward from the base end of the horizontal portion 51. It is. The tip portion of the horizontal portion 51 is bent downward, and the liquid resin R is dripped onto the wafer W on the holding table 41 from the curved tip portion. In addition, the liquid resin nozzle 42 is supported by the casing 37 so as to be rotatable from above the holding table 41. Liquid resin R is supplied to this liquid resin nozzle 42 from the liquid resin supply part 8 (liquid resin supply means) mentioned later.

In the protective film coating apparatus 6, when liquid resin R is dripped from the liquid resin nozzle 42 to the surface center of the wafer W, the holding table 41 will rotate at high speed, and centrifugal force will act on liquid resin R by this. do. By this centrifugal force, the liquid resin R spreads over the entire surface of the wafer W to form a protective film 85 (see FIG. 4C). The wafer W on which the protective film 85 is formed is rearranged on the chuck table 3 and subjected to laser processing. At the time of laser processing, since the surface of the wafer W is covered with the protective film 85 as mentioned above, debris does not adhere directly to the surface of the wafer W. As shown in FIG.

Moreover, as liquid resin R, water-soluble resin, such as polyvinyl alcohol (PVA) and polyethylene glycol (PEG), is dripped at the wafer W, for example. Moreover, it is preferable to add the absorber which absorbs the light of a laser wavelength to liquid resin (R). As a result, the protective film 85 is also removed simultaneously with the processing of the wafer W at the time of laser processing, so that the protective film 85 is peeled off from the surface of the wafer W by steam or the like of thermal decomposition products of the wafer W. Is prevented.

In addition, the protective film coating device 6 not only forms the protective film 85 on the wafer W before processing, but also functions as a cleaning device for removing the protective film 85 from the processed wafer W. FIG. In the casing 37, like the liquid resin nozzle 42, the washing water nozzle 43 and the air nozzle 44 are rotatably provided. The washing water nozzle 43 and the air nozzle 44 respectively extend horizontally above the holding table 41 and extend downward from the base ends of the horizontal parts 53 and 55. The vertical part 54 (the vertical part of the air nozzle 44 is not shown) is formed in substantially L shape. The front end portions of the washing water nozzle 43 and the air nozzle 44 are bent downward, respectively, and the washing water and the drying air are sprayed onto the wafer W from the bent end portions.

During the cleaning of the protective film coating device 6, the processed wafer W is held on the holding table 41, and the holding table 41 is rotated at a high speed while spraying the washing water from the washing water nozzle 43. By spraying washing water on the surface of the wafer W, the protective film 85 with debris adheres from the processed wafer W. The waste liquid at the time of washing | cleaning is discharged | emitted through the drain hose 58 connected to the casing 37. FIG. Thereafter, the dry air is sprayed from the air nozzle 44 onto the rotating wafer W to dry the wafer W. As shown in FIG.

With reference to FIG. 3, the flow path structure and control structure of a liquid resin supply part are demonstrated. 3 is a schematic diagram of a piping configuration and a control configuration of the liquid resin supply unit according to the present embodiment. In addition, the liquid resin supply part which concerns on this embodiment is not limited to the structure shown in FIG. The liquid resin supply part may be any structure as long as the liquid resin sent out from the accommodation tank to the liquid resin nozzle is temporarily stored in a storage container functioning as a buffer tank.

As shown in FIG. 3, the liquid resin supply part 8 contains the accommodating tank 61 which accommodates liquid resin R as a main tank, and the liquid resin R as a buffer tank downstream of the accommodating tank 61. As shown in FIG. The storage container 62 which stores is stored. The storage tank 61 is connected to the storage container 62 via the first pipe 63, and the storage container 62 is connected to the liquid resin nozzle 42 through the second pipe 64. In the middle part of the 1st piping 63, the 1st delivery pump 65 which delivers the liquid resin R from the accommodation tank 61 to the storage container 62 is provided. In the middle part of the 2nd piping 64, the 2nd delivery pump 66 which delivers the liquid resin R from the storage container 62 to the liquid resin nozzle 42 is provided. In addition, the liquid resin supply part 8 is collectively controlled by the control part 9.

The storage tank 61 is formed in the box shape, and the 1st sending pipe 67 which delivers the liquid resin R in a tank is provided. One end of the first delivery pipe 67 is located near the bottom surface 68 of the accommodation tank 61, and the other end thereof is connected to the first pipe 63. In addition, the accommodating tank 61 is provided with the air communication part which is not shown in figure which makes the tank communicate with the atmosphere. In the storage tank 61, the storage tank residual amount sensor 69 is provided in the position slightly higher than the one end (lower end) of the 1st sending pipe 67. As shown in FIG. The storage tank residual amount sensor 69 is connected to the control part 9, detects that the liquid resin R in a tank is below the predetermined quantity, and notifies the control part 9 of it.

The storage container 62 is formed in the box shape which opened the upper surface to the air | atmosphere, The introduction pipe 71 which introduces liquid resin R in a container, and the 2nd sending which sends liquid resin R in a container are sent out. The pipe 72 is provided. In addition, the second discharge pipe 72 functions as a discharge port 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 paper sheet, and the other end is connected to the first pipe 63. One end of the second delivery pipe 72 is located near the bottom surface 75 of the storage container 62 on the side surface 74 side of the left side of the paper, and the other end thereof is connected to the second pipe 64. In addition, a first detection sensor 76 is provided above the storage container 62. Below the storage container 62, the second detection sensor 77 is provided at a position slightly higher than one end (lower end) of the second delivery pipe 72.

The 1st detection sensor 76 is connected to the control part 9, detects the upper limit liquid level position P1 of liquid resin R in a container, and notifies the control part 9 to it. The 2nd detection sensor 77 is connected to the control part 9, detects the lower limit liquid level position P2 of the liquid resin R in a container, and notifies the control part 9 to it. In the storage container 62, a plurality of (3 in this embodiment) bubble removing filters 78 formed in a flat shape are disposed over the front surface side, the ground inner side, and the bottom surface 75 of the storage container 62. It is. The some bubble removal filter 78 is arrange | positioned in parallel with the standing posture raised up in the substantially perpendicular direction with respect to the flow direction of the liquid resin which flows toward the side surface 74 from the side surface 73 of the storage container 62. .

Each bubble removing filter 78 has a mesh-type bubble trapping portion 79 for trapping bubbles in the liquid resin R. As shown in FIG. In the storage container 62, when the liquid resin flows from the side surface 73 to the side surface 74, the liquid resin R passes through the bubble trapping portion 79 to remove bubbles in the liquid resin R. 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 form, and may be formed in pleat form. In addition, the bubble capture | acquisition part 79 sets the size and number of meshes according to the density | concentration of liquid resin R, a delivery speed, and a delivery amount. For example, when the delivery amount is large, the mesh is set large.

In addition, in this embodiment, although each bubble removal filter 78 was provided in the substantially perpendicular direction with respect to the flow direction of liquid resin R, a substantially vertical direction is not limited to a perfect vertical direction, but according to the error of adhesion accuracy It means having a width. That is, the substantially perpendicular direction with respect to the flow direction of the liquid resin R includes the extent which can be seen as substantially perpendicular to the flow direction of the liquid resin R. As shown in FIG. In addition, one bubble trapping unit 79 may be provided in one bubble removing filter 78, or a plurality of bubble trapping units 79 may be provided depending on the concentration of the liquid resin R or the like.

The 1st, 2nd delivery pump 65 and 66 are respectively connected to the control part 9, and are driven by the control of the control part 9. As shown in FIG. When the 1st sending pump 65 is driven by the control part 9, the liquid resin R is pumped up from the vicinity of the bottom surface 68 of the accommodation tank 61 by the 1st sending pipe 67, The liquid resin R is sent out toward the storage container 62 via the one pipe 63. When the second delivery pump 66 is driven by the control unit 9, the liquid resin R is pumped up from the vicinity of the bottom surface 75 of the storage container 62 by the second delivery pipe 72. The liquid resin R is sent out to the liquid resin nozzle 42 via the two pipes 64.

The control part 9 controls the drive timing of the 1st, 2nd delivery pump 65, 66, and monitors the residual amount of the liquid resin R in the storage tank 61. As shown in FIG. Moreover, the control part 9 is connected with the notification part 81 (notification means) for promoting replenishment of the liquid resin R in the storage tank 61. Moreover, the control part 9 is comprised by the processor which performs various processes, a memory, etc. The memory is composed of one or a plurality of storage media, such as a read only memory (ROM) and a random access memory (RAM), depending on the purpose. The memory also stores a control program for controlling the operations of the first and second delivery pumps 65 and 66, the notification unit 81 and the like.

The control part 9 drives the 1st delivery pump 65 according to the detection signal input from the 1st detection sensor 76, and according to the detection signal input from the 2nd detection sensor 77, the 1st delivery pump ( 65) Stop. Therefore, when the liquid level of the liquid resin R in the storage container 62 goes down to the lower limit liquid level position P2, the liquid surface position of the liquid level of the liquid resin R in the storage container 62 is higher than the liquid level in the storage container 62 ( The liquid resin R is replenished until it becomes P1). In this way, the liquid resin R more than a predetermined amount is secured in the storage container 62. In addition, since the lower limit liquid level position P2 is at a position 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 flow rate, so that the second delivery pipe 72 is located. Air does not enter inside

The control part 9 drives control of the 2nd delivery pump 66 so that liquid resin R may be sent according to the application amount of liquid resin R dripped from the liquid resin nozzle 42 to the wafer W. As shown in FIG. By the drive of the second delivery pump 66, a flow of the liquid resin R from the side surface 73 to the side surface 74 occurs in the storage container 62, and the liquid resin R is formed of a plurality of bubble removing filters. By passing through the 78, bubbles in the liquid flow are captured by the bubble capturing unit 79. For this reason, the liquid resin R from which the bubble was removed is sucked into the 2nd delivery pipe 72. Therefore, the downstream side of the storage container 62, that is, inside the second delivery pipe 72, inside the second pipe 64, and inside the liquid resin nozzle 42 is always filled with the liquid resin R from which bubbles are removed. .

The control unit 9 informs the notification unit 81 that the remaining amount of the liquid resin R in the storage tank 61 is less than a predetermined amount in accordance with a detection signal input from the storage tank remaining amount sensor 69. The notification unit 81 also notifies by at least one of a voice notification, a light emission notification, and a display notification. By the notification of the notification part 81, the replacement operation of the accommodation tank 61 and the replenishment operation of liquid resin are accelerated | stimulated to an operator. At this time, since the storage container 62 functions as a buffer tank of the storage tank 61, the productivity can be improved without stopping the protective film coating device 6 even during the replacement operation of the storage tank 61. .

Next, with reference to FIG. 4, the flow of protective film formation by a protective film coating apparatus is demonstrated. 4 is an explanatory diagram of a protective film formation flow by the protective film coating device according to the present embodiment. In addition, in FIG. 4, the protective film coating apparatus is simplified and described for convenience of description.

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 pivots, and the tip portion of the nozzle is positioned at the center of the wafer W. As shown in FIG. Next, as shown in FIG. 4B, the second delivery pump 66 is driven by the control unit 9, and the liquid resin R is added dropwise to the wafer W from the liquid resin nozzle 42. The liquid pool R1 is formed in the center of the surface of the wafer W. As shown in FIG.

At this time, the liquid resin R in the storage container 62 is supplied to the liquid resin nozzle 42 via the plurality of bubble removing filters 78. Since the inside of the liquid resin nozzle 42 and the inside of the second pipe 64 are filled with the liquid resin R from which the bubbles have been removed, the liquid resin R into which the bubbles are mixed is transferred from the liquid resin nozzle 42 to the wafer W. ) Is not loaded onto. When the predetermined amount of liquid resin R is dripped from the liquid resin nozzle 42 with respect to the wafer W, the 2nd delivery pump 66 is stopped by the control part 9. Then, the liquid resin nozzle 42 is turned, and the tip portion of the nozzle is released from the upper side of the wafer W. As shown in FIG.

Next, as shown in FIG. 4C, the holding table 41 holding the wafer W rotates at high speed. Thereby, centrifugal force acts on the liquid pool R1 of the liquid resin R in the center of the upper surface of the wafer W, and the liquid resin R spreads so that the whole upper surface of the wafer W may be covered. By solidifying this liquid resin R, the protective film 85 is formed in the upper surface of the wafer W. As shown in FIG. Since the bubbles in the liquid resin R are removed, no holes are formed due to the bubbles remaining in the protective film 85, and a good protective film 85 is formed on the upper surface of the wafer W. As shown in FIG.

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. And the wafer W is rearranged from the holding table 41 to the chuck table 3 (refer FIG. 1), and laser processing of a back end is performed. The laser processing completed wafer W is carried in to the protective film coating apparatus 6 again, and the protective film 85 with the debris is washed.

As mentioned above, according to the laser processing apparatus 1 which concerns on this embodiment, liquid resin R is replenished from the storage tank 61 to the storage container 62, and the storage container 62 is made to function as a buffer tank. Can be. Therefore, even when the remaining amount of the liquid resin R in the storage tank 61 decreases and the replacement operation of the storage tank 61 occurs, the protective film coating device 6 is not stopped, but the inside of the storage container 62 is kept. The protective film 85 can be formed in the wafer W by the liquid resin R. As shown in FIG. Moreover, the liquid resin R in which the bubble was removed from the storage container 62 to the liquid resin nozzle 42 is sent out by the bubble removal filter 78 installed in the storage container 62. For this reason, since the inside of the 2nd piping 64 which connects the storage container 62 and the liquid resin nozzle 42 is filled with the liquid resin R in which the bubble was removed, the liquid resin R in which the bubble was mixed becomes liquid It is not dripped from the resin nozzle 42 with respect to the wafer W. As shown in FIG. Therefore, bubbles do not remain in the protective film 85, and the surface of the wafer W can be covered with a good protective film 85.

Further, the present invention is not limited to the above-described embodiment, and various modifications can be made. In the above embodiment, the size, shape, and the like shown in the accompanying drawings are not limited to this, and can be appropriately changed within the range in which the effects of the present invention are exhibited. In addition, it is possible to change suitably and to implement, unless it deviates from the desired range of this invention.

For example, in the above embodiment, the first and second detection sensors 76 and 77 are installed in the storage container 62, and from the holding tank 61 in accordance with the detection of the first and second detection sensors 76 and 77. Although the storage container 62 was made into the structure which replenishes liquid resin R, it is not limited to this structure. When the liquid resin R is replenished periodically from the storage tank 61 to the storage container 62, the first and second detection sensors 76 and 77 are not provided in the storage container 62. Also good. In addition, the replenishment timing of the liquid resin R from the storage tank 61 to the storage container 62 can be appropriately changed.

In addition, in the said embodiment, although the liquid resin supply part 8 set it as the structure which has each the storage tank 61 and the storage container 62, it is not limited to this structure. The liquid resin supply part 8 may be configured to have a plurality of storage tanks 61 and a plurality of storage containers 62.

In addition, in the said embodiment, although it was set as the structure which installs the introduction pipe 71 in the side surface 73 of the storage container 62, and installs the 2nd delivery pipe 72 in the side surface 74, it is limited to this structure. It doesn't work. When the introduction pipe 71 and the second delivery pipe 72 are provided such that the liquid resin R introduced from the introduction pipe 71 is sent out from the second delivery pipe 72 through the bubble removing filter 78. It may be installed in any position.

Moreover, in the said embodiment, in the storage container 62, the partition wall which formed the clearance gap is provided between the bubble removal filter 78 and the introduction pipe 71 so that a big bubble can be removed from liquid resin R. You may comprise. In this case, it is only necessary to be able to remove large bubbles on the upstream side of the bubble removing filter 78, and for example, large bubbles may be removed by a filter having a sparse eye.

As described above, the present invention has the effect that a good protective film can be formed on a wafer without lowering the productivity, and is particularly useful for a laser processing apparatus that performs ablation along a division scheduled line.

DESCRIPTION OF SYMBOLS 1: Laser processing apparatus, 3: Chuck table, 5: Laser processing unit (laser light irradiation means), 6: Protective film coating apparatus, 8: Liquid resin supply part (liquid resin supply part), 9: Control part, 41: Holding table, 42 : Liquid resin nozzle, 61: Storage tank, 62: Storage container, 63: 1st piping, 64: 2nd piping (piping), 65: 1st sending pump, 66: 2nd sending pump, 69: Retaining tank residual amount sensor 76: 1st detection sensor, 77: 2nd detection sensor, 78: bubble removal filter, 79: bubble capture | acquisition part, 81: notification part, 85: protective film, W: wafer, R: liquid resin, P1: upper limit liquid level position , P2: lower limit face position

Claims (2)

A laser processing apparatus comprising at least a chuck table for holding a wafer, laser light irradiation means for irradiating a laser beam to a wafer held on the chuck table, and a protective film coating device for covering the processed surface of the wafer with a protective film,
The protective film coating device includes a holding table holding a wafer, a liquid resin nozzle dropping liquid resin onto a processing surface of the wafer held on the holding table, and a liquid resin supply means communicating with the liquid resin nozzle,
The liquid resin supply means includes at least one storage tank for storing liquid resin, a storage container for storing the liquid resin contained in the storage tank, and a first delivery pump for sending the liquid resin from the storage tank to the storage container. And a second delivery pump for sending liquid resin from the storage container to the liquid resin nozzle, and a control unit for controlling the first delivery pump and the second delivery pump,
In the storage container, a bubble is disposed over the side and bottom surface of the storage container in a direction substantially perpendicular to the flow direction of the liquid resin and formed in a flat shape, and having a mesh-shaped bubble trapping portion for capturing bubbles in the liquid resin. The removal filter is installed,
The inside of the piping which connects the outlet of the said storage container and the said liquid resin nozzle is filled with the liquid resin from which the bubble was removed, The laser processing apparatus characterized by the above-mentioned. The storage tank remaining amount sensor according to claim 1, further comprising a storage tank remaining amount sensor for detecting that the liquid resin contained in the storage tank is less than a predetermined amount.
And the control unit notifies the notifying means that the predetermined amount falls below a predetermined amount when a detection signal from the storage tank remaining amount sensor is input.

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