JP7450426B2 - Processing method of workpiece - Google Patents

Description

The present invention relates to a method for processing a workpiece.

Device wafers on which devices are formed using insulating films with a low dielectric constant (low-k films) are manufactured. Since the low-k film has low mechanical strength, it will peel off from the wafer when it is diced with a cutting blade that is normally used for dividing wafers. For this reason, a technique is known in which the low-k film is divided by laser ablation processing and then the wafer is divided by a cutting blade. In laser ablation processing, in order to prevent the generated debris from adhering to the device, a protective film made of water-soluble resin is coated before laser processing, and after the processing is completed, the protective film is removed along with the debris by washing with water. is used (see Patent Document 1).

Patent No. 451850

Regarding the above processing method, a problem was discovered in that the protective film gradually deteriorates due to high-temperature debris, so if it is not cleaned immediately after laser processing, it becomes difficult to remove the debris even if it is covered with a protective film. There is no problem if the protective film is cleaned immediately after laser processing, but if dicing cannot be performed immediately, the wafer is sometimes stored with the protective film coated to protect the wafer surface. In this case, the protective film may be altered by the high-temperature debris, making it difficult to remove the debris before dicing.

The present invention has been made in view of these problems, and its purpose is to easily remove debris caused by laser processing even when the workpiece is temporarily stored with a protective film coated on the surface of the workpiece after laser processing. It is an object of the present invention to provide a method for processing a workpiece.

In order to solve the above-mentioned problems and achieve the objects, the method of processing a workpiece according to the present invention provides a method for processing a workpiece in which a device is formed in a region defined by a dividing line on the surface of the workpiece. The processing method includes a first coating step of coating the surface of the workpiece with a water-soluble protective film, and after performing the first coating step, a laser beam having an absorbing wavelength is applied to the workpiece. A laser processing step of irradiating from the surface of the workpiece along the planned dividing line to form a laser processing groove along the planned dividing line on the surface of the workpiece, and after performing the laser processing step, After performing the protective film cleaning step of cleaning the surface of the workpiece and removing debris generated in the laser processing step together with the water-soluble protective film, the surface of the workpiece and the water-soluble protective film are cleaned again. After sequentially carrying out the second coating step of coating the water-soluble protective film on the laser-processed groove , the first coating step, the laser processing step, the protective film cleaning step, and the second coating step, the water-soluble a cutting step of removing the water-soluble protective film with the water while supplying water to the surface of the workpiece coated with the water-soluble protective film and forming a dividing groove with a cutting blade in the center of the laser-processed groove; It is characterized by comprising the following.

Using a laser processing device that includes a laser processing unit that processes a workpiece, a protective film coating unit that coats the workpiece with the water-soluble protective film, and a cleaning unit that washes the workpiece with water, After successively performing the first coating step, the laser processing step, the protective film cleaning step, and the second coating step, the workpiece is taken out from the laser processing device and water is supplied to the workpiece. While supplying water to the surface of the workpiece coated with the water-soluble protective film using a cutting device that cuts with a cutting blade, while forming a dividing groove with the cutting blade in the center of the laser processing groove, The cutting step may be performed to remove the water-soluble protective film with the water. Moreover, after implementing the cutting step, an additional cleaning step may be provided in which water is supplied to the workpiece by a cleaning unit included in the cutting apparatus to clean the surface of the workpiece.

Further, after the second coating step and before the cutting step, the workpiece whose surface and the laser-processed grooves are coated with the water-soluble protective film may be stored for a predetermined period of time or longer.

The present invention can facilitate the removal of debris by laser processing even when the workpiece is temporarily stored with a protective film coated on the surface of the workpiece after laser processing.

FIG. 1 is a perspective view showing an example of a workpiece according to an embodiment. FIG. 2 is a flowchart showing the flow of the method for processing a workpiece according to the embodiment. FIG. 3 is a side view, partially in cross section, of an example of the first coating step shown in FIG. FIG. 4 is a sectional view of a main part of the workpiece showing a state after the first coating step of FIG. 3. FIG. FIG. 5 is a side view, partially in cross section, of an example of the laser processing step shown in FIG. FIG. 6 is a cross-sectional view of a main part of the workpiece showing one state after the laser processing step of FIG. 5. FIG. FIG. 7 is a side view, partially in section, showing an example of the protective film cleaning step shown in FIG. FIG. 8 is a sectional view of a main part of the workpiece showing a state after the protective film cleaning step of FIG. 7. FIG. FIG. 9 is a side view, partially in section, of an example of the second coating step shown in FIG. FIG. 10 is a sectional view of a main part of the workpiece showing a state after the second coating step of FIG. 9. FIG. FIG. 11 is a flowchart showing the flow of a method for processing a workpiece according to a modification. FIG. 12 is a perspective view showing a configuration example of a laser processing apparatus that performs the first coating step, laser processing step, protective film cleaning step, and second coating step shown in FIG. 11. FIG. 13 is a perspective view showing a configuration example of a cutting device that performs the cutting step and additional cleaning step shown in FIG. 11. FIG. 14 is a side view, partially in cross section, of an example of the cutting step shown in FIG. 11. FIG. 15 is a sectional view of a main part of the workpiece showing one state after the cutting step of FIG. 14. FIG. FIG. 16 is a side view, partially in cross section, of an example of the additional cleaning step shown in FIG. 11. FIG. 17 is a sectional view of a main part of the workpiece showing a state after the additional cleaning step of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Further, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[Embodiment]
A method for processing a workpiece 10 according to an embodiment of the present invention will be described based on the drawings. First, the configuration of the workpiece 10 that is the processing target of the embodiment will be described. FIG. 1 is a perspective view showing an example of a workpiece 10 according to an embodiment.

As shown in FIG. 1, the workpiece 10 is a disk-shaped semiconductor wafer whose substrate 11 is silicon (Si), sapphire (Al ₂ O ₃ ), gallium arsenide (GaAs), silicon carbide (SiC), or the like; These are wafers such as optical device wafers. The workpiece 10 has a plurality of dividing lines 13 formed on the surface 12 of the substrate 11, and a device 14 formed in each region defined by the plural dividing lines 13 intersecting in a grid pattern.

The device 14 is, for example, an integrated circuit such as an IC (Integrated Circuit) or LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device), or a CMOS (Complementary Metal Oxide Semiconductor), or an MEMS (Micro Electrode Semiconductor). Mechanical Systems) etc.

Further, in the workpiece 10, a functional layer 16 is laminated on the surface 12 of the substrate 11. The functional layer 16 is a low dielectric constant insulating film (hereinafter referred to as a low-k film) made of an organic film such as an inorganic film such as SiOF or BSG (SiOB) or a polymer film such as polyimide or parylene. ) and a conductive film made of a conductive metal. The low-k film is laminated with a conductive film to form the device 14. The conductor film constitutes the circuit of the device 14. For this purpose, the device 14 is composed of low-k films stacked on each other and conductor films stacked between the low-k films. Note that the functional layer 16 on the planned dividing line 13 is composed of a low-k film, and does not include a conductive film except for a TEG (Test Element Group). The TEG is an evaluation element for finding design and manufacturing problems that occur in the device 14.

The workpiece 10 is supported by an annular frame 30 and an adhesive tape 31. The annular frame 30 has an opening larger than the outer diameter of the workpiece 10. The annular frame 30 is made of a material such as metal or resin that is resistant to plasma etching. The adhesive tape 31 includes a base layer made of an insulating synthetic resin, and an adhesive layer laminated on at least one of the front and back sides of the base layer. The outer periphery of the adhesive tape 31 is attached to the back side of the annular frame 30. The workpiece 10 is positioned at a predetermined position in the opening of the annular frame 30 and is fixed to the annular frame 30 and the adhesive tape 31 by adhering the back surface 15 to the adhesive tape 31 .

Next, a method for processing the workpiece 10 according to the embodiment will be described. FIG. 2 is a flowchart showing the flow of the method for processing the workpiece 10 according to the embodiment. The method for processing the workpiece 10 includes a first coating step 1, a laser processing step 2, a protective film cleaning step 3, and a second coating step 4.

(First coating step 1)
FIG. 3 is a side view, partially in cross section, of an example of the first coating step 1 shown in FIG. FIG. 4 is a sectional view of a main part of the workpiece 10 showing one state after the first coating step 1 of FIG. 3. FIG. As shown in FIGS. 3 and 4, the first coating step 1 is a step of coating the surface 12 of the workpiece 10 with a water-soluble protective film 20.

In the first coating step 1 of the embodiment, the surface 12 of the workpiece 10 is coated with a water-soluble resin 55 by the protective film coating unit 50 . The protective film coating unit 50 includes a spin coater in an embodiment. The protective film coating unit 50 includes a holding table 51, a clamp member 52, a rotating shaft member 53, and a water-soluble resin supply nozzle 54.

In the first covering step 1, first, the back surface 15 side of the workpiece 10 is suctioned and held on the holding table 51 via the adhesive tape 31, and the outer periphery of the annular frame 30 is fixed with the clamp member 52. In the first coating step 1, the water-soluble resin 55 is dripped onto the surface 12 of the workpiece 10 from the water-soluble resin supply nozzle 54 while the holding table 51 is rotated around the axis by the rotating shaft member 53. let At this time, the water-soluble resin supply nozzle 54 may reciprocate in the radial direction of the workpiece 10. The dropped water-soluble resin 55 flows on the surface 12 of the workpiece 10 from the center toward the outer circumference due to the centrifugal force generated by the rotation of the holding table 51, and the water-soluble resin 55 flows on the surface 12 of the workpiece 10 from the center to the outer circumference. It is applied all over.

The water-soluble resin 55 is, for example, a water-soluble liquid resin such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP). As the water-soluble resin 55, for example, HOGOMAX (registered trademark) manufactured by DISCO Co., Ltd. is used. In the first coating step 1, a layer of water-soluble resin 55 covering the entire surface 12 of the workpiece 10 is formed by drying and curing the water-soluble resin 55 applied to the entire surface 12 of the workpiece 10. Form. As a result, the surface 12 of the workpiece 10 is covered with the water-soluble protective film 20 formed by the layer of the water-soluble resin 55. Water-soluble protective film 20 is transparent in embodiments. As a result, a camera (for example, the imaging unit 140 or the image pickup unit 140 in FIG. 11) of a laser processing unit 60, a laser processing device (for example, the laser processing device 100 in FIG. 12), or a cutting device (for example, the cutting device 200 in FIG. 13), which will be described later, Alignment using 13 imaging units 260) is possible.

(Laser processing step 2)
FIG. 5 is a side view, partially in cross section, of an example of the laser processing step 2 shown in FIG. FIG. 6 is a sectional view of a main part of the workpiece 10 showing one state after the laser processing step 2 in FIG. 5. FIG. Laser processing step 2 is performed after performing first coating step 1. As shown in FIGS. 5 and 6, the laser processing step 2 irradiates the workpiece 10 with a laser beam 65 having an absorbing wavelength from the surface 12 of the workpiece 10 along the dividing line 13, This is a step of forming laser-processed grooves 21 along the planned dividing line 13 on the surface 12 of the workpiece 10 .

In the laser processing step 2 of the embodiment, the laser processing unit 60 forms the laser processing grooves 21 along the dividing lines 13 formed on the surface 12 of the workpiece 10 . The laser processing unit 60 includes a holding table 61, a clamp member 62, a rotating shaft member 63 of the holding table 61, a laser beam irradiation unit 64, and a movement unit that relatively moves the holding table 61 and the laser beam irradiation unit 64. , is provided.

In the laser processing step 2, first, the back surface 15 side of the workpiece 10 is suction-held on the holding table 61 via the adhesive tape 31, and the outer circumference of the annular frame 30 is fixed with the clamp member 62. In laser processing step 2, next, while relatively moving the holding table 61 and the laser beam irradiation unit 64 along the dividing line 13, the laser beam 65 is applied from the laser beam irradiation unit 64 to divide the surface 12 of the workpiece 10. The planned line 13 is irradiated. The laser beam 65 has a wavelength that is absorbent to the workpiece 10 .

As shown in FIG. 6, the laser beam 65 removes the water-soluble protective film 20 covering the entire surface 12 of the workpiece 10 in a region corresponding to the dividing line 13, thereby forming the laser-processed groove. 21 is formed. As shown in FIG. 6, the laser processing groove 21 removes a portion of the water-soluble protective film 20, the functional layer 16, and a portion of the substrate 11 in a region corresponding to the planned dividing line 13 to expose the substrate 11. Thereby, the water-soluble protective film 20 covers the device 14 and exposes the planned dividing line 13 on the surface 12 of the workpiece 10 . At this time, debris 22 generated by laser processing adheres to the surface of the water-soluble protective film 20.

(Protective film cleaning step 3)
FIG. 7 is a side view, partially in cross section, of an example of the protective film cleaning step 3 shown in FIG. FIG. 8 is a sectional view of a main part of the workpiece 10 showing one state after the protective film cleaning step 3 of FIG. 7. The protective film cleaning step 3 is performed after the laser processing step 2 is performed. As shown in FIGS. 7 and 8, the protective film cleaning step 3 is a step in which the surface 12 of the workpiece 10 is cleaned and the debris 22 generated in the laser processing step 2 is removed together with the water-soluble protective film 20.

In the protective film cleaning step 3 of the embodiment, the cleaning unit 70 removes the water-soluble protective film 20 covering the surface 12 of the workpiece 10 by cleaning it with water 75 . The cleaning unit 70 includes a holding table 71, a clamp member 72, a rotating shaft member 73, and a cleaning nozzle 74.

In the protective film cleaning step 3, first, the back surface 15 side of the workpiece 10 is suctioned and held on the holding table 71 via the adhesive tape 31, and the outer periphery of the annular frame 30 is fixed with the clamp member 72. In the protective film cleaning step 3, water 75 is then supplied from the cleaning nozzle 74 toward the surface 12 of the workpiece 10 while the holding table 71 is rotated around the axis by the rotating shaft member 73. The water 75 is pressurized water whose pressure is adjusted to about 10 to 12 MPa in a waterway upstream of the cleaning nozzle 74. The water 75 is, for example, pure water. The water 75 may be bubble water mixed with air. Alternatively, cleaning may be performed using a so-called two-fluid mixture of water and air.

The cleaning nozzle 74 reciprocates in the radial direction of the workpiece 10 while supplying water 75. The supplied water 75 flows over the surface 12 of each device 14 of the workpiece 10 from the center toward the outer periphery due to the centrifugal force generated by the rotation of the holding table 71. The water-soluble protective film 20 covering the wafer is washed. By cleaning the water-soluble protective film 20 covering the surface 12 of each device 14 of the workpiece 10, the surface 12 of the device 14 is exposed.

The cleaning unit 70 may also serve as the protective film coating unit 50. More specifically, the holding table 71, the clamp member 72, and the rotating shaft member 73 of the cleaning unit 70 may also be used as the holding table 51, the clamp member 52, and the rotating shaft member 53 of the protective film coating unit 50.

In an embodiment, the protective film cleaning step 3 is performed immediately after the laser processing step 2 is performed. Note that "immediately after" refers to after the laser processing step 2 and after the time required for the workpiece 10 on which the laser processing step 2 was performed by the laser processing unit 60 to be transported to the cleaning unit 70 has elapsed. By performing the protective film cleaning step 3 immediately after performing the laser processing step 2, the water-soluble protective film 20 can be dissolved before it gradually changes in quality due to the high temperature debris 22 and becomes difficult to remove.

(Second coating step 4)
FIG. 9 is a side view, partially in cross section, of an example of the second coating step 4 shown in FIG. FIG. 10 is a sectional view of a main part of the workpiece 10 showing one state after the second coating step 4 of FIG. 9. As shown in FIG. The second coating step 4 is performed after the protective film cleaning step 3 is performed. As shown in FIGS. 9 and 10, the second coating step 4 is a step of coating the surface 12 of the workpiece 10 with the water-soluble protective film 20 again.

In the second coating step 4 of the embodiment, the surface 12 of the workpiece 10 and the laser processing groove 21 are coated with the water-soluble resin 55 by the protective film coating unit 50 used in the first coating step 1. The procedure for applying the water-soluble resin 55 by the protective film coating unit 50 is the same as the first coating step 1, and therefore the description thereof will be omitted. By applying the water-soluble resin 55 again to the workpiece 10 on which the laser processing grooves 21 have been formed, the surface 12 of the workpiece 10 and the side surfaces of the functional layer 16 and the substrate 11 exposed by the laser processing grooves 21 are also removed. The water-soluble protective film 20 is coated with a layer of water-soluble resin 55 .

In an embodiment, the second coating step 4 is carried out immediately after carrying out the overcoat cleaning step 3. Immediately after is after the protective film cleaning step 3 and after the time required for the workpiece 10 on which the protective film cleaning step 3 has been carried out by the cleaning unit 70 to be transported to the protective film coating unit 50 has elapsed. means. By performing the second coating step 4 immediately after performing the protective film cleaning step 3, it is possible to prevent foreign matter from adhering to the workpiece 10 and covering the foreign matter together with the water-soluble protective film 20.

[Modified example]
A method for processing a workpiece 10 according to a modification of the present invention will be described based on the drawings. FIG. 11 is a flowchart showing the flow of a method for processing a workpiece 10 according to a modification. The method of processing the workpiece 10 in the modified example includes a first coating step 1, a laser processing step 2, a protective film cleaning step 3, a second coating step 4, a cutting step 5, an additional cleaning step 6, including. In a modification, the first coating step 1, the laser processing step 2, the protective film cleaning step 3, and the second coating step 4 are performed successively using the laser processing apparatus 100. Further, in a modified example, the cutting step 5 and the additional cleaning step 6 are performed using the cutting device 200.

(Laser processing equipment configuration)
The configuration of the laser processing apparatus 100 that performs the first coating step 1, the laser processing step 2, the protective film cleaning step 3, and the second coating step 4 will be described. FIG. 12 is a perspective view showing a configuration example of a laser processing apparatus 100 that performs the first coating step 1, the laser processing step 2, the protective film cleaning step 3, and the second coating step 4 shown in FIG. In the following description, the X-axis direction is one direction on the horizontal plane. The Y-axis direction is a direction perpendicular to the X-axis direction in the horizontal plane. The Z-axis direction is a direction perpendicular to the X-axis direction and the Y-axis direction. In the laser processing apparatus 100 of the modified example, the processing feed direction is the X-axis direction, the indexing feed direction is the Y-axis direction, and the focusing point position adjustment direction is the Z-axis direction.

The laser processing apparatus 100 includes a laser processing unit 110, an X-axis movement unit 120, a Y-axis movement unit 130, an imaging unit 140, a protective film coating and cleaning unit 150, a mounting table 170, and a transport unit 180. and a control unit 190.

The laser processing unit 110 corresponds to the laser processing unit 60 of the embodiment, and is a unit that processes the workpiece 10 with a laser. The laser processing unit 110 includes a holding table 111 and a laser beam irradiation unit 114.

The holding table 111 holds the workpiece 10 with a holding surface 112 . A plurality of clamp members 113 are arranged around the holding table 111 to clamp the annular frame 30 that supports the workpiece 10 . The holding table 111 is rotated around an axis parallel to the Z-axis. The holding table 111 is moved in the X-axis direction by an X-axis movement unit 120 via an X-axis movement plate 121. The holding table 111 is moved in the Y-axis direction by the Y-axis movement unit 130 via the Y-axis movement plate 131. The laser beam irradiation unit 114 is a unit that irradiates the workpiece 10 held on the holding table 111 with a laser beam.

The X-axis direction movement unit 120 is a unit that relatively moves the holding table 111 and the laser beam irradiation unit 114 in the X-axis direction, which is the processing feed direction. The Y-axis direction movement unit 130 is a unit that relatively moves the holding table 111 and the laser beam irradiation unit 114 in the Y-axis direction, which is the indexing and feeding direction. The laser processing apparatus 100 may further include a Z-axis movement unit that relatively moves the holding table 111 and the laser beam irradiation unit 114 in the Z-axis direction in order to adjust the focal position of the laser beam irradiation unit 114.

The laser processing apparatus 100 performs laser processing on the workpiece 10 by irradiating the workpiece 10 with a laser beam from the laser beam irradiation unit 114 while relatively moving the holding table 111 and the laser beam irradiation unit 114. . Laser processing by the laser processing apparatus 100 includes, for example, modified layer forming processing in which a modified layer is formed inside the workpiece 10 by stealth dicing, and groove processing in which laser processing grooves 21 are formed on the surface 12 of the workpiece 10. , or a cutting process in which the workpiece 10 is cut along the planned dividing line 13 .

The imaging unit 140 images the workpiece 10 held on the holding table 111. In the modified example, the imaging unit 140 is fixed at a position parallel to the laser beam irradiation unit 114 in the X-axis direction. The imaging unit 140 is a camera using a CCD or CMOS image sensor that images the workpiece 10 held on the holding table 111, and includes an infrared camera and the like. The imaging unit 140 images the workpiece 10 to obtain an image for performing alignment for positioning the workpiece 10 and the laser beam irradiation unit 114, and outputs the obtained image to the control unit 190. .

The protective film coating and cleaning unit 150 corresponds to the protective film coating unit 50 and the cleaning unit 70, and is a unit that coats the workpiece 10 with the water-soluble protective film 20 and washes the workpiece 10 with water. The protective film coating and cleaning unit 150 accommodates a holding table 151, a clamp member 152, a water-soluble resin supply nozzle 154, and a cleaning nozzle 156. Equipped with a coating and cleaning room.

The holding table 151 suction-holds the back surface 15 side of the workpiece 10 to the holding table 51 via the adhesive tape 31 . The holding table 151 is rotatable around a rotation axis parallel to the Z-axis. The clamp member 152 fixes the outer periphery of the annular frame 30.

The water-soluble resin supply nozzle 154 is movable on the XY plane between an operating position located above the holding table 151 and a retracted position spaced apart from above the holding table 151. The water-soluble resin supply nozzle 154 drips water-soluble resin onto the surface 12 of the workpiece 10 held on the holding table 151. The water-soluble resin supply nozzle 154 reciprocates in the radial direction of the workpiece 10 held on the holding table 151 while dropping the water-soluble resin.

The cleaning nozzle 156 is movable on the XY plane between an operating position located above the holding table 151 and a retracted position spaced apart from above the holding table 151. The cleaning nozzle 156 supplies water toward the surface 12 of the workpiece 10 held on the holding table 151. The cleaning nozzle 156 reciprocates in the radial direction of the workpiece 10 held on the holding table 151 while supplying water.

The protective film coating unit that coats the workpiece 10 with the water-soluble protective film 20 and the cleaning unit that washes the workpiece 10 with water are a dual-purpose protective film coating and cleaning unit 150 in the modified example. In the invention, it may be a separate unit. Further, the protective film coating and cleaning unit 150 may further include an air supply unit that blows air to the workpiece 10 in order to dry the workpiece 10 after coating and cleaning.

The storage cassette 40 is placed on the top surface 171 of the mounting table 170 . The mounting surface 171 is movable up and down in the Z-axis direction. The mounting table 170 moves the storage cassette 40 placed on the mounting surface 171 in the Z-axis direction. The storage cassette 40 is transported between various processing devices and installed in the various processing devices. In a modified example, the accommodation cassette 40 is placed on a mounting table 170 of the laser processing apparatus 100, as shown in FIG. Furthermore, when the storage cassette 40 is transported to the cutting device 200 shown in FIG. 13, which will be described later, it is placed on the mounting table 270 of the cutting device 200.

The transport unit 180 is a unit that transports the workpiece 10 between the storage cassette 40 placed on the mounting table 170, the holding table 111, and the protective film coating and cleaning unit 150. The transport unit 180 is provided on a wall or the like that constitutes the ceiling of the main body of the laser processing apparatus 100 so as to be movable in the X-axis direction and the Y-axis direction.

The transport unit 180 takes out the workpiece 10 before laser processing from the storage cassette 40 placed on the mounting table 170 and places it on the holding table 151 of the protective film coating and cleaning unit 150 . The transport unit 180 transports the workpiece 10 coated with the water-soluble protective film 20 by the protective film coating and cleaning unit 150 from the holding table 151 to the laser processing unit 110 . Place it on. The transport unit 180 transports the workpiece 10 after laser processing from the holding table 111 to the protective film coating and cleaning unit 150 and places it on the holding table 151 of the protective film coating and cleaning unit 150 . The transport unit 180 stores the workpiece 10 that has been cleaned by the protective film coating and cleaning unit 150 and coated again with the water-soluble protective film 20 into the storage cassette 40 placed on the mounting table 170 .

The control unit 190 controls each of the above-described components of the laser processing apparatus 100 and causes the laser processing apparatus 100 to perform a processing operation on the workpiece 10. The control unit 190 is a computer including an arithmetic processing device as a calculation means, a storage device as a storage means, and an input/output interface device as a communication means. The arithmetic processing device includes, for example, a microprocessor such as a CPU (Central Processing Unit). The storage device includes a memory such as ROM (Read Only Memory) or RAM (Random Access Memory). The arithmetic processing device performs various calculations based on a predetermined program stored in the storage device. The arithmetic processing device outputs various control signals to each of the above-mentioned components via the input/output interface device according to the arithmetic results, thereby controlling the laser processing apparatus 100. The control unit 190 is connected to, for example, a display means for displaying the status of the machining operation, an operation means used by the operator to register machining content information, and the like.

In the first coating step 1 of the modified example, the surface 12 of the workpiece 10 is coated with a water-soluble resin by the protective film coating and cleaning unit 150. The procedure for applying the water-soluble resin by the protective film coating and cleaning unit 150 is the same as the procedure by the protective film coating unit 50 in the first coating step 1 of the embodiment, so the explanation will be omitted.

In laser processing step 2 of the modified example, laser processing grooves 21 are formed by the laser processing unit 110 along the dividing line 13 formed on the surface 12 of the workpiece 10 . The procedure for forming the laser processing groove 21 by the laser processing unit 110 is the same as the procedure performed by the laser processing unit 60 in laser processing step 2 of the embodiment, and therefore the description thereof will be omitted.

In the modified protective film cleaning step 3, the protective film coating and cleaning unit 150 removes the water-soluble protective film 20 covering the surface 12 of the workpiece 10 by washing with water. The procedure for cleaning and removing the water-soluble protective film 20 with water by the protective film coating and cleaning unit 150 is the same as the procedure performed by the cleaning unit 70 in the protective film cleaning step 3 of the embodiment, and therefore the description thereof will be omitted.

In the second coating step 4 of the modified example, the surface 12 of the workpiece 10 and the laser processing groove 21 are coated with a water-soluble resin by the protective film coating and cleaning unit 150. The procedure for applying the water-soluble resin by the protective film coating and cleaning unit 150 is the same as the first coating step 1, so the description thereof will be omitted.

(Composition of cutting device)
The configuration of the cutting device 200 that performs the cutting step 5 and the additional cleaning step 6 will be described. FIG. 13 is a perspective view showing a configuration example of a cutting device 200 that performs the cutting step 5 and the additional cleaning step 6 shown in FIG. 11. In the cutting device 200 of the modified example, the processing feed direction is the X-axis direction, the index feed direction is the Y-axis direction, and the cutting feed direction is the Z-axis direction.

The cutting device 200 includes a holding table 210, a cutting unit 220, an X-axis movement unit (not shown), a Y-axis movement unit 230, a Z-axis movement unit 240, a cleaning unit 250, and an imaging unit 260. , and a mounting table 270.

The holding table 210 holds the workpiece 10 on a holding surface 211 . A plurality of clamp members 212 (see FIG. 14) are arranged around the holding table 210 to clamp the annular frame 30 that supports the workpiece 10. The holding table 210 is rotated around the axis of a rotating shaft member 213 (see FIG. 14) that supports the holding table 210. The holding table 210 is moved in the X-axis direction by an unillustrated X-axis movement unit between a processing area below the cutting unit 220 and an area where the workpiece 10 is carried in and out from below the cutting unit 220. will be moved to

The cutting unit 220 is a cutting means that is detachably attached with a cutting blade 221 that cuts the workpiece 10 held on the holding table 210 and divides it into a plurality of chips 17 . The cutting unit 220 is installed on a pillar that stands up from the main body of the apparatus via a Y-axis movement unit 230 and a Z-axis movement unit 240. The cutting unit 220 is movable in the Y-axis direction by a Y-axis movement unit 230 and in the Z-axis direction by a Z-axis movement unit 240 with respect to the workpiece 10 held on the holding table 210. be. The cutting unit 220 can position the cutting blade 221 at any position on the holding surface 211 of the holding table 210 using the Y-axis movement unit 230 and the Z-axis movement unit 240. The cutting unit 220 includes a cutting blade 221, a spindle housing 222, a spindle 223 (see FIG. 14), a mount flange 224 (see FIG. 14) attached to the spindle 223 and to which the cutting blade 221 is fixed, and a cutting water supply unit. 225 (see FIG. 14).

The cutting blade 221 is an extremely thin cutting whetstone having a substantially ring shape. In a modified example, the cutting blade 221 is a so-called hub blade, and includes a circular base mounted on a mount flange 224 fixed to a spindle 223, and a circular base having a predetermined thickness disposed on the outer periphery of the circular base. It is equipped with an annular cutting blade. The circular base is made of conductive metal. The cutting blade is made of abrasive grains such as diamond or CBN (Cubic Boron Nitride), and a bond material such as metal or resin.

The spindle housing 222 is supported via a Y-axis moving unit 230 and a Z-axis moving unit 240 on a pillar that stands up from the apparatus main body. The spindle housing 222 is provided movably in the Z-axis direction by a Y-axis movement unit 230 and a Z-axis movement unit 240. The spindle housing 222 is movable in the Y-axis direction by a Y-axis movement unit 230 and in the Z-axis direction by a Z-axis movement unit 240 with respect to the workpiece 10 held on the holding table 210. be.

The spindle 223 is provided within the spindle housing 222 so as to be freely rotatable around its axis. The spindle 223 is rotated by being driven by a spindle motor (not shown) or the like. The cutting blade 221 is attached to the tip of the spindle 223 via a mount flange 224. In the modification, the axes of the spindle 223 and the cutting blade 221 of the cutting unit 220 are set in a direction parallel to the Y-axis direction.

The cutting water supply unit 225 includes a cutting water supply nozzle 226 and a water supply source (not shown). The cutting water supply nozzle 226 is fixed to the spindle housing 222 so as to move integrally with the spindle housing 222. The cutting water supply nozzle 226 is connected to a water supply source (not shown). The water supply source includes, for example, a tank that stores cutting water and a pump that supplies cutting water from the tank to the cutting water supply nozzle 226. The cutting water supply nozzle 226 supplies cutting water supplied from a water supply source to the workpiece 10 and the cutting blade 221 during cutting by the cutting unit 220 .

The cleaning unit 250 is a unit that cleans the workpiece 10 after cutting with water. The cleaning unit 250 includes a holding table 251, a clamp member 252, a rotating shaft member 253 (see FIG. 16), a cleaning nozzle 256, and a cleaning chamber that accommodates the holding table 251 and the cleaning nozzle 256.

The holding table 251 suction-holds the back surface 15 side of the workpiece 10 to the holding table 51 via the adhesive tape 31 . The clamp member 152 fixes the outer periphery of the annular frame 30. The holding table 251 is rotatable around the axis of a rotating shaft member 253 (see FIG. 16) that supports the holding table 251.

The cleaning nozzle 256 is movable on the XY plane between an operating position located above the holding table 251 and a retracted position spaced apart from above the holding table 251. The cleaning nozzle 256 supplies water 257 (see FIG. 16) toward the surface 12 of the workpiece 10 held on the holding table 251. The cleaning nozzle 256 reciprocates in the radial direction of the workpiece 10 held on the holding table 251 while supplying water 257.

The imaging unit 260 is fixed to the cutting unit 220 so as to move integrally with the cutting unit 220. The imaging unit 260 is a camera using a CCD or CMOS image sensor that images the workpiece 10 held on the holding table 210, and includes an infrared camera and the like. The imaging unit 260 images the workpiece 10 to obtain an image for performing alignment for positioning the workpiece 10 and the cutting blade 221, and outputs the obtained image to the control unit 290.

The storage cassette 40 is placed on the top surface 271 of the mounting table 270 . The mounting surface 271 is movable up and down in the Z-axis direction. The mounting table 270 moves the storage cassette 40 placed on the mounting surface 271 in the Z-axis direction.

The control unit 290 controls each of the above-mentioned components of the cutting device 200, and causes the cutting device 200 to perform a machining operation on the workpiece 10. The control unit 290 is a computer including an arithmetic processing device as a calculation means, a storage device as a storage means, and an input/output interface device as a communication means. The arithmetic processing device includes, for example, a microprocessor such as a CPU. The storage device includes memory such as ROM or RAM. The arithmetic processing device performs various calculations based on a predetermined program stored in the storage device. The arithmetic processing device controls the cutting device 200 by outputting various control signals to each of the above-mentioned components via the input/output interface device according to the arithmetic results. The control unit 290 is connected to, for example, a display means for displaying the status of machining operations, an operation means used by an operator to register machining content information, and the like.

(Cutting step 5)
FIG. 14 is a side view, partially in cross section, of an example of the cutting step 5 shown in FIG. 11. FIG. 15 is a sectional view of a main part of the workpiece 10 showing one state after the cutting step 5 in FIG. 14. As shown in FIGS. 14 and 15, in the cutting step 5, a cutting blade 221 is inserted into the center of the laser processing groove 21 while supplying water 227 to the surface 12 of the workpiece 10 coated with the water-soluble protective film 20. This is a step of removing the water-soluble protective film 20 with water 227 while forming the dividing grooves 23. Cutting step 5 is carried out using the cutting device 200 that cuts the workpiece 10 with the cutting blade 221 while supplying water 227 to the workpiece 10 after the workpiece 10 is carried out from the laser processing device 100 .

In the cutting step 5 of the modified example, a cutting water supply unit 225 supplies water 227 to the surface 12 of the workpiece 10 coated with the water-soluble protective film 20 . Furthermore, in the cutting step 5 of the modified example, the cutting blade 221 of the cutting unit 220 forms a dividing groove 23 in the center of the laser-processed groove 21 of the workpiece 10 .

In the cutting step 5, first, the back surface 15 side of the workpiece 10 is suction-held to the holding surface 211 of the holding table 210 via the adhesive tape 31, and the outer peripheral portion of the annular frame 30 is fixed with the clamp member 212. In cutting step 5, next, the cutting unit 220 and the workpiece 10 are aligned. More specifically, an unillustrated X-axis direction movement unit moves the holding table 210 to the processing area below the cutting unit 220, photographs the workpiece 10 with the imaging unit 260, and aligns the cutting blade. The processing point 221 is aligned with the dividing line 13 of the workpiece 10.

In cutting step 5, the cutting water supply nozzle 226 of the cutting water supply unit 225 starts supplying water 227 toward the surface 12 of the workpiece 10. In the cutting step 5, next, while relatively moving the holding table 210 and the cutting blade 221 of the cutting unit 220 along the dividing line 13 by the Y-axis direction movement unit 230 and the Z-axis direction movement unit 240, The cutting blade 221 cuts until it reaches the adhesive tape 31 to form the dividing groove 23.

The water-soluble protective film 20 covering the surface 12 of the workpiece 10 is removed by water 227 supplied from the cutting water supply unit 225 during cutting by the cutting blade 221 . As shown in FIG. 15, even if a part of the water-soluble protective film 20 on the surface 12 of the workpiece 10 cannot be completely removed, by performing the additional cleaning step 6, the workpiece 10 can be removed. Water-soluble protective coating 20 can be removed from surface 12.

(Additional cleaning step 6)
FIG. 16 is a side view, partially in cross section, of an example of the additional cleaning step 6 shown in FIG. 11. FIG. 17 is a sectional view of a main part of the workpiece 10 showing one state after the additional cleaning step 6 in FIG. 16. Additional cleaning step 6 is performed after cutting step 5 has been performed. As shown in FIGS. 16 and 17, the additional cleaning step 6 is a step in which water 257 is supplied to the workpiece 10 by a cleaning unit 250 included in the cutting apparatus 200 to clean the surface 12 of the workpiece 10.

In the additional cleaning step 6 of the modified example, first, the back surface 15 side of the workpiece 10 is suction-held on the holding table 251 via the adhesive tape 31, and the outer peripheral part of the annular frame 30 is fixed with the clamp member 252. In the additional cleaning step 6, water 257 is then supplied from the cleaning nozzle 256 toward the surface 12 of the workpiece 10 while the holding table 251 is rotated around the axis by the rotating shaft member 253. The water 257 is pressurized water whose pressure is adjusted to about 10 to 12 MPa in a waterway upstream from the cleaning nozzle 256. The water 257 is, for example, pure water. The water 257 may be bubble water mixed with air. Alternatively, cleaning may be performed using a so-called two-fluid mixture of water and air.

The cleaning nozzle 256 reciprocates in the radial direction of the workpiece 10 while supplying water 257. The supplied water 257 flows over the surface 12 of each device 14 of the workpiece 10 from the center toward the outer periphery due to the centrifugal force generated by the rotation of the holding table 251. The water-soluble protective film 20 covering the wafer is washed. By cleaning the water-soluble protective film 20 covering the surface 12 of each device 14 of the workpiece 10, the surface 12 of the device 14 is exposed.

As explained above, in the method of processing the workpiece 10 according to the embodiment and the modified example, after the laser processing, the water-soluble protective film 20 is cleaned and removed, and then the surface 12 of the workpiece 10 is re-applied to the surface 12 of the workpiece 10. A water-soluble protective film 20 is applied. Thereby, while removing the debris 22, the surface 12 of the workpiece 10 can be protected even when the workpiece 10 is stored for a predetermined period of time or more after being carried out from the laser processing apparatus and before being cut. Further, the water-soluble protective film 20 coated for storage can be removed in a cutting process (for example, cutting step 5 of the modified example) in which cutting water (water 227) is supplied.

Note that the present invention is not limited to the above embodiments. That is, various modifications can be made without departing from the gist of the invention.

10 Workpiece 12 Surface 13 Planned division line 14 Device 20 Water-soluble protective film 21 Laser processing groove 22 Debris 23 Division groove 50 Protective film coating unit 55 Water-soluble resin 60 Laser processing unit 65 Laser beam 70 Cleaning unit 75 Water 100 Laser processing device 110 Laser processing unit 150 Protective film coating and cleaning unit 200 Cutting device 220 Cutting unit 221 Cutting blade 225 Cutting water supply unit 250 Cleaning unit

Claims (4)

A method for processing a workpiece in which a device is formed in a region defined by a planned dividing line on a surface, the method comprising:
a first coating step of coating the surface of the workpiece with a water-soluble protective film;
After performing the first coating step, a laser beam having a wavelength that is absorbent to the workpiece is irradiated from the surface of the workpiece along the planned dividing line to create laser-processed grooves along the planned dividing line. a laser processing step of forming on the surface of the workpiece;
After performing the laser processing step, a protective film cleaning step of cleaning the surface of the workpiece and removing debris generated in the laser processing step together with the water-soluble protective film;
After carrying out the protective film cleaning step, a second coating step of again coating the surface of the workpiece and the laser processing groove with the water-soluble protective film;
After successively performing the first coating step, the laser processing step, the protective film cleaning step, and the second coating step,
Cutting in which the water-soluble protective film is removed using water while supplying water to the surface of the workpiece coated with the water-soluble protective film and forming a dividing groove with a cutting blade in the center of the laser processing groove. step and
A method of processing a workpiece comprising: Using a laser processing device that includes a laser processing unit that processes a workpiece, a protective film coating unit that coats the workpiece with the water-soluble protective film, and a cleaning unit that washes the workpiece with water,
After successively performing the first coating step, the laser processing step, the protective film cleaning step, and the second coating step,
Carrying out the workpiece from the laser processing device,
Using a cutting device that cuts the workpiece with a cutting blade while supplying water to the workpiece, the cutting blade is placed in the center of the laser processing groove while supplying water to the surface of the workpiece coated with the water-soluble protective film. performing the cutting step of removing the water-soluble protective film with the water while forming a dividing groove with the water;
The method for processing a workpiece according to claim 1. The method for processing a workpiece according to claim 2, further comprising an additional cleaning step of supplying water to the workpiece with a cleaning unit included in the cutting device to clean the surface of the workpiece after performing the cutting step. . After the second coating step and before the cutting step, the workpiece whose surface and the laser-processed grooves are coated with the water-soluble protective film is stored for a predetermined period of time or longer.
The method for processing a workpiece according to any one of claims 1 to 3.

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