JP2019212784A - Wafer processing method - Google Patents

Abstract

To form a device chip without deteriorating quality.SOLUTION: A wafer processing method for dividing a wafer in which a plurality of devices are formed in each region on a surface partitioned by division schedule lines into individual device chips comprises a polyolefin-based sheet arranging step, an integrating step, a dividing step, and a picking-up step. The polyolefin-based sheet arranging step positions the wafer in an opening of a frame and arranges a polyolefin-based sheet in a rear surface of the wafer and an outer periphery of the frame, the opening housing the wafer. The integrating step heats and presses the polyolefin-based sheet, and integrates the wafer and the frame via the polyolefin-based sheet. The dividing step divides the wafer into individual device chips by cutting the wafer along division schedule lines using a cutting device rotatably including a cutting blade. The picking-up step pushes up the device chip by spraying air and picks up the device chip from the polyolefin-based sheet.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a wafer processing method that divides a wafer formed in each region of a surface defined by a plurality of devices by dividing lines into individual devices.

  In the manufacturing process of a device chip used for an electronic device such as a mobile phone or a personal computer, first, a plurality of intersecting division lines (streets) are set on the surface of a wafer made of a material such as a semiconductor. Then, devices such as an IC (Integrated Circuit) and an LSI (Large-scale Integrated Circuit) are formed in each region partitioned by the planned division lines.

  Thereafter, an adhesive tape called a dicing tape attached to an annular frame having an opening is attached to the back surface of the wafer, and the wafer, the adhesive tape, and the annular frame are integrated. Forming a frame unit. Then, when the wafer included in the frame unit is processed and divided along the planned dividing lines, individual device chips are formed.

  For example, a cutting device is used for dividing the wafer. The cutting apparatus includes a chuck table that holds a wafer via an adhesive tape, a cutting unit that cuts the wafer, and the like. The cutting unit includes a cutting blade having an annular grindstone portion, and a spindle that is pierced through a central through hole of the cutting blade and rotates the cutting blade.

  When cutting a wafer, the frame unit is placed on the chuck table, the wafer is held on the chuck table via an adhesive tape, the cutting blade is rotated by rotating the spindle, and the cutting unit is moved to a predetermined height. Lower to position. Then, the chuck table and the cutting unit are relatively moved along the direction parallel to the upper surface of the chuck table, and the wafer is cut by the cutting blade along the scheduled division line. Then, the wafer is divided.

  Thereafter, the frame unit is taken out from the cutting device, and the adhesive tape is subjected to a process such as irradiating ultraviolet rays to reduce the adhesive force of the adhesive tape, and the device chip is picked up. As a processing apparatus with high device chip production efficiency, there is known a cutting apparatus capable of continuously performing wafer division and ultraviolet irradiation on an adhesive tape with one apparatus (see Patent Document 1). The device chip picked up from the adhesive tape is mounted on a predetermined wiring board or the like.

Japanese Patent No. 3076179

  An adhesive tape contains a base material layer and the paste layer arrange | positioned on this base material layer. In the cutting apparatus, in order to reliably divide the wafer, the cutting unit is positioned at a predetermined height so that the lower end of the cutting blade reaches a position lower than the lower surface of the wafer. Therefore, the cutting blade for cutting the wafer also cuts the adhesive layer of the adhesive tape. Accordingly, when cutting the wafer, cutting waste derived from the glue layer is generated together with cutting waste derived from the wafer.

  When the wafer is cut, cutting fluid is supplied to the wafer and the cutting blade, but the cutting waste generated by the cutting is taken into the cutting fluid and diffused on the surface of the wafer. Here, the cutting waste derived from the glue layer is easily reattached to the surface of the device, and it is not easy to remove in a subsequent wafer cleaning process or the like. Therefore, when the cutting waste derived from the glue layer adheres, the deterioration of the quality of the device chip becomes a problem.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a wafer processing method in which cutting scraps are less likely to adhere to the surface of the device and deterioration in the quality of the device chip is suppressed. That is.

  According to one aspect of the present invention, a plurality of devices is a wafer processing method in which a wafer formed in each region of a surface partitioned by a division planned line is divided into individual device chips, and the wafer is accommodated. Positioning the wafer in the opening of the frame having an opening, disposing a polyolefin-based sheet on the back surface of the wafer and the outer periphery of the frame, heating and pressing the polyolefin-based sheet, The wafer and the frame are integrated through the polyolefin sheet, and the wafer is individually cut by cutting the wafer along a division line using a cutting device having a cutting blade rotatably. By dividing into device chips and by blowing air from the polyolefin sheet side Pushing up the device chip, the processing method of the wafer, comprising and a pickup step for picking up the device chip from the polyolefin sheet is provided.

  Preferably, in the integration step, after the integration, the polyolefin sheet protruding from the outer periphery of the frame is removed.

  Preferably, in the pickup step, the polyolefin-based sheet is expanded to widen the space between the device chips.

  Preferably, the polyolefin-based sheet is any one of a polyethylene sheet, a polypropylene sheet, and a polystyrene sheet.

  Further preferably, in the integration step, when the polyolefin-based sheet is the polyethylene sheet, the heating temperature is 120 ° C. to 140 ° C., and when the polyolefin-based sheet is the polypropylene sheet, the heating temperature is 160 When the polyolefin sheet is the polystyrene sheet, the heating temperature is 220 ° C to 240 ° C.

  Preferably, the wafer is made of any one of Si, GaN, GaAs, and glass.

  In the wafer processing method according to one aspect of the present invention, when forming the frame unit, a pressure-sensitive adhesive tape having a glue layer is not used and a frame and a wafer are used using a polyolefin-based sheet not having a glue layer. Integrate. An integration process for integrating the frame and the wafer via the polyolefin-based sheet is realized by heating and pressing.

  After performing the integration process, the wafer is cut with a cutting blade to divide the wafer into individual device chips, and each device chip is pushed up by blowing air from the polyolefin sheet side. To pick up. Each picked-up device chip is mounted on a predetermined mounting target. When the device chip is pushed up by air during pick-up, the load on the device chip when peeling from the polyolefin-based sheet can be reduced.

  When the wafer is cut, the cutting blade also cuts into the polyolefin sheet under the wafer, so that cutting waste derived from the polyolefin sheet is generated. However, since the polyolefin-based sheet does not have a glue layer, even if the cutting waste is taken into the cutting water and diffused on the surface of the wafer, the cutting waste is relatively difficult to adhere to the wafer. Moreover, even if cutting waste adheres to the wafer, it is easily removed by a subsequent cleaning process or the like.

  That is, according to one aspect of the present invention, it is possible to form a frame unit using a polyolefin-based sheet that does not have a glue layer by thermocompression bonding, and no cutting waste with high adhesive strength is generated when cutting a wafer. The deterioration of the quality of the device chip due to is suppressed.

  Therefore, according to one aspect of the present invention, there is provided a wafer processing method in which cutting scraps are less likely to adhere to the surface of a device, and degradation of device chip quality is suppressed.

It is a perspective view which shows a wafer typically. It is a perspective view which shows typically a mode that a wafer and a frame are positioned on the holding surface of a chuck table. It is a perspective view which shows typically a polyolefin-type sheet | seat arrangement | positioning process. It is a perspective view which shows an example of an integration process typically. FIG. 5A is a perspective view schematically showing a state in which a polyolefin-based sheet is cut, and FIG. 5B is a perspective view schematically showing the formed frame unit. It is a perspective view which shows a division | segmentation process typically. It is a perspective view which shows typically carrying in of the frame unit to a pick-up apparatus. FIG. 8A is a cross-sectional view schematically showing the frame unit fixed on the frame support, and FIG. 8B is a cross-sectional view schematically showing the pickup process.

  Embodiments according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a wafer processed by the processing method according to the present embodiment will be described. FIG. 1 is a perspective view schematically showing the wafer 1. The wafer 1 is made of, for example, a material such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or another semiconductor, or a material such as sapphire, glass, or quartz. A substantially disk-shaped substrate.

  The surface 1a of the wafer 1 is partitioned by a plurality of division lines 3 arranged in a lattice pattern. In addition, a device 5 such as an IC (Integrated Circuit) or an LED (Light Emitting Diode) is formed in each region partitioned by the division lines 3 on the surface 1a of the wafer 1. In the processing method of the wafer 1 according to the present embodiment, individual device chips are formed by cutting the wafer 1 along the division line 3 and dividing it.

  The wafer 1 is cut by a cutting device. Before the wafer 1 is carried into the cutting device, the wafer 1, the polyolefin-based sheet, and the frame are integrated to form a frame unit. The wafer 1 is carried into a cutting device in the state of a frame unit and cut. Each formed device chip is supported by a polyolefin-based sheet. Thereafter, the space between the device chips is expanded by expanding the polyolefin-based sheet, and the device chips are picked up by the pickup device.

  The annular frame 7 (see FIG. 2 and the like) is formed of a material such as metal, for example, and includes an opening 7 a having a diameter larger than the diameter of the wafer 1. When forming the frame unit, the wafer 1 is positioned in the opening 7a of the frame 7 and accommodated in the opening 7a.

  The polyolefin-based sheet 9 (see FIG. 3 etc.) is a resin-based sheet having flexibility, and the front and back surfaces are flat. And it has a diameter larger than the outer diameter of the frame 7, and does not have a glue layer. The polyolefin-based sheet 9 is a polymer sheet synthesized using an alkene as a monomer, and is, for example, a sheet transparent or translucent to visible light, such as a polyethylene sheet, a polypropylene sheet, or a polystyrene sheet. However, the polyolefin sheet 9 is not limited to this, and may be opaque.

  Since the polyolefin sheet 9 does not have adhesiveness, it cannot be attached to the wafer 1 and the frame 7 at room temperature. However, since the polyolefin-based sheet 9 has thermoplasticity, when heated to a temperature near the melting point in a state of being bonded to the wafer 1 and the frame 7 while applying and pressing a predetermined pressure, the polyolefin sheet 9 is partially melted and the wafer 1 and Can be adhered to the frame 7. Therefore, in the processing method of the wafer 1 according to the present embodiment, the wafer 1, the frame 7, and the polyolefin-based sheet 9 are integrated to form a frame unit by heating and pressing as described above.

  Next, each process of the processing method of the wafer 1 which concerns on this embodiment is demonstrated. First, in order to prepare for integrating the wafer 1, the polyolefin-based sheet 9, and the frame 7, a polyolefin-based sheet disposing step is performed. FIG. 2 is a perspective view schematically showing how the wafer 1 and the frame 7 are positioned on the holding surface 2 a of the chuck table 2. As shown in FIG. 2, the polyolefin-based sheet disposing step is performed on the chuck table 2 having the holding surface 2a on the top.

  The chuck table 2 includes a porous member having a diameter larger than the outer diameter of the frame 7 in the upper center. The upper surface of the porous member becomes the holding surface 2 a of the chuck table 2. As shown in FIG. 3, the chuck table 2 has an exhaust passage having one end communicating with the porous member, and a suction source 2b is disposed on the other end side of the exhaust passage. The exhaust path is provided with a switching unit 2c that switches between a communication state and a disconnected state. When the switching unit 2c is in a communication state, negative pressure generated by the suction source 2b on an object to be held placed on the holding surface 2a. The pressure acts, and the object to be held is sucked and held on the chuck table 2.

  In the polyolefin-based sheet arranging step, first, as shown in FIG. 2, the wafer 1 and the frame 7 are placed on the holding surface 2 a of the chuck table 2. At this time, the wafer 1 is positioned in the opening 7 a of the frame 7 with the surface 1 a side of the wafer 1 facing downward. Next, the polyolefin sheet 9 is disposed on the back surface 1 b of the wafer 1 and the outer periphery of the frame 7. FIG. 3 is a perspective view schematically showing a polyolefin-based sheet disposing step. As shown in FIG. 3, a polyolefin-based sheet 9 is disposed on both the wafer 1 and the frame 7 so as to cover them.

  In the polyolefin sheet disposing step, a polyolefin sheet 9 having a diameter larger than the holding surface 2a of the chuck table 2 is used. When a negative pressure by the chuck table 2 is applied to the polyolefin-based sheet 9 in an integration process performed later, if the entire holding surface 2a is not covered with the polyolefin-based sheet 9, the negative pressure leaks from the gap. This is because the pressure cannot be properly applied to the polyolefin sheet 9.

  In the processing method of the wafer 1 according to the present embodiment, next, an integration process is performed in which the polyolefin sheet 9 is heated and pressed to integrate the wafer 1 and the frame 7 via the polyolefin sheet 9. . FIG. 4 is a perspective view schematically showing an example of the integration process. In FIG. 4, what can be visually recognized through the polyolefin-type sheet | seat 9 which is transparent or semi-transparent with respect to visible light is shown with a broken line.

  In the integration step, first, the switching portion 2c of the chuck table 2 is operated to establish a communication state, the suction source 2b is connected to the porous member on the upper side of the chuck table 2, and the negative pressure by the suction source 2b is applied to the polyolefin sheet 9. Make it work. Then, the polyolefin-based sheet 9 comes into close contact with the wafer 1 and the frame 7 due to atmospheric pressure.

  Next, the polyolefin sheet 9 is heated and further pressed to perform thermocompression bonding. The heating and pressing of the polyolefin-based sheet 9 are performed using a heat roller 4 having a heat source therein as shown in FIG.

  The heat roller 4 is heated to a predetermined temperature, and the heat roller 4 is placed on one end of the holding surface 2 a of the chuck table 2. Then, the heat roller 4 is rotated, and the heat roller 4 is rolled on the chuck table 2 from the one end to the other end. Then, the polyolefin sheet 9 is thermocompression bonded to the wafer 1 and the frame 7. At this time, a force is applied in a direction in which the polyolefin sheet 9 is pushed down by the heat roller 4, and thermocompression bonding is performed at a pressure larger than atmospheric pressure. In addition, it is preferable to coat the surface of the heat roller 4 with a fluororesin.

  Further, the polyolefin sheet 9 may be heated and pressed using an iron-like pressing member having a heat source inside and having a flat bottom plate instead of the heat roller 4. In this case, the pressing member is heated to a predetermined temperature to form a hot plate, and the polyolefin sheet 9 held on the chuck table 2 is pressed from above by the pressing member.

  After thermocompression bonding of the polyolefin-based sheet 9, the switching portion 2c is operated to disconnect the porous member of the chuck table 2 from the suction source 2b, and the suction by the chuck table 2 is released.

  Next, the polyolefin sheet 9 protruding from the outer periphery of the frame 7 is cut and removed. FIG. 5A is a perspective view schematically showing a state in which the polyolefin-based sheet 9 is cut. For cutting, an annular cutter 6 is used as shown in FIG. The cutter 6 includes a through hole and is rotatable around a rotation shaft that is pierced through the through hole.

  First, the annular cutter 6 is positioned above the frame 7. At this time, the rotation axis of the cutter 6 is aligned with the radial direction of the chuck table 2. Next, the cutter 6 is lowered, the polyolefin sheet 9 is sandwiched between the frame 7 and the cutter 6, and the polyolefin sheet 9 is cut. As a result, cut marks 9 a are formed in the polyolefin-based sheet 9.

  Further, the cutter 6 makes a round around the opening 7a of the frame 7 along the frame 7, and a predetermined region of the polyolefin-based sheet 9 is surrounded by the cut mark 9a. And the polyolefin-type sheet 9 of the area | region of the outer peripheral side of the cutting trace 9a is removed so that this area | region of the polyolefin-type sheet 9 may be left. Then, the unnecessary part of the polyolefin-type sheet | seat 9 including the area | region which protruded from the outer periphery of the flame | frame 7 can be removed.

  An ultrasonic cutter may be used for cutting the polyolefin-based sheet, and a vibration source that vibrates the above-described annular cutter 6 at a frequency of an ultrasonic band may be connected to the cutter 6. Further, when the polyolefin sheet 9 is cut, the polyolefin sheet 9 may be cooled and cured in order to facilitate cutting. Thus, the frame unit 11 in which the wafer 1 and the frame 7 are integrated with each other via the polyolefin-based sheet 9 is formed. FIG. 5B is a perspective view schematically showing the formed frame unit 11.

  In addition, when implementing an integration process, the polyolefin-type sheet | seat 9 is preferably heated to the temperature below the melting | fusing point. This is because if the heating temperature exceeds the melting point, the polyolefin sheet 9 may be dissolved and the sheet shape may not be maintained. The polyolefin-based sheet 9 is preferably heated to a temperature equal to or higher than its softening point. This is because the integration process cannot be performed properly unless the heating temperature reaches the softening point. That is, the polyolefin sheet 9 is preferably heated to a temperature not lower than its softening point and not higher than its melting point.

  Furthermore, some polyolefin-based sheets 9 may not have a clear softening point. Therefore, when performing the integration step, the polyolefin-based sheet 9 is preferably heated to a temperature that is 20 ° C. lower than its melting point and lower than its melting point.

  For example, when the polyolefin-type sheet | seat 9 is a polyethylene sheet, heating temperature shall be 120 to 140 degreeC. Moreover, when this polyolefin-type sheet | seat 9 is a polypropylene sheet, heating temperature shall be 160 to 180 degreeC. Furthermore, when the polyolefin-type sheet | seat 9 is a polystyrene sheet, heating temperature shall be 220 to 240 degreeC.

  Here, the heating temperature refers to the temperature of the polyolefin-based sheet 9 when performing the integration step. For example, a heat source such as the heat roller 4 is available for a model that can set the output temperature, but even when the polyolefin sheet 9 is heated using the heat source, the temperature of the polyolefin sheet 9 is set. The output temperature may not be reached. Therefore, the output temperature of the heat source may be set higher than the melting point of the polyolefin sheet 9 in order to heat the polyolefin sheet 9 to a predetermined temperature.

  Next, in the processing method of the wafer 1 according to the present embodiment, a dividing step is performed in which the wafer 1 in the state of the frame unit 11 is cut by a cutting blade and divided. The dividing step is performed, for example, with a cutting apparatus shown in FIG. FIG. 6 is a perspective view schematically showing the dividing step.

  The cutting device 8 includes a cutting unit 10 that cuts a workpiece and a chuck table (not shown) that holds the workpiece. The cutting unit 10 includes a cutting blade 14 having an annular grindstone, and a spindle (not shown) that rotates the cutting blade 14 with its distal end passing through a central through-hole of the cutting blade 14. The cutting blade 14 includes, for example, an annular base having the through hole at the center, and an annular grindstone portion disposed on the outer peripheral portion of the annular base.

  The base end side of the spindle is connected to a spindle motor (not shown) housed in the spindle housing 12, and the cutting blade 14 can be rotated by operating the spindle motor.

  When the workpiece is cut by the cutting blade 14, heat is generated by friction between the cutting blade 14 and the workpiece. Further, when the workpiece is cut, cutting waste is generated from the workpiece. Therefore, in order to remove the heat and cutting waste generated by the cutting, cutting water such as pure water is supplied to the cutting blade 14 and the workpiece while cutting the workpiece. The cutting unit 10 includes, for example, a cutting water supply nozzle 16 that supplies cutting water to the cutting blade 14 or the like on the side of the cutting blade 14.

  When cutting the wafer 1, the frame unit 11 is placed on the chuck table, and the wafer 1 is held on the chuck table via the polyolefin-based sheet 9. Then, the chuck table is rotated to align the division line 3 of the wafer 1 with the processing feed direction of the cutting device 8. Further, the relative positions of the chuck table and the cutting unit 10 are adjusted so that the cutting blade 14 is disposed above the extension line of the planned division line 3.

  Next, the cutting blade 14 is rotated by rotating the spindle. Then, the cutting unit 10 is lowered to a predetermined height position, and the chuck table and the cutting unit 10 are relatively moved along a direction parallel to the upper surface of the chuck table. Then, the grindstone portion of the rotating cutting blade 14 comes into contact with the wafer 1 and the wafer 1 is cut, and a cutting mark 3 a along the scheduled division line 3 is formed on the wafer 1 and the polyolefin-based sheet 9.

  After cutting along one scheduled division line 3, the chuck table and the cutting unit 10 are moved in an indexing feed direction perpendicular to the machining feed direction, and the wafer 1 is similarly cut along the other scheduled division line 3. Perform cutting. After cutting along all the division lines 3 along one direction, the chuck table is rotated around an axis perpendicular to the holding surface, and along the division lines 3 along the other direction as well. Then, the wafer 1 is cut. When the wafer 1 is cut along all the planned dividing lines 3 of the wafer 1, the dividing step is completed.

  The cutting device 8 may include a cleaning unit (not shown) in the vicinity of the cutting unit 10. The wafer 1 cut by the cutting unit 10 may be transferred to the cleaning unit and cleaned by the cleaning unit. For example, the cleaning unit includes a cleaning table that holds the frame unit 11 and a cleaning water supply nozzle that can reciprocate above the frame unit 11.

  The cleaning table is rotated around an axis perpendicular to the holding surface, and a cleaning liquid such as pure water is supplied from the cleaning water supply nozzle to the wafer 1, and the cleaning water supply nozzle is reciprocated along a path passing above the center of the holding surface. When moved, the surface 1a side of the wafer 1 can be cleaned.

  When the dividing step is performed, the wafer 1 is divided into individual device chips. The formed device chip is supported by the polyolefin-based sheet 9. When cutting the wafer 1, in order to divide the wafer 1 reliably, the cutting unit 10 is set to a predetermined height so that the height position of the lower end of the cutting blade 14 is lower than the back surface 1b of the wafer 1. Positioned. Therefore, when the wafer 1 is cut, the polyolefin sheet 9 is also cut, and cutting waste derived from the polyolefin sheet 9 is generated.

  When an adhesive tape is used instead of the polyolefin-based sheet 9 for the frame unit 11, cutting waste derived from the adhesive layer of the adhesive tape is generated. In this case, the cutting waste is taken into the cutting water sprayed from the cutting water supply nozzle 16 and diffused on the surface 1 a of the wafer 1. The cutting waste derived from the glue layer easily adheres to the surface of the device 5 and is not easy to remove in a cleaning step of the wafer 1 performed after cutting. When the cutting waste derived from the glue layer adheres, the quality of the device chip to be formed becomes a problem.

  On the other hand, in the processing method of the wafer 1 according to the present embodiment, not the pressure-sensitive adhesive tape having the glue layer on the frame unit 11 but the polyolefin-based sheet 9 having no glue layer is used. Even if cutting waste derived from the polyolefin-based sheet 9 is generated, taken into cutting water and diffused on the surface of the wafer, the cutting waste is relatively difficult to adhere to the wafer 1. Further, even if cutting waste adheres to the wafer 1, it is easily removed by a subsequent cleaning process or the like. Therefore, the quality degradation of the device chip due to the cutting waste is suppressed.

  In the processing method of the wafer 1 according to the present embodiment, next, a pickup process for picking up each device chip from the polyolefin-based sheet 9 is performed. In the pickup process, a pickup device 18 shown in the lower part of FIG. 7 is used. FIG. 7 is a perspective view schematically showing the loading of the frame unit 11 into the pickup device 18.

  The pickup device 18 includes a cylindrical drum 20 having a diameter larger than the diameter of the wafer 1 and a frame holding unit 22 including a frame support 26. The frame support 26 of the frame holding unit 22 has an opening having a diameter larger than the diameter of the drum 20 and is disposed at the same height as the upper end of the drum 20. Enclose from.

  A clamp 24 is disposed on the outer peripheral side of the frame support 26. When the frame unit 11 is placed on the frame support 26 and the frame 7 of the frame unit 11 is held by the clamp 24, the frame unit 11 is fixed to the frame support 26.

  The frame support 26 is supported by a plurality of rods 28 that extend in the vertical direction, and an air cylinder 30 that raises and lowers the rods 28 is disposed at the lower end of each rod 28. The plurality of air cylinders 30 are supported by a disk-shaped base 32. When each air cylinder 30 is operated, the frame support 26 is pulled down with respect to the drum 20.

  Inside the drum 20, a push-up mechanism 34 that pushes up the device chip supported by the polyolefin-based sheet 9 from below is disposed. The push-up mechanism 34 has a function of blowing air 34a upward. Further, a collet 36 (see FIG. 8B) capable of sucking and holding the device chip is disposed above the drum 20. The push-up mechanism 34 and the collet 36 are movable in the horizontal direction along the upper surface of the frame support 26. The collet 36 is connected to the suction source 36a (see FIG. 8B) via the switching unit 36b (see FIG. 8B).

  In the pickup process, first, the air cylinder 30 is operated to adjust the height of the frame support 26 so that the height of the upper end of the drum 20 of the pickup device 18 matches the height of the upper surface of the frame support 26. To do. Next, the frame unit 11 carried out from the cutting device 8 is placed on the drum 20 and the frame support 26 of the pickup device 18.

  Thereafter, the frame 7 of the frame unit 11 is fixed on the frame support 26 by the clamp 24. FIG. 8A is a cross-sectional view schematically showing the frame unit 11 fixed on the frame support base 26. On the wafer 1, cutting marks 3a are formed and divided by the dividing step.

  Next, the air cylinder 30 is operated to lower the frame support 26 of the frame holding unit 22 with respect to the drum 20. Then, as shown in FIG. 8B, the polyolefin-based sheet 9 is expanded in the outer peripheral direction. FIG. 8B is a cross-sectional view schematically showing the pickup process.

  When the polyolefin-based sheet 9 is expanded in the outer peripheral direction, the distance between the device chips 1c supported by the polyolefin-based sheet 9 is increased. Then, it becomes difficult for the device chips 1c to come into contact with each other, and pickup of the individual device chips 1c becomes easy. Then, the device chip 1c to be picked up is determined, the push-up mechanism 34 is moved below the device chip 1c, and the collet 36 is moved above the device chip 1c.

  Thereafter, the device chip 1c is pushed up by operating the push-up mechanism 34 and blowing air 34a from the polyolefin-based sheet 9 side. And the switching part 36b is operated and the collet 36 is connected to the suction source 36a. Then, the device chip 1 c is sucked and held by the collet 36, and the device chip 1 c is picked up from the polyolefin sheet 9. The individual device chips 1c thus picked up are used after being mounted on a predetermined wiring board or the like.

  When the device chip is picked up, air 34a is blown onto the device chip from the polyolefin sheet 9 side to push up the device chip, thereby reducing the load on the device chip when the device chip is peeled off from the polyolefin sheet 9 Is done.

  As described above, according to the wafer processing method of the present embodiment, the frame unit 11 including the wafer 1 can be formed without using an adhesive tape. Therefore, even if the wafer 1 is cut, cutting waste derived from the adhesive layer of the adhesive tape is not generated, and the cutting waste does not adhere to the device chip 1c. Therefore, the quality of the device chip 1c is not deteriorated.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, the case where the polyolefin-based sheet 9 is, for example, a polyethylene sheet, a polypropylene sheet, or a polystyrene sheet has been described, but one aspect of the present invention is not limited thereto. For example, other materials may be used for the polyolefin-based sheet, and a copolymer of propylene and ethylene, an olefin-based elastomer, or the like may be used.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 1 Wafer 1a Front surface 1b Back surface 3 Scheduled division line 3a Cutting trace 5 Device 7 Frame 7a Opening 9 Polyolefin-based sheet 9a Cutting trace 11 Frame unit 2 Chuck table 2a Holding surface 2b, 36a Suction source 2c, 36b Switching part 4 Heat roller 6 Cutter 8 Cutting Device 10 Cutting Unit 12 Spindle Housing 14 Cutting Blade 16 Cutting Water Supply Nozzle 18 Pickup Device 20 Drum 22 Frame Holding Unit 24 Clamp 26 Frame Support Base 28 Rod 30 Air Cylinder 32 Base 34 Pushing Mechanism 34a Air 36 Collet

Claims (6)

A wafer processing method in which a plurality of devices divide a wafer formed in each region of a surface defined by division-scheduled lines into individual device chips,
A polyolefin-based sheet disposing step of positioning the wafer in the opening of the frame having an opening for accommodating the wafer, and disposing a polyolefin-based sheet on the back surface of the wafer and the outer periphery of the frame;
An integration step of heating and pressing the polyolefin sheet to integrate the wafer and the frame via the polyolefin sheet;
A dividing step of cutting the wafer along a predetermined dividing line by using a cutting device having a cutting blade rotatably, and dividing the wafer into individual device chips;
Picking up the device chip individually by blowing air from the polyolefin sheet side, and picking up the device chip from the polyolefin sheet;
A method for processing a wafer, comprising:   2. The wafer processing method according to claim 1, wherein in the integration step, after the integration, the polyolefin sheet protruding from the outer periphery of the frame is removed.   2. The wafer processing method according to claim 1, wherein, in the pick-up step, the polyolefin-based sheet is expanded to widen the interval between the device chips.   2. The wafer processing method according to claim 1, wherein the polyolefin sheet is any one of a polyethylene sheet, a polypropylene sheet, and a polystyrene sheet.   In the integration step, when the polyolefin-based sheet is the polyethylene sheet, the heating temperature is 120 ° C to 140 ° C, and when the polyolefin-based sheet is the polypropylene sheet, the heating temperature is 160 ° C to 180 ° C. The method for processing a wafer according to claim 4, wherein when the polyolefin-based sheet is the polystyrene sheet, the heating temperature is 220 ° C to 240 ° C.   2. The wafer processing method according to claim 1, wherein the wafer is made of any one of Si, GaN, GaAs, and glass.