JP2019212817A - 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 on a surface into individual device chips comprises a polyester-based sheet arranging step, an integrating step, a frame supporting step, a dividing step, and a picking-up step. The polyester-based sheet arranging step arranges a polyester-based sheet on a rear surface of the wafer. The integrating step heats the polyester-based sheet by applying hot air to the sheet, and integrates the wafer and the polyester-based sheet. The frame supporting step supports the polyester-based sheet by a frame composed of a first frame including an opening and a plurality of magnets and a second frame including an opening by holding an outer periphery of the polyester-based sheet between the first frame and the second frame by a magnetic force using the frame. The dividing step divides the wafer into individual device chips by cutting the wafer using a cutting device. The picking-up step pushes up the device chip by spraying air.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, there is provided a wafer processing method in which a plurality of devices divide a wafer formed in each region of a surface partitioned by a predetermined division line into individual device chips, on the back surface of the wafer. A polyester-based sheet disposing step of disposing a polyester-based sheet; and an integrating step of heating the polyester-based sheet by applying hot air to the polyester-based sheet to integrate the wafer and the polyester-based sheet; Before or after the integration step, a first frame having an opening large enough to accommodate the wafer and having a plurality of magnets, and a second frame large enough to accommodate the wafer And the polyester between the first frame and the second frame by the magnetic force generated by the magnet. A frame supporting step for supporting the polyester sheet with the frame by sandwiching the outer periphery of the system sheet, and a cutting device equipped with a cutting blade that can be rotated to cut the wafer along the division line. A dividing step of dividing the wafer into individual device chips, and a pickup step of individually pushing up the device chips by blowing air from the polyester sheet side and picking up the device chips from the polyester sheet. A featured wafer processing method is provided.

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

  Preferably, the polyester sheet is either a polyethylene terephthalate sheet or a polyethylene naphthalate sheet.

  Further preferably, in the integration step, when the polyester-based sheet is the polyethylene terephthalate sheet, the heating temperature is 250 ° C. to 270 ° C., and when the polyester-based sheet is the polyethylene naphthalate sheet, it is heated. The temperature is 160 ° C to 180 ° C.

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

  In the wafer processing method according to one embodiment of the present invention, the frame and the wafer are integrated using a polyester sheet that does not use an adhesive tape having a glue layer in the frame unit and does not have a glue layer. The integration process for integrating the polyester sheet and the wafer is realized by applying hot air to the polyester sheet.

  The wafer processing method according to one aspect of the present invention includes a first frame having an opening large enough to accommodate a wafer and a second frame having an opening large enough to accommodate the wafer. Frames are used. The first frame includes a plurality of magnets, and the first frame and the second frame are attracted to each other by a magnetic force generated by the magnets.

  In the frame supporting step, a polyester-based sheet is disposed between the first frame and the second frame, and is sandwiched between the first frame and the second frame. A polyester sheet can be supported by a frame.

  That is, even if the polyester sheet does not have a glue layer, the frame unit can be formed by integrating the wafer, the polyester sheet, and the frame by performing the integration step and the frame support step. .

  Thereafter, the wafer is cut with a cutting blade to divide the wafer into individual device chips, and air is blown from the polyester sheet side to individually push up the device chips and pick up the device chips from the polyester sheet. Each picked-up device chip is mounted on a predetermined mounting target. If the device chip is pushed up by air during pick-up, the load applied to the device chip when peeling from the polyester sheet can be reduced.

  When the wafer is cut, the cutting blade also cuts into the polyester sheet under the wafer, so that cutting waste derived from the polyester sheet is generated. However, since the polyester-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 polyester-based sheet that does not have a glue layer, and no cutting chips with high adhesive force are generated when a wafer is cut. The deterioration of quality 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 is positioned on the holding surface of a chuck table. It is a perspective view which shows a polyester-type sheet | seat arrangement | positioning process typically. It is a perspective view which shows an example of an integration process typically. FIG. 5A is a perspective view schematically showing the frame supporting step, 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 apparatus, the wafer 1, the polyester 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 polyester-based sheet. Then, the space | interval between device chips is expanded by extending a polyester-type sheet | seat, and a device chip is picked up with a pick-up apparatus.

  The annular frame 7 (see FIGS. 5A and 5B) is formed of a material such as metal, for example, and includes a first frame 7a having an opening 7b large enough to accommodate the wafer 1. The second frame 7f having an opening 7g having a size capable of accommodating the wafer 1 is constituted by two members. For example, the first frame 7a and the second frame 7f have substantially the same shape.

  The first frame 7a includes a plurality of pins 7d on the upper surface 7c. A plurality of magnets 7e are embedded in the upper surface 7c of the first frame 7a. The second frame 7f is provided with a plurality of through holes 7i penetrating in the thickness direction. When the first frame 7a and the second frame 7f are overlapped, the through hole of the second frame 7f is so fitted that the pin 7d of the first frame 7a is fitted into the through hole 7i. 7i is formed with the number, position and size corresponding to the pin 7d of the first frame 7a.

  The polyester-based sheet 9 (see FIG. 3 and the like) 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 polyester-based sheet 9 is a polymer sheet synthesized using a dicarboxylic acid (a compound having two carboxyl groups) and a diol (a compound having two hydroxyl groups) as monomers, for example, a polyethylene terephthalate sheet, or And a transparent or translucent sheet for visible light such as a polyethylene naphthalate sheet. However, the polyester sheet 9 is not limited to this, and may be opaque.

  Since the polyester sheet 9 does not have adhesiveness, it cannot be attached to the wafer 1 at room temperature. However, since the polyester-based sheet 9 has thermoplasticity, it can be partially melted and bonded to the wafer 1 when heated to a temperature near the melting point while being bonded to the wafer 1 while applying a predetermined pressure.

  In the processing method of the wafer 1 according to this embodiment, the polyester sheet 9 is bonded to the back surface 1b side of the wafer 1 by heating, and the outer periphery of the polyester sheet 9 is bonded to the first frame 7a and the second frame 7f. The frame unit is formed by sandwiching between the two.

  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 and the polyester sheet 9, a polyester sheet disposing step is performed. FIG. 2 is a perspective view schematically showing how the wafer 1 is positioned on the holding surface 2 a of the chuck table 2. As shown in FIG. 2, the polyester-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 wafer 1 at 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 polyester sheet disposing step, first, the wafer 1 is placed on the holding surface 2a of the chuck table 2 as shown in FIG. At this time, the front surface 1a side of the wafer 1 is directed downward. Next, the polyester sheet 9 is disposed on the back surface 1 b of the wafer 1. FIG. 3 is a perspective view schematically showing a polyester-based sheet disposing step. As shown in FIG. 3, a polyester sheet 9 is disposed on the wafer 1 so as to cover the wafer 1.

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

  In the processing method of the wafer 1 according to the present embodiment, next, the polyester sheet 9 is heated by applying hot air to the polyester sheet 9 to integrate the wafer 1 and the polyester sheet 9. To implement. FIG. 4 is a perspective view schematically showing an example of the integration process. In FIG. 4, what can be visually recognized through the polyester-type sheet | seat 9 which is transparent or translucent 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 polyester sheet 9. Make it work. Then, the polyester sheet 9 comes into close contact with the wafer 1 due to atmospheric pressure.

  Next, the polyester sheet 9 is heated while sucking the polyester sheet 9 by the suction source 2b. The polyester sheet 9 is heated by, for example, a heat gun 4 disposed above the chuck table 2 as shown in FIG.

  The heat gun 4 includes heating means such as a heating wire and a blowing mechanism such as a fan inside, and can heat and inject air. When a negative pressure from the suction source 2b is applied to the polyester sheet 9, hot air 4a is supplied from the upper surface to the polyester sheet 9 by the heat gun 4, and the polyester sheet 9 is heated to a predetermined temperature, so that the polyester sheet 9 becomes the wafer 1. It is thermocompression bonded to.

  After the polyester-based sheet 9 is thermocompression bonded, 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.

  In addition, when implementing thermocompression bonding, the polyester-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 polyester sheet 9 may be dissolved and the sheet shape may not be maintained. Further, the polyester sheet 9 is preferably heated to a temperature equal to or higher than its softening point. This is because thermocompression bonding cannot be performed properly unless the heating temperature reaches the softening point. In other words, the polyester sheet 9 is preferably heated to a temperature not lower than its softening point and not higher than its melting point.

  Furthermore, some polyester-based sheets 9 may not have a clear softening point. Therefore, when the thermocompression bonding is performed, the polyester 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 polyester sheet 9 is a polyethylene terephthalate sheet, the heating temperature is set to 250 ° C. to 270 ° C. Moreover, when this polyester-type sheet | seat 9 is a polyethylene naphthalate sheet, heating temperature shall be 160 to 180 degreeC.

  Here, heating temperature means the temperature of the polyester-type sheet | seat 9 at the time of implementing an integration process. For example, although a model capable of setting the output temperature is provided for a heat source such as the heat gun 4, the temperature of the polyester sheet 9 is set even when the polyester sheet 9 is heated using the heat source. The output temperature may not be reached. Therefore, in order to heat the polyester sheet 9 to a predetermined temperature, the output temperature of the heat source may be set higher than the melting point of the polyester sheet 9.

  In the processing method of the wafer 1 according to the present embodiment, a frame support process for supporting the polyester sheet 9 with the frame 7 is performed before or after the integration process. FIG. 5A is a perspective view schematically showing the frame supporting step. In the frame support step, the polyester sheet 9 is supported by the frame 7 by sandwiching the outer periphery of the polyester sheet 9 between the first frame 7a and the second frame 7f.

  First, the polyester sheet 9 is placed on the upper surface 7c of the first frame 7a. At this time, the position of the polyester sheet 9 is determined so as to block all the openings 7b of the first frame 7a. Next, the second frame 7f is placed on the polyester sheet 9 with the lower surface 7h facing downward. At this time, the position of the second frame 7f is determined so that the through hole 7i of the second frame 7f is fitted into the pin 7d of the first frame 7a.

  When the first frame 7a and the second frame 7f are overlapped, the magnetic force generated by the plurality of magnets 7e included in the first frame 7a acts and the two frames are attracted to each other. It is sandwiched between both frames. Accordingly, the polyester sheet 9 is supported by the frame 7. At this time, since the pin 7d of the first frame 7a is fitted into the through hole 7i of the second frame 7f, the first frame 7a and the second frame 7f do not shift in the horizontal direction.

  In addition, although the case where a frame support process is implemented after an integration process was demonstrated, the wafer processing method which concerns on this embodiment is not limited to this. For example, the integration step may be performed after the frame support step. In this case, the outer periphery of the polyester sheet 9 is bonded to the first frame 7a and the second frame 7f by heating in the integration step, and the polyester sheet 9 is supported by the frame 7 with a stronger force.

  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 6 includes a cutting unit 8 that cuts a workpiece, and a chuck table (not shown) that holds the workpiece. The cutting unit 8 includes a cutting blade 12 having an annular grindstone part, and a spindle (not shown) that rotates the cutting blade 12 with its distal end passing through a central through hole of the cutting blade 12. The cutting blade 12 includes, for example, an annular base having the through-hole at the center, and an annular grindstone disposed on the outer periphery of the annular base.

  The base end side of the spindle is connected to a spindle motor (not shown) housed in the spindle housing 10, and the cutting blade 12 can be rotated by operating the spindle motor.

  When the workpiece is cut by the cutting blade 12, heat is generated by friction between the cutting blade 12 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 12 and the workpiece while cutting the workpiece. The cutting unit 8 includes, for example, a cutting water supply nozzle 14 that supplies cutting water to the cutting blade 12 or the like on the side of the cutting blade 12.

  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 polyester 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 6. Further, the relative positions of the chuck table and the cutting unit 8 are adjusted so that the cutting blade 12 is disposed above the extended line of the division line 3.

  Next, the cutting blade 12 is rotated by rotating the spindle. Then, the cutting unit 8 is lowered to a predetermined height position, and the chuck table and the cutting unit 8 are relatively moved along a direction parallel to the upper surface of the chuck table. Then, the grindstone portion of the rotating cutting blade 12 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 polyester sheet 9.

  After cutting along one division line 3, the chuck table and the cutting unit 8 are moved in an indexing feed direction perpendicular to the machining feed direction, and the wafer 1 is similarly cut along the other 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 6 may include a cleaning unit (not shown) in the vicinity of the cutting unit 8. The wafer 1 cut by the cutting unit 8 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 polyester sheet 9. When cutting the wafer 1, in order to divide the wafer 1 reliably, the cutting unit 8 is set to a predetermined height so that the height position of the lower end of the cutting blade 12 is lower than the back surface 1b of the wafer 1. Positioned. Therefore, when the wafer 1 is cut, the polyester sheet 9 is also cut, and cutting waste derived from the polyester sheet 9 is generated.

  When an adhesive tape is used for the frame unit 11 instead of the polyester sheet 9, 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 14 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, the polyester sheet 9 not having the glue layer is used instead of the adhesive tape having the glue layer in the frame unit 11. Even if cutting waste derived from the polyester 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 of picking up individual device chips from the polyester sheet 9 is performed. In the pickup process, a pickup device 16 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 16.

  The pickup device 16 includes a cylindrical drum 18 having a diameter larger than the diameter of the wafer 1 and a frame holding unit 20 including a frame support base 22. The frame support base 22 of the frame holding unit 20 includes an opening having a diameter larger than the diameter of the drum 18 and is disposed at the same height as the upper end portion of the drum 18. Enclose from.

  A clamp 24 is disposed on the outer peripheral side of the frame support base 22. When the frame unit 11 is placed on the frame support base 22 and the frame 7 of the frame unit 11 is gripped by the clamp 24, the frame unit 11 is fixed to the frame support base 22.

  The frame support 22 is supported by a plurality of rods 26 extending in the vertical direction, and an air cylinder 28 for moving the rods 26 up and down is disposed at the lower end of each rod 26. The plurality of air cylinders 28 are supported by a disk-shaped base 30. When each air cylinder 28 is operated, the frame support 22 is pulled down with respect to the drum 18.

  Inside the drum 18, a push-up mechanism 32 that pushes up the device chip supported by the polyester sheet 9 from below is disposed. The push-up mechanism 32 has a function of blowing air 32a upward. Further, a collet 34 (see FIG. 8B) capable of sucking and holding the device chip is disposed above the drum 18. The push-up mechanism 32 and the collet 34 are movable in the horizontal direction along the upper surface of the frame support base 22. The collet 34 is connected to the suction source 34a (see FIG. 8B) via the switching unit 34b (see FIG. 8B).

  In the pickup process, first, the air cylinder 28 is operated to adjust the height of the frame support 22 so that the height of the upper end of the drum 18 of the pickup device 16 and the height of the upper surface of the frame support 22 are substantially the same. Adjust. For example, the height position of the upper surface of the frame support 22 may be positioned at a height position lower than the upper end of the drum 18 by the thickness of the first frame 7a. Next, the frame unit 11 carried out from the cutting device 6 is placed on the drum 18 of the pickup device 16.

  Thereafter, the frame 7 of the frame unit 11 is fixed on the frame support 22 by the clamp 24. FIG. 8A is a cross-sectional view schematically showing the frame unit 11 fixed on the frame support base 22. On the wafer 1, cutting marks 3a are formed and divided by the dividing step.

  Next, the air cylinder 28 is operated to pull down the frame support 22 of the frame holding unit 20 with respect to the drum 18. Then, as shown in FIG. 8B, the polyester sheet 9 is expanded in the outer peripheral direction. FIG. 8B is a cross-sectional view schematically showing the pickup process.

  When the polyester sheet 9 is expanded in the outer circumferential direction, the distance between the device chips 1c supported by the polyester 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 32 is moved below the device chip 1c, and the collet 34 is moved above the device chip 1c.

  Thereafter, the device chip 1c is pushed up by operating the push-up mechanism 32 and blowing air 32a from the polyester sheet 9 side. And the switching part 34b is operated and the collet 34 is connected to the suction source 34a. Then, the device chip 1 c is sucked and held by the collet 34 and the device chip 1 c is picked up from the polyester 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 32a is blown onto the device chip from the polyester 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 polyester 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-described embodiment, the case where the polyester sheet 9 is, for example, a polyethylene terephthalate sheet or a polyethylene naphthalate sheet has been described, but one aspect of the present invention is not limited thereto. For example, other materials may be used for the polyester sheet, such as a polytrimethylene terephthalate sheet, a polybutylene terephthalate sheet, or a polybutylene naphthalate.

  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, 7a, 7f Frame 7b, 7g Opening 7c Upper surface 7d Pin 7e Magnet 7h Lower surface 7i Through hole 9 Polyester sheet 11 Frame unit 2 Chuck table 2a Holding surface 2b, 34a Suction source 2c, 34b Switching unit 4 Heat gun 4a Hot air 6 Cutting device 8 Cutting unit 10 Spindle housing 12 Cutting blade 14 Cutting water supply nozzle 16 Pickup device 18 Drum 20 Frame holding unit 22 Frame support 24 Clamp 26 Rod 28 28 Air Cylinder 30 Base 32 Pushing mechanism 32a Air 34 Collet

Claims (5)

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 polyester-based sheet disposing step of disposing a polyester-based sheet on the back surface of the wafer;
An integration step of heating the polyester sheet by applying hot air to the polyester sheet, and integrating the wafer and the polyester sheet;
Before or after the integration step, a first frame having an opening sized to accommodate the wafer and having a plurality of magnets, and a second frame having an opening sized to accommodate the wafer, The polyester sheet is sandwiched between the first frame and the second frame by the magnetic force generated by the magnet, and the outer periphery of the polyester sheet is sandwiched between the first frame and the second frame. A frame support step for supporting the frame;
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 chips individually by blowing air from the polyester sheet side, and picking up the individual device chips from the polyester sheet;
A method for processing a wafer, comprising:   2. The wafer processing method according to claim 1, wherein, in the pick-up step, the polyester sheet is expanded to widen the space between the device chips, and the device chip is pushed up from the polyester sheet side.   2. The wafer processing method according to claim 1, wherein the polyester sheet is a polyethylene terephthalate sheet or a polyethylene naphthalate sheet.   In the integration step, when the polyester sheet is the polyethylene terephthalate sheet, the heating temperature is 250 ° C. to 270 ° C., and when the polyester sheet is the polyethylene naphthalate sheet, the heating temperature is 160 ° C. to The wafer processing method according to claim 3, wherein the wafer processing temperature is 180 ° C.   2. The wafer processing method according to claim 1, wherein the wafer is made of any one of Si, GaN, GaAs, and glass.