JP7139040B2 - Wafer processing method - Google Patents

Description

The present invention relates to a wafer processing method for dividing a wafer, in which a plurality of devices are formed in respective regions of a surface partitioned by dividing lines, into individual devices.

2. Description of the Related Art In the manufacturing process of device chips used in electronic devices such as mobile phones and personal computers, first, a plurality of intersecting dividing lines (streets) are set on the surface of a wafer made of a material such as a semiconductor. Then, devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in the regions partitioned by the planned division lines.

After that, an adhesive tape called a dicing tape, which is attached to an annular frame having an opening so as to close the opening, is attached to the back surface of the wafer, and the wafer, the adhesive tape, and the annular frame are integrated. form a frame unit. Then, by processing and dividing the wafer contained in the frame unit along the planned division lines, individual device chips are formed.

A cutting device, for example, is used to divide the wafer. The cutting device includes a chuck table that holds the 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 penetrating through a central through hole of the cutting blade and rotating the cutting blade.

When cutting a wafer, the frame unit is placed on the chuck table, the wafer is held by the chuck table via adhesive tape, the cutting blade is rotated by rotating the spindle, and the cutting unit is raised to a predetermined height. lower into 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 cutting blade cuts the wafer along the dividing lines. The wafer is then divided.

After that, the frame unit is carried out from the cutting device, the adhesive tape is subjected to treatment such as irradiation with ultraviolet rays to reduce the adhesive strength 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 that can continuously divide a wafer and irradiate an adhesive tape with ultraviolet rays (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

The adhesive tape includes a base layer and a glue layer disposed on the base layer. In the cutting apparatus, 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 in order to reliably divide the wafer. Therefore, the cutting blade that cuts the wafer also cuts the glue layer of the adhesive tape. Therefore, when the wafer is cut, shavings derived from the glue layer are generated together with shavings derived from the wafer.

A cutting fluid is supplied to the wafer and the cutting blade during cutting of the wafer, and the cutting debris generated by cutting is taken into the cutting fluid and spreads over the surface of the wafer. Here, cutting debris originating from the adhesive layer tends to reattach to the surface of the device, and is not easily removed in the subsequent wafer cleaning step or the like. As a result, the adherence of shavings derived from the adhesive layer poses a problem of deterioration in the quality of the device chip.

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

According to one aspect of the present invention, there is provided a wafer processing method for dividing a wafer in which a plurality of devices are formed in respective regions of a front surface partitioned by dividing lines into individual device chips, comprising: A polyester-based sheet disposing step of disposing a polyester-based sheet having no glue layer, an integration step of heating the polyester-based sheet and integrating the wafer and the polyester-based sheet by thermocompression bonding, Before or after the integration step, using a frame composed of an inner frame having an opening large enough to accommodate a wafer and an outer frame having an opening having a diameter corresponding to the outer diameter of the inner frame. a frame supporting step of supporting the polyester-based sheet with the frame by sandwiching the outer periphery of the polyester-based sheet between the outer peripheral wall of the inner frame and the inner peripheral wall of the outer frame; and making the cutting blade rotatable. a dividing step of cutting the wafer along a dividing line using the provided cutting device to divide the wafer into individual device chips; and a picking-up step of picking up the individual device chips from the polyester-based sheet. A method for processing a wafer is provided, comprising:

Preferably, in the integration step, the thermocompression bonding is performed by infrared irradiation.

Preferably, in the pick-up step, the polyester sheet is expanded to widen the distance between the device chips, and the device chips are pushed up from the polyester sheet side.

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

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

Also preferably, the wafer is made of Si, GaN, GaAs, or glass.

In the wafer processing method according to one aspect of the present invention, the frame unit and the wafer are integrated using a polyester-based sheet having no adhesive layer without using an adhesive tape having an adhesive layer in the frame unit. An integration process for integrating the polyester sheet and the wafer is realized by thermocompression bonding.

In a wafer processing method according to an aspect of the present invention, a frame is composed of an inner frame having an opening large enough to accommodate a wafer, and an outer frame having an opening having a diameter corresponding to the outer diameter of the inner frame. is used. Then, in the frame supporting step, the inner frame is inserted into the opening of the outer frame, and at this time, a polyester sheet is sandwiched between the outer peripheral wall of the inner frame and the inner peripheral wall of the outer frame. can support the polyester sheet with a frame.

That is, even if the polyester-based sheet does not have a glue layer, the wafer, the polyester-based sheet, and the frame can be integrated to form a frame unit by performing the integrating step and the frame supporting step. .

After that, the wafer is cut by a cutting blade to divide the wafer into individual device chips, and the device chips are picked up from the polyester-based sheet. Each of the picked-up device chips is mounted on a predetermined mounting target.

When cutting the wafer, the cutting blade also cuts into the polyester-based sheet under the wafer, so cutting waste derived from the polyester-based sheet is generated. However, since the polyester-based sheet does not have a glue layer, even if the shavings are taken into the cutting water and spread over the surface of the wafer, the shavings are relatively difficult to adhere to the wafer. Moreover, even if cutting waste adheres to the wafer, it can be easily removed by the subsequent washing 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. quality deterioration is suppressed.

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

It is a perspective view which shows a wafer typically. FIG. 4 is a perspective view schematically showing how the wafer is positioned on the holding surface of the chuck table; It is a perspective view which shows typically a polyester-type sheet arrangement|positioning process. It is a perspective view which shows an example of an integration process typically. It is a perspective view which shows an example of an integration process typically. It is a perspective view which shows an example of an integration process typically. FIG. 7A is a perspective view schematically showing the frame supporting process, and FIG. 7B is a perspective view schematically showing the formed frame unit. It is a perspective view which shows a division process typically. FIG. 10 is a perspective view schematically showing loading of the frame unit into the pickup device; FIG. 10(A) is a cross-sectional view schematically showing the frame unit fixed on the frame support, and FIG. 10(B) is a cross-sectional view schematically showing the pickup process.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a wafer to be processed by the processing method according to this embodiment will be described. FIG. 1 is a perspective view schematically showing a wafer 1. FIG. The wafer 1 is made of materials such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductors, or materials such as sapphire, glass, or quartz. It is a substantially disc-shaped substrate or the like.

The front surface 1a of the wafer 1 is partitioned by a plurality of dividing lines 3 arranged in a lattice. In addition, devices 5 such as ICs (Integrated Circuits) and LEDs (Light Emitting Diodes) are formed in respective regions partitioned by dividing lines 3 on the front surface 1a of the wafer 1 . In the method for processing the wafer 1 according to the present embodiment, the wafer 1 is cut along the dividing lines 3 to be divided into individual device chips.

A wafer 1 is cut by a cutting device. Before carrying the wafer 1 into the cutting apparatus, the wafer 1, the polyester-based sheet and the frame are integrated to form a frame unit. The wafer 1 is loaded into a cutting device in the state of a frame unit and cut. Each formed device chip is supported by a polyester sheet. After that, the distance between the device chips is widened by expanding the polyester sheet, and the device chips are picked up by a pick-up device.

An annular frame 7 (see FIG. 7A, etc.) is formed of a material such as metal, for example, and corresponds to an inner frame 7c having an opening large enough to accommodate the wafer 1 and an outer diameter of the inner frame 7c. and an outer frame 7a having an opening with a diameter equal to that of the outer frame 7a. The inner frame 7c and the outer frame 7a have substantially the same height.

The polyester-based sheet 9 (see FIG. 3, etc.) is a resin-based sheet having flexibility, and has flat front and back surfaces. 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, such as a polyethylene terephthalate sheet, or , polyethylene naphthalate sheet, etc., which are transparent or translucent to visible light. However, the polyester sheet 9 is not limited to this, and may be opaque.

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

In the method for processing the wafer 1 according to the present embodiment, the polyester sheet 9 is adhered to the back surface 1b side of the wafer 1 by thermocompression bonding, and the outer peripheral portion of the polyester sheet 9 is connected to the outer peripheral wall 7e of the inner frame 7c and the outer frame. A frame unit is formed by sandwiching between the inner peripheral wall 7b of 7a.

Next, each step of the method for processing the wafer 1 according to this embodiment will be described. First, in preparation for integrating the wafer 1 and the polyester-based sheet 9, a polyester-based sheet disposing step is carried out. FIG. 2 is a perspective view schematically showing how the wafer 1 is positioned on the holding surface 2a of the chuck table 2. As shown in FIG. As shown in FIG. 2, the process of arranging the polyester-based sheet is performed on a chuck table 2 having a holding surface 2a on its top.

The chuck table 2 has a porous member with a diameter larger than the outer diameter of the wafer 1 in the upper center. The upper surface of the porous member serves as the holding surface 2a of the chuck table 2. As shown in FIG. As shown in FIG. 3, the chuck table 2 has therein an exhaust path, one end of which communicates with the porous member, and a suction source 2b is arranged on the other end of the exhaust path. The exhaust path is provided with a switching portion 2c for switching between a connected state and a disconnected state. Pressure is applied, and the object to be held is held by suction on the chuck table 2 .

In the process of arranging the polyester sheet, 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 of the wafer 1 faces downward. Next, a polyester sheet 9 is arranged on the back surface 1b of the wafer 1. As shown in FIG. FIG. 3 is a perspective view schematically showing a step of disposing a polyester-based sheet. As shown in FIG. 3, a polyester sheet 9 is placed on the wafer 1 so as to cover the wafer 1 .

In addition, in the polyester-based sheet disposing step, a chuck table 2 having a holding surface 2a with a smaller diameter than the diameter of the polyester-based sheet 9 is used. When applying the negative pressure to the polyester sheet 9 by the chuck table 2 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 will leak through the gap. , the pressure cannot be appropriately applied to the polyester sheet 9 .

In the method for processing the wafer 1 according to the present embodiment, next, the polyester-based sheet 9 is heated, and an integration step is performed in which the wafer 1 and the polyester-based sheet 9 are integrated by thermocompression bonding. FIG. 4 is a perspective view schematically showing an example of the integration process. In FIG. 4, the dashed lines indicate what can be seen through the polyester-based sheet 9, which is transparent or translucent to visible light.

In the integration step, first, the switching portion 2c of the chuck table 2 is operated to be in a communicating state, the suction source 2b is connected to the porous member above the chuck table 2, and the negative pressure from the suction source 2b is applied to the polyester sheet 9. act. Then, the polyester sheet 9 is brought into close contact with the wafer 1 by the atmospheric pressure.

Next, while the polyester sheet 9 is being sucked by the suction source 2b, the polyester sheet 9 is heated to perform thermocompression bonding. For heating the polyester sheet 9, for example, an infrared lamp 4 arranged above the chuck table 2 is used as shown in FIG. The infrared lamp 4 can irradiate infrared rays 4a having a wavelength at least which the material of the polyester-based sheet 9 absorbs.

The infrared lamp 4 is operated to irradiate the polyester sheet 9 with infrared rays 4a to heat the polyester sheet 9. - 特許庁Then, the polyester sheet 9 is thermocompression bonded to the wafer 1 .

Heating of the polyester-based sheet 9 may be performed by other methods. FIG. 5 is a perspective view schematically showing another example of the integration process. In FIG. 5, what can be seen through the polyester-based sheet 9, which is transparent or translucent to visible light, is indicated by dashed lines. The integration process shown in FIG. 5 is performed by a heat gun 6 arranged above the chuck table 2 .

The heat gun 6 includes a heating means such as a heating wire and a blower mechanism such as a fan, and can heat and jet air. While a negative pressure is applied to the polyester sheet 9 by the suction source 2b, hot air 6a is supplied from the upper surface of the polyester sheet 9 by the heat gun 6 to heat the polyester sheet 9 to a predetermined temperature. It is thermocompression bonded to.

Moreover, the heating of the polyester-based sheet 9 may be performed by another method, for example, by pressing the wafer 1 from above with a member heated to a predetermined temperature. FIG. 6 is a perspective view schematically showing another example of the integration process. In FIG. 6, what can be seen through the polyester-based sheet 9, which is transparent or translucent to visible light, is indicated by a dashed line.

In the integration step shown in FIG. 6, for example, a heat roller 8 having a heat source inside is used. Also in the integration step shown in FIG. 6, first, a negative pressure is applied to the polyester-based sheet 9 by the suction source 2b, and the polyester-based sheet 9 is brought into close contact with the wafer 1 by atmospheric pressure.

After that, the heat roller 8 is heated to a predetermined temperature and placed on one end of the holding surface 2 a of the chuck table 2 . Then, the heat roller 8 is rotated to roll the heat roller 8 on the chuck table 2 from the one end to the other end. Then, the polyester sheet 9 is thermocompression bonded to the wafer 1 . At this time, when a force is applied in the direction of pressing down the polyester sheet 9 by the heat roller 8, thermocompression bonding is performed at a pressure higher than the atmospheric pressure. Incidentally, it is preferable to coat the surface of the heat roller 8 with a fluorine resin.

Alternatively, the heat roller 8 may be replaced by an iron-like pressing member having a flat bottom plate and having an internal heat source to carry out thermocompression bonding of the polyester sheet 9 . In this case, the pressing member is heated to a predetermined temperature to form a hot plate, and the polyester sheet 9 held on the chuck table 2 is pressed from above by the pressing member.

When the polyester-based sheet 9 is heated to a temperature near its melting point by any method, the polyester-based sheet 9 is thermocompression bonded to the wafer 1 . After the polyester-based sheet 9 is thermocompressed, the switching part 2c is operated to separate the porous member of the chuck table 2 from the suction source 2b, and the suction by the chuck table 2 is released.

It should be noted that the polyester sheet 9 is preferably heated to a temperature below its melting point when the thermocompression bonding is carried out. This is because if the heating temperature exceeds the melting point, the polyester-based sheet 9 may melt and become unable to maintain the shape of the sheet. Moreover, the polyester-based sheet 9 is preferably heated to a temperature equal to or higher than its softening point. This is because thermocompression bonding cannot be properly performed unless the heating temperature reaches the softening point. That is, the polyester sheet 9 is preferably heated to a temperature above its softening point and below its melting point.

Furthermore, some polyester sheets 9 may not have a definite softening point. Therefore, the polyester sheet 9 is preferably heated to a temperature higher than or equal to 20° C. lower than its melting point and lower than its melting point when thermocompression bonding is performed.

Further, for example, when the polyester sheet 9 is a polyethylene terephthalate sheet, the heating temperature is 250.degree. C. to 270.degree. Further, when the polyester sheet 9 is a polyethylene naphthalate sheet, the heating temperature is set to 160.degree. C. to 180.degree.

Here, the heating temperature refers to the temperature of the polyester-based sheet 9 during the integration process. For example, in the heat sources such as the infrared lamp 4, the heat gun 6, and the heat roller 8, models capable of setting the output temperature have been put into practical use. In some cases, the temperature of 9 does not reach the set output temperature. 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 method for processing the wafer 1 according to the present embodiment, a frame supporting step of supporting the polyester-based sheet 9 with the frame 7 is performed before or after the integrating step. FIG. 7A is a perspective view schematically showing the frame supporting process. In the frame supporting step, the outer periphery of the polyester sheet 9 is sandwiched between the outer peripheral wall 7e of the inner frame 7c of the frame 7 and the inner peripheral wall 7b of the outer frame 7a of the frame 7, thereby supporting the polyester sheet 9 with the frame. Support with 7.

First, the polyester sheet 9 is placed on the inner frame 7c. At this time, the position of the polyester sheet 9 is determined so that the entire area of the upper surface of the inner frame 7 c is covered with the polyester sheet 9 . Next, the outer frame 7a is placed above the polyester sheet 9. As shown in FIG. At this time, the position of the outer frame 7a is determined so that the outer peripheral wall 7e of the inner frame 7c and the inner peripheral wall 7b of the outer frame 7a substantially overlap each other.

After that, the outer frame 7a placed on the polyester sheet 9 is pushed downward to accommodate the inner frame 7c in the opening of the outer frame 7a. At this time, the outer peripheral portion of the polyester sheet 9 is folded by the outer frame 7a and sandwiched between the outer peripheral wall 7e of the inner frame 7c and the inner peripheral wall 7b of the outer frame 7a. Then, as shown in FIG. 7B, a frame unit 11 is formed in which the wafer 1, the polyester sheet 9, and the frame 7 are integrated. In the frame unit 11, a polyester sheet 9 is arranged on the upper surface of the inner frame 7c of the frame 7. As shown in FIG.

Although the case where the frame supporting process is performed after the integration process has been described, the wafer processing method according to this embodiment is not limited to this. For example, the integration process may be performed after the frame support process. In this case, the part sandwiched between the inner frame 7c and the outer frame 7a of the frame 7 of the polyester sheet 9 by heating in the integration process is the outer peripheral wall 7e of the inner frame 7c, the inner peripheral wall 7b of the outer frame 7a, , and the polyester sheet 9 is supported by the frame 7 with a stronger force.

Moreover, the case where the polyester sheet 9 is placed on the inner frame 7c of the frame 7 and the outer frame 7a is placed thereon to carry out the frame supporting step has been described, but the wafer processing method according to the present embodiment Then, the inner frame 7c and the outer frame 7a may be interchanged.

That is, the polyester sheet 9 may be placed on the outer frame 7a, the inner frame 7c may be placed thereon, and the inner frame 7c may be accommodated in the opening of the outer frame 7a by pressing the inner frame 7c from above. In this case, in the formed frame unit, the polyester-based sheet 9 is in contact with the lower surface of the inner frame 7c, and the wafer 1 is placed in the opening surrounded by the inner peripheral wall 7d of the inner frame 7c.

Next, in the method for processing 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 to be divided. A division process is implemented with the cutting apparatus shown, for example in FIG. FIG. 8 is a perspective view schematically showing the dividing step.

The cutting device 10 includes a cutting unit 12 that cuts a workpiece, and a chuck table (not shown) that holds the workpiece. The cutting unit 12 includes a cutting blade 16 having an annular grindstone portion, and a spindle (not shown) whose tip side is passed through a through hole in the center of the cutting blade 16 and rotates the cutting blade 16 . The cutting blade 16 includes, for example, an annular base having the through hole in the center, and an annular grindstone portion provided on the outer periphery of the annular base.

The proximal end of the spindle is connected to a spindle motor (not shown) housed inside the spindle housing 14, and the cutting blade 16 can be rotated by operating the spindle motor.

When the cutting blade 16 cuts the workpiece, heat is generated due to friction between the cutting blade 16 and the workpiece. In addition, when the workpiece is cut, chips are generated from the workpiece. Therefore, in order to remove the heat and chips generated by cutting, cutting water such as pure water is supplied to the cutting blade 16 and the workpiece while the workpiece is being cut. The cutting unit 12 includes, for example, a cutting water supply nozzle 18 that supplies cutting water to the cutting blade 16 or the like on the side of the cutting blade 16 .

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 with the polyester sheet 9 interposed therebetween. Then, the chuck table is rotated to align the dividing line 3 of the wafer 1 with the feed direction of the cutting device 10 . Also, the relative positions of the chuck table and the cutting unit 12 are adjusted so that the cutting blade 16 is disposed above the extension line of the dividing line 3 .

The cutting blade 16 is then rotated by rotating the spindle. Then, the cutting unit 12 is lowered to a predetermined height position, and the chuck table and the cutting unit 12 are relatively moved along the direction parallel to the upper surface of the chuck table. Then, the grindstone portion of the rotating cutting blade 16 comes into contact with the wafer 1 to cut the wafer 1, and cutting marks 3a are formed on the wafer 1 and the polyester-based sheet 9 along the dividing line 3.

After cutting along one of the planned division lines 3, the chuck table and the cutting unit 12 are moved in the index feed direction perpendicular to the processing feed direction, and the wafer 1 is similarly cut along the other planned division lines 3. Carry out cutting. After cutting along all the planned dividing lines 3 along one direction, the chuck table is rotated around the axis perpendicular to the holding surface, and similarly along the planned dividing lines 3 along the other direction. to cut the wafer 1. When the wafer 1 is cut along all the dividing lines 3 of the wafer 1, the dividing step is completed.

The cutting device 10 may include a cleaning unit (not shown) near the cutting unit 12 . The wafer 1 cut by the cutting unit 12 may be transported 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 while the cleaning liquid such as pure water is being supplied to the wafer 1 from the cleaning water supply nozzle, the cleaning water supply nozzle is reciprocated along a path passing above the center of the holding surface. When moved, the front surface 1a side of the wafer 1 can be cleaned.

When performing the dividing step, 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, the cutting unit 12 is set at a predetermined height so that the height position of the lower end of the cutting blade 16 is lower than the back surface 1b of the wafer 1 in order to divide the wafer 1 reliably. It is positioned as Therefore, when the wafer 1 is cut, the polyester-based sheet 9 is also cut, and shavings derived from the polyester-based sheet 9 are generated.

When an adhesive tape is used instead of the polyester-based sheet 9 for the frame unit 11, shavings originating from the glue layer of the adhesive tape are generated. In this case, the cutting waste is taken in by the cutting water jetted from the cutting water supply nozzle 18 and spread over the front surface 1a of the wafer 1 . Cutting debris originating from the glue layer is likely to reattach to the surface of the device 5, and it is not easy to remove it in a cleaning process or the like of the wafer 1 performed after cutting. Adhesion of shavings derived from the adhesive layer causes a problem of deterioration in the quality of the formed device chip.

On the other hand, in the method of processing the wafer 1 according to the present embodiment, the frame unit 11 uses the polyester sheet 9 without a glue layer instead of the adhesive tape with a glue layer. Even if shavings originating from the polyester-based sheet 9 are generated and taken into the cutting water and spread over the surface of the wafer, the shavings are relatively difficult to adhere to the wafer 1 . Moreover, even if cutting waste adheres to the wafer 1, it is easily removed by the subsequent washing process or the like. Therefore, deterioration in quality of the device chip due to the shavings is suppressed.

In the method for processing the wafer 1 according to the present embodiment, next, a pick-up step of picking up the individual device chips from the polyester-based sheet 9 is performed. In the pick-up process, a pick-up device 20 shown in the lower part of FIG. 9 is used. FIG. 9 is a perspective view schematically showing how the frame unit 11 is carried into the pickup device 20. As shown in FIG.

The pickup device 20 includes a cylindrical drum 22 having a diameter larger than that of the wafer 1 and a frame holding unit 24 including a frame support 26 . The frame support base 26 of the frame holding unit 24 has an opening with a diameter larger than the diameter of the drum 22, and is arranged at the same height as the upper end of the drum 22 so that the upper end of the drum 22 faces the outer circumference. surround from Further, the frame support base 26 has an outer diameter corresponding to the diameter of the opening of the inner frame 7c forming the frame 7 of the frame unit 11. As shown in FIG.

Further, the outer peripheral wall of the frame support 26 is provided with, for example, a plurality of suction holes 26a. The frame supporter 26 can apply negative pressure to the inner frame 7c of the frame 7 positioned on the outer peripheral side of the frame supporter 26 through the suction holes 26a. When the frame unit 11 is placed on the frame support base 26 and negative pressure is applied to the inner frame 7c of the frame 7, the frame unit 11 is fixed to the frame support base 26. FIG.

The frame support base 26 is supported by a plurality of rods 28 extending in the vertical direction, and an air cylinder 30 for raising and lowering the rods 28 is provided at the lower end of each rod 28 . A plurality of air cylinders 30 are supported by a disk-shaped base 32 . Actuation of each air cylinder 30 causes the frame support 26 to be lowered relative to the drum 22 .

Inside the drum 22, a push-up mechanism 34 is arranged to push up the device chip supported by the polyester sheet 9 from below. A collet 36 (see FIG. 10B) capable of sucking and holding the device chip is arranged above the drum 22 . The push-up mechanism 34 and collet 36 are horizontally movable along the upper surface of the frame support 26 . Also, the collet 36 is connected to a suction source 36a (see FIG. 10B) via a switching portion 36b (see FIG. 10B).

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 22 of the pickup device 20 and the height of the upper surface of the frame support 26 match. do. Next, the frame unit 11 carried out from the cutting device 10 is placed on the drum 22 of the pickup device 20 . At this time, the frame support 26 is inserted into the opening of the inner frame 7c of the frame 7, and the inner peripheral wall 7d of the inner frame 7c faces the outer peripheral wall of the frame support 26. As shown in FIG.

Thereafter, negative pressure is applied to the inner frame 7c of the frame 7 through the suction holes 26a of the frame support 26 to fix the frame 7 of the frame unit 11 on the frame support 26. As shown in FIG. FIG. 10A is a cross-sectional view schematically showing the frame unit 11 fixed on the frame support base 26. FIG. The wafer 1 is divided by forming cut marks 3a by the dividing step.

Next, the air cylinder 30 is operated to pull down the frame support 26 of the frame holding unit 24 with respect to the drum 22 . Then, as shown in FIG. 10(B), the polyester sheet 9 is expanded in the outer peripheral direction. FIG. 10B is a cross-sectional view schematically showing the pick-up process.

When the polyester-based sheet 9 is expanded in the outer peripheral direction, the intervals between the device chips 1c supported by the polyester-based sheet 9 are widened. As a result, the device chips 1c are less likely to come into contact with each other, making it easier to pick up the individual Debye chips 1c. 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 push-up mechanism 34 is operated to push up the device chip 1c from the polyester sheet 9 side. Then, the switching portion 36b is operated to connect the collet 36 to the suction source 36a. Then, the device chip 1c is held by suction by the collet 36, and the device chip 1c is picked up from the polyester sheet 9. As shown in FIG. The individual device chips 1c picked up are then mounted on a predetermined wiring board or the like for use.

As described above, according to the wafer processing method according to 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 originating from the glue layer of the adhesive tape is not generated, and the cutting waste does not adhere to the device chips 1c. Therefore, the quality of the device chip 1c is not degraded.

It should be noted that the present invention is not limited to the description of the above embodiments, and can be implemented with various modifications. For example, in the above embodiment, the case where the polyester-based 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 to this. For example, other materials may be used for the polyester-based sheet, such as a polytrimethylene terephthalate sheet, a polybutylene terephthalate sheet, a polybutylene naphthalate, or the like.

In addition, the structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

REFERENCE SIGNS LIST 1 wafer 1a front surface 1b back surface 3 dividing line 3a cutting mark 5 device 7 frame 7a outer frame 7b, 7d inner peripheral wall 7c inner frame 7e outer peripheral wall 9 polyester sheet 11 frame unit 2 chuck table 2a holding surface 2b, 36a suction source 2c , 36b switching portion 4 infrared lamp 4a infrared ray 6 heat gun 6a hot air 8 heat roller 10 cutting device 12 cutting unit 14 spindle housing 16 cutting blade 18 cutting water supply nozzle 20 pickup device 22 drum 24 frame holding unit 26 frame support base 26a suction hole 28 Rod 30 Air cylinder 32 Base 34 Thrusting mechanism 36 Collet

Claims (6)

A wafer processing method for dividing a wafer in which a plurality of devices are formed in respective regions of a surface partitioned by dividing lines into individual device chips,
A polyester-based sheet disposing step of disposing a polyester-based sheet having no adhesive layer on the back surface of the wafer;
an integration step of heating the polyester-based sheet and integrating the wafer and the polyester-based sheet by thermocompression bonding;
Before or after the integration step, using a frame composed of an inner frame having an opening large enough to accommodate a wafer and an outer frame having an opening having a diameter corresponding to the outer diameter of the inner frame. a frame supporting step of supporting the polyester-based sheet with the frame by sandwiching the outer periphery of the polyester-based sheet between the outer peripheral wall of the inner frame and the inner peripheral wall of the outer frame;
a dividing step of cutting the wafer along lines to be divided using a cutting device having a rotatable cutting blade to divide the wafer into individual device chips;
a pick-up step of picking up individual device chips from the polyester-based sheet;
A wafer processing method comprising: 2. The method of processing a wafer according to claim 1, wherein said thermocompression bonding is performed by irradiation of infrared rays in said integrating step. 2. The method of processing a wafer according to claim 1, wherein in said pick-up step, said polyester sheet is expanded to widen the space between the device chips, and said device chips are pushed up from said polyester sheet side. 2. The wafer processing method according to claim 1, wherein said polyester sheet is either a polyethylene terephthalate sheet or a polyethylene naphthalate sheet. In the integration step, the heating temperature is 250° C. to 270° C. when the polyester sheet is the polyethylene terephthalate sheet, and the heating temperature is 160° C. to 160° C. when the polyester sheet is the polyethylene naphthalate sheet. 5. The method of processing a wafer according to claim 4, wherein the temperature is 180.degree. 2. The method of processing a wafer according to claim 1, wherein said wafer is made of any one of Si, GaN, GaAs and glass.

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