JP5871719B2 - Work dividing apparatus and work dividing method - Google Patents

Description

  The present invention relates to a workpiece dividing apparatus and a workpiece dividing method, and in particular, a dicing tape is mounted on a semiconductor wafer mounted on a ring-shaped frame via a dicing tape and diced and grooved into individual chips after dicing. The present invention relates to a workpiece dividing apparatus and a workpiece dividing method for expanding and dividing into individual chips.

  Conventionally, in the manufacture of semiconductor chips, for example, a semiconductor wafer on which a line to be cut is formed in advance by laser irradiation or the like is attached with a film adhesive for die bonding called DAF (Die Attach Film Die attach film). In a work attached to a frame via a dicing tape (adhesive tape, adhesive sheet), the dicing tape is expanded (expanded) to divide the semiconductor wafer and DAF into individual chips.

  FIG. 28 shows the work. FIG. 28A is a perspective view, and FIG. 28B is a cross-sectional view. As shown in the figure, a semiconductor wafer W has a dicing tape S having a thickness of about 100 μm with an adhesive layer formed on one side and is attached to the back side via DAF (D). Then, the dicing tape S is mounted on a rigid ring-shaped frame F, and in the work dividing device, the semiconductor wafer W is placed on the chuck stage, the dicing tape S is expanded, and is divided into individual chips (divided). )

  Here, DAF is highly viscous near room temperature. As described above, in order to expand the tape with DAF and separate the semiconductor wafer into chips, the DAF is cooled and made brittle. Need to be extended. As typical cooling methods, a low-temperature chuck table method and an atmosphere cooling method are known.

  On the other hand, it is necessary to re-tension the loosened tape after expansion for processing in a process after the tape is expanded and separated into chips. As a typical tension method, there are a method in which a tape expansion ring is crimped on a frame and a method in which the tape is heated with a hot air heater or the like. Of these, the method using a warm air heater is cheaper in running cost, but the warm air diffuses, so it is mounted in a unit that cools and expands the tape, and cooling / expansion and heating / tension are combined into one unit. It was difficult to do in units.

  For example, as a workpiece dividing device, a frame of a workpiece-attached frame that is a frame in which a workpiece on which a division planned line has been formed in advance is supported via a dicing tape is held, and the frame and the workpiece are orthogonal to the workpiece surface The dicing tape is expanded by moving the dicing tape apart, the dividing means for dividing the work along the planned dividing line, the heating means for heating and removing the slack of the dicing tape caused by the expansion, and the frame with the work are rotated. However, there has been proposed a workpiece dividing device including a cleaning unit that cleans a workpiece by supplying a cleaning liquid to the workpiece and a unit that irradiates ultraviolet rays onto a dicing tape of the workpiece (see, for example, Patent Document 1).

JP 2010-206136 A

  However, since the cooling / expansion unit and the heat-shrinking unit are separate units in the device described in Patent Document 1, the workpiece is transported between these units with the tape loosened. In such a state where the tape is slackened, since the tape shape droops greatly and becomes indefinite, the upper surfaces of the chips separated on the tape may contact each other or receive excessive bending stress. is there. Therefore, there is a problem that the chip is damaged, the quality is deteriorated, and the yield is reduced.

  In addition, when the atmosphere is overheated with a heater or the like when tensioning the loosened tape, the previously cooled and embrittled tape is also warmed, resulting in excessive viscosity. That is, after that, when the chip is peeled from the dicing tape, the chip cannot be peeled cleanly from the dicing tape due to the influence of the DAF having an excessive adhesive force. In some cases, DAFs may stick to each other, resulting in poor inter-chip separation.

  The present invention has been made in view of such problems, and by carrying out the holding of the expanded state by cooling and expansion of the workpiece and thermal contraction in the same unit, it is possible to eliminate the conveyance of the workpiece between the units and dicing. An object of the present invention is to provide a workpiece dividing device and a workpiece dividing method which prevent deterioration of quality due to contact between chips due to tape slack, and prevent excessive adhesion to a dicing tape when the DAF is heated. To do.

In order to achieve the above object, a workpiece dividing apparatus according to the present invention divides a workpiece affixed to a dicing tape through a die attach film into individual chips along a predetermined division line. A workpiece holding position for holding the workpiece, and at the same position for holding the workpiece, a workpiece made of a semiconductor wafer having a dividing line, and a dividing line of the workpiece attached to the die attach film. the region of the work, including the selective cooling means for selectively and locally cooling the die attach film by only by that cooled heat transfer Ru contacting the frozen chuck table to the dicing tape, after the cooling, the Expand the dicing tape to divide the workpiece and the die attach film And a heating means for heating a portion of the dicing tape other than the area where the work is pasted via the die attach film to eliminate loosening due to the expanding of the dicing tape. It is characterized by that.

According to the present invention, the selective cooling means for selectively cooling the area of the die attach film to which the work is affixed and the selective heating means for selectively heating a portion other than the area to which the work of the dicing tape is affixed. Therefore, the cooling and expansion of the workpiece and the holding of the expanded state can be performed in the same unit, the workpiece conveyance between the units can be eliminated, and the deterioration of the chip quality due to the slack of the dicing tape can be prevented.
Further, since the selective cooling means is a freezing chuck table, only the region of the die attach film to which the workpiece is attached can be selectively cooled.

  In one embodiment, the selective cooling unit is preferably a cooling unit that cools the workpiece in contact with the dicing tape attached via the die attach film.

  According to this, only the area | region of the die attach film to which the workpiece | work was stuck can be selectively cooled.

  Moreover, as one embodiment, it is preferable that the workpiece dividing means is a push-up ring that pushes and expands the outer peripheral portion of the cooled workpiece relatively from the outer peripheral support portion of the dicing tape.

  According to this, a work can be divided at a time with a simple mechanism.

  Further, as one embodiment, the apparatus further comprises a wafer cover having a bottomed cylindrical shape so as to cover the expanded workpiece region and arranged so as to be able to be raised and lowered, and covering the workpiece when lowered. The means is preferably arranged to be movable up and down around the wafer cover.

  According to this, even if the thrust ring is lowered, the chip interval is maintained, the area of the semiconductor wafer can be shielded from the heat of the selective heating means by the wafer cover, and the die attach film is prevented from melting, It is possible to prevent the gap between the chips from being lost.

  In one embodiment, the workpiece dividing means is a push-up ring that pushes and expands the outer peripheral portion of the cooled workpiece relatively from the outer peripheral support portion of the dicing tape, and the wafer cover includes: When the workpiece is lowered to cover the workpiece, it is preferable that the tip surface of the side portion of the wafer cover is abutted with the tip surface of the expanding push-up ring to seal the workpiece inside the wafer cover.

  Thereby, the area | region of a semiconductor wafer can be shielded completely thermally.

In order to achieve the above object, the work dividing method of the present invention is a work dividing method in which a work affixed to a dicing tape via a die attach film is divided into individual chips along a pre-scheduled dividing line. In the dividing method, the work holding position for holding the work is provided, and the work area including the planned dividing line of the work affixed to the die attach film at the same position for holding the work is defined as the dicing tape. and selective cooling step of selectively and locally cooling the die attach film by that the cooling only the freezer chuck table heat transfer Ru is contacted, after the cooling, the workpiece and said by expanding the dicing tape A workpiece dividing step of dividing the die attach film, and the dicing tape Over click is heated portions other than the region which is attached via the die attach film, characterized in that it comprises a heating step to eliminate slack by said expanding of said dicing tape.

According to the present invention, it is possible to selectively cool a region of a die attach film to which a workpiece is attached and selectively heat a slack generated in a portion other than the region to which the workpiece is attached via a die attach film. In addition, by performing workpiece cooling / expansion and thermal contraction in the same unit, it is possible to eliminate the conveyance of the workpiece between the units, and to prevent deterioration of the chip quality due to the slack of the dicing tape.
Further, in the selective cooling step, since the refrigeration chuck table comes into contact with the dicing tape and cools, only the region of the die attach film to which the workpiece is attached can be selectively cooled.

  In one embodiment, in the workpiece dividing step, it is preferable that the outer peripheral portion of the cooled workpiece is expanded by being pushed up relatively from the outer peripheral support portion of the dicing tape with a push-up ring.

  According to this, a work can be divided at a time with a simple mechanism.

  Further, as one embodiment, the apparatus further comprises a wafer cover having a bottomed cylindrical shape so as to cover the expanded workpiece region and arranged to be movable up and down, and the cylinder when the wafer cover is lowered A tip end surface of the shape is abutted with a tip end surface of the expanding push-up ring, and includes a workpiece covering step for sealing the workpiece inside the wafer cover, and the heating step covers the workpiece It is preferable to heat the periphery of the wafer cover.

  According to this, the area of the die attach film to which the work is affixed is selectively cooled, and the expanded work is covered with the wafer cover to be thermally shielded, and the slack portion of the dicing tape is selectively heated. By doing so, the cooling / expansion and thermal contraction of the workpiece can be performed in the same unit, the conveyance of the workpiece between the units can be eliminated, and the deterioration of the chip quality due to the slack of the dicing tape can be prevented.

  Moreover, as one embodiment, it is preferable that the selective heating step selectively heats a portion other than a region where the work of the dicing tape is pasted through the die attach film by radiation of light.

  According to this, the part loosened by the expansion of the dicing tape can be selectively heated.

  As described above, according to the present invention, the region of the die attach film of the fixed workpiece is selectively cooled, and the slack portion generated in the portion where the expanded state of the dicing tape is not maintained is selectively heated. By doing so, the expanded state of the dicing tape can be maintained even when the expanded state is released, and the expanded state can be maintained in the same unit by cooling / expanding the workpiece and heat shrinking. It is possible to eliminate work conveyance and prevent deterioration of chip quality due to slack of the dicing tape.

It is principal part sectional drawing which shows 1st Embodiment of the workpiece | work division | segmentation apparatus which concerns on this invention. It is a flowchart which shows operation | movement of the workpiece | work division apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the state which the workpiece | work division | segmentation apparatus of 1st Embodiment is expanding. It is sectional drawing which shows the state which inserted the sub ring in the dicing tape. It is sectional drawing which shows the state holding the expansion state of the dicing tape with a sub ring. It is principal part sectional drawing which shows 2nd Embodiment of the workpiece | work division | segmentation apparatus which concerns on this invention. It is an enlarged view of the thermo label affixed on the workpiece | work. It is an enlarged view of the thermo label after the process. It is a flowchart which shows operation | movement of the workpiece | work division apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the state which the workpiece | work division | segmentation apparatus of 2nd Embodiment is expanding. It is sectional drawing which shows the state which lowered | hung the wafer cover. It is sectional drawing which shows the state which fell, holding the dicing tape with the wafer cover and the thrust ring. It is sectional drawing which shows the state which is heating the slack part of the dicing tape with the optical heating apparatus. It is a top view which shows an example of the positional relationship of a light heating apparatus and a dicing tape. It is a top view which shows a mode that a light heating apparatus is rotationally scanned. It is a top view which shows the example provided with eight light heating apparatuses. It is a top view which shows a mode that the eight selective heating apparatuses of FIG. 16 are rotationally scanned. It is explanatory drawing which shows the measurement position of the dicing tape heated with the optical heating apparatus. It is explanatory drawing which shows the measurement direction in each measurement position of FIG. It is explanatory drawing which shows a measurement result. It is explanatory drawing which shows the measurement result of a comparative example. It is a thermotracer screen which shows a mode that the outer peripheral part of the dicing tape was heated. It is the thermotracer screen which shows a mode that the dicing tape outer peripheral part was similarly heated. It is sectional drawing which shows the state after heat-hardening a dicing tape. It is a top view which shows the workpiece | work after the heat processing by which the chip | tip space | interval was maintained. It is sectional drawing which shows the state by which a chip | tip space | interval is not maintained when not applying this invention. It is a flowchart which shows operation | movement of the workpiece | work division | segmentation apparatus as a modification of 2nd Embodiment. (A) which shows a workpiece | work is a perspective view, (b) is sectional drawing.

  Hereinafter, a work dividing apparatus and a work dividing method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of an essential part showing a first embodiment of a workpiece dividing apparatus according to the present invention.

  As shown in FIG. 1, the workpiece dividing device 1 includes a refrigeration chuck table 10 and a push-up ring 12. On the freezing chuck table 10, a workpiece 2 in which a semiconductor wafer W is mounted on a frame F via a dicing tape S as shown in FIG. A dicing tape S is attached to the back surface of the semiconductor wafer W via a DAF (Die Attach Film Die attach film) D (hereinafter referred to as DAF (D)). Here, for example, the semiconductor wafer W has a thickness of about 50 μm, and the DAF (D) and the dicing tape S each have a thickness of about several μm to 100 μm.

  In the present embodiment, a heat shrink experiment was performed using the following tape. In other words, the dicing tape used was a UC-353EP-110 manufactured by Furukawa Electric or D-675 manufactured by Lintec as a PO (polyolefin) tape, and a UE manufactured by Nitto Denko as a PVC (polyvinyl chloride) tape. -110B, D-175 manufactured by Lintec, and UV-type DAF tapes (base material is PO-based) include FH series (for example, FH-9011) manufactured by Hitachi Chemical.

  Moreover, as a pressure-sensitive DAF tape (a base material is PO type), HR series (for example, HR-9004) manufactured by Hitachi Chemical Co., Ltd. may be mentioned. It has been confirmed that any of these tapes can be thermally shrunk, but details of the experimental results will be described later.

  In addition, the thermal conductivity of these tapes is 0.3 to 0.5 W / m · K for PO-based tapes that include polyethylene as a representative example, and 0.1 to 0.3 W for PVC-based tapes. / M · K. Further, although Si differs depending on the doping amount and crystal orientation, its thermal conductivity is 130 to 170 W / m · K. The dry air has a thermal conductivity of 0.02 to 0.03 W / m · K.

  As an image of the ease of heat transfer, if the air is 1, the tape is 10 and the silicon is 10,000.

For example, on a 0.1 mm thick PO-based tape (assuming a thermal conductivity of 0.4 W / m · K) and a 0.02 mm thick DAF (assuming a thermal conductivity of 1 W / m · K) When 0.1 mm thick silicon (having a thermal conductivity of 160 W / m · K) is pasted, the PO tape has a thermal resistance value of 0.0001 m / 0.4 W / m · K = 0.00025 m. ² · K / W, and the thermal resistance value of the DAF is 0.00002 m / 1 W / m · K = 0.00002 m ² · K / W. The thermal resistance value of silicon is 0.0001 m / 160 W / m · K = 0.0000000625 m ² · K / W.

Since these are now connected in series, the thermal resistance value from the back surface of the tape to the top surface of the silicon is the sum of the above, and is 0.000270625 m ² · K / W.

By the way, the thermal resistance value R of the dicing tape + DAF from the freezing chuck table to the portion 1 mm outside is obtained as follows. That is, the thermal resistance value of the PO-based tape is 0.001 m / 0.4 W / m · K = 0.0025 m ² · K / W, and the thermal resistance value of the DAF is 0.001 m / 1 W / m · K = 0. .001m ² · K / W, and since these are connected in parallel, they can be obtained from the following equation regarding parallel connection of resistors.

1 / R = 1 / 0.0025 + 1 / 0.001 = 400 + 1000 = 1400
Accordingly, R = 1/1400 = 0.00071 m ² · K / W.

  Therefore, with respect to the thermal resistance value from the back surface of the dicing tape to the upper surface of the silicon, the thermal resistance value from the freezing chuck table to the portion of the dicing tape 1 mm outside is 0.00071 ÷ 0.000270625 = 2.62355. Approximately 2.6 times.

  Therefore, it can be seen that the dicing tape on the outer periphery of the freezing chuck table is less likely to be cooled by the freezing chuck table than the silicon upper surface. Furthermore, the influence of external air is greater in a dicing tape having an air layer in a direction perpendicular to the heat transfer direction. From the above, it can be seen that the temperature of the outer periphery of the freezing chuck table is less likely to be lower than the upper surface of the silicon.

  The freezing chuck table 10 holds the work 2 by vacuum suction, brings the work 2 into contact with the freezing chuck table 10, and DAF (D) is 0 ° C. or less, for example −5 ° C., by heat transfer through the contacted part. It cools to about -10 degreeC. Note that heat transfer in the same substance is referred to as heat conduction, and heat transfer is performed when different substances come into contact with each other.

  As a method of freezing, there is a method of freezing by supplying a refrigerant into the chuck, but a method of freezing the chuck surface using the Peltier effect may be used. The freezing chuck table vacuum-sucks the back surface of the wafer via a dicing tape and DAF. The characteristic is that, as can be seen from the above description, the adsorption region is cooled immediately by heat transfer, while the portions other than the adsorption region need not be cooled much. This is because, unlike the case where the atmosphere is simply cooled by convection or the like, the cooling by heat transfer can cool only the portion to be locally cooled.

  Thus, it can be seen that only the wafer division region can be selectively cooled by the refrigeration chuck table. The reason will be described in more detail below.

  As described above, the thickness of the DAF and the adhesive tape is at most about 100 μm. Therefore, the distance from the surface of the freezing chuck table is at most 0.2 mm within the distance to the DAF, the adhesive tape, and the wafer. On the other hand, since the difference in diameter from the outer periphery of the freezing chuck table to the outer periphery of the DAF is 12 mm, there is about 6 mm on one side.

  Here, regarding the phenomenon of heat transfer, the amount of heat is conducted and transferred in proportion to the temperature gradient and the cross-sectional area.

  The total amount ΔQ of heat passing through a cross section in a minute section SΔx surrounded by a thickness Δx and an area S is expressed as follows: thermal conductivity λ, contact area S, temperature u, temperature gradient Δu / Δx, minute time Δt It can be expressed by a formula.

ΔQ = λS (Δu / Δx) Δt (1)
Note that heat transfer conducted between different materials is basically the same as heat conduction conducted in the same kind of material, and only the heat transfer coefficient is applied instead of the heat conductivity.

  Therefore, it is assumed that the freezing chuck table is cooled to, for example, −5 ° C. Then, in the wafer area, the thickness Δx of the DAF and the adhesive tape is 0.2 mm at most, whereas the cross-sectional area S through which heat is transferred corresponds to the entire wafer area. Therefore, the amount of heat transferred by heat transfer is very large, and even if the heat transfer coefficient and heat conductivity of the DAF and the adhesive tape are somewhat low, the DAF in the wafer region is immediately cooled by heat transfer.

  On the other hand, the outer diameter portion of the DAF is 6 mm away from the outer diameter of the freezing chuck in the previous case. That is, Δx corresponding to the distance through which heat is conducted is 6 mm. Further, since the dicing tape to which the DAF is attached is formed of a resin such as polyethylene, the thermal conductivity λ is also low. Furthermore, since the polyethylene has a very small thickness of 100 μm, that is, the cross-sectional area S through which heat is transmitted is very small. As a result, the thermal conductivity transmitted through the dicing tape or DAF is extremely low as compared with the heat transfer to the wafer.

  Therefore, the portion where the refrigeration chuck does not contact, the outer peripheral portion of the DAF which is substantially separated by the thickness of the dicing tape is not affected by being cooled by the heat conduction from the refrigeration chuck. In addition, since most of the area of the dicing tape away from the freezing chuck is exposed to the surrounding atmosphere, it is governed not by the temperature of the freezing chuck but by the temperature of the surrounding atmosphere other than the freezing chuck. . Therefore, for example, when the surrounding atmosphere is kept at room temperature, the temperature of the surrounding atmosphere is almost the region other than the region where the freezing chuck is in contact. That is, it is possible to form a boundary region of a substantial temperature in the freezing area of the freezing chuck.

  The formation of the boundary region as described above means that the thickness of the DAF tape or the thickness of the dicing tape is a distance from the wafer region (strictly, the region that divides both the wafer and the DAF) to the DAF that protrudes from the outer peripheral portion. This is because they are smaller (thin).

  Thus, it is possible to limit the cooling area by heat transfer and efficiently cool only a predetermined area (area to be divided).

  Therefore, since DAF tape is conventionally a stretchable material, the DAF outer diameter is about 10 mm from the wafer diameter, at least the DAF outer diameter, in order to ensure that the DAF tape is securely attached to the backside of the wafer. 2 mm or more (1 mm or more on one side) had to be larger than the wafer diameter.

  In this state, when the entire area of the DAF is lowered, the DAF in the outer peripheral portion where the wafer is not present becomes brittle when the temperature is lowered. As a result, the DAF is an adhesive tape due to a difference in stretchability with the dicing tape existing under the DAF. I was turning up. A part of the DAF turned up is separated and falls on the wafer, and there is a problem that the DAF adheres to the wafer as a foreign matter.

  However, even with DAF attached, considering heat transfer, use a sufficiently thin DAF and dicing tape, use a freezing chuck, chuck the wafer area in vacuum, and chucked wafer By efficiently locally cooling only the region by the heat transfer phenomenon, the DAF that protrudes from the outer periphery of the wafer is not cooled. Therefore, the problem that the outer peripheral DAF becomes brittle by cooling, turns up and falls onto the wafer does not occur.

  On the other hand, since the DAF splitting property is improved in the cooled portion, by pulling the dicing tape, the wafer is cleaved and at the same time the DAF can be cut cleanly.

  The size of the freezing chuck table is almost the same size as the wafer area. For example, if the wafer is 8 inches in size (diameter 200 mm), the freezing chuck table should also have good DAF separation on the back side of the wafer. Good.

  Since the expandable dicing tape that holds the wafer needs to be expanded, it naturally becomes an area larger than the wafer. For example, when the wafer is 200 mm in size, the expanding dicing tape is attached to a frame having a size of about 300 mm, and the wafer is inside. There is also between 25 mm and 40 mm or more between the wafer and the frame.

  DAF is stuck between the wafer and the dicing tape. DAF is almost the same diameter as the wafer, but is substantially larger than the wafer. This is because DAF is a stretchable material, and if the size is exactly the same, the wafer may be attached to the DAF with a slight deviation. Even if there is such a slight deviation, in order to always place and attach the wafer on the DAF, the DAF may be slightly larger than the wafer in consideration of the deviation, that is, the outer shape may be increased by about 1 cm. preferable. However, the present invention is not necessarily limited to this, and in an extreme case, the DAF may be the full size of the frame F like the dicing tape.

  The push-up ring 12 is a ring that is arranged so as to surround the refrigeration chuck table 10 and that can be moved up and down by the ring lifting mechanism 16. This ring may be provided with a roller (roller) for reducing the frictional force. In FIG. 1, the push-up ring 12 is located at the lowered position (standby position).

  This push-up ring is preferably formed of a metal having good thermal conductivity such as aluminum. The push-up ring is in contact with the entire circumference of the dicing tape.

  Thus, by making it the structure which contacts a dicing tape, the ring for thrusting has the following functions.

  That is, the region where the DAF is pasted needs to be kept in a cooled state in order to divide the DAF together with the wafer. On the other hand, when looseness occurs after expanding, the looseness must be eliminated. This is because if the chips are transported with the slack remaining, the divided chips collide with each other and damage the chips. In order to eliminate this slack, a heat shrinkable tape having a function of shrinking when heated is used as a dicing tape. As a heat-shrinkable tape used for such a dicing tape, a semiconductor protective sheet (tape) disclosed in JP-A-9-17756 may be used.

  In this case, in the case of expanding and dividing in this case, it is necessary to ensure that the wafer area is frozen to improve the dividing property of the DAF tape, and the outside of the wafer area is loosened. In order to eliminate this, it is necessary to heat and dilate the dicing tape.

  That is, the push-up ring has a function of separating the thermal environment in these two regions.

  The wafer area is cooled by a freezing chuck table. In the cooled state, the inflow of heat from the external heating area is blocked by the push-up ring. In addition, since the dicing tape is made of a polymer and has a lower thermal conductivity than a metal or the like, heat is not easily transmitted to the wafer area existing on the inner peripheral portion of the push-up ring.

  From the above, the thermal environment can be completely isolated in a region by the push-up ring. In other words, the inside of the push-up ring, and particularly the wafer area, is locally cooled to maintain a state in which the DAF division is improved. On the other hand, the outside of the push-up ring can be heated to contract the dicing tape to remove the slack of the outer peripheral portion of the dicing tape caused by the expansion, thereby creating a tense situation.

  In the semiconductor wafer W, as shown in FIG. 28, lines to be divided are formed in a lattice shape in advance by laser irradiation or the like. As will be described in detail later, the push-up ring 12 rises to push up the dicing tape S from below and expand the dicing tape S. By extending the dicing tape S in this way, the division line is divided, and the semiconductor wafer W is divided into individual chips T together with DAF (D).

  By the way, as described above, the DAF (D) is cooled by the freezing chuck table 10 because the DAF (D) has a high viscosity at room temperature, and even if the dicing tape S is pushed up from the lower side by the push-up ring 12, This is because DAF (D) extends with the dicing tape S and is not divided. That is, DAF (D) is cooled and embrittled, so that it can be easily divided.

  As shown in FIG. 1, the work 2 is configured such that the frame F is fixed by the frame fixing mechanism 18 at a position where the back surface of the dicing tape S just contacts the upper surface of the freezing chuck table 10. Yes. A sub-ring 14 is provided on the outer peripheral side of the push-up ring 12. As will be described in detail later, the sub-ring 14 is for maintaining the expanded state of the expanded dicing tape S and maintaining the interval between the divided chips T.

  The operation of dividing the semiconductor wafer W of the workpiece 2 by the workpiece dividing apparatus 1 into individual chips T by the workpiece dividing apparatus 1 will be described below along the flowchart of FIG.

  First, in step S100 of FIG. 2, the frame F of the work 2 having the dicing tape S bonded to the back surface of the semiconductor wafer W via the DAF (D) is fixed by the frame fixing mechanism 18 as shown in FIG. And it arrange | positions so that the area | region where the semiconductor wafer W exists may be located on the freezing chuck table 10. FIG.

  Next, in step S <b> 110 of FIG. 2, the freezing chuck table 10 adsorbs the back surface of the work 2 by vacuum suction so as to contact the surface of the freezing chuck table 10 with certainty. Since the freezing chuck table 10 is in a low temperature state, the workpiece 2 is cooled by heat transfer by this contact. In particular, DAF (D) is cooled to about −5 ° C. to −10 ° C., so that DAF (D) becomes brittle and easily cracks when force is applied. The freezing chuck table 10 performs vacuum suction for a predetermined time, and in particular, cools the workpiece 2 until DAF (D) reaches a predetermined temperature. These controls are performed by a control means (not shown).

  Next, in step S120 of FIG. 2, as shown in FIG. 3, the semiconductor wafer W is divided into pieces together with DAF (D) by expanding.

  That is, as shown in FIG. 3, the freezing chuck table 10 stops the vacuum suction, releases the suction of the work 2, and raises the push-up ring 12 and the sub-ring 14 by the ring lifting / lowering mechanism 16. The push-up ring 12 is raised, for example, at 400 mm / sec and pushed upward by 15 mm. At this time, the sub ring 14 is stopped at a position where it does not rise above the frame F.

  As shown in FIG. 2, the dicing tape S is pushed up from below by the rising of the push-up ring 12, and is expanded (expanded) radially from the center of the semiconductor wafer W within the surface of the dicing tape S. When the dicing tape S is expanded, the semiconductor wafer W is divided along the planned dividing line, and a gap of several μm to 100 μm is formed between the individual chips T. At this time, since the DAF (D) is cooled and becomes brittle, the DAF (D) is also divided along the planned dividing line together with the semiconductor wafer W. As a result, the semiconductor wafer W is divided into individual chips T each having a DAF (D) on the back surface.

  When the dicing tape S is released from the expansion by the push-up ring 12, the dicing tape S returns to its original state due to its elasticity, and there is no gap between the chips T. Therefore, at least in the region where the chips T are present, the dicing tape S is removed. The expanded state must be maintained.

  Therefore, next, in step S130 of FIG. 2, as shown in FIG. 4, the sub-ring 14 is raised by the ring lifting mechanism 16 to a position where it can be inserted into the expanded dicing tape S on the frame F. Insert into the expanded part of the dicing tape S. At this time, the sub ring 14 is raised at a low speed so that the dicing tape S is not broken by the rising sub ring 14.

  Next, in step S140 of FIG. 2, as shown in FIG. 5, the thrust ring 12 is lowered leaving only the sub-ring 14 at a position above the frame F and moved to the lowered position (standby position). . At this time, since the sub-ring 14 remains at the position on the frame F, the expanded state of the dicing tape S is maintained.

  As a result, the expanded state of the dicing tape S is maintained, so that the gaps between the chips T are maintained wide, and the DAF (D) does not adhere again. Therefore, the work 2 is not transported in a state where the dicing tape S is loosened, and the subsequent processing becomes easy.

  As described above, by dividing the work 2 by the method described with reference to the flowchart of FIG. 2, the work is divided (individed into pieces) and the extended state is maintained to maintain the gaps between the divided chips. This can be performed in one unit, and the tact time for manufacturing the product can be increased.

  However, the method of holding the expanded state of the dicing tape S using the sub-ring 14 has a problem that the dicing tape S may be broken by the sub-ring 14.

  Therefore, an embodiment in which no sub-ring is used will be described.

  FIG. 6 is a cross-sectional view of an essential part showing a second embodiment of the workpiece dividing apparatus according to the present invention.

  As shown in FIG. 6, the workpiece dividing apparatus 100 of this embodiment includes a refrigeration chuck table 10, a push-up ring 12, a wafer cover (dicing tape restraint) 20, and a light heating device 22. The light heating device 22 is, for example, a spot type halogen lamp heater. In addition, the light heating device 22 may be a laser, a flash lamp, or the like as long as it is irradiated with light and heated by radiation.

  In the case of such a light heating type device, the irradiation state of light can be visually confirmed. The region irradiated with light is heated by the radiation phenomenon, whereas the region not irradiated with light is not heated. That is, when irradiating light, the irradiation region can be visually recognized, so that the region where the irradiation can be visually recognized can be locally limited as a region heated by radiation.

  In the present embodiment, a spot-type halogen lamp heater is used as the light heating device 22. Specifically, a halogen spot heater LCB-50 (lamp rating 12 V / 100 W) manufactured by Infridge Industry Co., Ltd. was used. The focal length is 35 mm and the condensing diameter is 2 mm. However, in this embodiment, as shown in FIG. 11 to be described later, heating is not performed using a portion that is just focused, but the distance (irradiation distance) from the light source to the object is 46 mm, and the focal length is 35 mm. The offset is 11 mm and the irradiation diameter is 17.5 mm. The actual irradiation diameter is 15 mm, and an area having a diameter of 15 mm outside the work W of the dicing tape S is heated.

  FIG. 7 is an enlarged view of the thermo label TL affixed on the frame F of the workpiece 2, the dicing tape S outside the wafer cover 20, and the semiconductor wafer W side. FIG. 5 is an enlarged view of a thermo label after a process in which a dicing tape S outside the cover 20 is heated.

  Here, the thermo label TL is a type that turns red at a temperature of 50 ° C. or higher. As can be seen from the enlarged thermolabel after the process of FIG. 8, the wafer W side and the frame F side that are not irradiated with light do not reach 50 ° C.

  By using the spot type halogen lamp heater in this way, only the portion to be heated can be selectively (locally) heated, and the thermal stress on other portions can be minimized. .

  Further, as a halogen lamp power source, a Mutec Corporation halogen lamp power source KPS-100E-12 was used. The output of this halogen lamp power supply is rated voltage 12V. Also, it has a soft start (slow start) function to prevent inrush current from flowing through the halogen lamp.

  With these combinations, the time required to reach the heater maximum illuminance after a slow start of 0.75 seconds from the heater power ON command is within 3 seconds. This is a very short time compared to a warm air heater or an infrared heater. Similarly, the time from the maximum illuminance to power off is the same. Moreover, the change responsiveness from predetermined illuminance to another illuminance is also within 3 seconds. By using a halogen lamp in this way, a desired illuminance, that is, temperature can be obtained in a short time. This is difficult to realize with a general infrared heater or hot air heater. The good controllability is one reason why it is preferable to use a halogen lamp heater.

  Heat is generated in the same area by locally cooling the DAF portion on the backside of the wafer using the heat transfer phenomenon in the freezing chuck table and locally heating the slack portion of the outer periphery of the dicing tape using the radiation phenomenon by the halogen lamp heater. The states can be completely separated, and the DAF can be cooled and the dicing tape can be thermally contracted in the same stage or the same chamber. Thereby, after the DAF is cooled, there is no need to move the location due to the heat shrinkage of the dicing tape.

  In the present embodiment, as will be described below, in order to maintain the expanded state of the dicing tape S, the slack portion of the dicing tape S is removed using the wafer cover 20 and the light heating device 22 without using a sub-ring. The expanded state of the dicing tape S is maintained by selectively heating and tensioning.

  The wafer cover 20 has a bottomed cylindrical shape with a low height, and includes a bottom surface 20a and a side surface 20b. The bottom surface 20a is formed to be slightly larger than the semiconductor wafer W. Further, the wafer cover 20 is installed so as to be lifted and lowered by a cover lifting mechanism 21, and covers the semiconductor wafer W at the lowered position. On the other hand, the front end surface of the side surface 20 b of the wafer cover 20 is abutted with the front end surface of the raised push-up ring 12, whereby the semiconductor wafer W is completely sealed by the wafer cover 20.

  The light heating device 22 is arranged at a symmetrical position outside the wafer cover 20 and can be moved up and down by the wafer cover 20 and the heater lifting mechanism 23. As will be described in detail later, the periphery of the dicing tape S is lowered. The part is configured to be selectively heated. In the figure, two light heating devices 22 are arranged at symmetrical positions in the diameter direction of the workpiece 2, but the number of the light heating devices 22 is not limited to two. For example, four pieces may be arranged around the wafer cover 20 at intervals of 90 degrees.

  The operation of the present embodiment will be described below along the flowchart of FIG.

  First, in step S200 of FIG. 9, as shown in FIG. 6, the frame F of the workpiece 2 having the dicing tape S bonded to the back surface of the semiconductor wafer W via the DAF (D) is fixed by the frame fixing mechanism 18. And it arrange | positions so that the area | region where the semiconductor wafer W exists may be located on the freezing chuck table 10. FIG. In the semiconductor wafer W, as shown in FIG. 28, division lines to be divided are formed in a lattice shape in advance by laser irradiation or the like.

  Next, in step S210 of FIG. 9, the refrigeration chuck table 10 adsorbs the back surface of the work 2 by vacuum suction so as to contact the surface of the refrigeration chuck table 10 securely, and adheres to the work 2 by heat transfer. D) is cooled. The freezing chuck table 10 releases the vacuum suction after the workpiece 2 is vacuum-sucked for a predetermined time and cooled so that the DAF (D) becomes brittle.

  Next, in step S220 of FIG. 9, as shown in FIG. 10, the ring for raising and lowering is raised by the ring lifting mechanism 16, and the dicing tape S is expanded. In this case, the push-up ring 12 pushes up the dicing tape S to a height of 15 mm, for example, at a speed of 400 mm / sec, as in the previous embodiment.

  As a result, the dicing tape S is radially expanded from the center of the workpiece 2, and the semiconductor wafer W is divided into chips T along with the DAF (D) along the planned dividing line.

  Next, in step S230 of FIG. 9, as shown in FIG. 11, the wafer cover 20 and the light heating device 22 are lowered by the cover elevating mechanism 21 and the heater elevating mechanism 23, respectively, and the semiconductor wafer of the workpiece 2 is moved by the wafer cover 20. Cover the W part. At this time, as shown in FIG. 11, the front end surface of the side surface 20 b of the wafer cover 20 and the front end surface of the push-up ring 12 are brought into contact with each other, and the dicing tape S is placed between the wafer cover 20 and the push-up ring 12. Hold it.

  The force for gripping the dicing tape S between the wafer cover 20 and the push-up ring 12 is, for example, about 40 kgf.

  Next, in step S240 of FIG. 9, as shown in FIG. 12, while holding the dicing tape S between the wafer cover 20 and the push-up ring 12, the wafer cover 20 and the push-up ring 12 are connected to the semiconductor. The wafer is lowered to a position where the back surface of the dicing tape S on the lower side of the wafer W comes into contact with the upper surface of the freezing chuck table 10. As a result, the peripheral portion of the portion of the dicing tape S gripped by the wafer cover 20 and the push-up ring 12 is relaxed, and a slack portion is generated. At this time, the force for gripping the dicing tape S between the wafer cover 20 and the push-up ring 12 is maintained at 40 kgf.

  Next, in step S250 of FIG. 9, as shown in FIG. 13, only the loose dicing tape S portion outside the portion gripped by abutting the respective front end surfaces of the wafer cover 20 and the push-up ring 12 is shown. Then, the light heating device 22 is selectively heated by applying a spot light. At this time, if the area of the DAF (D) to which the workpiece is affixed is also heated at the same time, the DAF (D) may melt and the gap between the chips T may be lost. It is necessary to selectively heat only the slack portion other than the region where the heat treatment is performed.

  The dicing tape S slackened by this heating is tensioned, and the slack is gradually eliminated. For example, each of the light heating devices 22 is 100 W, and irradiates light to an area having a diameter of 20 mm. The gripping force between the wafer cover 20 and the push-up ring 12 is also maintained at 40 kgf.

  At this time, after the heating state is turned on after the light heating device 22 is turned on (after about 2 seconds), the biased state of the dicing tape S is not biased by heating only from a fixed position. Furthermore, it is preferable to rotate the light heating device 22 around the wafer cover 20 at a predetermined speed at a constant cycle. In this way, by rotating the light heating device 22 around the wafer cover 20 at a constant period, heating from various directions can prevent the dicing tape S from being biased. When the light heating device 22 is rotated, the heater lifting mechanism 23 not only simply moves the light heating device 22 up and down, but also has a function of a heater rotating mechanism that rotates the light heating device 22 at a constant cycle. May be.

  Here, the control method of the light heating device 22 will be described in detail. FIG. 14 is a plan view showing an example of the positional relationship between the light heating device 22 and the dicing tape S. The light heating device 22 is a spot type halogen lamp heater.

  In the example shown in FIG. 14, four light heating devices 22 are arranged around the dicing tape S symmetrically at equal intervals. In FIG. 14, the semiconductor wafer W and the frame F are omitted, and only one chip T is displayed in the center.

  In the example of FIG. 14, the chip T is substantially square, and each light heating device 22 is disposed at a position facing each side of the chip T. When the power source of each light heating device 22 is turned on at this position, the dicing tape S formed of the heat-shrinkable material is heated and contracts as indicated by an arrow J in the figure. As a result, the chip T is pulled in the X direction and the Y direction.

  Here, for example, it is assumed that the dicing tape S is not easily contracted in the X direction (horizontal direction) and is easily contracted in the Y direction (vertical direction). In order to eliminate such shrinkage anisotropy, the light heating device 22 arranged in the X direction, which is hard to shrink, is more (halogen lamp heater) than the light heating device 22 arranged in the Y direction, which is easy to shrink. Set the applied voltage to a higher value. As a result, the dicing tape S is uniformly contracted in the vertical direction and the horizontal direction, and each chip T is pulled evenly in the outer peripheral direction, so that the chips T do not stick to each other and the arrangement is not shifted.

  Further, at this time, as indicated by an arrow K in the figure, the light heating device (spot type halogen lamp heater) 22 is rotated and scanned around the dicing tape S by the heater lifting mechanism 23.

  FIG. 15 shows how the optical heating device 22 is rotationally scanned.

  First, heating is performed by turning on the power of the light heating device 22 (not shown in FIG. 15) at a position indicated by reference numeral 1 in FIG. At this time, as described above, the dicing tape S is not easily contracted in the X direction (lateral direction) and is easily contracted in the Y direction (vertical direction). The applied voltage is set to be higher than that of the light heating device 22 at the position indicated by the symbol L.

  Next, the power of the light heating device 22 is turned off or a voltage that does not contribute to heating is applied, and the light heating device 22 is moved 45 by the heater lifting mechanism 23 to the position of the reference numeral 2, which is an intermediate position of the reference numeral 1. Rotate degrees.

  Next, the dicing tape S is heated by turning on the power of the light heating device 22 again at the position of reference numeral 2. Since the position indicated by reference numeral 2 is an intermediate direction between the X direction and the Y direction, the applied voltages of all the light heating devices 22 are made equal.

  In this way, the dicing tape S can be evenly contracted in all directions of the horizontal direction, the vertical direction, and the oblique direction.

  Note that the number of the light heating devices 22 is not limited to four as in this example, and one light heating device is added between each of the four light heating devices 22 shown in FIG. A single light heating device 22 may be provided.

  FIG. 16 shows an example provided with eight light heating devices. In the example shown in FIG. 16, one light heating device 22 is arranged between each light heating device 22 with respect to the four light heating devices 22 in FIG. 14, and eight light heating devices 22 in total. Are arranged around the dicing tape S at equal intervals. Also in this case, the eight light heating devices 22 can be moved up and down with respect to the dicing tape S by the heater lifting mechanism 23 and can be rotated and scanned around the same.

  FIG. 17 shows how the eight light heating devices 22 are rotationally scanned.

  For example, the eight light heating devices 22 initially heat the peripheral portion of the dicing tape S at the position indicated by reference numeral 1 in FIG. Next, as indicated by an arrow K in FIG. 17, the light heating device 22 is rotated by 22.5 degrees (360 degrees ÷ 8 ÷ 2) by the heater lifting mechanism 23 to the position of 2. During this rotation, the light heating device 22 turns off the power or applies a voltage that does not contribute to heating. Then, the peripheral portion of the dicing tape S is heated at the position indicated by reference numeral 2 in FIG.

  At this time, as in the previous example, when the dicing tape S is less likely to contract in the X direction (horizontal direction) than the Y direction (vertical direction) with respect to the chip T, it is indicated by a broken line in the figure. The light heating device 22 in the range H is set to have a higher applied voltage than the light heating device 22 in the range L indicated by a broken line in the drawing.

  Note that the number of the light heating devices 22 is not limited to four or eight as in these examples, but is at least four or more and symmetrically arranged along the outer periphery of the dicing tape S at equal intervals. I can do it. For example, the six light heating devices can be arranged symmetrically at equal intervals along the outer periphery of the dicing tape S, and thus may be six.

  Further, two light heating devices may be added between the four light heating devices 22 in FIG. 14 to obtain twelve, or three light heating devices 22 in FIG. It is good also as 16 by adding a light heating apparatus. Thus, the number of the light heating devices 22 is preferably a multiple of four.

  In this way, at least four or more light heating devices are evenly arranged around the dicing tape S, and in the direction in which the dicing tape S is difficult to contract, the voltage applied to the light heating device is increased to heat the device. Thus, by repeating the heating by the light heating device and the rotation by a predetermined angle, the dicing tape S can be uniformly shrunk in all the horizontal, vertical and oblique directions.

  Here, it is assumed that eight light heating devices 22 are arranged at equal intervals along the periphery of the dicing tape S as shown in FIG. Similarly to the example of FIG. 16, it is assumed that the dicing tape S is less likely to contract in the X direction (horizontal direction) shown with respect to the chip T than in the Y direction (vertical direction).

  Next, at the position indicated by reference numeral 1 in FIG. 17, the power supply of the eight light heating devices 22 is turned on to heat the slack outer peripheral portion of the dicing tape S. At this time, in the region surrounded by the broken line H in FIG. 17, the applied voltage of the light heating device 22 is set higher than in the region surrounded by the broken line L. Thereby, the horizontal direction (X direction) in which the dicing tape S is difficult to contract can be contracted in the same manner as the direction in which the dicing tape S easily contracts (Y direction), and the anisotropy of the contraction can be suppressed.

  Next, the power of the light heating device 22 is turned off or a voltage that does not contribute to heating is applied and the light heating device 22 is moved to a position indicated by reference numeral 2 by the heater lifting mechanism 23 as indicated by an arrow K in FIG. Rotate.

  Next, at the position of reference numeral 2 in FIG. 17, the light heating device 22 is turned on to heat the outer peripheral portion of the dicing tape S. At this time, in the region surrounded by the broken line H in FIG. 17, the applied voltage of the light heating device 22 is set higher than the region surrounded by the broken line L.

  Then, the power source of the light heating device 22 is turned off and the light heating device 22 is raised to the standby position by the heater lifting mechanism 23.

  Finally, the wafer cover 20 is raised to the standby position in the same manner as the light heating device 22, and the push-up ring 12 is also lowered to the standby position to release the dicing tape S from being expanded. Then, the frame F is removed and the work is conveyed to the next process. Alternatively, it is stored in a predetermined place until the inspection of the sample chip is completed.

  In this way, by selectively and evenly heating only the slack portion of the dicing tape S by the light heating device, the dicing tape S is uniformly shrunk in all directions, and the interval and arrangement of the divided chips T are changed. Can be maintained. Therefore, even if the work picking up the sample chip is removed from the die bonder and stored until the inspection of the sample chip is completed, the expanded state of the dicing tape S is maintained, so that the expanded dicing tape S is returned to its original state. Thus, the interval between the chips T is not narrowed and the chips do not come into contact with each other.

  Further, another heating control method when eight light heating devices are arranged at equal intervals along the periphery of the dicing tape S will be described.

  That is, for example, as shown in FIG. 16, spot-type halogen lamp heaters are arranged as eight light heating devices 22 at equal intervals along the periphery of the dicing tape S. However, at this time, the chip T is not substantially square as shown in FIG. 16, and the length ratio (aspect ratio) in the X direction (horizontal direction) and the Y direction (vertical direction) in the drawing is 1: 2. 4 is a vertically long rectangle (see FIG. 19).

  The light heating devices 22 are arranged around the dicing tape S at intervals of 45 degrees. This 45 degree interval is divided into eight equal parts, and each light heating device 22 is rotated along the periphery of the dicing tape S by 5.6 degrees, and is heated at that position every time it rotates 5.6 degrees. . At this time, initially, in FIG. 18, the voltage applied to the halogen lamp heater as the light heating device 22 is 12V at the Left and Right positions and 5V at the Top and Bottom positions.

  Thus, after heating 8 times while rotating by 5.6 degrees, the next is to start from a position shifted by 2.8 degrees, which is half 5.6 degrees from the first position. This time, the voltage applied to the halogen lamp heater is 12V at the Left and Right positions and 11V at the Top and Bottom positions. And it heats 8 times, rotating 5.6 degrees at a time.

  In this way, the intervals between the chips T on the dicing tape S are set at five points as shown in FIG. 19 at five locations of Center, Left, Right, Top and Bottom shown in FIG. Measurements were made in two directions, horizontal and vertical, respectively.

  In FIG. 20, the measurement result for every point is shown about each location. From this result, it can be seen that the distance between chips is about 20 to 30 on average in any place by the heating control as described above, and the difference is not so large.

  On the other hand, for comparison, FIG. 21 shows a measurement result in the case where heating is simply performed from the entire periphery of the dicing tape S without performing such heating control.

  Referring to FIG. 21, when the aspect ratio of the chip T is 1: 2.4 and anisotropy, when the same heating is performed from all directions, the chip interval depends on the location and direction on the dicing tape S. However, it can be seen that, on average, 10 to 50 units have changed greatly.

  Thus, by performing the heating control as described above, the dicing tape S is contracted in the same manner in all directions even when the chip has a shape that is greatly deviated from the square and has anisotropy. be able to. On the contrary, even when the chip is isotropic and has no anisotropy and the dicing tape S has anisotropy, the above heating control method can be used.

  In the examples described so far, the light heating device is a spot-type halogen lamp heater. However, since the wafer cover 20 exists, a warm air heater can be used. In other words, if the hot air is blown only to a local area from the nozzle or the like, the hot air can be prevented from going directly to the area of the semiconductor wafer W by the wafer cover 20, so that the dicing tape S It is possible to selectively heat only the slack portion.

  Moreover, in this embodiment, since it heats with the thermal radiation by the optical heating apparatus 22, only the loose part of the dicing tape S can be heated locally (selectively). In particular, in this embodiment, since the semiconductor wafer W is covered with the wafer cover 20, heat can be shielded and the DAF (D) to which the workpiece is attached can be prevented from being heated by the light heating device 22. Further, local heating by the light heating device 22 is possible.

  Further, since the wafer cover 20 and the push-up ring 12 grip the vicinity of the slack portion of the dicing tape S, the wafer cover 20 and the push-up ring 12 are also heated by heating the slack portion. However, this heat escapes through the wafer cover 20 and the push-up ring 12 by heat conduction. Accordingly, the DAF (D) to which the work surrounded by the wafer cover 20 and the push-up ring 12 is attached is thermally shielded and is not heated.

  In this regard, conventionally, since heating was performed by warm air, the whole was heated by heat convection, so that only the slack portion of the dicing tape S could not be selectively heated. In addition, the cooling of DAF (D) is performed in an atmosphere cooling system that cools the entire unit as in a refrigerator, so selective cooling cannot be performed, and cooling and heating can be performed with one unit. Could not do.

  On the other hand, in the present embodiment, the DAF (D) with which the workpiece is stuck is also used for cooling the DAF (D) because heat transfer is performed by adsorbing the workpiece to the workpiece 2 by being sucked by the freezing chuck table 10. Only this part can be selectively cooled.

  Therefore, in this embodiment, it is possible to perform cooling of the DAF (D) to which the work is stuck and heating of the slack dicing tape S other than the area to which the work is stuck in one unit.

  Thus, the result of heating the slack part of the dicing tape S of the outer peripheral part of the wafer cover 20 is shown in FIG.22 and FIG.23.

  22 and 23 are thermotracer screens in which the dicing tape S selectively heated by the light heating device 22 is measured to be thermally contracted.

  22 and 23, the slack dicing tape S outside the wafer cover 20 is locally heated by a spot type halogen lamp heater. As a result, the temperature of the heating center of the dicing tape S indicated by symbol A in the figure has reached nearly 140 degrees. On the other hand, the temperature of the wafer cover 20 is about 50 degrees, and the temperature of the frame fixing mechanism (frame restraint) 18 is also about 40 degrees. In addition, although the part of the code | symbol B of a figure is also about 90 degree | times, this contains the regular reflection light from a halogen lamp, and is not measured correctly.

  In this way, by heating with the spot type halogen heater, only the slack portion of the dicing tape S can be heated and selectively heated so as not to raise the temperature of the other portions.

  Next, a description will be given of the result of a heating / shrinking experiment performed on each of the tapes described above using a light heating device using radiation.

  The process time was a standard time for PO tape. Wafer cooling was performed in 20 seconds from room temperature to −10 ° C. The expand lifted the 15 mm push-up ring in 3 seconds. The slack formation time on the dicing tape was 7 seconds. The heat shrinkage is set to 24 seconds + 6 seconds with a slow start and a moving time of the light heating device of 6 seconds × 4 steps. Alternatively, the heat shrinkage is set to 48 seconds + 10 seconds in 6 seconds × 8 steps for the slow start and the moving time of the light heating device.

  The waiting time for dicing tape curing is 30 seconds, and further 10 seconds for loading, unloading, centering and the like. The total of the above is 100 seconds or 128 seconds. Note that 8 steps are for a small chip.

  At this time, since the light heating device is a spot type, the amount of input heat per unit area at the light irradiation position is large. As a result, not only the PO-based dicing tape having heat shrinkage but also the PVC-based dicing tape could be contracted.

  For example, D175, which is the above-mentioned PO tape manufactured by Lintec, can be expanded by 5 mm in the tape roll direction (MD) and 3 mm in the width direction (TD).

  In this way, when the dicing tape S is heated for a predetermined time and the dicing tape S is tensioned and loosening is eliminated, heating by the light heating device 22 (rotation of the light heating device 22) is stopped. At this time, holding of the dicing tape S by the wafer cover 20 and the push-up ring 12 is continued for about 30 seconds until the dicing tape S is cured.

  Finally, in step S260 of FIG. 9, as shown in FIG. 24, the wafer cover 20 (and the light heating device 22) is raised and the push-up ring 12 is lowered to release the holding of the dicing tape S. . During this time, curing may be promoted by cooling the heat-shrinkable part by vacuum suction by the freezing chuck table 10. In this way, the dicing tape S is vacuum-adsorbed and cooled by the freezing chuck table 10 so that the heated portion of the outer peripheral portion of the dicing tape S is removed, so that it is shorter than the normal room temperature. The dicing tape S can be cured. Thereafter, when the vacuum chucking by the freezing chuck table 10 is performed, the vacuum chucking is also stopped.

  In this way, it is possible to manufacture the workpiece 2 in which the distance between the chips T is sufficiently maintained and the surrounding dicing tape S is not loose. FIG. 25 shows a photograph of the workpiece after the heat shrinking process manufactured in this way. FIG. 25 is an image taken from the back side of the tape, but it can be clearly confirmed that white gaps are vertically and horizontally in the wafer, and it can be seen that the chips are maintained in a separated state.

  On the other hand, when the cooling / expansion unit and the heat shrinking unit are separate units as in the prior art and it is necessary to transport the workpiece between the units, the slack dicing tape droops greatly and becomes indefinite. Then, as shown in a cross-sectional view in FIG. 26, the upper surfaces of the chips T separated with DAF (D) on the dicing tape S come into contact with each other. In this way, if there is no gap between adjacent chips, the chip may be damaged in the subsequent process, leading to a decrease in quality.

  However, according to the present embodiment, as shown in FIG. 25, the chips separated after the heat shrinking process are maintained in a separated state, and the chip quality and yield are not reduced.

  In the second embodiment described above, the portion of the semiconductor wafer W of the workpiece 2 is covered with the wafer cover and is thermally shielded from the light heating device 22 as a heating means. However, the light heating device 22 is spot-like. Since it is possible to selectively heat the substrate with heat, it is preferable to thermally shield it with a wafer cover, but shielding with a wafer cover is not always necessary.

  Accordingly, a modification of the second embodiment in which the use of the wafer cover 20 is stopped from the second embodiment is also conceivable.

  The operation of such a modification will be described below with reference to the flowchart of FIG.

  As the workpiece dividing apparatus, it is assumed that the wafer cover 20 is removed from the apparatus configuration of the second embodiment shown in FIG. 6, or the apparatus configuration is the same and the wafer cover 20 is simply not used.

  First, in step S300 of FIG. 27, the frame F of the work 2 having the dicing tape S bonded to the back surface of the semiconductor wafer W via the DAF (D) is fixed by the frame fixing mechanism 18. And it arrange | positions so that the area | region where the semiconductor wafer W exists may be located on the freezing chuck table 10. FIG.

  Next, in step S310 in FIG. 27, the back surface of the work 2 is adsorbed by vacuum suction by the freezing chuck table 10 to be surely brought into contact with the surface of the freezing chuck table 10, and the work 2 is cooled by heat transfer.

  Next, in step S320 of FIG. 27, the ring 12 for raising is raised by the ring raising / lowering mechanism 16, and the dicing tape S is expanded.

  Next, in step S330 of FIG. 27, the push-up ring 12 is lowered to a position where the back surface of the dicing tape S on the lower side of the semiconductor wafer W comes into contact with the upper surface of the freezing chuck table 10. Thereby, the peripheral part of the dicing tape S relaxes and a slack part occurs.

  Next, in step S340 of FIG. 27, only the relaxed dicing tape S portion outside the push-up ring 12 is selectively heated by applying the spot light with the light heating device 22. Thereby, the slack portion of the dicing tape S is tensioned by heat and the slack is eliminated. At this time, the heat applied to the relaxed portion of the dicing tape S is also transmitted to the other portions of the dicing tape S, but the heat is transferred through the push-up ring 12 in contact with the dicing tape S. Because of this, the heat escapes, so that it is difficult for the heat to be transmitted to the DAF (D) region.

  At this time, the dicing tape is a polymer and has a low thermal conductivity, whereas the push-up ring is made of metal or the like, so that heat is easily transferred to the push-up ring as it is. If the raising ring is set to have a higher thermal conductivity than the dicing tape, heat will not be transmitted to the DAF in particular.

  At this time, the DAF (D) region may be simultaneously cooled by the freezing chuck table 10.

  Finally, in step S350 in FIG. 27, the push-up ring 12 is lowered and moved to the lowered position (standby position). During this time, hardening of the slack dicing tape S may be promoted by cooling the heat shrinkage portion by vacuum suction by the freezing chuck table 10. In this way, by vacuum suction and cooling by the freezing chuck table 10, the heat of the heated portion of the outer peripheral portion of the dicing tape S is taken, so that the dicing tape S can be shortened in a short time compared with normal room temperature. Can be cured.

  As a result, a work having a sufficiently secured chip interval is formed, and the processing in the next step is facilitated.

  The work dividing apparatus and the work dividing method of the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.

  For example, the area of the dicing tape that has been irradiated with the light has never been able to visually recognize that the light has been irradiated, but the wafer area where the DAF is present is sufficient even if the irradiation area is not visually recognized by infrared rays or the like. It is only necessary that the predetermined area of the outer peripheral dicing tape can be relatively locally heated on the premise of being locally cooled. For example, if heat transfer by a refrigeration chuck table is used in the wafer region, the outer peripheral portion may be heat supply by infrared radiation or convection.

  The freezing chuck table also does not have a freezing function using a Peltier element. For example, the inner surface of the wafer is cooled in advance, and the cooled state becomes a simple metal chuck or porous ceramic chuck having a large heat capacity. If it is possible to maintain its pre-cooled state by simply adsorbing and securing a sufficient temperature difference compared to the outer peripheral area of the dicing tape, it is substantially regarded as a freezing chuck in a relative sense. sell.

  Also, with the push-up ring, the heat region can be divided into the wafer area region and the outer peripheral region of the dicing tape, the cooling state is formed in the wafer area, and the heating state is formed in the outer periphery of the dicing tape at the same location. If it is.

  DESCRIPTION OF SYMBOLS 1,100 ... Work division | segmentation apparatus, 2 ... Work, 10 ... Freezing chuck table, 12 ... Push-up ring, 14 ... Sub ring, 16 ... Ring raising / lowering mechanism, 18 ... Frame fixing mechanism, 20 ... Wafer cover, 21 ... Cover lifting mechanism, 22 ... light heating device, 23 ... heater lifting mechanism (rotating mechanism), D ... die attach film (DAF), F ... frame, S ... dicing tape, T ... chip, W ... semiconductor wafer

Claims (8)

In a work dividing device that divides a work affixed to a dicing tape via a die attach film into individual chips along a pre-formed dividing line,
A workpiece holding position for holding the workpiece;
In the same position that holds the workpiece,
A workpiece made of a semiconductor wafer having a parting line
Wherein the area of the work, selectively and locally the die attach film by only by that cooled heat transfer Ru contacting the frozen chuck table on the dicing tape comprising a cutting-scheduled line of affixed to said workpiece to said die attach film and selective cooling means for cooled,
After the cooling, the dicing tape is expanded, and the work dividing means for dividing the work and the die attach film,
Heating means for heating a portion other than a region where the work of the dicing tape is pasted via the die attach film, and eliminating slack due to the expanding of the dicing tape;
A workpiece dividing device characterized by comprising:   2. The workpiece dividing apparatus according to claim 1, wherein the selective cooling unit is a cooling unit that cools the workpiece in contact with the dicing tape attached via the die attach film.   The said workpiece | work division means is a ring for a thrust which pushes up and expands the outer peripheral part of the said cooled workpiece | work relatively from the outer peripheral support part of the said dicing tape, The Claim 1 or 2 characterized by the above-mentioned. Work dividing device.   It is a workpiece | work division | segmentation apparatus in any one of Claims 1-3, Comprising: It has a cylindrical shape with a bottom so that the area | region of the said expanded workpiece | work may be covered, is arrange | positioned so that raising / lowering is possible, A work dividing apparatus comprising a wafer cover for covering a work, wherein the heating means is arranged to be movable up and down around the wafer cover.   The workpiece dividing means is a push-up ring that expands the outer peripheral portion of the cooled workpiece relative to the outer peripheral support portion of the dicing tape to expand, and when the wafer cover is lowered to cover the workpiece 5. The workpiece division according to claim 4, wherein a tip end surface of a side portion of the wafer cover is abutted with a tip end surface of the expanding push-up ring to seal the workpiece inside the wafer cover. apparatus. In a work dividing method for dividing a work affixed to a dicing tape via a die attach film into individual chips along a pre-formed dividing line,
A workpiece holding position for holding the workpiece;
In the position for holding the workpiece, the area of the workpiece including the dividing lines of the workpiece that is attached to the die attach film, by only by that cooled heat transfer Ru contacting the frozen chuck table on the dicing tape A selective cooling step of selectively and locally cooling the die attach film ;
After the cooling, the work dividing step of expanding the dicing tape and dividing the work and the die attach film,
A heating step of heating a portion other than an area where the work of the dicing tape is pasted via the die attach film, and eliminating slack due to the expanding of the dicing tape;
A work dividing method characterized by comprising:   The work dividing method according to claim 6, wherein in the work dividing step, the outer peripheral portion of the cooled workpiece is expanded by being pushed up relatively from the outer peripheral supporting portion of the dicing tape by a push-up ring. . The workpiece dividing method according to claim 7, further comprising a wafer cover having a bottomed cylindrical shape so as to be able to move up and down so as to cover the expanded workpiece region, and the wafer cover is lowered The cylindrical tip surface is abutted with the tip surface of the expanding push-up ring, and has a workpiece covering step for sealing the workpiece inside the wafer cover,
In the heating process, the periphery of the wafer cover covering the workpiece is heated.