JP7564993B2 - Workpiece dividing device and workpiece dividing method - Google Patents

Description

The present invention relates to a workpiece dividing device and a workpiece dividing method, and in particular to a workpiece dividing device and a workpiece dividing method for dividing a workpiece such as a semiconductor wafer into individual chips along a planned division line.

Conventionally, in the manufacture of semiconductor chips (hereafter referred to as chips), a workpiece dividing device is known that divides a semiconductor wafer (hereafter referred to as wafer) into individual chips along the dividing lines, the wafer having dividing lines formed therein in advance by half-cutting with a dicing blade or forming modified regions by laser irradiation (see Patent Document 1, etc.).

Figure 11 is an explanatory diagram of a wafer unit 2 to which a disk-shaped wafer 1 to be divided by a workpiece dividing device is attached, with Figure 11(A) being a perspective view of the wafer unit 2 and Figure 11(B) being a vertical cross-sectional view of the wafer unit 2.

The wafer 1 is attached to the center of a dicing tape (also called an expansion tape or adhesive sheet) 3 that is approximately 100 μm thick and has an adhesive layer formed on one side, and the dicing tape 3 is fixed at its outer periphery to a rigid ring-shaped frame 4.

In the workpiece dividing device, the frame 4 of the wafer unit 2 is fixed by abutting it against a fixing part (also called a frame fixing mechanism) 7 shown by a two-dot chain line. After this, an expand ring (also called a push-up ring) 8 shown by a two-dot chain line is moved upward from below the wafer unit 2, and the dicing tape 3 is pressed by this expand ring 8 to expand radially. The tension of the dicing tape 3 generated at this time is applied to the planned dividing lines 5 of the wafer 1, dividing the wafer 1 into individual chips 6.

In this specification, the circular area of the dicing tape 3 to which the wafer 1 is attached is referred to as the central area 3A, the doughnut-shaped area between the outer edge of the central area 3A (the outer edge of the wafer 1) and the inner edge of the frame 4 is referred to as the annular area 3B, and the doughnut-shaped area of the outermost periphery fixed to the frame 4 is referred to as the fixed area 3C. The annular area 3B is the area that is expanded by being pressed against the expand ring 8.

It is known that in a workpiece dividing device, the force required to divide the wafer 1, i.e., the tension that must be generated in the annular region 3B to divide the wafer 1, must be higher as the number of planned dividing lines 5 increases. Regarding the number of planned dividing lines 5, for example, when the chip size is 5 mm on a wafer 1 with a diameter of 300 mm, approximately 120 planned dividing lines 5 (60 in each of the X and Y directions) are formed, and when the chip size is 1 mm, approximately 600 planned dividing lines 5 are formed. Therefore, the tension that must be generated in the annular region 3B must be higher as the chip size becomes smaller.

The inner diameter (diameter of the inner edge of the frame) of the frame 4 on which the 300 mm diameter wafer 1 is mounted is set to 350 mm according to the SEMI standard (G74-0699 Specifications for Tape Frames for 300 mm Wafers). According to this standard, as shown in the vertical cross-sectional view of the wafer unit 2 in FIG. 12, an annular region 3B with a width of 25 mm exists between the outer edge of the wafer 1 and the inner edge of the frame 4. Also, as shown in the vertical cross-sectional views of the main parts of the workpiece dividing device shown in FIGS. 13(A) and (B), the fixing part 7 that fixes the frame 4 is installed at a position spaced outward from the annular region 3B in the in-plane direction of the dicing tape 3 indicated by the arrow A so as not to come into contact with the annular region 3B expanded by the expand ring 8.

Here, the force that divides the wafer 1 generated by the upward movement of the expand ring 8 is decomposed into three forces: (i) a force that expands the entire area of the annular region 3B, (ii) a force that divides the wafer 1 into chips 6, and (iii) a force that expands the dicing tape 3 between adjacent chips 6.

As shown in the operation diagram of the workpiece dividing device in Figures 14(A) to (E), when the expand ring 8 comes into contact with the annular region 3B of the dicing tape 3 and the dicing tape 3 begins to expand due to the rising movement of the expand ring 8 (Figure 14(A)), the annular region 3B, which has the lowest spring constant, begins to expand first (Figure 14(B)). This generates tension in the annular region 3B, and when this tension increases to a certain extent, the increased tension is transmitted to the wafer 1, and the division of the wafer 1 into chips 6 begins (Figure 14(C)). When the wafer 1 is divided into individual chips 6, the expansion of the annular region 3B and the expansion of the dicing tape 3 between the chips 6 proceed simultaneously (Figures 14(D) to (E)).

In the conventional workpiece dividing device, when a wafer 1 having a diameter of 300 mm has a chip size of 5 mm or more, the tension generated in the annular region 3B can divide the wafer 1 into individual chips 6 without any problems. However, as the circuit patterns formed on the wafer 1 become finer, chips with smaller chip sizes of 1 mm or less have also appeared. In this case, the force required to divide the wafer 1 increases due to an increase in the number of division lines 5 that divide the wafer 1, and sometimes a force greater than the tension caused by the expansion of the annular region 3B is required. This causes a problem that, as shown in the vertical cross-sectional view of the wafer unit 2 in Figure 15, even after the expansion operation by the expand ring 8 is completed, some of the division lines 5 formed on the wafer 1 remain undivided.

This problem of the planned division line 5 not being divided cannot be solved even if the expansion amount or expansion speed of the dicing tape 3 is increased. For example, if the expansion amount of the dicing tape 3 is increased, the annular region 3B begins to undergo plastic deformation. Since the spring constant of the annular region 3B during plastic deformation is smaller than the spring constant during elastic deformation, no tension is generated to divide the wafer 1 into individual chips 6 in the region of the annular region 3B that exceeds the elastic deformation. On the other hand, even if the expansion speed of the dicing tape 3 is increased, a part of the annular region 3B begins to undergo plastic deformation, so no tension is generated to divide the wafer 1 into individual chips 6. This is because the frequency response of the dicing tape 3 is low, and the force is not transmitted to the entire dicing tape 3 without time lag.

As an example of a device that solves the above problems, Patent Document 2 discloses a tape expansion device (workpiece dividing device) equipped with a cold air supplying means. According to Patent Document 2, the cold air supplying means is operated to supply cold air into the processing space, and the processing space is cooled to, for example, below zero, thereby cooling the dicing tape.

As in Patent Document 2, by cooling the dicing tape, the dicing tape can be expanded with a larger spring constant. This makes it possible to increase the tension generated in the annular region 3B shown in FIG. 12 compared to a dicing tape that is not cooled, making it possible to separate even small chips into individual chips.

On the other hand, in the field of workpiece dividing devices, it is also required to prevent deterioration of chip quality caused by contact between chips after division by maintaining the expanded state of the dicing tape expanded by the expanding ring.

As a work division device that satisfies this requirement, a work division device equipped with a sub-ring is disclosed in Patent Document 3. The sub-ring of Patent Document 3 has the function of holding the dicing tape expanded by the expand ring in an expanded state, and is configured to have a diameter larger than the inner diameter of the frame. The sub-ring is raised toward the dicing tape from the back side of the dicing tape. Then, immediately after the sub-ring passes through the frame, a fitting portion (also called a lip) provided on the outer periphery of the sub-ring is inserted between the outer periphery of the dicing tape and the surface of the frame. As a result, the expanded state of the dicing tape is maintained even after the expansion of the dicing tape by the expand ring is completed. By maintaining the expanded state of the dicing tape in this way, it is possible to prevent the dicing tape from loosening, and therefore it is possible to prevent deterioration of the quality of the chips caused by contact between the chips.

JP 2016-149581 A JP 2016-12585 A JP 2013-51368 A

However, the workpiece dividing devices in Patent Documents 1 and 2 do not have a sub-ring like the one in Patent Document 3, which may lead to problems with reduced chip quality due to contact between the chips after division.

On the other hand, if the sub-ring of Patent Document 3 is mounted on the work division device of Patent Document 2, which cools the dicing tape with cold air, a problem occurs in which the resin fitting portion of the sub-ring hardens and becomes brittle in the low-temperature environment. This problem raises the risk of the fitting portion of the sub-ring being damaged when it is inserted between the outer periphery of the dicing tape and the surface of the frame. Therefore, it is difficult to mount the sub-ring of Patent Document 3 on the work division device of Patent Document 2.

As such, there is no conventional workpiece dividing device that can solve the problem of not dividing the intended dividing line that occurs when the chip size is small, while also solving the problem of reduced chip quality caused by chips coming into contact with each other after division, and there has been a demand for the realization of such a device.

The present invention was made in consideration of these problems, and aims to provide a work division device and a work division method that can simultaneously solve the problem of non-division of the planned division line that occurs when the chip size is small, and the problem of reduced chip quality caused by contact between chips after division.

In order to achieve the object of the present invention, the work division device of the present invention is a work division device in which the outer periphery of a dicing tape is fixed to a ring-shaped frame having an inner diameter larger than the outer diameter of the work, and the work attached to the dicing tape is divided into individual chips along the planned division lines. The work division device is arranged on the back side of the dicing tape opposite the surface on which the work is attached, and is formed in a ring shape with an opening smaller than the inner diameter of the frame and larger than the outer diameter of the work. The expand ring is moved in a direction approaching the dicing tape relatively to press the dicing tape to expand it. The expansion retaining ring is arranged on the back side of the dicing tape opposite the work attachment surface and is formed in a ring shape with an elastically deformable fitting portion larger than the inner diameter of the frame. When the dicing tape is in a state where it is expanded by the expansion ring, the fitting portion fits onto the surface of the frame, thereby maintaining the expanded state of the dicing tape. The expansion retaining ring is provided with a cooling portion that cools the space including the expansion ring and the expansion retaining ring, and a heating portion that heats the fitting portion cooled by the cooling portion before the fitting portion of the expansion retaining ring fits onto the surface of the frame.

According to the workpiece dividing device of the present invention, the dicing tape is cooled by cold air from the cooling section, and the dicing tape is expanded by the expanding ring while the spring constant of the dicing tape is increased. As a result, the workpiece dividing device of the present invention can divide even small chips into individual chips. At this time, the fitting portion of the expansion retaining ring is cooled by the cold air and its properties change from an elastic state to a brittle state, so before this fitting portion is fitted to the surface of the frame, the fitting portion is heated by the heating section. As a result, the fitting portion is restored from a brittle state to an elastic state, and is then fitted to the surface of the frame to maintain the expanded state of the dicing tape.

As described above, the workpiece dividing device of the present invention can simultaneously solve the problem of non-division of the dividing line that occurs when the chip size is small, and the problem of reduced chip quality caused by contact between chips after division.

In one aspect of the workpiece dividing device of the present invention, the cooling unit preferably supplies cold air to the space at a temperature at which the dicing tape becomes brittle, and the heating unit preferably heats the mating portion to a temperature that exceeds the temperature of the cold air, thereby making the mating portion elastic. As a result, the spring constant of the dicing tape increases due to the cold air, and the mating portion recovers from a brittle state to an elastic state.

In one aspect of the workpiece dividing device of the present invention, the heating section is preferably a heat supply section that supplies heat above room temperature to the fitting section. This ensures that the fitting section recovers from a brittle state to an elastic state.

In one aspect of the workpiece dividing device of the present invention, the heating section is preferably an air supply section that supplies room temperature air to the fitting section. This ensures that the fitting section recovers from a brittle state to an elastic state.

In order to achieve the object of the present invention, the workpiece dividing method of the present invention, in which the outer periphery of the dicing tape is fixed to a ring-shaped frame having an inner diameter larger than the outer diameter of the workpiece, and the workpiece attached to the dicing tape is divided into individual chips along a planned division line, includes a cooling step of cooling the dicing tape with cold air, an expansion step of expanding the dicing tape by moving an expansion ring arranged on the back side of the dicing tape opposite the workpiece attachment surface in a direction relatively closer to the dicing tape, thereby pressing the annular area of the dicing tape between the outer edge of the workpiece and the inner edge of the frame with the expansion ring, a heating step of heating an elastically deformable fitting portion formed on the outer periphery of the expansion retaining ring arranged on the back side of the dicing tape opposite the workpiece attachment surface, and an expansion state maintaining step of maintaining the expanded state of the dicing tape expanded by the expansion step by moving the expansion retaining ring in a direction relatively closer to the dicing tape, thereby fitting the heated fitting portion to the surface of the frame.

The workpiece division method of the present invention can simultaneously solve the problem of non-division of the planned division line that occurs when the chip size is small, and the problem of reduced chip quality caused by contact between chips after division.

In one aspect of the workpiece dividing method of the present invention, the cooling step preferably supplies the dicing tape with cold air at a temperature at which the dicing tape becomes brittle, and the heating step preferably heats the mating portion at a temperature higher than the temperature of the cold air to make the mating portion elastic. This increases the spring constant of the dicing tape due to the cold air, and the mating portion recovers from a brittle state to an elastic state.

In one aspect of the workpiece dividing method of the present invention, the heating step preferably supplies heat above room temperature to the fitting portion. This ensures that the fitting portion recovers from its brittle state to its elastic state.

In one aspect of the workpiece dividing method of the present invention, the heating step preferably involves supplying room temperature air to the mating portion. This ensures that the mating portion recovers from its brittle state to its elastic state.

The present invention can simultaneously solve the problem of non-division of planned division lines that occurs when the chip size is small, and the problem of deterioration of chip quality due to contact between chips after division.

A structural diagram of a main part of a dividing stage of a workpiece dividing device according to an embodiment. FIG. 2 is an enlarged perspective view of a main part of the split stage shown in FIG. FIG. 1 is a longitudinal sectional view of a main portion of a wafer unit showing the shape of an annular region during expansion. A vertical cross-sectional view showing the expansion of the dicing tape by the expansion retaining ring. FIG. 5 is an enlarged cross-sectional view of a main portion of FIG. Block diagram showing the control system of the workpiece separation device 1 is a flowchart showing an example of a wafer dividing method. Explanation of the operation of the workpiece dividing device Explanation of the operation of the workpiece dividing device An explanatory diagram in which an air supply unit that supplies room temperature air is used as a heating unit. An explanatory diagram of a wafer unit with a wafer attached Vertical cross-sectional view of the wafer unit Side view of the main part of the workpiece dividing device Operation diagram of workpiece dividing device A longitudinal sectional view of a wafer unit into which wafers are separated.

Below, preferred embodiments of the workpiece dividing device and workpiece dividing method according to the present invention will be described in detail with reference to the attached drawings. The present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments within the scope of the present invention.

Figure 1 is a vertical cross-sectional view of the main part of a dividing stage provided in a work dividing device 10 according to an embodiment, and Figure 2 is an enlarged perspective view of the main part of the dividing stage. Note that the size of the wafer unit divided by the work dividing device 10 is not limited, but in the embodiment, a wafer unit 2 on which a wafer 1 with a diameter of 300 mm is mounted is shown as an example, as shown in Figure 12.

As shown in FIG. 2, the workpiece dividing device 10 is a device that divides a wafer 1 on which planned dividing lines 5 are formed into individual chips 6 along the planned dividing lines 5. A plurality of planned dividing lines 5 are formed in the X direction and the Y direction which are perpendicular to each other. In the embodiment, a wafer 1 having 300 planned dividing lines 5 parallel to the X direction and 300 planned dividing lines 5 parallel to the Y direction, each spaced equally apart, i.e., a wafer 1 to be divided into chips 6 with a chip size of 1 mm, is illustrated.

As shown in Figures 1 and 2, the wafer 1 is attached to the center of a dicing tape 3 whose outer periphery is fixed to a frame 4. The dicing tape 3 has a central region 3A that is circular in plan view to which the wafer 1 is attached, and an annular region 3B that is doughnut-shaped in plan view between the outer edge of the central region 3A (the outer edge of the wafer 1) and the inner edge of the frame 4.

The thickness of the wafer 1 is, for example, about 50 μm. The dicing tape 3 is, for example, a PVC (polyvinyl chloride) tape. The wafer 1 may be attached to the dicing tape 3 via a film-like adhesive such as DAF (Die Attach Film). The film-like adhesive may be, for example, a PO (polyolefin)-based adhesive.

The workpiece dividing device 10 has a fixing part 7 (see Figures 13 and 14) that fixes the frame 4, an expansion ring 14 that abuts against the annular region 3B of the dicing tape 3 from below and presses and expands the dicing tape 3, and an expansion retaining ring (also called a sub-ring) 18 that retains the expanded state of the dicing tape 3 expanded by the expansion ring 14.

As shown in FIG. 1, the work division device 10 includes a cooling chamber 16 that surrounds the fixing portion 7, the expand ring 14, and the expansion retaining ring 18. The work division device 10 further includes a cold air supply unit 24 having a nozzle 22 that supplies subzero cold air 20 to the cooling chamber 16, and a halogen lamp 28 that is a heating unit that heats the fitting portion 26 of the expansion retaining ring 18 that has been cooled by the cold air 20 before the fitting portion 26 is fitted to the surface 4A of the frame 4. The halogen lamp 28 is also surrounded by the cooling chamber 16. The cooling unit is composed of the cooling chamber 16 and the cold air supply unit 24. Cold air 20 is supplied to the interior space 17 of the cooling chamber 16, which is the space that includes the expand ring 14 and the expansion retaining ring 18.

The fixing part 7 is disposed on the same side of the dicing tape 3 as the attachment surface of the wafer 1, and the frame 4 is detachably fixed to its underside 7A. The fixing part 7 is also disposed at a position spaced outward from the annular region 3B in the in-plane direction of the dicing tape 3 indicated by the arrow A so as not to come into contact with the annular region 3B expanded by the expand ring 14.

As shown in FIG. 2, the shape of the fixing part 7 is a ring having an opening 7B with a diameter of, for example, 361 mm, which is larger than the inner diameter (350 mm) of the frame 4, but the shape is not particularly limited. The fixing part 7 can be, for example, a rectangular plate material having an opening 7B, or a fixing part consisting of multiple fixing members arranged at a predetermined interval along the outer periphery of the frame 4. The inscribed circles of these fixing members are set equal to the diameter of the opening 7B.

The expand ring 14 is disposed on the back side of the dicing tape 3 opposite to the attachment surface of the wafer 1, and is formed in a ring shape with an expansion opening (opening) 14A that is smaller than the inner diameter (350 mm) of the frame 4 and larger than the outer diameter (300 mm) of the wafer 1. The expand ring 14 is disposed so as to be movable in a direction approaching the dicing tape 3 relatively. Specifically, the expand ring 14 is disposed so as to be movable in the vertical direction between an expansion position (position shown by the two-dot chain line in FIG. 1) where the expand ring 14 presses the back side of the annular region 3B of the dicing tape 3 to expand the annular region 3B, and a retracted position (position shown by the solid line in FIG. 1) where the expand ring 14 is retracted downward from the expansion position.

The workpiece dividing device 10 is also provided with an expand ring moving mechanism 30 that moves the expand ring 14 up and down between the expanded position and the retracted position. A feed screw device is shown as an example of the expand ring moving mechanism 30, but an actuator such as an air cylinder device can be used instead. When the expand ring 14 located in the retracted position is moved toward the expanded position by the expand ring moving mechanism 30, the expand ring 14 is moved upward in the direction of arrow B toward the annular region 3B. As a result, the back surface of the annular region 3B is pressed against the expand ring 14 and radially expanded. Note that the expand ring 14 may be fixed and the wafer unit 2 moved downward in the direction of arrow C to press the annular region 3B with the expand ring 14.

Figure 3 is a longitudinal cross-sectional view of the main part of the wafer unit 2, showing the shape of the annular region 3B in the middle of being expanded by the expand ring 14. As will be described later, prior to the expansion of the annular region 3B by the expand ring 14, the interior space 17 of the cooling chamber 16 is cooled by cold air 20, for example, at -20 to -40°C, supplied from the nozzle 22 to the interior space 17. As a result, the dicing tape 3 is made brittle and the spring constant of the dicing tape 3 is made larger than that at room temperature. In this state, the annular region 3B of the dicing tape 3 is expanded by the expand ring 14, so that even if the chip size is small, it is possible to divide it into individual chips. The temperature of the annular region 3B cooled by the cold air 20 may be measured by a radiation thermometer (not shown). In addition, the temperature change data of the annular region 3B based on the temperature of the cold air 20 and the supply time of the cold air 20 may be actually measured in advance, and the supply time of the cold air 20 may be controlled based on this temperature change data.

The nozzle 22 shown in FIG. 1 is disposed inside the cooling chamber 16, facing the annular region 3B of the dicing tape 3. This allows the annular region 3B to be efficiently cooled by the cold air 20. The cold air supply unit 24 also includes a heat exchanger that cools the sucked outside air to below zero, and the cold air 20 cooled by the heat exchanger is supplied to the nozzle 22 via the piping 25. Note that while the cold air supply unit 24 is disposed outside the cooling chamber 16 in FIG. 1, it may also be disposed inside the cooling chamber 16. In this case, the cold air supply unit 24 cools the cooled indoor air in the indoor space 17, thereby reducing the load on the heat exchanger.

1, the expansion retaining ring 18 that retains the expanded state of the dicing tape 3 is disposed on the back side of the dicing tape 3 opposite to the surface to which the wafer 1 is attached. The expansion retaining ring 18 has a main ring 32 whose outer diameter is smaller than the inner diameter (350 mm) of the frame 4 and whose inner diameter is larger than the outer diameter of the expand ring 14, and an elastically deformable ring-shaped fitting portion 26 that is attached to the outer periphery of the main ring 32 and whose outer diameter (351.3 mm) is larger than the inner diameter (350 mm) of the frame 4. PP (polypropylene), which becomes brittle in a sub-zero environment, is exemplified as a material for the fitting portion 26. The material for the fitting portion 26 is not limited to PP, but is preferably a material that becomes brittle at least below zero and has elasticity in a room temperature environment.

As shown in FIG. 1, the halogen lamp 28 that heats the fitting portion 26 is positioned so as to surround the fitting portion 26 of the expansion retaining ring 18, which is positioned in the standby position shown by the solid line. The halogen lamp 28 is configured in a ring shape as shown in FIG. 2, but the shape is not limited to a ring shape. For example, a rod-shaped halogen lamp may be used. In this case, the fitting portion 26 may be surrounded by multiple rod-shaped halogen lamps.

The halogen lamp 28 is lit by power supplied from the halogen lamp power supply 34 and dissipates heat. In addition, a reflector 36 is arranged close to the halogen lamp 28 on the outside of the halogen lamp 28. As a result, the fitting portion 26 is heated to a temperature above room temperature by direct heat from the halogen lamp 28 and reflected heat reflected by the reflector 36. The expansion retaining ring 18 is raised from the standby position after the temperature of the fitting portion 26 is raised to a temperature above room temperature, for example, a temperature above 20°C, and maintains the expanded state of the dicing tape 3. The temperature of the fitting portion 26 heated by the halogen lamp 28 may be measured by a radiation thermometer (not shown). In addition, the temperature change data of the fitting portion 26 based on the lighting time of the halogen lamp 28 may be actually measured in advance, and the lighting time of the halogen lamp 28 may be controlled based on the temperature change data.

Figure 4 is a vertical cross-sectional view of the dicing tape 3 in an expanded state maintained by the expansion retaining ring 18. Figure 5 is an enlarged cross-sectional view of a main portion of Figure 4.

As shown in Figures 4 and 5, the fitting portion 26 of the expansion retaining ring 18 fits onto the surface 4A of the frame 4 through the annular region 3B of the dicing tape 3 at the fitting position shown by the solid line. This allows the expansion state of the dicing tape 3 to be maintained by the expansion retaining ring 18.

Before expansion and retention, the expansion retaining ring 18 is disposed in a standby position (position shown by a solid line in FIG. 1) below the engagement position shown by the solid lines in FIG. 4 and FIG. 5, and is moved upward from the standby position to the engagement position by the expansion retaining ring moving mechanism 38 during expansion and retention. A feed screw device is shown as an example of the expansion retaining ring moving mechanism 38, but an actuator such as an air cylinder device can be used instead.

When the expansion retaining ring 18 is raised by the expansion retaining ring moving mechanism 38, the fitting portion 26, which has been heated by the halogen lamp 28 to a temperature above room temperature, comes into contact with the lower surface of the frame 4. At this time, the fitting portion 26 has recovered from a brittle state to an elastic state, so that it rises while being elastically deformed as it is pushed by the inner peripheral surface of the frame 4 due to the continued upward movement of the expansion retaining ring 18. Then, the rise of the expansion retaining ring 18 is stopped at the position where the fitting portion 26 has passed the inner peripheral surface of the frame 4. As a result, the fitting portion 26, which has been restored to an elastic state, is fitted to the surface 4A of the frame 4 at the fitting position as shown in Figures 4 and 5. Note that the expansion retaining ring 18 may be fixed and the dicing tape 3 side may be moved in a direction approaching the expansion retaining ring 18. In other words, when fitting the fitting portion 26 to the surface 4A of the frame 4, the expansion retaining ring 18 may be moved in a direction approaching the dicing tape 3 relatively.

The operation of the expand ring moving mechanism 30 that drives the expand ring 14, the expansion retaining ring moving mechanism 38 that drives the expansion retaining ring 18, the cold air supply unit 24, and the halogen lamp power supply 34 is controlled by the control unit 40 that overall controls the work division device 10, as shown in the block diagram of the control system in Figure 6.

Next, the work division method will be specifically explained according to the flowchart in FIG. 7 and the operation explanatory diagrams of the work division device 10 shown in FIGS. 8(A)-(D) and 9(A)-(D).

First, in the placement process of step S100 in FIG. 7, as shown in FIG. 8(A), the expand ring 14 is placed in the retracted position by the expand ring moving mechanism 30, and the expansion retaining ring 18 is placed in the standby position by the expansion retaining ring moving mechanism 38.

Next, in the fixing process of step S110 in FIG. 7, the frame 4 of the wafer unit 2 is fixed to the fixing portion 7 as shown in FIG. 8 (B).

Next, in the cold air cooling process of step S130 in FIG. 7, as shown in FIG. 8(C), cold air 20 is supplied from nozzle 22 to interior space 17 (see FIG. 1) of cooling chamber 16, and annular region 3B of dicing tape 3 is cooled to below zero (e.g., -20 to -40°C). This makes annular region 3B of dicing tape 3 brittle. Note that the temperature of cold air 20 is not limited to below zero, and may be any temperature below the temperature at which dicing tape 3 becomes brittle.

Next, in the expansion start process of step S140 in FIG. 7, as shown in FIG. 8(D), the expand ring 14 is moved upward in the direction of arrow B by the expand ring moving mechanism 30 from the retracted position in FIG. 8(A) to the expanded position, and the expansion of the entire area of the embrittled annular region 3B begins. Note that in the expansion start process, the state in which the cold air 20 is sprayed from the nozzle 22 may be maintained, and in the cold air cooling process of step S130, if the annular region 3B is sufficiently cooled, the spraying of the cold air 20 from the nozzle 22 may be stopped.

Next, in the division process of step S150 in FIG. 7, the upward movement of the expand ring 14 is continued as shown in FIG. 9(A), thereby dividing the wafer 1 into individual chips 6. After this, as shown in FIG. 9(B), when the expand ring 14 reaches the expanded position, the upward movement of the expand ring 14 is stopped.

In the division process of step S150, the tension of the spring constant of the annular region 3B, which has a larger spring constant than at room temperature, is applied to the wafer 1. This allows the annular region 3B to apply to the wafer 1 a tension sufficient to divide the wafer into individual chips 6, even if the chip size is small (1 mm). Therefore, the work division device 10 can solve the problem of non-division of the planned division line, which occurs when the chip size is small (1 mm).

Next, in the heating process of step S160 in FIG. 7, as shown in FIG. 9(B), the halogen lamp 28 is turned on to heat the fitting portion 26 of the expansion retaining ring 18 to a temperature above room temperature. The heating process of step S160 may be performed during the division process of step S150, or after the division process of step S150 is completed. The temperature to which the fitting portion 26 is heated by the halogen lamp 28 is not limited to a temperature above room temperature, but may be any temperature above the temperature of the cold air 20 at which the fitting portion 26, which has been made brittle by the cold air 20, recovers to an elastic state.

Next, in the expanded state maintaining process of step S170 in FIG. 7, the expansion retaining ring 18 is raised from the standby position toward the mating position by the expansion retaining ring moving mechanism 38, as shown in FIG. 9 (C), and the mating portion 26, whose elastic state has been restored, is mated with the surface 4A of the frame 4 at the mating position to maintain the expanded state of the dicing tape 3.

Next, in the expand ring retraction process of step S180 in FIG. 7, the expand ring 14 is moved downward by the expand ring moving mechanism 30 to the retracted position as shown in FIG. 9 (D), and placed in the retracted position. At this time, the expansion of the dicing tape 3 by the expand ring 14 is released, but since the fitting portion 26 of the expansion retaining ring 18 is fitted to the surface 4A of the frame 4, the expanded state is maintained without loosening. This makes it possible to prevent contact between the chips 6 caused by loosening of the expanded dicing tape 3, and therefore prevents deterioration of the quality of the chips 6.

As described above, the workpiece dividing method using the workpiece dividing device 10 of the embodiment includes the cold air cooling process of step S130, which makes it possible to make the dicing tape 3 brittle and increase the spring constant of the dicing tape 3. This makes it possible to solve the problem of non-division along the intended dividing line that occurs when the chip size is small.

In addition, according to the workpiece dividing method using the workpiece dividing device 10 of the embodiment, since it includes the heating step of step S160, it is possible to restore the fitting portion 26, which has been cooled to a brittle state in the cold air cooling step of step S130, to an elastic state. After this, since it includes the expanded state maintaining step of step S170, it is possible to fit the fitting portion 26, which has been restored to its elastic state, onto the surface 4A of the frame 4. This makes it possible to solve the problem of deterioration in chip quality caused by contact between the chips after division.

In the above embodiment, the halogen lamp 28 is exemplified as the heating unit, but this is not limited thereto. For example, the heating unit may be a far-infrared lamp, an infrared lamp, a ceramic heater, a carbon heater, a hot air heater, or a contact heater. With these heating units, the embrittled fitting portion 26 can be heated and restored to an elastic state even inside the cooling chamber 16, which is in a low-temperature environment.

As shown in FIG. 10, an air supply unit 44 may be provided as the heating unit to supply room temperature air 42 to the fitting portion 26 of the expansion retaining ring 18. With this heating unit, the fitting portion 26 can be restored from a brittle state to an elastic state by supplying room temperature air 42 even inside the cooling chamber 16, which is a low-temperature environment.

In the present invention, the fitting portion 26 of the expansion retaining ring 18 is heated by the heating portion in the interior space 17 of the cooling chamber 16 in a low-temperature environment to restore the elastic state, and then the expansion retaining ring 18 maintains the expanded state of the dicing tape 3. However, the fitting portion 26 can also be fitted to the surface 4A of the frame 4 without using the heating portion. For example, the standby position of the expansion retaining ring 18 is set outside the cooling chamber 16 in a room temperature environment, and a door is provided in the cooling chamber 16 for inserting and removing the expansion retaining ring 18. Then, when maintaining the expanded state of the dicing tape 3, the door is opened and the expansion retaining ring 18 is moved from outside the cooling chamber 16 to the interior space 17, and the fitting portion 26 in the room temperature state is fitted to the surface 4A of the frame 4. Even with this configuration, the problem of non-separation of the planned division line that occurs when the chip size is small and the problem of deterioration of the quality of the chip due to contact between the chips after division can be simultaneously solved.

1...wafer, 2...wafer unit, 3...dicing tape, 3A...central region, 3B...annular region, 3C...fixed region, 4...frame, 5...planned division line, 6...chip, 7...fixed section, 8...expanding ring, 10...work division device, 14...expanding ring, 16...cooling chamber, 17...indoor space, 18...expanding retaining ring, 20...cold air, 22...nozzle, 24...cold air supply section, 25...piping, 26...fitting section, 28...halogen lamp, 30...expanding ring moving mechanism, 32...main ring, 34...halogen lamp power supply, 36...reflector, 38...expanding retaining ring moving mechanism, 40...control section, 42...room temperature air, 44...air supply section

Claims (8)

A workpiece dividing device for dividing a workpiece mounted on a frame via a dicing tape into individual chips along a division line,
an expand ring that expands the dicing tape;
an expansion retaining ring formed in a ring shape having an elastically deformable fitting portion, the fitting portion being fitted to a surface of the frame when the dicing tape is in a state where it is expanded by the expanding ring, thereby retaining the expanded state of the dicing tape;
A cooling section that cools a space including the expand ring and the expansion retaining ring;
a heating unit that heats the fitting portion of the expansion retaining ring that has been cooled by the cooling unit before the fitting portion of the expansion retaining ring is fitted to the surface of the frame;
A heating control unit that controls a heating time of the heating unit based on a predetermined correspondence relationship between the heating time of the heating unit and the temperature of the mating unit;
A workpiece dividing device comprising: The cooling unit supplies cold air having a temperature at which the dicing tape becomes brittle to the space,
The heating unit heats the fitting portion to a temperature exceeding the temperature of the cold air to make the fitting portion elastic.
The workpiece dividing device according to claim 1 . The workpiece dividing device according to claim 1 or 2, wherein the heating unit is a heat supply unit that supplies heat above room temperature to the fitting unit. The workpiece dividing device according to claim 1 or 2, wherein the heating unit is an air supply unit that supplies room temperature air to the fitting unit. A workpiece dividing method for dividing a workpiece mounted on a frame via a dicing tape into individual chips along a planned dividing line, comprising:
a cooling step of cooling the dicing tape with cold air;
an expanding step of expanding the dicing tape by an expanding ring;
a heating step of heating an elastically deformable fitting portion formed on an outer periphery of the expansion retaining ring;
an expansion state maintaining step of maintaining the expanded state of the dicing tape expanded by the expansion step by fitting the heated fitting portion of the expansion holding ring to a surface of the frame;
a heating control step of controlling a heating time of the heating step based on a predetermined correspondence relationship between the heating time of the heating step and the temperature of the mating portion;
A workpiece dividing method comprising: The cooling step includes supplying the cold air to the dicing tape at a temperature at which the dicing tape becomes brittle,
The heating step heats the fitting portion at a temperature exceeding the temperature of the cold air to make the fitting portion elastic.
The workpiece dividing method according to claim 5. The workpiece dividing method according to claim 5 or 6, wherein the heating step supplies heat above room temperature to the fitting portion. The workpiece dividing method according to claim 5 or 6, wherein the heating step supplies room temperature air to the fitting portion.

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