Workpiece splitting device

Abstract

This invention provides a workpiece splitting device that eliminates the problem of chip quality degradation caused by contact between chips after splitting. [Solution] The workpiece splitting device includes an expand ring 14 for expanding the dicing tape 3, an expansion holding ring 18 formed in a ring shape having an elastically deformable fitting portion 26, which holds the expanded state of the dicing tape 3 by fitting the fitting portion 26 to the surface of the frame 4 when the dicing tape 3 is expanded by the expand ring 14, and a heating unit 28 that heats the fitting portion 26 of the expansion holding ring 18 before the fitting portion 26 of the expansion holding ring 18 is fitted to the surface of the frame 4.

Description

Technical Field

[0001] The present invention relates to a work dividing device and a work dividing method, and particularly to a work dividing device and a work dividing method for dividing a work such as a semiconductor wafer into individual chips along a planned dividing line.

Background Art

[0002] Conventionally, in the manufacture of semiconductor chips (hereinafter referred to as chips), a semiconductor wafer (hereinafter referred to as a wafer) in which a planned dividing line is previously formed inside by a half cut using a dicing blade or formation of a modified region by laser irradiation is divided into individual chips along the planned dividing line. A work dividing device is known (see Patent Document 1, etc.).

[0003] FIG. 11 is an explanatory view of a wafer unit 2 to which a disk-shaped wafer 1 to be divided by a work dividing device is attached. FIG. 11(A) is a perspective view of the wafer unit 2, and FIG. 11(B) is a longitudinal sectional view of the wafer unit 2.

[0004] The wafer 1 is attached to the center of a dicing tape (also referred to as an expansion tape or an adhesive sheet) 3 having a thickness of about 100 μm with an adhesive layer formed on one side. The outer peripheral portion of the dicing tape 3 is fixed to a rigid ring-shaped frame 4.

[0005] In the work dividing device, the frame 4 of the wafer unit 2 is brought into contact with a fixing portion (also referred to as a frame fixing mechanism) 7 shown by a two-dot chain line and fixed. Thereafter, an expand ring (also referred to as 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 and radially expanded. The tension of the dicing tape 3 generated at this time is applied to the planned dividing line 5 of the wafer 1, whereby the wafer 1 is divided into individual chips 6.

[0006] In this specification, the circular region of the dicing tape 3 to which the wafer 1 is attached is referred to as the central region 3A, the donut-shaped region 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 is referred to as the annular region 3B, and the outermost donut-shaped region in plan view that is fixed to the frame 4 is referred to as the fixed region 3C. The annular region 3B is the region that is pressed and expanded by the expanding ring 8.

[0007] In a workpiece splitting apparatus, it is known that the force required to split the wafer 1, that is, the tension that must be generated in the annular region 3B to split the wafer 1, must increase as the number of planned splitting lines 5 increases. Regarding the number of planned splitting lines 5, for example, if the wafer 1 has a diameter of 300 mm and a chip size of 5 mm, approximately 120 planned splitting lines 5 (60 in each of the X and Y directions) are formed, and if the chip size is 1 mm, approximately 600 planned splitting lines 5 are formed. Therefore, the tension that must be generated in the annular region 3B must increase as the chip size decreases.

[0008] Incidentally, the inner diameter (the diameter of the inner edge of the frame) of the frame 4 on which the 300mm diameter wafer 1 is mounted is defined as 350mm according to the SEMI standard (G74-0699 Specification for Tape Frames for 300mm Wafers). According to this standard, as shown in the longitudinal section of the wafer unit 2 in Figure 12, there is an annular region 3B with a width of 25mm between the outer edge of the wafer 1 and the inner edge of the frame 4. Furthermore, as shown in the longitudinal section of the main part of the workpiece splitting device in Figures 13(A) and (B), the fixing part 7 that secures the frame 4 is positioned outward from the annular region 3B in the in-plane direction of the dicing tape 3 indicated by arrow A, so as not to come into contact with the annular region 3B which is expanded by the expanding ring 8.

[0009] Here, the force that divides the wafer 1, generated by the upward movement of the expanding 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.

[0010] As shown in the operation diagrams of the workpiece splitting device in Figures 14(A) to (E), the expand ring 8 comes into contact with the annular region 3B of the dicing tape 3, and when the dicing tape 3 begins to expand due to the upward movement of the expand ring 8 (Figure 14(A)), the annular region 3B with 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 splitting of the wafer 1 into chips 6 begins (Figure 14(C)). Once the wafer 1 is split 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)).

[0011] In conventional workpiece splitting devices, when the chip size of a 300 mm diameter wafer 1 was 5 mm or larger, the tension generated in the annular region 3B allowed for the individual chips 6 to be split without any problems. However, with the miniaturization of circuit patterns formed on wafer 1, chips smaller than 1 mm have appeared. In this case, the number of planned splitting lines 5 for splitting wafer 1 increases, resulting in a greater force required to split wafer 1, sometimes exceeding the tension generated by the expansion of the annular region 3B. Consequently, as shown in the longitudinal cross-sectional view of the wafer unit 2 in Figure 15, even after the expansion operation by the expander ring 8 is completed, a problem arises where some of the planned splitting lines 5 formed on wafer 1 remain undivided.

[0012] This problem of undivided planned division lines 5 cannot be resolved by increasing the expansion amount or expansion speed of the dicing tape 3. For example, if the expansion amount of the dicing tape 3 is increased, the annular region 3B will begin 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, the tension required to divide the wafer 1 into individual chips 6 does not occur in the region of the annular region 3B beyond the elastic deformation. On the other hand, even if the expansion speed of the dicing tape 3 is increased, a portion of the annular region 3B will begin to undergo plastic deformation, so the tension required to divide the wafer 1 into individual chips 6 does not occur. This is because the frequency response of the dicing tape 3 is low, so force is not transmitted to the entire dicing tape 3 without time lag.

[0013] Therefore, as an example of a device that solves the above-mentioned problems, a tape expansion device (workpiece splitting device) equipped with a cold air supply means is disclosed in Patent Document 2. According to Patent Document 2, the dicing tape is cooled by operating the cold air supply means to supply cold air into the processing space and cooling the processing space to, for example, below zero.

[0014] As described in Patent Document 2, by cooling the dicing tape, the spring constant of the dicing tape can be increased, allowing the dicing tape to expand. This makes it possible to increase the tension generated in the annular region 3B shown in Figure 12 compared to an uncooled dicing tape, thus enabling the individual chips to be separated even when the chip size is small.

[0015] On the other hand, in the field of workpiece splitting equipment, it is also required to prevent the deterioration of chip quality caused by contact between chips after splitting by maintaining the expanded state of the dicing tape expanded by the expander ring.

[0016] As a workpiece splitting device that satisfies this requirement, a workpiece splitting device equipped with a sub-ring is disclosed in Patent Document 3. The sub-ring in Patent Document 3 has the function of holding the dicing tape, which has been expanded by the expander ring, in an expanded state, and is configured to have a larger diameter than the inner diameter of the frame. The sub-ring rises from the back side of the dicing tape toward the dicing tape. Immediately after the sub-ring passes through the frame, a fitting portion (also called a lip) provided on the outer circumference of the sub-ring is inserted between the outer circumference of the dicing tape and the surface of the frame. As a result, even after the expansion of the dicing tape by the expander ring is completed, the expanded state of the dicing tape is maintained. By maintaining the expanded state of the dicing tape in this way, slack in the dicing tape can be prevented, and thus the deterioration of chip quality caused by contact between chips can be prevented. [Prior art documents] [Patent Documents]

[0017] [Patent Document 1] Japanese Patent Publication No. 2016-149581 [Patent Document 2] Japanese Patent Publication No. 2016-12585 [Patent Document 3] Japanese Patent Publication No. 2013-51368 [Overview of the project] [Problems that the invention aims to solve]

[0018] However, the workpiece splitting devices described in Patent Documents 1 and 2 do not have a sub-ring like the one in Patent Document 3, which may lead to problems such as a decrease in chip quality due to contact between chips after splitting.

[0019] On the other hand, if the sub-ring described in Patent Document 3 is mounted on the workpiece splitting device described in Patent Document 2, which cools the dicing tape with cold air, a problem arises in which the resin fitting portion of the sub-ring hardens and becomes brittle in the low-temperature environment. Due to this problem, there is a risk that the fitting portion of the sub-ring may break when it is inserted between the outer circumference of the dicing tape and the surface of the frame. Therefore, it is difficult to mount the sub-ring described in Patent Document 3 on the workpiece splitting device described in Patent Document 2.

[0020] Thus, conventional workpiece splitting devices have not been able to solve the problem of undivided sections in the planned splitting line that occurs when chip sizes are small, while also solving the problem of chip quality degradation caused by contact between split chips. There has been a desire to realize such a device.

[0021] This invention has been made in view of the above problems, and aims to provide a workpiece splitting apparatus and workpiece splitting method that can simultaneously solve the problem of undivided lines on the planned splitting line that occurs when the chip size is small, and the problem of deterioration of chip quality caused by contact between chips after splitting. [Means for solving the problem]

[0022] In order to achieve the object of the present invention, the work dividing device of the present invention is a work dividing device that divides a work attached to a dicing tape into individual chips along a planned division line, wherein the outer peripheral portion of the dicing tape is fixed to a ring-shaped frame having an inner diameter larger than the outer diameter of the work. An expandable ring formed in a ring shape that is disposed on the back surface side opposite to the surface of the dicing tape to which the work is attached, has an opening smaller than the inner diameter of the frame and larger than the outer diameter of the work, and presses and expands the dicing tape by moving in a direction relatively approaching the dicing tape; An expandable holding ring formed in a ring shape that is disposed on the back surface side opposite to the surface of the dicing tape to which the work is attached and has an elastically deformable fitting portion larger than the inner diameter of the frame. In a state where the dicing tape is expanded by the expandable ring, the fitting portion is fitted to the surface of the frame to hold the expanded state of the dicing tape; A cooling unit that cools the space including the expandable ring and the expandable holding ring; A heating unit that heats the fitting portion cooled by the cooling unit before the fitting portion of the expandable holding ring is fitted to the surface of the frame.

[0023] According to the work dividing device of the present invention, the dicing tape is cooled by the cold air of the cooling unit, and the dicing tape is expanded by the expandable ring in a state where the spring constant of the dicing tape is increased. Thereby, according to the work dividing device of the present invention, even when the chip size is a small chip, it can be divided into individual chips. At this time, since the fitting portion of the expandable holding ring is cooled by the cold air and the property changes from the elastic state to the brittle state, before fitting this fitting portion to the surface of the frame, the fitting portion is heated by the heating unit. As a result, the fitting portion is restored from the brittle state to the elastic state, and thereafter, it is fitted to the surface of the frame to maintain the expanded state of the dicing tape.

[0024] As described above, according to the workpiece dividing apparatus of the present invention, it is possible to simultaneously solve the problem of undivided division planned lines that occur when the chip size is a small chip and the problem of deterioration in chip quality due to contact between chips after division.

[0025] In one aspect of the workpiece dividing apparatus of the present invention, it is preferable that the cooling unit supplies cold air at a temperature at which the dicing tape becomes brittle into the space, and the heating unit heats the fitting portion at a temperature exceeding the temperature of the cold air to make the fitting portion elastic. Thereby, the spring constant of the dicing tape increases due to the cold air, and the fitting portion returns from the brittle state to the elastic state.

[0026] In one aspect of the workpiece dividing apparatus of the present invention, it is preferable that the heating unit is a heat supply unit that supplies heat exceeding room temperature to the fitting portion. Thereby, the fitting portion surely returns from the brittle state to the elastic state.

[0027] In one aspect of the workpiece dividing apparatus of the present invention, it is preferable that the heating unit is an air supply unit that supplies room temperature air to the fitting portion. Thereby, the fitting portion surely returns from the brittle state to the elastic state.

[0028] The present invention provides a workpiece division method for achieving the objectives of the present invention, 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 workpiece, and the workpiece attached to the dicing tape is divided into individual chips along a planned division line, comprising: a cooling step of cooling the dicing tape with cold air; an expansion step of expanding the dicing tape by moving an expand ring, which is positioned on the back side of the dicing tape opposite to the surface on which the workpiece is attached, in a direction toward relative to the dicing tape, thereby pressing the annular region of the dicing tape between the outer edge of the workpiece and the inner edge of the frame with the expand ring; a heating step of heating an elastically deformable fitting portion formed on the outer periphery of an expansion holding ring, which is positioned on the back side of the dicing tape opposite to the surface on which the workpiece is attached; and an expanded state holding step of holding the dicing tape expanded by the expansion step by moving the expansion holding ring toward relative to the dicing tape, thereby fitting the heated fitting portion to the surface of the frame.

[0029] The workpiece division method of the present invention simultaneously solves the problem of undivided lines in the planned division process, which occurs when the chip size is small, and the problem of chip quality degradation caused by contact between divided chips.

[0030] In one aspect of the workpiece splitting method of the present invention, it is preferable that the cooling step involves supplying cold air to the dicing tape at a temperature at which the dicing tape becomes brittle, and the heating step involves heating the mating portion at a temperature exceeding the temperature of the cold air to make 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.

[0031] In one aspect of the workpiece splitting method of the present invention, it is preferable that the heating step supplies heat above room temperature to the fitting portion. This ensures that the fitting portion recovers from an embrittlement state to an elastic state.

[0032] In one aspect of the workpiece splitting method of the present invention, it is preferable that the heating step involves supplying room-temperature air to the fitting portion. This ensures that the fitting portion recovers from an embrittlement state to an elastic state. [Effects of the Invention]

[0033] According to the present invention, it is possible to simultaneously resolve the problem of undivided lines on the planned division lines that occur when the chip size is small, and the problem of chip quality degradation caused by contact between divided chips. [Brief explanation of the drawing]

[0034] [Figure 1] Structural diagram of the main part of the splitting stage of the workpiece splitting device of the embodiment [Figure 2] Enlarged perspective view of the main part of the dividing stage shown in Figure 1. [Figure 3] A longitudinal cross-sectional view of the main part of a wafer unit showing the shape of the annular region during expansion. [Figure 4] A longitudinal cross-sectional view showing the expanded state of the dicing tape by the expansion retaining ring. [Figure 5] Figure 4: Enlarged cross-sectional view of the main part [Figure 6] Block diagram showing the control system of a workpiece splitting device. [Figure 7] A flowchart showing an example of a wafer splitting method. [Figure 8] Operational diagram of the workpiece splitting device [Figure 9] Operational diagram of the workpiece splitting device [Figure 10] An explanatory diagram showing an air supply unit that supplies ambient temperature air as the heating element. [Figure 11] Diagram illustrating a wafer unit with a wafer attached. [Figure 12] Longitudinal cross-section of a wafer unit [Figure 13] Side view of the main components of the workpiece splitting device. [Figure 14] Operation diagram of the workpiece splitting device [Figure 15] Longitudinal cross-sectional view of a wafer unit after the wafer has been divided. [Modes for carrying out the invention]

[0035] Preferred embodiments of the workpiece splitting apparatus and workpiece splitting method according to the present invention will be described in detail below 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.

[0036] Figure 1 is a longitudinal cross-sectional view of the main part of the splitting stage provided in the workpiece splitting apparatus 10 according to the embodiment, and Figure 2 is an enlarged perspective view of the main part of the splitting stage. Although the size of the wafer unit to be split by the workpiece splitting apparatus 10 is not limited, in this embodiment, a wafer unit 2 on which a wafer 1 with a diameter of 300 mm shown in Figure 12 is mounted is used as an example.

[0037] As shown in Figure 2, the workpiece splitting apparatus 10 is a device that splits a wafer 1 on which splitting lines 5 are formed into individual chips 6 along the splitting lines 5. Multiple splitting lines 5 are formed in mutually orthogonal X and Y directions. In this embodiment, an example is given of a wafer 1 in which the number of splitting lines 5 parallel to the X direction and the number of splitting lines 5 parallel to the Y direction are both 300 and the spacing between them is equal, i.e., a wafer 1 that is split into chips 6 with a chip size of 1 mm.

[0038] As shown in Figures 1 and 2, 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 circular central region 3A in plan view to which wafer 1 is attached, and a donut-shaped annular region 3B in plan view between the outer edge of the central region 3A (the outer edge of wafer 1) and the inner edge of the frame 4.

[0039] The thickness of wafer 1 is, for example, about 50 μm. The dicing tape 3 is, for example, a PVC (polyvinyl chloride) tape. Alternatively, wafer 1 may be attached to the dicing tape 3 via a film-type adhesive such as DAF (Die Attach Film). For example, a PO (polyolefin)-based film-type adhesive can be used.

[0040] The workpiece splitting device 10 includes a fixing part 7 (see Figures 13 and 14) for fixing the frame 4, an expand ring 14 that contacts the annular region 3B of the dicing tape 3 from below to press and expand the dicing tape 3, and an expansion holding ring (also called a sub-ring) 18 that maintains the expanded state of the dicing tape 3 expanded by the expand ring 14.

[0041] Furthermore, as shown in Figure 1, the workpiece splitting device 10 includes a cooling chamber 16 surrounding the fixing part 7, the expand ring 14, and the expanded retaining ring 18. In addition, the workpiece splitting device 10 includes a cold air supply unit 24 equipped with a nozzle 22 that supplies sub-zero cold air 20 to the cooling chamber 16, and a halogen lamp 28 which is a heating unit that heats the fitted part 26 of the expanded retaining ring 18, which has been cooled by the cold air 20, before the fitted part 26 of the expanded retaining ring 18 fits onto the surface 4A of the frame 4. This halogen lamp 28 is also surrounded by the cooling chamber 16. The cooling unit is formed by 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 including the expand ring 14 and the expanded retaining ring 18.

[0042] The fixing portion 7 is positioned on the same side of the dicing tape 3 as the surface to which the wafer 1 is attached, and the frame 4 is detachably fixed to its lower surface 7A. Furthermore, the fixing portion 7 is positioned so as not to come into contact with the annular portion 3B that is expanded by the expanding ring 14, by being spaced outward from the annular portion 3B in the in-plane direction of the dicing tape 3 indicated by arrow A.

[0043] As shown in Figure 2, the shape of the fixing part 7 is ring-shaped with an opening 7B that is larger than the inner diameter of the frame 4 (350 mm), for example, a diameter of 361 mm, but its shape is not particularly limited. As an example of the fixing part 7, a rectangular plate-like material having an opening 7B can be exemplified, or a fixing part consisting of a plurality of fixing members arranged at predetermined intervals along the outer circumference of the frame 4 can be exemplified. The inscribed circles of these fixing members are set to be equal to the diameter of the opening 7B.

[0044] The expanding ring 14 is positioned on the back side of the dicing tape 3 opposite to the surface to which the wafer 1 is attached, and is formed in a ring shape having an expansion opening (opening) 14A that is smaller than the inner diameter of the frame 4 (350 mm) and larger than the outer diameter of the wafer 1 (300 mm). The expanding ring 14 is positioned to be movable in a direction that moves relatively closer to the dicing tape 3. Specifically, the expanding ring 14 is positioned to be movable vertically between an expansion position (shown by the dashed line in Figure 1) in which it presses the back side of the annular region 3B of the dicing tape 3 to expand the annular region 3B, and a retracted position (shown by the solid line in Figure 1) which is retracted downward from the expansion position.

[0045] Furthermore, the workpiece splitting device 10 is equipped with an expander ring moving mechanism 30 that moves the expander ring 14 up and down between an expanded position and a retracted position. As an example of the expander ring moving mechanism 30, a lead screw device is shown, but an actuator such as an air cylinder device can be used instead. When the expander ring 14, which is in the retracted position, is moved toward the expanded position by the expander ring moving mechanism 30, the expander ring 14 moves 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 by the expander ring 14 and expands radially. Alternatively, the expander ring 14 may be fixed and the wafer unit 2 moved downward in the direction of arrow C, thereby pressing the annular region 3B with the expander ring 14.

[0046] 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 process of being expanded by the expander 14. As will be described later, prior to the expansion of the annular region 3B by the expander 14, the interior space 17 of the cooling chamber 16 is cooled by cold air 20, for example, -20 to -40°C, supplied from the nozzle 22. As a result, the dicing tape 3 is made brittle, and the spring constant of the dicing tape 3 becomes larger compared to when it is at room temperature. In this state, the annular region 3B of the dicing tape 3 is expanded by the expander 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 with a radiation thermometer (not shown). Alternatively, 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 measured in advance, and the supply time of the cold air 20 may be controlled based on this temperature change data.

[0047] The nozzle 22 shown in Figure 1 is positioned 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 is equipped with a heat exchanger that cools the drawn-in outside air to below freezing point, and the cold air 20 cooled by the heat exchanger is supplied to the nozzle 22 via the piping 25. In Figure 1, the cold air supply unit 24 is positioned outside the cooling chamber 16, but it may also be positioned inside the cooling chamber 16. In this case, the cold air supply unit 24 cools the cooled indoor air in the indoor space 17, thus reducing the load on the heat exchanger.

[0048] As shown in Figure 1, the expansion retaining ring 18 that holds the expanded state of the dicing tape 3 is positioned 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 of the frame 4 (350 mm) and whose inner diameter is larger than the outer diameter of the expand ring 14, and an elastically deformable ring-shaped fitting portion 26 attached to the outer circumference of the main ring 32, whose outer diameter (351.3 mm) is larger than the inner diameter of the frame 4 (350 mm). As an example of the material of the fitting portion 26, PP (polypropylene), which becomes brittle in sub-zero environments, is used. The material of the fitting portion 26 is not limited to PP, but it is preferable that it is a material that becomes brittle at least in sub-zero environments and retains elasticity in room temperature environments.

[0049] As shown in Figure 1, the halogen lamp 28 that heats the mating portion 26 is positioned to surround the mating portion 26 of the expansion retaining ring 18, which is located in the standby position shown by the solid line. This halogen lamp 28 is configured in a ring shape as shown in Figure 2, but its shape is not limited to a ring shape. For example, a rod-shaped halogen lamp may be used. In this case, the mating portion 26 can be surrounded by multiple rod-shaped halogen lamps.

[0050] The halogen lamp 28 is lit and dissipates heat using power supplied from the halogen lamp power supply 34. A reflector 36 is positioned close to the halogen lamp 28. As a result, the mating 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 rises from its standby position after the temperature of the mating portion 26 has risen above room temperature, for example, above 20°C, to maintain the expanded state of the dicing tape 3. The temperature of the mating portion 26 heated by the halogen lamp 28 may be measured using a radiation thermometer (not shown). Alternatively, temperature change data of the mating portion 26 based on the lighting time of the halogen lamp 28 may be measured in advance, and the lighting time of the halogen lamp 28 may be controlled based on that temperature change data.

[0051] Figure 4 is a longitudinal cross-sectional view showing the expanded state of the dicing tape 3 held by the expansion retaining ring 18. Figure 5 is an enlarged cross-sectional view of the main part of Figure 4.

[0052] 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 via the annular portion 3B of the dicing tape 3 at the fitting position shown by the solid line. As a result, the expanded state of the dicing tape 3 is held by the expansion retaining ring 18.

[0053] Before expansion and retention, the expansion and retention ring 18 is positioned in a standby position below the fitting position shown by the solid line in Figures 4 and 5 (the position shown by the solid line in Figure 1). When expansion and retention occurs, it is moved upward from the standby position to the fitting position by the expansion and retention ring moving mechanism 38. As an example of the expansion and retention ring moving mechanism 38, a lead screw device is shown, but an actuator such as an air cylinder device can also be used instead.

[0054] When the expansion retaining ring 18 is raised by the expansion retaining ring moving mechanism 38, the fitting portion 26, which has been heated to a temperature above room temperature by the halogen lamp 28, 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, and as the expansion retaining ring 18 continues to move upward, it is pushed against the inner circumferential surface of the frame 4, causing it to elastically deform as it rises. The upward movement of the expansion retaining ring 18 stops when the fitting portion 26 has passed the inner circumferential surface of the frame 4. As a result, the fitting portion 26, which has recovered 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. Alternatively, the expansion retaining ring 18 may be fixed, and the dicing tape 3 may be moved in a direction that brings it closer to the expansion retaining ring 18. That is, when fitting the fitting portion 26 to the surface 4A of the frame 4, the expansion retaining ring 18 should be moved in a direction that brings it relatively closer to the dicing tape 3.

[0055] The expansion ring moving mechanism 30 that drives the expansion ring 14, the expansion holding ring moving mechanism 38 that drives the expansion holding ring 18, the cold air supply unit 24, and the halogen lamp power supply 34 are all controlled by the control unit 40 that comprehensively controls the workpiece splitting device 10, as shown in the block diagram of the control system in Figure 6.

[0056] Next, the workpiece splitting method will be specifically explained according to the flowchart in Figure 7 and the operation diagrams of the workpiece splitting device 10 shown in Figures 8(A) to (D) and 9(A) to (D).

[0057] First, in the arrangement process of step S100 in Figure 7, as shown in Figure 8(A), the expand ring 14 is moved to the retracted position by the expand ring moving mechanism 30, and the expansion retaining ring 18 is moved to the standby position by the expansion retaining ring moving mechanism 38.

[0058] Next, in the fixing process of step S110 in Figure 7, the frame 4 of the wafer unit 2 is fixed to the fixing part 7 as shown in Figure 8(B).

[0059] Next, in the cold air cooling step S130 in Figure 7, as shown in Figure 8(C), cold air 20 is supplied from the nozzle 22 to the indoor space 17 of the cooling chamber 16 (see Figure 1), cooling the annular region 3B of the dicing tape 3 to below zero (for example, -20 to -40°C). This makes the annular region 3B of the dicing tape 3 brittle. Note that the temperature of the cold air 20 is not limited to below zero, but can be any temperature below the temperature at which the dicing tape 3 becomes brittle.

[0060] Next, in the expansion initiation step S140 in Figure 7, as shown in Figure 8(D), the expander ring moving mechanism 30 moves the expander ring 14 upward in the direction of arrow B from the retracted position in Figure 8(A) toward the expanded position, thereby initiating the expansion of the entire area of ​​the brittle annular region 3B. Note that during the expansion initiation step, the state in which cold air 20 is injected from the nozzle 22 may be maintained, and in the cold air cooling step S130, if the annular region 3B has been sufficiently cooled, the injection of cold air 20 from the nozzle 22 may be stopped.

[0061] Next, in the splitting process of step S150 in Figure 7, the wafer 1 is divided into individual chips 6 by continuing the upward movement of the expanding ring 14 as shown in Figure 9(A). After this, as shown in Figure 9(B), when the expanding ring 14 reaches the expanded position, the upward movement of the expanding ring 14 is stopped.

[0062] In the splitting process of step S150, the spring constant of the annular region 3B, which is larger than that at room temperature, is applied to the wafer 1. This allows sufficient tension to be applied from the annular region 3B to the wafer 1 to split even small chips (1 mm) into individual chips 6. Therefore, the workpiece splitting apparatus 10 can resolve the problem of undivided lines on the planned splitting line that occurs when the chip size is small (1 mm).

[0063] Next, in the heating step S160 in Figure 7, as shown in Figure 9(B), the halogen lamp 28 is lit to heat the fitting portion 26 of the expansion retaining ring 18 to a temperature above room temperature. Note that the heating step S160 may be performed during the splitting step S150, or after the completion of the splitting step S150. Furthermore, the temperature at 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 that allows the fitting portion 26, which has been brittle by the cold air 20, to recover to an elastic state.

[0064] Next, in the expanded state holding step S170 in Figure 7, as shown in Figure 9(C), the expanded holding ring 18 is raised from the standby position to the fitting position by the expanded holding ring moving mechanism 38, and the fitting portion 26, whose elastic state has been restored, is fitted to the surface 4A of the frame 4 at the fitting position to hold the expanded state of the dicing tape 3.

[0065] Next, in the expanding ring retraction step S180 in Figure 7, as shown in Figure 9(D), the expanding ring 14 is moved downward toward the retracted position by the expanding ring moving mechanism 30 and placed in the retracted position. At this time, the dicing tape 3 is released from expansion by the expanding ring 14, but the expanded state is maintained without slack because the fitting portion 26 of the expansion holding ring 18 is fitted onto the surface 4A of the frame 4. This prevents contact between the chips 6 that would occur if the expanded dicing tape 3 were to slacken, thus preventing a deterioration in the quality of the chips 6.

[0066] As described above, the workpiece splitting method using the workpiece splitting device 10 of the embodiment includes a cold air cooling step in step S130, which makes the dicing tape 3 brittle and increases the spring constant of the dicing tape 3. This eliminates the problem of undivided lines on the planned splitting line that occurs when the chip size is small.

[0067] Furthermore, according to the workpiece splitting method using the workpiece splitting device 10 of the embodiment, since the heating step S160 is included, the fitting portion 26 that has been cooled to an embrittlement state in the cold air cooling step S130 can be restored to an elastic state. After this, since the expanded state holding step S170 is included, the fitting portion 26 that has been restored to an elastic state can be fitted onto the surface 4A of the frame 4. This eliminates the problem of chip quality degradation caused by contact between chips after splitting.

[0068] In the above embodiment, a halogen lamp 28 was used as an example of a heating element, but the invention is not limited to this. For example, a far-infrared lamp, an infrared lamp, a ceramic heater, a carbon heater, a hot air heater, or a contact heater can be used as an example of a heating element. With these heating elements, even in the low-temperature environment of the cooling chamber 16, the brittle fitting portion 26 can be heated and restored to an elastic state.

[0069] Furthermore, as a heating element, an air supply unit 44 may be provided, as shown in Figure 10, to supply room temperature air 42 to the fitting portion 26 of the expansion retaining ring 18. With this heating element, even inside the cooling chamber 16 under low temperature conditions, the fitting portion 26 can be restored from a brittle state to an elastic state by supplying room temperature air 42.

[0070] In this invention, the fitting portion 26 of the expansion retaining ring 18 is heated by a heating unit in the indoor space 17 of the cooling chamber 16 in a low-temperature environment to restore it to an elastic state, and then the dicing tape 3 is held in an expanded state by the expansion retaining ring 18. However, it is also possible to fit the fitting portion 26 to the surface 4A of the frame 4 without using a heating unit. For example, the standby position of the expansion retaining ring 18 is set outside the cooling chamber 16 in a normal temperature environment, and a door is provided in the cooling chamber 16 for moving the expansion retaining ring 18 in and out. Then, when holding the expanded state of the dicing tape 3, the door is opened, the expansion retaining ring 18 is moved from outside the cooling chamber 16 to the indoor space 17, and the fitting portion 26 in a normal temperature state is fitted to the surface 4A of the frame 4. Even with such a configuration, it is possible to simultaneously resolve the problem of undivided lines in the planned division line that occurs when the chip size is small, and the problem of chip quality degradation caused by contact between divided chips. [Explanation of symbols]

[0071] 1...Wafer, 2...Wafer unit, 3...Dicing tape, 3A...Central region, 3B...Annular region, 3C...Fixed region, 4...Frame, 5...Division line, 6...Chip, 7...Fixed part, 8...Expanding ring, 10...Workpiece division device, 14...Expanding ring, 16...Cooling chamber, 17...Interior space, 18...Expanding retaining ring, 20...Cold air, 22...Nozzle, 24...Cold air supply unit, 25...Piping, 26...Matching part, 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 unit, 42...Room temperature air, 44...Air supply unit

Claims

1. In a workpiece splitting device that splits a workpiece mounted on a frame via a dicing tape into individual chips along a planned splitting line, An expanding ring for expanding the dicing tape, An expansion retaining ring formed in a ring shape having an elastically deformable fitting portion, wherein the fitting portion is fitted to the surface of the frame when the dicing tape is expanded by the expansion ring, thereby retaining the expanded state of the dicing tape. A heating unit that heats the fitting portion of the expansion retaining ring before it is fitted to the surface of the frame, A workpiece splitting device equipped with the following features.

2. The system includes a heating control unit that controls the heating time of the heating unit based on a pre-set correspondence between the heating time of the heating unit and the temperature of the fitting unit. The workpiece splitting apparatus according to claim 1.

3. The heating section makes the fitting section elastic, A workpiece splitting apparatus according to claim 1 or 2.

4. The workpiece splitting apparatus according to any one of claims 1 to 3, wherein the heating unit is a heat supply unit that supplies heat above room temperature to the fitting unit.

5. The workpiece splitting apparatus according to any one of claims 1 to 3, wherein the heating unit is an air supply unit that supplies room temperature air to the fitting unit.

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