Expand ring and method for manufacturing semiconductor chip

Abstract

To prevent chip layout from collapsing after expansion.SOLUTION: An expand ring according to an aspect of the present invention has a periphery fixed to an annular member and applies tension to a sheet material to which a wafer is attached to stretch the sheet material. The expand ring includes a ring body having an outer diameter smaller than the inner diameter of the annular member, and a lip portion which extends downward and outward from the upper outer edge of the ring body and whose tip has an outer diameter larger than the inner diameter of the annular member, and the lip portion has portions with different radial lengths in a circumferential direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an expand ring and a method for manufacturing a semiconductor chip. [Background technology]

[0002] Conventionally, in manufacturing semiconductor chips (hereinafter referred to as chips), a semiconductor wafer (hereinafter referred to as wafer) in which intended division lines have been pre-processed by, for example, laser irradiation is divided (also referred to as singulation) into individual chips along the intended division lines.

[0003] The wafer to be diced is attached to a dicing tape, and the outer periphery of the dicing tape is fixed to a frame. The wafer attached to the dicing tape may be laser diced, for example. In laser dicing, a laser beam is focused on the inside of the wafer, forming a modified region inside the wafer through the multiphoton absorption phenomenon. After laser dicing, the dicing tape is expanded with an expanding ring, dividing the wafer into individual chips starting from the modified region.

[0004] As an example of technology related to expanding rings, Patent Document 1 discloses an expanding ring that is composed of a ring body and a protruding piece that extends downward and outward from the outer upper edge of the ring body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-142199 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, probing is performed to inspect the electrical characteristics of chips before or after dicing.

[0007] Laser dicing tends to cause yielding in the wafer due to thermal effects. Therefore, when probing the laser diced wafer with a probe device, chips come into contact with each other during wafer transport, causing cracks and other defects in the chips. To prevent this defect, the inventors came up with the idea of ​​expanding the dicing tape using an expand ring after laser dicing to separate the wafer into chips, and then performing probing while the dicing tape is expanded.

[0008] However, the dicing sheet may have anisotropic stretchability. Furthermore, the amount of stretch varies depending on the position of the dicing tape. Therefore, the individual chips on the expanded dicing sheet are not evenly spaced, but are positioned according to the amount of stretch. Furthermore, depending on the layout, the individual chips may be rotated from their original position. This disrupts the chip layout after expansion. Therefore, when probing after singulation using a conventional expand ring, alignment for each chip is required. Thus, the technology described in Patent Document 1 still leaves room for improvement. Furthermore, in the case of multi-probing, in which multiple chips are simultaneously tested using a probing device, a probe card with test needles positioned corresponding to each chip is used. Therefore, controlling the position of each chip after expansion is important.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide an expanding ring and a method for manufacturing a semiconductor chip that can suppress the collapse of the chip layout after expansion. [Means for solving the problem]

[0010] The inventors came up with the idea of ​​varying the length of the lip portion of the expansion ring in the circumferential direction, thereby changing the expansion rate of the dicing sheet depending on the position, and thus came up with the present invention.

[0011] The gist of the present invention is as follows. (1) An expanding ring according to one aspect of the present invention is an expanding ring whose periphery is fixed to an annular member and which applies tension to a sheet material to which a wafer is attached to stretch the sheet material, and which comprises a ring body having an outer diameter smaller than the inner diameter of the annular member, and a lip portion which extends downward and outward from the upper outer periphery of the ring body and whose tip has an outer diameter larger than the inner diameter of the annular member, and the lip portion has portions whose radial lengths vary circumferentially. (2) In the expanding ring described in (1) above, the portions having different radial lengths may be arranged according to the chip layout. (3) In the expanding ring described in (1) or (2) above, the portions having different radial lengths may be arranged according to the anisotropy of elongation of the sheet material. (4) In the expand ring described in (1) above, the lip portion may be elliptical when viewed in the axial direction of the lip portion. (5) In the expanding ring described in (1) above, the lip portion may have protruding portions spaced at equal intervals in the circumferential direction. (6) In the expand ring described in (5) above, the lip portion may have protruding portions at every 90 degrees when viewed in the axial direction of the lip portion. (7) In the expanding ring described in any one of (1) to (6) above, the lip portion may be formed of a material softer than the ring body and may be removably attached to the outer peripheral surface of the ring body. (8) The expanding ring according to any one of (1) to (6) above may include a circumferential position adjusting portion.

[0012] (9) In addition, a method for manufacturing a semiconductor chip according to another aspect of the present invention includes a laser dicing process for laser dicing a wafer attached to a sheet material, and an expanding process for applying tension to the sheet material after the laser dicing process using an expanding ring to stretch the sheet material, wherein the expanding ring includes a ring body having an outer diameter smaller than the inner diameter of an annular member, and a lip portion extending outward and downward from the outer periphery upper edge of the ring body, the lip portion having an outer diameter at its tip that is larger than the inner diameter of the annular member, and the lip portion has portions with different radial lengths in the circumferential direction. (10) The method for manufacturing a semiconductor chip according to (9) above may include a probing step of inspecting the chips obtained by dividing the wafer in the expanding step. (11) The method for manufacturing a semiconductor chip according to (9) above may include a die bonding step of picking up the chips obtained by dividing the wafer in the expanding step and fixing them on a substrate. [Effects of the Invention]

[0013] According to the above aspect of the present invention, it is possible to suppress the collapse of the chip layout after expansion. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 10 is an explanatory diagram of a wafer unit provided with a dicing tape. [Figure 2] 1 is a cross-sectional view showing a configuration of an expanding ring according to a first embodiment of the present invention. [Figure 3] FIG. 3 is a plan view of the expand ring of FIG. 2. [Figure 4] FIG. 10 is a plan view showing another configuration of the expanding ring according to the embodiment. [Figure 5] FIG. 10 is an explanatory diagram illustrating the flow of the chip division operation by expanding. [Figure 6] FIG. 10 is an overall perspective view of a modified example of the expanding ring according to the embodiment. [Figure 7]FIG. 7 is an assembled perspective view of the expand ring shown in FIG. 6. [Figure 8] FIG. 7 is a partial cross-sectional view of the expand ring shown in FIG. 6. [Figure 9] FIG. 10 is a partial cross-sectional view showing a state in which the lip body is tilted relative to the ring body. [Figure 10] 10 is a flowchart showing the flow of a method for manufacturing a semiconductor chip according to a second embodiment of the present invention. [Figure 11] 10 is a flowchart showing a flow of a method for manufacturing a semiconductor chip according to the embodiment. [Figure 12] FIG. 10 is a partial cross-sectional view of a wafer unit for explaining a deformation region. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Wafer unit> First, before describing an expand ring according to one embodiment of the present invention, the configuration of a wafer unit will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram of a wafer unit 1 equipped with a dicing tape 4 (sheet material), with Fig. 1(A) being a perspective view of the wafer unit 1 and Fig. 1(B) being a cross-sectional view of the wafer unit 1.

[0016] As shown in FIG. 1, a wafer unit 1 includes a wafer 2, a film-like adhesive 3, a dicing tape 4, and a frame 5 (annular member). The wafer 2 is attached to the dicing tape 4, which has a thickness of approximately 100 μm and an adhesive layer formed on its surface, via the film-like adhesive 3. The dicing tape 4 has an outer periphery fixed to a rigid annular frame 5. As shown in FIG. 1B, the dicing tape 4 includes a central region 4A, which is circular in plan view, to which the wafer 2 is attached, and an annular region 4B, which is donut-shaped in plan view, between the outer edge of the central region 4A (the outer edge of the wafer 2) and the inner edge of the frame 5. The wafer 2 is loaded into a work dividing device (not shown) in the form of the wafer unit 1, and is divided into individual chips 6 by an expander ring 10 (described later) in the work dividing device.

[0017] <Expanding ring> Next, an expanding ring according to a first embodiment of the present invention will be described with reference to the drawings. The proportions and dimensions of the components in the drawings do not represent the actual proportions and dimensions of the components. The dimensions shown are merely examples, and it goes without saying that the present invention is not limited to these. Fig. 2 is a cross-sectional view showing the configuration of an expanding ring 10 according to a first embodiment of the present invention. Fig. 3 is a plan view of the expanding ring 10 of Fig. 2.

[0018] As shown in Figures 2 and 3, the expand ring 10 is composed of a ring body 12 and a lip portion 14 extending downward and outward from the upper outer periphery of the ring body 12. The expand ring 10 has its periphery fixed to an annular member, and applies tension to a sheet material to which wafers 2 are attached, stretching the sheet material. The outer diameter D1 of the ring body 12 is smaller than the inner diameter of the frame 5 (see Figure 1), which is an annular member. The outer diameter D2 of the lip portion 14 is larger than the inner diameter of the frame 5.

[0019] By configuring the expanding ring 10 relative to the frame 5 in this way, when the expanding ring 10 is pressed against the dicing tape 4 from below and tension is applied to the dicing tape 4 to stretch it, the lip portion 14 bends downward, and the tip of the lip portion 14 climbs over the inner diameter portion of the frame 5, then the lip portion 14 recovers from its bending, and the tip of the lip portion 14 engages with the upper surface of the frame 5 via the dicing tape 4. This allows the dicing tape 4 to remain stretched. Details of this will be described later with reference to FIG. 5.

[0020] There are no particular limitations on the material, height, ring thickness, etc. of the ring body 12, and appropriate material and size can be selected depending on the size, thickness, and material of the dicing tape 4 and the size (particularly the inner diameter) of the frame 5. The ring body 12 is made of metal, for example. While aluminum is an example of the metal material that makes up the ring body 12, it is not limited to aluminum, and any metal material with high rigidity that is resistant to deformation when the dicing tape 4 is expanded (state VB in FIG. 5) and when it is held expanded (state VC in FIG. 5) can be used.

[0021] The lip portion 14 has portions with different radial lengths in the circumferential direction. The portions with different radial lengths are preferably arranged according to the chip layout. For example, the smaller the chip size, the greater the amount of stretch of the dicing tape 4. Furthermore, the greater the aspect ratio of the chip, the greater the amount of stretch of the dicing tape 4 along the lateral direction of the chip. On the other hand, near the portions of the dicing tape 4 where the radial length of the lip portion 14 is long, in other words, near the portions where the protrusion amount is large, the expansion rate of the dicing tape 4 increases, thereby widening the chip spacing. Therefore, when the aspect ratio of the chip is large, by arranging the portions of the lip portion 14 where the radial length is long in the lateral direction of the chip, the chip spacing within the wafer surface can be made uniform.

[0022] The expanding ring 10 is equipped with a circumferential position adjustment unit. For example, a recess can be provided on a portion of the inner diameter side of the ring body 12 of the expanding ring 10, and a protrusion that fits into the recess can be provided on the device side (e.g., the lifting stage 26 shown in FIG. 5), and positioning can be achieved by the engagement of the recess and protrusion. Alternatively, for example, a hole can be provided in the ring body 12 of the expanding ring 10, and a rod that passes through the hole can be provided on the device side, and positioning can be achieved by inserting the rod into the hole in the ring body 12. Therefore, circumferential position adjustment is possible.

[0023] The lip portion 14 is, for example, elliptical when viewed from the axial direction, as shown in Fig. 3. With such a shape, the expansion rate of the dicing tape 4 in the major axis direction increases relative to the minor axis direction, making it possible to make the chip spacing within the wafer surface uniform.

[0024] Furthermore, the lip portion 14 preferably has overhanging portions 140 spaced at equal intervals in the circumferential direction when viewed from the axial direction of the lip portion 14. For example, in FIG. 4, the overhanging portions 140 are arranged on the lip portion 14 at 90-degree intervals when viewed from the axial direction of the lip portion 14. With this shape, the expansion rate of the dicing tape 4 increases near the overhanging portions 140, allowing the chip spacing to be increased. As a result, the chip spacing within the wafer surface can be made uniform.

[0025] If the dicing tape 4 has anisotropy in its elongation, it is preferable that the portions with different radial lengths be arranged in accordance with the anisotropy in the elongation of the dicing tape 4. This makes it possible to prevent the chip layout from collapsing due to the anisotropy in the elongation of the dicing tape 4.

[0026] There are no particular restrictions on the material of the lip portion 14, the inclination angle relative to the axis of the ring body 12, the radial thickness distribution, etc., and appropriate material and size can be selected depending on the size, thickness, and material of the dicing tape 4, the size (especially the inner diameter) of the frame 5, etc.

[0027] For example, a metal material that undergoes elastic deformation or a resin that undergoes elastic deformation is preferably used for the lip portion 14. Examples of metal materials include stainless steel. Examples of resins include polyacetal, polyamide, and various engineering plastics. Furthermore, the ring body 12 and the lip portion 14 may be made of the same material or different materials.

[0028] There are no limitations on the method for forming the expand ring 10. For example, the expand ring 10 may be formed by machining a metal material by cutting, by shrink-fitting a ring body 12 and a lip portion 14 that have been machined, or by injection molding a resin.

[0029] 2, it is preferable that the thickness of the lip portion 14 decreases from the base end toward the tip end. With such a lip portion 14, the tip end climbs over the inner diameter portion of the frame 5, and then the deflection of the lip portion 14 is restored, and the tip end of the lip portion 14 can easily engage with the upper surface of the frame 5 via the dicing tape 4.

[0030] Here, the flow of the chip dividing operation using the expand ring will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram illustrating the flow of the chip dividing operation by expanding.

[0031] Figure 5(A) shows the state in preparation for expansion. In Figure 5(A), the dicing tape 4 adhered to the backside of the wafer 2 is placed on the wafer table 20. At this time, the frame 5 is placed on a frame support base 22 and is pressed from above by a frame presser 24, restricting movement. In this state, the dicing tape 4 maintains a horizontal position.

[0032] The expand ring 10 is fixed on a lift stage 26, and is at its lowest position in the state shown in FIG. 5(A).

[0033] The wafer table 20 is provided with a heating means (not shown), which heats the wafer 2 and dicing tape 4 to a predetermined temperature.

[0034] 5(A), protective tape H is peeled off from the surface of wafer 2 in the direction of the arrow in the figure. This protective tape H is attached to protect the surface of wafer 2 during a previous process such as backgrinding. During laser dicing, laser light is incident on the inside of wafer 2 with protective tape H attached.

[0035] Figure 5(B) shows the state in which the wafer 2 is being expanded. In Figure 5(B), the lift stage 26 rises from the lowest position in Figure 5(A), and the expand ring 10 comes into contact with the wafer 2, pushing the wafer 2 upward and expanding it. At the same time, cooling air is ejected in the direction of the arrow in the figure from air ejection holes (not shown) provided in the expand ring 10, cooling the dicing tape 4. This promotes the expansion of the dicing tape 4.

[0036] 5(B), if the lifting stage 26 is further raised, the lip portion 14 of the expanding ring 10 bends downward, and the tip of this lip portion 14 climbs over the inner diameter portion of the frame 5, then the lip portion 14 recovers from its bending, and the tip of this lip portion 14 engages with the upper surface of the frame 5 via the dicing tape 4, thereby maintaining the dicing tape 4 in a stretched state. Figure 5(C) shows this state.

[0037] When the expanding ring 10 is inserted into the frame 5 in an upward direction, the lip portion 14 is formed in a shape that expands in diameter downward. With the expanding ring 10 having such a lip portion 14, the expanding ring 10 can pass through the frame 5 when moving in the insertion direction (upward), but cannot pass through the frame 5 when moving in the opposite direction (downward) after passing through the opening 51.

[0038] 5(C), the lift stage 26 has lowered to its lowest position, and the frame 5, dicing tape 4, and expanding ring 10 are integrated together. In this state, if the pressure from the frame presser 24 is released, the frame 5, dicing tape 4, and expanding ring 10 can be transported to the next process in this integrated state.

[0039] According to the present embodiment described above, the dicing tape 4 can be uniformly expanded using a simple tool (expanding ring 10), and the expanded state of the dicing tape 4 can be easily maintained with the gap between the chips widened. This makes it possible to expand the wafer 2 with an improved yield.

[0040] <Modification> Modified examples of the expanding ring according to this embodiment will be described with reference to Figures 6 to 8. Figure 6 is an overall perspective view of an expanding ring 10' according to a modified example of this embodiment. Figure 7 is an assembled perspective view of the expanding ring 10' shown in Figure 6. Figure 8 is a partial cross-sectional view of the expanding ring 10' shown in Figure 6.

[0041] As shown in FIGS. 6 to 8, the expand ring 10' includes a ring body 12' and a lip portion 14'.

[0042] 8, the ring body 12' has an annular recessed portion 122 formed along the outer circumferential surface 121 of the ring body 12'. The lip portion 14' has an annular main body portion 141 that is inserted into the annular recessed portion 122. That is, the lip portion 14' is detachably attached to the ring body 12' by inserting the annular main body portion 141 into the annular recessed portion 122.

[0043] The material of the ring body 12' can be the same as the material of the ring body 12 described above.

[0044] The lip portion 14' is formed of a softer material than the ring body 12'. The lip portion 14' protrudes outward from the outer peripheral surface 121 of the ring body 12'. The outer diameter of the lip portion 14' is configured to be larger than the inner diameter of the opening 51 of the frame 5. With this configuration, when the lip portion 14' passes through the opening 51 of the frame 5 shown in FIG. 8, it is pressed against the inner edge of the opening 51, elastically deforming and reducing in diameter. Then, after passing through the opening 51, it elastically returns to its original shape, expands in diameter, and fits onto the surface 52 of the frame 5 via the annular region 4B of the dicing tape 4.

[0045] As shown in Fig. 8, a fluororesin coating layer 123 is provided on the outer surface of the ring body 12'. This fluororesin coating layer 123 reduces the frictional force between the upper surface 124 of the ring body 12' (the surface that pushes up the annular region 4B in Fig. 4) and the annular region 4B of the dicing tape 4. As a result, as shown in Fig. 5(B), when the expanding ring 10' pushes up the annular region 4B, the annular region 4B of the dicing tape 4 becomes more likely to slide relative to the upper surface 124 of the ring body 12, thereby preventing damage to the dicing tape 4.

[0046] The expanding ring 10' of the embodiment configured as described above has the following advantages: The lip portion 14' is formed from a softer material than the ring body 12' and is configured to be removably attached to the outer peripheral surface 121 of the ring body 12', so that when the dicing tape 4 is expanded (the state shown in FIG. 5(B)), it is possible to maintain the annular shape of the ring body 12' and to ensure the flexibility of the lip portion 14'.

[0047] Furthermore, if the ring body 12' is made of metal, the ring body 12' can easily maintain its annular shape. This prevents the expanding ring 10' from falling off the frame 5 even when applied to a dicing tape 4 with high tension. Furthermore, if the lip portion 14' is made of resin, the lip portion 14' can easily deform. This prevents the dicing tape 4 from being damaged when it is expanded.

[0048] 8, the expand ring 10' of this embodiment is configured so that the dimension a of the lip portion 14' in the thickness direction of the expand ring 10' is smaller than the dimension b of the annular recess 122. By adopting this configuration, it is possible to minimize the amount of elastic deformation of the lip portion 14'. Note that the thickness direction of the expand ring 10' and the direction of the central axis C of the lip portion 14' are the same.

[0049] 9, the lip portion 14' is pressed relatively against the inner edge of the frame 5 while passing through the opening 51 of the frame 5 (while elastically deforming). As a result, the lip portion 14' tilts in the direction indicated by arrow A (downward) around the outer peripheral edge 141A of the annular main body 141, which is in contact with the outer peripheral end 122A of the annular recess 122 of the ring body 12'. The lip portion 14' is then elastically deformed in the same direction as the tilt, and elastically returns to its original shape when it passes through the opening 51, fitting into the surface 52 of the frame 5.

[0050] If the dimension a of the annular main body portion 141 of the lip portion 14' and the dimension b of the annular recessed portion 122 of the ring body 12' are equal, the tilting motion of the annular main body portion 141 (tilting of the annular main body portion 141 in the direction indicated by arrow A) described above does not occur. Therefore, the elastic deformation of the lip portion 14' passing through the opening 51 places a large load on the lip portion 14'. Therefore, the expanding ring 10' of this embodiment employs a configuration in which the dimension a of the annular main body portion 141 of the lip portion 14' is smaller than the dimension b of the annular recessed portion 122 of the ring body 12'. This minimizes the elastic deformation of the lip portion 14', thereby extending the service life of the lip portion 14'. Furthermore, the above configuration reduces the load applied to the dicing tape 4 from the lip portion 14', thereby reducing damage to the dicing tape 4.

[0051] 8, the expanding ring 10' has a tapered surface 126 formed on the inner peripheral surface 125 of the ring body 12' that is inclined obliquely with respect to the central axis C of the ring body 12'. In FIG. 8, when the expanding ring 10' is inserted into the frame 5 in the upward direction, the tapered surface 126 is inclined in a direction that expands the diameter of the opening of the ring body 12' from the top to the bottom.

[0052] According to the present embodiment described above, the dicing tape 4 can be uniformly expanded using the expanding ring 10', and the expanded state of the dicing tape 4 can be easily maintained with the gap between the chips widened. This makes it possible to expand the wafer 2 with an improved yield.

[0053] <Semiconductor chip manufacturing method> Next, a method for manufacturing a semiconductor chip according to the second embodiment of the present invention will be described. Figures 10 and 11 are flowcharts showing the flow of the method for manufacturing a semiconductor chip according to the second embodiment of the present invention.

[0054] The method for manufacturing semiconductor chips according to this embodiment includes a laser dicing process (step S1) in which a semiconductor wafer attached to a sheet material is laser diced, an expanding process (step S2) in which an expanding ring is used to apply tension to the sheet material after the laser dicing process to stretch the sheet material, and a probing process (step S3) in which the chips separated from the semiconductor wafer by the expanding process are inspected.

[0055] (Laser dicing process) In the laser dicing process, a semiconductor wafer attached to a sheet material is laser diced. A known laser dicing method can be applied to this process, for example, the dicing method described in JP 2015-186825 A. The laser dicing method applied to the laser dicing process is not limited to the above method.

[0056] (Expanding process) After the laser dicing process, an expanding process is carried out. In the expanding process, an expanding ring is used to apply tension to the sheet material after the laser dicing process to stretch the sheet material. The expanding ring used in the expanding process is the expanding ring described above. That is, the expanding ring used in the expanding process comprises a ring body having an outer diameter smaller than the inner diameter of the annular member, and a lip portion extending outward and downward from the upper outer periphery of the ring body, with the outer diameter of the tip portion being larger than the inner diameter of the annular member, and the lip portion having portions with different radial lengths in the circumferential direction. The expanding method may be any of the methods described above.

[0057] (probing process) After the expanding process, a probing process is carried out. In the probing process, the chips obtained by dividing the semiconductor wafer into individual chips by the expanding process are inspected. A known probing method can be applied to this process. In this process, it is preferable to perform multi-probing, which inspects multiple chips simultaneously. In multi-probing, a probe card is used in which inspection needles are set at positions corresponding to each chip. By performing the above-mentioned expanding process, the collapse of the chip layout after expansion is suppressed, making multi-probing possible without performing alignment for each chip.

[0058] (Die bonding process) As shown in FIG. 11, the semiconductor chip manufacturing method according to this embodiment may include a die bonding process (step S4) instead of the probing process. The die bonding process may be performed by a known method. In this process, the position of the chip is recognized, picked up, and placed on the substrate. By performing the above-described expanding process, the collapse of the chip layout after expansion is suppressed, so that the chips can be picked up without aligning each chip.

[0059] The present invention has been described above using the present embodiment. However, the technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0060] For example, in the state shown in FIG. 5(C), the wafer 2 may be image-recognized from above by an image recognition device (not shown) to identify the divided state of the wafer 2.

[0061] The lip portion 14' of the expanding ring 10' may be colored a different color from the ring body 12'. For example, if the ring body 12' is black, the lip portion 14' may be colored blue. The lip portion 14' may be colored a different color for each production lot of the lip portion 14'. This allows the production lot of the lip portion 14' to be identified by looking at the color of the lip portion 14'. As a result, if a lip portion 14' is found to have exceeded its service limit, the use of all other lip portions 14' (i.e., expanding rings 10') manufactured in the same production lot as the lip portion 14' can be immediately stopped. This prevents the expanding ring 10' from falling off the frame 5. One method for coloring the lip portion 14' is to add a pigment to the resin material of the lip portion 14'.

[0062] Furthermore, although the ring body 12' in the above embodiment has the tapered surface 126, it does not have to have the tapered surface 126.

[0063] Furthermore, in the above-described embodiment, the expanding rings 10, 10' are used to expand the dicing tape 4 and separate the wafer 2 into chips, but the dicing tape 4 may be expanded by other expanding rings, and the expanding rings 10, 10' may be used as expansion retaining rings to maintain the dicing tape 4 in its expanded state. [Example]

[0064] The effects of one embodiment of the present invention will be explained in more detail using examples. However, the conditions in the examples are merely examples adopted to confirm the feasibility and effects of the present invention. The present invention is not limited to these examples. Various conditions may be adopted in the present invention as long as they do not deviate from the gist of the present invention and achieve the object of the present invention.

[0065] Example 1 A wafer unit shown in FIG. 1 was prepared, and the chip spacing was calculated when the wafer unit was expanded using an elliptical annular expanding ring (Example 1 of the present invention) or a circular annular expanding ring (Comparative Example 1).

[0066] The frame of the wafer unit had an inner diameter d of 350 mm and a thickness of 1.5 mm. The outer diameter D of the wafer was 300 mm. The center of the frame and the center of the wafer were assumed to be aligned. Therefore, the width of the annular region 4B was 25 mm.

[0067] The dicing tape was assumed to have anisotropy in elongation, with the easy and difficult directions being perpendicular to each other, and the ratio of the elongation ratio (the amount of elongation in the easy direction relative to the amount of elongation in the difficult direction when a constant force is applied in each direction) was set to 3. The thickness of the dicing tape was set to 0.1 mm. The wafer was laser-machined in lines at 3 mm intervals in mutually perpendicular directions. Therefore, the number of processing lines was 100. When the dicing tape was expanded, the wafer was divided into multiple chips at the laser-machined portions. Furthermore, each direction of laser processing was assumed to coincide with the direction of expansion of the dicing tape with the above-mentioned anisotropy. Therefore, when the dicing tape was expanded, the length of the affected area in the direction that easily stretched was 30 mm, and the length of the affected area in the direction that was difficult to stretch was 10 mm. Furthermore, the length of the deformation area in the direction that easily stretched was 80 mm, and the length of the deformation area in the direction that was difficult to stretch was 60 mm.

[0068] The affected area length and the deformed area length will now be described with reference to FIG. 12. FIG. 12 is a partial cross-sectional view of a wafer unit to explain the deformed area. FIG. 12 shows the state after expansion. The expansion causes the dicing tape 4 to peel off from the film-like adhesive 3, creating a gap 7 between the wafer 2 and the film-like adhesive 3. Furthermore, a region 41, where the thickness has been reduced by the expansion, is created in the dicing tape 4 below the gap 7. If the width of this gap 7 is g and the width of the region 41 is l, the length that the dicing tape 4 can potentially stretch due to the expansion is expressed as lg. If the thickness of the dicing tape 4 is t and the ratio of the length that the dicing tape 4 can potentially stretch to the tape thickness t is a1, then a1 = (lg) / t. The ratio a1 of the length that the dicing tape 4 can potentially stretch to the tape thickness t is called the affected area factor. As the affected area factor a1 increases, the chip spacing increases.

[0069] The length a0 of the area of ​​influence in one direction of the wafer 2 is the product of the tape thickness t, the area of ​​influence factor a1, and the number of processing lines n, and is expressed by the following formula. a0=t×a1×n=t×((lg) / t)×n=n×(lg) The affected area length a0 is the length of the dicing tape 4 within the plane of the wafer 2 that can be stretched by the application of an external force (expanding). Therefore, the amount of stretch of the dicing tape 4 is the sum of the affected area length a0 and the stretch of the dicing tape 4 on the outer circumferential side of the wafer 2. For example, let's assume that the diameter of the wafer 2 is 300 mm and the chip size (index size) is 3 mm. In this case, the number of processing lines n is 300 / 3 = 100. Let's also assume that the influence area factor a1 is 1 and the tape thickness t is 0.1 mm. In this case, the influence area length a0 is a0 = t × a1 × n = 0.1 × 1 × 100 = 10 mm. In other words, in the direction perpendicular to the processing lines of the wafer 2, only 10 mm of the 300 mm contributes to the elongation of the dicing tape 4. If the elongation amount of the dicing tape 4 on each side of the outer periphery of the wafer 2 in the above direction is 25 mm, the elongation amount of the dicing tape 4, i.e., the deformation area length, is 25 + 10 + 25 = 60 mm.

[0070] (Example 1 of the present invention) The elliptical annular expand ring used had a ring body and a lip portion attached to the outer peripheral surface of the ring body, as shown in Figure 6. The height of the ring body was 4 mm, and the outer diameter of the ring body was 348.5 mm. The minor axis of the lip portion of the expand ring was 351.3 mm, and the major axis was 357.3 mm. The lip portion protruded by 0.65 mm on both sides in the minor axis direction and by 3.65 mm on both sides in the major axis direction.

[0071] The ellipsoidal annular expanding ring was used to expand the dicing tape of the wafer unit in the manner described above with reference to Figure 5. At this time, the minor axis direction of the expanding ring was aligned with the direction in which the dicing tape easily stretches, and the major axis direction of the expanding ring was aligned with the direction in which the dicing tape is less likely to stretch.

[0072] (Comparative Example 1) The height of the ring body of the annular expand ring was 4 mm, and the outer diameter was 348.5 mm. The diameter of the lip of the expand ring was 351.3 mm. The lip protruded by 0.65 mm.

[0073] The dicing tape of the wafer unit was expanded using the annular expand ring in the manner described above with reference to FIG.

[0074] Table 1 shows the amount of elongation of the dicing tape after expansion in the easy and difficult directions, the expansion rate of the deformation region, the increase in wafer diameter, and the chip spacing for Example 1 of the present invention and Comparative Example 1. The expansion rate of the deformation region (%) was calculated by multiplying the amount of elongation of the dicing tape by the length of the deformation region x 100. The increase in wafer diameter was calculated by multiplying the expansion rate of the deformation region by the length of the affected region a0. The chip spacing was calculated by dividing the increase in wafer diameter by the number of processing lines.

[0075] [Table 1]

[0076] As shown in Table 1, in Example 1 of the present invention, which used an elliptical annular expanding ring, it was found that the chip spacing could be made approximately equal in the easy-to-expand direction and the difficult-to-expand direction compared to Comparative Example 1, which used a circular annular expanding ring. In other words, it was found that variations in the chip layout could be suppressed. <Example 2> A wafer unit shown in FIG. 1 was prepared, and the chip spacing was calculated when the wafer unit was expanded using an elliptical annular expanding ring (Example 2 of the present invention) or a circular annular expanding ring (Comparative Example 2).

[0077] The frame of the wafer unit had an inner diameter d of 350 mm and a thickness of 1.5 mm. The outer diameter D of the wafer was 300 mm. The center of the frame and the center of the wafer were assumed to be aligned. Therefore, the width (radial length) of the annular region 4B was 25 mm.

[0078] The dicing tape had no anisotropy in elongation and a thickness of 0.1 mm. The wafer was assumed to have linear laser processing in mutually orthogonal directions. The laser processing was performed at 20 mm intervals in a first direction of the mutually orthogonal directions, and at 1 mm intervals in a second direction orthogonal to the first direction. When the dicing tape was expanded, the wafer was divided into multiple chips at the laser-processed portions. Therefore, when the dicing tape was expanded, the area of ​​influence in the first direction was assumed to be 3 mm, and the area of ​​influence in the second direction was assumed to be 60 mm.

[0079] The deformation area in the first direction was set to 53 mm, and the deformation area in the second direction was set to 110 mm.

[0080] (Example 2 of the present invention) The elliptical annular expand ring of Invention Example 2 was the same as the elliptical annular expand ring of Invention Example 1. The minor axis direction of the expand ring was aligned with the first direction, and the major axis direction of the expand ring was aligned with the second direction.

[0081] (Comparative Example 2) The annular expand ring of Comparative Example 2 was the same as the annular expand ring of Comparative Example 1.

[0082] Table 1 shows the elongation amount of the dicing tape after expansion in the first direction and the second direction, the expansion rate of the deformation region, the increase in wafer diameter, and the chip spacing in Example 2 of the present invention and Comparative Example 2.

[0083] [Table 2]

[0084] As shown in Table 2, in Example 2 of the present invention, which used an elliptical annular expanding ring, it was found that the chip spacing could be made approximately equal in the easy-to-expand direction and the difficult-to-expand direction compared to Comparative Example 2, which used a circular annular expanding ring. In other words, it was found that variations in the chip layout could be suppressed.

[0085] In Examples 1 and 2, the shape of the expansion ring was an elliptical ring, but it is clear that the expansion process can be carried out while maintaining the layout by appropriately changing the protruding length of the lip portion in the circumferential direction according to the desired chip layout. [Explanation of symbols]

[0086] 1 wafer unit 2 wafers 3 Film adhesive 4 Dicing tape 4A Central area 4B Annular region 5 frames 6 chips 7. Gap 10 Expanding Ring 10' Expanding Ring 12 Ring body 12' ring body 14 Lip 14' lip 20 wafer table 22 Frame support stand 24 Frame holder 26 Elevating Stage 41 areas 51 Aperture 52 Surface 121 Outer surface 122 Annular recess 122A Outer edge 123 Fluorine resin coating layer 124 Top 125 Inner surface 126 Tapered surface 127 Opening 140 overhang 141 Annular body 141A Outer edge

Claims

1. An expand ring having a peripheral edge fixed to an annular member, which applies tension to a sheet material to which a wafer is attached to stretch the sheet material, a ring body having an outer diameter smaller than an inner diameter of the annular member; a lip portion extending outwardly and downwardly from an outer peripheral upper edge of the ring body, the outer diameter of the tip portion being larger than the inner diameter of the annular member; The lip portion has a portion in the circumferential direction whose radial length varies.

2. The expand ring according to claim 1 , wherein the portions having different radial lengths are arranged according to a chip layout.

3. The expand ring according to claim 1 or 2, wherein the portions having different radial lengths are arranged according to anisotropy of elongation of the sheet material.

4. The expand ring according to claim 1 , wherein the lip portion is elliptical when viewed in the axial direction of the lip portion.

5. The expand ring according to claim 1 , wherein the lip portion has protruding portions spaced equally apart in the circumferential direction.

6. The expand ring according to claim 5 , wherein the lip portion has protruding portions at every 90 degrees when viewed in the axial direction of the lip portion.

7. 3. The expand ring according to claim 1, wherein the lip portion is formed of a material softer than the ring body and is detachably attachable to the outer peripheral surface of the ring body.

8. The expand ring according to claim 1 or 2, comprising a circumferential position adjustment portion.

9. a laser dicing step of laser dicing the wafer attached to the sheet material; an expanding step of applying tension to the sheet material after the laser dicing step using an expanding ring to stretch the sheet material, The expand ring is a ring body having an outer diameter smaller than an inner diameter of the annular member; a lip portion extending outwardly and downwardly from an outer peripheral upper edge of the ring body, the outer diameter of the tip portion being larger than the inner diameter of the annular member; The lip portion has a portion in the circumferential direction whose radial length varies.

10. The method for manufacturing semiconductor chips according to claim 9 , further comprising a probing step of inspecting the chips obtained by dividing the wafer into individual chips in the expanding step.

11. The method for manufacturing a semiconductor chip according to claim 9, further comprising a die bonding step of picking up the chips obtained by dividing the wafer in the expanding step and fixing the chips on a substrate.

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