Manufacturing method of semiconductor device and semiconductor wafer sheet

Abstract

To provide a manufacturing method of a semiconductor device and a semiconductor wafer sheet that can manage the semiconductor wafer and a mask used when irradiating radiation to a sheet bonded to the semiconductor wafer in association with each other.SOLUTION: A manufacturing method of a semiconductor device of the present disclosure includes the steps of: attaching a semiconductor wafer to a surface of a sheet having reduced adhesion by radiation; mounting an annular holder surrounding the semiconductor wafer on an outer peripheral part of the surface of the sheet; dicing the semiconductor wafer into a rectangular semiconductor chip, shielding at least a part of a region of the sheet adhered to a non-rectangular chip formed on an outer peripheral part of the semiconductor wafer by dicing with a mask disposed on a back surface side of the sheet; and irradiating the back surface of the sheet with radiation. The mask has the same size as the holder in plan view.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device and a sheet for a semiconductor wafer. [Background technology]

[0002] When a semiconductor wafer is diced, non-rectangular chips are generated on the periphery of the semiconductor wafer. If the semiconductor wafer is attached to a sheet, these non-rectangular chips may jump around when the semiconductor chips are peeled off the sheet, which may damage the surface of the semiconductor chip or cause malfunctions by adhering to the surface.

[0003] The radiation irradiation device in Patent Document 1 discloses a technique in which a mask is placed between the radiation source and a semiconductor wafer attached to a sheet whose adhesive strength is reduced by radiation, to partially prevent radiation irradiation. By placing the mask, radiation can be shielded from the area of ​​the sheet that is attached to the non-rectangular chip, allowing adhesive strength to be maintained. On the other hand, radiation can be irradiated to the area of ​​the sheet that is attached to the semiconductor chip, reducing adhesive strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-003613 Summary of the Invention [Problem to be solved by the invention]

[0005] Since the size and shape of the effective area of ​​semiconductor wafers vary widely, it is necessary to use a mask appropriate for the semiconductor wafer when irradiating it with radiation. However, conventional techniques have the problem that it is not possible to associate and manage the semiconductor wafer with the mask used when irradiating the sheet attached to the semiconductor wafer with radiation. As a result, there is a risk of using the wrong mask for radiation irradiation.

[0006] In order to solve the above-mentioned problems, the first object of the present disclosure is to provide a method for manufacturing a semiconductor device that can associate and manage a semiconductor wafer with a mask used when irradiating a sheet adhered to the semiconductor wafer.

[0007] A second object of the present disclosure is to provide a sheet for semiconductor wafers that can be managed in association with a semiconductor wafer and a mask used when irradiating the sheet adhered to the semiconductor wafer with radiation. [Means for solving the problem]

[0008] A first aspect of the present disclosure is Attaching a semiconductor wafer to a surface of a sheet whose adhesive strength is reduced by radiation; attaching an annular holder to the outer periphery of the front surface of the sheet so as to surround the semiconductor wafer; dicing the semiconductor wafer into rectangular semiconductor chips; irradiating the back surface of the sheet with radiation after shielding, with a mask arranged on the back surface side of the sheet, at least a part of an area of ​​the sheet that will be adhered to a non-rectangular chip generated on the outer periphery of the semiconductor wafer by dicing; Including, In the method for manufacturing a semiconductor device, the mask preferably has the same size as the holder in a plan view.

[0009] A second aspect of the present disclosure is The sheet is preferably for semiconductor wafers, having on its surface an adhesive layer whose adhesive strength is reduced by radiation, and on its back surface a mask of a shielding agent that absorbs or scatters the radiation. [Effects of the Invention]

[0010] According to the first aspect of the present disclosure, the radiation-shielding mask has the same size in plan view as the annular holder attached to the sheet to be adhered to the semiconductor wafer. Therefore, the mask can be stored in the same magazine as the semiconductor wafer. This allows the semiconductor wafer and the mask to be managed in association with each other.

[0011] According to the second aspect, the sheet and the mask are integrated by applying a shielding agent to the rear surface of the sheet to which the semiconductor wafer is adhered, which allows the semiconductor wafer and the mask to be managed in association with each other. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a flowchart showing an outline of a method for manufacturing a semiconductor device according to a first embodiment. [Figure 2] FIG. 1 is a plan view of a diced semiconductor wafer according to a first embodiment. [Figure 3] FIG. 3 is a side view of FIG. 2. [Figure 4] 3A to 3C are diagrams illustrating a method of storing semiconductor wafers in a magazine according to the first embodiment. [Figure 5] 1 is a plan view showing a state in which a holder is attached to a seat according to a first embodiment. FIG. [Figure 6] 1 is a cross-sectional view of a radiation irradiation device to which a semiconductor wafer according to a first embodiment is attached. [Figure 7] FIG. 1 is a plan view of a mask according to a first embodiment. [Figure 8] 1 is a top view showing a state in which semiconductor wafers and masks according to the first embodiment are stored in the same magazine. [Figure 9] FIG. 10 is a cross-sectional view of a radiation irradiation device to which a semiconductor wafer according to a second embodiment is attached. [Figure 10] 10 is a modified example of the radiation irradiation device of FIG. [Figure 11] FIG. 11 is a cross-sectional view of a radiation irradiation device to which a semiconductor wafer according to a third embodiment is attached. [Figure 12] 12 is a modified example of the radiation irradiation device 100 of FIG. [Figure 13] FIG. 10 is a cross-sectional view of a radiation irradiation device to which a semiconductor wafer according to a fourth embodiment is attached. [Figure 14] 10 is a diagram illustrating a defect that occurs when oxygen gets into the adhesive layer of the sheet according to embodiment 4. FIG. [Figure 15] FIG. 11 is a cross-sectional view of a radiation irradiation device to which a semiconductor wafer according to a fifth embodiment is attached. [Figure 16] FIG. 10 is a plan view of a mask according to a fifth embodiment. [Figure 17] FIG. 13 is a diagram showing the back surface of a sheet according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiments of the present disclosure will be described with reference to the drawings. The same or corresponding components will be designated by the same reference numerals, and repeated description may be omitted.

[0014] Embodiment 1 FIG. 1 is a flowchart outlining a manufacturing method for a semiconductor device according to the first embodiment. First, a semiconductor layer is formed on a semiconductor substrate, and a semiconductor wafer 30 including an integrated circuit is formed by using semiconductor processes such as exposure and etching (step S01). Next, the semiconductor wafer 30 is attached to the surface of a sheet 40 whose adhesive strength is reduced by radiation (step S02). The semiconductor wafer 30 is then cut using a dicing device while attached to the sheet 40, and divided into rectangular semiconductor chips 32 (step S03). The diced semiconductor wafer 30 is then attached to the sheet and mounted in a radiation irradiation device 100 (described later), and the backside of the sheet 40 is irradiated with radiation (step S04). The semiconductor wafer 30 is then loaded into a pickup device such as a chip transfer machine, and the semiconductor chips 32 are peeled off from the sheet 40 (step S05). The semiconductor chips 32 are then mounted on a circuit board and bonded to a lead frame (step S06). Finally, the semiconductor chips 32, the circuit board, the lead frame, and the like are packaged in resin (step S07).

[0015] The semiconductor wafers 30 attached to the sheet 40 in step S02 are stored in a magazine 200 and then transported to a dicing device in step S03. The semiconductor wafers 30 diced in step S03 are also stored in a magazine 200 and then transported to a radiation irradiation device 100 in step S04. The semiconductor wafers 30 irradiated in step S04 are also stored in a magazine 200 and then transported to a pickup device in step S05. A transport robot such as an AMR (Autonomous Mobile Robot) may be used to transport the magazines 200.

[0016] FIG. 2 is a plan view of a diced semiconductor wafer 30 according to the first embodiment. Here, the semiconductor wafer 30 is attached to a sheet 40. In the semiconductor wafer 30, a plurality of semiconductor chips 32 that can be used as products are included inside an effective area 1 surrounded by a dashed line. In many cases, the semiconductor wafer 30 is disk-shaped, but the semiconductor chips 32 are rectangular, so the periphery of the effective area 1 has a partially stepped shape. Furthermore, the semiconductor wafer 30 includes a plurality of non-rectangular chips 31, each of which has a portion of the rectangle missing, outside the effective area 1. Note that the semiconductor wafer 30 has an orientation flat 33 for positioning, but a notch may be provided instead of the orientation flat 33.

[0017] Fig. 3 is a side view of Fig. 2. Sheet 40 has an adhesive layer 41 on its front surface and a base material 42 on its back surface. Semiconductor wafer 30 is attached to adhesive layer 41 of sheet 40.

[0018] 4 is a diagram illustrating a method for storing semiconductor wafers 30 in magazine 200 according to the first embodiment. Semiconductor wafers 30 attached to sheet 40 are stored in magazine 200 by attaching holder 50 to sheet 40. Magazine 200 is a box-shaped case in which one of the side walls has been removed to form opening 230. A number of rails 220 for storing semiconductor wafers 30 are provided inside side walls 210 that sandwich opening 230 on both the left and right sides. A handle is also provided on the top of magazine 200. Note that magazine 200 is not limited to the example shown in FIG. 6, and may be, for example, a type in which semiconductor wafers 30 are placed vertically.

[0019] 5 is a plan view showing a state in which holder 50 is attached to sheet 40 according to embodiment 1. An annular holder 50 is attached to the outer periphery of the surface of sheet 40 to which semiconductor wafer 30 is adhered, surrounding semiconductor wafer 30. The outer periphery of the ring of holder 50 is larger than that of sheet 40, so that sheet 40 does not protrude outside the ring of holder 50.

[0020] A pair of opposing side portions 51 on the outer periphery of holder 50 are flat. By placing the pair of flat side portions 51 on rails 220, semiconductor wafers 30 can be stored in magazine 200. Note that, although the pair of side portions 51 are provided in positions that form 90 degrees with respect to orientation flat 33 of semiconductor wafer 30 here, the positions of side portions 51 are not limited.

[0021] Furthermore, notches 52 are provided in an area of ​​the outer periphery of holder 50 that is different from the pair of side portions 51. Notches 52 are portions that receive stoppers 240 of magazine 200 when semiconductor wafers 30 are stored in magazine 200. Note that although two notches 52 are provided here, it is sufficient for there to be one or more notches 52. Furthermore, the positions at which notches 52 are provided are not limited to the example shown in the figure, and they may be provided according to the positions of stoppers 240 of magazine 200.

[0022] 6 is a cross-sectional view of radiation irradiation apparatus 100 to which semiconductor wafer 30 according to embodiment 1 is attached. Diced semiconductor wafer 30 is attached to sheet 40 and is attached to radiation irradiation apparatus 100. Holder 50 is attached to the surface of sheet 40.

[0023] The radiation irradiation device 100 has a light source 80 that emits radiation, a mask 60, and a base 70. The base 70 is cylindrical with one bottom surface open, and an opening is formed in the center of the other bottom surface. An annular mask 60 is placed on the outer periphery of the bottom surface with the opening, and a sheet 40 and a semiconductor wafer 30 attached to the sheet 40 are attached on top of the mask 60. The light source 80 is a radiation source that irradiates radiation onto the back surface of the sheet 40. The radiation is, for example, ultraviolet light, but is not limited to this.

[0024] The mask 60 shields radiation from the light source 80 from the area of ​​the sheet 40 that will be adhered to the non-rectangular chip 31. Therefore, the adhesive strength is not reduced in the area of ​​the sheet 40 that will be adhered to the non-rectangular chip 31. As a result, the non-rectangular chip 31 can be attached to the sheet 40 with strong adhesive strength. On the other hand, the mask 60 has an opening 2 that exposes only the active area 1 of the semiconductor wafer 30, and does not shield radiation from the area of ​​the sheet 40 that will be adhered to the semiconductor chip 32. Therefore, the adhesive strength is reduced in the area of ​​the sheet 40 that will be adhered to the semiconductor chip 32.

[0025] In this embodiment, the sheet 40 is sandwiched between the mask 60 and the holder 50. This allows the sheet 40 to be in close contact with the mask 60. Because the distance between the sheet 40 and the mask 60 is short, radiation that passes through the openings 2 of the mask 60 reaches the sheet 40 without being scattered. This prevents unintended areas of the sheet 40 from being irradiated by scattered light. Furthermore, in this embodiment, the sheet 40 sandwiched between the holder 50 and the mask 60 can be attached to the radiation irradiation device 100, and these attachments can be completed simultaneously.

[0026] FIG. 7 is a plan view of a mask 60 according to the first embodiment. The mask 60 has an opening 2 of the same size and shape as the effective area 1 of the semiconductor wafer 30. As described above, the periphery of the effective area 1 of the semiconductor wafer 30 is partially stepped, and the opening 2 of the mask 60 is also partially stepped accordingly. However, the shape of the opening 2 does not necessarily have to expose only the effective area 1. That is, the opening 2 may also expose a portion of the area of ​​the semiconductor wafer 30 that includes the non-rectangular chips 31. While it is desirable for the opening 2 to expose the entire effective area 1, it may also expose only a portion. The thickness of the mask is, for example, approximately 1 to 4 mm, but this is merely an example and is not limiting. The mask 60 may be made of a material such as stainless steel, aluminum, or resin, as long as it is a material that does not transmit radiation.

[0027] 5, and the outer shape of the mask 60 is the same as the outer shape of the ring of the holder 50 in plan view. That is, the mask 60 also has a pair of flat side portions 61 on its outer periphery, just like the holder 50. The positions of the pair of side portions 61 on the mask 60, just like the holder 50, are at 90 degrees with respect to the orientation flat 33 (not shown) of the semiconductor wafer 30. Similarly, the mask 60 also has a notch 62 on its outer periphery, just like the holder 50. The position of the notch 62 on the mask 60 is the same as the position of the notch 52 on the holder 50.

[0028] 8 is a top view showing a state in which semiconductor wafers 30 and masks 60 according to the first embodiment are stored in the same magazine 200. By making the masks 60 and holders 50 the same size in a plan view, the masks 60 can also be stored in the same magazine that stores semiconductor wafers 30. That is, by providing a pair of side portions 61 on the outer periphery of the mask 60, the masks 60 can be placed on rails 220 of the magazine 200 in the same way as the holders 50. Furthermore, by providing notches 62 on the outer periphery of the mask 60 at the same position and size as the holders 50, the masks 60 can be fixed by stoppers 240 of the magazine 200 at the same time as the holders 50.

[0029] Stoppers 211 that perpendicularly intersect with the rails 220 are provided on the inside of the side wall 210 of the magazine 200. A pair of side portions 61 of the mask 60 and a pair of side portions 51 of the holder 50 are fixed onto the rails 220 by the stoppers 211.

[0030] As described above, in this embodiment, the mask 60 that shields radiation has the same size in plan view as the annular holder 50 attached to the sheet 40 that is adhered to the semiconductor wafer 30. Therefore, the mask 60 can be stored in the same magazine 200 as the semiconductor wafer 30. This allows the semiconductor wafer 30 and the mask 60 to be managed in association with each other.

[0031] Even if the semiconductor wafers 30 and the masks 60 are stored in different magazines 200, the AMR that transports the magazines 200 can be unified, so the semiconductor wafers 30 and the masks 60 can be managed in association with each other.

[0032] Embodiment 2 In this embodiment, the semiconductor wafer 30 and the mask 60 are aligned before the sheet 40 is irradiated with radiation. Here, the changes from the first embodiment will be described.

[0033] FIG. 9 is a cross-sectional view of a radiation irradiation apparatus 100 according to the second embodiment, to which a semiconductor wafer 30 is attached. In this embodiment, the semiconductor wafer 30 is attached via a holder 50 to a holder fixing table 73 provided on the inner wall of a base 70. The outer periphery of the holder 50 is placed on the holder fixing table 73. A groove 71 extending horizontally to the bottom surface of the cylinder is formed on the inner wall of the cylindrical base 70, and a mask fixing table 72 for placing or fixing a mask 60 is attached in the groove 71. The mask fixing table 72 has a built-in servo motor and moves within the groove 71 in the depth and width directions of the groove 71, thereby aligning the opening 2 of the mask 60 with the effective area 1 of the semiconductor wafer 30. This ensures that radiation is irradiated only to the area of ​​the sheet 40 that is bonded to the semiconductor chip 32, achieving a superior effect to that of the first embodiment.

[0034] <Modification of the Second Embodiment> Note that alignment may be performed by moving the semiconductor wafer 30 attached to the sheet 40 instead of the mask 60. Fig. 10 shows a modified example of the radiation irradiation apparatus 100 shown in Fig. 9. In this example, a holder fixing table 73 has a built-in servo motor, and the holder fixing table 73 moves the inner wall of the base 70 vertically or horizontally to align the effective area 1 of the semiconductor wafer 30 with the opening 2 of the mask 60. This provides the same effect as in the second embodiment.

[0035] Embodiment 3 In this embodiment, the alignment of the mask 60 described in the second embodiment is performed based on an image captured by a camera. Here, the changes from the second embodiment will be described.

[0036] 11 is a cross-sectional view of a radiation irradiation device 100 equipped with a semiconductor wafer 30 according to the third embodiment. The radiation irradiation device 100 has a first camera 91 that captures an image of the boundary of the effective area 1 from above the semiconductor wafer 30, and a second camera 92 that captures an image of the edge of the opening 2 in the mask 60 from a direction facing the first camera 91. The first camera 91 and the second camera 92 are installed on the same axis. In alignment, the boundary of the effective area 1 is aligned with the edge of the opening 2 in the mask 60 based on the images captured by the first camera 91 and the second camera 92. Since adjustment is performed based on the images, alignment accuracy can be improved compared to the second embodiment.

[0037] It should be noted that the first camera 91 and the second camera 92 do not necessarily have to be installed on the same axis. Also, if the first camera 91 can capture an image of the edge of the opening 2 in the mask 60 through the semiconductor wafer 30 and the sheet 40, the second camera 92 may be omitted. Similarly, if the second camera 92 can capture an image of the boundary of the effective area 1 of the semiconductor wafer 30 through the sheet 40, the first camera 91 may be omitted.

[0038] <Modification of the Third Embodiment> Fig. 12 shows a modification of the radiation irradiation apparatus 100 of Fig. 11. As in the modification of the second embodiment, the semiconductor wafer 30 attached to the sheet 40 may be moved. This provides the same effect as in the third embodiment.

[0039] Embodiment 4 In this embodiment, radiation is irradiated onto the sheet 40 in a vacuum environment. FIG. 13 is a cross-sectional view of a radiation irradiation apparatus 100 according to embodiment 4, to which a semiconductor wafer 30 is attached. In this embodiment, the radiation irradiation apparatus 100 according to embodiment 1 is disposed within a vacuum chamber 110. That is, the vacuum chamber 110 contains a light source 80, a mask 60, a base 70, and a semiconductor wafer 30. The vacuum chamber 110 is connected to an external vacuum pump or the like via an exhaust valve 111, allowing the interior to be evacuated. The pressure during vacuum is, for example, -100 to -50 Pa, but is not limited thereto.

[0040] 14 is a diagram illustrating a defect that occurs when oxygen gets into the adhesive layer 41 of the sheet 40 according to the fourth embodiment. The adhesive layer 41 of the sheet 40 is hardened by radiation and its adhesive strength is reduced. However, if oxygen gets into the adhesive layer 41 due to incisions made in the adhesive layer 41 during dicing, the adhesive layer 41 and the oxygen will react when the adhesive layer 41 is irradiated with radiation. The adhesive layer 41 that has reacted with oxygen will adhere to the side of the semiconductor chip 32, which can cause errors when the semiconductor chip 32 is peeled off from the sheet 40 and picked up in a later process.

[0041] In this embodiment, by irradiating the sheet 40 with radiation in a vacuum environment, it is possible to prevent oxygen from entering the adhesive layer 41 and prevent the adhesive layer 41 from adhering to the side surface of the semiconductor chip 32.

[0042] Fifth embodiment In this embodiment, the size of the opening 2 in the mask 60 is variable. Here, the changes from the second embodiment will be described.

[0043] FIG. 15 is a cross-sectional view of a radiation irradiation apparatus 100 having a semiconductor wafer 30 mounted thereon according to the fifth embodiment. In this embodiment, a mask 60 is fixed to the upper surface of a mask fixing table 72. The mask 60 may be fixed to the mask fixing table 72 with screws or the like. The mask fixing table 72 is provided on the inner wall of a cylindrical base 70, and rotates in a plane horizontal to the bottom surface of the cylinder, thereby rotating the mask 60. The mask 60 has a slit-shaped opening 2 extending from the outer periphery to the center. A shutter 120 is attached to the mask fixing table 72 and rotates together with the mask 60. The shutter 120 adjusts the size of the opening 2 by moving over the opening 2.

[0044] The manufacturing process of this embodiment is as follows. First, the size of the opening 2 in the mask 60 is adjusted so as to expose an area of ​​the sheet 40 to be bonded to the semiconductor chip 32 while simultaneously shielding an area of ​​the sheet 40 to be bonded to the non-rectangular chip 31 (Step 1). The size of the opening 2 is adjusted by moving the shutter 120 from the outside of the opening 2 to the center. Next, radiation is irradiated onto the back surface of the sheet 40 (Step 2). After that, the mask 60 is rotated, and the opening 2 is moved to an area of ​​the sheet 40 that has not been irradiated (Step 3). Steps 1 to 3 are repeated until the entire area of ​​the sheet to be bonded to the semiconductor chip 32 has been irradiated with radiation. That is, Steps 1 to 3 are repeated until the mask 60 has rotated once, thereby completing irradiation so as to cover the entire effective area 1.

[0045] In the third step, the mask 60 does not necessarily have to be rotated, and the opening 2 may be moved by moving the mask 60 horizontally relative to the bottom surface of the cylinder of the base 70. In addition, in the third step, the semiconductor wafer 30 bonded to the sheet 40 may be moved instead of the mask 60.

[0046] 16 is a plan view of a mask 60 according to the fifth embodiment. From the viewpoint of covering the effective area 1 of a semiconductor wafer 30 of a typical size, it is desirable that the size of the mask 60 in a plan view is approximately 140 to 350 mm, and the thickness is 10 to 50 mm. Note that although the shape of the mask 60 here is disk-shaped, it may have any outer shape as long as it can be fixed to the mask fixing base 72, for example, a rectangular shape. Furthermore, the opening 2 of the mask 60 may have any shape as long as it can be formed by the shutter 120.

[0047] In this embodiment, a mask 60 with a variable size of opening 2 is used to irradiate radiation onto sheet 40 to which semiconductor wafer 30 is bonded. Therefore, one mask 60 can be used to handle a plurality of semiconductor wafers 30 with different sizes and shapes of effective areas 1, making management of semiconductor wafers 30 and mask 60 even easier than in the first to fourth embodiments.

[0048] Sixth embodiment In this embodiment, a mask for blocking radiation is formed on the sheet 40 itself. Here, the changes from the first embodiment will be described.

[0049] FIG. 17 is a diagram showing the back surface of sheet 40 according to embodiment 6. This figure shows a state in which holder 50 is attached to the front surface of sheet 40. A radiation shielding agent 43 is applied to the area of ​​substrate 42, which is the back surface of sheet 40, that will be attached to non-rectangular chip 31. The shielding agent 43 is a material that has the property of absorbing or scattering radiation, and examples of such materials include acrylic resin and light stabilizers. The shielding agent 43 may be printed on substrate 42 of sheet 40, or may be applied using a dispenser or the like.

[0050] In this embodiment, the sheet 40 and the mask are integrated by applying a shielding agent 43 to the rear surface of the sheet 40 to which the semiconductor wafer 30 is adhered. This allows the semiconductor wafer 30 and the mask to be managed in association with each other.

[0051] The present disclosure is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the present disclosure. Furthermore, the embodiments and modifications may be implemented in appropriate combinations, in which case the combined effects can be obtained.

[0052] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) Attaching a semiconductor wafer to a surface of a sheet whose adhesive strength is reduced by radiation; attaching an annular holder to the outer periphery of the front surface of the sheet so as to surround the semiconductor wafer; dicing the semiconductor wafer into rectangular semiconductor chips; irradiating the back surface of the sheet with radiation after shielding, with a mask arranged on the back surface side of the sheet, at least a part of an area of ​​the sheet that will be adhered to a non-rectangular chip generated on the outer periphery of the semiconductor wafer by dicing; Including, The method for manufacturing a semiconductor device, wherein the mask has the same size as the holder in a plan view. (Appendix 2) 2. The method for manufacturing a semiconductor device according to claim 1, wherein the mask has the same outer shape as the holder in a plan view. (Appendix 3) A pair of opposing side portions on the outer periphery of the holder and the mask are flat, 3. The method for manufacturing a semiconductor device according to claim 2, wherein the semiconductor wafer is stored in a magazine by placing the side portion on a rail. (Appendix 4) The holder and the mask have notches on their outer peripheries, 4. The method for manufacturing a semiconductor device according to claim 2, wherein the notch is a portion that receives a stopper of the magazine when the semiconductor wafer is stored in the magazine. (Appendix 5) 5. The method for manufacturing a semiconductor device according to any one of claims 1 to 4, further comprising aligning the semiconductor wafer and the mask by moving the semiconductor wafer or the mask attached to the sheet using a servo motor before irradiating the radiation. (Appendix 6) The method for manufacturing a semiconductor device described in Appendix 5, wherein the mask has an opening of the same size and shape as an effective area of ​​the semiconductor wafer, which is an area that does not include the non-rectangular chip, and the alignment aligns the effective area and the opening based on images captured by a first camera that captures an image of the boundary of the effective area from above the semiconductor wafer and a second camera that captures an image of the edge of the opening from a direction facing the first camera. (Appendix 7) a first step of adjusting the size of the opening of the mask by a shutter so that an area of ​​the sheet to be adhered to the semiconductor chip is exposed and an area of ​​the sheet to be adhered to the non-rectangular chip is shielded; a second step of irradiating the back surface of the sheet with the radiation; a third step of moving the opening to an area of ​​the sheet that has not been irradiated with radiation; Including, 7. The method for manufacturing a semiconductor device according to any one of claims 1 to 6, wherein the first to third steps are repeated until the radiation is irradiated onto the entire area of ​​the sheet that is to be attached to the semiconductor chip. (Appendix 8) 8. The method for manufacturing a semiconductor device according to claim 7, wherein the opening in the mask is a slit-shaped opening extending from the outer periphery to the center of the mask. (Appendix 9) 9. The method for manufacturing a semiconductor device according to claim 1, wherein the sheet is in a vacuum environment when the radiation is irradiated. (Appendix 10) 5. The method for manufacturing a semiconductor device according to claim 1, wherein the sheet is sandwiched between the mask and the holder when the radiation is applied. (Appendix 11) A sheet for semiconductor wafers, having an adhesive layer on its surface whose adhesive strength is reduced by radiation, and a mask of a shielding agent that absorbs or scatters the radiation on its back surface. [Explanation of symbols]

[0053] 1 active area, 2 opening, 30 semiconductor wafer, 31 non-rectangular chip, 32 semiconductor chip, 33 orientation flat, 40 sheet, 41 adhesive layer, 42 substrate, 43 shielding agent, 50 holder, 51 side portion, 52 notch, 60 mask, 61 side portion, 62 notch, 70 base, 71 groove, 72 mask fixing base, 73 holder fixing base, 80 light source, 91 first camera, 92 second camera, 100 radiation irradiation device, 110 vacuum chamber, 111 exhaust valve, 120 shutter, 200 magazine, 210 side wall, 211 stopper, 220 rail, 230 opening, 240 stopper

Claims

1. Attaching a semiconductor wafer to a surface of a sheet whose adhesive strength is reduced by radiation; attaching an annular holder to the outer periphery of the front surface of the sheet so as to surround the semiconductor wafer; dicing the semiconductor wafer into rectangular semiconductor chips; irradiating the back surface of the sheet with radiation after shielding, with a mask arranged on the back surface side of the sheet, at least a part of an area of ​​the sheet that will be adhered to a non-rectangular chip generated on the outer periphery of the semiconductor wafer by dicing; Including, The method for manufacturing a semiconductor device, wherein the mask has the same size as the holder in a plan view.

2. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the mask has the same outer shape as the holder in a plan view.

3. A pair of opposing side portions on the outer periphery of the holder and the mask are flat, 3. The method for manufacturing a semiconductor device according to claim 2, wherein the semiconductor wafer is stored in the magazine by placing the side portion on a rail.

4. The holder and the mask have notches on their outer peripheries, 4. The method for manufacturing a semiconductor device according to claim 3, wherein the notch is a portion that receives a stopper of the magazine when the semiconductor wafer is stored in the magazine.

5. 5. The method for manufacturing a semiconductor device according to claim 1, further comprising: aligning the semiconductor wafer and the mask by moving the semiconductor wafer or the mask attached to the sheet using a servo motor before irradiating the radiation.

6. 6. The method for manufacturing a semiconductor device according to claim 5, wherein the mask has an opening of the same size and shape as an effective area of ​​the semiconductor wafer, which is an area that does not include the non-rectangular chip, and the alignment involves aligning the effective area and the opening based on images captured by a first camera that captures an image of the boundary of the effective area from above the semiconductor wafer and a second camera that captures an image of the edge of the opening from a direction facing the first camera.

7. a first step of adjusting the size of an opening in the mask by a shutter so that an area of ​​the sheet to be adhered to the semiconductor chip is exposed and an area of ​​the sheet to be adhered to the non-rectangular chip is shielded; a second step of irradiating the back surface of the sheet with the radiation; a third step of moving the opening to an area of ​​the sheet that has not been irradiated with radiation; Including, 5. The method for manufacturing a semiconductor device according to claim 1, wherein the first to third steps are repeated until the radiation is irradiated onto the entire area of ​​the sheet that is to be attached to the semiconductor chip.

8. 8. The method for manufacturing a semiconductor device according to claim 7, wherein the opening in the mask is a slit-shaped opening extending from the outer periphery to the center of the mask.

9. The method for manufacturing a semiconductor device according to claim 1 , wherein the sheet is in a vacuum environment when the radiation is irradiated.

10. The method for manufacturing a semiconductor device according to claim 1 , wherein the sheet is sandwiched between the mask and the holder when the radiation is applied.

11. A sheet for semiconductor wafers, having an adhesive layer on its surface whose adhesive strength is reduced by radiation, and a mask of a shielding agent that absorbs or scatters the radiation on its back surface.

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