Support sheet, composite sheet for forming protective film, and method for manufacturing the device

Abstract

To provide a support sheet capable of achieving both poor feeding of a sheet and recognizability of laser marking when observed through a base material, a protective film forming composite sheet including the support sheet and a protective film forming film, and a method for manufacturing an apparatus such as a semiconductor apparatus.SOLUTION: A support sheet includes a base material and an adhesive layer formed on one main surface of the base material, and in the base material, a rectangular area of 4.91 mm×4.90 mm on the main surface on which the adhesive layer is not formed has an arithmetic mean height Sa1 of more than 0.50 μm and a gloss value of 20 or more at an incident angle of 60° on the main surface on which the adhesive layer is not formed. Moreover, a protective film forming composite sheet is provided with this support sheet and a protective film forming film.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a support sheet, a composite sheet for forming a protective film, and a method for manufacturing a device, and more particularly to a support sheet used to fix a workpiece such as a semiconductor wafer when processing the workpiece, a composite sheet for forming a protective film having the support sheet and a protective film-forming film suitable for protecting a workpiece such as a semiconductor wafer or a processed product such as a semiconductor chip obtained by processing the workpiece, and a method for manufacturing a device such as a semiconductor chip. [Background technology]

[0002] In recent years, semiconductor devices have been manufactured using a mounting method known as the face-down method. In the face-down method, a semiconductor chip having electrodes such as bumps on its circuit surface is used, and the electrodes are bonded to a substrate. As a result, the back surface of the semiconductor chip, opposite the circuit surface, may be exposed.

[0003] A protective film made of an organic resin is formed on the back surface of the exposed semiconductor chip, and the semiconductor chip with such a protective film is sometimes incorporated into a semiconductor device. The protective film is used to prevent chipping, such as cracking or chipping, in the semiconductor chip during the dicing process and subsequent steps.

[0004] To form such a protective film, a composite sheet for forming a protective film is used, which comprises a protective film-forming film (protective film-forming layer) on a support sheet. As the support sheet, for example, a laminated sheet in which an adhesive layer or the like is laminated on a resin substrate is used. Furthermore, the support sheet alone can function as a dicing sheet for semiconductor wafers or the like. In the composite sheet for forming a protective film, the protective film-forming film has the protective film-forming ability, and the support sheet can also function as a dicing sheet, so it can be said to be a sheet in which the protective film-forming film and the dicing sheet are integrated.

[0005] In the substrate used for the support sheet, the surface that comes into contact with other members usually has an uneven shape. This is because, if such an uneven shape is not present, when the support sheet is unwound from a roll on which it is wound, the substrate and the release film formed on the adhesive layer will stick together and cause blocking, making it difficult to unwind the support sheet from the roll. Therefore, if the surface of the substrate that comes into contact with other members has an uneven shape, the area of the contact surface will be reduced, thereby suppressing blocking.

[0006] The same is true for a composite sheet for forming a protective film in which a protective film-forming film is formed on the pressure-sensitive adhesive layer of a support sheet. That is, when the composite sheet for forming a protective film is unwound from the roll on which it is wound, the substrate and the release film formed on the protective film-forming film stick to each other and cause blocking, so the surface of the substrate that comes into contact with the release film has an uneven shape.

[0007] On the other hand, in order to identify the semiconductor wafer or semiconductor chip, marks, letters, etc. are marked on the surface of the semiconductor wafer or the protective film-forming film by, for example, laser marking. Such laser marking is performed by irradiating laser light from the side of the substrate provided in the support sheet on which the adhesive layer is not formed. Therefore, if the surface on which the adhesive layer is not formed has an uneven shape, the laser light is scattered or diffused on that surface, which may make the marking unclear.

[0008] Patent Document 1 describes a support sheet including a substrate and a pressure-sensitive adhesive layer laminated on the substrate, or a composite sheet for forming a protective film including a protective film-forming film on the pressure-sensitive adhesive layer of the support sheet, in which the surface on the side on which the pressure-sensitive adhesive layer is formed has a surface roughness (Ra) of 0.4 μm or less, and the surface roughness (Ra) of the substrate on the side opposite the side on which the pressure-sensitive adhesive layer is formed is greater than the surface roughness on the side on which the pressure-sensitive adhesive layer is formed, and is 0.053 to 0.48 μm. It also describes that this support sheet or composite sheet for forming a protective film can suppress blocking while improving the recognizability of laser marking. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2017 / 163971 Summary of the Invention [Problem to be solved by the invention]

[0010] However, even with the support sheet or composite sheet for forming a protective film described in Patent Document 1, there was a problem in that it was difficult to more stably achieve both poor sheet feeding due to blocking and the visibility of the laser marking when observed through the substrate.

[0011] The present invention has been made in consideration of the above-described situation, and aims to provide a support sheet that can achieve both poor sheet feeding and the recognizability of laser marking when observed through the substrate, a composite sheet for forming a protective film that includes the support sheet and a protective film-forming film, and a method for manufacturing devices such as semiconductor devices. [Means for solving the problem]

[0012] The aspects of the present invention are as follows. [1] A substrate and a pressure-sensitive adhesive layer formed on one main surface of the substrate, In the base material, the arithmetic mean height Sa1 of a 4.91 mm × 4.90 mm square region on the main surface on which the pressure-sensitive adhesive layer is not formed is greater than 0.50 μm, The support sheet has a gloss value of 20 or more at an incident angle of 60° on the main surface on which the pressure-sensitive adhesive layer is not formed. [2] A 4.91 mm × 4.90 mm square area on the main surface on which the adhesive layer is not formed is a large area obtained by combining 300 narrow areas, each of which is a 0.36 mm × 0.27 mm square area; The support sheet according to [1], wherein Sa2 is 0.43 μm or less when the average of the 20 smallest arithmetic mean heights of the narrow regions is Sa2. [3] The support sheet according to [1] or [2], wherein the ratio of Sa1 to Sa2, Sa1 / Sa2, is 1.40 or more. [4] The support sheet according to any one of [1] to [3], wherein no other layer is formed on the main surface on which the pressure-sensitive adhesive layer is not formed. [5] A composite sheet for forming a protective film, comprising the support sheet according to any one of [1] to [4] and a protective film-forming film formed on the adhesive layer of the support sheet. [6] A kit comprising the support sheet according to any one of [1] to [4] and a protective film-forming film to be attached to the surface of the adhesive layer of the support sheet. [7] A step of unwinding and unrolling the support sheet according to any one of [1] to [4] wound in a roll; A step of attaching the unwound support sheet to a workpiece; A step of laser marking a workpiece; and a step of processing the workpiece to obtain a processed product of the workpiece. [8] A step of unwinding and unwinding the composite sheet for forming a protective film according to [5] wound in a roll; A step of attaching the protective film-forming film of the unwound protective film-forming composite sheet to the back surface of the workpiece; A step of converting the attached protective film-forming film into a protective film; A step of laser marking the protective film or the protective film-forming film; The method for manufacturing the device includes a step of dividing a workpiece having a protective film or a protective film-forming film on its back surface into individual pieces to obtain a plurality of workpieces with the protective film or the protective film-forming film. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a support sheet that can achieve both poor sheet unwinding and the recognizability of laser marking when observed through a substrate, a composite sheet for forming a protective film that includes the support sheet and a protective film-forming film, and a method for manufacturing devices such as semiconductor devices. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view of an example of a support sheet according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the composite sheet for forming a protective film according to this embodiment. [Figure 3] FIG. 3 is a schematic diagram illustrating the surface properties of the main surface of the substrate of the support sheet according to this embodiment on which the pressure-sensitive adhesive layer is not formed. [Figure 4] FIG. 4 is an enlarged schematic view of part IV in FIG. [Figure 5] FIG. 5 is a cross-sectional schematic diagram of an example of a chip having a protective film obtained by forming a protective film from a protective film-forming film. [Figure 6] FIG. 6 is a cross-sectional view illustrating a process of attaching the composite sheet for forming a protective film according to this embodiment to a wafer. [Figure 7] FIG. 7 is a cross-sectional schematic view of another example of the composite sheet for forming a protective film according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described in detail below based on specific embodiments with reference to the accompanying drawings. First, the main terms used in this specification will be explained.

[0016] The workpiece is a plate-like body to which the support sheet or the composite sheet for forming a protective film according to this embodiment is attached and processed. Examples of the workpiece include wafers and panels. Specifically, examples include semiconductor wafers and semiconductor panels. Examples of processed products of the workpiece include chips obtained by dividing a wafer. Specifically, examples include semiconductor chips obtained by dividing a semiconductor wafer. In this case, the protective film is formed on the back side of the wafer and the chip.

[0017] The "front surface" of a workpiece such as a wafer refers to the surface on which circuits, bumps, and other convex electrodes are formed, while the "back surface" refers to the surface on which circuits, electrodes (for example, bumps and other convex electrodes) are not formed.

[0018] Wafer singulation refers to dividing the wafer into individual circuits to obtain chips.

[0019] In this specification, for example, "(meth)acrylate" is used as a term indicating both "acrylate" and "methacrylate," and the same applies to other similar terms.

[0020] "Energy rays" refers to ultraviolet rays, electron beams, etc., and is preferably ultraviolet rays.

[0021] The release film is a film that supports the pressure-sensitive adhesive layer or the protective film-forming film in a releasable manner. The term "film" is not limited to a specific thickness, and is used to include a sheet.

[0022] The mass ratios in the descriptions of compositions such as the composition for the protective film-forming film are based on the active ingredient (solid content), and do not include the solvent unless otherwise specified.

[0023] (1. Support sheet) The support sheet according to this embodiment is used to fix a workpiece when processing the workpiece. For example, such a sheet is used to attach to a workpiece when cutting the workpiece to obtain multiple processed workpieces. Therefore, the support sheet according to this embodiment can be used as a dicing sheet. Furthermore, like the composite sheet for forming a protective film described below, a functional layer that imparts predetermined performance to the workpiece or a processed product of the workpiece may be formed on the support sheet.

[0024] 1, the support sheet 1 according to this embodiment has a base material 2 and a pressure-sensitive adhesive layer 3 formed on one main surface 2a of the base material. In this embodiment, it is preferable that no other layer is formed on the main surface 2b of the base material 2 on which the pressure-sensitive adhesive layer is not formed. In other words, it is preferable that the main surface 2b of the base material 2 on which the pressure-sensitive adhesive layer is not formed is an exposed surface that is exposed to the outside.

[0025] The support sheet according to the present embodiment may be in the form of a long sheet whose longitudinal length is significantly longer than its lateral length, or may be in the form of a sheet roll in which such a long sheet is wound up.

[0026] When the support sheet is wound up, a release film is preferably formed on the surface 3a of the pressure-sensitive adhesive layer 3. By forming a release film on the surface of the pressure-sensitive adhesive layer, even when the support sheet is wound up into a sheet roll, it is possible to prevent the substrate, the surface 3a of the pressure-sensitive adhesive layer, and the main surface 2b of the substrate on which the pressure-sensitive adhesive layer is not formed from sticking to each other.

[0027] (2. Composite sheet for forming protective film) The composite sheet for forming a protective film according to this embodiment is used to protect the workpiece or a processed product of the workpiece by attaching the protective film-forming film to the workpiece and turning the protective film-forming film into a protective film.

[0028] As shown in Fig. 2, the composite sheet 10 for forming a protective film according to this embodiment has a protective film-forming film 4, a support sheet 1 that supports the protective film-forming film 4, and a jig adhesive layer 5 for adhering the composite sheet 10 for forming a protective film to a jig such as a ring frame. The support sheet 1 is the same as the support sheet described in (1), and has a base material 2 and an adhesive layer 3 formed on one main surface 2a of the base material 2. The protective film-forming film 4 is formed on the surface 3a of the adhesive layer 3. The jig adhesive layer 5 is formed on the peripheral portion of the main surface 4a of the protective film-forming film 4.

[0029] As in (1), in this embodiment, it is preferable that no other layer is formed on the main surface 2b of the base material 2 on which the pressure-sensitive adhesive layer is not formed. In other words, it is preferable that the main surface 2b of the base material 2 on which the pressure-sensitive adhesive layer is not formed is an exposed surface that is exposed to the outside.

[0030] Similarly to (1), the composite sheet for forming a protective film according to this embodiment may be in the form of a long sheet whose longitudinal length is significantly longer than its lateral length, or may be in the form of a sheet roll in which such a long sheet is wound up.

[0031] When the composite sheet for forming a protective film is wound up, it is preferable that a release film be formed on the surface 4a of the protective film-forming film 4 and the surface of the jig pressure-sensitive adhesive layer 5. By forming a release film on the surface of the pressure-sensitive adhesive layer, even when the composite sheet for forming a protective film is wound up into a sheet roll, it is possible to prevent the surface 4a of the protective film-forming film 4 and the surface of the jig pressure-sensitive adhesive layer 5 from sticking to the main surface 2b of the base material on which the pressure-sensitive adhesive layer is not formed.

[0032] However, when a roll-shaped composite sheet for forming a protective film with a release film is unwound and unwound to be attached to a workpiece, the composite sheet for forming a protective film located immediately below the release film in the radial direction may stick to the release film formed on the surface of the protective film-forming film, making it impossible to unwind the composite sheet for forming a protective film.Similarly, when a roll-shaped support sheet with a release film is unwound and unwound to be attached to a workpiece, the support sheet located immediately below the release film in the radial direction may stick to the release film formed on the surface of the adhesive layer, making it impossible to unwind the support sheet.

[0033] To prevent such poor feeding, it is preferable that the main surface 2b of the substrate of the support sheet and the composite sheet for forming a protective film, on which the adhesive layer is not formed, has slight irregularities. By forming such irregularities, the contact area between the main surface 2b of the substrate and the release film is reduced, and the support sheet or the composite sheet for forming a protective film is less likely to stick to the release film.

[0034] Incidentally, wafers as workpieces or chips obtained by dividing wafers are sometimes marked to improve their identifiability. In this case, the marking may be made directly on the wafer or chip, or on a protective film attached to the wafer or chip. In either case, the marking is usually made by irradiating the wafer or chip with a laser beam (laser marking).

[0035] When laser marking is performed, the wafer or chip is located on the surface 3a of the pressure-sensitive adhesive layer shown in Fig. 1 or on the main surface 4a of the protective film-forming film shown in Fig. 2, so the laser light enters from the main surface 2b side of the substrate, passes through the support sheet 1, and reaches the wafer or chip. At this time, if the main surface 2b of the substrate has irregularities, the laser light may be scattered or diffused, resulting in unclear marking.

[0036] Furthermore, in order to confirm the markings applied to the wafer or chip, the markings can be observed either after peeling off the support sheet or through the support sheet. When observing the markings through the support sheet, the markings are observed from the main surface 2b side of the substrate using a microscope or the like, and if the observation light is scattered or diffusely reflected, the markings may not be clearly recognized.

[0037] Therefore, the surface condition of the side of the base material of the support sheet on which the pressure-sensitive adhesive layer is not formed affects the payout property of the support sheet or the composite sheet for forming a protective film and the recognizability of the laser marking, and these are contradictory properties. In other words, it is very difficult to achieve both of these properties at the same time.

[0038] Therefore, in this embodiment, both payout performance and laser marking visibility are achieved by controlling the surface properties of the base material of the support sheet as follows. Below, the components of the support sheet and the composite sheet for forming a protective film according to this embodiment will be described in detail.

[0039] (3.Base material) The substrate of the support sheet supports the workpiece via the adhesive layer during processing of the workpiece. The substrate may be made of a single-layer film made of one resin film, or may be made of a multi-layer film made of multiple resin films laminated together.

[0040] However, it is preferable that no other layer is formed on the main surface of the substrate opposite to the main surface on which the pressure-sensitive adhesive layer is formed (the main surface on which the pressure-sensitive adhesive layer is not formed).Therefore, it is preferable that the main surface of the substrate on which the pressure-sensitive adhesive layer is not formed is an exposed surface that is exposed to the outside.

[0041] Forming such other layers involves the problem of increased costs. There is also the risk that components contained in the other layers may migrate and adhere to the surface in contact with the other layers. Particularly when the support sheet or the composite sheet for forming a protective film is in the form of a sheet roll, the other layers will come into contact with the back surface of the release film, making the above-mentioned risks highly likely to become apparent.

[0042] The thickness of the substrate is not particularly limited as long as it can function appropriately in each process in which the composite sheet for forming a protective film is used, and is preferably in the range of 20 to 200 μm, more preferably 40 to 170 μm, and particularly preferably 50 to 140 μm.

[0043] (3.1 Gloss of the substrate) In this embodiment, the gloss value at an incident angle of 60° on the main surface of the substrate opposite to the main surface on which the pressure-sensitive adhesive layer is formed (main surface 2b in FIGS. 1 and 2) is 20 or more.

[0044] By keeping the gloss value at an incident angle of 60° within the above range, scattering or diffuse reflection of the observation light is suppressed even when the marking is observed through the support sheet, so that the marking can be clearly recognized.

[0045] The gloss value at an incident angle of 60° is preferably 25 or more, more preferably 35 or more, and even more preferably 45 or more. On the other hand, the upper limit of the gloss value is not particularly limited, but is, for example, preferably 140 or less, more preferably 110 or less, and even more preferably 80 or less.

[0046] The gloss value at an incident angle of 60° is measured in accordance with JIS Z 8741. That is, the measurement is performed in the same manner as the measurement method specified in JIS Z 8741, but the measurement conditions may be different. The specific measurement method will be described in the examples.

[0047] (3.2 Surface properties of substrate) In this embodiment, the surface properties of the main surface (main surface on which no adhesive layer is formed: main surface 2b in Figures 1 and 2) opposite to the main surface (one main surface) on which the adhesive layer of the substrate is formed are controlled to a predetermined shape.

[0048] Specifically, if the arithmetic mean height of a 4.91 mm x 4.90 mm square area on the main surface of the substrate where the adhesive layer is not formed is Sa1, Sa1 is greater than 0.50 μm. Arithmetic mean height of the surface is one of the surface roughness parameters specified in ISO 25178, and is the average absolute value of the peak height and valley depth on the measured surface. Sa1 indicates the average surface roughness over the entire measured surface, with the influence of localized irregularities suppressed.

[0049] By ensuring that Sa1 is within the above range, the surface roughness of the main surface of the substrate on which the adhesive layer is not formed is relatively rough as a whole, which reduces the contact area with the release film and thereby suppresses unwinding defects.

[0050] Sa1 is preferably 0.55 μm or more, more preferably 0.60 μm or more, and even more preferably 0.65 μm or more. On the other hand, the upper limit of Sa1 is not limited as long as the above-mentioned gloss value is within the above-mentioned range, but is preferably 1.2 μm or less.

[0051] Sa1 is the surface roughness obtained by measuring a rectangular area of 4.91 mm x 4.90 mm.

[0052] Furthermore, in this embodiment, in addition to the above-mentioned Sa1, it is preferable to control the surface roughness in a small area obtained by dividing the area where the above-mentioned Sa1 is measured.

[0053] Specifically, a 4.91 mm × 4.90 mm square area on the main surface where the adhesive layer is not formed is defined as an area obtained by combining a 0.36 mm × 0.27 mm square area. Therefore, the 4.91 mm × 4.90 mm square area is a wide area, and the 0.36 mm × 0.27 mm square area is a narrow area.

[0054] 3, the 4.91 mm × 4.90 mm rectangular region 50 is obtained by combining 15 columns in the X-axis direction and 20 rows in the Y-axis direction of 0.36 mm × 0.27 mm rectangular regions 60, that is, 300 regions. Therefore, the wide region 50 is composed of 300 narrow regions 60.

[0055] In this embodiment, the arithmetic mean height is calculated for each 0.36 mm × 0.27 mm rectangular region 60. That is, the arithmetic mean height is measured for each narrow region 60 to obtain 300 arithmetic mean heights. Of the 300 arithmetic mean heights, the 20 smallest arithmetic mean height is selected. That is, of the 300 narrow regions 60 obtained by subdividing the wide region 50, 20 smooth narrow regions (with low surface roughness) are selected. The arithmetic mean heights of the selected 20 narrow regions are averaged to obtain Sa2. In this embodiment, Sa2 is 0.43 μm or less.

[0056] As described above, Sa1 is the surface roughness obtained by measuring the entire wide area 50, whereas Sa2 is the surface roughness of a locally smooth area in the wide area 50. Normally, unevenness on a surface is almost uniform, and when the narrow areas are the above-mentioned size, unevenness is almost uniform in each narrow area. As a result, there is not much difference in the surface roughness of each narrow area, and it is close to the surface roughness of the wide area, which is the area obtained by combining the narrow areas.

[0057] Therefore, when the surface irregularities are almost uniform, even if 20 narrow areas with small surface roughness are selected from the 300 narrow areas 60, the average surface roughness Sa2 will be close to the wide area surface roughness Sa1.

[0058] In contrast, in this embodiment, although Sa1 is greater than 0.50 μm, Sa2 is 0.43 μm or less. Therefore, the fact that Sa1 and Sa2 are both within the above ranges indicates that on the main surface on which the adhesive layer is not formed, there are large irregularities such that the surface roughness of the entire wide area 50 is within the above range, but there are also many areas with small surface roughness. In other words, on the main surface on which the adhesive layer is not formed, relatively large irregularities are sparsely distributed on a relatively smooth surface.

[0059] Therefore, the relatively large irregularities reduce the contact area with the release film, and the smooth areas suppress scattering or diffuse reflection of laser light, making the marking clearer (i.e., improving laser marking properties), and furthermore, it becomes easier to increase the gloss value. In other words, because the main surface on which the pressure-sensitive adhesive layer is not formed has a surface texture that is different from that of a surface on which the surface irregularities are almost uniformly present, it is possible to achieve both payout property and laser marking property, which are contradictory properties.

[0060] Sa2 is preferably 0.35 μm or less, more preferably 0.30 μm or less. On the other hand, the lower limit of Sa2 is not limited as long as the gloss value is within the above range, but is preferably 0.10 μm or more.

[0061] In this embodiment, the ratio of Sa1 to Sa2 (Sa1 / Sa2) is preferably 1.40 or more. When Sa1 / Sa2 is within the above range, it is possible to achieve both high levels of payout performance and laser marking performance.

[0062] Sa1 / Sa2 is more preferably 1.70 or more, even more preferably 2.0 or more, and particularly preferably 2.3 or more.

[0063] The surface texture of the main surface of the substrate on which the pressure-sensitive adhesive layer is not formed can be measured as follows. When the main surface on which the pressure-sensitive adhesive layer is not formed is represented as an XY plane using mutually perpendicular X-axis and Y-axis, the surface texture of the main surface on which the pressure-sensitive adhesive layer is not formed can be represented as a displacement in the Z-axis direction perpendicular to the XY plane. In other words, the surface roughness of the main surface on which the pressure-sensitive adhesive layer is not formed is represented as a three-dimensional (X, Y, Z) shape.

[0064] Therefore, the arithmetic mean height, which is a surface roughness parameter, is calculated from the measurement results of the displacement in the Z-axis direction in the measurement area. In this embodiment, it is preferable to use a non-contact white light interference microscope to measure the surface texture.

[0065] In a white light interference microscope, the optical path of light emitted from a white light source is split into two, one directed at a reference mirror and the other at the sample surface, and the light reflected from both is imaged on a camera. In the image obtained, the information on interference fringes generated by the optical path difference due to the unevenness of the sample surface is converted into height information, and the 3D shape of the sample surface can be obtained.

[0066] The measurement results of the surface texture of a measurement surface, obtained as 3D shape data, mainly include factors attributable to the shape of the measurement surface, factors attributable to the surface roughness of the measurement surface, and factors attributable to the waviness of the measurement surface. Therefore, the measurement results of the surface texture of a measurement surface are a contour curved surface obtained by combining these factors. These factors are distinguished by the length of their period (wavelength), with factors attributable to surface roughness having a short period (short wavelength), factors attributable to shape having a long period (long wavelength), and factors attributable to waviness having a period intermediate between these two.

[0067] From the obtained measurement results, factors due to shape and factors due to waviness are removed to obtain a surface roughness surface composed of factors due to surface roughness. Based on the obtained surface roughness surface, the arithmetic mean height is calculated in accordance with the method specified in ISO 25178. That is, the measurement can be performed using a method similar to the method specified in ISO 25178, but it may also be performed under conditions different from those specified in ISO 25178.

[0068] The operation of obtaining a surface roughness curve from the measurement results can be performed by known filtering, flattening, etc. For example, analysis software attached to a white light interference microscope or commercially available analysis software can be used.

[0069] When measuring the surface texture of the main surface, the magnification of the white light interference microscope is preferably 20 to 110 times, and more preferably 50 times.

[0070] The wide region 50 is obtained by combining 300 narrow regions 60, and as shown in FIG. 4, the narrow regions are combined with their peripheries overlapping. That is, when focusing on one of the narrow regions (60a) that make up the wide region 50, the periphery of the narrow region 60a overlaps with the peripheries of the narrow regions 60b to 60i that are adjacent to the narrow region 60a. By providing such overlapping regions OA, it is possible to ensure continuity of the surface roughness at the boundary portions of the adjacent narrow regions. If the narrow regions 60 are combined without providing overlapping regions OA, irregularities that do not exist in the actual surface texture may be included as noise.

[0071] (3.3 Substrate material) The material of the substrate is not particularly limited as long as it can support the workpiece via the adhesive layer during processing and is a material that easily transmits the laser light used for laser marking. Typically, the substrate is made of a film primarily made of a resin-based material (hereinafter referred to as "resin film"). The wavelength of the laser light used for laser marking is preferably 1064 nm, 532 nm, 355 nm, or 266 nm, with 532 nm being more preferred from the standpoint of marking clarity and versatility.

[0072] Specific examples of resin films include polyethylene films such as low-density polyethylene (LDPE) film, linear low-density polyethylene (LLDPE) film, and high-density polyethylene (HDPE) film; polyolefin films such as polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, and norbornene resin film; ethylene copolymer films such as ethylene-vinyl acetate copolymer film, ethylene-(meth)acrylic acid copolymer film, and ethylene-(meth)acrylic acid ester copolymer film; polyvinyl chloride films such as polyvinyl chloride copolymer film; polyester films such as polyethylene terephthalate film and polybutylene terephthalate film; polyurethane films; polyimide films; polystyrene films; polycarbonate films; and fluororesin films. Modified films such as crosslinked films and ionomer films are also used. The substrate may be a film made of one of these materials, or a laminate film combining two or more of these materials.

[0073] Among the above, polyethylene film, polypropylene film, ethylene-vinyl acetate copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polyvinyl chloride film, and polybutylene terephthalate film are preferred from the viewpoint of easily obtaining the effect of the payout property of the present invention and being easy to use in dicing processes, etc., and among these, polypropylene film, which has excellent heat resistance, is preferred.

[0074] (4. Adhesive Layer) The adhesive layer of the support sheet may be made of a non-energy ray curable adhesive or an energy ray curable adhesive, but is preferably made of a material that easily transmits the laser light used for laser marking.

[0075] The non-energy ray curable adhesive is preferably one having the desired adhesive strength and removability, and examples of adhesives that can be used include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives.

[0076] Among these, acrylic pressure-sensitive adhesives are preferred because they have high adhesion to the protective film-forming film and can effectively prevent the workpiece or processed product of the workpiece from falling off during a dicing process, etc. In addition, acrylic pressure-sensitive adhesives are preferred from the viewpoint of easily controlling the pick-up suitability of the processed product of the workpiece with the protective film.

[0077] The non-energy ray curable adhesive preferably contains a crosslinking agent such as an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent in order to crosslink the main component (for example, acrylic polymer).

[0078] On the other hand, the adhesive strength of energy ray-curable adhesives decreases when irradiated with energy rays, so when it is desired to separate the workpiece or a processed product of the workpiece from the support sheet, they can be easily separated by irradiating them with energy rays.

[0079] The energy ray-curable adhesive constituting the adhesive layer may be one whose main component is a polymer having energy ray curability, or one whose main component is a mixture of a polymer not having energy ray curability and an energy ray-curable monomer and / or oligomer.

[0080] Examples of energy ray-curable polymers include (meth)acrylic acid ester (co)polymers into which energy ray-curable groups have been introduced. Examples of energy ray-curable monomers and / or oligomers include esters of polyhydric alcohols and (meth)acrylic acid. The energy ray-curable adhesive may also contain additives such as photopolymerization initiators and crosslinking agents in addition to the energy ray-curable components.

[0081] The thickness of the pressure-sensitive adhesive layer is not particularly limited as long as it can function appropriately in each process in which the composite sheet for forming a protective film is used. Specifically, the thickness of the pressure-sensitive adhesive layer is preferably 1 to 50 μm, 2 to 30 μm, 2 to 20 μm, 3 to 10 μm, or 3 to 8 μm.

[0082] (5. Protective film forming film) The protective film-forming film of the composite sheet for forming a protective film is attached to a workpiece to form a protective film for protecting the workpiece or a processed product of the workpiece.

[0083] "Protecting" refers to making the protective film-forming film into a state in which it has sufficient properties to protect the workpiece or a processed product of the workpiece. Specifically, when the protective film-forming film is curable, "protecting" refers to making the uncured protective film-forming film into a cured product. In other words, the protective film-forming film that has been made into a protective film is a cured product of the protective film-forming film and is different from the protective film-forming film.

[0084] After the workpiece is superimposed on the curable protective film-forming film, the protective film-forming film is cured, whereby the protective film can be firmly adhered to the workpiece, and a durable protective film can be formed.

[0085] On the other hand, when the protective film-forming film does not contain a curable component and is used in an uncured state, the protective film-forming film becomes a protective film when it is attached to a workpiece. In other words, the protective film-forming film that has become a protective film is the same as the protective film-forming film.

[0086] When high protective performance is not required, the protective film-forming film does not need to be cured, and therefore the protective film-forming film is easy to use.

[0087] In this embodiment, the protective film-forming film is preferably curable. Therefore, the protective film is preferably a cured product. Examples of the cured product include a thermosetting product and an energy ray-cured product. In this embodiment, the protective film is more preferably a thermosetting product.

[0088] In addition, it is preferable that the protective film-forming film has adhesiveness at room temperature (23°C) or exhibits adhesiveness when heated. This allows the workpiece to be laminated to the protective film-forming film when it is placed on top of the film. Therefore, positioning can be reliably performed before the protective film-forming film is cured.

[0089] The protective film-forming film may be composed of one layer (single layer) or may be composed of two or more layers. When the protective film-forming film has multiple layers, these multiple layers may be the same or different from each other, and the combination of layers constituting these multiple layers is not particularly limited.

[0090] In this embodiment, the protective film-forming film is preferably one layer (single layer). A one-layer protective film-forming film can be easily produced because it can achieve high precision in thickness. Furthermore, if the protective film-forming film is composed of multiple layers, it is necessary to consider the adhesion between the layers and the stretchability of each layer, which may result in the risk of peeling from the adherend. If the protective film-forming film is one layer, the above risks can be reduced and design freedom is increased. Furthermore, the risk of peeling between layers due to differences in thermal stretchability between layers can be reduced in processes where temperature changes occur (during reflow processing or when using the device).

[0091] The thickness of the protective film-forming film is not particularly limited, but is preferably 100 μm or less, 70 μm or less, 45 μm or less, or 30 μm or less. The thickness of the protective film-forming film is preferably 5 μm or more, 10 μm or more, or 15 μm or more. When the thickness of the protective film-forming film is within the above range, the protective performance of the resulting protective film is improved.

[0092] The thickness of the protective film-forming film means the thickness of the entire protective film-forming film. For example, the thickness of a protective film-forming film composed of multiple layers means the total thickness of all layers constituting the protective film-forming film.

[0093] The following describes the protective film formed on the tip as the processed product of the workpiece. Specifically, the protective film formed by converting the protective film-forming film into a protective film using the protective film-equipped tip 70 shown in FIG.

[0094] As shown in Figure 5, in the chip 70 with a protective film, a protective film 40 is formed on the back side (upper side in Figure 5) of the chip 6a, and a convex electrode 6b is formed on the front side (lower side in Figure 5) of the chip 6a.

[0095] A circuit is formed on the surface of the chip 6a, and the convex electrodes 6b are formed so as to be electrically connected to the circuit. Examples of the convex electrodes 6b include bumps and pillar electrodes.

[0096] In this embodiment, the protective film-covered chip 70 is placed on the chip-mounting substrate so that the surface on which the convex electrodes 6b are formed faces the chip-mounting substrate. By a predetermined heating process (for example, a reflow process), the convex electrodes 6b and the substrate are electrically and mechanically bonded, and the protective film-covered chip 70 is mounted on the substrate.

[0097] (5.1 Composition for Protective Film-Forming Film) As long as the protective film has the above-mentioned physical properties, the composition of the protective film-forming film is not particularly limited. In this embodiment, the composition constituting the protective film-forming film (composition for protective film-forming film) is preferably a resin composition containing at least a polymer component (A), a curable component (B), and a filler (E). The polymer component is a component that can be considered to be formed by a polymerization reaction of a polymerizable compound. Furthermore, the curable component is a component that can undergo a curing (polymerization) reaction. In the present invention, the polymerization reaction also includes a polycondensation reaction.

[0098] In addition, a component contained in the polymer component may also be a curable component. In this embodiment, when the composition for a protective film-forming film contains a component that corresponds to both a polymer component and a curable component, the composition for a protective film-forming film is considered to contain both a polymer component and a curable component.

[0099] 5.1.1 Polymer Components The polymer component (A) provides the protective film-forming film with film-forming properties (film-forming properties) while imparting appropriate tack, ensuring uniform application of the protective film-forming film to the workpiece. The weight-average molecular weight of the polymer component is usually in the range of 50,000 to 2,000,000, preferably 100,000 to 1,500,000, and particularly preferably 200,000 to 1,000,000. Examples of such polymer components include acrylic resins, urethane resins, phenoxy resins, silicone resins, and saturated polyester resins, with acrylic resins being particularly preferred.

[0100] In this specification, unless otherwise specified, the "weight average molecular weight" is a polystyrene equivalent value measured by gel permeation chromatography (GPC). Measurements by such a method can be carried out, for example, using a high-speed GPC apparatus "HLC-8120GPC" manufactured by Tosoh Corporation, with a high-speed column "TSK guard column H" (Figure 1). XL -H", "TSK Gel GMH XL ", "TSK Gel G2000 H XL(All products of Tosoh Corporation) connected in this order are used, and the column temperature is 40°C, the liquid flow rate is 1.0 mL / min, and the detector is a differential refractometer.

[0101] Examples of acrylic resins include (meth)acrylic acid ester copolymers composed of structural units derived from (meth)acrylic acid ester monomers and (meth)acrylic acid derivatives. The (meth)acrylic acid ester monomers are preferably (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 18 carbon atoms, specifically methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, etc. Examples of (meth)acrylic acid derivatives include (meth)acrylic acid, glycidyl (meth)acrylate, hydroxyethyl (meth)acrylate, etc.

[0102] In this embodiment, it is preferable to introduce a glycidyl group into the acrylic resin using glycidyl methacrylate or the like. The compatibility of the acrylic resin into which the glycidyl group has been introduced with the epoxy resin as the thermosetting component described below is improved, and a protective film-forming film with stable performance tends to be obtained. Furthermore, in this embodiment, it is preferable to introduce a hydroxyl group into the acrylic resin using hydroxyethyl acrylate or the like in order to control the adhesiveness to the workpiece and the adhesive properties.

[0103] The glass transition temperature of the acrylic resin is preferably −70° C. to 40° C., −35° C. to 35° C., −20° C. to 30° C., −10° C. to 25° C., or −5° C. to 20° C. By setting the glass transition temperature of the acrylic resin within the above range, the tack of the protective film-forming film is appropriately increased, and the adhesive strength of the protective film-forming film to the workpiece is improved, thereby appropriately improving the adhesive strength of the protective film to the workpiece.

[0104] When an acrylic resin has m types of structural units (m is an integer of 2 or more), the glass transition temperature of the acrylic resin can be calculated as follows: That is, when m types of monomers that derive the structural units in the acrylic resin are each sequentially assigned a unique number from 1 to m and named "monomer m," the glass transition temperature (Tg) of the acrylic resin can be calculated using the Fox formula shown below.

number

number

[0105] For Tgk, values listed in the Polymer Data Handbook, Adhesive Handbook, or Polymer Handbook can be used. For example, the Tgk of a homopolymer of methyl acrylate is 10°C, that of a homopolymer of n-butyl acrylate is -54°C, that of a homopolymer of methyl methacrylate is 105°C, that of a homopolymer of 2-hydroxyethyl acrylate is -15°C, that of a homopolymer of glycidyl methacrylate is 41°C, and that of 2-ethylhexyl acrylate is -70°C.

[0106] When the total weight of the composition for the protective film-forming film is taken as 100 parts by mass, the content of the polymer component is preferably 5 to 80 parts by mass, 8 to 70 parts by mass, 10 to 60 parts by mass, 12 to 55 parts by mass, 14 to 50 parts by mass, or 15 to 45 parts by mass. By setting the content of the polymer component within the above range, it becomes easy to control the tackiness of the protective film-forming film.

[0107] (5.1.2 Thermosetting components) The curable component (B) cures the protective film-forming film to form a hard protective film. As the curable component, a thermosetting component, an energy ray-curable component, or a mixture thereof can be used. When cured by irradiation with energy rays, the protective film-forming film according to this embodiment contains a filler and a colorant, etc., which will be described later, and therefore the light transmittance is reduced. Therefore, for example, when the thickness of the protective film-forming film is increased, the energy ray curing is likely to be insufficient.

[0108] On the other hand, a thermosetting protective film-forming film can be sufficiently cured by heating even if it is thick, so that a protective film with high protective performance can be formed. Furthermore, by using a conventional heating means such as a heating oven, a large number of protective film-forming films can be heated and thermally cured all at once.

[0109] Therefore, in this embodiment, it is desirable that the curable component is thermosetting, that is, the protective film-forming film according to this embodiment is preferably thermosetting.

[0110] Whether or not a protective film-forming film is thermosetting can be determined as follows. First, a protective film-forming film at room temperature (23°C) is heated to a temperature above room temperature, and then cooled to room temperature to obtain a protective film-forming film after heating and cooling. Next, when the hardness of the protective film-forming film after heating and cooling is compared with the hardness of the protective film-forming film before heating at the same temperature, if the protective film-forming film after heating and cooling is harder, the protective film-forming film is determined to be thermosetting.

[0111] Preferred examples of thermosetting components include epoxy resins, thermosetting polyimide resins, unsaturated polyester resins, and mixtures thereof. Thermosetting polyimide resins are a general term for low-molecular-weight, low-viscosity monomers or precursor polymers that form polyimide resins by thermal curing. Non-limiting examples of thermosetting polyimide resins are described in, for example, the Sen'i Gakkaishi Journal, "Sen'i to Kogyo," Vol. 50, No. 3 (1994), pp. 106-118.

[0112] Epoxy resins as thermosetting components have the property of undergoing three-dimensional network formation upon heating, forming a strong coating. Various known epoxy resins are used as such epoxy resins. In this embodiment, the molecular weight (formula weight) of the epoxy resin is preferably 300 or more and less than 50,000, 300 or more and less than 10,000, 300 or more and less than 5,000, or 300 or more and less than 3,000. The epoxy equivalent of the epoxy resin is preferably 50 to 5,000 g / eq, more preferably 100 to 2,000 g / eq, and even more preferably 150 to 1,000 g / eq.

[0113] Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidyl or alkylglycidyl epoxy resins in which the active hydrogen bonded to the nitrogen atom is substituted with a glycidyl group, such as aniline isocyanurate; and so-called alicyclic epoxides in which epoxy groups are introduced by, for example, oxidizing carbon-carbon double bonds within the molecule, such as vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane. Other epoxy resins that can be used include those having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, and the like.

[0114] When a thermosetting component is used as the curing component (B), it is preferable to use a curing agent (C) as an auxiliary. Heat-activated latent epoxy resin curing agents are preferred as curing agents for epoxy resins. A "heat-activated latent epoxy resin curing agent" is a type of curing agent that is difficult to react with epoxy resins at room temperature (23°C) but becomes activated and reacts with epoxy resins when heated above a certain temperature. Activation methods for heat-activated latent epoxy resin curing agents include generating active species (anions and cations) through a chemical reaction caused by heating; stably dispersing the curing agent in the epoxy resin at room temperature and becoming compatible and dissolved with the epoxy resin at high temperatures to initiate the curing reaction; using a molecular sieve-encapsulated curing agent that dissolves at high temperatures to initiate the curing reaction; and using microcapsules.

[0115] Of the methods exemplified above, a method in which the compound is stably dispersed in the epoxy resin at around room temperature, becomes compatible and dissolved with the epoxy resin at high temperatures, and initiates a curing reaction is preferred.

[0116] Specific examples of heat-activated latent epoxy resin curing agents include various onium salts, dibasic acid dihydrazide compounds, dicyandiamide, amine adduct curing agents, and high-melting-point active hydrogen compounds such as imidazole compounds. These heat-activated latent epoxy resin curing agents can be used alone or in combination of two or more. In this embodiment, dicyandiamide is particularly preferred.

[0117] Phenol resins are also preferred as curing agents for epoxy resins. Examples of phenolic resins that can be used include, but are not limited to, condensates of phenols such as alkylphenols, polyphenols, and naphthol with aldehydes. Specific examples include phenol novolac resins, o-cresol novolac resins, p-cresol novolac resins, t-butylphenol novolac resins, dicyclopentadiene cresol resins, polyparavinylphenol resins, bisphenol A novolac resins, and modified versions of these resins.

[0118] The phenolic hydroxyl groups contained in these phenolic resins can easily undergo addition reaction with the epoxy groups of the epoxy resins by heating to form a cured product with high impact resistance.

[0119] The content of the curing agent (C) is preferably 0.01 to 30 parts by mass, 0.1 to 20 parts by mass, 0.2 to 15 parts by mass, or 0.3 to 10 parts by mass relative to 100 parts by mass of the epoxy resin. By setting the content of the curing agent (C) within the above range, the network structure of the protective film becomes dense, making it easier to obtain the protective film's ability to protect the workpiece.

[0120] When dicyandiamide is used as the curing agent (C), it is preferable to use a curing accelerator (D) in combination. Examples of the curing accelerator include imidazoles (imidazoles in which one or more hydrogen atoms are substituted with groups other than hydrogen atoms), such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Among these, 2-phenyl-4,5-dihydroxymethylimidazole is particularly preferred.

[0121] The content of the curing accelerator is preferably 0.01 to 30 parts by mass, 0.1 to 20 parts by mass, 0.2 to 15 parts by mass, or 0.3 to 10 parts by mass relative to 100 parts by mass of the epoxy resin. By setting the content of the curing accelerator (D) within the above range, the network structure of the protective film becomes dense, making it easier for the protective film to achieve the performance of protecting the workpiece.

[0122] When the total weight of the composition for a protective film-forming film is 100 parts by mass, the total content of the thermosetting component and the curing agent is preferably 3 to 80 parts by mass, 5 to 60 parts by mass, 7 to 50 parts by mass, 9 to 40 parts by mass, or 10 to 30 parts by mass. When the thermosetting component and the curing agent are blended in such a ratio, the composition exhibits appropriate tack before curing, allowing stable application. Furthermore, after curing, the composition is likely to provide the ability to protect the workpiece as a protective film.

[0123] (5.1.3 Energy ray curable component) When the curable component (B) is an energy ray-curable component, the energy ray-curable component is preferably uncured and has adhesive properties, and more preferably uncured and has adhesive properties.

[0124] The energy ray curable component is a component that is cured by irradiation with energy rays, and is also a component that imparts film-forming properties, flexibility, and the like to the protective film-forming film.

[0125] The energy ray-curable component is preferably, for example, a compound having an energy ray-curable group, and examples of such compounds include known compounds.

[0126] (5.1.4 Filler) By including the filler (E) in the protective film-forming film, the protective film obtained by converting the protective film-forming film into a protective film can easily have its thermal expansion coefficient adjusted, and by making this thermal expansion coefficient closer to the thermal expansion coefficient of the workpiece, the adhesive reliability of the protective film-equipped chip obtained using the protective film-forming film is further improved. Furthermore, by including the filler (E) in the protective film-forming film, a hard protective film can be obtained, and the moisture absorption rate of the protective film can be reduced, further improving the adhesive reliability of the protective film-equipped chip.

[0127] The filler (E) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler from the viewpoint of shape stability at high temperatures.

[0128] Preferred inorganic fillers include, for example, powders of silica, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, boron nitride, etc.; beads of these inorganic fillers that have been spherically formed; surface-modified products of these inorganic fillers; single-crystal fibers of these inorganic fillers; glass fibers, etc. Among these, silica and surface-modified silica are preferred. The surface-modified silica is preferably surface-modified with a coupling agent, more preferably surface-modified with a silane coupling agent.

[0129] The average particle size of the filler is preferably 0.02 to 10 μm, 0.05 to 5 μm, or 0.10 to 3 μm.

[0130] By setting the average particle size of the filler within the above range, the composition for a protective film-forming film can be easily handled, and as a result, the quality of the composition for a protective film-forming film and the protective film-forming film can be easily stabilized.

[0131] In this specification, unless otherwise specified, the term "average particle size" refers to the particle size (D50) at an integrated value of 50% in a particle size distribution curve determined by a laser diffraction scattering method.

[0132] When the total weight of the composition for a protective film-forming film is taken as 100 parts by mass, the content of the filler is preferably 15 to 80 parts by mass, 30 to 75 parts by mass, 40 to 70 parts by mass, or 45 to 65 parts by mass.

[0133] By setting the lower limit of the filler content to the above value, the adhesive reliability of the protective film-coated chip obtained using the protective film-forming film is further improved. Also, by setting the upper limit of the filler content to the above value, the adhesive strength of the protective film-forming film to the workpiece is improved, and the adhesive strength of the protective film to the workpiece is appropriately improved.

[0134] 5.1.5 Coupling Agents The protective film-forming film preferably contains a coupling agent (F). By containing the coupling agent, after the protective film-forming film is cured, the adhesion between the protective film and the workpiece can be improved without impairing the heat resistance of the protective film, and the water resistance (moist heat resistance) can be improved. As the coupling agent, a silane coupling agent is preferred from the viewpoint of its versatility and cost benefits.

[0135] Examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These may be used alone or in combination of two or more.

[0136] When the total weight of the composition for a protective film-forming film is taken as 100 parts by mass, the content of the coupling agent is preferably 0.01 to 20 parts by mass, 0.1 to 10 parts by mass, 0.2 to 5 parts by mass, or 0.3 to 3 parts by mass.

[0137] 5.1.6 Colorants The protective film-forming film preferably contains a colorant (G). This conceals the back surface of the workpiece, such as a chip, thereby blocking various electromagnetic waves generated within electronic devices and reducing malfunction of the workpiece, such as a chip. In addition, the recognizability of laser marking is further improved.

[0138] As the colorant (G), for example, known colorants such as organic pigments, organic dyes, inorganic pigments, etc. In this embodiment, inorganic pigments are preferred.

[0139] Examples of inorganic pigments include carbon black, cobalt-based pigments, iron-based pigments, chromium-based pigments, titanium-based pigments, vanadium-based pigments, zirconium-based pigments, molybdenum-based pigments, ruthenium-based pigments, platinum-based pigments, ITO (indium tin oxide)-based pigments, and ATO (antimony tin oxide)-based pigments. Among these, carbon black is particularly preferred. Carbon black can block electromagnetic waves over a wide wavelength range.

[0140] The amount of colorant (especially carbon black) in the protective film-forming film varies depending on the thickness of the protective film-forming film, but for example, when the thickness of the protective film-forming film is 20 μm, the content of the colorant is preferably 0.01 to 10 parts by mass, 0.03 to 7 parts by mass, or 0.05 to 4 parts by mass when the total weight of the composition for the protective film-forming film is 100 parts by mass.

[0141] The average particle size of the colorant (particularly carbon black) is preferably 1 to 500 nm, 3 to 100 nm, or 5 to 50 nm. When the average particle size of the colorant is within the above range, it is easy to control the light transmittance within a desired range.

[0142] (5.1.7 Other additives) The composition for the protective film-forming film may contain other additives, such as a photopolymerization initiator, a crosslinking agent, a plasticizer, an antistatic agent, an antioxidant, a gettering agent, a tackifier, a release agent, etc., within the range that does not impair the effects of the present invention.

[0143] (6. Adhesive layer for jig) The adhesive constituting the jig adhesive layer is preferably one having the desired adhesive strength and removability, and examples thereof include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives. Among these, acrylic adhesives are preferred because they have high adhesion to jigs such as ring frames and can effectively prevent the composite sheet for forming a protective film from peeling from the ring frame during dicing processes, etc. A substrate serving as a core material may be interposed in the thickness direction of the jig adhesive layer.

[0144] The thickness of the pressure-sensitive adhesive layer for jigs is preferably 5 to 200 μm, particularly preferably 10 to 100 μm, from the viewpoint of adhesiveness to jigs such as ring frames.

[0145] (7. Release film) The release film is preferably disposed on the surface of the pressure-sensitive adhesive layer of the support sheet and on the surface of the protective film-forming film of the composite sheet for forming a protective film. The release film may be composed of one layer (single layer) or two or more layers of substrate, and the surface of the substrate may be subjected to a release treatment in order to control the releasability. That is, the surface of the substrate may be modified, or a material (release agent layer) not derived from the substrate may be formed on the surface of the substrate.

[0146] The substrate is not particularly limited as long as it is a material that can support the protective film-forming film until it is attached to the workpiece, and is usually composed of a film mainly made of a resin-based material. In this embodiment, a polyethylene terephthalate film is preferred from the viewpoints of environmental safety, cost, etc. The substrate may contain various additives such as colorants, flame retardants, plasticizers, antistatic agents, lubricants, and fillers.

[0147] The release agent layer is obtained by applying a coating agent containing a composition for a release agent layer to one surface of a substrate, and then drying and curing the coating. The composition for a release agent layer is not particularly limited as long as it is a material that can impart releasability from the protective film-forming film to the substrate. In this embodiment, the composition for a release agent layer is preferably, for example, an alkyd-based release agent, a silicone-based release agent, a fluorine-based release agent, an unsaturated polyester-based release agent, a polyolefin-based release agent, or a wax-based release agent, and among these, a silicone-based release agent is preferred.

[0148] The thickness of the release film is not particularly limited, but is preferably 15 to 100 μm, more preferably 25 to 80 μm, and even more preferably 35 to 60 μm.

[0149] (8. Method for producing a composite sheet for forming a support sheet and a protective film) The support sheet is manufactured, for example, as follows. First, a substrate for the support sheet is prepared. The substrate may be obtained by melt-kneading a raw material composition and extruding the sheet-like substrate using an extruder, and then contacting the substrate in a soft state with a roll that has been treated with a predetermined unevenness, such as a grained finish, to form the surface texture described above. Alternatively, the raw material substrate may be passed between a roll that has been treated with a predetermined unevenness, such as a grained finish, and a roll that has not been treated with an unevenness, and the unevenness formed on the roll is transferred to the substrate to obtain a substrate with the surface texture described above.

[0150] Examples of the predetermined unevenness treatment include grinding with abrasive stone, wet blasting such as liquid honing, and dry blasting such as sand blasting. Grinding with abrasive stone is a treatment for grinding the surface of the roll, and is usually a treatment for smoothing the surface of the roll. Wet blasting and dry blasting are treatments for changing the surface condition of the roll by spraying an abrasive onto the surface of the roll, and are usually treatments for forming unevenness on the surface of the roll. The size of the unevenness can be controlled by changing the material, particle size, etc. of the abrasive.

[0151] Therefore, by combining the treatment for smoothing the surface with the treatment for forming irregularities, it is possible to obtain a roll having a surface treated to have predetermined irregularities.

[0152] Next, a pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer, or a composition obtained by diluting the pressure-sensitive adhesive composition with a solvent (these two compositions are referred to as "coating agents"). The resulting coating agent is applied to the release surface of a first release film using a coating machine such as a roll coater, knife coater, roll knife coater, air knife coater, die coater, bar coater, gravure coater, or curtain coater, and dried as necessary to form a pressure-sensitive adhesive layer on the first release film. Next, the exposed surface of the pressure-sensitive adhesive layer is bonded to the main surface of the substrate prepared above that does not have the above-mentioned surface texture, to produce a support sheet having a first release film on the surface of the pressure-sensitive adhesive layer.

[0153] Here, when the pressure-sensitive adhesive layer is made of an energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer may be cured by irradiating it with energy rays at this stage, or the pressure-sensitive adhesive layer may be cured after laminating it with the protective film-forming film. Furthermore, when the pressure-sensitive adhesive layer is cured after laminating it with the protective film-forming film, the pressure-sensitive adhesive layer may be cured before the dicing step, or the pressure-sensitive adhesive layer may be cured after the dicing step.

[0154] As the energy beam, ultraviolet rays, electron beams, etc. are usually used. The irradiation dose of the energy beam varies depending on the type of energy beam. For example, in the case of ultraviolet rays, the light dose is 50 to 1000 mJ / cm. 2 is preferred, and particularly 100 to 500 mJ / cm 2 In the case of electron beams, the intensity is preferably about 10 to 1000 krad.

[0155] The composite sheet for forming a protective film can be produced, for example, by separately producing the support sheet prepared above and a laminate including the protective film-forming film, and then using the support sheet and the laminate to laminate the protective film-forming film and the support sheet.

[0156] First, the above-mentioned composition for a protective film-forming film, or a composition obtained by diluting the composition for a protective film-forming film with a solvent (these two compositions are referred to as "coating agents"), is prepared. Subsequently, the coating agent is applied to the release surface of the second release film, and dried as necessary to form a protective film-forming film on the second release film. Next, the release surface of the third release film is bonded to the exposed surface of the protective film-forming film to obtain a laminate.

[0157] After the support sheet and laminate are obtained as described above, the first release film of the support sheet is peeled off, and the third release film of the laminate is peeled off, and the exposed adhesive layer of the support sheet is bonded to the exposed protective film-forming film. If necessary, after peeling off the second release film, a jig adhesive layer formed on a fourth release film is bonded to the peripheral portion of the exposed protective film-forming film or adhesive layer. In this way, the composite sheet for forming a protective film shown in FIG. 2 is obtained.

[0158] The obtained support sheet and composite sheet for forming a protective film are cut on both sides in the width direction to fit the size of the work to be attached, and the width size is adjusted, and then the sheet is wound up by a winding device while applying a predetermined tension to it, to form a sheet roll.

[0159] (9. Device Manufacturing Method) As an example of a method for manufacturing a device using the support sheet and protective film-forming composite sheet of this embodiment, a method for manufacturing a chip with a protective film obtained by processing a wafer to which a protective film-forming film is attached will be described.

[0160] The method for manufacturing the device according to this embodiment includes at least the following steps 1 to 5. Step 1: Unwinding and unrolling the rolled composite sheet for forming the protective film Step 2: A step of attaching the protective film forming film of the unwound composite sheet for protective film formation to the backside of the wafer. Step 3: The process of making the attached protective film into a protective film Step 4: Laser marking the protective film or protective film-forming film Step 5: A step of dividing the wafer having the protective film or protective film-forming film on the back surface into individual chips to obtain a plurality of chips with the protective film or protective film-forming film.

[0161] As is clear from the above, step 3 may be performed before or after step 5.

[0162] The manufacturing method of the device, which includes the above steps 1 to 5, will be described with reference to FIG.

[0163] First, the composite sheet for forming a protective film wound in a roll is unwound to unwind the composite sheet for forming a protective film (Step 1). At this time, since the surface properties of the main surface of the base material of the support sheet on which the adhesive layer is not formed are controlled as described above, blocking does not occur between the base material and the release film formed on the protective film-forming film. As a result, poor unwinding of the composite sheet for forming a protective film can be suppressed.

[0164] Next, as shown in FIG. 6, the protective film-forming film 4 of the unwound composite sheet 10 for forming a protective film is attached to the back surface of the wafer 6 (step 2). At this time, the outer periphery of the protective film-forming film 4 may be fixed by a ring frame 7. In this embodiment, as shown in FIG. 6, a jig adhesive layer 5 is provided on the outer periphery of the protective film-forming film 4, so the jig adhesive layer 5 is attached to the ring frame 7. The wafer 6 is attached to the surface of the protective film-forming film 4 opposite to the surface attached to the adhesive layer 3. When attaching the protective film-forming film 4 to the wafer 6, the protective film-forming film 4 may be heated, if desired, to exhibit adhesiveness.

[0165] Thereafter, the attached protective film-forming film 4 is made into a protective film to form a protective film (step 3), thereby obtaining a wafer 6 with a protective film. When the protective film-forming film 4 is thermosetting, the protective film-forming film 4 can be heated at a predetermined temperature for an appropriate time. When the protective film-forming film 4 is energy ray-curable, energy rays can be incident on the film from the support sheet 1.

[0166] The protective film-forming film 4 may be cured after the dicing step, or the chip with the protective film-forming film may be picked up from the adhesive sheet and then the protective film-forming film may be cured.

[0167] Next, the protective film is laser marked (Step 4). Step 4 is preferably performed after Step 3, and in this embodiment, Step 4 is more preferably performed before Step 5.

[0168] In the laser marking, marking may be performed by scraping off the surface of the protective film-forming film or protective film by laser irradiation, or by increasing the volume of the protective film-forming film or protective film by laser irradiation to form a convex portion. Laser marking may be performed using a known laser marking device.

[0169] Since the gloss value and surface properties of the main surface of the support sheet substrate on which the adhesive layer is not formed are controlled as described above, clear marking can be made and the marking can also be clearly recognized when observed.

[0170] Next, the protective film-coated wafer 6 is diced by a known method to obtain chips (protective film-coated chips 70) having the protective film 40 shown in Fig. 5 (step 5). That is, the support sheet of the composite sheet for forming a protective film can function as a dicing sheet.

[0171] (10. Variations) In the above embodiment, a composite sheet for forming a protective film in which a support sheet and a protective film-forming film are integrated has been described, but the support sheet and the protective film-forming film do not have to be integrated. That is, a kit composed of the above support sheet and a protective film-forming film to be attached to the surface of the adhesive layer of the support sheet is also included in the present invention. This kit can be used by first attaching the protective film-forming film to a workpiece, and then attaching the adhesive layer of the support sheet and the protective film-forming film.

[0172] The composite sheet for forming a protective film may have a configuration shown in Fig. 7. The composite sheet for forming a protective film 11 shown in Fig. 7 is configured to include a support sheet 1 formed by laminating an adhesive layer 3 on one surface of a substrate 2, and a protective film-forming film 4 laminated on the adhesive layer 3 side of the support sheet 1. The protective film-forming film 4 is formed to be approximately the same size as the workpiece or slightly larger than the workpiece in a plan view, and smaller than the support sheet 1. The adhesive layer 3 in the portion not laminated with the protective film-forming film 4 can be attached to a jig such as a ring frame.

[0173] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and may be modified in various ways within the scope of the present invention. [Example]

[0174] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0175] Example 1 (Preparation of support sheet) First, the substrate constituting the support sheet was prepared as follows.

[0176] As a material for forming the substrate, a polypropylene film (tensile modulus of elasticity: 320 MPa in MD / 290 MPa in CD, melting point: 156°C) was melt-kneaded in a kneader to obtain a raw material for extrusion.

[0177] The obtained extrusion raw material was extrusion molded at 220°C using a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Laboplastomill (registered trademark)"), and the sheet immediately after molding was cooled with a metal roll (40°C) that had been embossed (grinding with a grinding wheel, wet blasting (liquid honing) treatment, dry blasting (sandblasting) treatment) to obtain a substrate with a thickness of 80 μm, with the surface roughness of the surface that came into contact with the metal roll adjusted.

[0178] Next, the adhesive layer that constitutes the support sheet was prepared as follows.

[0179] A coating agent containing a pressure-sensitive adhesive layer composition was prepared by adding 15 parts by mass of a trifunctional xylylene diisocyanate crosslinking agent (manufactured by Mitsui Takeda Chemicals Inc., trade name "Takenate 110N") to 100 parts by mass (solid content equivalent) of an acrylic copolymer (weight average molecular weight: 800,000) obtained by copolymerizing 80 parts by mass of 2-ethylhexyl acrylate (2EHA) and 20 parts by mass of 2-hydroxyethyl acrylate (HEA), and diluting with methyl ethyl ketone to a solid content concentration of 25% by mass.

[0180] The above-mentioned adhesive layer composition coating agent was applied to the release-treated surface of a release film (manufactured by Lintec Corporation, product name "SP-PET381031", a polyethylene terephthalate (PET) film with a silicone release treatment, thickness: 38 μm) and dried to produce a release film with an adhesive layer having a thickness of 5 μm.

[0181] The surface of the adhesive layer of the release film with the adhesive layer was bonded to the surface of the substrate whose surface roughness was not adjusted (the surface not in contact with the metal roll) to prepare a support sheet. This support sheet was long and was wound up into a sheet roll.

[0182] (1) Preparation of a first laminate including a protective film-forming film The following components (a) to (g) were mixed and diluted with methyl ethyl ketone to a solid content concentration of 50 mass %, to prepare a coating agent for a protective film-forming film. (a) Binder polymer: 150 parts by mass (solids equivalent, the same applies hereinafter) of (meth)acrylic acid ester copolymer (an acrylic copolymer obtained by copolymerizing 10 parts by mass of n-butyl acrylate, 70 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate, weight average molecular weight: 800,000, glass transition temperature: -1°C) (b-1) Thermosetting component: 60 parts by mass of bisphenol A epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER828", epoxy equivalent 184 to 194 g / eq) (b-2) Thermosetting component: 10 parts by mass of bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "jER1055", epoxy equivalent 800 to 900 g / eq) (b-3) Thermosetting component: 30 parts by mass of dicyclopentadiene-type epoxy resin (manufactured by Dainippon Ink and Chemicals, Inc., product name "Epiclon HP-7200HH", epoxy equivalent 255 to 260 g / eq) (c) Heat-activated latent epoxy resin curing agent: dicyandiamide (ADEKA Corporation: ADEKA Hardner EH3636AS, active hydrogen content 21 g / eq) 2 parts by mass (d) Curing accelerator: 2 parts by mass of 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemicals Corporation, product name "Curezol 2PHZ") (e) Filler: Silica filler (manufactured by Admatechs Co., Ltd., product name "SC2050MA", average particle size: 0.5 μm) 320 parts by mass (f) Colorant: Carbon black (manufactured by Mitsubishi Chemical Corporation, product name "#MA650", average particle size: 28 nm) 1.2 parts by mass (g) Silane coupling agent: (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM-403") 2 parts by mass

[0183] A first release film (manufactured by Lintec Corporation, product name "SP-PET381031") was prepared, which consisted of a 38 μm-thick polyethylene terephthalate (PET) film with a silicone-based release agent layer formed on one side thereof, and a second release film (manufactured by Lintec Corporation, product name "SP-PET381130") was prepared, which consisted of a 38 μm-thick PET film with a silicone-based release agent layer formed on one side thereof.

[0184] First, the coating agent for the protective film-forming film was applied to the release surface of the first release film using a knife coater and dried to form a protective film-forming film with a thickness of 25 μm. Then, the release surface of the second release film was placed on the protective film-forming film and the two were bonded together to obtain a first laminate consisting of the first release film, the protective film-forming film (thickness: 25 μm), and the second release film. This laminate was long and was wound up to form a sheet roll.

[0185] (2) Preparation of a second laminate including a pressure-sensitive adhesive layer for a jig The following components (j) and (k) were mixed and diluted with toluene to a solids concentration of 15 mass % to prepare a coating agent for a pressure-sensitive adhesive layer for a jig. (j) Adhesive base: 100 parts by mass of (meth)acrylic acid ester copolymer (a copolymer obtained by copolymerizing 69.5 parts by mass of butyl acrylate, 30 parts by mass of methyl acrylate, and 0.5 parts by mass of 2-hydroxyethyl acrylate, weight average molecular weight: 500,000) (k) Crosslinking agent: 5 parts by mass of tolylene diisocyanate crosslinking agent (manufactured by Toyochem Co., Ltd., product name "BHS8515")

[0186] First and second release films (manufactured by Lintec Corporation, product name "SP-PET381031") were prepared, each consisting of a 38 μm thick PET film with a silicone-based release agent layer formed on one side, and a polyvinyl chloride film (manufactured by Okamoto Corporation, thickness: 50 μm) was prepared as a core material.

[0187] First, the adhesive layer coating agent was applied to the release surface of the first release film using a knife coater and dried to form a 5 μm thick first adhesive layer. Then, the core material was attached to the first adhesive layer to obtain a laminate A consisting of the core material, the first adhesive layer, and the first release film. This laminate A was long and was wound up into a sheet roll.

[0188] Next, the adhesive layer coating agent was applied to the release surface of the second release film using a knife coater and dried to form a 5 μm thick second adhesive layer. The exposed surface of the core material in the laminate A was then attached to the second adhesive layer to obtain a second laminate consisting of the first release film / first adhesive layer / core material / second adhesive layer / second release film. This laminate was long and was wound up into a sheet roll.

[0189] (3) Preparation of the third laminate The second release film was peeled off from the first laminate obtained in (1) above to expose the protective film-forming film. Meanwhile, the release film was peeled off from the support sheet obtained above to expose the pressure-sensitive adhesive layer. The first laminate and the support sheet were attached together so that the protective film-forming film was in contact with the pressure-sensitive adhesive layer, thereby obtaining a third laminate in which the support sheet consisting of the substrate and the pressure-sensitive adhesive layer, the protective film-forming film, and the first release film were laminated.

[0190] (4) Preparation of composite sheet for forming protective film The second release film was peeled off from the second laminate obtained in (2) above, leaving the first release film, and the inner peripheral edge of the pressure-sensitive adhesive layer for the jig was half-cut to remove the inner circular portion, so that the diameter of the inner peripheral edge of the pressure-sensitive adhesive layer for the jig was 220 mm.

[0191] The first release film was peeled off from the third laminate obtained in (3) above, and the exposed protective film-forming film was superimposed on the exposed jig pressure-sensitive adhesive layer in the second laminate and pressure-bonded. Then, leaving the first release film in the second laminate, the outer periphery of the composite sheet for forming a protective film was half-cut to remove the outer portion. At this time, the diameter of the outer periphery of the composite sheet for forming a protective film was 270 mm.

[0192] In this way, a composite sheet for forming a protective film was obtained, which consisted of a support sheet having a pressure-sensitive adhesive layer (thickness: 5 μm) laminated on a substrate, a protective film-forming film laminated on the pressure-sensitive adhesive layer side of the support sheet, a circular pressure-sensitive adhesive layer for a jig laminated on the peripheral portion of the protective film-forming film on the side opposite the support sheet, and a release film laminated on the pressure-sensitive adhesive layer for a jig on the side opposite the protective film-forming film. This composite sheet for forming a protective film was long and was wound up into a sheet roll.

[0193] (Examples 2 to 4 and Comparative Examples 1 to 3) A composite sheet for forming a protective film was produced by the same method as in Example 1, except that the metal roll used to produce the substrate in Example 1 was changed to a metal roll with a predetermined grain shape by combining grinding wheel grinding, wet blasting, and dry blasting to change the state of existence of relatively large irregularities and a smooth surface, thereby changing the surface roughness of the surface in contact with the metal roll.

[0194] The support sheets or composite sheets for forming a protective film obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were used to carry out the following measurements and evaluations.

[0195] (Glossiness of exposed surface of substrate) The release film was peeled off from the support sheet of each example and comparative example and attached to a colorless, transparent soda-lime glass to prepare a measurement sample. A gloss meter (Nippon Denshoku Corporation's gloss meter "VG 2000") was used to measure the 60° specular gloss of the surface (exposed surface) of the substrate on which the adhesive layer was not formed, in accordance with JIS Z 8741, by irradiating the measurement sample from the side on which the adhesive layer was not formed. The measured value was used as the gloss value of the substrate surface. The results are shown in Table 1.

[0196] (Surface roughness Sa1 and Sa2 of the exposed surface of the substrate) The exposed surface of the substrate of the support sheet of each example and comparative example was observed using a scanning white light interference microscope VS-1550 manufactured by Hitachi High-Tech Science Corporation, and Sa1 and Sa2 were calculated as follows.

[0197] The observation magnification was 50x, and the observation was performed in multi-field mode. An area of 0.36 mm in the X-axis direction and 0.27 mm in the Y-axis direction was set in the observation field, and 15 columns in the X-axis direction and 20 rows in the Y-axis direction were observed, for a total of 300 cells.

[0198] The images of 300 cells were combined to form a single image measuring 4.91 mm x 4.90 mm. Sa was measured for the entire combined image, and this was designated as Sa1. The results are shown in Table 1.

[0199] Next, the Sa of each of the 300 cells was measured without image synthesis, yielding 300 Sa data points. Of the 300 Sa data points, the 20 smallest Sa data points were extracted. The average of the 20 extracted Sa data points was designated as Sa2. The results are shown in Table 1.

[0200] (Laser marking recognition) The release film was removed from the composite sheet for forming a protective film of each example and comparative example, and the composite sheet for forming a protective film and a ring frame were attached to a silicon wafer with a thickness of 350 μm and an outer diameter of 8 inches using an attachment device ("RAD-2700F / 12" manufactured by Lintec) at a temperature of 70°C. The protective film-forming film was then heat-cured at 130°C for 2 hours to form a protective film. Next, a laser was irradiated onto the protective film through the support sheet using a printing device (CSM300M manufactured by EO, wavelength 532 nm) to mark the protective film with the following two patterns (Pattern 1 and Pattern 2). Pattern 1: Character size 0.5mm x 0.5mm, character spacing 0.05mm, 20 characters Pattern 2: Character size 0.15mm x 0.25mm, character spacing: 0.05mm, number of characters: 20

[0201] The characters formed on the protective film by the above laser marking were observed both through the support sheet and without the support sheet (after removing the support sheet) and evaluated according to the following criteria. The results are shown in Table 1. A: I was able to read all the characters in patterns 1 and 2 without any problems. B: There are some unclear parts in pattern 2, but all the characters can be read without any problems in pattern 1. C: Both patterns 1 and 2 had unclear areas.

[0202] (Mount payout ability of composite sheet for forming protective film) The composite sheet for forming a protective film of each example and comparative example was wound into a sheet roll. The sheet roll was stored at room temperature (23°C) for 3 days. After storage, the composite sheet for forming a protective film was unwound from the sheet roll, the release film was peeled off, and the unwound composite sheet for forming a protective film was attached to a silicon wafer (350 μm thick, 8 inches in outer diameter) and a ring frame using an attachment device (RAD-2700, manufactured by Lintec Corporation). The workability regarding unwinding failures during attachment was evaluated using the following three-point scale. Unwinding failures were defined as when partial peeling occurred between the adhesive layer and the film for forming a protective film when unwinding the composite sheet for forming a protective film, resulting in the support sheet being transferred to the release film, or when the composite sheet for forming a protective film could not be unwound at all. The results are shown in Table 1. A: 50 sheets are applied and there is one or less sheet that is not properly fed. B: 50 sheets are applied, and there are 2 to 5 sheets with feeding defects. C: 50 sheets applied, 6 or more sheets have feeding problems

[0203] [Table 1]

[0204] From Table 1, it was confirmed that when the gloss value and surface properties of the main surface of the support sheet substrate on which the adhesive layer is not formed are controlled as described above, it is possible to achieve both payout performance and laser marking visibility. [Explanation of symbols]

[0205] 1...Support sheet 2...Base material 3...Adhesive layer 10...Composite sheet for forming protective film 4...Protective film forming film 5...Adhesive layer for jig 70...Chip with protective film 40…Protective film

Claims

1. A substrate and a pressure-sensitive adhesive layer formed on one main surface of the substrate, In the base material, the arithmetic mean height Sa1 of a 4.91 mm × 4.90 mm square region on the main surface on which the pressure-sensitive adhesive layer is not formed is greater than 0.50 μm, the 4.91 mm × 4.90 mm square region on the main surface on which the pressure-sensitive adhesive layer is not formed is a wide region obtained by combining 300 narrow regions, each of which is a 0.36 mm × 0.27 mm square region; When the average of the arithmetic mean heights of the 20 smallest of the arithmetic mean heights of each narrow region is defined as Sa2, Sa2 is 0.43 μm or less, A support sheet having a gloss value of 20 or more at an incident angle of 60° on the main surface on which the pressure-sensitive adhesive layer is not formed.

2. A substrate and a pressure-sensitive adhesive layer formed on one main surface of the substrate, In the base material, the arithmetic mean height Sa1 of a 4.91 mm × 4.90 mm square region on the main surface on which the pressure-sensitive adhesive layer is not formed is greater than 0.50 μm, the 4.91 mm × 4.90 mm square region on the main surface on which the pressure-sensitive adhesive layer is not formed is a wide region obtained by combining 300 narrow regions, each of which is a 0.36 mm × 0.27 mm square region; When the average of the 20 smallest arithmetic mean heights of the respective narrow regions is defined as Sa2, the ratio of Sa1 to Sa2, Sa1 / Sa2, is 1.40 or more, A support sheet having a gloss value of 20 or more at an incident angle of 60° on the main surface on which the pressure-sensitive adhesive layer is not formed.

3. The support sheet according to claim 1 or 2, wherein no other layer is formed on the main surface on which the pressure-sensitive adhesive layer is not formed.

4. A composite sheet for forming a protective film, comprising: the support sheet according to claim 1; and a protective film-forming film formed on the pressure-sensitive adhesive layer of the support sheet.

5. A kit comprising the support sheet according to any one of claims 1 to 3 and a protective film-forming film to be attached to the surface of the adhesive layer of the support sheet.

6. a step of unwinding and unwinding the support sheet according to any one of claims 1 to 3 wound in a roll; A step of attaching the unwound support sheet to a workpiece; A step of laser marking the workpiece; and processing the workpiece to obtain a processed product of the workpiece.

7. a step of unwinding and unwinding the composite sheet for forming a protective film according to claim 4 wound in a roll; A step of attaching the protective film-forming film of the unwound protective film-forming composite sheet to the back surface of the workpiece; A step of converting the attached protective film-forming film into a protective film; A step of performing laser marking on the protective film or the protective film-forming film; A method for manufacturing an apparatus, comprising: a step of dividing the workpiece having a protective film or protective film-forming film on the back surface into individual pieces to obtain a plurality of workpieces with protective films or protective film-forming films.

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