Method for manufacturing protective film forming film, protective film forming sheet, protective film forming composite sheet and apparatus

Abstract

This invention provides a protective film forming film that provides good separability of the workpiece with a protective film and can suppress poor appearance of the protective film after separation, a protective film forming sheet having the protective film forming film, a protective film forming composite sheet, and a method for manufacturing devices such as semiconductor devices. The protective film forming film is a protective film forming film that becomes a protective film after curing. Specifically, when the cured protective film forming film is subjected to a right-angle tear test at 23°C, its right-angle tear strength is 10 N / mm or more, and in the right-angle tear test, the elongation at break of the cured protective film forming film is 10% or less.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a protective film forming film, a protective film forming sheet, a protective film forming composite sheet, and an apparatus. In particular, it relates to a method for manufacturing a protective film forming film suitable for protecting workpieces such as semiconductor wafers or processed objects such as semiconductor wafers obtained by processing workpieces, a protective film forming sheet and a protective film forming composite sheet having the protective film forming film, and an apparatus having a semiconductor wafer, etc. Prior Technology

[0002] In recent years, semiconductor devices have been manufactured using a mounting method called flip-chip bonding. In this method, when mounting a semiconductor wafer with circuit surfaces having bumps or other convex electrodes, the semiconductor wafer is flipped (face down) so that the circuit surfaces of the semiconductor wafer are facing the wafer mounting surface of the substrate, thereby wirelessly bonding the circuit surfaces of the semiconductor wafer to the wafer mounting surface of the substrate. Therefore, the side of the semiconductor wafer opposite to the circuit surface (the side without circuitry, hereinafter also referred to as the back side) is exposed to the outside.

[0003] If the back side of a semiconductor wafer is exposed to the outside, it may chip or break due to impacts during transportation or other processes in subsequent steps. Therefore, in order to protect the semiconductor wafer from such chipping, a hard resin film made of organic materials is often formed on the back side of the semiconductor wafer as a protective film.

[0004] This protective film is formed by curing an uncured resin film (hereinafter also called a protective film forming film) that serves as its precursor. The protective film forming film is attached to the back side of a semiconductor wafer. Before or after the protective film forming film is cured, the semiconductor wafer and the protective film forming film or protective film are cut and segmented (monodivided) into multiple small pieces. In the case where the protective film forming film is not cured, it is cured after segmentation. The resulting segmented pieces are semiconductor wafers with a protective film on the back side (semiconductor wafers with a protective film).

[0005] As a method for individualizing workpieces such as semiconductor wafers by cutting, in addition to blade cutting which involves cutting the workpiece by using a rotating blade while spraying liquid for cleaning and cooling purposes, stealth cutting (a registered trademark) is also known.

[0006] For stealth cutting, firstly, a laser is focused on the interior of the workpiece to create a modified region along a predetermined dividing line. This modified region is where laser irradiation reduces its intensity compared to other areas, causing cracks to form along the workpiece's thickness. Next, a tensile force is applied to the workpiece with the modified region, perpendicular to the thickness direction. This tensile stress extends the cracks in the modified region to the two main surfaces of the workpiece. Finally, the workpiece is divided into multiple small pieces (individualized pieces) along the predetermined dividing line.

[0007] As a method for applying tensile force to a workpiece, an example is the following method: placing a workpiece with a stretchable tape or sheet attached to it on a worktable and stretching (expanding) the tape or sheet in a direction perpendicular to the thickness direction of the workpiece.

[0008] At this time, tensile stress will also be generated on the protective film formed on the back of the workpiece. It is necessary to divide the protective film into a shape that is roughly the same as the shape of the wafer while dividing the workpiece.

[0009] As an example of a protective film forming film that can be properly divided along with the wafer during stealth cutting, Patent Document 1 discloses a protective film forming film in which the product of fracture stress and fracture strain at 0°C is within a specified range. Existing technical documents Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2016-115943 Summary of the Invention

[0011] The technical problem to be solved by the present invention

[0012] However, it has the following problem: even when tensile stress is generated on the workpiece due to expansion, it fails to be segmented along the predetermined dividing line, resulting in the inability to obtain the required number of wafers with protective films, thus reducing the wafer yield. The main reason for this problem is believed to be that the protective film is not properly segmented during expansion. To address this, a low-temperature expansion method (cold expansion) has been proposed to facilitate the segmentation of the protective film; however, this method requires considerable time and energy to cool the expansion device and other components to a low temperature.

[0013] Furthermore, the inventors of this application discovered that when the strength of the protective film is reduced to make it easier to split, the protective film may sometimes be accidentally split due to impacts or other factors applied before expansion. When the protective film is split not due to expansion, but due to impacts or other factors, there is a tendency for the outer perimeter of the protective film to appear as a jagged line rather than a straight line when viewed from above. Wafers with jagged outer perimeters of such protective films are considered to have poor appearance, resulting in a decrease in wafer yield.

[0014] The present invention was made in view of the above-mentioned actual situation, and its object is to provide a protective film forming film that has good separability of the workpiece with a protective film and can suppress the appearance defects of the protective film after separation, a protective film forming sheet having the protective film forming film, a protective film forming composite sheet, and a method for manufacturing devices such as semiconductor devices. Technical means to solve technical problems

[0015] The technical solution of the present invention is as follows. (1) A protective film forming film, which becomes a protective film after curing, wherein when the cured protective film forming film is subjected to a right-angle tear test at 23°C, the right-angle tear strength is 10 N / mm or more, and in the right-angle tear test, the elongation of the cured protective film forming film at the time of breakage is 10% or less. (2) A protective film is formed according to (1), wherein the protective film is a thermosetting material or an energy ray curing material. (3) A protective film is formed according to (1) or (2), wherein the right-angle tear strength is less than 25 N / mm. (4) A protective film forming film according to any one of (1) to (3), which is used to form a modified region by focusing a laser onto the protective film. (5) A protective film forming sheet having a protective film forming film as described in any one of (1) to (4) and a peeling film disposed on at least one main surface of the protective film forming film in a peelable manner. (6) A composite sheet for forming a protective film, having a protective film forming film as described in any one of (1) to (4) and a support sheet for supporting the protective film forming film. (7) The composite sheet for forming a protective film according to (6), wherein when the right-angle tear strength of the protective film formed after curing at 23°C is set as TS1, and the right-angle tear strength of the support sheet when a right-angle tear test is performed on the support sheet at 23°C is set as TS2, TS1 / TS2 is 0.15 or less. (8) A method for manufacturing an apparatus, comprising: The step of forming a protective film and attaching it to the back of the workpiece; The step involves curing the applied protective film to form a protective film on the back of the workpiece, thereby obtaining a workpiece with a protective film attached. The step of focusing a laser onto a pre-defined area inside the workpiece to form the first modified region; The step of focusing a laser onto a pre-defined area inside a protective film to form a second modified region; and The step of applying tensile force to a workpiece with a protective film formed on the first modified region and the second modified region, thereby monolithically processing the workpiece with the protective film to obtain a plurality of workpieces with protective films. (9) The manufacturing method of the device according to (8), wherein the protective film forming film is the protective film forming film of the protective film forming sheet of (5), or the protective film forming film of the protective film forming composite sheet of (6) or (7). Invention Effects

[0016] According to the present invention, a protective film forming film with good separability of the workpiece with a protective film and capable of suppressing poor appearance of the protective film after separation, a protective film forming sheet having the protective film forming film and a protective film forming composite sheet, and a semiconductor device and other devices can be manufactured. Simple Explanation of the Diagram

[0017] Figure 1 is a cross-sectional schematic diagram of an example of a workpiece with a protective film formed by the curing of a protective film of the present embodiment on the back side of the workpiece. Figure 2 is a cross-sectional schematic diagram of an assembly of wafers with protective films, which are formed by individual components of the workpiece with protective films. Figure 3 is a partial planar schematic diagram of an assembly of wafers with protective films, assembled from individual wafers, viewed from direction III as shown in Figure 2. Figure 4 is a cross-sectional schematic diagram of an example of a protective film forming sheet according to this embodiment. Figure 5 is a cross-sectional schematic diagram of an example of a composite sheet for forming a protective film according to this embodiment. Figure 6A is a cross-sectional schematic diagram illustrating the step of attaching the protective film forming sheet of this embodiment to the back of the workpiece. Figure 6B is a cross-sectional schematic diagram illustrating the step of attaching the composite sheet for forming the protective film of this embodiment to the back of the workpiece. Figure 7 is a cross-sectional schematic diagram illustrating the steps of forming a protective film by curing a protective film that has been attached to the back of the workpiece. Figure 8 is a cross-sectional schematic diagram illustrating the steps of forming modified regions inside the workpiece and the protective film. Figure 9 is a cross-sectional schematic diagram illustrating the steps for expanding a workpiece with a protective film forming a modified region. Figure 10 is a cross-sectional schematic diagram illustrating the steps of picking up a protective film wafer from an assembly of individually formed protective film wafers. Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings, based on specific embodiments. First, the main terms used in this specification will be explained.

[0019] The workpiece is a plate-shaped body to be processed, on which the protective film forming sheet or protective film forming composite sheet of this embodiment is attached. Examples of workpieces include wafers and panels. Specifically, semiconductor wafers and semiconductor panels are examples. Examples of processed workpieces include wafers obtained by unitizing wafers. Specifically, semiconductor wafers obtained by unitizing semiconductor wafers are examples.

[0020] The "surface" of a workpiece such as a wafer refers to the side where circuits, bumps, or other convex electrodes are formed, while the "back side" refers to the side where no circuits or electrodes (such as bumps or other convex electrodes) are formed. A protective film is formed on the back side of the wafer and the chip.

[0021] Wafer segmentation refers to dividing a wafer into individual circuits to obtain a wafer.

[0022] In this specification, for example, "(meth)acrylate" refers to the term used to refer to both "acrylate" and "methacrylate", and other similar expressions are the same.

[0023] "Energy rays" refer to ultraviolet rays, electron beams, etc., with ultraviolet rays being preferred.

[0024] A release film is a film that supports an adhesive layer or protective film in a peelable manner to form a membrane. The term "film" is used to encompass the concept of a sheet and is not limited to its thickness.

[0025] The mass ratios in the descriptions of compositions such as protective film forming compositions are based on the active ingredient (solid content) and do not include solvent unless otherwise specified.

[0026] (1. Protective film formation) The protective film forming film of this embodiment can be used to form a protective film that is attached to a workpiece and used to protect the workpiece or the workpiece being processed.

[0027] (1.1 Protective film) In this embodiment, the protective film can be obtained by curing the protective film forming film of this embodiment. That is, the protective film forming film of this embodiment is curable. By overlapping the curable protective film forming film with the workpiece and then curing the protective film forming film, the protective film can be firmly bonded to the workpiece, forming a durable protective film.

[0028] The protective film is a cured product of the protective film forming film, and is different from the protective film forming film. Examples of cured products include thermosetting products and energy ray curing products. In this embodiment, the protective film is preferably a thermosetting product.

[0029] Whether a protective film is thermosetting can be determined as follows: First, the protective film formed at room temperature (23°C) is heated to a temperature higher than room temperature, and then cooled to room temperature, thus forming a heated and cooled protective film. Next, at the same temperature, the hardness of the heated and cooled protective film is compared with the hardness of the protective film formed before heating. If the heated and cooled protective film is harder, then the protective film is determined to be thermosetting.

[0030] Furthermore, it is preferable that the protective film forming film has adhesiveness at room temperature (23°C) or develops adhesiveness by heating. Therefore, when the protective film forming film is overlapped with the workpiece, the two can be bonded together. Thus, its position can be accurately determined before the protective film forming film cures.

[0031] The protective film can consist of a single layer or multiple layers. When the protective film has multiple layers, these multiple layers can be the same as each other or different from each other, and there are no particular restrictions on the combination of the layers that make up these multiple layers.

[0032] In this embodiment, it is preferable that the protective film forming film is a single layer. Since a single-layer protective film can be obtained with high precision thickness, it is easy to manufacture. Furthermore, if the protective film forming film consists of multiple layers, the adhesion between layers and the elasticity of each layer must be considered, and there is a risk of peeling off from the substrate. When the protective film forming film is a single layer, the above-mentioned risks can be reduced, and the design freedom is increased. In addition, the risk of interlayer peeling due to differences in thermal expansion and contraction between layers can be reduced in steps where temperature changes occur (during reflow soldering or when using the apparatus).

[0033] There is no particular limitation on the thickness of the protective film, but it is preferably 100 μm or less, 70 μm or less, 45 μm or less, or 30 μm or less. Furthermore, the thickness of the protective film is preferably 5 μm or more, 10 μm or more, or 15 μm or more. If the thickness of the protective film is within the above range, the resulting protective film has good protective performance.

[0034] In addition, the thickness of the protective film refers to the overall thickness of the protective film. For example, the thickness of a protective film composed of multiple layers refers to the total thickness of all the layers that make up the protective film.

[0035] In this embodiment, a protective film is formed by attaching the film to the workpiece and curing it. Ultimately, a workpiece with a cured protective film (a workpiece with a protective film) is obtained.

[0036] Figure 1 shows a workpiece 100 with a protective film. The workpiece 100 with the protective film has a protective film 1 formed on the back side (lower side in Figure 1) of the workpiece 6, and a convex electrode 6b formed on the surface side (upper side in Figure 1) of the workpiece 6. A circuit is formed on the surface side of the workpiece 6, and the convex electrode 6b is formed in a manner electrically connected to the circuit. Examples of convex electrodes 6b include bumps, pillar electrodes, etc.

[0037] In this embodiment, the workpiece 100 with the protective film is mounted on a stretchable tape or sheet, such as a cutting tape or cutting disc, with the main surface of the protective film 1 opposite to that of the workpiece 6 as the main surface.

[0038] In stealth cutting, firstly, a predetermined laser is focused on the interior of the workpiece, forming a modified region along a pre-defined dividing line. Then, a stretchable tape or sheet is stretched (expanded) by applying tensile force to the workpiece 6 in a direction toward its outer periphery. This tensile stress causes cracks generated in the modified region to extend to both main surfaces of the workpiece. Finally, the workpiece is divided into multiple small pieces (monolithically processed) along the pre-defined dividing line, resulting in the finished workpiece.

[0039] At this time, tensile stress is also generated on the protective film, causing the protective film to be stretched and then divided into shapes corresponding to the predetermined dividing lines. Therefore, through this expansion, the workpiece 100 with a protective film shown in FIG1 is divided, and as shown in FIG2, a plurality of wafers 100a with protective films are obtained as workpieces. The wafers 100a with protective films have a protective film 1 formed on the back side (lower side in FIG2) of the wafer 6a, and a convex electrode 6b formed on the surface side (upper side in FIG2) of the wafer 6a.

[0040] However, sometimes, even if tensile stress from expansion occurs on the workpiece with the protective film, it may not be divided along the predetermined dividing line, resulting in the inability to obtain the required number of wafers with the protective film. Figure 3 is a diagram showing the planar shape of the wafer 100a with the protective film obtained by expansion in Figure 2, viewed from direction III. That is, Figure 3 shows the planar shape of the wafer 100a with the protective film when viewed from direction III.

[0041] In the upper left of Figure 3, there is an undivided, undivided, protective-film-attached wafer 101a that should be divided along the predetermined dividing line 200. Since this undivided, protective-film-attached wafer 101a is a defective product, it results in a reduced wafer yield.

[0042] In the past, to address this issue, cold expansion was employed, which involved extending the stealth cut at low temperatures (e.g., below 0°C). However, the time and energy required for cooling became problematic.

[0043] In this embodiment, a modified region is formed not only inside the workpiece but also inside the protective film, along the predetermined dividing line. By forming the modified region inside the protective film, even when performing stealth cutting at room temperature (e.g., 23°C), the workpiece with the protective film can be reliably divided along the predetermined dividing line, and a predetermined number of wafers with the protective film can be obtained.

[0044] However, when a modified region forms inside the protective film, resulting in a region with reduced strength, the protective film may be accidentally split due to an impact or other event before expansion, rather than due to expansion. When the protective film is split due to an impact or other event, as shown in the lower right of Figure 3, there is a tendency to obtain a wafer 102a with a protective film where the outer perimeter of the protective film appears jagged rather than straight when viewed from above. Such a wafer 102a with a protective film is considered to have poor appearance, leading to a decrease in wafer yield.

[0045] To suppress this appearance defect, in addition to forming modified regions in the protective film, the breaking strength (right-angle tear strength) and elongation at break during the right-angle tear test of the protective film are controlled as follows. As mentioned above, the protective film is a cured form of the protective film forming film, the right-angle tear strength of the protective film is synonymous with the right-angle tear strength of the cured protective film forming film, and the elongation at break of the protective film is synonymous with the elongation at break of the cured protective film forming film.

[0046] (1.1.1 Right-angle tear strength) In this embodiment, the right-angle tear strength (TS1) of the cured protective film (protective film) is 10 N / mm or higher at 23°C. By keeping the right-angle tear strength within the above range, accidental splitting of the protective film due to impacts applied before expansion can be suppressed. Therefore, the protective film will not be split before the stealth cut expansion, and it can be reliably and properly split even when expansion is carried out at room temperature, resulting in a predetermined number of wafers with the protective film having a straight outer perimeter when viewed from above.

[0047] Preferably, the right-angle tear strength (TS1) of the cured protective film is 13 N / mm or more, more preferably 15 N / mm or more, and even more preferably 17 N / mm or more.

[0048] On the other hand, in order to more reliably divide the protective film during expansion, the right-angle tear strength (TS1) of the cured protective film at 23°C is preferably 25 N / mm or less, and more preferably 22 N / mm or less.

[0049] The right-angle tear strength (TS1) of the cured protective film was determined according to JIS K 7128-3:1998. That is, the right-angle tear strength of the cured protective film was determined in the same manner as the test method (right-angle tear method) specified in JIS K 7128-3:1998, although the test conditions may differ. Specific test methods will be described in the examples. The test piece has the shape shown in Figure 2 of JIS K 7128-3:1998, with a 90° concave shape in the center. The right-angle tear test was performed by stretching both ends of the test piece.

[0050] (1.1.2 Elongation at fracture) In this embodiment, at 23°C, in the test measuring the right-angle tear strength, the elongation at break of the cured protective film (protective film) is 10% or less. By keeping the elongation within the above range, the protective film can be appropriately divided even when expanded at room temperature, and a predetermined number of protective film wafers with a straight outer perimeter when viewed from above can be obtained.

[0051] The elongation at which the cured protective film breaks is preferably 8% or less, more preferably 7% or less, and even more preferably 4% or less. On the other hand, there is no particular limitation on the lower limit of the elongation, but from the viewpoint of reducing the risk of cracks or defects occurring outside the outer perimeter of the protective film when viewed from above during expansion, it is preferably 0.2% or more.

[0052] As described above, since the elongation at break of the cured protective film is the measured value in the test for determining the right-angle tear strength shown in (1.1.1), this elongation is determined according to JIS K 7128-3:1998. That is, the right-angle tear strength of the cured protective film is determined in the same manner as the test method specified in JIS K 7128-3:1998, although the test conditions may differ. Specific test methods will be described in the examples.

[0053] (1.2 Composition for forming protective film) As long as the protective film possesses the aforementioned 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 (the composition for forming the protective film) is preferably a resin composition containing at least a polymer component (A), a curing component (B), and a filler material (E). The polymer component is considered to be a component formed by the polymerization reaction of a polymeric compound. Furthermore, the curing component is a component capable of undergoing a curing (polymerization) reaction. In addition, in this invention, the polymerization reaction also includes a condensation polymerization reaction.

[0054] Furthermore, components contained in the polymer composition may sometimes also be curable components. In this embodiment, when the protective film forming composition contains such a component that is both a polymer component and a curable component, it is considered that the protective film forming composition contains both a polymer component and a curable component.

[0055] (1.2.1 Polymer composition) The polymer component (A) imparts film-forming properties (film-forming ability) to the protective film while also providing it with appropriate tack, ensuring uniform adhesion of the protective film to the workpiece. The weight-average molecular weight of the polymer component is typically 50,000 to 2,000,000, preferably 100,000 to 1,500,000, and most preferably in the range of 200,000 to 1,000,000. Examples of such polymer components include acrylic resins, urthane resins, phenoxy resins, silicone resins, and saturated polyester resins, with acrylic resins being particularly preferred.

[0056] In addition, unless otherwise specified in this specification, "weight-average molecular weight" refers to the converted value of polystyrene determined by gel permeation chromatography (GPC). The determination based on this method is carried out, for example, as follows: using a high-speed GPC apparatus "HLC-8120GPC" manufactured by TOSOH CORPORATION, with high-speed columns "TSK guard column H XL-H", "TSK Gel GMH XL", and "TSK Gel G2000 H XL" (all manufactured by TOSOH CORPORATION) connected in sequence, under the conditions of column temperature of 40°C and liquid feed rate of 1.0 mL / min, a differential refractive index detector is used as the detector.

[0057] Examples of acrylic resins include copolymers of (meth)acrylates composed of (meth)acrylate monomers and structural units derived from (meth)acrylate derivatives. Among these, alkyl (meth)acrylate monomers with 1 to 18 carbon atoms in the alkyl group are preferred examples, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and butyl (meth)acrylate. Furthermore, examples of (meth)acrylate derivatives include (meth)acrylate, glycidyl (meth)acrylate, and hydroxyethyl (meth)acrylate.

[0058] In this embodiment, in order to control the adhesion or adhesiveness of the workpiece, it is preferable to introduce hydroxyl groups into the acrylic resin using hydroxyl ester or the like.

[0059] The preferred glass transition temperatures of acrylic resin are -70℃~40℃, -60℃~30℃, -50℃~25℃, -40℃~20℃, and -35℃~15℃. By setting the glass transition temperature of the acrylic resin within these ranges, it is possible to moderately increase the viscosity of the protective film while simultaneously improving the adhesion of the protective film to the workpiece. Furthermore, it is easier to set the right-angle tear strength and elongation at break in the right-angle tear test within the aforementioned ranges while also moderately increasing the adhesion of the protective film to the workpiece.

[0060] When an acrylic resin has m types of structural units (m being an integer greater than or equal to 2), the glass transition temperature of the acrylic resin can be calculated in the following way. That is, when the m monomers that derive the structural units in the acrylic resin are assigned arbitrary, non-repeating numbers 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.

[0061] [Mathematical Expression 1] In the formula, Tg is the glass transition temperature of acrylic resin; m is an integer greater than or equal to 2; Tgk is the glass transition temperature of the homopolymer of monomer m; Wk is the mass fraction of structural unit m derived from monomer m in acrylic resin, and Wk satisfies the following formula.

[0062] [Mathematical Expression 2] In the formula, m and Wk are the same as those mentioned above.

[0063] The Tgk value can be found in polymer datasheets, adhesion manuals, or polymer handbooks. For example, the Tgk of methyl acrylate homopolymer is 10°C, the Tgk of n-butyl acrylate homopolymer is -54°C, the Tgk of methyl methacrylate homopolymer is 105°C, the Tgk of 2-hydroxyethyl acrylate homopolymer is -15°C, the Tgk of glycidyl methacrylate homopolymer is 41°C, the Tgk of 2-ethylhexyl acrylate homopolymer is -70°C, and the Tgk of ethyl acrylate homopolymer is -24°C.

[0064] When the total weight of the composition for forming the protective film is set to 100 parts by weight, the content of the polymer component is preferably 5-60 parts by weight, 10-50 parts by weight, 13-40 parts by weight, or 16-30 parts by weight. By keeping the polymer component content within the above ranges, it is easier to keep the right-angle tear strength and elongation at break within the above ranges in the right-angle tear test. Furthermore, it is easier to control the adhesion of the protective film formed.

[0065] (1.2.2 Thermosetting components) The curing component (B) forms a protective film as a cured product by forming a protective film through film curing. As mentioned above, the protective film is preferably a thermosetting material or an energy-curing material, and the curing component can be a thermosetting material, an energy-curing material, or a mixture thereof.

[0066] The protective film formed in this embodiment has reduced light transmittance because it contains filler materials and colorants, as described later. The energy-curable protective film is cured by irradiation with energy rays; therefore, for example, when the thickness of the protective film increases, the curing caused by energy rays tends to become insufficient.

[0067] However, for thermosetting protective film formation films, even if their thickness increases, they can be fully cured by heating, thus forming a protective film with high protective performance. In addition, by using conventional heating methods such as heating ovens, multiple protective film formation films can be heated together to achieve thermosetting.

[0068] Since the protective film is preferably a thermosetting material, the curing components contained in the protective film forming film are preferably thermosetting. That is, the protective film forming film of this embodiment is preferably thermosetting.

[0069] As thermosetting components, epoxy resins, thermosetting polyimide resins, unsaturated polyester resins, and mixtures thereof are preferred. Furthermore, thermosetting polyimide resins refer to a general term for low molecular weight and low-viscosity monomer or precursor polymers that form polyimide resins by thermosetting. Non-limiting specific examples of thermosetting polyimide resins are described, for example, in the Journal of the Fiber Society (Journal of the Fiber Society), "Fibers and Industry," Vol. 50, No. 3 (1994), pp. 106-118.

[0070] Epoxy resins, as thermosetting components, possess the property of transforming into a three-dimensional network upon heating, thereby forming a robust coating. Various known epoxy resins can be 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. Furthermore, 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.

[0071] Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenylphenolic varnish, and cresol phenolic varnish; 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-type or alkyl-glycidyl-type epoxy resins formed by replacing the active hydrogen bonded to the nitrogen atom with glycidyl groups in aniline isocyanurate, etc.; and so-called alicyclic epoxides, such as vinylcyclohexane diepoxide, 3,4-epoxycyclohexylmethyl-3,4-dicyclohexane carboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-me-dioxane, which introduce epoxy groups by oxidizing the carbon-carbon double bonds within the molecule. Alternatively, epoxy resins with biphenyl backbone, dicyclohexadiene backbone, naphthalene backbone, etc., can also be used.

[0072] When a thermosetting component is used as the curing component (B), it is preferable to simultaneously use a curing agent (C) as an auxiliary agent. For epoxy resins, a heat-active latent epoxy resin curing agent is preferred. "Heat-active latent epoxy resin curing agent" refers to a type of curing agent that does not readily react with epoxy resin at room temperature (23°C), but is activated by heating to a certain temperature and thus reacts with epoxy resin. Activation methods for heat-active latent epoxy resin curing agents include: methods that utilize a heating-based chemical reaction to generate active species (anions, cations); methods that are stably dispersed in epoxy resin near room temperature, but are compatible with epoxy resin at high temperatures, dissolve, and initiate a curing reaction; methods that utilize a molecular sieve-sealed curing agent, dissolving at high temperatures and initiating a curing reaction; and methods using microcapsules, etc.

[0073] In the methods described, a preferred method is one in which the material is stably dispersed in epoxy resin near room temperature, but is compatible with epoxy resin at high temperatures, dissolves, and initiates a curing reaction.

[0074] Specific examples of thermoactive latent epoxy resin curing agents include various onium salts, dicarboxylic acid diacetylhydrazine compounds, dicyandiamide, amine adduct curing agents, imidazole compounds, and other high-melting-point active hydrogen compounds. These thermoactive latent epoxy resin curing agents can be used alone or in combination of two or more. In this embodiment, dicyandiamide is particularly preferred.

[0075] Furthermore, phenolic resins are also preferred as curing agents for epoxy resins. As phenolic resins, condensates of phenols and aldehydes, such as alkylphenols, polyphenols, and naphthols, can be used without particular restriction. Specifically, phenolic varnish resins, o-cresol varnish resins, p-cresol varnish resins, tributylphenol varnish resins, dicyclopentadiene cresol resins, poly(p-vinylphenol) resins, bisphenol A type phenolic varnish resins, or modified versions thereof can be used.

[0076] The phenolic hydroxyl groups contained in these phenolic resins can easily undergo an addition reaction with the epoxy groups of the aforementioned epoxy resins by heating, thereby forming a cured product with high impact resistance.

[0077] The preferred content of curing agent (C) relative to 100 parts by weight of epoxy resin is 0.5 to 100 parts by weight, 0.8 to 20 parts by weight, 1.2 to 8 parts by weight, or 1.6 to 4 parts by weight. By keeping the content of curing agent (C) within the above ranges, the network structure of the protective film becomes denser. Therefore, it is easier to obtain the performance of protecting the workpiece as a protective film, and it is easier to keep the right-angle tear strength and elongation at break in the right-angle tear test within the above ranges.

[0078] When dicyandiamide is used as a curing agent (C), it is preferable to further use a curing accelerator (D) simultaneously. As a curing accelerator, preferably, it is an imidazole class (imidazole formed by replacing one or more hydrogen atoms with groups other than hydrogen atoms), such as 2-methylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium. Of particular, 2-phenyl-4,5-dihydroxymethylimidazolium is especially preferred.

[0079] The preferred content of the curing accelerator relative to 100 parts by weight of epoxy resin is 0.5 to 10 parts by weight, 0.8 to 7 parts by weight, 1.2 to 5 parts by weight, or 1.6 to 4 parts by weight. By keeping the content of the curing accelerator (D) within the above range, the network structure of the protective film becomes denser. Therefore, it is easier to obtain the performance of protecting the workpiece as a protective film, and it is easier to keep the right-angle tear strength and elongation at break in the right-angle tear test within the above range.

[0080] When the total weight of the composition for forming the protective film is set to 100 parts by weight, the total content of the thermosetting component and the curing agent is preferably 6-80 parts by weight, 8-70 parts by weight, 10-60 parts by weight, 12-50 parts by weight, and 14-40 parts by weight. By keeping the total content of the thermosetting component and the curing agent at or above the lower limit of the above values, appropriate tackiness can be exhibited before curing, allowing for stable application. Furthermore, after curing, the protective film easily provides the performance of protecting the workpiece. By adjusting the degree of curing within the above ranges, it is easier to keep the right-angle tear strength and elongation at break in the right-angle tear test within the above ranges.

[0081] (1.2.3 Energy-based components that can be solidified) When the curing component (B) is an energy-curing component, the energy-curing component is preferably uncured, preferably adhesive, and more preferably uncured and adhesive.

[0082] Energy-curable components are those that are cured by irradiation with energy rays, and are also used to impart film-forming properties, flexibility, etc., to protective films.

[0083] As an energy-curing component, it is preferably a compound having an energy-curing group. Examples of such compounds include those known to have energy-curing groups.

[0084] (1.2.4 Filler Material) By including a filler material (E) in the protective film forming film, it becomes easier to adjust the coefficient of thermal expansion of the resulting protective film. By making this coefficient of thermal expansion close to that of the workpiece, the bonding reliability of the wafer with the protective film attached is further improved. Furthermore, by including a filler material (E) in the protective film forming film, a rigid protective film can be obtained, further reducing the moisture absorption rate of the protective film and further improving the bonding reliability of the wafer with the protective film attached.

[0085] The filler material (E) can be either an organic filler material or an inorganic filler material, but from the viewpoint of shape stability at high temperatures, an inorganic filler material is preferred.

[0086] Preferred inorganic filler materials include, for example, powders of silicon dioxide, alumina, talc, calcium carbonate, red iron oxide, silicon carbide, boron nitride, etc.; beads obtained by forming these inorganic filler materials into spherical shapes; surface-modified versions of these inorganic filler materials; single-crystal fibers of these inorganic filler materials; glass fibers, etc. Among these, silicon dioxide and surface-modified silicon dioxide are preferred. Surface-modified silicon dioxide is preferably surface-modified using a coupling agent, and more preferably using a silane coupling agent.

[0087] The average particle size of the filler material is preferably 0.02~10μm, 0.05~5μm, or 0.10~3μm.

[0088] By setting the average particle size range of the filler material to the range described above, the operability of the composition for forming a protective film becomes good. As a result, the quality of the composition for forming a protective film and the protective film formed is easily stabilized.

[0089] In addition, unless otherwise specified in this specification, "average particle size" refers to the particle size (D50) at which the cumulative value in the particle size distribution curve obtained by laser diffraction scattering is 50%.

[0090] When the total weight of the composition for forming the protective film is set to 100 parts by weight, the content of the filler material is preferably 15-80 parts by weight, 30-75 parts by weight, 40-70 parts by weight, or 45-65 parts by weight.

[0091] By setting the lower limit of the filler content to the aforementioned value, the bonding reliability of the wafer with the protective film obtained by forming the protective film is further improved. Furthermore, by setting the upper limit of the filler content to the aforementioned value, the adhesion of the protective film to the workpiece is increased, and the adhesive force of the protective film to the workpiece is moderately increased. Moreover, by keeping the filler content within the aforementioned range, it is easier to ensure that the right-angle tear strength and elongation at break in the right-angle tear test are within the aforementioned range.

[0092] (1.2.5 Coupling agent) The protective film forming film preferably contains a coupling agent (F). By containing a coupling agent, after the protective film has cured, the adhesion between the protective film and the workpiece can be improved without compromising the heat resistance of the protective film, while also improving water resistance (damp heat resistance). From the viewpoint of versatility and cost advantage, a silane coupling agent is preferred as the coupling agent.

[0093] Examples of silane coupling agents include γ-glycidyl etheroxypropyltrimethoxysilane, γ-glycidyl etheroxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-(methacryloxypropyl)trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane, and N-6-(aminoethyl)-γ-aminopropyltrimethoxysilane. Ethyl)-γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureapropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(3-triethoxypropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, imidazolesilane, etc.

[0094] As a preferred silane coupling agent, oligomeric silane coupling agents having a plurality of alkoxysilyl groups in one molecule are also mentioned. Since the oligomeric silane coupling agents are not easily volatile and have a plurality of alkoxysilyl groups in one molecule, they are preferred in terms of effectively improving durability. Examples of oligomeric silane coupling agents include epoxy-containing oligomeric silane coupling agents such as "X-41-1053", "X-41-1059A", "X-41-1056" and "X-40-2651" (all manufactured by Shin-Etsu Chemical Co., Ltd.); and mercapto-containing oligomeric silane coupling agents such as "X-41-1818", "X-41-1810" and "X-41-1805" (all manufactured by Shin-Etsu Chemical Co., Ltd.). These silane coupling agents can be used alone or in combination of two or more.

[0095] When the total weight of the composition for forming the protective film is set to 100 parts by weight, the content of the coupling agent is preferably 0.01 to 20 parts by weight, 0.1 to 10 parts by weight, 0.2 to 5 parts by weight, or 0.3 to 3 parts by weight.

[0096] (1.2.6 Colorants) The protective film is preferably formed by containing a colorant (G). This covers the back side of the workpiece, such as a wafer, thus shielding it from various electromagnetic waves generated within the electronic device and reducing malfunctions of the workpiece.

[0097] As the colorant (G), known colorants such as organic pigments, organic dyes, and inorganic pigments can be used. In this embodiment, inorganic pigments are preferred.

[0098] Inorganic pigments include, for example, carbon black, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide) pigments, and ATO (antimony tin oxide) pigments. Among these, carbon black is particularly preferred. Carbon black can shield electromagnetic waves across a wide wavelength range.

[0099] The amount of colorant (especially carbon black) in the protective film forming film varies depending on the thickness of the protective film forming film. For example, when the thickness of the protective film forming film is 25 μm, the preferred content of colorant when the total weight of the composition for forming the protective film is set to 100 parts by weight is 0.01 to 10 parts by weight, 0.03 to 7 parts by weight, or 0.05 to 4 parts by weight.

[0100] The average particle size of the colorant (especially carbon black) is preferably 1~500nm, 3~100nm, or 5~50nm. If the average particle size of the colorant is within the above range, the transmittance can be easily controlled within the required range.

[0101] (1.2.7 Other additives) The protective film forming composition may contain, without impairing the effects of the present invention, other additives such as photopolymerization initiators, crosslinking agents, plasticizers, antistatic agents, antioxidants, gettering agents, tackifiers, and release agents.

[0102] (2. Sheet for forming protective film) The protective film forming sheet of this embodiment has a protective film forming film and a release film disposed on at least one main surface of the protective film forming film. The release film is peeled off when the protective film forming film is used.

[0103] The protective film forming sheet 51 shown in Figure 4 has the following configuration: a first release film 21 supporting the protective film forming film 10 is disposed on one main surface 10a of the protective film forming film 10, and a second release film 22 is disposed on the other main surface 10b.

[0104] The protective film forming sheet of this embodiment is used to: attach a protective film forming film to the back side of a workpiece before it is individualized, and then cure the protective film forming film to form a protective film on the back side of the workpiece. The workpiece with the protective film formed (the workpiece with the protective film) is individualized by stealth cutting to obtain a wafer with the protective film as a workpiece processing material.

[0105] Furthermore, the sheet for forming the protective film can also be a long strip with a length that is very long in the length direction relative to its width direction. Alternatively, it can be a roll obtained by winding such a long strip.

[0106] Furthermore, the protective film forming sheet can also be a protective film forming sheet that has undergone punching processing in such a way that the protective film forming film to be attached to the workpiece has a specified closed shape. The specified closed shape is not particularly limited, but it is preferably a shape that is approximately the same as that of the workpiece to which it is attached.

[0107] (2.1 Peel-off membrane) A release film is a film that supports a protective film in a peelable manner. A release film can consist of one (single) or two or more substrate layers. From the viewpoint of controlling peelability, the surface of the substrate can also be treated for release. That is, the surface of the substrate can be modified, or a material (release agent layer) not derived from the substrate can be formed on the surface of the substrate.

[0108] As a substrate, there are no particular limitations as long as it is a material that can support the protective film before it is attached to the workpiece. It is usually composed of a film with resin as the main material (hereinafter referred to as "resin film").

[0109] Specific examples of resin membranes include polyethylene membranes, polypropylene membranes, polybutene membranes, polybutadiene membranes, polymethylpentene membranes, polyvinyl chloride membranes, vinyl chloride copolymer membranes, polyethylene terephthalate membranes, polyethylene naphthalate membranes, polybutylene terephthalate membranes, polyurethane membranes, ethylene vinyl acetate copolymer membranes, ionomer resin membranes, ethylene-(meth)acrylate copolymer membranes, ethylene-(meth)acrylate copolymer membranes, polystyrene membranes, polycarbonate membranes, polyimide membranes, and fluoropolymer membranes. Furthermore, cross-linked membranes of these resin membranes can also be used. Further, laminated membranes of these resin membranes can also be used. In this embodiment, from the viewpoints of environmental safety and cost, polyethylene terephthalate membranes are preferred.

[0110] The resin film mentioned above may also contain various additives such as colorants, flame retardants, plasticizers, antistatic agents, lubricants, and fillers.

[0111] The release agent layer can be obtained by applying a coating agent containing a release agent layer composition to one side of a substrate, followed by drying and curing the coating. The release agent layer composition is not particularly limited as long as it is a material capable of imparting a peel-off property between the substrate and the protective film. In this embodiment, the release agent layer composition is preferably, for example, an alkyd release agent, a silicone release agent, a fluorinated release agent, an unsaturated polyester release agent, a polyolefin release agent, or a paraffin release agent, with a silicone release agent being preferred.

[0112] There is no particular limitation on the thickness of the release film, but it is preferably 15~100μm, more preferably 25~80μm, and even more preferably 35~60μm.

[0113] In addition, as shown in Figure 4, when a release film is formed on the two main surfaces of the protective film forming film, it is preferable to set the release force of one release film to be larger and use it as a heavy-release release film, and set the release force of the other release film to be smaller and use it as a light-release release film.

[0114] (3. Composite sheet for forming protective film) The protective film forming composite sheet of this embodiment has the aforementioned protective film forming film and a support sheet supporting the protective film forming film.

[0115] The protective film forming composite sheet of this embodiment is used to: attach the protective film forming film contained in the protective film forming composite sheet to the back of the workpiece before the workpiece is individually formed, and cure the protective film forming film to form a protective film on the workpiece.

[0116] Furthermore, when the workpiece with the protective film formed (the workpiece with the protective film) is individually die-cut using stealth cutting, the support sheet included in the composite sheet for forming the protective film is stretched by applying a tensile force to the workpiece with the modified region. Ultimately, a wafer with the protective film can be obtained as a workpiece.

[0117] Therefore, it is preferable that the support plate has a degree of elasticity capable of achieving a specified amount of expansion, and that it can fit tightly against the workpiece to a degree that can hold the workpiece and allow the tensile force to be transmitted to the workpiece during expansion.

[0118] Specifically, the support sheet is preferably an adhesive sheet having a substrate and an adhesive layer.

[0119] The protective film forming composite sheet 61 shown in Figure 5 has a structure comprising an adhesive sheet 4, a protective film forming film 10, and a clamping adhesive layer 5. The adhesive sheet 4 is formed by depositing an adhesive layer 42 on one surface of a substrate 41. The protective film forming film 10 is deposited on the adhesive sheet 4 on the side of the adhesive layer 42 and is formed with a diameter smaller than that of the adhesive layer 42. The clamping adhesive layer 5 is deposited on the periphery of the adhesive sheet 4, which is closer to the outer edge than the protective film forming film 10. In other words, the adhesive sheet 4 serves as a support sheet. Furthermore, the clamping adhesive layer 5 is a layer used to bond the protective film forming composite sheet 61 to a clamp such as a ring frame.

[0120] (3.1 Adhesive sheet) In this embodiment, an adhesive sheet having a substrate and an adhesive layer will be described as a support sheet.

[0121] (3.1.1 Right-angle tear strength ratio) In this embodiment, when the right-angle tear strength of the support sheet is set as TS2 when the support sheet is subjected to a right-angle tear test at 23°C, the ratio of TS1 (the right-angle tear strength of the protective film formed after curing at 23°C) to TS2, i.e., TS1 / TS2, is preferably 0.15 or less.

[0122] The support sheet needs to have strength sufficient to prevent breakage during expansion. However, the expansion amount is proportional to the force exerted on the support sheet. When TS1 / TS2 is within the aforementioned range, since TS2 is sufficiently large relative to TS1, even with a large expansion amount, the support sheet will not break during expansion and the protective film can be reliably separated. In other words, it can accommodate a wide range of expansion variations and adequately ensure the expansion margin.

[0123] TS1 / TS2 is preferably below 0.125, and even more preferably below 0.116.

[0124] On the other hand, although there is no particular limitation on the lower limit of TS1 / TS2, from the viewpoint of the selectivity of the material constituting the support sheet and the viewpoint of making the outer periphery line of the divided protective film a good straight line, it is preferable to be 0.03 or more, and more preferably 0.06 or more.

[0125] When TS1 / TS2 is outside the aforementioned range, TS2 is lower, meaning that TS2 is not as large relative to TS1. That is, compared to the case where TS1 / TS2 is within the aforementioned range, it means that the support sheet is more prone to breakage during expansion. When the support sheet breaks during expansion, the tensile force becomes unable to act on the workpiece with the protective film, therefore, most of the workpieces with the protective film cannot be segmented. This results in a significant decrease in wafer yield.

[0126] Therefore, sheets made of materials with high TS2 are typically used as support sheets. By achieving a higher TS2, the risk of support sheet breakage can be further reduced even if the support sheet is accidentally placed in a state that is more prone to breakage than usual during use. For example, even sheets made of the same material will break at the point of damage when there are scratches on the sheet, thus making the support sheet more prone to breakage during expansion. However, by achieving a higher TS2 and thus a smaller TS1 / TS2 ratio, it is easier to balance the reduction of support sheet breakage risk with good separability of the protective film. The aforementioned scratches may be caused by impacts during transportation, etc.

[0127] When the support sheet is an adhesive sheet having a substrate and an adhesive layer, the composition of the substrate and the adhesive layer is not particularly limited as long as the TS2 of the adhesive sheet meets the composition of the above-mentioned TS1 / TS2 range.

[0128] (3.1.2. Substrate) The substrate 41 of the adhesive sheet 4 is usually composed of a film (hereinafter referred to as resin film) with resin material as the main component.

[0129] Specific examples of resin films include polyethylene films such as low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and high-density polyethylene (HDPE) films; polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, ethylene-norbornene copolymer films, and norbornene resin films; ethylene copolymer films such as ethylene-vinyl acetate copolymer films, ethylene-(meth)acrylic acid copolymer films, and ethylene-(meth)acrylic acid copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; polyester films such as polyethylene terephthalate films and polybutylene terephthalate films; polyurethane films; polyimide films; polystyrene films; polycarbonate films; and fluoropolymer films. Furthermore, modified films such as cross-linked films and ionomer films of these resin films can also be used. The substrate 41 described above can be a film composed of one of these resin films, or it can be a laminated film formed by further combining two or more of these resin films. In this embodiment, from the viewpoint of extensibility and right-angle tear strength, polypropylene film and polyvinyl chloride film are preferred.

[0130] To improve the adhesion between the resin film and the adhesive layer 42 deposited on the surface of the resin film, surface treatment or primer treatment based on oxidation or texturing methods can be applied to one or both sides of the resin film as needed. Examples of oxidation methods include corona discharge treatment, plasma discharge treatment, chromating treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment. Examples of texturing methods include sandblasting and thermal spraying.

[0131] The resin film mentioned above may also contain various additives such as colorants, flame retardants, plasticizers, antistatic agents, lubricants, and fillers.

[0132] The thickness of the substrate 41 is not particularly limited as long as it can function properly in each step of forming the composite sheet for the protective film. Preferably, it is 20-200 μm; more preferably, 40-170 μm; and most preferably, 50-140 μm.

[0133] (3.1.3. Adhesive layer) The adhesive layer 42 of the adhesive sheet 4 of the protective film forming composite sheet in this embodiment can be composed of a non-energy-curable adhesive or an energy-curable adhesive. As a non-energy-curable adhesive, an adhesive with the desired adhesion and re-peelability is preferred, such as acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives. Among these, acrylic adhesives are preferred from the viewpoint of high adhesion to the protective film forming film 10 and the ability to reliably maintain the wafer with the protective film attached during expansion. Furthermore, acrylic adhesives are also preferred from the viewpoint of easily controlling the pick-up suitability of the wafer with the protective film attached.

[0134] On the other hand, since the adhesive strength of energy-cured adhesives is reduced by irradiation with energy rays, when it is necessary to separate the workpiece or workpiece from the adhesive sheet, it can be easily separated by irradiation with energy rays.

[0135] The energy-curable adhesive constituting the adhesive layer 42 can be a polymer with energy-curable properties as the main component, or a mixture of a polymer without energy-curable properties and monomers and / or oligomers with energy-curable properties as the main component.

[0136] Examples of energy-curable polymers include (meth)acrylate (co)polymers incorporating energy-curable groups. Examples of energy-curable monomers and / or oligomers include esters of polyols and (meth)acrylates. Furthermore, energy-curable adhesives may contain, in addition to energy-curable components, additives such as photopolymerization initiators and crosslinking agents.

[0137] The thickness of the adhesive layer 42 is not particularly limited as long as it functions properly in each step of forming the composite sheet for the protective film. Specifically, the thickness of the adhesive layer is preferably 1~50μm, 2~30μm, 2~20μm, 3~10μm, or 3~8μm.

[0138] The adhesive constituting the adhesive layer 5 for the clamp is preferably an adhesive with the required adhesion and re-peelability, such as acrylic adhesives, rubber adhesives, silicone adhesives, carbamate adhesives, polyester adhesives, and polyvinyl ether adhesives. Among these, acrylic adhesives are preferred because they provide high adhesion to clamps such as the annular frame, effectively preventing the protective film forming composite sheet from peeling off from the annular frame during cutting steps. Alternatively, a substrate serving as a core material may be present midway along the thickness direction of the adhesive layer 5 for the clamp.

[0139] From the viewpoint of the adhesion of clamps such as ring frames, the thickness of the adhesive layer 5 for clamps is preferably 5~200μm, and preferably 10~100μm.

[0140] (4. Method for manufacturing protective film forming film and sheet for protective film forming) There is no particular limitation on the manufacturing method of the protective film forming film. The film can be manufactured using the above-described protective film forming film composition, or a composition obtained by diluting the protective film forming film composition with a solvent (both compositions are referred to as "coating agents"). The coating agent can be prepared by mixing the components constituting the protective film forming film composition using known methods.

[0141] Using a coating machine such as a roller coater, doctor blade coater, roller knife coater, air knife coater, mold coater, bar coater, gravure coater, or curtain coater, the obtained coating agent is applied to the release surface of the first release film, and then dried as needed to form a protective film on the first release film.

[0142] Next, by further attaching the peeling surface of the second peeling film to the exposed surface of the protective film forming film formed on the first peeling film, a protective film forming sheet as shown in FIG4 is obtained.

[0143] (5. Method for manufacturing composite sheets for forming protective films) There are no particular limitations on the manufacturing method of the composite sheet for forming the protective film. For example, it can be manufactured by: separately fabricating a first laminate containing a protective film forming film and a second laminate containing an adhesive sheet as a support sheet, and then using the first laminate and the second laminate, laminating the protective film forming film and the adhesive sheet.

[0144] The first laminate can be manufactured using the same method as the protective film forming sheet described above. That is, a protective film forming film is formed on the peel surface of the first release film, and the peel surface of the second release film is attached to the exposed surface of the protective film forming film.

[0145] On the other hand, to manufacture the second laminate, firstly, an adhesive composition constituting the adhesive layer is prepared, or a composition obtained by diluting the adhesive composition with a solvent (both compositions are referred to as "coating agents"). Next, the coating agent is applied to the release surface of the third release film and dried as needed to form an adhesive layer on the third release film. Then, a substrate is bonded to the exposed surface of the adhesive layer to obtain a laminate (second laminate) consisting of an adhesive sheet and the third release film, wherein the adhesive sheet consists of a substrate and an adhesive layer.

[0146] When the adhesive layer is composed of an energy-curable adhesive, it can be cured by irradiating it with energy rays during this stage, or it can be cured after forming a film-laden layer with the protective film. Furthermore, when curing the adhesive layer after forming a film-laden layer with the protective film, the adhesive layer can be cured before or after the cutting step.

[0147] As energy rays, ultraviolet light and electron beams are commonly used. The amount of energy irradiation varies depending on the type of energy ray. For example, when using ultraviolet light, the preferred intensity is 50–1000 mJ / cm², and the most preferred intensity is 100–500 mJ / cm². Furthermore, when using electron beams, the preferred intensity is approximately 10–1000 krad.

[0148] After obtaining the first laminate and the second laminate in the above manner, the second release film in the first laminate is peeled off, and the third release film in the second laminate is peeled off at the same time. The protective film exposed in the first laminate is then bonded to the adhesive layer of the adhesive sheet exposed in the second laminate.

[0149] This results in a composite sheet for forming a protective film, which comprises an adhesive sheet having an adhesive layer deposited on a substrate, a protective film forming film deposited on the adhesive layer side of the adhesive sheet, and a first release film deposited on the protective film forming film on the opposite side of the adhesive sheet. After peeling off the first release film as needed, a clamping adhesive layer is formed at the periphery of the exposed adhesive layer.

[0150] (6. Manufacturing method of the device) As an example of a manufacturing method for an apparatus for forming a protective film using the present embodiment, a method for obtaining a workpiece with a protective film attached will be described, wherein the workpiece with a protective film attached is obtained by individually processing a workpiece with a protective film attached.

[0151] The manufacturing method of the device in this embodiment includes at least the following steps 1 to 5. Step 1: The step of attaching the protective film to the back of the workpiece; Step 2: Allow the applied protective film to cure, thereby forming a protective film on the back of the workpiece, resulting in a workpiece with a protective film attached; Step 3: Focusing the laser on a pre-defined area inside the workpiece to form the first modified area; Step 4: Focusing the laser on a pre-defined area inside the protective film to form the second modified region; Step 5: Apply tensile force to the workpiece with the protective film formed on the first modified region and the second modified region, thereby monolithically processing the workpiece with the protective film to obtain a plurality of workpieces with protective films.

[0152] Additionally, step 2 is performed before step 4. Furthermore, it is preferable that step 2 is performed before step 3.

[0153] The manufacturing method of the apparatus having steps 1 to 5 described above will be described with reference to the accompanying drawings. Hereinafter, the case where the workpiece is a wafer will be described. First, a protective film is attached to the back side of the workpiece (wafer) (step 1). The attached protective film is not particularly limited, but preferably is, for example, the protective film described above.

[0154] When the protective film forming film is included in the protective film forming sheet, as shown in FIG6A, the protective film forming film 10 of the protective film forming sheet 51 is attached to the back side of the workpiece 6 (step 1). After attachment, the first release film 21 is peeled off as needed.

[0155] Furthermore, when the protective film forming film is included in the protective film forming composite sheet, as shown in FIG6B, the protective film forming film 10 of the protective film forming composite sheet 61 is attached to the wafer 6, which serves as the workpiece (step 1). At this time, the outer periphery of the adhesive layer 42 can be fixed by the annular frame 7. In this embodiment, as shown in FIG5, a clamping adhesive layer 5 is provided on the outer periphery of the adhesive layer 42, therefore, the clamping adhesive layer 5 is attached to the annular frame 7. The protective film forming film 10 is attached to the back side of the wafer 6. The adhesive sheet 4, which serves as a support sheet, can function as a cutting tape for invisible cutting.

[0156] Then, as shown in Figure 7, the attached protective film forming film 10 is cured to form a protective film, resulting in a wafer 100 with the protective film attached (step 2). When the protective film forming film 10 is thermosetting, it is formed by heating the protective film forming film 10 at a specified temperature for an appropriate time. For example, the heating temperature is preferably 100~200°C, and can be any range from 110~180°C to 120~170°C. The heating time is preferably 0.5~5 hours, and can be any range from 0.5~3 hours to 1~2 hours. Furthermore, when the protective film forming film 10 is energy-curable, it is formed by shining energy rays from the side of the adhesive sheet 4 or the release film 21. For example, the illuminance of the energy rays is preferably 120~280mW / cm², and the light intensity of the energy rays is preferably 100~1000mJ / cm².

[0157] A support sheet, which serves as a cutting tape for invisible dicing, is attached to a wafer obtained by curing the protective film forming film 10 of the protective film forming sheet 51 shown in FIG. 4. The support sheet is also attached to the annular frame. As a support sheet, the adhesive sheet described above can be used as an example. That is, when the adhesive sheet is attached to the wafer with the protective film and the annular frame, the fixture adhesive layer 5 can be omitted from the configuration shown in FIG. 7, resulting in a configuration where the adhesive sheet 4 is attached to the annular frame 7.

[0158] Next, as shown in Figure 8, the laser is focused from the laser irradiation device L onto the region inside the wafer 6 corresponding to the predetermined dicing line, thereby forming the first modified region A1 (step 3). Further, before and after forming the first modified region, the laser is focused from the laser irradiation device L onto the region inside the protective film 1 corresponding to the predetermined dicing line, thereby forming the second modified region A2 (step 4).

[0159] The first and second modified regions are areas where the intensity becomes lower than other regions due to laser irradiation, and cracks are generated along the thickness direction of the wafer or protective film in these regions. For example, an infrared laser can be used as the laser.

[0160] The location of the first modified region is not limited as long as the crack extends during propagation and the wafer with the protective film is appropriately divided. Furthermore, multiple first modified regions can also be formed in the depth direction of the wafer.

[0161] By forming a second modified region within the protective film, a portion with lower strength than other parts can be formed in specific areas of the protective film. Therefore, during expansion, the protective film is effectively and fully segmented, starting from the second modified region.

[0162] This state, where a portion of the protective film has lower strength than other parts, corresponds to a right-angle tear test where tensile force tends to concentrate at a specific location on the test piece. Therefore, in this embodiment, by ensuring that the right-angle tear strength of the cured protective film (protective film) in the right-angle tear test is within a specified range, the separability of the workpiece with the protective film attached during expansion can be improved.

[0163] Conversely, a typical tensile test does not correspond to a situation where a specific area of ​​the protective film has a lower strength than other parts. Therefore, the tensile strength calculated based on a typical tensile test is not directly related to the right-angle tear strength.

[0164] In this embodiment, in order to reliably divide the protective film, it is preferable to form the second modified region near the interface between the protective film and the wafer.

[0165] As shown in Figure 9, the wafer 100 with the protective film having the first modified region and the second modified region is individually isolated by extending E (step 5). The isolation of the wafer with the protective film can be carried out by stretching the substrate 41 of the adhesive sheet 4 to apply a tensile force to the wafer with the protective film. The tensile force generates tensile stress inside the wafer 100 with the protective film, causing cracks formed in the first modified region and the second modified region to extend to the two main surfaces of the wafer 100 with the protective film. Finally, the wafer with the protective film is divided into a plurality of small pieces (isolated) along the predetermined dicing line to obtain the wafer 100a with the protective film as a workpiece.

[0166] The expansion can also be a cold expansion performed at a temperature below room temperature (23°C). In this embodiment, even expansion at room temperature can ensure good segmentation of the workpiece with the protective film.

[0167] Furthermore, in this embodiment, by ensuring that the right-angle tear strength of the cured protective film (protective film) in the right-angle tear test is within a specified range, it is possible to suppress accidental splitting of the protective film before expansion due to impacts, etc. As a result, the outer perimeter line of the split protective film is a straight line, which can suppress defects related to the shape of the protective film.

[0168] After expansion, in order to shrink the area that has been stretched and loosened due to expansion, this area of ​​the adhesive sheet can also be subjected to heat treatment (heat shrinkage). Then, as shown in Figure 10, the wafer with the protective film attached is picked up from the adhesive sheet by a vacuum nozzle or the like and recycled.

[0169] The picked-up wafers with protective films can be transported to the next step, or they can be temporarily stored in a tray, belt, etc., and then transported to the next step after a specified period.

[0170] The wafer 100a with a protective film, which will be transported to the next step, is mounted on a substrate to manufacture a semiconductor device.

[0171] (7. Variations) In addition, a peeling film can be deposited on the surface of the protective film forming film 10 side of the composite sheet 61 for forming the protective film to protect the protective film forming film before use.

[0172] The embodiments of the present invention have been described above, but the present invention is not limited to any of the above embodiments and can be modified in various ways within the scope of the present invention. Example

[0173] The present invention will be described in more detail below with reference to embodiments, but the present invention is not limited to these embodiments.

[0174] (Preparation of protective film sheet) A protective film forming sheet is prepared using a coating agent containing the composition for forming a protective film as described below.

[0175] (Coating agent containing a composition for forming a protective film) Mix the following components according to the proportions shown in Table 1 (solid content conversion), and dilute with methyl ethyl ketone to achieve a solid content concentration of 50% by mass, to prepare a coating agent containing a protective film forming composition. (A) Polymer composition (A-1): A (meth)acrylate copolymer composed of 55 parts by mass of n-butyl acrylate, 10 parts by mass of ethyl acrylate, 20 parts by mass of glycidyl methacrylate and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 800,000, glass transition temperature: -31℃). (A-2): A (meth)acrylate copolymer composed of 10 parts by mass of ethyl 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: 400,000, glass transition temperature: 4℃). (B) Curing components (thermosetting components) (B-1) A mixture of liquid bisphenol A type epoxy resin and acrylic rubber microparticles (manufactured by NIPPON SHOKUBAI CO., LTD., BPA328, epoxy equivalent of 235 g / eq) (B-2) Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, JER1055, epoxy equivalent is 800~900g / eq) (B-3) Dicyclopentadiene type epoxy resin (manufactured by DIC CORPORATION, EPICLON HP-7200HH, softening point 88~98℃, epoxy equivalent 274~286g / eq) (C) Curing agent: Dicyandiamide (manufactured by ADEKA CORPORATION, ADEKA HARDENER EH-3636AS, heat-active latent epoxy resin curing agent, active hydrogen content is 21g / eq) (D) Curing accelerator: 2-Phenyl-4,5-dihydroxymethylimidazol (manufactured by SHIKOKU CHEMICALS CORPORATION, CUREZOL 2PHZ-PW) (E) Filler material (E-1) Epoxy-modified spherical silica filler (manufactured by Admatechs, SC2050MA, average particle size 0.5μm) (E-2) Amorphous silica filler (manufactured by TATSUMORI LTD., SV-10, average particle size 8 μm) (F) Coupling agent: epoxy-containing oligomer silane coupling agent (manufactured by Mitsubishi Chemical Corporation, MKC Silicate MSEP2) (G) Colorant: Carbon black (manufactured by Mitsubishi Chemical Corporation, MA-600B, average particle size 20nm)

[0176] A first release film (manufactured by LINTEC Corporation, SP-PET502150) is prepared, formed by forming a silicone-based release agent layer on one side of a 50 μm thick polyethylene terephthalate (PET) film. A second release film (manufactured by LINTEC Corporation, SP-PET381031) is prepared, formed by forming a silicone-based release agent layer on one side of a 38 μm thick polyethylene terephthalate (PET) film.

[0177] The prepared coating agent containing the protective film forming composition was applied to the release treatment surface of the first release film and dried at 100°C for 2 minutes to form a protective film forming film with a thickness of 25 μm. Next, a second release film was attached to the protective film forming film to obtain a three-layer structure protective film forming sheet with release films on both sides of the protective film forming film. The attachment conditions for the second release film were: temperature 60°C, pressure 0.4 MPa, and speed 1 m / min.

[0178] The following measurements and evaluations were performed using the obtained protective film forming sheet.

[0179] (The right-angle tear strength and elongation at break of the cured protective film) The two protective film forming sheets are peeled off, each having its second release film. The exposed surfaces of the protective film forming sheets (the surfaces without the first release film) are then attached to each other. One first release film is peeled off, resulting in a laminate with two protective film forming films deposited on the other first release film. Further, the exposed surface of the protective film forming film from which the second release film has been peeled off from the other protective film forming sheet is attached to the exposed surface of the protective film forming film of the laminate with two protective film forming films deposited on the first release film. The first release film of the other protective film forming sheet is then peeled off. This process is repeated twice, resulting in a total of four protective film forming films being deposited, thus creating a laminate consisting of a first release film, a 100 μm thick protective film forming film, and a first release film, deposited sequentially.

[0180] In addition, when the protective film is 25 μm thick, the thickness of the deposited protective film is preferably 100 μm. When the protective film is not 25 μm thick, the number of layers can be appropriately selected, and the thickness of the deposited protective film is preferably set to 95~120 μm.

[0181] The laminate is heated and cured at 130°C for 2 hours in an atmospheric environment to obtain a laminate with a first release film deposited on both surfaces of the cured protective film.

[0182] Using a super dumbbell cutter (manufactured by DUMBBELL CO., LTD, SDBK-1000), the laminated body with the first release film deposited on both surfaces of the cured protective film is punched according to the dimensions of the right-angle tear test piece described in JIS K 7128-3:1998. The shape of the right-angle tear test piece is as shown in Figure 2 of JIS K 7128-3:1998.

[0183] The first peel film on both surfaces was removed from the obtained right-angle tear test piece, and a right-angle tear test was performed at a test temperature of 23°C using a universal tensile testing machine (manufactured by Shimadzu Corporation, AG-IS). In the right-angle tear test, the test length (clamp spacing) of the right-angle tear test piece before the test was set to 60 mm, the tensile speed was set to 10 mm / min, and the sampling time was set to 10 ms.

[0184] The right-angle tear strength (TS1: N / mm) at 23°C was calculated by dividing the maximum tensile force (N) until the test piece broke by the thickness of the right-angle tear test piece before the test (0.1 mm (=100 μm)). Furthermore, when the elongation of the test piece at fracture is set as ΔL with the start of the tensile test as the reference point, the elongation at fracture at 23°C (%) was calculated using the following formula. The results are shown in Table 1. Elongation at break = (ΔL / test length of the right-angle tear test piece before the test (60mm)) × 100

[0185] (Fabrication of the support sheet) As a support sheet, an adhesive sheet (cutting tape for invisible cutting) having a substrate and an adhesive layer is manufactured in the following manner. In this embodiment, two types of support sheets, support sheet A and support sheet B, are manufactured.

[0186] (Fabrication of support sheet A) The following components (h) and (i) are mixed and diluted with methyl ethyl ketone to a solid content concentration of 25% by mass, thereby preparing a coating agent containing an adhesive layer composition. (h) Adhesive agent: 100 parts by weight of a (meth)acrylate copolymer (weight average molecular weight: 600,000, glass transition temperature: -55℃) obtained by copolymerizing 80 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of methyl methacrylate and 10 parts by weight of 2-hydroxyethyl acrylate. (i) Crosslinking agent: 15 parts by weight of trimethylolpropane phthalimide diisocyanate adduct (manufactured by MITSUI TAKEDA CHEMICALS, INC., TAKENATE D110N).

[0187] As the substrate, a polypropylene film (thickness: 80 μm) with a no-load elongation of 99% in the MD direction and 99% in the CD direction, a tensile modulus of 290 MPa in the MD direction and 270 MPa in the CD direction, and a melting point of 138 °C is prepared.

[0188] The prepared coating agent containing the adhesive layer was applied to a 38 μm thick release film (LINTEC Corporation SP-PET381031) and dried at 100°C for 2 minutes to form a 5 μm thick adhesive layer. Then, the support sheet A was obtained by attaching the adhesive layer to the substrate.

[0189] (Fabrication of support sheet B) The following components (j) to (l) are mixed and diluted with methyl ethyl ketone to a solid content concentration of 25% by mass, thereby preparing a coating agent containing an adhesive layer composition. (j) Adhesive: 100 parts by weight of a (meth)acrylate copolymer (weight average molecular weight: 600,000, glass transition temperature: 6°C) obtained by copolymerizing 22 parts by weight of 2-ethylhexyl acrylate, 73 parts by weight of vinyl acetate, 1 part by weight of acrylic acid and 4 parts by weight of methyl methacrylate. (k) 110 parts by weight of urthane acrylate (manufactured by Dainichiseika Color & Chemicals Mfg.Co.,Ltd., SEIKABEAM14-29B) (l) Crosslinking agent: 5 parts by weight of trimethylolpropane toluene diisocyanate adduct (manufactured by TOSOH CORPORATION, Coronate L).

[0190] As a substrate, a vinyl chloride resin film (manufactured by ACHILLES CORPORATION, PVC80, with a thickness of 80μm) is prepared.

[0191] The prepared coating agent containing the adhesive layer was applied to a 38 μm thick release film (manufactured by LINTEC Corporation, SP-PET381031) and dried at 100°C for 2 minutes to form an adhesive layer with a thickness of 5 μm. Then, the support sheet B was obtained by bonding the adhesive layer to the substrate.

[0192] (Right-angle tear strength of the support sheet) The obtained support sheet was punched into a right-angle tear test piece shape in the same manner as the right-angle tear test of the cured protective film, thus preparing the test piece. No multiple support sheets were stacked on top of each other. The peeling film was removed from the prepared test piece in the same manner as the right-angle tear test of the cured protective film, and the right-angle tear strength (TS2) of the support sheet was measured. The results are shown in Table 1.

[0193] (Extended Experiment) Using an attachment apparatus (LINTEC Corporation, RAD-3600F / 12), the temperature of the workpiece adsorption stage is set to 70°C. The exposed surface, created by peeling off the second release film of the protective film forming sheet (cut to the same shape as the silicon wafer), is attached to a workpiece made of silicon wafers with a thickness of 100 μm and an outer diameter of 8 inches. After peeling off the first release film, the wafer is cured in an oven at 130°C for 2 hours (at atmospheric conditions) to produce a wafer with a protective film attached.

[0194] Then, using an attachment device (manufactured by LINTEC Corporation, RAD-2700F / 12), the aforementioned invisible dicing tape (support sheet A or support sheet B) is attached to the protective film surface of the wafer with the protective film. At this time, dicing tape is also attached to the 8-inch wafer using a ring frame. Using a laser irradiation device (manufactured by DISCO CORPORATION, DFL7361), the laser (wavelength: 1064nm) is focused onto the inside of the wafer and the interface between the protective film and the wafer through the dicing tape. At this time, while scanning along the predetermined dicing lines set in order to form a 5mm × 5mm wafer body, modified regions (first modified region and second modified region) are formed.

[0195] Then, using an expansion device (manufactured by DISCO CORPORATION, DDS2300), at a temperature of 23°C, the dicing tape, which is tightly bonded to the wafer with the protective film, is expanded at a speed of 100 mm / s and under the expansion conditions shown in Table 1.

[0196] Extended tests were conducted on a case where a support sheet without any scratches was used, and on a case where a support sheet with a scratch of 5 mm in length and 10 μm in depth was used in the center of the support sheet, which was intended to prevent scratches from occurring during transportation.

[0197] In the extended test, the case where the protective film and wafer were 100% divided into wafers with the protective film attached was judged as having good slicing performance, and the case where the protective film and wafer were not 100% divided was judged as having unslicing performance. The results are shown in Table 1.

[0198] Furthermore, if the outer perimeter line of the divided protective film is straight, it is considered to have a good outer perimeter shape; if the outer perimeter line of the divided protective film is not straight, the wafer with the protective film is considered to have an unacceptable outer perimeter shape. The results are shown in Table 1.

[0199] In addition, the occurrence of cracking in the support sheet during expansion was evaluated. The results are shown in Table 1.

[0200] [Table 1] Example 1A Example 2A Example 2B Example 2C Example 3A Example 3B Example 3C Comparative Example 1A Comparative Example 1B Comparative Example 1C Comparative Example 2A Comparative Example 3A Protective film forming film ratio polymer components A-1 19 19 - 19.8 19.9 8 A-2 - - 26 - - - Epoxy resin B-1 11.2 11.2 10.4 11.2 11.2 6.2 B-2 2 2 1.7 2 2 1 B-3 5.6 5.6 5.2 5.6 5.6 2.6 curing agent C 0.5 0.5 0.47 0.05 - 0.45 Curing accelerator D 0.4 0.4 0.37 0.05 - 0.45 Filler material E-1 6 6 55.4 6 6 26 E-2 54.8 54.8 - 54.8 54.8 54.8 Coupling agent F 0.4 0.4 0.36 0.4 0.4 0.4 Colorant G 0.1 0.1 0.1 0.1 0.1 0.1 Cured Protective film formation (Protective film) Tear strength (N / mm): TS1 15.28 15.28 19.45 18.65 19.73 8.41 Elongation at break (%) 0.46 0.46 6.59 58.34 61.21 0.39 support plate type Support plate A Support plate B Support plate A Support plate B Support plate A Support plate A Tear strength (N / mm): TS2 169 118 169 118 169 169 Tear strength ratio: TS1 / TS2 0.090 0.129 0.115 0.158 0.117 0.050 Feature Evaluation Expansion 10mm 10mm 15mm 20mm 10mm 15mm 20mm 10mm 15mm 20mm 10mm 10mm Segmentation good good good good good good good Unqualified Unqualified Unqualified Unqualified good Segmented outer perimeter shape good good good good good good good good good good good Unqualified Cracks in the support plate (with scratches) none none none have none none none none none have none none Cracks in the support plate (without scratches) none none none none none none none none none none none none

[0201] As shown in Table 1, when the right-angle tear strength and elongation at break of the cured protective film are within the above-mentioned ranges, the segmentation of the workpiece with the protective film and the outer peripheral shape of the protective film are good during the expansion in stealth cutting. On the other hand, it was also confirmed that when the right-angle tear strength and elongation at break of the cured protective film are outside the above-mentioned ranges, the segmentation or the outer peripheral shape of the protective film is poor.

[0202] 1: Protective film 5: Adhesive layer for clamps 51: Sheet for forming protective film 6: Workpiece 6a: Chip 6b: Convex electrode 10: Protective film formation 10a, 10b: Main face 21: First peeling membrane 22: Second peeling membrane 61: Composite sheet for forming protective film 4: Adhesive sheet 41: Substrate 42: Adhesive layer 7: Circular frame 100: Workpieces with protective film 100a: Chip with protective film 101a: Undivided wafer with protective coating 102a: Wafer with protective film 200: Pre-defined dividing line A1: First Reforming Zone A2: Second Reforming Zone E: Extension L: Laser irradiation device III: Direction

Claims

1. A protective film forming film, which becomes a protective film after curing, wherein, The protective film forming film composition constituting the aforementioned protective film forming film includes a polymer component, a curable component, and a filler material. When the cured protective film forming film is subjected to a right-angle tear test at 23°C, the right-angle tear strength is 10 N / mm or more and 25 N / mm or less, and in the right-angle tear test, the elongation of the cured protective film forming film at the time of breakage is 10% or less.

2. The protective film formed as described in claim 1, wherein, The aforementioned protective film is a thermosetting material or an energy-cured material.

3. A protective film forming film as described in claim 1 or 2, used to form a modified region by focusing a laser onto the aforementioned protective film.

4. A protective film forming sheet having a protective film forming film as described in any one of claims 1 to 3 and a release film disposed on at least one main surface of the aforementioned protective film forming film in a peelable manner.

5. A composite sheet for forming a protective film, comprising a protective film forming film as described in any one of claims 1 to 3 and a support sheet supporting the aforementioned protective film forming film.

6. The composite sheet for forming a protective film as described in claim 5, wherein, When the right-angle tear strength of the protective film formed after curing at 23°C is set as TS1, and the right-angle tear strength of the aforementioned support sheet when a right-angle tear test is performed on the aforementioned support sheet at 23°C is set as TS2, TS1 / TS2 is less than 0.

15.

7. A method for manufacturing an apparatus, comprising: attaching a protective film forming film to the back side of a workpiece; curing the attached protective film forming film to form a protective film on the back side of the workpiece, thereby obtaining a workpiece with a protective film attached; focusing a laser on a predetermined area inside the workpiece to form a first modified area; focusing a laser on a predetermined area inside the protective film to form a second modified area; and applying a tensile force to the workpiece with the protective film having the first modified area and the second modified area formed thereon, thereby single-pieceing the workpiece with the protective film attached, thereby obtaining a plurality of processed workpieces with protective films attached, wherein... The aforementioned protective film forming film is a protective film forming film having a protective film forming sheet, the aforementioned protective film forming sheet having: a protective film forming film that becomes a protective film after curing, and having a right-angle tear strength of 10 N / mm or more when the cured protective film forming film is subjected to a right-angle tear test at 23°C, and an elongation of 10% or less when the cured protective film forming film breaks in the right-angle tear test; and a peeling film disposed on at least one main surface of the aforementioned protective film forming film in a peelable manner; or a protective film forming film having a protective film forming composite sheet, the aforementioned protective film forming composite sheet having: a protective film forming film that becomes a protective film after curing, and having a right-angle tear strength of 10 N / mm or more when the cured protective film forming film is subjected to a right-angle tear test at 23°C, and an elongation of 10% or less when the cured protective film forming film breaks in the right-angle tear test; and a support sheet supporting the aforementioned protective film forming film.

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