Protective sheet

Abstract

Provided is a protective sheet comprising a protective layer for protecting a surface to be protected of a substrate when manufacturing an electronic component device. The protective layer includes a polymer having a glass transition point of 10°C or more and 50°C or less.

Description

protective sheet CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2024-111964, which is incorporated herein by reference.

[0002] The present invention relates to a protective sheet having a protective layer used in the manufacture of electronic component devices such as semiconductor integrated circuits.

[0003] Conventionally, there have been known manufacturing methods for electronic component devices, such as semiconductor integrated circuits. In this type of manufacturing method for electronic component devices, a substrate, such as a silicon wafer, is divided into small pieces to produce a large number of chips. During this process, when the substrate is divided into small pieces, a small portion of the substrate may become tiny pieces, resulting in minute foreign matter. When circuit components, such as circuit wiring or electrodes, are arranged on one side of the substrate, minute foreign matter may adhere to the circuit wiring or electrodes. Furthermore, foreign matter may also adhere to the other side, where circuit components, such as circuit wiring or electrodes, are not arranged. When a large amount of foreign matter adheres to the surface of the substrate, the reliability of the manufactured electronic component device may be reduced, regardless of whether circuit components are arranged on the side with the foreign matter attached.

[0004] In response to this, a surface protection sheet is known that is attached to at least one surface of a substrate and has a protective layer that is removed after protecting the substrate (see, for example, Patent Document 1). The protective layer of the surface protection sheet described in Patent Document 1 contains a polymer such as polyvinyl alcohol and a compound that generates an acid or a base upon irradiation with active energy rays or the like.

[0005] The protective layer of the surface protection sheet described in Patent Document 1 is attached to the surface to be protected, such as a substrate, to protect the surface to be protected when the substrate is processed, and is then removed for use after protecting the surface to be protected. Specifically, the protective layer contains the acid- or base-generating compound, and the acid or base is generated by active energy rays irradiated after processing the substrate, thereby increasing the hydrophilicity of the protective layer. Therefore, the protective layer is removed with water or the like after protecting the surface to be protected.

[0006] WO 2023 / 195445

[0007] However, the protective layer described in Patent Document 1 does not necessarily adhere sufficiently to the substrate or other object to be protected, and the force applied when processing the substrate or other object may cause the protective layer to unintentionally peel off from the surface to be protected. On the other hand, if the hydrophilicity of the polymer is increased, for example, to improve the adhesion of the protective layer, the tackiness (stickiness) of the protective layer at room temperature may increase, which may result in unintentional adhesion of foreign matter to the protective layer or make it difficult to remove a release liner attached to the protective layer. Therefore, it is difficult to achieve both sufficient adhesion of the protective layer and suppression of the tackiness of the protective layer at room temperature.

[0008] Therefore, there is a demand for a protective sheet having a protective layer that has low tackiness at room temperature and can adhere relatively strongly to the surface to be protected, such as a substrate, during processing.

[0009] However, it cannot be said that sufficient research has been conducted on protective sheets that have a protective layer that has low tackiness at room temperature and can adhere relatively strongly to the surface to be protected.

[0010] Therefore, an object of the present invention is to provide a protective sheet having a protective layer that has low tackiness at room temperature and can adhere relatively strongly to the surface to be protected.

[0011] In order to solve the above problems, the protective sheet of the present invention includes a protective layer for protecting a surface of a substrate to be protected when manufacturing an electronic component device, and the protective layer contains a polymer having a glass transition temperature of 10°C or higher and 50°C or lower.

[0012] 1 is a schematic cross-sectional view of an example of a protective sheet according to the present embodiment, cut in the thickness direction; FIG. 2 is a schematic cross-sectional view illustrating an example of a protecting step in the manufacturing method for an electronic component device according to the present embodiment; FIG. 3 is a schematic cross-sectional view illustrating an example of a protecting step in the manufacturing method for an electronic component device according to the present embodiment; FIG. 4 is a schematic cross-sectional view illustrating an example of a step before cleaving a substrate in the manufacturing method for an electronic component device according to the present embodiment; FIG. 5 is a schematic cross-sectional view illustrating an example of a step after cleaving a substrate in the manufacturing method for an electronic component device according to the present embodiment; FIG. 6 is a schematic cross-sectional view illustrating an example of a removing step in the manufacturing method for an electronic component device according to the present embodiment; FIG. 7 is a schematic cross-sectional view illustrating an example of a removing step in the manufacturing method for an electronic component device according to the present embodiment; FIG. 8 is a cross-sectional view of an example of a dicing tape cut in the thickness direction; FIG. 9 is a cross-sectional view of an example of a dicing die bond film cut in the thickness direction; FIG. 10 is a cross-sectional view illustrating a state after a mounting step and a protecting step have been performed in a specific example of a method for manufacturing an electronic component device; FIG. 11 is a cross-sectional view illustrating a state during a blade dicing processing step in a specific example of a method for manufacturing an electronic component device. 1 is a cross-sectional view schematically showing a state after a blade dicing process has been carried out in a specific example of a method for manufacturing an electronic component device. FIG. 2 is a cross-sectional view schematically showing a removal process in a specific example of a method for manufacturing an electronic component device. FIG. 3 is a cross-sectional view schematically showing a pickup process in a specific example of a method for manufacturing an electronic component device. FIG. 4 is a cross-sectional view schematically showing a bonding process in a specific example of a method for manufacturing an electronic component device. FIG. 5 is a cross-sectional view schematically showing a half-cut process of a semiconductor wafer in another specific example of a method for manufacturing an electronic component device. FIG. 6 is a cross-sectional view schematically showing a half-cut process of a semiconductor wafer in another specific example of a method for manufacturing an electronic component device. FIG. 7 is a cross-sectional view schematically showing a mounting process in another specific example of a method for manufacturing an electronic component device.

[0013] Hereinafter, one embodiment of a protective sheet according to the present invention will be described with reference to the drawings.

[0014] As shown in Figure 1, protective sheet 10 includes at least protective layer 11. Protective sheet 10 of this embodiment may further include release liner 15 overlying at least one surface of protective layer 11. Release liner 15 may be overlaid on one or both surfaces of protective layer 11. Note that each figure in the drawings is a schematic view and does not necessarily have the same aspect ratio as the actual product. The same applies to the other drawings.

[0015] In this embodiment, protective layer 11 is formed in a sheet shape. When protective sheet 10 is used, for example, release liner 15 is peeled off from protective layer 11, and protective layer 11 is attached to at least one surface (surface to be protected) of a substrate (object to be protected).

[0016] The protective layer 11 has flexibility that allows it to be deformed by a relatively weak force. The protective layer 11 also has adhesiveness that allows it to adhere to the surface of a substrate to be protected. In other words, the protective layer 11 can be used as a pressure-sensitive sheet adhesive that can be adhered to the surface to be protected by being pressed against the surface to be protected.

[0017] The protective layer 11 of the protective sheet 10 of this embodiment contains a polymer having a glass transition temperature of 10°C or higher and 50°C or lower. The protective layer 11 preferably further contains a compound that generates an acid upon irradiation with active energy rays. The polymer preferably has an ester group (hereinafter also referred to as an easily hydrolyzable ester group) in the molecule that is hydrolyzed by the generated acid to generate a hydrophilic group. In other words, the polymer is preferably a polymer compound that generates a hydrophilic group when the easily hydrolyzable ester group in the molecule is hydrolyzed by the generated acid.

[0018] Examples of hydrophilic groups generated from the easily hydrolyzable ester group (-C(O)O-) by the acid include a carboxy group (-COOH) and a hydroxy group (-OH). In other words, a carboxy group or a hydroxy group can be generated from the easily hydrolyzable ester group.

[0019] The polymer preferably contains, in the molecule, a structural unit of a (meth)acrylic acid ester monomer that generates a carboxyl group as a hydrophilic group in response to the acid.

[0020] The proportion of the total mass of the above-described polymer and the above-described acid-generating compound to the total mass of the protective layer 11 is preferably 98 mass % or more, and more preferably 99 mass % or more. Preferably, the protective layer 11 does not contain a compound having an isocyanate group in the molecule.

[0021] When the protective layer 11 is bonded to a silicon wafer at 23°C, it preferably has an adhesive strength of 0.5 N / 10 mm or less, more preferably 0.2 N / 10 mm or less, and even more preferably 0.1 N / 10 mm or less. A smaller adhesive strength can reduce the tackiness of the protective layer 11 at room temperature. This can further inhibit foreign matter from adhering to the protective layer 11, and can make it easier to peel off a release liner attached to the protective layer 11. This can improve the handleability (ease of handling) of the protective layer 11 at room temperature. The adhesive strength may be 0.01 N / 10 mm or more.

[0022] The adhesive strength can be reduced by, for example, increasing the glass transition temperature of the polymer contained in the protective layer 11. On the other hand, the adhesive strength can be increased by, for example, decreasing the glass transition temperature of the polymer contained in the protective layer 11.

[0023] When bonded to a silicon wafer at 70° C., the protective layer 11 preferably has an adhesive strength of 1.0 N / 10 mm or more, more preferably 3.0 N / 10 mm or more, and even more preferably 5.0 N / 10 mm or more. A higher adhesive strength can further enhance the adhesion of the protective layer 11 to the surface to be protected. The adhesive strength may be 15.0 N / 10 mm or less, or 10.0 N / 10 mm or less.

[0024] The adhesive strength (adhesive strength after lamination at 70°C) can be adjusted, for example, by changing the molecular weight of the polymer contained in the protective layer 11. The adhesive strength can also be adjusted, for example, by changing the type or composition ratio of the monomers used to synthesize the polymer. Specifically, the glass transition temperature of the polymer can be lowered by appropriately increasing the proportion of the monomer that lowers the glass transition temperature, thereby increasing the adhesive strength. On the other hand, the glass transition temperature of the polymer can be increased by decreasing the proportion of the monomer that lowers the glass transition temperature, thereby decreasing the adhesive strength.

[0025] The protective layer 11 was irradiated with active energy rays at 1 J / cm from a high-pressure mercury lamp. ２ After being irradiated with active energy rays, the protective layer 11 preferably has an adhesive strength of 1.0 N / 10 mm or less to a silicon wafer, more preferably an adhesive strength of 0.5 N / 10 mm or less, and even more preferably an adhesive strength of 0.1 N / 10 mm or less. The smaller adhesive strength after being irradiated with active energy rays allows the protective layer 11 to be more easily removed after protecting the surface of the adherend to be protected. The protective layer 11 can be removed, for example, by peeling it off, or by using a liquid containing water.

[0026] The adhesive strength (adhesive strength after irradiation) can be reduced by, for example, increasing the content of the polymer (having an easily hydrolyzable ester group in the molecule) contained in the protective layer 11. On the other hand, the adhesive strength can be increased by, for example, decreasing the content of the polymer (having an easily hydrolyzable ester group in the molecule) contained in the protective layer 11.

[0027] The above-mentioned adhesive strength measurements are all carried out as follows. A backing tape (ultraviolet-transmitting type) is attached to the protective layer, and then cut to prepare a 10 mm wide test sample. The protective layer of the prepared test sample is attached to a bare silicon wafer at 23°C or 70°C. Using a tensile tester, one longitudinal end of the sheet-like test sample is held with a chuck, and a 180-degree peel test (peel test) is carried out at room temperature (23°C) by peeling the test sample at a speed of 300 mm / min. The adhesive strength after irradiation with active energy rays is measured by attaching the test sample to a bare silicon wafer at 70°C, and then irradiating the test sample with ultraviolet light (1 J / cm) from the backing tape side. ２ ) and then measured in the same manner as above.

[0028] The protective layer 11 of this embodiment is used, for example, to protect the surface to be protected of a substrate that constitutes an electronic component device.

[0029] By overlapping the protective layer 11 on the surface to be protected, the protective layer 11 can be tightly adhered to the surface of the substrate to be protected (the surface to be protected) until the protective layer is removed. This prevents foreign matter from adhering to the surface to be protected. For example, even when the substrate and protective layer 11 are processed into small pieces while the protective layer 11 and the substrate are overlapped, the above-mentioned adhesion strength prevents the protective layer 11 from peeling off from the substrate during the small pieces. Furthermore, foreign matter such as debris that may be generated during the processing can be prevented from adhering to the surface to be protected, thereby protecting the surface to be protected.

[0030] In this embodiment, the compound that generates an acid is, for example, an acid generator that generates an acid upon irradiation with active energy rays. The compound that generates an acid is preferably a photoacid generator that generates an acid upon irradiation with active energy rays (particularly ultraviolet rays).

[0031] As described above, the polymer has, for example, an ester group (easily hydrolyzable ester group) in the molecule that is hydrolyzed by the generated acid. Examples of hydrophilic groups generated by the acid include a carboxy group (-COOH) and a hydroxy group (-OH). The carboxy group or hydroxy group can be generated from the easily hydrolyzable ester group.

[0032] When the protective layer 11 contains the above-mentioned acid-generating compound, the protective layer 11 is irradiated with active energy rays, whereby an acid is generated from the above-mentioned acid-generating compound. As a result, the above-mentioned easily hydrolyzable ester groups in the polymer molecules are hydrolyzed, increasing the number of hydrophilic groups in the polymer and significantly increasing the hydrophilicity of the protective layer 11. The protective layer 11, whose hydrophilicity has been significantly increased, can be relatively easily peeled off from the surface to be protected by contact with a liquid containing water. Therefore, the protective layer 11 is easily detached from the surface to be protected. In this way, when the protective layer 11 contains the above-mentioned acid-generating compound and the polymer containing the above-mentioned easily hydrolyzable ester groups, not only can it adhere sufficiently to the surface to be protected of the substrate, which is a component of the electronic component device to be manufactured, but it can also be relatively easily removed from the surface to be protected by a liquid containing water after irradiation with active energy rays.

[0033] When the protective layer 11 contains the above-mentioned acid-generating compound, it has a physical property that increases its hydrophilicity by irradiation with active energy rays such as ultraviolet rays. The protective layer 11 only needs to have a predetermined level of hydrophilicity or higher after the ester groups of the polymer are hydrolyzed. Therefore, before the ester groups of the polymer are hydrolyzed, the hydrophilicity of the protective layer 11 may be less than the predetermined level or may be greater than the predetermined level. When the protective layer 11 has a hydrophilicity greater than the predetermined level, at least a portion of the protective layer 11 can dissolve in a liquid containing water.

[0034] The above polymer has a glass transition point of 10°C or higher and 50°C or lower before being irradiated with active energy rays, as described above. Therefore, the protective layer 11 has low tackiness at room temperature and can adhere relatively strongly to the surface to be protected. The glass transition point of the above polymer is preferably 30°C or lower. When the glass transition point is higher than 10°C, the tackiness of the protective layer 11 at room temperature can be further reduced. On the other hand, when the glass transition point is lower than 50°C, there is an advantage that the protective layer 11 can adhere relatively strongly to the surface to be protected without necessarily having to be heated when bonding the protective layer 11 to the surface to be protected.

[0035] The glass transition temperature of the polymer can be appropriately adjusted by, for example, changing the type or molecular structure of the raw material monomer used to synthesize the polymer. When a commercially available product is used as the polymer, a polymer having a desired glass transition temperature can be obtained and used.

[0036] The above polymer was subjected to irradiation with active energy rays (1 J / cm from a high-pressure mercury lamp). ２ After being subjected to irradiation with light, the protective layer 11 preferably has a glass transition point of 30° C. or higher and 150° C. or lower. Such a higher glass transition point can improve the removability of the protective layer 11 with water or the like.

[0037] The glass transition point is measured as follows. Specifically, differential scanning calorimetry (DSC) is performed on the protective layer, and the glass transition point (Tg) is determined from the measurement chart. When determining the glass transition point (Tg) from the measurement chart, the "midpoint glass transition temperature (Tmg)" described in JIS K7121 (1987) "Method for measuring transition temperatures of plastics" is used as the glass transition point (Tg). <Measurement conditions> Measurement temperature: -60°C to 100°C Measurement sample amount: 5 to 10 mg is weighed out The glass transition point of the polymer after irradiation with active energy rays described above is a measured value measured after carrying out irradiation treatment under the following conditions: Active energy ray irradiation treatment: 1 J / cm using a high-pressure mercury lamp ２ Irradiation of

[0038] From another viewpoint, the polymer is preferably a polymer compound having a hydrophilic group (e.g., a carboxyl group) in the molecule that is protected by a protecting group but can be deprotected by the acid. The protecting group is present in the polymer in a state chemically bonded to the hydrophilic group.

[0039] Examples of protecting groups capable of protecting the above-mentioned hydrophilic groups include the following protecting groups. Examples of protecting groups capable of protecting a carboxy group include a tert-butyl group, an alkoxyalkyl group, or a cyclic acetal group (a group containing a dioxolane structure). Examples of alkoxyalkyl groups include a methoxymethyl group, an ethoxyethyl group, or a butoxyethyl group. In an alkoxyalkyl group, the number of consecutively bonded carbon atoms may be 2 or more and 4 or less. Examples of protecting groups capable of protecting a hydroxy group include a trityl group, an alkoxymethyl group, a tetrahydropyranyl group, a cyclic acetal group (a group containing a dioxolane structure), a tert-butyldimethylsilyl group, or a tert-butoxycarbonyl group.

[0040] It should be noted that the above notation of the protecting group does not necessarily directly represent the state in which the hydrophilic group and the protecting group are bonded. For example, when the hydrophilic group is a carboxy group and the protecting group is a tert-butyl group, an ester bond is formed by the reaction of the carboxy group with tert-butyl alcohol, but even in such a case, the protecting group is described as a tert-butyl group. Furthermore, protected hydrophilic groups are also described by their names before protection.

[0041] When the easily hydrolyzable ester group in the polymer is hydrolyzed by the acid, a new hydrophilic group is generated in the polymer. In other words, when the protecting group is removed from the hydrophilic group (deprotection), the protecting group portion is removed from the hydrophilic group portion. The compound separated from the polymer by hydrolysis, i.e., the compound derived from the protecting group, may or may not be volatile.

[0042] The above polymer may have an ester group (easily hydrolyzable ester group) of a constituent unit of a (meth)acrylic acid ester type monomer in the molecule. In other words, the above polymer may be a polymer (hereinafter simply referred to as an acrylic polymer) in which at least a (meth)acrylic acid ester type monomer containing an easily hydrolyzable ester group is polymerized. In this specification, the term "(meth)acrylic acid" includes both acrylic acid and methacrylic acid. The same applies to "(meth)acrylate."

[0043] The acrylic polymer has, for example, a main chain and multiple side chains in the molecule. The main chain is a covalently bonded chain formed, for example, by a radical polymerization reaction. At least a portion of the main chain is preferably a covalently bonded chain formed by the polymerization reaction of a (meth)acrylic acid ester monomer containing an easily hydrolyzable ester group. The side chain has, for example, an easily hydrolyzable ester group in a state in which a carboxy group as a hydrophilic group is dehydrated and condensed. From another perspective, in the side chain of the acrylic polymer, the carboxy group as a hydrophilic group formed by the above-mentioned acid is protected by a protecting group to become an easily hydrolyzable ester group.

[0044] The acrylic polymer may be a homopolymer of a (meth)acrylic acid ester type monomer containing an easily hydrolyzable ester group, or a copolymer of a (meth)acrylic acid ester type monomer containing an easily hydrolyzable ester group and a monomer other than the above monomer. The average molecular weight of the acrylic polymer may be 50,000 or more and 900,000 or less.

[0045] Examples of the structural unit of the (meth)acrylic acid ester type monomer (containing an easily hydrolyzable ester group) contained in the molecule of the acrylic polymer include structural units of the following monomers: tert-butyl (meth)acrylate [(meth)acrylic acid t-butyl ester] Alkoxyalkyl (meth)acrylate [(meth)acrylic acid alkoxyalkyl ester] (represented by the following general formula (I))

[0046] Specific examples of the alkoxyalkyl (meth)acrylate represented by the general formula (I) include n-propoxyethyl acrylate [(meth)acrylic acid propoxyethyl ester], n-butoxyethyl (meth)acrylate [(meth)acrylic acid 1-butoxyethyl ester], and cyclohexoxyethyl acrylate [(meth)acrylic acid cycloalkoxyethyl ester].

[0047] When the acrylic polymer contains easily hydrolyzable ester groups in its molecules, the hydrophilicity of the protective layer containing the acrylic polymer is low. Therefore, even when the protective layer comes into contact with a solvent containing water, it is not removed from the surface to be protected and continues to protect the surface. Furthermore, since the polymer molecules contain a large number of polar ester groups, the protective layer can adhere relatively strongly to the object to be protected. On the other hand, after the protective layer 11 is irradiated with active energy rays, the easily hydrolyzable ester groups are hydrolyzed by the acid generated by the irradiation to generate carboxyl groups and the like. In other words, the protected carboxyl groups and the like are deprotected. Therefore, the hydrophilicity of the protective layer 11 is increased, and the protective layer 11 can be removed relatively easily from the surface to be protected using a liquid containing water.

[0048] The (meth)acrylic acid ester monomer structural unit contains an easily hydrolyzable ester group and generates an acrylic acid monomer structural unit or a methacrylic acid monomer structural unit after hydrolysis. In other words, the (meth)acrylic acid ester monomer structural unit has a molecular structure in which the carboxy group in each acrylic acid monomer or methacrylic acid monomer structural unit is protected by a protecting group.

[0049] The acrylic polymer preferably contains 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more of the structural units (containing easily hydrolyzable ester groups) of the (meth)acrylic acid ester monomer in the molecule. The acrylic polymer may contain 95% by mass or more of the structural units (containing easily hydrolyzable ester groups) of the (meth)acrylic acid ester monomer. By including a larger amount of the structural units of the (meth)acrylic acid ester monomer in the acrylic polymer, the protective layer 11 can adhere more strongly to the surface to be protected. Meanwhile, when the protective layer 11 is subjected to an active energy ray irradiation treatment in the removal step (described in detail later), the acid generated from the photoacid generator or the like hydrolyzes the easily hydrolyzable ester groups, generating many new carboxyl groups. Therefore, the protective layer 11 can be more easily removed by a liquid containing water.

[0050] Examples of monomers copolymerizable with the above (meth)acrylic acid ester type monomers include vinyl acetate (vinyl acetate), alkyl (meth)acrylates [(meth)acrylic acid alkyl esters], hydroxyalkyl (meth)acrylates [(meth)acrylic acid hydroxyalkyl esters], carboxyalkyl (meth)acrylates [(meth)acrylic acid carboxyalkyl esters], (meth)acrylic acid, N-(hydroxyalkyl)(meth)acrylamide, (meth)acrylates having a polyethylene glycol chain, etc. In other words, the above acrylic polymers may have, in addition to the structural units of the above (meth)acrylic acid ester type monomers, the structural units of the monomers listed above in the molecule.

[0051] The acrylic polymer is preferably an acrylic copolymer having, at least in the molecule, a structural unit of a (meth)acrylic acid ester type monomer (containing an easily hydrolyzable ester group) and at least one structural unit of a hydroxyalkyl (meth)acrylate or an N-(hydroxyalkyl)(meth)acrylamide.

[0052] In this embodiment, the acid-generating compound is a compound that newly generates an acid when irradiated with active energy rays. The active energy ray irradiation treatment will be described in detail later.

[0053] An example of the acid-generating compound is a photoacid generator. When the acid-generating compound generates an acid upon irradiation with light, at least a portion of the easily hydrolyzable ester groups in the polymer contained in the protective layer 11 is hydrolyzed, resulting in the appearance of hydrophilic groups such as carboxyl groups. This increases the hydrophilicity of the protective layer 11. Therefore, the protective layer 11 can be easily removed from the surface to be protected by contacting the protective layer 11 with a liquid containing water.

[0054] The photoacid generator used as the acid generator is, for example, a photocationic polymerization initiator that is generally used for cationic polymerization. As the photoacid generator, commercially available products can be used.

[0055] Photoacid generators include ionic and nonionic types. Ionic photoacid generators have a cationic structure and an anionic structure. Examples of ionic photoacid generators, depending on the type of cationic structure, include onium salt compounds, sulfonimide compounds, and disulfonyldiazomethane compounds.

[0056] Examples of the onium salt compound include onium salt compounds such as iodonium salt compounds, sulfonium salt compounds, oxime sulfonate compounds, and diazonium salt compounds. Among these, iodonium salt compounds and sulfonium salt compounds are preferred, and sulfonium salt compounds are more preferred, in that they generate an acid with stronger acidity (stronger acid) and can generate hydrophilic groups from polar groups of the polymer even in a small amount used.

[0057] Examples of iodonium salt compounds include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, bis(4-tert-butylphenyl)iodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, diphenyliodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium camphorsulfonate, bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, bis(4-fluorophenyl)iodonium triflate, diphenyliodonium hexafluorophosphate, etc. Other examples include the iodonium salt compounds used in the following examples.

[0058] Examples of sulfonium salt compounds include diphenyl[4-(phenylsulfanyl)phenyl]sulfonium=trifluorotris(pentafluoroethyl)-λ ５-phosphanide, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoro-normal butanesulfonate, triphenylsulfonium camphorsulfonate, 4,7-di-n-butoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium adamantanecarboxylate trifluoroethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium methanesulfonate, triphenylsulfonium phenolsulfonate, triphenylsulfonium nitrate, triphenylsulfonium maleate, bis(triphenylsulfonium)maleate, triphenylsulfonium hydrochloride (triphenylsulfonium chloride), triphenylsulfonium acetate, triphenylsulfonium trifluoroacetate, triphenylsulfonium salicylate, triphenylsulfonium benzoate, triphenylsulfonium hydroxide, and the like. Other examples include the sulfonium salt compounds used in the following examples (for example, "CPI-310FG" manufactured by San-Apro Co., Ltd.).

[0059] Examples of the oxime sulfonate compound include (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (5-octylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (camphorsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, (5-p-toluenesulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile, and (5-octylsulfonyloxyimino)-(4-methoxyphenyl)acetonitrile.

[0060] The diazonium salt compound may, for example, be 4-nitrobenzenediazonium tetrafluoroborate.

[0061] Examples of commercially available onium salt compounds include OPTOMER SP-150, OPTOMER SP-170, and OPTOMER SP-171 (all manufactured by ADEKA Corporation), UVE-1014 (manufactured by General Electronics Corporation), OMNICAT250 and OMNICAT270 (both manufactured by IGM Resin), IRGACURE290 (manufactured by BASF Corporation), SAN-AID SI-60L, SAN-AID SI-80L, and SAN-AID SI-100L (all manufactured by Sanshin Chemical Industry Co., Ltd.), CPI-100B, CPI-100P, CPI-101A, and CPI-200K (all manufactured by San-Apro Ltd.).

[0062] Examples of the sulfonimide compound as a photoacid generator include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoro-normal-butanesulfonyloxy)succinimide, N-(camphorsulfonyloxy)succinimide, N-(trifluoromethanesulfonyloxy)naphthalimide, N-(camphorsulfonyloxy)succinimide, N-(4-methylphenylsulfonyloxy)succinimide, N-(2-trifluoromethylphenylsulfonyloxy)succinimide, N-(4-fluorophenylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(camphorsulfonyloxy)phthalimide, N-(2-trifluoromethylphenylsulfonyloxy)phthalimide, N-(2-fluorophenylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(camphorsulfonyloxy)diphenylmaleimide, and 4-methylphenylsulfonyloxy)diphenylmaleimide.

[0063] Examples of disulfonyldiazomethane compounds as photoacid generators include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(2,4-dimethylbenzenesulfonyl)diazomethane, and methylsulfonyl-p-toluenesulfonyldiazomethane.

[0064] Other examples of photoacid generators include 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-triazine.

[0065] The photoacid generator preferably has good compatibility with the above polymer, and is preferably an ionic photoacid generator.

[0066] In the protective layer 11, the amount of the acid-generating compound relative to 100 parts by mass of the polymer is preferably 0.2 parts by mass or more, and more preferably 1.0 part by mass or more. This allows the protective layer 11 to have higher hydrophilicity after irradiation with active energy rays, and therefore makes the protective layer 11 more easily removable by a liquid containing water. The amount of the acid-generating compound relative to 100 parts by mass of the polymer is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less. This more sufficiently prevents the acid-generating compound from remaining in the protective layer 11.

[0067] In addition to the above-described components, the protective layer 11 of this embodiment may further contain, for example, a solvent, a surfactant, etc. Examples of the solvent include water or an organic solvent. As the organic solvent, a relatively volatile organic solvent is preferable. Examples of such organic solvents include ethanol and methanol.

[0068] The protective layer 11 of this embodiment preferably does not contain either a photopolymerization initiator or a thermal polymerization initiator. If the protective layer of this embodiment contains a photopolymerization initiator or a thermal polymerization initiator, the easily hydrolyzable ester groups in the polymer may chemically react with the photopolymerization initiator or the thermal polymerization initiator. If a reaction occurs, the hydrophilic groups that would be generated after hydrolysis may not be generated. Therefore, the protective layer may not retain its hydrophilicity even after being irradiated with active energy rays. Therefore, it may be difficult to remove the protective layer using a liquid containing water.

[0069] The protective layer 11 of this embodiment may be produced by evaporating the solvent from a protective layer-forming composition obtained by mixing the above-mentioned polymer, an acid-generating compound such as the above-mentioned photoacid generator, and, if necessary, a solvent, etc., using a conventional method.

[0070] The protective layer 11 may be formed, for example, by applying the above-mentioned solvent-containing composition for forming a protective layer to the surface to be protected of the adherend and then volatilizing the solvent. Alternatively, the protective layer 11 may be formed by applying the above-mentioned solvent-containing composition for forming a protective layer to one surface of the release liner 15 and then volatilizing the solvent. The formed protective layer 11 preferably does not contain a solvent blended to impart fluidity to the above-mentioned composition for forming a protective layer. Note that the protective layer 11 may be formed, for example, from the above-mentioned solvent-free composition for forming a protective layer by a general molding method.

[0071] In the protective sheet, the thickness of the protective layer 11 is not particularly limited, but is, for example, 1 μm or more and 100 μm or less. This thickness may be 3 μm or more. Furthermore, this thickness may be 40 μm or less, 30 μm or less, or even 30 μm or less. When the protective layer 11 is a laminate, the above thickness is the total thickness of the laminate.

[0072] The protective layer 11 may have physical properties that allow it to be stretched in the planar direction before being irradiated with active energy rays and thereby be broken into small pieces. The protective layer 11 having such physical properties is preferably used when manufacturing electronic component devices through a DBG process. Similarly, it is preferably used when manufacturing electronic component devices through a stealth processing step using a stealth dicing device. Note that the protective layer 11 may also be preferably used when manufacturing electronic component devices through a blade dicing processing step, and therefore does not need to have such physical properties.

[0073] The protective sheet 10 of this embodiment is used, for example, during the process of manufacturing an electronic component device. Specifically, the protective sheet 10 of this embodiment is used for purposes such as temporarily protecting the surface to be protected (the surface to be protected) of an electronic component (a type of substrate). More specifically, the protective layer 11 of the protective sheet 10 of this embodiment is attached to the surface to be protected of the electronic component (a type of substrate). Examples of the electronic component include substrates such as semiconductor wafers, semiconductor chips, and wired circuit boards, as well as connected wired circuit boards formed by connecting multiple wired circuit boards, and pseudo wafers.

[0074] The semiconductor chip typically includes a semiconductor chip body and electrode portions disposed on one or both sides of the semiconductor chip body and electrically connected to electrode portions of another component. Examples of such other components include a wiring circuit board or another semiconductor chip. The semiconductor chip may have a circuit surface on at least one side. Specifically, the semiconductor chip may be a TSV (Through Silicon Via) type semiconductor chip having paired electrode portions disposed on both sides of the semiconductor chip body and a conductive portion penetrating the semiconductor chip body in the thickness direction to electrically connect the electrode portions. A TSV type semiconductor chip may have a circuit surface formed on only one side, or may have a circuit surface formed on both sides. The circuit of the semiconductor chip may also include a sensor element (e.g., a light-receiving element or a vibration element) as an element. An example of such a semiconductor chip is a sensor chip. Examples of sensor chips include a CMOS (Complementary Metal-Oxide Semiconductor) chip and a MEMS (Micro Electron Systems) chip.

[0075] The pseudo wafer includes, for example, a support substrate and a package body in which a plurality of semiconductor chips arranged on the support substrate are collectively sealed with resin. The pseudo wafer may be the package body removed from the support substrate. A rewiring layer may be formed on at least a portion of the surface of the pseudo wafer. The protective sheet 10 may be used to cover the rewiring layer. Note that the divided bodies obtained by dividing the pseudo wafer into constituent units each including at least one semiconductor chip may be electronic components.

[0076] As described above, there are various types of electronic components that have surfaces to be protected, and various electronic components can serve as the substrate.

[0077] Next, an embodiment of a method for manufacturing an electronic component device will be described.

[0078] The method for manufacturing the electronic component device includes a step of protecting at least one of the surfaces to be protected of both surfaces of a substrate by overlaying a protective layer 11 on the surface to be protected (protection step), and a step of removing the protective layer 11 overlaid on the surface to be protected (removal step), wherein the protective layer 11 includes a compound that generates an acid when irradiated with active energy rays, and the above-mentioned polymer having an ester group in the molecule that is hydrolyzed by the acid to generate a hydrophilic group, and in the removal step, the acid is generated from the compound that generates an acid when irradiated with active energy rays, and the ester group (easily hydrolyzable ester group) is hydrolyzed to increase the hydrophilicity of the protective layer 11, and the protective layer 11 is removed by contacting the protective layer 11 with a liquid containing water.

[0079] In the protection step, as shown in Figure 2A, the surface to be protected of the substrate S may be protected using a protective sheet 10 having a release liner 15 on one side of a protective layer 11. For example, after the protective layer 11 of the protective sheet 10 is superimposed on the surface to be protected of the substrate S, the release liner 15 may be peeled off from the protective layer 11 (see Figure 2B).

[0080] 2C and 2D , the method for manufacturing an electronic component device of this embodiment may further include a step of dividing the stacked laminate of substrates S and protective layers 11 into small pieces at intervals in the surface direction, thereby producing a plurality of stacked small pieces of chips S′ formed by dividing the substrates into small pieces and small pieces 11′ formed by dividing the protective layers into small pieces. Note that, before being divided, the substrate S may have weakened portions or the like formed inside for dividing into small pieces.

[0081] In the removal step, as shown in FIG. 2E, the protective layer fragments 11' are irradiated with active energy rays such as ultraviolet light to generate new acids from the acid-generating compounds contained in each of the fragments 11', and the newly generated acids hydrolyze the easily hydrolyzable ester groups, thereby increasing the hydrophilicity of each of the fragments 11'. In the removal step, as shown in FIG. 2F, each of the protective layer fragments 11' overlapping the circuit surface of the chip S' is removed using a liquid containing water. The manufacturing method for an electronic component device according to this embodiment may further include a step of placing the circuit surface of the chip S' facing the adherend and bonding the chip S' to the adherend.

[0082] The electronic component device manufactured by the manufacturing method of this embodiment includes at least one of the various electronic components described above. Examples of the electronic component device include a semiconductor device such as a semiconductor integrated circuit including a semiconductor chip, a device including a system LSI having a complementary metal oxide semiconductor (CMOS), or a device including a microelectromechanical system (MEMS) in which mechanical elements, sensors, actuators, or electronic circuits are integrated on a single silicon substrate, glass substrate, or organic material substrate using microfabrication technology. The manufactured electronic component device may also include a device including a wiring circuit board.

[0083] In the method for manufacturing an electronic component device according to this embodiment, at least one surface of the substrate is protected by a protective layer. The surface to be protected (hereinafter simply referred to as the surface to be protected) may be either one surface or both surfaces of the substrate. Circuit components (described in detail below) may or may not be disposed on the surface to be protected.

[0084] The substrate may be made of any material, as long as it is plate-shaped. Examples of the substrate material include glass, silicon, stainless steel (SUS), plastic, and ceramic. Examples of the substrate include a semiconductor wafer, a sensor wafer such as a CMOS or MEMS, a pseudo wafer, and a wiring circuit board.

[0085] In the above-mentioned protection step, a protective layer 11 may be overlaid on the surface of the substrate on which at least one of the circuit wiring, sensor unit, and electrode unit is arranged as a circuit component. For example, the protective layer 11 may be overlaid on one side (circuit surface) of the substrate on which the circuit wiring is arranged, the protective layer 11 may be overlaid on one side of the substrate on which the sensor unit is arranged, or the protective layer 11 may be overlaid on one side of the substrate on which the electrode unit is arranged. In the above-mentioned protection step, it is preferable to overlay the protective layer 11 on at least one side of the substrate so as to cover the circuit wiring, sensor unit, or electrode unit with the protective layer 11. Examples of circuit components include circuit wiring, electrode units, or elements such as transistors, diodes, or sensor units (such as light-receiving sensors or vibration sensors).

[0086] The following will describe in detail the case where a semiconductor integrated circuit (semiconductor device) is manufactured as an electronic component device.

[0087] Generally, a method for manufacturing a semiconductor device includes a front-end process in which a circuit surface is formed on one side of a wafer using highly integrated electronic circuits, and a back-end process in which chips are cut out from the wafer with the circuit surface formed and assembled.

[0088] In a post-process, for example, a fragile portion is formed on the wafer (semiconductor wafer) as a substrate on which a circuit surface is formed, for dicing into small semiconductor chips (dies), and an adhesive fixing layer of dicing tape is attached to the surface opposite the circuit surface. Then, while the semiconductor wafer is attached to the adhesive fixing layer of the dicing tape, the dicing tape is stretched in the planar direction, dicing the semiconductor wafer into semiconductor chips along the fragile portion. The diced semiconductor chips are then peeled off from the adhesive fixing layer of the dicing tape.

[0089] The above-mentioned post-processing includes, for example, a stealth processing step in which fragile portions for dicing the wafer into small chips (dies) are formed in the wafer using laser light or the like, a mounting step in which the surface of the semiconductor wafer opposite the circuit surface is attached to a dicing tape to fix the semiconductor wafer, an expanding step in which the semiconductor wafer is diced into semiconductor chips (dies) by stretching the dicing tape in the surface direction, a pick-up step in which the semiconductor chips are peeled off from the adhesive fixing layer and removed, and a bonding step in which the removed semiconductor chips are bonded to an adherend. A semiconductor integrated circuit (semiconductor device) is manufactured through, for example, these steps.

[0090] In the manufacturing method of a semiconductor device (electronic component device) of this embodiment, for example, semiconductor chips are cut out from a semiconductor wafer on which a circuit surface is formed, and a semiconductor device having the cut-out semiconductor chips is assembled. In the manufacturing method of a semiconductor device of this embodiment, a semiconductor device is manufactured as follows using at least the protective layer 11 of the protective sheet 10 and a dicing tape 20 (see FIG. 3A). These sheets and tapes are used as auxiliary tools for manufacturing a semiconductor device. It is also possible to use a dicing die bond film in which a die bond sheet 30 is superimposed on the adhesive fixing layer 22 of the dicing tape 20 (see FIG. 3B). Commercially available products can be used as the dicing tape 20 and the dicing die bond film.

[0091] A specific example of the method for manufacturing a semiconductor device will be described in detail below.

[0092] The method for manufacturing a semiconductor device of this example includes an assembly step of cutting out semiconductor chips X from a semiconductor wafer W (substrate) on which a circuit surface is formed, and assembling a semiconductor device having such semiconductor chips X. The assembly process includes the steps of: protecting the circuit surface (surface to be protected) by overlaying a protective layer 11 for protecting the circuit components on at least one surface of the semiconductor wafer W, which is a circuit surface on which any of the circuit components is formed; dividing the laminate of the overlapping semiconductor wafer W and the protective layer 11 into small pieces at intervals in the surface direction to produce a plurality of small pieces of a laminate in which the semiconductor wafer W is divided into small pieces and the small pieces 11' of the protective layer are overlapped; irradiating each of the small pieces 11' of the protective layer overlaying the circuit surface of the semiconductor chip X with active energy rays to generate an acid from the acid-producing compound in each of the small pieces 11', hydrolyzing the easily hydrolyzable ester groups with the acid, thereby increasing the number of hydrophilic groups in the molecules of the polymer and increasing the hydrophilicity of each of the small pieces 11', and then removing each of the small pieces 11' of the protective layer with a liquid containing water; and bonding the semiconductor chip X to an adherend.

[0093] The assembly process of this example includes, for example, the following steps. Specifically, the assembly process of this example includes: a mounting process in which a semiconductor wafer W having circuit components formed on one side thereof is attached to a dicing die bond film (a die bond sheet 30 superimposed on a dicing tape 20) and the semiconductor wafer W is fixed to the dicing die bond film; a protection process in which a protective layer 11 is attached to the circuit side of the semiconductor wafer W to protect the circuit side; a blade dicing process (a process for producing a plurality of small pieces of the laminate described above) in which the semiconductor wafer W to which the die bond sheet 30 and the protective layer 11 are attached is diced with a dicing blade T or the like to produce semiconductor chips (dies) obtained by dicing the semiconductor wafer W; a removal process (the removing process described above) in which a plurality of small pieces 11' of the protective layer attached to the semiconductor chip X are removed after the above-mentioned active energy ray irradiation treatment; and a pick-up process in which the small pieces 30' of the die bond sheet are peeled off from the dicing tape 20 to take out the semiconductor chip X with the small pieces 30' of the die bond sheet attached. and a bonding step (the above-mentioned bonding step) of bonding the extracted semiconductor chip X to an adherend via the die-bonding sheet piece 30'. When these steps are carried out, the above-mentioned protective layer 11 and the dicing die-bonding film having the dicing tape 20 are used as manufacturing aids.

[0094] The semiconductor wafer W is configured to obtain a plurality of semiconductor chips X. Specifically, the semiconductor wafer W is configured to be divided into small pieces at intervals in a plurality of directions along the surface (for example, directions along the surface that are perpendicular to each other), so that a plurality of semiconductor chips X can be fabricated. Furthermore, the semiconductor wafer W has a circuit surface on at least one surface on which at least one type of circuit component is arranged. For example, the semiconductor wafer W used in this example has a circuit surface formed on one of its surfaces.

[0095] In recent years, with the further advancement of integration technology in the semiconductor industry, thinner semiconductor chips (e.g., thicknesses of 20 μm to 50 μm) are desired. When viewed from one side in the thickness direction, the semiconductor chip has, for example, a rectangular shape, with a side length of, for example, 5 mm to 20 mm.

[0096] In the mounting step, as shown in FIG. 4A, a dicing ring R is attached to the adhesive fixing layer 22 of the dicing tape 20, and a semiconductor wafer W is attached and fixed to a die bond sheet 30 superimposed on the dicing tape 20.

[0097] In the protection step, as shown in FIG. 4A , for example, a protective layer 11 is superimposed on one of the circuit surfaces of the semiconductor wafer W. In the protection step, for example, the protective layer 11 may be superimposed on the circuit surface by directly pressing and adhering the protective layer 11 to the circuit surface. Alternatively, a protective layer-forming composition containing solid components constituting the protective layer 11 and a solvent that dissolves the solid components may be prepared, and the prepared protective layer-forming composition may be applied to the circuit surface, followed by volatilizing the solvent to form the protective layer 11 in contact with the circuit surface, thereby superimposing the protective layer 11 on the circuit surface. Typically, the protective layer 11 is superimposed on the circuit surface while heating at a temperature higher than room temperature. By superimposing the protective layer 11 on the circuit surface of the semiconductor wafer W, the circuit surface can be protected by the protective layer 11 until it is removed. Therefore, the adhesion of dust and the like to the circuit surface of the semiconductor wafer W covered with the protective layer 11 can be prevented. The protection step may be performed after the mounting step, or the mounting step may be performed after the protection step.

[0098] In the blade dicing process, the semiconductor wafer W is diced, as shown in FIGS. 4B and 4C . Specifically, the semiconductor wafer W is cut to a predetermined size together with the die bond sheet 30 to form semiconductor chips with the die bond sheet 30. The blade dicing process is performed using, for example, a dicing blade T according to a conventional method. For example, a cutting method called a full cut, in which the cut is made up to the die bond sheet 30, can be employed in the blade dicing process. The dicing device used in the blade dicing process is not particularly limited, and any conventionally known device can be used. In the blade dicing process, foreign matter such as debris may be generated when the semiconductor wafer W is cut. Since the surface of the semiconductor wafer W to be protected is protected by the protective layer 11, adhesion of foreign matter to the surface to be protected can be suppressed. Prior to the blade dicing process, a dicing ring R may be attached to the adhesive fixing layer 22 of the dicing tape 20, and then the dicing ring R may be fixed to the holder H of the expanding device.

[0099] In the removal step, as shown in FIG. 4D, the plurality of small pieces 11′ of the protective layer are subjected to a treatment to generate an acid from the acid-generating compound. For this treatment, an active energy ray irradiation treatment is adopted. In the active energy ray irradiation treatment, for example, 10 mW / cm ２ More than 300mW / cm ２ The ultraviolet rays with the following intensity are used as active energy rays, and the cumulative light amount is 50 mJ / cm ２ More than 5000mJ / cm ２ The plurality of small pieces 11' of the protective layer are irradiated with ultraviolet light as follows: In the removal process, by performing the above-described treatment on the plurality of small pieces 11' of the protective layer, an acid is generated from the acid-generating compound contained in the small pieces 11'. The newly generated acid hydrolyzes the easily hydrolyzable ester groups in the polymer contained in the small pieces 11' of the protective layer, thereby generating new hydrophilic groups such as carboxyl groups. This increases the hydrophilicity of the small pieces 11' of the protective layer. As a result, when the small pieces 11' are later brought into contact with a liquid containing water, at least a portion of the small pieces 11' is dissolved, and the small pieces 11' are relatively easily removed from the surface of the semiconductor chip X.

[0100] In the removal step, as shown in FIG. 4E , the protective layer fragments 11′ are brought into contact with a liquid containing water, and the liquid dissolves at least a portion of each of the fragments 11′, thereby removing each of the protective layer fragments 11′ from the surface (surface to be protected) of the semiconductor chip X. By removing the protective layer fragments 11′ in this manner, all of the protective layer fragments 11′ can be removed relatively easily, and the liquid can also relatively easily reduce the number of foreign substances attached to the semiconductor chip surface. Furthermore, the surface (surface to be protected) of each semiconductor chip X on which the protective layer fragments 11′ overlap can also be cleaned with the liquid.

[0101] In the removal step, at least a portion of the fragmented protective layer (the plurality of small pieces 11' of the protective layer) is dissolved by the liquid. As a result, the adhesive strength of the small pieces 11' of the protective layer to the semiconductor chip X weakens, and the small pieces 11' of the protective layer become more easily peeled off from the semiconductor chip X. This allows the plurality of small pieces 11' of the protective layer to be removed relatively easily.

[0102] The water-containing liquid is not particularly limited as long as it is a liquid substance containing water. Such a liquid may contain 30% by mass or more of water, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more of water. The liquid may contain a component that dissolves in water in addition to water. Examples of such a component include water-soluble organic solvents. Examples of such water-soluble organic solvents include monohydric alcohols having 4 or less carbon atoms, such as methanol, ethanol, propanols such as isopropyl alcohol, and butanols such as tert-butanol.

[0103] In the removal step of this specific example, the protective layer pieces 11' may be immersed in the stirred liquid to bring the liquid into contact with the protective layer pieces 11'. Alternatively, the liquid may be sprayed from a nozzle or the like to bring the protective layer pieces 11' into contact with the liquid. The temperature of the liquid is not particularly limited and may be set to, for example, 10°C or higher and 90°C or lower.

[0104] For example, in the removal step, the liquid is sprayed toward the semiconductor chips X attached to the die bond sheet pieces 30' while rotating a disk-shaped stage supporting the dicing tape 20 from below in the circumferential direction. This makes it possible to remove the multiple protective layer pieces 11' overlapping the semiconductor chips X. The rotation speed of the stage may be, for example, 500 rpm or more and 4000 rpm or less, the amount of liquid sprayed may be, for example, 0.05 L / min or more and 5.0 L / min or less, and the spraying time may be, for example, 5 seconds or more and 300 seconds or less.

[0105] According to this specific example of the semiconductor device manufacturing method, the protective layer 11 is superimposed on the surface (circuit surface) of the semiconductor wafer W on which the circuit components are formed, thereby protecting the circuit surface until the protective layer 11 is removed. Specifically, the semiconductor wafer W is diced into small pieces while the semiconductor wafer W and the protective layer 11 are superimposed to produce the semiconductor chips X. This prevents foreign matter, such as debris that may be generated when the semiconductor wafer W is cleaved, from adhering to the circuit surface of the semiconductor chips X. Even if foreign matter is adhering to the circuit surface of the semiconductor chips X before the protective layer 11 is superimposed, the foreign matter can be removed when the small pieces 11' of the protective layer superimposed on the circuit surface of the semiconductor chips X are removed. Therefore, the adhesion of foreign matter to the circuit surface of the semiconductor chips X to be manufactured can be suppressed. Furthermore, even if water comes into contact with the protective layer 11 while the protective layer 11 is protecting the circuit surface, the protective layer 11 is not removed by a liquid containing water because the protective layer 11 has low hydrophilicity before being irradiated with active energy rays.

[0106] 4F, in the pick-up process, the semiconductor chip X is peeled off from the adhesive fixing layer 22 of the dicing tape 20. More specifically, the pin members P are raised to push up the semiconductor chip X to be picked up through the dicing tape 20. The pushed-up semiconductor chip X is held by the suction jig J.

[0107] During the pickup process, the die bond sheet pieces 30' attached to the semiconductor chips X must be easily peeled from the adhesive fixing layer 22 of the dicing tape 20. Furthermore, during the expanding process, the dicing tape 20 must be stretched to effectively separate the die bond sheet 30, the semiconductor wafer W, and the protective layer 11 into small pieces, as needed. The dicing tape 20 described above is designed to effectively achieve this performance. For example, the dicing tape 20 is configured so that the adhesive fixing layer 22 hardens and the adhesive strength of the adhesive fixing layer 22 decreases when irradiated with active energy rays (e.g., ultraviolet rays). The hardening of the adhesive fixing layer 22 after irradiation reduces the adhesive strength of the adhesive fixing layer 22, allowing the semiconductor chips X and the die bond sheet pieces 30' to be relatively easily peeled from the adhesive fixing layer 22 after irradiation. Dicing tapes 20 configured in this manner are commercially available.

[0108] In the bonding process, the semiconductor chip X with the die bond sheet piece 30' attached thereto is bonded to the adherend Z. In other words, the semiconductor chip X is bonded to the adherend Z via the die bond sheet piece 30'. Note that, in the bonding process, as shown in FIG. 4G, the semiconductor chips X with the die bond sheet piece 30' attached thereto may be stacked multiple times. In this specific example, the semiconductor chip X is bonded to the adherend, such as a substrate or semiconductor chip X, via the die bond sheet piece 30'. When stacking multiple semiconductor chips X as described above in the bonding process, the stacked semiconductor chips X are prevented from having foreign matter attached to their circuit surfaces, thereby reducing the number of foreign matter that gets between one stacked semiconductor chip X and the other stacked semiconductor chip X. Note that examples of the adherend Z include an interposer, a wired circuit board, or a small piece of a substrate (when small pieces of a substrate are stacked and laminated).

[0109] In this example, in order to protect the semiconductor chip X after the bonding step, a resin sealing step may be carried out in which the semiconductor chip X is sealed (covered) with a thermosetting resin or the like.

[0110] In the above description of this specific example, an example was given in which the semiconductor wafer W was diced into small pieces by a blade dicing process. However, the semiconductor wafer W may also be diced into small pieces through a so-called DBG process, in which the thickness of the semiconductor wafer W is reduced after half-cutting the semiconductor wafer W. In the half-cutting process, for example, grooves are formed in the semiconductor wafer W to process the semiconductor wafer W into chips (dies) by a cleaving process, and the semiconductor wafer W is then ground to reduce its thickness. In the half-cutting process, as shown in FIGS. 4H to 4K, for example, a wafer processing tape E is applied to the surface of the semiconductor wafer W opposite the circuit surface. With the wafer processing tape E applied, a dividing groove is formed. A backgrinding tape B is applied to the surface with the grooves formed, while the initially applied wafer processing tape E is peeled off. With the backgrinding tape B applied, the semiconductor wafer W is ground until it reaches a predetermined thickness. Then, a mounting process is performed, and then a semiconductor device is manufactured in the same manner as described above.

[0111] The semiconductor wafer W (substrate) before being diced into semiconductor chips X may be ground to a desired thickness by back-grinding, for example. Specifically, in the back-grinding, the semiconductor wafer W having a back-grinding tape B attached to its circuit surface may be ground to reduce the thickness of the semiconductor wafer W to the thickness of the semiconductor chips X to be fabricated later.

[0112] Processes other than those shown in the above specific examples may also be performed. For example, in processes such as plasma dicing and stealth dicing, the protective layer 11 may be superimposed on the circuit surface of the semiconductor wafer W, and after various processing steps are performed, the protective layer 11 may be removed. Alternatively, with the protective layer 11 disposed between the backgrinding tape B and the semiconductor wafer W as described above, the grinding process may be performed as described above, and then the mounting process may be performed.

[0113] Although the protective sheet according to the embodiment of the present invention is as exemplified above, the present invention is not limited to the above example. In other words, various forms used in general protective sheets can be employed as long as they do not impair the effects of the present invention.

[0114] For example, as described above, the semiconductor wafer used in the manufacturing method of the present invention may be a semiconductor wafer having circuit surfaces formed on both sides, or, as described in other embodiments, a semiconductor wafer having a circuit surface formed on only one side. In other words, the semiconductor chip produced by the manufacturing method described above may have circuit components arranged on only one of its two sides, or may have circuit components arranged on both sides.

[0115] The present specification discloses the following: (1) A protective sheet comprising a protective layer for protecting a surface of a substrate to be protected when manufacturing an electronic component device, the protective layer comprising a polymer having a glass transition point of 10°C or higher and 50°C or lower. A protective sheet having the above configuration can provide a protective layer that has low tackiness at room temperature and can adhere relatively strongly to the surface to be protected. (2) The protective sheet according to (1) above, wherein the protective layer has an adhesive strength of 0.5 N / 10 mm or less when attached to a silicon wafer at 23°C. (3) The protective sheet according to (1) or (2) above, wherein the protective layer has an adhesive strength of 1.0 N / 10 mm or more when attached to a silicon wafer at 70°C. (4) The protective layer, when attached to a silicon wafer at 70°C, is irradiated with active energy rays of 1 J / cm from a high-pressure mercury lamp. ２(5) The protective sheet according to any one of (1) to (3), wherein the protective layer further comprises a compound that generates an acid when irradiated with active energy rays, and the polymer has, in its molecule, an ester group that is hydrolyzed by the acid to generate a hydrophilic group. (6) The protective sheet according to (5), wherein the polymer has, in its molecule, a structural unit of a (meth)acrylic acid ester monomer that generates a carboxyl group as the hydrophilic group when irradiated with the acid.

[0116] The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these examples.

[0117] Each protective layer was prepared in the examples and comparative examples, and protective sheets each having a protective layer were manufactured as follows. Details of each protective layer in each manufacturing method and the evaluation results are shown in Table 1.

[0118] <Monomer raw materials> Details of the monomers used for polymerizing are as follows: [BEA] n-butoxyethyl acrylate (see formula (A) below, purchased product) [PEA] n-propoxyethyl acrylate (see formula (B) below, purchased product) [CHEA] Cyclohexoxyethyl acrylate (see formula (C) below, purchased product) [BEMA] n-butoxyethyl methacrylate (see formula (D) below, purchased product) <Other monomers> ・[4HBA] 4-hydroxybutyl acrylate (purchased product) ・[HEAA] N-(2-hydroxyethyl)acrylamide (purchased product)

[0119] [Examples 1 and 2, Comparative Examples 1 and 2] (Preparation of Polymer) Acrylic polymers were prepared according to the compositions shown in Table 1. Specifically, the monomers shown in Table 1, a polymerization initiator (azobisisobutyronitrile AIBN), and a reaction solvent (ethyl acetate) were mixed together so that the solid content was approximately 25% by mass. A solution polymerization reaction was carried out at a temperature of 65°C to 70°C to synthesize the acrylic polymers.

[0120] (Preparation of Protective Sheets) An acid-generating compound (photoacid generator) was added to and mixed with each of the polymer solutions containing the acrylic polymers prepared as described above in the amounts shown in Table 1 relative to the polymer solids (except for Comparative Example 2). Each acrylic polymer solution was applied to release liner a (PET film, 50 μm thick). Each release liner a had a surface treated with silicone release, and the polymer solution was applied to this surface using an applicator. This was then dried at 130°C for 2 minutes to form a 5 μm-thick protective layer on one side of release liner a. Release liner b (PET film, 38 μm thick) was then superimposed on the exposed surface of each protective layer. Each release liner b had a surface treated with silicone release, and this surface was attached to the protective layer. In this manner, protective sheets comprising a protective layer sandwiched between two release liners were prepared.

[0121] Details of the acid-generating compound (photoacid generator) are as follows. All of the following raw materials were used in the form of a 50% by mass solution in an organic solvent. - Sulfonium salt type Product name "CPI-310FG" manufactured by San-Apro Co., Ltd. Solid content 100% by mass (used after preparing a 50% by mass MEK solution) - Sulfonium salt type Product name "CPI-410B" manufactured by San-Apro Co., Ltd. 50% by mass solution in propylene carbonate Chemical name: (9-Oxo-9H-thioxanthen-2-yl)[4-[(9-oxo-9H-thioxanthen-2-yl)thio]phenyl](phenyl)sulfonium - Sulfonium salt type Product name "CPI-200K" manufactured by San-Apro Co., Ltd. 50% by mass solution in propylene carbonate Chemical name: diphenyl[4-(phenylsulfanyl)phenyl]sulfonium=trifluorotris(pentafluoroethyl)-λ ５ -Phosphanoid [Synonym: Diphenyl[4-(phenylthio)phenyl]sulfonium, trifluorotris(1,1,2,2,2-pentafluoroethyl)phosphate(1-) (1:1)]

[0122]

[0123] <Physical Properties: Glass Transition Point (Tg) of Acrylic Polymer (Before UV Irradiation Treatment)> The glass transition point (Tg) of each acrylic polymer was measured by differential scanning calorimetry (DSC) according to the method for measuring glass transition point described above. The measurement results of the glass transition point (Tg) are shown in Table 1.

[0124] <Evaluation: Tackiness of Protective Layer at Room Temperature (Before UV Irradiation Treatment)> The adhesive strength of each protective layer to a silicon wafer was measured as follows to evaluate the tackiness of the protective layer at room temperature. First, a backing tape was attached to each protective layer, and the protective layer was then cut to prepare a 10 mm wide test sample. The protective layer of the prepared test sample was attached to a bare silicon wafer at 23°C. Using a tensile tester, one longitudinal end of the sheet-like test sample was gripped with a chuck, and a 180-degree peel test (peel test) was performed at room temperature (23°C) by peeling the test sample at a rate of 300 mm / min.

[0125] <Evaluation: Adhesion of Protective Layer (Before and After UV Irradiation Treatment)> The adhesive strength of each protective layer to the silicon wafer was measured as follows, and the adhesive strength of the protective layer to the silicon wafer was evaluated. Specifically, a 180-degree peel test was carried out in the same manner as the above-mentioned tackiness evaluation method, except that the protective layer of the prepared test sample was attached to a bare silicon wafer at 70°C. In addition, the adhesive strength after irradiation with active energy rays was evaluated by attaching the test sample to a bare silicon wafer at 70°C and irradiating the test sample with UV light (1 J / cm) from the backing tape side. ２ ) and then measured in the same manner as above.

[0126] <Evaluation: Removability (Water Solubility) of Protective Layer (After UV Irradiation)> Each protective layer was attached to a bare silicon wafer with a diameter of 6 inches at 70°C, and the bare silicon wafer was then attached to a dicing tape. The test sample thus prepared was attached to a dicing ring. The protective layer was exposed to a high-pressure mercury lamp at 0.5 or 1.0 [J / cm ２] irradiation treatment (light irradiation treatment including ultraviolet light) was performed to enhance the hydrophilicity of the protective layer. Thereafter, to remove the protective layer, a cleaning unit (product name DFD6361) manufactured by DISCO Corporation was used to spray water at 25°C toward the bare silicon wafer while rotating a disk-shaped stage supporting the dicing tape from below in the circumferential direction. The stage rotation speed was 1500 rpm, and the water spraying time was 180 seconds. Whether the protective layer had been peeled and removed from the substrate (bare silicon wafer) was evaluated. The following evaluation criteria were followed: (Excellent) ○ The protective layer was completely removed. (Good) △ Most of the protective layer was removed, but some remained (remaining was confirmed in 10% or less of the total area). (Poor) × The protective layer was not removed at all, or most of it remained (remaining was confirmed in more than 10% of the total area).

[0127] As can be seen from the above evaluation results, the protective layers of each Example had low tackiness at room temperature. Furthermore, the protective layers of each Example were able to adhere relatively strongly to the surface of the silicon wafer to be protected. Furthermore, after irradiating the fragmented protective layers with active energy rays (such as ultraviolet rays), the fragmented protective layers could be removed relatively easily with water.

[0128] By carrying out the method for manufacturing a semiconductor device according to the embodiment as described above, it is possible to efficiently manufacture a semiconductor device in which a plurality of semiconductor chips are stacked together, with almost no foreign matter adhering thereto.

[0129] The method for manufacturing an electronic component device of the present invention is suitably used for manufacturing a semiconductor device having, for example, a semiconductor integrated circuit.

[0130] 10: Protective sheet, 11: Protective layer, 11': Small piece of protective layer, 15: Release liner, 20: Dicing tape, 21: Base layer, 22: Adhesive fixing layer, 30: Die bond sheet, G: Glass carrier, W: Semiconductor wafer, X: Semiconductor chip, V: Through via, D: Electrode portion, B: Backgrinding tape.

Claims

1. A protective sheet comprising a protective layer for protecting a surface of a substrate to be protected when manufacturing an electronic component device, the protective layer comprising a polymer having a glass transition temperature of 10°C or higher and 50°C or lower.

2. The protective sheet according to claim 1, wherein the protective layer has an adhesive strength of 0.5 N / 10 mm or less when laminated to a silicon wafer at 23°C.

3. The protective sheet according to claim 1 or 2, wherein the protective layer has an adhesive strength of 1.0 N / 10 mm or more when attached to a silicon wafer at 70°C.

4. When the protective layer is bonded to a silicon wafer at 70°C, it is irradiated with active energy rays at 1 J / cm from a high-pressure mercury lamp. ２ 3. The protective sheet according to claim 1, which has an adhesive strength of 1.0 N / 10 mm or less to a silicon wafer after being exposed to irradiation.

5. The protective sheet according to claim 1 or 2, wherein the protective layer further contains a compound that generates an acid when irradiated with active energy rays, and the polymer has an ester group in the molecule that is hydrolyzed by the acid to generate a hydrophilic group.

6. The protective sheet according to claim 5, wherein the polymer has, in its molecule, structural units of (meth)acrylic acid ester monomers that generate carboxyl groups as the hydrophilic groups in response to the acid.

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