Protective sheet

Abstract

To provide a protective sheet having a protective layer which has low tackiness at room temperature and can relatively strongly adhere to a surface to be protected.SOLUTION: The protective sheet includes a protective layer for protecting a protection target surface of a substrate when an electronic component device is manufactured, and the protective layer contains a polymer having a glass transition point of 10 °C or more and 50 °C or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] 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. [Background technology]

[0002] Conventionally, there have been known methods for manufacturing electronic component devices, such as semiconductor integrated circuits, in which a substrate, such as a silicon wafer, is divided into small pieces to produce a large number of chips. During such processing, when the substrate is divided into small pieces, a small portion of the substrate may become tiny pieces, resulting in minute foreign matter. If circuit components such as circuit wiring or electrode portions are arranged on one side of the substrate, minute foreign matter may adhere to the circuit wiring or electrode portions. Furthermore, foreign matter may also adhere to the other side, on which circuit components such as circuit wiring or electrode portions are not arranged. If a large amount of foreign matter adheres to the surface of the substrate, the reliability of the manufactured electronic component device as a product may be reduced, regardless of whether circuit components are arranged on the side to which the foreign matter adheres.

[0003] 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 (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 when irradiated with active energy rays or the like.

[0004] 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 and used 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, after protecting the surface to be protected, the protective layer is removed with water or the like. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2023 / 195445 Summary of the Invention [Problem to be solved by the invention]

[0006] 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 in order to improve the adhesion of the protective layer, for example, the tackiness (stickiness) of the protective layer at room temperature may increase, which may cause foreign matter to unintentionally adhere 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.

[0007] 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.

[0008] 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.

[0009] 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. [Means for solving the problem]

[0010] In order to solve the above problems, the protective sheet of the present invention comprises: a protective layer for protecting the surface of the substrate to be protected when manufacturing the electronic component device; The protective layer contains a polymer having a glass transition temperature of 10°C or higher and 50°C or lower. [Effects of the Invention]

[0011] The protective sheet of the present invention can provide a protective layer that has low tackiness at room temperature and can adhere relatively strongly to the surface to be protected. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view of an example of a protective sheet according to an embodiment of the present invention, cut in the thickness direction. [Figure 2A] 5A and 5B are schematic cross-sectional views illustrating an example of a protection step in the method for manufacturing an electronic component device according to the present embodiment. [Figure 2B] 5A and 5B are schematic cross-sectional views illustrating an example of a protection step in the method for manufacturing an electronic component device according to the present embodiment. [Figure 2C] FIG. 3 is a schematic cross-sectional view showing an example of a state before a substrate is cut in the manufacturing method of an electronic component device according to the present embodiment. [Figure 2D] 5 is a schematic cross-sectional view showing an example of a state after the substrate is cut in the manufacturing method of the electronic component device according to the embodiment. FIG. [Figure 2E] 5A and 5B are schematic cross-sectional views illustrating an example of a removing step in the method for manufacturing an electronic component device according to the present embodiment. [Figure 2F] 5A and 5B are schematic cross-sectional views illustrating an example of a removing step in the method for manufacturing an electronic component device according to the present embodiment. [Figure 3A] FIG. 2 is a cross-sectional view of an example of a dicing tape cut in the thickness direction. [Figure 3B] FIG. 2 is a cross-sectional view of an example of a dicing die bond film cut in the thickness direction. [Figure 4A] FIG. 10 is a cross-sectional view schematically illustrating a state after a mounting step and a protection step are performed in a specific example of a method for manufacturing an electronic component device. [Figure 4B] 10A and 10B are cross-sectional views schematically illustrating a state during a blade dicing process in a specific example of a method for manufacturing an electronic component device. [Figure 4C] FIG. 10 is a cross-sectional view schematically illustrating a state after a blade dicing process is performed in a specific example of a method for manufacturing an electronic component device. [Figure 4D] 10A to 10C are cross-sectional views schematically illustrating a removal step in a specific example of a method for manufacturing an electronic component device. [Figure 4E] 10A to 10C are cross-sectional views schematically illustrating a removal step in a specific example of a method for manufacturing an electronic component device. [Figure 4F] 10A and 10B are cross-sectional views schematically illustrating a pickup step in a specific example of a method for manufacturing an electronic component device. [Figure 4G] 5A to 5C are cross-sectional views schematically illustrating a bonding step in a specific example of a method for manufacturing an electronic component device. [Figure 4H] 10A and 10B are cross-sectional views schematically illustrating a state of half-cut processing of a semiconductor wafer in another specific example of the method for manufacturing an electronic component device. [Figure 4I] 10A and 10B are cross-sectional views schematically illustrating a state of half-cut processing of a semiconductor wafer in another specific example of the method for manufacturing an electronic component device. [Figure 4J] 10A and 10B are cross-sectional views schematically illustrating a state of half-cut processing of a semiconductor wafer in another specific example of the method for manufacturing an electronic component device. [Figure 4K] 10A to 10C are cross-sectional views schematically illustrating a mounting step in another specific example of the method for manufacturing an electronic component device. DETAILED DESCRIPTION OF THE INVENTION

[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 that overlays at least one surface of protective layer 11. Release liner 15 may be overlaid on one or both surfaces of protective layer 11. It should be noted that the figures in the drawings are schematic diagrams and do 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 with a relatively small 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 above 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-mentioned polymer and the above-mentioned 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 is preferable that the protective layer 11 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. The smaller adhesive strength can reduce the tackiness of protective layer 11 at room temperature, thereby making it possible to more effectively prevent foreign matter from adhering to protective layer 11 and more easily remove a release liner attached to protective layer 11. This can improve the handleability (ease of handling) of 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 the protective layer 11 is bonded to a silicon wafer at 70° C., it 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 larger adhesive strength can further increase 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, by appropriately increasing the proportion of the monomer that lowers the glass transition point, the glass transition point of the polymer can be lowered, and the adhesive strength can be increased. On the other hand, by decreasing the proportion of the monomer that lowers the glass transition point, the glass transition point of the polymer can be raised, and the adhesive strength can be reduced.

[0025] The protective layer 11 was irradiated with active energy rays at 1 J / cm 2 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. Since the adhesive strength is smaller after being irradiated with active energy rays, the protective layer 11 can 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 easily hydrolyzable ester groups 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 easily hydrolyzable ester groups in the molecule) contained in the protective layer 11.

[0027] The above adhesive strength measurements are all carried out as follows. A backing tape (UV-transmitting type) is applied to the protective layer, which is then cut to prepare a 10 mm wide test sample. The protective layer of the prepared test sample is then bonded 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 gripped with a chuck, and a 180-degree peel test (peel test) is performed 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 was measured by bonding a test sample to a bare silicon wafer at 70°C, and then irradiating the backing tape with ultraviolet light (1 J / cm 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 processing is performed to break the substrate and protective layer 11 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 cutting into small pieces. Furthermore, foreign matter such as fragments that may be generated during 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 acid generated. 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. This hydrolyzes the easily hydrolyzable ester groups in the polymer molecules, 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 above-mentioned polymer containing an easily hydrolyzable ester group, it can not only adhere sufficiently to the surface to be protected of the substrate, which is a component of the electronic component device being manufactured, but 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 its hydrophilicity increases upon 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 higher than the predetermined level. When the protective layer 11 has a hydrophilicity or higher 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 temperature 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 temperature 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 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 needing to be heated when being attached 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 polymers were subjected to irradiation with active energy rays (1 J / cm from a high-pressure mercury lamp). 2 After being subjected to irradiation, 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℃ to 100℃ Measurement sample amount: Weigh out 5 to 10 mg The glass transition temperature of the polymer after irradiation with active energy rays is a value measured after irradiation under the following conditions. Active energy ray irradiation treatment: 1J / 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 the protecting groups capable of protecting the above hydrophilic groups include the following protecting groups. Examples of protecting groups that can protect 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 the alkoxyalkyl group, the number of consecutively bonded carbon atoms may be 2 or more and 4 or less. Examples of protecting groups that can protect 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, and a tert-butoxycarbonyl group.

[0040] Note that the notation of the protecting group above 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. Even in such a case, the protecting group is described as a tert-butyl group. Furthermore, the protected hydrophilic group is also described by its name 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 polymer may have an ester group (easily hydrolyzable ester group) of a constituent unit of a (meth)acrylic acid ester monomer in the molecule. In other words, the polymer may be a polymer (hereinafter simply referred to as an acrylic polymer) obtained by polymerizing at least a (meth)acrylic acid ester monomer containing an easily hydrolyzable ester group. In this specification, the term "(meth)acrylic acid" encompasses 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, for example, a covalently bonded chain formed by a radical polymerization reaction. Preferably, at least a portion of the main chain is a covalently bonded chain formed by the polymerization reaction of a (meth)acrylic acid ester type 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 viewpoint, in the side chain of the acrylic polymer, the carboxy group as a hydrophilic group generated 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 constituent units of the (meth)acrylic acid ester type monomer (containing an easily hydrolyzable ester group) contained in the molecule of the acrylic polymer include the constituent 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)) [ka]

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

[0047] When the acrylic polymer contains easily hydrolyzable ester groups in its molecule, the protective layer containing the acrylic polymer has low hydrophilicity. 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 to be protected. Moreover, since the polymer molecule contains a large number of ester groups, which are polar 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. That is, 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 relatively easily removed from the surface to be protected by a liquid containing water.

[0048] The structural unit of the (meth)acrylic acid ester monomer contains an easily hydrolyzable ester group and generates a structural unit of an acrylic acid monomer or a structural unit of a methacrylic acid monomer after hydrolysis. In other words, the structural unit of the (meth)acrylic acid ester monomer has a molecular structure in which the carboxy group in each structural unit of the acrylic acid monomer or the methacrylic acid monomer 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 type 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 type monomer. The acrylic polymer contains a larger amount of the (meth)acrylic acid ester monomer structural unit, which allows the protective layer 11 to adhere more firmly to the surface to be protected. Meanwhile, when the protective layer 11 is irradiated with active energy rays in the removal step (described in detail below), 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 (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, and (meth)acrylates having polyethylene glycol chains. In other words, the acrylic polymers may have, in addition to the structural units of the (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 irradiation treatment with active energy rays 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 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 acids with stronger acidity (stronger acids) and can generate hydrophilic groups from polar groups of the polymer even in small amounts.

[0057] Examples of iodonium salt compounds include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, bis(4-tert-butylphenyl)iodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoronormal butanesulfonate, diphenyliodonium perfluoronormal 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-n-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] Examples of the diazonium salt compound include 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), OMNICAT 250 and OMNICAT 270 (both manufactured by IGMResin), IRGACURE 290 (manufactured by BASF), 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 Co., Ltd.).

[0062] Examples of sulfonimide compounds as photoacid generators include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoronormalbutanesulfonyloxy)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, which allows the protective layer 11 to have higher hydrophilicity after being irradiated 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, which can more sufficiently prevent the acid-generating compound from remaining in the protective layer 11.

[0067] In addition to the above-mentioned components, the protective layer 11 of this embodiment may further contain, for example, a solvent, a surfactant, etc. Examples of the solvent include water and an organic solvent. The organic solvent is preferably a relatively volatile organic solvent, such as ethanol or 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 group in the polymer may chemically react with the photopolymerization initiator or the thermal polymerization initiator. If this reaction occurs, the hydrophilic group 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 the solvent blended to impart fluidity to the above-mentioned composition for forming a protective layer. The protective layer 11 may be formed, for example, from the above-mentioned composition for forming a protective layer that does not contain a solvent by a general molding method.

[0071] In the protective sheet, the thickness of protective layer 11 is not particularly limited, but is, for example, 1 μm or more and 100 μm or less. Such a thickness may be 3 μm or more. Also, such a thickness may be 40 μm or less, or 30 μm or less, or even 30 μm or less. Note that when 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. Protective layer 11 having such physical properties is suitable for use in manufacturing electronic component devices through a DBG process. Similarly, it is suitable for use in manufacturing electronic component devices through a stealth processing step using a stealth dicing machine. The protective layer 11 does not need to have the above physical properties because it can be suitably used when manufacturing electronic component devices through a blade dicing process.

[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 used, for example, by being attached to the surface to be protected of the electronic component (a type of substrate). Examples of the electronic component include a semiconductor wafer, a semiconductor chip, a substrate such as a wiring circuit board, a connected wiring circuit board formed by connecting a plurality of wiring circuit boards, and a pseudo wafer.

[0074] The semiconductor chip typically has a semiconductor chip body and electrodes disposed on one or both sides of the semiconductor chip body and electrically connected to electrodes of another component, such as a wiring circuit board or another semiconductor chip. The semiconductor chip has, for example, at least one surface formed with a circuit surface on which a circuit is formed. Specifically, the semiconductor chip may be a TSV (Through Silicon Via) type semiconductor chip having a pair of electrode portions arranged on both sides of the semiconductor chip body, and a conductive portion that penetrates the semiconductor chip body in the thickness direction so as to electrically connect one of the electrode portions to the other. In a TSV type semiconductor chip, a circuit surface may be formed on only one side, or a circuit surface may be formed on each of 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. This type of semiconductor chip is, for example, a sensor chip. Examples of the sensor chip include a CMOS (Complementary Metal-Oxide Semiconductor) chip and a MEMS (Micro Electro 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 by overlaying a protective layer 11 on the surface to be protected (protection step); a step of removing the protective layer 11 overlapping the surface to be protected (removal step), The protective layer 11 is The polymer includes 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, In the removal step, the acid is generated from a compound that generates the acid upon irradiation 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 above 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 protective layer 11. For example, after protective layer 11 of protective sheet 10 is superimposed on the surface to be protected of the substrate S, release liner 15 may be peeled off from protective layer 11 (see Figure 2B).

[0080] As shown in FIGS. 2C and 2D , the manufacturing method of the electronic component device of this embodiment further includes: The method may include a step of dividing the stack of the overlapping substrate S and protective layer 11 into small pieces at intervals in the surface direction to produce a plurality of stacked small pieces of chips S' formed by dividing the substrate into small pieces and small pieces 11' of the protective layer. Note that the substrate S before division may have a weak part or the like formed inside for dividing into small pieces.

[0081] In the above-mentioned removal process, as shown in Figure 2E, multiple small pieces 11' of the protective layer are irradiated with active energy rays such as ultraviolet rays, thereby generating new acids from the acid-generating compounds contained in each small piece 11', and the newly generated acids hydrolyze the easily hydrolyzable ester groups, thereby increasing the hydrophilicity of each small piece 11'. Then, in the above-mentioned removal step, each small piece 11' of the protective layer overlapping the circuit surface of the chip S' is removed by a liquid containing water, as shown in FIG. 2F. The method for manufacturing an electronic component device of 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 MOS (CMOS), or a device including a device (MEMS Micro Electro Mechanical Systems) in which mechanical elements, sensors, actuators, or electronic circuits are integrated by microfabrication technology on a single silicon substrate, glass substrate, or organic material substrate. 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 only one surface of the substrate or may be both surfaces. Circuit components (described in detail below) may or may not be arranged 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, the sensor unit, and the 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, or on one side of the substrate on which the sensor unit is arranged, or 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, the sensor unit, or the electrode unit with the protective layer 11. Examples of the circuit component include circuit wiring, electrodes, or elements such as transistors, diodes, and sensors (light-receiving sensors, vibration sensors, etc.).

[0086] Hereinafter, a detailed description will be given of 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 dividing 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 divided 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 method for manufacturing 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 method for manufacturing 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 a step (protection step) of 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, to protect the circuit surface (surface to be protected); a step of dividing a stack of overlapping semiconductor wafers (W) and protective layers (11) into small pieces at intervals in a surface direction, thereby producing a plurality of small pieces of a stack of semiconductor chips (X) obtained by dividing the semiconductor wafers (W) into small pieces and small pieces (11') of the protective layer that are overlapping each other; a step of irradiating each small piece 11' of the protective layer overlapping the circuit surface of the semiconductor chip X with active energy rays to generate an acid from the acid-generating compound in each small piece 11', hydrolyzing the easily hydrolyzable ester group with the acid, thereby increasing the number of hydrophilic groups in the molecule of the polymer and increasing the hydrophilicity of each small piece 11', and then removing each small piece 11' of the protective layer with a liquid containing water (removal step); and a step of bonding the semiconductor chip X to the adherend.

[0093] The assembly process of this example includes, for example, the following steps. Specifically, the assembly process of this example is as follows: a mounting step of attaching a semiconductor wafer W having circuit components formed on one side thereof to a dicing die bond film (a die bond sheet 30 superimposed on a dicing tape 20) to fix the semiconductor wafer W to the dicing die bond film; a protection step of protecting the circuit surface by attaching a protection layer 11 to the circuit surface of the semiconductor wafer W; a blade dicing process (a process for producing a plurality of small pieces of the laminate) in which the semiconductor wafer W to which the die bond sheet 30 and the protective layer 11 are attached is diced by a dicing blade T or the like to produce semiconductor chips (dies) by dicing the semiconductor wafer W; a removing step (the removing step) of removing the plurality of small pieces 11' of the protective layer attached to the semiconductor chip X after the irradiation treatment of the active energy rays as described above; a pick-up step of peeling the die-bonding sheet piece 30' from the dicing tape 20 to take out the semiconductor chip X with the die-bonding sheet piece 30' 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 its surface (for example, directions along its surface that are perpendicular to each other), thereby producing a plurality of semiconductor chips X. The semiconductor wafer W also 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 specific 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, there has been a demand for thinner semiconductor chips (for example, thicknesses of 20 μm to 50 μm). When viewed from one side in the thickness direction, the shape of a semiconductor chip is, for example, rectangular, 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 the protective layer 11 against the circuit surface to adhere it. 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 overlaying 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 the protective layer 11 is removed. Therefore, it is possible to prevent dust and the like from adhering to the circuit surface of the semiconductor wafer W covered with the protective layer 11. 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, for example, as shown in Figures 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 in a conventional manner, for example, using a dicing blade T. In the blade dicing process, for example, a cutting method called full cut, in which the cut is made up to the die bond sheet 30, can be used. The dicing device used in the blade dicing process is not particularly limited, and conventionally known devices can be used. In the blade dicing process, foreign matter such as debris may be generated when the semiconductor wafer W is cut. At this time, the surface to be protected of the semiconductor wafer W is protected by the protective layer 11, so that the adhesion of foreign matter to the surface to be protected can be suppressed. Before the blade dicing process, the 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, such as irradiation with active energy rays. In the irradiation treatment of active energy rays, for example, 10 mW / cm 2 More than 300mW / cm 2 UV rays with an intensity of less than 50mJ / cm are used as active energy rays. 2 More than 5000mJ / cm 2 The protective layer pieces 11' are irradiated with ultraviolet light as follows. In the removal step, the above-described treatment is performed on the multiple small pieces 11' of the protective layer, whereby 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, 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' dissolves, making it relatively easy to remove the small pieces 11' from the surface of the semiconductor chip X.

[0100] In the removal process, as shown in Figure 4E, a liquid containing water is brought into contact with the multiple small pieces 11' of the protective layer, and at least a portion of each small piece 11' is dissolved by the liquid, thereby removing each small piece 11' of the protective layer from the surface (surface to be protected) of the semiconductor chip X. By removing the small pieces 11' of the protective layer in this manner, all of the small pieces 11' of the protective layer can be removed relatively easily, and the number of foreign matters adhering to the semiconductor chip surface can be reduced relatively easily using the liquid. In addition, the surface (surface to be protected) of each semiconductor chip X on which the small pieces 11' of the protective layer overlapped can also be cleaned with the liquid.

[0101] In the removal step, at least a portion of the small pieces of the 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 is weakened, 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, and 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, in addition to water, a component that dissolves in water. Examples of such components include water-soluble organic solvents. Examples of such water-soluble organic solvents include monohydric alcohols having four or fewer 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] In the pick-up process, as shown in Fig. 4F, 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] When performing the pick-up step in this way, it is necessary that the pieces 30' of the die bond sheet attached to the semiconductor chip X be easily peeled off from the adhesive fixing layer 22 of the dicing tape 20. Furthermore, when performing the above-mentioned expanding step, it is necessary to stretch the dicing tape 20 so that the die bond sheet 30, the semiconductor wafer W, and the protective layer 11 are suitably divided into small pieces as necessary. The above-mentioned dicing tape 20 is designed to be able to satisfactorily exhibit such performance. For example, the dicing tape 20 is configured so that, when irradiated with active energy rays (e.g., ultraviolet rays), the adhesive fixing layer 22 hardens and the adhesive strength of the adhesive fixing layer 22 decreases. Since the adhesive fixing layer 22 hardens after irradiation, the adhesive strength of the adhesive fixing layer 22 can be reduced, and therefore the semiconductor chip X and the small piece 30′ of the die bond sheet can be relatively easily peeled off from the adhesive fixing layer 22 after irradiation. Dicing tapes 20 configured in this way 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'. 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 a plurality of semiconductor chips X as described above in the bonding process, the semiconductor chips X are stacked in such a way that adhesion of foreign matter to the circuit surfaces is suppressed, and therefore the number of foreign matter entering between one stacked semiconductor chip X and the other stacked semiconductor chip X can be reduced. The adherend Z may be, for example, an interposer, a wiring circuit board, or a small piece of substrate (when small pieces of 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 performed 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 is diced into small pieces by a blade dicing process, but 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 half-cut processing, 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-cut process, for example, as shown in FIGS. 4H to 4K, a wafer processing tape E is attached to the surface of the semiconductor wafer W opposite the circuit surface. With the wafer processing tape E attached, grooves for division are formed. A back-grinding tape B is attached to the surface with the grooves formed, while the wafer processing tape E that was initially attached is peeled off. With the back-grinding tape B attached, the semiconductor wafer W is ground until it reaches a predetermined thickness. Then, a mounting process is performed, and the semiconductor device is then 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] The protective sheet according to the embodiment of the present invention is as exemplified above, but the present invention is not limited to the above example. That is, 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 matters disclosed by this specification include the following. (1) a protective layer for protecting the surface of the substrate to be protected when manufacturing the electronic component device; The protective layer comprises a polymer having a glass transition temperature of 10°C or higher and 50°C or lower. (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 was irradiated with active energy rays at 1 J / cm 2 from a high-pressure mercury lamp. 2 The protective sheet according to any one of (1) to (3) above, which has an adhesive strength of 1.0 N / 10 mm or less to a silicon wafer after being irradiated with the above-mentioned radiation. (5) the protective layer further contains a compound that generates an acid when irradiated with active energy rays, The protective sheet according to any one of (1) to (4) above, wherein the polymer has an ester group in the molecule that is hydrolyzed by the acid to produce a hydrophilic group. (6) The protective sheet according to (5) above, wherein the polymer has, in the molecule, a structural unit of a (meth)acrylic acid ester monomer that generates a carboxyl group as the hydrophilic group in response to the acid. [Example]

[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 material> Details of the monomers used for polymerisation are as follows: [BEA] n-Butoxyethyl acrylate (see formula (A) below, purchased product) [ka] [PEA] n-Propyl ethyl acrylate (see formula (B) below, purchased product) [ka] [CHEA] Cyclohexylethyl acrylate (see formula (C) below, purchased product) [ka] [BEMA] n-Butoxyethyl methacrylate (see formula (D) below, purchased product) [ka] <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] (Polymer Preparation) 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 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 an acrylic polymer.

[0120] (Preparation of protective sheet) 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" San-Apro Co., Ltd. 50% by weight solution of 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" San-Apro Co., Ltd. 50% by weight solution of propylene carbonate Chemical Name:Diphenyl[4-(phenylsulfanyl)phenyl]sulfonium trifluorotris(pentafluoroethyl)-λ 5 -Phosphanoid [Also known as: Diphenyl[4-(phenylthio)phenyl]sulfonium, trifluorotris(1,1,2,2,2-pentafluoroethyl)phosphate(1-) (1:1)]

[0122] [Table 1]

[0123] <Physical properties: Glass transition temperature (Tg) of acrylic polymer (before UV irradiation treatment)> The glass transition temperature (Tg) of each acrylic polymer was measured by differential scanning calorimetry (DSC) according to the method for measuring glass transition temperature described above. The measurement results of glass transition temperature (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 the silicon wafer was measured as follows, and the tackiness of the protective layer at room temperature was evaluated. First, a backing tape was attached to each protective layer, and then the tape was 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 end of the sheet-like test sample in the longitudinal direction was gripped with a chuck, and a 180° peel test (peel test) was performed at room temperature (23°C) by peeling the test sample at a speed 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° peel test was carried out in the same manner as in the above-mentioned evaluation method for tackiness, except that the protective layer of the prepared test sample was attached to a silicon bare wafer at 70°C. The adhesive strength after irradiation with active energy rays was measured by attaching a test sample to a bare silicon wafer at 70°C and irradiating the backing tape with ultraviolet light (1 J / cm 2 ) and then measured in the same manner as above.

[0126] <Evaluation: Removability of protective layer (water solubility) (after UV irradiation)> Each protective layer was attached to a 6-inch diameter bare silicon wafer at 70°C, and the bare silicon wafer was then attached to a dicing tape. The test sample thus prepared was then attached to a dicing ring. For the protective layer, 0.5 or 1.0 [J / cm 2 ] using a high-pressure mercury lamp 2 ] irradiation treatment (light irradiation treatment including ultraviolet light) was performed to enhance the hydrophilicity of the protective layer. To remove the protective layer, a cleaning unit manufactured by DISCO (product name DFD6361) was used to spray 25°C water onto the bare silicon wafer while rotating the circular stage supporting the dicing tape from below. The stage rotation speed was 1500 rpm, and the water spraying time was 180 seconds. Then, whether the protective layer was peeled off and removed from the substrate (bare silicon wafer) was evaluated according to the following evaluation criteria. (Excellent) ○ All protective layers removed (Good) △ Most of the protective layer was removed, but some remained (less than 10% of the total area was confirmed to remain) (Poor) × The protective layer was not removed at all or most of it remained (more than 10% of the total area was confirmed to remain)

[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. [Industrial Applicability]

[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. [Explanation of symbols]

[0130] 10: Protective sheet, 11: protective layer, 11': small piece of protective layer, 15: release liner, 20: dicing tape, 21: Base material 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: Back grind tape.

Claims

1. a protective layer for protecting the surface of the substrate to be protected when manufacturing the electronic component device; The protective layer comprises 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 attached 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. The protective layer was 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 layer further contains a compound that generates an acid when irradiated with active energy rays, The protective sheet according to claim 1 or 2, wherein the polymer has an ester group in the molecule that is hydrolyzed by the acid to produce a hydrophilic group.

6. The protective sheet according to claim 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 in response to the acid.

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