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, for example, in the manufacture of electronic component devices such as semiconductor integrated circuits. [Background technology]

[0002] Conventionally, there are known methods for manufacturing electronic components, such as semiconductor integrated circuits. In this type of electronic component manufacturing method, for example, a substrate such as a silicon wafer is divided into smaller pieces to produce a large number of chips. During this type of processing, when the substrate is divided into smaller pieces, a small portion of the substrate may become a minute fragment, resulting in the generation of minute foreign matter. If circuit components such as circuit wiring or electrodes are located 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 no circuit components such as circuit wiring or electrodes are located. If 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 or not circuit components are located on the side where the foreign matter is attached.

[0003] In contrast, a surface protection sheet is known that has a protective layer that is attached to at least one surface of a substrate and removed after protecting the substrate (for example, Patent Document 1). The protective layer of the surface protection sheet described in Patent Document 1 includes a polymer such as polyvinyl alcohol and a compound that produces an acid or base upon irradiation 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, and protects the surface to be protected when the substrate is processed. After the surface to be protected is protected, the protective layer is removed and used. Specifically, the protective layer contains a compound that generates the acid or base described above, and the acid or base is generated by the active energy rays irradiated after the substrate is processed, thereby increasing the hydrophilicity of the protective layer. Therefore, the protective layer is removed with water or the like after the surface to be protected has been protected. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2023 / 195445 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, the protective layer described in Patent Document 1 does not always adhere sufficiently to the substrate or other object to be protected, and the protective layer may unintentionally peel off from the protected surface due to the force applied when processing the substrate or other object. On the other hand, if the hydrophilicity of the polymer is increased in order to improve the adhesion of the protective layer, the tackiness (stickiness) of the protective layer at room temperature increases, which may cause foreign matter to adhere to the protective layer unintentionally, or make it difficult to remove the 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 need for a protective sheet that has a protective layer that can achieve both low tackiness at room temperature and relatively strong adhesion to the surface to be protected, such as a substrate during processing.

[0008] However, protective sheets that have low tackiness at room temperature and a protective layer that adheres relatively strongly to the surface to be protected have not yet been sufficiently studied.

[0009] Therefore, the 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] To solve the above problems, the protective sheet according to the present invention is When manufacturing electronic component devices, a protective layer is provided to protect the surface of the circuit board to be protected. The protective layer comprises a polymer having a glass transition temperature of 10°C to 50°C. [Effects of the Invention]

[0011] The protective sheet according to the present invention provides a protective layer that has low tackiness at room temperature and adheres relatively strongly to the surface to be protected. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic cross-sectional view of an example of the protective sheet of this embodiment, cut in the thickness direction. [Figure 2A] A schematic cross-sectional view showing an example of the protection process in the manufacturing method of the electronic component device according to this embodiment. [Figure 2B] A schematic cross-sectional view showing an example of the protection process in the manufacturing method of the electronic component device according to this embodiment. [Figure 2C] A schematic cross-sectional view showing an example of the state of the substrate before it is cut in the manufacturing method of the electronic component device of this embodiment. [Figure 2D] A schematic cross-sectional view showing an example of the state after the substrate has been cut in the manufacturing method of the electronic component device of this embodiment. [Figure 2E] A schematic cross-sectional view showing an example of the removal process in the manufacturing method of the electronic component device according to this embodiment. [Figure 2F] A schematic cross-sectional view showing an example of the removal process in the manufacturing method of the electronic component device according to this embodiment. [Figure 3A] A cross-sectional view of an example of dicing tape, cut in the thickness direction. [Figure 3B] Cross-sectional view of an example of a dicing die bond film cut in the thickness direction. [Figure 4A] Cross-sectional view schematically showing the state after performing the mounting process and the protection process in a specific example of the method for manufacturing an electronic component device. [Figure 4B] Cross-sectional view schematically showing the state during the blade dicing process in a specific example of the method for manufacturing an electronic component device. [Figure 4C] Cross-sectional view schematically showing the state after performing the blade dicing process in a specific example of the method for manufacturing an electronic component device. [Figure 4D] Cross-sectional view schematically showing the state of the removal process in a specific example of the method for manufacturing an electronic component device. [Figure 4E] Cross-sectional view schematically showing the state of the removal process in a specific example of the method for manufacturing an electronic component device. [Figure 4F] Cross-sectional view schematically showing the state of the pickup process in a specific example of the method for manufacturing an electronic component device. [Figure 4G] Cross-sectional view schematically showing the state of the bonding process in a specific example of the method for manufacturing an electronic component device. <目标文本内容缺少,无法翻译,原内容为 [Figure 4H] Cross-sectional view schematically showing the state of the half-cut process of a semiconductor wafer in another specific example of the method for manufacturing an electronic component device. [Figure 4I] Cross-sectional view schematically showing the state of the half-cut process of a semiconductor wafer in another specific example of the method for manufacturing an electronic component device. [Figure 4J] Cross-sectional view schematically showing the state of the half-cut process of a semiconductor wafer in another specific example of the method for manufacturing an electronic component device. [Figure 4K] Cross-sectional view schematically showing the state of the mounting process in another specific example of the method for manufacturing an electronic component device.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the protective sheet according to the present invention will be described with reference to the drawings. 注:原内容中ID=25处缺少目标文本内容,无法准确翻译。请补充完整后以便能准确翻译全部内容。

[0014] The protective sheet 10 comprises at least a protective layer 11, as shown in Figure 1. The protective sheet 10 of this embodiment may further comprise a release liner 15 that overlaps at least one side of the protective layer 11. The release liner 15 may overlap one or both sides of the protective layer 11. Please note that each figure in the drawings is a schematic representation and does not necessarily reflect the aspect ratio of the actual object. The same applies to the other drawings.

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

[0016] The protective layer 11 has flexibility that allows it to be deformed with relatively weak force. Furthermore, the protective layer 11 has adhesive properties that allow it to adhere to, for example, the surface of a substrate to be protected. In other words, the protective layer 11 can be used as a pressure-sensitive sheet-type adhesive that adheres to the surface to be protected by being pressed against it.

[0017] The protective layer 11 of the protective sheet 10 in this embodiment contains a polymer having a glass transition temperature of 10°C to 50°C. Preferably, the protective layer 11 further contains a compound that generates acid upon irradiation with active energy rays. Preferably, the polymer has ester groups (hereinafter also referred to as easily hydrolyzable ester groups) in its molecule that are hydrolyzed by the generated acid to produce hydrophilic groups. In other words, it is preferable that the polymer is a polymer compound that generates hydrophilic groups when the easily hydrolyzable ester groups in its molecule are hydrolyzed by the generated acid.

[0018] Examples of hydrophilic groups that can be formed from the above-mentioned easily hydrolyzable ester group (-C(O)O-) by the above-mentioned acid include carboxyl groups (-COOH) and hydroxyl groups (-OH). In other words, a carboxyl group or a hydroxyl group can be formed from the above-mentioned easily hydrolyzable ester group.

[0019] The above polymer preferably has constituent units of (meth)acrylic acid ester monomers in its molecule that generate a carboxyl group as a hydrophilic group when the acid is applied.

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

[0021] The protective layer 11 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 when bonded to a silicon wafer at 23°C. As the adhesive strength is reduced, the tackiness of the protective layer 11 at room temperature may be lower. Therefore, it may be possible to further suppress the adhesion of foreign matter to the protective layer 11, and to peel off the release liner attached to the protective layer 11 more easily. Consequently, the handling (ease of handling) of the protective layer 11 at room temperature may be improved. Furthermore, the above adhesive strength may be 0.01 N / 10 mm or higher.

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

[0023] 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 when bonded to a silicon wafer at 70°C. A higher adhesive strength can further improve the adhesion of the protective layer 11 to the surface to be protected. Furthermore, such adhesive strength may be 15.0 N / 10 mm or less, or 10.0 N / 10 mm or less.

[0024] The above adhesive strength (adhesion after bonding at 70°C) can be adjusted, for example, by changing the molecular weight of the polymer contained in the protective layer 11. Alternatively, the adhesive strength can also be adjusted by changing the type or composition ratio of monomers used to synthesize the polymer. Specifically, by appropriately increasing the proportion of monomers that lower the glass transition temperature, the glass transition temperature of the polymer can be lowered, thereby increasing the adhesive strength. Conversely, by decreasing the proportion of monomers that lower the glass transition temperature, the glass transition temperature of the polymer can be raised, thereby decreasing the adhesive strength.

[0025] The protective layer 11 is irradiated with active energy rays from a high-pressure mercury lamp at a rate of 1 J / cm². 2 After irradiation, the adhesive strength to the silicon wafer is preferably 1.0 N / 10 mm or less, more preferably 0.5 N / 10 mm or less, and even more preferably 0.1 N / 10 mm or less. A lower adhesive strength after irradiation with the active energy ray allows the protective layer 11 to be removed more easily after protecting the surface of the adherend. The protective layer 11 can be removed, for example, by peeling or by a liquid containing water.

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

[0027] The above adhesive strength measurements are all performed as follows: A backing tape (UV-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 silicon bare wafer at 23°C or 70°C. Using a tensile testing machine, one end of the sheet-like test sample in the longitudinal direction 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 silicon bare wafer at 70°C, and then irradiating it with ultraviolet light from the backing tape side (1 J / cm²). 2 ) After that, it is measured in the same manner as above.

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

[0029] By overlapping the protective layer 11 onto the surface to be protected, the protective layer 11 can adhere strongly to the substrate surface (the surface to be protected) until the protective layer is removed. Therefore, it is possible to prevent foreign matter from adhering to the surface to be protected. For example, even when processing is performed to break down the substrate and the protective layer 11 into smaller pieces while the protective layer 11 and the substrate are overlapping, the adhesion force prevents the protective layer 11 from peeling off the substrate as a result of the breaking down. In addition, it is possible to prevent foreign matter such as fragments that may be generated by the processing from adhering to the surface to be protected, thus protecting the surface to be protected.

[0030] In this embodiment, the acid-producing compound is, for example, an acid generator that produces acid upon irradiation with active energy rays. A photoacid generator that produces acid upon irradiation with active energy rays (particularly ultraviolet light) is preferred as the acid-producing compound.

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

[0032] If the protective layer 11 contains the acid-producing compound described above, irradiating the protective layer 11 with active energy rays will generate acid from the acid-producing compound. This causes the easily hydrolyzable ester groups in the polymer molecules to hydrolyze, increasing the number of hydrophilic groups in the polymer and significantly increasing the hydrophilicity of the protective layer 11. The protective layer 11, with its significantly increased hydrophilicity, can be relatively easily peeled off the protected surface by contact with a liquid containing water. Therefore, the protective layer 11 can be easily removed from the protected surface. Thus, when the protective layer 11 contains the acid-producing compound and the polymer containing the easily hydrolyzable ester group, it can not only adhere sufficiently to the protected surface of the substrate, which is a component of the manufactured electronic device, but can also be removed relatively easily from the protected surface with a water-containing liquid after irradiation with active energy rays.

[0033] If the protective layer 11 contains the acid-producing compound mentioned above, it has the property of becoming more hydrophilic when irradiated with active energy rays such as ultraviolet light. The protective layer 11 only needs to have a predetermined level of hydrophilicity after the ester groups of the polymer are hydrolyzed. Therefore, in the state before the ester groups of the polymer are hydrolyzed, the hydrophilicity of the protective layer 11 may be less than or greater than the predetermined level. If the protective layer 11 has a predetermined level of hydrophilicity, at least a portion of the protective layer 11 may dissolve in a liquid containing water.

[0034] The above polymer has a glass transition temperature of 10°C to 50°C 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. A glass transition temperature higher than 10°C can result in lower tackiness of the protective layer 11 at room temperature. On the other hand, a glass transition temperature lower than 50°C has the advantage that the protective layer 11 can adhere relatively strongly to the surface to be protected without necessarily requiring heating when bonding the protective layer 11 to the surface to be protected.

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

[0036] The above polymers are irradiated with active energy rays (1 J / cm² using a high-pressure mercury lamp). 2 After irradiation, it preferably has a glass transition temperature of 30°C to 150°C. A higher glass transition temperature can improve the removal of the protective layer 11 with water or the like.

[0037] The glass transition temperature is measured as follows. Specifically, differential scanning calorimetry (DSC) is performed on the protective layer, and the glass transition temperature (Tg) is determined from the measurement chart. When determining the glass transition temperature (Tg) from the measurement chart, the "intermediate glass transition temperature (Tmg)" described in JIS K7121 (1987) "Method for Measuring Transition Temperatures of Plastics" is adopted as the glass transition temperature (Tg). <Measurement conditions> • Measurement temperature: -60℃ to 100℃ • Sample quantity to measure: Weigh out 5-10 mg. The glass transition point of the above polymer after irradiation with active energy rays, as described above, is a measurement taken after irradiation under the following conditions. Activated energy ray irradiation treatment: 1 J / cm using a high-pressure mercury lamp. 2 irradiation

[0038] From another perspective, the polymer described above is preferably a polymer compound having hydrophilic groups (such as carboxyl groups) in its molecule that are protected by a protecting group but deprotected by the acid described above. The protecting group is present in the polymer in a state where it is chemically bonded to the hydrophilic group.

[0039] Examples of protective groups that can protect the hydrophilic groups mentioned above include the following: Examples of protecting groups that can protect a carboxyl group include tert-butyl groups, alkoxyalkyl groups, or cyclic acetal groups (groups containing a dioxolane structure). Examples of alkoxyalkyl groups include methoxymethyl groups, ethoxyethyl groups, or butoxyethyl groups. In an alkoxyalkyl group, the number of consecutively bonded carbon atoms may be between 2 and 4. Examples of protecting groups that can protect a hydroxyl group include trityl groups, alkoxymethyl groups, tetrahydropyranyl groups, cyclic acetal groups (groups containing dioxolane structures), tert-butyldimethylsilyl groups, or tert-butoxycarbonyl groups.

[0040] It should be noted that the above notation for protecting groups does not necessarily directly represent the state in which the hydrophilic group and the protecting group are bonded. For example, if the hydrophilic group is a carboxyl group and the protecting group is a tert-butyl group, an ester bond exists formed by the reaction of the carboxyl group with tert-butyl alcohol, but even in such cases, the protecting group is still described as a tert-butyl group. Furthermore, the protected hydrophilic group is also described using its name before protection.

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

[0042] The above polymer may have ester groups (easily hydrolyzable ester groups) of the constituent units of (meth)acrylic acid ester type monomers in its molecule. In other words, the above polymer may be a polymer (hereinafter simply referred to as acrylic polymer) obtained by polymerizing (meth)acrylic acid ester type monomers containing at least easily hydrolyzable ester groups. In this specification, the term "(meth)acrylic acid" encompasses both acrylic acid and methacrylic acid. The same applies to "(meth)acrylate."

[0043] The above-mentioned acrylic polymer has, for example, a main chain and a plurality of side chains in its molecule. The main chain is a covalent chain formed, for example, by a radical polymerization reaction. Preferably, at least a portion of the main chain is a covalent chain formed by a polymerization reaction of (meth)acrylic acid ester type monomers containing easily hydrolyzable ester groups. The side chains have readily hydrolyzable ester groups, for example, formed by the dehydration condensation of a carboxyl group acting as a hydrophilic group. From another perspective, in the side chains of acrylic polymers, the carboxyl group acting as a hydrophilic group, which is generated by the above-mentioned acid, is protected by a protecting group to become a readily hydrolyzable ester group.

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

[0045] Examples of constituent units of the (meth)acrylic acid ester type monomer (containing an easily hydrolyzable ester group) that the above-mentioned acrylic polymer has in its molecule include the constituent units of the following monomers. • tert-butyl (meth)acrylate [(meth)acrylate t-butyl ester] • Alkoxyalkyl (meth)acrylate [(meth)acrylate alkoxyalkyl ester] (represented by the following general formula (I)) [ka]

[0046] Examples of alkoxyalkyl (meth)acrylates represented by the above general formula (I) include n-propylethyl acrylate [propoxyethyl (meth)acrylate], n-butoxyethyl (meth)acrylate [1-butoxyethyl (meth)acrylate], or cyclohexylethyl acrylate [cycloalkoxyethyl (meth)acrylate].

[0047] When the above-mentioned acrylic polymer contains readily hydrolyzable ester groups in its molecule, the hydrophilicity of the protective layer containing the acrylic polymer is low. Therefore, even when in contact with a solvent containing water, the protective layer is not removed from the surface to be protected and continues to protect the surface. Moreover, because the polymer molecule contains many 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 produced by such irradiation, generating carboxyl groups and the like. In other words, the protected carboxyl groups and the like are deprotected. As a result, the hydrophilicity of the protective layer 11 increases, and the protective layer 11 can be removed relatively easily from the protected surface with a liquid containing water.

[0048] The constituent units of the above (meth)acrylic acid ester type monomer contain an easily hydrolyzable ester group, and after hydrolysis, they yield constituent units of either acrylic acid monomer or methacrylic acid monomer. In other words, the constituent units of the above (meth)acrylic acid ester type monomer have a molecular structure in which the carboxyl group in each constituent unit of the acrylic acid monomer or methacrylic acid monomer is protected by a protecting group.

[0049] The above acrylic polymer preferably contains 50% by mass or more of the above (meth)acrylic acid ester type monomer constituent units (containing easily hydrolyzable ester groups) in its molecule, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The above acrylic polymer may also contain 95% by mass or more of the above (meth)acrylic acid ester type monomer constituent units (containing easily hydrolyzable ester groups). The acrylic polymer described above contains a greater number of constituent units of the (meth)acrylic acid ester type monomer, allowing the protective layer 11 to adhere more strongly to the surface to be protected. On the other hand, when the protective layer 11 is subjected to active energy ray irradiation in the removal process (described in detail later), the acid generated from the photoacid generator, etc., hydrolyzes the easily hydrolyzable ester groups, generating many new carboxyl groups. Therefore, the protective layer 11 can be removed more easily with a liquid containing water.

[0050] Examples of monomers that can copolymerize with the above-mentioned (meth)acrylic acid ester type monomers include vinyl acetate, alkyl (meth)acrylate [(meth)acrylate alkyl ester], hydroxyalkyl (meth)acrylate [(meth)acrylate hydroxyalkyl ester], carboxyalkyl (meth)acrylate [(meth)acrylate carboxyalkyl ester], (meth)acrylic acid, N-(hydroxyalkyl)(meth)acrylamide, and (meth)acrylate having a polyethylene glycol chain. In other words, the above-mentioned acrylic polymer may have, in addition to the constituent units of the above-mentioned (meth)acrylic acid ester type monomer, each of the constituent units of the monomers listed above in its molecule.

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

[0052] In this embodiment, the compound that generates the above-mentioned acid is a compound that generates a new acid by irradiation with active energy rays. The irradiation treatment using active energy rays will be described in detail later.

[0053] Examples of compounds that produce the above-mentioned acid include photoacid generators. When the above-mentioned acid-producing compound generates acid upon light irradiation, at least a portion of the easily hydrolyzable ester groups in the polymer contained in the protective layer 11 is hydrolyzed, and hydrophilic groups such as carboxyl groups are exposed. This increases the hydrophilicity of the protective layer 11. Therefore, the protective layer 11 can be easily removed from the protected surface by contact with a liquid containing water.

[0054] Photoacid generators, used as acid generators, are, for example, photocationic polymerization initiators commonly used for cationic polymerization. Commercially available products can be used as the photoacid generator mentioned above.

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

[0056] Examples of onium salt compounds include iodonium salt compounds, sulfonium salt compounds, oxime sulfonate compounds, and diazonium salt compounds. Among these, iodonium salt compounds or sulfonium salt compounds are preferred, and sulfonium salt compounds are more preferred, because they produce a stronger acid (stronger acid) and can generate hydrophilic groups from the polar groups of the polymer even with a small amount of use.

[0057] Examples of iodonium salt compounds include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, bis(4-tert-butylphenyl)iodonium hexafluorophosphate, diphenyliodonium trifluoromethanesulfate, diphenyliodonium nonafluoron-butanesulfonate, diphenyliodonium perfluoron-octanesulfonate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, diphenyliodonium camphor sulfonate, bis(4-tert-butylphenyl)iodonium camphor sulfonate, bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, bis(4-fluorophenyl)iodonium triflate, and diphenyliodonium hexafluorophosphate. 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 5Examples include phosphanoids, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium nonafluoron-butanesulfonate, triphenylsulfonium camphorsulfonate, 4,7-di-n-butoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium adamantane carboxylate 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, and triphenylsulfonium hydroxide. Other examples include the sulfonium salt compounds used in the following examples (for instance, "CPI-310FG" manufactured by Sunapro).

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

[0060] Examples of diazonium salt compounds include 4-nitrobenzenediazonium tetrafluoroborate.

[0061] Examples of commercially available onium salt compounds include, for example, Optomer SP-150, Optomer SP-170, Optomer SP-171 (all manufactured by ADEKA), UVE-1014 (manufactured by General Electronics), OMNICAT250, OMNICAT270 (both manufactured by IGMresin), IRGACURE290 (manufactured by BASF), SunAid SI-60L, SunAid SI-80L, SunAid SI-100L (all manufactured by Sanshin Chemical Industry Co., Ltd.), CPI-100B, CPI-100P, CPI-101A, CPI-200K (all manufactured by SunApro Co., Ltd.).

[0062] Examples of sulfonimide compounds used as photoacid generators include N-(trifluoromethanesulfonyloxy)succinimide, N-(nonafluoron-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 disulfonyl diazomethane compounds used 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-mentioned polymer. An ionic photoacid generator is preferred as the photoacid generator.

[0066] In the protective layer 11, the amount of the acid-producing 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, the protective layer 11 is more easily removed by liquids containing water. The amount of the acid-producing 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 makes it possible to more effectively suppress the residue of the acid-producing compound 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 solvents include water or an organic solvent. As the organic solvent, a relatively volatile organic solvent is preferred. 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 and the thermal polymerization initiator. When this reaction occurs, hydrophilic groups that would normally be formed after hydrolysis may not be formed. Therefore, the protective layer may have difficulty maintaining its hydrophilicity even after being treated with active energy rays. Consequently, it may be difficult to remove the protective layer with a liquid containing water.

[0069] The protective layer 11 of this embodiment may be produced by mixing the polymer described above, an acid-generating compound such as the photoacid generator described above, and a solvent as needed, in a general manner to obtain a protective layer-forming composition, and then volatilizing the solvent.

[0070] The protective layer 11 may be formed, for example, by applying the above-mentioned protective layer-forming composition containing a solvent 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 protective layer-forming composition containing a solvent to one side of the release liner 15, and then volatilizing the solvent. Preferably, the formed protective layer 11 does not contain a solvent that has been added to the above-mentioned protective layer-forming composition to impart fluidity. The protective layer 11 may also be formed, for example, from the above-mentioned protective layer-forming composition that does not contain a solvent, by a general molding method.

[0071] In the protective sheet described above, the thickness of the 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. Such a thickness may also be 40 μm or less, 30 μm or less, or 30 μm or less. If the protective layer 11 is a laminate, the above thickness is the total thickness of the laminate.

[0072] The protective layer 11 described above may have the property of being stretched in the planar direction and fragmented into smaller pieces before being irradiated with active energy rays. A protective layer 11 having such properties is preferably used when manufacturing electronic components and devices via a DBG process. Similarly, it is preferably used when manufacturing electronic components and devices via a stealth processing process using a stealth dicing apparatus. Furthermore, since the protective layer 11 described above can also be suitably used when manufacturing electronic component devices through a blade dicing process, it does not necessarily have to possess the physical properties described above.

[0073] The protective sheet 10 of this embodiment is used, for example, in the process of manufacturing electronic component devices. Specifically, the protective sheet 10 of this embodiment is used for purposes such as temporarily protecting the protected surface (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 by being attached to the protected surface of an electronic component (a type of substrate), for example. Examples of the electronic components mentioned above include semiconductor wafers, semiconductor chips, substrates such as wiring circuit boards, interconnected wiring circuit boards formed by connecting multiple wiring circuit boards, or pseudo-wafers.

[0074] The semiconductor chip described above typically comprises a semiconductor chip body and electrode portions arranged on one or both sides of the semiconductor chip body and electrically connected to electrode portions of other components. Examples of other components include a wiring circuit board or other semiconductor chips. The semiconductor chip has, for example, a circuit surface on at least one side where a circuit is formed. Specifically, the semiconductor chip described above may be a TSV (Through Silicon Via) type semiconductor chip comprising 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 conduct electricity between one of the electrode portions and the other. In a TSV type semiconductor chip, the circuit surface may be formed on only one side, or the circuit surface may be formed on both sides. Furthermore, the semiconductor chip circuit may be equipped with sensor elements (for example, light-receiving elements or vibration elements). An example of this type of semiconductor chip is a sensor chip. Examples of sensor chips include CMOS (Complementary Metal-Oxide Semiconductor) chips and MEMS (Micro Electro Systems) chips.

[0075] The pseudo-wafer described above comprises, for example, a support substrate and a package in which a plurality of semiconductor chips arranged on the support substrate are collectively sealed in resin. The pseudo-wafer may also be the package removed from the support substrate. A redistribution 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 such redistribution layer. Note that the divided pseudo-wafer, each containing at least one semiconductor chip, may be an electronic component.

[0076] As mentioned above, there are various types of electronic components that have a surface to be protected, and various electronic components can serve as substrates.

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

[0078] The manufacturing method of the above-mentioned electronic component device is: A step of protecting the surface to be protected by overlapping a protective layer 11 onto at least one of the two surfaces of the substrate that is to be protected (protection step), The process includes removing the protective layer 11 that overlaps the surface to be protected (removal step), The protective layer 11 is The present invention comprises a compound that generates an acid upon irradiation with active energy rays, and the above-mentioned polymer having an ester group in its molecule that is hydrolyzed by the acid to produce a hydrophilic group, In the removal step, the acid is generated from the acid-producing compound by irradiation with active energy rays, thereby hydrolyzing the ester group (easily hydrolyzable ester group) to increase the hydrophilicity of the protective layer 11, and the protective layer 11 is removed by bringing the protective layer 11 into contact with a liquid containing water.

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

[0080] The manufacturing method of the electronic component device of this embodiment is further as shown in Figures 2C and 2D, The process may include a step of dividing the stacked substrate S and protective layer 11 into smaller pieces with spacing in the planar direction, thereby producing multiple small pieces of the stacked material in which the small pieces of substrate chips S' and small pieces of protective layer 11' overlap. Note that before division, the substrate S may have weakened areas or other structures formed inside to facilitate fragmentation.

[0081] In the removal process described above, as shown in Figure 2E, by irradiating multiple small pieces 11' of the protective layer with active energy rays such as ultraviolet light, new acid is generated from the acid-producing compound contained in each small piece 11', and the easily hydrolyzable ester group is hydrolyzed by the newly generated acid, thereby increasing the hydrophilicity of each small piece 11'. Then, in the removal process described above, as shown in Figure 2F, each small piece 11' of the protective layer overlapping the circuit surface of the chip S' is removed with a liquid containing water. Furthermore, the manufacturing method of the electronic component device according to this embodiment may further include the step of arranging the circuit surface of the chip S' facing the adherend and joining the chip S' and the adherend.

[0082] The electronic component device manufactured by the manufacturing method of this embodiment comprises at least one of the various electronic components described above. Examples of electronic component devices include semiconductor devices such as semiconductor integrated circuits equipped with semiconductor chips, devices equipped with system LSIs having complementary MOS (CMOS), or devices equipped with MEMS (Micro Electro Mechanical Systems) in which mechanical components, sensors, actuators, or electronic circuits are integrated on a single silicon substrate, glass substrate, or organic material substrate by microfabrication technology. The manufactured electronic component device may also be a device equipped with 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 protected surface (hereinafter also simply referred to as the protected surface) may be only one side of the substrate or both sides. Circuit components (described in detail later) may or may not be arranged on the protected surface.

[0084] The substrate is not particularly limited in material as long as it is in the form of a plate. Examples of substrate materials include glass, silicon, stainless steel (SUS), plastic, or ceramic. Examples of substrates include semiconductor wafers, sensor wafers such as CMOS or MEMS, pseudo-wafers, or wiring circuit boards.

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

[0086] The following provides a detailed explanation of the process of manufacturing semiconductor integrated circuits (semiconductor devices) as electronic components.

[0087] Generally, a semiconductor device manufacturing method comprises 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 on it and assembled.

[0088] In the subsequent process, for example, a weak area is formed on the wafer (semiconductor wafer) that has a circuit surface formed on it, in order to break it into smaller semiconductor chips (dies), and the adhesive fixing layer of dicing tape is attached to the side opposite to 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, thereby breaking the semiconductor wafer into smaller semiconductor chips using the weak area as the boundary. After that, the small semiconductor chips are peeled off from the adhesive fixing layer of the dicing tape.

[0089] The subsequent processes described above include, for example, a stealth processing step in which a fragile area is formed on the wafer using laser light or the like to break down the wafer into smaller chips (dies); a mounting step in which the semiconductor wafer is fixed by attaching the side of the semiconductor wafer opposite to the circuit side to a dicing tape; an expanding step in which the semiconductor wafer is broken down into semiconductor chips (dies) by stretching the dicing tape in the planar direction; a pick-up step in which the semiconductor chip is peeled off and removed from the adhesive fixing layer; and a bonding step in which the removed semiconductor chip is bonded to a substrate. Semiconductor integrated circuits (semiconductor devices) are manufactured, for example, through these processes.

[0090] In the semiconductor device (electronic component device) manufacturing method of this embodiment, for example, semiconductor chips are cut out from a semiconductor wafer on which a circuit surface has been formed, and a semiconductor device having the cut-out semiconductor chips is assembled. In the semiconductor device manufacturing method of this embodiment, the protective layer 11 of the protective sheet 10 and the dicing tape 20 (see Figure 3A) are used at least to manufacture the semiconductor device as follows. These sheets and tapes are used as auxiliary tools for manufacturing the semiconductor device. Note that 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 can also be used (see Figure 3B). Commercially available products can be used as the dicing tape 20 and the dicing die bond film.

[0091] The following provides a detailed explanation of a specific example of a semiconductor device manufacturing method.

[0092] The semiconductor device manufacturing method in this specific example includes an assembly step of cutting out a semiconductor chip X from a semiconductor wafer W (substrate) on which a circuit surface is formed, and assembling a semiconductor device having the semiconductor chip X. Such an assembly process includes a step of protecting the circuit surface (surface to be protected) by superimposing a protective layer 11 for protecting the circuit components onto at least one surface of the semiconductor wafer W on which any of the circuit components are formed (protection step), A process to produce multiple small pieces of a laminate in which the semiconductor wafer W and protective layer 11 are stacked and overlapped by dividing the stacked semiconductor wafer W and protective layer 11 into small pieces with spacing in the planar direction, and The process involves irradiating each small piece 11' of the protective layer overlapping the circuit surface of the semiconductor chip X with an active energy ray to generate acid from the acid-producing compound in each small piece 11', hydrolyzing the easily hydrolyzable ester group with the acid, thereby increasing the hydrophilic groups in the polymer molecule and enhancing the hydrophilicity of each small piece 11', and then removing each small piece 11' of the protective layer with a water-containing liquid (removal step), The process includes a step of joining a semiconductor chip X to an adherend.

[0093] The assembly process of this specific example includes, for example, the following steps: Specifically, the assembly process in this example is: A mounting process involves attaching a semiconductor wafer W, on which circuit components are formed on one side, 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 to protect the circuit surface of a semiconductor wafer W by attaching a protective layer 11 to the circuit surface, A blade dicing process (a process for producing multiple small pieces of the above-mentioned laminate) involves dividing a semiconductor wafer W, to which a die bond sheet 30 and a protective layer 11 are attached, into small pieces using a dicing blade T or the like to create semiconductor chips (dies) from the semiconductor wafer W. After undergoing the irradiation treatment with active energy rays as described above, a removal step (the removal step described above) is performed to remove multiple small pieces 11' of the protective layer attached to the semiconductor chip X, A pickup process involves peeling off the small piece 30' of the die bond sheet from the dicing tape 20 to remove the semiconductor chip X with the small piece 30' of the die bond sheet still attached, The process includes a bonding step (the bonding step described above) in which the extracted semiconductor chip X is bonded to the adherend via a small piece 30' of the die bond sheet. When these steps are carried out, the dicing die bond film having the protective layer 11 and the dicing tape 20 described above is used as a manufacturing aid.

[0094] A semiconductor wafer W is configured to produce multiple semiconductor chips X. More specifically, the semiconductor wafer W is divided into smaller pieces with spacing in multiple directions along its surface (for example, directions along the surface that are mutually orthogonal), thereby enabling the fabrication of multiple semiconductor chips X. Furthermore, the semiconductor wafer W has a circuit surface on at least one of its surfaces 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 the semiconductor industry in recent years, with the further advancement of integration technology, there is a demand for thinner semiconductor chips (for example, with a thickness of 20 μm to 50 μm). The shape of a semiconductor chip when viewed from one side in the thickness direction is, for example, rectangular, and the length of one side is a predetermined length, for example, 5 mm to 20 mm.

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

[0097] In the protection process, for example, as shown in Figure 4A, a protective layer 11 is superimposed on one of the circuit surfaces of the semiconductor wafer W. In the protection process, the protective layer 11 may be superimposed on the circuit surface by, for example, directly pressing and attaching the protective layer 11 to the circuit surface. Alternatively, a protective layer forming composition containing a solid component constituting the protective layer 11 and a solvent for dissolving the solid component may be prepared, and after applying the prepared protective layer forming composition to the circuit surface, the solvent is evaporated to form a protective layer 11 that is 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 a protective layer 11 onto the circuit surface of a 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 other debris from adhering to the circuit surface of the semiconductor wafer W covered with the protective layer 11. Furthermore, the protection process may be performed after the mounting process, or the mounting process may be performed after the protection process.

[0098] In the blade dicing process, the semiconductor wafer W is diced, for example, as shown in Figures 4B and 4C. More specifically, the semiconductor wafer W is cut to a predetermined size together with the die bond sheet 30 to form a semiconductor chip with the die bond sheet 30. The blade dicing process is carried out according to a conventional method, for example, using a dicing blade T. In the blade dicing process, a cutting method called full cut, which cuts all the way to the die bond sheet 30, can be employed. The dicing apparatus used in the blade dicing process is not particularly limited, and conventionally known apparatus can be used. In the blade dicing process, foreign matter such as fragments may be generated when the semiconductor wafer W is cut. However, since the protective layer 11 protects the surface of the semiconductor wafer W, the adhesion of foreign matter to the protected surface can be suppressed. Alternatively, 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 fixed to the holder H of the expander.

[0099] In the removal step, as shown in FIG. 4D, a treatment for generating an acid from the compound that generates the acid is performed on a plurality of small pieces 11' of the protective layer. As such a treatment, an irradiation treatment with active energy rays is employed. In the irradiation treatment with active energy rays, for example, ultraviolet rays with an intensity of 10 mW / cm 2 or more and 300 mW / cm 2 or less are employed as the active energy rays, and the plurality of small pieces 11' of the protective layer are irradiated with ultraviolet rays so that the integrated light quantity is 50 mJ / cm 2 or more and 5000 mJ / cm 2 or less. In the removal step, by performing the above-described treatment on a plurality of small pieces 11' of the protective layer, an acid is generated from the compound that generates the acid contained in the small pieces 11'. The newly generated acid hydrolyzes the easily hydrolyzable ester group in the polymer contained in the small pieces 11' of the protective layer, and a hydrophilic group such as a carboxy group is newly generated. Thus, the hydrophilicity of the small pieces 11' of the protective layer is enhanced. Thereby, when the small pieces 11' and a liquid containing water come into contact later, at least a part 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, a liquid containing water is brought into contact with a plurality of small pieces 11' of the protective layer, and at least a part of each small piece 11' is dissolved with the above liquid, whereby each small piece 11' of the protective layer is removed from the surface (protected surface) of the semiconductor chip X. By removing the small pieces 11' of the protective layer in this manner, all of the plurality of small pieces 11' of the protective layer can be removed relatively easily, and the number of foreign substances adhering to the surface of the semiconductor chip can be reduced relatively easily with the above liquid. Also, the surface (protected surface) of each semiconductor chip X where the small pieces 11' of the protective layer overlapped can be washed with the liquid.

[0101] In the removal process, at least a portion of the fragmented protective layer (multiple small pieces 11' of the protective layer) is dissolved by the liquid. As a result, the adhesion of the small pieces 11' of the protective layer to the semiconductor chip X weakens, making them easier to peel off from the semiconductor chip X. This allows the multiple small pieces 11' of the protective layer to be removed relatively easily.

[0102] The liquid containing water 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. The above liquid may contain components that dissolve in water in addition to water. Examples of such components include water-soluble organic solvents. Examples of such water-soluble organic solvents include monohydric alcohols with 4 or fewer carbon atoms, such as methanol, ethanol, propanols such as isopropyl alcohol, or butanols such as tert-butanol.

[0103] In the removal step in 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 sprayed from a nozzle or the like may be brought into contact with the protective layer pieces 11'. 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 process, a disc-shaped stage supporting the dicing tape 20 from below is rotated circumferentially, and the liquid is sprayed onto the semiconductor chips X attached to each of the small pieces 30' of the die bond sheet. This removes multiple small pieces 11' of the protective layer that are superimposed on the semiconductor chips X. The rotation speed of the stage may be, for example, 500 rpm to 4000 rpm, the amount of liquid sprayed may be, for example, 0.05 L / min to 5.0 L / min, and the spraying time may be, for example, 5 seconds to 300 seconds.

[0105] In the semiconductor device manufacturing method of this specific example, a protective layer 11 is superimposed on the surface (circuit surface) of the semiconductor wafer W on which circuit components are formed, thus protecting the circuit surface until the protective layer 11 is removed. Specifically, since the semiconductor wafer W is cut into small pieces to produce a semiconductor chip X while the semiconductor wafer W and the protective layer 11 are superimposed, it is possible to prevent foreign matter such as fragments that may be generated due to the cleavage of the semiconductor wafer W from adhering to the circuit surface of the semiconductor chip X. Even if foreign matter is adhering to the circuit surface of the semiconductor chip X before the protective layer 11 is superimposed, that foreign matter can be removed when the small piece 11' of the protective layer superimposed on the circuit surface of the semiconductor chip X is removed. Therefore, it is possible to suppress the adhesion of foreign matter to the circuit surface of the manufactured semiconductor chip X. 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 will not be removed by liquids containing water because the hydrophilicity of the protective layer 11 is low before irradiation with active energy rays.

[0106] In the pickup process, as shown in Figure 4F, the semiconductor chip X is peeled from the adhesive fixing layer 22 of the dicing tape 20. Specifically, the pin member P is raised to push up the semiconductor chip X to be picked up via the dicing tape 20. The pushed-up semiconductor chip X is held by the suction jig J.

[0107] When performing the pickup process in this manner, it is necessary that the small 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 expansion process described above, it is necessary to stretch the dicing tape 20 to effectively break down 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 perform these functions. For example, the dicing tape 20 is configured such that when irradiated with active energy rays (e.g., ultraviolet light), the adhesive fixing layer 22 hardens, reducing the adhesive strength of the adhesive fixing layer 22. Because the adhesive strength of the adhesive fixing layer 22 can be reduced by hardening after irradiation, the semiconductor chip X and the small pieces 30' of the die bond sheet can be peeled off from the adhesive fixing layer 22 relatively easily after irradiation. Dicing tapes 20 with such a configuration are commercially available.

[0108] In the bonding process, the semiconductor chip X, with small pieces 30' of the die bond sheet attached, is bonded to the substrate Z. In other words, the semiconductor chip X is bonded to the substrate Z via the small pieces 30' of the die bond sheet. In the bonding process, as shown in Figure 4G, multiple semiconductor chips X with small pieces 30' of the die bond sheet attached may be stacked. In this specific example, the semiconductor chip X is bonded to the substrate or other substrate via the small pieces 30' of the die bond sheet. When stacking multiple semiconductor chips X as described above during the bonding process, the number of foreign objects that can get between one semiconductor chip X and the other is reduced because the stacking of multiple semiconductor chips X is such that the adhesion of foreign objects to the circuit surface is suppressed. Examples of the adherend Z include an interposer, a wiring circuit board, or a small piece of a substrate (when small pieces of substrate are stacked and laminated).

[0109] In this specific example, a resin encapsulation step may be performed to encapsulate (cover) the semiconductor chip X with a thermosetting resin or the like in order to protect the semiconductor chip X after the bonding process.

[0110] In the above explanation of this specific example, an example was given in which the semiconductor wafer W is cut into smaller pieces by a blade dicing process. However, the semiconductor wafer W may also be cut into smaller pieces by a so-called DBG process, which involves half-cutting the semiconductor wafer W and then thinning the thickness of the semiconductor wafer W. In half-cut processing, for example, grooves are formed in the semiconductor wafer W to process it into chips (dies) by a cutting process, and then the semiconductor wafer W is ground down to reduce its thickness. In the half-cut process, for example, as shown in Figures 4H to 4K, wafer processing tape E is attached to the side of the semiconductor wafer W opposite to the circuit side. With the wafer processing tape E attached, grooves for division are formed. Backgrind tape B is attached to the grooved side, while the wafer processing tape E that was initially attached is peeled off. With the backgrind tape B attached, the semiconductor wafer W is ground down until it reaches a predetermined thickness. Then, a mounting process is carried out, and after that, a semiconductor device is manufactured in the same manner as described above.

[0111] The semiconductor wafer W (substrate) before being cut into smaller pieces for semiconductor chips X may, for example, be ground to a desired thickness by backgrinding. Specifically, in backgrinding, a semiconductor wafer W with a backgrind tape B attached to the circuit surface may be ground to reduce the thickness of the semiconductor wafer W until it reaches the thickness of the semiconductor chip X to be manufactured later.

[0112] Other processes besides those shown in the specific examples above may be performed. For example, in processes such as plasma dicing or stealth dicing, a 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 placed between the backgrind tape B and the semiconductor wafer W as described above, grinding may be performed as described above, and then the mounting process may be performed.

[0113] The protective sheet in the embodiments of the present invention is as illustrated above, but the present invention is not limited to the above examples. In other words, various forms commonly used in protective sheets can be adopted, to the extent that 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 with circuit surfaces formed on both sides, or, as described in other embodiments, a semiconductor wafer with circuit surfaces formed on only one side. In other words, circuit components may be arranged on only one of the two sides of the semiconductor chip manufactured by the manufacturing method described above, or circuit components may be arranged on both sides.

[0115] The matters disclosed herein include the following: (1) When manufacturing electronic component devices, a protective layer is provided to protect the surface of the circuit board to be protected. The protective layer is a protective sheet containing a polymer having a glass transition temperature of 10°C to 50°C. (2) The protective layer is the protective sheet described in (1) above, which has an adhesive strength of 0.5 N / 10 mm or less when bonded to a silicon wafer at 23°C. (3) The protective layer is a protective sheet as described in (1) or (2) above, having an adhesive strength of 1.0 N / 10 mm or more when bonded to a silicon wafer at 70°C. (4) The protective layer is irradiated with active energy rays from a high-pressure mercury lamp at a rate of 1 J / cm². 2 A 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. (5) The protective layer further contains a compound that generates acid upon irradiation with active energy rays, The protective sheet according to any one of (1) to (4) above, wherein the polymer has an ester group in its molecule that is hydrolyzed by the acid to produce a hydrophilic group. (6) The protective sheet according to (5) above, wherein the polymer has constituent units of a (meth)acrylic acid ester monomer in its molecule that generate a carboxyl group as the hydrophilic group by the acid. [Examples]

[0116] The present invention will be further explained with experimental examples, but the present invention is not limited to these.

[0117] The protective layers for the examples and comparative examples were prepared as follows, and protective sheets equipped with these protective layers were manufactured. 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 polymer polymerization are as follows: • [BEA] n-butoxyethyl acrylate (See formula (A) below; purchased item) [ka] • [PEA] n-Propylethyl acrylate (See formula (B) below; purchased item) [ka] • [CHEA] Cyclohexylethyl acrylate (See formula (C) below; purchased item) [ka] • [BEMA] n-butoxyethyl methacrylate (See formula (D) below; purchased item) [ka] <Other monomers> • [4HBA] 4-hydroxybutyl acrylate (purchased item) • [HEAA] N-(2-hydroxyethyl)acrylamide (Purchased item)

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

[0120] (Making protective sheets) To the polymer solutions containing each acrylic polymer prepared as described above, an acid-generating compound (photoacid generator) was added and mixed in an amount shown in Table 1 relative to the polymer solids (except for Comparative Example 2). Each acrylic polymer solution was applied onto a release liner a (PET film, 50 μm thick). Each release liner a had a surface treated with silicone release agent, and the polymer solution was applied to this surface using an applicator. Furthermore, a drying treatment was performed at 130°C for 2 minutes to form a protective layer with a thickness of 5 μm overlapping one side of each release liner a. Then, release liner b (PET film, 38 μm thick) was placed on the exposed surface of each protective layer. Each release liner b also had a surface treated with silicone release agent, and this side was attached to the protective layer. In this way, protective sheets with a protective layer sandwiched between two release liners were prepared.

[0121] Details of the acid-generating compounds (photoacid generators) are as follows. Note that all of the raw materials listed below were used in the form of a 50% by mass solution in an organic solvent. • Sulfonium salt type. Product name: "CPI-310FG". Manufactured by Sunapro Co., Ltd. Solid content: 100% by mass (to be used after preparing a 50% by mass MEK solution). • Sulfonium salt type Product name "CPI-410B" Manufactured by Sunapro Co., Ltd. 50% by mass 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". Manufactured by Sunapro Co., Ltd. 50% by mass 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 glass transition temperature measurement method described above. The results of the glass transition temperature (Tg) measurements are shown in Table 1.

[0124] <Evaluation: Tackiness of the protective layer at room temperature (before UV irradiation treatment)> The adhesion strength of each protective layer to the silicon wafer was measured as follows, and the tackiness of the protective layers at room temperature was evaluated. First, backing tape was attached to each protective layer, and then cut to prepare 10 mm wide test samples. The protective layers of the prepared test samples were bonded to a silicon bare wafer at 23°C. Using a tensile testing machine, one end of the sheet-like test sample in the longitudinal direction was gripped with a chuck, and a 180-degree 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 the protective layer (before and after UV irradiation treatment)> The adhesion strength of each protective layer to the silicon wafer was measured as follows, and the adhesion strength of the protective layers to the silicon wafer was evaluated. In detail, a 180-degree peel test was performed in the same manner as the tackiness evaluation method described above, except that the protective layer of the prepared test sample was bonded to a silicon bare wafer at 70°C. Furthermore, the adhesive strength after irradiation with active energy rays was measured by bonding a test sample to a silicon bare wafer at 70°C and irradiating it with ultraviolet light from the backing tape side (1 J / cm²). 2 After that, measurements were taken in the same manner as described above.

[0126] <Evaluation: Removability of protective layer (water solubility) (after UV irradiation)> Each protective layer was bonded to a 6-inch diameter silicon bare wafer at 70°C, and then the silicon bare wafer was bonded to a dicing tape. The test sample prepared in this way was then bonded to a dicing ring. For the protective layer, apply 0.5 or 1.0 [J / cm²] of high-pressure mercury lamp. 2 The protective layer was treated with a light irradiation process (including ultraviolet light) to enhance its hydrophilicity. Subsequently, to remove the protective layer, a cleaning unit manufactured by DISCO (product name DFD6361) was used to spray 25°C water onto the silicon bare wafer while rotating a disc-shaped stage that supported the dicing tape from below in the circumferential direction. The stage rotation speed was set to 1500 rpm, and the water spraying time was set to 180 seconds. Next, we evaluated whether the protective layer had peeled off and been removed from the substrate (bare silicon wafer). The following evaluation criteria were followed. (Excellent) ○ The protective layer has been completely removed. (Good) △ Most of the protective layer was removed, but some remained (remaining was confirmed in less than 10% of the total area). (Defective) × The protective layer was not removed at all, or most of it remained (remaining was confirmed in an area exceeding 10% of the total area).

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

[0128] By implementing the semiconductor device manufacturing method described in the above embodiment, it is possible to efficiently manufacture semiconductor devices in which multiple semiconductor chips with virtually no foreign matter attached are stacked. [Industrial applicability]

[0129] The method for manufacturing electronic component devices of the present invention is suitably used, for example, to manufacture semiconductor devices having semiconductor integrated circuits. [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: Diebond sheet, G: Glass carrier, W: Semiconductor wafer, X: Semiconductor chip, V: Through-hole via, D: Electrode section B: Backgrind tape.

Claims

1. When manufacturing electronic component devices, the protective layer is provided on the substrate to protect the target surface, and is then removable with a water-containing liquid. The protective layer comprises a polymer having a glass transition temperature of 10°C to 50°C. The protective layer, when bonded to a silicon wafer at 23°C, has an adhesive strength of 0.5 N / 10 mm or less before being irradiated with active energy rays. The protective layer is a protective sheet that, when bonded to a silicon wafer at 70°C, has an adhesive strength of 1.0 N / 10 mm or more before being irradiated with active energy rays.

2. The protective layer, when bonded to the silicon wafer at 70°C, is subjected to irradiation with an active energy ray of 1 J / cm using a high-pressure mercury lamp. ２ 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 irradiated.

3. The protective layer further contains a compound that generates acid upon irradiation with active energy rays, The protective sheet according to claim 1 or 2, wherein the polymer has an ester group in its molecule that is hydrolyzed by the acid to produce a hydrophilic group.

4. The protective sheet according to claim 3, wherein the polymer has constituent units of a (meth)acrylic acid ester monomer in its molecule that generate a carboxyl group as the hydrophilic group by the acid.

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