TW202408808A - Protective sheet - Google Patents

Abstract

Provided is a protective sheet including a protective layer to be removed by a liquid including water after being used for protecting at least a part of a surface of an object to be protected, in which the protective layer includes a hydrophilic polymer in a solid state, and a liquid compound including a hydrophilic group in its molecule.

Description

Protective sheet

The present invention relates to a protective sheet used for manufacturing electronic components such as semiconductor integrated circuits.

Conventionally, a protective sheet used to protect at least a part of the surface of an object to be protected, for example, in manufacturing a semiconductor device has been known. The object to be protected by such a protective sheet is, for example, a substrate such as a semiconductor wafer. This type of protective sheet is used in the manufacturing process of semiconductor devices by being attached to at least part of the surface of an object to be protected.

Generally speaking, the method of manufacturing a semiconductor device includes: a first step of forming a circuit surface on one side of a disc-shaped bare wafer by using highly integrated electronic circuits; and a second step of forming a circuit surface from the semiconductor wafer. Semiconductor wafers are round-cut and assembled. In the latter step, in addition to using a dicing tape having a base material layer and an adhesive layer, and an adhesive wafer laminated on the dicing tape and attached to the semiconductor wafer, for example, the above-mentioned protective sheet is used.

Specifically, the final steps include: The protection step is to protect the circuit surface of the disc-shaped semiconductor wafer by covering it with the protective sheet as mentioned above; The mounting step is to overlap the surface of the semiconductor wafer (the surface without circuit components) on the die-sticking chip on the dicing belt, and fix the semiconductor wafer to the dicing belt through the chip-sticking chip; The wafer cutting step is to obtain multiple semiconductor wafers (die) by dividing the semiconductor wafer and the die bonding wafer into small pieces; The expansion step is to stretch the cutting belt toward the radiation direction of the semiconductor wafer to expand the distance between adjacent semiconductor wafers (die); The pick-up step is to peel between the small die bonding wafer and the dicing belt, and take out the semiconductor wafer in the state with the small die bonding wafer attached; The die bonding step is to bond the semiconductor chip with the die bonding chip attached to the object to be bonded through the die bonding die; and The hardening step is to perform thermal hardening treatment on the small chip bonded wafer adhered to the adherend. Semiconductor devices are manufactured through steps such as these.

As the above-mentioned protective sheet, for example, a protective sheet is known, which is removed after being attached to the protected surface in order to prevent the deposited product from adhering to the surface (protected surface) of the semiconductor wafer, etc. in a film forming step by evaporation, etc. (for example, Patent Document 1).

The protective sheet described in Patent Document 1 has a resin composition containing an oxyalkylene group-containing polyvinyl alcohol-based resin with a saponification degree of 55 mol% or less. The resin composition of the protective sheet described in Patent Document 1 is water-soluble and can be easily removed by relatively low-temperature water after protecting a portion of the surface of a substrate such as a semiconductor wafer. In addition, since the resin composition of the protective sheet described in Patent Document 1 contains the above-mentioned polyvinyl alcohol-based resin, it can adhere appropriately to the surface to be protected. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2021-161735

[The technical problem that the invention is intended to solve]

However, the resin composition of the protective sheet described in Patent Document 1 can be appropriately adhered to the protected object, but because it only contains polyvinyl alcohol-based resins and additives, etc., there is a problem that the processability is not necessarily good. Specifically, when the resin composition formed into a sheet is cut into a protective layer of a desired size, there is a problem that the processability is not necessarily good, such as micro cracks are easily generated in the portion of the protective layer subjected to the cutting force. In this way, the protective layer formed by the resin composition of the protective sheet described in Patent Document 1 can be easily removed by a water-containing liquid and has appropriate adhesion to the protected object, but the processability is not necessarily good.

In contrast, it is difficult to say that sufficient research has been conducted on protective sheets having a protective layer that can be easily removed by a water-containing liquid and has good adhesion to the object to be protected and good processability.

Therefore, the subject of the present invention is to provide a protective sheet material having a protective layer that can be easily removed by a water-containing liquid and has good adhesion to the protected object, and the processability of the protective layer is also good. [Technical means]

In order to solve the above problems, the protective sheet of the present invention is provided with a protective layer that is removed by a water-containing liquid after protecting at least a part of the surface of the object to be protected; and The aforementioned protective layer contains a solid hydrophilic polymer and a liquid compound containing a hydrophilic group in the molecule.

Hereinafter, the embodiment of the protective sheet of the present invention will be described with reference to the drawings. In addition, since each figure in the drawings is a schematic diagram, the length-to-width ratio of each figure and the actual object is not necessarily the same.

The protective sheet 1 of this embodiment, as shown in Figure 1, is provided with a protective layer 11. The protective layer 11 protects at least a part of the surface of the object to be protected, and when it comes into contact with a water-containing liquid, at least part of it will dissolve. Surface removal of protected objects. In addition, the aforementioned protective layer 11 contains a solid hydrophilic polymer and a liquid compound containing a hydrophilic group in the molecule. According to this structure, the protective layer 11 of the protective sheet 1 of this embodiment can be removed relatively easily by a water-containing liquid, and not only has good adhesion to the object to be protected, but also has good processability.

[Release paper to protect sheet] The protective sheet 1 , for example, as shown in FIG. 1 , may also include two release papers 15 arranged to sandwich the protective layer 11 . The surface of the release paper 15 that is in contact with the protective layer 11 can also be released.

The release paper 15 may also be a resin film, for example. Examples of the resin film include polyethylene terephthalate resin films, polyethylene films, polypropylene films, and the like.

[Protective layer of protective sheet] The protective layer 11 is, for example, used to temporarily protect the protected surface (hereinafter also referred to as the protected surface) of the object to be protected. By stacking the protective layer 11 on the protected surface until the protective layer 11 stacked on the protected surface is removed, foreign matter can be prevented from adhering to the protected surface.

Examples of objects to be protected include substrates constituting electronic component devices such as semiconductor devices. Examples of the substrate include circuit substrates such as semiconductor wafer W.

The protective layer 11, for example, can prevent foreign matter such as broken pieces that may be generated during the dicing from adhering to the protected surface (electrical surface) of the substrate (semiconductor wafer) when the protected surface (electrical surface) is diced together with the substrate (semiconductor wafer), thereby protecting the protected surface (electrical surface).

The above-mentioned protective layer 11 has flexibility and can be deformed with relatively weak force. In addition, the above-mentioned protective layer 11 has, for example, adhesion to the protected surface of the substrate.

The protective layer 11 may also have the property of being cut into small pieces by stretching in the plane direction. The protective layer 11 having such a property can be appropriately used in the case of manufacturing electronic component devices through the invisible processing step using the invisible crystal cutting device described later. Similarly, it can also be appropriately used in the case of manufacturing electronic component devices through the DBG process (described in detail later). In addition, the protective layer 11 may not have the above-mentioned property because it can also be appropriately used in the case of manufacturing electronic component devices through the blade crystal cutting processing step (described in detail later).

In the protective sheet 1, the thickness of the protective layer 11 is not particularly limited, for example, 1 μm or more and 100 μm or less. The thickness may be 3 μm or more, or 5 μm or more. In addition, the thickness may be 40 μm or less. When the protective layer 11 is a laminate, the thickness is the total thickness of the laminate.

In this embodiment, the hydrophilic polymer contained in the protective layer 11 is solid at room temperature. On the other hand, the liquid compound containing a hydrophilic group in the molecule contained in the protective layer 11 is liquid at room temperature. Hereinafter, the liquid compound containing a hydrophilic group in the molecule is sometimes referred to as a "liquid component".

The properties (solid or liquid) at room temperature are determined as follows. Specifically, as long as the viscosity is 200 [Pas･s] or less (200,000 [mPas･s] or less) at 25°C, it is determined to be a liquid component; if it is not liquid, it is determined to be solid. The viscosity is measured by an E-type viscometer (e.g., manufactured by Toki Sangyo Co., Ltd., product name "TV-35") at 25°C and 20rpm. In addition, when confirming the properties (solid or liquid) of each component contained in the protective layer 11, a trace amount of each compounding component can be extracted from the protective layer 11, and the molecular structure of each compounding component can be detected by, for example, infrared absorption spectroscopy (IR). If the compounding component is a polymer compound, the molecular weight of the polymer compound can be further tested by gel permeation chromatography (GPC). In addition, compounds identified by such analytical methods can be purchased separately, and the viscosity can be measured in the above manner to confirm the properties of each component (solid or liquid).

The hydrophilic polymer has a hydrophilic group in the molecule. The hydrophilic group of the hydrophilic polymer can be selected from at least one of a hydroxyl group, a carboxyl group (including a salt state), a sulfonic acid group (including a salt state), a pyrrolidone group, an amine-containing group (including a quaternary ammonium cation state), and a polyoxyethylene group. By having the hydrophilic polymer contain a hydroxyl group as a hydrophilic group in the molecule, the protective layer 11 can be more fully adhered to the protected surface of the protected object.

For example, the protective layer 11 contains a hydrophilic polymer having a main chain and a plurality of side chains in the molecule as the hydrophilic polymer; the plurality of side chains each have at least one of an ester group and a hydrophilic group, and the hydrophilic group may also be a hydroxyl group or a carboxyl group.

The main chain of the hydrophilic polymer is, for example, a covalent chain generated through radical polymerization. For example, the main chain is vinyl acetate, (Meth)acrylic acid alkyl ester, (Meth)acrylic acid hydroxyalkyl ester, (Meth)acrylic acid hydroxyalkyl ester, Covalent chains generated through polymerization reactions of meth)acrylic acid or N-vinylpyrrolidone.

The plurality of side chains in the above-mentioned hydrophilic polymer each contain at least one of a hydrophilic group and an ester group. For example, among the plurality of side chains contained in the above-mentioned hydrophilic polymer, some side chains have hydrophilic groups and other side chains have ester groups. The hydrophilic group is, for example, at least one of a hydroxyl group or a carboxyl group. The ester group is represented by -C(=O)-O-. The side chain, from the main chain toward the end of the side chain, may have the atomic arrangement of the ester group of -C(=O)-O-, or may have the atomic arrangement of the ester group of -O-(C=O)-.

In each side chain containing a hydrophilic group, the hydrophilic group can be arranged at the end portion of the side chain or at the center portion of the side chain. The hydrophilic group in the side chain is preferably arranged at the end portion of the side chain. In addition, the hydrophilic group arranged at the end portion of the side chain can also be bonded to the main chain via an ester group. For example, from the main chain toward the end of the side chain, each group can be arranged in the order of ester group, alkyl group, and hydrophilic group.

In the side chain containing an ester group, the ester group is preferably arranged in the center of the side chain. In the side chain, an alkyl group having 1 to 4 carbon atoms is preferably bonded to the main chain via the ester group.

Examples of the hydrophilic polymer include polyvinyl alcohol (PVA) obtained by hydrolyzing part of the ester bond in the polymer of vinyl acetate, polyvinylpyrrolidone (PVP), polyvinylpyrrolidone (PVP) having a sulfonic acid group in the molecule, or Carboxyl water-soluble polyester polymer (PES), polyethylene oxide (PEO) (for example, molecular weight above 50,000), polyacrylic acid, or polyvinyl acetamide, etc.

The above-mentioned hydrophilic polymer is preferably water-soluble. The hydrophilic polymer is water-soluble and can be confirmed, for example, in the following manner. When the above-mentioned hydrophilic polymer film (thickness 50 μm or less) is attached to a bare silicon wafer and immersed in water at 25°C or 60°C, at least the film is completely dissolved at either temperature (no residue remains on the wafer) case), the above-mentioned hydrophilic polymer is water-soluble.

The hydrophilic polymer is preferably at least one selected from the group consisting of polyvinyl alcohol, water-soluble polyester polymers, and polyethylene oxide.

When the above-mentioned hydrophilic polymer is polyvinyl alcohol (PVA), the saponification degree (mol%) of polyvinyl alcohol may be 50 or more and 100 or less. The saponification degree of polyvinyl alcohol is preferably 55 or more, more preferably 60 or more, and even more preferably 65 or more. The higher the saponification degree of polyvinyl alcohol, the higher the hydrophilicity of the protective layer 11. Therefore, the protective layer 11 can be more easily removed by using a water-containing liquid. On the other hand, from the viewpoint of further improving the adhesion to a protected object such as a substrate, the saponification degree of polyvinyl alcohol is preferably 98 or less, more preferably 90 or less, and even more preferably 85 or less.

<Measurement method and measurement conditions of saponification degree> The saponification degree mentioned above is measured by proton magnetic resonance spectroscopy ( ¹ H MNR) implemented under the following analysis conditions. In addition, when the protective layer 11 contains components other than PVA, in order to avoid overlapping of peaks in the measurement chart, the measurement is performed after separation and extraction of PVA by methanol extraction or the like. Analytical device: FT-NMR (for example, "AVANCEIII-400" manufactured by Bruker Biospin) Observation frequency: 400MHz (1H) Measurement solvent: Heavy water, or heavy dimethylsulfoxide (heavy DMSO) Measurement Temperature: 80℃ Chemical shift standard: External standard TSP-d4 (0.00ppm) (when measuring heavy water): Measurement solvent (2.50ppm) (when measuring heavy DMSO)

<Calculation of saponification degree> The saponification degree was calculated by the following formula based on the peak of the methylene group derived from the vinyl alcohol unit (VOH) (heavy water: 2.0 to 1.1 ppm, heavy DMSO: 1.9 to 1.0 ppm) and the peak of the acetyl group derived from the vinyl acetate unit (VAc) (heavy water: around 2.1 ppm, heavy DMSO: around 2.0 ppm). In the following formula, VOH (-CH ₂ -) is the peak intensity of the methylene group derived from the vinyl alcohol unit (VOH), and VAc (CH ₃ CO-) is the peak intensity of the acetyl group derived from the vinyl acetate unit (VAc). [Figure 1]

The average degree of polymerization of the polyvinyl alcohol is preferably 100 or more, more preferably 200 or more. In addition, the average degree of polymerization is preferably 1200 or less, more preferably 1000 or less, and more preferably 800 or less. When the average degree of polymerization of the polyvinyl alcohol is 100 or more, it is easier to form the protective layer 11. That is, the processability of the protective layer 11 can be better. On the other hand, when the average degree of polymerization of the polyvinyl alcohol is 1200 or less, the hydrophilicity of the polyvinyl alcohol is higher, and the protective layer 11 is more easily dissolved in a water-containing liquid. In addition, the adhesion of the protective layer 11 to the protected object can be better.

The above-mentioned average degree of polymerization is determined by the following measurement method and measurement conditions. ＜Measurement method and measurement conditions of average degree of polymerization＞ ・Analysis device: Gel permeation chromatography analysis device (For example, made by Agilent, device name "1260Infinity") ・Pipe string: TSKgel G6000PWXL and TSKgel G3000PWXL (manufactured by Tosoh Corporation, connected in series) ・Pipe string temperature: 40℃ ・Eluent: 0.2 M sodium nitrate aqueous solution ・Flow rate: 0.8mL/min ・Injection volume: 100μL ・Detector: Differential refractometer (RI) ・Standard samples: PEG standard samples and PVA standard samples By gel permeation chromatography (GPC) measurement using a PEG standard sample, the mass average molecular weight Mw of the measured sample (PVA) and the PVA standard sample with a known average degree of polymerization were calculated. Create a calibration line based on the average degree of polymerization of the PVA standard sample and the calculated mass average molecular weight Mw of the PVA standard sample. Using this calibration curve, the average degree of polymerization of the sample to be measured (PVA) is calculated from the mass average molecular weight Mw of the sample to be measured (PVA).

The water-soluble polyester polymer (PES) mentioned above has a residue of a polycarboxylic acid and a residue of a polyol. The water-soluble polyester is, for example, a polymerization product of monomer components containing a polycarboxylic acid component and a polyol component. The water-soluble polyester polymer mentioned above may further have at least one of an anionic hydrophilic group, a cationic hydrophilic group, or a non-ionic hydrophilic group in the molecule. Examples of anionic hydrophilic groups include sulfonic acid groups (including salt states), carboxyl groups (including salt states), etc. Examples of cationic hydrophilic groups include amine-containing groups. Examples of non-ionic hydrophilic groups include polyoxyethylene groups. In addition, whether the water-soluble polyester mentioned above is water-soluble can be determined based on technical common sense.

The mass average molecular weight Mw of the water-soluble polyester polymer (PES) is preferably 40,000 (40,000) or less. When the mass average molecular weight Mw is 40,000 or less, the water-soluble polyester polymer can have a sufficiently low softening point. As a result, the adhesion of the protective layer 11 to the substrate (semiconductor wafer, etc.) can be improved. In addition, the protective layer 11 can be more easily removed from the surface of the protected object by a water-containing liquid.

The above-mentioned polyethylene oxide (PEO) has a polyoxyethylene group as a hydrophilic group in the molecule. The mass average molecular weight Mw of the polyethylene oxide (PEO) is preferably 1,000,000 (one million) or less. By having the mass average molecular weight Mw below 1,000,000, the above-mentioned polyethylene oxide (PEO) can have a sufficiently low softening point. Thereby, the adhesion of the protective layer 11 to the substrate (semiconductor wafer, etc.) can be better. In addition, the protective layer 11 can be removed from the surface of the protected object in a shorter time and efficiently by using aqueous liquid.

The above-mentioned polyacrylic acid has a carboxyl group as a hydrophilic group in the molecule. The above-mentioned polyacrylic acid is a polymer obtained by polymerizing acrylic acid monomers or methacrylic acid monomers. In the above-mentioned polyacrylic acid, the total of the constituent units of acrylic acid monomers or methacrylic acid monomers accounts for more than 90% by mass of the total constituent units. The molecular weight of the above-mentioned polyacrylic acid may also be, for example, more than 1,000 and less than 5,000,000. In addition, the above-mentioned polyacrylic acid may also be in a salt state such as a sodium salt, a potassium salt, or an ammonium salt. In other words, the above-mentioned expression "polyacrylic acid" includes polyacrylic acid salts such as sodium polyacrylate.

The above-mentioned polyvinyl acetamide has an amine-containing group as a hydrophilic group in the molecule. Specifically, the amine-containing group is represented by (-NH-CO-). The above-mentioned polyvinyl acetamide is a polymer of N-vinyl acetamide monomer.

In this embodiment, the liquid component is a liquid compound containing a hydrophilic group in its molecule. Examples of the hydrophilic group of the liquid component include a hydroxyl group, a carboxyl group (including a salt state), a sulfonic acid group (including a salt state), a pyrrolidone group, an amine-containing group (including a quaternary ammonium cationic state), or polyoxyethylene base.

The liquid component may be a low molecular compound or a high molecular compound as long as it is liquid at room temperature (25° C.). Examples of the liquid component include polyethylene glycol that is liquid at room temperature, acrylic copolymer that is liquid at room temperature, ether-containing compounds that are liquid at room temperature, polyoxyethylene polyoxypropylene glycol that is liquid at room temperature, polycationic polymers that are liquid at room temperature, monomers containing hydrophilic groups that are liquid at room temperature, silane coupling agents that are liquid at room temperature, surfactants that are liquid at room temperature, and high boiling point compounds that are liquid at room temperature.

Examples of liquid polyethylene glycol at room temperature include polyethylene glycol having an average molecular weight of 600 or less. For example, because the melting point of polyethylene glycol (PEG600) with an average molecular weight of 600 is between 17°C and 22°C, PEG600 is liquid at room temperature (25°C). In addition, polyethylene glycol with an average molecular weight of 600 or less is water-soluble.

An acrylic copolymer that is liquid at room temperature, for example, has at least a carboxyl group as a hydrophilic group, and has at least a structural unit of a (meth)acrylic acid alkyl ester monomer and a carboxyl group-containing (meth)acrylic acid monomer in the molecule. Component unit. The mass average molecular weight of the acrylic copolymer is, for example, 10,000 or less (for example, about 2,000), and the acid value is about 70 [mgKOH/g]. Examples of products containing the acrylic copolymer include product name "ARUFON 3510" (manufactured by Toagosei Co., Ltd.). In addition, the acrylic copolymer is water-soluble. In addition, the acrylic copolymer that is liquid at room temperature is, for example, an acrylic water-soluble graft polymer having a hydrophilic group (polyoxyethylene chain) in the side chain. The mass average molecular weight of the acrylic copolymer is, for example, about 70,000, and the glass transition point Tg is about -40°C. Examples of products containing the acrylic copolymer include the product name "MARPROOF HP Series" (manufactured by NOF Corporation).

Ether-containing compounds that are liquid at room temperature have a polar part and a non-polar part in the molecule. Examples of products containing the ether-containing compound include product name "SOFBAR P series" (manufactured by NOF Corporation).

Polyoxyethylene polyoxypropylene glycol, which is liquid at room temperature, is a block copolymer having a polyoxyethylene structure and a polyoxypropylene structure in the molecule. Examples of products containing polyoxyethylene polyoxypropylene glycol, which is liquid at room temperature, include the product "Epan Series" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

The polycationic polymer that is liquid at room temperature is obtained, for example, by polymerizing at least an allyl amine (diallylamine), and therefore has an amine-containing ring structure in the side chain portion. The amine in the side chain portion may be, for example, a diamine, a tertiary amine, or a quaternary ammonium salt. The polycationic polymer may also have, for example, a sulfonic acid group in the main chain. Products containing the polycationic polymer include, for example, the product name "PAS series" (manufactured by Nittobo Medical Co., Ltd.). The polycationic polymer that is liquid at room temperature is, for example, represented by the following general formula (1). In the general formula (1), x is a diamine, a tertiary amine, or a quaternary ammonium salt. m may be 0. n is an integer greater than 1, and may also be, for example, less than 1000. [Chemistry 1]

Examples of monomers containing a hydrophilic group that are liquid at room temperature include (meth)acrylic acid type monomers having a (meth)acrylic acid structure or a (meth)acrylic acid ester structure in the molecule. The (meth)acrylic acid type monomer contains a carboxyl group or an ester bond (ester group) as a hydrophilic group in the molecule. Such (meth)acrylic acid type monomers are commercially available (e.g., "Light Ester" series and "Light Acrylate" series manufactured by Kyoeisha Chemical Co., Ltd.).

Silane coupling agents that are liquid at room temperature have an alkoxysilane structure as a hydrophilic group in the molecule. As the above-mentioned silane coupling agents, there can be listed silane coupling agents containing a vinyl group, an epoxy group, a styrene group, a (meth) acrylic group, an amine group, an isocyanate group, or an acid anhydride in the molecule. In addition, when the above-mentioned silane coupling agents are classified according to the functional group bonded to silane (Si), trialkoxysilane type, methyldialkoxysilane type, etc. can be listed. The alkoxy group can be a methoxy group or an ethoxy group. As such silane coupling agents, products such as the "KBM series" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

Surfactants that are liquid at room temperature contain anionic hydrophilic groups, cationic hydrophilic groups, or nonionic hydrophilic groups (polyoxyethylene chains, etc.) as hydrophilic groups in their molecules. When the surfactant that is liquid at room temperature is a polymer compound, the hydrophilic group may also be an acrylonitrile group, an ester bond, etc. The chemical name of the surfactant that is liquid at room temperature and the products containing the surfactant are explained below.

The above-mentioned liquid surfactant is, for example, an alkyl trimethyl type or an alkyl dimethyl benzyl type quaternary ammonium salt type cationic active agent. The alkyl moiety is, for example, lauryl, palmityl, stearyl, or behenyl. This liquid surfactant is contained in, for example, the product name "NISSANCATION" series (manufactured by NOF Corporation). In addition, the above-mentioned liquid surfactant is, for example, an acetate salt of an aliphatic amine (laurylamine or stearylamine). This surfactant is contained in, for example, the product name "NISSANCATION" series (manufactured by NOF Corporation).

The liquid surfactant is, for example, polyoxyethylene lauryl ether sulfate sodium salt. The surfactant is, for example, contained in the product "TRAX" series (manufactured by NOF Corporation).

The liquid surfactant is, for example, sodium salt of fatty acid amide ether sulfate. The surfactant is, for example, contained in the product "SUNAMIDE" series (manufactured by NOF Corporation).

The above-mentioned liquid surfactant is, for example, fatty acid sodium methyltaurate. This surfactant is contained in, for example, the product name "DIAPON" series (manufactured by NOF Corporation).

The liquid surfactant is, for example, polyoxyethylene branched alkyl ether or other polyoxyalkylene alkyl ether. The surfactant is, for example, contained in the product name "DISPANOL" series (manufactured by NOF Corporation).

The above-mentioned liquid surfactants are glycolic acid betaine-type amphoteric interface active agents such as aliphatic alkyl dimethyl-glycolic acid betaine or fatty acid-acylaminopropyl dimethyl-glycolic acid betaine. agent. This surfactant is contained in, for example, the product name "NISSAN ANON" series (manufactured by NOF Corporation).

The liquid surfactant is, for example, polyoxyethylene alkylamine. The surfactant is, for example, contained in the product "NYMEEN" series (manufactured by NOF Corporation).

High-boiling compounds that are liquid at room temperature are, for example, organic compounds with a boiling point of 100° C. or higher. In addition, the boiling point of the compound may be less than 250°C. The molecular weight of the high-boiling compound that is liquid at room temperature is, for example, 200 or less, preferably 150 or less. Examples of high-boiling compounds that are liquid at room temperature include monohydric alcohols such as butanol and isobutanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and glycerol; propyl acetate, isoacetate Esters such as butyl ester, butyl acetate or ethyl lactate; ketones such as methyl isobutyl ketone (MIBK) or cyclohexanone; ethylene glycol monomethyl ether, diethylene glycol monoethyl ether or 1-methoxy Glycol monoethers such as 2-propanol; glycol diethers such as ethylene glycol dimethyl ether or diglyme; N,N-dimethylformamide (DMF) or N- Nitrogen-containing organic compounds such as methyl-2-pyrrolidone (NMP). As a high boiling point compound that is liquid at room temperature, diethylene glycol, glycerol, N-methyl-2-pyrrolidone, etc. are ideally used.

The liquid component is preferably water-soluble. A compound having a solubility of 1 g or more in 100 g of water at 25°C is considered to be water-soluble. Since the liquid component is water-soluble, the protective layer 11 can be removed more easily by a liquid containing water.

The above liquid components are ideally non-volatile compounds regardless of their molecular structure. Compounds with a vapor pressure of 2.5 hPa or less at 20°C are considered non-volatile.

The protective layer 11 may have a hydrophilicity greater than or equal to a predetermined value when removed by a liquid containing water. When the protective layer 11 has a hydrophilicity greater than or equal to a predetermined value, at least a portion of the protective layer 11 is usually dissolved in the liquid containing water.

The water absorption rate of the protective layer 11 is preferably 2.0 mass % or more when it is removed by a water-containing liquid. In this way, the protective layer 11 is more easily dissolved in the water-containing liquid. The above water absorption rate can be increased by, for example, increasing the content ratio of the hydrophilic group in the hydrophilic polymer or increasing the content of the liquid component in the protective layer 11. The water absorption rate of the protective layer 11 can also be, for example, 10.0 mass % or less.

The water absorption rate of the protective layer 11 is obtained by measuring the value of the potentiometric titration method using the Karl Fischer titration method. Specifically, the test sample in a stable state in an environment of a temperature of 23°C and a humidity of 50RH% is heated at 150°C for 3 minutes by a water vaporization device, and the vaporized water is measured at the same time. The water absorption rate is obtained by the ratio of the measured water content to the mass of the test sample after heating.

In the protective layer 11, the amount of the liquid component is preferably 1 part by mass or more, and more preferably 2 parts by mass or more relative to 100 parts by mass of the hydrophilic polymer. Thereby, the protective layer 11 has good workability in that it is less likely to cause micro cracks when receiving a cutting force during cutting, and can more fully adhere to the object to be protected. Moreover, the amount of the liquid component may be 60 parts by mass or less or less than 40 parts by mass relative to 100 parts by mass of the hydrophilic polymer. Since the protective layer 11 does not contain excessive liquid components, the formability when producing the protective layer 11 is better.

In this embodiment, the adhesion of the protective layer 11 to the object to be protected is represented by the peeling force when the protective layer 11 is peeled off from a bare silicon wafer as a substrate. The peeling force of the protective layer 11 may be 100 [N/100mm] or less. It may also be 80 [N/100mm] or less. Furthermore, the peeling force may also be 0.2 [N/100mm] or more.

The above-mentioned peeling force is measured under the following measurement conditions. In order to measure the peeling force of one side of the protective layer 11 (the side attached to the bare silicon wafer), a measurement sample was prepared as follows. First, a backing tape is attached to the surface opposite to the above-mentioned surface of the protective layer 11 using a hand pressure roller at 25°C. Next, the measurement sample was processed to have a width of 100 mm, and the bare wafer was bonded to the above surface of the protective layer 11 . Lamination is carried out under the conditions of 90℃ and 10mm/ses. Next, in an environment of 23° C., the protective layer 11 together with the substrate tape was peeled off from the bare wafer at a peeling angle of 180° and a peeling speed of 300 mm/min, and the peeling force was measured. In addition, as the measuring device, for example, "Precision Universal Testing Machine (Autograph) (manufactured by SHIMADZU Corporation)" can be used.

When the dynamic viscoelasticity of the protective layer 11 is measured, the storage elastic modulus E' of the protective layer at 70°C may be less than 0.1 GPa (less than 100 MPa). Since the storage elastic modulus E' is appropriately low, the protective layer 11 may have better tracking properties when subjected to deformation force. In addition, since the wettability at the interface of the protected object is better, the adhesion to the protected object may be better. Furthermore, the storage elastic modulus E' of the protective layer 11 at 70°C may also be greater than 0.01 GPa (greater than 10 MPa).

When measuring the dynamic viscoelasticity of the above-mentioned protective layer 11, the temperature at which the loss elastic modulus E" reaches the maximum value can be below 35°C. This allows the protective layer 11 and the object to be protected to be fully adhered to each other at a lower temperature. Close adhesion. In addition, the temperature at which the loss elastic modulus E" reaches the maximum value can also be above 5°C.

When measuring the dynamic viscoelasticity of the protective layer 11, the peak temperature of the ratio of the loss elastic modulus E" to the storage elastic modulus E', Tanδ (E"/E'), is ideally less than 70°C. Thus, the protective layer 11 can have better tracking properties when subjected to deformation force. In addition, since the wettability of the interface with the protected object is better, the adhesion to the protected object can be better. In addition, since the protective layer 11 can be closely attached to the protected object at a lower temperature, the protective step described later can be implemented at a lower temperature, thereby further reducing the thermal energy cost required for heating in the protective step. Furthermore, the peak temperature of the above-mentioned Tanδ (E”/E’) can be above 25°C or above 30°C. The higher the above-mentioned peak temperature, the easier it is to process the protective layer 11.

The dynamic viscoelasticity measurement of the above-mentioned protective layer 11 was carried out in the tensile mode using a solid viscoelasticity measuring device under the following test conditions. Thickness of test sample: 50μm; Width of test sample: 10mm; Distance between chucks: 20mm; Heating rate: 10℃/min; Test temperature: 0℃～120℃; Frequency: 1Hz The storage elastic modulus E’ and the loss elastic modulus E” are measured over time, and the Tanδ over time is calculated by the formula Tanδ=E”/E’. The higher the Tanδ, the higher the viscosity properties. Plot Tanδ as a peak shape and read the temperature when it reaches the top of the peak. In addition, as the storage elastic modulus E' and the peak value of Tanδ at 70°C, the average value of three measurements was used.

The protective sheet 1 can be manufactured by a general method. For example, the protective layer 11 can also be manufactured by mixing the hydrophilic polymer, liquid component, and solvent by a general method, applying the mixture on a release paper 15, and then allowing the solvent to evaporate from the mixture.

The protective sheet 1 is used by, for example, peeling off the release paper 15 from the protective layer 11 and attaching the protective layer 11 to the protected surface of the object to be protected. Then, the protective layer 11 in the state of protecting the protected surface is removed from the protected surface by a water-containing liquid.

Next, the method of using the protective sheet 1 of this embodiment will be described. Specifically, the method of manufacturing an electronic component device using the protective sheet 1 will be described as an example. In this example, the object to be protected is a substrate constituting a component of the electronic component device.

The electronic component device manufactured using the above protective sheet 1 may be, for example, a semiconductor device such as a semiconductor integrated circuit including a semiconductor chip, a device including a system LSI with complementary MOS (CMOS), or a device using a micron Processing technology is a device that integrates mechanical components, sensors, actuators, or electronic circuits on a silicon substrate, glass substrate, or organic material substrate (MEMS, Micro Electro Mechanical Systems, Micro Electro Mechanical Systems) Devices such as this. The manufactured electronic component device may also be a device equipped with a wiring substrate.

In the manufacturing method of the electronic component device using the above-mentioned protective sheet 1, as shown in FIG. 2B, the protected surface Sa of one side of the substrate S is protected by the protective layer 11. In addition, the protected surface Sa may be provided with circuit components (described in detail later) or may not be provided. In other words, the protected surface Sa of the substrate S may be, for example, an electrical surface on which a circuit is formed, or may be a non-electrical surface on which no circuit is formed.

The protective layer 11 may also be formed on the protected surface Sa of the substrate S. For example, it may be formed by applying a mixture of the above-mentioned hydrophilic polymer, liquid component, and solvent to the protected surface Sa of the substrate S and then allowing the solvent to evaporate. The formed protective layer 11 has good adhesion to the protected surface Sa of the substrate S because it contains the above-mentioned hydrophilic polymer and liquid component.

The material of the substrate S is not particularly limited as long as it is plate-shaped. Examples of the substrate include substrates constituting semiconductor wafers, sensor wafers such as CMOS and MEMS, dummy wafers, and wiring substrates.

The manufacturing method of an electronic component device using the above protective sheet 1 includes: The step of protecting the protected surface by overlapping the protective layer 11 of the above-mentioned protective sheet 1 with the protected surface on one side of the substrate (protection step); and A step of removing by bringing the protective layer 11 laminated on the protected surface into contact with a water-containing liquid (removing step). The details of the protective layer 11 are as described above.

In the above-mentioned manufacturing method of an electronic component device, if necessary, a step of increasing the humidity of the gas in contact with the protected surface Sa of the substrate S (wetting step) may be performed before the protection step (see FIG. 2A ). By performing the wetting step, the adhesion of the protective layer 11 to the protected surface Sa can be improved. The wetting step can be implemented by, for example, bringing a gas containing water vapor into contact with the protected surface, spraying mist water on the protected surface, or applying water to the protected surface.

In the above protection step, the protective layer 11 of the protective sheet 1 is laminated on the protected surface Sa of the substrate S. In the protection step, for example, the protective layer 11 is overlapped on the surface of the substrate S on the side where at least one of the circuit wiring, the sensor portion, and the electrode portion as circuit components is arranged. In the above protection step, it is ideal to overlap the protective layer 11 on at least one side of the substrate S in such a manner that the circuit wiring, the sensor portion, or the electrode portion are covered with the protective layer 11 . Examples of circuit components include circuit wiring, electrode portions, transistors, diodes, and sensor portions (light-receiving sensors, vibration sensors, etc.).

In the above-mentioned manufacturing method of the electronic component device, if necessary, for example, as shown in FIG. 2C , the laminate of the stacked substrate S and the protective layer 11 can be divided into small pieces so as to leave gaps in the plane direction. The step of stacking the wafer S' of the substrate into wafers and the wafers 11' of the protective layer to form a plurality of wafers of the laminate (for example, the dicing step).

In the removal step, as shown in FIG. 2D , the protective layer 11 stacked on the protected surface of the substrate S is removed using a water-containing liquid. In the removal step, when the protective layer 11 is removed, the protective layer 11 may be completely dissolved in the water-containing liquid, or may be partially dissolved in the water-containing liquid.

Hereinafter, a manufacturing method of a semiconductor device for manufacturing a semiconductor integrated circuit is cited as a specific example, and the manufacturing method is described in detail with reference to the drawings.

In a method of manufacturing a semiconductor device (electronic component device), for example, a semiconductor wafer X is cut out from a semiconductor wafer W having a circuit surface formed thereon, and a semiconductor device having the cut-out semiconductor wafer X is assembled. In the method of manufacturing a semiconductor device described below, a semiconductor device is manufactured using at least the protective layer 11 of the protective sheet 1 and the dicing tape 20 (see FIG. 3A ). The dicing belt 20 has a base material layer 21 and an adhesive layer 22 . These sheets and tapes are used as auxiliary tools for manufacturing semiconductor devices. Alternatively, the die bonding film 50 with the die bonding chip 30 overlapping the adhesive layer 22 of the die cutting belt 20 may be used (see FIG. 3B ). As the die tape 20 and the die adhesion film 50, commercially available products can be used respectively.

Generally speaking, the manufacturing method of a semiconductor device includes the following steps: forming a circuit surface on one side of a bare wafer by using highly integrated electronic circuits; and a subsequent step of cutting out semiconductors from the semiconductor wafer W with the circuit surface formed. Wafer X and assemble.

In the subsequent step, for example, the wafer (semiconductor wafer W) serving as the substrate on which the circuit surface is formed is diced into smaller semiconductor wafers X (die). Thereafter, a semiconductor integrated circuit (semiconductor device) is assembled by bonding the small semiconductor wafer X to a bonded body or the like.

Hereinafter, specific examples of the manufacturing method of the semiconductor device will be described in detail from the first example to the third example. In addition, in the drawing showing the manufacturing method of the first example, it is described as "I". Similarly, the second example and the third example are respectively described as "II" and "III" in the drawings.

"First Example of Manufacturing Method of Semiconductor Device" The manufacturing method of a semiconductor device in the first example includes an assembly step of cutting out a semiconductor wafer X from a semiconductor wafer W (substrate) on which a circuit surface is formed, and assembling a semiconductor device having the semiconductor wafer X. This assembly step at least includes: on a circuit surface that is at least one side of the semiconductor wafer W and on which any circuit component is formed, a protective layer 11 for protecting the circuit component is laminated to protect the circuit surface (protected surface). ) protection steps; The semiconductor wafer W with circuit components formed on one side is attached to the die attach film 50 (the die attach chip 30 stacked on the die tape 20 ), and the semiconductor wafer W is fixed to the die attach film 50 . steps; If necessary, perform a peeling step of removing the release paper 15 by peeling between the protective layer 11 and the release paper 15; By dicing the laminated product of the semiconductor wafer W, the protective layer 11, and the die bonding wafer 30 into pieces at intervals in the plane direction, a semiconductor wafer and the steps of laminating the plurality of small pieces of the laminate formed by stacking the small pieces 30' of the chip 30; The removal step of removing each small piece 11' of the protective layer by bringing each small piece 11' of the protective layer stacked on the circuit surface of the semiconductor chip X into contact with a water-containing liquid; The step of picking up the semiconductor wafer X in the state of peeling off the die cutting belt 20 and the chip-adhesive chip 30', and taking out the semiconductor chip X with the chip-adhesive chip 30' attached; and A bonding step of bonding the taken-out semiconductor wafer When performing these steps, the above-mentioned protective layer 11 and the die-cutting die-bonding film 50 with the die-cutting belt 20 are used as manufacturing auxiliary tools.

In the manufacturing method of the first example, a blade dicing process is performed as a step of manufacturing a plurality of small pieces of the above-mentioned laminate. In the blade dicing process, the adhesive wafer 30, the semiconductor wafer W, and the protective layer 11 are diced by a dicing blade T or the like to manufacture semiconductor wafers X (die) obtained by dicing the semiconductor wafer W.

The semiconductor wafer W is configured so as to obtain a plurality of semiconductor chips X. Specifically, the semiconductor wafer W is configured so as to be divided into small pieces by leaving spaces along a plurality of directions along the surface (e.g., directions along the surface direction and orthogonal to each other), thereby manufacturing a plurality of semiconductor chips X. In addition, the semiconductor wafer W has a circuit surface on one side of which at least one circuit component is arranged.

In the semiconductor industry in recent years, with the further development of integration technology, there is a need for a thinner semiconductor wafer (for example, a thickness of more than 20 μm and less than 50 μm). The shape of the semiconductor wafer when viewed from one side in the thickness direction is, for example, a rectangular shape; the length of one side is, for example, a specified length of 5 mm to 20 mm.

In the protection step, as shown in FIG. 4A , a protection layer 11 is stacked on the surface of the semiconductor wafer W. By stacking the protection layer 11 on the surface of the semiconductor wafer W, the surface of the semiconductor wafer W can be protected by the protection layer 11 until the protection layer 11 is removed. Therefore, it is possible to prevent garbage and the like from being attached to the surface of the semiconductor wafer W covered by the protection layer 11. For example, the protection step and the installation step can be performed simultaneously in the following manner.

In the installation step, first, after the dicing ring R is installed on the adhesive layer 22 of the dicing belt 20, the dicing ring R can be fixed on the holder H of the expansion device. Afterwards, as shown in FIG. 4A , the semiconductor wafer W, the protective layer 11 and the release paper 15 are attached to the adhesive wafer 30 stacked on the dicing belt 20 at one time. For example, the semiconductor wafer W is fixed to the die attach wafer 30 in this manner. Next, the protective layer 11 is pressed against the semiconductor wafer W through the release paper 15, thereby attaching the protective layer 11 to the circuit surface.

When the release paper 15 is used as described above, a peeling step of removing the release paper 15 by peeling the release paper 15 from the protective layer 11 may also be performed.

In the blade dicing process, for example, as shown in FIG. 4B and FIG. 4C , the semiconductor wafer W is diced. Specifically, the protective layer 11 and the semiconductor wafer W are cut into a specified size together with the adhesive chip 30 to form a semiconductor chip X with a small piece 30' of the attached chip. At this time, a small piece 11' of the protective layer is also formed. The blade dicing process is performed, for example, using a dicing blade T in accordance with a conventional method. In the blade dicing process, for example, a cutting method called full cutting can be adopted in which the semiconductor wafer W is cut into the adhesive chip 30. There is no particular limitation on the dicing device used in the blade dicing process, and a conventionally known device can be used. In the blade dicing process, foreign matter such as debris may be generated along with the cutting of the semiconductor wafer W. At this time, since the protected surface of the semiconductor wafer W is protected by the protective layer 11, foreign matter can be prevented from adhering to the protected surface.

In the removal step, for example, as shown in FIG. 4D , the plurality of small pieces 11’ of the protective layer are brought into contact with a water-containing liquid, and at least a portion of each small piece 11’ is dissolved in the above-mentioned liquid, thereby removing each small piece 11’ of the protective layer from the surface (protected surface) of the semiconductor chip X. By removing the small pieces 11’ of the protective layer in this way, the plurality of small pieces 11’ of all protective layers can be removed more easily, and the amount of foreign matter attached to the surface of the semiconductor chip can be reduced more easily by the above-mentioned liquid. In addition, the surface (protected surface) of each semiconductor chip X on which the small pieces 11’ of the protective layer are superimposed can also be cleaned with a liquid.

In the removal step, the small pieces 11' of the protective layer can be removed by dissolving all the small pieces of the protective layer (the plurality of small pieces 11' of the protective layer) in the above-mentioned liquid. On the other hand, the protective layer can also be removed by dissolving a part of the components of the small pieces 11' of the protective layer in the above-mentioned liquid and peeling each small piece 11' whose adhesion to the semiconductor wafer X is weakened from the semiconductor wafer X. A plurality of small pieces 11'.

The water-containing liquid is not particularly limited as long as it is a liquid substance containing water. The liquid may contain 30 mass% or more, 50 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more. In addition to water, the above-mentioned liquid may also contain components dissolved in water. Examples of this component include water-soluble organic solvents. Examples of the water-soluble organic solvent include monohydric alcohols having 4 or less carbon atoms, such as methanol, ethanol, or propanol such as isopropyl alcohol, or butanol such as tertiary butanol.

In the removal step of the first example, the small piece 11' of the protective layer may be immersed in the liquid being stirred so that the liquid contacts the small piece 11' of the protective layer. Alternatively, the liquid sprayed from a nozzle or the like may contact the small piece 11' of the protective layer. 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.

For example, in the removal step, the disk-shaped table supporting the wafer ribbon 20 from below is rotated in the circumferential direction, and the above-mentioned liquid is sprayed on the semiconductor wafer X of each small piece 30' attached to the wafer adhesive. In this way, the plurality of small pieces 11' of the protective layer stacked on the semiconductor wafer X can be removed.

According to the manufacturing method of the semiconductor device of the first example, since the protective layer 11 is stacked on the surface (electrical path surface) of the semiconductor wafer W on which the circuit components are formed, the above-mentioned electric path surface can be protected until the protective layer 11 is removed.

In the picking step, as shown in FIG. 4E , the small piece 30 ′ of the wafer bonded with the semiconductor wafer X is peeled off from the adhesive layer 22 of the wafer cutting tape 20. Specifically, the pin member P is raised and the semiconductor wafer X to be picked up is pushed up through the wafer cutting tape 20. The pushed-up semiconductor wafer X and the small piece 30 ′ of the wafer bonded with the semiconductor wafer X are held by the adsorption jig J.

When the pick-up step is performed in this way, the die-adhesive chip 30' attached to the semiconductor wafer X needs to be easily peeled off from the adhesive layer 22 of the dicing belt 20. The above-mentioned cutting belt 20 is designed to perform such performance well. For example, the dicing belt 20 is configured so that by irradiating active energy rays (such as ultraviolet rays), the adhesive layer 22 is hardened and the adhesive force of the adhesive layer 22 is reduced. By hardening the adhesive layer 22 after irradiation, the adhesive force of the adhesive layer 22 can be reduced, so that the semiconductor wafer X and the chip-adhering chip 30' can be peeled off from the adhesive layer 22 more easily after irradiation. The crystal cutting belt 20 constructed in this way is already commercially available.

In the bonding step, the semiconductor chip X with the chip 30' attached thereto is bonded to the connected body Z. In other words, the semiconductor chip X is bonded to the connected body such as the substrate or the semiconductor chip X via the chip 30'. In addition, in the bonding step, as shown in FIG. 4F, there is a case where the semiconductor chip X with the chip 30' attached thereto is stacked multiple times. In addition, as the connected body Z, for example, an interposer, a wiring circuit substrate, or a chip of a substrate (a case where the chip of a substrate is stacked to form a layer), etc. can be cited.

In the first example, in order to protect the semiconductor chip X after the bonding step, a resin sealing step of sealing (covering) the semiconductor chip X with a thermosetting resin or the like may be performed.

Next, the second example will be described in detail. In addition, regarding the second example, the same description as the first example will not be repeated. In the second example, the same operations as in the first example can be performed unless otherwise mentioned.

"The manufacturing method of the semiconductor device in the second example" The manufacturing method of the semiconductor device in the second example is different from the first example in that the semiconductor wafer W is thinned by the so-called DBG (Dicing Before Grinding) process after the semiconductor wafer W is half-cut to make the semiconductor wafer W small. In the second example, in order to process the semiconductor wafer W into a chip (die) by cutting, a groove is formed in the semiconductor wafer W, and the semiconductor wafer W is further ground and thinned.

The manufacturing method of the semiconductor device of the second example has, for example: The half-cut processing step is to form grooves on the circuit surface of the semiconductor wafer W for dicing the semiconductor wafer W to produce a plurality of semiconductor wafers X; The back grinding step involves grinding the surface opposite to the circuit surface of the semiconductor wafer W to thin the thickness of the semiconductor wafer W; The mounting step involves attaching the thinned semiconductor wafer W to the die bonding wafer 30 on the dicing belt 20 and fixing the semiconductor wafer W to the die bonding wafer 30; The expansion step is to dice the semiconductor wafer W, the die bonding wafer 30, and the protective layer 11 together by stretching the dicing tape 20; The removal step is to remove the plurality of small pieces 11' attached to the protective layer of the semiconductor chip X; The picking step involves peeling off the semiconductor wafer X and the chip 30' to which the wafer is adhered, and taking out the semiconductor wafer X; In the bonding step, the taken-out semiconductor wafer X is bonded to the object to be bonded via the chip 30'.

In the second example, a wafer processing tape is attached to the surface of the semiconductor wafer W opposite to the protected surface, and grooves for dividing the semiconductor wafer W into small pieces are formed. The grooves are formed in the semiconductor wafer W so as not to pass through the thickness direction.

Next, for example, as shown in FIG. 5A , the back grinding tape B is laminated on the circuit surface of the semiconductor wafer W on which the trench is formed, and the back grinding tape B is used to protect the protected surface (circuit surface). Next, for example, as shown in FIG. 5B , with the back grinding tape B attached, the surface of the semiconductor wafer W where the circuit components are not arranged is polished. For example, polishing processing (back grinding processing) is performed with a polishing pad until the semiconductor wafer W reaches a specified thickness. Through the grinding process, the thickness of the semiconductor wafer W is thinned to a specified thickness.

Next, the surface of the polished semiconductor wafer W (the surface on which circuit components are not arranged) is attached to the die bonding wafer 30 on the dicing belt 20, and the mounting step is performed (see FIG. 5C).

Next, an expansion step of dicing the semiconductor wafer W and the protective layer 11 is performed. In the expansion step, as shown in FIG. 5D , in a state where the semiconductor wafer W is attached to the adhesive wafer 30 on the dicing belt 20 , the dicing belt 20 is stretched in the surface direction to change the surface area of the dicing belt 20 . big. Thereby, the laminate of the protective layer 11, the semiconductor wafer W, and the die bonding wafer 30 is divided into small pieces, and the distance between the adjacent semiconductor wafers X formed by the small pieces is expanded in the plane direction. Specifically, by pushing up the pushing member U provided in the expansion device from the lower side of the dicing belt 20, the dicing belt 20 is stretched to expand in the plane direction. Thereby, the semiconductor wafer W, the die bonding wafer 30 and the protective layer 11 are diced under specific temperature conditions. The above temperature conditions are, for example, -20°C or more and 0°C or less. By lowering the push-up member U, the expansion state is released (this is the low-temperature expansion step). When performing the expansion step at a low temperature, the protective layer 11 and the die bonding wafer 30 need to be cut and reduced into small pieces. The above-mentioned protective layer 11 and die bonding chip 30 are each designed to be well cut at this time. Furthermore, in the expansion step, the crystal cutting belt 20 can also be stretched again under a higher temperature condition (for example, 10° C. or more and 25° C. or lower) to expand the surface area of the crystal cutting belt 20 . Thereby, the adjacent semiconductor wafers

Thereafter, in the removal step, the small piece 11' attached to the protective layer of the semiconductor wafer X can be removed by the same method as the above method. In addition, by the same method as the above-mentioned method, the pickup step of taking out the semiconductor wafer X and the bonding step of bonding the semiconductor wafer X to the adherend can be performed.

In the second example, the steps not specifically mentioned can be performed in the same manner as the steps in the first example.

Furthermore, in the second example, as shown in FIG. 5E , when the semiconductor wafer W is polished using the back grinding tape B, the protective layer 11 may be disposed between the back grinding tape B and the semiconductor wafer W. Even in this state, since grinding processing (back grinding processing) can be performed, the semiconductor wafer W can be thinned to a desired thickness as shown in FIG. 5F . Thereafter, as shown in FIG. 5G , the mounting step can be performed in a state where the back grinding tape B, the protective layer 11 and the semiconductor wafer W are laminated.

Next, the third example will be described in detail. In addition, regarding the third example, the same description as the first or second example will not be repeated. In Example 3, the same operations as Example 1 or Example 2 can be performed unless otherwise mentioned.

"Method for Manufacturing Semiconductor Device of Example 3" The manufacturing method of the semiconductor device of the third example is mainly different from the first or second example in that a fragile portion is formed inside the semiconductor wafer W, and the semiconductor wafer W is divided into small semiconductor pieces using the fragile portion as a boundary. WaferX.

The manufacturing method of the semiconductor device of the third example has, for example: An installation step, which is to attach a semiconductor wafer W with circuit components formed on both sides to a wafer tape 20, and fix the semiconductor wafer W to the wafer tape 20; A protection step, which is to protect the electrical path surface by attaching a protective layer 11 to the electrical path surface of the exposed side of the semiconductor wafer W; An invisible processing step, which is to form a fragile part inside the semiconductor wafer W with the protective layer 11 attached by laser light, thereby preparing to chip the semiconductor wafer W into a semiconductor chip X (die); An expansion step, which is to chip the semiconductor wafer W and the protective layer 11 together by stretching the wafer tape 20; A removal step is to remove a plurality of small pieces 11' attached to the protective layer of the semiconductor chip X; A picking step is to peel off and take out the semiconductor chip X between the semiconductor chip X and the adhesive layer 22; and A bonding step is to bond the taken out semiconductor chip X to the attached body. When implementing these steps, the protective layer 11 and the cutting tape 20 are used as manufacturing auxiliary tools.

In the third example, as shown in FIG. 5A , the die bonding wafer 30 is not arranged on the dicing belt 20 , and the semiconductor wafer W is stacked on the adhesive layer 22 of the dicing belt 20 (see FIG. 6A ).

In the stealth processing step, fragile portions for dicing the semiconductor wafer W into semiconductor wafers X are formed inside the semiconductor wafer W. By irradiating the semiconductor wafer W with the laser light L, a fragile portion is formed inside the semiconductor wafer W (see FIGS. 6A and 6B ). The laser light L is irradiated toward the semiconductor wafer W from the dicing belt side, for example. The invisible processing step can be performed, for example, using a commercially available invisible crystal cutting device. In addition, before the mounting step, the semiconductor wafer W may be irradiated with laser light to form fragile portions inside the wafer.

In the expansion step, as shown in FIG. 6C , the diced ribbon 20 is stretched in the plane direction to expand the surface area of the diced ribbon 20, thereby dividing and fragmenting the semiconductor wafer W together with the protective layer 11. Specifically, by stretching the diced ribbon 20, the semiconductor wafer W can be divided into small semiconductor chips X with the above-mentioned fragile portion inside the semiconductor wafer as the boundary. At this time, while the semiconductor wafer W is fragmented into semiconductor chips X, the protective layer 11 is also fragmented and fragmented.

The removal step of the third example, as shown in Figure 6D, can be implemented in the same manner as the removal step of the first example.

In the pick-up step of the third example, the semiconductor chip X is peeled off from the adhesive layer 22 of the wafer tape 20. When the pick-up step is performed in this way, the semiconductor chip X is peeled off from the adhesive layer 22 of the wafer tape 20.

In the third example, the bonding step can be performed in the same manner as in the first or second example.

In the third example, the steps not specifically mentioned can be performed in the same manner as the steps in the first or second example.

In the third example, the semiconductor wafer W may be ground using the back grinding tape B. When the grinding is performed, as shown in FIG6E , a protective layer 11 may be disposed between the back grinding tape B and the semiconductor wafer W. Even in such a state, since the grinding (back grinding) can be performed, the semiconductor wafer W can be thinned to a desired thickness as shown in FIG6F . Thereafter, as shown in FIG6G , the mounting step may be performed in a state where the back grinding tape B, the protective layer 11, and the semiconductor wafer W are stacked.

The protective sheet of the present invention and the manufacturing method of the electronic component device using the protective sheet are as exemplified above, but the present invention is not limited to the protective sheet or the manufacturing method as exemplified above. That is, various types used in general manufacturing methods of electronic component devices can be adopted within the scope that does not impair the effects of the present invention.

The matters disclosed in this specification include the following. (1) A protective sheet having a protective layer that is removed by a water-containing liquid after protecting at least a portion of the surface of a protected object; and the protective layer contains a solid hydrophilic polymer and a liquid compound containing a hydrophilic group in the molecule. (2) The protective sheet as described in (1) above, wherein the liquid compound is water-soluble. (3) The protective sheet as described in (1) or (2) above, wherein the protective layer contains 1 part by mass or more and 60 parts by mass or less of the liquid compound relative to 100 parts by mass of the hydrophilic polymer. (4) A protective sheet as described in any one of (1) to (3) above, wherein the storage elastic modulus E' of the protective layer at 70°C is less than 0.1 GPa. (5) A protective sheet as described in any one of (1) to (4) above, wherein when the dynamic viscoelasticity of the protective layer is measured, the peak temperature of the ratio of the loss elastic modulus E" to the storage elastic modulus E', Tanδ(E"/E'), is less than 70°C. (6) A protective sheet as described in any one of (1) to (5) above, wherein the hydrophilic polymer has a plurality of hydrophilic groups in the molecule; and the hydrophilic group is at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a sulfonic acid group, a pyrrolidone group, an amine-containing group, and a polyoxyethylene group. (7) A protective sheet as described in any one of (1) to (5) above, wherein the hydrophilic polymer is at least one selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble polyester polymer, polyethylene oxide, polyacrylic acid, and polyvinyl acetamide. (8) A protective sheet as described in any one of (1) to (7) above, wherein the liquid compound has a hydrophilic group in the molecule; the hydrophilic group is at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a sulfonic acid group, a pyrrolidone group, an amine-containing group, and a polyoxyethylene group. [Example]

Next, the present invention is further described in detail with experimental examples, but the present invention is not limited thereto.

(Examples 1 to 4, Comparative Examples 1 and 2, Reference Example 1) The protective sheet of each Example, each Comparative Example, and Reference Example 1 was produced in the following manner. Specifically, the following raw materials were prepared as the hydrophilic polymer and the liquid component. After dispersing the hydrophilic polymer and the liquid component in water, the mixture is heated to 90° C. to dissolve it, thereby preparing a PVA aqueous solution. Coat this PVA aqueous solution on release paper (PET film thickness 50μm). The release paper has a surface treated with polysilicone release, and the above-mentioned PVA aqueous solution is coated on this surface using an applicator. Furthermore, a drying process was performed at 110° C. for 2 minutes to form a protective layer with a thickness of 10 μm stacked on one side of the release paper (film formation). The details of each raw material of the protective layer used in each embodiment and each comparative example are as shown in Table 1 and below.

[Materials for protective layer] ・Hydrophilic polymer: polyvinyl alcohol (the following are all water-soluble) 1) PVA-1: Saponification degree: 82 (mol%), average degree of polymerization: 500 (Made by KURARAY Co., Ltd.) 2) PVA-2: Saponification degree: 65 (mol%), average degree of polymerization: 240 (Made by JAPAN VAM & POVAL) 3) PVA-3: Saponification degree: 98 (mol%), average degree of polymerization: 1200 (Made by Mitsubishi Chemical Corporation) ・Liquid ingredients (the following are all water-soluble) 1) PEG300: Polyethylene glycol 300 (average molecular weight 300, commercial product) Vapor pressure at 20℃: less than 2.0hPa 2) PEG600: Polyethylene glycol 600 (average molecular weight 600, commercial product) Vapor pressure at 20℃: less than 2.0hPa 3) Acrylic copolymer: Product name "ARUFON UC-3510" (manufactured by Toagosei Co., Ltd.) An acrylic copolymer having at least a structural unit of an alkyl (meth)acrylate and a structural unit of a carboxyl group-containing (meth)acrylate in the molecule Mass average molecular weight: around 2000, acid value: around 70 [mgKOH/g] Vapor pressure at 20℃: less than 2.0hPa 4) PEG400: Polyethylene glycol 400 (average molecular weight 400, commercial product) Vapor pressure at 20℃: less than 2.0hPa

[Table 1] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Comparison Example 1 Comparison Example 2 Reference Example 1 Hydrophilic polymer PVA-1 PVA-1 PVA-1 PVA-2 PVA-3 PVA-1 PVA-1 Liquid ingredients PEG300 PEG600 Acrylic acid copolymer PEG400 - - PEG600 Liquid component mixing ratio (to 100 parts by mass of hydrophilic polymer) 5 Quantity 40 servings 15 Servings 2 Quantity - - 70 servings Physical properties of protective layer E' [MPa] (70℃) 80 30 90 50 2500 200 Unable to determine MAX E” [℃] 20 10 30 30 >100 40 Unable to determine Peak temperature of tanδ[℃] 60 60 65 50 >100 70 Unable to determine Performance evaluation of protective layer Film making ○ (Good) ○ (Good) ○ (Good) ○ (Good) ○ (Good) ○ (Good) × (Defective) Processability ○ (Good) ○ (Good) ○ (Good) ○ (Good) ○ (Good) × (Defective) Unable to rate Adhesion (peel strength) [N/100mm] 2 2 10 60 0 20 Unable to rate Through the removal of water Slightly good good good good bad Slightly good good

The physical properties (dynamic viscoelasticity) of the prepared protective sheet were measured as follows. In addition, the performance of the protective sheet was evaluated.

<Dynamic viscoelasticity measurement of protective sheet> Using a solid viscoelasticity measuring device (RSA3 manufactured by TA Instruments), the dynamic viscoelasticity measurement of the protective sheet was carried out according to the above-mentioned measurement conditions. The storage elastic modulus E' at 70°C, the temperature at which the loss elastic modulus E" is the maximum, and the temperature at which tanδ (E"/E') reaches the peak were obtained.

<About the ease of making the protective layer (film formation)> The film formation was visually observed and evaluated in three levels: ○ (good), slightly good (△), and poor (×).

<About processability (how unlikely microcracks are to occur when the protective layer is cut)> Visually observe whether microcracks occur when the protective layer is cut into the desired size. The case where no microcracks occur is evaluated as ○ (good), and the case where microcracks occur is evaluated as poor (×).

＜Adhesion of the protective layer to the object to be protected＞ The peeling strength between the protective layer and the bare silicon wafer was measured using the above measurement method. When the peeling strength of the protective layer to the bare silicon wafer is above 0.2N/100mm, the adhesion can be said to be good.

<Protective layer removability by water> To remove the protective layer, the laminate of the bare silicon wafer and the protective layer was immersed in water at 25°C for 30 seconds. Afterwards, remove the water used to remove the protective layer. Further, a Fourier transform infrared spectrophotometer (FT-IR) was used to analyze the surface of the bare silicon wafer. Through this analysis, the presence or absence of residual organic matter is confirmed. In addition, the evaluation criteria are as follows. (Good) Almost no residual organic matter is observed (maximum absorption at 800 to 4000cm ^-1 is less than 0.1) (Slightly good) Residual organic matter is observed (maximum absorption at 800 to 4000cm ^-1 is 0.1 or more and 0.2 or less) (Poor) Residual organic matter was observed (maximum absorption at 800~4000cm ^-1 is greater than 0.2)

The results of the evaluation test conducted in the above manner are also shown in Table 1. From the above evaluation results, it can be seen that the protective layer of the protective sheet of the embodiment can protect the protected surface and can be easily removed by water. In addition, since the protective layer of the protective sheet of the embodiment contains the above-mentioned liquid component in addition to the above-mentioned solid hydrophilic polymer, it has good adhesion to the protected surface of the protected object and good processability (performance of suppressing the generation of micro cracks). [Cross-reference to related applications]

This case claims priority to Japanese Special Application No. 2022-111735, which is incorporated by reference into the description of this case. [Industrial Applicability]

The protective sheet of the present invention is suitably used, for example, in the manufacture of semiconductor devices including semiconductor integrated circuits.

1: Protective sheet 11: Protective layer 11’: Small piece of protective layer 15: Release paper 20: Wafer tape 21: Substrate layer 22: Adhesive layer 30: Wafer adhesive 50: Wafer adhesive film W: Semiconductor wafer X: Semiconductor wafer B: Back grinding tape

[Fig. 1] is a schematic cross-sectional view of an example of a protective sheet of the present embodiment cut in the thickness direction. [Fig. 2A] is a schematic cross-sectional view showing an example of a wetting step in a method for manufacturing an electronic component device. [Fig. 2B] is a schematic cross-sectional view showing an example of a protecting step in a method for manufacturing an electronic component device. [Fig. 2C] is a schematic cross-sectional view showing an example of a situation after the protecting step in a method for manufacturing an electronic component device. [Fig. 2D] is a schematic cross-sectional view showing an example of a removal step in a method for manufacturing an electronic component device (a schematic cross-sectional view showing an example of a situation in which a protective layer is removed from a protected surface of a protected object by a liquid containing water). [FIG. 3A] is a cross-sectional view of an example of cutting a wafer ribbon in the thickness direction. [FIG. 3B] is a cross-sectional view of an example of cutting a wafer adhesive film in the thickness direction. [FIG. 4A] is a schematic cross-sectional view showing the situation after the mounting step and the protection step are performed in the manufacturing method of the semiconductor device of the first example. [FIG. 4B] is a schematic cross-sectional view showing the situation during the blade wafer processing step in the manufacturing method of the semiconductor device of the first example. [FIG. 4C] is a schematic cross-sectional view showing the situation after the blade wafer processing step is performed in the manufacturing method of the semiconductor device of the first example. [FIG. 4D] is a schematic cross-sectional view showing the situation of the removal step in the manufacturing method of the semiconductor device of the first example. [FIG. 4E] is a schematic cross-sectional view showing the situation of the picking-up step in the manufacturing method of the semiconductor device of the first example. [FIG. 4F] is a schematic cross-sectional view showing the situation of the bonding step in the manufacturing method of the semiconductor device of the first example. [FIG. 5A] is a schematic cross-sectional view showing the situation of the semiconductor wafer after the half-cutting process in the manufacturing method of the semiconductor device of the second example. [FIG. 5B] is a schematic cross-sectional view showing the situation after the back grinding process in the manufacturing method of the semiconductor device of the second example. [FIG. 5C] is a schematic cross-sectional view showing the situation of the mounting step in the manufacturing method of the semiconductor device of the second example. [FIG. 5D] is a schematic cross-sectional view showing the situation of the expansion step in the manufacturing method of the semiconductor device of the second example. [FIG. 5E] is a schematic cross-sectional view showing a modified example of the semiconductor wafer after half-cutting in the second example of the method for manufacturing a semiconductor device. [FIG. 5F] is a schematic cross-sectional view showing a modified example of the semiconductor device after back grinding in the second example of the method for manufacturing a semiconductor device. [FIG. 5G] is a schematic cross-sectional view showing a modified example of the mounting step in the second example of the method for manufacturing a semiconductor device. [FIG. 6A] is a schematic cross-sectional view showing a condition in the invisible processing step in the third example of the method for manufacturing a semiconductor device. [FIG. 6B] is a schematic cross-sectional view showing a condition after the invisible processing step in the third example of the method for manufacturing a semiconductor device. [FIG. 6C] is a schematic cross-sectional view showing the expansion step in the third example of the method for manufacturing a semiconductor device. [FIG. 6D] is a schematic cross-sectional view showing the removal step in the third example of the method for manufacturing a semiconductor device. [FIG. 6E] is a schematic cross-sectional view showing a modified example of the situation before back grinding in the third example of the method for manufacturing a semiconductor device. [FIG. 6F] is a schematic cross-sectional view showing a modified example of the situation after back grinding in the third example of the method for manufacturing a semiconductor device. [FIG. 6G] is a schematic cross-sectional view showing a modified example of the mounting step in the third example of the method for manufacturing a semiconductor device.

1: Protective sheet

11: Protective layer

15: Release paper

Claims (5)

A protective sheet having a protective layer that is removed by a water-containing liquid after protecting at least a portion of the surface of a protected object; The protective layer contains a solid hydrophilic polymer and a liquid compound containing a hydrophilic group in the molecule. The protective sheet as claimed in claim 1, wherein the liquid compound is water-soluble. The protective sheet according to claim 1 or 2, wherein the protective layer contains not less than 1 part by mass and not more than 60 parts by mass of the liquid compound relative to 100 parts by mass of the hydrophilic polymer. The protective sheet as described in claim 1 or 2, wherein the storage elastic modulus E' of the protective layer at 70°C is less than 0.1 GPa. A protective sheet as described in claim 1 or 2, wherein, when the dynamic viscoelasticity of the protective layer is measured, the peak temperature of the ratio Tanδ(E”/E’) of the loss elastic modulus E” to the storage elastic modulus E’ is less than 70°C.