Protective sheet and method of manufacturing electronic component device

Abstract

To provide a protective sheet etc., that has excellent embedding properties for a protective layer and excellent peeling resistance of the protective layer stuck on a protection-object surface of a substrate, and also has the protective layer easily removed with liquid including water.SOLUTION: There is provided a protective sheet etc., comprising a protective layer stuck on a protection-object surface of a substrate, and the protective layer includes a water-soluble compound and has an adhesive strength of 0.5 N / 10 mm or more to a silicon wafer.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] The present invention relates to a protective sheet having a protective layer bonded to a surface to be protected of a substrate. The present invention also relates to a method for manufacturing an electronic component device including a step of removing the protective sheet after bonding the protective layer of the protective sheet to the surface to be protected of the substrate.

Background Art

[0002] Conventionally, a protective sheet used for manufacturing an electronic component device is known. This type of protective sheet includes, for example, a protective layer bonded to a surface to be protected of the electronic component device and a base material layer overlapping one surface of the protective layer.

[0003] This type of protective sheet is used, for example, during the steps of a method for manufacturing an electronic component device. In this type of method for manufacturing an electronic component device, for example, a step of mounting and temporarily fixing an element or the like as a workpiece on one surface of a substrate, a step of attaching the protective layer of the protective sheet to the other surface (surface to be protected) of the substrate, a step of processing the mounted element or the like, a step of removing the element or the like from the substrate, and a step of removing the protective layer from the substrate are provided. For example, in this way, the protective sheet is removed from the substrate and used after being once attached to the substrate.

[0004] As the protective sheet used in the method for manufacturing an electronic component device as described above, for example, a protective sheet including a protective layer formed of a resin composition containing an oxyalkylene group-containing polyvinyl alcohol-based resin having a saponification degree of 55 mol% or less and a base material layer is known (for example, Patent Document 1). The protective sheet described in Patent Document 1 can be used with the protective layer attached to one surface (surface to be protected) of the substrate. The base material layer of the protective sheet described in Patent Document 1 has a relatively high adhesion to the protective layer except when it is a release film.

[0005] According to the protective sheet described in Patent Document 1, the protective layer can protect the surface to be protected during temporary fixing, and moreover, the protective layer can be removed with water after temporary fixing.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the protective sheet described in Patent Document 1, when unevenness is formed on the surface to be protected of the substrate by bumps or the like, the protective layer may not necessarily be deformed sufficiently according to the unevenness, and a part of the protective layer may not be able to enter the concave portion. That is, the embedding property of the protective layer is not necessarily good. In addition, the protective sheet described in Patent Document 1 can be used by peeling the base material layer from the protective layer before removing the protective layer with water and leaving only the protective layer on the surface to be protected of the substrate. Even when only the protective layer is attached to the surface to be protected without the base material layer, there is also a usage method in which the protective layer is once covered with a covering tape and then the covering tape is peeled off. In such a case, when peeling the base material layer or the covering tape from the protective layer, since the adhesion between the surface to be protected of the substrate and the protective layer is relatively low, a part of the protective layer may adhere to the peeled base material layer or the covering tape. In order to prevent such problems, there is a demand for a protective sheet having good embedding property of the protective layer, good peel resistance of the protective layer adhered to the surface to be protected, and easy removal of the protective layer by a liquid containing water.

[0008] However, regarding a protective sheet having good embedding property of the protective layer, good peel resistance of the protective layer adhered to the surface to be protected of the substrate, and easy removal of the protective layer by a liquid containing water, it cannot be said that it has been sufficiently studied yet.

[0009] Therefore, an object of the present invention is to provide a protective sheet having good embedability of a protective layer, good peel resistance of the protective layer bonded to the surface to be protected of a substrate, and easy removal of the protective layer by a liquid containing water. Another object of the present invention is to provide a method for manufacturing an electronic component device using the above protective sheet.

Means for Solving the Problems

[0010] To solve the above problems, the protective sheet according to the present invention comprises a protective layer bonded to the surface to be protected of a substrate, wherein the protective layer contains a water-soluble compound, and the adhesion of the protective layer to a silicon wafer is 0.5 N / 10 mm or more.

[0011] The method for manufacturing an electronic component device according to the present invention is a method for manufacturing an electronic component device, including a temporary protection step of protecting the surface to be protected of a substrate with a protective sheet and then removing the protective sheet, wherein the protective sheet comprises a protective layer containing a water-soluble polymer compound and a base material layer overlapping one side of the protective layer, the adhesion of the protective layer to a silicon wafer is 0.5 N / 10 mm or more, the temporary protection step includes a first step of bonding the protective layer of the protective sheet to the surface to be protected and a second step of removing the protective sheet from the surface to be protected, and the second step includes a step of peeling the base material layer from the protective layer and a step of removing the protective layer by dissolving at least a part of the protective layer with a liquid containing water.

Effects of the Invention

[0012] The protective sheet according to the present invention has good embedability of the protective layer, good peel resistance of the protective layer bonded to the surface to be protected of the substrate, and easy removal of the protective layer by a liquid containing water. In the method for manufacturing an electronic component device according to the present invention, since the above-described protective sheet is used, the embedding property of the protective layer is good, the peel resistance of the protective layer adhered to the surface to be protected of the substrate is good, and the protective sheet can be easily removed by a liquid containing water.

Brief Description of the Drawings

[0013]

Figure 1A

Figure 1B

Figure 1C

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 3F

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 4E

Figure 4F

Figure 4G

Figure 4H

Figure 4I

Embodiments for Carrying Out the Invention

[0014] Hereinafter, each embodiment of the protective sheet and the method for manufacturing an electronic component device according to the present invention will be described in order with reference to the drawings. Note that the figures in the drawings are schematic diagrams and are not necessarily the same as the vertical and horizontal length ratios in the actual object.

[0015] The protective sheet 1 of the present embodiment includes at least a protective layer 12 containing a water-soluble polymer compound, as shown in FIGS. 1A to 1C respectively. The protective sheet 1 of the present embodiment may further include a base material layer 11 that overlaps one surface of the protective layer 12, as shown in FIGS. 1A and 1B respectively. The base material layer 11 may have, for example, as shown in FIG. 1A, an adhesive layer 11b that overlaps one side of the protective layer 12 and a support layer 11a that overlaps the adhesive layer 11b. On the other hand, the base material layer 11 may have only the support layer 11a, as shown in FIG. 1B for example. Note that the protective sheet 1 of the present embodiment may include two release liners 15 that overlap both surfaces of the protective layer 12, as shown in FIG. 1C for example.

[0016] The protective sheet 1 of the present embodiment is used, for example, by being bonded to one surface of a substrate to be protected (hereinafter also referred to as a surface to be protected). Specifically, the protective layer 12 can be used by being bonded to the surface to be protected. The above-mentioned protective layer 12 can be used as a pressure-sensitive sheet-like adhesive that can adhere to the surface to be protected by being pressed against the surface to be protected.

[0017] The protective sheet 1 is used, for example, to temporarily protect the surface to be protected of a substrate as an adherend. Examples of the substrate as an adherend include a glass substrate, a silicon wafer, a stainless steel (SUS) substrate, an organic material substrate, or a ceramic substrate.

[0018] Specifically, examples of the substrate as an adherend include a semiconductor wafer for obtaining a semiconductor chip, a semiconductor chip formed by fragmenting a semiconductor wafer, a connected circuit board formed by connecting a plurality of circuit boards, or a circuit board. The surface to be protected of these substrates usually has irregularities.

[0019] The semiconductor wafer W as the substrate S is configured, for example, as shown in FIG. 2. The semiconductor wafer W shown in FIG. 2 includes a semiconductor wafer main body W1 and a plurality of electrode portions W2 disposed on one surface of the semiconductor wafer main body W1. In the semiconductor wafer W, the one surface on which the plurality of electrode portions W2 are disposed serves as a circuit surface (circuit formation surface). Each electrode portion W2 has a plurality of bump electrodes, and adjacent bump electrodes are disposed at a relatively narrow interval. In other words, in each electrode portion W2, a plurality of bump electrodes are disposed at a high density. Since the plurality of bump electrodes are usually formed by performing a plating process on one surface of the semiconductor wafer main body W1, the plurality of electrode portions W2 are formed so as to protrude outward from one surface of the semiconductor wafer main body W1. In this type of semiconductor wafer W, the one surface on which the bump electrodes are disposed becomes the surface to be protected.

[0020] The semiconductor wafer W is diced (divided) along the dicing line D shown in FIG. 2, for example, and is fragmented into semiconductor chips. FIG. 2 shows a dicing line D for obtaining a semiconductor chip having one electrode portion W2. The semiconductor chip will have at least one electrode portion W2.

[0021] The electrode portion W2 of the semiconductor chip will be electrically connected to the electrode portions of other members. Examples of other members connected to the electrode portion W2 of the semiconductor chip include a circuit board or other semiconductor chips configured in the same manner as the above-described semiconductor chip. For example, the semiconductor chip may have a pair of electrode portions respectively disposed on both sides of the semiconductor chip body and a conduction portion that penetrates the semiconductor chip body in the thickness direction so that the pair of electrode portions are electrically conductive with each other. This type of semiconductor chip is called the TSV (Through Silicon Via) format. The electrode portion will be electrically connected to other members. In the TSV format semiconductor chip, only one surface may be the circuit surface, or both surfaces may be circuit surfaces respectively. In the TSV format semiconductor chip, since electrode portions can be formed on both sides respectively, both surfaces of the semiconductor chip can be protection target surfaces.

[0022] Examples of the semiconductor chip also include a sensor chip having a sensor element (for example, a light receiving element or a vibration element). Examples of the sensor chip include a CMOS (Complementary Metal-Oxide Semiconductor) chip.

[0023] For example, the semiconductor wafer W as shown in FIG. 2 may be used after one semiconductor chip is attached to each of the plurality of electrode portions W2 and then the semiconductor chips are resin-sealed respectively. That is, the semiconductor wafer W as shown in FIG. 2 may be used as a substrate for wafer level package (WLP). The wafer level package (WLP) is classified as the above-described electronic component connector.

[0024] Examples of the above-described electronic component connector include, for example, a pseudo-wafer. The pseudo-wafer has, for example, a support substrate and a package body formed by resin-sealing a plurality of semiconductor chips disposed on one surface of the support substrate. The pseudo-wafer may be only the package body removed from the support substrate. A rewiring layer may be formed on at least one surface of the pseudo-wafer. In this case, the protective layer 12 can be used to protect the rewiring layer. Note that a divided body obtained by dividing the above-described pseudo-wafer so as to include at least one semiconductor chip may be a substrate.

[0025] The protective layer 12 has an adhesiveness that can adhere to the surface to be protected of the substrate which is the adherend. By attaching the protective layer 12 of the protective sheet 1 to the surface to be protected, it is possible to prevent foreign matter from adhering to the surface to be protected until the protective layer 12 overlapping the surface to be protected is removed. Further, the protective layer 12 can be deformed according to the unevenness even if there are unevenness on the surface to be protected. Therefore, since it can sufficiently enter the recesses, it has good embedding properties. Furthermore, the protective sheet 1 is easily removed by a liquid containing water after being used, for example, for temporarily protecting the surface to be protected as described above. Note that the method of using the protective sheet 1 in which the protective layer 12 of the protective sheet 1 is attached to the substrate which is the adherend will be described in detail later.

[0026] [Base material layer of the protective sheet] As described above, the base material layer 11 may be composed of only the above-described support layer 11a, or may be a laminate of the support layer 11a and the above-described adhesive layer 11b.

[0027] The thickness of the base material layer 11 is not particularly limited, but is, for example, 1 μm or more and 300 μm or less. Such a thickness may be 3 μm or more, or may be 5 μm or more. Also, such a thickness may be 40 μm or less. Note that when the base material layer 11 is a laminate, the above thickness is the total thickness of the laminate.

[0028] (Support layer of the base material layer) The support layer 11a of the base material layer 11 is composed of, for example, a resin film. The support layer 11a may contain one type of resin or may contain a plurality of types of resins. The support layer 11a preferably contains 95% by mass or more of resin, and more preferably 98% by mass or more.

[0029] Examples of the resin contained in the support layer 11a include resins having a polar group. By the support layer 11a containing a resin having a polar group, the wettability on the surface of the support layer 11a is improved. In other words, the surface free energy of the support layer 11a can be increased. In terms of the adhesion between the support layer 11a and the adhesive layer 11b or the protective layer 12 being able to be better, the wettability on the surface of the support layer 11a is preferably relatively high.

[0030] Examples of the resin having the above polar group include, for example, polyester resins (such as PET), polyimide resins, or polyamideimide resins. Among such resins, at least one of polyimide resins and polyester resins is preferable. For example, the support layer 11a may be a polyimide resin film, may be a polyamideimide resin film, or may be a polyester resin film.

[0031] The thickness of the support layer 11a may be, for example, 5 μm or more and 50 μm or less.

[0032] (Adhesive layer of the base material layer) The adhesive layer 11b has, for example, pressure-sensitive adhesiveness. The adhesive layer 11b contains, for example, at least an acrylic resin. The acrylic resin will be described in detail later.

[0033] The adhesive layer 11b may have a configuration that is substantially non-reactive. This type of adhesive layer 11b may contain, for example, an acrylic resin and an isocyanate compound. In this case, the acrylic resin does not necessarily have a structural unit of a polymerizable group-containing (meth)acrylate (described in detail later) in the molecule.

[0034] On the other hand, the adhesive layer 11b may be configured such that a curing reaction proceeds upon irradiation with active energy rays (such as ultraviolet rays) and the adhesive force decreases. This type of adhesive layer 11b may contain, for example, an acrylic resin, an isocyanate compound, and a polymerization initiator (such as a photoinitiator).

[0035] The above acrylic resin has, for example, at least a structural unit of alkyl (meth)acrylate, a structural unit of hydroxyl group-containing (meth)acrylate, and a structural unit of polymerizable group-containing (meth)acrylate in the molecule. The structural unit is a unit that constitutes the main chain of the acrylic resin.

[0036] The above structural unit of alkyl (meth)acrylate is derived from an alkyl (meth)acrylate monomer. In other words, the molecular structure after the polymerization reaction of the alkyl (meth)acrylate monomer is the structural unit of alkyl (meth)acrylate. The notation "alkyl" represents the hydrocarbon moiety ester-bonded to (meth)acrylic acid. The number of carbon atoms in the alkyl moiety may be 6 or more and 12 or less.

[0037] Examples of the structural unit of the alkyl (meth) acrylate include structural units such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, or eicosyl (meth) acrylate.

[0038] The above acrylic resin has a structural unit of a hydroxyl group-containing (meth) acrylate, and the hydroxyl group of such a structural unit easily reacts with an isocyanate group. By coexisting the acrylic resin having a structural unit of a hydroxyl group-containing (meth) acrylate and an isocyanate compound in the adhesive layer 11b, the adhesive layer 11b can be appropriately cured. Therefore, the adhesive layer 11b can be sufficiently gelled. Thus, the adhesive layer 11b can exhibit adhesive performance while maintaining its shape.

[0039] The structural unit of the hydroxyl group-containing (meth)acrylate is preferably a structural unit of a hydroxyl group-containing C2-C4 alkyl (meth)acrylate. The notation "C2-C4 alkyl" represents the hydrocarbon moiety ester-bonded to (meth)acrylic acid and the number of carbon atoms thereof. In other words, the hydroxyl group-containing C2-C4 alkyl (meth)acrylate monomer refers to a monomer in which (meth)acrylic acid and an alcohol having 2 or more and 4 or less carbon atoms (usually a dihydric alcohol) are ester-bonded. The hydrocarbon moiety of C2-C4 alkyl is usually a saturated hydrocarbon.

[0040] Examples of the structural unit of the hydroxyl group-containing C2-C4 alkyl (meth)acrylate include structural units of each of hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, or hydroxybutyl (meth)acrylate such as hydroxy n-butyl (meth)acrylate or hydroxy iso-butyl (meth)acrylate.

[0041] The above acrylic resin contains a structural unit of a polymerizable group-containing (meth)acrylate having a polymerizable unsaturated double bond in the side chain. Since the above acrylic resin contains a structural unit of a polymerizable group-containing (meth)acrylate, radicals can be generated from a photoinitiator by irradiation with active energy rays such as ultraviolet rays, and by the action of these radicals, the acrylic resins can be crosslinked with each other. As a result, the adhesive force of the adhesive layer 11b can be reduced by irradiation. Note that ultraviolet rays, radiation, and electron beams are employed as the active energy rays.

[0042] Specifically, the structural unit of the polymerizable group-containing (meth)acrylate may have a molecular structure in which the isocyanate group of the isocyanate group-containing (meth)acrylate monomer is urethane-bonded to the hydroxyl group in the structural unit of the above-described hydroxyl group-containing (meth)acrylate.

[0043] The structural unit of the polymerizable group-containing (meth)acrylate having a coincident group can be prepared after the polymerization reaction for synthesizing the acrylic resin. For example, after copolymerization of an alkyl (meth)acrylate monomer and a hydroxyl group-containing (meth)acrylate monomer, the hydroxyl group in a part of the structural unit of the hydroxyl group-containing (meth)acrylate and the isocyanate group of the isocyanate group-containing polymerizable monomer are subjected to a urethanization reaction, whereby the structural unit of the above polymerizable group-containing (meth)acrylate can be obtained.

[0044] The above isocyanate group-containing (meth)acrylate monomer preferably has one isocyanate group and one (meth)acryloyl group in the molecule. Examples of such a monomer include 2-isocyanatoethyl (meth)acrylate.

[0045] The adhesive layer 11b may further contain an isocyanate compound. A part of the isocyanate compound may be in a state after reaction by a urethanization reaction or the like. The isocyanate compound has a plurality of isocyanate groups in the molecule. By the isocyanate compound having a plurality of isocyanate groups in the molecule, the crosslinking reaction between the acrylic resins in the adhesive layer 11b can be advanced.

[0046] Examples of the isocyanate compound include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, or araliphatic diisocyanates. Further, examples of the isocyanate compound include polymer polyisocyanates such as dimers and trimers of diisocyanates, or polymethylene polyphenylene polyisocyanates. One of the above isocyanate compounds can be used alone or in combination of two or more.

[0047] The polymerization initiator that can be contained in the adhesive layer 11b is a compound that can initiate a polymerization reaction by the added thermal or light energy. When the adhesive layer 11b contains a polymerization initiator, when thermal energy or light energy is applied to the adhesive layer 11b, the crosslinking reaction between acrylic resins can proceed, and the adhesive layer 11b can be cured. Thereby, the adhesive force of the adhesive layer 11b can be reduced, and it can be easily peeled off between the protective layer 12 and the cured adhesive layer 11b. As the polymerization initiator, for example, a commercially available general photoinitiator or thermal polymerization initiator is adopted.

[0048] The adhesive layer 11b may further contain additives. Examples of the additives include antioxidants, ultraviolet absorbers, or surfactants.

[0049] The thickness of the adhesive layer 11b may be, for example, 5 μm or more and 150 μm or less.

[0050] [Protective layer of the protective sheet] The protective layer 12 contains a water-soluble polymer compound. The water-soluble polymer compound has a hydrophilic group in the molecule. The protective layer 12 preferably contains 90% by mass or more of the water-soluble polymer compound, more preferably 95% by mass or more, and still more preferably 99% by mass or more. Thereby, the protective layer 12 can be more easily removed by a liquid containing water.

[0051] The protective layer 12 contains, as water-soluble compounds, for example, a first water-soluble compound and a second water-soluble compound. The first water-soluble compound is preferably a compound having a polyoxyethylene structure in the molecule. The second water-soluble compound is preferably a water-soluble polyester resin having a mass average molecular weight of 2,000 or more.

[0052] Both the first water-soluble polymer compound and the second water-soluble polymer compound have water solubility such that all the thin films (thickness 50 μm or less) of each water-soluble polymer compound dissolve when immersed in water at 40°C.

[0053] The protective layer 12 has a hydrophilicity of a predetermined level or more. When the protective layer 12 has a hydrophilicity of a predetermined level or more, usually, at least a part of the above-mentioned protective layer 12 dissolves in a liquid containing water. Since the protective layer 12 has a hydrophilicity of a predetermined level or more, it is configured such that at least a part of it dissolves when it comes into contact with a liquid containing water and is removed from the surface of the substrate.

[0054] The adhesive strength of the protective layer 12 to the silicon wafer is 0.5 [N / 10 mm] or more. Such an adhesive strength is preferably 2.0 [N / 10 mm] or more, more preferably 3.0 [N / 10 mm] or more, and particularly preferably 5.0 [N / 10 mm] or more. When the adhesive strength of the protective layer 12 to the silicon wafer is greater, when the substrate layer 11 or the like that overlaps the protective layer 12 is peeled off from the protective layer 12, the protective layer 12 bonded to the surface to be protected of the substrate is less likely to be peeled off together with the substrate layer 11. In addition, it is possible to further suppress the unintentional exposure of the surface of the protected silicon wafer. The adhesive strength of the protective layer 12 to the silicon wafer may be 10.0 [N / 10 mm] or less.

[0055] For example, by increasing the molecular weight of the water-soluble polymer compound contained in the protective layer 12, the above-mentioned adhesive strength can be increased. On the other hand, for example, by decreasing the molecular weight of the water-soluble polymer compound contained in the protective layer 12, the above-mentioned adhesive strength can be decreased.

[0056] The adhesive strength of the protective layer 12 to the silicon wafer (silicon bare wafer) is measured under the following measurement conditions. Taking the protective sheet 1 having the configuration shown in FIG. 1C as a specific example for explanation, even for the protective sheet 1 having the configuration shown in FIG. 1A or FIG. 1B, the above-mentioned adhesive strength is measured in the same manner. First, one of the two release liners 15 is peeled off from the protective layer 12 to expose one surface of the protective layer 12. A backing tape is bonded to the exposed surface to obtain a first test piece. The bonding of the backing tape is performed at a temperature of 25 °C using a hand roller. Next, after cutting the first test piece to a width of 100 mm, the other release liner is peeled off from the protective layer 12 to expose the other surface of the protective layer 12. Such an exposed surface is bonded to the bare wafer to obtain a second test piece (measurement sample). The bonding to the bare wafer is performed using a 2 kg standard roller (manual adhesion test press wheel adhesive tape adhesion tester) under the conditions of a temperature of 90 °C and a speed of 10 mm / second. After bonding, natural cooling (cooling) is performed for 20 minutes or more. Subsequently, under the conditions of a temperature of 23 °C, a peeling angle of 180 °, and a peeling speed of 300 mm / min, the protective layer 12 and the backing tape are peeled off from the bare wafer, and the peeling force of the measurement sample is measured. Then, the measured peeling force is taken as the above-mentioned adhesive strength. As the measuring device, for example, an autograph (manufactured by SHIMADZU Corporation) can be used.

[0057] The storage elastic modulus of the protective layer 12 at 70 °C is preferably 100,000 Pa or less, and more preferably 50,000 Pa or less. When the storage elastic modulus of the protective layer 12 at 70 °C is 100,000 Pa or less, sufficient embedding property can be exhibited even when the temperature for bonding the protective layer 12 to the surface to be protected is relatively low. Note that the storage elastic modulus of the protective layer 12 at 70 °C may be 10,000 Pa or more.

[0058] For example, by increasing the molecular weight of the water-soluble polymer compound contained in the protective layer 12, the above-mentioned storage elastic modulus can be increased. On the other hand, for example, by decreasing the molecular weight of the water-soluble polymer compound contained in the protective layer 12, the above-mentioned storage elastic modulus can be decreased.

[0059] The storage elastic modulus (shear storage elastic modulus) of the protective layer 12 is measured as follows. Specifically, in the measurement of the storage viscoelasticity of the protective layer 12, the protective layer is laminated as necessary to prepare a sheet-like measurement sample having a thickness of 250 μm or more and 350 μm or less. The measurement sample is punched out with a punch having a diameter of 8 mm to prepare a test piece. Then, the measurement is performed under the following measurement conditions, and the measured value (G’) [Pa] of the storage elastic modulus at 70 °C is read. Measuring device: Rheometer (For example, "MARS III" manufactured by HAAKE) Measured temperature: Heating from 40°C to 100°C (heating rate 10°C / min) Measured frequency: 1 Hz (1 / second) Strain: 5% Measured gap: 0.250 mm Measurement mode: Shear mode Measurement terminals: Parallel plates with a measurement surface diameter of 8 mm

[0060] In the above protective sheet 1, the thickness of the protective layer 12 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, or may be 5 μm or more. Also, such a thickness may be 40 μm or less. When the protective layer 12 is a laminate, the above thickness is the total thickness of the laminate.

[0061] The first water-soluble compound is, for example, a compound having a polyoxyethylene structure in the molecule. The polyoxyethylene structure acts as a hydrophilic group. Since the first water-soluble compound has a polyoxyethylene structure as a hydrophilic group in the molecule, it can be more easily dissolved in a liquid containing water even at room temperature.

[0062] Examples of the first water-soluble compound include polyethylene glycol (PEG) having only a polyoxyethylene structure in the molecule (for example, with a molecular weight of less than 20,000), polyethylene oxide (PEO) having only a polyoxyethylene structure in the molecule (for example, with a molecular weight of 20,000 or more), and polyalkylene oxide copolymers having a polyoxyethylene structure and a polyoxypropylene structure in the molecule (for example, with a molecular weight of 50,000 or more), etc. The polyalkylene oxide copolymer may be a block copolymer having a block of a polyoxyethylene structure and a block of a polyoxypropylene structure in the molecule, or may be a random copolymer of ethylene oxide and propylene oxide.

[0063] The mass average molecular weight Mw and the average degree of polymerization of the above-exemplified first water-soluble compound can be measured by aqueous gel permeation chromatography (aqueous GPC). The details of the measurement conditions are as follows. <Measurement conditions> · Analytical device: Agilent, 1260 Infinity · Columns: TSKgel G6000PWXL and TSKgel G3000PWXL (manufactured by Tosoh Corporation) The above two columns are connected in series. · Column temperature: 40 °C · Eluent: 0.2 M aqueous sodium nitrate solution · Injection volume: 100 μL · Detector: Differential refractometer (RI) · Standard sample: PEG standard sample The mass average molecular weight Mw of the sample to be measured (PEG, PEO, etc.) is calculated by GPC measurement using the PEG standard sample.

[0064] When the above water-soluble polymer compound has a polyoxypropylene structure in addition to the polyoxyethylene structure in the molecule, the adhesion of the protective layer 12 to the surface to be protected can be further enhanced. Also, the heat resistance of the protective layer 12 can be further enhanced.

[0065] The mass average molecular weight Mw of the above polyethylene oxide (PEO) is preferably 200,000 (200,000) or less. When the mass average molecular weight Mw is 200,000 or less, the first water-soluble compound can have a sufficiently low softening point. Thereby, the adhesion of the protective layer 12 to the surface to be protected can be improved more favorably. Also, the protective layer 12 can be efficiently removed from the surface to be protected by a liquid containing water in a shorter time. Note that the mass average molecular weight Mw may be, for example, 50,000 or more.

[0066] As the above polyethylene glycol (PEG), polyethylene oxide (PEO), or polyalkylene oxide copolymer, which is the first water-soluble compound, commercially available products can be used.

[0067] The second water-soluble compound is, for example, a water-soluble polyester resin. The water-soluble polyester resin is a dehydration condensate of at least a polycarboxylic acid (e.g., terephthalic acid) and a polyol. The water-soluble polyester resin may have a sulfo group (-SO3H) or a carboxy group (-COOH) in the molecule. These groups may be in a salt state.

[0068] The water-soluble polyester resin is water-soluble because it has the following physical properties. Specifically, the water-soluble polyester has at least one of the following physical properties (A) to (D). (A) When water at room temperature (23 ± 2°C) is sprayed onto the entire surface of a 20-μm-thick thin film formed of the water-soluble polyester at a spray pressure of 0.005 MPa for 20 minutes, the entire thin film dissolves in water. (B) When water at 50°C is sprayed onto the entire surface of a 20-μm-thick thin film formed of the water-soluble polyester at a spray pressure of 0.005 MPa for 10 minutes, the entire thin film dissolves in water. (C) When the powder of the water-soluble polyester and water at room temperature are mixed at a mass ratio of powder: water = 1:5 to obtain a mixed solution, and the mixed solution is irradiated with ultrasonic waves for 20 minutes, the powder of the water-soluble polyester completely dissolves in water. (D) When the powder of the water-soluble polyester and water at 50°C are mixed at a mass ratio of powder: water = 1:5 to obtain a mixed solution, and the mixed solution is irradiated with ultrasonic waves for 10 minutes, the powder of the water-soluble polyester completely dissolves in water.

[0069] The mass average molecular weight Mw of the water-soluble polyester resin may be 5,000 or more, may be 7,000 or more, or may be 10,000 or more. In addition, the mass average molecular weight Mw of the water-soluble polyester resin is preferably 40,000 (forty thousand) or less, more preferably 30,000 (thirty thousand) or less, still more preferably 20,000 (twenty thousand) or less, and particularly preferably 15,000 or less. When the mass average molecular weight Mw of the water-soluble polyester resin is 40,000 or less, it becomes easier to form the protective layer 12 into a film shape, and the embedding property of the protective layer 12 can be improved more favorably. In addition, the protective layer 12 can more sufficiently suppress the adhesion of fine foreign matters to the surface to be protected. Further, the protective layer 12 is more easily removed by a liquid containing water.

[0070] The water-soluble polyester resin may be a resin exhibiting an acid value. The acid value of the water-soluble polyester resin may be 10 mgKOH / g or less. The acid value of the water-soluble polyester resin is a value measured according to the neutralization titration method defined in JIS K0070:1992.

[0071] As the water-soluble polyester resin which is the second water-soluble compound, a commercially available product can be used.

[0072] In addition to the above-described compounding components, the protective layer 12 of the present embodiment may further contain, for example, a surfactant, a plasticizer, and the like.

[0073] The protective layer 12 has an adhesiveness that can adhere to the surface to be protected of the substrate. Further, when the base material layer 11 has only the support layer 11a, the protective layer 12 has an adhesiveness that can adhere to the support layer 11a. When the base material layer 11 has the support layer 11a and the adhesive layer 11b, since the protective layer 12 is in contact with the adhesive layer 11b, the protective layer 12 has an adhesiveness that can adhere to the adhesive layer 11b.

[0074] In addition, as shown in, for example, FIG. 1B, the protective sheet 1 of the present embodiment may include a release liner 15 that covers one surface of the protective layer 12 (one side of the protective layer 12 that does not overlap with the base material layer 11) in a state before being used. The release liner 15 is used to protect the protective layer 12 and is peeled off immediately before, for example, bonding the protective layer 12 to a substrate.

[0075] The protective sheet 1 of this embodiment can be manufactured by a general method, for example, as follows. First, a water-soluble polymer compound is dissolved in a solvent containing water. When dissolving, heating may be performed. As the solvent, an organic solvent other than water may be used. As the organic solvent, an aqueous organic solvent that dissolves in water at an arbitrary ratio is preferable. Examples of such aqueous organic solvents include methanol, ethanol, isopropyl alcohol, and the like. Next, the polymer solution prepared as described above is applied (coated) to the base material layer 11 or the release liner 15. After coating, by heating at a temperature at which the solvent volatilizes, the protective layer 12 overlapping the base material layer 11 or the release liner 15 is formed. Although the protective sheet 1 can be manufactured in this way, the manufacturing method of the protective sheet is not limited to the method exemplified as above.

[0076] The protective sheet 1 is used, for example, as an auxiliary tool for manufacturing an electronic component device. The protective sheet 1 is temporarily used, for example, during the process of manufacturing an electronic component device. Therefore, the manufactured electronic component device does not include the protective sheet 1.

[0077] The electronic component device may be, for example, a semiconductor device such as a semiconductor integrated circuit including a semiconductor chip, a device including a system LSI having complementary MOS (CMOS), or a device including a mechanical element component, a sensor, an actuator, or an electronic circuit integrated by a microfabrication technique on a single silicon substrate, glass substrate, or organic material substrate, etc. (MEMS Micro Electro Mechanical Systems). Note that the manufactured electronic component device may be a device including a circuit board.

[0078] Examples of the substrate to which the protective layer 12 of the protective sheet 1 of this embodiment is bonded include various substrates. Examples of the substrate include, as described above, a semiconductor wafer, a circuit board, or a connected circuit board (such as a pseudo-wafer) formed by connecting a plurality of circuit boards.

[0079] Next, a method for manufacturing the electronic component device of the present embodiment will be described.

[0080] The method for manufacturing the electronic component device of the present embodiment is a method for manufacturing an electronic component device, including a temporary protection step of protecting the surface to be protected of the substrate with a protective sheet and then removing the protective sheet, wherein the protective sheet includes a protective layer containing a water-soluble polymer compound and a base material layer overlapping one side of the protective layer, the adhesion of the protective layer to the silicon wafer is 0.5 N / 10 mm or more, the temporary protection step includes a first step of bonding the protective layer of the protective sheet to the surface to be protected (hereinafter also referred to as the bonding step), and a second step of removing the protective sheet from the surface to be protected (hereinafter also referred to as the removing step), the second step (removing step) includes a step of peeling the base material layer from the protective layer (hereinafter also referred to as the peeling step), and a step of dissolving at least a part of the protective layer with a liquid containing water to remove the protective layer (hereinafter also referred to as the dissolving step).

[0081] In the above temporary protection step, by the bonding step, for example, as shown in FIG. 3A, using the protective sheet 1 having the base material layer 11 on one side of the protective layer 12, the protective layer 12 of the protective sheet 1 is bonded to the surface to be protected of the substrate S to protect the surface to be protected of the substrate S. Then, by the peeling step, for example, as shown in FIG. 3B, the base material layer 11 is peeled from the protective layer 12.

[0082] The method for manufacturing the electronic component device of the present embodiment may further include a step of fragmenting at least the protective layer 12 into small pieces to produce small pieces 12' of a plurality of protective layers (hereinafter also referred to as the fragmenting step), as shown in FIGS. 3C and 3D respectively. In the dicing process, for example, as shown in FIG. 3C, only the protective layer 12 among the laminate of the overlapping substrates S and the protective layer 12 may be diced to produce a plurality of chips 12'. On the other hand, for example, as shown in FIG. 3D, by dicing the laminate of the overlapping substrates S and the protective layer 12, a plurality of laminated chips in which the diced chips S' of the substrate overlap with the chips 12' of the protective layer may be produced.

[0083] In the above temporary protection process, in the dissolution process, for example, as shown in FIG. 3E or FIG. 3F, each chip 12' of the protective layer overlapping the surface to be protected of the substrate S (such as the circuit surface of the chip S') is removed by a liquid containing water.

[0084] In the method for manufacturing an electronic component device according to the present embodiment, at least one surface of the substrate is protected by the protective layer 12. The surface to be protected (the surface to be protected) may be only one side of the substrate or both sides. Note that circuit components (described in detail later) may or may not be arranged on the surface to be protected.

[0085] The material of the substrate is not particularly limited as long as it is plate-shaped. Examples of the material of the substrate include glass, silicon, stainless steel (SUS), plastic, or ceramic. Examples of the substrate include a semiconductor wafer, a sensor wafer such as CMOS or MEMS, a dummy wafer, or a circuit board.

[0086] In the above-mentioned pasting step, the protective layer 12 may be overlaid on the surface of the substrate on the side where at least one of the circuit wiring, the sensor unit, and the electrode unit is arranged as a circuit component. For example, the protective layer 12 may be overlaid on one side (circuit surface) of the substrate on which the circuit wiring is arranged, on one side of the substrate on which the sensor unit is arranged, or on one side of the substrate on which the electrode unit is arranged. In the above-mentioned pasting step, it is preferable to overlay the protective layer 12 on at least one surface of the substrate so as to cover the circuit wiring, the sensor unit, or the electrode unit with the protective layer 12. Examples of the circuit components include circuit wiring, electrode units, or elements such as transistors, diodes, or sensor units (light receiving sensors or vibration sensors, etc.).

[0087] Hereinafter, taking the case of manufacturing a semiconductor device (semiconductor integrated circuit) as an electronic component device as an example, a detailed description will be given.

[0088] Generally, a method for manufacturing a semiconductor device includes a pre-step of forming a circuit surface on one side of a bare wafer by a highly integrated electronic circuit, and a post-step of cutting out chips from the semiconductor wafer on which the circuit surface is formed and performing assembly.

[0089] In the pre-step, a circuit surface is formed on one side of the bare wafer to produce a semiconductor wafer W as a substrate. Circuit components such as bumps, electrode units, pillar terminals, or semiconductor chips may be arranged on the circuit surface. As a result, the surface on the side where the circuit surface is formed has irregularities. In the present embodiment, a semiconductor wafer W having a circuit surface, which is a surface to be protected, formed on one side and having irregularities on the circuit surface is used as a substrate. Such a semiconductor wafer W is further processed in the post-step.

[0090] In the post-step, for example, at least a pasting step of pasting the protective layer 12 of the protective sheet 1 on the surface to be protected (circuit surface) of the semiconductor wafer W as a substrate, and a removing step of removing the protective layer 12 pasted on the surface to be protected (circuit surface) are performed as a temporary protection step. If necessary, between the above-mentioned pasting step and removing step, a grinding step may be performed on the semiconductor wafer with the protective sheet 1 pasted thereon to reduce the thickness of the semiconductor wafer. In the removing step, a peeling step of peeling the base material layer 11 from the protective layer 12 bonded to the circuit surface of the semiconductor wafer W and a dissolving step of dissolving at least a part of the protective layer 12 with a liquid containing water to remove the protective layer 12 bonded to the circuit surface of the semiconductor wafer W are performed. If necessary, between the above-mentioned peeling step and dissolving step, laser grooving processing (described in detail later) or plasma dicing processing (described in detail later) of the semiconductor wafer W may be performed. When performing the dissolving step, the protective layer 12 may be fragmented by a fragmenting step. In other words, in the dissolving step, the fragments 12' of the fragmented protective layer may be removed with a liquid containing water.

[0091] The post-processes as described above include, for example, the above-mentioned pasting step, the above-mentioned grinding step performed if necessary, a mounting step of fixing the semiconductor wafer by bonding the surface of the semiconductor wafer opposite to the circuit surface to the adhesive fixing layer 22 of the dicing tape 20, the peeling step of the above-mentioned removing step, the fragmenting step of fragmenting at least the protective layer 12 performed if necessary, the dissolving step of the above-mentioned removing step, and a taking-out step of peeling and taking out the semiconductor wafer W or semiconductor chip from the adhesive fixing layer 22 of the dicing tape 20. The semiconductor integrated circuit (semiconductor device) is manufactured through these steps, for example.

[0092] In the manufacturing method of the semiconductor device (electronic component device) of the present embodiment, at least the protective layer 12 of the protective sheet 1 and the dicing tape 20 (see FIG. 4C) are used to manufacture the semiconductor device as follows. The dicing tape 20 has a base layer 21 and the above-mentioned adhesive fixing layer 22 and is used as an auxiliary tool for manufacturing the semiconductor device. As the dicing tape 20, a commercially available product can be used.

[0093] In the attaching step, for example, as shown in FIG. 4A, the protective layer 12 of the protective sheet 1 is superposed on the back surface of the semiconductor wafer W. In the attaching step, for example, the protective layer 12 is superposed on the back surface by directly pressing and attaching the protective layer 12 to the back surface. By superposing the protective layer 12 on the back surface of the semiconductor wafer W, the back surface can be protected by the protective layer 12 until the protective layer 12 is removed. Therefore, it is possible to prevent dust or the like from adhering to the back surface of the semiconductor wafer W covered with the protective layer 12.

[0094] If necessary, the above grinding step is performed. For example, in a state where the semiconductor wafer W, the protective layer 12, and the base material layer 11 are laminated, grinding is performed on the surface of the semiconductor wafer W where no circuit components are arranged. Specifically, as shown in FIG. 4B, grinding by a grinding pad K (back grinding) is performed until the semiconductor wafer W reaches a predetermined thickness. The thickness of the semiconductor wafer W is reduced to a predetermined thickness by the grinding step.

[0095] In the mounting step, as shown in FIG. 4C, while attaching the dicing ring R to the adhesive fixing layer 22 of the dicing tape 20, the semiconductor wafer W is attached and fixed to the adhesive fixing layer 22 of the dicing tape 20. When the above grinding step is not performed, after attaching and fixing the semiconductor wafer W to the adhesive fixing layer 22 of the dicing tape 20, the attaching step of the temporary protection step may be performed by superposing the protective layer 12 on the surface to be protected (back surface) of the semiconductor wafer W.

[0096] In the peeling step of the removing step, for example, as shown in FIG. 4D, before removing the protective layer 12 from the surface of the semiconductor wafer W, the base material layer 11 is peeled off from the surface of the protective layer 12. In the peeling step, before peeling off the base material layer 11, the protective layer 12 may be irradiated with active energy rays such as ultraviolet rays. In this case, the protective layer 12 containing a photopolymerization initiator or the like is adopted as described above.

[0097] After the above peeling step, if necessary, a dicing step of dicing at least the protective layer 12 into small pieces is performed. For example, the protective layer 12 and the semiconductor wafer may be diced into semiconductor chips (dies) by laser grooving processing and plasma dicing processing of the semiconductor wafer W.

[0098] In the dicing step, for example, as shown in FIG. 4E or FIG. 4F, only the protective layer 12 or the protective layer 12 and the semiconductor wafer W are diced. In the laser grooving process, for example, as shown in FIG. 4E, while protecting the circuit surface with the protective layer 12, the circuit surface is irradiated with laser light L. For example, when an insulating film called a Low-k film having a relative dielectric constant smaller than that of SiO2 is on the circuit surface, the laser grooving process can be performed. The wiring layer including the Low-k film is removed by laser light, and two thin grooves (grooves) are formed at intervals in the dicing street. Thereafter, the semiconductor wafer W can be diced by the subsequent plasma dicing process. In the laser grooving process, foreign matters such as fragments of the insulating film may be generated with the irradiation of the laser light L. At this time, since the surface to be protected of the semiconductor wafer W is protected by the protective layer 12, it is possible to suppress the adhesion of foreign matters to the surface to be protected.

[0099] In the plasma dicing process, for example, as shown in FIG. 4F, the semiconductor wafer W is cut into a predetermined size to form semiconductor chips. By forming the two grooves as described above, plasma can be irradiated only between the two grooves. The plasma dicing process is performed according to a conventional method, for example, using a plasma generator.

[0100] In the dicing process, for example, as shown in FIG. 4G, with the semiconductor wafer W with the protective layer 12 attached fixed on the adhesive fixing layer 22 of the dicing tape 20, an expand operation may be performed to stretch the dicing tape 20 in the plane direction so as to increase the surface area of the dicing tape 20. Thereby, the laminate of the semiconductor wafer W and the protective layer 12 is divided and diced, and further, the intervals between the adjacent semiconductor chips X formed by dicing may be widened along the plane direction. The semiconductor wafer W needs to be diced by the above expand operation. Therefore, the semiconductor wafer W diced as described above is designed to be cut well. For example, inside the semiconductor wafer W, a vulnerable site for dicing into semiconductor chips X (dies) is formed. The vulnerable site can be formed by irradiating the semiconductor wafer W with laser light or the like using a commercially available stealth dicing device. Since the protective layer 12 also needs to be diced by the above expand operation, it is designed to be cut well.

[0101] The details of the above expand operation are as follows. For example, as shown in FIG. 4G, after attaching the dicing ring R to the adhesive fixing layer 22 of the dicing tape 20, the dicing ring R is fixed to the holder H of the expand device. By pushing up the pushing member U provided in the expand device from below the dicing tape 20, the dicing tape 20 is stretched to expand in the plane direction. Thereby, the semiconductor wafer W and the protective layer 12 are diced under specific temperature conditions. The above temperature conditions are, for example, -20°C or higher and 0°C or lower. By lowering the pushing member U, the expanded state is released (the low-temperature expand operation up to here). Furthermore, under higher temperature conditions (for example, 10°C or higher and 25°C or lower), the dicing tape 20 is stretched so as to increase the surface area of the dicing tape 20. Thereby, the adjacent semiconductor chips X are separated from each other in the plane direction of the dicing tape 20, and the kerf (interval) is further widened (room-temperature expand operation). By stretching the dicing tape 20 in the plane direction so as to increase the area of the dicing tape 20, the semiconductor wafer W can be divided into small semiconductor chips X with the above-mentioned fragile part inside the semiconductor wafer as a boundary. At this time, while the semiconductor wafer W is fragmented into semiconductor chips X, the protective layer 12 is also divided and fragmented.

[0102] In the dissolution step of the removal step, as shown in, for example, FIG. 4H or FIG. 4I, a liquid containing water is brought into contact with a plurality of small pieces 12' of the protective layer, and at least a part of each small piece 12' is dissolved with the above liquid, thereby removing each small piece 12' of the protective layer from the surface (surface to be protected) of the semiconductor wafer W or the semiconductor chip X. By removing the small pieces 12' of the protective layer in this way, all of the plurality of small pieces 12' of the protective layer can be removed relatively easily, and the number of foreign substances attached to the surface to be protected can be reduced relatively easily by the above liquid. Also, the surface (surface to be protected) of the semiconductor wafer W where the protective layer 12 overlapped, or the surface (surface to be protected) of each semiconductor chip X where the small pieces 12' of the protective layer overlapped can be washed with the liquid.

[0103] In the dissolution step of the removal step, at least a part of the fragmented protective layer (a plurality of small pieces 12' of the protective layer) is dissolved by the above liquid. Therefore, the adhesion force of the small pieces 12' of the protective layer to the semiconductor chip X becomes weak, and it becomes easy to peel off from the semiconductor chip X. Thereby, a plurality of small pieces 12' of the protective layer can be removed relatively easily.

[0104] 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 of water, 70% by mass or more of water, 80% by mass or more of water, or 90% by mass or more of water. In addition to water, the above liquid may contain components soluble in water. Such components include, for example, water-soluble organic solvents. Examples of such water-soluble organic solvents include monohydric alcohols having 4 or fewer carbon atoms such as methanol, ethanol, propanols such as isopropyl alcohol, or butanols such as t-butanol.

[0105] In the dissolution step of the removal process, a small piece 12' of the protective layer may be immersed in the agitated above liquid to bring the liquid into contact with the small piece 12' of the protective layer. Alternatively, the liquid sprayed from a nozzle or the like may be brought into contact with the small piece 12' of the protective layer. The temperature of the above liquid is not particularly limited and may be set, for example, at 10°C or higher and 90°C or lower.

[0106] For example, in the dissolution step of the removal process, while rotating a disk-shaped stage that supports the dicing tape 20 from below in the circumferential direction, the above liquid is sprayed toward the semiconductor wafer W attached to the dicing tape 20 or the semiconductor chip X attached to the dicing tape 20. Thereby, a plurality of small pieces 12' of the protective layer overlapping the semiconductor wafer W or the semiconductor chip X can be removed respectively. The rotation speed of the stage may be, for example, 500 rpm or higher and 4000 rpm or lower, the injection amount of the liquid may be, for example, 0.05 L / min or higher and 5.0 L / min or lower, and the injection time may be, for example, 5 seconds or longer and 300 seconds or shorter.

[0107] According to the method for manufacturing a semiconductor device of the first embodiment, since the protective layer 12 is superposed on the surface (circuit surface) of the semiconductor wafer W where the circuit components are formed, the circuit surface can be protected until the protective layer 12 is removed. Even if foreign matter adheres to the circuit surface before the protective layer 12 is superposed, when removing the small pieces 12' of the protective layer overlapping the circuit surface, the foreign matter can also be removed. Therefore, it is possible to suppress the adhesion of foreign matter to the circuit surface of the manufactured semiconductor chip X.

[0108] In the extraction step, the semiconductor wafer W or the semiconductor chip X is peeled off from the adhesive fixing layer 22 of the dicing tape 20. When performing the extraction step, it is necessary that the semiconductor wafer W or the semiconductor chip X can be easily peeled off from the adhesive fixing layer 22 of the dicing tape 20. The dicing tape 20 is designed to be able to exhibit such performance well. For example, the dicing tape 20 is configured such that when the active energy ray (for example, ultraviolet ray) is irradiated, the adhesive fixing layer 22 is cured and the adhesive force of the adhesive fixing layer 22 is reduced. Since the adhesive force of the adhesive fixing layer 22 can be reduced by curing the adhesive fixing layer 22 after irradiation, the semiconductor wafer W or the semiconductor chip X can be peeled off from the adhesive fixing layer 22 relatively easily after irradiation. The dicing tape 20 having such a configuration is commercially available.

[0109] The protective sheet and the method for manufacturing an electronic component device according to the embodiment of the present invention are as exemplified above, but the present invention is not limited to the protective sheet or the method for manufacturing an electronic component device exemplified above. That is, various forms used in a general protective sheet or a method for manufacturing an electronic component device can be adopted as long as the effects of the present invention are not impaired.

[0110] The matters disclosed by this specification include the following. (1) A protective sheet including a protective layer bonded to a surface of a substrate to be protected, wherein the protective layer contains a water-soluble compound, and the adhesive strength of the protective layer to the silicon wafer is 0.5 N / 10 mm or more. (2) The protective sheet according to (1) above, wherein the storage elastic modulus of the protective layer at 70°C is 50,000 Pa or less. (3) The protective layer contains a first water-soluble compound and a second water-soluble compound as the water-soluble compound, wherein the first water-soluble compound is a compound having a polyoxyethylene structure in the molecule, The second water-soluble compound is a water-soluble polyester resin having a mass average molecular weight of 2,000 or more. The protective sheet according to the above (1) or (2). (4) A method for manufacturing an electronic component device, including a temporary protection step of protecting a surface to be protected of a substrate with a protective sheet and then removing the protective sheet, The protective sheet includes a protective layer containing a water-soluble polymer compound and a base material layer overlapping one side of the protective layer. The adhesion of the protective layer to the silicon wafer is 0.5 N / 10 mm or more. The temporary protection step includes a first step of bonding the protective layer of the protective sheet to the surface to be protected and a second step of removing the protective sheet from the surface to be protected. The second step includes a step of peeling the base material layer from the protective layer and a step of removing the protective layer by dissolving at least a part of the protective layer with a liquid containing water. A method for manufacturing an electronic component device.

Example

[0111] Next, the present invention will be described in more detail by experimental examples, but the present invention is not limited thereto.

[0112] Each protective sheet (protective layer) of the example and the comparative example was produced as follows.

[0113] [Examples 1 to 3, Comparative Examples 1 to 3] [Raw materials for forming the protective layer] (First water-soluble compound) · P1-A Random copolymer of ethylene oxide and propylene oxide Product name "Alcox EP1010N" (manufactured by Meisei Chemical Industry Co., Ltd.) Mass average molecular weight: about 100,000 · P1-B Homopolymer of ethylene oxide Product name "Alcox R-150" (manufactured by Meisei Chemical Industry Co., Ltd.) Mass average molecular weight: about 100,000 ·P1-C Polyethylene glycol (purchased reagent) Average molecular weight: about 2000 ·P1-D Polyethylene glycol (purchased reagent) Average molecular weight: about 600 (Second water-soluble compound) ·P2-A Water-soluble polyester resin Product name "Plascote Z-221" (manufactured by Gohsei Chemical Co., Ltd.) having a sulfo group in the molecule Mass average molecular weight: about 14,000 (Other water-soluble compounds) ·PVA Polyvinyl alcohol Product name "JMR-3M" (manufactured by Nippon Vinyl Acetate - Poval Co., Ltd.) Mass average molecular weight: about 10,000

[0114] (Preparation of protective sheet) According to the compositions shown in Table 1, protective sheets were prepared respectively. Specifically, aqueous solutions of each polymer were prepared so that the total concentration of the polymers was 20% by mass according to the compounding compositions shown in Table 1. When preparing the aqueous solutions of each polymer, they were heated to 60 °C. The aqueous solutions of each polymer were respectively applied onto a release liner a (PET film with a thickness of 50 μm). The release liner a had a surface subjected to silicone release treatment, and the aqueous solution of the above polymer was applied onto this surface using an applicator. Next, a drying treatment was performed at 130 °C for 2 minutes to form a protective layer with a thickness of 5 μm overlapping one surface of the release liner a. Then, a release liner b (PET film with a thickness of 25 μm) was overlaid on the exposed surface of each protective layer. Note that the release liner b had a surface subjected to silicone release treatment, and this surface was pasted onto the protective layer. In this way, protective sheets each having a protective layer sandwiched between two release liners were prepared respectively.

[0115] (Shear storage modulus of the protective layer) According to the method described above, the shear storage modulus of each protective layer was measured. The results are shown in Table 1.

[0116] (Adhesion force of the protective layer to the silicon wafer) According to the method described above, the adhesion force of each protective layer to the silicon wafer was measured. The results are shown in Table 1.

[0117] [Table 1]

[0118] (Evaluation of embeddability) The embeddability of each protective sheet with respect to a semiconductor chip having a plurality of bump electrodes on one surface (hereinafter referred to as a semiconductor chip with bump electrodes) was evaluated. First, protective sheets of each example and each comparative example in a state where the release liner was attached only to one side were prepared. Next, a semiconductor chip with bump electrodes was fabricated as follows. Specifically, a plurality of regions (3 mm × 3 mm regions) in which a plurality of bump electrodes were arranged were formed on one surface of the semiconductor wafer body. In the above region, the diameter of the bump electrode (bump diameter) was 45 μm, the pitch between adjacent bump electrodes (bump pitch) was 150 μm, and the height from the surface of the semiconductor wafer body included in the semiconductor wafer to the tip of the bump electrode was 40 μm. The semiconductor wafer was cut into a planar dimension of 5 mm × 5 mm so that each semiconductor chip with bump electrodes had one of the plurality of above regions. Subsequently, the protective layer of each protective sheet was adhered to one surface of the semiconductor wafer body under the conditions of a pressure (lamination pressure) of 0.4 MPa and a roller temperature of 60°C. Then, the embeddability was evaluated according to the following criteria by observation with a digital microscope. The results are shown in Table 1 below. (Evaluation criteria) Excellent: No optical interference is confirmed. That is, the entire bump electrode is sufficiently embedded inside the protective layer. Good: Slight optical interference is confirmed in the outer peripheral portion of each bump electrode. That is, although the vicinity of the top of each bump electrode is sufficiently embedded inside the protective layer, the outer peripheral portion of each bump electrode is not sufficiently embedded. Defect: Obvious gaps are observed in the outer peripheral part of each bump electrode. That is, even near the top of each bump electrode, it is not sufficiently embedded inside the protective layer.

[0119] As can be understood from the above evaluation results, the protective layer of the example had good embedding property with respect to the adherend (substrate) having irregularities on the surface. Although not shown in the above results, in the removal process, the base material layer could be peeled off from the protective layer attached to the silicon wafer without accompanying the protective layer. Also, a plurality of small pieces of the protective layer could be removed relatively easily with water.

[0120] By manufacturing a semiconductor device or the like using the protective layer of the example as described above, a semiconductor device or the like provided with a semiconductor chip having almost no foreign matter attached can be efficiently manufactured.

Industrial Applicability

[0121] The method for manufacturing an electronic component device of the present invention is suitably used, for example, for manufacturing a semiconductor device having a semiconductor integrated circuit or the like.

Explanation of Reference Numerals

[0122] 1: Protective sheet 11: Base material layer, 11a: Support layer, 11b: Adhesive layer 12: Protective layer, 12’: Small piece of protective layer, 15: Release liner 20: Dicing tape 21: Underlayer, 22: Adhesive fixing layer W: Semiconductor wafer, X: Semiconductor chip

Claims

Claim 1 A protective sheet having a protective layer bonded to a surface to be protected of a substrate, wherein the protective layer contains a water-soluble compound, the storage elastic modulus of the protective layer at 70°C is 50,000 Pa or less, and the adhesive strength of the protective layer to a silicon wafer is 0.5 N / 10 mm or more. Claim 2 The protective layer contains a first water-soluble compound and a second water-soluble compound as the water-soluble compound, the first water-soluble compound is a compound having a polyoxyethylene structure in the molecule, and the second water-soluble compound is a water-soluble polyester resin having a mass average molecular weight of 2,000 or more. The protective sheet according to claim 1. Claim 3 A method for manufacturing an electronic component device, including a temporary protection step of protecting a surface to be protected of a substrate with a protective sheet and then removing the protective sheet, wherein the protective sheet includes a protective layer containing a water-soluble polymer compound and a base material layer overlapping one side of the protective layer, the adhesive strength of the protective layer to a silicon wafer is 0.5 N / 10 mm or more, the storage elastic modulus of the protective layer at 70°C is 50,000 Pa or less, the temporary protection step has a first step of bonding the protective layer of the protective sheet to the surface to be protected and a second step of removing the protective sheet from the surface to be protected, and the second step has a step of peeling the base material layer from the protective layer and a step of removing the protective layer by dissolving at least a part of the protective layer with a liquid containing water. A method for manufacturing an electronic component device.

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