Protective sheet and method for 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 to be attached to a surface of a substrate to be protected, for example, and to a method for manufacturing an electronic component device, including a step of removing the protective sheet after attaching the protective layer of the protective sheet to the surface of the substrate to be protected. [Background technology]

[0002] Protective sheets used in manufacturing electronic component devices have been known. These protective sheets include, for example, a protective layer that is attached to a surface of the electronic component device to be protected, and a base layer that is overlaid on one side of the protective layer.

[0003] This type of protective sheet is used, for example, during a process in a method for manufacturing an electronic component device. This type of manufacturing method for an electronic component device includes, for example, a step of mounting and temporarily fixing elements or the like as workpieces on one side of a substrate, a step of attaching a protective layer of the protective sheet to the other side (the surface to be protected) of the substrate, a step of processing the mounted elements or the like, a step of removing the elements or the like from the substrate, and a step of removing the protective layer from the substrate. For example, in this way, the protective sheet is once attached to the substrate and then removed from the substrate before use.

[0004] As a protective sheet used in the manufacturing method of the electronic component device described above, for example, a protective sheet comprising a base layer and a protective layer formed from a resin composition containing an oxyalkylene group-containing polyvinyl alcohol resin having a saponification degree of 55 mol% or less is known (e.g., Patent Document 1). The protective sheet described in Patent Document 1 can be used by attaching the protective layer to one surface (the surface to be protected) of a substrate. The base layer of the protective sheet described in Patent Document 1 has 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 furthermore, the protective layer can be removed with water after temporary fixing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-161735 Summary of the Invention [Problem to be solved by the invention]

[0007] However, with the protective sheet described in Patent Document 1, if the surface of the substrate to be protected is uneven due to bumps or the like, the protective layer may not be able to deform sufficiently in accordance with the unevenness, and part of the protective layer may not fit into the recesses. In other words, the embedding ability of the protective layer is not necessarily good. Furthermore, the protective sheet described in Patent Document 1 can be used by peeling the base layer from the protective layer before removing the protective layer with water, leaving only the protective layer on the surface of the substrate to be protected. Even when only the protective layer is attached to the surface to be protected without the base layer, there is also a method of use in which the protective layer is first covered with a covering tape and then the covering tape is peeled off. In such cases, when peeling the base layer or covering tape from the protective layer, the adhesion between the surface to be protected and the protective layer is relatively low, so part of the protective layer may adhere to the peeled base layer or covering tape. To prevent such problems, there is a demand for a protective sheet in which the embedding properties of the protective layer are good, the peel resistance of the protective layer attached to the surface to be protected is good, and the protective layer can be easily removed by a liquid containing water.

[0008] However, it cannot be said that sufficient research has yet been conducted into protective sheets that have good embedding properties for the protective layer, good peel resistance for the protective layer attached to the surface of the substrate to be protected, and that allow the protective layer to be easily removed by a liquid containing water.

[0009] Therefore, an object of the present invention is to provide a protective sheet that has good embedding properties for a protective layer, has good peel resistance for a protective layer attached to a surface of a substrate to be protected, and allows the protective layer to be easily removed by a liquid containing water, and also to provide a method for manufacturing an electronic component device using the above protective sheet. [Means for solving the problem]

[0010] In order to solve the above problems, the protective sheet of the present invention comprises: a protective layer attached to the surface of the substrate to be protected; the protective layer contains a water-soluble compound, The adhesive strength of the protective layer to the silicon wafer is 0.5 N / 10 mm or more.

[0011] The method for manufacturing an electronic component device according to the present invention includes: A method for manufacturing an electronic component device, comprising a temporary protection step of protecting a surface of a substrate to be protected with a protective sheet and then removing the protective sheet, the protective sheet comprises a protective layer containing a water-soluble polymer compound and a base layer overlying one side of the protective layer; the adhesive strength 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 dissolving at least a portion of the protective layer with a liquid containing water to remove the protective layer. [Effects of the Invention]

[0012] The protective sheet of the present invention has good embedding properties for the protective layer, good peel resistance for the protective layer attached to the surface of the substrate to be protected, and the protective layer can be easily removed with a liquid containing water. In the manufacturing method of the electronic component device according to the present invention, the above-mentioned protective sheet is used, so that the embedding property of the protective layer is good, the peel resistance of the protective layer attached to the surface of the substrate to be protected is good, and the protective sheet can be easily removed by a liquid containing water. [Brief explanation of the drawings]

[0013] [Figure 1A] 1 is a schematic cross-sectional view of an example of a protective sheet according to an embodiment of the present invention cut in the thickness direction. [Figure 1B] FIG. 4 is a schematic cross-sectional view of another example of the protective sheet of the present embodiment cut in the thickness direction. [Figure 1C] FIG. 4 is a schematic cross-sectional view of another example of the protective sheet of the present embodiment cut in the thickness direction. [Figure 2] FIG. 1 is a schematic cross-sectional view showing an example of a semiconductor wafer as a substrate. [Figure 3A] FIG. 10 is a schematic cross-sectional view showing the state of the substrate after the surface to be protected has been protected by the example of the protective sheet. [Figure 3B] FIG. 4 is a schematic cross-sectional view showing an example of peeling the base layer from the protective layer. [Figure 3C] FIG. 10 is a schematic cross-sectional view showing an example of a state after the base layer is removed and the protective layer is broken into small pieces. [Figure 3D] FIG. 4 is a schematic cross-sectional view showing an example of a state after a laminate of a protective layer and a substrate is cut into small pieces. [Figure 3E] 5A and 5B are schematic cross-sectional views showing an example of how small pieces of the protective layer are removed from the substrate. [Figure 3F] 5A and 5B are schematic cross-sectional views showing an example of how a small piece of the protective layer is removed from a small piece of the substrate. [Figure 4A] 3 is a schematic cross-sectional view showing the state after the surface to be protected (circuit surface) of the semiconductor wafer has been protected by an example of a protective sheet. FIG. [Figure 4B] FIG. 10 is a schematic cross-sectional view showing a state in which a grinding process is carried out using an example of a protection sheet. [Figure 4C] FIG. 2 is a schematic cross-sectional view showing the state after the first step (attaching step) has been carried out using an example of a protective sheet. [Figure 4D]FIG. 10 is a schematic cross-sectional view showing the peeling step of the second step (removal step) performed using an example of a protective sheet. [Figure 4E] FIG. 3 is a schematic cross-sectional view showing an example of how the protective layer of the protective sheet is broken into small pieces. [Figure 4F] FIG. 10 is a schematic cross-sectional view showing another example of how the protective layer of the protective sheet is broken into small pieces. [Figure 4G] FIG. 10 is a schematic cross-sectional view showing another example of how the protective layer of the protective sheet is broken into small pieces. [Figure 4H] FIG. 4 is a schematic cross-sectional view illustrating the removal of the protective layer of the protective sheet by the dissolving step in the second step (removal step). [Figure 4I] FIG. 10 is a schematic cross-sectional view illustrating a modified example of how the protective layer of the protective sheet is removed by the dissolving step in the second step (removal step). DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments 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. It should be noted that the figures in the drawings are schematic diagrams and the aspect ratios are not necessarily the same as those of the actual product.

[0015] As shown in each of FIGS. 1A to 1C, the protective sheet 1 of this embodiment includes at least a protective layer 12 containing a water-soluble polymer compound. The protective sheet 1 of this embodiment may further include a base layer 11 overlying one side of the protective layer 12, as shown in each of FIGS. 1A and 1B. The base layer 11 may include an adhesive layer 11b overlying one side of the protective layer 12 and a support layer 11a overlying the adhesive layer 11b, as shown in FIG. 1A. Alternatively, the base layer 11 may include only the support layer 11a, as shown in FIG. 1B. The protective sheet 1 of this embodiment may also include two release liners 15 overlying both sides of the protective layer 12, as shown in FIG. 1C.

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

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

[0018] Specifically, examples of the substrate to be adhered include a semiconductor wafer for obtaining semiconductor chips, semiconductor chips obtained by cutting a semiconductor wafer into small pieces, a linked circuit board formed by linking multiple circuit boards, a circuit board, etc. The surface to be protected of these substrates usually has irregularities.

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

[0020] The semiconductor wafer W is diced (divided) into small semiconductor chips, for example, along a cutting line D shown in Fig. 2. Fig. 2 shows the cutting line D for obtaining semiconductor chips having one electrode portion W2. Each semiconductor chip has at least one electrode portion W2.

[0021] The electrode portion W2 of the semiconductor chip is electrically connected to the electrode portion of another member, such as a circuit board or another semiconductor chip configured similarly to the semiconductor chip described above. For example, a semiconductor chip may have a pair of electrodes arranged on both sides of the semiconductor chip body, and a conductive portion that penetrates the semiconductor chip body in the thickness direction to electrically connect the pair of electrodes. This type of semiconductor chip is called a TSV (Through Silicon Via) type. The electrodes are electrically connected to other components. In a TSV type semiconductor chip, only one side may be a circuit surface, or both sides may be circuit surfaces. In a TSV type semiconductor chip, since electrodes can be formed on both sides, both sides of the semiconductor chip can be surfaces to be protected.

[0022] The semiconductor chip may be a sensor chip having a sensor element (for example, a light receiving element or a vibration element), etc. The sensor chip may be, for example, a CMOS (Complementary Metal-Oxide Semiconductor) chip.

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

[0024] The above-mentioned electronic component assembly may also be, for example, a pseudo wafer. The pseudo wafer may have, for example, a support substrate and a package formed by resin-sealing a plurality of semiconductor chips arranged on one surface of the support substrate. The pseudo wafer may be only the package 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 may be used to protect the rewiring layer. Note that a divided body obtained by dividing the above-mentioned pseudo wafer so as to include at least one semiconductor chip may be a substrate.

[0025] Protective layer 12 has adhesiveness that allows it to adhere closely to the surface of the substrate to be protected, which is the adherend. By bonding protective layer 12 of 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 protective layer 12 that overlaps the surface to be protected is removed. Furthermore, the protective layer 12 can deform to accommodate the unevenness of the surface to be protected, and therefore can fully fill recesses, providing excellent embedding properties. Furthermore, after protection sheet 1 has been used to temporarily protect a surface to be protected, for example as described above, it can be easily removed with a liquid including water. The method of using protective sheet 1, in which protective layer 12 of protective sheet 1 is attached to a substrate as an adherend, will be described in detail later.

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

[0027] The thickness of the base 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 5 μm or more. Also, such a thickness may be 40 μm or less. Note that when the base layer 11 is a laminate, the above thickness is the total thickness of the laminate.

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

[0029] The resin contained in the support layer 11a may be a resin having a polar group. When the support layer 11a contains a resin having a polar group, the wettability of the surface of the support layer 11a is improved. In other words, the surface free energy of the support layer 11a can be increased. It is preferable that the wettability of the surface of the support layer 11a is relatively high, since this can improve the adhesion between the support layer 11a and the adhesive layer 11b or the protective layer 12.

[0030] Examples of the resin having a polar group include polyester resin (PET, etc.), polyimide resin, polyamide-imide resin, etc. As such a resin, at least one of polyimide resin and polyester resin is preferred. For example, the support layer 11a may be a polyimide resin film, a polyamide-imide resin film, or 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 base material layer) The adhesive layer 11b has, for example, pressure-sensitive adhesive properties and contains, for example, at least an acrylic resin, which will be described in detail later.

[0033] The adhesive layer 11b may have a substantially non-reactive structure. This type of adhesive layer 11b may contain, for example, an acrylic resin and an isocyanate compound. In this case, the acrylic resin may not 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 so that a curing reaction proceeds when irradiated with active energy rays (such as ultraviolet rays), thereby reducing the adhesive strength. This type of adhesive layer 11b may contain, for example, an acrylic resin, an isocyanate compound, and a polymerization initiator (such as a photopolymerization initiator).

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

[0036] The structural unit of the alkyl (meth)acrylate is derived from an alkyl (meth)acrylate monomer. In other words, the molecular structure obtained after the polymerization reaction of the alkyl (meth)acrylate monomer is the structural unit of the alkyl (meth)acrylate. The term "alkyl" refers to a 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 alkyl(meth)acrylate include 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, and isooctyl(meth)acrylate. Examples of structural units include 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, and eicosyl(meth)acrylate.

[0038] The above acrylic resin has a hydroxyl group-containing (meth)acrylate structural unit, and the hydroxyl group of such a structural unit easily reacts with an isocyanate group. By allowing the acrylic resin having a hydroxyl group-containing (meth)acrylate structural unit and the isocyanate compound to coexist in the adhesive layer 11b, the adhesive layer 11b can be appropriately cured. As a result, the adhesive layer 11b can be sufficiently gelled. As a result, the adhesive layer 11b can exhibit adhesive properties 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 term "C2-C4 alkyl" refers to the hydrocarbon moiety ester-bonded to (meth)acrylic acid and its carbon number. In other words, a hydroxyl group-containing C2-C4 alkyl (meth)acrylate monomer refers to a monomer in which (meth)acrylic acid is ester-bonded to an alcohol (usually a dihydric alcohol) having 2 to 4 carbon atoms. The hydrocarbon moiety of the C2-C4 alkyl is usually a saturated hydrocarbon.

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

[0041] The acrylic resin contains a structural unit of a polymerizable group-containing (meth)acrylate having a polymerizable unsaturated double bond in the side chain. When the acrylic resin contains a polymerizable group-containing (meth)acrylate structural unit, radicals are generated from the photopolymerization initiator by irradiation with active energy rays such as ultraviolet rays, and the action of these radicals causes a crosslinking reaction between the acrylic resins. As a result, the adhesive strength of the adhesive layer 11b can be reduced by irradiation. The active energy rays include ultraviolet rays, radioactive rays, and electron beams.

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

[0043] The structural unit of the polymerizable group-containing (meth)acrylate having a polymerizable 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 urethane reaction, thereby obtaining the structural unit of the polymerizable group-containing (meth)acrylate.

[0044] The isocyanate group-containing (meth)acrylate monomer preferably has one isocyanate group and one (meth)acryloyl group in the molecule, such as 2-isocyanatoethyl (meth)acrylate.

[0045] The adhesive layer 11b may further contain an isocyanate compound, part of which may be in a state after reaction such as urethane reaction. The isocyanate compound has a plurality of isocyanate groups in the molecule, which allows the cross-linking reaction between the acrylic resins in the adhesive layer 11b to proceed.

[0046] Examples of the isocyanate compound include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and araliphatic diisocyanates. Further, examples of the isocyanate compound include polymerized polyisocyanates such as diisocyanate dimers and trimers, and polymethylene polyphenylene polyisocyanates. 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 applying heat or light energy. When the adhesive layer 11b contains a polymerization initiator, a cross-linking reaction between the acrylic resins can be promoted when heat energy or light energy is applied to the adhesive layer 11b, and the adhesive layer 11b can be cured. This reduces the adhesive strength of the adhesive layer 11b, and allows the protective layer 12 and the cured adhesive layer 11b to be easily peeled off. As the polymerization initiator, for example, a commercially available general photopolymerization initiator or thermal polymerization initiator is used.

[0048] The adhesive layer 11b may further contain additives such as antioxidants, ultraviolet absorbers, and 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 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 even more preferably 99% by mass or more. This allows the protective layer 12 to 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 its 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 such water solubility that when a thin film (thickness of 50 μm or less) of each water-soluble polymer compound is immersed in water at 40° C., it is completely dissolved.

[0053] The protective layer 12 has a predetermined level of hydrophilicity or more. When the protective layer 12 has a predetermined level of hydrophilicity or more, typically, at least a portion of the protective layer 12 dissolves in a liquid containing water. Because the protective layer 12 has a predetermined level of hydrophilicity or more, it is configured so that at least a portion of the protective layer 12 dissolves and is removed from the surface of the substrate when it comes into contact with a liquid containing water.

[0054] The adhesive strength of the protective layer 12 to the silicon wafer is 0.5 [N / 10 mm] or more. Such 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. By increasing the adhesive strength of the protective layer 12 to the silicon wafer, the protective layer 12 bonded to the surface of the substrate to be protected is more effectively prevented from being peeled off together with the base layer 11 when the base layer 11 overlapping the protective layer 12 is peeled off from the protective layer 12. Furthermore, unintentional exposure of the surface of the protected silicon wafer can be more effectively prevented. The adhesive strength of the protective layer 12 to the silicon wafer may be 10.0 [N / 10 mm] or less.

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

[0056] The adhesion of protective layer 12 to a silicon wafer (bare silicon wafer) is measured under the following conditions. Although a protective sheet 1 having the configuration shown in Figure 1C will be used as a specific example, the adhesion is measured in the same manner for protective sheet 1 having the configuration shown in Figure 1A or 1B. 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 attached to the exposed surface to obtain a first test piece. The backing tape is attached using a hand roller at a temperature of 25°C. Next, the first test piece is cut to a width of 100 mm, and the other release liner is peeled off from the protective layer 12 to expose the other side of the protective layer 12. This exposed surface is then bonded to a bare wafer to obtain a second test piece (measurement sample). Bonding to the bare wafer is performed using a 2 kg standard roller (manual adhesion test press wheel adhesive tape adhesion tester) at a temperature of 90°C and a speed of 10 mm / sec. After bonding, the test piece is allowed to cool naturally (cool down) for at least 20 minutes. Next, the protective layer 12 and backing tape are peeled from the bare wafer at a temperature of 23°C, a peel angle of 180°, and a peel speed of 300 mm / min, and the peel strength of the measurement sample is measured. The measured peel strength is defined as the adhesion strength. An autograph (manufactured by Shimadzu Corporation) can be used as the measurement device.

[0057] The storage 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 modulus of the protective layer 12 at 70°C is 100,000 Pa or less, sufficient embedding properties can be exhibited even when the temperature when the protective layer 12 is attached to the surface to be protected is relatively low. The storage modulus of the protective layer 12 at 70° C. may be 10,000 Pa or more.

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

[0059] The storage modulus (shear storage modulus) of the protective layer 12 is measured as follows. Specifically, in measuring the storage viscoelasticity of the protective layer 12, a protective layer is laminated as necessary to prepare a sheet-like measurement sample with a thickness of 250 μm to 350 μm. A test piece is prepared by punching out the measurement sample with an 8 mm diameter punch. Then, measurement is performed under the following measurement conditions, and the measured value of the storage modulus (G') [Pa] at 70°C is read. Measuring device: Rheometer (For example, HAAKE's "MARS III") Measurement temperature: 40°C to 100°C (heating rate 10°C / min) Measurement frequency: 1Hz (1 / sec) Strain: 5% Measurement gap: 0.250 mm Measurement mode: Shear mode Measurement terminal: Parallel plate with a measurement surface diameter of 8 mm

[0060] In the 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 5 μm or more. Alternatively, 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 its molecule. The polyoxyethylene structure acts as a hydrophilic group. When the first water-soluble compound has a polyoxyethylene structure as a hydrophilic group in its molecule, it can be more easily soluble in a liquid containing water even at room temperature.

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

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

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

[0065] The mass average molecular weight Mw of the polyethylene oxide (PEO) is preferably 200,000 (two hundred thousand) or less. By having a mass average molecular weight Mw of 200,000 or less, the first water-soluble compound can have a sufficiently low softening point. This can improve the adhesion of the protective layer 12 to the surface to be protected. Furthermore, the protective layer 12 can be efficiently removed from the surface to be protected in a shorter time using a liquid containing water. The mass average molecular weight Mw may be, for example, 50,000 or more.

[0066] As the first water-soluble compound, such as polyethylene glycol (PEG), polyethylene oxide (PEO), or polyalkylene oxide copolymer, 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 condensation product 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 the form of a salt.

[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 room temperature (23±2°C) water is sprayed onto the entire surface of a 20 μm-thick thin film made of water-soluble polyester at a spray pressure of 0.005 MPa for 20 minutes, the entire thin film dissolves in water. (B) When 50°C water is sprayed onto the entire surface of a 20 μm-thick thin film made of water-soluble polyester at a spray pressure of 0.005 MPa for 10 minutes, the entire thin film dissolves in water. (C) A water-soluble polyester powder is mixed with room temperature water in a mass ratio of powder:water = 1:5 to obtain a mixed liquid, and when the mixed liquid is irradiated with ultrasound for 20 minutes, the water-soluble polyester powder is completely dissolved in the water. (D) A water-soluble polyester powder is mixed with 50°C water in a mass ratio of powder:water = 1:5 to obtain a mixed solution, and when the mixed solution is irradiated with ultrasound for 10 minutes, all of the water-soluble polyester powder dissolves in the water.

[0069] The mass average molecular weight Mw of the water-soluble polyester resin may be 5,000 or more, 7,000 or more, or 10,000 or more. The mass average molecular weight Mw of the water-soluble polyester resin is preferably 40,000 (40,000) or less, more preferably 30,000 (30,000) or less, even more preferably 20,000 (20,000) 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, the protective layer 12 can be easily formed into a film, and the embedding properties of the protective layer 12 can be improved. Furthermore, the protective layer 12 can more sufficiently prevent fine foreign matter from adhering to the surface to be protected. Furthermore, the protective layer 12 can be 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 specified 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] The protective layer 12 of this embodiment may further contain, in addition to the above-mentioned ingredients, a surfactant, a plasticizer, and the like.

[0073] The protective layer 12 has adhesiveness that allows it to adhere to the surface of the substrate to be protected. When the base layer 11 has only the support layer 11a, the protective layer 12 has adhesiveness that allows it to adhere to the support layer 11a. When the base layer 11 has the support layer 11a and the adhesive layer 11b, the protective layer 12 and the adhesive layer 11b are in contact with each other, so the protective layer 12 has adhesiveness that allows it to adhere to the adhesive layer 11b.

[0074] 1B, the protective sheet 1 of this embodiment may include a release liner 15 that covers one side of the protective layer 12 (the side of the protective layer 12 that is not overlapping with the base layer 11) before use. The release liner 15 is used to protect the protective layer 12 and is peeled off immediately before the protective layer 12 is attached to, for example, a substrate.

[0075] The protective sheet 1 of this embodiment can be produced by a general method, for example, as follows. First, a water-soluble polymer compound is dissolved in a solvent containing water. Heating may be used during dissolution. 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 any ratio is preferred. Examples of such aqueous organic solvents include methanol, ethanol, and isopropyl alcohol. Next, the polymer solution prepared as described above is applied (coated) to the base layer 11 or the release liner 15. After application, the solution is heated at a temperature at which the solvent volatilizes, thereby forming the protective layer 12 superimposed on the base layer 11 or the release liner 15. Although the protective sheet 1 can be produced in this manner, the method for producing the protective sheet is not limited to the above-mentioned example method.

[0076] The protective sheet 1 is used, for example, as an auxiliary tool for manufacturing an electronic component device. The protective sheet 1 is used, for example, temporarily during the process of manufacturing the 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 having a semiconductor chip, a device having a system LSI having a complementary MOS (CMOS), or a device having a device (MEMS Micro Electro Mechanical Systems) in which mechanical elements, sensors, actuators, or electronic circuits are integrated by microfabrication technology on a single silicon substrate, glass substrate, organic material substrate, etc. The manufactured electronic component device may also be a device having a circuit board.

[0078] Various substrates can be used as the substrate to which protective layer 12 of protective sheet 1 of this embodiment is attached. As described above, examples of the substrate include a semiconductor wafer, a circuit board, or a linked circuit board (such as a pseudo wafer) formed by connecting multiple circuit boards.

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

[0080] The method for manufacturing an electronic component device according to this embodiment includes the steps of: A method for manufacturing an electronic component device, comprising a temporary protection step of protecting a surface of a substrate to be protected with a protective sheet and then removing the protective sheet, the protective sheet comprises a protective layer containing a water-soluble polymer compound and a base layer overlying one side of the protective layer; the adhesive strength of the protective layer to the silicon wafer is 0.5 N / 10 mm or more; the temporary protection step includes a first step (hereinafter also referred to as an attachment step) of attaching the protective layer of the protective sheet to the surface to be protected, and a second step (hereinafter also referred to as a removal step) of removing the protective sheet from the surface to be protected, The second step (removal step) includes a step of peeling the base material layer from the protective layer (hereinafter also referred to as a peeling step), and a step of dissolving at least a portion of the protective layer with a liquid containing water to remove the protective layer (hereinafter also referred to as a dissolving step).

[0081] In the temporary protection step, for example, as shown in Fig. 3A, a protective sheet 1 having a base layer 11 on one side of a protective layer 12 may be used in the attachment step, and the protective layer 12 of the protective sheet 1 may be attached to the surface to be protected of the substrate S, thereby protecting the surface to be protected of the substrate S. Thereafter, in the peeling step, the base layer 11 is peeled off from the protective layer 12, for example, as shown in Fig. 3B.

[0082] The manufacturing method of the electronic component device of this embodiment may further include a step of dividing at least the protective layer 12 into small pieces to produce multiple protective layer small pieces 12' (hereinafter also referred to as a small piece process), as shown in Figures 3C and 3D, respectively. In the dicing step, for example, as shown in Fig. 3C, only the protective layer 12 of the stack of overlapping substrates S and protective layers 12 may be divided into small pieces to produce a plurality of small pieces 12'. On the other hand, for example, as shown in Fig. 3D, for example, a stack of overlapping substrates S and protective layers 12 may be divided into small pieces to produce a plurality of stacked small pieces of chips S' formed by dicing the substrate and small pieces 12' of the protective layer overlapping each other.

[0083] In the above-mentioned temporary protection process, the dissolution process removes each small piece 12' of the protective layer overlapping the surface to be protected of the substrate S (such as the circuit surface of the chip S') using a liquid containing water, as shown in, for example, Figure 3E or Figure 3F.

[0084] In the method for manufacturing an electronic component device according to this embodiment, at least one surface of the substrate is protected by a protective layer 12. The surface to be protected (the surface to be protected) may be only one surface of the substrate or may be both surfaces. Circuit components (described in detail below) may or may not be arranged on the surface to be protected.

[0085] The substrate may be made of any material, as long as it is plate-shaped. Examples of the substrate material include glass, silicon, stainless steel (SUS), plastic, and ceramic. Examples of the substrate include a semiconductor wafer, a sensor wafer such as a CMOS or MEMS, a pseudo wafer, and a circuit board.

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

[0087] Hereinafter, a detailed description will be given of an example in which a semiconductor device (semiconductor integrated circuit) is manufactured as an electronic component device.

[0088] Generally, a method for manufacturing a semiconductor device includes a front-end process in which a circuit surface is formed on one side of a bare wafer using highly integrated electronic circuits, and a back-end process in which chips are cut out from the semiconductor wafer on which the circuit surface has been formed and assembled.

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

[0090] In the subsequent process, at least a temporary protection process is carried out, for example, including a bonding process for bonding the protective layer 12 of the protective sheet 1 to the surface to be protected (circuit surface) of the semiconductor wafer W as a substrate, and a removal process for removing the protective layer 12 bonded to the surface to be protected (circuit surface). If necessary, between the above-mentioned attachment step and removal step, a grinding step may be carried out in which the semiconductor wafer with the protective sheet 1 attached thereto is subjected to a grinding process to reduce the thickness of the semiconductor wafer. The removal process includes a peeling process in which the base material layer 11 is peeled off from the protective layer 12 bonded to the circuit surface of the semiconductor wafer W, and a dissolving process in which at least a portion of the protective layer 12 is dissolved with a liquid containing water to remove the protective layer 12 bonded to the circuit surface of the semiconductor wafer W. If necessary, a laser grouping process (described in detail later) or a plasma dicing process (described in detail later) of the semiconductor wafer W may be carried out between the peeling step and the dissolving step. When the dissolving step is performed, the protective layer 12 may be fragmented in a fragmenting step. In other words, in the dissolving step, fragmented protective layer pieces 12′ may be removed using a liquid containing water.

[0091] The above-described post-processing includes, for example, the above-described attaching step, the above-described grinding step performed as needed, a mounting step in which the surface of the semiconductor wafer opposite the circuit surface is attached to the adhesive fixing layer 22 of the dicing tape 20 to fix the semiconductor wafer, a peeling step in the above-described removing step, a dicing step performed as needed in which at least the protective layer 12 is diced into small pieces, a dissolving step in the above-described removing step, and a removal step in which the semiconductor wafer W or semiconductor chip is peeled off and removed from the adhesive fixing layer 22 of the dicing tape 20. A semiconductor integrated circuit (semiconductor device) is manufactured through, for example, these steps.

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

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

[0094] The grinding process is carried out as necessary. For example, with the semiconductor wafer W, protective layer 12, and base layer 11 stacked, grinding is performed on the surface of the semiconductor wafer W on which no circuit components are arranged. More specifically, as shown in FIG. 4B , grinding (back grinding) is performed using a grinding pad K until the semiconductor wafer W reaches a predetermined thickness. The grinding process reduces the thickness of the semiconductor wafer W to the predetermined thickness.

[0095] In the mounting step, as shown in FIG. 4C, the semiconductor wafer W is attached and fixed to the adhesive fixing layer 22 of the dicing tape 20 while the dicing ring R is attached to the adhesive fixing layer 22 of the dicing tape 20. In addition, if the above-mentioned grinding process is not performed, the attachment process of the temporary protection process may be performed by attaching and fixing the semiconductor wafer W to the adhesive fixing layer 22 of the dicing tape 20, and then superimposing the protective layer 12 on the surface to be protected (circuit surface) of the semiconductor wafer W.

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

[0097] After the peeling step, a dicing step is carried out as necessary to diced at least the protective layer 12. For example, the protective layer 12 and the semiconductor wafer W may be diced into semiconductor chips (dies) by laser grouping and plasma dicing of the semiconductor wafer W.

[0098] In the dicing step, as shown in FIG. 4E or FIG. 4F, for example, only the protective layer 12 or both the protective layer 12 and the semiconductor wafer W are diced. In laser grouping, as shown in FIG. 4E, the circuit surface is protected by a protective layer 12 while being irradiated with laser light L. For example, laser grouping can be performed when the circuit surface contains an insulating film known as a low-k film, which has a lower dielectric constant than SiO2. The wiring layer containing the low-k film is removed with the laser light, forming two narrow grooves spaced apart within the dicing street. The semiconductor wafer W can then be diced into smaller pieces by subsequent plasma dicing. In the laser grouping process, foreign matter such as fragments of the insulating film may be generated due to 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 prevent the foreign matter from adhering to the surface to be protected.

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

[0100] 4G, in the dicing step, the semiconductor wafer W with the protective layer 12 attached thereto may be fixed on the adhesive fixing layer 22 of the dicing tape 20, and an expanding operation may be performed to stretch the dicing tape 20 in the planar direction so as to increase the surface area of ​​the dicing tape 20. This may divide the laminate of the semiconductor wafer W and the protective layer 12 into small pieces, and further may widen the gaps between adjacent semiconductor chips X formed by the dicing in the planar direction. The semiconductor wafer W needs to be divided into small pieces by the above-mentioned expanding operation. Therefore, the semiconductor wafer W to be divided into small pieces as described above is designed to be easily cleaved. For example, a weak portion is formed inside the semiconductor wafer W for dividing into semiconductor chips X (dies). The weak portion can be formed by irradiating the semiconductor wafer W with laser light using a commercially available stealth dicing device. The protective layer 12 also needs to be divided into small pieces by the above-mentioned expanding operation, and is therefore designed to be easily cleaved.

[0101] Details of the above-mentioned expanding operation are as follows. For example, as shown in FIG. 4G, after a dicing ring R is attached to the adhesive fixing layer 22 of the dicing tape 20, the dicing ring R is fixed to a holder H of an expanding device. A push-up member U provided in the expanding device is pushed up from below the dicing tape 20, stretching the dicing tape 20 so that it spreads in the surface direction. This causes the semiconductor wafer W and protective layer 12 to be broken into small pieces under specific temperature conditions. The above-mentioned temperature conditions are, for example, -20°C or higher and 0°C or lower. The expanded state is released by lowering the push-up member U (this is the low-temperature expanding operation). 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 expand the surface area of ​​the dicing tape 20. This causes the adjacent semiconductor chips X to be separated in the surface direction of the dicing tape 20, further widening the kerf (gap) (room temperature expanding operation). By stretching the dicing tape 20 in the planar direction so as to increase the area of ​​the dicing tape 20, the semiconductor wafer W can be divided into small semiconductor chips X along the boundaries of the fragile portions inside the semiconductor wafer. At this time, as the semiconductor wafer W is divided into small semiconductor chips X, the protective layer 12 is also divided into small pieces.

[0102] In the dissolution step of the removal process, for example as shown in Figure 4H or Figure 4I, a liquid containing water is brought into contact with multiple small pieces 12' of the protective layer, and at least a portion of each small piece 12' is dissolved by the liquid, thereby removing each small piece 12' of the protective layer from the surface (surface to be protected) of the semiconductor wafer W or semiconductor chip X. By removing the protective layer pieces 12' in this manner, all of the multiple protective layer pieces 12' can be removed relatively easily, and the number of foreign substances attached to the surface to be protected can be reduced relatively easily using the above-mentioned liquid. Also, the surface of the semiconductor wafer W on which the protective layer 12 was overlaid (the surface to be protected), or the surface of each semiconductor chip X on which the protective layer pieces 12' were overlaid (the surface to be protected) can be cleaned with a liquid.

[0103] In the dissolving step of the removal process, at least a portion of the fragmented protective layer (the plurality of small pieces 12' of the protective layer) is dissolved by the liquid. As a result, the adhesive strength of the small pieces 12' of the protective layer to the semiconductor chip X weakens, and the small pieces 12' of the protective layer become more easily peeled off from the semiconductor chip X. This allows the plurality of small pieces 12' of the protective layer to be removed relatively easily.

[0104] The water-containing liquid is not particularly limited as long as it is a liquid substance containing water, and may contain 30% by mass or more of water, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more of water. The liquid may contain, in addition to water, a component that dissolves in water. Examples of such components include water-soluble organic solvents. Examples of such water-soluble organic solvents include monohydric alcohols having four or fewer carbon atoms, such as methanol, ethanol, propanols such as isopropyl alcohol, and butanols such as t-butanol.

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

[0106] For example, in the dissolving step of the removal process, the liquid is sprayed toward the semiconductor wafer W attached to the dicing tape 20 or the semiconductor chips X attached to the dicing tape 20 while rotating a disk-shaped stage supporting the dicing tape 20 from below in the circumferential direction. This makes it possible to remove multiple small pieces 12' of the protective layer overlapping the semiconductor wafer W or the semiconductor chips X, respectively. The rotation speed of the stage may be, for example, 500 rpm or more and 4000 rpm or less, the amount of liquid sprayed may be, for example, 0.05 L / min or more and 5.0 L / min or less, and the spraying time may be, for example, 5 seconds or more and 300 seconds or less.

[0107] According to the semiconductor device manufacturing method of the first embodiment, the protective layer 12 is overlaid on the surface (circuit surface) of the semiconductor wafer W on which the circuit components are formed, so that the circuit surface can be protected until the protective layer 12 is removed. Even if foreign matter is attached to the circuit surface before the protective layer 12 is overlaid, the foreign matter can be removed when the small pieces 12' of the protective layer overlaid on the circuit surface are removed. Therefore, it is possible to prevent foreign matter from adhering to the circuit surface of the semiconductor chip X to be manufactured.

[0108] In the removal step, the semiconductor wafer W or semiconductor chip X is peeled off from the adhesive fixing layer 22 of the dicing tape 20. When performing the removal step, the semiconductor wafer W or semiconductor chip X needs to 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 this performance well. For example, the dicing tape 20 is configured so that, when irradiated with active energy rays (e.g., ultraviolet rays), the adhesive fixing layer 22 hardens and the adhesive strength of the adhesive fixing layer 22 decreases. Since the adhesive fixing layer 22 hardens after irradiation, the adhesive strength of the adhesive fixing layer 22 can be reduced, and therefore the semiconductor wafer W or semiconductor chip X can be relatively easily peeled off from the adhesive fixing layer 22 after irradiation. Dicing tapes 20 configured in this way are 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 of general protective sheets or those used in the manufacturing method of electronic component devices can be employed as long as they do not impair the effects of the present invention.

[0110] The matters disclosed by this specification include the following. (1) a protective layer attached to the surface of the substrate to be protected; the protective layer contains a water-soluble compound, A protective sheet, wherein 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 protective layer has a storage modulus at 70°C of 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 compounds, the first water-soluble compound is a compound having a polyoxyethylene structure in its 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 (1) or (2) above. (4) A method for manufacturing an electronic component device, comprising a temporary protection step of protecting a surface of a substrate to be protected with a protective sheet and then removing the protective sheet, the protective sheet comprises a protective layer containing a water-soluble polymer compound and a base layer overlying one side of the protective layer; the adhesive strength 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 method for manufacturing an electronic component device, wherein the second step includes a step of peeling the base material layer from the protective layer, and a step of dissolving at least a portion of the protective layer using a liquid containing water to remove the protective layer. [Example]

[0111] The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these examples.

[0112] Each protective sheet (protective layer) of the Examples and Comparative Examples was prepared 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: Approximately 100,000 P1-B Ethylene oxide homopolymer Product name: Alcox R-150 (manufactured by Meisei Chemical Industry Co., Ltd.) Mass average molecular weight: Approximately 100,000 P1-C Polyethylene glycol (purchased reagent) Average molecular weight: approx. 2000 P1-D Polyethylene glycol (purchased reagent) Average molecular weight: about 600 (Second water-soluble compound) P2-A Water-soluble polyester resin Product name: "Plascoat Z-221" (manufactured by Goo Chemical Co., Ltd.) Contains a sulfo group in the molecule Mass average molecular weight: approx. 14,000 (Other water-soluble compounds) PVA Polyvinyl alcohol Product name: "JMR-3M" (manufactured by Japan Vinyl Acetate & Poval Co., Ltd.) Mass average molecular weight: approx. 10,000

[0114] (Preparation of protective sheet) Protective sheets were prepared according to the compositions shown in Table 1. Specifically, aqueous solutions of each polymer were prepared so that the total polymer concentration was 20% by mass using the blending compositions shown in Table 1. When preparing the aqueous solutions of each polymer, the solution was heated to 60°C. Each aqueous solution of each polymer was applied to release liner a (PET film, 50 μm thick). Release liner a had a surface that had been treated with a silicone release agent, and the aqueous polymer solution was applied to this surface using an applicator. This was then dried at 130°C for 2 minutes to form a 5 μm-thick protective layer that overlapped one side of release liner a. Release liner b (PET film, 25 μm thick) was then superimposed on the exposed surface of each protective layer. Release liner b had a surface that had been treated with a silicone release agent, and this surface was attached to the protective layer. In this way, protective sheets comprising a protective layer sandwiched between two release liners were prepared.

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

[0116] (Peeling force of protective layer against bare silicon wafer) The peel strength of each protective layer against a bare silicon wafer was measured according to the method described above. The results are shown in Table 1.

[0117] [Table 1]

[0118] <Evaluation of embeddability> The embeddability of each protective sheet in 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, a protective sheet of each example and comparative example was prepared with a release liner attached to only one side. Next, semiconductor chips with bump electrodes were fabricated as follows. Specifically, multiple regions (3 mm x 3 mm regions) in which multiple bump electrodes were arranged were formed on one surface of the semiconductor wafer body. In these regions, the diameter of the bump electrodes (bump diameter) was 45 μm, the spacing between adjacent bump electrodes (bump pitch) was 150 μm, and the height from the surface of the semiconductor wafer body provided on the semiconductor wafer to the tip of the bump electrode was 40 μm. The semiconductor wafer was cut to planar dimensions of 5 mm x 5 mm so that each semiconductor chip with bump electrodes had one of the multiple regions. Subsequently, the protective layer of each protective sheet was adhered to one surface of the semiconductor wafer body under conditions of a pressure (laminating pressure) of 0.4 MPa and a roller temperature of 60°C. The embeddability was then evaluated by observation using a digital microscope according to the following criteria. The results are shown in Table 1 below. (Evaluation criteria) Excellent: No optical interference was observed. In other words, each bump electrode was fully embedded in its entirety within the protective layer. Good: Some optical interference was observed around the periphery of each bump electrode. In other words, the top of each bump electrode was sufficiently embedded in the protective layer, but the periphery of each bump electrode was not sufficiently embedded. Poor: Clear voids are observed around the periphery of each bump electrode. In other words, even the top of each bump electrode is not fully embedded in the protective layer.

[0119] As can be seen from the above evaluation results, the protective layers of the examples had good embedding properties for adherends (substrates) having uneven surfaces. Although not shown in the results above, in the removal process, the base layer could be peeled off from the protective layer attached to the bare silicon wafer without the protective layer itself. Furthermore, the multiple 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 above-described embodiment, it is possible to efficiently manufacture a semiconductor device or the like that includes a semiconductor chip with almost no foreign matter adhering thereto. [Industrial Applicability]

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

[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: Base layer, 22: Adhesive fixing layer, W: semiconductor wafer, X: semiconductor chip.

Claims

1. a protective layer attached to the surface of the substrate to be protected; the protective layer contains a water-soluble compound, the protective layer has a storage modulus of 50,000 Pa or less at 70°C; A protective sheet, wherein the adhesive strength of the protective layer to a silicon wafer is 0.5 N / 10 mm or more.

2. the protective layer contains a first water-soluble compound and a second water-soluble compound as the water-soluble compounds, the first water-soluble compound is a compound having a polyoxyethylene structure in its molecule, The protection sheet according to claim 1 , wherein the second water-soluble compound is a water-soluble polyester resin having a weight average molecular weight of 2,000 or more.

3. A method for manufacturing an electronic component device, comprising a temporary protection step of protecting a surface of a substrate to be protected with a protective sheet and then removing the protective sheet, the protective sheet comprises a protective layer containing a water-soluble polymer compound and a base layer overlying one side of the protective layer; the adhesive strength of the protective layer to the silicon wafer is 0.5 N / 10 mm or more; the protective layer has a storage modulus of 50,000 Pa or less at 70°C; 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 method for manufacturing an electronic component device, wherein the second step includes a step of peeling the base material layer from the protective layer, and a step of dissolving at least a portion of the protective layer with a liquid containing water to remove the protective layer.

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