protective sheet

Abstract

To provide a protective sheet having a protective layer that is prevented from breaking when it comes into contact with a convex portion of an adherend and that is removable by a liquid including water.SOLUTION: A protective sheet includes a protective layer to be attached to the surface to be protected of an adherend, and a support layer overlapping one side of the protective layer and supporting the protective layer, and the protective layer contains a water-soluble compound, and the following relational expression (1) is satisfied when the thickness of the protective layer is a [μm] and the breaking elongation of the protective layer at 85°C is b [%]. a×b≥120 (1).SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a protective sheet having a protective layer that is attached to, for example, the surface of an adherend 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 support 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 attaching a protective layer of the protective sheet to a surface of an adherend to be protected, a step of processing the adherend, and a step of removing the protective layer from the surface of the adherend to be protected. For example, in this way, the protective sheet is attached to the surface of the adherend to be protected, and then removed from the surface of the adherend to be protected 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 protective layer containing a solid hydrophilic polymer and a liquid compound having a hydrophilic group in the molecule, and a support layer is known (for example, Patent Document 1). The protective sheet described in Patent Document 1 has, for example, a support layer that is a release liner, and can be used by pressing the protective layer against the surface of the adherend to be protected via the support layer, and then peeling and removing the release liner. Furthermore, after the adherend, i.e., a semiconductor wafer, is subjected to processing to be diced, the protective layer can be removed and used. Furthermore, the protective sheet described in Patent Document 1 has a support layer that is, for example, a backgrinding tape, and can be used by pressing the protective layer against one side (the surface to be protected) of the adherend semiconductor wafer via the support layer. Furthermore, after the adherend semiconductor wafer is subjected to a backgrinding process to reduce its thickness, the protective layer and support layer can be removed and the sheet can be used.

[0005] According to the protective sheet described in Patent Document 1, the protective layer can protect the surface to be protected when the adherend is processed, and furthermore, the protective layer can be removed with water after the processing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2024-010412 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the protective sheet described in Patent Document 1 is configured to protect the flat circuit surface of a semiconductor wafer, and when it is attached to a surface to be protected that has convex portions formed by bumps or the like, when a part of the protective layer abuts on the convex portion, the protective layer may not necessarily deform sufficiently in accordance with the shape of the convex portion, and part of the protective layer may tear near the convex portion. To prevent such problems, there is a demand for a protective sheet in which the protective layer is prevented from tearing when it comes into contact with a protrusion such as a bump on an adherend, and in which the protective layer can be removed by a liquid containing water.

[0008] However, it cannot be said that sufficient research has been conducted on a protective sheet in which tearing of the protective layer when it comes into contact with a protrusion on an adherend is suppressed and the protective layer is removable by a liquid containing water.

[0009] Therefore, an object of the present invention is to provide a protective sheet having a protective layer that is prevented from tearing when it comes into contact with a convex portion of an adherend, and that is removable by a liquid including water. [Means for solving the problem]

[0010] In order to solve the above problems, the protective sheet of the present invention comprises: The adhesive tape comprises a protective layer that is attached to a surface to be protected of an adherend, and a support layer that overlaps one surface of the protective layer and supports the protective layer, the protective layer contains a water-soluble compound, When the thickness of the protective layer is a [μm] and the breaking elongation of the protective layer at 85° C. is b [%], the following relational expression (1) is satisfied. a×b≧120 Formula (1) [Effects of the Invention]

[0011] The protective sheet of the present invention can provide a protective layer that is inhibited from tearing when it comes into contact with a protrusion on an adherend, and that can be removed by a liquid containing water. [Brief explanation of the drawings]

[0012] [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 2] FIG. 1 is a schematic cross-sectional view showing an example of a semiconductor wafer as an adherend. [Figure 3A] 10 is a schematic cross-sectional view showing the state of the semiconductor wafer after the surface to be protected has been protected by an example of a protective sheet. FIG. [Figure 3B] 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 3C] FIG. 10 is a schematic cross-sectional view showing the state after a bonding step has been performed using an example of a protective sheet. [Figure 3D] FIG. 10 is a schematic cross-sectional view illustrating a state in which a peeling step of the removal process is performed using an example of a protective sheet. [Figure 3E] 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 3F] 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 3G] 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 3H] 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 removal process. [Figure 3I]10A and 10B are schematic cross-sectional views illustrating a modified example of how the protective layer of the protective sheet is removed by the dissolving step in the removal step. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, one embodiment of a protective sheet according to the present invention will be described in order with reference to the drawings. Note that the drawings are schematic diagrams and do not necessarily have the same aspect ratio as the actual product.

[0014] As shown in FIGS. 1A and 1B, protective sheet 1 of this embodiment comprises at least protective layer 12 containing a water-soluble compound and support layer 11 overlying one side of protective layer 12. 1A, the support layer 11 may have a release liner 11z as a support layer. The protective sheet 1 of this embodiment may have two release liners 11z superimposed on both sides of the protective layer 12, or may have one release liner 11z superimposed on one side of the protective layer 12. 1B, the support layer 11 may have an adhesive layer 11b disposed on one side of the protective layer 12 and a support layer main body 11a overlapping the adhesive layer 11b. The support layer 11 may further have an intermediate layer 11c disposed between the adhesive layer 11b and the support layer main body 11a.

[0015] The protective sheet 1 of this embodiment is used, for example, by being attached to one surface of an adherend 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.

[0016] The protective sheet 1 of this embodiment may be used, for example, as a backgrinding tape or as a dicing tape.

[0017] Protective sheet 1 is used, for example, to temporarily protect the surface of an adherend to be protected. Examples of the 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 adherend include semiconductor wafers for obtaining semiconductor chips, semiconductor chips obtained by cutting semiconductor wafers into small pieces, linked circuit boards formed by linking multiple circuit boards, and circuit boards. The surfaces to be protected of these substrates usually have irregularities.

[0019] A semiconductor wafer W as the adherend 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. For example, in the semiconductor wafer W, the one surface on which the plurality of electrode portions W2 are arranged is the surface to be protected.

[0020] Each electrode portion W2 has a plurality of bump electrodes, and adjacent bump electrodes are arranged with a relatively small gap between them. In other words, in each electrode portion W2, a plurality of bump electrodes are arranged at a 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. The protruding height of each bump electrode (the height from the surface of the semiconductor wafer body W1 to the tip of the bump electrode) is, for example, 10 μm or more and 200 μm or less. In this type of semiconductor wafer W, the one surface on which the bump electrodes are arranged is the surface to be protected.

[0021] The semiconductor wafer W can be 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.

[0022] 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 the surface to be protected, or both sides may be the surface to be protected. In a TSV type semiconductor chip, electrodes may be formed on both sides, so both sides of the semiconductor chip may be the surface to be protected.

[0023] 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.

[0024] 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.

[0025] 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 consist of 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.

[0026] Protective layer 12 has adhesiveness that allows it to adhere closely to the surface of the adherend to be protected. 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, after protective sheet 1 has been used to temporarily protect a surface to be protected as described above, it is removed with a liquid containing water. The method of using protective sheet 1, in which protective layer 12 of protective sheet 1 is attached to an adherend, will be described in detail later.

[0027] [Protective layer of protective sheet] The protective layer 12 contains a water-soluble compound. The water-soluble compound has a hydrophilic group in the molecule. The protective layer 12 preferably contains a water-soluble polymer compound as the water-soluble compound.

[0028] The protective layer 12 preferably contains 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more of a water-soluble polymer compound, which allows the protective layer 12 to be more easily removed by a liquid containing water.

[0029] 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 a compound that is solid at room temperature (23°C). The second water-soluble compound is a compound that is liquid at room temperature. The first water-soluble compound is preferably a first water-soluble polymer compound, and the second water-soluble compound is preferably a second water-soluble polymer compound.

[0030] Both the first water-soluble compound and the second water-soluble compound have such water solubility that when a thin film (thickness of 50 μm or less) of each water-soluble compound is immersed in water at 40° C., it is completely dissolved.

[0031] When the thickness of the protective layer 12 is a [μm] and the breaking elongation of the protective layer 12 at 85° C. is b [%], the following relational expression (1) is satisfied. a×b≧120 Formula (1) Since the relationship of formula (1) is satisfied, the protective layer 12 can deform in accordance with the unevenness of the surface to be protected, and is therefore less likely to break when it comes into contact with a protrusion.

[0032] The value of a×b in the above formula (1) is preferably 120 or more, more preferably 200 or more, even more preferably 300 or more, still more preferably 400 or more, particularly preferably 450 or more, even more particularly preferably 1500 or more, and most preferably 2000 or more. As the value of a×b increases, tearing of the protective layer 12 when it comes into contact with a protrusion is further suppressed. Furthermore, the value of a×b in the above formula (1) may be 5000 or less, 1500 or less, 1000 or less, 800 or less, or 700 or less.

[0033] The thickness a [μm] of the protective layer 12 is, for example, 1 μm or more and 100 μm or less. Such a thickness is preferably 2 μm or more, and more preferably 3 μm or more. The thickness of the protective layer 12 is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less. When the protective layer 12 is a laminate, the above thickness is the total thickness of the laminate. By being thicker than the protective layer 12, it is possible to further suppress tearing when the protective layer 12 comes into contact with a convex portion of the surface to be protected as described above. On the other hand, by being thinner, the protective layer 12 can be more easily removed by a liquid including water.

[0034] The thickness a [μm] of the protective layer 12 is determined by arithmetically averaging the thickness measurements of at least five randomly selected portions.

[0035] The breaking elongation b [%] of the protective layer 12 at 85°C is, for example, 10% or more and 200% or less. Such breaking elongation is preferably 50% or more, more preferably 75% or more, and even more preferably 90% or more. In addition, such breaking elongation may be 175% or less, 150% or less, or 125% or less. By increasing the breaking elongation at 85°C of the protective layer 12, it is possible to further suppress tearing when the protective layer 12 comes into contact with a convex portion of the surface to be protected, as described above.

[0036] The breaking elongation b [%] of the protective layer 12 at 85°C is measured using the following measurement method and conditions. Specifically, a protective layer formed to have a thickness of 200 μm or more and 400 μm or less is prepared. This protective layer is cut to prepare a rectangular sheet-like measurement sample having a width of 5 mm and a length of 40 mm. Then, measurement is performed under the following conditions to measure the breaking elongation [%] at 85°C. Measurement device: Dynamic viscoelasticity measuring device (for example, manufactured by TA, device name "RSA-G2") Measurement temperature: 85℃ Pulling speed: 0.5 mm / sec Chuck distance: 10mm Measurement mode: Tensile mode Breaking elongation (%) = 100 × [(L-L0) / L0] L0: Length before tension (distance between chucks), L: Length at break

[0037] For example, the breaking elongation b [%] can be increased by increasing the proportion of the second water-soluble polymer compound among the water-soluble polymer compounds contained in the protective layer 12. On the other hand, the breaking elongation b [%] can be decreased by increasing the proportion of the first water-soluble polymer compound among the water-soluble polymer compounds contained in the protective layer 12.

[0038] When the storage modulus of the protective layer at 85° C. is taken as c [Pa], the following relational expression (2) is preferably satisfied: Here, the storage modulus refers to the shear storage modulus. {(a×b) / c}×1,000≧1.1 Equation (2)

[0039] The value of {(a×b) / c}×1,000 in formula (2) is more preferably 2.5 or greater, even more preferably 3.2 or greater, even more preferably 40 or greater, and particularly preferably 100 or greater. By increasing the value of {(a×b) / c}×1,000 in formula (2), the protective layer 12 can more fully deform in accordance with the unevenness of the surface to be protected, even if the surface is uneven. Therefore, tearing when contacting a convex portion is more suppressed. Furthermore, the protective layer 12 can more fully penetrate into concave portions, thereby exhibiting better embedding properties.

[0040] The value of {(a×b) / c}×1,000 in formula (2) is preferably 1,000 or less, more preferably 800 or less, and even more preferably 650 or less, in that this can improve the removability of the protective layer 12.

[0041] The storage modulus c [Pa] of the protective layer 12 at 85°C is, for example, 50,000 Pa or more and 600,000 Pa or less. Such a storage modulus is preferably 90,000 Pa or more, more preferably 95,000 Pa or more, and even more preferably 100,000 Pa or more. When the storage modulus of the protective layer 12 at 85°C is increased, tearing of the protective layer 12 when it comes into contact with protrusions on the surface to be protected is further suppressed. On the other hand, the storage modulus of the protective layer 12 at 85°C is preferably not more than 500,000 Pa, more preferably not more than 300,000 Pa, and even more preferably not more than 200,000 Pa. Such a smaller storage modulus allows the protective layer 12 to more fully penetrate into recesses in the uneven surface to be protected, thereby exhibiting better embedding properties.

[0042] 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, dynamic viscoelasticity measurement is performed under the following measurement conditions, and the measured value of the storage modulus (G') [Pa] at 85°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

[0043] For example, the storage modulus c [Pa] 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 c [Pa] can be decreased by decreasing the molecular weight of the water-soluble polymer compound contained in the protective layer 12.

[0044] 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 adherend when it comes into contact with a liquid containing water.

[0045] As described above, the protective layer 12 contains a water-soluble compound having a hydrophilic group in the molecule. The protective layer 12 preferably contains a first water-soluble compound (particularly, a first water-soluble polymer compound) that is solid at room temperature (23°C) and a second water-soluble compound (particularly, a second water-soluble polymer compound) that is liquid at room temperature (23°C). "Liquid at room temperature" refers to the state in which 20 g of a compound is placed in a 50 mL beaker, tilted 90 degrees at 23°C, and flows (the liquid surface approaches horizontal) after 10 seconds. Water-soluble compounds other than these are solid at room temperature.

[0046] The protective layer 12 preferably contains 50 parts by mass or more of the first water-soluble compound, more preferably more than 50 parts by mass, and even more preferably 55 parts by mass or more, per 100 parts by mass of the total amount of the first water-soluble compound and the second water-soluble compound. A larger mass ratio of the first water-soluble compound to the total amount of the first water-soluble compound and the second water-soluble compound has the advantage that it becomes easier to form the protective layer 12 into a sheet, and the breaking elongation can be improved. On the other hand, the protective layer 12 preferably contains 90 parts by mass or less, and more preferably 85 parts by mass or less, of the first water-soluble compound relative to 100 parts by mass of the total amount of the first water-soluble compound and the second water-soluble compound. By reducing the mass proportion of the first water-soluble compound in the total amount of the first water-soluble compound and the second water-soluble compound, the elastic modulus of the protective layer 12 can be reduced, and embeddability can be improved.

[0047] The protective layer 12 preferably contains 50% by mass or more and 90% by mass or less of the first water-soluble compound. The protective layer 12 also preferably contains 10% by mass or more and 50% by mass or less of the second water-soluble compound. This allows the protective layer 12 to have an appropriate breaking elongation at 85°C.

[0048] The protective layer 12 contains, for example, polyvinyl alcohol as the first water-soluble polymer compound.

[0049] The degree of saponification [mol %] of polyvinyl alcohol is preferably 30 or more, more preferably 35 or more, and even more preferably 40 or more. The degree of saponification [mol %] of polyvinyl alcohol is preferably 98 or less, more preferably 90 or less, and even more preferably 60 or less. When the degree of saponification is within the above range, the polyvinyl alcohol can have sufficient water solubility.

[0050] The degree of saponification of polyvinyl alcohol was determined by proton magnetic resonance spectroscopy ( 1 The degree of saponification of polyvinyl alcohol can be measured by H-NMR measurement. If the protective layer contains additives, the peak derived from the additives may overlap with the peak used to calculate the degree of saponification. In such cases, the measurement sample of the protective layer is subjected to a methanol extraction process or the like to remove the additives, and then the degree of saponification of polyvinyl alcohol is measured. Specifically, the degree of saponification of polyvinyl alcohol can be measured under the following measurement conditions. <Measurement conditions> Analytical equipment: e.g., FT-NMR: Bruker Biospin, AVANCE III-400 Observation frequency: 400MHz (1H) Measurement solvent: deuterated water or deuterated dimethyl sulfoxide (deuterated DMSO) ·Measurement temperature: 80℃ ·Chemical shift standard: External standard TSP-d4 (0.00ppm) (when measuring heavy water) Measurement solvent (2.50 ppm) (when measuring deuterated DMSO)

[0051] The degree of saponification of polyvinyl alcohol is calculated based on the following formula using the peaks derived from the methylene groups of the vinyl alcohol unit (VOH) (heavy water: 2.0 to 1.0 ppm, deuterated DMSO: 1.9 to 1.0 ppm) and the peaks derived from the acetyl groups of the vinyl acetate unit (VAc) (heavy water: around 2.1 ppm, deuterated DMSO: around 2.0 ppm). In the following formula, [VOH(-CH2)-] is the intensity of the peak derived from -CH2- in the vinyl alcohol unit, and [VAc(CH3CO-)] is the intensity of the peak derived from CH3CO- in the vinyl acetate unit.

[0052]

number

[0053] The weight average molecular weight Mw of the polyvinyl alcohol is preferably 1,000 or more, more preferably 2,000 or more, even more preferably 3,000 or more, and particularly preferably 4,000 or more. Such a mass average molecular weight Mw may be 15,000 or less, 10,000 or less, 8,000 or less, or 6,000 or less. When the weight average molecular weight Mw of the polyvinyl alcohol is within the above range, the protective layer 12 containing such polyvinyl alcohol has good shape retention and can be formed with a more uniform thickness.

[0054] The average degree of polymerization of polyvinyl alcohol is preferably 50 or more, more preferably 70 or more, and even more preferably 90 or more. The average degree of polymerization may be 1,000 or less, 800 or less, 600 or less, 400 or less, 200 or less, or 150 or less. When the average degree of polymerization is within the above range, the polyvinyl alcohol can have sufficient water solubility, and the protective layer 12 containing such polyvinyl alcohol can have good moldability.

[0055] The weight average molecular weight Mw and average degree of polymerization of polyvinyl alcohol can be measured by aqueous gel permeation chromatography (aqueous GPC) under the following measurement conditions. <Measurement conditions> ·Analyzer: Agilent, 1260Infinity Columns: TSKgel G6000PWXL (Tosoh Corporation) and TSKgel G3000PWXL (Tosoh Corporation) The above two columns are connected in series Column temperature: 40℃ Eluent: 0.2M aqueous sodium nitrate solution ·Injection volume: 100μL Detector: Differential refractometer (RI) Standard samples: PEG standard sample and PVA standard sample

[0056] Specifically, the mass average molecular weight Mw and the average degree of polymerization of polyvinyl alcohol are measured as follows. (1) The mass-average molecular weights Mw of the sample (PVA) and the PVA standard sample are calculated by GPC measurement using a PEG standard sample. The average degree of polymerization of the PVA standard sample is known. (2) A calibration curve is prepared using the average degree of polymerization of the PVA standard sample and the calculated mass average molecular weight Mw of the PVA standard sample. (3) Using the created calibration curve, the average degree of polymerization of the sample (PVA) to be measured is determined from the mass average molecular weight Mw of the sample (PVA).

[0057] The first water-soluble compound may contain a plurality of types of polyvinyl alcohols having different degrees of saponification, or may contain a plurality of types of polyvinyl alcohols having different average degrees of polymerization.

[0058] The protective layer 12 contains, as the second water-soluble compound, for example, a compound having a polyoxyethylene structure in the molecule or a compound having a polyglycerin structure in the molecule.

[0059] The polyoxyethylene structure of the compound having the polyoxyethylene structure in the molecule acts as a hydrophilic group. When the second water-soluble compound has the polyoxyethylene structure as a hydrophilic group in the molecule, it can become more soluble in a liquid containing water even at room temperature.

[0060] Examples of the second water-soluble compound include polyethylene glycol (PEG) having only a polyoxyethylene structure in the molecule (e.g., molecular weight less than 20,000), and ethylene-propylene copolymer (polyalkylene oxide copolymer) having a polyoxyethylene structure and a polyoxypropylene structure in the molecule (e.g., molecular weight less than 50,000). The ethylene-propylene 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.

[0061] The weight average molecular weight Mw and average degree of polymerization of the second water-soluble compound exemplified above can be measured by aqueous gel permeation chromatography (aqueous GPC). The detailed measurement conditions are as follows. <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, etc.) is calculated by GPC measurement using a PEG standard sample.

[0062] When the second water-soluble 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, and the heat resistance of the protective layer 12 can be further improved.

[0063] The mass-average molecular weight Mw of the polyethylene glycol (PEG) is preferably 1,000 or less. By having a mass-average molecular weight Mw of 1,000 or less, the second 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, 300 or more.

[0064] As the polyethylene glycol (PEG) or ethylene-propylene copolymer, commercially available products can be used.

[0065] The compound having a polyglycerin structure in the molecule as the second water-soluble compound is a dehydration condensate of multiple glycerins. The compound having a polyglycerin structure in the molecule is water-soluble due to the presence of a polyglycerol structure in the molecule. The compound having a polyglycerin structure in the molecule may have a hydrophilic functional group such as a hydroxy group (-OH) or a carboxy group (-COOH) in the molecule, or may have a reactive functional group such as a glycidyl group. The hydrophilic functional group may be in the form of a salt.

[0066] The compound having a polyglycerol structure in the molecule may be a polyglycerol of 4 to 10 glycerol units.

[0067] The compound having a polyglycerol structure in the molecule may be a compound in which some of the -OH groups in the polyglycerol molecule have been substituted with functional groups other than -OH groups. Examples of such functional groups include glycidyl groups. In such compounds, all of the -OH groups may be substituted, or only some of the -OH groups may be substituted.

[0068] The compound having a polyglycerin structure in the molecule may be a commercially available product. For example, the "DENACOL series" manufactured by Nagase ChemteX Corporation may be used as a compound having a polyglycerin structure and a glycidyl group in the molecule.

[0069] The second water-soluble compound may contain either a compound having a polyoxyethylene structure in the molecule or a compound having a polyglycerin structure in the molecule, or may contain both.

[0070] The protective layer 12 preferably contains two types of polyvinyl alcohols with different average degrees of polymerization and a compound having a polyglycerin structure in the molecule, and more preferably contains a polyvinyl alcohol with an average degree of polymerization of 50 to 200 and a polyvinyl alcohol with an average degree of polymerization of 300 to 500, and a compound having a polyglycerin structure in the molecule. This allows the protective layer 12 to fully exhibit all of the following: prevention of tearing when it comes into contact with convex portions of the surface to be protected, good embedding properties, and removability with a liquid including water.

[0071] The protective layer 12 of this embodiment may further contain, in addition to the above-mentioned ingredients, a surfactant, for example.

[0072] The protective layer 12 has adhesive properties that allow it to adhere closely to the surface of the adherend to be protected. Furthermore, when the support layer 11 has a release liner 11z, the protective layer 12 can be pressure-sensitively bonded to the release liner 11z with a relatively weak adhesive force. When the support layer 11 has a support layer main body 11a and an adhesive layer 11b, the support layer 11 may have an intermediate layer 11c disposed between the support layer main body 11a and the adhesive layer 11b. The protective layer 12 has adhesive properties that allow it to adhere closely to the adhesive layer 11b.

[0073] [Support layer of protective sheet] The support layer 11 may be a release liner 11z, or may be a laminate of at least the support layer main body 11a and the adhesive layer 11b.

[0074] The thickness of the support 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 support layer 11 is a laminate, the above thickness is the total thickness of the laminate.

[0075] (Support layer body of support layer) The support layer main body 11a of the support layer 11 is made of, for example, a resin film. The support layer main body 11a may contain one type of resin or multiple types of resin. The support layer main body 11a preferably contains 95% by mass or more of resin, and more preferably 98% by mass or more of resin.

[0076] The resin contained in the support layer main body 11a may be a resin having a polar group. When the support layer main body 11a contains a resin having a polar group, the wettability of the surface of the support layer main body 11a is improved. In other words, the surface free energy of the support layer main body 11a can be increased. It is preferable that the wettability on the surface of the support layer main body 11a is relatively high, since this can improve the adhesion between the support layer main body 11a and the adhesive layer 11b or the protective layer 12.

[0077] 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 main body 11a may be a polyimide resin film, a polyamide-imide resin film, or a polyester resin film.

[0078] The thickness of the support layer body 11a may be, for example, 5 μm or more and 50 μm or less.

[0079] (Adhesive layer of support layer) The adhesive layer 11b may be, for example, a pressure-sensitive type (non-pressure-sensitive curing type) having pressure-sensitive adhesive properties. The adhesive layer 11b may also be a curing type that is cured by irradiation with active energy rays. The adhesive layer 11b includes, for example, at least an acrylic resin.

[0080] The pressure-sensitive non-curing adhesive layer 11b may have a substantially non-reactive structure. This type of adhesive layer 11b may contain, for example, a non-crosslinkable acrylic resin. The non-crosslinkable acrylic resin may have, for example, an alkyl (meth)acrylate structural unit in the molecule.

[0081] The curable adhesive layer 11b may contain, for example, an acrylic resin, an elastomer resin, a silicone resin, or a polyvinyl ether resin, and an ultraviolet curable monomer or oligomer. On the other hand, the curable adhesive layer 11b may contain a base polymer having a polymerizable carbon-carbon double bond at the end of the main chain or in a side chain. Examples of such a base polymer include a polymer in which a polymerizable carbon-carbon double bond is introduced into a resin such as an acrylic resin, a vinyl alkyl ether resin, a silicone resin, a polyester resin, a polyamide resin, a polyurethane resin, or a styrene-diene block copolymer. The curable adhesive layer 11b may further contain a photopolymerization initiator.

[0082] The thickness of the adhesive layer 11b may be, for example, 1 μm or more and 10 μm or less.

[0083] (Middle layer of the support layer) The intermediate layer 11c includes, for example, at least an acrylic resin.

[0084] The thickness of the intermediate layer 11c may be, for example, 50 μm or more and 150 μm or less.

[0085] For example, a commercially available adhesive tape (hardening type) can be used as the support layer 11 having the support layer main body 11a and the adhesive layer 11b (and optionally an intermediate layer 11c). As a commercially available product, a commercially available backgrind tape can be used. When a backgrind tape is used as this type of support layer 11, for example, the sheet or tape described in JP 2020-017758 A or JP 2013-213075 A can be used.

[0086] (Release liner as a support layer) The release liner 11z can be a resin film containing the same material as the support layer main body 11a described above. The release liner 11z is preferably a resin film with a release surface treatment. The release liner 11z is used to protect the protective layer 12 and is peeled off, for example, immediately before the protective layer 12 is bonded to the adherend.

[0087] The protective sheet 1 of this embodiment can be produced by a general method, for example, as follows. First, a water-soluble 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) onto, for example, the release liner 11z, and after application, the solution is heated to a temperature at which the solvent volatilizes, thereby forming the protective layer 12 superimposed on the release liner 11z. In addition, a backgrinding tape with protective layer 12 can also be obtained by laminating protective layer 12 overlapping release liner 11z to the adhesive surface of a commercially available backgrinding tape, and then peeling and removing release liner 11z. Although protective sheet 1 can be produced in this manner, the method for producing a protective sheet is not limited to the above-mentioned example method.

[0088] 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.

[0089] 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.

[0090] Various substrates can be used as adherends to which protective layer 12 of protective sheet 1 of this embodiment can be attached. As described above, examples of the substrate include semiconductor wafers, circuit boards, and linked circuit boards (such as pseudo wafers) formed by connecting multiple circuit boards.

[0091] Next, a method for manufacturing the electronic component device will be described.

[0092] The method for manufacturing the electronic component device includes: A method for manufacturing an electronic component device, comprising a temporary protection step of protecting a surface to be protected of an adherend with a protective sheet and then removing the protective sheet, the protective sheet comprises a protective layer containing a water-soluble compound and a support layer overlying one side of the protective layer; the temporary protection step includes a step of bonding the protective layer of the protective sheet to the surface to be protected (hereinafter also referred to as a bonding step), and a step of removing the protective sheet from the surface to be protected (hereinafter also referred to as a removal step), The removal process includes a process of peeling the support layer from the protective layer (hereinafter also referred to as a peeling process), and a process 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 process).

[0093] The method for manufacturing an electronic component device may, if necessary, include a processing step of processing the adherend between the attaching step and the removing step. The processing step may be, for example, a grinding step 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.

[0094] In the above-described method for manufacturing an electronic component device, at least one surface of, for example, a flat plate-shaped adherend (such as a 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 adherend, or may be both surfaces. Note that a circuit component (described in detail later) may or may not be disposed on the surface to be protected.

[0095] The material of the adherend is not particularly limited. Examples of the material of the adherend include glass, silicon, stainless steel (SUS), plastic, and ceramic. Examples of the adherend include semiconductor wafers, sensor wafers such as CMOS or MEMS, pseudo wafers, and circuit boards.

[0096] In the above-mentioned attachment step, a protective layer 12 may be overlaid on the surface of the adherend (such as a substrate) on which at least one of the circuit wiring, sensor portion, and electrode portion is arranged as a circuit component. For example, the protective layer 12 may be overlaid on one side (the surface to be protected) of the substrate on which the circuit wiring is arranged, or on one side of the substrate on which the sensor portion is arranged, or on one side of the substrate on which the electrode portion is arranged. In the above-mentioned attachment step, it is preferable to overlay the protective layer 12 on at least one side of the adherend so as to cover the circuit wiring, sensor portion, or electrode portion with the protective layer 12. Examples of circuit components include circuit wiring, electrode portions, or elements such as transistors, diodes, and sensor portions (such as light-receiving sensors or vibration sensors).

[0097] The following detailed description will be given taking as an example the case of manufacturing a semiconductor device (semiconductor integrated circuit) as an electronic component device. In the following example, protective sheet 1 has a structure as shown in Fig. 1B, and the adherend to which protective layer 12 of protective sheet 1 is attached is a semiconductor wafer, and the surface to be protected has irregularities formed by bumps or the like.

[0098] 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.

[0099] In a pre-process, a circuit surface is formed on one side of a bare wafer to produce a semiconductor wafer W as an adherend. 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 components such as bumps are arranged has irregularities. In this embodiment, a semiconductor wafer W whose irregular side is the surface to be protected is used as the adherend. This semiconductor wafer W is further processed in a post-process.

[0100] In the subsequent process, at least a temporary protection process is carried out, for example, a bonding process in which the protective layer 12 of the protective sheet 1 is bonded to the surface to be protected of the semiconductor wafer W as the adherend, and a removal process in which the protective layer 12 bonded to the surface to be protected is removed. The removal process includes a peeling process in which the support layer 11 is peeled off from the protective layer 12 bonded to the surface of the semiconductor wafer W to be protected, 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 surface of the semiconductor wafer W to be protected. If necessary, between the peeling step and the dissolving step, a blade dicing process subsequent to the laser grouping process in the laser ablation process, or a plasma dicing process of the semiconductor wafer W may be performed. 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.

[0101] 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 to the surface to be protected 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.

[0102] In the above-described method for manufacturing a semiconductor device (electronic component device), a semiconductor device is manufactured using at least the protective layer 12 of the protective sheet 1 and a dicing tape 20 (see FIG. 3C) as follows. The dicing tape 20 has a base layer 21 and an 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.

[0103] 3A, for example, protective layer 12 of protective sheet 1 is superimposed on the surface to be protected of semiconductor wafer W. In the superimposing step, protective layer 12 is superimposed on the surface to be protected by, for example, pressing protective layer 12 directly against the surface to be protected and attaching it thereto. By overlaying the protective layer 12 on the surface to be protected of the semiconductor wafer W, the surface to be protected 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 surface to be protected of the semiconductor wafer W covered with the protective layer 12.

[0104] In the bonding process, the protective layer 12 of the protective sheet 1 is bonded to the surface to be protected of the semiconductor wafer W, which has protrusions such as bumps. At this time, a portion of the protective layer 12 comes into contact with the protrusions, making it prone to tearing. However, because the protective layer 12 has physical properties that satisfy the above-mentioned formula (1), tearing of the protective layer 12 is suppressed.

[0105] The grinding process is carried out as necessary. For example, with the semiconductor wafer W, protective layer 12, and support 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. 3B, grinding (back grinding) is performed using a grinding pad K until the semiconductor wafer W reaches a predetermined thickness. The thickness of the semiconductor wafer W is reduced to the predetermined thickness by the grinding process.

[0106] In the mounting step, as shown in FIG. 3C, a dicing ring R is attached to the adhesive fixing layer 22 of the dicing tape 20, and the semiconductor wafer W is attached and fixed 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 of the semiconductor wafer W to be protected.

[0107] In the peeling step of the removal process, the support 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. 3D, for example. In the peeling step, the support layer 11 may be irradiated with active energy rays such as ultraviolet rays before peeling off the support layer 11. In this case, the support layer 11 is provided with the adhesive layer 11b containing a photopolymerization initiator or the like as described above.

[0108] After the peeling step, if necessary, a dicing step is carried out 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 blade dicing.

[0109] In the dicing step, for example, as shown in FIG. 3E or FIG. 3F, only the protective layer 12 or both the protective layer 12 and the semiconductor wafer W are diced. In the dicing process, for example, after the above-described laser grouping process, the semiconductor wafer W is diced using a blade. In the laser grouping process, the surface to be protected is protected by a protective layer 12, and laser light L is irradiated onto the surface to be protected, as shown in FIG. 3E. For example, when an insulating film called a low-k film, which has a lower dielectric constant than SiO2, is present on the surface to be protected, the laser grouping process can be performed. The wiring layer including the low-k film is removed using the laser light, and two narrow grooves (grooves) are formed at an interval within the dicing street. Then, the semiconductor wafer W can be diced using a blade. 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.

[0110] In the dicing step, the semiconductor wafer W may be diced by laser dicing or plasma dicing. In the laser dicing process, the semiconductor wafer W can be diced into small pieces by irradiating the semiconductor wafer W with a laser. In the plasma dicing process, for example, plasma is irradiated onto the protective layer 12 on the semiconductor wafer W to etch the semiconductor wafer W, thereby dividing the semiconductor wafer W into small pieces. The plasma dicing process is performed in accordance with a conventional method using, for example, a plasma generator.

[0111] 3F, 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 dicing into semiconductor chips X (dies). The weak portion (see cleavage line D shown in FIG. 2) 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.

[0112] Details of the above-mentioned expanding operation are as follows. For example, as shown in FIG. 3F, a dicing ring R is attached to the adhesive fixing layer 22 of the dicing tape 20, and then the dicing ring R is fixed to a holder H of an expanding device. For example, as shown in FIG. 3G, 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.

[0113] In the dissolution step of the removal process, as shown in, for example, Figure 3H or Figure 3I, 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] According to the above-described method for manufacturing a semiconductor device, the protective layer 12 is overlaid on the surface of the semiconductor wafer W on which the circuit components are formed (the surface to be protected), so that the surface to be protected can be protected until the protective layer 12 is removed. Even if foreign matter adheres to the surface to be protected 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 surface to be protected are removed. Therefore, it is possible to prevent foreign matter from adhering to the surface to be protected of the semiconductor chip X to be manufactured. Specifically, it is possible to prevent foreign matter from adhering to protrusions on which bumps or the like are formed.

[0119] 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.

[0120] 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.

[0121] The matters disclosed by this specification include the following. (Section 1) The adhesive tape comprises a protective layer that is attached to a surface to be protected of an adherend, and a support layer that overlaps one surface of the protective layer and supports the protective layer, the protective layer contains a water-soluble compound, A protective sheet in which the following relational expression (1) is satisfied when the thickness of the protective layer is a [μm] and the breaking elongation of the protective layer at 85°C is b [%]: a×b≧120 Formula (1) (Section 2) The protective sheet according to item 1 above, wherein the storage modulus of the protective layer at 85° C. is c [Pa], and the following relational expression (2) is satisfied: {(a×b) / c}×1,000≧1.1 Equation (2) (Section 3) The protective sheet described in (Item 1) or (Item 2) above, wherein the protective layer contains, as the water-soluble compounds, a first water-soluble compound that is solid at room temperature and a second water-soluble compound that is liquid at room temperature. [Example]

[0122] 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.

[0123] Each protective sheet (protective layer) of the Examples and Comparative Examples was prepared as follows.

[0124] <Raw materials for forming the protective layer> (first water-soluble compound) Polyvinyl alcohol (PVA) is solid at room temperature Product name: "JMR-3M" (manufactured by Nippon Vaccination & Poval Co., Ltd.) Degree of saponification: 65%, Degree of polymerization: 100 Polyvinyl alcohol (PVA) is solid at room temperature Product name: "JMR-10M" (manufactured by Japan Vinyl Acetate & Poval Co., Ltd.) Degree of saponification: 65%, Degree of polymerization: 240 Polyvinyl alcohol (PVA) is solid at room temperature Product name: "JMR-20M" (manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.) Degree of saponification: 65%, Degree of polymerization: 400 Polyvinyl alcohol (PVA) is solid at room temperature Product name: "LM-10HD" (Kuraray Co., Ltd.) Saponification degree: 40% Polyvinyl alcohol (PVA) is solid at room temperature Product name: "LM-20" (Kuraray Co., Ltd.) Saponification degree: 40% Polyvinyl alcohol (PVA) is solid at room temperature Product name: "LM-30" (Kuraray Co., Ltd.) Saponification degree: 48% (Second water-soluble compound) Polyethylene glycol (PEG) is liquid at room temperature Molecular weight: approx. 600, Viscosity: 10 mPa·s Commercially available reagent Polyglycerol polyglycidyl ether Viscous liquid at room temperature Product name: Denacol EX-521 (manufactured by Nagase ChemteX Corporation) Viscosity: 4400mPa·s

[0125] [Examples 1 to 17, Comparative Examples 1 to 3] (Preparation of protective sheet) Protective sheets were prepared according to the compositions shown in Tables 1 to 3. Specifically, an aqueous solution of each polymer was prepared so that the total polymer concentration was 20% by mass using the blending composition shown in each table. The solution was heated to 60°C when preparing the aqueous solution of each polymer. The 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 solution of the polymer 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 (two support layers) were prepared.

[0126] (Protective layer breaking elongation at 85°C) The elongation at break of each protective layer was measured at 85° C. according to the method described above. The results are shown in Tables 1 to 3.

[0127] (shear storage modulus of protective layer at 85°C) The shear storage modulus of each protective layer was measured at 85° C. according to the method described above. The results are shown in Tables 1 to 3.

[0128] [Table 1]

[0129] [Table 2]

[0130] [Table 3]

[0131] <Evaluation of tear resistance when the protective layer comes into contact with a convex portion of the adherend surface [Evaluation 1]> Each protective sheet (each protective layer) was attached to a semiconductor wafer having multiple bump electrodes formed on one side (hereinafter referred to as a semiconductor wafer with bump electrodes) as follows, and the resistance of the protective layer to tearing during this process was evaluated. First, each protective sheet was prepared with a backgrind tape (specifically, an adhesive layer) attached to one side of the protective layer. Next, a semiconductor wafer with bump electrodes was fabricated as follows. Specifically, multiple regions in which multiple bump electrodes were arranged were formed on one surface of an 8-inch semiconductor wafer body. In these regions, the diameter of the bump electrodes (bump diameter) was 25 μm, the spacing between adjacent bump electrodes (bump pitch) was 80 μm (the distance between bumps was 30 μm), and the height from the flat portion of the surface of the semiconductor wafer (the surface of the semiconductor wafer body) to the tip of the bump electrode was 55 μm. Next, the protective layer of each protective sheet was attached to one side of the semiconductor wafer body under conditions of a pressure (laminating pressure) of 0.4 MPa and a roller temperature of 85°C. Then, 1000 mJ / cm from the support layer side of the backgrind tape 2 Then, only the back grinding tape was peeled off. Next, the area around the bump electrode was observed at a magnification of 200 times using a microscope. (Evaluation criteria) Excellent (〇): The protective layer was not broken and covered the bump and its surrounding area. Good (△): The protective layer was slightly torn, but the bump and the area around the bump were covered. Poor (×): The protective layer was torn, exposing the bump and its surrounding area.

[0132] <Evaluation of the resistance to tearing when the protective layer comes into contact with a convex portion of the adherend surface [Evaluation 2]> Except for the following changes, the embeddability was evaluated in the same manner as in Evaluation 1. Evaluation 2 was an evaluation test conducted under conditions more severe than those in Evaluation 1 (conditions under which the protective layer was more likely to break). The diameter of the bump electrode (bump diameter) was 20 μm, the distance between adjacent bump electrodes (bump pitch) was 40 μm (distance between bumps: 20 μm), and the height from the flat portion on the surface of the semiconductor wafer (the surface of the semiconductor wafer body) to the tip of the bump electrode was 40 μm.

[0133] <Evaluation of embeddability> The embeddability of each protective sheet in a semiconductor wafer having a plurality of bump electrodes on one surface (hereinafter referred to as a semiconductor wafer 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, a semiconductor wafer with bump electrodes was fabricated as follows. Specifically, multiple regions in which multiple bump electrodes were arranged were formed on one surface of an 8-inch semiconductor wafer body. In these regions, the diameter of the bump electrodes (bump diameter) was 25 μm, the spacing between adjacent bump electrodes (bump pitch) was 80 μm (the distance between bumps was 30 μm), and the height from the flat portion of the surface of the semiconductor wafer (the surface of the semiconductor wafer body) to the tip of the bump electrode was 55 μm. Next, the protective layer of each protective sheet was attached to one side of the semiconductor wafer body under conditions of a pressure (laminating pressure) of 0.4 MPa and a roller temperature of 85°C. The embeddability was then evaluated according to the following criteria by observing the specimen with a digital microscope at a magnification of 200. The results are shown in Tables 1 to 3. (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 (x): Clear voids are observed around the periphery of each bump electrode. In other words, even the top portion of each bump electrode is not fully embedded in the protective layer.

[0134] <Evaluation of the removability of the protective layer using a liquid containing water> To remove the protective layer, the laminate of the bare silicon wafer and the protective layer was immersed in water at 25°C for 30 seconds. The water used to remove the protective layer was then removed. Furthermore, the surface of the bare silicon wafer was analyzed using a Fourier transform infrared spectrophotometer (FT-IR). This analysis confirmed the presence or absence of residual organic matter. The evaluation criteria were as follows: (Evaluation criteria) Good (○) Almost no residual organic matter is found (800-4000 cm -1 (maximum absorption at 1000kJ / s is less than 0.1) Fairly good (△) Residual organic matter is observed (800-4000 cm -1 The maximum absorption at Poor (×) Residual organic matter is found (800-4000 cm -1 (maximum absorption at 0.2 or greater)

[0135] As can be seen from the above evaluation results, the protective layers of the examples had good tear suppression performance when attached to the surface to be protected having convex portions. Furthermore, a specific portion of the protective layer of the example was able to deform sufficiently when attached to a surface to be protected having a protrusion, and therefore was able to fill the recess. In other words, the embedding ability was good. Moreover, the protective layer of the example was easily removed with a liquid containing water.

[0136] 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]

[0137] 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]

[0138] 1: Protective sheet, 11: Support layer (11z: Release liner), 11a: Support layer main body, 11b: Adhesive layer, 11c: Intermediate layer, 12: protective layer; 12': small piece of protective layer; 20: dicing tape, 21: Base layer, 22: Adhesive fixing layer, W: semiconductor wafer, X: semiconductor chip.

Claims

1. The adhesive tape comprises a protective layer that is attached to a surface to be protected of an adherend, and a support layer that overlaps one surface of the protective layer and supports the protective layer, the protective layer contains a water-soluble polymer compound in an amount of 90% by mass or more, A protective sheet, wherein when the thickness of the protective layer is a [μm] and the breaking elongation of the protective layer at 85° C. is b [%], the following relational expression (1) is satisfied: a×b≧120 Formula (1)

2. 2. The protective sheet according to claim 1, wherein the storage modulus of the protective layer at 85°C is c [Pa], and the following relational expression (2) is satisfied: {(a×b) / c}×1,000≧1.1 Formula (2)

3. The protective sheet according to claim 1 or 2, wherein the protective layer comprises, as the water-soluble polymer compounds, a first water-soluble polymer compound that is solid at room temperature and a second water-soluble polymer compound that is liquid at room temperature.

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