Heat-resistant water-soluble film, semiconductor processing tape, and method for manufacturing semiconductor chip

Abstract

Provided are: a water-soluble film for plasma treatment, the film being formed of a curable resin composition containing a water-soluble polymer A and a monomer B that has a (meth)acrylamide structure and does not have a ring structure containing amide nitrogen, wherein the film has a molecular weight of at most 200 and a content of components other than the monomer B of at most 10 mass%; a semiconductor processing tape comprising said water-soluble film; and a method for manufacturing a semiconductor chip using said semiconductor processing tape, the method comprising performing a grinding step, a water-soluble film curing step, a plasma treatment step, and a water washing step on a semiconductor wafer in which the water-soluble film of the semiconductor processing tape is bonded to a circuit surface without heating.

Description

Heat-resistant water-soluble film, semiconductor processing tape, and method for manufacturing semiconductor chips

[0001] The present invention relates to a heat-resistant water-soluble film, a tape for semiconductor processing, and a method for manufacturing semiconductor chips.

[0002] Various products (including semi-finished products) and their materials are usually required to have heat resistance according to the processing conditions, applications, etc. For example, various products and their materials may be subjected to plasma treatment or laser treatment, which uses plasma (plasma gas) or a laser to perform various processes such as surface modification and etching. One example is plasma treatment, which generates plasma in a specific gas to modify the surface of a semiconductor chip (IC), as a means of imparting functionality to the surface layer of a semiconductor chip. In addition, in the manufacture of semiconductor chips, dicing methods for dividing a semiconductor wafer into individual pieces (chips) include a laser dicing method in which a semiconductor wafer is cut by irradiating it with a laser, and a plasma dicing method in which a semiconductor wafer is cut by spraying plasmatized fluorine gas.

[0003] The blade-cut method, which is commonly used to dice semiconductor wafers, has problems such as the relatively large width of the blade (also called the street or scribe line), which prevents efficient utilization of the semiconductor wafer and is prone to minute chipping in the semiconductor chips. Furthermore, the laser dicing method, which ultimately involves physically splitting the semiconductor wafer to separate it, does not effectively prevent chipping. Therefore, plasma dicing, which has the following advantages, has been adopted in place of blade-cut and laser dicing. This plasma dicing method divides and separates the semiconductor wafer by irradiating it with plasma, thereby effectively preventing chipping. Furthermore, the plasma dicing method can form narrow, yet highly linear, streets, allowing for efficient utilization of the semiconductor wafer and enabling it to accommodate the recent rapid advances in thinning and miniaturization of semiconductor chips.

[0004] However, while plasma processing, not limited to plasma dicing, is generally effective for surface modification and processing, it can also damage the surface of the object being processed as a side effect. This is also true for laser processing. Therefore, in laser processing and plasma processing, a means for efficiently protecting areas that should not be irradiated with laser light and areas that should not be exposed to plasma gas from laser light and plasma gas, such as the installation of a mask member, is adopted. A method for providing a mask member is advantageous in that it allows for easy application of a mask member by laminating a processed film. As a method for manufacturing semiconductor chips using such a film-like mask member by plasma dicing, for example, a method has been proposed in which a mask member containing a layer of a water-soluble material is formed on the surface of a semiconductor wafer, a laser is then irradiated on the mask member to decompose and remove a portion of the mask member, thereby exposing the surface of the semiconductor wafer at that portion, and the semiconductor wafer exposed through that portion of the mask member is then cut by plasma etching to divide the semiconductor wafer into semiconductor chips (see Patent Document 1). Furthermore, Patent Document 2 describes a film-like masking member used in a semiconductor chip manufacturing method that employs a plasma dicing method, which is "a film in which a surface protection tape and a water-soluble film are laminated together via an ultraviolet-curable adhesive layer, the water-soluble film being formed by partial saponification of a water-soluble polymer, and which is insoluble in water at room temperature but soluble in warm water at 60°C to 100°C."

[0005] JP-T-2014-523112 A JP-A-2010-165963

[0006] A masking material must be able to adhere to the target object after it has been formed, and also be easily removable (also referred to as "easy peelability") from the target object after it has completed its function as a masking material to simplify the process. Making the masking material water-soluble is an effective way to enhance its removability. However, the surfaces of target objects, such as semiconductor wafers, are often protected with various coating agents to prevent damage caused by humidity, heat, and other factors during the manufacturing process or during use. These coating agents are hydrophobic to reduce water permeability and are therefore incompatible with water-soluble masking materials. Therefore, while making the masking material water-soluble can ensure adhesion to target objects with hydrophilic surfaces and removability by water washing (referred to as "water-washing removability"), it may not exhibit sufficient adhesion to target objects with hydrophobic surfaces.

[0007] Furthermore, in plasma processing, the object to be processed becomes hot due to the irradiation of plasma gas, so the mask material used in plasma processing is required to have sufficient heat resistance to withstand the plasma processing in order to prevent deformation, flow, etc. Specifically, the mask material is required to be suitable for plasma, i.e., plasma heat resistance, so as to be resistant to deformation and flow due to the heat generated by the irradiation of plasma gas, and to protect the masked portion.

[0008] Furthermore, it is desirable that the mask member used in the plasma dicing method for manufacturing semiconductor chips not only have the above-mentioned plasma heat resistance, but also exhibit a higher level of heat resistance than this plasma heat resistance, i.e., laser process suitability. For example, in a plasma dicing method using a mask member, typically, a laser grooving process (laser processing) is performed to form streets by laser irradiation to remove only the intended cutting area of ​​the mask member, and then a dicing process is performed to irradiate (expose) the semiconductor wafer exposed through the streets (grooves) formed in the mask member with plasma to dice it. Therefore, it is desirable that the mask member used in the plasma dicing method not only have plasma heat resistance, but also exhibit high heat resistance (sometimes referred to as laser heat resistance) that makes it highly resistant to deformation even when exposed to heat generated by laser irradiation. Furthermore, in the actual manufacturing of semiconductor chips, due to specific circumstances such as ensuring flexibility in process design, each process may not be performed in a continuous manner. For example, the laser grooving process and the plasma etching process may not be performed consecutively. While being able to accommodate such circumstances in actual manufacturing, in order to carry out the plasma dicing process as desired, it is desirable for the mask member to also exhibit heat resistance (sometimes referred to as aging heat resistance) that suppresses deformation of the streets over time even after laser irradiation. Thus, it is desirable for the mask member used in the plasma dicing method to exhibit laser grooving heat resistance, which is a combination of laser heat resistance and aging heat resistance, as suitability for the laser process.

[0009] However, when a mask member is formed from a highly heat-resistant material, there is generally a trade-off problem in that adhesion to the object to be treated, particularly an object on whose surface the mask member is placed that is hydrophobic, and furthermore removability by washing with water are reduced.

[0010] An object of the present invention is to provide a water-soluble film suitable for use as a masking member, which exhibits high heat resistance while maintaining sufficient adhesion to hydrophobic surfaces and excellent removability through water washing. Specifically, an object of the present invention is to provide a water-soluble film suitable for use as a masking member, which exhibits high heat resistance while maintaining sufficient adhesion to hydrophobic surfaces and excellent removability through water washing. In a preferred embodiment of the present invention, an object of the present invention is to provide a water-soluble film suitable for use as a masking member, which exhibits high heat resistance to plasma and laser grooving while maintaining sufficient adhesion to hydrophobic surfaces and excellent removability through water washing. Another object of the present invention is to provide a semiconductor processing tape having a water-soluble film exhibiting the above-mentioned excellent properties, and a method for manufacturing semiconductor chips using this semiconductor processing tape.

[0011]

[0006] In view of the above problems, the present inventors have conducted extensive research and have found that, by forming a water-soluble film from a curable resin composition containing a water-soluble polymer A and a monomer B having a (meth)acrylamide structure and not having a ring structure containing amide nitrogen, and by controlling the content of components other than the monomer B to 10 mass% or less and having a molecular weight of 200 or less, the film exhibits excellent water-washing removability due to its water solubility and sufficient adhesion to both hydrophobic and hydrophilic surfaces, while also exhibiting high heat resistance capable of withstanding plasma treatment. Furthermore, the present inventors have found that a preferred embodiment of the water-soluble film having the above composition exhibits laser grooving heat resistance that is higher than the plasma heat resistance, while maintaining excellent water-washing removability and sufficient adhesion. The inventors have also found that by forming a semiconductor processing tape by laminating this water-soluble film as a masking material for plasma dicing onto a surface protection tape that protects the circuit surface of a semiconductor wafer during the backgrinding process, the tape can be easily removed by rinsing with water while maintaining adhesion to a wide range of semiconductor wafers and heat resistance sufficient to withstand plasma gas exposure, and in a more preferred embodiment, heat resistance to laser grooving. The inventors have also found that by using this semiconductor processing tape in a semiconductor chip manufacturing method that includes a backgrinding process, a plasma dicing process, a water rinsing process, and preferably a laser grooving process, semiconductor chips can be easily manufactured. Based on these findings, the inventors have further studied and completed the present invention.

[0012] The above-mentioned problems of the present invention are solved by the following means. <1> A heat-resistant water-soluble film formed from a curable resin composition containing a water-soluble polymer A and a monomer B having a (meth)acrylamide structure and not having a ring structure containing amide nitrogen, the film having a molecular weight of 200 or less and a content of components other than the monomer B of 10 mass % or less. <2> The water-soluble film according to <1>, which when cured, has a gel fraction of 10% or less after immersion in water at 30°C for 10 minutes. <3> The water-soluble film according to <1> or <2>, wherein the monomer B is represented by the following formula (B1) or (B2): In formula (B1), R １represents a hydrogen atom or an alkyl group, and R ２ and R ３ represents an alkyl group or an aryl group. ２ and R ３ do not bond to each other to form a ring structure containing N. In formula (B2), R １ represents a hydrogen atom or an alkyl group, and R ４ represents an alkylene group having 1 to 6 carbon atoms, and R ５ and R ６ represents an alkyl group or an aryl group. ５ and R ６ do not bond with each other to form a ring structure containing N. <4> The water-soluble film according to any one of <1> to <3>, wherein the content of the monomer B per 100 parts by mass of the water-soluble polymer A is 100 to 300 parts by mass. <5> The water-soluble film according to any one of <1> to <4>, for use in plasma treatment and / or laser treatment. <6> A semiconductor processing tape, comprising the water-soluble film according to any one of <1> to <5> above and a surface protection tape for protecting the circuit surface of a semiconductor wafer laminated together. <7> A method for manufacturing semiconductor chips, comprising: a step (a) of grinding the back surface of the semiconductor wafer in which the water-soluble film of the semiconductor processing tape described in <6> above has been laminated to the circuit surface of the semiconductor wafer without heating; a step (FC) of irradiating the water-soluble film of the semiconductor processing tape from the surface protection tape side with radiation to harden the water-soluble film; a step (b) of supporting and fixing the semiconductor wafer to a dicing tape via a ring frame; a step (c) of peeling the surface protection tape of the semiconductor processing tape from the hardened water-soluble film to expose the water-soluble film; a step (d) of irradiating the hardened water-soluble film with a laser along regions to be cut of the semiconductor wafer to form grooves; a step (e) of plasma-treating the semiconductor wafer from the water-soluble film side cut in step (d) to individualize the semiconductor wafer; and a step (f) of washing the cut water-soluble film with water to dissolve and remove it.

[0013] The present invention provides a water-soluble film suitable for use as a masking member, which exhibits high heat resistance while maintaining sufficient adhesion to hydrophobic surfaces and excellent removability through water washing. Specifically, the present invention provides a water-soluble film suitable for use as a masking member, which exhibits high heat resistance to plasma while maintaining sufficient adhesion to hydrophobic surfaces and excellent removability through water washing. In a preferred embodiment of the present invention, the present invention provides a water-soluble film suitable for use as a masking member, which exhibits high heat resistance to plasma and laser grooving while maintaining sufficient adhesion to hydrophobic surfaces and excellent removability through water washing. The present invention also provides a semiconductor processing tape having the water-soluble film of the present invention, and a method for manufacturing semiconductor chips using the semiconductor processing tape. The above and other features and advantages of the present invention will become more apparent from the following description, taken in conjunction with the accompanying drawings.

[0014] Fig. 1 is a schematic longitudinal sectional view showing a preferred embodiment of the semiconductor processing tape of the present invention. Fig. 2 is a schematic longitudinal sectional view explaining steps (a) and (FC) in the semiconductor chip manufacturing method of the present invention. Fig. 3 is a schematic longitudinal sectional view explaining steps (b) to (d) in the semiconductor chip manufacturing method of the present invention. Fig. 4 is a schematic longitudinal sectional view explaining steps (e) and (f) and also the pick-up step (g) in the semiconductor chip manufacturing method of the present invention.

[0015] In the present invention, when describing the content, physical properties, etc. of a component by indicating a numerical range, and when the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be appropriately combined to form a specific numerical range. On the other hand, when describing multiple numerical ranges represented using "to", the upper and lower limits forming the numerical range are not limited to the upper and lower limits of the specific combination described before and after "to" as a specific numerical range, but can be a numerical range obtained by appropriately combining the upper and lower limits of each numerical range. Note that in the present invention, a numerical range represented using "to" means a range that includes the numerical values ​​described before and after "to" as the upper and lower limits. In the present invention, (meth)acrylic means one or both of acrylic and methacrylic. The same applies to (meth)acrylate.

[0016] In the present invention, unless otherwise specified, the term "water-soluble film" includes an "uncured water-soluble film" (hereinafter also referred to as a "water-soluble uncured film") containing a monomer B having a (meth)acrylamide structure, as described below, and a "cured water-soluble film" (hereinafter also referred to as a "water-soluble cured film") containing a cured product of monomer B (a polymer of monomer B) as described below, which has been irradiated with radiation. Furthermore, the term "resin composition" that forms the water-soluble film includes a "curable resin composition" containing a monomer B having a (meth)acrylamide structure, as described below, and a "cured resin composition" containing a cured product of monomer B (a polymer of monomer B) as described below, which has been irradiated with radiation. Furthermore, in the present invention, the term "semiconductor processing tape" includes a semiconductor processing tape having a water-soluble uncured film as the water-soluble film (uncured tape for semiconductor processing) and a semiconductor processing tape having a water-soluble cured film (cured tape for semiconductor processing), as described below, unless otherwise specified. Here, the terms "uncured film," "curable resin composition," and "uncured tape" all have radiation curability and refer to a state in which the majority of the monomer B contained therein is uncured, including embodiments in which only a portion (e.g., 70% by mass or less) of the monomer B is cured. Similarly, the terms "cured film," "cured resin composition," and "cured tape" refer to a state in which the majority of the monomer B contained therein is cured, including embodiments in which only a portion (e.g., 70% by mass or less) of the monomer B is uncured. In the present invention, "curable" may include curability due to crosslinking, including a polymer of monomer B, but typically refers to curability due to the polymerization reactivity of monomer B, i.e., "polymerizable." Similarly, "cured" and "cured product" typically refer to "polymerization" and "polymerized product," respectively. In the present invention, "radiation" refers to light rays such as ultraviolet rays or ionizing radiation such as an electron beam, preferably ultraviolet rays.

[0017] [Water-soluble film] The heat-resistant water-soluble film of the present invention (hereinafter sometimes referred to as the film of the present invention) is formed from a curable resin composition described below, and the content of components other than the monomer B described below, which have a molecular weight of 200 or less, in the water-soluble film is 10 mass % or less. This water-soluble film is usually a self-supporting film, although it depends on the film thickness. In the present invention, a self-supporting film refers to a film that can maintain its form as a film even without the presence of other supports, for example, a film that can maintain its film shape.

[0018] The film thickness of the film of the present invention is appropriately set depending on the application, etc., and can be 1 to 800 μm, and is usually 100 to 800 μm. When the film of the present invention is used as a masking member for a semiconductor processing tape, the film thickness is appropriately determined taking into consideration the removability by water washing, the conditions of step (f) described below, and the suppression of the occurrence of edge elution (seepage) in step (a) described below. For example, the film thickness can be 1 to 100 μm, and from the viewpoint of excellent suppression of seepage while maintaining removability by water washing, it is preferably 20 μm or less, more preferably 5 to 20 μm, and even more preferably 5 to 10 μm.

[0019] The film of the present invention is usually in the form of a long strip, but can also be formed into strips, sheets, strings, or other shapes, or into any other suitable shape suitable for the object to be laminated, such as a semiconductor wafer, depending on the intended use, etc. The length and width of the film of the present invention are appropriately set, and for example, the length can be 20 m or more, and the width can be 200 to 400 mm.

[0020] As described above, the film of the present invention has a balance of excellent water-washing removability based on water solubility, sufficient adhesion, and high heat resistance. Here, the heat resistance exhibited by the film of the present invention refers to heat resistance against plasma treatment. The heat resistance exhibited by the film of a preferred embodiment of the present invention includes not only heat resistance against plasma treatment but also heat resistance against laser treatment, for example, laser grooving heat resistance (laser heat resistance and heat resistance over time). Taking advantage of these excellent properties, the film of the present invention can be suitably used for various products and materials that undergo plasma treatment and / or laser treatment (laser grooving process).

[0021] The water-soluble film of the present invention, particularly the water-soluble cured film, has heat resistance sufficient to withstand the high-temperature environment of plasma treatment. Taking advantage of this property, it is suitable for use as a surface protection member (mask member for plasma treatment) for an object to be treated (from plasma gas) during plasma treatment. Examples of plasma treatment include treatments using various plasma gases. Examples of plasma gas include fluorine-based gases, oxygen-based gases, and argon-based gases. Examples of plasma treatment include plasma dicing treatment in semiconductor chip manufacturing methods, desmear treatment to burn off fine dust on the chip surface, and atmospheric pressure plasma treatment to increase the reactivity between the chip surface and other components. Among these, plasma dicing treatment in semiconductor chip manufacturing methods is particularly suitable. The plasma heat resistance exhibited by the film of the present invention is, for example, resistance to plasma treatment under conditions of an output of 0.1 to 300 W (preferably 10 W), a temperature of 10 to 100°C, a pressure of 0.00001 to 0.05 MPa (preferably 0.1 MPa), and a treatment time of 0.1 to 60 minutes, and preferably resistance under the conditions of the plasma dicing step described below (plasma heat resistance in Test 4). Plasma resistance means that the film of the present invention is not softened, melted, or the like when irradiated with plasma gas, and is therefore resistant to deformation and maintains its shape.

[0022] In a preferred embodiment of the present invention, the water-soluble film, particularly the water-soluble cured film, has a high degree of heat resistance that can withstand the high-temperature environment of laser treatment. Taking advantage of this property, it is suitable for use as a surface protection member (laser treatment mask member) for the object to be treated (from laser light) during laser treatment. Examples of laser treatment include treatments using various types of laser light. The laser light is not particularly limited, and examples thereof include excimer laser, CO ２ Examples of laser treatment include laser grooving treatment (step) in semiconductor chip manufacturing methods, laser cutting treatment that alters silicon, and laser marking treatment. Among these, laser grooving treatment in semiconductor chip manufacturing methods is particularly preferred. The laser heat resistance exhibited by a preferred embodiment of the film of the present invention is, for example, resistance to laser treatment under conditions of an output of 0.1 to 10 W, a frequency of 0.1 to 100 kHz, and a processing feed rate of 0.1 to 800 mm / sec (preferably 50 mm / sec), preferably resistance under the conditions of the laser grooving step described below (Test 5). These resistances mean that the film in a preferred embodiment of the present invention is resistant to deformation upon laser irradiation without softening, melting, or the like, and maintains its shape. Regarding heat resistance over time, it is preferable that the film maintains its shape at the time of laser treatment for approximately 14 days after laser treatment under the above conditions (Test 6).

[0023] Taking advantage of its high heat resistance, the water-soluble film of the present invention can be suitably used as a masking member for laser grooving (laser processing) and / or plasma dicing (plasma processing) of the semiconductor processing tape described below in a semiconductor chip manufacturing method including a backgrinding step, a laser grooving step and / or a plasma dicing step, and a water washing step. Specifically, when the water-soluble film of the present invention is incorporated as a masking member into a semiconductor processing tape and used in a semiconductor chip manufacturing method including a plasma dicing step, the circuit surface of the semiconductor wafer can be protected from plasma processing (plasma gas and high-temperature conditions) and deformation (softening) and flow of the masking member due to plasma gas irradiation can be suppressed. Thus, when the film of the present invention is used as a semiconductor processing tape, it is resistant to deformation and flow due to the heat generated by plasma gas irradiation in the plasma dicing step. Furthermore, when a water-soluble film according to a preferred embodiment of the present invention is incorporated as a masking member into a semiconductor processing tape and used in a semiconductor chip manufacturing method including a laser grooving step, the circuit surface of the semiconductor wafer can be protected from high-temperature conditions due to laser irradiation and deformation (softening) and flow of the masking member due to laser irradiation can be suppressed. Thus, when the film of a preferred embodiment of the present invention is used as a semiconductor processing tape, it is resistant to deformation due to the heat generated by plasma gas irradiation in the plasma dicing process, and is also resistant to deformation due to the heat generated by laser irradiation in the laser grooving process, and also exhibits heat resistance over time that suppresses deformation over time of the streets formed in the laser grooving process.

[0024] The water-soluble film of the present invention is water-soluble both in the uncured state and in the cured state, and even after laser treatment and / or plasma treatment in the cured state. The water-soluble film may be water-soluble in water at an appropriate temperature, but is preferably water-soluble in unheated water (usually pure water), for example, water below 60°C, preferably water below 40°C. The lower limit of the water temperature is not particularly limited, but is usually 15°C, preferably 20°C. In the present invention, the water-solubility of the water-soluble film is specifically such that, in the water-washing removability tests (Tests 2 and 3) in the examples, the water-soluble film dissolves in water and can be removed without leaving any adhesive residue below the allowable limit. When such a water-soluble film is incorporated into a semiconductor processing tape as a masking member and used in a semiconductor chip manufacturing method, it can be easily removed after functioning as a masking member.

[0025] The water-soluble film of the present invention exhibits sufficient adhesion to hydrophobic and hydrophilic surfaces, both in the uncured and cured states. The adhesion is high enough to pass the adhesion test (Test 1) in the Examples described below. When a water-soluble film exhibiting such adhesion is incorporated into a semiconductor processing tape as a masking member and used in a semiconductor chip manufacturing method including a back-grinding process, the water-soluble uncured film adheres to semiconductor wafers with a wide range of surface characteristics, protecting the circuit surface of the semiconductor wafer during the back-grinding process. Moreover, even after curing (the water-soluble cured film), adhesion to the semiconductor wafer (circuit surface) is maintained, thereby protecting the circuit surface.

[0026] The film of the present invention exhibits high heat resistance while maintaining excellent removability by water washing and sufficient adhesion. Furthermore, the water-soluble film of the present invention is less likely to transfer the materials forming the mask member, such as the curable resin composition described below, and its cured product to various devices during handling, such as during the performance of various processes, thereby preventing contamination of the devices.

[0027] Here, the water-soluble film of the present invention, in its uncured state (water-soluble uncured film), is formed from a curable resin composition containing a water-soluble polymer A described below and a monomer B described below, and contains the water-soluble polymer A and the monomer B. The water-soluble uncured film and the curable resin composition may further contain a component other than the monomer B, a monomer other than the monomer B, a plasticizer, and other components, each having a molecular weight of 200 or less. On the other hand, in its cured state (water-soluble cured film), the film is formed by curing the curable resin composition (consisting of a cured product of the curable resin composition) and contains the water-soluble polymer A described below and a cured product of the monomer B (polymer B) described below. The water-soluble cured film and the cured product of the curable resin composition may further contain a component other than the monomer B, having a molecular weight of 200 or less, a plasticizer, and other components (excluding components that decompose or disappear upon curing, such as a radical initiator).

[0028] (Water-Soluble Polymer A) The water-soluble polymer A contained in the water-soluble film is typically a water-soluble polymer. The water solubility of the water-soluble polymer A is not particularly limited as long as the water-soluble film can exhibit the above-mentioned water solubility. The water-soluble polymer (also referred to as a water-soluble polymer compound) A is not particularly limited, but preferably, water-soluble polymers such as polyvinyl alcohol, polyethylene glycol, polyethylene oxide, polyvinylpyrrolidone, and poly(2-ethyl-2-oxazoline) can be used. Polyvinyl alcohol may be saponified depending on the water solubility required for the water-soluble film. In terms of water solubility, the water-soluble polymer A is typically a non-crosslinked polymer that does not crosslink by itself, and sufficient water solubility is achieved by using a non-crosslinked water-soluble polymer A. The weight-average molecular weight of the water-soluble polymer A is not particularly limited, but is preferably 200,000 or more. This can impart adhesion and removability to the water-soluble film by washing with water. The weight-average molecular weight of the water-soluble polymer A is more preferably 200,000 to 3,000,000, even more preferably 300,000 to 2,000,000, and particularly preferably 300,000 to 1,000,000, in order to achieve a good balance between high levels of adhesion and removability by water washing. The weight-average molecular weight of the water-soluble polymer A is a value measured by the method described in the Examples. When the water-soluble polymer A is specified by its degree of polymerization, it can be, for example, 200 to 10,000, although this depends on the molecular weight of each constituent component (monomer) that constitutes the water-soluble polymer A.

[0029] (Monomer B) Monomer B contained in the water-soluble uncured film and the curable resin composition is a monomer having a (meth)acrylamide structure and no ring structure containing amide nitrogen, and is radiation polymerizable. Monomer B is a polymerizable compound having a molecular structure in which the oxygen atom of a (meth)acryloyl group and the nitrogen atom of an acyclic amino group are directly bonded. Here, the acyclic amino group refers to an amino group in which the nitrogen atom has two independent substituents. Specifically, it refers to an amino group in which the two substituents on the nitrogen atom bonded to the oxygen atom of the (meth)acryloyl group are bonded to each other to form a ring structure containing the nitrogen atom, and does not include, for example, amino groups formed from cyclic amine compounds such as pyrrolidine, morpholine, and thiomorpholine. The two substituents on the acyclic amino group are not particularly limited and can be any appropriate substituent, but examples thereof include R in the following formula (B1): ２ The two substituents may be the same or different.

[0030] Monomer B is preferably a monomer represented by the following formula (B1) or formula (B2) in that it can balance adhesion, removability by water washing, and heat resistance at high levels, and more preferably a monomer represented by the following formula (B2) in that it can further enhance adhesion while maintaining excellent removability by water washing and heat resistance.

[0031] In formula (B1), R １ represents a hydrogen atom or an alkyl group, and a hydrogen atom is preferred. １ The alkyl group may be any of linear, branched, and cyclic chains, but linear chains are preferred in terms of adhesion, removability by washing with water, and heat resistance. The number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1. ２ and R ３ R each represents an alkyl group or an aryl group, and an alkyl group is preferred. ２ and R ３The alkyl group that can be used as R may be any of linear, branched, and cyclic chains, but linear chains are preferred from the viewpoints of adhesion, removability by washing with water, and heat resistance. The number of carbon atoms in the alkyl group is not particularly limited, and is preferably 1 to 12, more preferably 1 to 8, and even more preferably 1 to 4, from the viewpoint of achieving a high level of adhesion, removability by washing with water, and heat resistance. ２ and R ３ The aryl group that can be used as R is not particularly limited, and examples thereof include aryl groups having 6 to 24 carbon atoms, preferably aryl groups having 6 to 10 carbon atoms, and more preferably aryl groups having 6 carbon atoms. ２ and R ３ R is preferably an alkyl group, since it can achieve a balance of high levels of adhesion, removability by water washing, and heat resistance. ２ and R ３ may be the same or different, provided that R ２ and R ３ do not bond to each other to form a ring structure containing N in the formula.

[0032] In formula (B2), R １ represents a hydrogen atom or an alkyl group, and R in formula (B1) １ It is the same as R ４ represents an alkylene group having 1 to 6 carbon atoms. ４ The alkylene group may be any of straight chain, branched chain, and cyclic chain, but is preferably straight chain from the viewpoints of adhesion, removability by washing with water, and heat resistance. The number of carbon atoms in the alkylene group is not particularly limited, and is preferably 1 to 12, more preferably 1 to 8, and even more preferably 2 to 4, from the viewpoint of achieving a high level of adhesion, removability by washing with water, and heat resistance. ５ and R ６ represents an alkyl group or an aryl group, and an alkyl group is preferable. ５ and R ６ The alkyl group and aryl group that can be taken as R in formula (B1) are respectively ２ and R ３ The alkyl and aryl groups are the same as those that can be taken as R ５ and R ６ do not bond to each other to form a ring structure containing N.

[0033] The monomer represented by formula (B1) and the monomer represented by formula (B2) may each have a substituent. Examples of such a substituent include appropriate substituents, such as an alkyl group, an aryl group, a heterocyclic group (for example, a heterocyclic group having 2 to 12 carbon atoms and at least one oxygen atom, sulfur atom, or nitrogen atom, preferably a 5- or 6-membered heterocyclic group. Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups), and an alkoxy group.

[0034] (Cured Product of Monomer B) The water-soluble cured film and the cured product of the curable resin composition contain the cured product of the above-mentioned monomer B. This cured product is a compound (usually a polymer) obtained by polymerizing monomer B, and includes a homopolymer (poly(meth)acrylamide) obtained by homopolymerizing monomer B, and a copolymer obtained by copolymerizing monomer B with a monomer other than monomer B.

[0035] (Monomers Other Than Monomer B) The water-soluble uncured film and curable resin composition of the present invention may contain a monomer (also referred to as "other monomer") other than monomer B, to the extent that water solubility is not impaired. The other monomer may be any monomer that can be polymerized with monomer B, and examples thereof include polymeric compounds having an ethylenically unsaturated group, and specific examples thereof include (meth)acrylic acid compounds, (meth)acrylic acid ester compounds, styrene compounds, and vinyl compounds.

[0036] (Plasticizer) The water-soluble film preferably contains a plasticizer, since this can further enhance adhesion while maintaining excellent water-washing removability and heat resistance. As the plasticizer, those commonly used in polymerizable compositions can be used, but preferred examples include low-molecular-weight compounds having a molecular weight of 800 or less. This low-molecular-weight compound is preferably a low-molecular-weight polymer, more preferably a water-soluble low-molecular-weight polymer. The water solubility of the water-soluble low-molecular-weight polymer is not particularly limited, as long as the water-soluble film can exhibit the above-mentioned water solubility. The low-molecular-weight compound is not particularly limited, but preferably polyvinyl alcohol or polyethylene glycol can be used. From the viewpoint of water solubility, the low-molecular-weight compound is preferably a compound that does not undergo a chemical reaction, such as a crosslinking reaction, with the water-soluble compound A. The molecular weight of the low-molecular-weight compound (weight-average molecular weight or number-average molecular weight in the case of a polymer) is 800 or less. By setting the molecular weight of the low-molecular-weight compound used in combination with the water-soluble polymer A and monomer B or a polymer thereof to 800 or less, adhesion, water-washing removability, and heat resistance can be achieved at high levels in a well-balanced manner. The molecular weight of the low molecular weight compound is preferably 100 to 800, more preferably 200 to 800, even more preferably 200 to 600, and particularly preferably 450 to 600. The weight average molecular weight or number average molecular weight of the low molecular weight compound (polymer) is a value measured in the same manner as the weight average molecular weight of the water-soluble polymer A. When the low molecular weight compound (polymer) is specified by the degree of polymerization, it can be, for example, 5 to 20, although this depends on the molecular weight of each component that makes up the low molecular weight compound.

[0037] (Components with a molecular weight of 200 or less) The water-soluble film may contain a component with a molecular weight of 200 or less other than monomer B (sometimes referred to as a "low molecular weight component" in the present invention). This low molecular weight component is preferably a component that does not fall into either of the above-mentioned plasticizers with a molecular weight of 200 or less or the following other components with a molecular weight of 200 or less. Examples of low molecular weight components include solvents. The water-soluble film of the present invention preferably does not contain a low molecular weight component. In the present invention, "not containing a certain component" means that the content of the certain component is 0.1% by mass or less.

[0038] (Other Components) The water-soluble film may contain a component that does not fall under any of the water-soluble polymer A, monomer B, or a cured product of monomer B, other monomers, and plasticizers. Examples of other components include ultraviolet absorbers, radical initiators, surfactants, labeling materials, and silane coupling agents. Known ultraviolet absorbers and radical initiators can be used without any particular limitations. Examples of ultraviolet absorbers include benzophenone, benzotriazole, and hydroxyphenyltriazine, with benzotriazole and hydroxyphenyltriazine being preferred from the viewpoint of energy absorption efficiency.

[0039] (Content of each component) The content of each component in the water-soluble uncured film will be described below. The content of each component in the water-soluble cured film is basically the same as the content of each component in the water-soluble uncured film, except that the total content of the content of monomer B and the content of other monomers corresponds to the content of the cured product of monomer B and does not contain any components that decompose or disappear upon curing. The content of each component in the curable resin composition is not particularly limited and can be determined appropriately as long as the content of each component in the water-soluble cured film is satisfied when the water-soluble uncured film is formed, but is preferably the same as the content of each component in the water-soluble cured film. The content of each component in the curable resin composition is basically the same as the content of each component in the curable resin composition, except that the total content of the content of monomer B and the content of other monomers corresponds to the content of the cured product of monomer B and does not contain any components that decompose or disappear upon curing.

[0040] The contents of water-soluble polymer A, monomer B, and other monomers in the water-soluble uncured film are not particularly limited and may be determined appropriately. In terms of adhesion, removability by water washing, and heat resistance, the total content of water-soluble polymer A, monomer B, and other monomers in the water-soluble uncured film is preferably 40 to 100 mass%, more preferably 60 to 95 mass%. The content of monomer B in the water-soluble uncured film is more preferably 20 to 500 mass parts per 100 mass parts of water-soluble polymer A. When the content of monomer B is 500 parts by mass or less, adhesion can be further improved while maintaining excellent removability by water washing and heat resistance. On the other hand, when the content of monomer B is 20 parts by mass or more, adhesion and heat resistance can be further improved while maintaining excellent removability by water washing. The content of the monomer B is more preferably 40 to 400 parts by mass, further preferably 100 to 300 parts by mass, and particularly preferably 150 to 250 parts by mass, relative to 100 parts by mass of the water-soluble polymer A, in order to further improve the heat resistance and thereby to exhibit heat resistance against laser grooving, and as a result, to achieve a good balance of high levels of adhesion, removability by water washing, and heat resistance (a preferred embodiment of the present invention).

[0041] The content of the other monomers in the water-soluble uncured film can be appropriately determined in consideration of the total content, etc., and within a range that does not impair the water solubility of the water-soluble film. For example, in order not to significantly impair the water solubility, it is preferably 50 mass% or less per 100 mass parts of the water-soluble polymer A.

[0042] The total content of water-soluble polymer A, monomer B, other monomers, and plasticizer in the water-soluble uncured film is not particularly limited and may be determined appropriately. The total content is, for example, preferably 60 to 100% by mass, and more preferably 80 to 100% by mass. The content of plasticizer in the water-soluble uncured film is not particularly limited and may be determined appropriately. For example, the content of plasticizer is preferably 0 to 100 parts by mass per 100 parts by mass of water-soluble polymer A. From the viewpoint of achieving a high level of adhesion, removability with water washing, and heat resistance, it is more preferable that the content be 10 to 100 parts by mass, and even more preferable that the content be 20 to 50 parts by mass. The content of plasticizer in the water-soluble uncured film and the curable resin composition, and the content of plasticizer in the water-soluble cured film and the cured resin composition are each set within the above-mentioned ranges, and are preferably the same content.

[0043] The content of low molecular weight components in the water-soluble uncured film is 10% by mass or less. A water-soluble film having a low molecular weight component content of 10% by mass or less forms a self-standing film, which is easy to handle, depending on the film thickness, and can suppress volatilization of low molecular weight components during use. It can also prevent equipment contamination. The content of the low molecular weight components is preferably 3% by mass or less, and more preferably 1% by mass or less, from the viewpoint of effectively suppressing volatilization of low molecular weight components during use, as well as heat resistance and equipment contamination. The content of low molecular weight components in the resin composition is not particularly limited and can be determined as appropriate, and can be, for example, within the range of the content in the water-soluble film.

[0044] The total content of other components in the water-soluble uncured film is not particularly limited and can be determined as appropriate. For example, the content of the UV absorber in the water-soluble film is determined as appropriate depending on the content of monomer B and the absorbance of the water-soluble film, and can be, for example, 0.5 to 35 parts by mass, preferably 0.5 to 15 parts by mass, and more preferably 1 to 13 parts by mass, per 100 parts by mass of water-soluble polymer A. The content of the radical initiator in the water-soluble uncured film and the curable resin composition is determined as appropriate depending on the content of monomer B, the content of other monomers, and the absorbance of the water-soluble cured film, and can be, for example, 0.5 to 25 parts by mass, preferably 0.5 to 15 parts by mass, and more preferably 1 to 13 parts by mass, per 100 parts by mass of water-soluble polymer A.

[0045] The water-soluble cured film preferably has a gel fraction of 10% or less when stirred (at 300 rpm) in 100 g of water at 30°C for 10 minutes. When the gel fraction of the water-soluble cured film is 10% or less, the removability by rinsing with water is improved, and the water-soluble film remaining in a swollen state or adhesive residue can be effectively reduced in step (f) described below. Contamination of the equipment can also be prevented. From the viewpoint of further improving the removability by rinsing with water, the gel fraction of the water-soluble cured film is more preferably 8% or less, and even more preferably 5% or less. The gel fraction of the water-soluble cured film is a value measured using the method and conditions described in the Examples.

[0046] The absorbance of the water-soluble film for electromagnetic waves with a wavelength of 355 nm is not particularly limited, but the absorbance of the water-soluble cured film is preferably 30% or more, and more preferably 50% or more, in terms of excellent groove-forming ability by laser irradiation. The absorbance of the water-soluble film can be appropriately adjusted by the type and content of the ultraviolet absorber. In the present invention, electromagnetic waves refer to electromagnetic waves among the radiation described below, and include, for example, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays. The absorbance is a value measured by the following measurement method. That is, for a water-soluble cured film formed on a PET film (thickness 38 μm), the absorbance is measured in the wavelength range of 300 to 1000 nm using a spectrophotometer U-5100 (manufactured by Yamato Scientific Co., Ltd.) with the PET film as a reference. The absorbance at a wavelength of 355 nm is determined and used as the absorbance of the water-soluble film.

[0047] [Semiconductor Processing Tape] The semiconductor processing tape of the present invention is a laminated tape comprising the water-soluble film of the present invention and a surface protection tape for protecting the circuit surface of a semiconductor wafer. Focusing on the water-soluble film in the semiconductor chip manufacturing method, the semiconductor processing tape of the present invention is suitably used in the following steps (a) (grinding step), (e) (plasma dicing step), and (f) (water washing step), as described below. A preferred embodiment of the semiconductor processing tape of the present invention is suitably used in steps (a) and (d) (laser grooving step), and, as appropriate, steps (e) and (f). Therefore, the semiconductor processing tape of the present invention can also be called a semiconductor wafer processing tape. The uncured semiconductor processing tape has a layered structure in which the water-soluble uncured film and the surface protection tape are laminated and integrated. Because this uncured semiconductor processing tape integrates the surface protection tape and the water-soluble uncured film, when used in the semiconductor chip manufacturing method, the surface protection tape and the water-soluble uncured film can be bonded to the semiconductor wafer at the same time, improving work efficiency. On the other hand, a cured tape for semiconductor processing is a tape having a layered structure in which a water-soluble cured film and a surface protection tape are laminated and integrated. The semiconductor processing tape of the present invention is not particularly limited as long as it has the above-mentioned configuration. For example, a protective layer may be provided on the surface of the water-soluble film and / or the surface protection tape. Furthermore, the film or each layer of the water-soluble film, surface protection tape, etc. may have a single-layer structure or a multi-layer structure of two or more layers.

[0048] The surface protection tape for semiconductor processing of the present invention is difficult to achieve a balance between sufficient adhesion to a wide range of semiconductor wafers, excellent water-rinsing removability, and high heat resistance, and it is also difficult to exhibit laser grooving properties. Therefore, to use the surface protection tape as a semiconductor processing tape to manufacture semiconductor chips, in addition to the surface protection tape, a masking member is required to protect the circuit surface of the semiconductor wafer from plasma treatment, preferably laser grooving treatment. The semiconductor processing tape of the present invention is an integral laminate of the surface protection tape and a water-soluble film exhibiting the above-mentioned excellent properties, allowing the surface protection tape and the water-soluble film to have different functions. As a result, when the semiconductor processing tape of the present invention is used, the application of the surface protection tape and the application of the masking member can be performed simultaneously, allowing for the convenient manufacture of semiconductor chips.

[0049] As shown in FIG. 1, a semiconductor processing tape 3, which is a preferred embodiment of the present invention, has a three-layer structure in which a surface protection tape 4 including a base film 4A and an adhesive layer 4B and a water-soluble film 5 are laminated together in contact with each other via the adhesive layer 4B.

[0050] In the semiconductor processing tape of the present invention, the total thickness and the thickness of each layer are appropriately set depending on the application, etc. For example, the total thickness of the semiconductor processing tape (total thickness of each layer) can be 100 to 800 μm.

[0051] The semiconductor processing tape of the present invention is usually in the form of a long strip, but can also be formed into strips, sheets, strings, or other shapes, as well as any other suitable shape suited to the semiconductor wafer to be laminated, depending on the intended use. The length and width of the semiconductor processing tape are set appropriately; for example, the length can be 20 m or more, and the width can be 200 to 400 mm. The semiconductor processing tape can be produced, for example, by preparing a water-soluble film and a surface protection tape, laminating them together, and adhering them with an adhesive layer.

[0052] By virtue of the above-described constitution, the semiconductor processing tape of the present invention exhibits water-washable removability, adhesion, and heat resistance when in the form of an uncured semiconductor processing tape, and maintains these properties when in the form of a cured semiconductor processing tape.

[0053] In the semiconductor processing tape having the above layer structure, the peel force (180° peel force at 23 ° C.) between the water-soluble film and the surface protection tape (or the adhesive layer if the surface protection tape has an adhesive layer) is set so that adhesion is maintained and no peeling occurs during the step (a) of grinding the back surface of the semiconductor wafer, and the surface protection tape can be easily peeled from the water-soluble cured film before the step (d) of providing grooves in the water-soluble cured film. This peel force is not uniquely determined, but from the viewpoint of the releasability of the surface protection tape from the water-soluble cured film, the upper limit is, for example, preferably 2 N / 25 mm or less, more preferably 1 N / 25 mm or less, and even more preferably 0.5 N / 25 mm or less. On the other hand, from the viewpoint of adhesion during the grinding step, the lower limit is, for example, preferably more than 0.1 N / 25 mm, and more preferably 0.2 N / 25 mm or more. When the adhesive layer of the surface protection tape contains a radiation-curable adhesive, the adhesive layer before curing preferably adheres firmly to the water-soluble uncured film with a peel force that satisfies, for example, the lower limit, while the adhesive layer after curing preferably exhibits a peel force that satisfies, for example, the upper limit. A water-soluble film having the above composition typically exhibits a peel force of 0.1 N / 25 mm from the adhesive layer of the surface protection tape, and this peel force can be appropriately adjusted by changing the composition of the water-soluble film or the adhesive layer. The peel force is a value measured by the following measurement method. Specifically, the semiconductor processing tape of the present invention is cut to a width of 25 mm, and the water-soluble film and the surface protection tape (adhesive layer) are peeled using a Strograph VG1F (trade name, manufactured by Toyo Seiki Seisakusho) at 23°C, a peel angle of 180°, and a peel speed of 300 mm / min, and the maximum peel force is measured. Conditions other than those mentioned above comply with Japanese Industrial Standards (JIS) Z 0237:2009. The maximum peeling force (N / 25 mm) thus obtained is defined as the semiconductor processing tape peeling force (N / 25 mm).

[0054] (Surface Protection Tape) The surface protection tape can be any tape commonly used in semiconductor chip manufacturing methods, without any particular limitations. The surface protection tape has the function of protecting the circuit surface of a semiconductor wafer during the semiconductor chip manufacturing method, particularly the backgrinding process. The surface protection tape used in the present invention has at least a base film and an adhesive layer on the surface of the base film. In the present invention, a preferred surface protection tape 4 has a two-layer structure with an adhesive layer 4B on the surface of a base film 4A, as shown in FIG. 1. In addition to the base film and adhesive layer, a protective layer may be included. The base film and adhesive layer may each have a single-layer structure or a multi-layer structure of two or more layers. The total thickness of the surface protection tape 4 (total thickness of each layer) is not particularly limited and can be, for example, 100 to 800 μm.

[0055] The material for forming the substrate film is not particularly limited, and preferred examples include polyolefin resins such as homopolymers or copolymers of α-olefins, such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, and ionomers, or mixtures thereof; engineering plastics such as polyethylene terephthalate, polycarbonate, and polymethyl methacrylate; and thermoplastic elastomers such as polyurethane, styrene-ethylene-butene-styrene, or pentene copolymers. The substrate film can be produced using a conventional extrusion method. Furthermore, when a film is obtained by laminating various resins, coextrusion, lamination, or the like can be applied. In this case, an adhesive layer may be provided between the resins, as is commonly done in the production of conventional laminate films. The thickness of the substrate film is preferably 30 to 200 μm from the viewpoints of strength, elongation, and radiation transparency.

[0056] The pressure-sensitive adhesive layer may be any layer containing a pressure-sensitive adhesive, and may be formed using, for example, a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition is not particularly limited, and examples include compositions containing typical pressure-sensitive adhesives such as (meth)acrylic, rubber, and silicone. In terms of weather resistance and cost, a (meth)acrylic pressure-sensitive adhesive is preferably used. An example of a (meth)acrylic pressure-sensitive adhesive is a composition containing a copolymer having a (meth)acrylic acid ester as a constituent component (hereinafter referred to as a "(meth)acrylic acid ester copolymer") as an adhesive component. In addition to the (meth)acrylic acid ester copolymer, this composition may also contain a curing agent, etc., as described below.

[0057] Examples of (meth)acrylic acid esters that are components of the (meth)acrylic acid ester copolymer include alkyl acrylates or alkyl methacrylates having a linear or branched alkyl group having 30 or less carbon atoms, preferably 4 to 18 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl, and dodecyl. The (meth)acrylic acid esters may be used alone or in combination of two or more. The content of the (meth)acrylic acid ester component in the components of the (meth)acrylic acid ester copolymer is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95 to 99.9% by mass.

[0058] The (meth)acrylic acid ester copolymer may contain components other than the (meth)acrylic acid ester (also referred to as other components). Examples of other components include carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid, acid anhydride monomers such as maleic anhydride and itaconic anhydride, hydroxyl group-containing monomers such as hydroxyalkyl (meth)acrylates (preferably those in which the alkyl group of the (meth)acrylic acid ester is substituted with a hydroxy group), styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth) Examples of the monomers include sulfonic acid group-containing monomers such as acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid, phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate, (meth)acrylamide, (meth)acrylic acid N-hydroxymethylamide, (meth)acrylic acid alkylaminoalkyl esters (for example, dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, etc.), N-vinylpyrrolidone, acryloylmorpholine, vinyl acetate, styrene, and acrylonitrile. These constituents may be used alone or in combination of two or more.

[0059] In the solid components of the pressure-sensitive adhesive layer, the content of the (meth)acrylic acid ester copolymer (the content converted into the state before reaction with the curing agent or photopolymerizable compound described below) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95 to 99.9% by mass.

[0060] The curing agent that may be contained in the (meth)acrylic adhesive is not particularly limited, and for example, the curing agents described in JP 2007-146104 A can be used. Examples thereof include epoxy compounds having two or more epoxy groups in the molecule, such as 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)toluene, 1,3-bis(N,N-diglycidylaminomethyl)benzene, and N,N,N,N'-tetraglycidyl-m-xylylenediamine, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 1,3-xylylenediisocyanate, and 1,4-xylylenediisocyanate. and diphenylmethane-4,4'-diisocyanate and other isocyanate compounds having two or more isocyanate groups in the molecule, and aziridine compounds having two or more aziridinyl groups in the molecule, such as tetramethylol-tri-β-aziridinyl propionate, trimethylol-tri-β-aziridinyl propionate, trimethylolpropane-tri-β-aziridinyl propionate, and trimethylolpropane-tri-β-(2-methylaziridine)propionate. The content of the curing agent can be adjusted depending on the desired adhesive strength, and is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the (meth)acrylic acid ester copolymer.

[0061] The (meth)acrylic pressure-sensitive adhesive may also be a radiation-curable pressure-sensitive adhesive containing a photopolymerizable compound and a photopolymerization initiator in addition to the pressure-sensitive adhesive component. By containing the pressure-sensitive adhesive component, the photopolymerizable compound, and the photopolymerization initiator, the pressure-sensitive adhesive layer can be cured by irradiation with radiation (preferably ultraviolet light), thereby reducing the adhesive strength of the pressure-sensitive adhesive layer. Examples of such photopolymerizable compounds include low-molecular-weight compounds having at least two photopolymerizable carbon-carbon double bonds in the molecule that can be three-dimensionally reticulated by light irradiation, and oligomers obtained by polymerizing such compounds, as described in JP-A-60-196956 and JP-A-60-223139. The photopolymerizable compound is not particularly limited, and examples thereof include trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, epoxy (meth)acrylate (a (meth)acrylic acid adduct of an epoxy compound), polyester (meth)acrylate (a (meth)acrylic acid adduct of a polyester), and urethane (meth)acrylate (a (meth)acrylic acid adduct of a urethane). The photopolymerization initiator is not particularly limited, and for example, the photopolymerization initiators described in JP-A No. 2007-146104 or JP-A No. 2004-186429 can be used. Specifically, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler's ketone, chlorothioxanthone, benzyl methyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenylpropane, etc. can be used.

[0062] In addition to the combination of the above-mentioned (meth)acrylic acid ester copolymer and a low-molecular-weight compound having at least two radiation-polymerizable carbon-carbon double bonds in the molecule, it is also preferable to use a (meth)acrylic copolymer having a (meth)acrylic acid ester as a constituent component, in which the repeating unit constituting this copolymer has a radiation-polymerizable carbon-carbon double bond (hereinafter referred to as a "radiation-polymerizable (meth)acrylic copolymer"). A radiation-polymerizable (meth)acrylic copolymer is a copolymer having reactive groups in its molecules that can undergo polymerization upon irradiation with radiation, particularly ultraviolet light. Such reactive groups are ethylenically unsaturated groups, i.e., groups having a carbon-carbon double bond (ethylenically unsaturated bond), such as vinyl groups, allyl groups, styryl groups, (meth)acryloyloxy groups, and (meth)acryloylamino groups. The radiation-polymerizable (meth)acrylic copolymer is not particularly limited, and examples thereof include a (meth)acrylic copolymer obtained by reacting a (meth)acrylic copolymer having a functional group a with a compound having a functional group b reactive with the functional group a and a radiation-polymerizable carbon-carbon double bond (hereinafter referred to as a "radiation-polymerizable compound having functional group b"). Examples of the (meth)acrylic copolymer having a carbon-carbon double bond include materials similar to those described in paragraphs

[0036] to

[0055] of JP 2014-192204 A.

[0063] In the radiation-polymerizable compound having the functional group b, examples of the functional group b include a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group. Specific examples of the radiation-polymerizable compound having the functional group b include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, glycol monoacrylates, glycol monomethacrylates, N-methylol acrylamide, N-methylol methacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride, phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and polyisocyanate compounds in which some of the isocyanate groups have been urethanized with a monomer having a hydroxyl group or a carboxyl group and a radiation-polymerizable carbon-carbon double bond. In the reaction between the (meth)acrylic copolymer having the functional group a and the radiation-polymerizable compound having the functional group b, the acid value, hydroxyl value, etc. can be appropriately set by leaving unreacted functional groups.

[0064] The radiation-polymerizable (meth)acrylic copolymer can be obtained by solution polymerization in various solvents. Ketones, esters, alcohols, and aromatic solvents can be used as organic solvents for solution polymerization. Generally, it is preferable to use a solvent that is a good solvent for acrylic polymers and has a boiling point of 60 to 120°C. Examples of solvents that can be used include toluene, ethyl acetate, isopropyl alcohol, benzene, methyl cellosolve, ethyl cellosolve, acetone, and methyl ethyl ketone. Radical generators that can be used as polymerization initiators include azobis-based initiators such as α,α'-azobisisobutylnitrile and organic peroxide-based initiators such as benzoyl peroxide. In this process, catalysts and polymerization inhibitors can be used in combination, as needed, and copolymers with the desired molecular weight can be obtained by adjusting the polymerization temperature and time. The synthesis method is not limited to solution polymerization; other methods such as bulk polymerization and suspension polymerization can also be used.

[0065] In addition, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3 may appropriately contain a release agent, a tackifier, an adhesion adjuster, a surfactant, or other modifiers, etc. Furthermore, it may contain an inorganic compound filler.

[0066] The pressure-sensitive adhesive layer can be formed by applying the pressure-sensitive adhesive composition to a substrate such as a release film, drying it, and then transferring it to the surface of the substrate film.

[0067] There are no particular restrictions on the thickness of the adhesive layer as long as it does not interfere with adhesion to the water-soluble film and does not cause infiltration of dust or grinding water during grinding, but a thickness of 5 to 100 μm is usually appropriate.

[0068] [Method for Manufacturing Semiconductor Chips] Next, the method for manufacturing semiconductor chips of the present invention (hereinafter sometimes simply referred to as the "manufacturing method of the present invention") comprises the following steps, and semiconductor chips can be easily manufactured by subjecting a semiconductor wafer to the treatment of each step. Therefore, the method for manufacturing semiconductor chips of the present invention can also be called a method for processing a semiconductor wafer. The manufacturing method of the present invention is a method in which the following steps (a) to (f) are carried out sequentially in this order, and other steps employed in semiconductor chip manufacturing methods can also be carried out as appropriate before step (a), between each step, or after step (f). In the present invention, step (FC) is carried out before step (b) in consideration of handleability, manufacturing workability, etc., but it can also be carried out after step (b), i.e., after fixing to dicing tape. Step (a): grinding the backside of a semiconductor wafer in which the water-soluble film of the semiconductor processing tape of the present invention has been attached to the circuit side of the semiconductor wafer without heating; Step (FC): irradiating the water-soluble film of the semiconductor processing tape with radiation from the surface protection tape side to harden the water-soluble film; Step (b): supporting and fixing the semiconductor wafer obtained in Step (FC) to a dicing tape via a ring frame; Step (c): peeling the surface protection tape of the semiconductor processing tape from the hardened water-soluble film (water-soluble cured film) to expose the water-soluble cured film; Step (d): irradiating the water-soluble cured film with a laser along the intended cutting region of the semiconductor wafer to cut it and form grooves; Step (e): treating the semiconductor wafer with plasma from the cut water-soluble cured film side to separate the semiconductor wafers; Step (f): washing the cut water-soluble cured film with water to dissolve and remove it.

[0069] The semiconductor wafer used in the manufacturing method of the present invention is a wafer having a circuit surface (also called a pattern surface) on one side on which circuits or the like of semiconductor elements are formed, such as silicon wafers, SiC wafers, GaAs wafers, and GaN wafers. In the present invention, the circuit surface refers to the surface of the semiconductor wafer on which patterns such as circuits of semiconductor elements are formed, and the back surface refers to the surface opposite the circuit surface on which circuits or the like are not formed (non-circuit surface). This circuit surface has lattice-like streets in a plan view. Here, the streets refer to the cutting lines of the semiconductor wafer. In the manufacturing method of the present invention using the semiconductor processing tape of the present invention, the surface characteristics of the semiconductor wafer to which the semiconductor processing tape is bonded are not limited to hydrophilicity and can also be hydrophobic. Treatments for hydrophobizing the surface of the semiconductor wafer are not particularly limited, and include, for example, coating with a hydrophobic coating agent, sputtering, and the like. Examples of hydrophobic coating agents applied to the surface of the semiconductor wafer include benzocyclobutene.

[0070] In the manufacturing method of the present invention, the processes other than the processes related to the semiconductor processing tape of the present invention can be applied without any particular restrictions to the processes used in ordinary semiconductor chip manufacturing methods. The equipment and materials used in the manufacturing method of the present invention can be those conventionally used for processing or treating semiconductor wafers without any particular restrictions, and the operating conditions of the equipment can be set appropriately.

[0071] The manufacturing method of the present invention will be specifically described with reference to the drawings, focusing on the processing related to the semiconductor processing tape of the present invention. In the following description and drawings, the same or corresponding elements are designated by the same reference numerals, and redundant explanations will be omitted. Figures 2 to 4 are schematic vertical cross-sectional views (cross-sectional views cut in the thickness direction along the diameter direction of a semiconductor wafer) showing a preferred embodiment of the manufacturing method of the present invention.

[0072] In the manufacturing method of the present invention, prior to step (a), as shown in FIG. 2(a-1), the semiconductor processing tape 3 and the semiconductor wafer 1 are laminated and bonded together under unheated conditions, so that the water-soluble uncured film 5 of the semiconductor processing tape (uncured tape for semiconductor processing) 3 according to a preferred embodiment of the present invention contacts the circuit surface 1A of the semiconductor wafer 1. In the present invention, "under unheated conditions" refers to, for example, a temperature below 60°C, preferably 40°C or lower. The lower limit temperature is not particularly limited, but is typically 15°C, preferably 20°C. Conventional methods can be used to bond the semiconductor processing tape 3 and the semiconductor wafer 1, without any particular restrictions. However, because the water-soluble uncured film 5 has sufficient adhesion (adhesion) to the semiconductor wafer 1, they can be bonded simply by laminating them together, with further pressure applied if necessary. During bonding, a semiconductor processing tape 3 of the same size or smaller than the semiconductor wafer 1 is used so that it does not protrude beyond the outer periphery of the semiconductor wafer 1 when bonded to the semiconductor wafer 1. This makes it possible to prevent damage such as burning of semiconductor processing tape 3 (water-soluble cured film 5C) that protrudes from semiconductor wafer 1 by plasma in the singulation step (e) described below.

[0073] Next, the back surface 1B of the semiconductor wafer 1 thus obtained, with the water-soluble uncured film 5 of the semiconductor processing tape 3 laminated to the circuit surface 1A as shown in FIG. 2(a-1), is ground (step (a)). As a result, as shown in FIG. 2(a-2), the semiconductor processing tape 3 is laminated to the circuit surface 1A, and the semiconductor wafer 1 is thinned to a predetermined thickness. The method for grinding the back surface 1B of the semiconductor wafer 1 is not particularly limited, and examples include the commonly applied back-grinding (BG) step or etching step, with the BG step being preferred. Conventional methods and conditions can be applied to the method and conditions in step (a).

[0074] In the manufacturing method of the present invention, next, as shown in FIG. 2 (FC), the water-soluble uncured film 5 of the semiconductor processing tape 3 is irradiated with radiation 5U from the surface protection tape 4 side (step (FC)). This hardens the water-soluble uncured film 5 to form a water-soluble cured film 5C, which becomes a cured tape for semiconductor processing. The method and conditions for irradiating radiation can be those of commonly used equipment and conditions, and are set appropriately taking into consideration the composition, physical properties, etc. of the water-soluble uncured film 5. For example, using a known ultraviolet irradiation device, ultraviolet light with an intensity of 10 to 1000 mW / cm is irradiated. ２ The irradiation time can be selected from conditions of 5 to 100 seconds.

[0075] When the pressure-sensitive adhesive layer 4B contains a radiation-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer 4 is also cured together with the water-soluble uncured film 5 in the step (FC).

[0076] 3(b), the semiconductor wafer 1 obtained in step (FC) is then supported and fixed to a dicing tape 11 via a ring frame 12 (step (b)). The ring frame 12 and dicing tape 11 used in step (b), as well as the method of supporting and fixing, may be any commonly used method without any particular limitations. For example, the dicing tape 11 may be a laminated tape of a base film 11A and a pressure-sensitive adhesive layer 11B, and specifically, the tape described in Patent Document 2 may be used.

[0077] 3(c), the surface protection tape 4 (base film 4A and adhesive layer 4B) of the semiconductor processing curable tape 3 is peeled from the water-soluble cured film 5C (step (c)). In this way, the surface protection tape 4 is removed to expose the water-soluble cured film 5C, resulting in a semiconductor wafer 1 having the water-soluble cured film 5C laminated to the circuit surface 1A. The surface protection tape 4 can be peeled with a force equal to or greater than the peel strength between the water-soluble cured film 5C and the surface protection tape 4. If the adhesive layer 4B contains a radiation-curable adhesive, the adhesive layer 4B can be cured by irradiating radiation from the surface protection tape 4 side, thereby making the surface protection tape 4 more easily peelable from the water-soluble cured film 5C. Conventional methods can be used to peel the surface protection tape 4.

[0078] In the manufacturing method of the present invention, as shown in FIG. 3(d-1), a laser is then irradiated along the intended cutting regions (streets, not shown in FIG. 3(d-1)) of the semiconductor wafer 1 obtained in step (c) to cut the water-soluble cured film 5C (step (d)). Then, as shown in FIG. 4(d-2), grooves 8 are formed in the water-soluble cured film 5C, allowing the semiconductor wafer 1 to be irradiated with plasma, as described below, to separate the water-soluble cured film 5C. This exposes the intended cutting regions of the semiconductor wafer 1 at the bottoms of the grooves 8. The width of the formed grooves 8 is preferably equal to or less than the width of the streets. For example, a method for cutting the water-soluble cured film 5C includes a laser grooving method, in which a laser beam 7 output (emitted) from a laser beam irradiator 6 is irradiated onto the water-soluble film 5 while moving the laser beam 7 relatively along the streets, thereby cutting the film 5, as shown in FIG. 3(d-1). For example, the device described in Patent Document 2 can be used as the laser beam irradiator 6. When the water-soluble cured film 5C of the semiconductor processing cured tape 3 is cut by laser irradiation, the individual pieces of the water-soluble cured film 5C do not soften or melt, allowing grooves 8 of a predetermined size and shape to be formed. Furthermore, the water-soluble cured film 5C is resistant to deformation over time, allowing the grooves 8 to maintain the width they had at the time of formation for a long period of time. Groove formation conditions (laser irradiation conditions) for the laser grooving method can be those typically used, but are appropriately set taking into consideration the composition and physical properties of the water-soluble cured film 5C, etc. For example, the conditions for the laser grooving method can be selected from an output of 0.3 to 4.0 W, a frequency of 50 to 100 kHz, and a processing feed rate of 1 to 800 mm / sec.

[0079] Next, as shown in FIG. 4( e), plasma 10A is irradiated onto the exposed portion of the semiconductor wafer 1 from the cut (diced) water-soluble cured film 5C side, thereby performing plasma treatment (step (e)). In this way, the semiconductor wafer 1 is etched and divided into individual chips 2. The method for dividing the semiconductor wafer 1 can be any commonly used plasma dicing method, without any particular restrictions. In the manufacturing method of the present invention, as shown in FIG. 4( e), the process is performed under appropriate conditions using a plasma etching apparatus 10. For example, the apparatus described in Patent Document 2 can be used as the plasma etching apparatus 10. Even when irradiated with plasma gas, the water-soluble cured film 5C of the semiconductor processing cured tape 3 does not soften or melt the divided water-soluble cured film 5C, and can maintain the grooves 8 of the predetermined size and shape. Specific conditions for plasma dicing include SF ６ A fluorine-based gas such as fluorine-containing gas is introduced, and the etching rate can be selected from 0.5 to 10 μm / s. The temperature, pressure, and the like can also be set appropriately depending on the type of plasma gas (generation conditions), etc. For example, the temperature can be set to 20 to 80°C, and the pressure can be set to 0.00001 to 0.05 MPa. The plasma treatment time can be determined appropriately taking into account the output of the apparatus, the etching rate, and the like, and can be set to, for example, 1 to 30 minutes. The output of the plasma etching apparatus can also be set appropriately, and can be set to, for example, 1 to 300 W.

[0080] In the manufacturing method of the present invention, the cut (singulated) water-soluble cured film 5C is then washed with water, preferably unheated water (usually pure water) 9 (step (f)), as shown in FIG. 4(f). Thus, the water-soluble cured film 5C is dissolved and removed to obtain semiconductor chips 2. The method for washing and removing the water-soluble cured film is not particularly limited, as long as it involves contacting the water-soluble cured film with water. For example, a method may be used in which an assembly of singulated semiconductor chips 2 fixed to a ring frame 12 is held on a spinner table, and while rotating the assembly of semiconductor chips 2, cleaning water consisting of water 9 and air is sprayed from a nozzle positioned above the center of the assembly of semiconductor chips 2, and then air is sprayed onto the semiconductor chips 2 from an air nozzle to dry them. Because the water-soluble cured film of a preferred embodiment of the semiconductor processing tape of the present invention exhibits sufficient solubility in unheated water as described above, unheated water can be used as the water used to wash the water-soluble cured film in this step, making this step simple and energy-efficient. The temperature of the washing water is not particularly limited and can be determined as appropriate; for example, it can be less than 60°C, and preferably 40°C or lower. The lower limit of the water temperature is not particularly limited, but can usually be 15°C, and preferably 20°C. The water washing method is not particularly limited, and examples include a method of spraying water onto the semiconductor chip assembly, a method of applying water onto the semiconductor chip assembly, and a method of immersing the semiconductor chip assembly in water. The water washing conditions are determined as appropriate taking into account the water solubility and thickness of the water-soluble cured film, and can be selected from conditions such as a water volume of 10 to 500 mL / min, a water washing time of 1 to 5 minutes, and a drying time of 1 to 5 minutes.

[0081] In the manufacturing method of the present invention, a pick-up step (g) can be performed in which the aggregate of semiconductor chips 2 (singulated semiconductor wafer 1) obtained in step (f) is picked up, as shown in Fig. 4(g) . The pick-up step (g) can be performed using a commonly used method without any particular limitations, and an example of this method is a method in which the semiconductor chips 2 are pushed up together with the dicing tape 11 by pins 15 and then sucked by a collet 16 to pick up the semiconductor chips 2, as shown in Fig. 4(g) .

[0082] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0083] [Preparation of Uncured Tape for Semiconductor Processing] Example 1 (1) Preparation of Surface Protection Tape 100 parts by mass of an acrylic polymer (manufactured by Shin-Nakamura Chemical Co., Ltd.) containing 2-ethylhexyl acrylate as a constituent component was dissolved in ethyl acetate with 1.5 parts by mass of the curing agent, Coronate L (product name, manufactured by Tosoh Corporation), to obtain an ethyl acetate solution of adhesive. This solution was coated onto a release-treated PET film (Cerapeel WZ (product name), thickness 25 μm, manufactured by Toray Industries, Inc.) so that the dry thickness was 30 μm, and then dried by heating. The adhesive layer formed on the PET film was then bonded to a 100 μm-thick polyethylene substrate film (Nipolon Hard 4010 (product name, manufactured by Tosoh Corporation)) extruded to a thickness of 100 μm to prepare a surface protection tape with a PET film.

[0084] Coronate L

[0085] (2) Preparation of Water-Soluble Uncured Film 100 parts by mass of polyvinylpyrrolidone (PVP-K90: trade name) dissolved in 500 mL of water was blended with 25 parts by mass of N-[3-(dimethylamino)propyl]acrylamide (DMAPAA) as monomer B, 1.3 parts by mass of KIP-100F (trade name) as a photoradical initiator, 70 parts by mass of polyethylene glycol (PEG400) as a plasticizer, and 1.9 parts by mass of Tinuvine 477 (trade name) as an ultraviolet absorber to obtain a water-soluble film solution (mask material solution, aqueous solution of curable resin composition). This solution was coated on a release-treated PET film (Cerapeel WZ (trade name), thickness 25 μm, manufactured by Toray Industries, Inc.) so that the thickness after drying was 10 μm, and then heated and dried. In this way, a water-soluble uncured film (water-soluble uncured film with PET film) composed of the curable resin composition was prepared.

[0086] (3) Production of Uncured Tape for Semiconductor Processing After that, the PET film was peeled off from the surface protection tape with PET film obtained in (1) above, and the water-soluble uncured film of the water-soluble uncured film with PET film was bonded to the adhesive layer of the surface protection tape from which the PET film had been peeled off, to obtain an uncured tape for semiconductor processing. This uncured tape for semiconductor processing has a four-layer laminate structure of base film / adhesive layer / water-soluble uncured film / PET film.

[0087] Examples 2 to 12 and Comparative Examples 1 to 8 Uncured tapes for semiconductor processing of Examples 2 to 12 and Comparative Examples 1 to 8 were produced in the same manner as in Example 1, except that in the "Preparation of water-soluble uncured film" of Example 1, the components and contents (composition) forming the water-soluble uncured film were changed to the components and contents shown in the "Water-soluble film" column of Table 1 or Table 2. In Tables 1 and 2, if the "Content (parts by mass)" column for each component is left blank, it means that the component was not contained.

[0088] Comparative Example 9 An attempt was made to produce a water-soluble uncured film in the same manner as in Example 1, except that in the "Preparation of a Water-Soluble Uncured Film" of Example 1, an isopropyl alcohol solvent was added as a low-molecular-weight component in an amount of 20 mass% to the water-soluble uncured film to be produced. However, the film shape could not be maintained. Therefore, the uncured tape for semiconductor processing of Comparative Example 9 could not be produced either.

[0089] The materials used in each example and comparative example are as follows: (Water-soluble polymer A) PVP: polyvinylpyrrolidone, PVP-K90 (trade name), manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., weight average molecular weight measured by the above-mentioned method: 360,000 PVA: polyvinyl alcohol, Poval 60-98 (trade name), saponification degree 98%, manufactured by Kuraray Co., Ltd., weight average molecular weight measured by the above-mentioned method: 400,000 (Monomer B) DMAPAA: N-[3-(dimethylamino)propyl]acrylamide, manufactured by KJ Chemicals Co., Ltd. DEAA: diethylacrylamide, manufactured by KJ Chemicals Co., Ltd.

[0090] (Photoradical initiator) KIP-100F: Trade name, a mixture of Oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and 2-hydroxy-2-methylpropiophenone, manufactured by BASF (Plasticizer) PEG400: Polyethylene glycol, number average molecular weight 400, manufactured by Sanyo Chemical Industries, Ltd. PEG600: Polyethylene glycol, number average molecular weight 600, manufactured by Sanyo Chemical Industries, Ltd. (Other components) Tinuvin 477: Ultraviolet absorber, manufactured by BASF M5700: Trade name, 2-hydroxy-3-phenoxypropyl acrylate, manufactured by Toagosei Co., Ltd. ACMO: Acryloylmorpholine, manufactured by KJ Chemical Co., Ltd. (Solvent) Water: Pure water

[0091] The weight-average molecular weight (Mw) of polyvinylpyrrolidone K90 and the number-average molecular weight of the plasticizer were measured as values ​​(polyethylene glycol / polyethylene oxide (PEG / PEO) converted values) by gel permeation chromatography (GPC) under the following conditions. GPC conditions: Column: TSKgel SuperMultiporePW-M (6.0 mm I.D. × 15 cm) Eluent: 100 mmol / L NaNO ３ Flow rate: 0.6 mL / min Detector: RI Temperature: 25°C Injection volume: 20 μL Sample preparation: A 3 mg / mL solution of the sample was prepared using pure water. The retention volume obtained by GPC measurement was converted to molecular weight using a calibration curve created with PEG / PEO for molecular weight calibration. For PEG / PEO, an Agilent polyethylene glycol / polyethylene oxide standard kit was used.

[0092] [Tests] The uncured tapes for semiconductor processing obtained in the above examples and comparative examples were tested for the following items. The results are summarized in Table 1 or Table 2.

[0093] <Test 1: Adhesion> The adhesion of each uncured semiconductor processing tape prepared in each Example and Comparative Example to a semiconductor silicon wafer (bare wafer) that had not been surface-coated and a silicon wafer (BCB-coated wafer) whose surface had been coated with benzocyclobutene (BCB) to a thickness of 1 μm was evaluated by measuring the peel force (N / 25 mm) using the following test. A water-soluble film solution prepared in the same manner as in the Examples and Comparative Examples was applied to an adhesion-treated PET film and then dried by heating to prepare a test tape of PET film (thickness 38 μm) / water-soluble uncured film (thickness 10 μm). The adhesion treatment was performed by subjecting the surface of the PET film to a corona treatment at a strength of 5A. The obtained test tape was then cut to a width of 25 mm, and the water-soluble uncured film surface of the test tape was then attached to the mirror surface of a silicon wafer that had not been surface-coated and the coated surface of a silicon wafer that had been BCB-coated at a temperature of 23° C., respectively, and the water-soluble uncured film was then cured. The test tape was laminated on a silicon wafer, and a rubber roller with a load of 2 kg was rolled back and forth three times on the surface of the test tape. ２ A metal halide lamp with an intensity of 1000 mJ / cm ２The test was performed by irradiating ultraviolet light of 1000 W at 1000 W. For each wafer, the maximum peel strength between the water-soluble cured film and the wafer was measured immediately after lamination (curing) and after leaving the film in an environment at a temperature of 23°C and a humidity of 50% RH for 1 hour using a Strograph VG1F (trade name, manufactured by Toyo Seiki Seisaku-sho, Ltd.) under conditions of 23°C, a peel angle of 180°, and a peel speed of 300 mm / min. All other conditions conformed to Japanese Industrial Standards (JIS) Z 0237:2009. For each wafer, the maximum peel strength (N / 25 mm) immediately after lamination and the maximum peel strength (N / 25 mm) after leaving the film for 1 hour after lamination were evaluated based on the following evaluation criteria. In this test, adhesion to a semiconductor silicon wafer with an uncoated surface is referred to as "bare wafer adhesion," and adhesion to a silicon wafer with a surface coated with benzocyclobutene (BCB) to a thickness of 1 μm is referred to as "BCB-coated wafer adhesion." In the "Adhesion" column of Table 1, the evaluation results based on the following evaluation criteria are shown together with the measured value of the maximum peel force immediately after lamination (α (N / 25 mm)) and the measured value of the maximum peel force after leaving it for 1 hour after lamination (β (N / 25 mm)), as "Evaluation result: α → β." - Evaluation criteria - ◎: Maximum peel force immediately after lamination was 1.0 N / 25 mm or more. ○: Maximum peel force immediately after lamination was less than 1.0 N / 25 mm, but the maximum peel force 1 hour after lamination was 1.0 N / 25 mm or more. ×: Maximum peel force 1 hour after lamination was less than 1.0 N / 25 mm. Note that the water-soluble cured film of the semiconductor processing tape produced in the examples did not peel off from the silicon wafer when the surface protection tape was peeled off in step (c) of the semiconductor chip manufacturing method of the present invention, and the water-soluble cured film also firmly adhered to the silicon wafer. Furthermore, the water-soluble uncured film of the semiconductor processing tape produced in the Examples did not peel off from the silicon wafer during grinding in step (a) of the semiconductor chip manufacturing method of the present invention, and the water-soluble uncured film also adhered firmly to the silicon wafer. On the other hand, the semiconductor processing tapes of Comparative Examples 1 and 2 had poor adhesion and could not be used as semiconductor processing tapes, so tests 2 to 6 were not performed.

[0094] <Test 2: Removability by Washing> The PET film was peeled off from each semiconductor processing tape obtained in each Example and Comparative Example, and the surface of the water-soluble uncured film was laminated to the mirror surface of a silicon wafer at a temperature of 23°C, and then the water-soluble uncured film was cured. The lamination was performed by overlapping the semiconductor processing tape on the silicon wafer and running a rubber roller with a load of 2 kg back and forth three times on the surface of the semiconductor processing tape. The curing was also performed at a power of 100 mW / cm. ２ A metal halide lamp with an intensity of 1000 mJ / cm ２ The test was performed by irradiating the water-soluble cured film with ultraviolet light. The surface protection tape was then peeled off from the water-soluble cured film. Thereafter, the silicon wafer having the water-soluble cured film was set in a spin coater (model number: manufactured by Active Co.) with the water-soluble cured film facing up, and pure water at a rotation speed of 200 rpm and a water temperature of 23°C was poured onto the water-soluble cured film at a rate of 100 mL / min for 2 minutes. After rinsing with water, it was visually confirmed whether the water-soluble cured film remained on the silicon wafer, and the result was evaluated based on the following evaluation criteria. Note that "glue" in the evaluation criteria of this test refers to a mass formed by the water-soluble cured film swelling with water. - Evaluation criteria - ◎: The water-soluble cured film dissolved and no adhesive residue remained. ◯: The adhesive residue of the water-soluble cured film was slight, to an acceptable level for a semiconductor chip. ×: The water-soluble cured film swelled, and the drain pipe (diameter 40 mm) of the spin coater became clogged.

[0095] <Test 3: Removability by washing with water after plasma treatment> The PET film was peeled off from each semiconductor processing tape obtained in each Example and Comparative Example, and the surface of the water-soluble uncured film was laminated to the mirror surface of a silicon wafer at a temperature of 23°C, and then the water-soluble uncured film was cured. The lamination was performed by overlapping the semiconductor processing tape on the silicon wafer and running a rubber roller with a load of 2 kg back and forth three times on the surface of the semiconductor processing tape. The curing was also performed at a power of 100 mW / cm ２ A metal halide lamp with an intensity of 1000 mJ / cm ２The water-soluble cured film was irradiated with ultraviolet light of 1000 nm. Next, the surface protection tape was peeled off from the water-soluble cured film, and the water-soluble cured film was then plasma-treated under the following plasma treatment conditions. Thereafter, the silicon wafer having the water-soluble cured film was set in a spin coater (model number: manufactured by Active Co., Ltd.) so that the water-soluble cured film was positioned upward, and pure water at a rotation speed of 200 rpm and a water temperature of 23°C was poured onto the water-soluble cured film at a water rate of 100 mL / min for 2 minutes. After this water rinsing, it was visually confirmed whether the water-soluble cured film remained on the silicon wafer, and the result was evaluated based on the following evaluation criteria. - Plasma Treatment Conditions - Plasma Treatment Apparatus: Model No. NVC-103, manufactured by Nippo Denshi Co., Ltd. Treatment Apparatus Output: 125 W Plasma Gas: SF ６ Treatment temperature: 60°C Treatment pressure: 0.0005 MPa Treatment time: 2 minutes - Evaluation criteria - ◎: The water-soluble cured film was dissolved and no adhesive residue was left. ◯: The adhesive residue on the water-soluble cured film was slight and acceptable for a semiconductor chip. ×: The water-soluble cured film swelled, clogging the drain pipe (diameter 40 mm) of the spin coater.

[0096] <Test 4: Heat Resistance 1 (Plasma Heat Resistance, Device Contamination Prevention)> The water-soluble uncured film of each Example and Comparative Example was attached to the mirror surface of a silicon wafer fixed on a chuck table in the same manner as in Test 5 below, and then subjected to a plasma irradiation of 100 mW / cm ２ A metal halide lamp with an intensity of 1000 mJ / cm ２The water-soluble uncured film was cured by irradiating it with ultraviolet light. Next, the surface protection tape was peeled off from the water-soluble cured film, and the exposed water-soluble cured film was subjected to plasma treatment using argon gas under the conditions of an output of 125 W, a treatment temperature of 60°C, a treatment pressure of 0.0005 MPa, and a treatment time of 2 minutes. In this way, a laminated test specimen of a silicon wafer and a water-soluble cured film was prepared. At the edge of this laminated test specimen (silicon wafer), the amount of deformation of the water-soluble cured resin composition forming the water-soluble cured film after plasma treatment was confirmed using a microscope. The amount of deformation was measured based on the target position where the water-soluble cured film was burned off by laser grooving, and the actual edge position was observed using a microscope. Furthermore, without removing the laminated test specimen from the chuck table, the presence or absence of contamination of the chuck table by the water-soluble cured resin composition forming the water-soluble cured film was confirmed. Heat resistance test 1 is a test to evaluate the deformation prevention property of the water-soluble film after the plasma dicing process and the property of not easily contaminating the equipment, specifically, the property of the water-soluble film not softening or melting due to the heat of plasma gas irradiation, protecting parts other than the target of plasma processing due to the heat of plasma gas irradiation, and the property of not easily contaminating various equipment during handling of the semiconductor processing tape. - Evaluation criteria - ◎: The deformation amount is 100 μm or less, and there is no contamination on the chuck table. ○: The deformation amount is less than 100 μm and 1000 μm or less, and there is no contamination on the chuck table. ×: The deformation amount is 1000 μm or more, or the water-soluble curable resin composition flows from the silicon wafer and contaminates the edge of the chuck table.

[0097] <Test 5: Heat Resistance 2 (Laser Heat Resistance)> The PET film was peeled off from each of the semiconductor processing tapes obtained in each Example and Comparative Example, and the surface of the water-soluble uncured film was laminated to the mirror surface of a silicon wafer at a temperature of 23°C, after which the water-soluble uncured film was cured. The lamination was performed by overlapping the semiconductor processing tape on the silicon wafer, and then rolling a rubber roller with a load of 2 kg back and forth three times on the surface of the semiconductor processing tape. The curing was also performed at a laser power of 100 mW / cm. ２ A metal halide lamp with an intensity of 1000 mJ / cm ２The water-soluble cured film was then exposed by peeling the surface protection tape from the water-soluble cured film, and the exposed film was then cut using a laser dicer DFL7160 (trade name, manufactured by Disco) to form grooves (laser grooving process). The laser grooving conditions were an output of 1 W, a frequency of 100 Hz, a processing speed of 50 mm / sec, and a groove width of 10 μm. Immediately after cutting the water-soluble cured film, the wafer portion (exposed portion of the wafer) was observed under a microscope, and the groove width of the formed grooves was measured at 10 points at a depth of 1 μm from the surface, spaced 100 μm apart along the groove length. The average value of the 10 measured widths was calculated and evaluated based on the following evaluation criteria. This test evaluates the deformation prevention properties of the water-soluble film immediately after the laser grooving process. Specifically, it is a test to evaluate a more advanced property in which the water-soluble film does not soften or melt due to the heat of laser irradiation, maintains the formed groove width, and does not flow down into the groove (exposed portion of the wafer). For Comparative Example 7, Test 4 was evaluated as "X", so Tests 5 and 6 were not conducted. - Evaluation criteria - ○: The measured width of the formed groove is within the range of 80 to 120% of the groove formation width of 10 μm △: The measured width of the formed groove is within the range of 60 to 140% of the groove formation width of 10 μm (excluding the range of 80 to 120%) ×: The measured width of the formed groove is less than 60% or more than 140% of the groove formation width of 10 μm

[0098] <Test 6: Heat Resistance 3 (Heat Resistance Over Time)> The deformation prevention properties of the water-soluble films 7 days after the laser grooving process were evaluated in the same manner as in Test 5 above, except that, after the laser grooving process, the films were left to stand in an atmosphere at 23°C and 50% RH for 7 days, and then the groove width (average value) of the grooves formed in each water-soluble cured film was measured. This test evaluates the deformation prevention properties of the water-soluble film 7 days after the laser grooving process, and specifically, it is a test to evaluate a more advanced property in which the water-soluble film does not soften or melt due to the heat of laser irradiation, maintains the formed groove width even after 7 days, and does not flow down into the grooves (exposed portions of the wafer). Note that, for Example 1, the result of Test 5 was evaluated as "X", so Test 6 was not performed.

[0099] <Test 7: Gel fraction of water-soluble cured film> A water-soluble uncured film with a PET film was prepared in the same manner as in the preparation of the water-soluble uncured film of each Example and Comparative Example. This water-soluble uncured film with a PET film was cured. The curing was carried out at 100 mW / cm ２ A metal halide lamp with an intensity of 1000 mJ / cm ２ The cured film was then irradiated with ultraviolet light of 100 .mu.m. The resulting water-soluble cured film was then peeled off from the PET film. Approximately 1 g of the water-soluble cured film was then placed in 100 g of pure water under the conditions of 30°C and 50% RH, and stirred at 300 rpm for 10 minutes. The mixture was then passed through a 100-mesh wire net to determine the mass of the components remaining on the wire net, and the ratio of this mass to the original mass was calculated to obtain the gel fraction (%).

[0100]

[0101]

[0102] The above results reveal the following: The uncured semiconductor processing tapes of Comparative Examples 1 to 4, which included a water-soluble uncured film containing water-soluble polymer A and even a plasticizer but no monomer B, did not exhibit sufficient adhesion to semiconductor wafers. Furthermore, the uncured semiconductor processing tape of Comparative Example 4 also had poor plasma heat resistance. The uncured semiconductor processing tapes of Comparative Examples 5 and 6, which included a water-soluble uncured film in which an acrylic acid ester monomer or acryloylmorpholine was used in combination with water-soluble polymer A instead of monomer B, were poor in water-rinsing removability or adhesion. The uncured semiconductor processing tape of Comparative Example 7, which included a water-soluble uncured film containing 30 parts by mass of a solvent (water) as a low-molecular-weight component, was poor in plasma heat resistance. The uncured semiconductor processing tape of Comparative Example 8, which included a water-soluble uncured film in which acryloylmorpholine was used in combination with water-soluble polymer A, was poor in adhesion, similar to Comparative Example 6.

[0103] In contrast, the uncured semiconductor processing tapes of the Examples, which include a water-soluble uncured film containing water-soluble polymer A and monomer B, exhibit sufficient adhesion to wafers having hydrophilic and hydrophobic surfaces and high water removability, allowing for rinsing with unheated water even after curing. Moreover, these semiconductor processing tapes also exhibit high heat resistance. Therefore, the uncured semiconductor processing tapes of the Examples combine heat resistance after curing with wafer adhesion in the uncured state, while also exhibiting high water removability, allowing for rinsing with unheated water even after curing. Therefore, the semiconductor processing tapes of the Examples, which correspond to the semiconductor processing tapes having the water-soluble film of the present invention, can protect the circuit surface of a semiconductor wafer during the backgrinding process and can easily perform a plasma dicing process while ensuring flexibility in process design, making them suitable for use in semiconductor chip manufacturing methods that include a plasma dicing process. In particular, the semiconductor processing tapes of Examples 2 to 12, which correspond to semiconductor processing tapes having a water-soluble film according to a preferred embodiment of the present invention, are capable of protecting the circuit surface of a semiconductor wafer in the backgrinding process, and also enable the laser grooving and plasma dicing processes to be carried out easily while ensuring flexibility in process design, making them suitable for use in semiconductor chip manufacturing methods that include the laser grooving and plasma dicing processes. It can be seen that the use of these semiconductor processing tapes in semiconductor chip manufacturing methods that include the plasma dicing process, and preferably also the laser grooving process, enables the easy manufacture of semiconductor chips with high dimensional accuracy and no chipping, while ensuring flexibility in process design.

[0104] While the present invention has been described in connection with embodiments thereof, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the claims should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0105] This application claims priority based on Japanese Patent Application No. 2024-022804, filed on February 19, 2024, the contents of which are incorporated herein by reference as part of the present specification.

[0106] REFERENCE SIGNS LIST 1 Semiconductor wafer 1A Circuit surface 1B Back surface 2 Semiconductor chip 3 Semiconductor processing tape 4 Surface protection tape 4A Base film 4B Adhesive layer 5 Water-soluble uncured film 5C Water-soluble cured film 5U Ultraviolet light 6 Laser light irradiation means 7 Laser light 8 Groove 9 Water 10 Plasma etching device 10A Plasma 11 Dicing tape 11A Base film 11B Adhesive layer 12 Ring frame 15 Pin 16 Collet

Claims

1. A heat-resistant water-soluble film formed from a curable resin composition containing a water-soluble polymer A and a monomer B having a (meth)acrylamide structure and not having a ring structure containing amide nitrogen, the film having a molecular weight of 200 or less and a content of components other than the monomer B of 10% by mass or less.

2. The water-soluble film according to claim 1, which when cured has a gel fraction of 10% or less after immersion in water at 30°C for 10 minutes.

3. The water-soluble film according to claim 1, wherein the monomer B is represented by the following formula (B1) or (B2): In formula (B1), R １ represents a hydrogen atom or an alkyl group, and R ２ and R ３ represents an alkyl group or an aryl group. ２ and R ３ do not bond to each other to form a ring structure containing N. In formula (B2), R １ represents a hydrogen atom or an alkyl group, and R ４ represents an alkylene group having 1 to 6 carbon atoms, and R ５ and R ６ represents an alkyl group or an aryl group. ５ and R ６ do not bond to each other to form a ring structure containing N.

4. The water-soluble film according to claim 1, wherein the content of said monomer B per 100 parts by mass of said water-soluble polymer A is 100 to 300 parts by mass.

5. The water-soluble film according to claim 1, for use in plasma treatment and / or laser treatment.

6. A semiconductor processing tape comprising a water-soluble film according to any one of claims 1 to 5 laminated with a surface protection tape for protecting the circuit surface of a semiconductor wafer.

7. A method for manufacturing semiconductor chips, comprising: a step (a) of grinding the back surface of a semiconductor wafer in which the water-soluble film of the semiconductor processing tape defined in claim 6 has been laminated to the circuit surface of the semiconductor wafer without heating; a step (FC) of irradiating the water-soluble film of the semiconductor processing tape with radiation from the surface protection tape side to harden the water-soluble film; a step (b) of supporting and fixing the semiconductor wafer to a dicing tape via a ring frame; a step (c) of peeling the surface protection tape of the semiconductor processing tape from the hardened water-soluble film to expose the water-soluble film; a step (d) of irradiating the hardened water-soluble film with a laser along the intended cutting area of ​​the semiconductor wafer to cut and form grooves; a step (e) of plasma-treating the semiconductor wafer from the water-soluble film side cut in step (d) to individualize the semiconductor wafer; and a step (f) of washing the cut water-soluble film with water to dissolve and remove it.

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