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

Abstract

Provided are a water-soluble film for plasma treatment that exhibits high heat resistance while achieving both sufficient adhesion to a hydrophobic surface and excellent water-washability, a semiconductor processing tape having this film, and a method for manufacturing a semiconductor chip using this semiconductor processing tape. 【Solution means】The semiconductor processing tape 3 is formed of a curable resin composition containing a water-soluble polymer and a monomer having a (meth)acrylamide structure and not having a ring structure containing amide nitrogen, and is a water-soluble uncured film 5 for plasma treatment having a molecular weight of 200 or less and a content of components other than the monomer of 10% by mass or less, and a surface protection tape. The method for manufacturing a semiconductor chip having a water-soluble uncured film and using this semiconductor processing tape includes a grinding step, a curing step of the water-soluble film, a plasma treatment step, and a water washing step for a semiconductor wafer having the water-soluble film of the semiconductor processing tape bonded to the back surface under non-heating conditions.

Description

Technical Field

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

Background Art

[0002] Various products (including semi-finished products) and their materials usually require 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 such as surface modification and various processes such as etching using plasma (plasma gas) or laser. As an example, as a means for imparting functionality to the surface layer of a semiconductor chip, there is a plasma treatment in which plasma is generated in a specific gas to perform surface modification of the semiconductor chip (IC). In addition, in the manufacture of semiconductor chips, as dicing methods for singulating semiconductor wafers (chip formation), there are a laser dicing method in which a semiconductor wafer is cut by irradiating a laser and a plasma dicing method in which a semiconductor wafer is cut by injecting a fluorine gas in a plasma state.

[0003] As a dicing method for semiconductor wafers, the generally adopted blade cut method has problems such as a relatively large blade (also referred to as a street or scribe line) width and inefficient utilization of semiconductor wafers, and the occurrence of minute chipping in semiconductor chips. In addition, in the laser dicing method, since the semiconductor wafer is finally physically split to singulate the semiconductor wafer, the occurrence of chipping cannot be effectively suppressed. Therefore, instead of the blade cut method or the laser dicing method, a plasma dicing method having the following advantages has come to be adopted. This plasma dicing method can effectively suppress the occurrence of chipping because the semiconductor wafer is divided and singulated by plasma irradiation. Moreover, since the plasma dicing method can form a street with a small width and high linearity, the semiconductor wafer can be efficiently utilized, and it has become possible to cope with the recent rapid progress in thinning and miniaturization of semiconductor chips.

[0004] However, not only in the plasma dicing method, but generally, plasma treatment is effective for surface modification, processing, etc., but on the other hand, as a side effect, it may damage the surface of the object to be processed. This is the same for laser treatment. Therefore, in laser treatment and plasma treatment, means for efficiently protecting portions that are not intended to be irradiated with laser light and portions that are not intended to be exposed to plasma gas, for example, the installation of a mask member, are employed. As a method of providing a mask member, the method of bonding a film-shaped processed product is advantageous in that a mask member can be easily provided. As a method of manufacturing a semiconductor chip by the plasma dicing method using such a film-shaped mask member, for example, a mask member including a layer of a water-soluble material is formed on the surface of a semiconductor wafer, and then a part of the mask member is decomposed and removed by irradiating the mask member with a laser. After exposing the surface of the semiconductor wafer in a part of the mask member, the semiconductor wafer exposed from a part of the mask member is cut by plasma etching to divide the semiconductor wafer into semiconductor chips (see Patent Document 1). Further, Patent Document 2 describes, as a film-shaped mask member used in a method of manufacturing a semiconductor chip to which the plasma dicing method is applied, "a film in which a surface protection tape and a water-soluble film are laminated via an ultraviolet curable adhesive layer, wherein the water-soluble film is formed by partial saponification of a water-soluble polymer and is insoluble in water at normal temperature and soluble in warm water at 60°C to 100°C."

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, after the mask member is formed as a mask member, it is required to be able to achieve both sufficient adhesion to the object to be processed and removability (also referred to as easy peelability) that allows it to be easily removed from the object to be processed for process simplification after fulfilling the function as a mask member. Here, water-solubilization of the mask member is effective as a means of enhancing the removability of the mask member. However, the surface of an object to be processed such as a semiconductor wafer may be protected by various coating agents in order to suppress damage caused by humidity, heat, etc. during the manufacturing process or in use. Such coating agents are made hydrophobic for the purpose of reducing the water permeability and have poor compatibility with a water-soluble mask member. Therefore, when the mask member is made water-soluble, although it is possible to ensure adhesion to an object to be processed whose surface where the mask member is installed exhibits hydrophilicity and removability by water washing (referred to as water wash removability), it may not exhibit sufficient adhesion to an object to be processed whose surface where the mask member is installed exhibits hydrophobicity.

[0007] Moreover, in plasma processing, since the object to be processed becomes hot due to plasma gas irradiation, the mask member used in plasma processing is also required to have sufficient heat resistance to withstand plasma processing from the viewpoint of suppressing deformation, flow, etc. of the mask member. Specifically, suitability for plasma, that is, plasma heat resistance, is required, which means being difficult to deform and suppressing flow against the heat generated by plasma gas irradiation to protect the portion to be masked.

[0008] In addition, for the mask member used in the plasma dicing method in the manufacturing method of semiconductor chips, the above-mentioned plasma heat resistance and laser process suitability are required as a heat resistance higher than this plasma heat resistance. For example, in the plasma dicing method using a mask member, usually, after removing only the portion of the mask member where the dicing is planned by a laser grooving process (laser treatment) that forms a street by laser irradiation, in the dicing process, the semiconductor wafer exposed from the street (groove) formed in the mask member is irradiated (exposed) with plasma for dicing. Therefore, in addition to plasma heat resistance, the mask member used in the plasma dicing method is also required to have a heat resistance (sometimes referred to as laser heat resistance) that is highly resistant to deformation even against the heat generated by laser irradiation. Also, in the actual manufacturing of semiconductor chips, due to specific circumstances such as ensuring the degree of freedom in process design, each process may not be carried out continuously. For example, the laser grooving process and the plasma etching process may not be carried out continuously. While being able to cope with such circumstances in actual manufacturing, in order to carry out the plasma dicing process as desired, the mask member is also required to have a heat resistance (sometimes referred to as heat resistance over time) that suppresses the deformation of the street over time even after laser irradiation. Thus, for the mask member used in the plasma dicing method, as laser process suitability, laser grooving heat resistance combining laser heat resistance and heat resistance over time is required.

[0009] However, when forming a mask member from a material with high heat resistance, there is generally a trade-off problem that the adhesion to the object to be processed, particularly the object to be processed whose surface where the mask member is installed exhibits hydrophobicity, and furthermore, the water wash removability decreases.

[0010] An object of the present invention is to provide a water-soluble film suitable as a mask member that exhibits high heat resistance while achieving both sufficient adhesion to a hydrophobic surface and excellent water-washability. Specifically, an object of the present invention is to provide a water-soluble film suitable as a mask member that exhibits both sufficient adhesion to a hydrophobic surface and excellent water-washability, and also exhibits plasma heat resistance. In a preferred embodiment of the present invention, an object is to provide a water-soluble film suitable as a mask member that exhibits both sufficient adhesion to a hydrophobic surface and excellent water-washability, and also exhibits plasma heat resistance and laser grooving heat resistance. Another object of the present invention is to provide a semiconductor processing tape having the above-described excellent water-soluble film, and a method for manufacturing a semiconductor chip using this semiconductor processing tape.

Means for Solving the Problems

[0011] As a result of intensive studies in view of the above problems, the present inventors have found that a water-soluble film is formed of 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 that by setting the molecular weight to 200 or less and the content of components other than the monomer B to 10% by mass or less, the film exhibits excellent water-wash removability based on its water solubility, sufficient adhesion to hydrophobic and hydrophilic surfaces, and high heat resistance that can withstand plasma treatment. Further, in a preferred embodiment of the water-soluble film having the above composition, it has been found that the film exhibits laser grooving heat resistance higher than the plasma heat resistance while maintaining excellent water-wash removability and sufficient adhesion. Then, by forming this water-soluble film into a semiconductor processing tape that is laminated and integrated with a surface protection tape for protecting the back surface of a semiconductor wafer in a back grinding process as a mask member for plasma dicing, it is possible to achieve both adhesion to a wide range of semiconductor wafers, heat resistance that can withstand plasma gas irradiation, and in a more preferred embodiment, laser grooving heat resistance, while being easily removable by water washing. By using this semiconductor processing tape in a method for manufacturing a semiconductor chip including a back grinding process, a plasma dicing process, a water washing process, and preferably further a laser grooving process, it has been found that a semiconductor chip can be easily manufactured. The present invention has been completed through further studies based on these findings.

[0012] The above problems of the present invention are solved by the following means. <1>A heat-resistant water-soluble film formed of 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, with 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 <1>, wherein the gel fraction after immersion in water at 30°C for 10 minutes when cured is 10% or less. <3>The water-soluble film for plasma treatment according to <1> or <2>, wherein the monomer B is represented by the following formula (B1) or formula (B2).

Chemical formula

Advantages of the Invention

[0013] The present invention can provide a water-soluble film suitable as a mask member that exhibits high heat resistance while achieving sufficient adhesion to a hydrophobic surface and excellent water-wash removability. Specifically, the present invention can provide a water-soluble film suitable as a mask member that exhibits plasma heat resistance while achieving sufficient adhesion to a hydrophobic surface and excellent water-wash removability. In a preferred embodiment of the present invention, a water-soluble film suitable as a mask member that exhibits plasma heat resistance and laser grooving heat resistance while achieving sufficient adhesion to a hydrophobic surface and excellent water-wash removability can be provided. Further, the present invention can provide a semiconductor processing tape having the water-soluble film of the present invention and a method for manufacturing a semiconductor chip using this semiconductor processing tape.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] In the present invention, when describing the content, physical properties, etc. of components by indicating a numerical range, when the upper limit value and the lower limit value of the numerical range are separately described, any upper limit value and lower limit value can be appropriately combined to form a specific numerical range. On the other hand, when describing by setting a plurality of numerical ranges represented by "~", the upper limit value and the lower limit value forming the numerical range are not limited to the specific combination described before and after "~" as a specific numerical range, and can be a numerical range obtained by appropriately combining the upper limit value and the lower limit value of each numerical range. In the present invention, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. 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, "water-soluble film" includes, unless otherwise specified, an "uncured water-soluble film" (hereinafter sometimes referred to as "water-soluble uncured film") containing monomer B having a (meth)acrylamide structure described later, and a "water-soluble film after curing" (hereinafter sometimes referred to as "water-soluble cured film") containing a cured product (polymer of monomer B) of monomer B described later by radiation irradiation. Further, the "resin composition" for forming the water-soluble film includes, unless otherwise specified, a "curable resin composition" containing monomer B having a (meth)acrylamide structure described later, and a "cured resin composition" containing a cured product (polymer of monomer B) of monomer B described later by radiation irradiation. Furthermore, in the present invention, when referring to "tape for semiconductor processing", unless otherwise specified, it includes a tape for semiconductor processing having a water-soluble uncured film as the water-soluble film (uncured tape for semiconductor processing) and a tape for semiconductor processing having a water-soluble cured film (cured tape for semiconductor processing). Here, the "uncured film", "curable resin composition", and "uncured tape" all have radiation curability, and refer to a state in which most of the monomer B contained therein is uncured, including a mode in which a part (70% by mass or less) of the monomer B is cured. Similarly, the "cured film product", "cured resin composition", and "cured tape" refer to a state in which most of the monomer B contained therein is cured, including a mode in which a part (70% by mass or less) of the monomer B is uncured. In the present invention, the "curability" may include curability due to crosslink formation including a polymer of monomer B, but usually means curability due to the polymerization reactivity of monomer B, that is, "polymerizability". Similarly, "curing" and "cured product" usually mean "polymerization" and "polymer", respectively. In the present invention, the "radiation" means light rays such as ultraviolet rays or ionizing radiation such as electron beams, 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 of a curable resin composition described later, and in the water-soluble film, the content of components other than monomer B having a molecular weight of 200 or less is 10% by mass or less. This water-soluble film usually becomes a self-supporting film depending on the film thickness. In the present invention, the self-supporting film refers to a film that can maintain its form as a film (film) even without the presence of other supports, for example, a film that can maintain its film shape.

[0018] In the film of the present invention, the film thickness is appropriately set according to the intended use and the like, and can be 1 to 800 μm, usually 100 to 800 μm. When the film of the present invention is used as a mask member for a semiconductor processing tape, the film thickness is appropriately determined in consideration of water washability, the conditions of step (f) described later, and further suppression of the occurrence of end face elution (seepage) in step (a) described later. For example, it can be 1 to 100 μm, and in terms of excellent suppression of seepage occurrence while maintaining water washability, 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 made into a long strip, but depending on the intended use and the like, it can also be made into appropriate shapes such as strip, sheet, string, etc., and further into an appropriate shape suitable for the object to be processed to be bonded, for example, a semiconductor wafer. The length and width of the film of the present invention are appropriately set. 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 excellent water washability based on water solubility, sufficient adhesion, and high heat resistance. Here, the heat resistance exhibited by the film of the present invention is heat resistance to plasma treatment. The heat resistance exhibited by the film of a preferred embodiment of the present invention includes not only heat resistance to plasma treatment but also heat resistance to laser treatment, for example, both laser grooving heat resistance (laser heat resistance and heat resistance over time). The film of the present invention can be suitably used for various products and their materials that are subjected to plasma treatment and / or laser treatment (laser grooving process) by utilizing the above excellent characteristics.

[0021] The water-soluble film of the present invention, particularly the water-soluble cured film, has heat resistance that can withstand a high-temperature environment by plasma treatment. Taking advantage of this property, it is suitably used as a surface protection member (plasma treatment mask member) of an object to be treated (from the plasma gas) during plasma treatment. Examples of plasma treatment include treatments using various plasma gases. Examples of plasma gases include fluorine-based gases, oxygen-based gases, argon-based gases, etc. Examples of plasma treatment include plasma dicing treatment in a semiconductor chip manufacturing method, desmear treatment for burning off fine dust on the chip surface, and atmospheric pressure plasma treatment for enhancing the reactivity between the chip surface and another member. Among them, plasma dicing treatment in a semiconductor chip manufacturing method is preferably mentioned. As the plasma heat resistance exhibited by the film of the present invention, for example, it has resistance to plasma treatment under the conditions of output 0.1 to 300 W (preferably 10 W), temperature 10 to 100 °C, pressure 0.00001 to 0.05 MPa (preferably 0.1 MPa), and treatment time 0.1 to 60 minutes, and preferably has resistance under the conditions of the plasma dicing process described later (the plasma heat resistance of Test 4). Plasma resistance means that the film of the present invention is not easily deformed such as softened or melted by the irradiation of plasma gas and retains its shape.

[0022] The water-soluble film of the present invention, particularly the water-soluble cured film, in a preferred embodiment of the present invention, has a higher degree of heat resistance that can withstand a high-temperature environment by laser treatment. Taking advantage of this property, it is suitably used as a surface protection member (laser treatment mask member) of an object to be treated (from the laser light) during laser treatment. Examples of laser treatment include treatments using various laser lights. The laser light is not particularly limited, and examples include excimer lasers, CO2 lasers, etc. Examples of laser treatment include laser grooving treatment (process) in a semiconductor chip manufacturing method, laser cutting treatment for altering silicon, laser marking treatment, etc. Among them, laser grooving treatment in a semiconductor chip manufacturing method is preferably mentioned. As the laser heat resistance shown by a preferred embodiment of the film of the present invention, for example, it has resistance to laser processing under the conditions of output of 0.1 to 10 W, frequency of 0.1 to 100 kHz, and processing feed rate of 0.1 to 800 mm / second (preferably 50 mm / second), and preferably has resistance (Test 5) under the conditions of the laser grooving process described later. These resistances mean that the film in a preferred embodiment of the present invention is not easily deformed such as softened or melted by laser irradiation and retains its shape. In addition, as the heat resistance over time, it is preferable to show resistance (Test 6) to retain the shape at the time of laser processing until about 14 days after the laser processing under the above conditions.

[0023] The water-soluble film of the present invention utilizes the above-mentioned high heat resistance and is used as a mask member for laser grooving (laser processing) and / or plasma dicing (plasma processing) of a semiconductor processing tape described later, and can be suitably used in a method for manufacturing a semiconductor chip 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 into a semiconductor processing tape as a mask member and used in a method for manufacturing a semiconductor chip including a plasma dicing step, the back surface of the semiconductor wafer can be protected from plasma processing (plasma gas and high temperature state), and moreover, deformation (softening) and flow of the mask 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 not easily deformed by the heat generated by plasma gas irradiation in the plasma dicing step and can suppress flow. Further, when the water-soluble film of a preferred embodiment of the present invention is incorporated into a semiconductor processing tape as a mask member and used in a method for manufacturing a semiconductor chip including a laser grooving step, the back surface of the semiconductor wafer can be protected from the high-temperature state caused by laser irradiation, and moreover, deformation (softening) and flow of the mask 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 less likely to be deformed even by the heat generated by plasma gas irradiation in the plasma dicing step, and furthermore, it is less likely to be deformed even by the heat generated by laser irradiation in the laser grooving step, and moreover, it also exhibits heat resistance over time that suppresses deformation over time of the streets formed in the laser grooving step.

[0024] The water-soluble film of the present invention has water solubility in both the uncured state and the cured state, and moreover, even after being laser-treated and / or plasma-treated in the cured state. The water solubility exhibited by the water-soluble film may be water solubility that dissolves in water at an appropriate temperature, but preferably has water solubility in non-heated water (usually pure water), for example, water at less than 60°C, preferably water at 40°C or lower. The lower limit value of the water temperature is not particularly limited, but can usually be 15°C, preferably 20°C. In the present invention, specifically, the water solubility of the water-soluble film is defined as the property that the water-soluble film dissolves in water and can be removed without residue within the tolerance in the water washing removability test (Test 2 and Test 3) in the examples. When such a water-soluble film exhibiting water solubility is incorporated into a semiconductor processing tape as a mask member and used in a method for manufacturing a semiconductor chip, it can be easily removed after functioning as a mask member.

[0025] The water-soluble film of the present invention exhibits sufficient adhesion to both hydrophobic and hydrophilic surfaces, whether in the uncured state or the cured state. The adhesion is a highly characteristic property that passes the adhesion test (Test 1) described in the examples below. When a water-soluble film exhibiting such adhesion is incorporated into a semiconductor processing tape as a mask member and used in a method for manufacturing a semiconductor chip including a backgrinding process, it adheres to a semiconductor wafer having a wide range of surface properties by the water-soluble uncured film and can protect the back surface of the semiconductor wafer during the backgrinding process. Moreover, even after curing (water-soluble cured film), the adhesion to the semiconductor wafer (back surface) is maintained, and the back surface can be protected.

[0026] The film of the present invention exhibits high heat resistance while maintaining excellent water-wash removability and sufficient adhesion. Further, the water-soluble film of the present invention is less likely to transfer the material 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 implementation of each process, and can prevent contamination of the devices.

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

[0028] (Water-soluble polymer A) The water-soluble polymer A contained in the water-soluble film is usually a water-soluble polymer. The water solubility exhibited by the water-soluble polymer A is not particularly limited as long as the water-soluble film can exhibit the above 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, polyvinyl pyrrolidone, poly(2-ethyl-2-oxazoline), etc. can be used. Polyvinyl alcohol may be saponified according to the water solubility required for the water-soluble film. The water-soluble polymer A is preferably a non-crosslinked product that does not crosslink alone in terms of water solubility, and sufficient water solubility is exhibited by using the 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. Thereby, adhesiveness and water-washing removability can be imparted to the water-soluble film. The weight average molecular weight of the water-soluble polymer A is more preferably 200,000 to 3,000,000, still more preferably 300,000 to 2,000,000, and particularly preferably 300,000 to 1,000,000 in terms of being able to balance adhesiveness and water-washing removability at a high level. The weight average molecular weight of the water-soluble polymer A is the value measured by the method described in the examples. When the water-soluble polymer A is specified by the degree of polymerization, although it depends on the molecular weight of each constituent component (monomer) constituting the water-soluble polymer A, for example, it can be 200 to 10,000.

[0029] (Monomer B) The monomer B contained in the water-soluble uncured film is a monomer having a (meth)acrylamide structure and not having a ring structure containing amide nitrogen, and has radiation polymerizability. Monomer B is a polymerizable compound having a molecular structure in which an oxygen atom of a (meth)acryloyl group is directly bonded to a nitrogen atom of an acyclic amino group. Here, the acyclic amino group means an amino group in which the nitrogen atom has two substituents as independent groups. Specifically, it means an amino group in which two substituents possessed by the nitrogen atom bonded to the oxygen atom of the (meth)acryloyl group are not bonded to each other to form a ring structure containing the nitrogen atom, and for example, it does not include an amino group composed of a cyclic amine compound such as pyrrolidine, morpholine, thiomorpholine, etc. The two substituents possessed by the acyclic amino group are not particularly limited, and appropriate substituents can be adopted, but R in the following formula (B1) 2 is preferably a group that can be taken. 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 achieve high levels of adhesion, water-wash removability, and heat resistance, and is more preferably a monomer represented by the following formula (B2) in that it can further enhance adhesion while maintaining excellent water-wash removability and heat resistance.

Chemical formula

[0031] In formula (B1), R 1 represents a hydrogen atom or an alkyl group, and a hydrogen atom is preferred. R 1 The alkyl group that can be taken as may be linear, branched, or cyclic, but a linear chain is preferred in terms of adhesion, water-wash removability, and heat resistance. The number of carbon atoms of the alkyl group is not particularly limited, 1 to 6 is preferred, 1 to 4 is more preferred, and 1 is even more preferred. R 2 and R 3 each represent an alkyl group or an aryl group, and an alkyl group is preferred. R 2 and R 3The alkyl group that can be used may be linear, branched, or cyclic, but a linear alkyl group is preferred in terms of adhesion, water-wash removability, and heat resistance. The number of carbon atoms in the alkyl group is not particularly limited, and in terms of achieving high levels of adhesion, water-wash removability, and heat resistance simultaneously, 1 to 12 is preferred, 1 to 8 is more preferred, and 1 to 4 is even more preferred. R 2 and R 3 The aryl group that can be used is not particularly limited, and examples include aryl groups having 6 to 24 carbon atoms. An aryl group having 6 to 10 carbon atoms is preferred, and an aryl group having 6 carbon atoms is more preferred. R 2 and R 3 are both preferably alkyl groups in terms of achieving high levels of adhesion, water-wash removability, and heat resistance simultaneously. R 2 and R 3 may be the same or different. However, R 2 and R 3 do not combine with 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 is the same as R 1 in formula (B1). R 4 represents an alkylene group having 1 to 6 carbon atoms. The alkylene group that can be used for R 4 may be linear, branched, or cyclic, but a linear alkylene group is preferred in terms of adhesion, water-wash removability, and heat resistance. The number of carbon atoms in the alkylene group is not particularly limited, and in terms of achieving high levels of adhesion, water-wash removability, and heat resistance simultaneously, 1 to 12 is preferred, 1 to 8 is more preferred, and 2 to 4 is even more preferred. R 5 and R 6 represent an alkyl group or an aryl group, and an alkyl group is preferred. The alkyl group and aryl group that can be used for R 5 and R 6 are the same as the alkyl group and aryl group that can be used for R 2 and R 3 in formula (B1), respectively. However, R 5 and R 6They do not combine with 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. Such substituents include appropriate substituents, for example, 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, and a 5-membered or 6-membered heterocyclic group is preferred. The heterocyclic group includes an aromatic heterocyclic group and an aliphatic heterocyclic group.), an alkoxy group, and the like.

[0034] (Cured product of monomer B) The water-soluble cured film contains the cured product of the above 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 and a monomer other than monomer B.

[0035] (Monomer other than monomer B) The water-soluble uncured film of the present invention may contain a monomer other than monomer B (also referred to as other monomers) as long as the water solubility is not impaired. Other monomers may be any monomers that can polymerize with monomer B. For example, polymerizable compounds having an ethylenically unsaturated group can be mentioned. Specifically, (meth)acrylic acid compounds, (meth)acrylic acid ester compounds, styrene compounds, and vinyl compounds can be mentioned.

[0036] (Plasticizer) It is preferable that the water-soluble film contains a plasticizer because it can further enhance the adhesion while maintaining excellent water-wash removability and heat resistance. As the plasticizer, those usually used in the polymerizable composition can be used, and low-molecular compounds having a molecular weight of 800 or less are preferably mentioned. This low-molecular compound is preferably a low-molecular polymer, more preferably a water-soluble low-molecular polymer. The water solubility exhibited by the water-soluble low-molecular polymer is not particularly limited as long as the water-soluble film can exhibit the above water solubility. The low-molecular compound is not particularly limited, but preferably, polyvinyl alcohol and polyethylene glycol can be used. The low-molecular compound is preferably a compound that does not undergo a chemical reaction such as a crosslinking reaction with the water-soluble compound A in terms of water solubility. The molecular weight (weight-average molecular weight or number-average molecular weight in the case of a polymer) of the low-molecular compound is 800 or less. By setting the molecular weight of the low-molecular compound used in combination with the water-soluble polymer A and the monomer B or its polymer to 800 or less, adhesion, water-wash removability, and heat resistance can be balanced at a high level. The molecular weight of the low-molecular compound is preferably 100 to 800, more preferably 200 to 800, still 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 compound (polymer) is a value measured in the same manner as the weight-average molecular weight of the water-soluble polymer A. In addition, when the low-molecular compound (polymer) is specified by the degree of polymerization, although it depends on the molecular weight of each constituent component constituting the low-molecular compound, for example, it can be set to 5 to 20.

[0037] (Component with a molecular weight of 200 or less) The water-soluble film may contain components with a molecular weight of 200 or less, other than monomer B with a molecular weight of 200 or less (in the present invention, sometimes referred to as "low molecular weight components"). This low molecular weight component is preferably a component that does not correspond to any of those with a molecular weight of 200 or less among the above plasticizers and those with a molecular weight of 200 or less among the following other components. Examples of the low molecular weight component 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 a certain component is 0.1% by mass or less.

[0038] (Other components) The water-soluble film may contain a component that does not correspond to any of the water-soluble polymer A, monomer B or cured product of monomer B, other monomers, and plasticizer. For example, examples of other components include ultraviolet absorbers, radical initiators, surfactants, labeling materials, silane coupling agents, etc. Both the ultraviolet absorber and the radical initiator can be used without particular limitation as known ones. Examples of the ultraviolet absorber include benzophenone, benzotriazole, hydroxyphenyltriazine, etc., and benzotriazole and hydroxyphenyltriazine are 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. In addition, 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 components that decompose or disappear due to curing. In addition, the content of each component in the curable resin composition is not particularly limited as long as it satisfies the content of each component in the water-soluble cured film when the water-soluble uncured film is formed, and can be appropriately determined. Preferably, it is the same as the content of each component in the water-soluble cured film. The content of each component in the cured 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 components that decompose or disappear by curing.

[0040] The contents of the water-soluble polymer A, monomer B, and other monomers in the water-soluble uncured film are not particularly limited and are appropriately determined. In the water-soluble uncured film, the total content of the content of the water-soluble polymer A, the content of monomer B, and the content of other monomers is preferably 40 to 100% by mass, more preferably 60 to 95% by mass, in terms of adhesion, water-washing removability, and heat resistance. The content of monomer B in the water-soluble uncured film is more preferably 20 to 500 parts by mass with respect to 100 parts by mass of the water-soluble polymer A. When the content of monomer B is 500 parts by mass or less, the adhesion can be further enhanced while maintaining excellent water-washing removability and heat resistance. On the other hand, when the content of monomer B is 20 parts by mass or more, the adhesion and heat resistance can be further enhanced while maintaining excellent water-washing removability. The heat resistance can be further improved to exhibit laser grooving heat resistance. As a result, in terms of the point where adhesion, water-washing removability, and heat resistance can be well balanced at a high level (a preferred embodiment of the present invention), the content of monomer B is more preferably 40 to 400 parts by mass with respect to 100 parts by mass of the water-soluble polymer A, still more preferably 100 to 300 parts by mass, and particularly preferably 150 to 250 parts by mass.

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

[0042] The total content of the water-soluble polymer A, monomer B, other monomers, and plasticizer in the water-soluble uncured film is not particularly limited and is appropriately determined. The above total content is preferably, for example, 60 to 100% by mass, and more preferably 80 to 100% by mass. The content of the plasticizer in the water-soluble uncured film is not particularly limited and is appropriately determined. For example, the content of the plasticizer is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the water-soluble polymer A, and more preferably 10 to 100 parts by mass, and still more preferably 20 to 50 parts by mass, in terms of being able to achieve high levels of adhesion, water-wash removability, and heat resistance. The content of the plasticizer in the water-soluble uncured film and the curable resin composition, and the content of the plasticizer in the water-soluble cured film and the cured resin composition are each set within the above range, and preferably have the same content.

[0043] The content of the low-molecular-weight component in the water-soluble uncured film is 10% by mass or less. A water-soluble film with a low-molecular-weight component content of 10% by mass or less can form a self-supporting film depending on the film thickness, has excellent handleability, and can suppress volatilization, etc. during the use of the low-molecular-weight component. Also, contamination of the equipment can be prevented. The content of the above low-molecular-weight component is preferably 3% by mass or less, and more preferably 1% by mass or less, in terms of effectively suppressing volatilization during the use of the low-molecular-weight component, further heat resistance, and equipment contamination, etc. The content of the low-molecular-weight component in the resin composition is not particularly limited and can be appropriately determined. For example, it can be within the range of the above 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 appropriately determined. For example, the content of the ultraviolet absorber in the water-soluble film is appropriately determined according to the content of monomer B, and further the absorbance of the water-soluble film, etc. For example, it can be 0.5 to 35 parts by mass, preferably 0.5 to 15 parts by mass, and more preferably 1 to 13 parts by mass with respect to 100 parts by mass of the water-soluble polymer A. The content of the radical initiator in the water-soluble uncured film and the curable resin composition is appropriately determined according to the content of monomer B, the content of other monomers, and further the absorbance of the water-soluble cured film, etc. For example, it can be 0.5 to 25 parts by mass, preferably 0.5 to 15 parts by mass, and more preferably 1 to 13 parts by mass with respect to 100 parts by mass of the water-soluble polymer A.

[0045] The water-soluble cured film preferably has a gel fraction of 10% or less when stirred (rotation speed 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 water washing removability is improved, and the residual of the water-soluble film in a swollen state or the paste residue can be effectively reduced in step (f) described later. Also, contamination of the apparatus can be prevented. From the viewpoint of further improving the water washing removability, 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 the value measured by the method and conditions described in the examples.

[0046] The absorbance of the water-soluble film with respect to electromagnetic waves having 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 according to the type and content of the above ultraviolet absorber. In the present invention, the electromagnetic wave refers to those that are electromagnetic waves among the radiations described later, and includes, for example, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays (γ rays). The absorbance shall be the value measured by the following measurement method. That is, for the water-soluble cured film formed on a PET film (thickness: 38 μm), using the spectrophotometer U-5100 (manufactured by YAMATO SCIENTIFIC CO., LTD.) with the above PET film as a reference, the absorbance is measured in the wavelength range of 300 to 1000 nm. The absorbance at a wavelength of 355 nm is obtained and taken as the absorbance of the water-soluble film.

[0047] [Tape for semiconductor processing] The tape for semiconductor processing of the present invention is a laminated tape having the water-soluble film of the present invention described above and a surface protection tape for protecting the back surface of a semiconductor wafer. Regarding the tape for semiconductor processing of the present invention and the method for manufacturing a semiconductor chip, focusing on the water-soluble film, it is preferably used in the following steps (a) (grinding step), step (e) (plasma dicing step), and step (f) (water washing step). A tape for semiconductor processing according to a preferred embodiment of the present invention is preferably used in step (a), step (d) (laser grooving step), optionally step (e), and step (f). Therefore, the tape for semiconductor processing of the present invention can also be referred to as a tape for semiconductor wafer processing. The uncured tape for semiconductor processing is a tape having a layer structure in which a water-soluble uncured film and a surface protection tape are laminated and integrated. Since the surface protection tape and the water-soluble uncured film are integrated in this uncured tape for semiconductor processing, when used in the method for manufacturing a semiconductor chip, the surface protection tape and the water-soluble uncured film can be bonded to the semiconductor wafer at once, improving the working efficiency. On the other hand, the cured tape for semiconductor processing is a tape having a layer structure in which a water-soluble cured film and a surface protection tape are laminated and integrated. The tape for semiconductor processing of the present invention only needs to have the above configuration, and other configurations are not particularly limited. For example, a protective layer or the like may be provided on the surface of the water-soluble film and / or the surface protection tape. Further, the film or each layer such as the water-soluble film and the surface protection tape may have a single-layer structure or a multi-layer structure of two or more layers.

[0048] The surface protection tape of the semiconductor processing tape of the present invention is difficult to achieve sufficient adhesion to a wide semiconductor wafer, excellent water-wash removability, and high heat resistance at the same time, and it is also difficult to exhibit laser grooving characteristics. Therefore, in order to manufacture semiconductor chips using it as a semiconductor processing tape, in addition to the surface protection tape, a mask member for protecting the back surface of the semiconductor wafer from plasma treatment, preferably laser grooving treatment, is required. The semiconductor processing tape of the present invention has a surface protection tape and a water-soluble film exhibiting the above excellent characteristics integrally laminated, and the surface protection tape and the water-soluble film can be functionally differentiated. As a result, when using the semiconductor processing tape of the present invention, it is possible to perform the attachment of the surface protection tape and the attachment of the mask member at one time, and semiconductor chips can be manufactured simply.

[0049] As shown in FIG. 1, the 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 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 according to the application and the like. For example, the total thickness (the total thickness of each layer) of the semiconductor processing tape can be 100 to 800 μm.

[0051] The semiconductor processing tape of the present invention is usually made into a long strip, but depending on the application and the like, it can also be made into a strip shape, a sheet shape, a string shape, etc., and further into an appropriate shape suitable for the semiconductor wafer to be bonded. The length and width of the semiconductor processing tape are appropriately set. 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 manufactured, for example, by preparing a water-soluble film and a surface protection tape, laminating them, and adhering them with an adhesive layer.

[0052] By having the above configuration, the tape for semiconductor processing of the present invention exhibits water washability, adhesion, and heat resistance in the form of an uncured tape for semiconductor processing, and maintains these properties in the form of a cured tape for semiconductor processing.

[0053] In the tape for semiconductor processing having the above layer structure, the peel strength (180° peel strength at 23°C) between the water-soluble film and the surface protection tape (when the surface protection tape has an adhesive layer, the adhesive layer) is such that it does not peel while maintaining adhesion in the step (a) of grinding the back surface of the semiconductor wafer, and 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 strength is not uniquely determined, but from the viewpoint of the peelability of the surface protection tape from the water-soluble cured film, its upper limit value is preferably, for example, 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 in the grinding step, its lower limit value is preferably, for example, 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 strongly to the water-soluble uncured film with a peel strength that satisfies, for example, the above lower limit value, while the adhesive layer after curing preferably has a peel strength that satisfies, for example, the above upper limit value. The water-soluble film having the above composition usually exhibits a peel strength of 0.1 N / 25 mm with respect to the adhesive layer of the surface protection tape, and this peel strength can be appropriately set by changing the composition of the water-soluble film or the adhesive layer. The peel strength shall be the value measured by the following measurement method. That is, the tape for semiconductor processing of the present invention is cut out to a width of 25 mm, and using a Strograph VG1F (trade name, manufactured by Toyo Seiki Co., Ltd.), at 23 °C, with a peel angle of 180° and a peel speed of 300 mm / min, the maximum peel strength when peeling the water-soluble film and the surface protection tape (adhesive layer) is measured. Conditions other than the above conditions shall comply with Japanese Industrial Standard (JIS) Z 0237:2009. The maximum peel strength (N / 25 mm) thus obtained shall be defined as the peel strength of the tape for semiconductor processing (N / 25 mm).

[0054] (Surface protection tape) The surface protection tape can be used without particular limitation as long as it is commonly used in the method for manufacturing semiconductor chips. The surface protection tape has a function of protecting the circuit surface of a semiconductor wafer in the method for manufacturing semiconductor chips, particularly in the back grinding 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 preferable surface protection tape 4 has a two-layer structure having an adhesive layer 4B on the surface of a base film 4A as shown in FIG. 1. It may have a protective layer or the like in addition to the base film and the adhesive layer. The base film and the adhesive layer may each have a single-layer structure or a multi-layer structure of two or more layers. The total thickness (total thickness of each layer) of the surface protection tape 4 is not particularly limited, and can be, for example, 100 to 800 μm.

[0055] The material for forming the base film is not particularly limited, and for example, homopolymers or copolymers of α-olefins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, or mixtures thereof, such as polyolefin resins, engineering plastics such as polyethylene terephthalate, polycarbonate, polymethyl methacrylate, thermoplastic elastomers such as polyurethane, styrene-ethylene-butene-styrene, or pentene-based copolymers, etc. are preferably used. The base film can be manufactured using a general extrusion method. Also, when obtaining it by laminating various resins, co-extrusion methods, lamination methods, etc. can be applied. At this time, an adhesive layer may be provided between the resins, as is usually done in the manufacturing method of ordinary laminated films. From the viewpoints of strength and elongation characteristics and radiation transparency, the thickness of the base film is preferably 30 to 200 μm.

[0056] The adhesive layer may be any layer containing an adhesive, for example, it can be formed using an adhesive composition. The adhesive composition is not particularly limited, and examples thereof include compositions containing ordinary adhesives such as (meth)acrylic, rubber, and silicone adhesives. From the viewpoints of weather resistance and price, etc., (meth)acrylic adhesives are preferably used. Examples of the (meth)acrylic adhesive include compositions containing a copolymer having (meth)acrylate as a constituent component (hereinafter referred to as “(meth)acrylate copolymer”) as an adhesive component. This composition may contain a curing agent, etc. described later in addition to the (meth)acrylate copolymer.

[0057] Examples of the (meth)acrylate which is a constituent component of the above (meth)acrylate copolymer include alkyl acrylates or alkyl methacrylates having a linear or branched alkyl group with 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)acrylate may be used alone or in combination of two or more. In the constituent components of the (meth)acrylate copolymer, the content of the above (meth)acrylate component is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95 to 99.9% by mass.

[0058] The above (meth)acrylic acid ester copolymer may contain constituent components other than the above (meth)acrylic acid ester (also referred to as other constituent components). Examples of other constituent 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)acrylate (preferably those in which the alkyl group of the above (meth)acrylic acid ester is substituted with a hydroxy group); sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate; (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, alkylaminoalkyl (meth)acrylate (e.g., dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, etc.), N-vinylpyrrolidone, acryloylmorpholine, vinyl acetate, styrene, acrylonitrile, and the like. These constituent components may be used alone or in combination of two or more kinds.

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

[0060] (Meta)acrylic adhesives may contain a curing agent, which is not particularly limited. For example, the curing agents described in JP-A-2007-146104 can be used. For example, 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, N,N,N,N'-tetraglycidyl-m-xylenediamine; isocyanate compounds having two or more isocyanate groups in the molecule such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate; aziridine compounds having two or more aziridinyl groups in the molecule such as tetramethylol-tri-β-aziridinylpropionate, trimethylol-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-(2-methylaziridine)propionate, etc. can be mentioned. The content of the curing agent may be adjusted according to the desired adhesive strength. With respect to 100 parts by mass of the above (meta)acrylic ester copolymer, 0.01 to 10 parts by mass is preferable, and 0.1 to 5 parts by mass is more preferable.

[0061] (Meta)acrylic adhesives can also be radiation-curable adhesives that contain a photopolymerizable compound and a photoinitiator in addition to the above adhesive components. By containing the adhesive component, the photopolymerizable compound, and the photoinitiator, it can be cured by irradiation with radiation (preferably ultraviolet rays), and the adhesive strength of the adhesive layer can be reduced. As such a photopolymerizable compound, for example, low molecular weight compounds having at least two or more photopolymerizable carbon-carbon double bonds in the molecule that can be three-dimensionally crosslinked by light irradiation, as described in JP-A-60-196956 and JP-A-60-223139, and oligomers obtained by polymerizing them can be used. The photopolymerizable compound is not particularly limited. For example, 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 or 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 (an adduct of (meth)acrylic acid with an epoxy compound), polyester (meth)acrylate (an adduct of (meth)acrylic acid with a polyester), and urethane (meth)acrylate (an adduct of (meth)acrylic acid with a urethane) are used. The photoinitiator is not particularly limited. For example, the photoinitiators described in JP-A-2007-146104 or JP-A-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-hydroxymethyl phenyl propane, etc. can be used.

[0062] As the radiation-curable pressure-sensitive adhesive, in addition to the combination of the above (meth)acrylate copolymer and a low molecular weight compound having at least two or more radiation-polymerizable carbon-carbon double bonds in the molecule, a copolymer having a (meth)acrylate as a constituent component, and a repeating unit constituting this copolymer having a radiation-polymerizable carbon-carbon double bond (meth)acrylic copolymer (hereinafter referred to as "radiation-polymerizable (meth)acrylic copolymer") is also preferably used. A radiation-polymerizable (meth)acrylic copolymer is a copolymer having a reactive group capable of undergoing a polymerization reaction upon irradiation with radiation, particularly ultraviolet rays, in the molecule of the copolymer. Such a reactive group is an ethylenically unsaturated group, that is, a group having a carbon-carbon double bond (ethylenically unsaturated bond), and examples thereof include a vinyl group, an allyl group, a styryl group, a (meth)acryloyloxy group, a (meth)acryloylamino group, and the like. The radiation-polymerizable (meth)acrylic copolymer is not particularly limited. For example, a (meth)acrylic copolymer having a functional group a, a compound having a functional group b capable of reacting with the functional group a and a radiation-polymerizable carbon-carbon double bond (hereinafter referred to as "radiation-polymerizable compound having a functional group b") are reacted to obtain a (meth)acrylic copolymer. Examples of the (meth)acrylic copolymer having a carbon-carbon double bond include the same materials as those described in paragraphs

[0036] to

[0055] of JP-A-2014-192204.

[0063] In the above radiation-polymerizable compound having a 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, an isocyanate group, and the like. Specific examples of the radiation-polymerizable compound having a 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-methylolacrylamide, N-methylolmethacrylamide, 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, a urethanized product of a part of the isocyanate group of a polyisocyanate compound with a monomer having a hydroxyl group or a carboxyl group and a radiation-polymerizable carbon-carbon double bond, and the like. In the reaction of the (meth)acrylic copolymer having the above functional group a and the radiation-polymerizable compound having the above functional group b, by leaving unreacted functional groups, the acid value, hydroxyl value, etc. can be appropriately set.

[0064] The above radiation-polymerizable (meth)acrylic copolymer can be obtained by solution polymerization in various solvents. As the organic solvent in the case of solution polymerization, ketone-based, ester-based, alcohol-based, and aromatic-based solvents can be used. Generally, it is preferable to use a solvent with a boiling point of 60 to 120°C, which is a good solvent for acrylic polymers. For example, toluene, ethyl acetate, isopropyl alcohol, benzene, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, etc. can be used. As the polymerization initiator, radical generators such as azobis-based ones like α,α'-azobisisobutyronitrile and organic peroxide-based ones like benzoyl peroxide can be used. At this time, a catalyst and a polymerization inhibitor can be used in combination as necessary, and by adjusting the polymerization temperature and polymerization time, a copolymer with a desired molecular weight can be obtained. Note that the synthesis method is not limited to solution polymerization, and other methods such as bulk polymerization and suspension polymerization are also acceptable.

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

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

[0067] The thickness of the pressure-sensitive adhesive layer is not particularly limited as long as it does not prevent adhesion to the water-soluble film and does not allow the intrusion of dust or grinding water during grinding. Usually, 5 to 100 μm is appropriate.

[0068] [Method for manufacturing a semiconductor chip] Next, the method for manufacturing a semiconductor chip of the present invention (hereinafter sometimes simply referred to as "the manufacturing method of the present invention") has the following steps, and by subjecting a semiconductor wafer to the processes of each step, a semiconductor chip can be easily manufactured. Therefore, the method for manufacturing a semiconductor chip of the present invention can also be said to be a method for processing a semiconductor wafer. The manufacturing method of the present invention is a method of sequentially performing the following steps (a) to (f) in this order, and before step (a), between each step, and after step (f), other steps adopted in the method for manufacturing a semiconductor chip can also be appropriately performed. In the present invention, step (FC) is performed before step (b) in consideration of handleability, manufacturing workability, etc., but it can also be performed after step (b), that is, after being fixed to the dicing tape. Step (a): Grinding the back surface of the semiconductor wafer obtained by laminating the water-soluble film in the semiconductor processing tape of the present invention on the circuit surface of the semiconductor wafer without heating. Step (FC): A step of irradiating the water-soluble film in the semiconductor processing tape with radiation from the surface protection tape side to cure the water-soluble film. Step (b): A step of supporting and fixing the semiconductor wafer obtained in step (FC) to the dicing tape via a ring frame. Step (c): A step of peeling the surface protection tape in the semiconductor processing tape from the water-soluble cured film (water-soluble cured film) after curing to expose the water-soluble cured film. Step (d): A step of irradiating a laser along the planned cutting region of the semiconductor wafer on the water-soluble cured film to cut and provide grooves. Step (e): A step of subjecting the semiconductor wafer to plasma treatment from the side of the cut water-soluble cured film to individualize the semiconductor wafer. Step (f): A step of washing the cut water-soluble cured film with water to dissolve and remove it. Step (d): A step of irradiating a laser along the planned cutting region of the semiconductor wafer on the water-soluble cured film to cut and provide grooves. Step (e): A step of subjecting the semiconductor wafer to plasma treatment from the side of the cut water-soluble cured film to individualize the semiconductor wafer. Step (f): A step of washing the cut water-soluble cured film with water to dissolve and remove it. Step (d): A step of irradiating a laser along the planned cutting region of the semiconductor wafer on the water-soluble cured film to cut and provide grooves. Step (e): A step of subjecting the semiconductor wafer to plasma treatment from the side of the cut water-soluble cured film to individualize the semiconductor wafer. Step (f): A step of 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 referred to as a pattern surface) on one side, on which a circuit of a semiconductor element or the like is formed. Examples thereof include a silicon wafer, a SiC wafer, a GaAs wafer, and a GaN wafer. In the present invention, the circuit surface refers to the surface of a semiconductor wafer on which a pattern such as a circuit of a semiconductor element is formed, and the back surface refers to the surface (non-circuit surface) on the opposite side of the circuit surface where no circuit or the like is formed. This circuit surface has lattice-shaped streets in a plan view. Here, a street refers to a cutting line of a 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 adhered are not limited to hydrophilicity, and can also be hydrophobic. The treatment for hydrophobizing the surface of the semiconductor wafer is not particularly limited, and examples thereof include a treatment of applying a hydrophobic coating agent, a treatment by sputtering, etc. Examples of the hydrophobic coating agent applied to the surface of the semiconductor wafer include benzocyclobutene.

[0070] In the manufacturing method of the present invention, for the treatments other than the treatments related to the semiconductor processing tape of the present invention, the treatments in the normal manufacturing method of semiconductor chips can be applied without particular limitation. The devices and materials used in the manufacturing method of the present invention can be used without particular limitation those conventionally used for processing or treating semiconductor wafers, and the usage conditions of the devices can be set as appropriate.

[0071] The manufacturing method of the present invention will be specifically described with reference to the drawings, centering on the treatments related to the semiconductor processing tape of the present invention. In the following description and drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted. FIGS. 2 to 4 are schematic longitudinal sectional views (cross-sectional views cut along the thickness direction along the diameter direction of the 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 water-soluble uncured film 5 of the semiconductor processing tape (uncured semiconductor processing tape) 3 of a preferred embodiment of the present invention is laminated with the semiconductor wafer 1 so as to contact the back surface 1A of the semiconductor wafer 1, and they are bonded together under non-heating conditions. In the present invention, "under non-heating conditions" means, for example, a temperature below 60°C, preferably a temperature of 40°C or lower. The lower limit temperature is not particularly limited, but can usually be 15°C, preferably 20°C. The bonding method of the semiconductor processing tape 3 and the semiconductor wafer 1 can be applied without particular limitation using an ordinary method. However, since the water-soluble uncured film 5 has sufficient adhesion (adhesive property) to the semiconductor wafer 1, it can be bonded simply by laminating and, if necessary, applying further pressure. At the time of bonding, a semiconductor processing tape 3 having the same size or a smaller size as the semiconductor wafer 1 is used so as not to protrude to the outer peripheral side of the semiconductor wafer 1 in a state of being bonded to the semiconductor wafer 1. Thereby, for example, in the singulation step (e) described later, damage to the semiconductor processing tape 3 (water-soluble cured film 5C) protruding from the semiconductor wafer 1 due to plasma ablation can be prevented.

[0073] Next, for the semiconductor wafer 1 obtained in this way, in which the water-soluble uncured film 5 in the semiconductor processing tape 3 shown in FIG. 2(a-1) is bonded to the back surface 1A, the back surface 1B is ground (step (a)). Thereby, as shown in FIG. 2(a-2), a semiconductor wafer 1 with the semiconductor processing tape 3 bonded to the back surface 1A and thinned to a predetermined thickness can be obtained. The method of grinding the back surface 1B of the semiconductor wafer 1 is not particularly limited, and examples include a commonly applied back grind (BG) process or an etching process, and the BG process is preferred. The method and conditions in step (a) can be applied using ordinary methods and conditions.

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

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

[0076] In the manufacturing method of the present invention, next, as shown in FIG. 3(b), the semiconductor wafer 1 obtained in step (FC) is supported and fixed to the dicing tape 11 via the ring frame 12 (step (b)). The ring frame 12 and the dicing tape 11 used in step (b), and the method of further supporting and fixing can all be applied without particular limitation using the commonly used ones or methods. For example, as the dicing tape 11, a laminated tape of a base film 11A and a pressure-sensitive adhesive layer 11B can be used, and specifically, the tape described in Patent Document 2 can be used.

[0077] Next, as shown in FIG. 3(c), the surface protection tape 4 (base film 4A and pressure-sensitive adhesive layer 4B) of the cured tape 3 for semiconductor processing is peeled off from the water-soluble cured film 5C (step (c)). In this way, the surface protection tape 4 is removed, the water-soluble cured film 5C is exposed, and a semiconductor wafer 1 with the water-soluble cured film 5C bonded onto the circuit surface 1A is obtained. The surface protection tape 4 may be peeled off with a force equal to or greater than the peeling force between the water-soluble cured film 5C and the surface protection tape 4. When the pressure-sensitive adhesive layer 4B contains a radiation-curable pressure-sensitive adhesive, if radiation is irradiated from the surface protection tape 4 side to cure the pressure-sensitive adhesive layer 4B, the surface protection tape 4 will be more easily peeled off from the water-soluble cured film 5C. As a specific peeling method of the surface protection tape 4, ordinary methods can be applied.

[0078] In the manufacturing method of the present invention, next, as shown in FIG. 3(d-1), a laser is irradiated along the planned cutting region (street, 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)). Thus, as shown in FIG. 4(d-2), grooves 8 that enable the later-described plasma to be irradiated onto the semiconductor wafer 1 are provided in the water-soluble cured film 5C, and the water-soluble cured film 5C is fragmented. As a result, the planned cutting region of the semiconductor wafer 1 is exposed at the bottom of the groove 8. It is preferable that the width of the groove 8 to be formed is not more than the width of the street. As a method for cutting the water-soluble cured film 5C, for example, as shown in FIG. 3(d-1), there is a laser grooving method in which the laser light 7 output (emitted) from the laser light irradiation means 6 is irradiated onto the water-soluble film 5 while being relatively moved along the street for cutting. As the laser light irradiation means 6, for example, the device described in Patent Document 2 can be used. Even if the water-soluble cured film 5C of the hardening tape 3 for semiconductor processing is cut by laser irradiation, the fragmented water-soluble cured film 5C does not soften or melt, and grooves 8 having a predetermined dimension and shape can be formed. Moreover, the water-soluble cured film 5C is less likely to be deformed over time, and the groove width at the time of formation of the groove 8 can be maintained over a long period. As the groove formation conditions (laser irradiation conditions) in the laser grooving method, the conditions usually applied can be applied, but they are appropriately set in consideration of the composition, physical properties, etc. of the water-soluble cured film 5C. For example, as the conditions of the laser grooving method, it is possible to select from the conditions of 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 / second.

[0079] Next, as shown in FIG. 4(e), the exposed portion of the semiconductor wafer 1 is irradiated with plasma 10A from the side of the cut (fragmented) water-soluble cured film 5C for plasma treatment (step (e)). In this way, the semiconductor wafer 1 is etched and fragmented into individual chips 2. The method for fragmenting the semiconductor wafer 1 can be applied without particular limitation to the commonly applied plasma dicing method. In the manufacturing method of the present invention, as shown in FIG. 4(e), it is carried out under appropriate conditions using a plasma etching apparatus 10. As the plasma etching apparatus 10, for example, the apparatus described in Patent Document 2 can be used. The water-soluble cured film 5C of the cured tape 3 for semiconductor processing can maintain the groove 8 of a predetermined dimension and shape without the fragmented water-soluble cured film 5C softening or melting even when irradiated with plasma gas. As the conditions for plasma dicing, specifically, a fluorine-based gas such as SF6 can be introduced, and the etching rate can be selected from 0.5 to 10 μm / s. Also, the temperature, pressure, etc. can be appropriately set according to the type of plasma gas (generation conditions), etc. For example, the temperature can be 20 to 80°C, and the pressure can be 0.00001 to 0.05 MPa. The plasma treatment time can be appropriately determined in consideration of the output of the apparatus, the etching rate, etc., and can be, for example, 1 to 30 minutes. Note that the output of the plasma etching apparatus can be appropriately set and can be, for example, 1 to 300 W.

[0080] In the manufacturing method of the present invention, next, as shown in FIG. 4(f), the cut (fragmented) water-soluble cured film 5C is washed with water, preferably non-heated water (usually pure water) 9 (step (f)). In this way, the water-soluble cured film 5C is dissolved and removed to obtain the semiconductor chip 2. The method for cleaning and removing the water-soluble cured film is not particularly limited as long as it is a method of bringing water into contact with the water-soluble cured film. For example, while the assembly of the singulated semiconductor chips 2 is held on a spinner table in a state fixed to the ring frame 12, cleaning water composed of water 9 and air is ejected from a nozzle positioned above the center of the assembly of the semiconductor chips 2 while rotating the assembly of the semiconductor chips 2, and then, air is ejected from an air nozzle to dry the semiconductor chips 2. Since the water-soluble cured film of the tape for semiconductor processing in a preferred embodiment of the present invention exhibits sufficient solubility even in non-heated water as described above, non-heated water can be used as the water for cleaning the water-soluble cured film in this step, and this step can be carried out simply and energy-efficiently. The temperature of the cleaning water is not particularly limited and can be appropriately determined. For example, it can be less than 60°C, preferably 40°C or less. The lower limit value of the water temperature is not particularly limited, but usually can be 15°C, preferably 20°C. The water washing method is not particularly limited, and examples include a method of spraying water on the assembly of semiconductor chips, a method of applying water on the assembly of semiconductor chips, and a method of immersing the assembly of semiconductor chips in water. The water washing conditions are appropriately determined in consideration of the water solubility, thickness, etc. 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, as shown in FIG. 4(g), a pickup step (g) of picking up the assembly of the semiconductor chips 2 (the singulated semiconductor wafer 1) obtained in step (f) can also be performed. The pickup step (g) can be applied without particularly limiting the method usually applied. For example, as shown in FIG. 4(g), a method of picking up the semiconductor chips 2 by pushing them up with pins 15 and adsorbing them with a collet 16 together with the dicing tape 11 can be mentioned.

Example

[0082] Hereinafter, the present invention will be described more specifically 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 To 100 parts by mass of an acrylic polymer (manufactured by Shin-Nakamura Chemical Co., Ltd.) composed of 2-ethylhexyl acrylate, 1.5 parts by mass of Coronate L (product name, manufactured by Tosoh Corporation) shown below as a curing agent was dissolved in ethyl acetate to obtain an ethyl acetate solution of an adhesive. This solution was coated on a PET film (Therapeel WZ (trade name), thickness 25 μm, manufactured by Toray Industries, Inc.) that had been subjected to a release treatment so that the thickness after drying would be 30 μm, and then heat-dried. Thereafter, the adhesive layer formed on the PET film was laminated onto a base film (Nipolon Hard 4010 (trade name, manufactured by Tosoh Corporation)) made of polyethylene that had been extruded into a film with a thickness of 100 μm to produce a surface protection tape with a PET film.

[0084] Coronate L [Chemical formula]

[0085] (2) Preparation of water-soluble uncured film To 100 parts by mass of polyvinylpyrrolidone (PVP-K90: trade name) dissolved in 500 mL of water, 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 photo radical initiator, 70 parts by mass of polyethylene glycol (PEG400) as a plasticizer, and 1.9 parts by mass of Tinuvine 477 (product name) as an ultraviolet absorber were blended to obtain a water-soluble film solution (mask material solution). This solution was coated on a PET film (Therapeel WZ (trade name), thickness 25 μm, manufactured by Toray Industries, Inc.) that had been subjected to a release treatment so that the thickness after drying would be 10 μm, and then heat-dried. In this way, a water-soluble uncured film (water-soluble uncured film with a PET film) made of a curable resin composition was produced.

[0086] (3) Manufacture of uncured tape for semiconductor processing After that, after peeling off the PET film of the surface protection tape with the PET film obtained in the above (1), the water-soluble uncured film of the water-soluble uncured film with the PET film and the adhesive layer of the surface protection tape from which the PET film was peeled were bonded together to obtain an uncured tape for semiconductor processing. This uncured tape for semiconductor processing has a four-layer laminated structure of a base film / adhesive layer / water-soluble uncured film / PET film.

[0087] <Examples 2 to 11 and Comparative Examples 1 to 6> In the "Preparation of water-soluble uncured film" of Example 1, except that 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 the same manner as in Example 1, uncured tapes for semiconductor processing of Examples 2 to 11 and Comparative Examples 1 to 6 were each manufactured. In Tables 1 and 2, when the "content (parts by mass)" column of each component is blank, it means that the component is not contained.

[0088] <Comparative Example 7> In the "Preparation of water-soluble uncured film" of Example 1, an attempt was made to prepare a water-soluble uncured film in the same manner as in Example 1, except that isopropyl alcohol solvent was contained as a low molecular weight component in the water-soluble uncured film to be prepared at a content of 20% by mass, but the film shape could not be maintained. Therefore, the uncured tape for semiconductor processing of Comparative Example 7 could not be manufactured either.

[0089] The materials used in each example and comparative example are shown below. (Water-soluble polymer A) PVP: Polyvinylpyrrolidone, PVP-K90 (trade name), manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., weight average molecular weight by the above measurement method: 360,000 PVA: Polyvinyl alcohol, Poval 60-98 (trade name), saponification degree 98%, manufactured by Kuraray Co., Ltd., weight average molecular weight by the above measurement method: 400,000 (Monomer B) DMAPAA: N-[3-(Dimethylamino)propyl]acrylamide, manufactured by KJ Chemicals DEAA: Diethylacrylamide, manufactured by KJ Chemicals

[0090] (Photoinitiator) 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 PEG600: Polyethylene glycol, number average molecular weight 600, manufactured by Sanyo Chemical Industries (Other components) Tinuvin477: UV absorber, manufactured by BASF M5700: Trade name, 2-Hydroxy-3-phenoxypropyl acrylate, manufactured by Toagosei ACMO: Acryloylmorpholine, manufactured by KJ Chemical

[0091] The weight average molecular weight (Mw) of polyvinylpyrrolidone K90 and the number average molecular weight of the plasticizer were measured as the values (converted values of polyethylene glycol / polyethylene oxide (PEG / PEO)) when measured by GPC (Gel Permeation Chromatography) under the following conditions. GPC conditions: · Column: TSKgel SuperMultiporePW-M (6.0 mm I.D.×15 cm) · Eluent: 100 mmol / L NaNO3 · Flow rate: 0.6 mL / min · Detector: RI · Temperature: 25 °C · Injection volume: 20 μL · Sample preparation: The sample was prepared as a 3 mg / mL solution using pure water. The conversion from retention volume obtained by GPC measurement to molecular weight was performed using a calibration curve prepared with PEG / PEO for molecular weight calibration. For PEG / PEO, an Agilent polyethylene glycol / polyethylene oxide standard kit was used.

[0092] [Test] For each uncured tape for semiconductor processing obtained in the above Examples and Comparative Examples, tests were conducted on the following items. The results are summarized in Table 1 or Table 2.

[0093] <Test 1: Adhesion> The adhesion of each uncured tape for semiconductor processing prepared in each Example and Comparative Example to a semiconductor silicon wafer without surface coating (bare wafer) and a silicon wafer with benzocyclobutene (BCB) coated on the surface with a thickness of 1 μm (BCB-coated wafer) was evaluated by measuring the peel strength (N / 25 mm) by the following test. A water-soluble film solution prepared in the same manner as in the Examples and Comparative Examples was coated on a PET film subjected to an adhesion treatment, and dried by heating to prepare a test tape of PET film (thickness 38 μm) / water-soluble uncured film (thickness 10 μm). Here, the adhesion treatment was performed by corona treatment on the surface of the PET film at an intensity of 5 A. Next, after cutting the obtained test tape into a width of 25 mm, the water-soluble uncured film surface of the test tape was bonded to the mirror surface of the silicon wafer without surface coating and the coated surface of the silicon wafer with BCB coating at a temperature of 23°C, and then the water-soluble uncured film was cured. The bonding was performed by stacking the test tape on the silicon wafer and reciprocating a rubber roller with a load of 2 kg on the surface of the test tape three times. Also, the curing was carried out using a metal halide lamp with an intensity of 100 mW / cm 2 at an intensity of 1000 mJ / cm 2It was carried out by irradiating ultraviolet rays. For each wafer, the maximum peel strength between the water-soluble cured film and the wafer was measured using a Strograph VG1F (trade name, manufactured by Toyo Seiki Co., Ltd.) under the conditions of 23°C, a peel angle of 180°, and a peel rate of 300 mm / min, respectively, immediately after bonding (curing) and after leaving it in an environment of 23°C and 50% RH for 1 hour after bonding (curing). Conditions other than the above were in accordance with Japanese Industrial Standard (JIS) Z 0237:2009. For each wafer, the maximum peel strength (N / 25 mm) immediately after bonding and the maximum peel strength (N / 25 mm) after leaving it for 1 hour after bonding were evaluated based on the following evaluation criteria. In this test, the adhesion to a semiconductor silicon wafer without surface coating is referred to as "bare wafer adhesion", and the adhesion to a silicon wafer coated with benzocyclobutene (BCB) with a thickness of 1 μm on the surface is referred to as "BCB-coated wafer adhesion". In the "Adhesion" column of Table 1, the evaluation result applied according to the following evaluation criteria, the measured value α (N / 25 mm) of the maximum peel strength immediately after bonding, and the measured value β (N / 25 mm) of the maximum peel strength after leaving it for 1 hour after bonding were jointly recorded as "Evaluation result: α → β". - Evaluation criteria - ◎: The maximum peel strength immediately after bonding is 1.0 N / 25 mm or more 〇: The maximum peel strength immediately after bonding was less than 1.0 N / 25 mm, but the maximum peel strength after 1 hour of bonding was 1.0 N / 25 mm or more ×: The maximum peel strength after 1 hour of bonding is 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 method for manufacturing a semiconductor chip of the present invention, and the water-soluble cured film was also firmly adhered to the silicon wafer. In addition, 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 method for manufacturing a semiconductor chip of the present invention, and the water-soluble uncured film was also firmly adhered to the silicon wafer. On the other hand, since the semiconductor processing tapes of Comparative Examples 1 and 2 were inferior in adhesion and could not be used as semiconductor processing tapes, Tests 2 to 6 were not conducted.

[0094] <Test 2: Water washing removability> The PET film was peeled off from each semiconductor processing tape obtained in each Example and Comparative Example, and after the surface of the water-soluble uncured film was bonded to the mirror surface of the silicon wafer at a temperature of 23°C, the water-soluble uncured film was cured. The bonding was performed by overlapping the semiconductor processing tape on the silicon wafer and reciprocating a rubber roller with a load of 2 kg on the surface of the semiconductor processing tape 3 times. Further, the curing was carried out by irradiating ultraviolet rays of 1000 mJ / cm 2 using a metal halide lamp with an intensity of 100 mW / cm 2 . Next, the surface protection tape was peeled off from the water-soluble cured film. Then, the silicon wafer having the water-soluble cured film was set on 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 applied to the water-soluble cured film at a water volume of 100 mL / min for 2 minutes. After washing with water in this way, it was visually confirmed whether the water-soluble cured film remained on the silicon wafer, and evaluation was performed based on the following evaluation criteria. In addition, the "paste" in the evaluation criteria of this test refers to a lump formed by swelling the water-soluble cured film with water. - Evaluation criteria - ◎: The water-soluble cured film was dissolved and there was no paste residue. 〇: The paste residue of the water-soluble cured film was slight to an acceptable level as a semiconductor chip. ×: The water-soluble cured film swelled and the drain pipe (diameter 40 mm) of the spin coater was clogged.

[0095] <Test 3: Water washing removability after plasma treatment> The PET film was peeled off from each semiconductor processing tape obtained in each example and comparative example, and after the surface of the water-soluble uncured film was bonded to the mirror surface of the silicon wafer at a temperature of 23°C, the water-soluble uncured film was cured. The bonding was performed by stacking the semiconductor processing tape on the silicon wafer and reciprocating a rubber roller with a load of 2 kg on the surface of the semiconductor processing tape three times. Also, the curing was carried out by irradiating ultraviolet rays of 1000 mJ / cm 2 with a metal halide lamp having a strength of 100 mW / cm 2 . Next, after peeling the surface protection tape from the water-soluble cured film, the water-soluble cured film was plasma-treated under the following plasma treatment conditions. Then, 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 applied to the water-soluble cured film at a water volume of 100 mL / min for 2 minutes. After washing with water in this way, it was visually confirmed whether the water-soluble cured film remained on the silicon wafer, and evaluation was performed based on the following evaluation criteria. - Plasma treatment conditions - Plasma treatment apparatus: Model number NVC-103, manufactured by Nichiden Anzen Co., Ltd. Output of the treatment apparatus: 125 W Plasma gas: SF6 Treatment temperature: 60°C Treatment pressure: 0.0005 MPa Treatment time: 2 minutes - Evaluation criteria - ◎: The water-soluble cured film is dissolved and there is no adhesive residue. 〇: The adhesive residue of the water-soluble cured film is slightly within an acceptable level as a semiconductor chip. ×: The water-soluble cured film swells and the drain pipe (diameter 40 mm) of the spin coater is clogged.

[0096] <Test 4: Heat resistance 1 (Plasma heat resistance, apparatus contamination suppression)> The water-soluble uncured films of each example and comparative example were fixed on the mirror surface of a silicon wafer fixed on a chuck table in the same manner as in Test 5 below, and then, after being bonded, irradiated with ultraviolet rays of 1000 mJ / cm 2 using a metal halide lamp with an intensity of 100 mW / cm 2 to cure the water-soluble uncured films. Next, a surface protection tape was peeled off from the water-soluble cured film to expose the water-soluble cured film, and plasma treatment was performed 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 body of a silicon wafer and a water-soluble cured film was produced. At the end of this laminated test body (silicon wafer), the amount of deformation of the water-soluble cured resin composition forming the water-soluble cured film was confirmed with a microscope. The amount of deformation was based on the target position where the water-soluble cured film was cut by laser grooving, and the actual edge position was observed with a microscope. Further, without removing the above laminated test body 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. The heat resistance 1 test is a test for evaluating the deformation prevention characteristics of the water-soluble film and the characteristics of being difficult to contaminate the apparatus after the implementation of the plasma dicing process. Specifically, it is a test for evaluating the characteristics that the water-soluble film is not softened or melted by the heat of plasma gas irradiation, protects the parts other than the plasma gas irradiation target by the heat of plasma gas irradiation, and is difficult to contaminate various apparatuses during the handling of the semiconductor processing tape. - Evaluation Criteria - ◎: The amount of deformation is 100 μm or less, and there is no contamination on the chuck table 〇: The amount of deformation is less than 100 μm and 100 μm or less, and there is no contamination on the chuck table and ×: The amount of deformation is 1000 μm or more, or the water-soluble cured resin composition flows from the silicon wafer and contaminates the end of the chuck table

[0097] <Test 5: Heat Resistance 2 (Laser Heat Resistance)> From each semiconductor processing tape obtained in each example and comparative example, the PET film was peeled off, and after the surface of the water-soluble uncured film was bonded to the mirror surface of the silicon wafer at a temperature of 23°C, the water-soluble uncured film was cured. The bonding was performed by stacking the semiconductor processing tape on the silicon wafer and reciprocating a rubber roller with a load of 2 kg three times on the surface of the semiconductor processing tape. Also, the curing was carried out by irradiating ultraviolet rays of 1000 mJ / cm 2 using a metal halide lamp with an intensity of 2 . Next, the surface protection tape was peeled off from the water-soluble cured film, and the exposed water-soluble cured film was cut using a laser dicing machine 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. After cutting the water-soluble cured film, the wafer portion (the exposed portion of the wafer) was immediately observed with a microscope, and for the formed grooves, the groove width at a position 1 μm deep from the surface layer at intervals of 100 μm in the groove length was actually measured at 10 points. The average value of the 10 actually measured widths was obtained and evaluated based on the following evaluation criteria. This test is a test for evaluating the deformation prevention characteristics of the water-soluble film immediately after the implementation of the laser grooving process. Specifically, it is a test for evaluating a higher-level characteristic that the water-soluble film does not soften or melt due to the heat of laser irradiation, maintains the formed groove width, and the water-soluble film does not flow down into the groove (the exposed portion of the wafer). - Evaluation Criteria - ○: The actually measured width of the formed groove is within the range of 80 - 120% with respect to the groove formation width of 10 μm △: The actually measured width of the formed groove is within the range of 60 - 140% with respect to the groove formation width of 10 μm (However, excluding the range of 90 - 110%) ×: The actually measured width of the formed groove is less than 60% or exceeds 140% with respect to the groove formation width of 10 μm

[0098] ​ <Test 6: Heat Resistance 3 (Heat Resistance over Time)> In the above Test 5, after the laser grooving process was carried out and left standing in an environment of 23°C and 50% RH in the atmosphere for 7 days, the groove width (average value) of the grooves formed in each water-soluble cured film was measured. Except for this, in the same manner as in Test 5, the deformation prevention characteristics of the water-soluble film 7 days after the laser grooving process was carried out were evaluated. This test is a test for evaluating the deformation prevention characteristics of the water-soluble film 7 days after the laser grooving process. Specifically, it is a test for evaluating a higher-level characteristic that the formed groove width is maintained even after 7 days without the water-soluble film being softened or melted by the heat of laser irradiation, and the water-soluble film does not flow down into the grooves (the exposed part of the wafer). Note that in Example 1, since the result of Test 5 was an "×" evaluation, Test 6 of the present invention was not conducted.

[0099] <Test 7: Gel Fraction of Water-Soluble Cured Film> In the same manner as the preparation of the water-soluble uncured films of each example and comparative example, a water-soluble uncured film with a PET film was prepared. This water-soluble uncured film with a PET film was cured. The curing was carried out by irradiating ultraviolet rays of 1000 mJ / cm 2 using a metal halide lamp with an intensity of 100 mW / cm 2 . Next, the obtained water-soluble cured film was peeled off from the PET film. Then, about 1 g of the water-soluble cured film was put into 100 g of pure water placed under the environmental conditions of 30°C and 50% RH and stirred at 300 rpm for 10 minutes. The mass of the components remaining on the wire mesh was determined through a 100-mesh wire mesh, and the ratio to the original mass was determined to obtain the gel fraction (%).

[0100]

Table 1

[0101]

Table 2

[0102] The following can be understood from the above results. Even when the water-soluble polymer A and furthermore a plasticizer are contained, the uncured tapes for semiconductor processing of Comparative Examples 1 to 4 each having a water-soluble uncured film not containing monomer B do not show sufficient adhesion to the semiconductor wafer. Moreover, the uncured tapes for semiconductor processing of Comparative Example 4 were also inferior in plasma heat resistance. Further, the uncured tapes for semiconductor processing of Comparative Examples 5 and 6 each having a water-soluble uncured film in which an acrylate monomer was used in combination with the water-soluble polymer A instead of monomer B were inferior in water-washing removability or adhesion. On the other hand, the uncured tape for semiconductor processing of the example provided with the water-soluble uncured film containing the water-soluble polymer A and the monomer B exhibits sufficient adhesiveness to the wafer having a hydrophilic surface and the wafer having a hydrophobic surface, and high water-wash removability that enables removal by washing with non-heated water even after curing. Moreover, these tapes for semiconductor processing also exhibit high heat resistance. Therefore, the uncured tape for semiconductor processing of the example exhibits high water-wash removability that enables removal by washing with non-heated water even after curing while achieving both heat resistance after curing and wafer adhesiveness in the uncured state. Thus, the tape for semiconductor processing of each example corresponding to the tape for semiconductor processing having the water-soluble film of the present invention can protect the back surface of the semiconductor wafer in the backgrinding process, and can perform the plasma dicing process simply while ensuring the degree of freedom in process design, and is suitably used for a method for manufacturing a semiconductor chip including the plasma dicing process. Among them, the tapes for semiconductor processing of Examples 2 to 11 corresponding to the tape for semiconductor processing having the water-soluble film of a preferred embodiment of the present invention can protect the back surface of the semiconductor wafer in the backgrinding process, and can perform the laser grooving process and the plasma dicing process simply while ensuring the degree of freedom in process design, and are suitably used for a method for manufacturing a semiconductor chip including the laser grooving process and the plasma dicing process. It can be understood that by using these tapes for semiconductor processing in a method for manufacturing a semiconductor chip including a plasma dicing process, preferably further including a laser grooving process, it is possible to simply manufacture a semiconductor chip having high dimensional accuracy without chipping while ensuring the degree of freedom in process design.

Explanation of Symbols

[0103] 1 Semiconductor wafer 1A Back surface 1B Rear surface 2 Semiconductor chip 3 Tape for semiconductor processing 4 Surface protection tape 4A Base film 4B Adhesive layer 5 Water-soluble uncured film 5C Water-soluble hardening film 5U Ultraviolet ray 6 Laser light irradiation means 7 Laser light 8 Groove 9 Water 10 Plasma etching apparatus 10A Plasma 11 Dicing tape 11A Base film 11B Adhesive layer 12 Ring frame 15 Pin 16 Collet

Claims

1. A 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 no ring structure containing amide nitrogen, with a molecular weight of 200 or less and the content of components other than the monomer B being 10% by mass or less, and having a gel fraction of 10% or less after being immersed in water at 30°C for 10 minutes when cured.

2. The water-soluble film according to Claim 1, wherein the monomer B is represented by the following formula (B1) or formula (B2). 【Chemical 1】 In formula (B1), R １ represents a hydrogen atom or an alkyl group, and R ２ and R ３ represent an alkyl group or an aryl group. However, R ２ and R ３ do not combine with 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 represent an alkyl group or an aryl group. However, R ５ and R ６ do not combine with each other to form a ring structure containing N.

3. The water-soluble film according to Claim 1, wherein the content of the monomer B relative to 100 parts by mass of the water-soluble polymer A is 100 to 300 parts by mass.

4. The water-soluble film according to Claim 1 for plasma treatment and / or laser treatment.

5. A semiconductor processing tape obtained by laminating the water-soluble film according to any one of Claims 1 to 4 and a surface protection tape for protecting the back surface of a semiconductor wafer.

6. A step (a) of grinding the back surface of the semiconductor wafer, wherein the water-soluble film in the semiconductor processing tape according to Claim 5 is bonded to the back surface of the semiconductor wafer without heating; a step (FC) of irradiating the water-soluble film in the semiconductor processing tape with radiation from the surface protection tape side to cure 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 in the semiconductor processing tape from the cured water-soluble film to expose the water-soluble film; a step (d) of irradiating the cured water-soluble film with a laser along the planned cutting region of the semiconductor wafer to cut and provide a groove; a step (e) of subjecting the semiconductor wafer to plasma treatment from the water-soluble film side cut in step (d) to singulate the semiconductor wafer; a step (f) of washing the cut water-soluble film with water to dissolve and remove it; and having, a method for manufacturing semiconductor chips.

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