Method for manufacturing an electronic device

Abstract

To provide a manufacturing method of an electronic device apparatus which is improved in processing precision in grinding and individualizing a workpiece and capable of suppressing an adhesive left in the individualized workpiece after the individualization.SOLUTION: The present invention relates to a manufacturing method of an electronic device apparatus including a predetermined dividing line forming step (A), a sheet sticking step (B) and a grinding and individualizing step (C) and further including a step (D) and a step (E) between the sheet sticking step (B) and the grinding and individualizing step (C). The step (D) is a step of irradiating an energy ray curable adhesive layer of a protective sheet for workpiece processing stuck to a workpiece with energy rays, and the step (E) is a step of grinding a substrate surface of the protective sheet for workpiece processing stuck to the workpiece.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing an electronic device. [Background technology]

[0002] 2. Description of the Related Art As information terminal equipment is rapidly becoming thinner, smaller and more multifunctional, electronic devices such as semiconductor devices mounted on these equipment are also being required to be thinner and more dense. A method for thinning electronic devices has been to grind the backside of a workpiece used in the electronic device. Backside grinding of the workpiece is performed by attaching a workpiece processing protection sheet, such as a backgrinding tape, to the surface of the workpiece to protect the surface of the workpiece. After backside grinding, the workpiece processing protection sheet is peeled off and removed from the surface of the workpiece.

[0003] In recent years, blade-tip dicing and stealth-tip dicing have been put into practical use as grinding and singulation methods for thinning a workpiece while minimizing damage to the individual pieces after singulation. The blade-tip dicing method involves forming grooves of a predetermined depth on the surface of the workpiece using a dicing blade or the like, and then grinding the workpiece from the backside down to the grooves to singulate the workpiece into individual pieces (see, for example, Patent Document 1). The stealth-tip dicing method involves forming modified regions inside the workpiece by irradiating it with laser light, then grinding the workpiece from the backside and splitting the modified regions as starting points to singulate the workpiece into individual pieces (see, for example, Patent Document 2). These methods also use a protective sheet for workpiece processing to protect the surface of the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-193417 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-49904 Summary of the Invention [Problem to be solved by the invention]

[0005] In the methods disclosed in Patent Documents 1 and 2, by adhering or fixing a protective sheet for workpiece processing to the surface of a workpiece, it is possible to suppress displacement of the individual workpieces due to vibration during backgrinding of the workpiece. However, because the protective sheet for workpiece processing is flexible, the surface of the protective sheet for workpiece processing becomes uneven due to the uneven shape of the workpiece surface. This causes a problem of unstable grinding surface during backgrinding of the workpiece, reducing the processing accuracy of the workpiece. In addition, due to vibration during backgrinding of the workpiece, the protective sheet for workpiece processing can get caught in grooves or modified areas formed in the workpiece, causing adhesive residue.

[0006] The present invention has been made in consideration of the above-described situation, and aims to provide a method for manufacturing an electronic device that has excellent processing accuracy when grinding and singulating a workpiece, and can suppress glue residue on the singulated workpieces after singulation. [Means for solving the problem]

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the problems can be solved by the following invention.

[0008] That is, the present invention relates to the following: [1] A process (A) for forming a modified region inside the workpiece from the front or back surface of the workpiece, or a process (B) for forming a groove on the surface of the workpiece; A sheet attaching step (B) is performed before the step a or after the step b, in which a protective sheet for workpiece processing having an energy ray curable adhesive layer on a substrate is attached to the surface of the workpiece with the energy ray curable adhesive layer as an attachment surface; A grinding and singulation step (C) of grinding the back surface of the workpiece to singulate the workpiece into a plurality of workpiece singulations starting from the modified regions or grooves, The method for manufacturing an electronic device further includes the following steps (D) and (E) between the sheet attaching step (B) and the grinding and singulating step (C): Step (D): A step of irradiating the energy ray-curable adhesive layer of the protection sheet for workpiece processing attached to the workpiece with energy rays. Step (E): A step of grinding the substrate surface of the workpiece processing protection sheet attached to the workpiece [2] The method for producing an electronic device according to [1] above, wherein the steps (D) and (E) are carried out in this order. [3] The method for producing an electronic device according to the above [1] or [2], wherein the step (A) of forming lines to be divided is step a. [4] The method for producing an electronic device according to the above [1] or [2], wherein the step (A) of forming lines to be divided is step b. [5] The method for producing an electronic device according to [3] above, wherein the steps (D) and (E) are carried out in this order before the step a. [6] The method for manufacturing an electronic device according to any one of the above [1] to [5], wherein the thickness of the workpieces after grinding in the grinding and singulating step (C) is less than 50 μm. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a manufacturing method for an electronic device that has excellent processing accuracy when grinding and dividing a workpiece, and that can suppress adhesive residue on the divided workpieces after division. DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification, the lower and upper limits of preferred numerical ranges described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0011] In this specification, the term "energy rays" refers to electromagnetic waves or charged particle beams that have an energy quantum, and examples thereof include ultraviolet rays, radioactive rays, and electron beams. Ultraviolet rays can be irradiated using, for example, an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, or the like as an ultraviolet light source. Electron beams can be irradiated using those generated by an electron beam accelerator, or the like. In this specification, the term "energy ray curable" means the property of being cured by irradiation with energy rays.

[0012] In this specification, the term "workpiece" refers to a plate-shaped body to which the workpiece processing protective sheet of this embodiment is attached and then singulated. Examples of workpieces include circular wafers (including those with orientation flats), rectangular panel-level packages, and strips (rectangular substrates) sealed with molded resin. Among these, wafers are preferred because they facilitate the attainment of the effects of the present invention. Examples of wafers include semiconductor wafers such as silicon wafers, gallium arsenide wafers, silicon carbide wafers, gallium nitride wafers, and indium phosphide wafers, as well as insulator wafers such as glass wafers, lithium tantalate wafers, and lithium niobate wafers. They may also be reconstructed wafers made of resin and semiconductors used in the manufacture of fan-out packages, etc. Because the effects of the present invention are readily attainable, semiconductor wafers or insulator wafers are preferred. Semiconductor wafers are more preferred, and silicon wafers are particularly preferred. In this specification, the term "single workpiece" refers to a workpiece divided into individual circuits. For example, if the workpiece is a wafer, the single workpiece is a chip, and if the workpiece is a panel level package or a strip (rectangular substrate) sealed with molded resin, the single workpiece is a semiconductor package.

[0013] In this specification, the "front surface" of a workpiece refers to the surface on which a circuit is formed, and the "back surface" refers to the surface on which no circuit is formed.

[0014] [Method of manufacturing an electronic device] The manufacturing method for an electronic device apparatus of this embodiment includes a division line forming step (A), which is a step a of forming a modified region inside the workpiece from the front or back surface of the workpiece, or a step b of forming a groove on the surface of the workpiece; a sheet attaching step (B) of attaching a workpiece processing protective sheet having an energy ray curable adhesive layer on a substrate to the front surface of the workpiece, with the energy ray curable adhesive layer serving as an attachment surface, before step a or after step b; and a grinding and singulation step (C) of grinding the back surface of the workpiece to singulate the workpiece into a plurality of workpiece pieces starting from the modified region or groove, and further includes the following steps (D) and (E) between the sheet attaching step (B) and the grinding and singulation step (C). Step (D): A step of irradiating the energy ray-curable adhesive layer of the protection sheet for workpiece processing attached to the workpiece with energy rays. Step (E): A step of grinding the substrate surface of the workpiece processing protection sheet attached to the workpiece

[0015] In this embodiment, the term "electronic device" refers to any device that can function by utilizing semiconductor characteristics. Examples include workpieces, individual workpieces, electronic components including the individual workpieces, and electronic devices including the electronic components. Among these, the manufacturing method of this embodiment is suitable for processing workpieces.

[0016] According to the method for manufacturing an electronic device of this embodiment, between the sheet attachment step (B) and the grinding and singulation step (C), a step (D) of irradiating the energy ray-curable adhesive layer of the workpiece processing protective sheet attached to the workpiece with energy rays and a step (E) of grinding the substrate surface of the workpiece processing protective sheet attached to the workpiece are performed. Therefore, before the grinding and singulation step (C), the substrate surface of the workpiece processing protective sheet is flattened and the energy ray-curable adhesive layer of the workpiece processing protective sheet is cured. This stabilizes the grinding surface during back grinding of the workpiece, thereby improving the processing accuracy when grinding and singulating the workpiece. Furthermore, adhesive residue on the individual workpieces after singulation can be reduced.

[0017] The surface of the workpiece usually has circuits such as wiring, capacitors, diodes, transistors, etc. These circuits can be formed by conventionally known methods such as etching and lift-off. The thickness of the workpiece before grinding is not particularly limited, but is usually 500 to 1,000 μm. Each step of the method for manufacturing an electronic device according to this embodiment will be described in detail below.

[0018] [Division line formation process (A)] The dividing line forming step (A) is a step a of forming a modified region inside the workpiece from the front or back surface of the workpiece, or a step b of forming a groove on the surface of the workpiece. The method for manufacturing an electronic device including the above step a is a process equivalent to a stealth tip dicing method, and the method for manufacturing an electronic device including the above step b is a process equivalent to a blade tip dicing method.

[0019] Step a is a step of forming a modified region inside the workpiece from the front or back surface thereof, and is carried out after a workpiece processing protection sheet is attached to the front surface of the workpiece. In step a, a modified region is formed inside the workpiece by irradiating a laser focused on the inside of the workpiece. The modified region is a brittle portion of the workpiece, which is destroyed when the workpiece is thinned by back grinding or when grinding force is applied, and becomes a region that becomes the starting point for dividing the workpiece into individual workpieces. Therefore, the modified region is formed along the dividing line when the workpiece is divided into individual workpieces. The laser irradiation may be performed from the front side or the back side of the workpiece through the protective sheet for workpiece processing.

[0020] Step b is a step of forming grooves on the surface of the workpiece, and is carried out before the workpiece processing protection sheet is attached to the surface of the workpiece. The grooves formed on the surface of the workpiece in process b are shallower than the thickness of the workpiece. After process b, the backside of the workpiece is ground down to the grooves formed in process b, and the workpiece is divided into a plurality of individual workpieces. Therefore, in process b, the grooves are formed along the dividing lines when the workpiece is divided into individual workpieces. The grooves can be formed by dicing using a conventionally known wafer dicing device or the like.

[0021] [Sheet attachment process (B)] The sheet attachment step (B) is a step of attaching a workpiece processing protection sheet having an energy ray-curable adhesive layer on a substrate to the surface of the workpiece, with the energy ray-curable adhesive layer serving as the attachment surface, before the step a or after the step b. The method for attaching the workpiece processing protection sheet is not particularly limited, and any conventionally known method using, for example, a laminator or the like can be applied.

[0022] The workpiece processing protective sheet is attached to the surface of the workpiece and is used to grind and singulate the workpiece while protecting the surface. After the workpiece is singulated into individual workpieces, the workpiece processing protective sheet is peeled off and removed from the individual workpieces. The protection sheet for workpiece processing has a substrate and an energy ray-curable adhesive layer formed on the substrate.

[0023] <Base material> Examples of the substrate include various resin films. Examples of resins constituting the resin film include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins such as polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymers, and norbornene resins; ethylene copolymers such as ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylic acid ester copolymers; polyvinyl chlorides such as polyvinyl chloride and vinyl chloride copolymers; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and wholly aromatic polyesters; polyurethanes, polyimides, polyamides, polycarbonates, fluororesins, polyacetals, modified polyphenylene oxides, polyphenylene sulfides, polysulfones, polyether ketones, and acrylic polymers. The substrate may be a single-layer film made of one or more resins selected from these resins, or a laminate film made of two or more of these resin films, or a modified film such as a crosslinked film or ionomer film of the above resin. Among these resin films, the substrate is preferably one or more selected from polyester film, polyamide film, polyimide film, polyurethane acrylate film and biaxially oriented polypropylene film, more preferably polyester film, and even more preferably polyethylene terephthalate film.

[0024] The Young's modulus of the substrate is not particularly limited, but is preferably 50 MPa or more, more preferably 1,000 to 30,000 MPa, and even more preferably 2,500 to 6,000 MPa. When the Young's modulus of the substrate is equal to or greater than the lower limit, vibration during processing of the workpiece is suppressed, and processing accuracy tends to improve. When the Young's modulus of the substrate is equal to or less than the upper limit, workability during application to the surface of the workpiece and workability during removal from the workpiece tend to improve. The Young's modulus of the substrate can be measured in accordance with JIS K 7127:1999 at a test speed of 200 mm / min.

[0025] The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 25 to 100 μm, and even more preferably 30 to 70 μm. When the thickness of the substrate is equal to or greater than the lower limit, the substrate tends to have sufficient strength to function as a support for the workpiece processing protection sheet, whereas when the thickness of the substrate is equal to or less than the upper limit, the substrate tends to have adequate flexibility and improve handleability. The "thickness of the substrate" means the thickness of the entire substrate, and when the substrate is made up of multiple layers, it means the total thickness of all layers constituting the substrate.

[0026] The substrate may contain a plasticizer, a lubricant, an infrared absorber, an ultraviolet absorber, a filler, a colorant, an antistatic agent, an antioxidant, a catalyst, and the like, as long as the effects of the present invention are not impaired. The substrate may be transparent or opaque and may be colored or vapor-deposited as desired. From the viewpoint of improving adhesion to other layers, the substrate may be subjected to a surface treatment such as corona treatment on at least one side, or may be provided with a coating layer for the purpose of improving adhesion.

[0027] <Energy ray curable adhesive layer> The energy ray-curable adhesive layer (hereinafter simply referred to as adhesive layer) is a layer to be attached to the surface of a workpiece, and is formed from an energy ray-curable adhesive. By being formed from an energy ray-curable adhesive, the adhesive layer can provide sufficient adhesion to protect the workpiece surface well before energy ray curing, and has a reduced peel force after energy ray curing, making it easy to peel from the workpiece.

[0028] Examples of the energy ray-curable adhesive include the following X-type adhesive composition, Y-type adhesive composition, and XY-type adhesive composition. X-type adhesive composition: an energy ray-curable adhesive composition containing a non-energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin I") and an energy ray-curable compound other than the adhesive resin. Y-type adhesive composition: An energy ray-curable adhesive composition containing an energy ray-curable adhesive resin (hereinafter also referred to as "adhesive resin II") in which an unsaturated group has been introduced into the side chain of a non-energy ray-curable adhesive resin, and not containing any energy ray-curable compound other than the adhesive resin. XY-type adhesive composition: an energy ray-curable adhesive composition containing the above energy ray-curable adhesive resin II and an energy ray-curable compound other than the adhesive resin. Among these, the energy ray-curable adhesive is preferably an XY-type adhesive composition, which tends to have sufficient adhesiveness before curing while being able to sufficiently reduce the peel force from the workpiece after curing.

[0029] Next, each component constituting the pressure-sensitive adhesive layer will be described in more detail. In the following description, the term "adhesive resin" is used to refer to either or both of adhesive resin I and adhesive resin II. In addition, in the following description, when simply referring to an "adhesive composition," this concept includes an X-type adhesive composition, a Y-type adhesive composition, and an XY-type adhesive composition.

[0030] Examples of adhesive resins include acrylic resins, urethane resins, rubber resins, silicone resins, etc. Among these, acrylic resins are preferred.

[0031] (acrylic resin) The acrylic resin preferably contains a structural unit derived from an alkyl(meth)acrylate. Examples of alkyl(meth)acrylates include alkyl(meth)acrylates in which the alkyl group has 1 to 20 carbon atoms. The alkyl group contained in the alkyl(meth)acrylate may be linear or branched.

[0032] From the viewpoint of further improving the adhesive strength of the adhesive layer, the acrylic resin preferably contains a structural unit derived from an alkyl(meth)acrylate in which the alkyl group has 4 or more carbon atoms. The structural unit derived from alkyl (meth)acrylate in which the alkyl group contains 4 or more carbon atoms contained in the acrylic resin may be of one type alone or of two or more types. The alkyl group of the alkyl (meth)acrylate having 4 or more carbon atoms preferably has 4 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, and even more preferably 4 to 6 carbon atoms. Examples of alkyl(meth)acrylates in which the alkyl group has 4 or more carbon atoms include butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, undecyl(meth)acrylate, dodecyl(meth)acrylate, etc. Among these, butyl(meth)acrylate is preferred, and butyl acrylate is more preferred. When the acrylic resin contains a structural unit derived from an alkyl (meth)acrylate in which the alkyl group has 4 or more carbon atoms, the content thereof in the acrylic resin is preferably 30 to 90 mass %, more preferably 40 to 80 mass %, and even more preferably 45 to 60 mass %, from the viewpoint of further improving the adhesive strength of the adhesive layer.

[0033] From the viewpoint of improving the elastic modulus and adhesive properties of the adhesive layer, it is preferable that the acrylic resin contains a structural unit derived from an alkyl (meth)acrylate in which the alkyl group has 4 or more carbon atoms, as well as a structural unit derived from an alkyl (meth)acrylate in which the alkyl group has 1 to 3 carbon atoms. The structural unit derived from alkyl (meth)acrylate in which the alkyl group contains 1 to 3 carbon atoms contained in the acrylic resin may be of one type alone or of two or more types. Examples of alkyl(meth)acrylates in which the alkyl group has 1 to 3 carbon atoms include methyl(meth)acrylate, ethyl(meth)acrylate, isopropyl(meth)acrylate, n-propyl(meth)acrylate, etc. Among these, methyl(meth)acrylate and ethyl(meth)acrylate are preferred, methyl(meth)acrylate is more preferred, and methyl methacrylate is even more preferred. When the acrylic resin contains an alkyl (meth)acrylate in which the alkyl group has 1 to 3 carbon atoms, the content thereof in the acrylic resin is preferably 1 to 35 mass %, more preferably 5 to 30 mass %, and even more preferably 15 to 25 mass %.

[0034] The acrylic resin preferably further contains a structural unit derived from a functional group-containing monomer. When the acrylic resin contains a constituent unit derived from a functional group-containing monomer, it is possible to introduce a functional group that acts as a crosslinking origin that reacts with a crosslinking agent, or a functional group that reacts with an unsaturated group-containing compound to introduce an unsaturated group into the side chain of the acrylic resin. The structural unit derived from the functional group-containing monomer contained in the acrylic resin may be of one type alone or two or more types.

[0035] Examples of functional group-containing monomers include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, etc. Among these, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferred, and hydroxyl group-containing monomers are more preferred. Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol; and the like. Examples of carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids and anhydrides thereof such as fumaric acid, itaconic acid, maleic acid and citraconic acid; and 2-carboxyethyl methacrylate.

[0036] When the acrylic resin contains a structural unit derived from a functional group-containing monomer, the content thereof is not particularly limited, but is preferably 5 to 45 mass %, more preferably 15 to 40 mass %, and even more preferably 25 to 35 mass % in the acrylic resin.

[0037] In addition to the above-mentioned structural units, the acrylic resin may contain structural units derived from other monomers copolymerizable with the acrylic monomer. The structural units derived from other monomers contained in the acrylic resin may be of one type alone or two or more types. Examples of other monomers include styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0038] The acrylic resin may further contain an energy ray-polymerizable unsaturated group introduced therein in order to impart energy ray-curability. The unsaturated group can be introduced, for example, by reacting a functional group of an acrylic resin containing a constituent unit derived from a functional group-containing monomer with a reactive substituent reactive with the functional group and a reactive substituent of a compound having an unsaturated group (hereinafter also referred to as an "unsaturated group-containing compound"). One type of unsaturated group-containing compound may be used alone, or two or more types may be used in combination. Examples of the unsaturated group contained in the unsaturated group-containing compound include a (meth)acryloyl group, a vinyl group, an allyl group, etc. Among these, a (meth)acryloyl group is preferred. Examples of reactive substituents that the unsaturated group-containing compound has include an isocyanate group and a glycidyl group. Examples of the unsaturated group-containing compound include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0039] When an acrylic resin containing a structural unit derived from a functional group-containing monomer is reacted with an unsaturated group-containing compound, the ratio of functional groups that react with the unsaturated group-containing compound to the total number of functional groups in the acrylic resin is not particularly limited, but is preferably 60 to 98 mol %, more preferably 70 to 95 mol %, and even more preferably 80 to 93 mol %. When the ratio of functional groups that react with the unsaturated group-containing compound is within the above range, sufficient energy ray curability can be imparted to the acrylic resin, and the functional groups that have not reacted with the unsaturated group-containing compound can be reacted with a crosslinking agent to crosslink the acrylic resin.

[0040] The mass average molecular weight (Mw) of the acrylic resin is not particularly limited, but is preferably 300,000 to 1,500,000, more preferably 350,000 to 1,000,000, and even more preferably 400,000 to 600,000. When the mass average molecular weight (Mw) of the acrylic resin is within the above range, the adhesive strength and cohesive strength of the pressure-sensitive adhesive layer tend to be better.

[0041] (energy ray curable compound) The energy ray-curable compound contained in the X-type or XY-type pressure-sensitive adhesive composition is preferably a monomer or oligomer having an unsaturated group in the molecule and curable by energy ray irradiation. Examples of the energy ray-curable compound include polyvalent (meth)acrylate monomers such as trimethylolpropane tri(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol (meth)acrylate; and oligomers such as urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and epoxy (meth)acrylate. Among these, urethane (meth)acrylate oligomers are preferred from the viewpoints that they have a relatively high molecular weight and are less likely to reduce the elastic modulus of the pressure-sensitive adhesive layer.

[0042] The molecular weight of the energy ray-curable compound is not particularly limited, but is preferably 100 to 12,000, more preferably 200 to 10,000, even more preferably 400 to 8,000, and still more preferably 600 to 6,000. When the energy ray-curable compound is an oligomer, the above molecular weight means the mass average molecular weight (Mw).

[0043] The content of the energy ray-curable compound in the X-type pressure-sensitive adhesive composition is not particularly limited, but is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and even more preferably 60 to 90 parts by mass relative to 100 parts by mass of the pressure-sensitive adhesive resin. When the content of the energy ray-curable compound in the X-type pressure-sensitive adhesive composition is within the above range, the balance between the adhesive strength before energy ray irradiation and the releasability after energy ray irradiation tends to be good.

[0044] The content of the energy ray-curable compound in the XY-type pressure-sensitive adhesive composition is not particularly limited, but is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 3 to 15 parts by mass relative to 100 parts by mass of the pressure-sensitive adhesive resin. When the content of the energy ray-curable compound in the XY-type pressure-sensitive adhesive composition is within the above range, the balance between the adhesive strength before energy ray irradiation and the peelability after energy ray irradiation tends to be good. Note that, since the adhesive resin in the XY-type pressure-sensitive adhesive composition is energy ray-curable, even if the content of the energy ray-curable compound is small, the peel strength after energy ray irradiation tends to be sufficiently reduced.

[0045] (Crosslinking agent) The pressure-sensitive adhesive composition preferably further contains a crosslinking agent. The crosslinking agent crosslinks the adhesive resins together by reacting with the functional group derived from the functional group-containing monomer contained in the adhesive resin, for example. The crosslinking agent may be used alone or in combination of two or more kinds.

[0046] Examples of crosslinking agents include isocyanate-based crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, and adducts thereof; epoxy-based crosslinking agents such as ethylene glycol glycidyl ether; aziridine-based crosslinking agents such as hexa[1-(2-methyl)-aziridinyl]triphosphatriazine; chelate-based crosslinking agents such as aluminum chelate; etc. Among these, isocyanate-based crosslinking agents are preferred from the viewpoints of increasing cohesive strength and further improving adhesive strength, and from the viewpoints of ease of availability.

[0047] When the pressure-sensitive adhesive composition contains a crosslinking agent, the content thereof is not particularly limited, but from the viewpoint of allowing the crosslinking reaction to proceed appropriately, it is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass relative to 100 parts by mass of the pressure-sensitive adhesive resin.

[0048] (Photopolymerization initiator) The pressure-sensitive adhesive composition preferably further contains a photopolymerization initiator. When the energy ray-curable pressure-sensitive adhesive contains a photopolymerization initiator, the curing reaction of the energy ray-curable pressure-sensitive adhesive tends to proceed sufficiently even with relatively low-energy energy rays such as ultraviolet rays. The photopolymerization initiator may be used alone or in combination of two or more kinds.

[0049] Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and further photosensitizers such as amines and quinones. More specific examples include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0050] When the energy ray-curable adhesive contains a photopolymerization initiator, the content thereof is not particularly limited, but from the viewpoint of allowing the energy ray curing reaction to proceed uniformly and sufficiently, it is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass relative to 100 parts by mass of the adhesive resin.

[0051] (Other additives) The PSA composition may contain other additives within the range that does not impair the effects of the present invention, such as antistatic agents, antioxidants, softeners, fillers, rust inhibitors, pigments, dyes, etc. The content of other additives in the pressure-sensitive adhesive composition is not particularly limited, but is preferably 0 to 6 mass%, more preferably 0.01 to 5 mass%, and even more preferably 0.1 to 3 mass%, relative to the total amount (100 mass%) of the active ingredients in the pressure-sensitive adhesive composition. In this embodiment, the active ingredient of the pressure-sensitive adhesive composition means the components contained in the pressure-sensitive adhesive composition excluding components such as organic solvents that are removed during the process of forming the pressure-sensitive adhesive layer.

[0052] (organic solvent) The pressure-sensitive adhesive composition may be diluted with an organic solvent to form a solution, from the viewpoint of further improving the applicability to a substrate or the like. Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol. The organic solvent may be used alone or in combination of two or more kinds. The organic solvent may be the same as that used in the synthesis of the adhesive resin, or one or more organic solvents other than those used in the synthesis may be added.

[0053] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 5 to 100 μm, more preferably 10 to 80 μm, and even more preferably 15 to 60 μm. When the thickness of the adhesive layer is at least the above lower limit, excellent adhesiveness is obtained, and the surface of the workpiece tends to be better protected during processing.

[0054] As the protective sheet for workpiece processing, a commercially available product may be used, for example, "ADWILL E-3125KN" manufactured by Lintec Corporation. The thickness of the above-mentioned protection sheet for workpiece processing is not particularly limited, but is usually 70 to 400 μm, and preferably 100 to 300 μm.

[0055] [Grinding and Slicing Process (C)] The grinding and singulating step (C) is a step of grinding the back surface of the workpiece to singulate the workpiece into a plurality of singulated workpieces starting from the modified regions or grooves. The workpiece to which the protective sheet for workpiece processing is attached and which has the modified regions or grooves formed therein may be fixed on the substrate side of the protective sheet for workpiece processing by a support means, which is not particularly limited, but is preferably a support means such as a chuck table that suctions and holds the object to be fixed.

[0056] Next, the back surface of the fixed workpiece is ground to separate the workpiece into a plurality of individual workpieces. In the back grinding, if a modified region is formed on the workpiece by step a, the grinding surface may reach the modified region, but it does not have to reach the modified region strictly. In other words, it is sufficient to grind to a position close to the modified region so that the workpiece is destroyed starting from the modified region and divided into individual workpieces. On the other hand, if grooves are formed in the workpiece by step b, the workpiece is ground at least to a position where the grinding surface reaches the bottom of the groove. This back grinding turns the grooves into cuts that penetrate the workpiece, and the workpiece is divided by the cuts into individual workpiece pieces.

[0057] The thickness of the individual workpieces obtained by grinding and dividing the workpiece is preferably less than 50 μm, more preferably 5 to 30 μm, and even more preferably 10 to 25 μm. The thickness of the workpiece singulation is measured at any 10 points using a constant pressure thickness gauge and the average value is calculated. Specifically, it can be measured by the method described in the examples.

[0058] The total thickness variation (TTV) of the individual workpieces obtained by grinding and dividing the workpiece is preferably less than 3 μm, more preferably less than 2 μm, and even more preferably less than 1 μm. The TTV of the workpiece diced can be determined by measuring the thickness of the entire surface of the workpiece diced using a thickness measuring device and calculating the difference between the maximum thickness and the minimum thickness. Specifically, it can be measured by the method described in the examples.

[0059] The shape of the individual workpieces may be square or may be an elongated shape such as a rectangle. The size of the individual workpieces is not particularly limited, but is preferably 400 mm 2 Less than 150mm, preferably 2 Less than 50 mm, more preferably 2 is less than.

[0060] [Step (D): Step of irradiating the pressure-sensitive adhesive layer with energy rays] Step (D) is a step of irradiating the adhesive layer of the protective sheet for workpiece processing attached to the workpiece with energy rays, and is performed between the sheet attachment step (B) and the grinding and singulation step (C). By performing step (D) before the grinding and singulation step (C) and curing the adhesive layer of the protective sheet for workpiece processing, the grinding surface is stabilized when the backside of the workpiece is ground, and the processing accuracy when grinding and singulating the workpiece can be improved. In addition, adhesive residue on the individual workpieces after singulation can be suppressed.

[0061] The adhesive layer of the protection sheet for workpiece processing is irradiated with energy rays to harden the adhesive. Of the above-mentioned energy rays, ultraviolet rays are preferred as the energy rays used for energy ray irradiation because they are easy to handle. The illuminance of ultraviolet rays is preferably 100 to 400 mW / cm. 2 , more preferably 150 to 350 mW / cm 2 , and more preferably 180 to 300 mW / cm 2 The amount of ultraviolet light is preferably 100 to 2,000 mJ / cm 2 , more preferably 200 to 1,000 mJ / cm 2 , and more preferably 300 to 500 mJ / cm 2 is. The energy rays may be irradiated from any direction as long as they can cure the adhesive layer, but from the viewpoint of efficient curing, they are preferably irradiated from the substrate side of the protective sheet for workpiece processing. In this case, from the viewpoint of enabling sufficient irradiation of the energy rays to the adhesive layer, it is preferable that the substrate and the adhesive layer have energy ray transparency.

[0062] [Step (E): Grinding the substrate surface of the workpiece processing protection sheet] Step (E) is a step of grinding the substrate surface of the workpiece processing protective sheet attached to the workpiece, and is performed between the sheet attaching step (B) and the grinding and singulating step (C). By performing step (E) before the grinding and singulating step (C) and flattening the substrate surface of the workpiece processing protective sheet, the surface pressure during back grinding of the workpiece becomes uniform in the grinding and singulating step (C), and the processing precision when grinding and singulating the workpiece can be improved.

[0063] The grinding of the substrate surface of the above-mentioned protection sheet for workpiece processing is adjusted appropriately according to the irregularities of the workpiece surface, and is continued until the substrate surface becomes flat.

[0064] From the viewpoint of obtaining the effects of the present invention, the thickness variation (TTV) of the above-mentioned protection sheet for workpiece processing is preferably less than 7 μm, more preferably less than 5 μm, and even more preferably less than 3 μm. The TTV of the above-mentioned workpiece processing protection sheet can be determined by measuring the thickness of the entire surface of the workpiece processing protection sheet using a thickness measuring device and calculating the difference between the maximum thickness and the minimum thickness. Specifically, it can be measured by the method described in the examples.

[0065] The order of the steps (D) and (E) is not particularly limited as long as they are performed between the sheet attaching step (B) and the grinding and singulating step (C), and step (E) may be performed after step (D), or step (D) may be performed after step (E). In particular, from the viewpoint of further exerting the effects of the present invention, it is preferable to perform the steps (D) and (E) in this order, and when the planned division line forming step (A) is step a, it is preferable to perform the steps (D) and (E) in this order before step a.

[0066] The manufacturing method of the electronic device of this embodiment may include, after the grinding and singulation step (C), a step (F) of attaching a thermosetting film or dicing tape to the side of the workpiece opposite the workpiece processing protective sheet.

[0067] The thermosetting film is a thermosetting film obtained by forming a film from a resin composition containing at least a thermosetting resin, and is used as an adhesive when mounting a workpiece singulated on a substrate. The thermosetting film may contain a curing agent for the thermosetting resin, a thermoplastic resin, an inorganic filler, a curing accelerator, etc., as necessary. As the thermosetting film, for example, a thermosetting film that is generally used as a die bonding film, a die attach film, a film for forming a protective film on the back surface of a semiconductor, etc. can be used. The thermosetting film may be provided with a support sheet, which may be made of, for example, the resins listed as the base material of the above-mentioned protection sheet for workpiece processing.

[0068] The thickness of the thermosetting film and the dicing tape is not particularly limited, but is usually 1 to 200 μm, preferably 3 to 100 μm, and more preferably 5 to 50 μm.

[0069] A method for attaching the thermosetting film or dicing tape to the plurality of individual workpieces includes, for example, a lamination method. The lamination may be performed with or without heating. When the lamination is performed with heating, the heating temperature is preferably 15 to 90° C. from the viewpoint of suppressing thermal changes in the individual workpieces.

[0070] After the grinding and dividing step (C) or after the step (F) of applying a thermosetting film, the protection sheet for workpiece processing is peeled off from the plurality of divided workpieces.

[0071] It is preferable to divide the thermosetting film to which the plurality of workpieces are attached into pieces having the same shape as the workpieces, thereby obtaining the workpieces with the thermosetting film attached. As a method for dividing the thermosetting film, for example, laser dicing using a laser beam, expanding, fusing, etc. can be applied.

[0072] The workpieces with the thermosetting film are further subjected to an expanding process for widening the gap between the workpieces, a rearrangement process for arranging the widened gap between the workpieces, an inversion process for inverting the workpieces, etc., as needed, and then attached (die-attached) to a substrate from the thermosetting film side. The thermosetting film can then be thermally cured to bond the workpieces to the substrate. [Example]

[0073] The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples.

[0074] The measurement and evaluation methods in the present invention are as follows. (1) Thickness measurement of workpiece (semiconductor chip) The thickness of the semiconductor chip was measured using a constant pressure thickness measuring instrument (manufactured by Teclock Corporation, device name "PG-02"), where measurements were taken at 10 random points and the average value was calculated.

[0075] (2) Semiconductor chip thickness variation (TTV) The thickness variation of the semiconductor chips obtained by the grinding and singulation process (C) was evaluated by measuring the thickness of the entire surface of the semiconductor chip at a measurement pitch of 5 mm using a thickness measurement device (manufactured by Hamamatsu Photonics K.K., product name "C8870"), calculating the difference between the maximum thickness and the minimum thickness as TTV (Total Thickness Variation), and evaluating it based on the following criteria. [Evaluation criteria] A: TTV is less than 2 μm B: TTV is 2 μm or more and less than 3 μm C: TTV is 3 μm or more

[0076] (3) Evaluation of adhesive residue on semiconductor chips The entire circuit surface of the semiconductor chip obtained by the grinding and singulation step (C) was observed using a digital microscope (manufactured by Keyence Corporation, device name "VHX-1000") and evaluated based on the following criteria. [Evaluation criteria] A: No glue residue C: There is glue residue

[0077] (4) Thickness variation (TTV) of the protective sheet (back grind tape) used for workpiece processing after process (E) After grinding the substrate surface of the backgrinding tape in step (E), the backgrinding tape was peeled off from the semiconductor wafer. The thickness of the backgrinding tape was measured at 10 random points using a constant pressure thickness measuring instrument (manufactured by Teclock Corporation, product name "PG-02"), and the difference between the maximum thickness and the minimum thickness was calculated as TTV (Total Thickness Variation), and evaluated based on the following criteria. [Evaluation criteria] A: TTV is less than 5 μm B: TTV is 5 μm or more and less than 7 μm C: TTV is 7 μm or more

[0078] (5) Evaluating whether water has penetrated into the surface of the workpiece (semiconductor wafer) after process (E). After grinding the substrate surface of the backgrinding tape in step (E), the entire circuit surface of the semiconductor wafer was observed using a digital microscope (manufactured by Keyence Corporation, device name "VHX-1000"), and the frequency of water penetration between the circuit surface of the semiconductor wafer and the backgrinding tape was evaluated based on the following criteria. [Evaluation criteria] A: No water intrusion was observed. B: Some areas where water intrusion occurred were observed, but no areas where water intrusion onto the circuit surface was observed. C: Water was found to have infiltrated into the circuit surface.

[0079] [Example 1] [Sheet attachment process (B)] Using a tape laminator (manufactured by Lintec Corporation, device name "RAD-3520F / 12"), backgrinding tape (manufactured by Lintec Corporation, product name "ADWILL E-3125KN") was laminated onto the circuit surface of a semiconductor wafer (a silicon wafer with a diameter of 12 inches, a thickness of 775 μm, and a patterned circuit surface) on a table at room temperature (25°C) so that the adhesive layer surface of the backgrinding tape abutted against the circuit surface.

[0080] [Step (D): Step of irradiating with energy rays] Next, a UV irradiation device (manufactured by Lintec Corporation, device name "RAD-2010m / 12") was used to irradiate the semiconductor wafer with the backgrind tape from the backgrind tape side at an illuminance of 220 mW / cm. 2 , light intensity 380mJ / cm 2 The adhesive layer of the backgrind tape was cured by irradiating it with ultraviolet light under the conditions of

[0081] [Step (E): Grinding the substrate surface of the workpiece processing protection sheet] Next, the substrate surface of the backgrind tape was ground using a grinder (manufactured by Disco Corporation, device name "DGP8760").

[0082] [Step a: Step of forming a modified region inside a workpiece (semiconductor wafer)] Next, using a stealth laser irradiation device (manufactured by Disco Corporation, device name "DFL7361"), a stealth laser was irradiated from the back side of the semiconductor wafer opposite the circuit formation surface, and a modified region was formed inside the wafer by drawing a square measuring 10 mm x 10 mm.

[0083] [Grinding and Slicing Process (C)] Next, using a grinder (manufactured by Disco Corporation, device name "DFG8760"), the backside of the semiconductor wafer opposite the circuit-formed surface was ground while being exposed to ultrapure water, and simultaneously, the semiconductor chips were separated. After that, the backgrinding tape was peeled off from the semiconductor chips. The thickness of the obtained semiconductor chips was 30 μm.

[0084] [Example 2] A semiconductor chip having a thickness of 30 μm was obtained by the same procedure as in Example 1, except that step (E) was carried out between steps (B) and (D).

[0085] [Example 3] A semiconductor chip having a thickness of 30 μm was obtained by the same operation as in Example 1, except that in Example 1, steps (E), a, and (D) were performed in this order between steps (B) and (C).

[0086] [Comparative Example 1] A semiconductor chip having a thickness of 30 μm was obtained by the same procedure as in Example 1, except that steps (B), (E), (a), (C), and (D) were performed in this order.

[0087] [Example 4] [Step b: forming grooves on the surface of the workpiece (semiconductor wafer)] Using a dicing machine (manufactured by Disco Corporation, machine name "DFD6361"), half-cut dicing was performed on the circuit surface of a semiconductor wafer (a silicon wafer with a diameter of 12 inches, a thickness of 775 μm, and a circuit surface on which a pattern was formed), by cutting a groove from the surface to a depth of 50 μm with a dicing blade so as to draw a square measuring 10 mm x 10 mm.

[0088] [Sheet attachment process (B)] Next, using a tape laminator (manufactured by Lintec Corporation, device name "RAD-3520F / 12"), backgrinding tape (manufactured by Lintec Corporation, product name "ADWILL E-3125KN") was laminated on a table at room temperature (25°C) so that the adhesive layer surface of the backgrinding tape was in contact with the circuit surface of the semiconductor wafer on which the above grooves had been formed.

[0089] [Step (D): Step of irradiating with energy rays] Next, a UV irradiation device (manufactured by Lintec Corporation, device name "RAD-2010m / 12") was used to irradiate the silicon wafer with the backgrind tape from the backgrind tape side at an illuminance of 220 mW / cm. 2 , light intensity 380mJ / cm 2 The adhesive layer of the backgrind tape was cured by irradiating it with ultraviolet light under the conditions of

[0090] [Step (E): Grinding the substrate surface of the workpiece processing protection sheet] Next, the substrate surface of the backgrind tape was ground using a grinder (manufactured by Disco Corporation, device name "DGP8760").

[0091] [Grinding and Slicing Process (C)] Next, using a grinder (manufactured by Disco Corporation, device name "DFG8760"), the backside of the semiconductor wafer opposite to the circuit side on which the above-mentioned grooves were formed was ground while being exposed to ultrapure water, and simultaneously, the semiconductor chips were separated. After that, the backgrinding tape was peeled off from the semiconductor chips. The thickness of the obtained semiconductor chips was 30 μm.

[0092] [Example 5] A semiconductor chip having a thickness of 30 μm was obtained by the same procedure as in Example 4, except that step (E) was carried out between steps (B) and (D).

[0093] Comparative Example 2 A semiconductor chip having a thickness of 30 μm was obtained by the same procedure as in Example 4, except that in Example 4, step b, step (B), step (E), step (C), and step (D) were performed in this order.

[0094] [Table 1]

[0095] In Examples 1 to 4, in which steps (D) and (E) were performed between the sheet-attaching step (B) and the grinding and singulating step (C), no adhesive residue remained on the semiconductor chips, the TTV of the semiconductor chips was small, and the processing precision during grinding and singulating of the semiconductor wafer was excellent. Furthermore, no water penetration into the circuit surface of the semiconductor wafer was observed after step (E).

Claims

1. A dividing line forming step (A) is a step (a) of forming a modified region inside the workpiece from the front or back surface of the workpiece, or a step (b) of forming a groove on the surface of the workpiece; a sheet attaching step (B) of attaching a workpiece processing protection sheet having an energy ray curable adhesive layer on a substrate to the surface of the workpiece, with the energy ray curable adhesive layer as an attachment surface, before the step (a) or after the step (b); A grinding and singulation step (C) of grinding the back surface of the workpiece to singulate the workpiece into a plurality of workpiece singulations starting from the modified region or groove, The method for manufacturing an electronic device further includes the following steps (D) and (E) between the sheet attaching step (B) and the grinding and singulating step (C), and step (D) is performed after step (E). Step (D): A step of irradiating the energy ray-curable adhesive layer of the workpiece processing protection sheet attached to the workpiece with energy rays. Step (E): A step of grinding the substrate surface of the workpiece processing protection sheet attached to the workpiece

2. The method for manufacturing an electronic device according to claim 1 , wherein the step (A) of forming the planned division lines is step a.

3. The method for manufacturing an electronic device according to claim 1 , wherein the step (A) of forming the planned division lines is step b.

4. The method for manufacturing an electronic device according to claim 2 , wherein the step (E) and the step (D) are carried out in this order before the step (a).

5. The method for manufacturing an electronic device according to any one of claims 1 to 4, wherein the thickness of the workpiece obtained by the grinding and singulating step (C) is less than 50 µm.

6. A method for manufacturing an electronic device apparatus described in any one of claims 1 to 5, comprising, after the grinding and singulation process (C), a process (F) of attaching a thermosetting film or dicing tape to the side of the workpiece opposite the workpiece processing protective sheet.

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