TWI811763B - Adhesive sheet and manufacturing method of processed product - Google Patents

Abstract

The present invention relates to an adhesive sheet and a method for manufacturing a processed product. The adhesive sheet provided by the present invention is a plate-shaped component that is irradiated with laser light to form a modified portion, which is used to divide the plate-shaped component into wafers. The adhesive sheet has a base material and an adhesive layer provided on one side of the base material. The base material has a base material with respect to the one side and both sides opposite to the one side, in accordance with JIS B0601:2013 (ISO 4287). :1997), the arithmetic mean roughness Ra is 0.01 μm or more and 0.2 μm or less, and the thickness of the adhesive layer is 2 μm or more and 12 μm or less. This kind of adhesive sheet is difficult to produce defects and has excellent pick-up properties when used in laser cutting processes.

Description

Manufacturing method of adhesive sheet and processed article

The present invention relates to an adhesive sheet and a method for manufacturing a processed product; in particular, it relates to an adhesive sheet that irradiates a plate-shaped component with laser light to form a modified portion for individualizing the plate-shaped component to obtain a wafer-shaped processed product. , and a method of using the above-mentioned adhesive sheet to manufacture wafers and other processed products.

After the circuit is formed on the surface of the semiconductor wafer, the backside of the wafer is ground and processed, a backside grinding process is performed to adjust the thickness of the wafer, and a cutting process is performed to separate the wafer into required wafer sizes.

Recently, with the reduction in the size of electronic equipment casings and the increase in demand for semiconductor devices using multi-layer wafers, the semiconductor wafers that constitute the components are continuing to become thinner. Therefore, the original thickness of the wafers is about 350 μm, and the thickness is required to be thinner. To 50~100μm or below this thickness.

As fragile component wafers become thinner, the risk of damage during processing and transportation also increases. If a wafer with such a thickness is cut by a high-speed rotating cutting knife, especially the back side of the semiconductor wafer, cracking of the wafer will occur, which will significantly reduce the flexural strength of the wafer.

Therefore, the patent document discloses a so-called stealth dicing method that irradiates the inside of a semiconductor wafer with laser light, selects a portion to form a modified portion and forms a dicing line, and cuts the semiconductor wafer based on the modified portion (patent document 1). According to the stealth dicing method, after irradiating the inside of the semiconductor wafer with laser light to form a modified part, the thin semiconductor wafer is pasted on an adhesive sheet (dicing sheet) composed of a base material and an adhesive layer. By cutting the dicing sheet After extending and dividing (cutting) the semiconductor wafer along the cutting lines, the semiconductor wafer can be produced with good yield. In addition, it is also disclosed that after the semiconductor wafer is adhered to the dicing piece, the modified portion is formed by irradiation with laser light. By using such a process to form the modified portion, the risk of damage to the fragile wafer can be reduced because there is no need to go through the process of sticking dicing tape on the fragile wafer. In such a case, since laser is generally irradiated on the surface of the wafer where no circuit is formed, it is necessary to irradiate the laser through the dicing chip.

As in the above-mentioned cutting process, lasers are sometimes used as a processing method. In the cutting process, lasers are also used as tools for accurately aligning plate-shaped components such as semiconductor wafers. In the same cutting process as above, when laser light is used, the adhesive sheet used (this adhesive sheet is called "laser cutting sheet" in the patent specification of the present invention), during the use process, the laser When the laser is transmitted through the cutting sheet, the laser light must have excellent penetrability.

In order to meet such requirements, for example, Patent Document 2 discloses that a laser cutting sheet formed of a base material and an adhesive layer formed on one side has a total light transmittance of 60% or more in the wavelength range of 300 to 400 nm. , the haze is less than 20%, the width of the optical comb is 0.25mm, and the penetration clarity is more than 30 laser cutting sheets. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Publication No. 2005-229040 [Patent Document 2] Patent No. 5124778

In Patent Document 2, as the above-mentioned laser cutting sheet, the center line average roughness Ra of one side of the base material is greater than the center line average roughness Ra of the other side surface, so that the center line average roughness Ra is larger than the surface of the base material. It consists of forming an adhesive layer. The surface with average center line roughness Ra of 0.3 to 0.7 μm is used as the adhesive layer forming surface. The surface opposite to the surface of the base material has an average center line roughness Ra of 0.14 μm. Cutting sheet (Patent Document 2 Example).

This kind of laser cutting sheet has a smooth surface opposite to the surface where the adhesive layer of the base material is formed on the side where the laser is incident, which can prevent the laser light on the surface of the base material from being scattered, so as to effectively utilize the laser light.

However, the thickness of processed products such as semiconductor wafers, which are manufactured on plate-shaped components such as semiconductor wafers using laser cutting wafers, tends to become thinner. In addition, the recent high-density implementation continues, and sometimes The substrate is replaced with a polysiloxane wafer, and a silicon (Si) through-electrode (TSV, Through-Silicon Via) is used to stack the wafer on top of it. Similarly, when the workpiece is thin or has a structure related to TSV, the adhesive layer of the laser cutting sheet can be easily peeled off from the workpiece attached to the adhesive layer (excellent pick-up properties) ) is better.

On the other hand, the laser cutting sheet described in Patent Document 2 may have a portion where the adhesive layer cannot be properly formed on the base material. Such a portion is regarded as a system when viewed from the plane of the laser cutting sheet. Defects may cause unevenness in the light reaching the plate-shaped component of the laser incident for processing the plate-shaped component.

The present invention is an adhesive sheet used when laser light is used in the cutting process. The purpose is to provide an adhesive sheet that is difficult to cause defects and has excellent pick-up properties, and to provide a plate-shaped component using this adhesive sheet. Methods of manufacturing processed products.

In order to achieve the above object, the present inventors have conducted in-depth research and found that by setting the thickness of the adhesive layer to 2 μm or more and 12 μm or less, and setting the arithmetic average roughness Ra of both sides of the base material to 0.2 μm or less, a stable product can be obtained. New knowledge on adhesive sheets that greatly reduce the possibility of defects and at the same time have superior pick-up properties. The present invention is completed based on the above-mentioned new knowledge, and the contents are as follows.

(1) An adhesive sheet, which is formed by irradiating a plate-shaped component with laser light to form a modified portion, and is used to divide the above-mentioned plate-shaped component into wafers, and is characterized in that: it has a base material and one side of the above-mentioned base material The adhesive layer provided on the surface of the base material shall have an arithmetic mean roughness Ra of 0.01 μm or more as specified in JIS B0601:2013 (ISO 4287:1997) for the above-mentioned one surface and the two surfaces opposite to the above-mentioned one surface. , 0.2 μm or less, and the thickness of the above-mentioned adhesive layer is 2 μm or more and 12 μm or less.

(2) The adhesive sheet described in item (1) above. The haze of the adhesive sheet specified in JIS K7136:2000 (ISO 14782:1999) is 0.01% when the base material side is the incident side. Above and below 10%.

(3) The adhesive sheet described in the above item (1) or (2), the above-mentioned adhesive layer contains an acrylic polymer, and the glass transition temperature Tg of the above-mentioned acrylic polymer is -40°C or above, - Below 10℃.

(4) The adhesive sheet according to the above item (3), wherein the acrylic polymer contains a structural unit derived from methyl methacrylate, and methyl methacrylate is a monomer integral to the acrylic polymer. The mass ratio is 5 mass% or more and 20 mass% or less.

(5) The adhesive sheet according to the above item (3) or (4), wherein the acrylic polymer has an energy ray polymerizable group.

(6) The adhesive sheet according to any one of the above items (1) to (5), wherein the base material contains a polyolefin material.

(7) In the adhesive sheet according to any one of the above items (1) to (6), the arithmetic mean roughness Ra of the base material is set including the pressure of the base material roller.

(8) In the adhesive sheet described in the above item (7), the roller used in the roller pressing has a surface made of a metal material.

(9) A method of manufacturing a processed article, including: pasting the surface of the adhesive sheet described in any one of the above items (1) to (8) that is closer to the adhesive layer than the above-mentioned base material. A bonding process for obtaining a first laminated body having the above-mentioned adhesive sheet and the above-mentioned plate-like component by extending the above-mentioned base material having the above-mentioned first laminated body, dividing the above-mentioned bonding The above-mentioned plate-shaped component on the chip, a dividing process of obtaining a plurality of wafers having divided bodies of the above-mentioned plate-shaped component, and disposing the second laminated body formed on the above-mentioned adhesive sheet; and the above-mentioned plurality of wafers having the above-mentioned second laminated body A lifting process in which the above-mentioned wafers are separately separated from the above-mentioned adhesive sheets and obtained as processed objects; characterized in that: until the start of the above-mentioned dividing process, laser light is irradiated to focus on the focus set inside the above-mentioned plate-shaped component. A modified portion forming process for forming a modified portion inside the plate-shaped component.

(10) The manufacturing method of the processed article described in the above item (9), the above-mentioned first laminated body provided in the above-mentioned dividing process has an additional layer between the above-mentioned adhesive layer and the above-mentioned plate-shaped component, and the above-mentioned first laminated body is provided in the above-mentioned dividing process. The dividing process simultaneously divides the above-mentioned additional layer. In the above-mentioned lifting process, the wafer separated from the above-mentioned adhesive sheet has a segmented body of the above-mentioned plate-shaped component, and the segmented body of the plate-shaped component is formed on the surface of the above-mentioned adjacent adhesive sheet. A segmented body of the above additional layer.

(11) The method for manufacturing a processed article according to the above item (10), wherein the additional layer has a protective layer.

(12) The method for manufacturing a processed article according to the above item (11), including a protective film forming process of forming the protective layer of the first laminated body from a protective film forming film until the start of the dividing process.

(13) The method for manufacturing a processed article according to the above item (10), wherein the additional layer has a grain bonding layer.

The present invention provides an adhesive sheet that is less likely to cause defects and has excellent pick-up properties. In addition, by using this adhesive sheet, processed objects can be stably manufactured on plate-shaped components.

Embodiments of the present invention will be described in detail below.

1. Adhesive sheet An adhesive sheet according to one embodiment of the present invention includes a base material and an adhesive layer.

(1)Substrate The base material of the adhesive sheet according to one embodiment of the present invention has a surface opposite to the adhesive layer (referred to as the "adhesive processed surface" in the patent specification of the present invention) and a surface opposite to the adhesive processed surface. (referred to as the "laser incident surface" in the patent specification of this invention), the arithmetic mean roughness Ra specified in IS B0601:2013 (ISO 4287:1997) (the "arithmetic mean roughness not specified below" Ra" means this meaning) is 0.2μm or less. The arithmetic average roughness Ra of these surfaces is 0.2 μm or less, making it difficult to observe defects on the adhesive sheet in plan view. Therefore, the laser light incident on the base material side of the adhesive sheet can easily reach the adhesive sheet uniformly. For pasted plate components, when the laser light reaches the plate component unevenly, for example, a portion where the modified portion is not properly formed within the plate component increases, thereby improving the individuality of the plate component produced from this part. There is the possibility of problems such as fragmentation not being performed properly. From the perspective of improving the uniformity of the incident laser light, for both the adhesive processing surface and the laser incident surface, the arithmetic average roughness Ra is preferably 0.18 μm or less, more preferably 0.16 μm or less, and more preferably The best one is below 0.14μm, the best one is below 0.12μm. From the viewpoint of obtaining an adhesive sheet that is unlikely to have planar defects, there is no limit to the lower limit of the arithmetic mean roughness Ra of the adhesive processed surface. From the viewpoint of maintaining manufacturing stability, etc., it is preferable that the arithmetic mean roughness Ra is 0.01 μm or more for both the adhesive processing surface and the laser incident surface.

The constituent material of the base material according to one embodiment of the present invention satisfies the above-mentioned relevant conditions for the arithmetic mean roughness Ra, and can be used as the base material of the laser cutting sheet, that is, as long as the laser light at the required wavelength can There is no special limit on the penetration rate within the practical range, as long as it can meet the requirements of being difficult to break even if it extends in the in-plane direction or protrudes in the local thickness direction. The base material according to one embodiment of the present invention is usually composed of a film whose main material is a resin material. This film can be a single layer or a laminated body.

Specific examples of resin materials included in this film include: polypropylene such as random copolymerized polypropylene and block copolymerized polypropylene; low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene Polyethylene such as polyethylene (HDPE); ethylene copolymers such as ethylene/vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, ethylene-norbornene copolymer, etc. ; Norbornene resin and other cyclic olefin polymers (COP) polybutene, polybutadiene, polymethylpentene and other polyolefin materials; PVC, vinyl chloride copolymer and other polyvinyl chloride materials; polyvinyl chloride materials Polyester materials such as ethylene phthalate and poly(butylene terephthalate); polyurethane materials; polyimide materials; ionomer resin materials; homologs of alkyl (meth)acrylates Polyacrylic materials such as polymers and copolymers of alkyl (meth)acrylates; polystyrene materials; polycarbonate materials; fluororesin materials; and hydrogenated and denatured materials of such resin materials Resin materials as the main materials. The resin material can also be a bridge between the above-mentioned materials and a bridge agent. In addition, "(meth)acrylic acid" in the patent specification of the present invention means both acrylic acid and methacrylic acid, and the same applies to other similar terms. The resin material provided on the base material may be a single type or a mixture of two or more types. From the viewpoints of high laser penetration, ease of local deformation in the in-plane direction and thickness direction, low environmental load, etc., the base material according to one embodiment of the present invention preferably contains a polyolefin material. , among polyolefin materials, polypropylene containing random copolymerized polypropylene, etc. is preferred.

When the resin material included in the base material is a polyolefin material, generally speaking, the arithmetic surface roughness Ra on both sides of the base material can be controlled by pressing two rollers through a roller embedded in the base material. By adjusting the surface material constituting the rollers and the roughness of the surface, the arithmetic surface roughness Ra of both sides of the base material is set. Traditionally, the surface of these rollers has been generally made of metal on one side and an elastic material like rubber on the other side. Therefore, the arithmetic surface roughness Ra of the base material contacting the roller made of metal can be It is relatively easy to perform with a low numerical value, but it is difficult to perform with a low numerical value for the arithmetic surface roughness Ra of the surface of the base material in contact with the roller formed of an elastic material. Here, as with the base material according to one embodiment of the present invention, when it is desired to reduce the double-sided arithmetic surface roughness Ra of the base material, metal is used on both sides of the roller required for roller pressing. It is better to proceed with the formed surface. However, in this case, compared with the case where the surface of one roller is made of elastic material, the relative arrangement of the rollers on both sides and the base material needs to be more strictly controlled. The resin material included in the base material is polyvinyl chloride. In the case of materials, since the base material can be manufactured by inflation molding, the arithmetic surface roughness Ra of both sides of the base material can be easily set to a low value. However, since polyvinyl chloride materials contain halogen elements, it is better not to use them as base materials in order to reduce environmental load.

The base material is a film with the above-mentioned resin material as the main material, and may also contain various additives such as colorants, flame retardants, plasticizers, antistatic agents, lubricants, and fillers. Examples of colorants include pigments such as titanium dioxide and carbon black, or various dyes. In addition, examples of fillers include organic materials such as melamine resin, inorganic materials such as fumed silica, and metallic materials such as nickel steel particles. Although the content of this additive is not particularly limited, it must be within a range that can perform the required functions of the base material, especially the function of penetrating the laser, without losing the required smoothness and softness.

In order to harden the adhesive layer, when using ultraviolet rays as the energy rays to be irradiated, it is preferable that the base material is transparent to ultraviolet rays. In addition, when using electron beams as energy rays, it is preferable that the base material has electron beam penetrability.

In terms of the thickness of the base material, there is no particular restriction on the thickness of the adhesive sheet as long as it can function properly in the above-mentioned processes. Preferably, it is in the range of 20 to 450 μm, and more preferably, it is in the range of 25 to 200 μm. range, the best range is between 50 and 150μm.

The Young's modulus of the base material is preferably 50 to 500 MPa. By keeping the Young's modulus within this range, good ductility can be maintained, while the mechanical strength of the base material can be improved, resulting in good process properties when forming the adhesive layer. For example, when a polyolefin-containing resin film serving as a base material is placed in a coater, unintentional expansion of the base material when tension is applied can be prevented. From the viewpoint that the above-mentioned Young's modulus is difficult to cause blocking and has relatively good expandability while improving mechanical strength, 60 to 450 MPa is preferred, 100 to 420 MPa is more preferred, and 150 to 300 MPa is particularly preferred.

(2) Adhesive layer The thickness of the adhesive layer of the adhesive sheet according to one embodiment of the present invention is 2 μm or more and 12 μm or less. By having the thickness of the adhesive layer within the above range and the double-sided arithmetic average roughness Ra of the base material within the range mentioned above, it is possible to obtain a product that is difficult to produce defects when viewed from a plan view and has excellent pick-up properties. Adhesive sheet. From the viewpoint of relatively stably reducing the possibility of occurrence of defects, the thickness of the adhesive layer is preferably 3 μm or more, more preferably 4 μm or more. From the viewpoint of more stably realizing an adhesive sheet with excellent pick-off properties, the thickness of the adhesive layer is preferably 10 μm or less, more preferably 8 μm or less, and particularly preferably 6 μm or less.

The adhesive composition used to form the adhesive layer of the adhesive sheet according to one embodiment of the present invention is not limited. Examples of the adhesive included in the adhesive composition include: Rubber, acrylic, polysiloxane, polyvinyl ether and other adhesives. Hereinafter, description will be given as an example in which the adhesive composition used to form the adhesive layer contains an acrylic adhesive. Acrylic adhesives have excellent transparency and can easily penetrate laser light.

Acrylic adhesives contain acrylic polymers. An acrylic polymer is a polymer containing a structural unit based on an acrylic compound as a unit constituting the skeleton. Acrylic polymers can be homopolymers formed by the polymerization of one monomer, or they can be copolymers formed by the polymerization of multiple monomers. From the viewpoint of easy control of the physical and chemical properties of the polymer, an acrylic polymer copolymer is preferred.

The glass transition temperature Tg of the acrylic polymer is preferably -40°C or more and -10°C or less. By including an acrylic polymer with a glass transition temperature Tg of -40°C or higher in the adhesive composition, the adhesiveness of the adhesive layer can be reduced and the retrieval properties can be further improved. From the viewpoint of obtaining the effect of improving the pickability more stably, it is more preferable that the glass transition temperature Tg of the acrylic polymer is -35°C or higher. From the viewpoint of easily maintaining the wafer performance after the wafer is divided, the glass transition temperature Tg of the acrylic polymer is preferably -20°C or lower.

The weight average molecular weight (Mw) of the acrylic polymer is not limited, but is generally preferably 100,000 to 2,000,000, more preferably 300,000 to 1,500,000. In addition, the molecular weight distribution (Mw/Mn, Mn coefficient average molecular weight) is also not limited, but generally, 1.0 to 10 is preferred, and 1.0 to 3.0 is more preferred.

The specific type of monomer used in the acrylic polymer is not limited. Examples of such monomers include: (meth)acrylic acid, (meth)acrylic acid ester, acrylonitrile, and the like. Specific examples of (meth)acrylate include: (methyl)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylate Alkyl carbon number systems such as 2-ethylhexyl acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, pentadecyl (meth)acrylate, and stearyl (meth)acrylate are from 1 to Alkyl (meth)acrylate of 18; cycloalkyl (meth)acrylate, benzyl (meth)acrylate, isobornyl acrylate, dicyclopentyl acrylate, dicyclopentenyl acrylate , dicyclopentenyl hydroxyethyl acrylate, acyl imino acrylate and other (meth)acrylates with cyclic skeleton; 2-(meth)hydroxyethyl acrylate, 2-(meth)hydroxyethyl acrylate (meth)acrylates having a hydroxyl group such as propyl ester; (meth)acrylates having an epoxy resin group such as glycidyl methacrylate and glycidyl acrylate.

From the viewpoint that the acrylic polymer increases the glass transition temperature Tg, it is preferable to contain methyl methacrylate. Since the acrylic polymer contains methyl methacrylate, from the viewpoint of obtaining a more stable effect, the quality of the methyl methacrylate as a whole monomer that is provided to the acrylic polymer is better. 5 mass% or more and 20 mass% or less, more preferably 7 mass% or more and 15 mass% or less.

The acrylic polymer may be a copolymer containing vinyl acetate, styrene, vinyl acetate, etc. as a monomer.

The acrylic polymer may have at least one reactive functional group (hereinafter referred to as "reactive functional group") that can react with the energy ray polymerizable group and the bridge agent.

When an acrylic polymer contains an energy ray polymerizable group, by irradiating the adhesive layer with energy rays, it is easier to obtain an adhesive that reduces the adhesion to the adherend and has superior retractability. piece. Examples of the energy ray polymerizable group include groups having a polymerizable double bond. The preparation method of an acrylic polymer having an energy ray polymerizable group is not limited. As one example of such a preparation method, an acrylic polymer having a functional group containing active hydrogen such as a hydroxyl group, a carboxylic acid group, an amine group, etc. , functional groups capable of reacting with the above-mentioned functional groups such as isocyanate groups, and substances having energy ray polymerizable groups (specific examples include (meth)acrylic acid ethoxy isocyanate). In addition, when the acrylic adhesive contains an acrylic polymer containing an energy ray polymerizable group through this adjustment method, the glass transition temperature Tg of the above-mentioned acrylic polymer can be equal to the above-mentioned The functional group that the functional group reacts with, and the Tg before the substance having the energy ray polymerizable group reacts.

When the acrylic polymer has a reactive functional group, the reactive functional group reacts with the bridging agent to adjust the cohesion of the adhesive layer, suppressing the generation of residue on the adherend after the adhesive sheet is peeled off, or causing the adhesion to deteriorate. The adhesiveness of the agent layer is low, making it easier to improve the pick-up properties. The combination of the reactive functional group and the bridging agent is not limited. Examples of the reactive functional group include groups having active hydrogen such as hydroxyl group, carboxylic acid group, and amine group. Examples of bridging agents include: isocyanate bridging agents, epoxy resin bridging agents, aziridine bridging agents, metal clamp bridging agents, etc. The isocyanate bridging agent contains at least a polyisocyanate compound containing multiple isocyanate groups. Examples of polyisocyanate compounds include toluyl diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate and other aromatic polyisocyanates; dicyclohexylmethane-4,4 '-Diisocyanate, bicycloheptane triisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, methyl cyclohexyl diisocyanate, hydrogenated xylene Alicyclic isocyanate compounds such as diisocyanate; non-cyclic aliphatic isocyanates such as cyclohexane diisocyanate, trimethylcyclohexane diisocyanate, and lysine diisocyanate Acid salts, biurets and isocyanates, compounds with isocyanate groups and ethylene glycol, trimethylolpropane, castrate oil, etc. and non-aromatic low molecular active hydrogen compounds Isotropic forms of adducts of reactants.

For epoxy resin bridging agents, examples include: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m -Xylylenediamine, ethylene glycol diglycidyl ether, 1,6-diol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidyl, glycidylamine, etc.

Examples of aziridine bridging agents include: diphenylmethane-4,4'-bis(1-aziridinemethamide), trimethylolpropane tri-β-aziridine propionic acid, tetrakis Methylmethane tri-β-aziridine propionic acid, toluene-2,4-bis(1-azicyclopropanemethamide), trisethylene melamine, bisisophthalacyl-1-(2-methyl nitrogen ring) propane), tris-1-(2-methylaziridine)phosphine, trimethylolpropane tri-β-(2-methylaziridine)propionate, etc.

Among metal chelate-based bridging agents, metal atoms include chelate compounds such as aluminum, zirconium, titanium, zinc, iron, and tin. Among these, aluminum chelate compounds are preferred because of their excellent performance. Examples of aluminum chelate compounds include diisopropoxyaluminum monooleyl acetyl acetate, monoisopropoxyaluminum bisoil acetoacetate, and monoisopropoxyaluminum monooleate monooleate. Aluminum diisopropoxide acetyl acetate, aluminum diisopropoxide monolauryl acetyl acetate, aluminum diisopropoxide monostearyl acetate, aluminum diisopropoxide monoisostearyl acetate Acetyl acetate, etc.

When the adhesive composition contains an acrylic polymer, the adhesive composition may contain components other than the acrylic polymer. As such a material, an energy ray polymerizable compound can be cited as an example. Energy ray polymerizable compounds are compounds polymerized by irradiation with energy rays such as ultraviolet rays and electron beams. Examples of such energy ray polymerizable compounds include low molecular weight compounds (monofunctional and polyfunctional monomers and oligomeric compounds) having an energy ray polymerizable group. Polymer) as an example, specific examples include: trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, neopentylerythritol triacrylate, pentaerythritol monohydroxypentyl acrylate, pentaerythritol hexyl acrylate, or 1,4-Butene glycol diacrylate, 1,6-hexanediol diacrylate, dicyclopentadiene dimethoxy diacrylate, isobornyl acrylate, etc. containing cyclic aliphatic skeleton Acrylates; polyethylene glycol diacrylate, low polyester acrylate, urethane acrylate oligomer, epoxy resin modified acrylate, polyether acrylate and other acrylate compounds. This compound has at least one polymerizable double bond in its molecule, and its molecular weight is usually about 100 to 30,000, preferably about 300 to 10,000. When the adhesive composition is an acrylic adhesive and contains an acrylic polymer containing an energy ray polymerizable group, even if the adhesive composition does not contain a low molecular weight compound having an energy ray polymerizable group, or only Containing a small amount, by irradiating the adhesive layer with energy rays, the adhesion to the adherend can still be reduced. When the adhesive composition contains a large amount of a low molecular weight compound with an energy ray polymerizable group, the adhesion properties tend to be reduced. Therefore, the adhesive composition is an acrylic adhesive. By containing an acrylic polymer containing an energy ray polymerizable group, the usage amount of a low molecular weight compound having an energy ray polymerizable group can be reduced, thereby further improving the extraction property. When the adhesive composition is an acrylic adhesive, the adhesive composition preferably contains 0 to 30 parts by mass of the energy ray polymerizable compound based on 100 parts by mass of the acrylic polymer, and preferably contains 0 to 15 parts by mass. It is better to contain 0 to 10 parts by mass.

When the adhesive composition contains an acrylic polymer containing an energy ray polymerizable group, or an energy ray polymerizable compound, it is preferred that it also contains a photopolymerization initiator. An example of the photopolymerization initiator is benzoin. Compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds and other photoinitiators; Photosensitizers such as amines and quinones can also be cited as examples. Specifically, examples include: 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ester, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, Tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diethyl, β-chloroanthraquinone, 2,4,6-trimethylbenzyl-diphenyl-phosphine Oxides etc. By containing a photopolymerization initiator, when ultraviolet rays are used as energy rays, it can be carried out with a small irradiation time and irradiation amount.

Examples of the energy ray used to react the energy ray polymerizable group and the energy ray polymerizable compound include ionizing radiation, that is, X-rays, ultraviolet rays, electron beams, and the like. Among these, ultraviolet rays that are relatively easy to prepare for irradiation equipment are preferred.

When using ultraviolet rays as ionizing radiation, from the viewpoint of ease of handling, near ultraviolet rays including ultraviolet rays with a wavelength of approximately 200 to 380 nm may be used. The amount of ultraviolet light can be appropriately selected depending on the type of energy ray polymerizable group and energy ray polymerizable compound contained in the adhesive layer, and the thickness of the adhesive layer, and is usually 50 to 500 mJ/cm ² Around 100 to 450mJ/cm ² is preferred, and 150 to 400mJ/cm ² is more preferred. In addition, the illuminance of ultraviolet rays is usually about 50 to 500 mW/cm ² , preferably 100 to 450 mW/cm ² , and more preferably 150 to 400 mW/cm ² . The ultraviolet source is not particularly limited, and for example, high-pressure mercury lamps, metal halide lamps, etc. can be used.

When using electron beams as ionizing radiation, the accelerating voltage can be appropriately selected according to the type of energy ray polymerizable group and energy ray polymerizable compound contained in the adhesive layer, and the thickness of the adhesive layer. Normally, acceleration The voltage is preferably about 10 to 1000kV. In addition, the irradiation dose should be set within a range in which the reaction between the energy ray polymerizable group and the energy ray polymerizable compound contained in the adhesive layer can proceed appropriately, and is usually selected in the range of 10 to 1000 krad. The electron beam source is not particularly limited, and examples thereof include a Cockcroft-Walton accelerator, a Van de Graaff accelerator, a resonant transformer accelerator, and an insulated core transformer accelerator. , or various electron beam accelerators such as linear, high-frequency and high-voltage (Dynamitron) accelerators, and high-frequency accelerators.

(3) Optical properties The haze of the adhesive sheet according to one embodiment of the present invention specified in JIS K7136:2000 (ISO 14782:1999) is 0.01 compared to the adhesive layer when the surface adjacent to the base material is used as the incident surface. More than % and less than 10% is better. By setting the haze to 10% or less, the laser light incident on the adhesive sheet can be effectively utilized. From the viewpoint of more stably and effectively utilizing the laser light incident on the adhesive sheet, the above-mentioned haze is preferably 5% or less, and more preferably 2.5% or less. From a viewpoint, there is no lower limit to the haze, but from the viewpoint of improving manufacturing stability, the haze is preferably about 0.01% or more.

The total light transmittance of the adhesive sheet according to one embodiment of the present invention specified in JIS K7375:2000 is preferably 85% or more when the surface adjacent to the base material is used as the incident surface compared with the adhesive layer. . With a total light transmittance of over 85%, the laser light incident on the adhesive sheet can be effectively utilized. From the perspective of effectively utilizing the laser light incident on the adhesive sheet, the above total light transmittance is preferably 90% or more; from the perspective of effectively utilizing the laser light incident on the adhesive sheet, the above total light transmittance is not There is an upper limit; and from the viewpoint of improving manufacturing stability, the above-mentioned total light transmittance is preferably about 99.99% or less.

(4)Additional layer The adhesive sheet according to one embodiment of the present invention has an additional layer formed on the surface on the adhesive layer side. When the adhesive sheet is used, the plate-shaped component of the adherend of the adhesive sheet can also be adhered to the above-mentioned additional layer. The composition of the additional layer is not limited, and specific examples of the additional layer include a case where the additional layer has a protective film to form a thin film, or a case where the additional layer has a grain bonding layer.

The protective film forming film is hardened by external energy such as heat and is made of a material that can form a protective film. The protective film forms a thin film or a protective film, and the divided body is separated from the adhesive layer in a state where it is attached to a wafer-shaped component formed by dividing the plate-shaped component into individual pieces. Therefore, when a protective film-forming film is added as a layer, a processed product in which the protective film-forming film or a divided body of the protective film is laminated on one side of the wafer-shaped module can be obtained.

In the case of adding a layer-based grain bonding layer, the wafer-like component formed by individualizing the plate-shaped component is separated from the adhesive layer in a state where the divided bodies of the grain bonding layer are attached. Therefore, when a layer-based grain bonding layer is added, a processed product in which divided bodies of the grain bonding layer are laminated on one side of the wafer-shaped component can be obtained.

(5)Peel-off sheet The adhesive sheet according to one embodiment of the present invention aims to protect the adhesive layer or additional layer during the period until the adhesive layer or additional layer is adhered to the plate-shaped component of the adherend. The peeling surface of the peeling sheet may also be bonded to a surface closer to the adhesive layer than the base material of the adhesive sheet, specifically, the peeling surface of the peeling sheet may be bonded to the surface of the adhesive layer or the surface of the additional layer. The composition of the release sheet is not limited. For example, a release agent can be coated on a plastic film. Specific examples of plastic films include polyester films such as polyethylene terephthalate, poly(butylene terephthalate), and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. Examples of release agents include polysiloxanes, fluorine-based ones, and long-chain alkanes. Among them, polysiloxanes are preferred because they are inexpensive and can obtain stable performance. The above-mentioned release sheet may not use a plastic film, but may use a paper base material such as cellophane, coated paper, or wood paper, or a laminated paper in which a thermoplastic resin such as polyethylene is laminated on the paper base material. The thickness of the release sheet is not particularly limited, but is usually about 20 μm or more and 250 μm or less.

2. Manufacturing method of processed products By using the adhesive sheet according to one embodiment of the present invention described above, a processed object can be produced on a plate-shaped component as described below.

(1) Pasting process First, in the above-mentioned one embodiment of the present invention, the surface of the adhesive sheet that is closer to the adhesive layer than the base material, specifically the surface of the adhesive layer or the surface of the additional layer, is adhered to a surface containing A first laminated body having an adhesive sheet and a plate-shaped component is obtained on one side surface of the adherent body of the plate-shaped component. The plate-shaped component is not limited, and may include, for example, semiconductor wafers such as polysiloxane wafers, or laminates having a structure related to TSV. The thickness of the plate-shaped component is also not limited, for example, it ranges from tens to hundreds of μm.

The first laminated body may have an additional layer. Examples of the additional layer include a protective film-forming film, a protective film formed on the protective film-forming film, and a grain bonding layer. As part of the adhesive sheet, the additional layer can be adhered to the plate-shaped component, or the additional layer can be pre-laminated on one side of the plate-shaped component. In the latter case, the opposite surface of the additional layer to the plate-shaped component serves as one side of the adhesive body containing the plate-shaped component and becomes the surface to which the adhesive sheet is adhered.

(2)Segmentation process By extending the base material having the first laminated body and dividing the plate-shaped components on the adhesive sheet, a second laminated body formed by arranging a plurality of wafers of the divided bodies having the plate-shaped components on the adhesive sheet is obtained. When the first laminated body has an additional layer, the additional layer is also divided by stretching the base material. After the segmentation process is completed, the parts of the base material that have a greater degree of extension are shrunk by heating or other methods, which can also solve the problem of excessive relaxation of the adhesive sheet.

(3) Modified part formation process Before the above-mentioned dividing process starts, the irradiation laser light is focused on the set focus inside the plate-shaped component, and a modified portion is formed inside the plate-shaped component. The wavelength and irradiation method of this laser light are appropriately set according to the composition, thickness and other structures of the plate-shaped component. After the above-mentioned bonding process is completed, when the modified portion forming process is performed, the laser light can also be irradiated to the plate-shaped component through the adhesive sheet. Even in that case, since the adhesive sheet according to one embodiment of the present invention is still difficult to produce defects in plan view, the degree of laser light irradiation changes due to defects and adjacent areas, resulting in plate-shaped components. It is also difficult to cause the problem that the modified part inside becomes inappropriate locally. Similarly, if the modified material in the plate-shaped component is locally inappropriate, there is a concern that the plate-shaped component cannot be properly segmented during the above-mentioned dividing process. If the plate-shaped components cannot be divided appropriately, the possibility of the quality of the processed product being reduced increases.

(4)Pumping process By individually separating the plurality of wafers in the second laminated body from the adhesive sheet, wafers as processed objects can be obtained. The separation method is not limited. Usually, a pin or the like is used to push the opposite surface of the bonding sheet opposite to the chip to locally deform the bonding sheet, thereby improving the adhesion of the adhesive layer of the chip to be separated. Reduced connectivity. Next, a vacuum collet or the like is used to remove the wafer expected to be separated from the adhesive sheet, so that the wafer is separated from the adhesive sheet. In this case, when ejecting the pin or pulling up the wafer from the vacuum collet, a force is exerted on the wafer to remove the adhesive layer. This is done when the wafer is very thin or has a structure related to TSV. During the removal step, there is a risk of cracks on the chip. However, since the adhesive sheet involved in one embodiment of the present invention has appropriately controlled the thickness of the adhesive layer, the possibility of chip cracking is appropriately reduced during this removal step. That is, the one embodiment of the present invention The adhesive sheet according to the embodiment has excellent pick-up properties.

When the first laminated body has an additional layer, through this lifting process, the wafer separated from the adhesive sheet has a divided body of the plate-shaped component and an additional layer formed on the adjacent surface of the adhesive sheet of the divided body of the plate-shaped component. Divided body of layers. That is, during the lifting process, peeling occurs between the adhesive layer and the divided body of the additional layer, and the processed product is separated from the adhesive sheet.

When the additional layer of the divided body provided with the additional layer is a protective film, the time point at which the protective film is formed on the protective film-forming film is not limited. The additional layer of the first laminated body is a protective film forming film, and the process of forming a protective film on the protective film forming film may also be performed until the separation process is started. The additional layer provided to the divided body is a protective film-forming film, and a protective film may be formed on the divided body of the protective film-forming film included in the processed object.

The above-described embodiments are described to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. Therefore, all design modifications or equivalents falling within the technical scope of each element described in the above-described embodiments are covered. All should still fall within the scope of the patent of this invention. (Example)

Hereinafter, the present invention will be further explained in detail through examples and the like, but the scope of the present invention is not limited by these examples and the like.

[Example 1] (1) Production of base material Using a small T-shaped extruder (manufactured by Toyo Seiki Seisaku-sho, Ltd., "Laboplastomill."), a resin composition made of randomly copolymerized polypropylene resin is extruded to produce one side (equivalent to adhesive processing The arithmetic surface roughness Ra of the other side (corresponding to the laser incident surface) is 0.03 μm, and the film is used as the base material. In addition, the surface roughness of the base material was measured using a surface roughness measuring machine ("SV-3000" manufactured by Mitutoyo Corporation).

(2) Preparation of adhesive composition 62 parts by mass of butyl acrylate, 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate (HEA) were copolymerized to obtain a copolymer (glass transition temperature Tg-34°C ), react 80 mol% of methacryloxyethyl isocyanate (MOI) with the HEA of the copolymer to obtain an acrylic polymer (weight average molecular weight 500,000) having an energy ray polymerizable group. 3.0 parts by mass of a photopolymerization initiator (manufactured by BASF, "Iragacure 184", concentration: 100%) and an isocyanate compound (manufactured by Toyo Ink Co., Ltd.) were added to 100 parts by mass of the acrylic polymer. , "BHS-8515") 1.0 parts by mass was mixed to obtain an adhesive composition diluted with a solvent.

(3) Production of adhesive sheets The above-mentioned adhesive composition is coated on the peeling surface of the peeling sheet, and the obtained coating film is subjected to an environment of 80°C for 1 minute to obtain a peeling sheet and an adhesive layer (measured The thickness is 10 μm). The adhesive layer-side surface of the above-mentioned laminate is adhered to the adhesive-processed surface of the aforementioned base material, and the peeling sheet is peeled off on the adhesive layer-side surface to obtain a state in which more layers are laminated to the base material and the adhesive layer. The adhesive sheet formed by the agent layer.

[Example 2] Except that the thickness of the adhesive layer was set to 5 μm, the rest was the same as in Example 1, and an adhesive sheet was obtained in a state where the release sheet was laminated on the surface on the adhesive layer side.

[Example 3] Except for the following modifications, the same procedure as in Example 1 was performed, and an adhesive sheet was obtained in a state where a release sheet was laminated on the surface on the adhesive layer side. (Change content): Change the molding conditions of the base material. The arithmetic surface roughness Ra of the adhesive processed surface of the base material is set to 0.16 μm, and the arithmetic surface roughness Ra of the laser incident surface is set to 0.03 μm.

[Comparative example 1] Except that the thickness of the adhesive layer was set to 15 μm, the rest was the same as in Example 3, and an adhesive sheet was obtained in a state where the release sheet was laminated on the adhesive layer.

[Comparative example 2] Except for the following modifications 1 and 2, the same procedure as in Example 1 was carried out, and an adhesive sheet was obtained in a state where a release sheet was laminated on the surface on the adhesive layer side. (Change content 1): Change the molding conditions of the base material. The arithmetic surface roughness Ra of the adhesive processed surface of the base material is set to 1.3 μm, and the arithmetic surface roughness Ra of the laser incident surface is set to 0.04 μm. (Change 2): The thickness of the adhesive layer is set to 15 μm.

[Comparative example 3] Except that the thickness of the adhesive layer was set to 10 μm, the rest was the same as Comparative Example 2, and an adhesive sheet was obtained in a state where the release sheet was laminated on the surface on the adhesive layer side.

[Comparative Example 4] Except for the following changes, the same procedure as in Example 1 was carried out, and an adhesive sheet was obtained in a state where a release sheet was laminated on the surface on the adhesive layer side. (Change content): Change the molding conditions of the base material. The arithmetic surface roughness Ra of the adhesive processed surface of the base material is set to 0.04μm, and the arithmetic surface roughness Ra of the laser incident surface is set to 1.3μm.

[Test Example 1] <Measurement of Haze> From the adhesive sheets produced in Examples and Comparative Examples, the peeling sheet was removed and cut into appropriate sizes. The haze of the obtained test pieces was measured using HAZE METER (Nippon Denshoku Industries Co.) based on JIS K7136:2000. , Ltd., "NDH-5000") measurement, the light incident on the base material side surface of the adhesive sheet was measured, and the results are shown in Table 1.

[Test Example 2] <Observation of defects> From the adhesive sheets produced in Examples and Comparative Examples, after removing the peeling sheet, an arbitrary 100 mm × 100 mm range on the adhesive layer side surface of each adhesive sheet was used as an observation range. For each of these observation ranges, Observe with an optical microscope and evaluate based on the degree of existence of defects based on the following criteria. The results are shown in Table 1. A: No defects were found within the observation range. B: Less than 5 defects are found within the observation range. C: Less than 6 defects are found within the observation range.

〔Test example 3〕＜Evaluation of retractability＞ The adhesive sheets produced in the Examples and Comparative Examples were cut into circles in plan view, and after removing the peeling sheets, they were bonded to the polysiloxane wafer (thickness: 100 μm) and the ring frame. The adhesive layer of the piece.

A laser irradiation instrument is used to scan and irradiate the wafer along the set cutting line with a concentrated laser on the opposite surface of the adhesive layer of the polysiloxane wafer and between the adhesive sheets. An 8mm×8mm wafer is formed internally. After all the planned cutting lines are irradiated with laser, use a stretching instrument to pull out the 10mm adhesive sheet at a speed of 10mm/second, so that the area on the adhesive layer side of the adhesive sheet where the polysiloxane wafer is adhered moves toward The main surface extends in the inner and outer directions.

In this state, the adhesive sheet is irradiated with ultraviolet rays according to the following conditions. Illuminance: 220mW/cm ² Light quantity: 190mJ/cm ²

Next, a Push Pull Guage (pushing jig: 1 (Pin)) manufactured by Aikoh Engineering Co., Ltd. was used to measure the load during lifting. The load required for jacking is measured. Based on this measured value, the jacking performance is evaluated according to the following standards. The results are shown in Table 1. A: Below 1.7N B: Larger than 1.7N

[Table 1] Ra of base material (μm) Thickness of adhesive layer (μm) Haze (%) Observation of flaws Preferability Adhesive processed surface Laser incident surface Example 1 0.03 0.03 10 1.39 A A Example 2 0.03 0.03 5 1.37 A A Example 3 0.16 0.03 10 3.28 B A Comparative example 1 0.16 0.03 15 3.17 A B Comparative example 2 1.3 0.04 15 8.07 B B Comparative example 3 1.3 0.04 10 8.30 C Not measured Comparative example 4 0.04 1.3 10 87.60 A Not measured

It can be seen from Table 1 that the adhesive sheet of the embodiment that meets the conditions of the present invention has low haze, is difficult to produce defects, and has excellent pick-up properties, and is an ideal laser cutting sheet. (Industrial availability)

The adhesive sheet according to the present invention is suitable for use as a laser cutting sheet.

without.

without.

Claims (7)

An adhesive sheet, which is formed by irradiating a plate-shaped component with laser light to form a modified portion, and is used to divide the above-mentioned plate-shaped component into wafers. It is characterized in that: it has a base material and one side of the base material is provided with The adhesive layer; the above-mentioned base material has an arithmetic mean roughness Ra of 0.01 μm or more and 0.2 μm or less as specified in JIS B0601:2013 (ISO 4287:1997) for the above-mentioned one side and the two sides opposite to the above-mentioned one side. ; The thickness of the above-mentioned adhesive layer is 2 μm or more and 12 μm or less; the above-mentioned adhesive layer contains an acrylic polymer having an energy ray polymerizable group, and the glass transition temperature Tg of the above-mentioned acrylic polymer is between -40°C and - 10°C or lower; the above-mentioned acrylic polymer contains structural units derived from methyl methacrylate, and the mass ratio of methyl methacrylate to the total monomers provided in the above-mentioned acrylic polymer is 7 mass % or more and 20 mass % or less . An adhesive sheet, which is formed by irradiating a plate-shaped component with laser light to form a modified portion, and is used to divide the above-mentioned plate-shaped component into wafers. It is characterized in that: it has a base material and one side of the base material is provided with The adhesive layer; the above-mentioned base material contains random copolymerized polypropylene; the above-mentioned base material has an arithmetic mean roughness specified in JIS B0601: 2013 (ISO 4287: 1997) for the above-mentioned side and the two sides opposite to the above-mentioned side. Ra series is above 0.01μm and below 0.2μm; The thickness of the above-mentioned adhesive layer is 2 μm or more and 12 μm or less; the above-mentioned adhesive layer contains an acrylic polymer, and the glass transition temperature Tg of the above-mentioned acrylic polymer is between -40°C and -10°C; the above-mentioned acrylic polymerization The product contains a structural unit derived from methyl methacrylate, and the mass ratio of methyl methacrylate to the total monomers provided for the acrylic polymer is 7% by mass or more and 20% by mass or less. For the adhesive sheet in claim 1 or 2, the haze of the adhesive sheet specified in JIS K7136:2000 (ISO 14782:1999) is 0.01% or more and 10% or less when the base material side is the incident side. . In the adhesive sheet of claim 2, the acrylic polymer has an energy ray polymerizable group. Such as the adhesive sheet of claim 1, the above-mentioned base material contains polyolefin material. For example, in the adhesive sheet of claim 5, the above-mentioned polyolefin material is random copolymerized polypropylene. A method of manufacturing a processed object, including: pasting the surface of the adhesive sheet of any one of claims 1 to 6 closer to the adhesive layer than the base material to one side of an adhesive body including a plate-shaped component. Surface, the bonding process of obtaining the first laminated body having the above-mentioned adhesive sheet and the above-mentioned plate-shaped component; by extending the above-mentioned base material having the above-mentioned first laminated body, dividing the above-mentioned plate-shaped component on the above-mentioned adhesive sheet, obtaining A dividing process in which a plurality of wafers of the divided body of the plate-shaped component are arranged on the above-mentioned adhesive sheet to form a second laminated body; and the above-mentioned plurality of wafers having the above-mentioned second laminated body are separated from the above-mentioned adhesive sheet respectively, and the above-mentioned The extraction process of wafers as processed objects; it is characterized by: Before the above-mentioned dividing process is started, the modified portion forming process is to irradiate the laser light to focus on the focus set inside the above-mentioned plate-shaped component, and form the modified portion inside the above-mentioned plate-shaped component.