TW202014490A - Adhesive sheet, and method for manufacturing processed article - Google Patents

Abstract

An adhesive sheet for use in the manufacture of chips by irradiating a plate-like member with laser light to form modified portions in the plate-like member and then dividing the plate-like member, said adhesive sheet comprising a base member and an adhesive agent layer arranged on one surface of the base member, wherein each of one surface of the base member and a surface opposed to said one surface of the base member has an arithmetic average roughness Ra as defined in JIS B0601:2013 (ISO 4287:1997) of 0.01 to 0.2 [mu]m inclusive, and the adhesive agent layer has a thickness of 2 to 12 [mu]m inclusive. The adhesive sheet rarely has defects and can exhibit excellent pickup performance when used in a dicing process with laser light.

Description

Adhesive sheet and method for manufacturing processed products

The invention relates to a method for manufacturing an adhesive sheet and a processed product; in particular, it relates to an adhesive sheet irradiated with laser light on a plate-shaped component to form a modified portion for forming the plate-shaped component into pieces to obtain a wafer-shaped processed product , And a method for manufacturing processed products such as wafers by using the above adhesive sheet.

After forming a circuit on the surface of the semiconductor wafer, a grinding process is performed on the back of the wafer, a back grinding process to adjust the thickness of the wafer, and a dicing process to slice the wafer into a desired wafer size.

Recently, as the size of electronic equipment casings has shrunk or the demand for semiconductor devices using multi-layered chips has increased, the semiconductor chips that constitute the component are continuously thinning. Therefore, for wafers with an original thickness of about 350 μm, thinning is required To 50 ~ 100μm or below this thickness.

The thinned component wafers become thinner, and the risk of damage during processing and handling increases. If such a thin wafer is cut by a high-speed rotating dicing blade, especially on the back surface of a semiconductor wafer, chip cracking and the like may occur, which significantly reduces the bending strength of the wafer.

Therefore, the patent literature discloses that the laser light is irradiated to the inside of the semiconductor wafer, a modified portion is selected to form a cutting line and a dicing line is formed, and the semiconductor wafer is cut based on the modified portion. 1). According to the invisible dicing method, after irradiating the inside of the semiconductor wafer with laser light to form a modified portion, the thin semiconductor wafer is adhered to an adhesive sheet (dicing sheet) composed of a base material and an adhesive layer, and the dicing sheet After extending and dividing (cutting) the semiconductor wafer along the dicing line, the semiconductor wafer can be produced with good yield. In addition, it is also disclosed that after the semiconductor wafer is pasted on the dicing sheet, the modified portion is formed by irradiating with laser light. By using such a process to form the modified portion, since there is no need to go through the process of attaching the dicing tape to the wafer that has become weak, the risk of damage to the wafer that has become weak can be reduced. In such a case, since the laser system is generally irradiated on the surface of the wafer where no circuit is formed, it is necessary to irradiate the laser through the dicing sheet.

As in the above dicing process, as a processing method, some cases require the use of lasers, and in the dicing process, lasers are also used as tools for accurately calibrating plate-like components such as semiconductor wafers. In the same cutting process as in these cases, when using laser light, the adhesive sheet used (this adhesive sheet is referred to as "laser cutting sheet" in the patent specification of the present invention) during the use process, this laser When the laser cutting blade passes through the laser, the laser light must have excellent penetrability.

To meet such requirements, for example, Patent Document 2 discloses that as a laser dicing sheet formed of a substrate and an adhesive layer formed on one side, the total light transmittance in the wavelength range of 300 to 400 nm is 60% or more The haze is less than 20%, the width of the optical comb is 0.25mm, and the penetration sharpness is more than 30. [Prior Technical Literature] [Patent Literature]

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

(Problems to be solved by the invention)

In Patent Document 2, as the above-mentioned laser dicing sheet, the centerline average roughness Ra of one side of the base material is larger than the centerline average roughness Ra of the other side surface, so that the centerline average roughness Ra is larger Adhesive layer is formed, and the surface with the centerline average roughness Ra of 0.3 to 0.7 μm is used as the adhesive layer forming surface, and the centerline average roughness Ra of the opposite surface of the substrate is 0.14 μm laser Cutting sheet (patent document 2 example).

This laser dicing sheet has a smooth surface on the opposite side of the adhesive layer forming surface of the substrate on the laser incident side, which can prevent the laser light on the surface of the substrate from being scattered and effectively use the laser light.

However, the thickness of semiconductor wafers and other processed products manufactured on plate-like components such as semiconductor wafers using laser dicing blades tends to become thinner. In addition, the recent implementation of high-density mounting has sometimes caused A polysilicon wafer is used to replace the substrate, and a silicon (Si) through electrode (TSV, Through-Silicon Via) laminated chip is used on the substrate. In the same way, when the processed object is thin or the processed object has a structure related to TSV, the adhesive layer of the laser dicing sheet can be easily peeled off from the processed object attached to the adhesive layer (excellent pickability) ) Is better.

On the other hand, in the laser dicing sheet described in Patent Document 2, there may be 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 dicing sheet. Defects may cause the plate components of the laser incident for the processing of the plate components to reach optical unevenness.

The present invention is an adhesive sheet used in the case of using laser light in a cutting process, the purpose of which is to provide an adhesive sheet that is difficult to produce defects and has excellent pick-up properties, and to provide such an adhesive sheet for a plate-shaped component A method of manufacturing processed products. [Technical means to solve the problem]

In order to achieve the above object, the present inventors have made intensive studies, and by setting the thickness of the adhesive layer to 2 μm or more and 12 μm or less, and the arithmetic mean roughness Ra on both sides of the base material to 0.2 μm or less, stable To reduce the possibility of defects, and at the same time, it has a new knowledge of the adhesive sheet with superior picking. The present invention has been completed on the basis of the above new knowledge, and the contents are as follows.

(1) An adhesive sheet, which is formed by irradiating laser light on a plate-shaped component to form a modified portion for dividing the plate-shaped component into a wafer, and is characterized in that it has a substrate and a side of the substrate The adhesive layer provided on the surface, the above-mentioned substrate with respect to the above-mentioned one side and the two sides opposite to the above-mentioned side, the arithmetic average roughness Ra specified in JIS B0601:2013 (ISO 4287:1997) is 0.01 μm or more , 0.2 μm or less, the thickness of the adhesive layer is 2 μm or more and 12 μm or less.

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

(3) The adhesive sheet according to the above item (1) or (2), wherein the adhesive layer contains an acrylic polymer, and the glass transition temperature Tg of the acrylic polymer is −40° C. or higher, − Below 10℃.

(4) The adhesive sheet according to the above item (3), wherein the acrylic polymer includes a structural unit derived from methyl methacrylate, and methyl methacrylate is added to the entire monomers given to the acrylic polymer The mass ratio is 5% by mass or more and 20% by 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-based material.

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

(8) The adhesive sheet according to the above item (7), wherein the roller used in the roller pressing has a surface composed of a metal material.

(9) A method of manufacturing a processed product, comprising: adhering the surface of the adhesive sheet according to any one of the above items (1) to (8) closer to the adhesive layer than the substrate One side surface of the adhesive body including the plate-like component, to obtain a bonding process of the first laminate having the adhesive sheet and the plate-like component; by stretching the base material having the first laminate, the bonding is divided The plate-shaped component on the sheet, obtaining a plurality of wafers having a divided body of the plate-shaped component, a division process of a second laminated body formed on the adhesive sheet; and combining the plurality of wafers of the second laminated body Separation of the portions from the adhesive sheet, and the top picking process obtained by using the wafer as a processed object; characterized in that, until the start of the division process, the laser light is irradiated to focus on the focus set inside the plate-like assembly, A reforming part forming process for forming a reforming part inside the plate-shaped component.

(10) The method for manufacturing a processed product according to the above item (9), wherein the first laminate provided in the division process has an additional layer between the adhesive layer and the plate-like component, The dividing process divides the additional layer at the same time, and in the top picking process, the wafer separated from the adhesive sheet has the divided body of the plate-like component, and the surface of the divided body of the plate-like component formed on the surface adjacent to the adhesive sheet The division of the above additional layer.

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

(12) The method for manufacturing a processed product according to the above item (11), until the division process is started, a protective film forming process including the protective layer for forming the first layered body by forming a thin film with a protective film.

(13) The method for manufacturing a processed product according to the above item (10), wherein the additional layer has a crystal grain bonding layer. [Efficacy of invention]

The present invention provides an adhesive sheet that is difficult to produce defects and has superior pick-up properties. In addition, by using such an adhesive sheet, a processed product can be stably manufactured on a plate-shaped component.

The embodiments of the present invention will be described in detail below.

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

(1) Base material The substrate of the adhesive sheet according to one embodiment of the present invention has the opposite side of the adhesive layer (referred to as "adhesive processing surface" in the patent specification of the present invention) and the opposite side of the adhesive processing surface The two surfaces (referred to as "laser incidence surface" in the patent specification of the present invention), the arithmetic mean roughness Ra (the "arithmetic mean roughness" not specifically noted below) specified in IS B0601:2013 (ISO 4287:1997) "Ra" means this)) is less than 0.2μm. The arithmetic average roughness Ra of these planes is 0.2 μm or less, and it is difficult to observe defects in the plan view of the adhesive sheet. Therefore, the laser light incident on the substrate side of the adhesive sheet easily reaches the adhesive sheet uniformly In the case of pasted plate-shaped components, when this kind of laser light reaches the plate-shaped components unevenly, for example, there is a part in the plate-shaped component where the modified part is not properly formed, and the number of occurrences of the plate-shaped component from this part There is a possibility that the fragmentation cannot be performed properly. From the viewpoint of improving the uniformity of the incident laser light described above, the arithmetic mean roughness Ra is preferably 0.18 μm or less, preferably 0.16 μm or less, for both the adhesive processed surface and the laser incident surface. The best series is 0.14 μm or less, and the particularly good series is 0.12 μm or less. From the viewpoint of obtaining an adhesive sheet that is difficult to cause planar visual defects, there is no limit to the lower limit of the arithmetic mean roughness Ra for the processed surface of the adhesive. 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 processed surface and the laser incident surface.

The constituent material of the base material according to one embodiment of the present invention satisfies the relevant conditions for the above arithmetic average roughness Ra, and can be used as a base material for laser cutting pieces, that is, as long as the laser light at a desired wavelength can The penetration rate in the practical range is not particularly limited, even if it extends in the in-plane direction or protrudes in the local thickness direction, and can meet the requirement of being difficult to break. The base material according to one embodiment of the present invention is usually composed of a thin film made mainly of a resin material. The film can be a single layer or a laminate.

Specific examples of resin materials included in this film include: random copolymer polypropylene, block copolymer polypropylene and other polypropylene; low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density Polyethylenes such as polyethylene (HDPE); ethylene/vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, ethylene-norbornene copolymers and other ethylene-based copolymers ; Cycloolefin polymer (COP) polybutene, polybutadiene, polymethylpentene and other polyolefin-based materials such as norbornene resin; polyvinyl chloride-based materials such as polyvinyl chloride and vinyl chloride copolymer; poly pairs Polyester materials such as ethylene phthalate and poly(butylene terephthalate); polyurethane materials; polyimide materials; ionic polymer resin materials; homopolymers of alkyl (meth)acrylates Polyacrylic materials such as polymers and copolymers of alkyl (meth)acrylates; polystyrene materials; polycarbonate materials; fluororesin materials; and hydrides and denatured materials of these resin materials Resin materials as the main material. The resin material may also be a bridging material of the above materials and bridging agent. In addition, "(meth)acrylic acid" in the patent specification of the present invention means both acrylic acid and methacrylic acid, and other similar terms are also the same. The resin material given to the above-mentioned base material may be one kind alone, or a mixture of two kinds or more. From the viewpoints of high laser penetration, extension in the in-plane direction, ease of local deformation in the thickness direction, and low environmental load, it is preferred that the substrate according to one embodiment of the present invention contains a polyolefin-based material Among the polyolefin materials, polypropylene containing random copolymer polypropylene and the like is preferred.

In the case where the resin-based material included in the base material is a polyolefin-based material, generally, the control of the arithmetic surface roughness Ra of both sides of the base material can be formed by using two rollers to pressurize the roller through which the base material is embedded. By adjusting the surface materials constituting the rollers and the roughness of the surface, the arithmetic surface roughness Ra of both sides of the base material is set. The surface of these rollers has always been formed of metal on one side and an elastic material like rubber on the other side. Therefore, the arithmetic surface roughness Ra of the surface contacting the base material of the roller formed of a metal surface can be It is relatively easy to perform at a low value, but the arithmetic surface roughness Ra of the surface of the base material contacting the roller formed of an elastic material is difficult to perform at a low value. Here, as 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, for both sides of the roll required for roll pressing, metal is used. The formation of the surface is better. However, in this case, the relative arrangement of the rollers on both sides and the substrate needs to be controlled more strictly than when the surface of one roller is formed of an elastic material. The resin-based materials included in the substrate are polyvinyl chlorides. In the case of a material, since the substrate can be manufactured by inflation molding, the arithmetic surface roughness Ra on both sides of the substrate can be easily set to a low value. However, since the polyvinyl chloride-based material contains halogen elements, it is better not to use it as a base material under the demand of reducing the environmental load.

The base material is a film that uses the above-mentioned resin-based material as a main material, and may also contain various additives such as colorants, flame retardants, plasticizers, antistatic agents, lubricants, and fillers. As for the colorant, pigments such as titanium dioxide and carbon black or various dyes can be exemplified. In addition, as for the filler, for example, organic materials such as melamine resin, inorganic materials such as fumed silica, and metal materials such as nickel steel particles. Although the content of this additive is not particularly limited, it must be fixed within the range that can perform the function required by the substrate, especially the function of penetrating the laser, without losing the required smoothness and flexibility.

In order to harden the adhesive layer, when ultraviolet rays are used as the energy ray to be irradiated, it is preferable that the base material has ultraviolet permeability. In addition, when an electron beam is used as an energy ray, it is preferable that the base material has electron beam penetration.

In terms of the thickness of the base material, the adhesive sheet is not particularly limited as long as it can properly function in each of the aforementioned processes, and it is preferably in the range of 20 to 450 μm, more preferably in the range of 25 to 200 μm The range of the ultra good series is between 50 and 150 μm.

The Young's modulus of the substrate is preferably 50 to 500 MPa. By setting the Young's modulus within this range, good ductility can be maintained, and at the same time, the mechanical strength of the substrate can be improved, so that the process properties when forming the adhesive layer are good. For example, when a polyolefin-based resin film as a base material is placed in a coating machine, it is possible to prevent the base material from being stretched unexpectedly when tension is applied. It is difficult to block from the above-mentioned Young's modulus. In addition, the mechanical strength is improved. From the viewpoint of relatively good expandability, it is preferably 60 to 450 MPa, more preferably 100 to 420 MPa, and particularly preferably 150 to 300 MPa.

(2) Adhesive layer The thickness of the adhesive layer having the adhesive sheet according to one embodiment of the present invention is 2 μm or more and 12 μm or less. By the thickness of the adhesive layer being in the above range and the arithmetic mean roughness Ra of both sides of the base material being in the aforementioned range, it is possible to obtain defects that are difficult to produce from a plane view and have superior pick-up properties Adhesive sheet. From the viewpoint of relatively stably reducing the possibility of the occurrence of the defects, the thickness of the adhesive layer is preferably 3 μm or more, and more preferably 4 μm or more. From the viewpoint of achieving a more stable adhesive sheet with superior pick-up, 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 for forming the adhesive layer having the adhesive sheet according to one embodiment of the present invention is not limited, and examples of the adhesive included in this adhesive composition include: Adhesives such as rubber, acrylic, polysiloxane, and polyvinyl ether. Hereinafter, a case where the adhesive composition for forming the adhesive layer contains an acrylic adhesive will be described as an example. Due to the excellent transparency of acrylic adhesives, it is easy to penetrate laser light.

Acrylic adhesives contain acrylic polymers. The acrylic polymer is a polymer that contains a structural unit based on an acrylic compound as a unit that constitutes the skeleton. The acrylic polymer may be a homopolymer formed by polymerization of one kind of monomer, or a copolymer formed by polymerization of multiple kinds of monomers. From the viewpoint of easy control of polymer physical properties and chemical properties, acrylic polymer copolymers are preferred.

The glass transition temperature Tg of the acrylic polymer is preferably -40°C or higher and -10°C or lower. By including an acrylic polymer with a glass transition temperature Tg of -40°C or higher in the adhesive composition, it becomes possible to reduce the adhesiveness of the adhesive layer and further improve the topping property. From the viewpoint of more stably obtaining such an effect of improving top picking, the glass transition temperature Tg of the acrylic polymer is preferably -35°C or higher. After the wafer is divided into wafers, the acrylic polymer preferably has a glass transition temperature Tg of -20°C or lower from the viewpoint of easily maintaining and maintaining wafer performance.

The weight average molecular weight (Mw) of the acrylic polymer is not limited, but it is usually preferably 100,000 to 2 million, and more preferably 300,000 to 1.5 million. In addition, the molecular weight distribution (Mw/Mn, Mn coefficient average molecular weight) is also not limited, but it is usually preferably 1.0 to 10, and more preferably 1.0 to 3.0.

The specific type of monomers imparted to the acrylic polymer is not limited, and examples of such monomers include (meth)acrylic acid, (meth)acrylate, and acrylonitrile. As specific examples of (meth)acrylates, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, (meth) 2-ethylhexyl acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, pentadecyl (meth) acrylate, octadecyl (meth) acrylate, etc. alkyl carbon number system 1～ 18 Alkyl (meth)acrylate; cycloalkyl (meth)acrylate, benzyl (meth)acrylate, isobornyl acrylate, dicyclopentyl acrylate, dicyclopentenyl acrylate , Dicyclopentenyl hydroxyethyl acrylate, amide imido acrylate and other (meth)acrylates with a cyclic skeleton; 2-(meth)acrylic acid hydroxyethyl, 2-(meth)acrylic acid hydroxy (Meth)acrylates having hydroxyl groups such as propyl ester; (meth)acrylates having epoxy resin groups such as glycidyl methacrylate and glycidyl acrylate;

From the viewpoint of increasing the glass transition temperature Tg of the acrylic polymer, 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 methyl methacrylate for the entire monomers imparted 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 also be a copolymer containing vinyl acetate, styrene, vinyl acetate, etc. as monomers.

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

In the case where the acrylic polymer contains an energy line polymerizable group, by irradiating the energy line with the adhesive layer, it is easier to obtain an adhesion that can reduce the adhesion to the adherend and has superior ejection properties sheet. As the energy ray polymerizable group, a group having a polymerizable double bond can be exemplified. The preparation method of the acrylic polymer having an energy ray polymerizable group is not limited. As an example of such a preparation method, for an acrylic polymer having a functional group containing an active hydrogen group such as a hydroxyl group, a carboxylic acid group, an amine group, etc. , A functional group capable of reacting with the aforementioned functional group such as an isocyanate group, and a reactant of a substance having an energy ray polymerizable group (specifically, (meth)acrylic acid ethoxy isocyanate). In addition, through this adjustment method for acrylic adhesives, in the case of containing an acrylic polymer containing an energy ray polymerizable group, the glass transition temperature Tg of the acrylic polymer mentioned above means that The functional group reacts with the functional group, and the Tg before the reaction of the substance having the energy ray polymerizable group.

When the acrylic polymer has a reactive functional group, the reactive functional group reacts with the bridging agent to adjust the cohesiveness of the adhesive layer to suppress the occurrence of residues on the adherend after the peeling of the adhesive sheet, or to cause adhesion The adhesiveness of the agent layer is low, and it is easier to improve the ejection ability. The combination of the reactive functional group and the bridging agent is not limited, and examples of the reactive functional group include a group having active hydrogen such as a hydroxyl group, a carboxylic acid group, and an amine group. Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy resin-based cross-linking agents, aziridine-based cross-linking agents, and metal clamp-type cross-linking agents. The isocyanate-based bridging agent contains at least a polyisocyanate compound containing multiple isocyanate groups. Examples of polyisocyanate compounds include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; dicyclohexylmethane-4,4 '-Diisocyanate, dicycloheptane triisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, methyl cyclohexyl diisocyanate, hydrogenated xylene Alicyclic isocyanate compounds such as diisocyanate; cyclohexane diisocyanate, trimethylcyclohexane diisocyanate, amine acid diisocyanate and other non-cyclic aliphatic isocyanates Acid salt, the biuret and triisocyanate, compounds with isocyanate groups, ethylene glycol, trimethylolpropane, grate oil, etc. and non-aromatic low molecular active hydrogen compounds Adducts and other denatured products.

Examples of epoxy resin bridging agents 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 group, glycidylamine, etc.

Examples of aziridine bridging agents include diphenylmethane-4,4'-bis(1-azacyclopropanecarboxamide), trimethylolpropane tri-β-aziridinepropionic acid, tetrakis Methylmethane tri-β-aziridinepropionic acid, toluene-2,4-bis(1-azacyclopropanecarboxamide), trimelamine, bisisophthalamide-1-(2-methylazacyclo Propane), tri-1-(2-methylazacyclopropane)phosphine, trimethylolpropane tri-β-(2-methylazacyclopropane) propionate, etc.

Among metal clamp compounds, metal atoms include aluminum, zirconium, titanium, zinc, iron, tin, and other clamp compounds. Among these, aluminum clamp compounds are ideal because of their good performance. Examples of aluminum clamp compounds include: diisopropoxyaluminum single oil acetyl acetate, monoisopropoxyaluminum double oil acetoacetate, monoisopropoxyaluminum monooleate single oil Acetate Acetate, Diisopropoxyaluminum Monolauryl Acetate, Diisopropoxyaluminum Monostearate Acetyl Acetate, Diisopropoxyaluminum Monoisostearate Acetate, etc.

When the adhesive composition contains an acrylic polymer, the adhesive composition may contain components other than the acrylic polymer. For such a material, an energy ray polymerizable compound can be cited as an example. The energy ray polymerizable compound is a compound that is polymerized by irradiation with energy rays such as ultraviolet rays, electron beams, etc. Examples of the energy ray polymerizable compound include low molecular weight compounds (monofunctional, polyfunctional monomers and Polymer) as an example, specific examples include: trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, neopentyl alcohol triacrylate, pentaerythritol monohydroxypentyl acrylate, pentaerythritol hexyl acrylate, or 1,4-Butene ethylene glycol diacrylate, 1,6-hexanediol diacrylate, dicyclopentadiene dimethoxy diacrylate, isobornyl acrylate, etc. containing cyclic aliphatic skeleton Acrylic esters; polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy resin modified acrylate, polyether acrylate and other acrylate compounds. Such a compound has at least one polymerizable double bond in the molecule, and usually has a molecular weight of 100 to 30,000, preferably about 300 to 10,000. The adhesive composition is an acrylic adhesive containing 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 content of the low-molecular-weight compound having an energy ray polymerizable group in the adhesive composition is large, there is a tendency for the propensity to decrease. Therefore, the adhesive composition is an acrylic adhesive. By containing an acrylic polymer containing an energy-ray polymerizable group, the amount of low-molecular-weight compounds having an energy-ray polymerizable group can be reduced, and the ejection property can be further improved. 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 and contains 0 to 15 parts by mass with respect to 100 parts by mass of the acrylic polymer. Servings are better, containing 0 to 10 parts by mass.

When the adhesive composition contains an acrylic polymer containing an energy line polymerizable group or an energy line polymerizable compound, it is also preferable to contain a photopolymerization initiator. As a photopolymerization initiator, for example: benzoin Compounds, acetophenone compounds, acetylphosphine 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 acetyl, β-chloroanthraquinone, 2,4,6-trimethylbenzyl-diphenyl-phosphine Oxides, etc. By using a photopolymerization initiator and using ultraviolet rays as an energy ray, it can be performed with a small amount of irradiation time and irradiation amount.

Examples of the energy ray for reacting the energy ray polymerizable group and the energy ray polymerizable compound include free radiation, that is, X-rays, ultraviolet rays, and electron beams. Among these, it is better that it is relatively easy to prepare the ultraviolet rays of the irradiation equipment.

As the free radiation, when ultraviolet rays are used, from the viewpoint of ease of handling, near ultraviolet rays including ultraviolet rays having a wavelength of about 200 to 380 nm may be used. The amount of ultraviolet light can be appropriately selected according to the type of the energy ray polymerizable group and the energy ray polymerizable compound contained in the adhesive layer, and the thickness of the adhesive layer, usually 50 to 500 mJ/cm ² about, preferred system 100 ~ 450mJ / cm ^2, more preferably based 150 ~ 400mJ / cm ^2. Further, an ultraviolet line illumination generally 50 ~ 500mW / cm ² or so, preferably based 100 ~ 450mW / cm ^2, more preferably based 150 ~ 400mW / cm ^2. The ultraviolet source is not particularly limited, for example, a high-pressure mercury lamp, a metal halogen lamp, etc. can be used.

In the case of using electron beams as free radiation, the acceleration voltage may be appropriately selected according to the type of energy ray polymerizable group, energy ray polymerizable compound contained in the adhesive layer, and the thickness of the adhesive layer, usually accelerated The voltage system is preferably about 10 to 1000 kV. In addition, the irradiation dose may be set within a range in which the reaction of 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 include Cockcroft-Walton accelerator, Van de Graaff accelerator, resonant transformer type accelerator, insulated core transformer type accelerator , Or various electron beam accelerators such as linear type, high frequency and high pressure (Dynamitron) type accelerator, high frequency type accelerator, etc.

(3) Optical characteristics The adhesive sheet according to one embodiment of the present invention has a haze specified in JIS K7136:2000 (ISO 14782:1999), which is 0.01 when the surface adjacent to the base material is the incident surface compared to the adhesive layer % Is more than 10%. When the haze is below 10%, the laser light incident on the adhesive sheet can be effectively used. From the viewpoint of more stable and effective utilization of the laser light incident on the adhesive sheet, the haze is preferably 5% or less, more preferably 2.5% or less; from the effective use of the laser light incident on the adhesive sheet From a viewpoint, there is no lower limit for the above-mentioned haze; and from the viewpoint of improving manufacturing stability, etc., the above-mentioned haze is preferably about 0.01% or more.

The adhesive sheet according to one embodiment of the present invention has a total light transmittance stipulated in JIS K7375:2000. Compared to the adhesive layer, when the surface adjacent to the substrate is used as the incident surface, it is preferably 85% or more. . Through the total light transmittance of 85% or more, the laser light incident on the adhesive sheet can be effectively utilized. From the viewpoint of effectively utilizing the laser light incident on the adhesive sheet, the above-mentioned total light transmittance is preferably 90% or more; from the viewpoint of effectively utilizing the laser light incident on the adhesive sheet, the above-mentioned total light transmittance is not The upper limit is set; and from the viewpoint of improving manufacturing stability, etc., the above-mentioned total light transmittance is preferably about 99.99% or less.

(4) Additional layer In the adhesive sheet according to one embodiment of the present invention, an additional layer is formed on the surface on the adhesive layer side. When the adhesive sheet is used, the plate-like component of the adhesive body of the adhesive sheet may also be pasted to the additional layer. The configuration 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 crystal 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 is formed into a thin film or a protective film, and the divided body is separated from the adhesive layer in a state where the divided body is attached to the wafer-shaped component formed by the sheet-shaped component formed into pieces. Therefore, in the case where the additional layer-based protective film is formed into a thin film, a processed product formed by depositing a protective film-forming thin film or a divided body of the protective film on one side surface of the wafer-shaped package can be obtained.

In the case where the additional layer is a die-bonding layer, the wafer-like component formed by slicing the plate-like component is separated from the adhesive layer in a state where the divided body of the die-bonding layer is attached. Therefore, in the case where the additional layer is a crystal grain bonding layer, a processed article formed by dividing the crystal grain bonding layer on one side surface of the wafer-shaped device can be obtained.

(5) Peel off piece The adhesive sheet according to one embodiment of the present invention has a purpose of protecting the adhesive layer or the additional layer during the period from when the adhesive layer or the additional layer is adhered to the plate-shaped component of the adherend, The peeling surface of the peeling sheet may be attached to the surface of the adhesive layer closer to the surface of the adhesive layer than the base material of the adhesive sheet, specifically, the surface of the adhesive layer or the surface of the additional layer. The composition of the peeling sheet is not limited. For example, a peeling agent can be coated on the 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 or polyethylene. As for the release agent, although polysiloxanes, fluorines, long-chain alkanes, etc. can be exemplified, these are preferably polysiloxanes which are inexpensive and can obtain stable performance. Instead of using a plastic film, the release sheet may be replaced with paper substrates such as cellophane, coated paper, and dowling paper, or laminated paper with a thermoplastic resin such as polyethylene laminated on the paper substrate. Although the thickness of the release sheet is not particularly limited, it 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 product can be manufactured on a plate-shaped component as described below.

(1) Pasting process First, in the adhesive sheet according to one embodiment of the present invention described above, the surface closer to the adhesive layer than the substrate, specifically the surface of the adhesive layer or the surface of the additional layer, is adhered to On one side surface of the adherend of the plate-like component, a first laminate having an adhesive sheet and a plate-like component was obtained. The plate-shaped components are not limited, for example, semiconductor wafers such as polysilicon wafers, and laminates having a structure related to TSV. The thickness of the plate-shaped component is also not limited, for example: a range of tens of μm to hundreds of μm.

The first layered body may have an additional layer. Examples of the additional layer include: a protective film formed on the protective film, a protective film formed on the protective film formed film, and a crystal grain bonding layer. As a part of the adhesive sheet, the additional layer can be adhered to the plate-shaped component, or an additional layer can be deposited on one side of the plate-shaped component in advance. In the latter case, the opposite surface of the plate-shaped component opposite to the additional layer serves as a side surface of the adherend including the plate-shaped component, and becomes the surface to which the adhesive sheet adheres.

(2) Split process By spreading the base material having the first laminate, and dividing the plate-like component on the adhesive sheet, a second laminate formed by disposing a plurality of wafers having the divided body of the plate-like component on the adhesive sheet is obtained. When the first laminate has an additional layer, the additional layer is also divided by extending the base material. After the division process is completed, the part of the base material that has a greater degree of extension can be shrunk by heating or other methods, which can also solve the occurrence of excessive slack to the adhesive sheet.

(3) Forming process of modified parts Until the start of the above-mentioned division process, the laser beam is irradiated to focus on the focal point set 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 and thickness of the plate-shaped component. After the above-mentioned pasting process is completed and the reforming part forming process is performed, the irradiation of the laser light to the plate-shaped component may also be formed through the adhesive sheet. Even in that case, since the adhesive sheet according to one embodiment of the present invention is difficult to produce defects in plan view, the degree of laser light irradiation varies from the defects and the vicinity, resulting in a plate-shaped component The problem that the modified part inside becomes partially inappropriate is also difficult to occur. Similarly, if the formation of the modified material in the plate-shaped component is partially inappropriate, there may be a concern that the plate-shaped component cannot be properly divided in the above-mentioned division process. If the division of the plate-like component cannot be performed properly, the possibility of the quality of the processed object lowering will increase.

(4) Top picking process By individually separating the plurality of wafers of the second laminate from the adhesive sheet, a wafer as a processed product can be obtained. The separation method is not limited. Usually, the opposite side of the opposite side of the wafer of the adhesive sheet is pushed up with a pin (Pin) or the like. By locally deforming the adhesive sheet, the adhesion of the adhesive layer to the wafer that is expected to be separated Connectivity is reduced. Next, using a collet or the like, the wafer to be separated is removed from the adhesive sheet to separate the wafer from the adhesive sheet. In this case, when ejecting the pin or pulling the wafer up from the vacuum collet, a force to remove the adhesive layer is applied to the wafer, and the wafer is thin or has a structure related to TSV. During the removal step, there is a fear of cracks on the wafer. However, since the adhesive sheet according to one embodiment of the present invention has properly controlled the thickness of the adhesive layer, when this removal step is performed, the possibility of wafer cracking is appropriately reduced, that is, one of the present invention The adhesion of the adhesive sheet according to the embodiment is excellent.

In the case where the first laminate has an additional layer, the wafer separated from the adhesive sheet through this top-drawing process has the divided body of the plate-like component and the additional surface formed on the adjacent surface of the adhesive sheet of the divided body of the plate-like component Layer division. That is, during the top picking process, peeling occurs between the adhesive layer and the divided body of the additional layer, and the processed object is separated from the adhesive sheet.

In the case where the additional layer of the divided body provided with the additional layer is a protective film, there is no limitation on the time point when the protective film is formed on the protective film forming thin film. The additional layer of the first layered body is a protective film formed into a thin film, and until the separation process is started, a thin film formed on the protective film may be formed into a protective film. The additional layer that imparts the division body to the additional layer is a protective film-forming thin film, and a protective film may be formed on the division body of the protective film-forming thin film included in the processed product.

The above-described embodiments are described for easy understanding of the present invention, but the scope of implementation of the present invention cannot be limited by this. Therefore, all design changes or equivalents within the technical scope of each element described in the above embodiments, All should still fall within the scope of this invention patent. (Example)

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

[Example 1] (1) Fabrication of substrate 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 surface roughness Ra of the surface) is 0.03 μm, and the surface roughness Ra of the other side (corresponding to the laser incidence surface) is 0.03 μm, which is used as the substrate. In addition, the surface roughness of the base material was measured using a surface roughness measuring machine (manufactured by Mitutoyo Corporation, "SV-3000").

(2) Preparation of adhesive composition 62 parts by mass of butyl acrylate and 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate (HEA) were copolymerized to the obtained copolymer (glass transition temperature Tg-34°C) ), methacryloyl oxyethyl isocyanate (MOI) was reacted with the copolymer HEA by 80 mol% to obtain an acrylic polymer having an energy ray polymerizable group (weight average molecular weight of 500,000). With respect to 100 parts by mass of the acrylic polymer, 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.) , "BHS-8515") After mixing 1.0 part by mass, an adhesive composition obtained by dilution with a solvent was obtained.

(3) Production of adhesive sheet The above adhesive composition was applied to the peeling surface of the peeling sheet, and each peeling sheet was subjected to an environment of 80°C for 1 minute by the obtained coating film to obtain a peeling sheet and an adhesive layer (measured The thickness is 10 μm). The surface of the adhesive layer on the adhesive layer side of the above-mentioned laminated body is adhered to the adhesive processing surface of the substrate described above, and the substrate and the adhesive are obtained in a state where the peeling sheet is laminated on the surface on the adhesive layer side more Adhesive sheet formed by the adhesive layer.

[Example 2] Except that the thickness of the adhesive layer was set to 5 μm, the rest were the same as in Example 1, and the 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 changes, the others are the same as in Example 1, and the adhesive sheet was obtained in a state where the release sheet was laminated on the surface on the adhesive layer side. (Contents of change): The molding conditions of the substrate were changed, and the arithmetic surface roughness Ra of the adhesive processed surface of the substrate was set to 0.16 μm, and the arithmetic surface roughness Ra of the laser incident surface was set to 0.03 μm.

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

[Comparative Example 2] Except for the following changes 1 and 2, the rest were the same as in Example 1, and the adhesive sheet was obtained in a state where the release sheet was laminated on the surface on the adhesive layer side. (Content of change 1): The molding conditions of the base material were changed, and the arithmetic surface roughness Ra of the adhesive processed surface of the base material was 1.3 μm, and the arithmetic surface roughness Ra of the laser incident surface was 0.04 μm. (Modification 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 others were the same as those in Comparative Example 2. The adhesive sheet was obtained in a state where a release sheet was laminated on the surface on the adhesive layer side.

[Comparative Example 4] Except for the following changes, the rest were the same as in Example 1, and the adhesive sheet was obtained in a state where the release sheet was laminated on the surface on the adhesive layer side. (Contents of change): The molding conditions of the substrate were changed, and the arithmetic surface roughness Ra of the adhesive processed surface of the substrate was set to 0.04 μm, and the arithmetic surface roughness Ra of the laser incident surface was set to 1.3 μm.

〔Test Example 1〕>Haze measurement> In the adhesive sheets manufactured by Examples and Comparative Examples, the peeling sheet was removed and cut to an appropriate size. The haze of the obtained test piece was based on JIS K7136:2000, using HAZE METER (Nippon Denshoku Industries Co. , Ltd., "NDH-5000") measurement, measuring light incident on the surface of the adhesive sheet on the substrate side, the results are shown in Table 1.

[Test Example 2]> Observation of Defects> In the adhesive sheets manufactured in Examples and Comparative Examples, after removing the release sheet, an arbitrary 100 mm×100 mm range of the surface of each adhesive sheet on the adhesive layer side was used as an observation range. For each of these observation ranges, Observed with an optical microscope, and evaluated according to the following criteria according to the degree of defects, the results are shown in Table 1. A: No defects were found in the observation range. B: Less than 5 defects were found in the observation range. C: Less than 6 defects were found in the observation range.

〔Test Example 3〕>Topic evaluation> Cut the adhesive sheet manufactured by the examples and the comparative examples into a circular shape in plan view, remove the peeling sheet, and adhere to the polysilicon wafer (thickness: 100 μm) and ring frame (Ring frame) The adhesive layer of the tablet.

Using a laser irradiation instrument, on the opposite side of the adhesive layer of the polysilicon wafer, between the adhesive sheets, the laser focused on the light is scanned and irradiated along the set predetermined cutting line to make the wafer An 8mm x 8mm wafer is formed inside. After irradiating all the scheduled cutting lines with laser, use a stretching device to pull the 10mm adhesive sheet at a speed of 10mm/sec, so that the silicon oxide wafer on the adhesive layer side of the adhesive sheet adheres to the block The main surface extends in and out.

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

Next, using Aikoh Engineeering Co., Ltd., Push Pull Guage (upper jig: 1 (Pin)) to measure the load during jacking. When measuring the load required for jacking, according to this measured value, the jacking property is evaluated according to the following criteria. The results are shown in Table 1. A: Below 1.7N B: greater than 1.7N

[Table 1]

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

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

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Claims (12)

An adhesive sheet is formed by irradiating laser light on a plate-shaped component to form a modified portion, which is used to divide the plate-shaped component into wafers, and is characterized in that it has a substrate and a side surface of the substrate Adhesive layer of the above-mentioned base material: For the one side surface and the two opposite surfaces of the one side surface, the arithmetic average roughness Ra specified in JIS B0601:2013 (ISO 4287:1997) is 0.01 μm or more and 0.2 μm or less The thickness of the adhesive layer is 2 μm or more and 12 μm or less; the adhesive layer contains an acrylic polymer, and the glass transition temperature Tg of the acrylic polymer is -40°C or more and -10°C or less. According to the adhesive sheet described in item 1 of the scope of the patent application, the haze specified in JIS K7136:2000 (ISO 14782:1999) is 0.01% or more when the base material side is the incident side. Below 10%. According to the adhesive sheet described in item 1 of the patent application scope, the acrylic polymer contains structural units derived from methyl methacrylate, and the mass ratio of methyl methacrylate to the entire monomers imparted to the acrylic polymer It is 5% by mass or more and 20% by mass or less. According to the adhesive sheet described in item 1 of the patent application scope, the acrylic polymer has an energy ray polymerizable group. According to the adhesive sheet described in item 1 of the patent application scope, the above-mentioned substrate contains a polyolefin-based material. According to the adhesive sheet described in item 1 of the patent application range, the arithmetic average roughness Ra of the base material is set by applying pressure to the base material roller. According to the adhesive sheet described in item 6 of the patent application range, the roller used in the above-mentioned roller pressing has a surface composed of a metal material. A method for manufacturing a processed product, comprising: an adhesive sheet having a base material and an adhesive layer provided on one side surface of the base material, and the base material is in accordance with JIS B0601 for the one side surface and both side surfaces opposite to the one side surface : The arithmetic mean roughness Ra specified in 2013 (ISO 4287:1997) is 0.01 μm or more and 0.2 μm or less, the thickness of the adhesive layer is 2 μm or more and 12 μm or less, and the ratio of the adhesive sheet to the substrate , The surface closer to the adhesive layer is adhered to one side surface of the adhesive body including the plate-like component to obtain a bonding process of the first laminate with the adhesive sheet and the plate-like component; by applying the first laminate The base material of the body is extended to divide the plate-shaped component on the adhesive sheet to obtain a second laminated body division process in which a plurality of wafers having a divided body of the plate-shaped component are arranged on the adhesive sheet; and The plurality of wafers of the second layered body are separated from the adhesive sheet respectively, and the top picking process obtained by using the wafer as a processed object is characterized in that, until the start of the division process, laser light is irradiated to focus on the plate shape The focal point set inside the module forms a reforming part forming process in which the reforming part is formed inside the plate-shaped component. According to the method for manufacturing a processed product as described in item 8 of the patent application scope, the first laminate provided in the division process has an additional layer between the adhesive layer and the plate-like component, and in the division process Simultaneously divide the additional layer, and in the top picking process, the wafer separated from the adhesive sheet has the divided body of the plate-shaped component and the additional formed on the surface of the divided body of the plate-shaped component adjacent to the adhesive sheet Layer division. According to the method of manufacturing a processed product as described in item 9 of the patent application scope, the additional layer has a protective layer. According to the method for manufacturing a processed product according to item 10 of the patent application scope, until the start of the division process, a protective film forming process including forming the protective layer of the first layered body from a thin film of a protective film. According to the method of manufacturing a processed product as described in item 9 of the patent application scope, the additional layer has a grain bonding layer.