KR20200017348A - Backgrind tape - Google Patents

Abstract

The present invention relates to a back-grinding tape used in a back-grinding process performed after dicing and, more specifically, to a back-grinding tape which prevents chip dropping which may occur during back-grinding. The back-grinding tape of the present invention comprises an adhesive layer, an intermediate layer, and a first substrate in this order, wherein a material constituting the intermediate layer is an acrylic resin having a carboxyl group and not cross-linked, and the initial adhesive strength is 1 to 30 N per 20 mm, when the adhesive layer is adhered to a Si mirror wafer.

Description

Backgrinding Tape {BACKGRIND TAPE}

The present invention relates to a backgrinding tape. More specifically, it is related with the backgrinding tape used suitably in the backgrinding process performed after a dicing process.

A workpiece (for example, a semiconductor wafer), which is an assembly of electronic components, is manufactured with a large diameter, cut off (dicing) into element pieces, and then proceeds to the mounting process again. In this dicing process, a workpiece is cut | disconnected and small-sized. In order to fix the workpiece | work after dicing, after dicing an adhesive tape (dicing tape) normally, a dicing is performed (for example, patent document 1). As one of the dicing methods, the method of dicing a workpiece | work by a laser beam is known. As such a dicing method, the laser beam is condensed on the surface of a workpiece | work, the groove | channel is formed in the surface of the said workpiece | work, and the method of cutting | disconnecting a workpiece | work is used abundantly. On the other hand, in recent years, stealth dicing which condenses a laser beam inside a workpiece | work and modifies a workpiece | work at the said location, and cuts a workpiece | work is also proposed.

In general, in the processing of a semiconductor wafer, grinding the back surface to a predetermined thickness (for example, 100 µm to 600 µm) is performed (backgrinding step). Conventionally, after forming a pattern on the surface of a semiconductor wafer, the surface is fixed to a backgrinding tape and back grinding (backgrinding) is performed, and the dicing process is performed after that. On the other hand, in recent years, in order to improve the usefulness of the said stealth dicing, after performing a stealth dicing, the technique of fixing a surface to a backgrinding tape and performing a backgrinding process is examined.

Japanese Patent Laid-Open No. 2003-007646

As mentioned above, when dicing is performed before the backgrinding process, a new problem arises in that chipped chips interfere with each other at the time of backgrinding, resulting in chip falling.

An object of the present invention is to provide a backgrinding tape, which is a backgrinding tape used in a backgrinding process performed after dicing, and which prevents chip fall that may occur during backgrinding.

The backgrinding tape of this invention is equipped with an adhesive layer, an intermediate | middle layer, and a 1st base material in this order, The material which comprises the said intermediate | middle layer is acrylic resin which has a carboxyl group and is not bridge | crosslinked, The said adhesive layer The initial adhesive force at the time of adhering to a Si mirror wafer is 1N / 20mm-30N / 20mm.

In one embodiment, the said backgrinding tape further has a 2nd base material, and the said 2nd base material is arrange | positioned on the opposite side to the intermediate | middle layer of the said 1st base material.

In one embodiment, the said 1st base material is comprised from polyethylene terephthalate.

In one embodiment, the said 2nd base material is comprised from polyolefin resin.

In one embodiment, the thickness of the said adhesive layer is 1 micrometer-50 micrometers.

In one embodiment, the thickness of the said intermediate | middle layer is 5 micrometers-50 micrometers.

In one embodiment, the said backgrinding tape is used when back-grinding a stealth diced semiconductor wafer.

According to the present invention, it is possible to provide a backgrinding tape which prevents chip falling that may occur during backgrinding. The backgrinding tape of this invention is especially useful as a backgrinding tape used for the backgrinding process performed after dicing (preferably stealth dicing).

1 is a schematic cross-sectional view of a backgrinding tape according to one embodiment of the present invention.
2 is a schematic cross-sectional view of a backgrinding tape according to another embodiment of the present invention.

A. Overview of Backgrind Tape

1 is a schematic cross-sectional view of a backgrinding tape according to one embodiment of the present invention. The backgrinding tape 100 which concerns on this embodiment is equipped with the adhesive layer 10, the intermediate | middle layer 20, and the 1st base material 31. FIG. Although not shown in figure, the peeling liner may be provided in the outer side of an adhesive layer for the purpose of protecting an adhesive surface, until it uses for the backgrinding tape of this invention (not shown). In addition, as long as the effect of this invention is acquired, the backgrinding tape may further contain arbitrary other appropriate layers. Preferably, the intermediate layer is disposed directly on the first substrate. Also preferably, the pressure-sensitive adhesive layer is disposed directly on the intermediate layer.

The backgrinding tape of the present invention can be suitably used to fix the semiconductor wafer when the diced semiconductor wafer is back ground (backgrinded), and is particularly suitable when employing stealth dicing as the dicing. Can be used. Stealth dicing means forming a modified layer in the inside of a semiconductor wafer by irradiation of a laser beam. The semiconductor wafer can be cut from the modified layer as a starting point.

In this invention, the backgrinding tape used for the backgrinding process performed after dicing by using the adhesive layer and the intermediate | middle layer, combining, and using acrylic resin which has a carboxyl group and is not crosslinked as a material which comprises an intermediate | middle layer is used. It is possible to provide a backgrinding tape that prevents chip falling that may occur during backgrinding. The backgrinding tape of the present invention configured as described above has a feature that it is difficult to be deformed to the external force in the surface direction, and it is difficult to return to its original shape after deformation. By using such a backgrinding tape, it is possible to prevent chips that have been fragmented after dicing from excessively interfering with each other and to prevent problems such as falling of the chips and backgrinding. The backgrinding tape of the present invention is particularly useful for semiconductor wafer processing including stealth dicing.

2 is a schematic cross-sectional view of a backgrinding tape according to another embodiment of the present invention. In the backgrinding tape 200 according to this embodiment, the substrate has a two-layer structure, and further includes a second substrate 32. The second base material 32 is disposed on the side opposite to the intermediate layer 20 of the first base material 31. That is, the backgrinding tape 200 is equipped with the adhesive layer 10, the intermediate | middle layer 20, the 1st base material 31, and the 2nd base material 32 in this order. Preferably, as the second substrate, a substrate that is more flexible (eg, lower modulus of elasticity) than the first substrate is used. The backgrinding tape according to the present embodiment can more preferably prevent problems such as chipping off during backgrinding. Semiconductor wafer processing including stealth dicing generates cracks (so-called BHCs) extending from the deteriorated layer formed by the laser beam to the wafer surface to fragment the semiconductor wafer, but embodiments in which the cracks are generated before backgrinding Of course, also in embodiment which becomes more difficult to process, ie, embodiment which generate | occur | produces the said crack at the time of backgrinding, the problem of chip | tip fall etc. can be prevented. In addition, the structure of the base material may be three or more layers.

The initial adhesive force at the time of adhering the adhesive layer of the backgrinding tape of the present invention to the Si mirror wafer is preferably 1 N / 20 mm to 30 N / 20 mm, more preferably 2 N / 20 mm to 20 N / 20 mm. More preferably, they are 3N / 20mm-15N / 20mm, Especially preferably, they are 4N / 20mm-10N / 20mm. If it is such a range, the backgrinding tape which can fix | immobilize a semiconductor wafer favorably at the time of backgrinding can be obtained. In addition, although the backgrinding tape of this invention can be made into the tape whose adhesive force may fall by irradiation of an active energy ray (for example, ultraviolet-ray), the said "initial stage adhesive force" irradiates an active energy ray It means the adhesive force before the following. In the present invention, the adhesive force is measured according to JIS Z 0237: 2000. Specifically, adhesive force is measured on the conditions of 23 degreeC, peeling speed 300mm / min, and peeling angle: 180 degree using the tensile tester (Tensilon, Shimadzu Corporation make).

The thickness of the backgrinding tape is preferably 35 µm to 500 µm, more preferably 60 µm to 300 µm, still more preferably 80 µm to 200 µm.

B. Description

B-1. First description

As said 1st base material, a resin film is used preferably. As resin which comprises a resin film, For example, polyester-based resins, such as polyethylene terephthalate (PET), polyolefin-based resins, such as polypropylene (PP), polyimide (PI), polyetherimide (PEI), polyphenyl Ren sulfide (PPS), polysulfone (PSF), polyether ether ketone (PEEK), polyarylate (PAR) and the like. Among these, Preferably, it is polyester-type resin, Especially preferably, it is polyethylene terephthalate. By using the first base material composed of polyethylene terephthalate, a backgrinding tape can be obtained that can more preferably prevent problems such as chipping off during backgrinding.

The tensile modulus at 23 ° C. of the first substrate is preferably 50 MPa to 10000 MPa, more preferably 100 MPa to 5000 MPa. The measurement of the tensile elasticity modulus of the 1st base material (and each layer (after-mentioned) which comprises a backgrinding tape) measured the distance between chucks using a tensile tester ("AG-IS" by Shimadzu), 50 mm, tensile speed: 300 mm / min, sample width: 10 mm.

The thickness of the first substrate is preferably 25 µm to 200 µm, more preferably 30 µm to 150 µm, still more preferably 40 µm to 100 µm, and particularly preferably 40 µm to 80 µm. .

The first substrate may further include any suitable additive. As an additive, a lubricating agent, antioxidant, a ultraviolet absorber, a processing aid, a filler, an antistatic agent, a stabilizer, an antibacterial agent, a flame retardant, a coloring agent, etc. are mentioned, for example.

B-2. 2nd base

As said 2nd base material, a resin film is used preferably. As resin which comprises a resin film, For example, polyester-based resins, such as polyethylene terephthalate (PET), polyolefin-based resins, such as polypropylene (PP), polyimide (PI), polyetherimide (PEI), polyphenyl Ren sulfide (PPS), polysulfone (PSF), polyether ether ketone (PEEK), polyarylate (PAR) and the like. Especially, polyolefin resin is preferable.

In one embodiment, the said 2nd base material contains polyethylene resin or polypropylene resin. As polyethylene-type resin, a low density polyethylene, linear polyethylene, a medium density polyethylene, a high density polyethylene, an ultra low density polyethylene, etc. are mentioned, for example. In polyethylene-type resin, the content rate of the structural unit derived from ethylene becomes like this. Preferably it is 80 mol% or more, More preferably, it is 90 mol% or more, More preferably, it is 95 mol% or more. As structural units other than the structural unit derived from ethylene, the structural unit derived from the monomer copolymerizable with ethylene and a copolymer is mentioned, For example, propylene, 1-butene, isobutene, 1-pentene, 2-methyl-1- Butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetra Decene, 1-hexadecene, 1-octadecene, 1-icocene and the like.

In one embodiment, the base material comprised from polyethylene terephthalate is used as a 1st base material, and the base material comprised from polyolefin resin (preferably the said polyethylene type resin or polypropylene resin) is used as a 2nd base material. use. Use of these substrates can more preferably prevent problems such as chipping off during backgrinding.

The tensile modulus at 23 ° C of the second substrate is preferably 50 MPa to 2000 MPa, more preferably 100 MPa to 1000 MPa.

It is preferable that the tensile elasticity modulus at 23 degreeC of a said 2nd base material is smaller than the tensile elasticity modulus at 23 degreeC of a said 1st base material. The tensile modulus at 23 ° C of the second base material is preferably 0.5% to 100%, more preferably 0.5% or more and less than 100%, relative to the tensile modulus at 23 ° C of the first base material, More preferably, they are 1%-50%.

The thickness of the second substrate is preferably 25 µm to 200 µm, more preferably 30 µm to 150 µm, still more preferably 40 µm to 100 µm, and particularly preferably 40 µm to 80 µm. .

The second substrate may further include any suitable additive. As an additive, a lubricating agent, antioxidant, a ultraviolet absorber, a processing aid, a filler, an antistatic agent, a stabilizer, an antibacterial agent, a flame retardant, a coloring agent, etc. are mentioned, for example.

The first substrate and the second substrate may be laminated through any suitable adhesive layer. The thickness of the adhesive bond layer between these base materials is 2 micrometers-10 micrometers, for example.

C. Middle Layer

The said intermediate | middle layer is comprised with acrylic resin which has a carboxyl group and is not bridge | crosslinking (for example, epoxy bridge | crosslinking). Such an intermediate layer may be formed of an intermediate layer forming composition containing an acrylic resin having a carboxyl group in the side chain and not containing a crosslinking compound such as a crosslinking agent that reacts with the carboxyl group to form a crosslinked structure. Acrylic resin which comprises an intermediate | middle layer is obtained by superposing | polymerizing the monomer component containing a (meth) acrylic-acid alkylester and a carboxyl group-containing monomer, and the structural unit derived from the (meth) acrylic-acid alkylester and the structural unit derived from a carboxyl group-containing monomer (on a side chain) Structural unit having a carboxyl group). The presence or absence of crosslinking of acrylic resin can be confirmed by thermal decomposition GC / MS analysis.

As said (meth) acrylic-acid alkylester, For example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, ( Isopentyl methacrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl acrylate (meth) acrylic acid Isononyl, decyl acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, penta (meth) acrylate Straight or branched chain having 4 to 20 carbon atoms of alkyl groups such as decyl, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and echoyl (meth) acrylate Alkyl (meth) acrylate having an alkyl group And the like. Among these, from the viewpoint of adhesion to the adherend and bonding workability, alkyl (meth) acrylates having 5 to 12 carbon atoms in the alkyl group are preferable, and more preferably n-butyl acrylate or 2-ethylhexyl acrylate ( 2EHA). (Meth) acrylic-acid alkylester can be used individually by 1 type or in combination of 2 or more type.

In the said acrylic resin, the content rate of the structural unit derived from (meth) acrylic-acid alkylester becomes like this. Preferably it is 70 weight part-98 weight part with respect to 100 weight part of acrylic resin, More preferably, it is 85 weight part-96 weight part It is wealth.

As said carboxyl group-containing monomer, For example, ethylenic unsaturated monocarboxylic acids, such as acrylic acid (AA), methacrylic acid (MAA), crotonic acid; And ethylenically unsaturated dicarboxylic acids such as maleic acid, itaconic acid and citraconic acid. The acrylic resin has a carboxyl group in the side chain, and the backgrinding tape having an intermediate layer composed of such an acrylic resin prevents chip falling that may occur during backgrinding. A carboxyl group-containing monomer can be used individually by 1 type or in combination of 2 or more type.

In the said acrylic resin, the content rate of the structural unit derived from a carboxyl group-containing monomer becomes like this. Preferably it is 2 weight part-30 weight part, More preferably, it is 4 weight part-15 weight part, with respect to 100 weight part of acrylic resin, Especially preferably, they are 4 weight part-8 weight part. Moreover, the content rate of the structural unit derived from a carboxyl group-containing monomer becomes like this. Preferably it is 2 weight part-30 weight part with respect to 100 weight part of structural units derived from (meth) acrylic-acid alkylester, More preferably, it is 5 weight part- It is 20 weight part, More preferably, it is 5 weight part-10 weight part.

The said acrylic resin may contain the structural unit derived from the other monomer copolymerizable with the said (meth) acrylic-acid alkylester as needed. As another monomer, the following monomers are mentioned. These monomers can be used individually by 1 type or in combination of 2 or more type.

Hydroxyl-containing monomers: for example 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate Hydroxyalkyl (meth) acrylates such as these; Unsaturated alcohols such as vinyl alcohol and allyl alcohol; Ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and diethylene glycol monovinyl ether;

Amino group-containing monomers: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate;

Cyano group-containing monomers: for example acrylonitrile, methacrylonitrile;

Keto group-containing monomers: diacetone (meth) acrylamide, diacetone (meth) acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate;

Monomers having a nitrogen atom-containing ring: for example N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinyl pipepe Razin, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- (meth) acryloylmorpholine;

Alkoxysilyl group containing monomer: For example, 3- (meth) acryloxypropyl trimethoxysilane, 3- (meth) acryloxypropyl triethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (Meth) acryloxypropylmethyldiethoxysilane.

In the said acrylic resin, the content rate of the structural unit derived from another monomer becomes like this. Preferably it is 40 weight part or less, More preferably, it is 20 weight part or less, More preferably, 10 weight part with respect to 100 weight part of acrylic resin. Or less.

The weight average molecular weight of the said acrylic resin becomes like this. Preferably it is 200,000-3 million, More preferably, it is 250,000-1,500,000. The weight average molecular weight can be measured by GPC (solvent: THF).

The said intermediate | middle layer forming composition may further contain arbitrary appropriate additives. As said additive, a plasticizer, a tackifier, an antioxidant, a filler, a coloring agent, an antistatic agent, surfactant, etc. are mentioned, for example. The additives may be used alone or in combination of two or more thereof. When using 2 or more types of additives, you may add individually, and may add 2 or more types of additives simultaneously. The compounding quantity of the said additive can be set to arbitrary appropriate amounts.

The thickness of the intermediate layer is preferably 5 µm to 50 µm, more preferably 10 µm to 40 µm, and still more preferably 15 µm to 30 µm. Within such a range, problems such as chip falling off during backgrinding can be more preferably prevented.

It is preferable that the thickness of the said intermediate | middle layer is 2 times-20 times with respect to the thickness of the said adhesive layer, It is more preferable that it is 3 times-10 times, It is further more preferable that it is 3 times-7 times. If an intermediate | middle layer and an adhesive layer are comprised by such a thickness, the backgrinding tape which is hard to deform | transform with respect to the external force of a surface direction, and is hard to return to an original shape after deformation can be obtained.

Storage elastic modulus E 'at 23 degrees C of the said intermediate | middle layer becomes like this. Preferably it is 200 Mpa or less, More preferably, it is 30 Mpa-180 Mpa, More preferably, it is 50 Mpa-160 Mpa. If it is this range, the backgrinding tape which is especially excellent in the tracking property with respect to the uneven surface can be obtained. The storage modulus E 'can be measured by the nanoindentation method. Measurement conditions are as follows.

(Measurement device and measurement conditions)

Device: Hysitron Inc. Manufacture Tribo Indenter

Indenter: Berkovich

Measuring method: single indentation measurement

Measuring temperature: 25 ℃

Indentation depth setting: approx. 300 nm

Indentation rate: about 10 nm / sec

Frequency: 100 Hz

Measuring atmosphere: in air

Sample size: 1 cm x 1 cm

The tensile modulus at 23 ° C. of the intermediate layer is preferably 0.05 MPa to 10 MPa, more preferably 0.1 MPa to 5 MPa, still more preferably 0.2 MPa to 3 MPa. If it is such a range, while using a specific material as a material which comprises an intermediate | middle layer, the problem of chip | tip fall at the time of backgrinding, etc. can be prevented more preferably.

D. Adhesive layer

The pressure-sensitive adhesive layer may be composed of any suitable pressure-sensitive adhesive. As an adhesive, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyvinyl ether-type adhesive etc. are mentioned, for example. The said adhesive may be curable adhesives, such as a thermosetting adhesive and an active-energy-ray-curable adhesive, and a pressure-sensitive adhesive may be sufficient as it. Preferably, a curable pressure sensitive adhesive is used. By using a curable pressure sensitive adhesive, a semiconductor wafer can be satisfactorily fixed during backgrinding, and then a backgrinding tape can be obtained that can be easily peeled off by curing the pressure sensitive adhesive layer when peeling is required.

In one embodiment, an acrylic adhesive is used as said adhesive. Preferably, the acrylic pressure sensitive adhesive is curable.

The acrylic pressure sensitive adhesive includes a base polymer as the base polymer. An acryl-type polymer can have a structural unit derived from (meth) acrylic-acid alkylester. As said (meth) acrylic-acid alkylester, For example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, ( Isopentyl methacrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl acrylate (meth) acrylic acid Isononyl, decyl acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, penta (meth) acrylate Straight or branched chain having 4 to 20 carbon atoms of alkyl groups such as decyl, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, and echoyl (meth) acrylate Alkyl (meth) acrylate having an alkyl group And the like. Among these, from the viewpoint of adhesion to the adherend and bonding workability, alkyl (meth) acrylates having 5 to 12 carbon atoms in the alkyl group are preferable, and more preferably n-butyl acrylate or 2-ethylhexyl acrylate ( 2EHA). (Meth) acrylic-acid alkylester can be used individually by 1 type or in combination of 2 or more type.

The said acryl-type polymer may contain the structural unit derived from the other monomer copolymerizable with the said (meth) acrylic-acid alkylester as needed. As another monomer, the following monomers are mentioned. These monomers can be used individually by 1 type or in combination of 2 or more type.

Carboxyl group-containing monomers and their anhydrides: For example, ethylenically unsaturated monocarboxylic acids such as acrylic acid (AA), methacrylic acid (MAA), crotonic acid; Ethylenic unsaturated dicarboxylic acids such as maleic acid, itaconic acid and citraconic acid and anhydrides thereof (maleic anhydride, itaconic anhydride, etc.);

Hydroxyl-containing monomers: for example 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate Hydroxyalkyl (meth) acrylates such as these; Unsaturated alcohols such as vinyl alcohol and allyl alcohol; Ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and diethylene glycol monovinyl ether;

Amino group-containing monomers: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate;

Epoxy group containing monomers: For example, glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, allyl glycidyl ether;

Cyano group-containing monomers: for example acrylonitrile, methacrylonitrile;

Keto group-containing monomers: diacetone (meth) acrylamide, diacetone (meth) acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetoacetate, vinyl acetoacetate;

Monomers having a nitrogen atom-containing ring: for example N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinyl pipepe Razin, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- (meth) acryloylmorpholine;

Alkoxysilyl group containing monomer: For example, 3- (meth) acryloxypropyl trimethoxysilane, 3- (meth) acryloxypropyl triethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (Meth) acryloxypropylmethyldiethoxysilane;

Isocyanate group containing monomers: (meth) acryloyl isocyanate, 2- (meth) acryloyloxyethyl isocyanate, m-isopropenyl (alpha), (alpha)-dimethylbenzyl isocyanate.

In the said acrylic polymer, the content rate of the structural unit derived from the said other monomer is less than 50 weight part with respect to 100 weight part of acrylic polymer, More preferably, it is 2 weight part-40 weight part, More preferably, 5 Parts by weight to 30 parts by weight.

The weight average molecular weight of the said acrylic polymer becomes like this. Preferably it is 200,000-3 million, More preferably, it is 250,000-1,500,000.

The said adhesive may further contain arbitrary appropriate additives. As said additive, a photoinitiator, a crosslinking agent, a plasticizer, a tackifier, an antioxidant, a filler, a coloring agent, an antistatic agent, surfactant, etc. are mentioned, for example. The additives may be used alone or in combination of two or more thereof. When using 2 or more types of additives, you may add individually, and may add 2 or more types of additives simultaneously. The compounding quantity of the said additive can be set to arbitrary appropriate amounts.

In one embodiment, the said adhesive further contains a photoinitiator. Arbitrary suitable initiator can be used as a photoinitiator. As a photoinitiator, For example, Acyl phosphine oxide type photoinitiators, such as ethyl 2,4,6-trimethylbenzylphenyl phosphinate and (2,4,6- trimethylbenzoyl) -phenylphosphine oxide; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1 Α-ketol compounds such as hydroxycyclohexylphenyl ketone; Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane Acetophenone compounds such as -1; Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; Ketal compounds such as benzyl dimethyl ketal; Aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; Optically active oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; Benzophenone compounds such as benzophenone, benzoylbenzoic acid and 3,3'-dimethyl-4-methoxybenzophenone; Thioxanthone, 2-chloro thioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, 2, 4- dichloro thioxanthone, 2, 4- diethyl thioxide Thioxanthone type compounds, such as a santone and 2, 4- diisopropyl thioxanthone; Camphorquinone; Halogenated ketones; Acyl phosphonate etc. are mentioned. Especially, it is an acyl phosphine oxide type photoinitiator. The amount of the photopolymerization initiator used is preferably 1 part by weight to 20 parts by weight, more preferably 2 parts by weight to 15 parts by weight, and even more preferably 3 parts by weight to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer. It is wealth.

In one embodiment, the said adhesive further contains a crosslinking agent. Arbitrary suitable crosslinking agents can be used as said crosslinking agent. For example, isocyanate crosslinking agent, epoxy crosslinking agent, melamine crosslinking agent, peroxide crosslinking agent, urea crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal salt crosslinking agent, carbodiimide crosslinking agent, oxazoline crosslinking agent, aziri A dine crosslinking agent, an amine crosslinking agent, etc. are mentioned. Only 1 type may be used for a crosslinking agent, and may be used for it in combination of 2 or more type. In addition, the usage-amount of a crosslinking agent can be set to arbitrary appropriate values according to a use use. The amount of the crosslinking agent used is preferably 0.1 part by weight to 10 parts by weight, more preferably 0.5 part by weight to 5 parts by weight, and still more preferably 1 part by weight to 3 parts by weight with respect to 100 parts by weight of the acrylic polymer. .

In one embodiment, an isocyanate crosslinking agent is used preferably. An isocyanate type crosslinking agent is preferable at the point which can react with various functional groups. As a specific example of the said isocyanate type crosslinking agent, Lower aliphatic polyisocyanates, such as butylene diisocyanate and hexamethylene diisocyanate; Alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; Aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; Trimethylolpropane / tolylene diisocyanate trimer adduct (the Nippon Polyurethane high school company make, brand name "coronate L"), trimethylol propane / hexamethylene diisocyanate trimer adduct (The Nippon polyurethane high school make, brand name "Koro Isocyanate adducts, such as isocyanurate body (made by Nippon Polyurethane Co., Ltd., brand name "coronate HX") of hexamethylene diisocyanate; Etc. can be mentioned. Preferably, a crosslinking agent having three or more isocyanate groups is used.

The thickness of the pressure-sensitive adhesive layer is preferably 1 µm to 50 µm, more preferably 1 µm to 25 µm, and still more preferably 1 µm to 5 µm. Within this range, problems such as chip falling off during backgrinding can be more preferably prevented.

Storage elastic modulus E 'at 23 degrees C of the said adhesive layer becomes like this. Preferably it is 15 Mpa-200 Mpa, More preferably, it is 20 Mpa-150 Mpa, More preferably, it is 30 Mpa-120 Mpa. If it is this range, the backgrinding tape which is especially excellent in the tracking property with respect to the uneven surface can be obtained.

The tensile elasticity modulus at 23 degrees C of the said adhesive layer becomes like this. Preferably it is 0.01 Mpa-2 Mpa, More preferably, it is 0.05 Mpa-1 Mpa, More preferably, it is 0.1 Mpa-0.5 Mpa. Within such a range, problems such as chip falling off during backgrinding can be more preferably prevented. Moreover, when an adhesive layer is curable, it is preferable that the adhesive layer tensile elasticity modulus before hardening is the said range.

E. Method of Making Backgrind Tape

The backgrinding tape can be produced by any suitable method. The backgrind tape is, for example, coated (coated and dried) the composition for forming an intermediate layer on a substrate (first substrate) to form an intermediate layer, and then the adhesive is coated (coated and dried) on the intermediate layer. It can be obtained by forming a layer. As the coating method, various methods such as bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexo printing, and screen printing can be adopted. In addition, after forming an adhesive layer and an intermediate | middle layer separately on a peeling liner, you may employ | adopt the method etc. which transfer and bond it.

EXAMPLE

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The test and evaluation method in an Example are as follows. In addition, "part" and "%" are basis of weight unless there is particular notice.

(1) adhesion

The backgrinding tape was cut into the rectangle of width 20mm, and the sample was produced.

The sample was subjected to a 180 ° peel test under the following conditions in accordance with JIS Z 0237 to measure the adhesive force of the backgrinding tape.

<180 ° peel test>

Substrate: Si Mirror Wafer

Number of replicate exams: 3

Temperature: 23 ℃

Peeling Angle: 180 Degree

Peeling Speed: 300 mm / min

Initial length (chuck spacing): 150 mm

(2) Crack (chip fall) evaluation

On one side of a 12-inch Si mirror wafer (thickness: 775 μm), a backgrinding tape was adhered under the following conditions, and then stealth dicing was performed under the following conditions from the side opposite to the adhesive side of the backgrinding tape, 680 small pieces of 8 mm x 12 mm were expected to be obtained, and a modified layer was formed inside the mirror wafer.

Next, backgrinding was performed so that the thickness of a mirror wafer might be set to 25 micrometers on condition of the following.

Next, the mirror wafer after backgrinding was mounted in dicing tape (Nitto Denko Corporation make, brand name "NLS-516P") and a ring frame by inline conveyance.

Thereafter, the surface of the mirror wafer was observed with an optical microscope (× 200) over a dicing tape to confirm the occurrence of cracks, and the ratio of the number of cracks (number of cracked pieces) to the total number of pieces (680). The crack evaluation was performed by this.

<Stealth dicing condition>

Equipment: Disco company, DFL7361 SDE06

Treatment Condition: BHC, Non BHC

<Backgrinding tape sticking condition>

Device: Nitto Seiki DR-3000III

Pressure: 0.3MPa

Temperature: room temperature

Speed: 10mm / min

<Backgrinding condition>

Equipment: Disco company, DGP8761 DFM2800 inline grinder

After thin film with Z1 (# 360) and Z2 (# 2000), GDP (gettering DP processing) is performed.

(3) storage modulus

The storage elastic modulus E 'of an intermediate | middle layer and an adhesive layer was measured by the nanoindentation method on condition of the following.

<Measurement of storage modulus E '>

Device: Hysitron Inc. Manufacture Tribo Indenter

Indenter: Berkovich

Measuring method: single indentation measurement

Measuring temperature: 23 ℃

Indentation depth setting: approx. 300 nm

Indentation rate: about 10 nm / sec

Frequency: 100 Hz

Measuring atmosphere: in air

Sample size: 1 cm x 1 cm

Preparation Example 1 Preparation of Composition M1 for Intermediate Layer Formation

A mixture obtained by mixing 30 parts by weight of 2ethylhexyl acrylate, 70 parts by weight of methyl acrylate, 10 parts by weight of acrylic acid, 0.1 part by weight of azobisisobutyronitrile, and 100 parts by weight of ethyl acetate was prepared under a nitrogen atmosphere. It superposed | polymerized at 60 degreeC for 6 hours, and obtained the weight average molecular weight and 500,000 acrylic resin M1.

The polymerization liquid obtained by the said operation was made into composition M1 for intermediate | middle layer formation.

Preparation Example 2 Preparation of Composition M2 for Interlayer Formation

A mixture obtained by mixing 50 parts by weight of butyl acrylate, 50 parts by weight of ethyl acrylate, 5 parts by weight of acrylic acid, 0.1 part by weight of azobisisobutyronitrile, and 100 parts by weight of ethyl acetate, was subjected to a nitrogen atmosphere at 60 ° C. It superposed | polymerized in 6 hours and obtained acrylic resin M2 of the weight average molecular weight 650,000.

The polymerization liquid obtained by the said operation was made into composition M2 for intermediate | middle layer formation.

Preparation Example 3 Preparation of Composition M3 for Interlayer Formation

1 weight part of adduct body (Nipbon polyurethane high school company make, brand name "coronate L") of trimethylol propane / tolylene diisocyanate, and polyether polyol (ADEKA company make, brand name "adeka polyether EDP-300") 0.05 parts by weight were mixed, and a composition containing the reactants produced by the reaction of these compounds was obtained.

1.05 weight part of obtained composition was added to the composition M1 for intermediate | middle layer formation (100 weight part of acrylic resin M1 content) prepared in the manufacture example 1, and the composition M3 for intermediate | middle layer formation was prepared.

In addition, the reactant does not crosslink the acrylic resin.

Production Example 4 Preparation of Composition M1 ′ for Intermediate Layer Formation

1 weight part of epoxy type crosslinking agents (Mitsubishi Gas Corporation make, brand name "Tetrad C") was added to the said composition M1 for intermediate | middle layer forming, and the composition M1 'for intermediate | middle layer forming was obtained.

Production Example 5 Preparation of Adhesive A1

100 parts by weight of 2ethylhexyl acrylate, 26 parts by weight of acryloyl morpholine, 18 parts by weight of hydroxyethyl acrylate, 12 parts by weight of 2-methacryloyloxyethyl isocyanate, and azobisisobutyronitrile The mixture obtained by mixing 0.2 weight part and 500 weight part of ethyl acetate was polymerized at 60 degreeC for 24 hours in nitrogen atmosphere, and the acrylic polymer A of the weight average molecular weight 900,000 was obtained.

To the polymerization liquid (acrylic-polymer A content: 100 weight part) obtained by the said operation, 7 weight part of photoinitiators (IGM Resines company make, brand name "OmniradTPO"), and an isocyanate type crosslinking agent (Nippon Polyurethane Co., Ltd. make, brand name) 2 parts by weight of "coronate C") was added to obtain an adhesive A1.

Preparation Example 6 Preparation of Adhesive A2

Except having made the compounding quantity of a photoinitiator into 3 weight part, it carried out similarly to manufacture example 5, and obtained adhesive A2.

Production Example 7 Preparation of Adhesive A2 '

The pressure-sensitive adhesive A2 'was obtained in the same manner as in Production Example 5 except that the blending amount of the photoinitiator was 3 parts by weight and a crosslinking aid (manufactured by ADEKA Corporation, trade name "adeka polyether EDP-300") was further added.

Preparation Example 8 Preparation of Adhesive B1

100 parts by weight of butyl acrylate, 78 parts by weight of ethyl acrylate, 40 parts by weight of hydroxyethyl acrylate, 44 parts by weight of 2-methacryloyloxyethyl isocyanate, 0.2 parts by weight of azobisisobutyronitrile, The mixture obtained by mixing 500 weight part of ethyl acetate was polymerized at 60 degreeC for 24 hours in nitrogen atmosphere, and the acrylic polymer B of the weight average molecular weight 500,000 was obtained.

3 weight part of photoinitiators (IGM Resines, make, brand name "OmniradTPO"), and an isocyanate type crosslinking agent (made by Nippon Polyurethane Co., Ltd.), to a polymerization liquid (acrylic-polymer B content: 100 weight part) obtained by the said operation. 2.5 weight part of "coronate C") was added, and adhesive B1 was obtained.

Preparation Example 9 Preparation of Adhesive B2

Except having made the compounding quantity of a crosslinking agent into 0.2 weight part, it carried out similarly to manufacture example 8, and obtained adhesive B2.

Example 1

Polyethylene terephthalate base material (Toray Corporation make, brand name "S105 # 50", thickness: 50 micrometers) as a 1st base material, and a polyethylene base material (Futamura Kagaku Corporation make, brand name "LL-XMTN # 50", thickness as a 2nd base material) : 50 µm) was laminated through an adhesive (thickness: 2 µm).

Next, the composition M1 for intermediate | middle layer forming was coated on the 1st base material, and the intermediate | middle layer of thickness 28micrometer was formed. Then, the adhesive A1 was coated on the intermediate | middle layer, and the adhesive layer of thickness 5micrometer was formed.

As described above, a backgrinding tape A was obtained. Obtained backgrinding tape A was provided for the said evaluation. The results are shown in Table 1.

Example 2

The backgrinding tape B was obtained like Example 1 except having formed the intermediate | middle layer (thickness: 28 micrometers) using the intermediate | middle layer forming composition M2 instead of the intermediate | middle layer forming composition M1. Obtained backgrinding tape B was provided for the said evaluation. The results are shown in Table 1.

Example 3

The backgrinding tape C was obtained like Example 1 except having set the thickness of the intermediate | middle layer to 18 micrometers, and using the adhesive A2 instead of adhesive A1 and forming the adhesive layer (thickness: 5 micrometers). Obtained backgrinding tape C was provided for the said evaluation. The results are shown in Table 1.

Example 4

Instead of the intermediate layer formation composition M1, the intermediate layer formation composition M3 was used, the thickness of the intermediate layer was 18 micrometers, and the adhesive layer (thickness: 5 micrometers) was formed using adhesive A2 'instead of adhesive A1. A backgrinding tape D was obtained in the same manner as in Example 1 except for the above. The obtained backgrinding tape D was provided for the above evaluation. The results are shown in Table 1.

Example 5

The composition M1 for intermediate | middle layer forming was coated on the polyethylene terephthalate base material (Toray Corporation make, brand name "S105 # 50", thickness: 50 micrometers) as a 1st base material, and the intermediate | middle layer of thickness 25micrometer was formed. Then, the adhesive A1 was coated on the intermediate | middle layer, and the adhesive layer of thickness 5micrometer was formed.

As described above, the backgrinding tape E was obtained. The obtained backgrinding tape E was provided for the said evaluation. The results are shown in Table 1.

Example 6

Backgrinding tape F was obtained like Example 5 except having used adhesive A2 instead of adhesive A1. The obtained backgrinding tape F was provided for the said evaluation. The results are shown in Table 1.

Comparative Example 1

Adhesive A2 was coated on the polyethylene terephthalate base material (Toray Corporation make, brand name "S105 # 50", thickness: 50 micrometers) as a 1st base material, and the adhesive layer of thickness 30micrometer was formed.

As described above, the backgrinding tape G was obtained. Obtained backgrinding tape G was provided for the said evaluation. The results are shown in Table 1.

Comparative Example 2

The backgrinding tape H was obtained like Comparative Example 1 except having used the adhesive B1 instead of the adhesive A2. Backgrinding tape H was provided for this evaluation. The results are shown in Table 1.

Comparative Example 3

A backgrinding tape J was obtained in the same manner as in Comparative Example 1 except that the adhesive B2 was used instead of the adhesive A2. Backgrinding tape J was provided for this evaluation. The results are shown in Table 1.

[Comparative Example 4]

The composition M1 'for intermediate | middle layer forming was coated on the polyethylene terephthalate base material (Toray Corporation make, brand name "S105 # 50", thickness: 50 micrometers) as a 1st base material, and the intermediate | middle layer of thickness 28micrometer was formed. Thereafter, pressure-sensitive adhesive A2 was coated on the intermediate layer to form a pressure-sensitive adhesive layer having a thickness of 5 μm.

As described above, the backgrinding tape K was obtained. The obtained backgrinding tape K was provided for the above evaluation. The results are shown in Table 1.

[Comparative Example 5]

Coating composition M4 for intermediate | middle layer forming containing an acrylic urethane resin on the polyethylene terephthalate base material (Toray Corporation make, brand name "Lumier ES10 # 75", thickness: 75 micrometers) as a 1st base material, Formed. Then, adhesive B2 was coated on the intermediate | middle layer, and the adhesive layer of thickness 50micrometer was formed. In addition, preparation of the composition M4 for intermediate | middle layer forming was performed as follows.

As described above, a backgrinding tape L was obtained. The obtained backgrinding tape L was provided for the said evaluation. The results are shown in Table 1.

<Preparation of composition M4 for intermediate layer formation>

70 parts by weight of polytetramethylene ether glycol, 50 parts by weight of tert-butyl acrylate, 30 parts by weight of acrylic acid, 20 parts by weight of butyl acrylate, and an isocyanate compound (Mitsui Chemical Co., Ltd., trade name "Takenate 500") The mixture obtained by mixing 25 weight part, 0.1 weight part of azobisisobutyronitrile, and 100 weight part of ethyl acetate was superposed | polymerized at 60 degreeC under nitrogen atmosphere for 6 hours, and obtained the polymerization liquid containing an acrylic urethane resin.

5 weight part of crosslinking agents (trimethylol propane triacrylate) were added with respect to 100 weight part of acrylic urethane resins, and the composition M4 for intermediate | middle layer formation was obtained to the said polymerization liquid.

10: adhesive layer
20: middle layer
31: first description
32: second description
100: backgrinding tape

Claims (8)

An adhesive layer, an intermediate | middle layer, and a 1st base material are provided in this order,
The material which comprises the said intermediate | middle layer is acrylic resin which has a carboxyl group and is not crosslinked,
The backgrinding tape whose initial adhesive force at the time of sticking the said adhesive layer to a Si mirror wafer is 1N / 20mm-30N / 20mm. The method of claim 1,
Further provided with a 2nd base material,
The said back base tape is arrange | positioned on the opposite side to the intermediate | middle layer of the said 1st base material. The method according to claim 1 or 2,
A backgrinding tape, wherein the first base material is made of polyethylene terephthalate. The method of claim 2,
The backgrinding tape of which the said 2nd base material is comprised from polyolefin resin. The method according to claim 1 or 2,
The backgrinding tape whose thickness of the said adhesive layer is 1 micrometer-50 micrometers. The method according to claim 1 or 2,
The backgrinding tape whose thickness of the said intermediate | middle layer is 5 micrometers-50 micrometers. The method according to claim 1 or 2,
The acrylic resin has a structural unit derived from a carboxyl group-containing monomer,
The backgrinding tape whose content rate of the structural unit derived from the said carboxyl group-containing monomer is 2 weight part-30 weight part with respect to 100 weight part of said acrylic resins. The method according to claim 1 or 2,
A backgrinding tape used for backside grinding stealth diced semiconductor wafers.

Images