JP2010017826A - Thin blade grinding wheel and dicing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin blade grinding wheel superior in grinding, cutting property, durability, and balance between rigidity and toughness. <P>SOLUTION: The thin blade grinding wheel consists of polyimide film containing abrasive grains composed of diamond and/or cubic crystal boron nitride (CBN) with an average particle size of 0.1 μm to 10 μm within a range from 5 mass% to 50 mass%, and has a thickness of 1 μm to 30 μm. In the polyimide film, at least a residue of aromatic tetracarboxylic acids is a pyromellitic acid, and a residue of aromatic diamines is a diamine having a benzoxazole structure. The thin blade grinding wheel has a linear expansion coefficient in a planar direction of -10 ppm/°C to 20 ppm/°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thin blade whetstone having a small thickness dimension, and more particularly to a novel thin blade whetstone that can improve the accuracy and efficiency of cutting processing and a method for using the same, and further, the sharpness and durability of the abrasiveness are good, and the sharpness is high even at high temperatures. The present invention relates to a thin blade grindstone that retains the durability of abrasiveness.

In order to cut hard brittle materials such as silicon wafers, quartz and quartz, and metal materials, a thin blade grindstone having a thickness dimension of 1 mm or less is used. For example, in a semiconductor wafer, it is a cutting tool used in a dicing process for dividing semiconductor elements arranged in a matrix form into pellets on a vertical plane regardless of crystal orientation. As a thin blade grindstone, a thin blade grindstone obtained by bonding abrasive grains using a resin binder that is cured by heating or a metal binder that is precipitated in a plating solution has been proposed (see Patent Document 1). ing.
The thin blade whetstone is not only inefficient because it takes time to harden the resin binder or to generate a metal binder, but even though a flat shape with a thickness of several tens to several hundred μm is required, It was difficult to form with high dimensional accuracy.

In order to solve these problems, the fluid grindstone material injected into the mold is irradiated with light through a mold having light permeability, and the photocurable resin of the fluid grindstone material is cured in a short time, and the thickness, diameter A method for obtaining a high-precision thin-blade grindstone such as a warp (see Patent Document 2), a thin-blade grindstone having a thin-plate-shaped abrasive grain holding portion in which an inorganic filler containing abrasive grains is held by a resin binder, A thin-blade grindstone (see Patent Document 3) whose material contains a cured portion of a mixture of an acrylic resin and an epoxy resin has been proposed.
Japanese Patent Laid-Open No. 02-053568 JP 2001-088037 A JP 2003-048167 A

  Conventionally proposed thin blade whetstones have contributed to the field of thin blade whetstones by improving the performance and facilitating production of the thin blade whetstones that precede them, but the balance between rigidity and toughness. There were problems such as lack of durability, lack of durability, and insufficient productivity. The present invention solves these problems, and a thin-blade grindstone having excellent durability, particularly durability at high temperatures, excellent balance between rigidity and toughness, and low loss in productivity, as well as performance as a grindstone. It can be obtained.

That is, this invention consists of the following structures.
1. A polyimide film containing diamond and / or cubic boron nitride (CBN) abrasive grains having an average particle size of 0.1 μm to 10 μm in a range of 5% by mass to 50% by mass, and having a thickness of 1 μm to 30 μm, A thin blade whetstone characterized by being in the shape of an annular plate.
2. The polyimide film is a polyimide film that is at least pyromellitic acid as a residue of aromatic tetracarboxylic acids and a diamine having a benzoxazole structure as a residue of aromatic diamines, and has a linear expansion coefficient of −10 ppm in the plane direction / ° C to 20 ppm / ° C. Thin blade whetstone.
3.1. ~ 2. A dicing method using any of the thin blade grindstones.

  A polyimide film containing diamond and / or cubic boron nitride (CBN) abrasive grains having an average particle diameter of 0.1 μm to 10 μm according to the present invention in a range of 5% by mass to 50% by mass and having a thickness of 1 to 1 A thin blade whetstone of 30 μm, particularly a polyimide film, is a polyimide film that is a diamine having a benzoxazole structure as a residue of pyromellitic acid and an aromatic diamine as a residue of at least an aromatic tetracarboxylic acid, and in a plane direction A thin-blade grindstone with a coefficient of linear expansion of −10 ppm / ° C. to 20 ppm / ° C. is excellent in polishing and cutting properties, excellent in durability, particularly in high temperature, and excellent in balance between rigidity and toughness, and in productivity It is a thin blade whetstone with little loss, and is extremely significant in the manufacture of semiconductor devices that perform dicing using this thin blade whetstone It is.

The present invention is described in detail below.
The polyimide film used in the present invention is a film obtained by reacting an aromatic tetracarboxylic acid and an aromatic diamine, and this polyimide film is made of, for example, an aromatic tetracarboxylic acid (anhydride, acid). And a polyamic acid solution obtained by reacting an amide bond derivative generically referred to as a class, hereinafter) and an aromatic diamine (collectively referred to as a class of amine and amide bond derivative, hereinafter the same). For example, in the case of forming a film, the film is obtained by casting, drying, and heat treatment (imidization) to form a film.

Although the said polyimide film is not specifically limited, The combination of the following aromatic diamine and aromatic tetracarboxylic acid (anhydride) is mentioned as a preferable example.
A. Combination with aromatic tetracarboxylic acid having pyromellitic acid residue and aromatic diamine having benzoxazole structure.
B. A combination of an aromatic diamine having a phenylenediamine skeleton and an aromatic tetracarboxylic acid having a biphenyltetracarboxylic acid skeleton.
C. A combination of an aromatic diamine having a diphenyl ether skeleton and an aromatic tetracarboxylic acid having a pyromellitic acid residue.
In particular, A. A polyimide film having an aromatic diamine residue having a benzoxazole structure is preferred.

The molecular structure of the aromatic diamines having the benzoxazole structure is not particularly limited, and specific examples include the following. These diamines are preferably 70 mol% or more, more preferably 80 mol% or more of the total diamine.

  Among these, from the viewpoint of easy synthesis, each isomer of amino (aminophenyl) benzoxazole is preferable, and 5-amino-2- (p-aminophenyl) benzoxazole is more preferable. Here, “each isomer” refers to each isomer in which two amino groups of amino (aminophenyl) benzoxazole are determined according to the coordination position (eg, the above “formula 1” to “formula 4”). Each compound described in the above. These diamines may be used alone or in combination of two or more.

  Furthermore, as long as it is 30 mol% or less of the total diamine, one or more of the diamines exemplified below may be used in combination. Examples of such diamines include 4,4′-bis (3-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, and bis [4- (3-aminophenoxy) phenyl]. Sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 3,3′-diamino Diphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-dia Nodiphenyl sulfide, 3,3′-diaminodiphenyl sulfoxide, 3,4′-diaminodiphenyl sulfoxide, 4,4′-diaminodiphenyl sulfoxide, 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4 , 4′-diaminodiphenylsulfone, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4, 4′-diaminodiphenylmethane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-amino) Phenoxy) phenyl] ethane, 1,1-bis [4- 4-aminophenoxy) phenyl] propane, 1,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,3-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 1,1-bis [4- (4-aminophenoxy) phenyl] butane, 1,3-bis [4- (4-aminophenoxy) phenyl] butane, , 4-bis [4- (4-aminophenoxy) phenyl] butane, 2,2-bis [4- (4-aminophenoxy) phenyl] butane, 2,3-bis [4- (4-aminophenoxy) phenyl ] Butane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (4-a Minophenoxy) -3-methylphenyl] propane, 2- [4- (4-aminophenoxy) phenyl] -2- [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2- Bis [4- (4-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexa Fluoropropane, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (4 -Aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-amino) Enoxy) phenyl] sulfoxide, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1, 3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] Benzene, 4,4′-bis [(3-aminophenoxy) benzoyl] benzene, 1,1-bis [4- (3-aminophenoxy) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) ) Phenyl] propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenoxy) phenyl -1,1,1,3,3,3-hexafluoropropane, bis [4- (3-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1 , 2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-Amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} fe Sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) phenoxy-α, α-dimethyl Benzyl] benzene, 1,3-bis [4- (4-amino-6-trifluoromethylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-fluoro) Phenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-amino-6-methylphenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4 -Amino-6-cyanophenoxy) -α, α-dimethylbenzyl] benzene, 3,3′-diamino-4,4′-diphenoxybenzophenone, 4,4′-diamino-5,5′-dipheno Cibenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino- 4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 4,4'-diamino-5,5'-dibiphenoxybenzophenone, 3,4′-diamino-4,5′-dibiphenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 4,4′-diamino-5-biphenoxybenzophenone, 3,4′-diamino-4 -Biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone 1,3-bis (3-amino-4-phenoxybenzoyl) benzene, 1,4-bis (3-amino-4-phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-phenoxybenzoyl) Benzene, 1,4-bis (4-amino-5-phenoxybenzoyl) benzene, 1,3-bis (3-amino-4-biphenoxybenzoyl) benzene, 1,4-bis (3-amino-4-bi) Phenoxybenzoyl) benzene, 1,3-bis (4-amino-5-biphenoxybenzoyl) benzene, 1,4-bis (4-amino-5-biphenoxybenzoyl) benzene, 2,6-bis [4- ( 4-amino-α, α-dimethylbenzyl) phenoxy] benzonitrile and some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine are halogen atoms, An alkyl group having 1 to 3 carbon atoms, an alkoxyl group, a cyano group, or an alkyl group or an alkoxyl group having 1 to 3 carbon atoms in which some or all of the hydrogen atoms of the alkyl group or alkoxyl group are substituted with halogen atoms. Examples thereof include substituted aromatic diamines.

  The molecular structure of the aromatic tetracarboxylic acid anhydrides is not particularly limited, and specific examples include the following. These acid anhydrides are preferably 70 mol% or more, more preferably 80 mol% or more of the total acid anhydride.

These tetracarboxylic dianhydrides may be used alone or in combination of two or more.
Furthermore, as long as it is 30 mol% or less of the total tetracarboxylic dianhydrides, one or more of the non-aromatic tetracarboxylic dianhydrides exemplified below may be used in combination. Examples of such tetracarboxylic acid anhydrides include butane-1,2,3,4-tetracarboxylic dianhydride, pentane-1,2,4,5-tetracarboxylic dianhydride, and cyclobutanetetracarboxylic acid. Acid dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, cyclohexane-1,2,4,5-tetracarboxylic dianhydride, cyclohex-1-ene-2,3 5,6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3 -(1,2), 5,6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-ene-3- (1,2), 5,6-tetracarboxylic dianhydride 1-ethylcyclohexane -(1,2), 3,4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane- 1- (2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ′, 4′-tetracarboxylic dianhydride, bicyclo [2.2.1] Heptane-2,3,5,6-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2,3), 3,4-tetracarboxylic dianhydride, 1,3-dipropylcyclohexane-1 -(2,3), 3- (2,3) -tetracarboxylic dianhydride, dicyclohexyl-3,4,3 ', 4'-tetracarboxylic dianhydride, bicyclo [2.2.1] heptane -2,3,5,6-tetracarboxylic dianhydride, bisic [2.2.2] Octane-2,3,5,6-tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride An anhydride etc. are mentioned.

  The solvent used when reacting (polymerizing) the aromatic tetracarboxylic acid and the aromatic diamine to obtain a polyamic acid is particularly suitable as long as it can dissolve both the raw material monomer and the produced polyamic acid. Although not limited, polar organic solvents are preferred, such as N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, dimethyl Examples thereof include sulfoxide, hexamethylphosphoric amide, ethyl cellosolve acetate, diethylene glycol dimethyl ether, sulfolane, and halogenated phenols. These solvents can be used alone or in combination. The amount of the solvent used may be an amount sufficient to dissolve the monomer as a raw material. As a specific amount used, the weight of the monomer in the solution in which the monomer is dissolved is usually 5 to 40% by weight, The amount is preferably 10 to 30% by weight.

  Conventionally known conditions may be applied for the polymerization reaction for obtaining the polyamic acid (hereinafter also simply referred to as “polymerization reaction”). As a specific example, in a temperature range of 0 to 80 ° C., 10 Stirring and / or mixing continuously for minutes to 30 hours. If necessary, the polymerization reaction may be divided or the temperature may be increased or decreased. In this case, the order of adding both monomers is not particularly limited, but it is preferable to add aromatic tetracarboxylic acid anhydrides to the solution of aromatic diamines. The viscosity of the polyamic acid solution obtained by the polymerization reaction is measured with a Brookfield viscometer (25 ° C.), and is preferably 10 to 2000 Pa · s, more preferably 100 to 1000 Pa · s, from the viewpoint of the stability of liquid feeding. It is.

Vacuum degassing during the polymerization reaction is effective in producing a good quality polyamic acid solution. Moreover, you may perform superposition | polymerization by adding a small amount of terminal blockers to aromatic diamines before a polymerization reaction. Examples of the end capping agent include compounds having a carbon-carbon double bond such as maleic anhydride. The amount of maleic anhydride used is preferably 0.001 to 1.0 mole per mole of aromatic diamine.
In order to form a polyimide film, which is one of the layers of the present invention, from a polyamic acid solution obtained by a polymerization reaction, the polyamic acid solution is applied onto a support and dried to form a green film (self-supporting precursor). There is a method in which a body film is obtained, and then an imidization reaction is performed by subjecting the green film to heat treatment, such as application of a polyamic acid solution to a support, casting from a slit-attached die, extrusion by an extruder, etc. However, it is not restricted to these, The conventionally well-known application | coating means of a solution can be used suitably.

  The conditions for drying the polyamic acid coated on the support to obtain a green sheet are not particularly limited, and examples include a temperature of 70 to 150 ° C. and a drying time of 5 to 180 minutes. A conventionally known drying apparatus that satisfies such conditions can be applied, and examples thereof include hot air, hot nitrogen, far infrared rays, and high frequency induction heating. Next, in order to obtain a target polyimide film from the obtained green sheet, an imidization reaction is performed. As a specific method thereof, a conventionally known imidation reaction can be appropriately used. For example, there may be mentioned a method (so-called thermal ring closure method) in which an imidization reaction proceeds by subjecting it to a heat treatment after performing a stretching treatment as necessary using a polyamic acid solution containing no ring closure catalyst or a dehydrating agent. The heating temperature in this case is exemplified by 100 to 500 ° C. From the viewpoint of film physical properties, more preferably, a two-stage heat treatment in which the treatment is performed at 150 to 250 ° C. for 3 to 20 minutes and then treatment at 350 to 500 ° C. for 3 to 20 minutes. Is mentioned.

Another example of the imidization reaction is a chemical ring closure method in which a polyamic acid solution contains a ring closure catalyst and a dehydrating agent, and the imidization reaction is performed by the action of the ring closing catalyst and the dehydrating agent. In this method, after the polyamic acid solution is applied to the support, the imidization reaction is partially advanced to form a film having self-supporting property, and then imidization can be performed completely by heating. In this case, the condition for partially proceeding with the imidization reaction is preferably a heat treatment for 3 to 20 minutes at 100 to 200 ° C., and the condition for allowing the imidization reaction to be completely performed is preferably 200 to 400 ° C. For 3 to 20 minutes.

As the abrasive grains used in the present invention, diamond and CBN are preferable. In addition, Al ₂ O ₃ , SiO ₂ , ZrO ₂ , SiC, B ₄ C, Fe ₂ O ₃ , Cr ₂ O ₃ , CeO ₂ , ZrB ₂ , Abrasive grains such as TiB ₂ and TiC may be added.
The average particle diameter of the abrasive grains used in the present invention is 0.1 μm to 10 μm, preferably 0.1 μm to 5 μm, more preferably 0.1 μm to 3 μm. When the average particle diameter exceeds 10 μm, the mechanical strength of the thin blade grindstone is greatly lowered, and it is difficult to form a film. Moreover, since the thin blade whetstone itself becomes thick, the loss by a kerf becomes large, and there exists a possibility that productivity may worsen. On the other hand, if the average particle diameter is smaller than 0.1 μm, the cutting ability of the thin blade grindstone may be deteriorated. Here, the average particle diameter in the present invention refers to a weight average particle diameter calculated from a particle diameter distribution obtained using a laser scattering particle size distribution analyzer (LB-500, manufactured by Horiba, Ltd.).
Moreover, the thickness of the thin blade grindstone of the present invention is 1 μm to 30 μm, preferably 2 μm to 15 μm, more preferably 3 μm to 12.5 μm. When the thickness exceeds 30 μm, the loss due to the kerf increases and the productivity may be deteriorated. On the other hand, it is very difficult to form a thin blade whetstone thinner than 1 μm, and if it is thinner than 1 μm, the cutting performance deteriorates.

The content ratio of the abrasive grains in the thin blade grindstone of the present invention is preferably 5% by mass to 50% by mass, more preferably 5% by mass to 40% by mass, and further preferably 10% by mass to 40% by mass. When the content of the abrasive grains exceeds 50% by weight, the mechanical strength of the film is greatly reduced, and it is difficult to form a film. On the other hand, if it is less than 5% by weight, the cutting ability of the thin-blade grindstone may be deteriorated.
Examples of means for containing abrasive grains in the polyimide film include means for blending abrasive grains in a solution of polyamic acid that is a precursor of the polyimide film. Specifically, before synthesizing the polyamic acid, after adding and dispersing abrasive grains in an organic polar solvent, the acid anhydrides and diamines are reacted as described above, or abrasive grains are added during the reaction. Or a means of adding abrasive grains after obtaining a polyamic acid solution. Preferably, among the above-mentioned means, means for adding and dispersing abrasive grains in an organic polar solvent before synthesizing the polyamic acid, or means for adding abrasive grains in the middle of the reaction between the polyamic acid and the diamine are mentioned. It is done. With such a means, it is difficult to agglomerate the abrasive grains, and they can be efficiently and uniformly dispersed.

  The method of processing from the polyimide film of the present invention to an annular plate-shaped thin blade grindstone is not particularly limited, but it is possible to use a method such as punching with a Thomson blade, cutting with a circular cutter, or cutting with a laser. it can.

  The thin blade grindstone of the present invention preferably has a linear expansion coefficient in the plane direction of −10 ppm / ° C. to 20 ppm / ° C., more preferably −10 ppm / ° C. to 15 ppm / ° C., further preferably −10 ppm / ° C. to 10 ppm. / ° C. Exceeding these ranges and the value of the linear expansion coefficient deviating significantly from 0, for example, a dimensional change due to a temperature rise during silicon wafer dicing occurs, and the thin blade grindstone is deformed, resulting in an excellent quality silicon chip. There is a fear that it is not possible.

The tensile strength at break of the thin blade grindstone of the present invention is not particularly limited, but is preferably 150 MPa or more, more preferably 200 MPa or more, and further preferably 250 MPa or more. If the tensile strength at break is lower than 150 MPa, for example, the cutting performance is deteriorated during silicon wafer dicing, and there is a possibility that an excellent quality silicon chip cannot be obtained.
The tensile elongation at break is not particularly limited, but is preferably from 5% to 80%, more preferably from 10% to 75%, still more preferably from 15% to 70%, from the purpose of use. When the tensile elongation at break exceeds these ranges, the life is shortened because of poor durability.
Further, the tensile elastic modulus is not particularly limited, but is preferably 3.0 GPa or more, more preferably 4.0 GPa or more, and further preferably 4.5 GPa or more. When the tensile elastic modulus is lower than 3.0 GPa, for example, the cutting performance is deteriorated during silicon wafer dicing, and there is a possibility that an excellent quality silicon chip cannot be obtained.

  A semiconductor wafer can be diced using the thin blade grindstone of the present invention. For example, the thin blade grindstone of the present application can be used as a cutting tool in a dicing process for dividing semiconductor elements arranged in a matrix on a semiconductor wafer into pellets on a vertical plane regardless of the crystal orientation.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited by a following example. In addition, the evaluation method of the physical property in the following examples is as follows.

1. Average particle diameter of abrasive grains The abrasive grains to be measured were dispersed in a solvent, and the particle diameter distribution was determined with a laser scattering particle size distribution analyzer (LB-500, manufactured by Horiba Ltd.) to calculate the weight average particle diameter.
2. Thickness of the thin-blade grindstone The thin-blade grindstone to be measured was measured using a micrometer (manufactured by Fine Reef, Millitron 1245D).
3. Tensile modulus, tensile rupture strength, and tensile rupture elongation of thin blade grindstone The thin blade grindstone to be measured is subjected to a tensile fracture test in the width direction (TD direction) and longitudinal direction (MD direction) under the following conditions. The average value in the direction was defined as tensile modulus, tensile strength at break, and tensile elongation at break.
Device name: Autograph made by Shimadzu Corporation
Sample length: 100mm
Sample width: 10mm
Pulling speed: 50mm / min
Distance between chucks: 40 mm

4). Coefficient of linear expansion (CTE) of thin blade grinding wheel
About the polyimide film to be measured, the stretch rate in the TD direction and the MD direction is measured under the following conditions, and the stretch rate / temperature at intervals of 90 to 100 ° C., 100 to 110 ° C.,. Measurement was performed up to 400 ° C., and an average value of all measured values from 100 ° C. to 350 ° C. was calculated as CTE (ppm / ° C.).
Device name: TMA4000S manufactured by MAC Science
Sample length: 10mm
Sample width: 2mm
Temperature rise start temperature: 25 ° C
Temperature rise end temperature: 400 ° C
Temperature increase rate: 5 ° C / min
Atmosphere: Argon

<Evaluation of Thin Blade Whetstone> Cutability A 6-inch silicon wafer was diced under the following conditions using a thin blade whetstone processed to an outer diameter of 56 mm and an inner diameter of 19 mm.
Grinding wheel speed: 30,000rpm
Cutting depth: 0.3 mm
Dicing method: Down cut
Grinding fluid: pure water
Number of cutting lines: 10,000 times The silicon wafer obtained was cut to a target size, and the one that could not be cut was marked as x.

<Evaluation of Thin Blade Whetstone> Chipping A 6-inch silicon wafer was diced under the following conditions using a thin blade whetstone processed to an outer diameter of 55.9 mm and an inner diameter of 19.05 mm.
Grinding wheel speed: 30,000rpm
Cutting depth: 0.3 mm
Dicing method: Down cut
Grinding fluid: pure water
Number of cutting lines: 10,000 times The obtained silicon wafer was observed with an optical microscope, and “O” indicates that almost no chipping is observed, and “X” indicates that chipping is observed. Here, chipping means a crack or chip in the cut surface of the silicon wafer.

[Production Examples 1-8]
(Preparation of polyamic acid solutions A1 to A8)
The inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, and then 223 parts by mass of 5-amino-2- (p-aminophenyl) benzoxazole and 4416 parts by mass of N, N-dimethylacetamide were added. After complete dissolution, 217 parts by mass of pyromellitic dianhydride, diamond abrasive grains and / or CBN are added so as to have the amounts shown in Tables 1 and 2 and stirred at a reaction temperature of 25 ° C. for 24 hours. The viscous polyamic acid solutions A1 to A8 were obtained.

[Production Example 9]
(Preparation of polyamic acid solution B)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, 108 parts by mass of phenylenediamine and 4010 parts by mass of N-methyl-2-pyrrolidone were added and completely dissolved, and then diphenyltetracarboxylic When 292.5 parts by mass of acid dianhydride and diamond abrasive grains were added so as to have the amounts shown in Table 2, and stirred at a reaction temperature of 25 ° C. for 12 hours, a brown viscous polyamic acid solution B was obtained.

[Production Example 10]
(Preparation of polyamic acid solution C)
After the inside of the reaction vessel equipped with a nitrogen introduction tube, a thermometer, and a stirring rod was purged with nitrogen, 200 parts by mass of diaminodiphenyl ether and 4170 parts by mass of N-methyl-2-pyrrolidone were added and completely dissolved, and then pyromellitic acid. When 217 parts by mass of dianhydride and diamond abrasive grains were added in the amounts shown in Table 2, and stirred at a reaction temperature of 25 ° C. for 5 hours, a brown viscous polyamic acid solution C was obtained.

(Examples 1-4)
Polyamide acid solutions A3, A4, A6, and A8 were coated on a non-lubricant surface of a polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) using a comma coater and dried at 110 ° C. for 5 minutes. An acid film was obtained. The polyamic acid film was peeled off from the support, and heat treatment was performed at 150 ° C. × 2 minutes, 220 ° C. × 2 minutes, 475 ° C. × 4 minutes to obtain polyimide films 1 to 4 having a thickness of 5 μm. The obtained polyimide film was punched using a Thomson blade in an annular plate shape having an outer diameter of 55.9 mm and an inner diameter of 19.05 mm, and thin blades 1 to 4 were produced.
Table 3 shows the physical property values of the obtained polyimide films 1 to 4 and the evaluation results of the thin blade grindstones 1 to 4. In addition, “impossible” in the table indicates that a film having good quality cannot be obtained, and various physical properties cannot be measured.

(Example 5)
The polyamic acid solution B was coated on a non-lubricant surface of a polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) using a comma coater and dried at 110 ° C. for 5 minutes to obtain a polyamic acid film. The polyamic acid film was peeled from the support, and heat treatment was performed at 150 ° C. × 2 minutes, 220 ° C. × 2 minutes, 460 ° C. × 4 minutes to obtain a polyimide film 5 having a thickness of 5 μm. Further, a thin blade whetstone 5 was created in the same manner as in Example 1.
Table 3 shows the physical property values of the obtained polyimide film 5 and the evaluation results of the thin blade grindstone 5.

(Example 6)
The polyamic acid solution C was coated on a non-lubricant surface of a polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) using a comma coater and dried at 110 ° C. for 5 minutes to obtain a polyamic acid film. The polyamic acid film was peeled from the support, and heat treatment was performed at 150 ° C. × 2 minutes, 220 ° C. × 2 minutes, and 400 ° C. × 4 minutes to obtain a polyimide film 6 having a thickness of 5 μm. Moreover, the thin blade grindstone 6 was created by the same method as Example 1.
Table 3 shows the physical property values of the obtained polyimide film 6 and the evaluation results of the thin blade grindstone 6.

(Example 7)
A polyimide film 7 and a thin blade grindstone 7 were obtained in the same manner as in Example 1 except that the thickness of the polyimide film was 10 μm.
Table 3 shows the physical properties of the obtained polyimide film 7 and the evaluation results of the thin blade grindstone 7.

(Example 8)
A polyimide film 8 and a thin blade whetstone 8 were obtained in the same manner as in Example 1 except that the thickness of the polyimide film was 12.5 μm.
Table 3 shows the physical property values of the obtained polyimide film 8 and the evaluation results of the thin blade grindstone 8.

(Comparative Examples 1-4)
Polyimide films 8 to 11 and thin blade whetstones 8 to 11 were obtained in the same manner as in Example 1 except that the polyamic acid solutions A1, A2, A5, and A7 were used instead of the polyamic acid solution A3.
Table 4 shows the physical properties of the obtained polyimide films 8 to 11 and the evaluation results of the thin blade whetstones 8 to 11. In addition, “impossible” in the table indicates that a film having good quality cannot be obtained, and various physical properties cannot be measured.

(Comparative Example 5)
A polyimide film 12 and a thin blade grindstone 12 were obtained in the same manner as in Example 1 except that the thickness of the polyimide film was 0.5 μm.
Table 4 shows the physical property values of the obtained polyimide film 12 and the evaluation results of the thin blade grindstone 12.

(Comparative Example 6)
A polyimide film 13 and a thin blade grindstone 13 were obtained in the same manner as in Example 1 except that the thickness of the polyimide film was 50 μm.
Table 4 shows the physical property values of the obtained polyimide film 13 and the evaluation results of the thin blade grindstone 13.

    A polyimide film containing abrasive grains made of diamond and / or cubic boron nitride (CBN) having an average particle diameter of 0.1 μm to 10 μm according to the present invention in a range of 5 mass% to 50 mass%, and having a thickness of 1 μm A thin-blade grindstone having a thickness of ˜30 μm, particularly a polyimide film, is a polyimide film which is a diamine having a benzoxazole structure as a residue of pyromellitic acid and an aromatic diamine as a residue of at least an aromatic tetracarboxylic acid, and a surface direction A thin-blade grindstone with a linear expansion coefficient of -10 ppm / ° C. to 20 ppm / ° C. is excellent in polishing and cutting properties, has excellent durability, particularly durability at high temperatures, and has a good balance between rigidity and toughness. This is a thin blade whetstone with little loss, and polishing such as the manufacture of semiconductor devices that dice using this thin blade whetstone It is extremely significant in the fields that are used in thin-blade grindstone during cutting.

Claims (3)

  It is composed of a polyimide film containing diamond and / or cubic boron nitride (CBN) abrasive grains having an average particle diameter of 0.1 μm to 10 μm in a range of 5% by mass to 50% by mass, and a thickness of 1 μm to 30 μm. A thin blade whetstone characterized by having an annular plate shape.   The polyimide film is a polyimide film composed of at least pyromellitic acid as a residue of aromatic tetracarboxylic acids and a diamine having a benzoxazole structure as a residue of aromatic diamines, and has a linear expansion coefficient of −10 ppm in the plane direction The thin-blade grindstone according to claim 1, which is / ° C to 20 ppm / ° C.   A dicing method using the thin blade grindstone according to claim 1.