JP2017108090A - Dicing sheet and method for producing dicing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dicing sheet which can be produced without requiring irradiation with radiation rays, can also suppress occurrence of thread-like cut pieces, and exhibits good expandability.SOLUTION: There is provided a dicing sheet 1 which has a base material film 2 and an adhesive layer 3 laminated on one surface side of the base material film 2, where the base material film 2 includes at least a resin layer 21 positioned at a closest portion to the adhesive layer 3, a melting point of a resin constituting the resin layer 21 is 60°C or higher and 170°C or lower, a difference between the melting point and a fluidization temperature of the resin is 40°C or higher and 190°C or lower, the resin has a plurality of molecular chains containing olefin as a component, and the molecular chains are bonded to each other by a hydrogen bond or an ion bond.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dicing sheet to which the object to be cut is attached when the object to be cut such as a semiconductor wafer is cut and separated into element pieces, and a method for manufacturing the dicing sheet.

  Semiconductor wafers such as silicon and gallium arsenide, substrates such as glass substrates and alumina substrates, and various packages (in this specification, these are collectively referred to as “objects to be cut”) are manufactured in a large diameter state, These are cut and separated (diced) into element pieces (herein referred to as “chips”) and individually separated (picked up), and then transferred to the next process, the mounting process. At this time, an object to be cut such as a semiconductor wafer is attached to a pressure-sensitive adhesive sheet in advance and subjected to dicing, cleaning, drying, expanding, pick-up, and mounting processes.

  The object to be cut attached to the dicing process is opposite to the side where the cutting tool for cutting is close to the dicing sheet for the purpose of ensuring the handleability of the object and chips in the dicing process and the subsequent processes. Affixed in advance to the surface of the workpiece to be cut. In such a dicing sheet, a polyolefin film or a polyvinyl chloride film is usually used as a base film, and an adhesive layer is provided on the base film.

  In general full-cut dicing as a specific method of the dicing process, an object to be cut is cut by a rotating round blade. At this time, not only the article to be cut but also the pressure-sensitive adhesive layer may be cut, and a part of the base film may be cut to ensure that the article to be cut to which the dicing sheet is stuck is cut.

  At this time, the cutting piece which consists of a material which comprises an adhesive layer and a base film generate | occur | produces from a dicing sheet, and the chip | tip obtained may be contaminated by the cutting piece. One form of such a cutting piece is a thread-like cutting piece that adheres on the dicing line or near the cross section of the chip separated by dicing.

  When the chip is sealed with a large amount of the above-mentioned thread-like cutting pieces adhering to the chip, the thread-like cutting pieces adhering to the chip are decomposed by the heat of sealing, and this pyrolyzate destroys the package. Or cause malfunctions in the resulting device. Since this thread-like cutting piece is difficult to remove by washing, the yield of the dicing process is significantly reduced by the generation of the thread-like cutting piece. Therefore, when dicing using a dicing sheet, it is required to prevent the occurrence of thread-like cutting pieces.

  In addition, when dicing a package in which a plurality of chips are sealed with a cured resin as an object to be cut, a dicing blade with a thicker blade width is used than when dicing a semiconductor wafer, and dicing cuts are made. The depth also becomes deeper. For this reason, since the amount of the base film that is cut and removed during dicing increases as compared with the case of the semiconductor wafer, the generation amount of the thread-like cutting pieces also tends to increase.

  For the purpose of suppressing the generation of such cutting pieces, Patent Document 1 discloses an invention in which a polyolefin film irradiated with 1 to 80 Mrad of an electron beam or γ (gamma) ray is used as a base film of a dicing sheet. Is disclosed. In the said invention, it is thought that the bridge | crosslinking by a covalent bond is formed in resin which comprises a base film by irradiation of an electron beam or a gamma ray, and generation | occurrence | production of a cutting piece is suppressed.

Japanese Patent Laid-Open No. 5-21234

  However, in the invention of Patent Document 1, irradiation of radiation such as electron beam or γ-ray is performed after the above resin is once formed into a film, so that the manufacturing process is increased by one, and the manufacturing cost is generally increased. It tends to be higher than the base film. Moreover, since the crystallinity of resin in a base film is lost when irradiated with an electron beam, the solvent resistance of the obtained base film is relatively low.

  Further, in performing the above-described expanding step, the dicing sheet is required to have good expandability. Here, since the base film in which cross-linking by covalent bond is formed by irradiation of radiation as disclosed in Patent Document 1 shows a relatively high elastic modulus, the dicing sheet disclosed in Patent Document 1 is sufficient. Cannot expand.

  The present invention has been made in view of such a situation, and can be manufactured without the need for radiation irradiation, can suppress the generation of thread-like cutting pieces, and has good expandability. It aims at providing the dicing sheet shown.

  In order to achieve the above object, first, the present invention is a dicing sheet comprising a base film and an adhesive layer laminated on one side of the base film, wherein the base film is The pressure-sensitive adhesive layer has at least a resin layer positioned at the nearest position, and the melting point of the resin constituting the resin layer is 60 ° C. or more and 170 ° C. or less, and the difference between the melting point of the resin and the fluidization temperature is Dicing characterized in that it is 40 ° C. or higher and 190 ° C. or lower, and the resin has a plurality of molecular chains containing olefin as a constituent component, and the molecular chains are bonded by hydrogen bonds or ionic bonds. A sheet is provided (Invention 1).

  In the dicing sheet according to the invention (Invention 1), the resin constituting the base film has a plurality of molecular chains containing olefin as a constituent component, and the molecular chains are bonded by hydrogen bonds or ionic bonds. The melting point of the resin and the temperature difference between the melting point and the fluidization temperature are in the above-mentioned range. Thereby, even if frictional heat is generated by dicing, fluidization of the resin hardly occurs. Here, it is considered that the thread-shaped cutting piece is generated by softening the cutting piece by frictional heat generated during dicing and further extending into a thread shape. Therefore, in the dicing sheet, the fluidization of the resin is less likely to occur, and as a result, the generation of thread-like cutting pieces is suppressed. Moreover, since the base film in which the melting point of the resin and the temperature difference are in the above-mentioned range has a relatively low elastic modulus, it exhibits good expandability. Furthermore, the base film in which the melting point of the resin and the temperature difference are within the above ranges can be produced without being irradiated with radiation such as electron beams or γ rays. Therefore, in the said dicing sheet, compared with the dicing sheet manufactured by the method including the process of radiation irradiation, manufacturing cost can be held down.

  In the above invention (Invention 1), the molecular chain has a side chain derived from a polyhydric alcohol compound having two or more hydroxy groups, and contains ethylene and a radically polymerizable acid anhydride as constituent units. The polyhydric alcohol compound is bonded to the ethylene copolymer by an ester bond, and the bond between the molecular chains is the hydroxyl group present in the side chain and the radical polymerizable acid. Between a carboxy group derived from an anhydride, between the hydroxy group present in the side chain and the ester bond, between a carboxy group derived from the radical polymerizable acid anhydride and the ester bond, A small amount between the hydroxy groups present in the side chain, between the carboxy groups derived from the radical polymerizable acid anhydride and between the ester bonds. It is preferably Kutomo in one hydrogen bond (invention 2).

  In the said invention (invention 2), it is preferable that the said resin further contains the reaction accelerator which accelerates | stimulates the hydrogen bond of the said ethylene-type copolymers (invention 3).

  In the said invention (invention 1-3), it is preferable that the tensile elasticity modulus in 23 degreeC of the said resin layer is 30 Mpa or more and 500 Mpa or less (invention 4).

  In the said invention (invention 1-4), it is preferable that the melt flow rate in the temperature of 190 degreeC and the load of 2.16 kg of the said resin is 0.5 g / 10min or more and 10 g / 10min or less (invention 5).

  In the said invention (invention 1-5), it is preferable that the said base film is further equipped with the 2nd resin layer in the position on the opposite side to the said adhesive layer in the said resin layer (invention 6).

  2ndly, this invention is a manufacturing method of the said dicing sheet (invention 1-6), Comprising: The ethylene-type copolymer which contains ethylene and a radically polymerizable acid anhydride as a structural unit, and 2 hydroxy groups in a molecule | numerator Two or more polyhydric alcohol compounds are reacted to obtain an ethylene copolymer having a side chain derived from the polyhydric alcohol compound, and an ethylene copolymer having a side chain derived from the polyhydric alcohol compound. A method for producing a dicing sheet comprising the step of adding a reaction accelerator for promoting hydrogen bonding to a polymer to obtain the resin is provided (Invention 7).

  The dicing sheet according to the present invention can be manufactured without requiring irradiation of radiation, can suppress the generation of thread-like cutting pieces, and exhibits good expandability.

It is sectional drawing of the dicing sheet which concerns on the 1st Embodiment of this invention. It is sectional drawing of the dicing sheet which concerns on the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
1. Dicing Sheet FIG. 1 is a cross-sectional view of a dicing sheet according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of a dicing sheet according to the second embodiment of the present invention. These dicing sheets 1 include a base film 2 and a pressure-sensitive adhesive layer 3 laminated on one side of the base film 2. The dicing sheet according to the present embodiment may be used only for dicing, or may be a dicing / die bonding sheet used also for die bonding.

(1) Base Film In the dicing sheet 1 according to the present embodiment, the base film 2 includes at least the resin layer 21 positioned in the closest position to the pressure-sensitive adhesive layer 3. In particular, in the dicing sheet 1 shown in FIG. 1, the base film 2 is composed only of the resin layer 21. Moreover, in the dicing sheet 1 shown in FIG. 2, the base film 2 is present at the position closest to the pressure-sensitive adhesive layer 3 and the resin layer 21 on the opposite side of the pressure-sensitive adhesive layer 3. A second resin layer 22.

(1-1) Physical Properties of Resin Layer In the dicing sheet 1 according to this embodiment, the melting point of the resin constituting the resin layer 21 is 60 ° C. or higher and 170 ° C. or lower, and the melting point and fluidization temperature of the resin. The difference is 40 ° C. or higher and 190 ° C. or lower.

  If the difference between the melting point of the resin layer 21 and the temperature is within the above-described range, the resin constituting the resin layer 21 has a sufficiently high fluidization temperature accordingly. Thereby, even if frictional heat is generated during dicing, the fluid constituting the resin layer 21 is suppressed from fluidizing due to the frictional heat. As a result, in the dicing sheet 1 according to the present embodiment, generation of thread-like cutting pieces is suppressed. In addition, since the difference between the melting point of the resin layer 21 and the temperature is within the above-described range, the elastic modulus of the resin constituting the resin layer 21 is relatively low. Thereby, the dicing sheet 1 which concerns on this embodiment shows favorable expandability. Furthermore, the base film 2 in which the difference between the melting point of the resin layer 21 and the temperature is in the above-described range can be produced without being irradiated with radiation such as electron beams or γ rays. Thereby, the dicing sheet 1 which concerns on this embodiment can be manufactured at low cost compared with the dicing sheet manufactured by the method including the process of radiation irradiation.

  In the dicing sheet 1 according to this embodiment, the melting point of the resin constituting the resin layer 21 is 60 ° C. or higher, as described above, preferably 70 ° C. or higher, and particularly preferably 80 ° C. or higher. The melting point of the resin is 170 ° C. or lower as described above, preferably 140 ° C. or lower, particularly preferably 120 ° C. or lower. When the melting point is 60 ° C. or higher, the base film 1 is not tacky and does not stick to the roll, so that the base film 1 can be efficiently obtained by extrusion molding. In addition, when the melting point of the resin constituting the resin layer 21 is 60 ° C. or higher, the resin has appropriate crystallinity, thereby making the resin layer 21 excellent in solvent resistance. On the other hand, if the melting point of the resin constituting the resin layer 21 is 170 ° C. or less, the crystallinity of the resin is not excessively high, and the base film 1 can effectively exhibit excellent expandability.

  Moreover, in the dicing sheet 1 according to the present embodiment, the difference between the melting point of the resin constituting the resin layer 21 and the fluidization temperature is 40 ° C. or higher as described above, preferably 50 ° C. or higher, particularly 60. It is preferable that the temperature is not lower than ° C. Further, the difference between the melting point and the fluidization temperature of the resin is 190 ° C. or lower, preferably 135 ° C. or lower, as described above, and particularly preferably 80 ° C. or lower. The effect which suppresses a thread-shaped cutting piece can be favorably acquired because the said difference is 40 degreeC or more. Further, when the difference is 190 ° C. or less, the resin exhibits an appropriate fluidization temperature, and the processability is excellent. For example, when manufacturing the base film 2 using such a resin, it becomes easy to melt the pellet-shaped resin and form it into a sheet. In addition, resin which irradiated with radiations, such as an electron beam or a gamma ray, and formed the crosslinked structure by a covalent bond inside does not show fluidization.

  In the dicing sheet 1 according to the present embodiment, the fluidization temperature of the resin constituting the resin layer 21 is preferably 100 ° C. or higher, particularly preferably 120 ° C. or higher, and more preferably 140 ° C. or higher. Is preferred. The fluidization temperature of the resin is preferably 360 ° C. or less, particularly preferably 275 ° C. or less, and more preferably 200 ° C. or less. When the fluidization temperature of the resin is 100 ° C. or higher, the above-described effect of suppressing the occurrence of the thread-like cutting pieces can be obtained favorably. Further, when the fluidization temperature is 360 ° C. or lower, the processability is excellent.

  In the dicing sheet 1 according to the present embodiment, the tensile elastic modulus at 23 ° C. of the resin layer 21 is preferably 30 MPa or more, particularly preferably 40 MPa or more, and further preferably 50 MPa or more. Further, the tensile elastic modulus is preferably 500 MPa or less, particularly preferably 300 MPa or less, and further preferably 200 MPa or less. When the tensile elastic modulus is 30 MPa or more, the dicing sheet 1 has an appropriate strength and is excellent in mountability. Specifically, the occurrence of slack in the dicing sheet 1 when the dicing sheet 1 is attached to a wafer and a ring frame is suppressed, and the occurrence of errors during conveyance is effectively suppressed. Further, when the tensile elastic modulus is 500 MPa or less, it is avoided that excessive stress is applied to the dicing sheet 1 during the expanding process, and the dicing sheet 1 is not peeled off from the ring frame even during the expanding process. Retained. In addition, the said tensile elasticity modulus was measured based on JISK7127: 1999, and the specific measuring method is as showing to the below-mentioned test method.

  In the dicing sheet 1 according to the present embodiment, the resin constituting the resin layer 21 preferably has a melt flow rate at a temperature of 190 ° C. and a load of 2.16 kg of 0.5 g / 10 min or more, particularly 0.7 g / It is preferably 10 min or more, and more preferably 1 g / 10 min or more. Further, the melt flow rate is preferably 10 g / 10 min or less, particularly preferably 8 g / 10 min or less, and more preferably 7 g / 10 min or less. When the melt flow rate is within the above range, uniform film thickness accuracy can be effectively achieved when the base film 2 including the resin layer 21 is formed by extrusion molding. The melt flow rate is measured at a temperature of 190 ° C. and a load of 2.16 kg in accordance with JIS K7210: 2014.

  When the base film 2 is composed of only the resin layer 21 as shown in FIG. 1, the thickness of the resin layer 21 is preferably 20 μm or more, preferably 40 μm or more, and more preferably 60 μm or more. Preferably there is. Furthermore, the thickness is preferably 600 μm or less, preferably 300 μm or less, and more preferably 200 μm or less. Moreover, when the base film 2 is composed of the resin layer 21 and the second resin layer 22 as shown in FIG. 2, the thickness of only the resin layer 21 is preferably 10 μm or more, and 20 μm or more. It is preferable that the thickness is 30 μm or more. Furthermore, the thickness is preferably 300 μm or less, preferably 120 μm or less, and more preferably 100 μm or less. The thickness of the resin layer 21 is 20 μm or more when the base film 2 is made of only the resin layer 21, and is 10 μm or more when the base film 2 is made of the resin layer 21 and the second resin layer 22. Thus, the effect of suppressing the generation of thread-like cutting pieces can be sufficiently exhibited. Further, the thickness of the resin layer 21 is 600 μm or less when the base film 2 is composed of only the resin layer 21, and is 300 μm or less when the base film 2 is composed of the resin layer 21 and the second resin layer 22. As a result, the dicing sheet 1 can effectively exhibit excellent expandability.

(1-2) Resin Layer Composition The resin constituting the resin layer 21 is a resin having a plurality of molecular chains containing an olefin as a constituent component, and in the resin, the molecular chains are bonded by hydrogen bonds or ionic bonds. doing. The resin can achieve the physical properties described above. In such a resin, molecular chains are constrained by hydrogen bonds or ionic bonds, and thus the fluidization temperature is increased as compared with resins in which molecular chains are not bonded to each other. As a result, the effect of suppressing the occurrence of the thread-like cutting pieces as described above can be favorably obtained. In addition, since the molecular chains are bonded to each other by these bonds, it is not necessary to perform a process such as electron beam irradiation for producing a covalent bond when the base film 2 is manufactured. The increase can be suppressed. In the present specification, the functional group capable of hydrogen bonding is referred to as a hydrogen bonding functional group, and the functional group capable of performing ionic bonding is referred to as an ion bonding functional group.

  Examples of the hydrogen bonding functional group include a functional group containing at least one of a hydrogen atom bonded to an atom having a higher electronegativity (hydrogen bond donor) and an atom having an isolated atom pair (hydrogen bond acceptor). Specific examples include a hydroxy group, a carboxy group, an ester group, an amino group, an amide group, and the like. Examples of the ion-binding functional group include a cationic group and an anionic group. In the molecular chain, the ion-binding functional group may form an ionic bond with other components. For example, the anionic group of the molecular chain is a cationic metal ion. The case where it couple | bonds through is mentioned. In the dicing sheet 1 according to this embodiment, the molecular chains are preferably hydrogen-bonded from the viewpoint that they are superior in solvent resistance. A resin containing a hydrogen bond is expected to be excellent in solvent resistance because it has a lower polarity than a resin containing an ionic bond and has a low affinity for a solvent.

  Examples of more specific resins that can achieve the physical properties described above include ethylene and radical polymerizable acid anhydrides having side chains derived from polyhydric alcohol compounds having two or more hydroxy groups. Examples thereof include a resin containing an ethylene copolymer contained as a unit. Since the ethylene copolymer is not particularly polar, the resin has excellent solvent resistance.

  In the resin, the polyhydric alcohol compound is bonded to the ethylene copolymer by an ester bond between one of its hydroxy groups and the radical polymerizable acid anhydride. The plurality of ethylene copolymers are hydroxy groups present in the side chain (hydroxy groups derived from the polyhydric alcohol compound and not forming the ester bond), radical polymerizability. A hydrogen bond is formed by a carboxy group derived from an acid anhydride and any of the above ester bonds. Specifically, between the hydroxy group present in the side chain and a carboxy group derived from the radical polymerization acid anhydride, between the hydroxy group present in the side chain and the ester bond, the radical polymerization acid. At least one between a carboxy group derived from an anhydride and the ester bond, between a hydroxy group present in the side chain, between a carboxy group derived from the radical polymerizable acid anhydride, and between the ester bonds Are hydrogen bonded. In this resin, the ethylene-based copolymers are constrained by such a pseudo-crosslinked structure due to hydrogen bonding, so that the fluidization temperature is increased as compared with the resin not including the crosslinked structure. It is possible to satisfactorily suppress the generation of a long thread-like cutting piece.

  The resin containing the ethylene polymer preferably further contains a reaction accelerator that promotes hydrogen bonding between the ethylene polymers. The reaction accelerator increases the bonding rate and dissociation rate of hydrogen bonds, so that a reversible phase transition is rapidly performed, and the above-described pseudo cross-linked structure is efficiently formed.

  Examples of radically polymerizable acid anhydrides contained as constituent units in ethylene copolymers include maleic anhydride, itaconic anhydride, citraconic anhydride, endic anhydride, 1-butene-3,4-dicarboxylic anhydride Thing etc. are mentioned. These may be used alone or in combination of two or more. Of these, maleic anhydride is preferably used from the viewpoints of reactivity and economy.

  The content of the radical polymerizable acid anhydride in the ethylene copolymer is preferably 0.1% by mass or more, particularly 0.3% by mass or more, among the constituent units constituting the ethylene copolymer. It is preferable that Further, the content is preferably 20% by mass or less, and particularly preferably 5.0% by mass or less, among the constituent units constituting the ethylene copolymer. When the content is 0.1% by mass or more, the resin constituting the resin layer 21 can be sufficiently hydrogen-bonded, and the effect of suppressing the generation of the above-described thread-like cutting pieces is favorably obtained. be able to. In addition, when the content is 20% by mass or less, hydrogen bonds are generated at an appropriate density, whereby the elastic modulus of the resin layer 21 becomes appropriate, and the dicing sheet 1 exhibits more excellent expandability. To do.

  The ethylene-based copolymer may include a structural unit other than ethylene and a radical polymerizable acid anhydride (hereinafter sometimes referred to as “third monomer”). Thereby, control of melting | fusing point of the resin layer 21, fluidization temperature, a softness | flexibility, etc. becomes easy. Examples of structural units other than ethylene and radical polymerizable acid anhydrides include: ethylenically unsaturated ester compounds, ethylene unsaturated amide compounds, ethylene unsaturated carboxylic acid compounds, ethylene unsaturated ether compounds, ethylene unsaturated A hydrocarbon compound etc. are mentioned.

  More specific examples of the third monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, (meth ) Benzyl acrylate, methyl fumarate, ethyl fumarate, dimethyl maleate, diethyl maleate, vinyl acetate, (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethylacrylamide, (meth) acrylic acid, Examples include fumaric acid, methyl vinyl ether, methyl allyl ether, styrene, butadiene, and acrylonitrile. These may be used alone or in combination of two or more. In addition, “(meth) acrylic acid” in the present specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

  When using the said 3rd monomer, it is preferable that the content is 30 mass% or less among the structural units which comprise an ethylene-type copolymer, and it is especially preferable that it is 25 mass% or less. By being 30 mass% or less, it is suppressed that melting | fusing point of resin falls too much, and the resin layer 21 can exhibit practical heat resistance.

  Examples of the polyhydric alcohol compounds include ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, trimethylolethane, trimethylolpropane, and pentaerythritol. Intramolecular such as arbitol, sorbitol, xylose, glucose, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol, polyolefin oligomer having two or more hydroxyl groups in one molecule, ethylene-hydroxyethyl (meth) acrylate copolymer A polymer having a plurality of hydroxy groups, a polyoxyalkylene compound obtained by adding ethylene oxide or propylene oxide to the alcohol compound as described above, and a polyglycerin ester Etc. The. These may be used alone or in combination of two or more. In addition, the melting point of these polyhydric alcohol compounds is desirably 300 ° C. or less from the viewpoint of easy mixing with other compounds when producing an ethylene-based copolymer.

  The amount of the polyhydric alcohol compound used is preferably such that the molar ratio of the hydroxy group derived from the polyhydric alcohol to the carboxy group derived from the radical polymerizable acid anhydride is 0.01 or more. It is preferable that it is 05 or more. The molar ratio is preferably 10 or less, and particularly preferably 5 or less.

  Examples of the reaction accelerator include a metal salt of a carboxylic acid or a metal salt of a polymer containing a carboxy group. Examples of metal salts of carboxylic acids include acetic acid, butyric acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, succinic acid, benzoic acid, terephthalic acid, pyromellitic acid And a metal salt of a group IA, IIA, IIB, or IIIB element (eg, Li, Na, K, Mg, Ca, Zn, Al, etc.) of the periodic table.

  Examples of metal salts of polymers containing carboxyl groups include some or all of the carboxyl groups of ethylene- (meth) acrylic acid copolymers and elements of groups IA, IIA, IIB, IIIB of the periodic table (For example, a metal salt with Li, Na, K, Mg, Ca, Zn, Al, etc.) or a copolymer of ethylene and an ethylene- (meth) acrylic acid metal salt. Moreover, you may use the 3rd monomer mentioned above as a monomer of the polymer containing a carboxyl group.

  Further, the reaction accelerator may be obtained by graft polymerization of an unsaturated carboxylic acid metal salt to a polyolefin resin such as polyethylene or polypropylene. Other examples of the reaction accelerator include triethylamine, trimethylamine, tetramethylammonium tetrafluoroborate, tetramethylammonium hexafluorophosphate, tetramethylammonium bromide, tetraethylammonium bromide and the like.

  These reaction accelerators may be used alone or in combination of two or more. Of these reaction accelerators, it is preferable to use a carboxylic acid metal salt from the viewpoint of ease of handling and economy.

  Although the usage-amount of a reaction accelerator can be suitably adjusted according to the kind, generally it is 0.001 mass part or more with respect to 100 mass parts of ethylene-type copolymers before side chain introduction | transduction. Particularly preferred is 0.01 parts by mass or more. Moreover, it is preferable that the said usage-amount is 20 mass parts or less, and it is especially preferable that it is 15 mass parts or less.

  The resin layer 21 includes various additives such as pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, fillers, and the like as long as the above-described physical properties relating to the melting point and fluidization temperature are achieved. It may be. Examples of the pigment include titanium dioxide and carbon black. Examples of the filler include organic materials such as melamine resin, inorganic materials such as fumed silica, and metal materials such as nickel particles.

  The surface of the resin layer 21 on the pressure-sensitive adhesive layer 3 side may be subjected to surface treatment such as primer treatment, corona treatment, plasma treatment or the like in order to improve the adhesion with the pressure-sensitive adhesive layer 3. Moreover, when a base film consists only of the resin layer 21, the various coating films may be provided in the surface on the opposite side to the adhesive layer 3 in the resin layer 21. FIG.

(1-3) Second resin layer When the base film 2 includes the second resin layer 22 as shown in FIG. 2, the material constituting the second resin layer 22 is not particularly limited. The resin film used for the base material of a typical dicing sheet can be used. Specific examples of such resin films include ethylene-based copolymer such as ethylene-vinyl acetate copolymer film, ethylene- (meth) acrylic acid copolymer film, and ethylene- (meth) acrylic acid ester copolymer film. Film: Polyethylene film such as polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, ethylene-norbornene copolymer film, norbornene resin film; Polyethylene film such as polyvinyl chloride film, vinyl chloride copolymer film Polyvinyl chloride film; Polyester film such as polyethylene terephthalate film and polybutylene terephthalate film; Polyurethane film; Polyimide film; Polystyrene film; Polycarbonate Bo sulfonate film; and a fluorine resin film. Examples of the polyethylene film include a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, and a high density polyethylene (HDPE) film. In addition, modified films such as these crosslinked films and ionomer films are also used. The base material may be a film made of one of these, or a laminated film in which two or more of these are combined.

  Among the above-mentioned resin films, from the viewpoint of interlayer adhesion, moldability, expandability, and solvent resistance, ethylene copolymer films, particularly ethylene-vinyl acetate copolymer films, ethylene- (meth) acrylic. Acid copolymer film and ethylene- (meth) acrylate copolymer film; polyolefin film, in particular, polyethylene film, polypropylene film, polybutene film, ethylene-norbornene copolymer film and norbornene resin film; polyurethane film; polystyrene It is preferable to use a film or a fluororesin film.

  Similar to the resin layer 21, the second resin layer 22 may contain various additives such as pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, fillers, and the like in addition to the resin. . Various coating films may be provided on the surface of the second resin layer 22 opposite to the pressure-sensitive adhesive layer.

  Although the thickness of the 2nd resin layer 22 is not specifically limited, It is preferable that it is 10 micrometers or more, it is preferable that it is 40 micrometers or more, Furthermore, it is preferable that it is 50 micrometers or more. Furthermore, the thickness is preferably 300 μm or less, preferably 120 μm or less, and more preferably 100 μm or less. When the thickness of the second resin layer 22 is 10 μm or more, the dicing sheet 1 has an appropriate strength, and mountability is improved. When the thickness of the second resin layer 22 is 300 μm or less, the dicing sheet 1 can effectively exhibit excellent expandability.

(1-4) Physical properties, etc. of base film In the dicing sheet 1 according to the present embodiment, the thickness of the base film 2 is not particularly limited, and the thickness is the same as the base film of a general dicing sheet. Can do. For example, as shown in FIG. 1, when the base film 2 is composed only of the resin layer 21, the thickness is preferably 20 μm or more, preferably 40 μm or more, and more preferably 60 μm or more. It is preferable that Furthermore, the thickness is preferably 600 μm or less, preferably 300 μm or less, and more preferably 200 μm or less. As shown in FIG. 2, when the base film 2 is composed of the resin layer 21 and the second resin layer 22, the base film includes both the resin layer 21 and the second resin layer 22. The thickness of 2 is preferably 20 μm or more, preferably 60 μm or more, and more preferably 80 μm or more. Further, the thickness is preferably 600 μm or less, preferably 240 μm or less, and more preferably 200 μm or less.

  When the pressure-sensitive adhesive layer 3 contains an active energy ray-curable pressure-sensitive adhesive and ultraviolet rays are used as energy rays to be irradiated to cure the pressure-sensitive adhesive layer 3, the base film 2 is preferably permeable to ultraviolet rays. . Moreover, when using an electron beam as the said energy beam, it is preferable that the base film 2 has the transparency with respect to an electron beam.

(2) Manufacturing method of base film The base film 2 can be manufactured by a general method. When the resin constituting the resin layer 21 is produced, first, ethylene, a radical polymerizable acid anhydride and, if desired, a third monomer are copolymerized to obtain an ethylene-based copolymer. Next, the side derived from the polyhydric alcohol compound containing the monoester formed from the radical polymerizable acid anhydride and the polyhydric alcohol by reacting the ethylene copolymer with the polyhydric alcohol. An ethylene copolymer having a chain is obtained. Thereby, since a carboxyl group, a hydroxyl group, and an ester bond are introduced into the ethylene-based copolymer, the ethylene-based copolymers form hydrogen bonds between the above-described combinations of these groups and bonds, and Pseudo-crosslinks can be formed. Further, if desired, a reaction accelerator can be mixed with the ethylene copolymer. As a result, the bonding rate and dissociation rate of the hydrogen bond are increased, phase transition is rapidly performed, and the above-described pseudo cross-linked structure is efficiently formed. Subsequently, the resin layer 21 can be formed by molding the resin into a film by a melt extrusion molding method, a calendar method, or the like.

  When using a commercial item as the resin constituting the resin layer 21, the resin layer 21 can be formed by forming the commercial item into a film by a melt extrusion molding method, a calendar method, or the like.

  When the base film 2 includes the second resin layer 22, the base film 2 in which the resin layer 21 and the second resin layer 22 are laminated is obtained by a general coextrusion method or a lamination method. Can do.

(3) Pressure-sensitive adhesive layer The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 3 is not particularly limited, and those usually used as the dicing sheet 1 can be used. For example, rubber-based, acrylic-based, silicone-based, polyvinyl An ether-based pressure-sensitive adhesive is used, and may be an energy ray-curable pressure-sensitive adhesive (including an ultraviolet-curing type) or a heat-curable pressure-sensitive adhesive. In addition, when the dicing sheet 1 in the present embodiment is used as a dicing die bonding sheet, an adhesive, a thermoplastic adhesive, a B stage adhesive, etc. that simultaneously have a wafer fixing function and a die bonding function. Is used.

  The thickness of the pressure-sensitive adhesive layer 3 is not particularly limited, and is preferably, for example, 3 μm or more, and particularly preferably 5 μm or more. Further, the thickness is preferably 100 μm or less, and particularly preferably 80 μm or less.

(4) Release sheet The dicing sheet 1 according to the present embodiment may include a release sheet on the surface of the pressure-sensitive adhesive layer 3 opposite to the base film 2. The release sheet is used to protect the adhesive surface of the adhesive layer 3.

  Examples of release sheets include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane Film, ethylene vinyl acetate film, ionomer resin film, ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Can be used. Moreover, you may use these bridge | crosslinking films. Furthermore, a laminated film in which a plurality of these films are laminated may be used.

  The release surface of the release sheet (the surface in contact with the pressure-sensitive adhesive layer 3) is preferably subjected to a release treatment. Examples of the release agent used for the release treatment include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents.

  The thickness of a peeling sheet is not specifically limited, For example, it is preferable that they are 20 micrometers or more and 150 micrometers or less.

2. Manufacturing method of dicing sheet The manufacturing method of the dicing sheet 1 can be manufactured by a general method except that the base film 2 is manufactured by the method described above.

  For example, first, a coating composition containing a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 and, if desired, a solvent is prepared. Next, this coating agent is applied on the release surface of the release sheet produced as described above by a die coater, curtain coater, spray coater, slit coater, knife coater, and the like, and dried to produce an adhesive layer 3. Can be formed. Then, the dicing sheet 1 is obtained by bonding the surface opposite to the release sheet of the pressure-sensitive adhesive layer 3 and one surface of the base film 2. In addition, when the base film 2 contains the 2nd resin layer 22, the surface at the side of the resin layer 21 of the base film 2 and the adhesive layer 3 are bonded. The properties of the coating agent are not particularly limited as long as it can be applied. The coating agent may contain a component for forming the pressure-sensitive adhesive layer 3 as a solute or a dispersoid.

  As another manufacturing method of the dicing sheet 1, as described above on one surface of the base film 2 (the surface on the resin layer 21 side of the base film 2 when the second resin layer 22 is present). The dicing sheet 1 in which the adhesive layer 3 is formed on the base film 2 can be obtained by applying and drying the coating agent.

  In the dicing sheet 1 manufactured by the method described above, the resins constituting the resin layer 21 are made of ethylene copolymers that are hydrogen-bonded or ion-bonded to each other. Therefore, the ethylene copolymer is moderately restrained, and the fluidization temperature is increased as compared with a resin not subject to such restraint. As a result, it is possible to satisfactorily achieve both the effect of suppressing the generation of the thread-like cutting pieces as described above and the expandability. Further, since the ethylene copolymers are bonded to each other by hydrogen bonds or ionic bonds, it is not necessary to perform a process such as electron beam irradiation for generating a covalent bond, and as a result, an increase in manufacturing cost can be suppressed. .

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, another layer may be interposed between the base film 2 and the pressure-sensitive adhesive layer 3 in the dicing sheet 1.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
1. Production of base film Reaction accelerator for ethylene copolymer having side chain derived from polyhydric alcohol compound having two or more hydroxy groups and containing ethylene and radical polymerizable acid anhydride as constituent unit A thermoplastic resin (melt flow rate at a temperature of 190 ° C. and a load of 2.16 kg: 4 g / 10 min) is extruded with a small T-die extruder (product name “Laboplast Mill” manufactured by Toyo Seiki Seisakusho Co., Ltd.). The base film consisting of a resin layer having a thickness of 80 μm was obtained.

2. Preparation of pressure-sensitive adhesive composition 100 parts by mass of a copolymer (Mw: 500,000) obtained by copolymerizing 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid, and a urethane acrylate oligomer (Mw: 8,000) 120 parts by mass, 5 parts by mass of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane, product name “Coronate L”), and 4 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product name “Irgacure 184”) By mixing, an energy ray curable pressure-sensitive adhesive composition was obtained.

3. Preparation of a dicing sheet Peeling of a release sheet (product name “SP-PET38111 (S)”) obtained by releasing the energy ray-curable pressure-sensitive adhesive composition obtained in Step 2 above with a silicone release agent It apply | coated to the process surface and it was made to dry at 100 degreeC for 1 minute, and the adhesive layer with a film thickness of 10 micrometers was formed. A dicing sheet was obtained by laminating the surface of the pressure-sensitive adhesive layer opposite to the release sheet and one side of the base film obtained in the above step 1.

[Example 2]
A reaction accelerator for an ethylene-based copolymer having a side chain derived from a polyhydric alcohol compound having two or more hydroxy groups as a thermoplastic resin and containing ethylene and a radically polymerizable acid anhydride as a constituent unit A dicing sheet was obtained in the same manner as in Example 1 except that a thermoplastic resin (melt flow rate at a temperature of 190 ° C. and a load of 2.16 kg: 6 g / 10 min) was used.

[Comparative Example 1]
As a thermoplastic resin, a polyethylene resin having a density of 924 kg / m ³ (manufactured by Sumitomo Chemical Co., Ltd., product name “Sumikasen L405”, melt flow rate at a temperature of 190 ° C. and a load of 2.16 kg: 3.7 g / 10 min) is used. In the same manner as in Example 1, a dicing sheet was obtained.

[Comparative Example 2]
As a thermoplastic resin, except that a random copolymer of propylene (manufactured by Prime Polymer Co., Ltd., product name “Prime Polypro F-744NP”, temperature 190 ° C. and melt flow rate at a load 2.16 kg: 7 g / 10 min) is used. A dicing sheet was obtained in the same manner as in Example 1.

[Comparative Example 3]
As in Example 1, except that high-density polyethylene (manufactured by Nippon Polypro Co., Ltd., product name “NOVATEC HY540”, temperature 190 ° C. and melt flow rate at load 2.16 kg: 1 g / 10 min) is used as the thermoplastic resin. To obtain a dicing sheet.

[Comparative Example 4]
As a thermoplastic resin, a high-pressure low-density polyethylene which is an ethylene homopolymer (manufactured by Sumitomo Chemical Co., Ltd., product name “Sumikasen F101-1”, melt flow rate at a temperature of 190 ° C. and a load of 2.16 kg: 0.3 g / 10 min) A dicing sheet was obtained in the same manner as in Example 1 except that was used.

[Comparative Example 5]
As in Example 1, except that low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name “Sumikasen G801”, melt flow rate at a temperature of 190 ° C. and a load of 2.16 kg: 20 g / 10 min) is used as the thermoplastic resin. To obtain a dicing sheet.

[Comparative Example 6]
Example 1 with the exception of using a polypropylene-based elastomer (product name “Toughmer PN2070”, temperature 190 ° C. and melt flow rate: 3.2 g / 10 min at a load of 2.16 kg) as the thermoplastic resin. A dicing sheet was obtained in the same manner.

[Comparative Example 7]
Example except that ethylene-α-olefin (manufactured by Mitsui Chemicals, product name “Tuffmer 4070S”, temperature 190 ° C. and melt flow rate at a load of 2.16 kg: 3.6 g / 10 min) is used as the thermoplastic resin. A dicing sheet was obtained in the same manner as in 1.

[Comparative Example 8]
Implemented except using poly-4-methyl-1-pentene (product name “TPX MX002”, temperature 190 ° C. and melt flow rate at load 2.16 kg: 0 g / 10 min) as the thermoplastic resin A dicing sheet was obtained in the same manner as in Example 1.

[Test Example 1] (Measurement of tensile modulus)
The base film obtained in Examples and Comparative Examples was cut into 15 mm × 140 mm test pieces, and the tensile elastic modulus was measured according to JIS K7127: 1999. Specifically, the test piece was set to a distance between chucks of 100 mm with a tensile tester (manufactured by Shimadzu Corporation, product name “Autograph AG-IS 500N”), and then subjected to a tensile test at a speed of 200 mm / min. The tensile modulus (MPa) was measured. The results are shown in Table 1. However, in the case where the base film could not be formed satisfactorily and the tensile modulus could not be measured, “-” was displayed in Table 1.

[Test Example 2] (Measurement of melting point)
The melting points of the thermoplastic resins used in the examples and comparative examples were measured using a differential scanning calorimeter (DSC, manufactured by DS Instruments, product name “Q2000”) according to JIS K7121.

[Test Example 3] (Measurement of fluidization temperature)
The fluidization temperature of the thermoplastic resin used in Examples and Comparative Examples was measured using a descent type flow tester (manufactured by Shimadzu Corporation, model number “CFT-100D”). Using a die with a load of 5.0 N, a hole shape of φ2.0 mm, and a length of 5.0 mm, and increasing the temperature of the measurement sample at a temperature increase rate of 10 ° C./min, the stroke displacement rate that varies with the temperature increase (Mm / min) was measured to obtain a temperature dependence chart of the stroke displacement speed of the sample. From the temperature dependence chart, the temperature at which the stroke displacement speed starts increasing again after the passage of the peak obtained beyond the softening point was defined as the fluidization temperature. The results are shown in Table 1.

  Further, the temperature difference ΔT (° C.) was calculated by subtracting the melting point value obtained in Test Example 2 from the obtained fluidization temperature value. The values are shown in Table 1.

[Test Example 4] (Evaluation of film forming property)
(1) Production of two types and two layers of base film Each resin used in Examples and Comparative Examples and low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name “Sumikasen L705”, temperature 190 ° C. and load 2. The melt flow rate at 16 kg: 7.0 g / 10 min) was adjusted to a ratio of 5: 5 by a feed block method, and a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name “Laboplast”). A base film composed of two types and two resin layers having a thickness of 80 μm was obtained.
(2) Evaluation About the single layer base film manufactured in the Example and the comparative example, and the two types and two layers of base film manufactured in the above (1), the film forming property for each example and comparative example was evaluated. . Specifically, the samples for which the evaluation samples for both the single layer and the two types and two layers were successfully produced were ○, the thickness accuracy was unstable, the die line was confirmed, the base film was What was not able to produce any one or both samples of a film, such as being taken by the cooling roll, was evaluated as x. The results are shown in Table 1.

[Test Example 5] (Evaluation of cutting piece)
For the dicing sheets of Examples and Comparative Examples in which the film forming property was evaluated as “good” in Test Example 4, the adhesive layer was attached to a silicon wafer, and then a dicing apparatus (manufactured by DISCO, product name “DFD-651”) And dicing was performed under the following conditions.
・ Work (adherence): Silicon wafer ・ Work size: 6 inches, thickness 0.35mm
・ Dicing blade: manufactured by Disco Corporation, product name “27HEEE”
・ Blade rotation speed: 50,000rpm
・ Dicing speed: 10 mm / second ・ Depth of cut: Cut from the base film surface to a depth of 25 μm ・ Dicing size: 5 mm × 5 mm

Then, the ultraviolet-ray was irradiated from the base film side (light quantity: 160mJ / cm < ² >), and the cut | disconnected chip | tip was peeled from the dicing sheet. Among vertical and horizontal dicing lines, the number of thread-like cutting pieces generated on one vertical line and one horizontal line near the center of each was measured using a digital microscope (manufactured by Keyence Corporation, product name “VHX-100”, magnification) : 100 times). Then, the evaluation was made with 0 to 10 thread-like cutting pieces and X to 11 or more cutting pieces. The results are shown in Table 1.

[Test Example 6] (Evaluation of mountability)
Regarding the dicing sheets of Examples and Comparative Examples in which the film forming property was evaluated as good in Test Example 4, a 6-inch wafer was attached to the adhesive layer, and then the dicing sheet was mounted on a flat frame. Thereafter, when the flat frame was lifted parallel to the ground, the dicing sheet did not sag, and the sagging occurred as x. The results are shown in Table 1.

[Test Example 7] (Evaluation of expandability)
With respect to the dicing sheets of Examples and Comparative Examples in which the mount suitability was evaluated as “good” in Test Example 6, dicing was performed using the same apparatus as in Test Example 4 under the same conditions.

Then, the ultraviolet-ray was irradiated from the base film side (light quantity: 160mJ / cm < ² >). Subsequently, using an expanding jig (manufactured by NEC Machinery, product name “Die Bonder CSP-1000VX”), the dicing sheet was pulled down 20 mm at a speed of 2 mm / sec. At that time, the dicing sheet is not torn or the dicing sheet is not peeled off from the frame, and the one that can be expanded without any problems is marked as ◯, and the dicing sheet is torn or the dicing sheet is peeled off from the frame × It was evaluated. The results are shown in Table 1.

[Test Example 8] (Evaluation of solvent resistance)
About the Example and comparative example by which the film forming property was evaluated as (circle) in the said test example 4, the butyl acetate was dripped on the base film obtained by these Examples and comparative examples. After leaving at room temperature for 10 minutes, the case where nothing occurred was marked with ◯, and the case where swelling occurred was marked with ×. The results are shown in Table 1.

  As can be seen from Table 1, the dicing sheets produced in the examples hardly formed thread-like cut pieces and exhibited excellent expandability. Further, the dicing sheets produced in the examples were excellent in film forming properties, mountability and solvent resistance.

  The dicing sheet according to the present invention is suitably used for dicing semiconductor wafers and various packages.

DESCRIPTION OF SYMBOLS 1 ... Dicing sheet 2 ... Base film 21 ... Resin layer 22 ... 2nd resin layer 3 ... Adhesive layer

Claims (7)

A dicing sheet comprising a base film and an adhesive layer laminated on one side of the base film,
The base film is provided with at least a resin layer located in the closest position to the pressure-sensitive adhesive layer;
The melting point of the resin constituting the resin layer is 60 ° C. or higher and 170 ° C. or lower,
The difference between the melting point of the resin and the fluidization temperature is 40 ° C. or more and 190 ° C. or less,
The resin has a plurality of molecular chains containing olefin as a constituent component,
The dicing sheet, wherein the molecular chains are bonded by hydrogen bonds or ionic bonds. The molecular chain is an ethylene copolymer having a side chain derived from a polyhydric alcohol compound having two or more hydroxy groups and containing ethylene and a radically polymerizable acid anhydride as constituent units,
The polyhydric alcohol compound is bonded to the ethylene copolymer by an ester bond,
The bond between the molecular chains is between the hydroxy group present in the side chain and the carboxy group derived from the radical polymerizable acid anhydride, and between the hydroxy group present in the side chain and the ester bond. Between the carboxy group derived from the radical polymerizable acid anhydride and the ester bond, between the hydroxy groups present in the side chain, between the carboxy group derived from the radical polymerizable acid anhydride and The dicing sheet according to claim 1, wherein the dicing sheet is a hydrogen bond in at least one of the ester bonds.   The dicing sheet according to claim 2, wherein the resin further includes a reaction accelerator that promotes hydrogen bonding between the ethylene copolymers.   The dicing sheet according to any one of claims 1 to 3, wherein the resin layer has a tensile elastic modulus at 23 ° C of 30 MPa or more and 500 MPa or less.   The dicing sheet according to any one of claims 1 to 4, wherein a melt flow rate of the resin at a temperature of 190 ° C and a load of 2.16 kg is 0.5 g / 10 min or more and 10 g / 10 min or less. .   The dicing sheet according to claim 1, wherein the base film further includes a second resin layer at a position opposite to the pressure-sensitive adhesive layer in the resin layer. It is a manufacturing method of the dicing sheet according to any one of claims 1 to 6,
A side chain derived from the polyhydric alcohol compound by reacting an ethylene copolymer containing ethylene and a radical polymerizable acid anhydride as a structural unit with a polyhydric alcohol compound having two or more hydroxy groups in the molecule. And a step of obtaining a resin by adding a reaction accelerator for promoting hydrogen bonding to an ethylene copolymer having a side chain derived from the polyhydric alcohol compound. The manufacturing method of the dicing sheet characterized by including these.

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