JP2009158503A - Tape for processing wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tape for processing a wafer which suppresses chipping of a chip side face and burrs of an adhesive layer during dicing, and having excellent strippability when picking up thin film chips. <P>SOLUTION: An intermediate resin layer 2, a pressure sensitive adhesive layer 3, and an adhesive layer 4 are laminated in this order on a base material film 1 to form this tape 10 for processing the wafer. The intermediate resin layer 2 is harder than the pressure sensitive adhesive layer 3, and the thicknesses of the intermediate layer 2 and the pressure sensitive adhesive layer 3 are less than 10 μm respectively, and the total thickness of the intermediate resin layer 2 and the pressure sensitive adhesive layer 3 is less than 15 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wafer processing tape used for processing a semiconductor wafer or the like, and more specifically, a dicing tape used in a wafer dicing process, and a chip diced with the dicing process. The present invention relates to a dicing die bonding tape used in a mounting process for bonding to a lead frame or another chip.

  In the manufacturing process of a semiconductor device such as an IC, after attaching a stretchable adhesive tape to the back surface of the semiconductor wafer, the process of cutting and separating (dicing) the semiconductor wafer after pattern formation into individual chips was performed. A step of picking up a chip and a step of bonding the picked-up chip to a lead frame, a package substrate, or the like, or a stacked package is performed in which semiconductor chips are stacked and bonded together.

  As a pressure-sensitive adhesive tape used in the manufacturing process of the semiconductor device, in addition to a dicing tape in which a pressure-sensitive adhesive layer is provided on a base film, a pressure-sensitive adhesive layer and an adhesive layer are laminated in this order on the base film.・ Die bonding tape has been proposed and already put into practical use.

The dicing tape is a process for dicing a semiconductor wafer, which fixes the wafer so that the cut chips do not scatter, and requires high adhesive strength to firmly fix the wafer. Is required to be easily peeled off.
On the other hand, the dicing die bonding tape has a function as a dicing tape and a die bonding film (also referred to as a die attach film) in addition to the function of the dicing tape. It is picked up with the chip in a state where it is peeled from the agent layer and attached to the back surface of the chip. By using such a dicing die bonding tape, it is possible to mount a chip with an adhesive layer directly on a lead frame, a package substrate, etc. The step of bonding can be omitted.

  In the dicing step, the dicing blade cuts up to a part of the adhesive layer or a part of the substrate film along the chip shape. However, the adhesive layer used in dicing die bonding tape contains a lot of low molecular weight substances such as epoxy resin, and it is softer and more machinable than the adhesive layer used in general dicing tape. There is a tendency to be inferior. Therefore, burrs of the adhesive layer occur during dicing. Such burr of the adhesive layer causes a pickup failure in the pickup process after dicing, a chip adhesion failure in the mounting process, and the like, and decreases the yield of the semiconductor device.

In order to solve the above problem, for example, Patent Document 1 discloses a wafer processing tape in which an intermediate resin layer having a larger storage elastic modulus than the pressure-sensitive adhesive layer is provided between the base film and the pressure-sensitive adhesive layer. It is disclosed.
JP 2006-49509 A

In Patent Document 1, by providing an intermediate resin layer having a larger storage elastic modulus than the pressure-sensitive adhesive layer between the base film and the pressure-sensitive adhesive layer, chip side cracks and cracking (chipping) can be suppressed. In addition, it is described that there is little beard-like cutting waste during dicing, and good machinability of the adhesive layer can be obtained. Patent Document 1 describes that when a wafer having a thickness of 100 μm is diced and picked up, a pickup success rate of 100% can be achieved.
However, in recent years, with the miniaturization and thinning of semiconductor devices, thinning of wafers to be diced has progressed, and the thickness thereof has increased to 50 μm or less, making it difficult to peel off chips from tape. Therefore, further improvement of the peelability at the time of pick-up is required for the wafer processing tape.

  Accordingly, an object of the present invention is to provide a wafer processing tape that suppresses chipping on the side surface of a chip during dicing and generation of burrs on an adhesive layer and is excellent in releasability when a thin film chip is picked up.

  The inventors have provided an intermediate resin layer harder than the adhesive layer between the base film and the adhesive layer, the intermediate resin layer and the adhesive layer have a thickness of less than 10 μm, respectively, and the intermediate resin layer By setting the total thickness of the adhesive layer and the pressure-sensitive adhesive layer to less than 15 μm, it is possible to suppress chipping on the side surface of the chip during dicing and generation of burrs on the adhesive layer and to pick up a thin film chip of 50 μm or less well. I found it. The present invention has been completed based on this finding.

  A first aspect of the present invention is a wafer processing tape in which an intermediate resin layer and an adhesive layer are laminated in this order on a base film, the intermediate resin layer being harder than the adhesive layer, A wafer processing tape, wherein the thickness of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 10 μm, respectively, and the total thickness of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 15 μm. is there.

  According to a second aspect of the present invention, in the wafer processing tape according to the first aspect, an adhesive layer is further provided on the pressure-sensitive adhesive layer.

  According to a third aspect of the present invention, in the wafer processing tape according to the first or second aspect, each of the intermediate resin layer and the adhesive layer has a thickness of less than 7 μm, and the intermediate resin layer The adhesive layer has a total thickness of less than 14 μm.

  According to a fourth aspect of the present invention, in the wafer processing tape according to the third aspect, a total thickness of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 10 μm.

  According to a fifth aspect of the present invention, in the wafer processing tape according to the fourth aspect, each of the intermediate resin layer and the pressure-sensitive adhesive layer has a thickness of less than 5 μm.

  According to a sixth aspect of the present invention, in the wafer processing tape according to any one of the first to fifth aspects, the thickness of the intermediate resin layer is larger than the pressure-sensitive adhesive layer.

According to a seventh aspect of the present invention, in the wafer processing tape according to any one of the first to sixth aspects, a storage elastic modulus at 80 ° C. of the intermediate resin layer is 5 × 10 ⁴ to 1 × 10 ^7. It is in the range of Pa.

According to an eighth aspect of the present invention, in the wafer processing tape according to any one of the first to seventh aspects, a storage elastic modulus at 25 ° C. of the intermediate resin layer is 5 × 10 ⁴ to 1 × 10 ^7. It is in the range of Pa.

  According to a ninth aspect of the present invention, in the wafer processing tape according to any one of the first to eighth aspects, the intermediate resin layer is an acrylic resin having a three-dimensional network structure. .

  According to a tenth aspect of the present invention, in the wafer processing tape according to any one of the first to ninth aspects, the intermediate resin layer is a thermosetting resin.

  An eleventh aspect of the present invention is the wafer processing tape according to any one of the first to tenth aspects, wherein the pressure-sensitive adhesive layer is a radiation-curable carbon having an iodine value of 0.5 to 20 in the molecule. It contains a compound (A) having a carbon double bond and at least one compound (B) selected from polyisocyanates, melamine / formaldehyde resins and epoxy resins.

  The wafer processing tape of the present invention is excellent in releasability required at the time of picking up a thin film chip, and can suppress and prevent chip side chipping and adhesive layer burr generated during wafer dicing.

Embodiments of the present invention will be described below.
1 and 2 show two examples of the wafer processing tape of the present invention. FIG. 1 shows a dicing die bonding tape 10 in which an intermediate resin layer 2, an adhesive layer 3, and an adhesive layer 4 are laminated on a base film 1, and FIG. 2 shows an intermediate resin on the base film 1. A dicing tape 20 in which the layer 2 and the pressure-sensitive adhesive layer 3 are laminated. 1 and 2 show a state in which the semiconductor wafer W and the dicing ring frame 12 are bonded to the wafer processing tape.

  Each layer may be cut (precut) into a predetermined shape in advance in accordance with the use process and apparatus. Further, the dicing die bonding tape 10 and the dicing tape 20 before the wafer W is bonded may be provided with a cover film for protecting the adhesive layer 4 or the pressure-sensitive adhesive layer 3. Further, the wafer processing tape of the present invention includes a form cut for each wafer and a form obtained by winding a plurality of long sheets formed in a roll shape.

1 and FIG. 2, the thickness of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 is less than 10 μm, respectively, and the total thickness of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 is set to be less than 15 μm. Is done. By setting the thickness of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 in such a range, excellent releasability is exhibited when picking up a thin film chip. More preferably, the thickness of each of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 is less than 7 μm, and the total thickness of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 is less than 14 μm. More preferably, the thickness of each of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 is less than 7 μm, and the total thickness of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 is less than 10 μm. Even more preferably, the thicknesses of the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 are each less than 5 μm. From the viewpoint of suppressing chipping on the side surface of the chip, the thickness of the intermediate resin layer 2 is preferably larger than that of the pressure-sensitive adhesive layer 3.
The intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 may have a structure in which a plurality of layers are laminated.
Next, the structure of a base film and each layer is demonstrated in order.

(Base film)
The base film which comprises the dicing die-bonding tape 10 and the dicing tape 20 of this invention is demonstrated.
The base film is not particularly limited, and known plastics, rubbers and the like can be used. In general, a thermoplastic plastic film is used as the base film. It is preferable that it is radiation transmissive. In particular, when a radiation curable pressure sensitive adhesive is used for the pressure sensitive adhesive layer, it is necessary to select a material having good radiation transparency at a wavelength at which the pressure sensitive adhesive is cured. Examples of polymers that can be selected as such a substrate include polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-acrylic. Homopolymer or copolymer of α-olefin such as ethyl acid copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, ionomer, or a mixture thereof, polyethylene terephthalate, polycarbonate, polymethyl methacrylate Engineering plastics such as polyurethane, thermoplastic elastomers such as polyurethane, styrene-ethylene-butene or pentene copolymers, polyamide-polyol copolymers, and mixtures thereof. Moreover, you may use what made these two or more layers.

  In order to increase the gap between the semiconductor chips, it is preferable that necking (occurrence of partial elongation due to poor propagation of force that occurs when the base film is stretched radially) is as small as possible, including polyurethane, molecular weight and styrene. Examples thereof include styrene-ethylene-butene or pentene copolymers with limited amounts, and it is effective to use a cross-linked substrate film to prevent elongation or deflection during dicing.

  The surface of the base film on the side on which the intermediate resin layer is provided may be appropriately subjected to treatment such as corona treatment or provision of a primer layer in order to improve the adhesion with the intermediate resin layer.

  The thickness of the substrate film is usually suitably from 30 to 300 μm from the viewpoint of strong elongation characteristics and radiation transparency. In addition, the base material by reducing the friction between the adhesive tape and the jig at the time of radial stretching of the adhesive tape by applying a texture or lubricant coating on the surface of the base film on which the adhesive layer is not applied. Effects such as prevention of necking of the film are obtained, which is preferable.

(Intermediate resin layer)
The intermediate resin layer 2 constituting the dicing die bonding tape 10 and the dicing tape 20 of the present invention is harder than the pressure-sensitive adhesive layer 3 described later, that is, the storage elastic modulus at room temperature or 80 ° C. is the pressure-sensitive adhesive layer 3. As long as it is higher than that, there is no particular limitation. In order to suppress chip cracking and chipping (chipping) during dicing, the preferred range of the storage elastic modulus at 80 ° C. or 25 ° C. of the intermediate resin layer 2 is 5 × 10 ⁴ to 1 × 10 ⁷ Pa, and more It is preferably 1 × 10 ^{5 to} 5 × 10 ⁶ Pa.

  In particular, when the dicing die bonding tape 10 shown in FIG. 1 is used, by providing the intermediate resin layer 2 that is harder than the pressure-sensitive adhesive layer 3 in this way, the flexible fluid having high fluidity through the pressure-sensitive adhesive layer 3. Since the hard intermediate resin layer 2 is present under the adhesive layer 4, the machinability of the adhesive layer 4 during dicing is improved, and the occurrence of burrs in the adhesive layer can be suppressed.

  The intermediate resin layer can be formed by coating a mixture containing an adhesive component and a curing component on a base film and then curing the mixture. For the intermediate resin layer, it is preferable to use a material that is gradually cured by leaving it to stand at room temperature for about one week and has an elastic modulus in a preferable range.

  Methods for hardening the intermediate resin layer include increasing the glass transition point (Tg) of the adhesive component used as the main component, adding a large amount of curing agent added to the intermediate resin layer, or adding an inorganic compound filler. However, it is not limited to this method. Alternatively, a material that is cured by radiation irradiation may be used, and the hardness of the intermediate resin layer may be adjusted by curing by radiation irradiation. Here, the radiation is a general term for ionizing radiation such as light such as ultraviolet rays, laser light, or electron beams. (Hereafter referred to as radiation.)

  As the adhesive component, various general-purpose adhesives such as acrylic, polyester, urethane, silicone, and natural rubber can be used. In the present invention, an acrylic adhesive is particularly preferable. Examples of the acrylic pressure-sensitive adhesive include (meth) acrylic acid ester copolymers composed of structural units derived from (meth) acrylic acid ester monomers and (meth) acrylic acid derivatives. Here, as the (meth) acrylic acid ester monomer, (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, and (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl group are used. . Examples of the (meth) acrylic acid derivative include glycidyl (meth) acrylate having a glycidyl group, and hydroxyethyl acrylate having a hydroxyl group.

  The curing agent is a compound selected from polyisocyanates, melamine / formaldehyde resins, and epoxy resins, and can be used alone or in combination of two or more. This curing agent acts as a cross-linking agent, and the intermediate resin layer has a three-dimensional network structure due to the cross-linking structure formed as a result of reacting with an adhesive component such as an acrylic resin, and is difficult to soften even when the temperature rises due to dicing or the like. .

  The polyisocyanates are not particularly limited, and examples thereof include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4 ′-[2,2-bis (4 -Phenoxyphenyl) propane] aromatic isocyanate such as diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate Lysine diisocyanate, lysine triisocyanate and the like. Specifically, Coronate L etc. can be used as a commercial item.

As the melamine / formaldehyde resin, for example, Nicalac MX-45 (manufactured by Sanwa Chemical Co., Ltd.), melan (manufactured by Hitachi Chemical Co., Ltd.), or the like can be used.
Furthermore, as an epoxy resin, TETRAD-X (made by Mitsubishi Chemical Corporation) etc. can be used, for example.
In the present invention, it is particularly preferable to use polyisocyanates.

Furthermore, by providing the intermediate resin layer with radiation curability, the chip pick-up property of the chip may be improved by curing and shrinking the intermediate resin layer by radiation curing after dicing.
In order to impart radiation curability, for example, an acrylate oligomer having a photopolymerizable carbon-carbon double bond may be added. As these oligomers, low molecular weight compounds having at least two photopolymerizable carbon-carbon double bonds in a molecule that can be three-dimensionally reticulated by light irradiation are widely used. Specifically, trimethylolpropane triacrylate, Tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1,6 hexanediol diacrylate, polyethylene glycol di Acrylate and oligoester acrylate are widely applicable.

  In addition to the above acrylate compounds, urethane acrylate oligomers can also be used. The urethane acrylate oligomer includes a polyol compound such as a polyester type or a polyether type, and a polyvalent isocyanate compound (for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diene). A terminal isocyanate urethane prepolymer obtained by reacting isocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.) with an acrylate or methacrylate having a hydroxyl group (for example, 2-hydroxyethyl) Acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, etc.) It is obtained by reacting.

  When the intermediate resin layer is polymerized by radiation, a photopolymerization initiator such as isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler's ketone, chlorothioxanthone, benzyl methyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethyl phenyl Propane etc. can be used together. By adding at least one of these to the intermediate resin layer, the polymerization reaction can proceed efficiently.

  Further, the intermediate resin layer may contain a tackifier, a tackifier, a surfactant, or other modifiers as necessary.

  Thus, the cured intermediate resin layer applied to the base material is a thermosetting resin, and good machinability is obtained without being rapidly softened even near the dicing temperature.

(Adhesive layer)
The dicing tape 20 shown in FIG. 1 is obtained by forming the intermediate resin layer 2 on the base film 1 and further forming the pressure-sensitive adhesive layer 3 on the intermediate resin layer 2.
The pressure-sensitive adhesive layer 3 may be formed by applying a pressure-sensitive adhesive on the intermediate resin layer 2 formed on the base film 1 in the same manner as a normal dicing tape. However, if the intermediate resin layer 2 is one whose storage elastic modulus is adjusted by radiation irradiation, the intermediate resin layer 2 needs to be coated after being cured by radiation. It is.

  The pressure-sensitive adhesive layer 3 constituting the dicing die-bonding tape 10 and the dicing tape 20 of the present invention is not particularly limited, and retainability that does not cause defects such as chip jumping with the adhesive layer during dicing, and pickup It may be sufficient if it has a characteristic that it can be easily peeled off from the adhesive layer. In order to improve the pick-up property of the chip after dicing, the pressure-sensitive adhesive layer is preferably radiation-curable, and in particular, the dicing die bonding tape 10 is preferably a material that can be easily separated from the adhesive layer. .

  Examples of such an adhesive layer include a compound (A) having a radiation curable carbon-carbon double bond having an iodine value of 0.5 to 20 in the molecule, polyisocyanates, melamine / formaldehyde resin, and epoxy. An acrylic pressure-sensitive adhesive containing a compound (B) selected from resins can be used.

  The compound (A) that is one of the main components of the pressure-sensitive adhesive layer will be described. A preferable introduction amount of the radiation curable carbon-carbon double bond of the compound (A) is 0.5 to 20, more preferably 0.8 to 10 in terms of iodine value. When the iodine value is 0.5 or more, an effect of reducing the adhesive strength after radiation irradiation can be obtained. If the iodine value is 20 or less, the flowability of the pressure-sensitive adhesive after irradiation is sufficient, so that a sufficient chip gap can be obtained when expanding the wafer processing tape after wafer dicing. The image recognizability of each chip can be improved. Furthermore, the compound (A) itself is stable and easy to manufacture.

The compound (A) preferably has a glass transition point of −70 ° C. to 0 ° C., more preferably −66 ° C. to −28 ° C. If the glass transition point (hereinafter referred to as Tg) is −70 ° C. or higher, the heat resistance against heat accompanying radiation irradiation is sufficient, and if it is 0 ° C. or lower, the element after dicing on a wafer having a rough surface state A sufficient scattering prevention effect can be obtained.
The compound (A) may be produced by any method, and has, for example, a radiation curable carbon-carbon double bond such as an acrylic copolymer or a methacrylic copolymer, and a functional group. A compound obtained by reacting a compound having the functional group ((1)) with a compound having a functional group capable of reacting with the functional group ((2)) is used.

  Among these, the compound ((1)) having a radiation curable carbon-carbon double bond and a functional group is a single compound having a radiation curable carbon-carbon double bond such as an acrylic acid alkyl ester or a methacrylic acid alkyl ester. It can be obtained by copolymerizing a monomer ((1) -1) and a monomer having a functional group ((1) -2).

As a monomer ((1) -1), C6-C12 hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, decyl acrylate, or a single quantity having 5 or less carbon atoms The pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or methacrylates similar to these can be listed.
As the monomer ((1) -1) is used, the glass transition point becomes lower as the monomer having a larger carbon number is used, so that the desired glass transition point can be produced. In addition to the glass transition point, a monomer ((1) -1) may be blended with a low molecular compound having a carbon-carbon double bond such as vinyl acetate, styrene, or acrylonitrile for the purpose of improving compatibility and various performances. ) In the range of 5% by mass or less of the total mass.

  Examples of the functional group of the monomer ((1) -2) include a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group. The monomer ((1)- Specific examples of 2) include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, glycol monoacrylates, glycol monomethacrylates. N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride, Phthalic anhydride, glycidyl acrylate, It can be enumerated those urethanization a monomer having a carbon-carbon double bond and - glycidyl methacrylate, allyl glycidyl ether, a portion of the isocyanate groups of the polyisocyanate compound a hydroxyl group or a carboxyl group and a radiation-curable carbon.

In the compound ((2)), the functional group used is a compound ((1)), that is, when the functional group of the monomer ((1) -2) is a carboxyl group or a cyclic acid anhydride group. Can include a hydroxyl group, an epoxy group, an isocyanate group, and in the case of a hydroxyl group, it can include a cyclic acid anhydride group, an isocyanate group, and the like, and in the case of an amino group, an epoxy group, an isocyanate group In the case of an epoxy group, a carboxyl group, a cyclic acid anhydride group, an amino group, and the like can be exemplified. Specific examples of the monomer ((1) -2) The same thing as what was enumerated by can be enumerated.
By leaving an unreacted functional group in the reaction of the compound ((1)) and the compound ((2)), it is possible to produce those specified in the present invention with respect to characteristics such as acid value or hydroxyl value.

  In the synthesis of the above compound (A), as the organic solvent when the reaction is carried out by solution polymerization, ketone, ester, alcohol, and aromatic solvents can be used, among which toluene, ethyl acetate , Isopropyl alcohol, benzene methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, etc., are generally good solvents for acrylic polymers and preferably have a boiling point of 60-120 ° C. The polymerization initiator is α, α′-azobisisobutyl. A radical generator such as an azobis type such as nitrile or an organic peroxide type such as benzoyl peroxide is usually used. At this time, a catalyst and a polymerization inhibitor can be used together as necessary, and the compound (A) having a desired molecular weight can be obtained by adjusting the polymerization temperature and the polymerization time. In terms of adjusting the molecular weight, it is preferable to use a mercaptan or carbon tetrachloride solvent. This reaction is not limited to solution polymerization, and other methods such as bulk polymerization and suspension polymerization may be used.

As described above, the compound (A) can be obtained. In the present invention, the molecular weight of the compound (A) is preferably about 300,000 to 1,000,000. If it is less than 300,000, the cohesive force due to radiation irradiation becomes small, and when the wafer is diced, the device is likely to be displaced, and image recognition may be difficult. In order to prevent the deviation of the element as much as possible, the molecular weight is preferably 400,000 or more. Further, if the molecular weight exceeds 1,000,000, there is a possibility of gelation at the time of synthesis and coating.
In addition, it is preferable that the compound (A) has an OH group having a hydroxyl value of 5 to 100 because the risk of pick-up mistakes can be further reduced by reducing the adhesive strength after radiation irradiation. Moreover, it is preferable that a compound (A) has a COOH group used as the acid value of 0.5-30.

Here, if the hydroxyl value of the compound (A) is too low, the effect of reducing the adhesive strength after irradiation is not sufficient, and if it is too high, the fluidity of the adhesive after irradiation tends to be impaired. If the acid value is too low, the effect of improving the tape restoring property is not sufficient, and if it is too high, the fluidity of the pressure-sensitive adhesive tends to be impaired.
The iodine value was calculated based on the Das method under the reaction conditions of 40 ° C. for 24 hours, and the molecular weight was determined by gel permeation chromatography (Waters Corporation) using a 1% solution obtained by dissolving in tetrahydrofuran. The value measured by a product name, 150-C ALC / GPC) is calculated as the weight average molecular weight in terms of polystyrene. The hydroxyl value is calculated by the FT-IR method, and the acid value is calculated in accordance with 11.1 of JIS K 5407.

  Next, the compound (B) which is another main component of the pressure-sensitive adhesive layer will be described. The compound (B) is a compound selected from polyisocyanates, melamine / formaldehyde resins, and epoxy resins, and can be used alone or in combination of two or more. This compound (B) acts as a cross-linking agent, and the cross-linking structure formed as a result of reacting with the compound (A) or the base film causes the cohesive strength of the pressure-sensitive adhesive mainly composed of the compounds (A) and (B) to It can be improved after application.

  The polyisocyanates are not particularly limited, and examples thereof include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4 ′-[2,2-bis (4 -Phenoxyphenyl) propane] aromatic isocyanate such as diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate Lysine diisocyanate, lysine triisocyanate and the like. Specifically, Coronate L etc. can be used as a commercial item.

Further, as the melamine / formaldehyde resin, specifically, Nicalac MX-45 (manufactured by Sanwa Chemical Co., Ltd.), Melan (manufactured by Hitachi Chemical Co., Ltd.), etc. can be used as commercial products.
Furthermore, TETRAD-X (made by Mitsubishi Chemical Corporation) etc. can be used as an epoxy resin.
In the present invention, it is particularly preferable to use polyisocyanates.

  As addition amount of (B), it is preferable to set it as 0.1-10 mass parts with respect to 100 mass parts of compounds (A), and it is more preferable to set it as 0.4-3 mass parts. If the amount is less than 0.1 parts by mass, the effect of improving the cohesive force tends to be insufficient. If the amount exceeds 10 parts by mass, the curing reaction proceeds rapidly during the formulation and application of the adhesive, and a crosslinked structure is formed. Therefore, workability tends to be impaired.

  Moreover, in this invention, it is preferable that the photoinitiator (C) is contained in the adhesive layer. There is no restriction | limiting in particular in the photoinitiator (C) in which an adhesive layer is contained, A conventionally well-known thing can be used. For example, benzophenones such as benzophenone, 4,4′-dimethylaminobenzophenone, 4,4′-diethylaminobenzophenone and 4,4′-dichlorobenzophenone, acetophenones such as acetophenone and diethoxyacetophenone, 2-ethylanthraquinone, t- Examples include anthraquinones such as butylanthraquinone, 2-chlorothioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzyl, 2,4,5-triarylimidazole dimer (lophine dimer), acridine compounds, and the like. These can be used alone or in combination of two or more.

  As addition amount of (C), it is preferable to set it as 0.1-10 mass parts with respect to 100 mass parts of compounds (A), and it is more preferable to set it as 0.5-5 mass parts.

  Furthermore, the radiation-curable pressure-sensitive adhesive used in the present invention can be blended with a tackifier, a pressure-adjusting agent, a surfactant, or other modifiers as necessary. Moreover, you may add an inorganic compound filler suitably.

(Adhesive layer)
The dicing die bonding tape 20 shown in FIG. 2 is obtained by further forming the adhesive layer 4 on the dicing tape 10 shown in FIG.
The adhesive layer is an adhesive used to fix the chip to the substrate or lead frame by peeling off the adhesive layer and adhering to the back of the chip when the chip is picked up after the wafer W is bonded and diced. It is what is used. Although it does not specifically limit as the adhesive bond layer 3, What is necessary is just a film adhesive generally used for a dicing die-bonding tape, and an acrylic adhesive, epoxy resin / phenol resin / An acrylic resin blend adhesive is preferred. The thickness may be appropriately set, but is preferably about 5 to 100 μm.

  As the adhesive layer 3 of the dicing die bonding tape 10 of the present invention, the adhesive layer 3 previously formed into a film (hereinafter referred to as an adhesive film) is used as the intermediate resin layer 2 and the pressure-sensitive adhesive layer 3 described above. It can be formed by laminating on the pressure-sensitive adhesive layer surface of the dicing tape of the present invention formed on the base film 1. It is preferable to apply a linear pressure of 0.1 to 100 kgf / cm at a laminating temperature of 10 to 100 ° C. In addition, the adhesive film may be formed on the separator, and the separator may be peeled off after lamination, or it may be used as a cover film for dicing die bonding tape and peeled off when the wafer is bonded. Also good. Moreover, although an adhesive film may be laminated | stacked on the whole surface of the adhesive layer 3, you may laminate | stack the adhesive film cut | disconnected (pre-cut) in the shape according to the wafer bonded together. When the adhesive film according to the wafer is laminated, when using the dicing die bonding tape of the present invention, the portion to which the wafer is bonded has an adhesive layer, and the dicing ring frame is bonded to the portion to be bonded. Is used without being bonded to an adhesive layer. In general, since the adhesive layer is difficult to peel off from the adherend, adhesive residue is likely to occur on the ring frame or the like. By using the pre-cut adhesive film, the ring frame can be bonded to the pressure-sensitive adhesive layer, and the effect of hardly causing adhesive residue on the ring frame when the tape is peeled after use can be obtained.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

  The intermediate resin layer composition, the pressure-sensitive adhesive layer composition, and the adhesive film are prepared as described below, and the dry film thickness of the intermediate resin layer composition is shown in Table 1 as an ethylene-vinyl acetate copolymer film having a thickness of 100 μm. It was coated to a thickness and dried at 110 ° C. for 3 minutes. Further, the pressure-sensitive adhesive layer composition was coated so that the dry film thickness was as shown in Table 1, and dried at 110 ° C. for 3 minutes. A tape was prepared. Adhesive films are bonded onto the adhesive layer of these adhesive tapes, and the dicing die bonding tapes of Examples 1 to 6 and Comparative Examples 1 to 4 as shown in Tables 1 and 2 are prepared, and the characteristics are evaluated. It was.

<Preparation of intermediate resin layer composition>
(Intermediate resin layer composition 1A)
Intermediate resin by mixing 100 parts by mass of acrylic resin (mass average molecular weight: 730,000, glass transition temperature −24 ° C.) and 10 parts by mass of polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate L) as a curing agent. A layer composition 1A was obtained.

(Intermediate resin layer composition 1B)
Radiation curing by mixing 100 parts by mass of acrylic resin (mass average molecular weight: 800,000, glass transition temperature -7 ° C.) and 10 parts by mass of a polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate L) as a curing agent. Intermediate resin layer composition 1C was obtained.

<Preparation of adhesive layer composition>
(Adhesive composition 2A)
In 400 g of toluene as a solvent, 128 g of n-butyl acrylate, 307 g of 2-ethylhexyl acrylate, 67 g of methyl methacrylate, 1.5 g of methacrylic acid, and a mixed solution of benzoyl peroxide as a polymerization initiator are appropriately adjusted in a dropping amount, and reacted. The temperature and reaction time were adjusted to obtain a solution of compound (1) having a functional group.
Next, 2.5 g of 2-hydroxyethyl methacrylate synthesized separately from methacrylic acid and ethylene glycol as a compound (2) having a radiation curable carbon-carbon double bond and a functional group was added to this polymer solution, and hydroquinone as a polymerization inhibitor. A solution of the compound (A) having a radiation curable carbon-carbon double bond having an iodine value, a molecular weight, and a glass transition point shown in Table 1 by appropriately adjusting the dropping amount and adjusting the reaction temperature and reaction time. Got. Subsequently, 100 parts by mass of the compound (A) in the compound (A) solution is made by Nippon Polyurethane Co., Ltd. as a polyisocyanate (B): 1 part by mass of Coronate L is added, and Nihon Ciba Geigy Co., Ltd. is used as a photopolymerization initiator: A radiation-curable pressure-sensitive adhesive composition 2A was prepared by adding 0.5 parts by mass of Irgacure 184 and 150 parts by mass of ethyl acetate as a solvent to the compound (A) solution and mixing them.

(Adhesive composition 2B)
100 parts by mass of acrylic resin (mass average molecular weight: 610,000, glass transition temperature −22 ° C.) and 10 parts by mass of polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate L) as a curing agent Composition 2B was obtained.

<Preparation of adhesive film>
(Adhesive film 3A)
50 parts by mass of a cresol novolac type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) as an epoxy resin, 1.5 parts by mass of γ-mercaptopropyltrimethoxysilane as a silane coupling agent, γ-ureidopropyltriethoxysilane Cyclohexanone was added to a composition consisting of 3 parts by mass and 30 parts by mass of silica filler having an average particle size of 16 nm, and the mixture was stirred and mixed, and further kneaded for 90 minutes using a bead mill.

To this, 100 parts by mass of acrylic resin (mass average molecular weight: 800,000, glass transition temperature-17 ° C), 5 parts of dipentaerythritol hexaacrylate as a hexafunctional acrylate monomer, 0.5 part of an adduct of hexamethylene diisocyanate as a curing agent, 2.5 parts of Curesol 2PZ (trade name: 2-phenylimidazole, manufactured by Shikoku Kasei Co., Ltd.) was added, mixed with stirring, and vacuum degassed to obtain an adhesive.
Adhesive is applied onto a 25 μm thick release-treated polyethylene terephthalate film, heated and dried at 110 ° C. for 1 minute to form a B-stage coating film with a thickness of 40 μm, and an adhesive with a carrier film Film 3A was produced.

<Characteristic evaluation>
The dicing die bonding tapes of Examples 1 to 6 and Comparative Examples 1 to 4 as shown in Table 1 were prepared, and the elasticity of the adhesive layer at an elastic modulus of 80 ° C. at 25 ° C. and 80 ° C. of the intermediate resin layer. Evaluation of the rate, chip surface, adhesive burr presence, side chipping average (μm), and pickup success rate characteristics were performed as follows.

(Elastic modulus)
The elastic modulus at 25 ° C. or 80 ° C. of the intermediate resin layer and the pressure-sensitive adhesive layer was measured from 0 ° C. using a viscoelasticity meter (manufactured by Rheometric Science Co., Ltd., trade name: ARES), and the heating rate was 5 ° C. The dynamic viscoelasticity was measured at a frequency of 1 Hz per minute, and the storage elastic modulus G ′ when the temperature reached 25 ° C. or 80 ° C. was defined as the respective elastic modulus.
Moreover, what passed 14 days after preparation was used for the intermediate | middle resin layer and adhesive layer which are measured.

(With or without adhesive burr)
A silicon wafer having a thickness of 50 μm and a diameter of 200 mm was heated and bonded to the dicing die bonding tape obtained in Examples and Comparative Examples at 70 ° C. for 10 seconds, and then a dicing apparatus (manufactured by DISCO, trade name: DAD340) was used. Dicing was performed to 5 mm × 5 mm at a rotation speed of 40000 rpm and a cutting speed of 100 mm / sec. Thereafter, for 20 chips at the center of the silicon wafer, the presence or absence of burrs in the adhesive on the side surface of the chip to which the die bond agent was transferred was examined by microscopic observation.

(Side chipping)
As an evaluation of chipping / cracking (chipping) during dicing, side chipping was measured as follows.
A silicon wafer having a thickness of 50 μm and a diameter of 200 mm was heated and bonded at 70 ° C. for 10 seconds to the dicing die bonding tape obtained in the examples and comparative examples, and then a dicing apparatus (trade name: DAD340, manufactured by DISCO Corporation) was used. Dicing was performed to 5 mm × 5 mm at a rotation speed of 40000 rpm and a cutting speed of 100 mm / sec. Then, dicing to 5 mm × 5 mm, observing the chip after dicing, measuring the chipping size (size from the end of the chip) generated on the side surface of the chip with respect to 50 chips at the center of the silicon wafer, and averaging Values were determined as side chipping values.

(Pickup property)
A silicon wafer having a thickness of 50 μm was bonded by heating at 70 ° C. for 10 seconds to the dicing die bonding tape obtained in Examples and Comparative Examples, and then diced to 10 mm × 10 mm. Thereafter, the pressure-sensitive adhesive layer was irradiated with 200 mJ / cm 2 of ultraviolet light by an air-cooled high-pressure mercury lamp (80 W / cm, irradiation distance 10 cm), and then a die bonder device (manufactured by NEC Machinery, trade name: CPS-) for 50 chips in the center of the silicon wafer. 100FM), and the pickup success rate for each pickup chip was determined. At that time, the pick-up success rate was calculated by assuming that the picked-up element had the adhesive layer peeled off from the adhesive layer and that the pick-up was successful. The pickup properties were ranked as follows.

Pickup success rate with push-up pins of 0.7mm, 0.5mm, and 0.3mm is 100% success rate ... ◎
Pickup success rate at 0.5mm push-up height and 0.5mm is 100%, and pick-up success rate at push-up height 0.3mm is less than 100%.
Pickup success rate at a push-up height of 0.7 mm is 100%, and pick-up success rate at a push-up height of 0.5 mm and 0.3 mm is less than 100%.
Pickup success rate at push-up heights of 0.7 mm, 0.5 mm, and 0.3 mm is less than 100 ... ×

  The elastic modulus of the intermediate resin layer at 80 ° C. and 25 ° C. in each example and comparative example, the elastic modulus of the pressure-sensitive adhesive layer at 80 ° C., chip surface, presence or absence of adhesive burrs, average value of side chipping (μm) The pickup properties are summarized in Tables 1 and 2.

In Comparative Examples 1 and 2, since the thickness of the intermediate resin layer and the pressure-sensitive adhesive is 10 μm or more, the pickup property of the thin film chip is inferior. In particular, in Comparative Example 2, since the intermediate resin layer was softer than the pressure-sensitive adhesive layer, an adhesive burr was also generated.
In Comparative Examples 3 and 4, since there was no intermediate resin layer, burrs of the adhesive occurred during dicing.
On the other hand, in Examples 1 to 6, the chip side surface during dicing and the generation of burrs on the adhesive layer were suppressed, and the thin film chip was successfully picked up.

It is sectional drawing which shows the state by which the semiconductor wafer and the dicing ring frame were bonded together on the wafer processing tape concerning embodiment of this invention. It is sectional drawing which shows the state by which the semiconductor wafer and the ring frame for dicing were bonded together on the tape for wafer processing concerning other embodiment of this invention.

Explanation of symbols

1: base film 2: intermediate resin layer 3: pressure-sensitive adhesive layer 4: adhesive layer 10: dicing die bonding tape 12: dicing ring frame 20: dicing tape

Claims (11)

A wafer processing tape in which an intermediate resin layer and an adhesive layer are laminated in this order on a base film,
The intermediate resin layer is harder than the adhesive layer,
The wafer processing tape, wherein the intermediate resin layer and the pressure-sensitive adhesive layer each have a thickness of less than 10 μm, and the total thickness of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 15 μm. .   The wafer processing tape according to claim 1, further comprising an adhesive layer on the pressure-sensitive adhesive layer.   The thickness of each of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 7 μm, and the total thickness of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 14 μm. Item 3. A wafer processing tape according to Item 2.   The wafer processing tape according to claim 3, wherein the total thickness of the intermediate resin layer and the pressure-sensitive adhesive layer is less than 10 μm.   The wafer processing tape according to claim 4, wherein each of the intermediate resin layer and the pressure-sensitive adhesive layer has a thickness of less than 5 μm.   The wafer processing tape according to claim 1, wherein a thickness of the intermediate resin layer is larger than that of the pressure-sensitive adhesive layer. The storage elastic modulus at 80 ° C. of the intermediate resin layer is in the range of 5 × 10 ⁴ to 1 × 10 ⁷ Pa. 7. For wafer processing according to claim 1, tape. The storage elastic modulus at 25 ° C. of the intermediate resin layer is in the range of 5 × 10 ⁴ to 1 × 10 ⁷ Pa. 8. tape.   The wafer processing tape according to any one of claims 1 to 8, wherein the intermediate resin layer is an acrylic resin having a three-dimensional network structure.   The tape for wafer processing according to any one of claims 1 to 9, wherein the intermediate resin layer is a thermosetting resin. The pressure-sensitive adhesive layer is at least one selected from a compound (A) having a radiation curable carbon-carbon double bond having an iodine value of 0.5 to 20 in the molecule, a polyisocyanate, a melamine / formaldehyde resin, and an epoxy resin. The wafer processing tape according to claim 1, further comprising a compound (B) to be produced.

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