JP2006186305A - Dicing/die bonding tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dicing/die bonding tape which is suitable for preventing the occurrence of chipping and for satisfying the requirements regarding compact packages. <P>SOLUTION: A dicing/die bonding tape has an adhesive layer that is directly or indirectly formed on one side of a base film. When light is radiated from the base film with the adhesive layer peeled off, the total light transmittance at 355 nm is 70% or more, and the parallel light transmittance is 30% or more. The other side of the base film opposite to the side provided with the adhesive layer has a surface roughness Ra of 0.5 μm or less. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dicing die-bonding tape used when a wafer with an adhesive is divided into chips in the form of chips by tip dicing and laser dicing.

  In recent years, the need for miniaturization of mounted components has further increased, and the miniaturization technology for semiconductor packaging has been evolving. As a result, semiconductor chips are also required to be made thinner and smaller, and at the same time, technical needs for compact packaging of these thin and small semiconductor chips will continue to increase. Conventionally, these semiconductor chips are obtained by forming a semiconductor wafer that has been ground and thinned in the back grinding process into a chip in the dicing process. Further, a necessary amount of a liquid adhesive is applied to a continuously flowing lead frame for each die bonding by a pick-up die bonder or the like, and the resulting semiconductor chip is die-bonded at that position.

Among these steps, in a dicing step (see FIG. 8), a dicing tape 6 is bonded to a semiconductor wafer (hereinafter sometimes simply referred to as a wafer) 1, fixed to a chuck table 7 of a dicer with a ring frame 3, and The wafer 2 is cut, but at this time, since the cutting resistance of the wafer 1 is applied to the wafer 1, a small chip is not formed in the singulated semiconductor chip (hereinafter sometimes simply referred to as a chip) 1 ′. And cracks (hereinafter referred to as chipping) may occur. This occurrence of chipping has recently been regarded as one of the important problems, and various studies have been made to reduce chipping so far, but there is still no satisfactory means.
Furthermore, this chipping tends to occur as the thickness of the wafer 1 decreases, and the allowable level of chipping becomes stricter with a small chip. Therefore, as described above, as the tendency of the semiconductor chip to become thinner and smaller is further advanced, it is easily assumed that this chipping problem will become more serious in the future.

Furthermore, as shown in FIG. 9, the separated semiconductor chip 1 ′ is required to be compactly packaged while preventing chipping. This comes from the need to reduce the package size, and it is desired that the package is desirably made to be approximately the same size as the size of the semiconductor chip. Usually, the separated semiconductor chip 1 ′ is die-bonded to the die pad 10 of the lead frame 11 to which the liquid adhesive 8 is applied by a pick-up die bonder or the like. The required application amount is very difficult to control, and furthermore, since it is liquid, the dimensions when applied onto the die pad 10 tend to vary.
In this case, the size of the separated semiconductor chip 1 ′ and the size of the liquid adhesive 8 do not match. Therefore, in packaging, the difference in size between the two is taken into consideration, and the separated semiconductor chip 1 is taken into consideration. It needs to be packaged with dimensions slightly larger than '. As described above, this is not a desirable method because it needs to be packaged with a size almost the same as the size of the semiconductor chip.

On the other hand, there is a method of using a die bond sheet (sheet-like adhesive) as an adhesive for die bonding.
As a method of using this die bond sheet, there is a widely known method in which a small piece of a die bond sheet having the same dimensions as a semiconductor chip is prepared and mounted in advance on a lead frame, or attached to the back surface of each chip one by one. It has been. However, in this case, the work is very complicated and undesirable, and in addition, a small deviation may occur when a small piece of the die bond sheet is attached to the lead frame or the back surface of the chip, which is desirable for these reasons. It's not a method.

Further, as shown in FIG. 10, a die bond film 12 is bonded in advance to the back surface of the semiconductor wafer 1, and then this is bonded to a dicing tape 6, and supported and fixed to a chuck table 7 of a dicer by a ring frame 3. There is a method of full-cutting the semiconductor wafer 1 and the die bond film 12 simultaneously with a cut dicing apparatus.
In this method, the dimensions of the diced semiconductor chip 1 'and the diced die bond film piece 12' are completely the same, and the two are bonded together without any deviation. Can be made. However, in this case, not only the dicing tape 6 but also the die-bonding film 12 is interposed between the two below the semiconductor wafer 1, so that the cutting resistance applied from the blade 2 during dicing causes the wafer 1 or chip 1 'to Compared to the case where there is no die bond film 12, it becomes easier to cause blurring, so that chipping is likely to occur remarkably, and this is a problem.

There has been proposed a method for solving the above-described requirements for preventing chipping and compact packaging (for example, see Patent Document 1).
What is proposed here is that after forming grooves with a depth of cut shallower than the wafer thickness along the scribe line of the semiconductor wafer, the back surface of the wafer is ground while the pattern surface is protected with a protective tape, and the wafer thickness is The dicing die bond sheet consisting of the base material and the adhesive layer (die bond sheet) formed on the ground surface is attached to the ground surface, and the protective tape is peeled off. In this method, the adhesive layer exposed between the chips is cut using a dicing blade, and the chip and the adhesive layer are peeled off from the substrate.
In this method, since the chips are individually divided by backside grinding in the back grinding process, it can be said that this method has a certain effect in preventing the occurrence of chipping.
Japanese Patent Laid-Open No. 2001-156027

However, in this method, when the adhesive layer exposed between the chips is cut using a dicing blade as shown in FIG. 11 (a), the groove between the chips and the dicing blade are accurately aligned. Is very difficult, and there is a high possibility that chipping will occur due to the blade contacting the side surface of the chip as shown in FIG.
The width of the dicing blade used in cutting the adhesive layer is narrower than the groove width between the chips, and the dicing blade width is preferably about 30 to 90% of the groove width between the chips. In this case, the adhesive layer piece formed on the back surface of the chip often becomes larger than the size of the chip (FIGS. 12 and 13).
Therefore, it cannot be said that it is a satisfactory means considering the necessity of packaging with the same size as the size of the semiconductor chip. Therefore, the object of the present invention is suitable for satisfying both the prevention of chipping and the requirement of a compact package. An object of the present invention is to provide a dicing die bond tape.

As a result of intensive studies in view of the above problems, the present inventors have found that the following dicing die-bonding tape is suitable for the purpose.
That is, the present invention
(1) In a dicing die-bonding tape in which an adhesive layer is directly or indirectly formed on a base film, the total light transmittance at 355 nm when the adhesive layer is peeled off and irradiated with light from the base film Is 70% or more and the parallel light transmittance is 30% or more, and the surface roughness Ra of the base film opposite to the surface on which the adhesive layer is provided is 0.5 μm or less. Dicing die bond tape, characterized by
(2) The dicing die-bonding tape according to (1), wherein the base film is a polyolefin film,
(3) A layer in contact with the base film layer among the adhesive layers is provided with a pressure-sensitive adhesive layer, and the adhesive layer is laminated directly or indirectly on the pressure-sensitive adhesive layer (1) or (2) Dicing die bond tape as described,
(4) The pressure-sensitive adhesive layer is selected from polyisocyanates, melamine / formaldehyde resins, and epoxy resins for the compound (A) having a radiation curable carbon-carbon double bond having an iodine value of 0.5 to 20 in the molecule. A dicing die-bonding tape according to (3), which contains a polymer obtained by addition-reacting at least one compound (B).
(5) A dicing die-bonding tape that is fixed to a dicing frame at the time of dicing to manufacture a semiconductor device, and is used in an adhering process for fixing and dicing the wafer, and further superimposing it on a lead frame or a semiconductor chip. The dicing die-bonding tape according to (3) or (4), wherein the portion bonded to the dicing frame has no adhesive layer,
(6) The dicing die-bonding tape according to any one of (3) to (5), wherein the adhesive layer has a pressure-sensitive adhesive layer having a thickness of 5 μm or less.
Is to provide.

  Since the base film of the die bond dicing tape applied to the method of the present invention has good laser transparency, it is possible to cut the adhesive layer by applying a laser from the base film side. The adhesive layer can be diced to the same size, and a compact package can be made without deteriorating the chipping quality by the tip dicing method.

A preferred embodiment in which the die bond dicing tape of the present invention is used will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.
(A) First, the portion of the surface of the semiconductor wafer 1 (see FIG. 1 (a)) where the chip-to-chip penetration is planned is shallower than the wafer thickness, about the final product thickness of the semiconductor wafer, or more A cut groove 13 is formed deeply (see FIG. 1B). [Grooving process]
The cut of the cut groove 13 is performed by appropriately adjusting the cut depth by a widely used blade dicing apparatus. The thickness of the wafer 1 is not limited, and is usually about 300 to 700 μm, and the depth of the cut groove 13 is preferably the same as the thickness of the target chip. It is appropriately set deeper and is generally about 20 to 200 μm.
(B) Next, a surface protection tape 16 composed of an adhesive layer 14 and a base film 15 is applied to the surface of the grooved semiconductor wafer 1 for surface protection (see FIG. 2 (a)). ). [Protective adhesive tape bonding process]
(C) With the surface protective tape 16 applied, the grooved portion of the penetrating portion is completely opened, and the back surface of the wafer substrate is ground until it penetrates, and the film is thinned into individual pieces. The semiconductor chip 1 'is divided (see FIG. 2B). [Thinning process]
(D) After the back surface grinding of the semiconductor wafer substrate is completed, the dicing die bond tape 18 of the present invention is bonded to the back surface side of the semiconductor wafer while the surface protective tape is bonded (see FIG. 4). [Dicing die bond tape bonding process]
(E) Next, in a state where the ring frame 3 is supported and fixed, the dicing die bond tape is irradiated with a laser along a penetrating portion opened by laser dicing to divide the die bond film 12 into chips. [Cutting process]

  The dicing die-bonding tape of the present invention has a total light transmittance when an adhesive layer is formed directly or indirectly on a base film, and the adhesive layer is peeled off and irradiated with light having a wavelength of 355 nm from the base film. Is 70% or more and the parallel light transmittance is 30% or more, and the surface roughness Ra of the base film opposite to the surface on which the adhesive layer is provided is 0.5 μm or less. FIG. 4 shows a dicing die-bonding tape in which the pressure-sensitive adhesive layer 4 is laminated on the base film 17 and further provided with an adhesive layer 12 that is a die-bonding film. The layer may have both functions of an adhesive layer and an adhesive layer. In the present invention, in the latter case, a laminate of the dicing tape pressure-sensitive adhesive layer 4 and the adhesive layer 12 which is a die bond film is referred to as an adhesive layer.

  That is, the dicing die-bonding tape of the present invention peels off the adhesive layer 12 which is a die-bonding film in the former case in which the adhesive layer and the adhesive layer are sequentially provided on the base film as shown in FIG. In the latter case, the adhesive layer having the functions of the pressure-sensitive adhesive layer and the adhesive layer is peeled off, and the adhesive layer having both functions is peeled off. Light is irradiated from the side of the base film opposite to the side on which the agent layer is formed. In this case, the total light transmittance at a wavelength of 355 nm is 70% or more and the parallel light transmittance is 30% or more, and the surface roughness of the base film opposite to the surface on which the adhesive layer is provided is Ra is 0.5 μm or less.

The dicing die-bonding tape of the present invention may be cut (pre-cut) into a predetermined shape in advance according to the use process or apparatus, and the dicing die-bonding tape or dicing tape before the wafer is bonded is an adhesive layer or an adhesive. In order to protect the agent layer, a cover film or a separator film may be provided.
In the dicing ring frame portion, the pressure-sensitive adhesive layer is only formed on the base film, but the book in which the adhesive layer is formed on the pressure-sensitive adhesive layer only in the semiconductor wafer bonding portion inside the ring frame. The dicing die-bonding tape of the invention may be used, and in that case, the adhesive layer is only bonded to the ring frame, and the effect of hardly causing adhesive residue on the ring frame when the tape is peeled off after use is obtained.

Next, the configuration of the dicing die bond tape of the present invention will be described in order.
(Base film)
The base film which comprises the dicing die-bonding tape of this invention is demonstrated. In the present invention, when the adhesive layer is peeled off and the substrate film is irradiated with light, the total light transmittance at 355 nm is 70% or more and the parallel light transmittance is 30% or more. The surface roughness Ra on the side opposite to the surface on which the adhesive layer is provided in the film is 0.5 μm or less, and the substrate film is selected so as to satisfy this condition.
Among them, polyolefin is preferable, and among polyolefins, polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer are preferable. A polymer, an ethylene-methyl acrylate copolymer, an ethylene-acrylic acid copolymer, and an ionomer are preferable.
Furthermore, 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. The

  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. Homopolymers or copolymers of α-olefins such as ethyl acid copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, ionomer or mixtures thereof, polyurethane, styrene-ethylene-butene or Listed are thermoplastic elastomers such as pentene copolymers and polyamide-polyol copolymers, and mixtures thereof. Moreover, you may use what made these two or more layers.

  In order to increase the gap between elements, 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. Polyurethane, molecular weight and styrene content Styrene-ethylene-butene or pentene copolymer, etc., which are limited to the above, can be exemplified, and it is effective to use a cross-linked base film in order to prevent elongation or deflection during dicing.

  Furthermore, in order to improve the adhesiveness with the pressure-sensitive adhesive layer, the surface of the base film may be appropriately subjected to a treatment such as a corona treatment or a primer 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, surface roughness Ra of the surface by which the adhesive layer of a base film is not apply | coated is 0.5 micrometer or less. This is because the scattering of light is suppressed, the parallel light transmittance is increased, and the processing of the adhesive layer is facilitated by laser dicing. Therefore, the closer the surface roughness is to 0 μm, the better. A preferable range of Ra is 0.3 μm or less. In that case, it is preferable not to roughen the surface of the back surface on the side opposite to the adhesive layer provided on the base film by means of embossing or the like.

(Adhesive layer)
As described above, the dicing die-bonding tape of the present invention is manufactured by forming the adhesive layer on the base film. Hereinafter, the case where the adhesive layer in which the pressure-sensitive adhesive and the adhesive are sequentially formed on the base film is made of a laminated type will be described.

(Adhesive layer)
The dicing die-bonding tape of the present invention may be produced by forming a pressure-sensitive adhesive layer on a base film, and applying the pressure-sensitive adhesive on the base film.
In the present invention, the total light transmittance at a wavelength of 355 nm from the base film side is 70% or more, and the parallel light transmittance is 30% or more.
In order to improve the workability of the adhesive layer by laser dicing, it is preferable to increase the total light transmittance and parallel light transmittance at a wavelength of 355 nm from the base film side. The closer to 100%, the better. Therefore, particularly preferably, the total light transmittance is 80% or more and the parallel light transmittance is 40% or more. Within this range, there is an effect that the processability of the adhesive layer by laser dicing becomes good.
As long as this condition is satisfied, there is no particular limitation, and the laser dicing has a property that does not cause a defect such as chip peeling from the adhesive layer, and has characteristics that the adhesive layer can be easily peeled off at the time of pickup. I just need it. In order to improve the pick-up property after dicing, the pressure-sensitive adhesive layer is preferably radiation-curable, and particularly in the case of a dicing die-bonding tape in which a pressure-sensitive adhesive and an adhesive are laminated, peeling from the adhesive layer is easy. A material is preferred.

  For example, in the pressure-sensitive adhesive of the present invention, 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 It is preferable to contain a polymer obtained by subjecting at least one compound (B) selected from the above to addition reaction.

  The compound (A) that is one of the main components of the polymer contained in 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. If the iodine value is 0.5 or more, an effect of reducing the adhesive strength after irradiation can be obtained. If the iodine value is 20 or less, the fluidity of the adhesive after irradiation is sufficient and after stretching. Therefore, the problem that the image recognition of each element becomes difficult at the time of pick-up can be suppressed. 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 (1) having a functional group with a compound (2) having a functional group capable of reacting with the functional group is used.

Among these, the compound (1) having the radiation curable carbon-carbon double bond and the functional group is a monomer having a radiation curable carbon-carbon double bond such as an alkyl acrylate ester or an alkyl methacrylate ester. It can be obtained by copolymerizing ((1) -1) and a monomer ((1) -2) having a functional group.
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 of 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.
Since a glass transition point becomes so low that a monomer with a large carbon number is used as a monomer ((1) -1), the thing of a 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, acrylonitrile for the purpose of improving compatibility and various performances. ) In the range of 5% by weight or less of the total weight.

  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 acrylic And glycidyl methacrylate, allyl glycidyl ether, and those obtained by urethanizing a part of the isocyanate group of a polyisocyanate compound with a monomer having a hydroxyl group or a carboxyl group and a radiation curable carbon-carbon double bond. it can.

Examples of the functional group used in the compound (2) include a hydroxyl group, an epoxy group, and an isocyanate group when the functional group of ((1) -2) is a carboxyl group or a cyclic acid anhydride group. In the case of a hydroxyl group, a cyclic acid anhydride group, an isocyanate group, and the like can be exemplified. In the case of an amino group, an epoxy group, an isocyanate group, and the like can be exemplified. , A carboxyl group, a cyclic acid anhydride group, an amino group, and the like. Specific examples thereof include those similar to those listed in the specific examples of the monomer ((1) -2). .
By leaving an unreacted functional group in the reaction between 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, the molecular weight in this invention is a weight average molecular weight of polystyrene conversion.
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.
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, as a commercial product, Coronate L (trade name, manufactured by Nippon Polyurethane Co., Ltd.) or the like can be used.

Further, as the melamine / formaldehyde resin, specifically, Nicalac MX-45 (trade name, manufactured by Sanwa Chemical Co., Ltd.), Melan (trade name, manufactured by Hitachi Chemical Co., Ltd.), etc. can be used as commercial products. .
Furthermore, as the epoxy resin, TETRAD-X (trade name, manufactured by Mitsubishi Chemical Corporation) or the like can be used.
In the present invention, it is particularly preferable to use polyisocyanates.
The amount of (B) added is preferably 0.1 to 10 parts by weight, more preferably 0.4 to 3 parts by weight, based on 100 parts by weight of the compound (A). If the amount is less than 0.1 parts by weight, the effect of improving the cohesive force tends to be insufficient. If the amount exceeds 10 parts by weight, the curing reaction proceeds rapidly during the formulation and application of the adhesive, and a crosslinked structure is formed. Therefore, workability is 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.

The amount of (C) added is preferably 0.1 to 10 parts by weight and more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the compound (A).
Furthermore, the radiation-curable pressure-sensitive adhesive used in the present invention can be blended with a tackifier, a tackifier, a surfactant, etc., as required, or other modifiers and conventional components. Moreover, you may add an inorganic compound filler suitably.
The thickness of the pressure-sensitive adhesive layer is preferably at least 5 μm, more preferably 10 μm or more when processing is performed in combination with normal wafer dicing. Further, when only laser dicing is performed, it is preferably at least 5 μm or less, more preferably as thin as possible within a range not losing the chip holding power. The pressure-sensitive adhesive layer may have a structure in which a plurality of layers are laminated.

(Adhesive layer)
The dicing die-bonding tape of this invention can be set as the structure by which the adhesive bond layer was further laminated | stacked on the adhesive layer as one aspect | mode.
Here, the adhesive layer means that after a semiconductor wafer or the like is bonded and diced, when the chip is picked up, it is peeled off from the adhesive layer and attached to the chip, and the chip is fixed to the substrate or lead frame. It is used as an adhesive when The adhesive layer is not particularly limited, but may be a film adhesive generally used for dicing die-bonding tapes. Acrylic adhesive, epoxy resin / phenolic resin / acrylic resin blend A system adhesive or the like is preferable. The thickness may be appropriately set, but is preferably about 5 to 100 μm.

  In the dicing die-bonding tape of the present invention, the adhesive layer is formed in advance as an adhesive layer (hereinafter referred to as an adhesive film), and the above-described intermediate resin layer and pressure-sensitive adhesive layer are formed on the base film. You may laminate and form on the adhesive layer surface of the dicing tape of this invention. 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 it is as a cover film for a dicing die bond tape and peeled off when bonding a wafer or the like. Also good. Moreover, although an adhesive film may be laminated | stacked on the whole surface of an adhesive layer, you may laminate | stack the adhesive film cut | disconnected (pre-cut) in the shape according to the wafer bonded beforehand. When the adhesive film according to the wafer is laminated, when using the dicing die-bonding tape of the present invention, the portion where the wafer is bonded has an adhesive layer, and the portion where the dicing ring frame is bonded There is no adhesive layer and it is used by being bonded to the pressure-sensitive 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 pressure-sensitive adhesive layer composition and the adhesive are adjusted as follows, and the pressure-sensitive adhesive layer compositions 2A to 2B are applied to the base film 1A to 1E so that the dry film thickness is 10 μm or 5 μm, and 110 ° C. Was dried for 3 minutes to prepare a dicing tape. Adhesive films 3A to 3C are bonded onto the pressure-sensitive adhesive layer of these pressure-sensitive adhesive tapes, and the dicing die-bonding tapes of Examples 1 to 6 and Comparative Examples 1 to 3 as shown in Table 1 and Table 2 are produced, and the characteristics are evaluated. I did it.

The resin and treatment used for the base film are shown below.
Base film 1A: Polypropylene (FW3E manufactured by Nippon Polychem) was formed into a film without being subjected to graining.
Base film 1B: ethylene-vinyl acetate copolymer Film formation was carried out without subjecting a 5% by mass vinyl acrylate content to a texture.
Substrate film 1C: An ethylene-ionomer copolymer (Mitsui DuPont Chemical's HiMilan 1706) was formed into a film without being textured.
Base film 1D: Polypropylene (FW3E manufactured by Nippon Polychem Corp.) was subjected to texturing to form a film.
Base film 1E: Polyethylene terephthalate (PET) was formed into a film without being textured.

Preparation of pressure-sensitive adhesive layer composition (pressure-sensitive 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 the 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 weight of the compound (A) in the compound (A) solution is made by Nippon Polyurethane Co., Ltd. as a polyisocyanate (B): 1 part by weight 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 weight of Irgacure 184 and 150 parts by weight of ethyl acetate as a solvent to the compound (A) solution and mixing them.

(Adhesive composition 2B)
Adhesive by mixing 100 parts by weight of acrylic resin (weight average molecular weight: 600,000, glass transition temperature -20 ° C.) and 5 parts by weight of a polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate L) as a curing agent. Composition 2B was obtained.

Production of adhesive film (adhesive film 3A)
50 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) as an epoxy resin, 1.5 parts by weight of γ-mercaptopropyltrimethoxysilane as a silane coupling agent, γ-ureidopropyltriethoxysilane Cyclohexanone was added to a composition comprising 3 parts by weight of silica filler having an average particle diameter of 16 nm and 30 parts by weight, and the mixture was stirred and mixed, and further kneaded for 90 minutes using a bead mill.
100 parts by weight of acrylic resin (weight 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 Cureazole 2PZ (trade name, 2-phenylimidazole, manufactured by Shikoku Chemicals 1 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 20 μm, and an adhesive with a carrier film Film 3A was produced.

(Adhesive 3B)
Exactly the same operation as the production of the adhesive film 3A except that 50 parts by weight of a cresol novolac type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) was used as the epoxy resin, and 1 part of hexamethylene diisocyanate adduct was used as the curing agent. The adhesive film 3B was produced.

(Adhesive 3C)
As a curing agent, 0.5 part of an adduct of hexamethylene diisocyanate is used, and instead of Curezol 2PZ, Curezole 2PHZ (trade name, 2-phenyl-4,5-dihydroxyimidazole, manufactured by Shikoku Kasei Co., Ltd.) Except for the above, the same operation as in the production of the adhesive film 3A was performed to produce an adhesive film 3C.

(Characteristic evaluation)
About the dicing die-bonding tapes of Examples 1 to 6 and Comparative Examples 1 to 3 as shown in Table 1 and Table 2, parallel light transmittance, total light transmittance, substrate film back surface roughness Ra, adhesive layer laser processing The characteristics of the property and the pickup success rate were evaluated as follows.

(Parallel light transmittance, total light transmittance)
About the part which does not contain the adhesive which laminated | stacked the base film and the adhesive layer of the dicing die-bonding tape obtained by an Example and a comparative example, the total light transmittance in wavelength 355nm from a base film back side, parallel light transmission The rate was measured at N = 5 using a transmittance meter (trade name: UV3101PC & MPC-3100, manufactured by Shimadzu Corporation), and the average value was obtained. This device has an integrating sphere type light receiving unit and is capable of measuring the total light transmittance, but the parallel light transmittance was also measured by pulling the sample fixed position 70 mm away from the integrating sphere entrance window. .

(Surface roughness Ra)
The dicing die-bonding tapes obtained by Examples and Comparative Examples are fixed by being bonded to a smooth mirror wafer, and the arithmetic surface roughness Ra on the back side of the base film is measured by a surface roughness measuring instrument (trade name: Surf, manufactured by Mitutoyo Corporation). Using test SJ-301), the average value was obtained by measuring N = 5 in the film extrusion direction (MD direction).

(Adhesive layer laser processability)
In the dicing die-bonding tape obtained by the example and the comparative example, a notch groove of 10 mm × 10 mm shallower than the wafer thickness is formed in the street portion between the chips of the semiconductor wafer, and the surface protection tape is attached to the surface of the semiconductor wafer. The silicon wafer with the surface protective tape, which was ground to 80 μm in thickness until the street part was completely opened and was divided into chips, was heat bonded at 70 ° C. for 10 seconds, and then laser dicing apparatus ( Laser dicing was performed along the street portion between the chips using a disco product (trade name: DFL7160). Thereafter, the pressure-sensitive adhesive layer was irradiated with ultraviolet rays of 200 mJ / cm ² by an air-cooled high-pressure mercury lamp (80 W / cm, irradiation distance 10 cm), and the dicing tape portion was peeled off from the adhesive layer. Observations were made. The judgment at that time is as follows.

○ ・ ・ ・ When the adhesive layer is cut without being connected at the street part between the chip and the chip. × ・ ・ ・ The adhesive layer is connected and cut at the street part between the chip and the chip. If not

(Pickup success rate)
In the dicing die-bonding tape described in the examples and comparative examples, a notch groove having a depth of 10 mm × 10 mm shallower than the wafer thickness is formed in the street portion between the chips of the semiconductor wafer, and a surface protection tape is attached to the surface of the semiconductor wafer. A silicon wafer with a surface protection tape, which was ground to a thickness of 80 μm and divided into chips, was heated and bonded at 70 ° C. for 10 seconds until the street portion was completely opened, and then laser dicing equipment (disco Laser dicing was performed along the street portion between the chips using a product name, DFL7160). Thereafter, the adhesive layer was irradiated with ultraviolet rays of 200 mJ / cm ² with 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.
(Pickup success rate (2))
In the dicing die bond tape described in the examples and comparative examples, a notch groove of 15 mm × 15 mm shallower than the wafer thickness is formed in the street portion between the chips of the semiconductor wafer, and a surface protection tape is attached to the surface of the semiconductor wafer. A silicon wafer with a surface protection tape, which was ground to a thickness of 80 μm and divided into chips, was heated and bonded at 70 ° C. for 10 seconds until the street portion was completely opened, and then laser dicing equipment (disco Laser dicing was performed along the street portion between the chips using a product name, DFL7160). Thereafter, the adhesive layer was irradiated with ultraviolet rays of 200 mJ / cm ² with 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.
Tables 1 and 2 summarize the parallel light transmittance, total light transmittance, base film back surface roughness Ra, adhesive layer laser processability, and pickup success rate in each example and comparative example.

In the case of using the tape of Comparative Example 1 in which the base film is subjected to graining and the Comparative Example 2 in which the PET film base mainly composed of an aromatic resin is used, the adhesive layer processability is poor at the time of laser dicing. The connection between the chip and the chip occurred, and the pick-up failure occurred frequently. In Comparative Example 3 in which a pressure-sensitive adhesive layer having no radiation curability was used as the pressure-sensitive adhesive layer, the laser dicing processability was good, but pickup was impossible.
After directly mounting an IC chip having a size of 10 mm × 10 mm obtained by laser dicing a silicon wafer using the dicing die bond tape of Examples 1 to 5 on a lead frame using a die bonder, 170 ° C., It was confirmed that the lead frame and the IC chip were firmly bonded by heating under conditions of 2 hours.

It is sectional drawing showing the state which put the cutting groove in the site | part equivalent to the penetration part of a wafer. It is sectional drawing which bonded the protective adhesive tape on the wafer surface, (A) is a state before a penetration part opens, (B) represents the state which grind | polished the wafer back surface and was divided into pieces. It is sectional drawing showing the state which bonded the die-bonding sheet | seat on the grinding | polishing surface of the wafer. It is sectional drawing showing the state which bonded and fixed with the ring frame the dicing die-bonding tape on the surface where the die-bonding sheet was bonded. It is sectional drawing which irradiates a laser along the penetration part opened from the base-material film side of the dicing die-bonding tape, (A) represents during irradiation, (B) represents the state which divided | segmented and separated the die-bonding film. It is sectional drawing showing the state after protection adhesive tape peeling from the state of FIG. It is sectional drawing showing the state by which the chip | tip with a die-bonding film peels from a dicing die-bonding tape adhesive layer, and is extract | collected. It is sectional drawing which shows the example of a general blade cut dicing system. It is sectional drawing which shows the state in which the chip | tip was joined to the lead frame with the liquid adhesive agent. It is sectional drawing which shows the dicing in the state by which the dicing tape was bonded by the wafer back surface. Sectional view when cutting a die-bonding sheet between chips with a dicing blade having the same thickness as the chip-chip width. (A) is before cutting, (B) is a state where the blade is in contact with the side of the chip. To express. It is sectional drawing when the die-bonding sheet | seat between chips | tips is cut | disconnected with a dicing blade thinner than the width | variety between a chip | tip, (A) is before cutting | disconnection and (B) represents the state cut | disconnected. FIG. 13 is a cross-sectional view illustrating a state in which the die bond sheet is cut by a size larger than a chip size as a result of cutting the die bond sheet by the method of FIG. 12.

Explanation of symbols

1 semiconductor wafer 1 'separated semiconductor chip 2 blade 3 ring frame
4 Dicing Tape Adhesive Layer 5 Dicing Tape Base Film 6 Dicing Tape 7 Dicer Chuck Table 8 Liquid Adhesive 9 Inner Lead 10 Die Pad 11 Lead Frame 12 Die Bond Film (Adhesive Layer)
12 'Divided die bond film 13 Cut groove 14 Adhesive layer of surface protection tape 15 Base film of surface protection tape 16 Surface protection tape 17 Base film of dicing die bond tape 18 Dicing die bond tape 19 Laser

Claims (6)

In a dicing die-bonding tape in which an adhesive layer is directly or indirectly formed on a base film, the total light transmittance at 355 nm when the adhesive layer is peeled off and irradiated with light from the base film is 70%. The parallel light transmittance is 30% or more, and the surface roughness Ra of the base film opposite to the surface on which the adhesive layer is provided is 0.5 μm or less. Dicing die bond tape. The dicing die-bonding tape according to claim 1, wherein the base film is a polyolefin film. The dicing die-bonding tape according to claim 1 or 2, wherein a pressure-sensitive adhesive layer is provided on a layer in contact with the base film layer among the adhesive layers, and the adhesive layer is laminated directly or indirectly on the pressure-sensitive adhesive layer. . The pressure-sensitive adhesive layer is a compound (A) having a radiation curable carbon-carbon double bond having an iodine value of 0.5 to 20 in the molecule, at least selected from polyisocyanates, melamine / formaldehyde resins and epoxy resins. 4. The dicing die-bonding tape according to claim 3, comprising a polymer obtained by addition reaction of one kind of compound (B). A dicing die-bonding tape that is fixed to a dicing frame during dicing, fixed in a wafer, diced, and used in an adhesion process for stacking with a lead frame or semiconductor chip. The dicing die-bonding tape according to claim 3 or 4, wherein an adhesive layer is not provided in a portion bonded to the frame. The dicing die-bonding tape according to any one of claims 3 to 5, wherein the adhesive layer has a pressure-sensitive adhesive layer having a thickness of 5 µm or less.

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