JP2009164556A - Tape for processing wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expandable adhesive tape for improving cutting property of an adhesive tape, due to expanding, under a low temperature within a range of -15 to 5°C. <P>SOLUTION: A tape for processing wafer includes an adhesive tape 10 having a base material sheet 11 and an adhesive layer 12. The tape is also provided with an adhesive film 13 arranged on the adhesive layer 12. The tape is used for cutting the adhesive film 13 corresponding to each chip by expanding the adhesive tape 10, under a low temperature within a range of -15 to 5°C. Peeling force of the adhesive tape 10 from the adhesive film 13 obtained in peeling test at 0±2°C is 0.2 N/25 mm or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wafer processing tape in which a pressure-sensitive adhesive tape and an adhesive film are laminated, and more particularly to a wafer processing tape that is used when an adhesive film is divided into individual chips by expanding.

  In the manufacturing process of a semiconductor device, after attaching a stretchable and adhesive wafer processing tape to a semiconductor wafer, the semiconductor wafer is cut (diced) into chips, the adhesive tape is expanded, and further cut. A step of picking up the chip is performed.

  As a wafer processing tape used in the manufacturing process of the semiconductor device, in addition to an adhesive tape (dicing tape) composed of a base sheet and an adhesive layer, a die bonding film (die attach film) which is a dicing tape and an adhesive film A dicing die-bonding film having a structure in which is also laminated is proposed.

  Generally, when using a dicing die bonding film, first, the die bonding film side of the dicing die bonding film is bonded to the back surface of the semiconductor wafer to fix the semiconductor wafer, and then the semiconductor wafer and the die bonding film are used using a dicing blade. Is diced into chips. Thereafter, the dicing tape is expanded in the circumferential direction to widen the distance between the chips. This expanding process is performed to improve chip recognition by a CCD camera or the like, and to prevent damage to the chips caused by contact between adjacent chips when picking up the chips.

  However, in the dicing process, when the semiconductor wafer and the die bonding film are diced together using a dicing blade, not only the wafer cutting waste but also the die bonding film cutting waste is generated. Since the cutting dust of the die bonding film itself has an adhesive function, when the cutting dust is clogged in the dicing groove of the wafer, the chips stick to each other to cause a pick-up failure and the like, and the manufacturing yield of the semiconductor device decreases.

  In order to solve the above problems, there has been proposed a method in which only the semiconductor wafer is diced in the dicing process, and the dicing tape is expanded in the expanding process to divide the die bonding film corresponding to each chip. (For example, paragraph number “0055” to paragraph number “0056” of Patent Document 1). According to such a method for dividing the die bonding film using the tension at the time of expansion, no cutting waste of the adhesive is generated, and there is no adverse effect in the pickup process.

  As a method for cutting a semiconductor wafer, a half-cut dicing method is known in which a groove having a cutting depth shallower than the thickness of the wafer is formed from the wafer surface without performing full-cut dicing of the semiconductor wafer. In this method, the wafer can be divided into chips by expanding a dicing tape that holds the half-cut wafer. And also in this half-cut dicing method, it is possible to divide a die-bonding film with a wafer using the tension | tensile_strength at the time of an expansion.

  In recent years, a so-called stealth dicing method in which a wafer is cut in a non-contact manner using a laser processing apparatus has been proposed as a method for cutting a semiconductor wafer.

  For example, in Patent Document 2, as a stealth dicing method, laser light is applied by focusing light on the inside of a semiconductor substrate on which a sheet (dicing tape) is attached with a die bonding resin layer (die bonding film) interposed therebetween. By forming a modified region by multiphoton absorption inside the semiconductor substrate and forming the planned cutting portion in this modified region, the semiconductor is expanded along the planned cutting portion by expanding (expanding) the sheet. A method for cutting a semiconductor substrate comprising a step of cutting a substrate and a die bond resin layer is disclosed.

According to the semiconductor substrate cutting method of Patent Document 2, since the semiconductor wafer and the die bond resin layer (die bonding film) are cut in a non-contact manner by laser light irradiation and sheet expansion, as in the case of using a dicing blade. The semiconductor wafer can be cut without causing chipping. Therefore, it is particularly useful when, for example, an ultrathin semiconductor wafer of 50 μm or less is cut.
JP 2007-5530 A JP 2003-338467 A

  As described above, in order to avoid the generation of cutting scraps of the die bonding film as an adhesive even when any of the full cut dicing method, the half cut dicing method, and the stealth dicing method is employed, It is effective to divide the die bonding film by expanding.

  However, since the die bonding film is flexible and easily stretched, there is a problem that the die bonding film is difficult to be divided by the expansion of the dicing tape. In order to improve the ability to expand the die bonding film by expanding, it is conceivable to change the composition and properties of the die bonding film itself, but the original function of the die bonding film, that is, bonding to the backside of the semiconductor chip Thus, the function as an adhesive such as mounting a semiconductor chip on a package substrate or the like may be hindered, and it is not preferable to change the composition and characteristics of the die bonding film itself. For these reasons, it is desired to develop a dicing tape that can improve the splitting property of the die bonding film.

  Then, the objective of this invention is providing the tape for wafer processing which can improve the parting property of the adhesive film by an expand under the low temperature of -15 degreeC-5 degreeC.

As a result of intensive studies on the above problems, the present inventors have obtained the following findings.
(1) The adhesive film (die bonding film) can be hardened and easily separated by carrying out the expanding step at a low temperature of about -15 ° C to 5 ° C.

(2) Under the low temperature as described above, if the adhesive strength of the adhesive tape holding the adhesive film is insufficient, peeling occurs between the adhesive film and the adhesive tape during expansion, and as a result, only the adhesive tape Therefore, the adhesive tape must be strong enough to hold the adhesive film even at a low temperature as described above.

(3) By using a pressure-sensitive adhesive tape having a peel strength (according to JIS Z 0237) of 0.2 N / 25 mm or more for an adhesive film obtained by a peel test at 0 ° C. ± 2 ° C., the above low temperature The adhesive strength with respect to the adhesive film can be sufficiently secured even underneath, and peeling between the adhesive film and the adhesive tape can be suppressed to improve the splitting property of the adhesive film.
The present invention has been completed based on the above findings.

  That is, the first aspect of the present invention is a wafer processing tape comprising an adhesive tape having a base sheet and an adhesive layer, and an adhesive film provided on the adhesive layer of the adhesive tape. The adhesive film is used to divide the adhesive film in correspondence with individual chips by expanding the adhesive tape at a low temperature of -15 ° C to 5 ° C. The tape is characterized in that the peel force for the adhesive film obtained by a peel test at 2 ° C. is 0.2 N / 25 mm or more.

  According to a second aspect of the present invention, in the wafer processing tape according to the first aspect, the base sheet of the adhesive tape has an elongation of 200% or more and a Young's modulus of 200 MPa or more at 0 ° C. ± 2 ° C. It is characterized by that.

  3rd aspect of this invention has a base material sheet and the adhesive layer provided in the single side | surface of this base material sheet, and each adhesive film by an expand under low temperature of -15 degreeC-5 degreeC Expandable pressure-sensitive adhesive tape that is used for cutting in accordance with the chip of the above, and has a peel strength of 0.2 N / 25 mm or more with respect to the adhesive film obtained by a peel test at 0 ° C. ± 2 ° C. It is an adhesive tape characterized by.

  The wafer processing tape of the present invention is excellent in the adhesive strength of the adhesive tape to the adhesive film, and can suppress peeling between the adhesive film and the adhesive tape even when expanded at a low temperature. Therefore, by performing the expansion at a low temperature, it is possible to propagate the tension due to the expansion of the adhesive tape to the adhesive film while maintaining the high breakability of the adhesive film. Correspondingly, it can be divided well.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a cross-sectional view of a wafer processing tape showing an embodiment of the present invention. The wafer processing tape includes a pressure-sensitive adhesive tape 10 having a base sheet 11 and a pressure-sensitive adhesive layer 12, and an adhesive film 13 provided on the pressure-sensitive adhesive layer 12.

  The wafer processing tape of the present invention is used when the adhesive film 13 is divided corresponding to individual chips by expanding the adhesive tape 10 at a low temperature of −15 ° C. to 5 ° C. 10 peel strength (according to JIS Z 0237) to the adhesive film 13 obtained by a peel test at 0 ° C. ± 2 ° C. is 0.2 N / 25 mm or more. If the peel strength of the adhesive tape 10 to the adhesive film 13 is small, the adhesive strength to the adhesive film 13 is insufficient, and peeling occurs between the adhesive film 13 and the adhesive tape 10 during expansion at a low temperature. The adhesive film 13 cannot be divided. If the peeling force with respect to the adhesive film 13 is 0.2 N / 25 mm or more, sufficient adhesive strength with respect to the adhesive film 13 can be ensured even at low temperatures, and the adhesive film 13 and the adhesive tape 10 can be secured. The peeling property of the adhesive film 13 can be improved.

In this invention, the peeling force with respect to the adhesive film 13 of the adhesive tape 10 is obtained by the following peeling tests according to JISZ0237 using the tension test apparatus according to JISB7721.
Peel strength (adhesive strength): A test piece having a width of 25 mm and a length of about 100 mm in which the adhesive film 13 and the adhesive tape 10 are laminated is prepared, and a 2 kg rubber roller is reciprocated on a silicon wafer by three reciprocations and thermocompression bonded. After being left for 1 hour, the peeling force (adhesive strength) of the adhesive tape 10 to the adhesive film 13 is measured at 0 ° C. ± 2 ° C. using the tensile test apparatus. The measurement is performed by a 90 ° peeling method at a tensile speed of 50 mm / min.

  Below, a base sheet, an adhesive layer, and an adhesive film are each demonstrated in detail.

<Base material sheet>
The base material sheet 11 has an elongation of 200% or more and a Young's modulus of 200 MPa or more at 0 ° C. ± 2 ° C. If the elongation is less than 200%, the expandability is poor and the splitting properties of the wafer and the adhesive film are lowered. If the Young's modulus is low, the substrate sheet becomes too soft and the uniformity of the expansion of the adhesive tape deteriorates.

In the present invention, the elongation percentage of the base sheet is obtained by the following tensile test using a tensile test apparatus (JIS B 7721).
Elongation rate: A base sheet is punched out in a No. 1 dumbbell shape (JIS K 6301) to prepare a test piece, and an elongation rate at the time of fracture between marked lines at a distance between marked lines of 40 mm and a tensile speed of 300 mm / min is measured.
Moreover, in this invention, the Young's modulus of a base material sheet says the inclination of the linear part of the stress-elongation rate curve obtained by the said tension test.

  The material constituting the base sheet is not particularly limited as long as it has the above characteristics, but is preferably selected from polyolefin and polyvinyl chloride.

  Examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid. Examples thereof include homopolymers or copolymers of α-olefins such as methyl copolymers, ethylene-acrylic acid copolymers, and ionomers, or mixtures thereof.

  In the case where a type that is cured by irradiation with radiation and has a reduced adhesive strength is used as the pressure-sensitive adhesive layer to be described later, the substrate sheet preferably has the above properties and is radiation transmissive. The thickness of the base sheet is preferably 50 to 300 μm from the viewpoint of securing strength and chip pickup performance. Moreover, the base sheet may be a single layer or may be composed of a plurality of layers.

<Adhesive layer>
The pressure-sensitive adhesive layer 12 can be produced by applying a pressure-sensitive adhesive on the base sheet 11. Although there is no restriction | limiting in particular as the adhesive layer 12, The peeling force (adhesion strength) with respect to the adhesive film bonded on the adhesive layer 12 satisfy | fills said range, and peeling with an adhesive film at the time of pick-up is carried out. Any material having an easy characteristic may be used. In order to improve the pick-up property, the pressure-sensitive adhesive layer 12 is preferably radiation curable.

  For example, in the present invention, the main chain is an acrylic copolymer having at least a radiation-curable carbon-carbon double bond-containing group, a hydroxyl group, and a group containing a carboxyl group, and the gel fraction. Is preferably 60% or more. Furthermore, 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. It is preferable to contain a polymer obtained by addition reaction of the compound (B).

  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. 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. When the glass transition point (hereinafter referred to as Tg) is −70 ° C. or higher, the heat resistance against heat associated with radiation irradiation is sufficient, and when the glass transition point is 0 ° C. or lower, the element after dicing on the 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 the radiation curable carbon-carbon double bond and the 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 ((1) -2) having a functional group. About the amount of adhesive double bonds, the amount of carbon-carbon double bonds contained in about 10 g of the heat-dried adhesive can be quantitatively measured by a weight increase method by bromine addition reaction in a dark place in vacuum.

  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 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 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.

  In the compound (2), as the functional group used, when the functional group of the compound (1), that is, the monomer ((1) -2) is a carboxyl group or a cyclic acid anhydride group, a hydroxyl group, Examples include an epoxy group and an isocyanate group. In the case of a hydroxyl group, examples include a cyclic acid anhydride group and an isocyanate group. In the case of an amino group, examples include an epoxy group and 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 mentioned. Specific examples include those listed in the specific examples of the monomer ((1) -2) Can be listed.

  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, preferably having a boiling point of 60 to 120 ° C., and α, α′-azobisisobutyl as a polymerization initiator 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 weight average 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 weight average molecular weight is preferably 400,000 or more. Moreover, when a weight average molecular weight exceeds 1 million, there exists a possibility of gelatinizing at the time of a synthesis | combination and a coating.
In addition, the weight average 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 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 cohesive force of the pressure-sensitive adhesive mainly composed of the compounds (A) and (B) is obtained by the cross-linking structure formed as a result of reaction with the compound (A) or the base sheet. 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 (manufactured by Nippon Polyurethane Co., Ltd., trade name) or the like can be used.

Specific examples of the melamine / formaldehyde resin include Nicalac MX-45 (trade name, manufactured by Sanwa Chemical Co., Ltd.), Melan (trade name, manufactured by Hitachi Chemical Co., Ltd.), and the like.
Furthermore, as an epoxy resin, TETRAD-X (Mitsubishi Chemical Corporation make, brand name) etc. can be used.
In the present invention, it is particularly preferable to use polyisocyanates.

  The addition amount of (B) needs to be selected so as to be a ratio of 0.1 to 10 parts by mass, preferably 0.4 to 3 parts by mass with respect to 100 parts by mass of the compound (A). By selecting within this range, it is possible to obtain an appropriate cohesive force, and since the crosslinking reaction does not proceed abruptly, workability such as blending and application of the adhesive is improved.

In the present invention, the pressure-sensitive adhesive layer 12 preferably contains a photopolymerization initiator (C). There is no restriction | limiting in particular in the photoinitiator (C) in which the adhesive layer 12b 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.

  The thickness of the pressure-sensitive adhesive layer is preferably at least 5 μm, more preferably 10 μm or more. The pressure-sensitive adhesive layer may have a structure in which a plurality of layers are laminated.

<Adhesive film>
When the chip is picked up after the semiconductor wafer is bonded and cut, the adhesive film 13 is peeled off from the adhesive layer 12 and attached to the chip when the chip is picked up. It functions as a bonding film for fixing to a lead frame.

  Although it does not specifically limit as the adhesive film 13, Although the film adhesive generally used as a die bonding film can be used conveniently, a polyimide-type adhesive agent and an acrylic adhesive agent Epoxy resin / phenolic resin / acrylic resin / inorganic filler blend adhesives are preferred. The thickness may be appropriately set, but is preferably about 5 to 100 μm.

<Application>
The usage of the wafer processing tape of the present invention is not particularly limited as long as it is at least an adhesive film dividing application. For example, on the wafer on which the part that becomes the starting point of cutting by the half-cut dicing method and stealth dicing method is formed on the back surface of the adhesive film pasted on the back surface of the wafer diced by the full-cut dicing method It can be used for a parting application with the adhered adhesive film.

<How to use>
A method for using the wafer processing tape of the present invention when the stealth dicing method is used will be described with reference to FIGS.
First, as shown in FIG. 2, a laser beam is irradiated on a part to be divided of the semiconductor wafer W to form a modified region 30 by multiphoton absorption inside the wafer. Separately, an adhesive film 13 is bonded onto the pressure-sensitive adhesive layer 12 of the pressure-sensitive adhesive tape 10 including the base material sheet 11 and the pressure-sensitive adhesive layer 12 shown in FIG. 2, and the wafer processing tape shown in FIG. 1 is prepared.

Next, as shown in FIG. 4A, the back surface of the semiconductor wafer W is attached to the adhesive film 13, the ring frame 20 is attached to the outer peripheral portion of the adhesive layer 12, and the base sheet 11 of the adhesive tape. Is placed on the stage 21 of the expanding apparatus. In the figure, reference numeral 22 denotes a hollow cylindrical push-up member of the expanding device.
Prior to the step of irradiating the semiconductor wafer W with laser light, a bonding step with the adhesive film 13 may be performed.

Next, at a low temperature of −15 ° C. to 5 ° C., as shown in FIG. 4B, with the ring frame 20 fixed, the push-up member 22 of the expanding device is raised to expand the adhesive tape 10. . As a result, the adhesive tape 10 is stretched in the circumferential direction, and the semiconductor wafer W is divided in units of chips starting from the modified region, and the adhesive layer 13 is also divided.
Thereafter, the adhesive layer 12 is subjected to radiation curing treatment or thermosetting treatment and the semiconductor chip C is picked up, whereby a semiconductor chip with an adhesive can be obtained.

  In the expanding process as described above, the adhesive film 13 is prevented from expanding (deformation) due to the expansion at the portion bonded to the back surface of the wafer W, and does not break. The tension due to the expansion of the tape 10 concentrates and breaks. According to the present invention, by using an adhesive tape excellent in peeling force (adhesive strength) for an adhesive film, peeling between the adhesive tape and the adhesive film can be achieved even in an expanding process at a low temperature. It can be suppressed and prevented. Therefore, the tension at the time of expansion can be propagated to the adhesive film while keeping the adhesive film in a high state at low temperatures, and the adhesive film can be divided well in correspondence with individual chips. it can. Moreover, since the adhesive tape 10 is excellent also in the adhesive strength with respect to the ring frame of an expanding apparatus, it can also prevent peeling from a ring frame.

  Next, examples of the present invention will be described, but the present invention is not limited to these examples.

The used base sheet, pressure-sensitive adhesive layer composition, and adhesive composition are shown below.
Substrate sheet A: ionomer resin sheet substrate sheet B: ionomer resin sheet substrate sheet C: ethylene-vinyl acetate copolymer resin sheet pressure-sensitive adhesive layer composition a: acrylic radiation-curable pressure-sensitive adhesive composition pressure-sensitive adhesive layer composition Product b: Acrylic radiation curable pressure sensitive adhesive composition pressure sensitive adhesive layer composition c: Acrylic radiation curable pressure sensitive adhesive composition adhesive composition (1): Epoxy-acrylic adhesive adhesive composition (2): Epoxy-acrylic adhesive composition (3): Epoxy-acrylic adhesive

Example 1
A pressure-sensitive adhesive layer composition a dissolved in an organic solvent was applied to the base sheet A so that the dry film thickness was 10 μm, and dried at 110 ° C. for 3 minutes to prepare a pressure-sensitive adhesive tape. Separately, an adhesive layer composition (1) dissolved in an organic solvent is applied onto a release-treated polyethylene terephthalate (PET) film, dried by heating at 110 ° C. for 1 minute, and an adhesive film in a B-stage state ( Adhesive layer) was obtained. The adhesive tape and the adhesive film with a PET film were cut into circles having a diameter of 370 mm and 320 mm, respectively, and the adhesive layer and the adhesive layer of the adhesive tape were bonded together. Finally, the PET film was peeled from the adhesive layer, and the wafer processing tape of Example 1 was obtained.

(Example 2)
A wafer processing tape of Example 2 was produced in the same manner as in Example 1 except that the adhesive composition (2) was used as the adhesive composition.

(Example 3)
A wafer processing tape of Example 3 was produced in the same manner as in Example 1 except that the adhesive composition (3) was used as the adhesive composition.

Example 4
Implemented in the same manner as in Example 1 except that the substrate sheet C was used as the substrate sheet, the adhesive composition c was used as the adhesive composition, and the adhesive composition (2) was used as the adhesive composition. The wafer processing tape of Example 4 was produced.

(Comparative Example 1)
A wafer processing tape of Comparative Example 1 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition b was used as the pressure-sensitive adhesive and the base material sheet B was used as the base material sheet.

<Peeling force test>
Using a tensile tester conforming to JIS B 7721, the following peel test was performed according to JIS Z 0237.
Peeling strength (adhesive strength): A test piece having a width of 25 mm and a length of about 100 mm in which an adhesive film and an adhesive tape were laminated was prepared, and a 2 kg rubber roller was reciprocated on a silicon wafer by three reciprocations and thermocompression bonded. After leaving for 1 hour, the peeling force (adhesion strength) of the adhesive tape to the adhesive film was measured at 0 ° C. ± 2 ° C. using the tensile test apparatus. The measurement was performed by a 90 ° peeling method at a tensile speed of 50 mm / min.

<Elongation rate and Young's modulus of base sheet>
Using a tensile test apparatus (JIS B 7721), the elongation percentage of the base sheet was measured by the following tensile test in an environment of 0 ° C. ± 2 ° C.
Elongation rate: A base sheet was punched out in a No. 1 dumbbell shape (JIS K 6301) to prepare a test piece, and the elongation rate at the time of fracture between marked lines at a distance between marked lines of 40 mm and a tensile speed of 300 mm / min was measured.
The Young's modulus was calculated from the slope of the straight line portion of the stress-elongation curve obtained by this tensile test.

<Partitionability test of adhesive layer>
A semiconductor wafer (thickness 50 μm, diameter 300 mm) was irradiated with a laser beam to form a modified region inside the wafer. The wafer processing tapes of Examples 1, 2, 3 and Comparative Example 1 were laminated on the semiconductor wafer after laser irradiation and the stainless steel ring frame. Next, a resin expanded ring having an inner diameter of 330 mm was attached to the outer peripheral portion of the adhesive tape, the ring was fixed by an expanding device, and the adhesive tape was expanded under the following expanding conditions.
Expanding speed: 100mm / sec
Expanding amount: 15mm
Then, the adhesive tape was irradiated with ultraviolet rays, the adhesive layer of the adhesive tape was cured, and the adhesive strength was reduced.

<Method for evaluating the splitting property of the adhesive layer>
After the expansion, it was observed with an optical microscope whether or not the adhesive layer was divided together with the semiconductor wafer. The results are shown in Table 1. The severability shown in Table 1 is a percentage of the number of adhesive layers that were successfully severed with respect to the total number of chips. The total number of chips after laser processing is about 400, and the chip size is 10 mm × 10 mm.

  From the results in Table 1, it can be seen that the wafer processing tapes of Examples 1 to 4 in which the peel strength of the pressure-sensitive adhesive tape with respect to the adhesive film is 0.2 N / 25 mm or more show excellent severability, and the effect of the present invention. I was able to confirm.

It is sectional drawing which shows an example of the tape for wafer processing of this invention. It is sectional drawing which shows the adhesive tape of this invention. It is sectional drawing which shows a mode that the modification | reformation area | region was formed in the semiconductor wafer by laser processing. (A) is sectional drawing which shows the state in which the tape for wafer processing was mounted in the expand apparatus, (b) is sectional drawing which shows the tape for wafer processing after expansion, and a semiconductor wafer.

Explanation of symbols

10: Adhesive tape 11: Base sheet 12: Adhesive layer 13: Adhesive film 20: Ring frame 21: Stage 22: Push-up member

Claims (3)

An adhesive tape having a base sheet and an adhesive layer;
A wafer processing tape comprising an adhesive film provided on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape,
Used at the low temperature of −15 ° C. to 5 ° C. to divide the adhesive film corresponding to individual chips by expanding the adhesive tape,
A wafer processing tape, wherein the pressure-sensitive adhesive tape has a peel strength of 0.2 N / 25 mm or more with respect to an adhesive film obtained by a peel test at 0 ° C. ± 2 ° C.   2. The wafer processing tape according to claim 1, wherein the substrate sheet of the adhesive tape has an elongation of 200% or more and a Young's modulus of 200 MPa or more at 0 ° C. ± 2 ° C. 3. When having a base sheet and a pressure-sensitive adhesive layer provided on one side of the base sheet, and dividing the adhesive film corresponding to individual chips by expanding at a low temperature of −15 ° C. to 5 ° C. Expandable adhesive tape used for
A pressure-sensitive adhesive tape characterized by having a peel strength of 0.2 N / 25 mm or more for an adhesive film obtained by a peel test at 0 ° C. ± 2 ° C.

Images