TWI605502B - Semiconductor wafer surface protection adhesive tape and semiconductor wafer processing method - Google Patents

Description

Adhesive tape for semiconductor wafer surface protection and method for processing semiconductor wafer

The present invention relates to a method for processing a semiconductor wafer surface protective adhesive tape and a semiconductor wafer. More specifically, the present invention relates to a semiconductor wafer surface protective adhesive tape which can be applied to a semiconductor wafer thin film grinding step, and a semiconductor wafer processing method using the semiconductor wafer surface protective adhesive tape.

In the manufacturing process of the semiconductor wafer, the semiconductor wafer after the pattern formation is usually subjected to back grinding, etching, or the like on the back surface of the semiconductor wafer in order to reduce the thickness thereof. At this time, the semiconductor wafer surface protective adhesive tape is attached to the pattern surface for the purpose of protecting the pattern of the surface of the semiconductor wafer. The adhesive tape for surface protection of a semiconductor wafer is generally formed by laminating an adhesive layer of a base resin film, and is adhered to an adhesive layer on the back surface of the semiconductor wafer.

With the advancement of high-density mounting technology in recent years, there is a demand for thinning of semiconductor wafers, and thinning processing up to a thickness of 50 μm or less is required depending on the situation. As one of the processing methods The post-cut polishing method is to form a groove having a specific depth on the surface of the semiconductor wafer before the back surface of the semiconductor wafer is ground, and then performing back-side grinding to reduce the wafer (for example, refer to Patent Document 1). Further, there is also a method of invisible dicing polishing which forms a modified field by irradiating a laser inside a semiconductor wafer before the back grinding process, and then performing back grinding, thereby miniaturizing the wafer (for example, refer to the patent) Literature 2).

However, in the post-cutting polishing method and the invisible post-cutting polishing method, in order to suppress wafer shift (cutting offset) after dicing, it is required that the adhesive tape for surface protection of the semiconductor wafer used has a high modulus of elasticity. However, since the elastic modulus of the adhesive tape for semiconductor wafer surface protection is increased, it is difficult to bend, and thus the peeling angle when the semiconductor wafer surface protective adhesive tape is peeled off from the surface of the semiconductor wafer becomes an acute angle. The semiconductor wafer is damaged, or the surface of the semiconductor wafer is likely to cause contamination of the semiconductor wafer such as adhesive residue adhering to the adhesive residue of the adhesive tape for the semiconductor wafer surface.

Further, in the post-cutting polishing method or the invisible-cutting polishing method, since the wafer is diced during the grinding process, if the peeling property of the semiconductor wafer surface protecting adhesive tape is poor, the wafer is generated at the time of peeling. The dicing tape attached to the back surface of the semiconductor wafer or the phenomenon in which the dicing die film is torn off (hereinafter referred to as wafer delamination).

Therefore, for the adhesive tape for semiconductor wafer surface protection which is suitable for the post-cutting polishing method and the invisible post-cutting polishing method, it is required to suppress the kerf shift and the wafer without the wafer peeling. Or pollution.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 05-335411

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-001076

Accordingly, it is an object of the present invention to provide a semiconductor wafer surface protection which can suppress kerf offset and peeling without causing damage or contamination of a semiconductor wafer in a case where a post-cutting polishing method and a stealth-cutting polishing method are applied. Adhesive tape.

As a result of the above-mentioned problem, it has been found that the above problem can be solved by providing a rigid layer in the base resin film and reducing the peeling force in a state where the peeling angle is low. The present invention has been completed based on this finding.

In order to solve the problem, the adhesive tape for protecting a surface of a semiconductor wafer according to the present invention includes a base resin film and a radiation curable adhesive layer formed on at least one side of the base resin film. The base resin film has at least one layer of tensile modulus a rigid layer of 1 to 10 GPa, after the adhesive layer is radiation-hardened, the thickness of the adhesive layer is 1.5 mm in accordance with JIS G 4305, which is treated with water-resistant abrasive paper No. 280 according to JIS R 6253. The peeling force of stainless steel (Steel Use Stainless, SUS) at a peeling angle of 30° is 0.1 to 3.0 N/25 mm.

In order to solve the above problems, the adhesive tape for protecting a surface of a semiconductor wafer according to the present invention is characterized in that it has a base resin film and is formed on at least one side of the base resin film, and has no radiation. The adhesive layer which is cured by irradiation, the base resin film has at least one rigid layer having a tensile modulus of 1 to 10 GPa, and is water-resistant abrasive paper at 550 ° C with respect to No. 280 according to JIS R 6253. The peeling force of the stainless steel (Steel Use Stainless, SUS) having a thickness of 1.5 mm as defined in JIS G 4305 at a peeling angle of 30° was 0.1 to 3.0 N/25 mm.

The adhesive tape for surface protection of a semiconductor wafer is preferably a repulsive force per unit width of 2 to 15 mN/mm which is obtained from a load load of a loop stiffness measured under the following conditions (a) to (d). .

(a) device

LOOP STIFFNESS TESTER (trade name, manufactured by Toyo Seiki Co., Ltd.)

(b) Ring (test piece) shape

Length 50mm, width 10mm, test piece direction with MD direction

(c) Pressing speed of the indenter

3.3mm/sec

(d) Pressing amount of the indenter

Press 5mm from the point of contact between the indenter and the ring

Further, in the above-mentioned adhesive tape for protecting a semiconductor wafer surface, it is preferable that the layer between the rigid layer and the adhesive layer is composed only of a layer having a tensile modulus of not more than 1 GPa, and the thickness of the adhesive layer is The total thickness of the layer having a tensile modulus of less than 1 GPa is 60 μm or less.

Further, in the above-mentioned adhesive tape for protecting a semiconductor wafer surface, it is preferable that the ratio of the insoluble component after the adhesive layer is immersed in the slurry for chemical mechanical polishing for 24 hours is 75% or more with respect to the immersion in the slurry. The slurry system for chemical mechanical polishing was obtained by dispersing 14% by weight of colloidal cerium oxide having an average particle diameter of 50 nm in an aqueous sodium hydroxide solution of pH 12.

Further, in the above-mentioned adhesive tape for protecting a surface of a semiconductor wafer, it is preferable that the adhesive layer contains a radioactive resin having an ethylenically unsaturated group in a side chain, and includes a radioactive reactivity with the radiation by irradiation of radiation. A modifier that reacts with the resin to reduce the peeling force.

Further, in the above-mentioned adhesive tape for protecting a surface of a semiconductor wafer, it is preferable that the modifier is a non-fluorenone.

Further, in order to solve the above problems, a method of manufacturing a semiconductor wafer according to the present invention includes the steps of: (a) forming a predetermined line of a semiconductor wafer from a surface of the semiconductor wafer to a semiconductor a step of forming a groove of a thickness of the wafer, and (b) bonding the surface of the semiconductor wafer on which the groove is formed to the semiconductor of any one of claims 1 to 7 a step of protecting the wafer surface protection tape and (c) a step of dicing the semiconductor wafer by grinding the back surface of the semiconductor wafer.

Further, in order to solve the above problems, a method of manufacturing a semiconductor wafer according to the present invention includes the steps of: (a) irradiating a laser inside the semiconductor wafer of a predetermined line of a semiconductor wafer by irradiation; a step of forming a modified field, (b) a step of bonding the semiconductor wafer surface protective adhesive tape according to any one of claims 1 to 7 to the surface of the semiconductor wafer before or after the step (a), and (c) a step of dicing the semiconductor wafer by grinding the back surface of the semiconductor wafer.

Moreover, the method of manufacturing the semiconductor wafer described above may include the step of performing chemical polishing in the step (c).

According to the semiconductor wafer surface protection adhesive tape of the present invention, in the back grinding step of the semiconductor wafer to which the post-cut grinding method or the invisible dicing method is applied, the dicing offset of the diced semiconductor wafer can be suppressed, and Processing without damage or contamination of the semiconductor wafer.

1‧‧‧Adhesive tape for semiconductor wafer surface protection

2‧‧‧Substrate resin film

4‧‧‧Adhesive layer

5‧‧‧Semiconductor wafer

6‧‧‧Cut tape

7‧‧‧ditch

8‧‧‧ grinding device

9‧‧‧Ring frame

11‧‧‧ wafer

[Fig. 1] Fig. 1 is a cross-sectional view schematically showing the structure of an adhesive tape for protecting a surface of a semiconductor wafer according to an embodiment of the present invention.

[Fig. 2] schematically shows an embodiment using the present invention A cross-sectional view of a back grinding step of an adhesive tape for semiconductor wafer surface protection.

[Fig. 3] A cross-sectional view schematically showing a back surface polishing step of an adhesive tape for semiconductor wafer surface protection according to an embodiment of the present invention.

[Fig. 4] is a cross-sectional view schematically showing a cutting step after the back surface polishing step of the adhesive tape for semiconductor wafer surface protection according to the embodiment of the present invention.

[Fig. 5] is a cross-sectional view schematically showing a cutting step after the back surface polishing step of the adhesive tape for semiconductor wafer surface protection according to the embodiment of the present invention.

[Fig. 6] Fig. 6 is a cross-sectional view schematically showing an expansion step after the back surface polishing step of the adhesive tape for semiconductor wafer surface protection according to the embodiment of the present invention.

[Fig. 7] is a cross-sectional view schematically showing a pickup step after the back surface polishing step of the adhesive tape for semiconductor wafer surface protection according to the embodiment of the present invention.

[Fig. 8] is a cross-sectional view showing the position, shape, and size of a circuit pattern of a semiconductor wafer and a dummy step of a groove provided on a line to be cut, which are used in the evaluation of the examples and the comparative examples.

[Fig. 9] is an explanatory view showing an observation point of the kerf width in the evaluation of the examples and the comparative examples.

[Fig. 10] is an explanatory view for explaining a method of measuring the peeling force at a peeling angle of 30° of the adhesive tape for semiconductor wafer surface protection according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view schematically showing the structure of an adhesive tape 1 for semiconductor wafer surface protection according to an embodiment of the present invention.

As shown in Fig. 1, the adhesive tape 1 for semiconductor wafer surface protection of the present embodiment has a base resin 2, and an adhesive layer 4 is provided on at least one side of the base resin film 2. The adhesive layer 4 may be laminated on the side of the adhesive layer 4 so that the release-treated surface of the release film (not shown) whose surface is subjected to release treatment may be provided on the adhesive layer 4 as needed.

(Substrate Resin Film 2)

As the base resin film 2 of the adhesive tape 1 for semiconductor wafer surface protection of the present invention, a well-known plastic, rubber or the like can be used. In the case of using the radiation curable composition in the adhesive layer 4, the base resin film 2 is preferably one in which the transmittance of the radiation having a wavelength at which the composition is cured is preferably selected. Here, the term "radiation" refers to, for example, ultraviolet light, or laser light, or an ionizing radiation such as an electron beam. Hereinafter, these terms are collectively referred to as radiation.

Examples of the substrate resin film 2 which can be selected are polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer. a homopolymer or copolymer of an α -olefin such as an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-acrylic acid copolymer, an ionic polymer, or the like, or a mixture thereof, polyethylene terephthalate Engineering plastics, polyurethanes, styrene-ethylene-butylene or pentene copolymers, polyamines such as diesters, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, etc. a thermoplastic elastomer such as a polyol copolymer, and a mixture thereof. Further, it is also possible to use these to be multi-layered.

The base resin film 2 of the adhesive tape 1 for semiconductor wafer surface protection of the present embodiment is used for normal use in order to reduce the amount of kerf offset in the case of the post-cut polishing method and the invisible dicing polishing method. In the case of the back grinding step, warpage of the semiconductor wafer 5 (see FIG. 2) is suppressed, and a rigid layer having a tensile modulus of 1 to 10 GPa is an essential element. Examples of the resin constituting the rigid layer include a polyester film such as polyethylene terephthalate.

However, if the rigid layer is provided, the flexibility is lowered. Therefore, it is difficult to peel off the semiconductor wafer surface protective pressure-sensitive adhesive tape 1, and it is easy to cause breakage of the semiconductor wafer 5 or adhesive residue during peeling. Based on this, the thickness of the rigid film is suitably 10 to 100 μm, preferably 10 to 50 μm, more preferably 20 to 40 μm. Further, the repulsive force of the ring stiffness as an index of the bendability is preferably 2 to 15 mN/25 mm or less, more preferably 5 to 13 mN/25 mm. Here, the repulsive force of the ring stiffness is a repulsive force per unit width obtained from the load load of the ring stiffness measured under the following conditions (a) to (d).

(a) device

LOOP STIFFNESS TESTER (trade name, manufactured by Toyo Seiki Co., Ltd.)

(b) Ring (test piece) shape

Length 50mm, width 10mm, test piece direction with MD direction

(c) Pressing speed of the indenter

3.3mm/sec

(d) Pressing amount of the indenter

Press 5mm from the point of contact between the indenter and the ring

Further, the base resin film 2 in which the polyolefin layer is laminated on one side or both sides of the rigid layer is used for imparting cushioning properties on the back surface of the semiconductor wafer 5 and unevenness on the surface of the semiconductor wafer 5. The improvement of the embedding property of the adhesive layer 4 is further improved from the viewpoint of improving the adhesion of the heat seal used when the semiconductor wafer surface protective adhesive tape 1 is peeled off. As the resin suitable for the laminated polyolefin layer, low density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, or the like is preferable.

As a method of laminating the respective layers to form the base resin film 2, for example, a known one such as a bonding agent or a co-extrusion using an adhesive or an adhesive can be applied.

The surface of the base resin film 2 on the side where the pressure-sensitive adhesive layer 4 is provided may be subjected to a treatment such as a corona treatment or a primer layer in order to improve the adhesion to the pressure-sensitive adhesive layer 4. Further, it is preferable that the surface of the base resin film 2 on the side where the pressure-sensitive adhesive layer 4 is not provided is embossed or lubricant-coated, whereby the agglomeration of the surface protective adhesive tape of the present invention can be obtained. Prevent the effects of etc.

(adhesive layer 4)

As shown in FIG. 1, the semiconductor wafer surface protection of this embodiment The adhesive layer 4 is formed on the base resin film 2 by the adhesive tape 1.

The adhesive composition constituting the adhesive layer 4 can sufficiently maintain the adhesion to the semiconductor wafer 5 when the semiconductor wafer 5 is ground, and does not occur when the semiconductor wafer surface protective adhesive tape 1 is peeled off. The damage of the semiconductor wafer 5 is not particularly limited, but it is preferable to select a low peeling force at a low angle as described below. The polymer of the main component (adhesive matrix resin) is preferably a (meth)acrylic resin. By using a polymer having a (meth)acrylic resin as a main component, it is easy to control the adhesion, and the elastic modulus and the like can be controlled.

From the viewpoint of the releasability, it is preferred to use a radiation curable adhesive as the adhesive composition constituting the adhesive layer 4. In order to harden under irradiation of radiation, the resin such as the adhesive matrix resin has an ethylenically unsaturated group (non-aromatic carbon-carbon double bond), or is used in an adhesive matrix resin having an ethylenically unsaturated group. Compound. In the present invention, from the viewpoint of the releasability, a resin such as an adhesive matrix resin is preferably used as a resin having an ethylenically unsaturated group in its side chain. Moreover, it is preferable to contain a photopolymerization initiator and a crosslinking agent in the adhesive composition, and it is preferable to contain a crosslinking agent in order to adjust the elastic modulus or adhesive force of the adhesive layer 4.

As the adhesive composition constituting the adhesive layer 4, in the case of using a so-called pressure-sensitive adhesive which is hardened by irradiation with radiation, it is also possible to replace the irradiation of radiation, and at the time of peeling, for example, by applying 50. The heat around °C reduces the peeling force. As such a pressure-sensitive adhesive, a constituent unit derived from an alkyl (meth) acrylate monomer, and 2-hydroxypropyl acrylate, 2-hydroxyethyl (meth) acrylate may be used. and/ Or a constituent unit derived from 2-hydroxybutyl acrylate, and a copolymer comprising a constituent unit derived from the alkyl (meth) acrylate monomer is obtained by crosslinking an isocyanate compound.

[Resin having ethylenically unsaturated group]

The resin having an ethylenically unsaturated group is preferably a (meth)acrylic resin, although it may be any. The iodine value as an index of the amount of the double bond contained in the resin is preferably from 0.5 to 20. The iodine value is preferably from 0.8 to 10. When the iodine value is 0.5 or more, the effect of reducing the adhesion after radiation irradiation can be obtained, and if the iodine value is 20 or less, excessive radiation hardening can be prevented. Further, the resin having an ethylenically unsaturated group preferably has a glass transition temperature (Tg) of -70 ° C to 0 ° C. When the glass transition temperature (Tg) is -70 ° C or more, heat resistance to heat accompanying the processing step of the semiconductor wafer 5 increases.

The resin having an ethylenically unsaturated group may be produced by any method, but it is preferably a (meth)acrylic resin having a functional group ( α ) in a side chain and having an ethylenically unsaturated group and A method in which a compound of a functional group (β) in which a functional group ( α ) in the resin is reacted is introduced, and an ethylenically unsaturated group is introduced into a side chain of the (meth)acrylic resin.

The ethylenically unsaturated group may be any of the groups, but is preferably a (meth) acrylonitrile group, a (meth) propylene fluorenyl group, a (meth) acryl amide group, an allyl group, or a 1- A propylene group, a vinyl group (including styrene or substituted styrene), more preferably a (meth) acrylonitrile group or a (meth) propylene fluorenyl group. The functional group (β) which reacts with the functional group ( α ) may, for example, be a carboxyl group, a hydroxyl group, an amine group, a mercapto group, a cyclic acid anhydride group, an epoxy group or an isocyanate group.

Here, in the case where the functional group of one of the functional group ( α ) and the functional group (β) is a carboxyl group, a hydroxyl group, an amine group, a mercapto group or a cyclic acid anhydride group, the other functional group may be an epoxy group. When the functional group of one of the group and the isocyanate group is a cyclic acid anhydride group, the other functional group may, for example, be a carboxyl group, a hydroxyl group, an amine group or a fluorenyl group. Further, when one of the functional groups is an epoxy group, the other functional group may be an epoxy group.

The (meth)acrylic resin having a functional group ( α ) in a side chain is obtained by polymerizing a (meth) acrylate having a functional group ( α ), acrylic acid or (meth) acrylamide. The functional group ( α ) may, for example, be a carboxyl group, a hydroxyl group, an amine group, a mercapto group, a cyclic acid anhydride group, an epoxy group or an isocyanate group, and is preferably a carboxyl group or a hydroxyl group, and particularly preferably a hydroxyl group.

As such a single system, acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylate, 2-hydroxyalkyl methacrylate , diol monoacrylates, diol monomethacrylates, N-methylol acrylamide, N-methylol methacrylamide, allyl alcohol, N-alkylamine ethyl acrylate , N-alkylamine ethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride, phthalic anhydride, epoxy propyl acrylate Ester, glycidyl methacrylate, allyl epoxide propyl ether, a part of an isocyanate group of a polyisocyanate compound is subjected to an amine group with a monomer having a hydroxyl group or a carboxyl group and a radiation hardening carbon-carbon double bond Acidifiers, etc. Among these, acrylic acid, methacrylic acid, 2-hydroxyalkyl acrylate, 2-hydroxyalkyl methacrylate, and epoxy propyl group are preferred. Acrylate, propylene methacrylate, more preferably acrylic acid, methacrylic acid, 2-hydroxyalkyl acrylate, 2-hydroxyalkyl methacrylate, more preferably 2-hydroxyalkyl Acrylates, 2-hydroxyalkyl methacrylates.

The resin having an ethylenically unsaturated group is preferably a copolymer with other monomers such as (meth) acrylate, together with the above monomers. Examples of the (meth) acrylate include methacrylate, ethacrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, and n- Hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, methacrylate hexyl acrylate, and methacrylate corresponding thereto . The (meth) acrylate may be used alone or in combination of two or more. It is preferred that the carbon number of the alcohol portion is 5 or less and the carbon number is 6 to 12. The resin having an ethylenically unsaturated group is preferably a copolymer of (meth)acrylic acid in addition to (meth) acrylate.

The polymerization reaction of a resin having an ethylenically unsaturated group, particularly a resin having an ethylenically unsaturated group, may be any of solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. A reaction in which a (meth)acrylic resin having a functional group ( α ) in a side chain is reacted with a compound having an ethylenically unsaturated group and a functional group (β) reactive with a functional group ( α ) in the above resin The reaction can be carried out by leaving one of them excessive, and the unreacted functional group remains, and the desired adhesive property and elastic modulus are adjusted.

As a polymerization initiator, α,α'-azobisisodin is usually used. A radical generator such as an azobis system such as a nitrile or an organic peroxide such as benzamidine peroxide. In this case, a catalyst or a polymerization inhibitor may be used in combination as needed, and a resin having a desired molecular weight can be obtained by adjusting the polymerization temperature and the polymerization time. Further, it is preferable to use a solvent of a mercaptan or a carbon tetrachloride type for adjusting the molecular weight.

The average molecular weight of the resin having an ethylenically unsaturated group is preferably from 250,000 to 1,500,000, more preferably from 700,000 to 1,200,000. By reducing the low molecular weight component, surface contamination of the semiconductor wafer 5 can be suppressed. For example, it is preferable to set the molecular weight of 100,000 or less to 10% or less of the total. When the molecular weight exceeds 1.5 million, gelation may occur during synthesis and coating. In addition, when the resin having an ethylenically unsaturated group has an OH group having a hydroxyl group content of 5 to 100 mgKOH/g, the risk of peeling failure can be further reduced by reducing the adhesion after radiation irradiation. good.

A compound having a functional group (β) having an ethylenically unsaturated group and a functional group ( α ) will be described. The ethylenically unsaturated group is preferably a group as described above, and the preferred range is also the same. The functional group ( β ) which reacts with the functional group ( α ) may be exemplified by the groups described above. Particularly preferred as the functional group (β) is an isocyanate group.

Examples of the compound having a functional group (β) having an ethylenically unsaturated group and a functional group ( α ) include a compound having a monomer having a functional group ( α ) and an isocyanate group at the alcohol moiety (methyl group). The acrylate is preferably a (meth) acrylate having an isocyanate group at the alcohol moiety. The (meth) acrylate having an isocyanate group in the alcohol moiety preferably has an isocyanate group at the terminal of the alcohol moiety, and the carbon number other than the isocyanate group of the alcohol moiety is preferably 2 to 8, and the alcohol moiety is straight. Chain alkyl is preferred. The (meth) acrylate having an isocyanate group in the alcohol moiety is preferably, for example, 2-isocyanatoethyl acrylate or 2-isocyanatoethyl methacrylate.

[crosslinking agent]

The crosslinking agent is preferably a polyisocyanate, a melamine/formaldehyde resin or an epoxy compound having two or more epoxy groups, and particularly preferably a polyisocyanate. The crosslinking agent may be used singly or in combination of two or more. The crosslinking agent can enhance the cohesive force of the adhesive after the application of the adhesive by crosslinking the resin polymer.

Examples of the polyisocyanate type include hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane. Isocyanate, 2,4'-dicyclohexylmethane diisocyanate, diazonic acid diisocyanate, isocyanuric acid triisocyanate, 4,4'-diphenylmethane diisocyanate, methylphenyl diisocyanate, xylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-[2,2-bis(4-phenoxyphenyl)propane] diisocyanate, etc., specifically, CORONATE L can be used as a commercial product. (made by Nippon Polyurethane Co., Ltd.), etc.

For the melamine/formaldehyde resin, a commercially available product such as NIKALAC MX-45 (manufactured by SANWA CHEMICAL Co., Ltd.), Melan (manufactured by Hitachi Chemical Co., Ltd.), or the like can be used. Further, TETRAD-X (manufactured by Mitsubishi Chemical Corporation) can be used as the epoxy resin system. Wait.

The amount of the crosslinking agent added is preferably 0.1 to 20 parts by mass, more preferably 1.0 to 10 parts by mass, based on 100 parts by mass of the resin having an ethylenically unsaturated group, and is blended with an ethylenically unsaturated group. The number of functional groups of the resin is adjusted in order to obtain a desired adhesive property or elastic modulus. When the amount of the crosslinking agent is less than 0.1 part by mass, the cohesive force-improving effect tends to be insufficient. When the amount of the crosslinking agent is more than 20 parts by mass, the curing reaction may be rapidly performed during the bonding and coating operation of the adhesive, and the formation of the crosslinking is performed. The tendency of the joint structure, therefore, may damage the operational nature.

[Photopolymerization initiator]

In the case where the radiation-curable adhesive is selected as the adhesive layer 4, a photopolymerization initiator may be contained as needed. The photopolymerization initiator is not particularly limited as long as it is reacted by radiation passing through the substrate, and a conventionally known one can be used. For example, diphenyl ketone, 4,4'-dimethylaminodiphenyl ketone, 4,4'-diethylaminodiphenyl ketone, 4,4'-dichlorodiphenyl ketone Ethyl ketones such as diphenyl ketones, acetophenones, diethoxyacetophenones, oximes such as 2-ethyl hydrazine and t-butyl hydrazine, 2-chlorothioxene Ketone, benzoin ethyl ether, benzoin isopropyl ether, benzyl, 2,4,5-triarylimidazole dimer (octyl dimer), acridine compound, mercaptophosphine oxide, etc. The system may be used alone or in combination of two or more. The amount of the photopolymerization initiator to be added is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the resin having an ethylenically unsaturated group.

[Other Additives]

In the adhesive layer 4, a tackifier, an adhesive adjuster, a surfactant, or the like may be blended as needed, or a modifier or the like. Further, an inorganic compound filler may be added as appropriate. In the present invention, it is also preferable to add a modifier in terms of peelability. Examples of the modifier include an anthrone compound, a fluorine compound, a compound containing a long-chain alkyl group, and the like, and the peeling force at a low angle is lowered by adding, and the contact angle with water is increased, thereby making it possible to Dust immersion inhibition is suppressed. In order to prevent the transfer agent from being transferred to the surface of the semiconductor wafer 5, the modifier is preferably a compound having an ethylenically unsaturated group, and more preferably, the binder matrix resin is a resin having an ethylenically unsaturated group in the side chain. . Specific examples of the modifier having an ethylenically unsaturated group include Ebecryl 360 (manufactured by DAICEL-ALLNEX Co., Ltd.) as a fluorenone acrylate or a fluorine-based surface modifier. MEGAFAC RS-72-K (manufactured by DIC Corporation). From the viewpoint of the influence on the surface of the semiconductor wafer 5, a fluorine-based compound is more preferable.

The adhesive layer 4 can be formed, for example, by applying the above-described adhesive composition to a release film, drying it, and transferring it onto the base resin film 2. The thickness of the adhesive layer 4 is preferably from 1 to 60 μm.

Here, in the post-cut polishing method and the invisible post-cut polishing method, since the gap exists between the wafers in the back surface grinding of the semiconductor wafer, after performing CMP (chemical mechanical polishing) or etching, Grinding treatment, there is a slurry Adhesives that contaminate semiconductor wafers or adhesive tapes on the surface of semiconductor wafers erode the slurry and contaminate semiconductor wafers with brittle adhesives. Further, in the post-cutting polishing method and the invisible post-cutting polishing method, since the semiconductor wafer 5 is wafer 11 in the middle of the grinding, it is easier to cause the semiconductor wafer due to the grinding dust than the usual grinding. 5 surface pollution.

Therefore, the adhesion of the surface protective tape to the surface of the semiconductor wafer 5 is more required. However, in the method of thickening the adhesive layer 4 in order to improve the adhesion as is generally known, it is known that the wafer 11 vibrates in the depth direction during the grinding after the dicing method or the post-cut dicing method. Therefore, it becomes a state in which dust immersion easily occurs. Therefore, the adhesive layer 4 is preferably thinner, more preferably 5 to 30 μm, and the layer formed between the rigid layer and the adhesive layer 4 is only composed of a layer having a tensile modulus of less than 1 GPa. In the case of the composition, the thickness of the adhesive layer 4 and the thickness of the layer having a tensile modulus of not more than 1 GPa are preferably 5 to 60 μm, more preferably 5 to 30 μm. Since the layer formed between the rigid layer and the adhesive layer 4 is composed of only a layer having a tensile modulus of less than 1 GPa, in the case of having a plurality of rigid layers, it is formed in the closest adhesive. The layer between the rigid layer of the layer 4 and the adhesive layer 4 may be composed of only a layer having a tensile modulus of less than 1 GPa. Examples of the layer having a tensile modulus of less than 1 GPa include a layer constituting a base resin film other than the rigid layer, or an adhesive layer for bonding a plurality of layers constituting the base resin film.

Also, the storage modulus of the adhesive is Preferably, it is 0.01 to 0.1 MPa at 25 ° C, more preferably 0.02 to 0.1 MPa at 50 ° C. By setting the storage modulus of the adhesive layer 4 to this range, even if the thickness of the adhesive layer 4 is small, it is easy to prevent dust from entering, and it is also difficult to cause adhesive residue or wafer peeling at the time of peeling. Further, the adhesive layer 4 may have a structure in which a plurality of adhesive layers 4 are laminated.

Moreover, it is preferable that the adhesive layer 4 is a ratio (gel fraction) of the insoluble matter after immersing in the slurry for chemical polishing for 24 hours on the back surface of the semiconductor wafer 5 with respect to the immersion in the slurry. More than 75%, more preferably more than 90%. By setting the gel fraction of the adhesive layer 4 to the slurry to 75% or more, it is possible to contaminate the surface of the wafer by eroding the adhesive from the slurry immersed between the sized wafers 11. For suppression. For the slurry, for example, a slurry for chemical mechanical polishing in which 14% by weight of colloidal ceria having an average particle diameter of 50 nm is dispersed in a sodium hydroxide aqueous solution of pH 12 can be used.

Further, in the adhesive tape 1 for semiconductor wafer surface protection of the present invention, when the adhesive layer 4 is a radiation-curable adhesive layer 4, after the radiation irradiation, the adhesive layer 4 is a pressure-sensitive adhesive layer. The case of 4 is that the peeling force at a peeling angle of 30° and a stretching speed of 20 mm/min must be 0.1 to 3.0 N/25 mm, preferably 0.5 to 1.8 N/25 mm, under heating at 50 °C. Even when the radiation-curable adhesive layer 4 is used as the adhesive layer 4, the peeling force can be lowered by peeling under heating conditions of 50 ° C after radiation hardening, in which case it means heating at 50 ° C. The peeling force underneath. If the peeling force is less than 0.1 N/25 mm, the back surface of the semiconductor wafer 5 is ground and sliced into a wafer. After that, the wafer 11 is likely to be displaced in the next step of transport. When the thickness exceeds 3.0 N/25 mm, the wafer 11 is easily peeled off when the semiconductor wafer surface protective adhesive tape 1 is peeled off. The wafer peeling off from the dicing tape 6 or the dicing die film bonded to the back surface of the semiconductor wafer 5 or the residue of the adhesive for the semiconductor wafer surface protecting adhesive tape 1 adheres to the surface of the semiconductor wafer 5. Residue of glue.

The adhesive tape of the semiconductor wafer surface protection adhesive tape 1 of the semiconductor wafer 5 is adhered to the end portion of the adhesive tape 1 for semiconductor wafer surface protection, and is peeled off from the end portion. Since the peeling of the semiconductor wafer surface protective adhesive tape 1 and the semiconductor wafer 5 is an acute angle at the initial stage of peeling, it peels close to the surface, and becomes a large peeling force compared with 90 degree peeling etc.. For example, in the adhesive tape 1 for semiconductor wafer surface protection of Comparative Example 1 to be described later, the peeling force at 90° peeling is 0.4 N/25 mm, but the peeling force at 30° peeling is 3.6 N/25 mm. If the thin semiconductor wafer 5 after the grinding or the semiconductor wafer 5 that has been wafer 11 is peeled off in this state, the risk of wafer cracking or wafer peeling is extremely high. In particular, since the base resin film 2 has a rigid layer, the bendability is poor, and the peeling opening is difficult to grip, so that wafer cracking or the like is more likely to occur.

Here, the peeling angle of 30° of the present invention means the angle of peeling of the actual adherend and the semiconductor wafer surface protective adhesive tape 1 with respect to the angle of the stretched direction of the object to be adhered to the surface protection of the semiconductor wafer. The rigidity of the adhesive tape 1 changes.

The peeling force at a peeling angle of 30° is obtained from the semiconductor The adhesive tape 1 for wafer surface protection is a test piece having a width of 25 mm and a length of 300 mm, and the sample is processed into a stainless steel having a thickness of 1.5 mm according to JIS G 4305, which is treated with water-resistant abrasive paper No. 280 according to JIS R 6253. On the (Steel Use Stainless, SUS) plate, the test piece was pressed back and forth three times with a rubber roller of 2 kg to allow the adhesive to be placed in the radiation hardening type by radiation hardening for one hour, and the adhesive was In the case of the pressure-sensitive type, the SUS plate was heated to a temperature of 50 ° C, and a tensile tester suitable for JIS B 7721 having a measurement value of 15 to 85% of the capacity was used, and the tensile speed was 20 mm/min. The film was stretched and peeled under the conditions of a temperature of 25 ° C and a relative humidity of 50%, and was measured by measuring the peeling force when the peeling angle θ was 30° (see Fig. 10).

In order to reduce the peeling force at a peeling angle of 30°, it is important to reduce the flexibility of the adhesive tape 1 for semiconductor wafer surface protection and to prevent local extension of the adhesive portion with the object. Specifically, as described above, the rigidity and thickness of the base resin film 2 can be adjusted as described above, and the local extension can be made by the thickness of the rigid layer or the addition of the modified layer, and other adhesive composition. Wait and adjust.

(release film)

Further, in the surface protective adhesive tape of the present invention, the release film is provided on the adhesive layer 4 as needed. The release film is also referred to as a spacer, a release layer, and a release liner, and is provided for the purpose of protecting the adhesive layer 4 for the purpose of smoothing the adhesive. Examples of the constituent material of the release film include polyethylene, polypropylene, and polyethylene terephthalate. A resin film or paper. In order to improve the peelability from the release agent layer 4, the surface of the release film may be subjected to a release treatment such as an anthrone treatment, a long-chain alkyl treatment, or a fluorine treatment. Further, it is preferable to carry out ultraviolet ray prevention treatment as needed to prevent the adhesive layer 4 from reacting due to exposure of an unexpected ultraviolet ray such as ultraviolet rays. The thickness of the release film is usually from 10 to 100 μm, preferably from about 25 to 50 μm.

<Use>

The use of the wafer processing tape 1 of the present invention can be suitably used in a method of manufacturing a semiconductor wafer 5 using a post-cut polishing method or a stealth dicing polishing method, for example, a method of manufacturing the semiconductor wafer 5 described below. (A)~(B).

The manufacturing method (A) of the semiconductor wafer 5 includes a method of manufacturing the semiconductor wafer 5 of the following steps: (a) forming a predetermined line of the semiconductor wafer 5 from the surface of the semiconductor wafer 5 to the semiconductor a step of the groove 7 having a thickness of the wafer 5; (b) a step of bonding the above-mentioned semiconductor wafer surface protective adhesive tape 1 to the surface of the semiconductor wafer 5 on which the groove 7 is formed; (c) by grinding the aforementioned The step of thinning the semiconductor wafer 5 on the back surface of the semiconductor wafer 5.

The manufacturing method (B) of the semiconductor wafer 5 is characterized in that the semiconductor wafer 5 is manufactured by the following steps: (a) the semiconductor crystal by the predetermined line of the semiconductor wafer 5 a step of irradiating the laser light inside the circle 5 to form a modified field; (b) a step of bonding the above-mentioned semiconductor wafer surface protective adhesive tape 1 to the surface of the semiconductor wafer 5 before or after the step (a); (c) a step of thinning the semiconductor wafer 5 by grinding the back surface of the semiconductor wafer 5.

<How to use>

Next, an example of a method of using the semiconductor wafer surface protection adhesive tape 1 of the present invention, that is, a method of processing the semiconductor wafer 5 will be described. First, as shown in FIG. 2, a groove 7 (ditching step) having a depth equal to or greater than the thickness of the final product is formed on the semiconductor wafer 5 from the surface side of the semiconductor wafer 5 by using a blade (not shown) or a laser. Then, on the surface of the semiconductor wafer 5 on which the circuit pattern is formed, the adhesive layer 4 of the adhesive tape 1 for semiconductor wafer surface protection is bonded (protective tape bonding step).

Next, as shown in FIG. 3(A), the semiconductor wafer 5 on which the groove 7 is formed is ground by the grinding device 8 by grinding the back surface, and as shown in FIG. 3(B), the grinding is performed. Arrived in the ditch 7. Thereby, the semiconductor wafer 5 is diced into the wafer 11. If necessary, the polishing or etching treatment is performed for the purpose of improving the bending strength of the semiconductor wafer 5 after the grinding step. Chemical mechanical polishing (CMP) can be used as the polishing system. At this time, if the gel fraction of the adhesive layer 4 with respect to the slurry is 75%, it is possible to contaminate the surface of the wafer by etching the adhesive from the slurry immersed between the sized wafers 11. inhibition.

After the grinding and grinding steps are completed, as shown in Figure 4 In general, the dicing tape 6 or the dicing die film is bonded to the back surface of the semiconductor wafer 5, and the annular frame 9 is bonded to the outer peripheral portion of the dicing tape 6. Thereafter, as shown in FIG. 5, the semiconductor wafer surface protection adhesive tape 1 is peeled off. In this case, the adhesive tape 1 for semiconductor wafer surface protection of the present embodiment has a peeling force of 0.1 to 3.0 N/25 mm at a peeling angle of 30° and a tensile speed of 20 mm/min, so that the semiconductor crystal can be reduced. After the back surface of the circle 5 is ground and the wafer is formed into the wafer 11, the wafer 11 is displaced (intercept offset) during the next step of transportation, and the occurrence of breakage of the wafer including the wafer peeling can be reduced.

Then, for example, as shown in Fig. 6, the dicing tape 6 to which the semiconductor wafer 5 and the annular frame 9 are bonded is placed on a mounting table (not shown) of the expansion device to bring the ring frame 9 In a fixed state, the lifting member 10 of the extension device is raised to expand the cutting tape 6.

Next, as shown in Fig. 7, the wafer 11 can be lifted by lifting the pin 12 from the back side of the dicing tape 6, and the chuck 13 can be sucked and picked up to obtain the semiconductor wafer 11.

In the above description, the method of using the adhesive tape 1 for semiconductor wafer surface protection using the post-cut polishing method will be described. However, the post-cut polishing method may be used instead of the post-cut polishing method. In the case where the invisible dicing polishing method is used, instead of the grooving step, a reforming field forming step of forming a modified field by irradiating a laser inside the semiconductor wafer 5 is performed. The reforming domain forming step can also be carried out after the protective tape bonding step.

<Example>

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

The adhesive composition was prepared as described below, and an adhesive tape for surface protection of a semiconductor wafer was produced by the following method to evaluate the performance.

[Modulation of adhesive layer composition]

[Adhesive layer composition 2A]

For 100 parts by mass of a copolymer composed of 83 parts by mass of 2-ethylhexyl acrylate, 16 parts by mass of 2-hydroxyacrylate, and 1 part by mass of methacrylic acid, methacryloxyethyl group as a radiation reactive group was used. 10 parts by mass of the isocyanate was reacted, and 0.8 parts by mass of CORONATE L (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a polyisocyanate, and SPEEDCURE BKL (trade name, manufactured by DKSH Japan Co., Ltd.) as a photopolymerization initiator were added. 5.0 parts by mass was mixed to obtain an adhesive composition 2A.

[Adhesive layer composition 2B]

The adhesive composition 2B was obtained in the same manner as the adhesive composition 2A except that 2 parts by mass of MEGAFAC RS-72-K (trade name, manufactured by DIC Corporation) was added as a fluorine-based modifier.

[Adhesive layer composition 2C]

In addition to adding 0.2 parts by mass of Ebecryl as an anthrone-based modifier The adhesive composition 2C was obtained in the same manner as the adhesive composition 2A except for 360 (trade name, manufactured by DAICEL-ALLNEX Co., Ltd.).

[Adhesive layer composition 2D]

5-functional urethane acrylate oligomerization is added to 100 parts by mass of a copolymer composed of 80 parts by mass of 2-ethylhexyl acrylate, 19 parts by mass of 2-hydroxyacrylate, and 1 part by mass of methacrylic acid. 80 parts by mass of a compound, 20 parts by mass of a trifunctional urethane acrylate oligomer, and 5.0 parts by mass of CORONATE L (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a polyisocyanate, as a photopolymerization initiator 4.0 parts by mass of SPEEDCURE BKL (trade name, manufactured by DKSH Japan Co., Ltd.) was mixed to obtain an adhesive composition 2D.

[Adhesive layer composition 2E]

5-functional urethane acrylate oligomerization is added to 100 parts by mass of a copolymer composed of 80 parts by mass of 2-ethylhexyl acrylate, 19 parts by mass of 2-hydroxyacrylate, and 1 part by mass of methacrylic acid. 30 parts by mass of a compound, 30 parts by mass of a trifunctional urethane acrylate oligomer, and 5.0 parts by mass of CORONATE L (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a polyisocyanate, as a photopolymerization initiator 4.0 parts by mass of SPEEDCURE BKL (trade name, manufactured by DKSH Japan Co., Ltd.) was mixed to obtain an adhesive composition 2D.

[Adhesive layer composition 2F]

CORONATE L (trade name, Nippon Polyurethane) as a polyisocyanate is added to 100 parts by mass of a copolymer composed of 80 parts by mass of 2-ethylhexyl acrylate, 19 parts by mass of 2-hydroxyacrylate, and 1 part by mass of methacrylic acid. 3.0 parts by mass of Industry Co., Ltd. was mixed to obtain an adhesive composition 2E.

[Production of adhesive tape for semiconductor wafer surface protection]

[Example 1]

A polyethylene terephthalate film having a thickness of 38 μm and a tensile modulus of 2 GPa on both sides and a polypropylene film having a thickness of 40 μm were bonded together using a 2 μm adhesive to obtain a laminated substrate of 80 μm in total. Resin film. Next, the adhesive composition 2B was applied to a spacer of polyethylene terephthalate (PET) having a thickness of 38 μm so that the film thickness after drying became 30 μm, and dried, and then 80 μm. The polyethylene terephthalate of the laminated base resin film was bonded to each other to obtain a semiconductor wafer surface protective adhesive tape having a thickness of 110 μm.

[Embodiment 2]

A semiconductor wafer surface protective adhesive tape having a thickness of 110 μm was obtained in the same manner as in Example 1 except that 2C was used as the adhesive composition.

[Example 3]

A semiconductor wafer surface protective adhesive tape having a thickness of 110 μm was obtained in the same manner as in Example 1 except that 2A was used as the adhesive composition.

[Example 4]

A semiconductor wafer surface protective adhesive tape having a thickness of 110 μm was obtained in the same manner as in Example 1 except that 2D was used as the adhesive composition.

[Example 5]

On both sides of a polyethylene terephthalate film having a thickness of 50 μm and a tensile modulus of 2 GPa, a low-density polyethylene film was extruded to have a thickness of 30 μm, and electricity was formed on one side of the low-density polyethylene film. The mixture was treated with a halo to obtain a laminated base resin film of 110 μm in total. Next, the adhesive composition 2A was applied to a spacer of polyethylene terephthalate (PET) having a thickness of 38 μm so that the film thickness after drying became 20 μm, and dried, and then 110 μm. The corona-treated low-density polyethylene surface of the laminated base resin film was bonded to each other to obtain a semiconductor wafer surface protective adhesive tape having a thickness of 130 μm.

[Embodiment 6]

In addition to the polyethylene terephthalate film of the laminated base resin film, polyethylene terephthalate having a thickness of 25 μm and a tensile modulus of 2 GPa was prepared. A semiconductor wafer surface protective adhesive tape having a thickness of 105 μm was obtained in the same manner as in Example 5 except for the film.

[Embodiment 7]

A low-density polyethylene film was extruded on one side of a polyethylene terephthalate film having a thickness of 50 μm and a tensile modulus of 2 GPa on both sides to have a thickness of 10 μm to obtain a thickness of 60 μm. A laminated resin film is laminated. Next, the adhesive composition 2F was applied to a spacer of polyethylene terephthalate (PET) having a thickness of 38 μm so that the film thickness after drying became 50 μm, and dried, and then dried at 60 μm. The polyethylene terephthalate of the laminated base resin film was surface-bonded. Further, on the spacer of polyethylene terephthalate (PET) having a thickness of 38 μm, the adhesive composition 2C was applied so as to have a film thickness after drying of 20 μm, dried, and then bonded thereto. The spacer of the above-mentioned intermediate was peeled off from the adhesive composition 2F surface to obtain a semiconductor wafer surface protective adhesive tape having a thickness of 130 μm.

[Comparative Example 1]

A low-density polyethylene film is extruded on one side of a polyethylene terephthalate base resin film having a thickness of 100 μm and a tensile modulus of 2 GPa on both sides to have a thickness of 10 μm. A laminated base resin film having a thickness of 110 μm was obtained. Next, the adhesive composition 2F was applied to a spacer of polyethylene terephthalate (PET) having a thickness of 38 μm so that the film thickness after drying was 20 μm, and dried. The polyethylene terephthalate film of the above-mentioned 110 μm laminated base film was bonded. Further, on the spacer of polyethylene terephthalate (PET) having a thickness of 38 μm, the adhesive composition 2F was applied so as to have a film thickness after drying of 20 μm, and dried, and then bonded thereto. The spacer of the above-mentioned intermediate was peeled off from the adhesive composition 2F surface to obtain a semiconductor wafer surface protective adhesive tape having a thickness of 150 μm.

[Comparative Example 2]

A film of a low-density polyethylene resin of 30 μm and an ethylene-vinyl acetate copolymer of 80 μm and a thickness of 110 μm and a tensile modulus of 0.2 GPa were prepared by co-extrusion to form an ethylene-vinyl acetate copolymer. The surface is corona treated. Next, the adhesive composition 2C was applied to a spacer of polyethylene terephthalate (PET) having a thickness of 38 μm so that the film thickness after drying became 20 μm, and dried, and then 110 μm. The corona-treated ethylene-vinyl acetate copolymer of the laminated base resin film was surface-bonded to obtain a semiconductor wafer surface protective adhesive tape having a thickness of 130 μm.

[Comparative Example 3]

By co-extrusion film formation, a laminated base resin film of a high-density polyethylene resin of 30 μm and an ethylene-vinyl acetate copolymer of 80 μm and a thickness of 110 μm and a tensile modulus of 0.4 GPa was produced in an ethylene-vinyl acetate copolymer. The surface is corona treated. Next, on a spacer of polyethylene terephthalate (PET) having a thickness of 38 μm so that the film thickness after drying became 20 μm. The adhesive composition 2E was applied, and after drying, the surface of the 110 μm laminated resin film of the corona-treated ethylene-vinyl acetate copolymer was bonded to obtain a surface of a semiconductor wafer having a thickness of 130 μm. Adhesive tape for protection.

[Characteristic evaluation test]

With respect to the adhesive tape for semiconductor wafer surface protection of the above-described examples and comparative examples, the property evaluation test was performed as follows. The results are shown in Tables 1 and 2.

(1) Peel force

The peeling force at a peeling angle of 30° was measured using the adhesive tape for semiconductor wafer surface protection produced in each of the examples and the comparative examples.

A test piece 14 having a width of 25 mm and a length of 300 mm was cut out from the adhesive tape for semiconductor wafer surface protection (see Fig. 10). The above-mentioned test piece 14 was rubbed back and forth with a rubber roller of 2 kg in a stainless steel (Steel Use Stainless, SUS) plate having a thickness of 1.5 mm as defined in JIS G 4305, which was treated with a water-resistant abrasive paper No. 280 according to JIS R 6253. Pressed 3 times. After standing for one hour, the back surface of the base resin film of the adhesive surface of the semiconductor wafer surface protection adhesive was irradiated with ultraviolet rays of 500 mJ/cm ² (illuminance: 40 mW/cm ² ), and further allowed to stand for one hour, and then the measurement value was used. The peeling force was measured by a tensile tester (double-column table type 5567) manufactured by Instron Co., Ltd. of JIS B 7721 in the range of 15 to 85% of the capacity. Specifically, the SUS plate is fixed to the susceptor 15 inclined at 30° as shown in Fig. 10, and the end portion of the test piece 14 is held by the jig 16 at a tensile speed of 20 mm/min, 25 ° C, and relative. The measurement was carried out by stretching under the conditions of a humidity of 50%. Each of the semiconductor wafer surface protective adhesive tapes was subjected to three times, and the arithmetic mean value thereof was determined and used as a 30° peeling force. The susceptor 15 that fixes the SUS plate is adjusted to be driven to be peeled off, and the peeling angle θ is usually set to 30°. In the case where the susceptor 15 is not driven, the measurement may be started at an acute angle smaller than 30°, and the peeling force at a point at which the peeling angle θ becomes 30° may be read. Further, the SUS plate was fixed to a pedestal without inclination, and peeled off at a peeling speed of 50 mm/min by a 90° stretching and peeling method, and 90° peeling at a peeling angle of 90° was obtained in the same manner as described above. force. When the pressure-sensitive adhesive was a pressure-sensitive type, it was placed in the same manner as in the state where the SUS plate was heated to 50° C., and the 30° peeling force was measured in the same manner as in the case of irradiation with ultraviolet rays and irradiation for 1 hour.

(2) Repulsive force (ring stiffness)

The repulsive force α was measured using LOOP STIFFNESS TESTER (trade name) manufactured by Toyo Seiki Co., Ltd. The semiconductor wafer surface protective adhesive tape produced in each of the examples and the comparative examples was cut into a width of 10 mm to prepare a test piece, and the spacer was placed in a state of LOOP STIFFNESS TESTER. At this time, a circular ring having a ring length of 50 mm was produced in the vicinity of the center of the strip-shaped test piece having a ring length of 50 mm or more so that the adhesive layer was inside, and the measurement was performed when the circular ring was pressed 5 mm from the outside. The applied load. The load obtained at this time is converted into a load per unit width, and the value expressed in units of mN/mm is taken as the repulsive force α . For the semiconductor wafer surface protection adhesive tape produced in each of the examples and the comparative examples, the evaluation of the three samples was carried out, and the value after arithmetic averaging was used.

(3) Gel fraction of the slurry

The semiconductor wafer surface protective adhesive tape produced in each of the examples and the comparative examples was cut into 50 mm × 50 mm. The spacer was peeled off from the cut sample, and the weight (weight before immersion) was measured. The base resin film to which the adhesive was not applied was also cut into 50 mm × 50 mm in the same manner, and the weight (base weight) was measured. After the weight measurement, the cut sample was immersed in a 500 ml polypropylene container filled with a CMP slurry, and after standing for 24 hours, the sample was taken out from the container, and the slurry was thoroughly rinsed with pure water. The CMP slurry system was at pH 12 In the aqueous sodium hydroxide solution, 14% by weight of colloidal cerium oxide having an average particle diameter of 50 nm was dispersed. After standing for 3 days for drying, the sample weight (weight after drying) was measured. The gel fraction is determined by the following calculation formula.

Gel fraction = (weight after drying - weight of substrate) / (weight before impregnation - weight of substrate) × 100 (%)

In addition, the weight of the substrate can also be calculated from the density x volume by calculation instead of the actual test.

(4) Evaluation of the grinding method after cutting

[cutoff offset]

As shown in Fig. 9, a semiconductor wafer having a thickness of 725 μm and a diameter of 725 μm is used to form a circuit pattern of a semiconductor wafer and a dummy step of a groove provided at a predetermined cutting portion. Specifically, for the sake of forgery A step of the circuit pattern was formed, and a line having a width of 60 μm and a depth of 10 μm was formed in a lattice shape at intervals of 5 mm. Further, as a groove provided at a predetermined cutting portion, a groove having a width of 30 and a depth of 60 μm is further provided in the center of the line width.

The DR8500II (trade name) manufactured by Nitto Seiki Co., Ltd., which is a bonding machine, is bonded to the surface of the semiconductor wafer on which the dummy step is formed so that the surface protection tape MD direction coincides with the semiconductor wafer slit direction. Adhesive tape for semiconductor wafer surface protection of each of the examples and the comparative examples. Then, using PG3000RM (trade name) manufactured by Tokyo Seimi Co., Ltd. as a grinder, the back surface of the semiconductor wafer was ground until the thickness of the semiconductor wafer was 30 μm, and polishing was performed using a CMP slurry to make a pattern-like difference crystal. The circle was made small.

For the semiconductor wafer after the back grinding, as shown in FIG. 9, the kerf width (ditch) at three points in the center portion and the peripheral portion of the semiconductor wafer was observed by an optical microscope, and the kerf width was measured. The observation of the kerf width is performed within one hour after the semiconductor wafer is ground, and the surface protection tape is bonded to the back side of the semiconductor wafer from which the surface protection tape is not attached. For the kerf offset, the kerf width of the wafer after grinding was measured by an optical microscope, and the absolute value of the variation from the kerf width (30 μm) before the grinding was measured in the X direction and the Y direction. The average value Kx of the X direction at 3 points and the average value Ky of the Y direction were evaluated. The case where the average value of Kx and Ky is less than 5 μm and 0.8 ≦ (Ky/Kx) ≦ 1.1 is ○, and the average value of Kx and Ky is 5 μm or more or Ky/Kx < 0.8 or 1.1 < Ky / The case of Kx is × as a defective product.

[wafer peeling]

After observing the kerf width, ultraviolet rays of 500 mJ/cm ² were irradiated from the base film side of the adhesive tape for semiconductor wafer surface protection. Then, the adhesive grain film is bonded to the polished surface of the semiconductor wafer. Thereafter, the surface of the adhesive tape for semiconductor wafer surface protection is then heat-sealed to peel off the adhesive tape for surface protection of the semiconductor wafer. By visually confirming the presence or absence of wafer peeling, the wafer peeling was observed as a good product, and the non-square wafer at the end was peeled off. However, the inner square wafer was not peeled off as a good product. A part or all of the peeling of the wafer is × as a defective product.

[sticky residue]

Further, the surface of the dummy wafer in which the semiconductor wafer surface protective adhesive tape was peeled off was observed by an optical microscope. In the case of the defective surface of the semiconductor wafer, the residue of the adhesive for the adhesive tape for the surface protection of the semiconductor wafer cannot be confirmed as a good product, and even if there is a residue in one portion, it is × as a defective product. Further, in Comparative Example 3, since a large amount of dust intrusion was observed, the determination of the adhesive residue could not be performed.

[dust intrusion]

Moreover, the wafer of the semiconductor wafer surface protection adhesive tape after the semiconductor wafer surface protection adhesive tape is peeled off by the optical microscope and the semiconductor wafer surface protection adhesive tape after the semiconductor wafer surface protection adhesive tape is peeled off In the bonding surface, no dust was observed in the dummy surface and the wafer bonding surface, and the discoloration corresponding to the portion of the kerf when the bonding of the wafer bonding surface was not observed was ◎, although it was observed The discoloration corresponding to the portion of the kerf when the wafer bonding surface is bonded, but the falsified step surface and the wafer bonding surface are not confirmed to have a dust as a good product, and ○ will be used for the counterfeit section or the wafer paste. It is confirmed that the dust is a defective product and is ×.

(5) Assessment of general grinding

[Wafer Warping]

The adhesive tape for semiconductor wafer surface protection of each of the examples and the comparative examples was bonded to a thickness of 780 μm coated with 5 μm of polyimide, using DR8500II (trade name) manufactured by Nitto Seiki Co., Ltd. as a bonding machine. The 8 inch wafer was ground using a DGP 8760 (trade name) manufactured by DISCO, Inc. as a grinder until the wafer thickness was 50 μm. For the semiconductor wafer surface protection adhesive tape, four wafers are ground, and one of the transport errors due to warpage of the wafer during the transfer process in the polishing machine is not good. The transport error due to the warpage of the wafer is × as a defective product even if only one sheet is generated.

As shown in Table 1, in the case where the base resin film has a rigid layer and the peeling force at a peeling angle of 30° is 0.1 to 3.0 N/25 mm, the semiconductors can be contaminated or damaged without causing semiconductor wafer contamination or damage. The wafer is processed. On the other hand, as shown in Table 2, the nips of Comparative Examples 2 and 3 having no rigid layer were largely offset, and cracking of the wafer due to the contact of the diced wafer was also observed. Further, in Comparative Example 1 in which the peeling angle was 30° or more and more than 3.0 N/25 mm, wafer peeling and adhesive residue occurred.

As described in the examples and the comparative examples, the adhesive tape for surface protection of a semiconductor wafer of the present invention exhibits an effect of reducing the amount of kerf offset and preventing the wafer from being contaminated or damaged.

1‧‧‧Adhesive tape for semiconductor wafer surface protection

2‧‧‧Substrate resin film

Claims (10)

An adhesive tape for protecting a surface of a semiconductor wafer, comprising: a base resin film; and a radiation-curable adhesive layer formed on at least one side of the base resin film, wherein the base resin film has at least A rigid layer having a tensile modulus of 1 to 10 GPa, which is subjected to radiation hardening of the adhesive layer, and the adhesive layer is treated according to JIS G with respect to the water-resistant abrasive paper No. 280 according to JIS R 6253. The peeling force of stainless steel (Steel Use Stainless, SUS) specified in 4305 at a peeling angle of 30° is 0.1 to 3.0 N/25 mm. An adhesive tape for protecting a surface of a semiconductor wafer, comprising: a base resin film; and an adhesive layer formed on at least one side of the base resin film and not hardened by irradiation of radiation, the base The resin film has at least one rigid layer having a tensile modulus of 1 to 10 GPa, and is treated at 50 ° C with respect to JIS G 4305 which is treated with a water-resistant abrasive paper of No. 280 according to JIS R 6253. The peeling force of stainless steel (Steel Use Stainless, SUS) having a thickness of 1.5 mm at a peeling angle of 30° was 0.1 to 3.0 N/25 mm. The adhesive tape for protecting a surface of a semiconductor wafer according to claim 1 or 2, wherein a repulsive force per unit width obtained by a load load of a loop stiffness measured under the following conditions (a) to (d) is 2~15mN/mm, (a) device LOOP STIFFNESS TESTER (trade name, manufactured by Toyo Seiki Seisakusho Co., Ltd.) (b) Ring (test piece) has a shape length of 50 mm and a width of 10 mm, and the direction of the test piece is in the MD direction (c) The indentation speed of the indenter is 3.3 mm/sec. (d) The amount of pressing of the indenter is pressed 5 mm from the point of contact of the indenter with the ring. The adhesive tape for protecting a semiconductor wafer surface according to claim 1 or 2, wherein the layer between the rigid layer and the adhesive layer is composed only of a layer having a tensile modulus of less than 1 GPa, the adhesive layer The total thickness and the thickness of the layer having a tensile modulus of less than 1 GPa are 60 μm or less. The adhesive tape for protecting a semiconductor wafer surface according to claim 1 or 2, wherein the adhesive layer is immersed in the slurry for chemical mechanical polishing for 24 hours, and the ratio of the insoluble fraction after immersing in the slurry is 75. More than %, the slurry system for chemical mechanical polishing has 14% by weight of colloidal cerium oxide having an average particle diameter of 50 nm dispersed in an aqueous sodium hydroxide solution of pH 12. The adhesive tape for protecting a semiconductor wafer surface according to claim 1, wherein the adhesive layer contains a radioactive resin having an ethylenically unsaturated group in a side chain, and includes a reaction with the radioactive agent by irradiation of radiation. A modifier which reacts to reduce the peeling force. An adhesive tape for protecting a surface of a semiconductor wafer according to claim 6 In the above, the modifier is a non-fluorenone system. A method of manufacturing a semiconductor wafer, comprising the steps of: (a) forming a trench for forming a predetermined line of a semiconductor wafer from a surface of the semiconductor wafer that does not reach a thickness of the semiconductor wafer; (b) a step of bonding the semiconductor wafer surface protective adhesive tape according to any one of claims 1 to 7 to the surface of the semiconductor wafer on which the groove is formed, and (c) by using the semiconductor wafer back surface The step of dicing the semiconductor wafer by grinding. A method of manufacturing a semiconductor wafer, comprising the steps of: (a) forming a modified region by irradiating a laser inside the semiconductor wafer of a predetermined line of semiconductor wafer cutting, (b) And a step of bonding the semiconductor wafer surface protective adhesive tape according to any one of claims 1 to 7 to the surface of the semiconductor wafer before or after the step (a), and (c) by using the foregoing semiconductor crystal The step of grinding the back surface of the semiconductor wafer by grinding the back surface. The method of manufacturing a semiconductor wafer according to claim 8, wherein the step (c) comprises the step of performing chemical polishing.