JP2018152529A - Dicing adhesive tape, dicing adhesive tape manufacturing method, and semiconductor chip manufacturing method - Google Patents

Abstract

A dicing pressure-sensitive adhesive tape and the like that can easily peel off a semiconductor chip even when attached to an active surface of a semiconductor element substrate. An adhesive tape for dicing has a base material and an adhesive layer provided on at least one surface side of the base material. The adhesive layer has at least a hydroxyl group as a functional group, An acrylate-based copolymer having any one of carboxyl groups, and having a weight average molecular weight Mw of 500 or more and 6000 or less and having three or more radiation-polymerizable carbon-carbon double bonds in the molecule. A radiation-curable oligomer having a hydroxyl value of 3 mgKOH / g or less and a crosslinking agent that reacts with a functional group of the acrylate-based copolymer are provided. [Selection diagram] Fig. 1

Description

  The present invention relates to a dicing adhesive tape used for dicing an element substrate, a method for manufacturing a dicing adhesive tape, and a method for manufacturing a semiconductor chip.

A semiconductor-related material such as a semiconductor package or a semiconductor element substrate such as a semiconductor wafer is cut using, for example, a rotary blade and separated into small semiconductor elements and IC components.
For example, a semiconductor wafer made of silicon, germanium, gallium-arsenide, or the like is manufactured in a large diameter state, and then the back surface is ground (back grind processing) until a predetermined thickness is obtained. Accordingly, back surface processing (etching processing, polishing processing, etc.) is performed.
Subsequently, a mounting step of attaching a dicing adhesive tape to the ground surface of the semiconductor wafer, a dicing step of dicing the semiconductor wafer into individual semiconductor chips with the adhesive tape attached to the semiconductor wafer, and a cleaning step of cleaning the semiconductor wafer In order to facilitate the subsequent pickup of the semiconductor chip, an expanding process for stretching the adhesive tape, a pickup process for peeling the semiconductor chip from the adhesive tape, and the like are performed.
In the pick-up step, the dicing adhesive tape is stretched to some extent, and the semiconductor chip is mounted from the side where the substrate is located with respect to the dicing adhesive tape using one or a plurality of push-up pins (needles). A system is adopted in which the semiconductor chip is picked up by vacuum suction or the like using a collet in the state where the semiconductor chip and the dicing adhesive tape are peeled and lifted.

Conventionally, a pressure-sensitive adhesive tape having a radiation-curable pressure-sensitive adhesive layer is known as a pressure-sensitive adhesive tape for dicing used for producing a semiconductor chip. For example, a pressure-sensitive adhesive tape including a radiation-curable pressure-sensitive adhesive layer having a (meth) acrylic polymer having a linear alkyl group having 14 to 18 carbon atoms is known (see Patent Document 1).
Moreover, the adhesive tape containing the radiation-curable adhesive layer which has an acrylic polymer whose hydroxyl value is 15-60 mgKOH / g is known as an adhesive tape for dicing (refer patent document 2).

JP 2010-232629 A JP 2012-216842 A

By the way, in recent years, in the semiconductor manufacturing process, for the purpose of improving the production efficiency of semiconductor chips and preventing damage due to thinning of the semiconductor wafer (for example, 100 μm or less), After the grinding and the back surface treatment, a dicing adhesive tape may be applied to the ground surface of the semiconductor wafer in a short time.
That is, in order to improve the productivity of a semiconductor chip manufactured by cutting a semiconductor wafer, the semiconductor wafer is diced immediately in-line immediately after the back grinding process in the manufacturing process of the semiconductor chip. is there. In this case, after the back surface of the semiconductor wafer is ground to thin the semiconductor wafer, a dicing adhesive tape is attached to the ground surface of the semiconductor wafer in a short period of time.

  Further, with the thinning of the semiconductor wafer described above, the semiconductor wafer is easily warped by its own weight, and there is a problem that the semiconductor wafer is easily damaged when handled or stored in a transfer case. From the viewpoint of improving this problem and improving workability, an increasing number of cases adopt an in-line dicing method immediately after grinding the back surface of the semiconductor wafer. Since the dicing adhesive tape affixed to the grinding surface of the semiconductor wafer has the function of a semiconductor wafer support, the semiconductor wafer to which the dicing adhesive tape is affixed is not stored in the transport case, Dicing inline. Thereby, damage to the above-described thinned semiconductor wafer can be suppressed.

  As described above, the adhesive tape is often attached to the ground surface immediately after grinding the semiconductor wafer. However, the conventional dicing adhesive tape has the following problems. That is, the surface immediately after grinding of a semiconductor element substrate such as a semiconductor wafer is an active surface on which active atoms are present. When a conventional dicing adhesive tape is attached to this active surface, the surface of the substrate for semiconductor element adhesion The adhesive strength of the tape becomes excessively large, and as a result, there is a problem that even if the adhesive tape is irradiated with radiation to cure the adhesive layer, it is difficult to peel off the semiconductor chip from the adhesive tape.

  An object of this invention is to provide the adhesive tape for dicing which is easy to peel off the obtained semiconductor chip, even when it affixes with respect to the active surface of the board | substrate for semiconductor elements.

  As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, radiation curability having a weight average molecular weight and a hydroxyl value within a specific range and having at least three radiation-polymerizable carbon-carbon double bonds. If an adhesive tape comprising an adhesive layer containing an oligomer and an acrylic acid ester copolymer as a main component is used, an excess between the adhesive layer and the active surface of the semiconductor element substrate surface immediately after grinding It has been found that individual semiconductor chips formed by dicing are easily peeled off from the pressure-sensitive adhesive layer in combination with effective curing and shrinkage of the pressure-sensitive adhesive layer by irradiation of the pressure-sensitive adhesive tape. It came to make.

  That is, the pressure-sensitive adhesive tape for dicing of the present invention has a base material and a pressure-sensitive adhesive layer provided on at least one surface side of the base material, and the pressure-sensitive adhesive layer has at least a hydroxyl group or a carboxyl group as a functional group. An acrylic ester copolymer having any one of the above, a crosslinking agent that reacts with the functional group of the acrylic ester copolymer, and a weight average molecular weight Mw of 500 to 6000, A radiation curable oligomer having three or more radiation-polymerizable carbon-carbon double bonds in the molecule and a hydroxyl value of 3 mgKOH / g or less.

Here, the pressure-sensitive adhesive layer preferably has a storage elastic modulus of 1.0 × 10 ⁶ Pa or more and 7.0 × 10 ⁸ Pa or less after being cured by irradiation with radiation.
The pressure-sensitive adhesive layer preferably contains 80 parts by mass or more and 180 parts by mass or less of the radiation curable oligomer when the acrylic ester copolymer is 100 parts by mass.

  Moreover, the manufacturing method of the pressure-sensitive adhesive tape for dicing according to the present invention is a base material preparation step for preparing a base material and a coating solution for forming a pressure-sensitive adhesive layer, and at least any one of a hydroxyl group and a carboxyl group as a functional group An acrylic ester copolymer having one of them, a crosslinking agent that reacts with the functional group of the acrylic ester copolymer, and a weight average molecular weight Mw of 500 to 6000, and radiation in the molecule. A coating solution preparation step of preparing a coating solution containing a radiation curable oligomer having three or more polymerizable carbon-carbon double bonds and a hydroxyl value of 3 mgKOH / g or less, and using the coating solution, A pressure-sensitive adhesive layer forming step for forming the pressure-sensitive adhesive layer on at least one surface side of the substrate, and a treatment for cross-linking the acrylic ester copolymer and the cross-linking agent. , The formed pressure-sensitive adhesive layer, characterized in that it comprises a thermal curing step for thermally curing the.

  Further, in the method for manufacturing a semiconductor chip of the present invention, the dicing adhesive tape is attached to an element substrate having a plurality of semiconductor elements formed on the substrate, and the dicing adhesive tape is attached. A cutting step of cutting the element substrate into a plurality of semiconductor chips, and irradiating the dicing adhesive tape attached to the semiconductor chips with radiation to reduce the adhesive strength of the dicing adhesive tape An irradiation step, and a peeling step of peeling off the semiconductor chip from the dicing pressure-sensitive adhesive tape having reduced adhesive strength, the dicing pressure-sensitive adhesive tape on the surface side of at least one of the base material and the base material Provided, and the pressure-sensitive adhesive layer has at least one of a hydroxyl group and a carboxyl group as a functional group. A crylate ester copolymer, a crosslinking agent that reacts with the functional group of the acrylate ester copolymer, a weight average molecular weight Mw of 500 to 6000, and a radiation-polymerizable carbon-carbon in the molecule And a radiation curable oligomer having three or more double bonds and a hydroxyl value of 3 mgKOH / g or less.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where it affixes with respect to the active surface of the board | substrate for semiconductor elements, the adhesive tape for dicing etc. which can peel off a semiconductor chip easily can be provided.

It is the figure which showed an example of the structure of the adhesive tape to which this Embodiment is applied. It is the flowchart explaining the manufacturing method of the adhesive tape. It is the flowchart explaining the manufacturing method of the semiconductor chip. (A)-(d) is the figure which showed the manufacture example of the semiconductor chip which used the adhesive tape. It is the figure shown about the Example and the comparative example.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not limited to the following embodiment. Various modifications can be made within the scope of the gist. Further, the drawings to be used are for explaining the present embodiment and do not represent the actual size.

<Configuration of adhesive tape>
FIG. 1 is a diagram illustrating an example of a configuration of an adhesive tape 1 to which the exemplary embodiment is applied. The pressure-sensitive adhesive tape 1 of the present embodiment is used for dicing a semiconductor wafer as an example of an element substrate.

As shown in FIG. 1, the adhesive tape 1 of this Embodiment has the structure where the base material 2 and the adhesive layer 3 were laminated | stacked.
In addition, although illustration is abbreviate | omitted, the adhesive tape 1 may be provided with the anchor coat layer between the base material 2 and the adhesive layer 3 as needed. Further, a release liner may be provided on the surface side (one surface side) opposite to the base material 2 of the pressure-sensitive adhesive layer 3.

<Base material>
The base material 2 serves as a support for the pressure-sensitive adhesive layer 3. Moreover, the base material 2 is calculated | required to have a radiation transmittance.
As a material used for such a base material 2, plastic, metal, paper, or the like can be used. However, in the present embodiment, from the viewpoint of easy transmission of radioactivity, A thing can be used conveniently. Examples of the material for the plastic substrate 2 include polyolefin resins (low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolymer). Polypropylene, polybutene, polymethylpentene, etc.), ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester copolymer (random copolymer, Alternating copolymers), ethylene-butene copolymers, ethylene-hexene copolymers, polyurethane resins, polyester resins (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, etc.) Polyimide resin, polyamide resin, polyether ketone resin, polyether resin, polyether sulfone resin, polystyrene resin (polystyrene, etc.), polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, A polyvinyl acetate resin, a vinyl chloride-vinyl acetate copolymer, a polycarbonate resin, a fluorine resin, a silicone resin, a cellulose resin, a cross-linked product of these resins, and the like can be used. These may be used alone or in combination of two or more. These materials may have a functional group. In addition, a functional monomer or a modifying monomer may be grafted to these materials. Furthermore, in order to improve the adhesion between the surface of the substrate 2 and the layer adjacent to the substrate 2, a surface treatment may be performed on the surface of the substrate 2. Examples of such surface treatment include corona discharge treatment, ozone exposure treatment, high piezoelectric impact exposure treatment, and ionizing radiation treatment. Further, the base material 2 may be subjected to coating treatment with a primer, primer treatment, mat treatment, crosslinking treatment, and the like.

  As the base material 2, any of a single layer structure and a laminated structure can be used. In addition, the base material 2 contains additives such as a filler, a flame retardant, an anti-aging agent, an antistatic agent, a softening agent, an ultraviolet absorber, an antioxidant, a plasticizer, and a surfactant as necessary. It may be. Although the thickness of a base material is not specifically limited, 10-300 micrometers is preferable and 30-200 micrometers is more preferable.

<Adhesive layer>
The pressure-sensitive adhesive layer 3 is a functional layer having adhesiveness and exhibiting adhesive force between the pressure-sensitive adhesive tape 1 and the adherend. In addition, the pressure-sensitive adhesive layer 3 of the present embodiment has a property that when it is irradiated with radiation, it is cured and contracted to reduce the adhesive force.
Thereby, when the adhesive tape 1 is used for dicing of a semiconductor wafer, the adhesive tape 1 has good adhesiveness to the semiconductor wafer. Further, when a semiconductor wafer is cut at regular intervals by dicing, individual semiconductor chips are formed. However, by irradiating the adhesive tape 1 with radiation, the semiconductor chips can be easily peeled off from the adhesive tape 1. Examples of radiation include X-rays, electron beams, and ultraviolet rays. Especially, in this Embodiment, an ultraviolet-ray can be used more suitably.

  The pressure-sensitive adhesive layer 3 of the present embodiment includes an acrylate copolymer as a pressure-sensitive adhesive and a radiation curable oligomer. Moreover, the adhesive layer 3 contains the crosslinking agent which reacts with the functional group which an acrylate ester-type copolymer has, and a photoinitiator. Moreover, the adhesive layer 3 may contain a coloring agent etc. as needed.

The pressure-sensitive adhesive layer 3 preferably has a storage elastic modulus of 1.0 × 10 ⁶ Pa to 7.0 × 10 ⁸ Pa after irradiation and curing.
When the storage elastic modulus is less than 1.0 × 10 ⁶ Pa, even if the adhesive tape 1 is irradiated with radiation, the adhesive force is hardly reduced. As a result, it becomes difficult to peel off individual semiconductor chips formed by dicing from the adhesive tape 1.
If the storage elastic modulus is larger than 7.0 × 10 ⁸ Pa, the pressure-sensitive adhesive layer 3 becomes hard and the bending elastic modulus becomes too high. Therefore, the semiconductor chip is pushed up through the adhesive tape 1 to adhere the semiconductor chip. When the semiconductor chip is thin when it is peeled off from the tape 1, there is a risk of cracking.

The thickness of the pressure-sensitive adhesive layer 3 is preferably in the range of 3 μm to 50 μm, and more preferably in the range of 5 μm to 20 μm.
When the thickness of the adhesive layer 3 is less than 3 μm, the adhesive strength of the adhesive tape 1 may be excessively reduced. In this case, when the semiconductor wafer is diced, the adhesive tape 1 cannot sufficiently hold the semiconductor chip, and the semiconductor chip may be scattered.
On the other hand, when the thickness of the pressure-sensitive adhesive layer 3 is thicker than 50 μm, vibration during dicing is easily transmitted to the pressure-sensitive adhesive layer 3 and the vibration width becomes large, and this semiconductor wafer becomes a reference during dicing of the semiconductor wafer. There is a risk of displacement. In this case, there is a possibility that chipping (chipping) occurs in the semiconductor chip, or that the size of each semiconductor chip shifts.

(Acrylate ester copolymer)
The acrylic ester copolymer is not particularly limited, but is, for example, a pressure-sensitive adhesive mainly composed of a (meth) acrylic polymer. The (meth) acrylic polymer is, for example, a copolymer of a linear and / or branched alkyl group-containing (meth) acrylic monomer, a (meth) acrylic monomer having a functional group, and other monomers as necessary. Can be obtained.
As the acrylic ester copolymer, a copolymer having any one of a hydroxyl group and a carboxyl group as a functional group can be suitably used.

  Examples of linear or branched alkyl group-containing (meth) acrylic monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acrylic Butyl acid, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, ( Octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, Undecyl (meth) acrylate, dodecyl (meth) acrylate, (meth) acrylic Tridecyl, tetradecyl (meth) acrylate, (meth) acrylate, myristyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl include (meth) octadecyl acrylate. These may be used alone or in combination of two or more. Among these, in the present embodiment, a (meth) acrylic monomer containing an alkyl group having 4 or more and 12 or less carbon atoms can be suitably used, and an alkyl group having 8 carbon atoms is contained ( More preferred is 2-ethylhexyl (meth) acrylate.

  Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6- (meth) acrylic acid 6-. Hydroxyhexyl etc. are mentioned. These may be used alone or in combination of two or more.

  Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, itaconic acid, cinnamic acid, fumaric acid, and phthalic acid. These may be used alone or in combination of two or more.

  In the present embodiment, the acrylate copolymer may contain other copolymerization monomer components as necessary as long as the effects of the present invention are not hindered. Specific examples of such other copolymerization monomer components include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, (meth) acrylamide, and N, N-dimethyl (meth) acrylamide. Amide monomers such as aminoethyl (meth) acrylate, amino group-containing monomers such as N, N-dimethylaminoethyl (meth) acrylate, cyano group-containing monomers such as (meth) acrylonitrile, ethylene, propylene Olefin monomers such as isoprene and butadiene, styrene monomers such as styrene, α-methylstyrene and vinyltoluene, vinyl ester monomers such as vinyl acetate and vinyl propionate, and vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether Monomer, vinyl chloride, vinyl chloride Halogen atom-containing monomers such as ethylene, alkoxy group-containing monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, and nitrogen atoms such as N-vinyl-2-pyrrolidone and N-methylvinylpyrrolidone And monomers having a ring.

  Moreover, in this Embodiment, what introduce | transduced the radiation-polymerizable carbon-carbon double bond into the side chain can also be used for an acrylate-type copolymer. For example, an acrylic ester copolymer having a hydroxyl group is synthesized, and then the hydroxyl group of the synthesized acrylic ester copolymer is reacted with 2-methacryloyloxyethyl isocyanate to form a radiation-polymerizable carbon-carbon in the side chain. Examples include acrylate copolymer having a methacryloyl group acting as a double bond.

(Radiation curable oligomer)
The radiation curable oligomer has a property of curing when irradiated with radiation. The radiation curable oligomer is not particularly limited, and an epoxy acrylate oligomer, a urethane acrylate oligomer, a polyester acrylate oligomer, or the like can be used. Epoxy acrylate is synthesized by an addition reaction between an epoxy compound and a carboxylic acid. The urethane acrylate is synthesized, for example, by reacting an isocyanate reaction remaining at the terminal with an hydroxy group-containing acrylate in an addition reaction product of a polyol and a polyisocyanate and introducing an acrylic group into the molecular terminal. Polyester acrylate is synthesized by reaction of polyester polyol and acrylic acid.

In the present embodiment, urethane acrylate oligomers can be suitably used. The adhesive force of the pressure-sensitive adhesive layer 3 is reduced by the curing of the radiation-curable oligomer.
The pressure-sensitive adhesive layer 3 preferably contains 80 parts by mass or more and 180 parts by mass or less of a radiation curable oligomer when the acrylic ester copolymer is 100 parts by mass.

When the content of the radiation curable oligomer is less than 80 parts by mass, even if the adhesive tape 1 is irradiated with radiation, the adhesive layer 3 is not sufficiently cured and contracted, and the adhesive force is not easily lowered. As a result, it becomes difficult to peel off individual semiconductor chips formed by dicing of the semiconductor wafer from the adhesive tape 1, and part of the semiconductor chips may be lost during the peeling.
Moreover, when the content of the radiation curable oligomer exceeds 180 parts by mass, when the adhesive tape 1 is irradiated with radiation, the pressure-sensitive adhesive layer 3 becomes hard due to the increased amount of the cured oligomer, and the flexural modulus is increased. Since it becomes too high, when the semiconductor chip is pushed up through the adhesive tape 1 and peeled off from the adhesive tape 1, if the semiconductor chip is thin, it may break.

In the present embodiment, it is preferable to use a radiation curable oligomer having a hydroxyl value of 3 mgKOH / g or less. Here, the hydroxyl value is the amount (mg) of potassium hydroxide required to acetylate the OH group contained in 1 g of the object.
Here, when the hydroxyl value of the radiation curable oligomer is larger than 3 mgKOH / g, particularly when the adhesive tape 1 is applied to a semiconductor wafer immediately after grinding, the adhesive force of the adhesive layer 3 to the semiconductor wafer becomes excessively large. . As a result, even if the adhesive tape 1 is irradiated with radiation, individual semiconductor chips formed by dicing may be difficult to peel off from the adhesive tape 1 or the semiconductor chips may be lost.

That is, when a semiconductor wafer is thinned by grinding in the process of manufacturing a semiconductor chip, a natural oxide film is formed over time on the surface of the semiconductor wafer. Here, in order to improve the productivity of the semiconductor chip, when the step of attaching the adhesive tape 1 to the ground surface immediately after the semiconductor wafer is ground and thinned, the surface of the ground semiconductor wafer is in an unoxidized state. In addition, the active surface has active atoms (for example, silicon atoms). When the active atom on the active surface and the hydroxyl group of the radiation curable oligomer are bonded, the adhesive force of the pressure-sensitive adhesive layer 3 becomes excessively large.
As a result, even after irradiation, it becomes difficult to peel off individual semiconductor chips formed by dicing from the adhesive tape 1, and in this case, there is a possibility that some of the semiconductor chips are lost.

  On the other hand, when a radiation curable oligomer having a hydroxyl value of 3 mgKOH / g or less is used, the number of hydroxyl groups bonded to the active atoms on the active surface of the semiconductor wafer (the hydroxyl group of the radiation curable oligomer) is small. It is suppressed that the adhesive force of the adhesive layer 3 becomes too large. As a result, the semiconductor chip can be easily peeled off from the adhesive tape 1. The hydroxyl value of the radiation curable oligomer is preferably 0 mgKOH / g.

Moreover, as a radiation-curable oligomer, it is preferable to use what has three or more radiation-polymerizable carbon-carbon double bonds in a molecule | numerator.
When the radiation-curable oligomer does not have three or more radiation-polymerizable carbon-carbon double bonds in the molecule, the pressure-sensitive adhesive layer 3 is sufficiently cured and contracted even when the pressure-sensitive adhesive tape 1 is irradiated with radiation. Therefore, the adhesive strength is difficult to decrease. As a result, it becomes difficult to peel off individual semiconductor chips formed by dicing from the adhesive tape 1.
In addition, when using a radiation-curable oligomer having three or more radiation-polymerizable carbon-carbon double bonds in the molecule, in addition to this, unless the effect of the present invention is hindered, the radiation-polymerizable property in the molecule. A radiation curable oligomer having two carbon-carbon double bonds may be used in combination. Also in this case, it is preferable to use a radiation curable oligomer having a hydroxyl value of 3 mgKOH / g or less.

Moreover, it is preferable to use a radiation curable oligomer having a weight average molecular weight Mw of 500 or more and 6000 or less.
When a radiation curable oligomer having a weight average molecular weight Mw of less than 500 is used, the pressure-sensitive adhesive layer 3 becomes hard due to the effect of increasing the crosslinking density between the oligomers when the pressure-sensitive adhesive tape 1 is irradiated with radiation. Since the elastic modulus becomes high, when the semiconductor chip is pushed up through the adhesive tape 1 and peeled off from the adhesive tape 1, the semiconductor chip may be cracked.

  Moreover, when using the radiation curable oligomer whose weight average molecular weight Mw is larger than 6000, when the adhesive tape 1 is irradiated with radiation, the degree of curing and shrinkage of the adhesive layer 3 is small. Adhesive strength is less likely to decrease. As a result, it becomes difficult to peel off individual semiconductor chips formed by dicing the semiconductor wafer from the adhesive tape 1.

(Crosslinking agent)
As a crosslinking agent, what reacts with the functional group which an acrylate ester-type copolymer has can be used conveniently. When the functional group of the acrylic ester copolymer is a hydroxyl group, an isocyanate crosslinking agent can be suitably used, and when the functional group of the acrylic ester copolymer is a carboxyl group, an epoxy crosslinking agent can be suitably used.
The addition amount of the crosslinking agent is such that the total amount of functional groups that react with the functional groups of the acrylate copolymer in the crosslinking agent is 1 mol with respect to the functional groups of the acrylate copolymer. An amount that is equal to or greater than the equivalent is preferred.

(Photopolymerization initiator)
The photopolymerization initiator has a role of generating radicals when the adhesive tape 1 is irradiated with radiation and cleaving the radiation carbon-carbon double bond to initiate a polymerization reaction.
Examples of the photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzophenone, benzoyl benzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, α-hydroxycyclohexyl phenyl ketone, 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, methoxyacetophenone, 2,2-dimethoxy-2- Phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane-1, benzyldimethyl ketal, thioxa N, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2-dodecylthioxanthone, 2,4-dichlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2, Examples include 4-diisopropylthioxanthone, benzyl, benzoin, 2-methyl-2-hydroxypropiophenone, 2-naphthalenesulfonyl chloride, 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime, and the like. . These may be used alone or in combination of two or more.

<Anchor coat layer>
As described above, in the pressure-sensitive adhesive tape 1 according to the present embodiment, a base material 2 and a pressure-sensitive adhesive layer 3 are provided between the base material 2 and the pressure-sensitive adhesive layer 3 in accordance with the manufacturing conditions of the pressure-sensitive adhesive tape 1 and the usage conditions of the pressure-sensitive adhesive tape 1 after manufacturing. You may provide the anchor coat layer according to the kind of material. By providing the anchor coat layer, the adhesion between the substrate 2 and the pressure-sensitive adhesive layer 3 is improved.

<Release liner>
Moreover, you may provide a peeling liner as needed in the surface side (one surface side) opposite to the base material 2 of the adhesive layer 3. FIG. What can be used as a release liner is not particularly limited, and examples thereof include synthetic resins such as polyethylene, polypropylene, and polyethylene terephthalate, and papers. Moreover, in order to improve the peelability of the pressure-sensitive adhesive layer 3, the surface of the release liner may be subjected to a release treatment with a silicone release treatment agent, a long-chain alkyl release treatment agent, a fluorine release treatment agent, or the like. Although the thickness of a release liner is not specifically limited, A thing of 10 micrometers or more and 200 micrometers or less can be used conveniently.

<Manufacturing method of adhesive tape>
FIG. 2 is a flowchart illustrating a method for manufacturing the adhesive tape 1.
First, the base material 2 is prepared (step 101: base material preparation process).
Next, a coating solution for the pressure-sensitive adhesive layer 3 (a coating solution for forming a pressure-sensitive adhesive layer) for forming the pressure-sensitive adhesive layer 3 is prepared (step 102: coating solution preparation step). The coating solution contains an acrylate copolymer that is a component of the pressure-sensitive adhesive layer 3, a radiation curable oligomer, and a crosslinking agent. And a coating solution is producible by throwing these into a solvent and stirring. As the solvent, for example, a general-purpose organic solvent such as toluene or ethyl acetate can be used.

And the adhesive layer 3 is formed on the base material 2 using the coating solution for the adhesive layer 3 produced at step 102 (step 103: adhesive layer formation process).
As a method of forming the pressure-sensitive adhesive layer 3 on the base material 2, a method of directly applying and drying a coating solution for the pressure-sensitive adhesive layer 3 on the base material 2, or for the pressure-sensitive adhesive layer 3 on a release liner. Any one of the methods in which the substrate 2 is bonded onto the pressure-sensitive adhesive layer 3 can be used.
Subsequently, the formed pressure-sensitive adhesive layer 3 is aged in an environment of, for example, 40 ° C. to 60 ° C. and thermally cured by crosslinking the acrylate copolymer and the crosslinking agent (step 104: thermosetting step). .

  According to the embodiment described in detail above, the functional group (any one functional group of hydroxyl group and carboxyl group) of the acrylate ester copolymer contained in the pressure-sensitive adhesive layer 3 is a functional group of the crosslinking agent. Reacts with the group. The radiation curable oligomer contained in the pressure-sensitive adhesive layer 3 has a weight average molecular weight Mw of 500 or more and 6000 or less, has 3 or more radiation-polymerizable carbon-carbon double bonds in the molecule, and a hydroxyl value of 3 mgKOH / g. It is as follows.

  The pressure-sensitive adhesive tape 1 of this embodiment can be used when dicing a semiconductor wafer to form individual semiconductor chips. In particular, it can be suitably used when a semiconductor wafer having an active surface on the surface is diced to form individual semiconductor chips.

That is, according to the pressure-sensitive adhesive tape 1 of the present embodiment, when the pressure-sensitive adhesive tape 1 is attached to a semiconductor wafer having an active surface, the pressure-sensitive adhesive layer 3 is irradiated with radiation to cure the pressure-sensitive adhesive layer 3. The adhesive strength of the agent layer 3 can be sufficiently reduced. In this case, individual semiconductor chips formed by dicing can be easily peeled off from the adhesive tape 1.
Therefore, even when the adhesive tape 1 of the present embodiment is attached to the surface of the semiconductor wafer that is an active surface by grinding the semiconductor wafer, dicing or individual semiconductors formed by dicing is used. Good chip pick-up.

  In addition, the adhesive tape 1 of this Embodiment may be a form wound in a roll shape or a form in which wide sheets are laminated. Moreover, the sheet-like or tape-like form formed by cutting the adhesive tape 1 of these forms into a predetermined size may be used.

<Semiconductor chip manufacturing method>
FIG. 3 is a flowchart illustrating a method for manufacturing a semiconductor chip using the adhesive tape 1 of the present embodiment. 4A to 4D are diagrams showing an example of manufacturing a semiconductor chip using the adhesive tape 1 of the present embodiment.

First, as shown in FIG. 4A, for example, a semiconductor wafer 100 having a plurality of integrated circuits 102 mounted on a substrate 101 containing silicon as a main component is prepared (step 201: preparation step).
Subsequently, the surface of the semiconductor wafer 100 opposite to the surface on which the integrated circuit 102 is mounted is ground, so that the semiconductor wafer 100 has a predetermined thickness (step 202: grinding process). At this time, although not shown, a protective tape is attached to the surface of the semiconductor wafer 100 on which the integrated circuit 102 is mounted. The protective tape is peeled off before the cutting (dicing) step.
And the adhesive tape 1 is affixed with respect to the semiconductor wafer 100 so that the grinding surface of the semiconductor wafer 100 may oppose the adhesive layer 3 of the adhesive tape 1 (step 203: pasting process). By sticking the adhesive tape 1 immediately after grinding the semiconductor wafer 100 in step 202, the adhesive tape 1 is attached to the semiconductor wafer 100 in a state where active atoms are present on the surface of the semiconductor wafer 100.

  Here, in the attaching step, the adhesive tape 1 is generally attached to the semiconductor wafer 100 using a pressing roll or the like that presses the adhesive tape 1. Alternatively, the adhesive tape 1 may be attached to the semiconductor wafer 100 by overlapping the semiconductor wafer 100 and the adhesive tape 1 in a pressurizable container (for example, an autoclave) and pressurizing the container. Further, the adhesive tape 1 may be attached to the semiconductor wafer 100 in a reduced pressure chamber (vacuum chamber).

  Subsequently, as shown in FIG. 4B, the semiconductor wafer 100 is cut by a dicer or the like along the planned cutting line X in a state where the adhesive tape 1 and the semiconductor wafer 100 are bonded together (step 204: cutting). Process). As shown in FIG. 4C, in this example, a so-called full cut is performed in which the entire semiconductor wafer 100 is cut.

  Here, in the cutting process, generally, a semiconductor is used, for example, by using a rotating blade while supplying cleaning water to a semiconductor wafer to which an adhesive tape has been attached in order to remove frictional heat and prevent adhesion of cutting waste. The wafer 100 is cut into a predetermined size. In order to make it easy to pick up individual semiconductor chips formed by dicing, the adhesive tape 1 may be stretched (expanded) after the cutting step.

Subsequently, by irradiating the adhesive tape 1 with radiation, the adhesive layer 3 is cured and contracted, and the adhesive force of the adhesive layer 3 is reduced (step 205: irradiation process).
Subsequently, as shown in FIG. 4D, a so-called pickup is performed to remove the semiconductor chip 200 formed by cutting the semiconductor wafer 100 from the adhesive tape 1 (step 206: peeling step).
Examples of the pickup method include a method in which the semiconductor chip 200 is pushed up by the needle 300 from the adhesive tape 1 side and the pushed-up semiconductor chip 200 is peeled off from the adhesive tape 1 using a pickup device (not shown). It is done.

  4A to 4D is an example of a method for manufacturing the semiconductor chip 200 using the adhesive tape 1, and the method of using the adhesive tape 1 is not limited to the above method. That is, the pressure-sensitive adhesive tape 1 of the present embodiment can be used without being limited to the above method as long as it can be attached to the semiconductor wafer 100 during dicing.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples without departing from the gist thereof.

The adhesive tape 1 shown in FIG. 1 was produced and evaluated.
[Preparation of adhesive tape 1]
Example 1
In this example, a polyolefin (PO) film having a thickness of 90 μm was used as the substrate 2.

Next, the pressure-sensitive adhesive layer 3 was formed on one surface side of the substrate 2 as follows.
First, 50 parts by mass of 2-ethylhexyl acrylate, 3 parts by mass of 2-hydroxyethyl acrylate, 37 parts by mass of methyl methacrylate, and 10 parts by mass of N-vinyl-2-pyrrolidone were mixed with an ethyl acetate solvent. Acrylic ester copolymer having a hydroxyl group (solid content concentration: 35% by mass) was prepared by radical copolymerization using azobisisobutyronitrile (AIBN) as an initiator. Here, methyl methacrylate was used to adjust the hardness of the pressure-sensitive adhesive layer 3.

Subsequently, in ethyl acetate, the prepared acrylate copolymer, radiation curable urethane acrylate oligomer, Tosoh Coronate (registered trademark) L as an isocyanate crosslinking agent, and a photopolymerization initiator Of BASF Japan Co., Ltd. was dissolved in Irgacure (registered trademark) 369 to prepare a coating solution for the pressure-sensitive adhesive layer 3.
Here, the composition of the coating solution is such that the radiation curable urethane acrylate oligomer is 120 parts by mass (solid content) and the coronate L is 7.5 parts by mass with respect to 100 parts by mass (solid content) of the acrylic ester copolymer. It was made for the mass part (solid content), Irgacure 369 to be 1.0 mass part (solid content), and ethyl acetate to be 343 mass parts.
As the radiation curable urethane acrylate oligomer, one having a weight average molecular weight Mw of 1000, a hydroxyl value of 1 mg KOH / g, and six radiation polymerizable carbon-carbon double bonds was used.

And the said application | coating solution is apply | coated to the peeling process surface side of a peeling liner (thickness 38 micrometers, polyester film) so that the thickness of the adhesive layer 3 after drying may be 10 micrometers, and it heats for 3 minutes at the temperature of 100 degreeC. After drying by doing, the base material 2 was bonded together on the adhesive layer 3, and the adhesive tape 1 was produced. Thereafter, the pressure-sensitive adhesive tape 1 was stored at a temperature of 40 ° C. for 72 hours to cure the pressure-sensitive adhesive layer 3.
The adhesive tape 1 of the present Example was produced by the above process.

(Examples 2 to 12)
An adhesive tape 1 was produced in the same manner as in Example 1 except that the radiation-curable urethane oligomer was changed as shown in FIG.

(Example 13)
For Example 1, the acrylic ester copolymer is changed to 3 parts by mass of 2-hydroxyethyl acrylate with 1 part by mass of methacrylic acid, thereby forming an acrylic ester copolymer having a carboxyl group. For the crosslinking agent, Example 1 except that 7.5 parts by mass of Coronate L, which is an isocyanate-based crosslinking agent, is changed to 2.5 parts by mass of Epolite 40E manufactured by Kyoeisha Chemical Co., which is an epoxy-based crosslinking agent. The adhesive tape 1 was produced in the same manner.

Comparative example

(Comparative Examples 1-4)
An adhesive tape was prepared in the same manner as in Example 1 except that the radiation curable urethane oligomer was changed as shown in FIG. Among these, in Comparative Example 1, the number of radiation-polymerizable carbon-carbon bonds in the molecule of the radiation-curable oligomer is two lower than the lower limit value. Moreover, in the comparative example 2, the weight average molecular weight Mw of a radiation-curable oligomer is 200 which is less than a lower limit. Moreover, in the comparative example 3, the weight average molecular weight Mw of a radiation-curable oligomer is 6500 exceeding an upper limit. In Comparative Example 4, the hydroxyl value of the radiation curable oligomer is 5 mg KOH / g exceeding the upper limit.

〔Evaluation method〕
(1) Adhesive strength test The adhesive strength test was done about the adhesive tape of Examples 1-13 and Comparative Examples 1-4.
Specifically, an adhesive tape was applied to the semiconductor wafer immediately after mirror polishing, and the semiconductor wafer was held for 7 days in an atmosphere at a temperature of 23 ° C. and a humidity of 50%. In order to apply the adhesive tape before the natural oxide film is formed on the ground surface of the semiconductor wafer, the adhesive tape was applied within 5 minutes after the grinding of the semiconductor wafer.
Subsequently, the adhesive tape was irradiated with ultraviolet rays (integrated light amount: 300 mJ / cm ² ). Then, under an environment of 23 ± 3 ° C., the force is applied in the direction along the surface of the adhesive tape, the adhesive tape is pulled at a pulling speed of 300 m / min, and the adhesive tape is peeled off from the semiconductor wafer. Went. That is, regarding the adhesive force, the evaluation is “◯” when the force required to peel the adhesive tape from the semiconductor wafer is 0.15 N / 10 mm or less, and the evaluation is “X” when the force is larger than 0.15 N / 10 mm. It was. In addition, evaluation of (circle) was set as the pass.

(2) Pickup test A pickup test was performed on the adhesive tapes of Examples 1 to 13 and Comparative Examples 1 to 4.
Specifically, the semiconductor wafer is ground to a thickness of 50 μm using DAG810 (product name) manufactured by DISCO Corporation, and then an adhesive tape is applied to the surface of the semiconductor wafer where active atoms are present. It was. Thereafter, dicing is performed using DFD 651 (product name, feed rate: 50 mm / min) manufactured by DISCO Corporation to form semiconductor chips each having a size of 100 mm ² , and then ultraviolet rays are applied from the base material side of the adhesive tape. (Integrated light amount: 300 mJ / cm ² ) was irradiated. Then, after the adhesive tape was stretched (expanded), the semiconductor wafer was picked up using WCS-700 (product name, number of pins: 5) manufactured by Daito Electron Co., Ltd., and the pick-up property was evaluated.
That is, picking up was performed for 50 arbitrary semiconductor elements, and the evaluation of “成功” was made when the picking up was successful without cracking all the semiconductor elements. Moreover, although cracks occurred in one or more and five or less semiconductor elements, the evaluation was evaluated as “Good” when the pickup was successful without cracking the remaining semiconductor elements. Moreover, it was set as evaluation of x when a crack generate | occur | produced about six or more semiconductor elements. In addition, evaluation of (circle) or (double-circle) was set as the pass.

(3) Measurement of storage elastic modulus About the adhesive tape of Examples 1-13 and Comparative Examples 1-4, the storage elastic modulus after radiation irradiation and hardening of each adhesive layer was measured.
Specifically, a sample was prepared by coating and drying each prepared pressure-sensitive adhesive layer so that the thickness after drying was 500 μm, and the pressure-sensitive adhesive layer was irradiated with ultraviolet rays (integrated light amount: 300 mJ / cm ² ). Then, using a viscoelasticity measuring device DMA6100 (product name) manufactured by Hitachi High-Tech Science Co., Ltd., dynamic viscoelasticity was measured to obtain a storage elastic modulus. The measurement conditions were a frequency of 1 Hz, a temperature increase rate of 2 ° C./min, and a numerical value of 23 ° C. as the storage elastic modulus.

〔Evaluation results〕
The evaluation results are shown in FIG.
About the adhesive tape of Examples 1-13, the adhesive force in the adhesive force test was a pass with a favorable result in all.
Moreover, about the adhesive tape of Examples 1-13, as for the pick-up property in a pick-up test, all passed with the favorable result of (double-circle) or (circle).
Furthermore, when Examples were compared in detail, Example 5 was slightly inferior in pick-up property because the hydroxyl value of the radiation curable oligomer was 3 mg KOH / g (upper limit value) (number of cracks in semiconductor element: 1). .
Further, in Example 8, the content of the radiation curable oligomer was as relatively small as 50 parts by mass, so that the storage elastic modulus was somewhat low as 7.0 × 10 ⁵ Pa and the pickup property was slightly inferior (semiconductor element cracking). Number: 2).
In Example 9, since the weight average molecular weight Mw of the radiation curable oligomer is slightly small as 800 and the content is slightly large as 170 parts by mass, the storage elastic modulus is slightly high as 1.0 × 10 ⁹ Pa, and the pickup property is high. Slightly inferior (number of cracks in semiconductor element: 1).
In Example 11, the content of the radiation curable oligomer was slightly high at 180 parts by mass, so that the storage elastic modulus was slightly high as 7.5 × 10 ⁸ Pa and the pickup property was slightly inferior (semiconductor element). Number of cracks: 1).
Further, in Example 12, the content of the radiation curable oligomer was relatively high at 190 parts by mass, so that the storage elastic modulus was somewhat high as 1.0 × 10 ⁹ Pa and the pick-up property was slightly inferior (semiconductor element cracking). Number: 2).

On the other hand, about the adhesive tape of the comparative example 1 and the comparative examples 3 and 4, in the adhesive force test, the adhesive force of the adhesive layer was excessively large and was disqualified by evaluation of x.
Moreover, about the adhesive tape of Comparative Examples 1-4, all were disqualified by evaluation of x about the pick-up property in a pick-up test.
That is, in Comparative Example 1, the number of radiation-polymerizable carbon-carbon bonds in the molecule of the radiation-curable oligomer is two lower than the lower limit, and the adhesive layer cannot be sufficiently cured / contracted after irradiation. Since the force was not sufficiently reduced, it became difficult to peel the separated semiconductor chip from the adhesive tape, and the pick-up property was lowered.
In Comparative Example 2, the weight average molecular weight Mw of the radiation curable oligomer is 200 lower than the lower limit, and the adhesive strength decreases after irradiation, but it becomes hard due to the effect of increasing the crosslink density between the oligomers, and bending elasticity. Since the rate increased, cracks occurred when the separated semiconductor chip was peeled off from the adhesive tape, and the pick-up property was lowered.
In Comparative Example 3, the weight average molecular weight Mw of the radiation curable oligomer was 6500 exceeding the upper limit value, and the adhesive layer was not sufficiently cured / contracted after irradiation, and the adhesive strength was not sufficiently reduced. As a result, it became difficult to peel the separated semiconductor chip from the adhesive tape, and the pick-up property was lowered.
Moreover, in Comparative Example 4, the hydroxyl value of the radiation curable oligomer is 5 mg KOH / g exceeding the upper limit, and the adhesive force is excessively large when the adhesive tape is applied to the semiconductor wafer immediately after mirror polishing. Thus, the adhesive strength did not sufficiently decrease even when irradiated with radiation, so that it was difficult to peel the separated semiconductor chip from the adhesive tape, and the pick-up property was deteriorated.

  According to the results of Examples 1 to 13 and Comparative Examples 1 to 4, the acrylate copolymer has any one of a hydroxyl group and a carboxyl group as a functional group, and a radiation curable oligomer, It was confirmed that the weight average molecular weight Mw was 500 or more and 6000 or less, the molecule had three or more radiation-polymerizable carbon-carbon double bonds, and the hydroxyl value was 3 mgKOH / g or less.

DESCRIPTION OF SYMBOLS 1 ... Adhesive tape, 2 ... Base material, 3 ... Adhesive layer

Claims (5)

A substrate;
A pressure-sensitive adhesive layer provided on at least one surface side of the substrate;
Have
The pressure-sensitive adhesive layer includes at least an acrylic ester copolymer having one of a hydroxyl group and a carboxyl group as a functional group, and a weight average molecular weight Mw of 500 to 6000, and radiation-polymerizable in the molecule. A radiation curable oligomer having 3 or more carbon-carbon double bonds and a hydroxyl value of 3 mgKOH / g or less, a crosslinking agent that reacts with the functional group of the acrylate copolymer,
Dicing adhesive tape comprising 2. The adhesive for dicing according to claim 1, wherein the adhesive layer has a storage elastic modulus of 1.0 × 10 ⁶ Pa or more and 7.0 × 10 ⁸ Pa or less after being cured by irradiation with radiation. tape.   The said adhesive layer contains 80 mass parts or more and 180 mass parts or less of the said radiation curable oligomers when the said acrylic ester copolymer is 100 mass parts. Dicing adhesive tape. A substrate preparation step of preparing a substrate;
A coating solution for forming a pressure-sensitive adhesive layer, and at least an acrylate copolymer having at least one of a hydroxyl group and a carboxyl group as a functional group, and a weight average molecular weight Mw of 500 or more and 6000 or less. Reacts with the radiation-curable oligomer having 3 or more radiation-polymerizable carbon-carbon double bonds in the molecule and a hydroxyl value of 3 mgKOH / g or less, and the functional group of the acrylate copolymer. A coating solution preparation step of preparing a coating solution containing a crosslinking agent;
Using the coating solution, an adhesive layer forming step of forming the adhesive layer on at least one surface side of the substrate;
Including a treatment of crosslinking the acrylic ester copolymer and the crosslinking agent, and a thermosetting step of thermosetting the formed pressure-sensitive adhesive layer;
The manufacturing method of the adhesive tape for dicing containing. A sticking step of attaching the dicing adhesive tape to the element substrate on which a plurality of semiconductor elements are formed on the substrate;
A cutting step of cutting the substrate for elements to which the adhesive tape for dicing is affixed into a plurality of semiconductor chips;
An irradiation step of irradiating the dicing adhesive tape attached to the semiconductor chip with radiation to reduce the adhesive strength of the dicing adhesive tape;
A peeling step of peeling off the semiconductor chip from the adhesive tape for dicing with reduced adhesive strength,
Including
The dicing adhesive tape is
A substrate;
A pressure-sensitive adhesive layer provided on at least one surface side of the substrate;
Have
The pressure-sensitive adhesive layer includes at least an acrylic ester copolymer having one of a hydroxyl group and a carboxyl group as a functional group, and a weight average molecular weight Mw of 500 to 6000, and radiation-polymerizable in the molecule. A radiation curable oligomer having 3 or more carbon-carbon double bonds and a hydroxyl value of 3 mgKOH / g or less, a crosslinking agent that reacts with the functional group of the acrylate copolymer,
A method of manufacturing a semiconductor chip comprising:

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