JP5461292B2 - Dicing adhesive film and method for producing cut piece - Google Patents

Description

  The present invention relates to a dicing adhesive film and a method for producing a cut piece. In particular, the present invention relates to an improvement in a radiation-curable pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer of a dicing pressure-sensitive adhesive film.

  2. Description of the Related Art Conventionally, semiconductor-related materials for semiconductor wafers and semiconductor packages are cut using a cutting blade such as 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 back-grinded (back grind) until a predetermined thickness is obtained. Back surface processing (etching processing, polishing processing, etc.) is performed. Next, the semiconductor wafer is cut and separated (diced) into element pieces, and then transferred to the subsequent process. In this manufacturing process, the mounting step of pasting the semiconductor wafer to the adhesive film for dicing in advance, the dicing step of dicing the semiconductor wafer into semiconductor element pieces in a state where the adhesive film is pasted on the semiconductor wafer, the cleaning step, the expanding step, Various processes such as a pickup process are performed. In the pick-up step, the dicing adhesive film is stretched to some extent, the dicing adhesive film below the semiconductor element to be picked up is lifted in a dotted or linear shape, and the semiconductor element and the dicing adhesive film are peeled off. A method of picking up a semiconductor element from the upper part by vacuum suction or the like while being promoted is employed.

  The dicing pressure-sensitive adhesive film generally has a configuration in which a pressure-sensitive adhesive layer containing a pressure-sensitive adhesive composition is formed on a substrate such as a plastic film. When manufacturing a semiconductor element, the dicing adhesive film does not peel from the adhesive film even if water pressure of washing water is applied during dicing in order to suppress the detachment and scattering of the semiconductor element from the adhesive film in the dicing process. While a high degree of adhesive strength is required, it is required that the adhesive layer has a light release property that provides a low adhesive strength that does not damage the semiconductor wafer during peeling in the pickup process.

  The dicing pressure-sensitive adhesive film satisfying the above-mentioned characteristics includes a base polymer in which a functional group such as a hydroxyl group is introduced on a radiation transmissive substrate, a functional group that reacts with the hydroxyl group, and a radiation-reactive carbon-carbon. (Meth) acrylic polymers obtained by reacting radiation-reactive compounds with double bonds in the molecule, and low molecular weight polyfunctional polymerizations such as polyfunctional monomers and polyfunctional oligomers to accelerate curing by radiation A dicing pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer made of a so-called blend-type radiation-curable pressure-sensitive adhesive composition containing a functional compound is formed is widely used (for example, Patent Document 1). In this kind of pressure-sensitive adhesive film for dicing, the radiation-curable pressure-sensitive adhesive composition has a high adhesive strength before being cured by radiation, and therefore, desorption and scattering of the semiconductor element can be suppressed in the dicing process. Further, when the pressure-sensitive adhesive layer is irradiated with radiation, the radiation-curable pressure-sensitive adhesive composition is cured and the adhesive strength is reduced, so that the semiconductor element can be easily peeled from the dicing pressure-sensitive adhesive film in the pickup process.

  By the way, in recent years, in the semiconductor manufacturing process, within a short time after the back surface grinding process or after the back surface grinding process and the back surface process are completed, for the purpose of preventing damage due to the thinning of the semiconductor wafer (for example, 100 μm or less). In addition, an adhesive film for dicing is often attached to a semiconductor wafer. After such back grinding, or after back grinding and back treatment, if the adhesive film for dicing is attached to a thin semiconductor wafer within a short time, the adhesive strength between the semiconductor wafer and the adhesive layer is increased, There is a problem that peeling after curing by radiation is difficult and pick-up property is lowered. This is because the natural oxide film is not sufficiently formed on the entire surface of the semiconductor wafer on the processed surface where the backside grinding process or the backside processing of the semiconductor wafer is performed, and the surface of the semiconductor wafer is not oxidized in the active atoms (for example, Therefore, when a dicing adhesive film is bonded to the active surface, the unoxidized active atom and the radiation-curable adhesive composition of the adhesive layer are formed. It is inferred that a chemical bond is generated between the non-oxidized active atom and the radiation curable pressure-sensitive adhesive composition upon contact.

  The blend-type radiation-curable pressure-sensitive adhesive composition as in Patent Document 1 is not only (meth) acrylic polymers having radiation-reactive carbon-carbon double bonds, but also ( Since the (meth) acrylic polymer also reacts with the low molecular weight polyfunctional polymerizable compound, the adhesive strength can be reduced after curing by radiation, and it is also suitably used for workpieces having the above active surface. It is considered possible.

  However, according to the study by the present inventors, a semiconductor wafer having an active surface is diced even if a radiation curable pressure-sensitive adhesive composition containing the low molecular weight polyfunctional polymerizable compound as described above is used. When picking up an element, it has become clear that the pickup property is not sufficiently improved. This is thought to be because the bond between the (meth) acrylic polymer that is the main component of the radiation-curable pressure-sensitive adhesive composition and the active surface is strong. Moreover, when a low molecular weight polyfunctional polymerizable compound is used in a large amount, free low molecular weight components increase in the radiation curable pressure-sensitive adhesive composition, and the adhesive strength before curing by radiation decreases. In particular, in the dicing process, the pressure-sensitive adhesive layer is attached to a ring frame made of metal such as SUS or resin, and the radiation-curable pressure-sensitive adhesive composition containing a low molecular weight polyfunctional polymerizable compound is used in these rings. There is a problem of low adhesion to the frame.

  Further, in the manufacture of a semiconductor element, it is required that no chipping (chip chipping) occurs on the back surface or side surface of the semiconductor element during dicing. When such chipping occurs, the bending strength of the semiconductor element itself is reduced, and air is likely to be caught in the sealed IC package, which easily causes package cracks. This chipping is caused by the semiconductor element being vibrated by the cutting blade during dicing, causing the semiconductor element to be misaligned or lifted. Therefore, there is a demand for a dicing pressure-sensitive adhesive film including a pressure-sensitive adhesive layer having a high cohesive force that can reduce the positional deviation of a semiconductor element even when vibration is applied by a cutting blade during dicing.

  When enhancing the cohesive strength of the radiation-curable pressure-sensitive adhesive composition containing the (meth) acrylic polymer as described above, the radiation-curable pressure-sensitive adhesive is obtained by three-dimensionally cross-linking the (meth) acrylic polymer using a crosslinking agent. It is effective to increase the holding power of the composition. Therefore, also in Patent Document 1, radiation containing a (meth) acrylic polymer and a crosslinking agent having a functional group such as an isocyanate group or an epoxy group that crosslinks with a hydroxyl group of the (meth) acrylic polymer in the molecule. A curable pressure-sensitive adhesive composition is used.

  However, when synthesizing a (meth) acrylic polymer having a radiation-reactive carbon-carbon double bond in the molecule as described above, it is necessary to react the hydroxyl group introduced into the base polymer with the functional group of the radiation-reactive compound. Therefore, even if the content of the crosslinking agent is simply increased, if the (meth) acrylic polymer has few hydroxyl groups that react with the crosslinking agent, the crosslinking reaction will occur between the (meth) acrylic polymer and the crosslinking agent. Not only does this occur sufficiently, but only low molecular weight components increase, and not only a high holding power cannot be obtained, but also there is a problem that the paste stains increase on the cut piece and the contamination is deteriorated.

JP 2007-220694 A

  The present invention has been made in order to solve the above-mentioned problems. The object of the present invention is to have a high adhesive force and a high holding force with respect to a workpiece such as a semiconductor wafer and a ring frame before being cured by radiation. Provided a dicing pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer containing a radiation-curable pressure-sensitive adhesive composition having excellent light releasability and low contamination even for a workpiece having an active surface after curing by radiation In addition, by using the above-mentioned adhesive film for dicing, it is possible to reduce chipping by suppressing vibration of the cut piece and suppressing chipping in the dicing process, and in the pickup process. To provide a manufacturing method that can easily peel off an adhesive film for dicing and a cut piece with less adhesive stains. A.

The present invention is a pressure-sensitive adhesive film for dicing comprising a base material and a pressure-sensitive adhesive layer containing a radiation-curable pressure-sensitive adhesive composition on the base material,
The radiation-curable pressure-sensitive adhesive composition has at least an alkyl group-containing (meth) acrylic monomer and a hydroxyl group-containing (meth) acrylic monomer as a copolymerization monomer component, and 9.6 (cal / cm ³ ) ^{1 /} A base polymer having a solubility parameter of ² or more and 10.0 (cal / cm ³ ) ^1/2 or less, a first functional group that reacts with a hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer, and With respect to 100 parts by weight of the (meth) acrylic polymer obtained by reacting with a radiation reactive compound having a radiation reactive carbon-carbon double bond in the molecule, and 100 parts by weight of the (meth) acrylic polymer, the hydroxyl group Containing 0.3 to 2.7 parts by mass of a crosslinking agent having a second functional group that undergoes a crosslinking reaction in the molecule,
The hydroxyl group-containing (meth) acrylic monomer, the radiation-reactive compound, and the crosslinking agent have a molar amount of a hydroxyl group introduced into the base polymer by the hydroxyl-containing (meth) acrylic monomer. More than the total molar amount of the first functional group and the second functional group of the crosslinking agent, the residual hydroxyl group concentration after the crosslinking reaction is 0.08 mmol or less per 1 g of the radiation curable pressure-sensitive adhesive composition, and the radiation reactive compound The concentration of the radiation-reactive carbon-carbon double bond introduced into the (meth) acrylic polymer by 0.45 mmol or more and 0.84 mmol or less per 1 g of the radiation-curable pressure-sensitive adhesive composition. It is an adhesive film for dicing.

The radiation-curable pressure-sensitive adhesive composition is obtained using a base polymer having a solubility parameter of 9.6 (cal / cm ³ ) ^1/2 or more and 10.0 (cal / cm ³ ) ^1/2 or less ( Since it contains a (meth) acrylic polymer, the resulting (meth) acrylic polymer has few polar sites, and the polar sites are likely to be concealed. As a result, binding between active atoms and polar sites is suppressed, resulting in radiation. Adhesive strength after curing can be sufficiently reduced.

  The radiation-curable pressure-sensitive adhesive composition has a second functional group that undergoes a crosslinking reaction with a hydroxyl group introduced into the base polymer by a hydroxyl group-containing (meth) acrylic monomer in order to improve the retention before curing by radiation. A certain amount of the crosslinking agent contained in the molecule is contained, but the molar amount of the hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer depends on the first functional group of the radiation reactive compound and the second amount of the crosslinking agent. A hydroxyl group-containing (meth) acrylic monomer, a radiation-reactive compound, and a cross-linking agent are blended so that the total molar amount of functional groups is equal to or greater. Even after a carbon-carbon double bond is introduced, a hydroxyl group capable of undergoing a crosslinking reaction with a crosslinking agent can be secured in the (meth) acrylic polymer. As a result, there are fewer free low molecular weight components in the radiation curable pressure-sensitive adhesive composition, and it has a high adhesive force on a semiconductor wafer or metal member before curing by radiation, and has a high holding power, After curing with radiation, a radiation curable pressure-sensitive adhesive composition having low contamination can be obtained.

  Further, in the radiation curable pressure-sensitive adhesive composition, the hydroxyl group-containing (meth) acrylic monomer, radiation, and the residual hydroxyl group concentration after the crosslinking reaction are 0.08 mmol or less per 1 g of the radiation curable pressure-sensitive adhesive composition. Since the reactive compound and the crosslinking agent are blended, the molar amount of the hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer is such that the first functional group of the radiation reactive compound and the second amount of the crosslinking agent. Even after the total molar amount of the functional groups, there is little residual hydroxyl group in the entire radiation-curable pressure-sensitive adhesive composition after the crosslinking reaction, and therefore the workpiece having an active surface is also cured by irradiation with radiation. Can be sufficiently reduced.

  And in the said radiation curable adhesive composition, the radiation reactive carbon-carbon double bond density | concentration introduce | transduced into the (meth) acrylic-type polymer with the radiation reactive compound is 0 per 1g of radiation curable adhesive compositions. Since the hydroxyl group-containing (meth) acrylic monomer, the radiation-reactive compound, and the crosslinking agent are blended so as to be .42 mmol or more and 0.84 mmol or less, the adhesive strength and holding power before curing by radiation are reduced. Without using low molecular weight polyfunctional polymerizable compounds such as polyfunctional monomers and polyfunctional oligomers, the adhesive strength after curing by radiation can be sufficiently reduced.

  In the present specification, (meth) acryl means acryl or methacryl.

  The radiation curable pressure-sensitive adhesive composition preferably contains substantially no low molecular weight polyfunctional polymerizable compound. According to the dicing pressure-sensitive adhesive film, a dicing pressure-sensitive adhesive film having a high adhesive force and a high holding force before being cured by radiation can be obtained.

And this invention affixes the adhesive film for dicing as described above on one surface of the workpiece,
The workpiece to which the adhesive film for dicing is attached is cut and separated into cut pieces,
Radiation is applied to the adhesive layer attached to the cut piece to reduce the adhesive strength of the adhesive layer,
It is the manufacturing method of the cut piece which picks up the said cut piece from the adhesive film for dicing which reduced the said adhesive force. In particular, when the workpiece is a semiconductor wafer having an active surface, the method for manufacturing the cut piece is effective.

  According to the above manufacturing method, since the dicing adhesive film contains the radiation curable adhesive composition, in the dicing step, it is possible to reduce detachment scattering of the cut pieces and to suppress vibration of the cut pieces. Chipping can be reduced. Even when a workpiece having an active surface is used, in the pick-up process, it is possible to reduce glue stains and to easily peel off the dicing adhesive film and the cut piece.

  As described above, according to the present invention, it has a high adhesive force and a high holding force before being cured by radiation, and has a low adhesive force even to a workpiece having an active surface after being cured by radiation. An adhesive film for dicing can be provided. As a result, in the dicing process, the separation and scattering of the cut pieces can be reduced, the vibration of the cut pieces can be suppressed, and chipping can be reduced. Further, in the pick-up process, the cut piece can be easily peeled off from the dicing adhesive film on a workpiece such as a semiconductor wafer having an active surface, and glue stains on the cut piece can be reduced.

FIG. 1 is a schematic cross-sectional view showing an example of a dicing adhesive film according to an embodiment of the present invention.

  As described above, a pressure-sensitive adhesive layer made of a radiation-curable pressure-sensitive adhesive composition containing a (meth) acrylic polymer into which a radiation-reactive carbon-carbon double bond was introduced was attached to a semiconductor wafer having an active surface. In this case, the adhesive strength does not sufficiently decrease even when irradiated with radiation, and it becomes difficult to peel the semiconductor element from the adhesive layer, and the pick-up property is likely to decrease. This is presumed to be because the unoxidized active atoms on the active surface come into contact with polar sites such as ester groups and hydroxyl groups of the (meth) acrylic polymer, and chemical bonds are formed between them. . That is, in the synthesis of a (meth) acrylic polymer having a radiation-reactive carbon-carbon double bond, an alkyl group-containing (meth) acrylic monomer that is an adhesive component, a functional group of a radiation-reactive compound or a crosslinking agent, First, a base polymer having an ester group or a hydroxyl group at the terminal or side chain is synthesized by polymerizing a copolymerization monomer component having at least a hydroxyl group-containing (meth) acrylic monomer for introducing a reactive hydroxyl group. It is necessary to react a radiation reactive compound having a functional group capable of reacting with a hydroxyl group introduced into the base polymer with the base polymer. Therefore, the (meth) acrylic polymer not only has an ester group, but the (meth) acrylic polymer may have an unreacted hydroxyl group remaining from the functional group of the radiation reactive compound and the functional group of the crosslinking agent. These polar sites are thought to form chemical bonds with the active atoms.

In order to reduce the adhesive strength of the dicing adhesive film affixed to a semiconductor wafer having an active surface by irradiation with radiation, the present inventors can suppress the bonding between the polar sites and active atoms as much as possible. From the viewpoint of effectiveness, the characteristics of the (meth) acrylic polymer, which is the main component of the radiation-curable pressure-sensitive adhesive composition, were first examined. As a result, the solubility parameter of the base polymer constituting the (meth) acrylic polymer was 9.6. If it is (cal / cm ³ ) ^1/2 or more and 10.0 (cal / cm ³ ) ^1/2 or less, it has a high adhesive force before curing with radiation and has a light peelability after curing with radiation. It has been found that a radiation-curable pressure-sensitive adhesive composition can be obtained.

  That is, if the high adhesive force between the semiconductor wafer having an active surface after curing by radiation and the adhesive layer is due to the bond between the active atom and the polar part of the (meth) acrylic polymer, the solubility parameter decreases. Means a decrease in polarity. Therefore, if a base polymer having a low solubility parameter is used, the number of polar sites of the obtained (meth) acrylic polymer can be reduced. In addition, in the alkyl group-containing (meth) acrylic monomer, the solubility parameter decreases as the alkyl chain becomes longer, so that the polar site can be concealed by the long chain alkyl group. Thereby, the coupling | bonding of an active atom and a polar site | part can be decreased. On the other hand, when the solubility parameter is too low, the number of hydroxyl groups in the base polymer for introducing a radiation-reactive carbon-carbon double bond decreases. Therefore, the amount of radiation-reactive carbon-carbon double bonds introduced into the (meth) acrylic polymer is reduced, and the curability when irradiated with radiation is reduced. In addition, when a crosslinking agent is used to crosslink the (meth) acrylic polymer, polar groups such as hydroxyl groups that react with the crosslinking agent are reduced, leaving unreacted components in the pressure-sensitive adhesive layer, and curing by radiation. The previous adhesive strength is reduced, and adhesive stains are likely to occur.

In this Embodiment, the solubility parameter of a base polymer can be calculated | required from the product of the solubility parameter and molar ratio of each (meth) acrylic-type monomer which comprises the base polymer which is a copolymer. For example, when the base polymer is composed of two types of (meth) acrylic monomers X and Y, the content of each (meth) acrylic monomer used to synthesize the base polymer with respect to the total amount of copolymerization monomer components Is x mass%, y mass%, and the molecular weight is Mx and My, the molar ratio Cx and Cy of each (meth) acrylic monomer is represented by x / Mx and y / My, and the molar ratio C of the base polymer is , X / Mx + y / My. Therefore, when the solubility parameter of each (meth) acrylic monomer is SPx (cal / cm ³ ) ^1/2 and SPy (cal / cm ³ ) ^1/2 , the solubility parameter SP (cal / cm ³ ) ^{1 of the} base polymer. ^{/ 2} can be obtained by the following equation (1).
SP = [(x × SPx / Mx) + (y × SPy / My)] × (1 / C) (1)

  In addition, it is known that the solubility parameter of each (meth) acrylic monomer is calculated from the molecular structure, and the solubility parameter of each (meth) acrylic monomer in this specification is the Fedors method (written by Yuji Harasaki, It means the value at 25 ° C. obtained by “Basic Science of Coating”, Chapter 3, page 35, 1977, published by Sakai Shoten.

  Next, in order to improve the light peelability of the dicing pressure-sensitive adhesive film, it is necessary to improve the curability of the entire radiation-curable pressure-sensitive adhesive composition. In this case, if only a decrease in the adhesive strength after curing by radiation is required, in addition to the (meth) acrylic polymer having a radiation-reactive carbon-carbon double bond introduced, such as a blend type, a polyfunctional monomer or polyfunctional It is also conceivable to use low molecular weight polyfunctional polymerizable compounds such as oligomers. However, even when these low molecular weight polyfunctional polymerizable compounds are used, pick-up properties are not improved when a workpiece having an active surface is used. The adhesive strength and holding power of the are reduced. In order to achieve both high adhesive strength before curing by radiation and low adhesive strength after curing by radiation, it may be possible to increase the radiation-reactive carbon-carbon double bond introduced into the (meth) acrylic polymer itself. In the (meth) acrylic polymer of the present embodiment, the radiation-reactive carbon-carbon double bond is composed of a hydroxyl group introduced into the base polymer by a hydroxyl group-containing (meth) acrylic monomer and a function of the radiation-reactive compound. It is introduced into a (meth) acrylic polymer by reacting with a group. Therefore, when most of the hydroxyl groups introduced into the base polymer are used for introduction of the radiation-reactive carbon-carbon double bond, there are few hydroxyl groups for crosslinking reaction between the (meth) acrylic polymer and a certain amount of the crosslinking agent. As a result, the holding power is lowered and the contamination is deteriorated. On the other hand, if the introduction amount of the radiation reactive carbon-carbon double bond is too small, the (meth) acrylic polymer is not sufficiently cured even by irradiation with radiation, and the adhesive strength after curing by radiation is sufficiently reduced. It will not be possible. Further, even if the amount of hydroxyl group introduced into the base polymer is increased, a large amount of hydroxyl group remains in the (meth) acrylic polymer when a small amount of a radiation reactive compound or a crosslinking agent is used. As a result, even when a (meth) acrylic polymer having the above low solubility parameter is used, the residual hydroxyl group and the active atom are bonded to each other, and the adhesive force after curing by radiation is not sufficiently lowered, or three-dimensional Since the crosslinked structure is not sufficiently formed, the holding power before curing by radiation is reduced.

  Therefore, in order to achieve both high adhesive strength and high holding power before curing by radiation, and low adhesive strength and low contamination after curing by radiation, it is introduced into the base polymer by a hydroxyl group-containing (meth) acrylic monomer. Hydroxyl group content, radiation-reactive carbon-carbon double bond content introduced into the (meth) acrylic polymer by reaction with the hydroxyl group, content of the crosslinking agent that undergoes crosslinking reaction with the hydroxyl group, and hydroxyl group remaining after the crosslinking reaction The amount needs to be considered.

  From this point of view, as a result of studying the structure of the radiation curable pressure-sensitive adhesive composition as a whole, the hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer was cross-linked in order to improve the holding power before curing by radiation. A certain amount of a crosslinking agent having a second functional group that reacts in the molecule is used, and the molar amount of the hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer is determined as the first functional group of the radiation-reactive compound. When the total molar amount of the second functional group of the crosslinking agent is not less than the total molar amount, the hydroxyl group introduced into the base polymer and the first functional group of the radiation reactive compound can be reacted, and the base polymer and the radiation reactive compound Even after a radiation-reacting carbon-carbon double bond is introduced by reacting with Such because a hydroxyl group remains, it is possible to react the second functional group of the hydroxyl group and the crosslinking agent. As a result, the amount of free low molecular weight components in the radiation curable pressure-sensitive adhesive composition is reduced, and it has a high adhesive force on a semiconductor wafer and a metal member before being cured by radiation, and has a high holding power, and radiation. A radiation-curable pressure-sensitive adhesive composition having low contamination can be obtained after curing by the above method.

  On the other hand, if the molar amount of the hydroxyl group is excessively large relative to the total molar amount of the first functional group of the radiation-reactive compound and the second functional group of the crosslinking agent, the residual hydroxyl group concentration after the crosslinking reaction increases, Due to the bond between the active atom and the active atom, the adhesive strength is not sufficiently reduced even after curing by radiation, and the light peelability is deteriorated. However, if the residual hydroxyl group concentration after the crosslinking reaction is 0.08 mmol or less per 1 g of the radiation curable pressure-sensitive adhesive composition, the molar amount of the hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer, Workpiece having less residual hydroxyl groups in the entire radiation-curable pressure-sensitive adhesive composition and therefore having an active surface even if the total molar amount of the first functional group of the radiation-reactive compound and the second functional group of the crosslinking agent is greater than In contrast, the adhesive strength after curing by radiation can be sufficiently reduced. For this reason, the residual hydroxyl group concentration is preferably as low as possible, preferably 0 mmol. When the residual hydroxyl group concentration is confirmed from the radiation curable pressure-sensitive adhesive composition after the crosslinking reaction, the residual hydroxyl group concentration can be calculated by measuring the hydroxyl value of the radiation curable pressure-sensitive adhesive composition.

  Furthermore, the radiation-reactive carbon-carbon double bond concentration introduced into the (meth) acrylic polymer by the radiation-reactive compound is 0.42 mmol or more and 0.84 mmol or less, preferably 1 g of the radiation-curable pressure-sensitive adhesive composition. Is 0.42 mmol or more and 0.69 mmol or less, without using a low molecular weight polyfunctional polymerizable compound such as a polyfunctional monomer or polyfunctional oligomer that reduces the adhesive strength and holding power before curing by radiation, The adhesive strength after curing by can be sufficiently reduced. When the radiation-reactive carbon-carbon double bond concentration per 1 g of the radiation-curable pressure-sensitive adhesive composition is less than 0.42 mmol, there are few radiation-reactive carbon-carbon double bonds in the radiation-curable pressure-sensitive adhesive composition, and due to radiation. The adhesive strength after curing does not decrease sufficiently. On the other hand, when the radiation reactive carbon-carbon double bond concentration per 1 g of the radiation curable pressure-sensitive adhesive composition is more than 0.84 mmol, the (meth) acrylic polymer is secured with a hydroxyl group for crosslinking reaction with the crosslinking agent. Cannot be retained and the holding power is reduced or the contamination is deteriorated. In addition, when confirming the radiation-reactive carbon-carbon double bond concentration in the radiation-curable pressure-sensitive adhesive composition, the radiation-reactive carbon-carbon double is determined by measuring the iodine value of the radiation-curable pressure-sensitive adhesive composition. The binding concentration can be calculated.

  Next, each component which comprises the radiation-curable adhesive composition of this Embodiment, and the manufacturing method of the adhesive film for dicing using this and a cutting piece are demonstrated concretely.

  In the present embodiment, the base polymer contains at least an alkyl group-containing (meth) acrylic monomer having no polar group such as a hydroxyl group and a hydroxyl group-containing (meth) acrylic monomer as a copolymerization monomer component. As the alkyl group-containing (meth) acrylic monomer, an alkyl group-containing (meth) acrylic monomer having a linear or branched alkyl group having 2 or more, preferably 8 or more carbon atoms is used. In particular, if the base polymer contains only an alkyl group-containing (meth) acrylic monomer having a linear or branched alkyl group having 8 or more carbon atoms and a hydroxyl group-containing (meth) acrylic monomer as a copolymerization monomer component, The polar site of the (meth) acrylic polymer is concealed by a long-chain alkyl group, thereby preventing contact between the ester group and the active atom.

  Specific examples of the alkyl group-containing (meth) acrylic monomer include, for example, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth) Isobutyl 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, tridecyl (meth) acrylate, (meth) acrylic Le acid tetradecyl, (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl include (meth) acrylic acid esters such as (meth) octadecyl acrylate. These may be used alone or in combination. The number of alkyl groups in the alkyl group-containing (meth) acrylic monomer is preferable because the longer the chain, the more the polar site is concealed. However, considering the availability in the market, the number of alkyl groups is preferably 18 or less. More preferably, it is 12 or less. Among these, one kind selected from the group consisting of octyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate containing a linear or branched alkyl group having 8 carbon atoms is preferable. More preferred is 2-ethylhexyl (meth) acrylate.

  Specific examples of the hydroxyl group-containing (meth) acrylic monomer include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth ) 6-hydroxyhexyl acrylate and the like. These may be used alone or in combination.

  The content of the alkyl group-containing (meth) acrylic monomer is preferably 87.5 to 93.5% by mass with respect to the total amount of copolymerization monomer components constituting the base polymer, and the hydroxyl group-containing (meth) acrylic monomer The content of is preferably 6.5 to 12.5% by mass. In particular, a base polymer containing 80.0 to 93.5% by mass of an alkyl group-containing (meth) acrylic monomer having a linear or branched alkyl group having 8 or more carbon atoms, based on the total amount of the copolymerization monomer component. More preferred. If the content of the alkyl group-containing (meth) acrylic monomer is too low and the content of the hydroxyl group-containing (meth) acrylic monomer is too high, the solubility parameter of the base polymer becomes too high and the residual hydroxyl group concentration becomes high. The adhesive force cannot be sufficiently reduced even by curing with radiation, and as a result, the light peelability is deteriorated. On the other hand, if the content of the alkyl group-containing (meth) acrylic monomer is too large and the content of the hydroxyl group-containing (meth) acrylic monomer is too small, the amount of hydroxyl group introduced into the base polymer decreases, resulting in radiation. The hydroxyl group necessary for reacting with the reactive compound to introduce a radiation-reactive carbon-carbon double bond into the (meth) acrylic polymer is reduced, and the curability is lowered. Moreover, when the introduction amount of the radiation-reactive carbon-carbon double bond is increased in order to improve curability, the number of hydroxyl groups that react with the cross-linking agent decreases, and the holding power decreases.

  The base polymer may contain other copolymerization monomer components as necessary for the purpose of cohesion and heat resistance. As such other copolymerization monomer components, specifically, for example, an epoxy group-containing monomer such as glycidyl (meth) acrylate; (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, Carboxyl group-containing monomers such as isocrotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N- Amide monomers such as methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; aminoethyl (meth) acrylate, (meth) acrylic Acid N, N-dimethylaminoethyl, ) Amino group-containing monomers such as t-butylaminoethyl acrylate; Cyano group-containing monomers such as (meth) acrylonitrile; Olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; Styrene, α-methylstyrene, vinyltoluene Styrene monomers such as vinyl ester monomers such as vinyl acetate and vinyl propionate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; methoxyethyl (meth) acrylate, Alkoxy group-containing monomers such as ethoxyethyl (meth) acrylate; N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N- Contains nitrogen atoms such as nilpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- (meth) acryloylmorpholine Examples include monomers having a ring. Moreover, you may use a polyfunctional monomer for a copolymerization monomer component as needed for the purpose of bridge | crosslinking etc. Furthermore, as a copolymerization monomer component, an ethylene-vinyl acetate copolymer, a vinyl acetate polymer, or the like may be used as necessary. These other copolymerizable monomer components may be used alone or in combination. However, in order to obtain a base polymer having the above solubility parameter, the content of the polar group-containing (meth) acrylic monomer having a polar group other than the hydroxyl group-containing (meth) acrylic monomer is preferably as small as possible.

  Examples of the polymerization method for synthesizing the base polymer include conventionally known solution polymerization method, emulsion polymerization method, bulk polymerization method, suspension polymerization method and the like, and among these, the polymerization of the copolymerization monomer component proceeds uniformly. Solution polymerization is preferred. Specific examples of the organic solvent for solution polymerization include ketone-based, ester-based, alcohol-based, and aromatic-based organic solvents. These organic solvents may be used alone or in combination. Among these, organic solvents having a boiling point of 60 to 120 ° C. are generally good solvents for the base polymer, such as toluene, ethyl acetate, isopropyl alcohol, benzene methyl cellosolve, ethyl cellosolve, acetone, and methyl ethyl ketone. Examples of the polymerization initiator include radical generators such as azobis type such as α, α′-azobisisobutylnitrile; organic peroxide type such as benzoperoxide. In the polymerization, a catalyst, a polymerization inhibitor or the like may be used as necessary.

  The (meth) acrylic polymer of the present embodiment includes a base polymer obtained as described above, a first functional group that reacts with a hydroxyl group introduced into the base polymer by a hydroxyl (meth) acrylic monomer, and radiation reactivity. It can be synthesized by reacting a radiation-reactive compound having a carbon-carbon double bond in the molecule and introducing a radiation-reactive carbon-carbon double bond in the side chain and / or terminal.

  Specific examples of the radiation-reactive compound include carboxyl group-containing monomers such as (meth) acrylic acid, cinnamic acid, itaconic acid, fumaric acid, and phthalic acid; and isocyanate groups such as isocyanate ethyl (meth) acrylate. Containing monomers; Epoxy group-containing monomers such as glycidyl (meth) acrylate; and amino group-containing monomers such as aminoethyl (meth) acrylate. These radiation reactive compounds may be used alone or in combination. Among these, an isocyanate group-containing monomer having an isocyanate group excellent in reactivity with a hydroxyl group as the first functional group is preferable.

  In the radiation-reactive compound, the molar amount of the hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer described above is the total mole of the first functional group of the radiation-reactive compound and the second functional group of the crosslinking agent. The amount of the residual hydroxyl group after the crosslinking reaction in the radiation-curable pressure-sensitive adhesive composition and the content of the radiation-reactive carbon-carbon double bond concentration within a predetermined range are used. Although it is necessary to consider the content of the hydroxyl group-containing (meth) acrylic monomer and the crosslinking agent, the preferable content range of the radiation-reactive compound is 7 to 15 parts by mass with respect to 100 parts by mass of the base polymer. More preferably, it is 7-12 mass parts. When there is too little content of a radiation reactive compound, a radiation reactive carbon-carbon double bond density | concentration will reduce and sclerosis | hardenability will fall. When there is too much content of a radiation reactive compound, while sclerosis | hardenability will be saturated, the hydroxyl group which reacts with a crosslinking agent will decrease, and the retention strength before hardening by a radiation will fall. Moreover, the unreacted low molecular weight component increases, and the adhesive strength before curing by radiation is reduced, or the contamination after curing by radiation is deteriorated. Furthermore, after stretching, interfacial peeling that causes the pressure-sensitive adhesive layer to peel from the substrate tends to occur, and it may be difficult to pick up a cut piece.

  Examples of the method for synthesizing the (meth) acrylic polymer include a method in which the base polymer and the radiation-reactive compound are subjected to a condensation reaction or an addition reaction while maintaining the radiation reactivity of the carbon-carbon double bond. In these reactions, it is preferable to use a polymerization inhibitor so that the radiation reactivity of the carbon-carbon double bond is maintained. As such a polymerization inhibitor, a quinone polymerization inhibitor such as hydroquinone monomethyl ether is preferable. The amount of the polymerization inhibitor is not particularly limited, but is usually 0.01 to 0.1 parts by mass with respect to the total amount of the base polymer and the radiation reactive compound.

  The weight average molecular weight of the (meth) acrylic polymer obtained as described above is preferably 300,000 to 2,000,000, more preferably 400,000 to 1,500,000. When the weight average molecular weight is less than 300,000, paste stains are likely to occur on the cut piece. On the other hand, if the weight average molecular weight is larger than 2 million, the radiation-curable pressure-sensitive adhesive composition may be gelated during synthesis and coating. In addition, in this specification, a weight average molecular weight means the polystyrene conversion weight average molecular weight by GPC (gel permeation chromatography) (solvent: tetrahydrofuran).

  The radiation-curable pressure-sensitive adhesive composition of the present embodiment has a (meth) acrylic polymer obtained as described above and a second crosslinking reaction with a hydroxyl group introduced into the base polymer by a hydroxyl (meth) acrylic monomer. Contains a crosslinking agent having a functional group in the molecule. By using such a crosslinking agent, a three-dimensional crosslinked structure can be formed, the cohesive force of the radiation-curable pressure-sensitive adhesive composition can be improved, and a radiation-curable pressure-sensitive adhesive composition with high holding power can be obtained. Can do.

  Specific examples of the crosslinking agent include, for example, polyisocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, melamine resin crosslinking agents, urea resin crosslinking agents, acid anhydride compound crosslinking agents, and polyamine crosslinking agents. Agents, carboxyl group-containing polymer-based crosslinking agents, and the like. These crosslinking agents may be used alone or in combination. Among these, a polyisocyanate crosslinking agent having an isocyanate group having excellent reactivity with a hydroxyl group as the second functional group is preferable.

  The content of the cross-linking agent is 0.3 to 2.7 parts by mass, preferably 0.3 to 1.3 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer, and the radiation reactive compound and Similarly, the molar amount of the hydroxyl group introduced into the base polymer by the hydroxyl (meth) acrylic monomer is equal to or greater than the total molar amount of the first functional group of the radiation-reactive compound and the second functional group of the crosslinking agent, and is radiation curable. The residual hydroxyl group concentration after the crosslinking reaction and the radiation-reactive carbon-carbon double bond concentration in the pressure-sensitive adhesive composition are used in a blending amount within a predetermined range. When there is too little content of a crosslinking agent, the retention strength before hardening by a radiation will fall. On the other hand, if the content of the cross-linking agent is too large, the radiation-curable pressure-sensitive adhesive composition of the present embodiment using a (meth) acrylic polymer having a certain amount of radiation-reactive carbon-carbon double bonds will not have hydroxyl groups and The amount of free crosslinking agent in the reaction increases, and the adhesive strength before curing with radiation decreases, and the contamination after curing with radiation deteriorates.

  The treatment for causing the (meth) acrylic polymer and the crosslinking agent to undergo a crosslinking reaction may be performed at room temperature, or may be performed under heating in order to promote the crosslinking reaction. When heating, the temperature is preferably 30 to 100 ° C. In order to prevent inactivation of the crosslinking agent due to moisture, the crosslinking treatment is preferably performed in a low humidity environment of 50% RH or less.

  The radiation-curable pressure-sensitive adhesive composition of the present embodiment may further contain a photopolymerization initiator when using ultraviolet rays as radiation. Specific examples of such photopolymerization initiators include benzoin alkyl ether initiators such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone and benzoylbenzoic acid. Benzophenone initiators such as 3,3′-dimethyl-4-methoxybenzophenone and polyvinylbenzophenone; 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- [ Aromatic ketone initiators such as-(methylthio) -phenyl] -2-morpholinopropane-1; aromatic ketal initiators such as benzyldimethyl ketal; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethyl Thioxanthone initiators such as thioxanthone, 2-isopropylthioxanthone, 2-dodecylthioxanthone, 2,4-dichlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone; benzyl such as benzyl Benzoin initiators such as benzoin; α-ketol compounds such as 2-methyl-2-hydroxypropiophenone; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; 1 Photoactive oxime compounds such as phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; camphorquinone compounds; halogenated ketone compounds: acyl phosphinoxide compounds; acyl phosphonate compounds Etc. These may be used alone or in combination. The blending amount of the photopolymerization initiator is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer.

  If the radiation-curable pressure-sensitive adhesive composition of the present embodiment contains the above (meth) acrylic polymer and a crosslinking agent, for the purpose of improving other properties, a tackifier, You may further contain well-known additives, such as anti-aging agent, a filler, a coloring agent, a flame retardant, an antistatic agent, a softening agent, a ultraviolet absorber, antioxidant, a plasticizer, and surfactant. However, it is preferable that the number of low molecular weight polyfunctional polymerizable compounds (for example, molecular weight or weight average molecular weight is 3,000 or less) such as polyfunctional monomers and polyfunctional oligomers having a radiation-reactive carbon-carbon double bond is as small as possible. More preferably, it is not substantially contained. When the radiation-curable pressure-sensitive adhesive composition of the present embodiment contains such a low molecular weight component, the adhesive force and holding force before curing by radiation are likely to be reduced, and the pickup property is likely to be deteriorated. In industrial products such as (meth) acrylic monomers and radiation-reactive compounds, low molecular weight polyfunctional polymerizable compounds may inevitably be mixed. The amount of such a low molecular weight polyfunctional polymerizable compound inevitably mixed is usually 1% by mass or less based on the total amount of the radiation curable pressure-sensitive adhesive composition.

  The dicing pressure-sensitive adhesive film of the present embodiment can be produced by coating the radiation curable pressure-sensitive adhesive composition on at least one surface of a substrate by a known method. Moreover, when using the separator mentioned later, after coating a radiation-curable adhesive composition on one surface of a separator, you may bond a base material to an adhesive layer. As the substrate, any substrate can be used without particular limitation as long as it has a property of transmitting radiation (X-rays, ultraviolet rays, electron beams, etc.) at least partially. Examples of such a base material include base materials such as plastic, metal, and paper, and among these, a plastic base material is preferable. Specific examples of such plastic substrates include polyolefin resins (low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer). Polymerized polypropylene, homopolypropylene, polybutene, polymethylpentene, etc.), ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester copolymer (random) Copolymer, alternating copolymer, etc.), ethylene-butene copolymer, ethylene-hexene copolymer, polyurethane resin, polyester resin (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphtha) Polyimide resin, polyamide resin, polyether ketone resin, polyether resin, polyether sulfone resin, polystyrene resin (polystyrene, etc.), polyvinyl chloride resin, polyvinylidene chloride resin, Groups consisting of constituent materials such as polyvinyl alcohol resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymers, polycarbonate resins, fluorine resins, silicone resins, cellulose resins, and cross-linked products of these resins Materials. These constituent materials may be used alone or in combination. The above-mentioned constituent materials may have a functional group as necessary. Further, a functional monomer or a modifying monomer may be grafted to the constituent material. Furthermore, the surface of the plastic substrate may be subjected to a known surface treatment method in order to improve the adhesion with an adjacent layer. Specific examples of such surface treatment include corona discharge treatment, ozone exposure treatment, high piezoelectric impact exposure treatment, and ionizing radiation treatment. In addition, the base material may be subjected to coating treatment with a primer, primer treatment, mat treatment, crosslinking treatment, and the like.

  The substrate may have a single layer form or may have a laminated form. Further, in the base material, as necessary, for example, known fillers, flame retardants, anti-aging agents, antistatic agents, softeners, ultraviolet absorbers, antioxidants, plasticizers, surfactants, etc. Additives may be included. Although the thickness of a base material is not specifically limited, Preferably it is 10-300 micrometers, More preferably, it is 30-200 micrometers.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 4 to 20 μm. If the thickness of the pressure-sensitive adhesive layer is 4 μm or more, a workpiece such as a semiconductor wafer can be reliably held by the pressure-sensitive adhesive film for dicing during dicing. In addition, since a workpiece such as a semiconductor wafer vibrates in the dicing process, chipping is likely to occur in a cut piece such as a semiconductor element if the vibration width is large. However, if the thickness of the pressure-sensitive adhesive layer is 20 μm or less, it is possible to prevent the vibration width of vibration generated during dicing from becoming too large.

  When a semiconductor wafer (silicon mirror wafer) is used as the workpiece, the adhesive force of the adhesive layer on the semiconductor wafer (silicon mirror wafer) before curing by radiation (peeling angle: 180 °, tensile speed: 300 mm / min, temperature) : 23 ± 3 ° C.) is preferably 0.5 (N / 10 mm width) or more, and more preferably 1.0 (N / 10 mm width) or more. If the adhesive force before curing by radiation is 0.5 (N / 10 mm width) or more, the detachment scattering of the semiconductor element in the dicing process can be sufficiently suppressed or prevented. The adhesive strength (peeling angle: 180 °, tensile speed: 300 mm / min, temperature: 23 ± 3 ° C.) after curing of the adhesive layer to the semiconductor wafer (silicon mirror wafer) by radiation is preferably 0.15 (N / 10 mm width) or less, more preferably less than 0.10 (N / 10 mm width). If the pressure-sensitive adhesive layer has such a low adhesive strength after being cured by radiation, pick-up failure is small and adhesive residue (remaining pressure-sensitive adhesive component) can also be reduced.

  Also, the adhesive strength of the adhesive layer to the SUS metal member before curing by radiation (test plate: SUS304 (BA) plate specified in JIS G 4305, peeling angle: 180 °, tensile speed: 300 mm / min, temperature) : 23 ± 3 ° C.) is preferably 0.4 (N / 10 mm width) or more. If the adhesive strength before curing by radiation is 0.4 (N / 10mm width) or more, the ring frame can be firmly fixed to the adhesive layer, and the detachment scattering of the semiconductor element in the dicing process is sufficiently suppressed. Or it can be prevented.

  Further, holding force of the adhesive layer before curing by radiation (test plate: SUS304 (BA) plate defined in JIS G 4305, bonding area: 25 mm × 25 mm, load: 1.0 kg, temperature: 60 ° C., humidity: 50% RH, retention time: 1 week) is the amount of deviation when measured according to JIS Z 0237, and is preferably less than 0.1 mm. If the holding power before curing by radiation is less than 0.1 mm, vibration of the semiconductor element in the dicing process can be sufficiently suppressed, and chipping can be further reduced.

  FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the dicing adhesive film of the present embodiment. As shown in FIG. 1, the adhesive film 1 for dicing of this Embodiment has the structure by which the adhesive layer 3 containing said radiation curable adhesive composition was formed on one surface of the base material 2. As shown in FIG. ing. Moreover, as shown in FIG. 1, the separator 4 may be provided on the adhesive layer 3 as needed. The separator 4 is not particularly limited, and a known separator can be used. Specific examples of the constituent material of the separator 4 include papers; synthetic resins such as polyethylene, polypropylene, and polyethylene terephthalate. Moreover, in order to improve the peelability of the adhesive layer 3, the surface of the separator 4 may be subjected to treatments such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary. The thickness of the separator 4 is not particularly limited, but is usually 10 to 200 μm. The pressure-sensitive adhesive layer 3 may be a single layer or two or more layers. In FIG. 1, the pressure-sensitive adhesive layer 3 is provided only on one side of the base material 2, but the pressure-sensitive adhesive layer 3 may be provided on both sides of the base material 2. Moreover, although not shown in figure, according to the usage form, another adhesive layer, a mold release process layer, etc. may be formed on the other surface of the base material 2 instead of the separator 4. Specific examples of the pressure-sensitive adhesive composition for forming other pressure-sensitive adhesive layers include acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, and polyamides. A pressure-sensitive adhesive composition containing a known pressure-sensitive adhesive such as a pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a vinyl alkyl ether-based pressure-sensitive adhesive, or a fluorine-based pressure-sensitive adhesive can be used. The pressure-sensitive adhesive composition formed on the other surface of the substrate may contain various additives, a radiation curable component, a foaming agent, and the like as necessary. Specific examples of the release treatment agent (release agent) for forming the release treatment layer include, for example, a silicone release treatment agent, a long-chain alkyl release treatment agent, and a fluorine release treatment. A known release treatment agent such as an agent can be used. The dicing adhesive film may have a form wound in a roll shape or a form in which wide sheets are laminated. Further, it may be in the form of a sheet or tape cut into a predetermined size.

  The dicing adhesive film of this embodiment can be used when a workpiece is diced to produce a cut piece. Specific examples of such a workpiece include a semiconductor wafer, a semiconductor package, glass, and ceramics. These workpieces are composed of compounds such as silicon compounds, germanium compounds, and gallium-arsenic compounds, and active silicon atoms (Si) in an unoxidized state are exposed on the exposed surface by back grinding or the like. ), There are many unoxidized active atoms such as unoxidized active germanium atoms (Ge) and unoxidized active gallium atoms (Ga). Therefore, when a dicing adhesive film is affixed to the workpiece in order to dice the workpiece having such active atoms, the polar portion of the (meth) acrylic polymer contained as a main component in the adhesive layer Bonding with active atoms shows high adhesive strength even after curing by radiation, making it difficult to separate the cut piece from the dicing adhesive film. However, according to the adhesive film for dicing of the present embodiment, even when the adhesive film for dicing is attached to the workpiece having the active surface, when the cut piece is peeled off from the adhesive film for dicing, Regardless, the adhesive force to the active surface can be sufficiently reduced by irradiation with radiation, and the cut piece can be easily peeled off.

  In the present embodiment, as a method of manufacturing a cut piece by dicing a workpiece, a mounting step of sticking a dicing adhesive film on one surface of the workpiece and a workpiece on which a dicing adhesive film is stuck From the dicing adhesive film for dicing, in which the adhesive force of the adhesive layer is reduced by irradiating the adhesive layer applied to the cut piece with radiation, and the dicing step of cutting the adhesive piece into pieces. A production method having at least a pick-up step for picking up the cut piece can be suitably used.

  In the mounting process in which an adhesive film for dicing is attached to one surface of a workpiece, one surface of the ring frame, one surface of the workpiece such as a semiconductor wafer, and one surface of the pressure-sensitive adhesive layer are usually overlapped. By pressing this with a known pressing means such as a press roll, a dicing adhesive film is attached to the workpiece. Further, in a pressurizable container (for example, an autoclave), the work piece and the dicing adhesive film are overlapped in the same manner as described above, and the inside of the container is pressurized to dicing the work piece. An adhesive film may be affixed. Furthermore, a dicing adhesive film may be attached to the workpiece in the same manner as in the case of attachment by pressurization in a reduced pressure chamber (vacuum chamber).

  Next, in the dicing step, a workpiece such as a semiconductor wafer attached to the dicing adhesive film is diced by a dicing means such as a blade to produce a cut piece of the workpiece. In such a dicing process, a blade that rotates at high speed while supplying cleaning water to a workpiece such as a semiconductor wafer to which a pressure-sensitive adhesive film for dicing is usually attached in order to prevent the removal of frictional heat and adhesion of cutting waste. The workpiece is cut into a predetermined size. For this reason, although a cutting piece vibrates with a cutting blade and chipping is likely to occur, the radiation-curable pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer of the dicing pressure-sensitive adhesive film of the present embodiment has a high pressure-sensitive adhesive force and a high holding power. Therefore, it is possible to reduce the detachment scattering of the cut piece from the dicing adhesive film and to reduce chipping. The dicing apparatus is not particularly limited, and a conventionally known apparatus can be used. In addition, a washing | cleaning process, an expanding process, etc. may be performed after a dicing process as needed.

  In the pickup step, the adhesive layer of the dicing adhesive film is irradiated with radiation to reduce the adhesive strength of the adhesive layer, and then the cut piece is picked up from the dicing adhesive film. Examples of radiation include X-rays, electron beams, and ultraviolet rays. Among these, ultraviolet rays are preferable. Various conditions such as irradiation intensity and irradiation time when irradiating with radiation are not particularly limited, and can be set as appropriate. The pickup method is not particularly limited, and various conventionally known pickup methods can be employed. For example, there is a method in which individual cut pieces are pushed up by a needle from the dicing adhesive film side, and the pushed up cut pieces are picked up by a pickup device. Since the adhesive film for dicing according to the present embodiment can sufficiently reduce the adhesive force by irradiation with radiation, even in the case of using a workpiece having an active surface, the above pick-up process can be easily performed. The cut piece can be peeled from the dicing adhesive film, and adhesion of the adhesive component to the cut piece after peeling can be reduced.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In the following description, “part” means “part by mass”.

<Synthesis of (meth) acrylic polymer>
As a copolymerization monomer component, ethyl acrylate having a linear alkyl group having 2 carbon atoms [solubility parameter (SP value, the same applies hereinafter): 10.2 (cal / cm ³ ) ^1/2 , molecular weight: 100.12], 2-ethylhexyl acrylate having a branched alkyl group having 8 carbon atoms [SP value: 9.2 (cal / cm ³ ) ^1/2 , molecular weight: 184.28], acrylic acid having a linear alkyl group having 18 carbon atoms Octadecyl [SP value: 9.0 (cal / cm ³ ) ^1/2 , molecular weight: 324.54], and 2-hydroxyethyl acrylate having a hydroxyl group [SP value: 13.3 (cal / cm ³ ) ^{1 / 2} , molecular weight: 116.12]. These copolymerization monomer components were mixed in the respective compounding amounts shown in Tables 1 and 2, and each base polymer was synthesized by solution radical polymerization (solvent: ethyl acetate). In the polymerization, the reaction of the copolymerization monomer component was traced by GPC, and the polymerization was terminated when the copolymerization monomer component disappeared.

  Next, for each base polymer, 2-isocyanate ethyl methacrylate having an isocyanate group and a radiation-reactive carbon-carbon double bond as a radiation-reactive compound (first functional group: isocyanate group, number of first functional groups: 1) (Mole) / molecule, molecular weight: 155.15) were reacted in the respective compounding amounts shown in Tables 1 and 2, to synthesize each (meth) acrylic polymer. In the above reaction, 0.05 part of hydroquinone monomethyl ether was used as a polymerization inhibitor. When the weight average molecular weight of each synthesized (meth) acrylic polymer was measured by GPC (solvent: tetrahydrofuran), it was 500,000 to 800,000.

<Preparation of adhesive film for dicing>
Each (meth) acrylic polymer obtained as described above, and a polyisocyanate compound having a blending amount shown in Tables 1 and 2 as a crosslinking agent (trade name: Coronate L, second functional group: manufactured by Nippon Polyurethane Co., Ltd.) Isocyanate group, number of second functional groups: 3/1 molecule, molecular weight: 656.64) and 1-hydroxycyclohexyl phenyl ketone as photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name: Irgacure-184) 0 .5 parts were mixed to prepare each radiation-curable pressure-sensitive adhesive composition. For Comparative Example 7, a radiation curable pressure-sensitive adhesive composition in which trimethylolpropane triacrylate (functional group: 3/1 molecule, molecular weight: 296.32) was further added as a polyfunctional monomer in the amount shown in Table 2. A product was prepared.

  Next, each radiation-curable pressure-sensitive adhesive composition obtained as described above was applied on a polyethylene terephthalate separator (thickness: 38 μm) so as to have the thicknesses shown in Tables 1 and 2, and a pressure-sensitive adhesive layer. After being formed, it was dried by heating in an environment of 100 ° C. and 50% RH for 3 minutes. Thereafter, a polyolefin film (thickness: 100 μm) having a corona discharge treatment on one side was bonded to the pressure-sensitive adhesive layer. The bonded sample was stored in a constant temperature bath at 40 ° C. and 50% RH for 72 hours, subjected to crosslinking treatment, and each pressure-sensitive adhesive film for dicing was produced.

  The following evaluation was performed using each dicing adhesive film produced as described above. Tables 1 and 2 show the composition of each radiation-curable pressure-sensitive adhesive composition, the solubility parameter of the base polymer, the difference between the molar amount of the hydroxyl group of the base polymer and the total molar amount of the first functional group and the second functional group, the residual hydroxyl group concentration , Radiation reactive carbon-carbon double bond concentration, and evaluation results are also shown. The radiation-reactive carbon-carbon double bond concentration in the radiation-curable pressure-sensitive adhesive composition of Comparative Example 7 is the total amount of radiation-reactive carbon-carbon double bonds that the radiation-reactive compound and the polyfunctional monomer have. Based on the value.

[Evaluation]
(Adhesion to SUS before curing by radiation)
A measurement sample was prepared by laminating an adhesive film for dicing cut into 25 mm-wide strips on a SUS304 (BA) plate in an atmosphere at 23 ° C., and allowing this to stand for 30 minutes in a room temperature atmosphere. The adhesive strength of this measurement sample was measured, and the adhesive strength before curing was evaluated according to the following criteria. The adhesive strength was measured at a peeling angle of 180 °, a peeling speed of 300 mm / min, and a temperature of 23 ± 3 ° C.
○: The measured value of adhesive strength is 0.4 N / 10 mm or more. Δ: The measured value of adhesive strength is less than 0.4 N / 10 mm. X: The adhesive strength cannot be measured due to cohesive failure.

(Adhesion to semiconductor wafer before curing by radiation)
A measurement sample was prepared by bonding a dicing adhesive film cut into a 25 mm width strip to a 5-inch silicon mirror wafer immediately after mirror polishing in an atmosphere of 23 ° C., and allowing this to stand at room temperature for 30 minutes. Produced. The adhesive strength of this measurement sample was measured, and the adhesive strength before curing was evaluated according to the following criteria. The adhesive strength was measured at a peeling angle of 180 °, a peeling speed of 300 mm / min, and a temperature of 23 ± 3 ° C.
○: The measured value of adhesive strength is 1.0 N / 10 mm or more. Δ: The measured value of adhesive strength is 0.5 N / 10 mm or more and less than 1.0 N / 10 mm. X: The measured value of adhesive strength is 0.5 N / Less than 10mm or cohesive failure cannot be measured

(Retention force before curing by radiation)
A polyester film (19 μm thick) was lined on a dicing adhesive film cut into a 25 mm strip, and then the dicing adhesive film was attached to a SUS304 (BA) plate in an atmosphere of 23 ° C. (bonding area: 25 mm x 25 mm). The bonded sample was allowed to stand for 30 minutes in a room temperature atmosphere to prepare a measurement sample. The amount of deviation after applying a load of 1.0 kg for one week in an environment of a temperature of 60 ° C. and a humidity of 50% RH was measured, and the holding power was evaluated according to the following criteria.
○: After one week, the amount of deviation is less than 0.1 mm. ×: After one week, the amount of deviation is 0.1 mm or more, or the film falls.

(Adhesion to semiconductor wafer after curing by radiation)
A measurement sample similar to the measurement sample used in the measurement of the adhesive strength before curing by radiation was prepared. The measurement sample was irradiated with ultraviolet rays (irradiation intensity: 300 mJ / cm ² ) from the substrate side of the dicing adhesive film, and the adhesive strength after irradiation was measured in the same manner as the adhesive strength before curing with the above-mentioned radiation. The adhesive strength after curing was evaluated on the basis of
○: The measured value of adhesive force is less than 0.1 N / 10 mm. Δ: The measured value of adhesive force is 0.1 N / 10 mm or more and 0.15 N / 10 mm or less. X: The measured value of adhesive force is 0.15 N / Over 10mm

(Pickup property)
A 5-inch silicon mirror wafer having a thickness of 100 μm was mirror-polished, and then a dicing adhesive film was immediately attached to the polished surface in an atmosphere at 23 ° C. The wafer was fully cut into a size of 10 mm × 10 mm while supplying cleaning water to the wafer with the adhesive film attached thereto.
Next, after irradiating ultraviolet rays (irradiation intensity: 300 mJ / cm ² ) from the base material side of the dicing adhesive film, one diced semiconductor element is formed to a height of 500 μm with five needles from the base material side. The semiconductor element pushed up and picked up using a collet was picked up. The force (pickup force) required for picking up this semiconductor element was measured, the average value of the pick-up force of 10 semiconductor elements was determined, and the pickup property was evaluated according to the following criteria.
○: The average value of the pickup force is 1.5N or less △: The average value of the pickup force is more than 1.5N, 2.0N or less ×: The average value of the pickup force is more than 2.0N

(Chipping)
A 5-inch silicon mirror wafer having a thickness of 100 μm was mirror-polished, and then a dicing adhesive film was immediately bonded to the polished surface in an atmosphere at 23 ° C. The wafer was fully cut into a size of 10 mm × 10 mm while supplying cleaning water to the wafer with the adhesive film attached thereto.
Next, ultraviolet rays (irradiation intensity: 300 mJ / cm ² ) were irradiated from the substrate side of the adhesive film for dicing and expanded, and then the semiconductor element was peeled off from the adhesive film and picked up. Five were arbitrarily selected from the picked-up semiconductor elements, the back surface chipping of each side was observed with a microscope, and chipping was evaluated according to the following criteria.
○: Maximum chipping size of all semiconductor elements is 15 μm or less ×: Maximum chipping size of at least one semiconductor element exceeds 15 μm

(Contamination)
In a clean room (cleanness: class 100), the adhesive film for dicing is bonded to a 6-inch silicon mirror wafer, left standing at room temperature for 30 minutes, and then irradiated with ultraviolet rays (irradiation intensity) from the substrate side of the adhesive film for dicing. : 300 mJ / cm ² ). This sample was stored for 30 days in an environment of 23 ° C. and 50% RH, and then the dicing adhesive film was peeled from the wafer, and the wafer surface after peeling was subjected to laser surface inspection equipment (LS-6000, manufactured by Hitachi High-Technology Corporation). ) And evaluated the contamination by the following criteria.
○: Total number of contaminants is less than 2,000 ×: Total number of contaminants is 2,000 or more

  As shown in the above table, the pressure-sensitive adhesive film for dancing using the radiation-curable pressure-sensitive adhesive composition of the examples has high adhesive strength and high holding power before curing with radiation and low adhesive strength after curing with radiation. It turns out that it has. For this reason, when these adhesive films for dicing are used, it turns out that there is little generation | occurrence | production of pick-up defect and there are few glue stains on a cut piece. Furthermore, it can be seen that the chipping of the obtained semiconductor element is also small.

  In contrast, an adhesive film for dancing using a radiation curable adhesive composition containing a (meth) acrylic polymer obtained from a base polymer having a solubility parameter that is too high or too low is high even after curing with radiation. It can be seen that it has adhesive strength and is therefore poor in pick-up performance. This is presumably because if the solubility parameter of the base polymer is too high, the polar site of the (meth) acrylic polymer is not sufficiently concealed by the alkyl group, and the polar site and the active atom are likely to contact each other. On the other hand, when a base polymer having a solubility parameter that is too low is used, the amount of hydroxyl groups introduced into the base polymer decreases, and the concentration of radiation-reactive carbon-carbon double bonds that can be introduced into the (meth) acrylic polymer decreases. it is conceivable that.

  Moreover, it turns out that the adhesive film for dancing using the radiation-curable pressure-sensitive adhesive composition having a residual hydroxyl group concentration that is too high has a high adhesive force even after curing by radiation, and is therefore poor in pick-up property. This makes it easier for the semiconductor wafer having an active surface and the remaining hydroxyl group to bond, and as a result, even if the (meth) acrylic polymer has a certain amount of radiation-reactive carbon-carbon double bonds, the adhesive strength is high. It is thought that it is difficult to decrease.

  Further, it can be seen that the adhesive film for dancing using the radiation curable pressure-sensitive adhesive composition having too little content of the crosslinking agent has low holding power and chipping occurs. On the other hand, even if the concentration of the radiation-reactive carbon-carbon double bond is within a certain range, if the content of the crosslinking agent is too large, the first amount of the radiation-reactive compound is larger than the molar amount of the hydroxyl group introduced into the base polymer. The total molar amount of the functional group and the second functional group of the crosslinking agent is increased, and the adhesive force before curing by radiation is reduced, and the contamination is deteriorated. Further, even if the content of the crosslinking agent is within a certain range, in order to improve curability, the first functional group of the radiation-reactive compound and the number of the crosslinking agent are higher than the molar amount of the hydroxyl group introduced into the base polymer. When a radiation-reactive carbon-carbon double bond is introduced into a (meth) acrylic polymer to such an extent that the total molar amount of bifunctional groups increases, not only the retention before curing by radiation is reduced, but also the contamination property to degrade.

  And when a polyfunctional monomer is used and the radiation-reactive carbon-carbon double bond concentration in the radiation-curable pressure-sensitive adhesive composition is increased, the adhesive strength after curing by radiation is lowered, but the pick-up property is rather. It can be seen that there is a slight decrease, and that the adhesive force and holding force before curing by radiation are reduced. This is presumably because the use of the low molecular weight polyfunctional polymerizable compound softened the radiation curable pressure-sensitive adhesive composition and inhibited the crosslinking reaction between the (meth) acrylic polymer and the crosslinking agent.

DESCRIPTION OF SYMBOLS 1 Adhesive film for dicing 2 Base material 3 Adhesive layer 4 Separator

Claims (4)

A dicing pressure-sensitive adhesive film comprising a base material and a pressure-sensitive adhesive layer containing a radiation-curable pressure-sensitive adhesive composition on the base material,
The radiation-curable pressure-sensitive adhesive composition has at least an alkyl group-containing (meth) acrylic monomer and a hydroxyl group-containing (meth) acrylic monomer as a copolymerization monomer component, and 9.6 (cal / cm ³ ) ^{1 /} A base polymer having a solubility parameter of ² or more and 10.0 (cal / cm ³ ) ^1/2 or less, a first functional group that reacts with a hydroxyl group introduced into the base polymer by the hydroxyl group-containing (meth) acrylic monomer, and With respect to 100 parts by weight of the (meth) acrylic polymer obtained by reacting with a radiation reactive compound having a radiation reactive carbon-carbon double bond in the molecule, and 100 parts by weight of the (meth) acrylic polymer, the hydroxyl group Containing 0.3 to 2.7 parts by mass of a crosslinking agent having a second functional group that undergoes a crosslinking reaction in the molecule,
The hydroxyl group-containing (meth) acrylic monomer, the radiation-reactive compound, and the crosslinking agent have a molar amount of a hydroxyl group introduced into the base polymer by the hydroxyl-containing (meth) acrylic monomer. More than the total molar amount of the first functional group and the second functional group of the crosslinking agent, the residual hydroxyl group concentration after the crosslinking reaction is 0.08 mmol or less per 1 g of the radiation curable pressure-sensitive adhesive composition, and the radiation reactive compound The concentration of the radiation-reactive carbon-carbon double bond introduced into the (meth) acrylic polymer by 0.45 mmol or more and 0.84 mmol or less per 1 g of the radiation-curable pressure-sensitive adhesive composition. Dicing adhesive film.   The pressure-sensitive adhesive film for dicing according to claim 1, wherein the radiation-curable pressure-sensitive adhesive composition contains substantially no low molecular weight polyfunctional polymerizable compound. Affixing the adhesive film for dicing according to claim 1 or 2 on one surface of the workpiece,
The workpiece to which the adhesive film for dicing is attached is cut and separated into cut pieces,
Radiation is applied to the adhesive layer attached to the cut piece to reduce the adhesive strength of the adhesive layer,
The manufacturing method of the cut piece which picks up the said cut piece from the adhesive film for dicing which reduced the said adhesive force.   The method for manufacturing a cut piece according to claim 3, wherein the workpiece is a semiconductor wafer having an active surface.

Images