JP6759218B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet.

In recent years, chip size package (CSP) technology has been attracting attention as a mounting technology. Among these techniques, a chip-only package typified by a wafer level package (WLP) that does not use a substrate has attracted particular attention in terms of miniaturization and high integration.
In such a method for manufacturing a WLP, it is conventionally necessary to fix a chip fixed on a substrate on another support. Therefore, for example, Patent Document 1 describes an adhesive tape that is attached and used when a substrateless semiconductor chip that does not use a metal lead frame is resin-sealed. Patent Document 1, an adhesive tape having a glass transition temperature one surface of the substrate layer of greater than 180 ° C., or, on both sides, the elastic modulus at 180 ° C. is provided 1.0 × 10 5 ^Pa or more pressure-sensitive adhesive layer Is described.

Japanese Unexamined Patent Publication No. 2012-062372

For example, when the pressure-sensitive adhesive sheet as described in Patent Document 1 is used, the circuit surface of the semiconductor element is fixed to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. On the circuit surface of the semiconductor element, there is a stepped portion such as a dicing line on the peripheral portion of the semiconductor element. Then, when sealing the semiconductor element on the pressure-sensitive adhesive sheet, the sealing resin fills the gap between the step portion and the pressure-sensitive adhesive layer.
However, it was found that depending on the type of the sealing resin, the sealing resin could not fill the gap between the stepped portion and the pressure-sensitive adhesive layer, and a gap was formed. If such a gap is formed, the smoothness of the circuit surface of the semiconductor element becomes insufficient, and there is a possibility that a problem may occur when forming a pattern on the circuit surface. Therefore, the pressure-sensitive adhesive sheet is required to have a property that the sealing resin easily embeds a gap between the step portion and the pressure-sensitive adhesive layer (hereinafter, may be referred to as filling property).

An object of the present invention is to provide a pressure-sensitive adhesive sheet having excellent filling properties when sealing a semiconductor element on the pressure-sensitive adhesive sheet.

According to one aspect of the present invention, it is a pressure-sensitive adhesive sheet used for sealing a semiconductor element on a pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet includes a base material and a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is provided. surface free energy 10 mJ / ^{m 2} or more 22 mJ / ^{m 2} or less is the pressure-sensitive adhesive sheet is provided.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the contact angle of 1-bromonaphthalene with respect to the pressure-sensitive adhesive layer is preferably 65 ° or more.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the storage elastic modulus of the base material at 100 ° C. is preferably 1 × 10 ⁷ Pa or more.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the pressure-sensitive adhesive layer preferably contains an acrylic pressure-sensitive adhesive composition or a silicone-based pressure-sensitive adhesive composition.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the acrylic pressure-sensitive adhesive composition preferably contains an acrylic copolymer containing 2-ethylhexyl acrylate as a main monomer.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the silicone-based pressure-sensitive adhesive composition preferably contains an addition polymerization type silicone resin.

According to the present invention, it is possible to provide an adhesive sheet having excellent filling properties when sealing a semiconductor element on the adhesive sheet.

It is sectional drawing of the adhesive sheet which concerns on embodiment of this invention. It is a figure explaining a part of the manufacturing process of the semiconductor device using the adhesive sheet which concerns on embodiment of this invention. It is a figure explaining a part of the manufacturing process of the semiconductor device using the adhesive sheet which concerns on embodiment of this invention. It is a figure explaining a part of the manufacturing process of the semiconductor device using the adhesive sheet which concerns on embodiment of this invention. It is a figure explaining a part of the manufacturing process of the semiconductor device using the adhesive sheet which concerns on embodiment of this invention. It is a figure explaining a part of the manufacturing process of the semiconductor device using the adhesive sheet which concerns on embodiment of this invention. It is sectional drawing which shows the semiconductor element after the sealing process which concerns on embodiment of this invention.

[Embodiment]
(Adhesive sheet)
FIG. 1 shows a schematic cross-sectional view of the pressure-sensitive adhesive sheet 10 of the present embodiment.
The pressure-sensitive adhesive sheet 10 has a base material 11 and a pressure-sensitive adhesive layer 12. As shown in FIG. 1, a release sheet RL is laminated on the pressure-sensitive adhesive layer 12.
The base material 11 has a first base material surface 11a and a second base material surface 11b opposite to the first base material surface 11a. The shape of the adhesive sheet 10 can be any shape such as a sheet shape, a tape shape, and a label shape.

(Base material)
The base material 11 is a member that supports the pressure-sensitive adhesive layer 12.
As the base material 11, for example, a sheet material such as a synthetic resin film can be used. Examples of the synthetic resin film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film. , Polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, And fluororesin film and the like. In addition, examples of the base material 11 include these crosslinked films and laminated films.

The base material 11 preferably contains a polyester-based resin, and more preferably is made of a material containing the polyester-based resin as a main component. In the present specification, the material containing the polyester resin as a main component means that the ratio of the mass of the polyester resin to the total mass of the material constituting the base material is 50% by mass or more. The polyester-based resin may be, for example, any resin selected from the group consisting of polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate, polybutylene naphthalate resin, and copolymer resins of these resins. Preferably, a polyethylene terephthalate resin is more preferable.
As the base material 11, polyethylene terephthalate film and polyethylene naphthalate are preferable, and polyethylene terephthalate film is more preferable. The oligomer contained in the polyester film is derived from a polyester-forming monomer, dimer, trimer and the like.

The lower limit of the storage elastic modulus of the base material 11 at 100 ° C. is preferably 1 × 10 ⁷ Pa or more, and more preferably 1 × 10 ⁸ Pa or more, from the viewpoint of dimensional stability during processing. The upper limit of the storage elastic modulus of the base material 11 at 100 ° C. is preferably 1 × 10 ¹² Pa or less from the viewpoint of processability. In the present specification, the storage elastic modulus is a value measured at a frequency of 1 Hz by a torsional shear method using a dynamic viscoelasticity measuring device.
The base material to be measured is cut into a width of 5 mm and a length of 20 mm, and a viscoelasticity measuring device (DMAQ800 manufactured by TA Instruments) is used to measure the stored viscoelasticity at a frequency of 11 Hz and a tensile mode at 100 ° C. did.

The first base material surface 11a may be subjected to at least one surface treatment such as a primer treatment, a corona treatment, and a plasma treatment in order to enhance the adhesion to the pressure-sensitive adhesive layer 12. The first base material surface 11a of the base material 11 may be coated with an adhesive and subjected to an adhesive treatment. Examples of the pressure-sensitive adhesive used for the pressure-sensitive adhesive treatment of the base material include acrylic-based, rubber-based, silicone-based, and urethane-based pressure-sensitive adhesives.

The thickness of the base material 11 is preferably 10 μm or more and 500 μm or less, more preferably 15 μm or more and 300 μm or less, and further preferably 20 μm or more and 250 μm or less.

(Adhesive layer)
In this embodiment, it is necessary that the surface free energy of the pressure-sensitive adhesive layer 12 is 10 mJ / ^{m 2} or more 22 mJ / ^{m 2} or less. If the surface free energy of the pressure-sensitive adhesive layer 12 is 10 mJ / m ² or more 22 mJ / m ² or less, excellent semiconductor device on the adhesive sheet 10 to the filling of the time of sealing, sealing the semiconductor elements on the adhesive sheet 10 At the time of stopping, the sealing resin can fill the gap between the stepped portion of the semiconductor element and the pressure-sensitive adhesive layer.
Further, the surface free energy of the pressure-sensitive adhesive layer is more preferably 12 mJ / m ² or more and 21.5 mJ / m ² or less.

The surface free energy of the pressure-sensitive adhesive layer 12 can be measured by the following method. Specifically, first, the contact angle of water, diiodomethane, and 1-bromonaphthalene with respect to the pressure-sensitive adhesive layer 12 is measured using a contact angle measuring device (“DM701” manufactured by Kyowa Interface Science Co., Ltd.). The amount of each droplet was 2 μL. Then, the surface free energy can be calculated from these measured values by the Kitazaki-Hata method.

In the present embodiment, from the viewpoint of filling property, the contact angle of 1-bromonaphthalene is preferably 65 ° or more, preferably 67 ° or more, and more preferably 68 ° or more.

Examples of the method for adjusting the values of the surface free energy and the contact angle include the following methods. For example, the values of the surface free energy and the contact angle can be adjusted by changing the composition of the pressure-sensitive adhesive composition used in the pressure-sensitive adhesive layer 12.

The pressure-sensitive adhesive layer 12 according to this embodiment contains a pressure-sensitive adhesive composition. The pressure-sensitive adhesive contained in this pressure-sensitive adhesive composition is not particularly limited, and various types of pressure-sensitive adhesives can be applied to the pressure-sensitive adhesive layer 12. Examples of the pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer 12 include rubber-based, acrylic-based, silicone-based, polyester-based, and urethane-based adhesives. The type of adhesive is selected in consideration of the intended use, the type of adherend to be adhered, and the like. The pressure-sensitive adhesive layer 12 preferably contains an acrylic pressure-sensitive adhesive composition or a silicone-based pressure-sensitive adhesive composition.

-Acrylic Adhesive Composition When the pressure-sensitive adhesive layer 12 contains an acrylic pressure-sensitive adhesive composition, the acrylic pressure-sensitive adhesive composition preferably contains an acrylic copolymer containing 2-ethylhexyl acrylate as a main monomer. ..
When the pressure-sensitive adhesive layer 12 contains an acrylic pressure-sensitive adhesive composition, it preferably contains an acrylic-based copolymer and a pressure-sensitive adhesive. The acrylic copolymer is preferably a copolymer containing 2-ethylhexyl acrylate as a main monomer. The tacky aid preferably contains a rubber-based material having a reactive group as a main component.

In the present specification, when 2-ethylhexyl acrylate is the main monomer, the ratio of the mass of the copolymer component derived from 2-ethylhexyl acrylate to the total mass of the acrylic copolymer is 50% by mass or more. Means. In the present embodiment, the proportion of the copolymer component derived from 2-ethylhexyl acrylate in the acrylic copolymer is preferably 50% by mass or more and 95% by mass or less, and 60% by mass or more and 95% by mass or less. It is more preferably 80% by mass or more and 95% by mass or less, and further preferably 85% by mass or more and 93% by mass or less. When the proportion of the copolymer component derived from 2-ethylhexyl acrylate is 50% by mass or more, the adhesive strength does not become too high after heating, and the adhesive sheet is more easily peeled from the adherend, and 80% by mass or more. If so, it becomes easier to peel off. If the proportion of the copolymer component derived from 2-ethylhexyl acrylate is 95% by mass or less, the initial adhesion is insufficient and the base material is deformed during heating, or the adhesive sheet is peeled off from the adherend due to the deformation. You can prevent it from happening.

The type and number of copolymer components other than 2-ethylhexyl acrylate in the acrylic copolymer are not particularly limited. For example, as the second copolymer component, a functional group-containing monomer having a reactive functional group is preferable. When a cross-linking agent described later is used, the reactive functional group of the second copolymer component is preferably a functional group capable of reacting with the cross-linking agent. The reactive functional group is preferably at least one substituent selected from the group consisting of, for example, a carboxyl group, a hydroxyl group, an amino group, a substituted amino group, and an epoxy group, and at least one of the carboxyl group and the hydroxyl group. It is more preferably a substituent, and even more preferably a carboxyl group.

Examples of the monomer having a carboxyl group (monomer containing a carboxyl group) include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among the carboxyl group-containing monomers, acrylic acid is preferable from the viewpoint of reactivity and copolymerizability. The carboxyl group-containing monomer may be used alone or in combination of two or more.

Examples of the monomer having a hydroxyl group (hydroxyl-containing monomer) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2 (meth) acrylate. Examples thereof include (meth) acrylate hydroxyalkyl esters such as −hydroxybutyl, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Among the hydroxyl group-containing monomers, 2-hydroxyethyl (meth) acrylate is preferable from the viewpoint of hydroxyl group reactivity and copolymerizability. The hydroxyl group-containing monomer may be used alone or in combination of two or more. In addition, "(meth) acrylic acid" in this specification is a notation used when expressing both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.

Examples of the acrylic acid ester having an epoxy group include glycidyl acrylate and glycidyl methacrylate.

Examples of other copolymer components in the acrylic copolymer include (meth) acrylic acid alkyl esters having 2 to 20 carbon atoms in the alkyl group. Examples of the (meth) acrylic acid alkyl ester include ethyl (meth) acrylic acid, propyl (meth) acrylic acid, n-butyl (meth) acrylic acid, n-pentyl (meth) acrylic acid, and n (meth) acrylic acid. -Hexyl, 2-ethylhexyl methacrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, (meth) ) Stearyl acrylate and the like can be mentioned. Among these (meth) acrylic acid alkyl esters, (meth) acrylic acid esters having 2 to 4 carbon atoms in the alkyl group are preferable, and n-butyl (meth) acrylate is more preferable from the viewpoint of further improving the adhesiveness. preferable. The (meth) acrylic acid alkyl ester may be used alone or in combination of two or more.

Other copolymer components in the acrylic copolymer include, for example, an alkoxyalkyl group-containing (meth) acrylic acid ester, a (meth) acrylic acid ester having an aliphatic ring, and a (meth) acrylic acid having an aromatic ring. Copolymer components derived from at least one monomer selected from the group consisting of esters, non-crosslinkable acrylamides, non-crosslinkable tertiary amino group (meth) acrylic acid esters, vinyl acetate, and styrene. Can be mentioned.
Examples of the alkoxyalkyl group-containing (meth) acrylic acid ester include methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, and ethoxyethyl (meth) acrylate. ..
Examples of the (meth) acrylic acid ester having an aliphatic ring include cyclohexyl (meth) acrylic acid.
Examples of the (meth) acrylic acid ester having an aromatic ring include phenyl (meth) acrylic acid.
Examples of non-crosslinkable acrylamide include acrylamide and methacrylamide.
Examples of the (meth) acrylic acid ester having a non-crosslinkable tertiary amino group include (meth) acrylic acid (N, N-dimethylamino) ethyl and (meth) acrylic acid (N, N-dimethylamino). Examples include propyl and 4- (meth) acryloyl morpholine.
These monomers may be used alone or in combination of two or more.

In the present embodiment, as the second copolymer component, a carboxyl group-containing monomer or a hydroxyl group-containing monomer is preferable, and acrylic acid is more preferable. When the acrylic copolymer contains a copolymer component derived from 2-ethylhexyl acrylate and a copolymer component derived from acrylic acid, the copolymer component derived from acrylic acid in the total mass of the acrylic copolymer The proportion of the mass of the above is preferably 1% by mass or less, and more preferably 0.1% by mass or more and 0.5% by mass or less. When the proportion of acrylic acid is 1% by mass or less, it is possible to prevent the cross-linking of the acrylic copolymer from proceeding too quickly when the pressure-sensitive adhesive composition contains a cross-linking agent.

The acrylic copolymer may contain a copolymer component derived from two or more kinds of functional group-containing monomers. For example, the acrylic copolymer may be a ternary copolymer, and an acrylic copolymer obtained by copolymerizing 2-ethylhexyl acrylate, a carboxyl group-containing monomer, and a hydroxyl group-containing monomer is preferable. The carboxyl group-containing monomer is preferably acrylic acid, and the hydroxyl group-containing monomer is preferably 2-hydroxyethyl acrylate. The proportion of the copolymer component derived from 2-ethylhexyl acrylate in the acrylic copolymer is 80% by mass or more and 95% by mass or less, and the proportion of the mass of the copolymer component derived from acrylic acid is 1% by mass or less. It is preferable that the balance is a copolymer component derived from 2-hydroxyethyl acrylate.

The weight average molecular weight (Mw) of the acrylic copolymer is preferably 300,000 or more and 2 million or less, more preferably 600,000 or more and 1.5 million or less, and further preferably 800,000 or more and 1.2 million or less. preferable. When the weight average molecular weight Mw of the acrylic copolymer is 300,000 or more, it can be peeled off without the adhesive residue on the adherend. When the weight average molecular weight Mw of the acrylic copolymer is 2 million or less, it can be reliably attached to the adherend.
The weight average molecular weight Mw of the acrylic copolymer is a standard polystyrene-equivalent value measured by the Gel Permeation Chromatography (GPC) method.

The acrylic copolymer can be produced according to a conventionally known method using the above-mentioned various raw material monomers.

The form of copolymerization of the acrylic copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.
In the present embodiment, the content of the acrylic copolymer in the pressure-sensitive adhesive composition is preferably 40% by mass or more and 90% by mass or less, and more preferably 50% by mass or more and 90% by mass or less.

The tacky aid preferably contains a rubber-based material having a reactive group as a main component. When the pressure-sensitive adhesive composition contains a reactive pressure-sensitive adhesive, the adhesive residue can be reduced. The content of the pressure-sensitive adhesive in the pressure-sensitive adhesive composition is preferably 3% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 30% by mass or less. When the content of the pressure-sensitive adhesive in the pressure-sensitive adhesive composition is 3% by mass or more, the generation of adhesive residue can be suppressed, and when it is 50% by mass or less, the decrease in adhesive strength can be suppressed.
In the present specification, the inclusion of a rubber-based material having a reactive group as a main component means that the ratio of the mass of the rubber-based material having a reactive group to the total mass of the pressure-sensitive adhesive aid exceeds 50% by mass. To do. In the present embodiment, the proportion of the rubber-based material having a reactive group in the tackifier is preferably more than 50% by mass, more preferably 80% by mass or more. It is also preferred that the tackifier is made of a rubber-based material that has a substantially reactive group.

The reactive group is preferably one or more functional groups selected from the group consisting of a hydroxyl group, an isocyanate group, an amino group, an oxylan group, an acid anhydride group, an alkoxy group, an acryloyl group and a methacryloyl group. It is preferable to have. The reactive group contained in the rubber-based material may be one type or two or more types. The rubber-based material having a hydroxyl group may further have the above-mentioned reactive group. Further, the number of reactive groups may be one or two or more in one molecule constituting the rubber-based material.

The rubber-based material is not particularly limited, but a polybutadiene-based resin and a hydrogenated product of a polybutadiene-based resin are preferable, and a hydrogenated product of a polybutadiene-based resin is more preferable.
Examples of the polybutadiene resin include a resin having a 1,4-repeating unit, a resin having a 1,2-repeating unit, and a resin having both a 1,4-repeating unit and a 1,2-repeating unit. The hydrogenated polybutadiene resin of the present embodiment also includes a hydride of a resin having these repeating units.

The polybutadiene-based resin and the hydrogenated additive of the polybutadiene-based resin preferably have reactive groups at both ends. The reactive groups at both ends may be the same or different. The reactive group at both ends is preferably one or more functional groups selected from the group consisting of a hydroxyl group, an isocyanate group, an amino group, an oxylan group, an acid anhydride group, an alkoxy group, an acryloyl group and a methacryloyl group. It is preferably a hydroxyl group. In the polybutadiene resin and the hydrogenated product of the polybutadiene resin, it is more preferable that both ends are hydroxyl groups.

The pressure-sensitive adhesive composition according to the present embodiment preferably contains a crosslinked product obtained by cross-linking a composition containing a cross-linking agent in addition to the above-mentioned acrylic copolymer and pressure-sensitive adhesive. Further, it is also preferable that the solid content of the pressure-sensitive adhesive composition is substantially composed of a crosslinked product obtained by cross-linking the above-mentioned acrylic copolymer, the pressure-sensitive adhesive and a cross-linking agent as described above. Here, "substantially" means that the solid content of the pressure-sensitive adhesive composition consists only of the crosslinked product, except for trace impurities that are inevitably mixed with the pressure-sensitive adhesive.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, metal chelate-based cross-linking agents, amine-based cross-linking agents, and amino resin-based cross-linking agents. These cross-linking agents may be used alone or in combination of two or more.
From the viewpoint of improving the heat resistance and adhesive strength of the pressure-sensitive adhesive composition, among these cross-linking agents, a cross-linking agent containing a compound having an isocyanate group as a main component (isocyanate-based cross-linking agent) is preferable. Examples of the isocyanate-based cross-linking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and the like. Multivalent isocyanates such as diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate. Examples include compounds.
Further, the polyisocyanate compound may be a trimethylolpropan adduct-type modified product of the above-mentioned compound, a biuret-type modified product reacted with water, or an isocyanurate-type modified product having an isocyanurate ring.
In the present specification, the cross-linking agent containing a compound having an isocyanate group as a main component means that the ratio of the mass of the compound having an isocyanate group to the total mass of the components constituting the cross-linking agent is 50% by mass or more. To do.

The content of the cross-linking agent in the pressure-sensitive adhesive composition is preferably 0.1 part by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the acrylic copolymer. More preferably, it is 5 parts by mass or more and 10 parts by mass or less. When the content of the cross-linking agent in the pressure-sensitive adhesive composition is within such a range, the adhesiveness between the layer containing the pressure-sensitive adhesive composition (the pressure-sensitive adhesive layer) and the adherend (for example, the base material) is improved. It is possible to shorten the curing period for stabilizing the adhesive properties after the production of the adhesive sheet.

In the present embodiment, from the viewpoint of heat resistance of the pressure-sensitive adhesive composition, the isocyanate-based cross-linking agent is more preferably a compound having an isocyanurate ring (isocyanurate-type modified product). The compound having an isocyanurate ring is preferably blended in an amount of 0.7 equivalents or more and 1.5 equivalents or less with respect to the hydroxyl equivalents of the acrylic copolymer. When the compounding amount of the compound having an isocyanurate ring is 0.7 equivalents or more, the adhesive strength does not become too high after heating, the adhesive sheet can be easily peeled off, and the adhesive residue can be reduced. When the compounding amount of the compound having an isocyanurate ring is 1.5 equivalents or less, it is possible to prevent the initial adhesive strength from becoming too low and prevent the adhesiveness from being lowered.

When the pressure-sensitive adhesive composition in the present embodiment contains a cross-linking agent, it is preferable that the pressure-sensitive adhesive composition further contains a cross-linking accelerator. The cross-linking accelerator is preferably selected and used as appropriate according to the type of the cross-linking agent and the like. For example, when the pressure-sensitive adhesive composition contains a polyisocyanate compound as a cross-linking agent, it is preferable to further contain an organometallic compound-based cross-linking accelerator such as an organotin compound.

-Silicone-based pressure-sensitive adhesive composition When the pressure-sensitive adhesive layer 12 contains a silicone-based pressure-sensitive adhesive composition, the silicone-based pressure-sensitive adhesive composition preferably contains an addition polymerization type silicone resin. In the present specification, a silicone-based pressure-sensitive adhesive composition containing an addition polymerization-type silicone resin is referred to as an addition-reaction type silicone-based pressure-sensitive adhesive composition.

The addition reaction type silicone-based pressure-sensitive adhesive composition contains a main agent and a cross-linking agent. The addition reaction type silicone-based pressure-sensitive adhesive composition has an advantage that it can be used only by the primary curing at a low temperature and does not require the secondary curing at a high temperature. By the way, the conventional peroxide-curable silicone-based adhesive requires secondary curing at a high temperature such as 150 ° C. or higher.
Therefore, by using the addition reaction type silicone-based pressure-sensitive adhesive composition, it is possible to manufacture a pressure-sensitive adhesive sheet at a relatively low temperature, and a base material 11 having excellent energy economy and relatively low heat resistance is used. It is also possible to manufacture the adhesive sheet 10. In addition, unlike peroxide-curable silicone-based adhesives, no by-products are generated during curing, so there are no problems such as odor and corrosion.

The addition-reaction silicone-based pressure-sensitive adhesive composition usually consists of a main agent consisting of a mixture of a silicone resin component and a silicone rubber component, a cross-linking agent containing a hydrosilyl group (SiH group), and a curing catalyst used as necessary. Become.
The silicone resin component is an organopolysiloxane having a network structure obtained by hydrolyzing organochlorosilane and organoalkoxysilane and then performing a dehydration condensation reaction.
The silicone rubber component is a diorganopolysiloxane having a linear structure.
As the organogroup, both the silicone resin component and the silicone rubber component are a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group and the like. Some of the above-mentioned organogroups are vinyl group, hexenyl group, allyl group, butenyl group, pentenyl group, octenyl group, (meth) acryloyl group, (meth) acryloylmethyl group, (meth) acryloylpropyl group, and cyclohexenyl. Substituted with an unsaturated group such as a group. An organo group having a vinyl group, which is easily available industrially, is preferable. In the addition reaction type silicone-based pressure-sensitive adhesive composition, cross-linking proceeds by the addition reaction of an unsaturated group and a hydrosilyl group to form a network structure, and tackiness is exhibited.
The number of unsaturated groups such as vinyl groups is usually 0.05 or more and 3.0 or less, preferably 0.1 or more and 2.5 or less, relative to 100 organogroups. By setting the number of unsaturated groups to 0.05 or more of 100 organogroups, it is possible to prevent the reactivity with the hydrosilyl group from being lowered and becoming difficult to cure, and to impart an appropriate adhesive force. .. By setting the number of unsaturated groups to 3.0 or less with respect to 100 organogroups, it is possible to prevent the crosslink density of the adhesive from increasing and the adhesive force and cohesive force from increasing, which adversely affect the adherend surface.

Specific examples of the organopolysiloxane as described above include KS-3703 manufactured by Shin-Etsu Chemical Industry Co., Ltd. (the number of vinyl groups is 0.6 for every 100 methyl groups) and Toray Dowcorning. BY23-753 (the number of vinyl groups is 0.1 for 100 methyl groups) and BY24-162 (the number of vinyl groups is 1.4 for 100 methyl groups) manufactured by the company. Things) and so on. Further, SD4560PSA, SD4570PSA, SD4580PSA, SD4584PSA, SD4585PSA, SD4587L, SD4592PSA and the like manufactured by Toray Dow Corning Co., Ltd. can also be used.
As described above, organopolysiloxane, which is a silicone resin component, is usually used by mixing with a silicone rubber component, but as the silicone rubber component, KS-3800 manufactured by Shin-Etsu Chemical Industry Co., Ltd. (the number of vinyl groups is high). 7.6 for every 100 methyl groups), BY24-162 manufactured by Toray Dow Corning (the number of vinyl groups is 1.4 for every 100 methyl groups), BY24- Examples thereof include 843 (having no unsaturated group) and SD-7292 (the number of vinyl groups is 5.0 for every 100 methyl groups).
Specific examples of the addition reaction type silicone as described above are described in, for example, Japanese Patent Application Laid-Open No. 10-219229.

The cross-linking agent usually has 0.5 or more and 10 or less hydrogen atoms bonded to silicon atoms, preferably 1 or more, with respect to one unsaturated group such as a vinyl group of a silicone resin component and a silicone rubber component. Mix so that the number is 2.5 or less. By setting the number to 0.5 or more, it is possible to prevent the reaction between the unsaturated group such as the vinyl group and the hydrosilyl group from not completely proceeding and resulting in poor curing. By setting the number to 10 or less, it is possible to prevent the cross-linking agent from remaining unreacted and adversely affecting the adherend surface.

The addition-reaction type silicone-based pressure-sensitive adhesive composition preferably contains a curing catalyst together with the above-mentioned addition-reaction type silicone component (main agent composed of a silicone resin component and a silicone rubber component) and a cross-linking agent.
This curing catalyst is used to promote the hydrosilylation reaction between the unsaturated group in the silicone resin component and the silicone rubber component and the Si—H group in the cross-linking agent.
As the curing catalyst, platinum-based catalysts, that is, platinum chloride acid, an alcohol solution of platinum chloride acid, a reaction product of platinum chloride acid and an alcohol solution, a reaction product of platinum chloride acid and an olefin compound, platinum chloride acid and vinyl. Examples thereof include a reaction product with a group-containing siloxane compound, a platinum-olefin complex, a platinum-vinyl group-containing siloxane complex, and a platinum-phosphorus complex. Specific examples of the curing catalyst as described above are described in, for example, JP-A-2006-28311 and JP-A-10-147758.
More specifically, examples of commercially available products include SRX-212 manufactured by Toray Dow Corning Co., Ltd. and PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.

The blending amount of the curing catalyst is usually 5 ppm or more and 2000 ppm or less, preferably 10 ppm or more and 500 ppm or less, based on the total amount of the silicone resin component and the silicone rubber component as the platinum content. By setting it to 5 ppm or more, it is possible to prevent a decrease in curability and a decrease in cross-linking density, that is, a decrease in adhesive force and cohesive force (holding force), and by setting it to 2000 ppm or less, cost increase is prevented and an adhesive is used. The stability of the layer can be maintained, and the excessively used curing catalyst is prevented from adversely affecting the adherend surface.

In the addition-reaction type silicone-based pressure-sensitive adhesive composition, the adhesive strength is exhibited even at room temperature by blending each of the above-mentioned components, but the addition-reaction type silicone-based pressure-sensitive adhesive composition is applied to the base material 11 or the release sheet described later. Then, after the base material 11 and the release sheet are bonded together, heating or irradiation with active energy rays is performed to promote the cross-linking reaction between the silicone resin component and the silicone rubber component by the cross-linking agent from the viewpoint of adhesive strength stability. preferable.

When the cross-linking reaction is promoted by heating, the heating temperature is usually 60 ° C. or higher and 140 ° C. or lower, preferably 80 ° C. or higher and 130 ° C. or lower. By heating at 60 ° C or higher, the cross-linking between the silicone resin component and the silicone rubber component is insufficient to prevent insufficient adhesive strength, and by heating at 140 ° C or lower, the base sheet is heat-shrinked and wrinkled. It can be prevented from occurring, deteriorating, or discoloring.

When irradiating an active energy ray to promote the cross-linking reaction, an active energy ray having an energy quantum in an electromagnetic wave or a charged particle beam, that is, an active light such as an ultraviolet ray or an electron beam can be used. When cross-linking by irradiating with an electron beam, a photopolymerization initiator is not required, but when cross-linking by irradiating with active light such as ultraviolet rays, it is preferable to have a photopolymerization initiator present.
The photopolymerization initiator when irradiated with ultraviolet rays is not particularly limited, and any photopolymerization initiator may be appropriately selected and used from the photopolymerization initiators conventionally used in ultraviolet curable resins. it can. Examples of the photopolymerization initiator include benzoins, benzophenones, acetophenones, α-hydroxyketones, α-aminoketones, α-diketones, α-diketone dialkyl acetals, anthraquinones, thioxanthones, and other compounds. Can be mentioned.
These photopolymerization initiators may be used alone or in combination of two or more. The amount used is usually 0.01 parts by mass or more and 30 parts by mass or less, preferably 0.05 parts by mass or more, based on 100 parts by mass of the total amount of the addition reaction type silicone component and the cross-linking agent used as the main agent. It is selected in the range of 20 parts by mass or less.
A pressure-sensitive adhesive sheet having stable adhesive strength can be obtained by cross-linking by heating or irradiating with active energy rays.

The accelerating voltage of an electron beam when cross-linking by irradiating an electron beam which is one of the active energy rays is generally 130 kV or more and 300 kV or less, preferably 150 kV or more and 250 kV or less. By irradiating with an accelerating voltage of 130 kV or more, it is possible to prevent insufficient cross-linking between the silicone resin component and the silicone rubber component and insufficient adhesive strength, and by irradiating with an accelerating voltage of 300 kV or less, the adhesive It is possible to prevent the layer and the base sheet from deteriorating or discoloring. The preferred range of beam current is 1 mA or more and 100 mA or less.
The dose of the irradiated electron beam is preferably 1 Mrad or more and 70 Mrad or less, and more preferably 2 Mrad or more and 20 Mrad or less. By irradiating with a dose of 1 Mrad or more, it is possible to prevent the pressure-sensitive adhesive layer and the base material sheet from deteriorating or discoloring, and it is possible to prevent the adhesiveness from becoming insufficient due to insufficient cross-linking. By irradiating with a dose of 70 Mrad or less, it is possible to prevent a decrease in cohesive force due to deterioration or discoloration of the pressure-sensitive adhesive layer, and prevent deterioration or shrinkage of the base sheet.
The irradiation amount in the case of ultraviolet irradiation is appropriately selected, but the light amount is 100 mJ / cm ² or more and 500 mJ / cm ² or less, and the illuminance is 10 mW / cm ² or more and 500 mW / cm ² or less.
Heating and irradiation with active energy rays are preferably performed in a nitrogen atmosphere in order to prevent reaction inhibition by oxygen.

The thickness of the pressure-sensitive adhesive layer 12 is appropriately determined according to the use of the pressure-sensitive adhesive sheet 10. In the present embodiment, the thickness of the pressure-sensitive adhesive layer 12 is preferably 5 μm or more and 60 μm or less, and more preferably 10 μm or more and 50 μm or less. If the thickness of the pressure-sensitive adhesive layer 12 is too thin, the pressure-sensitive adhesive layer 12 may not be able to follow the unevenness of the circuit surface of the semiconductor chip, and a gap may be formed. An interlayer insulating material, a sealing resin, or the like may enter the gap, and the electrode pad for wiring connection on the chip circuit surface may be blocked. When the thickness of the pressure-sensitive adhesive layer 12 is 5 μm or more, the pressure-sensitive adhesive layer 12 can easily follow the unevenness of the chip circuit surface, and the generation of gaps can be prevented. Further, if the thickness of the pressure-sensitive adhesive layer 12 is too thick, the semiconductor chip may sink into the pressure-sensitive adhesive layer, and a step may occur between the semiconductor chip portion and the resin portion that seals the semiconductor chip. If such a step occurs, the wiring may be broken during rewiring. If the thickness of the pressure-sensitive adhesive layer 12 is 60 μm or less, a step is unlikely to occur.

The pressure-sensitive adhesive composition may contain other components as long as the effects of the present invention are not impaired. Other components that may be included in the pressure-sensitive adhesive composition include, for example, organic solvents, flame retardants, pressure-imparting agents, UV absorbers, light stabilizers, antioxidants, antistatic agents, preservatives, fungicides, plasticizers. Agents, antifoaming agents, colorants, fillers, wettability regulators and the like.
The addition-reactive silicone-based pressure-sensitive adhesive composition may contain non-reactive polyorganosiloxanes such as polydimethylsiloxane and polymethylphenylsiloxane as additives.

More specific examples of the pressure-sensitive adhesive composition according to the present embodiment include, for example, the following examples of the pressure-sensitive adhesive composition, but the present invention is not limited to such examples.
As an example of the pressure-sensitive adhesive composition according to the present embodiment, the acrylic copolymer contains an acrylic copolymer, a pressure-sensitive auxiliary agent, and a cross-linking agent, and the acrylic copolymer contains at least 2-ethylhexyl acrylate and a carboxyl group-containing monomer. And an acrylic copolymer obtained by copolymerizing a hydroxyl group-containing monomer, the tackifier contains a rubber-based material having a reactive group as a main component, and the cross-linking agent is an isocyanate-based cross-linking agent. A pressure-sensitive adhesive composition can be mentioned.
As an example of the pressure-sensitive adhesive composition according to the present embodiment, the acrylic copolymer contains an acrylic copolymer, a pressure-sensitive auxiliary agent, and a cross-linking agent, and the acrylic copolymer contains at least 2-ethylhexyl acrylate and a carboxyl group-containing monomer. And an acrylic copolymer obtained by copolymerizing a hydroxyl group-containing monomer, the pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition in which the pressure-sensitive adhesive is polybutadiene with both-terminal hydroxyl groups and the cross-linking agent is an isocyanate-based cross-linking agent. Can be mentioned.
As an example of the pressure-sensitive adhesive composition according to the present embodiment, an acrylic copolymer, a pressure-sensitive adhesive, and a cross-linking agent are contained, and the acrylic copolymer contains at least 2-ethylhexyl acrylate, acrylic acid, and acrylic. It is an acrylic copolymer obtained by copolymerizing 2-hydroxyethyl acid acid, the tackifier contains a rubber-based material having a reactive group as a main component, and the cross-linking agent is an isocyanate-based cross-linking agent. Some tackant compositions are mentioned.
As an example of the pressure-sensitive adhesive composition according to the present embodiment, an acrylic copolymer, a pressure-sensitive adhesive, and a cross-linking agent are contained, and the acrylic copolymer contains at least 2-ethylhexyl acrylate, acrylic acid, and acrylic. A pressure-sensitive adhesive composition obtained by copolymerizing 2-hydroxyethyl acid acid, wherein the pressure-sensitive adhesive is polybutadiene with both-terminal hydroxyl groups, and the cross-linking agent is an isocyanate-based cross-linking agent. Can be mentioned.
In these examples of the pressure-sensitive adhesive composition according to the present embodiment, the proportion of the copolymer component derived from 2-ethylhexyl acrylate in the acrylic copolymer is 80% by mass or more and 95% by mass or less, and carboxyl. It is preferable that the mass ratio of the copolymer component derived from the group-containing monomer is 1% by mass or less and the balance is another copolymer component, and the other copolymer component is a copolymer derived from a hydroxyl group-containing monomer. It preferably contains a copolymer component.
In these examples of the pressure-sensitive adhesive composition according to the present embodiment, when the pressure-sensitive adhesive layer is formed using this pressure-sensitive adhesive composition, the surface free energy of the pressure-sensitive adhesive layer is 10 mJ / m ² or more and 22 mJ / m ^2. It is as follows.

(Release sheet)
The release sheet RL is not particularly limited. For example, from the viewpoint of ease of handling, the release sheet RL preferably includes a release base material and a release agent layer formed by applying a release agent on the release base material. Further, the release sheet RL may have a release agent layer on only one side of the release base material, or may have a release agent layer on both sides of the release base material. Examples of the release base material include a paper base material, a laminated paper obtained by laminating a thermoplastic resin such as polyethylene on the paper base material, a plastic film, and the like. Examples of the paper base material include glassine paper, coated paper, cast coated paper and the like. Examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. Examples of the release agent include olefin-based resins, rubber-based elastomers (for example, butadiene-based resins, isoprene-based resins, etc.), long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and silicone-based resins.

The thickness of the release sheet RL is not particularly limited. The thickness of the release sheet RL is usually 20 μm or more and 200 μm or less, and preferably 25 μm or more and 150 μm or less.
The thickness of the release agent layer is not particularly limited. When a solution containing a release agent is applied to form a release agent layer, the thickness of the release agent layer is preferably 0.01 μm or more and 2.0 μm or less, and 0.03 μm or more and 1.0 μm or less. More preferred.
When a plastic film is used as the release base material, the thickness of the plastic film is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less.

The pressure-sensitive adhesive sheet 10 according to this embodiment preferably exhibits the following adhesive strength after heating. First, the adhesive sheet 10 is attached to an adherend (copper foil or polyimide film), heated at 100 ° C. for 30 minutes, then heated at 180 ° C. and 30 minutes, and further at 190 ° C. and 1 After heating under the condition of time, the adhesive force of the adhesive layer 12 to the copper foil at room temperature and the adhesive force of the adhesive layer 12 to the polyimide film at room temperature are 0.7 N / 25 mm or more and 2.0 N / 25 mm, respectively. The following is preferable. When the adhesive strength after such heating is 0.7 N / 25 mm or more, it is possible to prevent the adhesive sheet 10 from peeling off from the adherend when the base material or the adherend is deformed by the heating. Further, if the adhesive force after heating is 2.0 N / 25 mm or less, the peeling force does not become too high, and the adhesive sheet 10 can be easily peeled from the adherend. In the present specification, the room temperature is a temperature of 22 ° C. or higher and 24 ° C. or lower. In the present specification, the adhesive strength is a value measured by a 180 ° peeling method at a pulling speed of 300 mm / min and a width of the adhesive sheet of 25 mm.

(Manufacturing method of adhesive sheet)
The method for producing the adhesive sheet 10 is not particularly limited.
For example, the pressure-sensitive adhesive sheet 10 is manufactured through the following steps. First, the pressure-sensitive adhesive composition is applied onto the first base material surface 11a of the base material 11 to form a coating film. Next, the coating film is dried to form the pressure-sensitive adhesive layer 12. Then, the release sheet RL is attached so as to cover the pressure-sensitive adhesive layer 12.
Further, as another manufacturing method of the pressure-sensitive adhesive sheet 10, it is manufactured through the following steps. First, the pressure-sensitive adhesive composition is applied onto the release sheet RL to form a coating film. Next, the coating film is dried to form the pressure-sensitive adhesive layer 12, and the first base material surface 11a of the base material 11 is attached to the pressure-sensitive adhesive layer 12.

When the pressure-sensitive adhesive composition is applied to form the pressure-sensitive adhesive layer 12, it is preferable to dilute the pressure-sensitive adhesive composition with an organic solvent to prepare a coating liquid and use it. Examples of the organic solvent include toluene, ethyl acetate, methyl ethyl ketone and the like. The method of applying the coating liquid is not particularly limited. Examples of the coating method include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.
In order to prevent the organic solvent and the low boiling point component from remaining in the pressure-sensitive adhesive layer 12, it is preferable to apply the coating liquid to the base material 11 or the release sheet RL, and then heat and dry the coating film. When a cross-linking agent is blended in the pressure-sensitive adhesive composition, it is preferable to heat the coating film in order to promote the cross-linking reaction and improve the cohesive force.

(Use of adhesive sheet)
The pressure-sensitive adhesive sheet 10 is used when sealing a semiconductor element. The pressure-sensitive adhesive sheet 10 is not mounted on a metal lead frame, and is preferably used when sealing a semiconductor element attached to the pressure-sensitive adhesive sheet 10. Specifically, the pressure-sensitive adhesive sheet 10 is not used when sealing the semiconductor element mounted on the metal lead frame, but seals the semiconductor element in a state of being attached to the pressure-sensitive adhesive layer 12. It is preferable to be used when. Examples of the form in which the semiconductor element is packaged without using the metal lead frame include a panel scale package (PSP) and a wafer level package (Wafer Level Package; WLP).
The pressure-sensitive adhesive sheet 10 includes a step of attaching a frame member having a plurality of openings formed to the pressure-sensitive adhesive sheet 10 and a step of attaching a semiconductor chip to the pressure-sensitive adhesive layer 12 exposed at the openings of the frame member. It is preferably used in a process having a step of covering the semiconductor chip with a sealing resin and a step of thermosetting the sealing resin.

(Manufacturing method of semiconductor device)
A method of manufacturing a semiconductor device using the pressure-sensitive adhesive sheet 10 according to the present embodiment will be described.
2A to 2E show schematic views illustrating a method of manufacturing a semiconductor device according to the present embodiment. In addition, in the drawing, there is a part shown by being enlarged or reduced for ease of explanation.
The method for manufacturing a semiconductor device according to the present embodiment includes a step of attaching a frame member 20 having a plurality of openings 21 formed to the adhesive sheet 10 (adhesive sheet attaching step) and a step of attaching the frame member 20 to the openings 21 of the frame member 20. A step of attaching the semiconductor chip CP to the exposed pressure-sensitive adhesive layer 12 (bonding step), a step of covering the semiconductor chip CP with the sealing resin 30 (sealing step), and a step of thermally curing the sealing resin 30 (sealing resin 30). Heat curing step) and. If necessary, after the thermosetting step, a step (reinforcing member sticking step) of sticking the reinforcing member 40 to the sealing body 50 sealed with the sealing resin 30 may be carried out.
Each step will be described below.

-Adhesive Sheet Attaching Step FIG. 2A shows a schematic view illustrating a step of attaching the frame member 20 to the adhesive layer 12 of the adhesive sheet 10.
The frame member 20 according to the present embodiment is formed in a grid pattern and has a plurality of openings 21. The frame member 20 is preferably made of a heat-resistant material. Examples of the material of the frame member 20 include metals such as copper and stainless steel, and heat-resistant resins such as polyimide resin and glass epoxy resin.
The opening 21 is a hole that penetrates the front and back surfaces of the frame member 20. The shape of the opening 21 is not particularly limited as long as the semiconductor chip CP can be accommodated in the frame. The depth of the hole of the opening 21 is also not particularly limited as long as it can accommodate the semiconductor chip CP.

Bonding process FIG. 2B shows a schematic diagram illustrating a process of attaching the semiconductor chip CP to the pressure-sensitive adhesive layer 12.
When the adhesive sheet 10 is attached to the frame member 20, the adhesive layer 12 is exposed at each opening 21 according to the shape of the opening 21. The semiconductor chip CP is attached to the pressure-sensitive adhesive layer 12 of each opening 21. The semiconductor chip CP is attached so as to cover the circuit surface with the adhesive layer 12.

The semiconductor chip CP is manufactured, for example, by performing a back grind step for grinding the back surface of the semiconductor wafer on which the circuit is formed and a dicing step for individualizing the semiconductor wafer. In the dicing step, a semiconductor chip CP (semiconductor element) is obtained by attaching a semiconductor wafer to an adhesive layer of a dicing sheet and separating the semiconductor wafer into pieces using a cutting means such as a dicing saw.
The dicing device is not particularly limited, and a known dicing device can be used. Further, the dicing conditions are not particularly limited. In addition, instead of the method of dicing using a dicing blade, a laser dicing method, a stealth dicing method, or the like may be used.

After the dicing step, the dicing sheet may be stretched to carry out an expanding step of widening the distance between the plurality of semiconductor chip CPs. By carrying out the expanding step, the semiconductor chip CP can be picked up by using a conveying means such as a collet. Further, by carrying out the expanding step, the adhesive force of the adhesive layer of the dicing sheet is reduced, and the semiconductor chip CP can be easily picked up.
When the adhesive composition of the dicing sheet or the adhesive layer contains an energy ray-polymerizable compound, the adhesive layer is irradiated with energy rays from the base material side of the dicing sheet to obtain the energy ray-polymerizable compound. Let it cure. When the energy ray-polymerizable compound is cured, the cohesive force of the adhesive layer is increased, and the adhesive force of the adhesive layer can be lowered. Examples of the energy ray include ultraviolet rays (UV) and electron beams (EB), and ultraviolet rays are preferable. The energy ray irradiation may be performed at any stage after the semiconductor wafer is attached and before the semiconductor chip is peeled off (picked up). For example, energy rays may be irradiated before or after dicing, or energy rays may be irradiated after the expanding step.

-Sealing step and thermosetting step FIG. 2C shows a schematic diagram illustrating a step of sealing the semiconductor chip CP and the frame member 20 attached to the adhesive sheet 10.
The material of the sealing resin 30 is a thermosetting resin, and examples thereof include an epoxy resin. The epoxy resin used as the sealing resin 30 may contain, for example, a phenol resin, an elastomer, an inorganic filler, a curing accelerator, and the like.
The method of covering the semiconductor chip CP and the frame member 20 with the sealing resin 30 is not particularly limited.
In the present embodiment, an embodiment using the sheet-shaped sealing resin 30 will be described as an example. The sheet-shaped sealing resin 30 is placed so as to cover the semiconductor chip CP and the frame member 20, and the sealing resin 30 is heat-cured to form the sealing resin layer 30A. In this way, the semiconductor chip CP and the frame member 20 are embedded in the sealing resin layer 30A. When the sheet-shaped sealing resin 30 is used, it is preferable to seal the semiconductor chip CP and the frame member 20 by a vacuum laminating method. By this vacuum laminating method, it is possible to prevent the formation of a gap between the semiconductor chip CP and the frame member 20. The temperature condition range of heat curing by the vacuum laminating method is, for example, 80 ° C. or higher and 120 ° C. or lower.

In the sealing step, a laminated sheet in which the sheet-shaped sealing resin 30 is supported by a resin sheet such as polyethylene terephthalate may be used. In this case, after the laminated sheet is placed so as to cover the semiconductor chip CP and the frame member 20, the resin sheet may be peeled from the sealing resin 30 and the sealing resin 30 may be heat-cured. Examples of such laminated sheets include ABF films (manufactured by Ajinomoto Fine-Techno Co., Ltd.).

As a method of sealing the semiconductor chip CP and the frame member 20, a transfer molding method may be adopted. In this case, for example, the semiconductor chip CP and the frame member 20 attached to the adhesive sheet 10 are housed inside the mold of the sealing device. A fluid resin material is injected into the mold to cure the resin material. In the case of the transfer molding method, the heating and pressure conditions are not particularly limited. As an example of normal conditions in the transfer molding method, a temperature of 150 ° C. or higher and a pressure of 4 MPa or higher and 15 MPa or lower are maintained for 30 seconds or longer and 300 seconds or shorter. Then, the pressurization is released, the mixture is taken out from the sealing device and allowed to stand in an oven, and maintained at 150 ° C. or higher for 2 hours or longer and 15 hours or shorter. In this way, the semiconductor chip CP and the frame member 20 are sealed.

When the sheet-shaped sealing resin 30 is used in the above-mentioned sealing step, the first heat pressing step may be performed before the step of thermosetting the sealing resin 30 (thermosetting step). In the first heat pressing step, the semiconductor chip CP coated with the sealing resin 30 and the adhesive sheet 10 with the frame member 20 are sandwiched between the plate-shaped members from both sides and pressed under predetermined temperature, time, and pressure conditions. .. By carrying out the first heat pressing step, the sealing resin 30 can be easily filled in the gap between the semiconductor chip CP and the frame member 20. Further, by carrying out the heat pressing step, the unevenness of the sealing resin layer 30A made of the sealing resin 30 can be flattened. As the plate-shaped member, for example, a metal plate such as stainless steel can be used.

When the adhesive sheet 10 is peeled off after the thermosetting step, the semiconductor chip CP and the frame member 20 sealed with the sealing resin 30 are obtained. Hereinafter, this may be referred to as a sealing body 50.

-Reinforcing member sticking process FIG. 2D shows a schematic view illustrating a step of sticking the reinforcing member 40 to the sealing body 50.
After peeling off the adhesive sheet 10, a rewiring step and a bumping step of forming a rewiring layer on the circuit surface of the exposed semiconductor chip CP are performed. In order to improve the handleability of the sealing body 50 in such a rewiring step and a bumping step, a step of sticking the reinforcing member 40 to the sealing body 50 (reinforcing member sticking step) is carried out as necessary. You may. When the reinforcing member attaching step is carried out, it is preferable to carry out the step before peeling off the adhesive sheet 10. As shown in FIG. 2D, the sealing body 50 is supported in a state of being sandwiched between the adhesive sheet 10 and the reinforcing member 40.

In the present embodiment, the reinforcing member 40 includes a heat-resistant reinforcing plate 41 and a heat-resistant adhesive layer 42.
Examples of the reinforcing plate 41 include a plate-shaped member containing a heat-resistant resin such as a polyimide resin and a glass epoxy resin.
The adhesive layer 42 adheres the reinforcing plate 41 and the sealing body 50. The adhesive layer 42 is appropriately selected depending on the materials of the reinforcing plate 41 and the sealing resin layer 30A. For example, when the sealing resin layer 30A contains an epoxy resin and the reinforcing plate 41 contains a glass epoxy resin, the adhesive layer 42 is preferably a glass cloth containing a thermoplastic resin, and the adhesive layer 42 has a glass cloth. As the contained thermoplastic resin, a bismaleimide triazine resin (BT resin) is preferable.

In the reinforcing member attaching step, the adhesive layer 42 is sandwiched between the sealing resin layer 30A of the sealing body 50 and the reinforcing plate 41, and further sandwiched between the reinforcing plate 41 side and the adhesive sheet 10 side, respectively, and predetermined. It is preferable to carry out a second heating pressing step of pressing under the conditions of temperature, time and pressure. The sealing body 50 and the reinforcing member 40 are temporarily fixed by the second heating press step. After the second heat pressing step, it is preferable to heat the temporarily fixed sealing body 50 and the reinforcing member 40 under the conditions of a predetermined temperature and time in order to cure the adhesive layer 42. The conditions for heat curing are appropriately set according to the material of the adhesive layer 42, and are, for example, 185 ° C., 80 minutes, and 2.4 MPa. Also in the second heating press step, a metal plate such as stainless steel can be used as the plate-shaped member.

-Peeling step FIG. 2E shows a schematic view illustrating a step of peeling the adhesive sheet 10.
In the present embodiment, since the base material 11 of the pressure-sensitive adhesive sheet 10 is bendable, the pressure-sensitive adhesive sheet 10 can be easily peeled off from the frame member 20, the semiconductor chip CP, and the sealing resin layer 30A while bending the pressure-sensitive adhesive sheet 10. The peeling angle θ is not particularly limited, but it is preferable to peel the adhesive sheet 10 at a peeling angle θ of 90 degrees or more. When the peeling angle θ is 90 degrees or more, the adhesive sheet 10 can be easily peeled from the frame member 20, the semiconductor chip CP, and the sealing resin layer 30A. The peeling angle θ is preferably 90 degrees or more and 180 degrees or less, and more preferably 135 degrees or more and 180 degrees or less. By peeling the adhesive sheet 10 while bending it in this way, the adhesive sheet 10 can be peeled off while reducing the load applied to the frame member 20, the semiconductor chip CP, and the sealing resin layer 30A. Damage to the chip CP and the sealing resin layer 30A can be suppressed. After peeling off the adhesive sheet 10, the above-mentioned rewiring step, bumping step, and the like are carried out. After the adhesive sheet 10 is peeled off, and before the rewiring step, the bumping step, and the like are carried out, the above-mentioned reinforcing member sticking step may be carried out, if necessary.

When the reinforcing member 40 is attached, the reinforcing member 40 is peeled off from the sealing body 50 when the support by the reinforcing member 40 is no longer necessary after the rewiring step, the bumping step, and the like are performed.
After that, the encapsulant 50 is individualized in units of semiconductor chip CP (individualization step). The method for individualizing the sealing body 50 is not particularly limited. For example, the semiconductor wafer can be separated into pieces by the same method as that used for dicing the semiconductor wafer. The step of individualizing the sealing body 50 may be carried out in a state where the sealing body 50 is attached to a dicing sheet or the like. By separating the encapsulant 50 into individual pieces, a semiconductor package for each semiconductor chip CP is manufactured, and this semiconductor package is mounted on a printed wiring board or the like in the mounting process.

(Effect of this embodiment)
In the present embodiment, the surface free energy of 10 mJ / ^{m 2} or more, the use of the adhesive sheet 10 provided with a pressure-sensitive adhesive layer 12 is 22 mJ / ^{m 2} or less, to seal the semiconductor chip CP on the adhesive sheet 10 Excellent filling property.
Therefore, according to the present embodiment, in the sealing step, as shown in FIG. 3, the sealing resin 30 is formed between the stepped portion CPB on the peripheral edge of the circuit surface CPA of the semiconductor chip CP and the pressure-sensitive adhesive layer 12. The gap S can be embedded.
The height dimension x of the step between the step portion CPB and the circuit surface CPA is usually 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 5 μm or less. The smaller the height dimension x, the more difficult it is for the sealing resin 30 to embed the gap S, but if it is at least the above lower limit, the sealing resin 30 can embed the gap S.
The width dimension y of the stepped portion CPB is usually 1 μm or more and 100 μm or less, preferably 5 μm or more and 50 μm or less. The larger the width dimension y, the more difficult it is for the sealing resin 30 to embed the gap S, but if it is equal to or less than the upper limit, the sealing resin 30 can embed the gap S.

[Modification of Embodiment]
The present invention is not limited to the above-described embodiment, and modifications and improvements within the range in which the object of the present invention can be achieved are included in the present invention. In the following description, if the members and the like described in the above embodiment are the same, the same reference numerals are given and the description thereof will be omitted or simplified.

In the above embodiment, the mode in which the pressure-sensitive adhesive layer 12 of the pressure-sensitive adhesive sheet 10 is covered with the release sheet RL has been described as an example, but the present invention is not limited to such a mode.
Further, the pressure-sensitive adhesive sheet 10 may be a single leaf, or may be provided in a state in which a plurality of pressure-sensitive adhesive sheets 10 are laminated. In this case, for example, the pressure-sensitive adhesive layer 12 may be covered with the base material 11 of another pressure-sensitive adhesive sheet to be laminated.
Further, the adhesive sheet 10 may be a long sheet, or may be provided in a rolled state. The adhesive sheet 10 wound up in a roll shape can be used by being unwound from the roll and cut into a desired size.

In the above embodiment, the case where the sealing resin 30 is made of a thermosetting resin has been described as an example, but the present invention is not limited to such an embodiment. For example, the sealing resin 30 may be an energy ray-curable resin that is cured by energy rays such as ultraviolet rays.
In the above-described embodiment, in the description of the method for manufacturing the semiconductor device, the mode in which the frame member 20 is attached to the pressure-sensitive adhesive sheet 10 has been described as an example, but the present invention is not limited to such a mode. The adhesive sheet 10 may be used in a method for manufacturing a semiconductor device that seals a semiconductor element without using the frame member 20.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples.

〔Evaluation method〕
The evaluation of the adhesive sheet was performed according to the method shown below.

[Surface free energy and contact angle]
The surface free energy of the pressure-sensitive adhesive layer was measured by the following method. Specifically, first, the contact angles of water, diiodomethane, and 1-bromonaphthalene with respect to the pressure-sensitive adhesive layer were measured using a contact angle measuring device (“DM701” manufactured by Kyowa Surface Chemistry Co., Ltd.). The amount of each droplet was 2 μL. Then, the surface free energy was calculated from these measured values by the Kitazaki-Hata method.

[Filling property evaluation]
Semiconductor chip on the adhesive surface of the adhesive sheet (silicon chip with mirror finish, chip size: 2.3 mm x 1.7 mm, chip thickness: 0.2 mm, height dimension of the step between the step and the circuit surface x: 8000 pieces (1 μm, width dimension y: 30 μm) of the step portion are installed at intervals of 5 mm so that the adhesive surface of the adhesive sheet and the circuit surface of the semiconductor chip are in contact with each other. After that, the semiconductor chip on the adhesive sheet is sealed with a sealing resin (ABF film manufactured by Ajinomoto Fine-Techno Co., Ltd., GX LE-T15B) using a vacuum heating and pressurizing laminator (“7024HP5” manufactured by ROHM and HAAS). Stopped (sealing process). The sealing conditions are as follows.
・ Preheating temperature: 100 ° C for both table and diaphragm
-Vacuation: 60 seconds-Dynamic press mode: 30 seconds-Static press mode: 10 seconds Then, observe the semiconductor chips on the adhesive sheet after the sealing process with a microscope (around the entire circumference of each semiconductor chip) and semiconductor. It was confirmed whether or not the sealing resin was embedded in the gap between the stepped portion of the chip and the adhesive layer. The case where the sealing resin was embedded in the gap was determined as "A", and the case where the sealing resin was not embedded in the gap or the void was generated in the gap was determined as "B".

[Preparation of adhesive sheet]
(Example 1)

(1) Preparation of Adhesive Layer The following materials (polymer, adhesive aid, cross-linking agent, and diluting solvent) are blended, sufficiently stirred, and the adhesive liquid for coating (adhesive composition) according to Example 1. ) Was prepared.

-Polymer: Acrylic ester copolymer, 40 parts by mass (solid content)
The acrylic acid ester copolymer was prepared by copolymerizing 92.8% by mass of 2-ethylhexyl acrylate, 7.0% by mass of 2-hydroxyethyl acrylate, and 0.2% by mass of acrylic acid.

-Adhesive aid: Hydroxyl-terminated polybutadiene at both ends [manufactured by Nippon Soda Corporation; GI-1000], 5 parts by mass

-Crosslinking agent: Aliphatic isocyanate having hexamethylene diisocyanate (isocyanurate-type modified hexamethylene diisocyanate) [manufactured by Nippon Polyurethane Industry Co., Ltd .; Coronate HX], 3.5 parts by mass (solid content)

-Diluting solvent: Methyl ethyl ketone was used, and the solid content concentration of the pressure-sensitive adhesive solution for coating was adjusted to 30% by mass.

(2) Preparation of Adhesive Layer 38 μm transparent polyethylene terephthalate provided with a silicone-based release layer so that the prepared adhesive liquid for coating is dried using a comma coater (registered trademark) to a film thickness of 50 μm. The film was applied to the release layer surface side of the film release film [Lintec Co., Ltd .; SP-PET382150] and heated at 90 ° C. and 90 seconds, followed by heating at 115 ° C. and 90 seconds to dry the coating film. ..

(3) Preparation of Adhesive Sheet After drying the coating film of the pressure-sensitive adhesive liquid for coating, the pressure-sensitive adhesive layer and the base material were bonded to obtain the pressure-sensitive adhesive sheet according to Example 1. As the base material, a transparent polyethylene terephthalate film [manufactured by Teijin DuPont Film Co., Ltd .; PET50KFL12D, thickness 50 μm, storage elastic modulus at 100 ° C. 3.1 × 10 ⁹ Pa] was used, and the film adhered to one surface of the base material. The agent layers were laminated.

(Example 2)
The pressure-sensitive adhesive sheet according to Example 2 was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was different.
In Example 2, the pressure-sensitive adhesive liquid for coating was applied to a base material so that the thickness after drying was 20 μm, and dried to prepare a pressure-sensitive adhesive layer.

(Example 3)
In Example 3, a silicone-based adhesive was used.
In Example 3,
Silicone adhesive A (SD4580PSA) 18 parts by mass (solid content),
Silicone adhesive B (SD4587L) 40 parts by mass (solid content),
Catalyst A (NC-25 CAT) 0.3 parts by mass (solid content),
0.65 parts by mass (solid content) of catalyst B (CAT-SRX-212) and 5 parts by mass (solid content) of primer (BY24-712) are blended, and toluene is used as a diluting solvent to increase the solid content by 20% by mass. The adhesive solution for coating (adhesive composition) was prepared by diluting the mixture so as to be the same and stirring thoroughly. The materials used in the pressure-sensitive adhesive composition of Example 3 are all manufactured by Toray Dow Corning Co., Ltd.
The coating pressure-sensitive adhesive liquid according to Example 3 was applied to a base material using a comma coater (registered trademark) so that the thickness after drying was 20 μm, and dried to prepare a pressure-sensitive adhesive layer. A release film [manufactured by Lintec Co., Ltd .: SP-PET38E-0010YCS] made of 38 μm transparent polyethylene terephthalate provided with the above was bonded. The drying conditions were 130 ° C. and 2 minutes. As the base material used in Example 2, a polyimide film [manufactured by Toray DuPont Co., Ltd .; Kapton 100H, thickness 25 μm, storage elastic modulus at 100 ° C. 3.1 × 10 ⁹ Pa] was used.

(Comparative Example 1)
The pressure-sensitive adhesive sheet according to Comparative Example 1 was produced in the same manner as in Example 1 except that the polymer contained in the pressure-sensitive adhesive layer was different from that in Example 1.
-Polymer: Acrylic ester copolymer, 40 parts by mass (solid content)
The acrylic acid ester copolymer contains 80.8% by mass of 2-ethylhexyl acrylate, 7% by mass of 2-hydroxyethyl acrylate, 12% by mass of 4-acryloyl morpholine, and 0.2% by mass of acrylic acid. Prepared by polymerization.

(Comparative Example 2)
The pressure-sensitive adhesive sheet according to Comparative Example 2 was produced in the same manner as in Comparative Example 1 except that the thickness of the pressure-sensitive adhesive layer was different.
In Comparative Example 2, the pressure-sensitive adhesive liquid for coating was applied and dried on the substrate so that the thickness after drying was 20 μm to prepare a pressure-sensitive adhesive layer.

(Comparative Example 3)
The pressure-sensitive adhesive sheet according to Comparative Example 1 was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive composition was different from that in Example 1.
-Polymer: Acrylic ester copolymer, 40 parts by mass (solid content)
The acrylic acid ester copolymer was prepared by copolymerizing 92.8% by mass of lauryl acrylate, 7% by mass of 2-hydroxyethyl acrylate, and 0.2% by mass of acrylic acid.
Adhesive aid: Hydroxyl-terminated polybutadiene at both ends [manufactured by Nippon Soda Co., Ltd .; GI-1000], 5 parts by mass-Crosslinking agent: Aliphatic isocyanate having hexamethylene diisocyanate (isocyanurate-type modified hexamethylene diisocyanate) [Manufactured by Nippon Polyurethane Industry Co., Ltd .; Coronate HX], 9.9 parts by mass (solid content)
-Diluting solvent: Methyl ethyl ketone was used, and the solid content concentration of the pressure-sensitive adhesive solution for coating was adjusted to 30% by mass.

Table 1 shows the evaluation results of the pressure-sensitive adhesive sheets according to Examples 1 to 3 and Comparative Examples 1 to 3. Table 1 shows the adhesives used in Examples 1 to 3 and Comparative Examples 1 to 3.

Table As is apparent from 1 to show the result, in the case where the surface free energy of the pressure-sensitive adhesive layer is 10 mJ / ^{m 2} or more 22 mJ / ^{m 2} or less (Examples 1 to 3), the semiconductor device on the adhesive sheet It was confirmed that the filling property at the time of sealing was excellent.

10 ... Adhesive sheet, 11 ... Base material, 12 ... Adhesive layer.

Claims (7)

An adhesive sheet used for sealing a semiconductor element on an adhesive sheet.
The pressure-sensitive adhesive sheet comprises a base material and a pressure-sensitive adhesive layer.
The pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive composition and contains
The acrylic pressure-sensitive adhesive composition is a ternary acrylic copolymer obtained by copolymerizing 2-ethylhexyl acrylate, acrylic acid and a hydroxyl group-containing monomer.
The proportion of the copolymer component derived from 2-ethylhexyl acrylate in the acrylic copolymer is 80% by mass or more and 95% by mass or less, and the proportion of the mass of the copolymer component derived from acrylic acid is 1% by mass or less. The balance is a copolymer component derived from a hydroxyl group-containing monomer.
The surface free energy of the pressure-sensitive adhesive layer is 10 mJ / ^{m 2} or more 22 mJ / ^{m 2} or less,
Adhesive sheet. An adhesive sheet used for sealing a semiconductor element on an adhesive sheet.
The pressure-sensitive adhesive sheet comprises a base material and a pressure-sensitive adhesive layer.
The pressure-sensitive adhesive layer contains an addition-reaction type silicone-based pressure-sensitive adhesive composition.
The addition reaction type silicone-based pressure-sensitive adhesive composition contains a main agent composed of a mixture of a silicone resin component and a silicone rubber component, and a cross-linking agent containing a hydrosilyl group.
The surface free energy of the pressure-sensitive adhesive layer is 10 mJ / ^{m 2} or more 22 mJ / ^{m 2} or less,
Adhesive sheet. The contact angle of 1-bromonaphthalene with respect to the pressure-sensitive adhesive layer is 65 ° or more.
The adhesive sheet according to claim 1 or 2 . A storage modulus at 100 ° C. of the substrate is 1 × ¹⁰ 7 Pa or more,
The adhesive sheet according to any one of claims 1 to 3 . The thickness of the pressure-sensitive adhesive layer is 5 μm or more and 60 μm or less.
The adhesive sheet according to any one of claims 1 to 4 . The thickness of the pressure-sensitive adhesive layer is 10 μm or more and 50 μm or less.
The adhesive sheet according to any one of claims 1 to 5 . The pressure-sensitive adhesive sheet is peeled off from the semiconductor element after sealing the semiconductor element.
The adhesive sheet according to any one of claims 1 to 6 .

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