JP2018098228A - Protection tape, and method for manufacturing semiconductor device by use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection tape which enables the achievement of good heat resistance and solderability, and a method for manufacturing a semiconductor device by use of the protection tape.SOLUTION: A protection tape 10 comprises an adhesive layer 11, a first thermoplastic resin layer 12, a second thermoplastic resin layer 13, and a base film layer 14 in this order. The amount of crosslinkable groups of the second thermoplastic resin layer, which is represented by the formula (1) below is 0.01-3%, and the requirement given by the expression (2) below is satisfied. (1) Amount of crosslinkable groups(%)=(pmr/pmw×(pmf-1))/(Σ(mr/mw))×100; and (2)Gn/Ga≤0.01.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a protective tape used for manufacturing a semiconductor device and a method for manufacturing a semiconductor device using the same.

  In a method of manufacturing a semiconductor device using a semiconductor wafer, a back grind tape is used for the purpose of protecting the bump forming surface in a process of grinding the opposite surface of the wafer on which a plurality of bumps (projection electrodes) are formed. A so-called protective tape is used.

  As a conventional protective tape, for example, a thermosetting resin for imparting a bump reinforcing function, such as a semiconductor wafer surface protective sheet described in Patent Document 1 and a semiconductor bonding adhesive sheet described in Patent Document 2. The thing which laminated | stacked the layer is mentioned.

International Publication No. 2011/152045 International Publication No. 2015/064574

  For example, when the adhesive sheet for semiconductor bonding described in Patent Document 2 is laminated on a wafer, a thermosetting resin tends to remain on the bumps, and this resin may hinder solder bonding during subsequent mounting. Further, for example, when the thermosetting resin is bonded to the semiconductor wafer surface protection sheet described in Patent Document 1 and laminated, there is a similar problem. In addition to solderability, it is desired to improve heat resistance. For example, when a protective tape having an adhesive layer, a thermoplastic resin layer, and a base film layer is applied to a wafer and the adhesive layer is thermoset, the resin of the thermoplastic resin layer protrudes from the base film. It is desired to suppress it.

  The present technology has been proposed in view of such a conventional situation, and provides a protective tape capable of improving heat resistance and solderability, and a method of manufacturing a semiconductor device using the same.

The protective tape according to the present technology includes an adhesive layer, a first thermoplastic resin layer, a second thermoplastic resin layer, and a base film layer in this order. The amount of the crosslinking group represented by the following formula (1) is 0.01 to 3%, which satisfies the condition of the following formula (2).
(1) Amount of crosslinking group (%) = (pmr / pmw × (pmf−1)) / (Σ (mr / mw)) × 100
(2) Gn / Ga <0.01
(In formula (1), pmr is the ratio of the polyfunctional monomer used in the second thermoplastic resin layer, pmw is the molecular weight of the polyfunctional monomer, pmf is the number of functional groups of the polyfunctional monomer, and mr is The ratio of each monomer used in the second thermoplastic resin layer, mw is the molecular weight of each monomer, and in formula (2), Gn is the storage shear modulus of the adhesive layer at the application temperature at which the protective tape is applied. Ga is the storage shear modulus of the first thermoplastic resin layer at the application temperature.)

  In addition, in the method of manufacturing a semiconductor device according to the present technology, a step (A) of attaching a protective tape to a wafer surface on which bumps are formed, and a step (B) of grinding the opposite surface of the wafer to which the protective tape is attached. And a step of curing the adhesive layer (C), a step of applying an adhesive tape to the grinded surface (D), a step of removing the protective tape leaving the adhesive layer and removing other layers (E And a step (F) of dicing the wafer to which the adhesive tape is attached to obtain individual semiconductor chips.

  According to the present technology, heat resistance and solderability can be improved.

FIG. 1 is a cross-sectional view schematically showing a protective tape. FIG. 2 is a cross-sectional view showing an outline of the protective tape attaching step (A). FIG. 3 is a cross-sectional view schematically showing the grinding process (B). FIG. 4 is a cross-sectional view showing an outline of the curing step (C). FIG. 5 is a cross-sectional view showing an outline of the adhesive tape attaching step (D). FIG. 6 is a cross-sectional view schematically showing the protective tape peeling step (E). FIG. 7 is a cross-sectional view showing an outline of the dicing process (F). FIG. 8 is a cross-sectional view schematically showing the expanding step (G). FIG. 9 is a cross-sectional view showing an outline of the pickup process (H). FIG. 10 is a cross-sectional view schematically showing the mounting process (I).

<1. Protective tape>
FIG. 1 is a cross-sectional view schematically showing a protective tape. The protective tape 10 is called a back grind tape, and protects the wafer from scratches, cracks, contamination, and the like, for example, in a grinding step (B) of a semiconductor device manufacturing method described later. The protective tape 10 includes, for example, an adhesive layer 11, a first thermoplastic resin layer 12, a second thermoplastic resin layer 13, and a base film layer 14 in this order. Moreover, the amount of crosslinking groups represented by following formula (1) of the 2nd thermoplastic resin layer 13 is 0.01 to 3%, and the masking tape 10 satisfy | fills the conditions of following formula (2).
(1) Crosslinkable group amount (%) = (pmr / pmw × (pmf−1)) / (Σ (mr / mw)) × 100
(2) Gn / Ga <0.01
(In the formula (1), pmr is the ratio of the polyfunctional monomer used in the second thermoplastic resin layer 13, pmw is the molecular weight of the polyfunctional monomer, pmf is the number of functional groups of the polyfunctional monomer, mr Is the ratio of each monomer used in the second thermoplastic resin layer 13. mw is the molecular weight of each monomer, where Gn is the adhesive layer 11 at the application temperature at which the protective tape 10 is applied. (It is a storage shear modulus, and Ga is the storage shear modulus of the first thermoplastic resin layer 12 at the application temperature at which the protective tape 10 is applied.)

  In the protective tape 10, the amount of the crosslinking group represented by the formula (1) of the second thermoplastic resin layer 13 is 0.01 to 3%. That is, the amount of the cross-linking group of each polyfunctional monomer in all the monomers (monofunctional monomer containing one functional group and polyfunctional monomer containing two or more functional groups) used in the second thermoplastic resin layer 13. The total may be 0.01 to 3%.

  By setting the amount of the crosslinking group represented by the formula (1) of the second thermoplastic resin layer 13 to 0.01% or more, for example, when the adhesive layer 11 is thermally cured in the curing step (C) described later, The degree of cross-linking of the second thermoplastic resin layer 13 can be adjusted to such an extent that the resin of the thermoplastic resin layer 13 can be prevented from sticking out of the base film 14 and adhering to the wafer. Therefore, after the adhesive layer 11 is cured, the layers constituting the protective tape 10 other than the adhesive layer 11 (the first thermoplastic resin layer 12, the second thermoplastic resin layer 13 and the base film layer 14). Can be easily peeled off. That is, the peelability of the protective tape 10 can be improved.

  When the amount of the crosslinking group represented by the formula (1) of the second thermoplastic resin layer 13 is 3% or less, for example, when the protective tape 10 is applied to the wafer in the protective tape application step (A) described later. The degree of crosslinking of the second thermoplastic resin layer 13 can be adjusted to such an extent that the generation of voids between the bumps of the adhesive layer 11 can be suppressed. Therefore, the embedding property of the bump can be improved. Thus, the heat resistance of the protective tape 10 is good when the amount of the crosslinking group represented by the formula (1) of the second thermoplastic resin layer 13 is 0.01% to 3% or less. Can be.

  Further, the protective tape 10 satisfies the condition of the above formula (2). That is, the protective tape 10 has the storage shear elastic modulus (Gn) of the adhesive layer 11 at the application temperature at which the protective tape 10 is applied, and the storage shear of the first thermoplastic resin layer 12 at the application temperature at which the protective tape 10 is applied. The ratio (Gn / Ga) to the elastic modulus (Ga) is less than 0.01. By satisfying the condition of the expression (2), the deformation and flow of the adhesive layer 11 are very good as compared with the first thermoplastic resin layer 12. Thereby, when sticking the protective tape 10 on a wafer, adhesion of the adhesive layer 11 onto the bumps of the wafer can be more effectively suppressed, and the adhesive layer 11 is less likely to remain on the bumps. Therefore, solderability can be improved.

  The lower limit of the value (Gn / Ga) on the left side of the formula (2) is preferably 0.0005 or more, and more preferably 0.001 or more.

  As described above, the protective tape 10 has the adhesive layer 11, the first thermoplastic resin layer 12, the second thermoplastic resin layer 13, and the base film layer 14 in this order, and the second The amount of the crosslinking group represented by the formula (1) of the thermoplastic resin layer 13 is 0.01 to 3%, and further satisfies the condition of the formula (2). When the amount of the crosslinking group represented by the formula (1) of the second thermoplastic resin layer 13 is 0.01 to 3%, the heat resistance of the protective tape 10 can be improved. Moreover, soldering bondability can be made favorable when the masking tape 10 satisfy | fills the conditions of Formula (2). Accordingly, the use of the protective tape 10 can improve heat resistance and solderability.

  The protective tape 10 further has a storage shear modulus (Ga) of the first thermoplastic resin layer 12 at the application temperature at which the protective tape 10 is applied, so that the second thermoplastic resin layer 13 at the application temperature at which the protective tape 10 is applied. It is preferable that it is larger than the storage shear elastic modulus (Gb). By setting it as such a structure, since the surface layer of the adhesive bond layer 11, ie, the 1st thermoplastic resin layer 12, becomes harder than the 2nd thermoplastic resin layer 13, the 1st thermoplastic resin layer 12 is When deformed, the second thermoplastic resin layer 13 is less likely to inhibit the deformation of the first thermoplastic resin layer 12.

The protective tape 10 preferably further satisfies the condition of the formula (3).
(3) Ga>Gb> Gn
(In Formula (3), Gb is the storage shear elastic modulus of the 2nd thermoplastic resin layer 13 in the sticking temperature which sticks the masking tape 10, and Gn and Ga are synonymous with Gn and Ga in Formula (2). is there.)

  That is, the storage shear elastic modulus (Ga) of the first thermoplastic resin layer 12 at the application temperature at which the protective tape 10 is applied is the largest, and the second thermoplastic resin layer 13 at the application temperature at which the protective tape 10 is applied. It is preferable that the storage shear elastic modulus (Gb) is the second largest and the storage shear elastic modulus (Gn) of the adhesive layer 11 at the application temperature at which the protective tape 10 is applied is the third largest. By satisfying the condition of the formula (3), the adhesive layer 11, the second thermoplastic resin layer 13, and the first thermoplastic resin layer 12 are hardened in this order, and therefore, compared with the first thermoplastic resin layer 12. The deformation and flow of the adhesive layer 11 are very good. Thereby, when sticking the protective tape 10 on the wafer, adhesion of the adhesive layer 11 on the bumps of the wafer can be more effectively suppressed, and the adhesive layer 11 is less likely to remain on the bumps. The solderability can be improved.

Moreover, it is preferable that the thickness (Tb) of the 2nd thermoplastic resin layer 13 is larger than the thickness (Ta) of the 1st thermoplastic resin layer 12, and the masking tape 10 satisfy | fills the conditions of Formula (4). It is more preferable.
(4) Tn <Ta <Tb
(In Formula (4), Tn is the thickness of the adhesive layer 11, Ta is the thickness of the first thermoplastic resin layer 12, and Tb is the thickness of the second thermoplastic resin layer 13.)

  That is, in the protective tape 10, the thickness (Tb) of the second thermoplastic resin layer 13 is the largest, the thickness (Ta) of the first thermoplastic resin layer 12 is the second largest, and the thickness of the adhesive layer 11. It is preferable that (Tn) is the third largest.

  Hereinafter, the structural example of each layer which comprises the protective tape 10 is demonstrated.

[Adhesive layer 11]
The storage shear modulus (Gn) at 60 ° C. of the adhesive layer 11 is, for example, 1.0E + 01 Pa to 5.0E + 04 Pa from the range of the storage shear modulus (Ga) of the first thermoplastic resin layer 12 described later. It is preferable that it is 1.0E + 02Pa-3.5E + 03Pa. By setting the storage shear modulus of the adhesive layer 11 to 1.0E + 01 Pa or more, the bump adheres to the adhesive layer 11 while the bump penetrates the adhesive layer 11, and the bump layer covers the tip of the bump. Can be suppressed. Moreover, it can suppress that resin of the adhesive bond layer 11 flows, when the protective tape 10 is affixed on a wafer. Moreover, by setting the storage shear elastic modulus of the adhesive layer 11 to 5.0E + 04 Pa or less, the bumps can penetrate the adhesive layer 11 more easily, and conduction can be improved.

  The resin composition of the adhesive layer 11 is not particularly limited. For example, a thermosetting type such as a thermal anion curable type, a thermal cation curable type, a thermal radical curable type, a photo cation curable type, a photo radical curable type or the like. It is possible to use a mold, or a thermo / photo-curing type which is used in combination to substantially the same.

  Here, a thermosetting adhesive composition containing a film-forming resin, an epoxy resin, a curing agent, a curing aid, and an inorganic filler will be described as the adhesive layer 11.

  Various resins such as a phenoxy resin, an epoxy resin, a modified epoxy resin, and a urethane resin can be used as the film forming resin. These film forming resins may be used alone or in combination of two or more. Among these, phenoxy resin is preferably used from the viewpoint of film formation state, connection reliability, and the like.

  Examples of the epoxy resin include dicyclopentadiene type epoxy resin, glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, spiro ring type epoxy resin, Naphthalene type epoxy resin, biphenyl type epoxy resin, terpene type epoxy resin, tetrabromobisphenol A type epoxy resin, cresol novolac type epoxy resin, phenol novolak type epoxy resin, α-naphthol novolak type epoxy resin, brominated phenol novolak type epoxy resin And so on. These epoxy resins may be used alone or in combination of two or more. Among these, a dicyclopentadiene type epoxy resin is preferably used from the viewpoint of high adhesion and heat resistance.

  Examples of the curing agent include novolak-type phenol resins, aliphatic amines, aromatic amines, acid anhydrides, and the like. These curing agents may be used alone or in combination of two or more. May be. Among these, a novolak type phenol resin is preferably used from the viewpoint of the crosslink density of the cured product.

  Curing aids include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 1,8-diazabicyclo (5,4,0) undecene-7 salt (DBU salt) ), Tertiary amines such as 2- (dimethylaminomethyl) phenol, phosphines such as triphenylphosphine, and metal compounds such as tin octylate. Among these, 2-ethyl-4-methylimidazole is preferable.

  Moreover, you may make it mix | blend suitably with pigments, such as inorganic fillers, silane coupling agents, elastomers, such as acrylic rubber, and carbon black, as other components, in an adhesive composition.

Examples of the inorganic filler include silica, aluminum nitride, and alumina. An inorganic filler may be used individually by 1 type, or may use 2 or more types together. The inorganic filler is preferably surface-treated, and is preferably a hydrophilic inorganic filler. Examples of the hydrophilic inorganic filler include those obtained by surface-treating an inorganic filler with a hydrophilic surface treatment agent. Examples of hydrophilic surface treatment agents include silane coupling agents, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , silicone, and stearic acid. Aluminum etc. are mentioned, A silane coupling agent is preferable.

  The thickness of the adhesive layer 11 is preferably 10 to 80% of the height of the bump formed on the wafer, and more preferably 10 to 60%. By making the height 10% or more of the bump height, it becomes easier to obtain the effect of reinforcing the bump. Moreover, the adhesive layer 11 can penetrate a bump more easily by setting it as 80% or less of the height of a bump. For example, when the height of the bump formed on the wafer is 100 to 200 μm, the thickness of the adhesive layer 11 is preferably 5 to 100 μm, and more preferably 5 to 30 μm.

[First thermoplastic resin layer 12]
The first thermoplastic resin layer 12 is made of, for example, ethylene vinyl acetate copolymer (EVA), polyethylene, polypropylene, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, fluororesin, polyphenylene sulfide, polystyrene, ABS. It is a layer made of a resin such as resin, acrylic resin, polycarbonate, polyurethane, polyvinyl chloride, polyphenylene oxide. The said resin may be used individually by 1 type, and may use 2 or more types together.

  The storage shear modulus (Ga) at 60 ° C. of the first thermoplastic resin layer 12 is preferably 1.0E + 06 Pa to 1.0E + 09 Pa, more preferably 1.0E + 06 Pa to 1.0E + 07 Pa. More preferably, it is 0.0E + 06 Pa to 6.0E + 06 Pa.

  The thickness (Ta) of the first thermoplastic resin layer 12 preferably satisfies the above-mentioned (4) from the thickness range of the adhesive layer 11 and the second thermoplastic resin layer 13, for example, 10 to 200 μm. It is preferable that

[Second thermoplastic resin layer 13]
The second thermoplastic resin layer 13 is formed so as to be in contact with the first thermoplastic resin layer 12.

  The storage shear modulus (Gb) at 60 ° C. of the second thermoplastic resin layer 13 preferably satisfies the condition of the above-described formula (3), and can be set to, for example, 1.0E + 04 Pa to 2.0E + 06 Pa. 1.0E + 04 Pa to 3.0E + 04 Pa.

  The thickness (Tb) of the second thermoplastic resin layer 13 is preferably in a range satisfying the above-described formula (4), and can be set to 100 to 700 μm, for example.

  The second thermoplastic resin layer 13 is a composition in which the total content of polyfunctional monomers is 0.01 to 5% by mass in consideration of the range of the amount of the crosslinking group represented by the above-described formula (1). It is preferable that is cured. For example, the second thermoplastic resin composition layer 13 is a composition containing a monofunctional monomer and a bifunctional monomer, and the content of the bifunctional monomer is 0.01 to 5% by mass. It is preferable that is cured.

  The type of the polyfunctional monomer may be bifunctional, trifunctional, tetrafunctional or more as long as it satisfies the range of the cross-linking group amount represented by the above-described formula (1). Good. Two or more polyfunctional monomers may be used in combination. For example, a bifunctional monomer and a trifunctional monomer may be used in combination, or two or more types of bifunctional monomers may be used in combination.

  The lower limit of the molecular weight of the polyfunctional monomer may be 200 or more, for example, or 300 or more. Further, the upper limit value of the molecular weight of the polyfunctional monomer may be 600 or less, for example.

  The polyfunctional monomer is not particularly limited as long as it satisfies the range of the crosslinking group amount represented by the above-described formula (1), and a commercially available product can be used. Examples of the bifunctional monomer include bifunctional (meth) acrylates, such as KAYARAD NPGDA, PEG400DA, FM-400, R-167, HX-220, HX-620, R-620, R-551, R-712. R-604, R-684 (manufactured by Nippon Kayaku Co., Ltd.) and the like. Examples of the trifunctional monomer include trifunctional (meth) acrylates such as KAYARAD GPO-303, TMPTA (manufactured by Nippon Kayaku Co., Ltd.), and the like.

[Base film layer 14]
As the substrate film layer 14, a porous substrate made of a plastic film such as polyethylene terephthalate, polyethylene, polypropylene, or polyester, paper, cloth, nonwoven fabric, or the like can be used.

  The thickness of the base film layer 14 is preferably 25 to 200 μm, and more preferably 50 to 100 μm.

  In addition, the protective tape 10 is not limited to the above-described configuration, and other layers may be formed between the surface of each layer and between adjacent layers as long as the effects of the present technology are not impaired.

  The protective tape 10 is, for example, bonded to a laminate of a base film layer and a thermoplastic resin layer in which a base film layer, a first thermoplastic resin layer, and a second thermoplastic resin layer are formed in this order. It can be obtained by laminating the agent layer. The laminated body of the base film layer and the thermoplastic resin layer is, for example, a first thermoplastic resin obtained by applying a second thermoplastic resin layer to the base film layer and curing it with ultraviolet rays, and then extruding and molding it in advance. Obtained by laminating the layers. The adhesive layer can be obtained, for example, by preparing the thermosetting adhesive composition described above, applying the adhesive composition to the release-treated substrate using a bar coater, and drying the adhesive composition.

<2. Manufacturing Method of Semiconductor Device>
Next, an example of a method for manufacturing a semiconductor device using the above-described protective tape 10 will be described. This manufacturing method includes a step (A) of applying a protective tape to the wafer surface on which bumps are formed, a step (B) of grinding the opposite surface of the wafer to which the protective tape is applied, and a step of curing the adhesive layer. The step (C), the step (D) of applying the adhesive tape to the grinded surface, the step (E) of removing the protective tape leaving the adhesive layer and removing the other layer, and the adhesive tape are applied And dicing the wafer to obtain individual semiconductor chips (F). Furthermore, this manufacturing method has an expanding process (G), a pick-up process (H), and a mounting process (I).

[Protective tape application process (A)]
FIG. 2 is a cross-sectional view showing an outline of the protective tape attaching step (A). In the protective tape attaching step (A), the protective tape 10 is attached to the surface of the wafer 21 on which the bumps 22 are formed. The application temperature for applying the protective tape 10 is preferably 25 ° C. to 100 ° C., more preferably 40 ° C. to 80 ° C., from the viewpoints of reducing voids, improving wafer adhesion, and preventing wafer warpage after wafer grinding.

  The wafer 21 has an integrated circuit formed on a semiconductor surface such as silicon and bumps 22 for connection. The thickness of the wafer 21 is not particularly limited, but is preferably 200 to 1000 μm.

  The bump 22 is not particularly limited, and examples thereof include a low melting point bump or a high melting point bump made of solder, a tin bump, a silver-tin bump, a silver-tin-copper bump, a gold bump, and a copper bump. Moreover, it is preferable that the height of the bump 22 is, for example, 10 to 200 μm.

  The protective tape 10 is bonded together in a state where the formation surface of the bump 22 and the adhesive layer 11 are in contact with each other. As shown in FIG. 2, the bump 22 penetrates the adhesive layer 11 and is embedded in the first thermoplastic resin layer 12. Further, the surface of the first thermoplastic resin layer 12 in contact with the second thermoplastic resin 13 is deformed so as to follow the shape of the bump 22. Further, the surface of the second thermoplastic resin layer 13 that contacts the first thermoplastic resin layer 12 is deformed so as to follow the deformation of the first thermoplastic resin layer 12.

[Grinding process (B)]
FIG. 3 is a cross-sectional view schematically showing the grinding process (B). In the grinding step (B), the opposite surface of the wafer 21 to which the protective tape 10 is attached, that is, the surface opposite to the surface on which the bumps 22 are formed, is fixed to a grinding device for polishing. Polishing is usually performed until the thickness of the wafer 21 reaches 50 to 600 μm. However, in the present embodiment, the bumps 22 are reinforced by the adhesive layer 11, so that the wafer 21 may be polished to a thickness of 50 μm or less.

[Curing step (C)]
FIG. 4 is a cross-sectional view showing an outline of the curing step (C). In the curing step (C), the adhesive layer 11 of the protective tape 10 is cured. As a curing method and curing conditions, a known method for curing a thermosetting adhesive can be used. For example, the curing conditions are preferably 100 to 200 ° C. for 1 hour or longer.

[Adhesive tape application process (D)]
FIG. 5 is a cross-sectional view showing an outline of the adhesive tape attaching step (D). In the adhesive tape attaching step (D), the adhesive tape 30 is attached to the grinding surface of the wafer 21. The adhesive tape 30 is called a dicing tape, and is a tape for protecting and fixing the wafer 21 in the dicing step (F) and holding it until the pickup step (H).

  The adhesive tape 30 is not specifically limited, A well-known thing can be used. In general, the pressure-sensitive adhesive tape 30 includes a pressure-sensitive adhesive layer 31 and a base film layer 32. Examples of the pressure-sensitive adhesive layer 31 include polyethylene-based, acrylic-based, rubber-based, and urethane-based pressure-sensitive adhesives. As the base film layer 32, a plastic base film made of polyethylene terephthalate, polyethylene, polypropylene, polyester, or a porous base material made of paper, cloth, nonwoven fabric, or the like can be used. Moreover, it does not specifically limit as an adhesive tape sticking apparatus and conditions, A well-known apparatus and conditions can be used.

[Protective tape peeling process (E)]
FIG. 6 is a cross-sectional view schematically showing the protective tape peeling step (E). In the protective tape peeling step (E), the protective tape 10 is peeled off leaving the adhesive layer 11 and the other layers are removed. That is, the first thermoplastic resin layer 12, the second thermoplastic resin layer 13, and the base film layer 14 are removed, and only the adhesive layer 11 remains on the wafer 21.

[Dicing process (F)]
FIG. 7 is a cross-sectional view showing an outline of the dicing process (F). In the dicing process (F), the wafer 21 to which the adhesive tape 30 is attached is diced to obtain individual semiconductor chips. The dicing method is not particularly limited, and a known method such as cutting the wafer 21 with a dicing saw can be used.

[Expanding process (G)]
FIG. 8 is a cross-sectional view schematically showing the expanding step (G). In the expanding step (G), for example, the adhesive tape 30 to which a plurality of divided semiconductor chips are attached is elongated in the horizontal direction to widen the intervals between the individual semiconductor chips.

[Pickup process (H)]
FIG. 9 is a cross-sectional view showing an outline of the pickup process (H). In the pick-up step (H), the semiconductor chip adhered and fixed on the adhesive tape 30 is pushed up from the lower surface of the adhesive tape 30 and peeled off, and the peeled semiconductor chip is adsorbed by a collet. The picked-up semiconductor chip is stored in a chip tray or conveyed to a chip mounting nozzle of a flip chip bonder.

[Mounting process (I)]
FIG. 10 is a cross-sectional view schematically showing the mounting process (I). In the mounting step (I), for example, the semiconductor chip and the circuit board are connected using a circuit connecting material such as NCF (Non Conductive Film). Although it does not specifically limit as a circuit board, Plastic substrates, such as a polyimide substrate and a glass epoxy substrate, a ceramic substrate, etc. can be used. Moreover, as a connection method, the well-known method using a heating bonder, a reflow furnace, etc. can be used.

  As described above, according to this manufacturing method, when the protective tape 10 is applied to the wafer 21 in the protective tape application step (A), the adhesion of the adhesive layer 11 onto the bumps 22 of the wafer 21 is more effective. The adhesive layer 11 is less likely to remain on the bumps 22. Therefore, solderability can be improved.

  Moreover, in this manufacturing method, by using the protective tape 10 having good heat resistance as described above, the resin of the second thermoplastic resin layer 13 is based on the thermosetting of the adhesive layer 11 in the curing step (C). It can suppress that it protrudes from the material film 14 layer and adheres to the wafer 22. Therefore, after the adhesive layer 11 is cured, the layers constituting the protective tape 10 other than the adhesive layer 11 (the first thermoplastic resin layer 12, the second thermoplastic resin layer 13 and the base film layer 14). Can be easily peeled off. Thus, since the peelability of the protective tape 10 can be made favorable, a protective tape peeling process (E) can be performed after a hardening process (C). By performing the protective tape peeling step (E) after the curing step (C) as in the present manufacturing method, for example, compared to the case of performing the curing step (C) after the protective tape peeling step (E), The handling property when it is thin can be improved.

  Further, in this manufacturing method, since the adhesive layer 11 on the wafer surface on which the bumps are formed is cured and the bumps are reinforced before the dicing process step (F), the bumps are formed in the subsequent steps such as dicing, pick-up, and mounting. Can be reduced. In addition, a semiconductor device having excellent connection reliability can be obtained with a high yield.

  A semiconductor device obtained by this manufacturing method includes a semiconductor chip having a bump and an adhesive layer formed on the bump forming surface, and a circuit board having an electrode facing the bump, and is bonded to the bump forming surface of the semiconductor chip. Since the agent layer is formed, excellent connection reliability can be obtained.

  Hereinafter, examples of the present technology will be described. In this example, a protective tape was prepared by laminating an adhesive layer, a first thermoplastic resin layer, a second thermoplastic resin layer, and a base film layer. Using protective tape, protective tape application process (A), grinding process (B), curing process (C), adhesive tape application process (D), protective tape peeling process (E), and dicing process (F), the expanding process (G), the pick-up process (H), and the mounting process (I) were sequentially performed to manufacture a semiconductor device. And heat resistance, solder joint property, and bump embedding property were evaluated.

[Storage shear modulus]
The storage shear modulus at 60 ° C. of the adhesive layer and the thermoplastic resin layer was calculated using a viscoelasticity measuring device. The measurement conditions were set to a measurement temperature range of 0 to 120 ° C., a temperature increase rate of 5 ° C./min, a frequency of 1 Hz, and a strain of 0.1%.

[Preparation of protective tape]
<Preparation of thermoplastic resin layer (film 1)>
A second thermoplastic resin layer (any one of the following resin layers B1 to B5) is applied on a PET substrate, cured with ultraviolet rays, and then extruded and melt-molded in advance to form a first thermoplastic resin layer (the following resin layer A1). ) Was laminated.

<First thermoplastic resin layer>
Resin layer A1: Ethylene / vinyl acetate copolymer (VF120T, manufactured by Ube Maruzen Polyethylene Co., Ltd.), storage shear modulus at 60 ° C .: 3.1E + 06 Pa

<Second thermoplastic resin layer>
Resin layers B1 to B5 were prepared using the monomers shown in Table 1.

[Resin layer B1]
The resin layer B1 is composed of 96 parts by mass of 2EHA (acrylic acid-2-ethylhexyl), 3.5 parts by mass of acrylic acid, and 0.5 parts by mass of KAYARAD FM-400 (manufactured by Nippon Kayaku Co., Ltd.). The amount of crosslinking group is 0.28%.

[Resin layer B2]
The resin layer B2 is composed of 96.49 parts by mass of 2EHA, 3.5 parts by mass of acrylic acid, and 0.01 parts by mass of KAYARAD FM-400, and has a crosslinking group amount of 0.01%.

[Resin layer B3]
The resin layer B3 is composed of 91.5 parts by mass of 2EHA, 3.5 parts by mass of acrylic acid, and 5 parts by mass of KAYARAD FM-400, and has a crosslinking group amount of 2.85%.

[Resin layer B4]
The resin layer B4 is composed of 96.5 parts by mass of 2EHA and 3.5 parts by mass of acrylic acid, and has a crosslinking group amount of 0%.

[Resin layer B5]
The resin layer B5 is composed of 86.5 parts by mass of 2EHA, 3.5 parts by mass of acrylic acid, and 10 parts by mass of KAYARAD FM-400, and has a crosslinking group amount of 5.82%.

<Preparation of adhesive layer (film 2)>
[Adhesive Layer No. 1]
13.0 parts by mass of a film-forming resin (phenoxy resin (PKHH, manufactured by Union Carbide Corp.)) and 54.8 of epoxy resin (dicyclopentadiene type epoxy resin (HP7200H, manufactured by DIC Corp.)) 32.4 parts by mass and 32.4 parts by mass of a curing agent (novolak type phenolic resin (TD-2093, manufactured by DIC Corporation)) and 0 curing aid (2-ethyl-4-methylimidazole (2E4MZ)) An adhesive composition was prepared by blending 3 parts by mass. The prepared adhesive composition was applied to peeled PET (Polyethylene terephthalate) using a bar coater so that the thickness after drying was 30 μm, and dried in an oven. 1 was produced. Adhesive layer No. The storage shear modulus of 1 at 60 ° C. was 3.3E + 03 Pa.

[Adhesive Layer No. 2]
Except that 25.0 parts by mass of silica filler (Aerosil RY200, manufactured by Nippon Aerosil Co., Ltd.) was further blended to prepare an adhesive composition, the adhesive layer No. In the same manner as the production method of No. 1, the adhesive layer No. 2 was produced. Adhesive layer No. The storage shear modulus of 2 at 60 ° C. was 3.6E + 04 Pa.

<Example 1>
A thermoplastic resin layer (film 1) and an adhesive layer (film 2) were laminated to produce a protective tape. As the film 1, a film composed of a PET base material (75 μm), a thermoplastic resin layer A1 (50 μm), and a thermoplastic resin layer B1 (450 μm) was used. As the film 2, adhesive layer No. 1 (20 μm) was used.

<Example 2>
A protective tape of Example 2 was produced in the same manner as in Example 1 except that the thermoplastic resin layer B1 in the film 1 was changed to the thermoplastic resin layer B2 having the same thickness.

<Example 3>
A protective tape of Example 3 was produced in the same manner as in Example 1 except that the thermoplastic resin layer B1 in the film 1 was changed to a thermoplastic resin layer B3 having the same thickness.

<Comparative Example 1>
A protective tape of Comparative Example 1 was produced in the same manner as in Example 1 except that the thermoplastic resin layer B1 in the film 1 was changed to a thermoplastic resin layer B4 having the same thickness.

<Comparative example 2>
A protective tape of Comparative Example 2 was produced in the same manner as in Example 1 except that the thermoplastic resin layer B1 in the film 1 was changed to a thermoplastic resin layer B5 having the same thickness.

<Comparative Example 3>
Adhesive layer No. 1 and adhesive layer No. 1 of the same thickness. A protective tape of Comparative Example 3 was produced in the same manner as in Example 1 except that it was changed to 2.

[Fabrication of semiconductor devices]
The adhesive layer surface of the protective tape is attached to a wafer (size: 5 cm × 5 cm × 700 μmt) on which solder bumps (φ = 250 μm, H = 200 μm, pitch = 250 μm) are formed, and a vacuum laminator (product name: VTM-) 300, manufactured by Takatori Co., Ltd.).

  Next, a back grind process was performed to a thickness of the wafer to 300 μm with a grinder (product name: DFG8560, manufactured by Disco Corporation). After the adhesive layer of the protective tape on the wafer was cured in an oven at 130 ° C. for 2 hours, the protective tape was peeled off leaving the adhesive layer, and the other layers (PET substrate, first thermoplastic resin layer) , And the second thermoplastic resin layer). Then, the wafer was diced and separated into chips, and then mounted on a substrate (a gold electrode with flux) by a mounter, and the chip and the substrate were soldered in a reflow furnace at a maximum of 260 ° C.

[Evaluation of heat resistance]
<Amount of resin protruding>
After the protective tape was cut, it was laminated on the wafer in the same manner as in the production of the semiconductor device described above. After curing at 130 ° C. for 2 hours, the amount of protrusion of the resin from the PET substrate (extruding distance) was measured with a microscope (100 times). The results are shown in Table 3.

[Removal of film]
After curing of the adhesive layer in the production of the semiconductor device described above, an adhesive tape having a width of 40 mm is laminated on the surface of the base film layer of the protective tape, and the adhesive layer and the resin layer on the adhesive layer side are pulled at a rate of 100 mm / min. It was investigated whether it was possible to peel between (resin layer A1). The results are shown in Table 3.

<Bump embedding>
After laminating the protective tape on the wafer in the production of the semiconductor device described above, observation with a microscope (100 times) is performed, and the one having no gap between the bumps of the adhesive layer is evaluated as “◯”, and there is a gap Was evaluated as “Δ”. The results are shown in Table 3.

[Evaluation of solderability]
When the flux was applied onto the gold electrode of the substrate and soldered at a reflow temperature of 260 ° C. at maximum, the area of the bump size was defined as 100%, and the area where the solder spreaded was measured. When the area where the solder spreads was 40% or more with respect to the area of the bump size, the solderability was evaluated as good, and when it was less than 40%, the solderability was evaluated as not good. The results are shown in Table 3.

  As in Examples 1 to 3, the amount of the crosslinking group represented by the above-described formula (1) of the second thermoplastic resin layer is 0.01 to 3%, which satisfies the above-described formula (2). It was found that when the protective tape was used, the heat resistance and solder jointability were good. It was also found that the bump embedding property was also good.

  As in Comparative Example 1, when a protective tape having a crosslinking group amount of less than 0.01% represented by the above-described formula (1) of the second thermoplastic resin layer is used, the heat resistance is not good. I understood. This is probably because the resin of the second thermoplastic resin layer melted during thermosetting, and the resin protruded greatly from the base film layer and adhered to the wafer, so that the peelability of the film was not good.

  When the protective tape in which the amount of the crosslinking group represented by the above-described formula (1) of the second thermoplastic resin layer exceeds 3% is used as in Comparative Example 2, the embedding property of the bump may not be good. I understood. This is probably because the degree of cross-linking of the second thermoplastic resin layer was too large.

  When the protective tape which does not satisfy | fill the conditions of Formula (2) mentioned above like the comparative example 3, ie, Gn / Ga is 0.01 or more, it turned out that solderability is not favorable. This is because the deformation or flow of the adhesive layer is not good, and when the protective tape is applied to the wafer, the adhesion of the adhesive layer on the bumps of the wafer cannot be suppressed, and the adhesive layer tends to remain on the bumps. It is thought that it became.

  DESCRIPTION OF SYMBOLS 10 Protective tape, 11 Adhesive layer, 12 1st thermoplastic resin layer, 13 2nd thermoplastic resin layer, 14 Base film layer, 21 Wafer, 22 Bump, 30 Adhesive tape, 31 Adhesive layer, 32 groups Material film layer

Claims (9)

It has an adhesive layer, a first thermoplastic resin layer, a second thermoplastic resin layer, and a base film layer in this order,
The amount of the crosslinking group represented by the following formula (1) of the second thermoplastic resin layer is 0.01 to 3%,
A protective tape that satisfies the following formula (2).
(1) Amount of crosslinking group (%) = (pmr / pmw × (pmf−1)) / (Σ (mr / mw)) × 100
(2) Gn / Ga <0.01
(In the formula (1), pmr is the ratio of the polyfunctional monomer used in the second thermoplastic resin layer, pmw is the molecular weight of the polyfunctional monomer, pmf is the number of functional groups of the polyfunctional monomer, mr Is the ratio of each monomer used in the second thermoplastic resin layer, mw is the molecular weight of each monomer, and in formula (2), Gn is the temperature of the adhesive layer at the application temperature at which the protective tape is applied. Storage shear modulus, Ga is the storage shear modulus of the first thermoplastic resin layer at the application temperature.)   The protective tape according to claim 1, wherein the sticking temperature is 40 to 80 ° C. The storage shear modulus at 60 ° C. of the first thermoplastic resin layer is 1.0E + 06 Pa to 1.0E + 09 Pa,
The protective tape of Claim 1 or 2 whose storage shear elastic modulus in 60 degreeC of the said adhesive bond layer is 1.0E + 01Pa-5.0E + 04Pa.   The protective tape according to any one of claims 1 to 3, wherein a storage shear elastic modulus at 60 ° C of the second thermoplastic resin layer is 1.0E + 04Pa to 2.0E + 06Pa.   The protective tape according to any one of claims 1 to 4, wherein the second thermoplastic resin layer is obtained by curing a composition having a polyfunctional monomer content of 0.01 to 5 mass%. .   The said composition contains a monofunctional monomer and a bifunctional monomer, The protective tape of Claim 5 whose content of a bifunctional monomer is 0.01-5 mass%.   The protective tape according to claim 1, wherein the first thermoplastic resin layer has a thickness of 10 to 200 μm. The adhesive layer is affixed to the wafer surface on which the bumps are formed,
The protective tape according to any one of claims 1 to 7, wherein a thickness of the second thermoplastic resin layer is not less than a height of the bump. A process (A) of applying the protective tape according to any one of claims 1 to 8 on the wafer surface on which the bump is formed;
A step (B) of grinding the opposite surface of the wafer to which the protective tape is applied;
A step (C) of curing the adhesive layer;
A step (D) of applying an adhesive tape to the grinding surface;
Step (E) of leaving the adhesive layer and peeling off the protective tape and removing the other layers;
And a step (F) of obtaining a semiconductor chip by dicing the wafer on which the adhesive tape is affixed.

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