JP5785420B2 - Protective film forming sheet and semiconductor chip manufacturing method - Google Patents

Description

  The present invention relates to a protective film forming sheet that can form a protective film on the back surface of a semiconductor chip and can improve the manufacturing efficiency of the chip. In particular, the present invention relates to a protective film forming sheet used for manufacturing a semiconductor chip to be mounted by a so-called face down method. Moreover, this invention relates to the manufacturing method of the semiconductor chip using the sheet | seat for protective film formation.

  In recent years, semiconductor devices have been manufactured using a so-called face down method. In the face-down method, a semiconductor chip (hereinafter simply referred to as “chip”) having electrodes such as bumps on a circuit surface is used, and the electrodes are bonded to a substrate. For this reason, the surface (chip back surface) opposite to the circuit surface of the chip may be exposed.

  The exposed back surface of the chip may be protected by an organic film. Conventionally, a chip having a protective film made of an organic film is obtained by applying a liquid resin to the back surface of a wafer by spin coating, drying and curing, and cutting the protective film together with the wafer. However, since the thickness accuracy of the protective film formed in this way is not sufficient, the product yield may be lowered.

  In order to solve the above problem, a protective film forming sheet having a protective sheet forming layer comprising a release sheet and a heat or energy ray curable component and a binder polymer component formed on the release sheet is disclosed. (Patent Document 1).

  With the recent widespread use of IC cards, thinning of the semiconductor chip that is a constituent member thereof has been promoted. For this reason, it has been required to reduce the thickness of a conventional wafer having a thickness of about 350 μm to 50 to 100 μm or less. However, as the semiconductor wafer becomes thinner, the risk of breakage increases during processing and transportation.

  For this reason, as shown in FIGS. 8 to 10, when grinding the back surface of the wafer, only the back inner peripheral portion 16 is ground, and the annular convex portion 17 is left on the back outer peripheral portion, so that the wafer has rigidity. (Patent Documents 2 to 4). As shown in FIG. 8, the surface of the wafer 11 has a surplus portion 15 in which the circuit 13 is not formed within a range of several mm from the outer peripheral end, and the circuit 13 is formed in the wafer inner peripheral portion 14 excluding the surplus portion. ing. In the wafer having the annular convex portion, the rear inner peripheral portion 16 corresponding to the circuit forming portion (wafer inner peripheral portion 14) on the front surface is ground to a predetermined thickness, and corresponds to the surplus portion 15 where no circuit is formed. The back outer peripheral portion remains without being ground and becomes an annular convex portion 17. Since the annular protrusion 17 has a relatively high rigidity, the wafer 11 ground in the above-described form can be stably transported and stored, and damage during processing is reduced. 9 is a perspective view from the back side where the annular convex portion 17 is formed, and FIG. 10 is a cross-sectional view of FIG.

JP 2002-280329 A JP 2007-19379 A JP 2007-266352 A JP 2007-287796 A

  However, when the protective film forming sheet described in Patent Document 1 is applied to the semiconductor wafer described in Patent Documents 2 to 4, the annular convex portion formed on the outer periphery of the back surface of the wafer becomes an obstacle. In some cases, the protective film-forming sheet could not be attached to the back surface of the wafer.

  The present invention has been made in view of the above circumstances, the circuit is formed on the front surface, the back surface inner peripheral portion (region surrounded by the annular convex portion) of the semiconductor wafer having an annular convex portion on the back outer peripheral portion, It aims at providing the sheet | seat for protective film formation which can form a protective film. It is another object of the present invention to provide a method for manufacturing a semiconductor chip using the protective film forming sheet.

The present invention includes the following gist.
(1) A protective film-forming sheet having a protective film-forming layer formed so as to be peelable on a convex part of a laminated film having a circular convex part.

(2) The protective film-forming sheet according to (1), wherein the laminated film includes a base material and a thickness adjusting layer, and the thickness adjusting layer is a circular convex portion.

(3) For forming a protective film according to (1) or (2), which is used to form a protective film on the inner peripheral portion of the back surface of a semiconductor wafer having a circuit formed on the front surface and an annular convex portion on the outer peripheral portion of the back surface. Sheet.

(4) The thickness t1 of the protective film forming layer, the thickness t2 of the circular convex portion, and the step T3 between the inner peripheral portion of the back surface of the semiconductor wafer and the annular convex portion satisfy the relationship of t1 + t2 ≧ T3 (3) The sheet for forming a protective film according to the description.

(5) The inner peripheral portion of the back surface of the semiconductor wafer is circular, and the diameter D1 of the top surface of the circular convex portion and the diameter D2 of the inner peripheral portion of the back surface of the semiconductor wafer satisfy the relationship of D1 ≦ D2 (3 ) Or the protective film-forming sheet according to any one of (4).

(6) A back surface thickness adjusting layer is provided on the opposite surface of the circular convex portion in the laminated film, the back surface thickness adjusting layer thickness t3, the protective film forming layer thickness t1, and the circular convex portion thickness t2. And the sheet | seat for protective film formation in any one of (3)-(5) with which the level | step difference T3 of the back surface inner peripheral part of a semiconductor wafer and a cyclic | annular convex part satisfy | fills the relationship of t1 + t2 + t3> = T3.

(7) A process of applying the protective film-forming sheet according to any one of (1) to (6) to a rear inner peripheral portion of a semiconductor wafer having a circuit formed on the front surface and an annular convex portion on the rear outer peripheral portion. A method of manufacturing a semiconductor chip including:

  According to the present invention, a protective film can be formed on the inner peripheral portion of the back surface of the semiconductor wafer (the region surrounded by the annular convex portion) having a circuit formed on the front surface and an annular convex portion on the outer peripheral portion of the back surface.

It is a perspective view of the sheet | seat for protective film formation concerning this invention. It is sectional drawing of the sheet | seat for protective film formation concerning this invention. It is sectional drawing of the sheet | seat for protective film formation concerning this invention. It is sectional drawing of the sheet | seat for protective film formation concerning this invention. It is sectional drawing of the sheet | seat for protective film formation concerning this invention. It is sectional drawing of the sheet | seat for protective film formation concerning this invention. It is sectional drawing of the state which has stuck the protective film formation sheet which concerns on this invention to the semiconductor wafer. The top view of the circuit formation surface of a semiconductor wafer is shown. The perspective view of the semiconductor wafer in which the annular convex part was formed in the back peripheral part is shown. FIG. 10 shows a cross-sectional view of FIG. 9.

  Hereinafter, preferred embodiments of the present invention will be described more specifically with reference to the drawings, including the best mode.

  As shown in FIGS. 1 and 2, a protective film forming sheet 100 according to the present invention has a protective film forming layer 1 formed so as to be peelable on a convex portion of a laminated film 10 having a circular convex portion. . Hereinafter, the protective film forming layer 1 and the laminated film 10 will be described in detail.

(Protective film forming layer 1)
The protective film forming layer 1 contains a binder polymer component (A) and a curable component (B).

(A) Binder polymer component The binder polymer component (A) is used for imparting sufficient adhesion and film forming property (sheet processability) to the protective film forming layer. As the binder polymer component (A), conventionally known acrylic polymers, polyester resins, urethane resins, acrylic urethane resins, silicone resins, rubber-based polymers, and the like can be used.

  The weight average molecular weight (Mw) of the binder polymer component (A) is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. If the weight average molecular weight of the binder polymer component (A) is too low, the adhesive force between the protective film-forming layer and the release sheet increases, and transfer failure of the protective film-forming layer may occur. Adhesiveness may decrease and transfer to a chip or the like may not be possible, or the protective film may be peeled off from the chip or the like after transfer.

  An acrylic polymer is preferably used as the binder polymer component (A). The glass transition temperature (Tg) of the acrylic polymer is preferably -60 to 50 ° C, more preferably -50 to 40 ° C, and particularly preferably -40 to 30 ° C. If the glass transition temperature of the acrylic polymer is too low, the peel force between the protective film-forming layer and the release sheet may increase, resulting in poor transfer of the protective film-forming layer, and if it is too high, the adhesion of the protective film-forming layer will be reduced. However, the transfer to the chip or the like may be impossible, or the protective film may be peeled off from the chip or the like after the transfer.

  As a monomer which comprises the said acrylic polymer, a (meth) acrylic acid ester monomer or its derivative (s) is mentioned. For example, alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group, specifically methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl Examples include (meth) acrylate. In addition, (meth) acrylate having a cyclic skeleton, specifically cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, Examples include dicyclopentenyloxyethyl (meth) acrylate and imide (meth) acrylate. Furthermore, examples of the monomer having a functional group include hydroxymethyl (meth) acrylate having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like; in addition, glycidyl (meth) having an epoxy group. An acrylate etc. are mentioned. As the acrylic polymer, an acrylic polymer containing a monomer having a hydroxyl group is preferable because of its good compatibility with the curable component (B) described later. The acrylic polymer may be copolymerized with acrylic acid, methacrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, or the like.

  Furthermore, you may mix | blend the thermoplastic resin for maintaining the flexibility of the protective film after hardening as a binder polymer component (A). Such a thermoplastic resin preferably has a weight average molecular weight of 1,000 to 100,000, more preferably 3,000 to 10,000. The glass transition temperature of the thermoplastic resin is preferably -30 to 150 ° C, more preferably -20 to 120 ° C. Examples of the thermoplastic resin include polyester resin, urethane resin, phenoxy resin, polybutene, polybutadiene, and polystyrene. By containing the thermoplastic resin in the above range, the protective film forming layer follows the transfer surface of the protective film forming layer, and generation of voids and the like can be suppressed.

(B) Curable component The curable component (B) is a thermosetting component and / or an energy beam curable component.

  As the thermosetting component, a thermosetting resin and a thermosetting agent are used. As the thermosetting resin, for example, an epoxy resin is preferable.

  A conventionally well-known epoxy resin can be used as an epoxy resin. Specific examples of epoxy resins include polyfunctional epoxy resins, biphenyl compounds, bisphenol A diglycidyl ether and hydrogenated products thereof, orthocresol novolac epoxy resins, dicyclopentadiene type epoxy resins, biphenyl type epoxy resins, and bisphenols. Examples thereof include epoxy compounds having two or more functional groups in the molecule, such as A-type epoxy resin, bisphenol F-type epoxy resin, and phenylene skeleton-type epoxy resin. These can be used individually by 1 type or in combination of 2 or more types.

  In the protective film forming layer, the thermosetting resin is preferably 1 to 1500 parts by weight, more preferably 10 to 500 parts by weight, and particularly preferably 20 to 200 parts by weight with respect to 100 parts by weight of the binder polymer component (A). included. When the content of the thermosetting resin is less than 1 part by weight, sufficient adhesiveness may not be obtained. When the content exceeds 1500 parts by weight, the peeling force between the protective film forming layer and the release sheet increases, and the protective film is formed. Layer transfer failure may occur.

  The thermosetting agent functions as a curing agent for thermosetting resins, particularly epoxy resins. A preferable thermosetting agent includes a compound having two or more functional groups capable of reacting with an epoxy group in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride. Of these, phenolic hydroxyl groups, amino groups, acid anhydrides and the like are preferable, and phenolic hydroxyl groups and amino groups are more preferable.

  Specific examples of the phenolic curing agent include polyfunctional phenolic resin, biphenol, novolac type phenolic resin, dicyclopentadiene type phenolic resin, zylock type phenolic resin, and aralkylphenolic resin. A specific example of the amine curing agent is DICY (dicyandiamide). These can be used individually by 1 type or in mixture of 2 or more types.

  The content of the thermosetting agent is preferably 0.1 to 500 parts by weight and more preferably 1 to 200 parts by weight with respect to 100 parts by weight of the thermosetting resin. If the content of the thermosetting agent is small, the adhesiveness may not be obtained due to insufficient curing, and if it is excessive, the moisture absorption rate of the protective film forming layer may increase and the reliability of the semiconductor device may be reduced.

  As the energy ray curable component, a compound (energy ray polymerizable compound) containing an energy ray polymerizable group and polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams can be used. Specific examples of such energy ray-curable components include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or 1,4-butylene glycol. Examples include acrylate compounds such as diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer. Such a compound has at least one polymerizable double bond in the molecule, and usually has a weight average molecular weight of about 100 to 30,000, preferably about 300 to 10,000. The amount of the energy ray-curable component is preferably 1 to 1500 parts by weight, more preferably 10 to 500 parts by weight, and particularly preferably 20 to 200 parts by weight with respect to 100 parts by weight of the binder polymer component (A). .

  Further, as the energy ray curable component, an energy ray curable polymer in which an energy ray polymerizable group is bonded to the main chain or side chain of the binder polymer component (A) may be used. Such an energy ray curable polymer has a function as a binder polymer component (A) and a function as a curable component (B).

  The main skeleton of the energy ray curable polymer is not particularly limited, and may be an acrylic polymer widely used as the binder polymer component (A), and may be a polyester, a polyether, etc. In view of easy control of physical properties, it is particularly preferable to use an acrylic polymer as the main skeleton.

  The energy beam polymerizable group bonded to the main chain or side chain of the energy beam curable polymer is, for example, a group containing an energy beam polymerizable carbon-carbon double bond, specifically a (meth) acryloyl group or the like. Can be illustrated. The energy beam polymerizable group may be bonded to the energy beam curable polymer via an alkylene group, an alkyleneoxy group, or a polyalkyleneoxy group.

  The weight average molecular weight (Mw) of the energy beam curable polymer to which the energy beam polymerizable group is bonded is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. The glass transition temperature (Tg) of the energy ray curable polymer is preferably in the range of −60 to 50 ° C., more preferably −50 to 40 ° C., and particularly preferably −40 to 30 ° C.

  The energy ray curable polymer is, for example, an acrylic polymer containing a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group, and a substituent that reacts with the functional group and energy ray polymerization. It is obtained by reacting a polymerizable group-containing compound having 1 to 5 reactive carbon-carbon double bonds per molecule. Examples of the substituent that reacts with the functional group include an isocyanate group, a glycidyl group, and a carboxyl group.

  Examples of the polymerizable group-containing compound include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, (meth) acrylic acid, and the like. Is mentioned.

  Acrylic polymer is a (meth) acrylic monomer having functional groups such as hydroxyl group, carboxyl group, amino group, substituted amino group, and epoxy group, or a derivative thereof, and other (meth) acrylic acid ester monomers copolymerizable therewith. Or it is preferable that it is a copolymer which consists of its derivative (s).

  Examples of the (meth) acrylic monomer having a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, or an epoxy group or a derivative thereof include 2-hydroxyethyl (meth) acrylate having a hydroxyl group, 2-hydroxy Examples thereof include propyl (meth) acrylate; acrylic acid having a carboxyl group, methacrylic acid, itaconic acid; glycidyl methacrylate having an epoxy group, glycidyl acrylate, and the like.

  Examples of other (meth) acrylic acid ester monomers or derivatives thereof copolymerizable with the above monomers include alkyl (meth) acrylates having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl ( (Meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like; (meth) acrylate having a cyclic skeleton such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, Examples include isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, and imide acrylate. The acrylic polymer may be copolymerized with vinyl acetate, acrylonitrile, styrene or the like.

  Even in the case of using an energy ray curable polymer, the aforementioned energy ray polymerizable compound may be used in combination, or the binder polymer component (A) may be used in combination.

  By imparting energy beam curability to the protective film forming layer, the protective film forming layer can be cured easily and in a short time, and the production efficiency of the chip with protective film is improved. Conventionally, a protective film for a chip is generally formed of a thermosetting resin such as an epoxy resin, but the curing temperature of the thermosetting resin exceeds 200 ° C., and the curing time requires about 2 hours. It was an obstacle to improving production efficiency. However, since the energy ray-curable protective film forming layer is cured in a short time by energy ray irradiation, a protective film can be easily formed, which can contribute to improvement in production efficiency.

The other component protective film forming layer may contain the following components in addition to the binder polymer component (A) and the curable component (B).

(C) A coloring agent (C) can be mix | blended with a coloring agent protective film formation layer. By blending the colorant, malfunction of the semiconductor device due to infrared rays or the like generated from surrounding devices when the semiconductor device is incorporated into equipment can be prevented. As the colorant, organic or inorganic pigments and dyes are used. Among these, black pigments are preferable from the viewpoint of electromagnetic wave and infrared shielding properties. As the black pigment, carbon black, aniline black, activated carbon and the like are used, but are not limited thereto. Carbon black is particularly preferable from the viewpoint of increasing the reliability of the semiconductor device. When an ultraviolet ray curable component is added as an energy ray curable component, the transparency of the ultraviolet ray may be reduced by the addition of the colorant (C). You may mix | blend a chain transfer agent.

  The blending amount of the colorant (C) is preferably 0.1 to 35 parts by weight, more preferably 0.5 to 25 parts by weight, particularly preferably 100 parts by weight of the total solid content constituting the protective film forming layer. Is 1 to 15 parts by weight.

(D) Curing accelerator The curing accelerator (D) is used to adjust the curing rate of the protective film forming layer. The curing accelerator (D) is preferably used particularly when the epoxy resin and the thermosetting agent are used in combination in the curable component (B).

  Preferred curing accelerators include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-phenylimidazole, 2-phenyl- Imidazoles such as 4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole; Organic phosphines such as tributylphosphine, diphenylphosphine, triphenylphosphine; And tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. These can be used individually by 1 type or in mixture of 2 or more types.

  The curing accelerator (D) is preferably contained in an amount of 0.01 to 10 parts by weight, more preferably 0.1 to 1 part by weight, with respect to 100 parts by weight of the curable component (B). By containing the curing accelerator (D) in an amount within the above range, it has excellent adhesive properties even when exposed to high temperatures and high humidity, and has high reliability even when exposed to severe reflow conditions. Can be achieved. If the content of the curing accelerator (D) is low, sufficient adhesion characteristics cannot be obtained due to insufficient curing, and if it is excessive, the curing accelerator having a high polarity will adhere to the protective film forming layer under high temperature and high humidity. The reliability of the semiconductor device is lowered by moving to the side and segregating.

(E) Coupling agent The coupling agent (E) may be used to improve the adhesion, adhesion and / or cohesion of the protective film to the chip of the protective film forming layer. Moreover, the water resistance can be improved by using a coupling agent (E), without impairing the heat resistance of the protective film obtained by hardening | curing a protective film formation layer.

  As the coupling agent (E), a compound having a group that reacts with a functional group of the binder polymer component (A), the curable component (B), or the like is preferably used. As the coupling agent (E), a silane coupling agent is desirable. Such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacryloxypropyl). ) Trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N- Phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltrimethoxy Silane, meth Examples include rutriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These can be used individually by 1 type or in mixture of 2 or more types.

  The coupling agent (E) is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the total of the binder polymer component (A) and the curable component (B). Preferably it is contained in a proportion of 0.3 to 5 parts by weight. If the content of the coupling agent (E) is less than 0.1 parts by weight, the above effect may not be obtained, and if it exceeds 20 parts by weight, it may cause outgassing.

(F) Inorganic filler By blending the inorganic filler (F) in the protective film forming layer, it is possible to adjust the thermal expansion coefficient in the protective film after curing, and the protective film after curing with respect to the semiconductor chip The reliability of the semiconductor device can be improved by optimizing the thermal expansion coefficient. Moreover, it becomes possible to reduce the moisture absorption rate of the protective film after hardening.

  Preferable inorganic fillers include powders such as silica, alumina, talc, calcium carbonate, titanium oxide, iron oxide, silicon carbide, boron nitride, beads formed by spheroidizing them, single crystal fibers, and glass fibers. Among these, silica filler and alumina filler are preferable. The said inorganic filler (F) can be used individually or in mixture of 2 or more types. Content of an inorganic filler (F) can be normally adjusted in 1-80 weight part with respect to 100 weight part of total solids which comprise a protective film formation layer.

(G) When the photopolymerization initiator protective film forming layer contains an energy ray curable component as the curable component (B) described above, an energy ray such as an ultraviolet ray is irradiated on the use of the energy ray curable component. Curing the curable component. In this case, the polymerization curing time and the amount of light irradiation can be reduced by including the photopolymerization initiator (G) in the composition.

  Specific examples of such photopolymerization initiator (G) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal. 2,4-diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2-hydroxy- 2-methyl-1- [4- (1-methylvinyl) phenyl] propanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and β-alkyl Examples thereof include roll anthraquinone. A photoinitiator (G) can be used individually by 1 type or in combination of 2 or more types.

  It is preferable that 0.1-10 weight part is contained with respect to 100 weight part of energy-beam curable components, and, as for the mixture ratio of a photoinitiator (G), it is more preferable that 1-5 weight part is contained. If it is less than 0.1 part by weight, satisfactory transferability may not be obtained due to insufficient photopolymerization. If it exceeds 10 parts by weight, a residue that does not contribute to photopolymerization is generated, and the curability of the protective film forming layer May be insufficient.

(H) In order to adjust the initial adhesive force and cohesive force of the crosslinker protective film forming layer, a crosslinker may be added. Examples of the crosslinking agent (H) include organic polyvalent isocyanate compounds and organic polyvalent imine compounds.

  Examples of the organic polyvalent isocyanate compound include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these organic polyvalent isocyanate compounds, and these organic polyvalent isocyanate compounds. And a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound with a polyol compound.

  Examples of organic polyvalent isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane. -2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, trimethylolpropane adduct tolylene diisocyanate and lysine Isocyanates.

  Examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri -Β-aziridinylpropionate and N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine can be exemplified.

  The crosslinking agent (H) is usually 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 100 parts by weight of the total amount of the binder polymer component (A) and the energy ray curable polymer. It is used at a ratio of 0.5 to 5 parts by weight.

(I) In addition to the above, various additives may be blended in the general-purpose additive protective film forming layer as necessary. Examples of various additives include leveling agents, plasticizers, antistatic agents, and antioxidants.

  The protective film forming layer composed of each component as described above has adhesiveness and curability, and in an uncured state, is easily adhered by pressing against a semiconductor wafer, a chip or the like. Then, after curing, a protective film having high impact resistance can be provided, the adhesive strength is excellent, and a sufficient protective function can be maintained even under severe high temperature and high humidity conditions. The protective film forming layer may have a single layer structure, or may have a multilayer structure as long as one or more layers containing the above components are included.

(Laminated film 10)
As shown in FIG. 2, the laminated film 10 includes a base material 2 and a thickness adjustment layer 3, and the thickness adjustment layer 3 is preferably a circular convex portion.

  Examples of the substrate 2 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, etc. The transparent film is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. Further, in addition to the transparent film, an opaque film, a fluororesin film, or the like colored with these can be used.

  The thickness of the base material 2 is not specifically limited, Preferably it is 10-500 micrometers, More preferably, it is 15-300 micrometers, Most preferably, it is 20-250 micrometers.

  In addition, as shown in FIG. 3, the pressure-sensitive adhesive layer 4 can be formed on one side of the substrate 2. The substrate 2 is laminated with the thickness adjusting layer 3 via the pressure-sensitive adhesive layer 4.

  The pressure-sensitive adhesive layer 4 can be formed of various conventionally known pressure-sensitive adhesives. Such an adhesive is not limited at all, but an adhesive such as rubber-based, acrylic-based, silicone-based, or polyvinyl ether is used. In addition, an energy ray curable adhesive, a heat-foaming adhesive, or a water swelling adhesive can be used.

  The thickness of the pressure-sensitive adhesive layer 4 is preferably 2 to 20 μm, more preferably 3 to 15 μm. When the thickness of the pressure-sensitive adhesive layer 4 is less than 2 μm, sufficient adhesive strength for holding the thickness adjusting layer 3 may not be exhibited. On the other hand, if the thickness of the pressure-sensitive adhesive layer 4 exceeds 20 μm, the applied pressure may be absorbed when the protective film forming layer is applied, and the adhesiveness may deteriorate.

  The thickness adjusting layer 3 is formed of a single layer resin film or a laminated resin film. The film illustrated as the above-mentioned base material 2 can be used for the resin film. The number of laminated resin films is not particularly limited. In addition, the material of the resin film to laminate | stack may be the same, and may differ.

  Moreover, you may form the thickness adjustment layer 3 with the adhesive film which formed the adhesive layer 6 in the single side | surface of the resin film 5, as shown in FIG.4 and FIG.5. In FIG. 4, the laminated film 10 has a configuration in which the pressure-sensitive adhesive layer 4 is formed on one side of the substrate 2, and the substrate 2 and the resin film 5 of the thickness adjusting layer 3 are laminated via the pressure-sensitive adhesive layer 4. It has become. In FIG. 5, the laminated film 10 has a configuration in which the base material 2 and the pressure-sensitive adhesive layer 6 of the thickness adjusting layer 3 are laminated. The pressure-sensitive adhesive layer 6 can be formed using the pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer 4 described above.

  Moreover, you may form the thickness adjustment layer 3 by laminating | stacking two or more of the said adhesive films. The number of laminated adhesive films is not particularly limited. In addition, the material of the resin film which comprises the adhesive film to laminate | stack, and the adhesive layer may be the same, and may differ.

  Further, as shown in FIG. 6, the thickness adjusting layer 3 may be formed of a double-sided pressure-sensitive adhesive film in which pressure-sensitive adhesive layers 6 and 6 ′ are formed on both surfaces of the resin film 5. In FIG. 6, the laminated film 10 has a configuration in which the base material 2 and the adhesive layer 6 ′ of the thickness adjusting layer 3 are laminated. The pressure-sensitive adhesive layer 6 ′ can be formed using the pressure-sensitive adhesive that forms the above-described pressure-sensitive adhesive layer 4.

(Protective film forming sheet)
The protective film-forming sheet is obtained by mixing the above-mentioned components constituting the protective film-forming layer at an appropriate ratio in an appropriate solvent and forming the protective film-forming layer composition in the above-described circular convex shape of the laminated film 10. It is obtained by coating and drying on the part. Alternatively, the protective film-forming layer composition may be applied to a process film different from the laminated film 10 and dried to form a film, which may be transferred onto the circular convex portion of the laminated film 10.

  In the protective film forming sheet of the present invention, the laminated film 10 is peeled off when used, and the protective film forming layer 1 is transferred to a semiconductor wafer. In particular, when the laminated film 10 is peeled after the protective film forming layer 1 is cured with energy rays, the laminated film 10 needs to have energy ray permeability. Therefore, when ultraviolet rays are used as the energy rays, the laminated film 10 is configured using an ultraviolet transmissive substrate or a resin film.

  In order to facilitate peeling between the protective film forming layer 1 and the laminated film 10, when the surface of the laminated film 10 on which the protective film forming layer 1 is formed is a resin film (see, for example, FIG. 5) The surface tension is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. The lower limit is usually about 25 mN / m. Such a resin film having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the resin film and performing a release treatment.

  As the release agent used for the release treatment, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, and the like are used. In particular, alkyd, silicone, and fluorine release agents are heat resistant. This is preferable.

  In order to release the surface of the resin film using the release agent described above, the release agent can be applied as it is without solvent, or diluted or emulsified with a solvent, using a gravure coater, Mayer bar coater, air knife coater, roll coater, etc. Then, the laminate may be formed by room temperature or heating or electron beam curing, wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, or the like.

  In addition, in order to facilitate peeling between the protective film forming layer 1 and the laminated film 10, the surface of the laminated film 10 on which the protective film forming layer 1 is formed is an adhesive layer (see, for example, FIGS. 4 and 6). ), The pressure-sensitive adhesive layer is preferably formed of a pressure-sensitive adhesive having such a weak adhesive strength that the protective film forming layer can be peeled off. In addition, the pressure-sensitive adhesive layer may be formed of a pressure-sensitive adhesive whose adhesive force is reduced to such an extent that the protective film forming layer can be peeled off by energy ray irradiation. However, when the protective film forming layer is formed on the pressure-sensitive adhesive layer, there is a process in which heat is applied, or if the protective film-forming layer and the pressure-sensitive adhesive layer are in close contact with each other over a long period of time, the protective film-forming layer and the pressure-sensitive adhesive There is a possibility that the layer may stick and be unable to be peeled off.

  As shown in FIG. 2, in the protective film forming sheet 100 according to the present invention, the thickness t1 of the protective film forming layer 1 is preferably 3 to 500 μm, more preferably 5 to 300 μm. Further, the thickness t2 of the circular convex portion (thickness adjusting layer 3) is preferably 10 to 1000 μm, more preferably 20 to 700 μm. The protective film forming sheet 100 according to the present invention is preferably used for forming a protective film on the inner peripheral portion of the back surface of a semiconductor wafer having a circuit formed on the front surface and an annular convex portion on the outer peripheral portion of the back surface. FIG. 9 shows a semiconductor in which the outermost periphery of the semiconductor wafer 11 and the outer periphery of the annular protrusion 17 are the same, and the annular protrusion is provided so that the outer periphery of the annular protrusion 17 and the inner periphery of the annular protrusion are concentric. Although a perspective view of the wafer is shown, the outer periphery of the annular convex portion (the outermost periphery of the wafer 11) may not be circular because a notch is provided. On the other hand, the shape of the inner periphery of the annular protrusion and the inner periphery of the back surface defined thereby is preferably circular so that the circular protrusion of the protective film forming sheet 100 of the present invention can be easily applied. . The t1 and t2 are preferably designed in relation to the step T3 between the back inner peripheral portion 16 and the annular convex portion 17 of the semiconductor wafer shown in FIG. Hereinafter, the semiconductor wafer 11 will be described.

  The semiconductor wafer 11 may be a silicon wafer or a compound semiconductor wafer such as gallium / arsenic. The formation of the circuit 13 on the wafer surface can be performed by various methods including conventionally used methods such as an etching method and a lift-off method. In the circuit forming process of the semiconductor wafer, a predetermined circuit 13 is formed. The circuit 13 is formed in a lattice shape on the surface of the inner peripheral portion 14 of the wafer 11, and a surplus portion 15 in which no circuit is present remains in a range of several mm from the outer peripheral end. The thickness of the wafer 11 before grinding is not particularly limited, but is usually about 500 to 1000 μm.

  At the time of back grinding, an adhesive sheet called a surface protective sheet is attached to the circuit surface in order to protect the circuit 13 on the surface. In the back surface grinding, the circuit surface side (that is, the surface protection sheet side) of the wafer 11 is fixed by a chuck table or the like, and the back surface side where the circuit 13 is not formed is ground by a grinder. At the time of back surface grinding, first, the entire back surface is ground to a predetermined thickness, and then only the back surface inner peripheral portion 16 corresponding to the circuit forming portion (inner peripheral portion 14) on the front surface is ground, and the surplus portion 15 where the circuit 13 is not formed. The back surface area corresponding to is left without being ground. As a result, in the semiconductor wafer 11 after grinding, only the inner peripheral portion 16 on the back surface is further thinly ground, and the annular convex portion 17 remains on the outer peripheral portion. Such back surface grinding can be performed, for example, by a known method described in Patent Documents 2 to 4 described above.

  The total thickness T1 (see FIG. 10) of the annular convex portion 17 is not particularly limited, as long as it provides the necessary rigidity to the wafer and does not impair handling properties, and is generally about 400 to 725 μm. . The width of the annular convex portion is about the width of the surplus portion 15, and is generally about 2 to 5 mm. The thickness T2 of the inner peripheral portion 16 depends on the device design, and is usually about 25 to 200 μm. Therefore, the step T3 (= T1-T2) between the back inner peripheral portion 16 and the annular convex portion 17 is about 200 to 700 μm.

  After the back grinding process, a process of removing the crushed layer generated by grinding may be performed. Further, following the back surface grinding step, if necessary, the back surface may be subjected to processing involving heat generation such as etching processing, metal film deposition on the back surface, or processing performed at a high temperature such as organic film baking. . According to the wafer 11 in which only the back inner peripheral portion 16 is ground to a predetermined thickness and the outer peripheral portion has the annular convex portion 17, the annular convex portion 17 has high rigidity. Storage, processing, etc. can be performed.

  After the back surface grinding step, the protective film forming sheet 100 according to the present invention shown in FIGS. 1 to 6 is pasted on the region surrounded by the annular convex portion 17 on the ground surface side of the wafer 11. In order to improve the sticking property, the thickness t1 of the protective film forming layer in the protective film forming sheet 100, the thickness t2 of the circular convex portion, and the back inner peripheral portion 16 and the annular convex portion 17 in the semiconductor wafer described above. It is preferable that the step T3 (= T1−T2) satisfies the relationship of t1 + t2 ≧ T3. Moreover, it is preferable that t1, t2, and T3 satisfy the relationship of t1 + t2 ≦ T3 + 200 μm. When the difference between T3 and t1 + t2 is too large, a step is generated between the circular convex portion and the annular convex portion of the semiconductor wafer when the protective film forming sheet is stuck on the semiconductor wafer by pressing the top and bottom with a nip roll. When the nip roll goes over the step, the semiconductor wafer may be damaged. Moreover, in order to improve sticking property, the diameter D1 of the top surface 7 in the circular convex part shown in FIG. 1 and the diameter D2 of the back surface inner peripheral part 16 of the semiconductor wafer satisfy the relationship of D1 ≦ D2. preferable.

  Moreover, in order to make the protective film formation layer 1 and the back surface inner peripheral part 16 of a semiconductor wafer contact, back surface thickness is formed in the surface opposite to the thickness adjustment layer formation surface in a base material (opposite surface of the circular convex part in a laminated film). An adjustment layer may be provided. It is preferable that the thickness t3 of the back surface thickness adjusting layer and the above t1, t2, and T3 satisfy the relationship of t1 + t2 + t3 ≧ T3. FIG. 7 shows a state in which the protective film forming sheet 100 provided with the back surface thickness adjusting layer 7 is stuck to the semiconductor wafer 11 by being pressed by the nip rolls 21 existing above and below. When t1, t2, and T3 satisfy t1 + t2 <T3, if the back surface thickness adjusting layer is not provided, when the protective film forming sheet is attached to the semiconductor wafer, the inside of the back surface of the protective film forming layer and the semiconductor wafer There is a possibility that the peripheral portion 16 is not in contact with the protective film forming layer and the inner peripheral portion of the back surface of the semiconductor wafer is not bonded. However, when the back surface thickness adjusting layer is present, even if t1 + t2 <T3 is satisfied, the thickness of the protective film forming sheet-side nip roll 21 pressing the back surface thickness adjusting layer 7 as shown in FIG. The adjustment layer 3 is pressed toward the back inner peripheral part 16 side of the wafer, the protective film forming layer 1 and the back inner peripheral part 16 come into contact, and the protective film forming layer 1 can be bonded to the rear inner peripheral part 16. The region where the back surface thickness adjusting layer is provided on the substrate is the same as the region where the thickness adjusting layer is formed or larger than the region where the thickness adjusting layer is formed (the back surface thickness adjusting layer is provided on the base material). It is preferable that a region where the thickness adjusting layer is formed fits in a region to be formed).

  The back surface thickness adjusting layer can have the same material and configuration as the above-described thickness adjusting layer.

  In addition, by interposing a process film capable of pressing the thickness adjusting layer against the back inner peripheral portion 16 side of the wafer between the protective film forming sheet and the nip roll on the protective film forming sheet side, t1, t2, And T3 can adhere the protective film forming layer of the protective film forming sheet satisfying t1 + t2 <T3 to the back inner peripheral portion 16 of the semiconductor wafer.

  In addition, in order to protect a protective film formation layer, you may laminate | stack the light peelable peeling film on the upper surface of a protective film formation layer before use of the sheet | seat for protective film formation.

(Semiconductor chip manufacturing method)
In the method for manufacturing a semiconductor chip according to the present invention, a circuit is formed on the front surface, the protective film forming sheet is pasted on the inner peripheral portion of the rear surface of the semiconductor wafer having an annular convex portion on the outer peripheral surface, and the protective film is formed on the rear surface. A semiconductor chip having the following characteristics is obtained. The method for attaching the protective film-forming sheet is not particularly limited. In addition, the semiconductor chip manufacturing method according to the present invention preferably further includes the following steps (1) to (3), and the steps (1) to (3) are performed in an arbitrary order.
Step (1): peeling off the protective film forming layer and the laminated film,
Step (2): curing the protective film forming layer,
Step (3): Dicing the semiconductor wafer and the protective film forming layer.

  Details of the process in which the steps (1) to (3) are performed in an arbitrary order are described in detail in JP-A-2002-280329. As an example, the case where it performs in order of process (1), (2), (3) is demonstrated.

  First, the protective film formation layer formed on the laminated film of the said protective film formation sheet is affixed to the back surface inner peripheral part of the semiconductor wafer which has a circuit formed in the surface and has a cyclic | annular convex part in a back surface outer peripheral part. As described above, when t1, t2, t3, and T3 satisfy t1 + t2 ≧ T3 or t1 + t2 + t3 ≧ T3 and the relationship of D1 ≦ D2 is established, it is easy to bond the protective film forming layer to the inner periphery of the back surface of the semiconductor wafer. It is. Next, the laminated film is peeled from the protective film forming layer to obtain a laminated body of the semiconductor wafer and the protective film forming layer. Next, the protective film forming layer is cured, and a protective film is formed on the entire inner surface of the back surface of the wafer. Since the protective film forming layer contains the curable component (B), the protective film forming layer is cured by heat or energy ray irradiation. As a result, a protective film made of a cured resin is formed on the inner peripheral portion of the back surface of the wafer, and the strength is further improved as compared with the case of the wafer alone, so that it is possible to reduce the damage to the thin wafer during handling. In addition, the thickness of the protective film is excellent compared to a coating method in which a coating liquid for the protective film is directly applied to the back surface of the wafer or chip. In particular, it is considerably difficult to provide a protective film by spin coating on the inner peripheral portion of the back surface of a semiconductor wafer having an annular convex portion on the outer peripheral portion on the back surface.

  Next, the laminated body of the semiconductor wafer and the protective film is diced for each circuit formed on the wafer surface. Dicing is performed so as to cut both the wafer and the protective film. The dicing of the wafer is performed by a conventional method using a dicing sheet (see, for example, JP 2010-140956 A). As a result, a semiconductor chip having a protective film on the back surface is obtained.

  Finally, the diced chip is picked up by a general-purpose means such as a collet to obtain a semiconductor chip having a protective film on the back surface. According to the present invention, a highly uniform protective film can be easily formed on the back surface of the chip, and cracks after the dicing process and packaging are less likely to occur. Then, the semiconductor device can be manufactured by mounting the semiconductor chip on a predetermined base by the face-down method. Further, a semiconductor device can be manufactured by adhering a semiconductor chip having a protective film on the back surface to another member (on the chip mounting portion) such as a die pad portion or another semiconductor chip.

  In addition, when using an energy-beam curable component as a sclerosing | hardenable component (B), although it depends also on the kind of this compound, polymerization failure may be caused in the environment where oxygen exists. In this case, it is preferable to perform energy ray curing of the protective film forming layer in an environment where the protective film forming layer is not directly exposed to oxygen, and particularly in the order of steps (2), (1), and (3). Is preferred. When the steps (1) to (3) are performed in this order, the polymerization failure due to oxygen does not occur because the protection film formation layer is covered with the laminated film when the protection film formation layer is cured with energy rays. At this time, when the diameter D1 of the top surface 7 in the circular convex portion shown in FIG. 1 and the diameter D2 of the back surface inner peripheral portion 16 of the semiconductor wafer satisfy the relationship D1 = D2, the outer periphery of the circular convex portion Since there is no space between the inner periphery of the annular convex portions provided on the back surface of the semiconductor wafer, oxygen exposure near the end portion to the protective film forming layer can be prevented, which is preferable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the following examples and comparative examples, <paste evaluation> and <air mixing length evaluation> were performed as follows. Moreover, the silicon wafer which has the following shape, and the following composition for protective film formation layers were used.

<Attachment evaluation>
Using a laminator (Taisei Laminator Co., Ltd., First Laminator UA-400III, conditions: pressure 0.3 MPa, speed: 0.3 m / min, temperature 70 ° C.), protective film formation obtained in Examples or Comparative Examples The sheet for application was affixed to a semiconductor wafer having an annular projection on the outer periphery of the back surface. What was able to stick the protective film formation sheet to the back inner peripheral part of the semiconductor wafer was evaluated as “OK”.

<Evaluation of air mixing length>
Using a laminator (Taisei Laminator Co., Ltd., First Laminator UA-400III, conditions: pressure 0.3 MPa, speed: 0.3 m / min, temperature 70 ° C.), protective film formation obtained in Examples or Comparative Examples The sheet for application was affixed to a semiconductor wafer having an annular projection on the outer periphery of the back surface. Thereafter, the air mixing length (the length of the part not attached) was measured visually from the outer periphery of the protective film forming layer.

<Wafer shape>
Outer diameter: 200mm
Inner diameter of annular convex portion (diameter (D2) of inner peripheral portion of back surface): 195 mm
Inner peripheral thickness (T2): 100 μm
Annular convex thickness (T1): 350 μm
Step between the inner peripheral portion and the annular convex portion (T3 = T1-T2): 250 μm

<Composition for protective film forming layer>
Each component which comprises a protective film formation layer is shown below. In addition, Table 1 shows the amount of each component.
(A) Binder polymer component: acrylic polymer comprising 55 parts by weight of n-butyl acrylate, 15 parts by weight of methyl methacrylate, 20 parts by weight of glycidyl methacrylate, and 15 parts by weight of 2-hydroxyethyl acrylate (weight average molecular weight: 900,000, glass transition (Temperature: -28 ° C)
(B) Curing component (B1) Bisphenol A type epoxy resin (epoxy equivalent 180 to 200 g / eq)
(B2) Dicyclopentadiene type epoxy resin (Dainippon Ink & Chemicals, Epiklon HP-7200HH)
(B3) Dicyandiamide (Asahi Denka, Adeka Hardener 3636AS)
(C) Colorant: Black pigment (carbon black, manufactured by Mitsubishi Chemical Corporation, # MA650, average particle size 28 nm)
(D) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Chemicals Co., Ltd., Curazole 2PHZ)
(E) Coupling agent: A-1110 (Nippon Unicar)
(F) Inorganic filler: Silica filler (fused quartz filler, average particle size 8 μm)

Example 1
3 parts by weight of aromatic polyisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) and toluene with respect to 100 parts by weight of an acrylic copolymer based on butyl acrylate (SK Dyne 1811L, manufactured by Soken Chemical Co., Ltd.) 50 parts by weight were mixed to obtain an adhesive composition.

  Using a release material (SP-PET3811 manufactured by Lintec Corporation, thickness 38 μm, surface tension less than 30 mN / m, melting point 200 ° C. or higher), the thickness after drying the pressure-sensitive adhesive composition on the release-treated surface of the release material is 10 μm. It was applied and dried (100 ° C., 2 minutes) to form an adhesive layer. Thereafter, the pressure-sensitive adhesive layer was transferred to a polyethylene terephthalate film (Lumirror S10 manufactured by Toray Industries, Inc., thickness 50 μm) as a base material to obtain a base material having a pressure-sensitive adhesive layer formed on one side.

  In addition, a polyethylene terephthalate film (Lumirror S10 manufactured by Toray Industries, Inc., thickness: 250 μm) having a silicone release treatment on one side was prepared as a thickness adjusting layer.

  The above components were blended in the amounts shown in Table 1 to obtain a protective film forming layer composition. A methyl ethyl ketone solution (solid concentration 61% by mass) of the obtained composition was applied to the release-treated surface of the thickness adjusting layer so that the thickness after drying was 25 μm, dried (100 ° C., 3 minutes), and the diameter A 190 mm circular shape was cut out to obtain a laminate of a protective film forming layer and a thickness adjusting layer.

  The adhesive layer of the base material on which the pressure-sensitive adhesive layer obtained above was formed was attached to the thickness adjustment layer side of the laminate obtained above to obtain a protective film-forming sheet having the configuration shown in FIG. . In this example, t1 = 25 μm, t2 = 250 μm, and D1 = 190 mm.

(Example 2)
As a base material, a polyethylene terephthalate film (Lumirror S10 manufactured by Toray Industries, Inc., thickness 50 μm) was prepared.

  3 parts by weight of aromatic polyisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) and toluene with respect to 100 parts by weight of an acrylic copolymer based on butyl acrylate (SK Dyne 1811L, manufactured by Soken Chemical Co., Ltd.) 50 parts by weight were mixed to obtain an adhesive composition.

  Using a release material (SP-PET3811 manufactured by Lintec Corporation, thickness 38 μm, surface tension less than 30 mN / m, melting point 200 ° C. or higher), the thickness after drying the pressure-sensitive adhesive composition on the release-treated surface of the release material is 10 μm. It was applied and dried (100 ° C., 2 minutes) to form an adhesive layer. Thereafter, a polyethylene terephthalate film ((Lumirror S10 manufactured by Toray Industries, Inc., thickness 250 μm) having a silicone release treatment on one side was prepared as a resin film. The pressure-sensitive adhesive layer of the release material on which the pressure-sensitive adhesive layer obtained above was formed was transferred to the surface opposite to the release-treated surface of the resin film to obtain a thickness adjusting layer.

  The above components were blended in the amounts shown in Table 1 to obtain a protective film forming layer composition. A methyl ethyl ketone solution (solid concentration 61 mass%) of the obtained composition was applied to the release treatment surface (exfoliation treatment surface of the resin film) of the thickness adjusting layer so that the thickness after drying was 25 μm and dried (100 And a hollow body having a diameter of 190 mm was cut out to obtain a laminate of the protective film forming layer and the thickness adjusting layer.

  The base material was pasted on the thickness adjustment layer side of the laminate obtained above to obtain a protective film-forming sheet having the configuration shown in FIG. In this example, t1 = 25 μm, t2 = 260 μm, and D1 = 190 mm.

(Example 3)
Instead of the thickness adjustment layer of Example 1, a protective film was used in the same manner as in Example 1 except that a polyethylene terephthalate film (Lumirror S10 manufactured by Toray Industries, Inc., thickness 342 μm) on one side was used. A forming sheet was obtained. In this example, t1 = 25 μm, t2 = 342 μm, and D1 = 190 mm.

Example 4
In place of the resin film of Example 2, a protective film was formed in the same manner as in Example 2 except that a polyethylene terephthalate film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 342 μm) on one side was used. A sheet was obtained. In this example, t1 = 25 μm, t2 = 352 μm, and D1 = 190 mm.

(Example 5)
For forming the protective film of Example 1 except that instead of the thickness adjusting layer of Example 1, a polyethylene terephthalate film (Lumirror S10 manufactured by Toray Industries, Inc., thickness 188 μm) subjected to silicone-based release treatment on one side was used. A sheet having the same configuration as the sheet was obtained and used as an intermediate material for forming a protective film.

  3 parts of aromatic polyisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) and 50 parts of toluene with respect to 100 parts of acrylic copolymer (SK Dyne 1811L, manufactured by Soken Chemical Co., Ltd.) based on butyl acrylate Were mixed to obtain a pressure-sensitive adhesive composition.

  Using a release material (SP-PET3811 manufactured by LINTEC, thickness 38 μm, surface tension less than 30 mN / m, melting point 200 ° C. or higher), the thickness after drying the pressure-sensitive adhesive composition on the release-treated surface of the release material The pressure-sensitive adhesive layer was formed by coating and drying (100 ° C., 2 minutes) so as to be 15 μm. Thereafter, the pressure-sensitive adhesive layer was transferred to a polyethylene terephthalate film (Lumilar S10 manufactured by Toray Industries, Inc., thickness 50 μm) as a base material, and this was cut into a circle having a diameter of 190 mm to form a pressure-sensitive adhesive layer on one side. A back surface thickness adjusting layer was obtained. The pressure-sensitive adhesive layer of the back surface thickness adjusting layer is affixed to a region opposite to the thickness adjusting layer forming surface of the base material of the protective film forming sheet intermediate material and corresponding to the thickness adjusting layer. A protective film-forming sheet with an adjustment layer was obtained. In this example, t1 = 25 μm, t2 = 188 μm, t3 = 65 μm, and D1 = 190 mm.

(Example 6)
A protective film-forming sheet was obtained in the same manner as in Example 1 except that the diameter of the laminate of the protective film-forming layer and the thickness adjusting layer was 200 mm. In this example, D1 = 200 mm.

(Comparative Example 1)
A protective film-forming sheet was obtained in the same manner as in Example 1 except that the thickness adjusting layer was not provided and the protective film-forming layer was directly provided on the substrate.

  Using the obtained protective film-forming sheet, <paste evaluation> and <aeration length evaluation> were performed. Table 1 shows t1 + t2, D1, and evaluation results.

DESCRIPTION OF SYMBOLS 1 ... Protective film formation layer 2 ... Base material 3 ... Thickness adjustment layer 4 ... Adhesive layer 5 ... Resin film 6 ... Adhesive layer 10 ... Laminated film 100 ... Protective film formation sheet 11 ... Semiconductor wafer (wafer)
12 ... Semiconductor chip (chip)
DESCRIPTION OF SYMBOLS 13 ... Circuit 14 ... Circuit surface inner peripheral part 15 ... Surplus part 16 ... Back inner peripheral part 17 ... Ring-shaped convex part

Claims (7)

  The protective film formation sheet which has the protective film formation layer formed in the peelable form on the convex part of the laminated film which has a circular convex part.   The protective film-forming sheet according to claim 1, wherein the laminated film comprises a base material and a thickness adjusting layer, and the thickness adjusting layer is a circular convex portion.   The protective film-forming sheet according to claim 1 or 2, which is used for forming a protective film on the inner peripheral portion of the back surface of a semiconductor wafer having a circuit formed on the front surface and an annular convex portion on the outer peripheral portion of the back surface.   The protection according to claim 3, wherein the thickness t1 of the protective film forming layer, the thickness t2 of the circular convex portion, and the step T3 between the inner peripheral portion of the back surface of the semiconductor wafer and the annular convex portion satisfy a relationship of t1 + t2 ≧ T3. Film forming sheet.   5. A semiconductor wafer according to claim 3, wherein the inner peripheral portion of the rear surface of the semiconductor wafer is circular, and the diameter D1 of the top surface of the circular convex portion and the diameter D2 of the inner peripheral portion of the rear surface of the semiconductor wafer satisfy the relationship of D1 ≦ D2. The protective film-forming sheet according to any one of the above.   The back surface thickness adjustment layer is provided on the opposite surface of the circular projection in the laminated film, the thickness t3 of the back surface thickness adjustment layer, the thickness t1 of the protective film forming layer, the thickness t2 of the circular projection, and the semiconductor The protective film forming sheet according to any one of claims 3 to 5, wherein the step T3 between the inner peripheral portion of the back surface of the wafer and the annular convex portion satisfies a relationship of t1 + t2 + t3 ≧ T3. A semiconductor chip comprising a step of affixing the protective film-forming sheet according to any one of claims 1 to 6 on a rear inner peripheral portion of a semiconductor wafer having a circuit formed on the front surface and an annular convex portion on a rear outer peripheral portion. Production method.

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