JP2018037667A - Composite sheet for protection film formation and laser printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a protection coat-forming film which enables the formation of a protection film arranged so as to allow an inspection to be performed about a crack or the like in a work or a product obtained by processing a work concerned, and to make a grinding trace in the work or such product invisible; and a (composite) sheet for protection film formation.SOLUTION: A sheet 2 for protection film formation comprises: a protection coat-forming film 1 of which the transmittance of light of a wavelength of 1600 nm is 25-90% and the transmittance of light of a wavelength of 550 nm is 20% or less; and a peelable sheet 21 laminated on one or each face of the protection coat-forming film 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a protective film-forming film and a protective film-forming (composite) sheet that can form a protective film on a workpiece such as a semiconductor wafer or a workpiece (for example, a semiconductor chip) obtained by processing the workpiece, and the like The present invention relates to an inspection method for inspecting a workpiece or a workpiece with a protective film obtained by using the above.

  In recent years, a semiconductor device is manufactured by a mounting method called a face-down method. In this method, when a semiconductor chip having a circuit surface on which electrodes such as bumps are formed is mounted, the circuit surface side of the semiconductor chip is bonded to a chip mounting portion such as a lead frame. Therefore, the back surface side of the semiconductor chip on which no circuit is formed is exposed.

  For this reason, a protective film made of a hard organic material is often formed on the back side of the semiconductor chip to protect the semiconductor chip. This protective film is formed using, for example, a film for semiconductor back surface or a dicing tape integrated wafer back surface protective film as disclosed in Patent Document 1 or 2.

  In the film for semiconductor back surface in Patent Document 1, the light transmittance at a wavelength of 532 nm or 1064 nm is set to 20% or less. This enables printing processing by laser light irradiation and prevents the semiconductor element from being adversely affected by the laser light. Moreover, in the wafer back surface protective film in Patent Document 2, the visible light transmittance is set to 20% or less. Thereby, the influence on the semiconductor element due to the passage of light is reduced.

JP 2012-28396 A JP 2012-235168 A

  By the way, in a semiconductor chip or the like obtained by dicing a semiconductor wafer, a crack or the like may be generated due to stress generated during processing. However, when the protective film having the light transmittance as described above is formed, cracks and the like generated on the protective film side of the semiconductor chip cannot be found visually. A semiconductor chip with cracks that cannot be overlooked reduces the product yield.

  On the other hand, grinding marks are usually left on the back surface of the semiconductor chip by back grinding applied to the semiconductor wafer. From the viewpoint of the appearance of the semiconductor chip, it is desirable that such grinding marks are not visible with the naked eye, and are preferably hidden by the protective film.

  The present invention has been made in view of the actual situation as described above, and is capable of inspecting a crack or the like existing in a workpiece or a workpiece obtained by processing the workpiece, and is present in the workpiece or the workpiece. Inspection of protective film-forming film and protective film-forming (composite) sheet capable of forming a protective film in which grinding marks are not visible by visual inspection, and a workpiece or a workpiece with a protective film obtained by using them The purpose is to provide an inspection method.

  In order to achieve the above object, first, the present invention provides a protective film-forming film characterized in that the light transmittance at a wavelength of 1600 nm is 25% or more and the light transmittance at a wavelength of 550 nm is 20% or less. Provided (Invention 1)

  According to the said invention (invention 1), the inspection by infrared rays, such as a crack which exists in a workpiece | work or the workpiece obtained by processing the said workpiece | work, is possible, and the grinding trace which exists in a workpiece | work or a workpiece can be seen visually. No protective film can be formed.

  In the said invention (invention 1), it is preferable that the said protective film formation film is a single layer comprised from an uncured curable adhesive (invention 2).

  In the said invention (invention 2), it is preferable that the said curable adhesive contains a coloring agent and a filler with an average particle diameter of 0.01-3 micrometers (invention 3).

  2ndly, this invention was equipped with the said protective film formation film (invention 1-3) and the peeling sheet laminated | stacked on the one or both surfaces of the said protective film formation film. A sheet is provided (Invention 4).

  3rdly, this invention is a protective film provided with the adhesive sheet by which an adhesive layer is laminated | stacked on the one surface side of a base material, and the protective film formation film laminated | stacked on the said adhesive layer side of the said adhesive sheet A composite sheet for forming, wherein the protective film-forming film has a light transmittance of 1600 nm at a wavelength of 25% or more, and the protective film-forming film has a light transmittance of 550 nm at a wavelength of 10% or less. A composite sheet for forming a protective film is provided (Invention 5).

  According to the above inventions (Inventions 4 and 5), it is possible to inspect by infrared rays such as cracks existing in a workpiece or a workpiece obtained by processing the workpiece, and grinding marks existing in the workpiece or workpiece are visually observed. A protective film that cannot be seen can be formed.

  In the said invention (invention 5), it is preferable that the said protective film formation film is a single layer comprised from an uncured curable adhesive (invention 6).

  In the said invention (invention 6), it is preferable that the said curable adhesive contains a coloring agent and a filler with an average particle diameter of 0.01-3 micrometers (invention 7).

  4thly, this invention protects a workpiece | work using the said protective film formation film (Invention 1-3), the said protective film formation sheet (Invention 4), or the said protective film formation composite sheet (Invention 5-7). By forming a film, a workpiece with a protective film is manufactured, and the workpiece obtained by processing the workpiece with the protective film or the workpiece with the protective film is inspected through the protective film using infrared rays. An inspection method characterized in that it is performed (Invention 8).

  In the said invention (invention 8), it is preferable that the said workpiece | work is a semiconductor wafer and the said workpiece is a semiconductor chip (invention 9).

  5thly this invention provides the workpiece | work with a protective film determined to be non-defective based on the said inspection method (invention 8 and 9) (invention 10).

  Sixth, the present invention provides a processed product determined as a non-defective product based on the inspection method (Inventions 8 and 9) (Invention 11).

  According to the protective film-forming film and protective film-forming (composite) sheet according to the present invention, inspection by infrared rays such as cracks existing in a workpiece or a workpiece obtained by processing the workpiece is possible, and the workpiece or It is possible to form a protective film in which grinding marks existing on the workpiece are not visible by visual inspection. Further, according to the inspection method of the present invention, it is possible to inspect a crack or the like existing in a workpiece or a workpiece by using infrared rays.

It is sectional drawing of the sheet | seat for protective film formation which concerns on one Embodiment of this invention. It is sectional drawing of the composite sheet for protective film formation which concerns on one Embodiment of this invention. It is sectional drawing of the composite sheet for protective film formation which concerns on other embodiment of this invention. It is sectional drawing which shows the usage example of the composite sheet for protective film formation which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
[Protective film forming film]
The protective film-forming film according to this embodiment is for forming a protective film on a workpiece or a workpiece obtained by processing the workpiece. This protective film is composed of a protective film-forming film, preferably a cured protective film-forming film. Examples of the workpiece include a semiconductor wafer, and examples of a workpiece obtained by processing the workpiece include a semiconductor chip. However, the present invention is not limited to these. When the work is a semiconductor wafer, the protective film is formed on the back side of the semiconductor wafer (the side on which no electrodes such as bumps are formed).

1. Physical Properties The protective film-forming film according to this embodiment has a light transmittance at a wavelength of 1600 nm of 25% or more and a light transmittance at a wavelength of 550 nm of 20% or less. The light transmittance in this specification is a value measured without using an integrating sphere, and a spectrophotometer is used as a measuring instrument.

  In a semiconductor chip or the like obtained by dicing a semiconductor wafer, a crack or the like may occur due to stress generated during processing. As described above, when the light transmittance at a wavelength of 1600 nm is 25% or more, infrared transmittance is improved, and infrared rays are obtained from the protective film forming film (or the protective film formed by the protective film forming film) side. Infrared inspection can be performed. Thereby, the crack etc. in workpieces, such as a semiconductor chip, can be discovered through a protective film formation film (protective film), and a product yield can be improved.

  From the viewpoint of infrared transparency, the light transmittance at a wavelength of 1600 nm of the protective film-forming film is preferably 40% or more, particularly preferably 45% or more, and more preferably 50% or more. . In addition, although the upper limit of the light transmittance of wavelength 1600nm is not specifically limited, By setting the light transmittance of wavelength 550nm to 20% or less, it will be decided naturally. Further, when using a workpiece (semiconductor chip or the like) on which a protective film is formed, the protective film-forming film has a light transmittance at a wavelength of 1600 nm of 90% or less, so that the workpiece easily affected by infrared rays from the outside can be obtained. Malfunction can be prevented.

  On the other hand, for example, on the back surface of the semiconductor chip, grinding marks are usually left by back grinding processing applied to the semiconductor wafer. When the light transmittance at a wavelength of 550 nm is 20% or less as described above, the protective film-forming film is difficult to transmit visible light. Therefore, the above-mentioned grinding mark is concealed by the protective film forming film (protective film) and hardly visible by visual inspection. Thereby, the external appearance of workpieces, such as a semiconductor chip, will be excellent.

  From the viewpoint of the grinding mark concealing property, the light transmittance at a wavelength of 550 nm of the protective film-forming film is preferably 15% or less, and particularly preferably 10% or less. The lower limit of the light transmittance at a wavelength of 550 nm is not particularly limited, but is naturally determined by setting the light transmittance at a wavelength of 1600 nm to 25% or more.

  Here, the protective film-forming film according to the present embodiment may be composed of a single layer or may be composed of a plurality of layers. It is preferable that it consists of a single layer from the surface. When the protective film-forming film is composed of a plurality of layers, it is preferable that the light transmittance is satisfied as a whole of the plurality of layers from the viewpoint of easy control of the light transmittance.

2. Material The protective film-forming film is preferably made of an uncured curable adhesive. In this case, after the workpiece such as a semiconductor wafer is overlaid on the protective film forming film, the protective film forming film is cured, so that the protective film can be firmly adhered to the work, and the durable protective film is formed into a chip. Etc. can be formed.

  In addition, when a protective film formation film consists of an uncured curable adhesive, the light transmittance of the said protective film formation film hardly changes even before and after hardening. Therefore, if the light transmittance at a wavelength of 1600 nm of the protective film-forming film before curing is 25% or more and the light transmittance at a wavelength of 550 nm is 20% or less, the wavelength of the protective film-forming film (protective film) after curing is 1600 nm. The light transmittance is 25% or more, and the light transmittance at a wavelength of 550 nm is 20% or less.

  The protective film-forming film preferably has adhesiveness at room temperature or exhibits adhesiveness by heating. Thereby, both can be bonded together when a workpiece such as a semiconductor wafer is superimposed on the protective film forming film as described above. Therefore, positioning can be reliably performed before the protective film forming film is cured.

  The curable adhesive constituting the protective film-forming film having the above properties preferably contains a curable component and a binder polymer component. As the curable component, a thermosetting component, an energy ray curable component, or a mixture thereof can be used, but it is particularly preferable to use a thermosetting component. This is because the protective film-forming film has the light transmittance described above, and thus becomes unsuitable for ultraviolet curing and is desirably thermosetting.

  Examples of the thermosetting component include epoxy resins, phenol resins, melamine resins, urea resins, polyester resins, urethane resins, acrylic resins, polyimide resins, benzoxazine resins, and mixtures thereof. Among these, an epoxy resin, a phenol resin, and a mixture thereof are preferably used.

  Epoxy resins have the property of forming a three-dimensional network upon heating and forming a strong film. As such an epoxy resin, conventionally known various epoxy resins are used. Usually, those having a molecular weight of about 300 to 2000 are preferred, and those having a molecular weight of 300 to 500 are particularly preferred. Furthermore, it is preferably used in a form in which a normal epoxy resin having a molecular weight of 330 to 400 is blended with an epoxy resin solid at room temperature having a molecular weight of 400 to 2500, particularly 500 to 2000. Moreover, it is preferable that the epoxy equivalent of an epoxy resin is 50-5000 g / eq.

  Specific examples of such epoxy resins include glycidyl ethers of phenols such as bisphenol A, bisphenol F, resorcinol, phenyl novolac, and cresol novolac; glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; Glycidyl ethers of carboxylic acids such as phthalic acid, isophthalic acid, tetrahydrophthalic acid; glycidyl type or alkyl glycidyl type epoxy resins in which active hydrogen bonded to nitrogen atom such as aniline isocyanurate is substituted with glycidyl group; vinylcyclohexane diepoxide; 3,4-epoxycyclohexylmethyl-3,4-dicyclohexanecarboxylate, 2- (3,4-epoxy) cyclohexyl-5,5-spiro (3,4 As the epoxy) cyclohexane -m- dioxane, carbon in the molecule - epoxy is introduced by for example oxidation to carbon double bond include a so-called alicyclic epoxides. In addition, an epoxy resin having a biphenyl skeleton, a dicyclohexadiene skeleton, a naphthalene skeleton, or the like can also be used.

  Among these, bisphenol glycidyl type epoxy resins, o-cresol novolac type epoxy resins and phenol novolak type epoxy resins are preferably used. These epoxy resins can be used alone or in combination of two or more.

  When using an epoxy resin, it is preferable to use a thermally activated latent epoxy resin curing agent in combination as an auxiliary agent. The thermally activated latent epoxy resin curing agent is a type of curing agent that does not react with the epoxy resin at room temperature but is activated by heating at a certain temperature or more and reacts with the epoxy resin. The heat activated latent epoxy resin curing agent is activated by a method in which active species (anions and cations) are generated by a chemical reaction by heating; the epoxy resin is stably dispersed in the epoxy resin at around room temperature and is heated at a high temperature. There are a method of initiating a curing reaction by dissolving and dissolving with a solvent; a method of starting a curing reaction by elution at a high temperature with a molecular sieve encapsulated type curing agent; a method using a microcapsule and the like.

  Specific examples of the thermally activated latent epoxy resin curing agent include various onium salts, high melting point active hydrogen compounds such as dibasic acid dihydrazide compounds, dicyandiamides, amine adduct curing agents, and imidazole compounds. These thermally activated latent epoxy resin curing agents can be used singly or in combination of two or more. The thermally activated latent epoxy resin curing agent as described above is preferably from 0.1 to 20 parts by weight, particularly preferably from 0.2 to 10 parts by weight, more preferably from 0.1 to 100 parts by weight based on 100 parts by weight of the epoxy resin. It is used at a ratio of 3 to 5 parts by weight.

  As the phenolic resin, a condensate of phenols such as alkylphenol, polyhydric phenol, naphthol and aldehydes is used without particular limitation. Specifically, phenol novolak resin, o-cresol novolak resin, p-cresol novolak resin, t-butylphenol novolak resin, dicyclopentadiene cresol resin, polyparavinylphenol resin, bisphenol A type novolak resin, or modified products thereof Etc. are used.

  The phenolic hydroxyl group contained in these phenolic resins can easily undergo an addition reaction with the epoxy group of the epoxy resin by heating to form a cured product having high impact resistance. For this reason, you may use together an epoxy resin and a phenol-type resin.

  The binder polymer component can give an appropriate tack to the protective film-forming film and improve the operability of the protective film-forming composite sheet 3. The weight average molecular weight of the binder polymer is usually 50,000 to 2,000,000, preferably 100,000 to 1,500,000, particularly preferably 200,000 to 1,000,000. When the molecular weight is too low, film formation of the protective film-forming film becomes insufficient, and when it is too high, compatibility with other components is deteriorated, and as a result, uniform film formation is prevented. As such a binder polymer, for example, an acrylic polymer, a polyester resin, a phenoxy resin, a urethane resin, a silicone resin, a rubber polymer, and the like are used, and an acrylic polymer is particularly preferably used.

  Examples of the acrylic polymer include (meth) acrylic acid ester copolymers composed of (meth) acrylic acid ester monomers and structural units derived from (meth) acrylic acid derivatives. Here, the (meth) acrylic acid ester monomer is preferably a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) Propyl acrylate, butyl (meth) acrylate, etc. are used. Examples of the (meth) acrylic acid derivative include (meth) acrylic acid, glycidyl (meth) acrylate, hydroxyethyl (meth) acrylate, and the like.

  Among them, when glycidyl group is introduced into an acrylic polymer using glycidyl methacrylate as a structural unit, the compatibility with the epoxy resin as the thermosetting component described above is improved, and the glass after curing of the protective film-forming film The transition temperature (Tg) is increased and the heat resistance is improved. In addition, among the above, when a hydroxyl group is introduced into an acrylic polymer using hydroxyethyl acrylate or the like as a structural unit, adhesion to a workpiece and physical properties of an adhesive can be controlled.

  When an acrylic polymer is used as the binder polymer, the weight average molecular weight of the polymer is preferably 100,000 or more, and particularly preferably 150,000 to 1,000,000. The glass transition temperature of the acrylic polymer is usually 20 ° C. or less, preferably about −70 to 0 ° C., and has adhesiveness at room temperature (23 ° C.).

  The blending ratio of the thermosetting component and the binder polymer component is preferably 50 to 1500 parts by weight, particularly preferably 70 to 1000 parts by weight, more preferably 100 parts by weight of the binder polymer component. It is preferable to blend 80 to 800 parts by weight. When the thermosetting component and the binder polymer component are blended in such a ratio, an appropriate tack is exhibited before curing, and the sticking operation can be stably performed. A membrane is obtained.

  The protective film-forming film preferably contains a colorant and / or a filler, and particularly preferably contains both a colorant and a filler. Thereby, it becomes possible to control the light transmittance of the wavelength 1600 nm and the wavelength 550 nm within the above-described ranges. Moreover, when a protective film formation film contains a filler, while being able to maintain the hardness of the protective film after hardening high, moisture resistance can be improved. Furthermore, the thermal expansion coefficient of the protective film after curing can be brought close to the thermal expansion coefficient of the semiconductor wafer, thereby reducing the warpage of the semiconductor wafer during processing.

  As the colorant, for example, known pigments such as inorganic pigments, organic pigments, and organic dyes can be used, but inorganic pigments are preferably used from the viewpoint of controllability of light transmittance.

  Examples of inorganic pigments include carbon black, cobalt dyes, iron dyes, chromium dyes, titanium dyes, vanadium dyes, zirconium dyes, molybdenum dyes, ruthenium dyes, platinum dyes, ITO (indium) Tin oxide) dyes, ATO (antimony tin oxide) dyes, and the like.

  Examples of organic pigments and organic dyes include aminium dyes, cyanine dyes, merocyanine dyes, croconium dyes, squalium dyes, azurenium dyes, polymethine dyes, naphthoquinone dyes, pyrylium dyes, and phthalocyanine dyes. Dyes, naphthalocyanine dyes, naphtholactam dyes, azo dyes, condensed azo dyes, indigo dyes, perinone dyes, perylene dyes, dioxazine dyes, quinacridone dyes, isoindolinone dyes, quinophthalone dyes, Pyrrole dyes, thioindigo dyes, metal complex dyes (metal complex dyes), dithiol metal complex dyes, indolephenol dyes, triallylmethane dyes, anthraquinone dyes, dioxazine dyes, naphthol dyes, azomethine dyes The Zuimidazoron based dyes, pyranthrone pigments and threne color like. These pigments or dyes can be appropriately mixed and used in order to adjust to the desired light transmittance.

  Among the above, it is particularly preferable to use carbon black. According to carbon black, it is easy to control the light transmittance at a wavelength of 1600 nm and a wavelength of 550 nm within the above-described ranges.

  The blending amount of the colorant (particularly carbon black) in the protective film-forming film varies depending on the thickness of the protective film-forming film. For example, when the thickness of the protective film-forming film is 25 μm, 0.05 to 1 mass is used. %, Preferably 0.075 to 0.75% by mass, more preferably 0.1 to 0.5% by mass. When the blending amount of the colorant is 0.05% by mass or more, it is easy to control the light transmittance at a wavelength of 550 nm to 20% or less so that grinding marks on the semiconductor chip or the like cannot be visually observed. On the other hand, if the blending amount of the colorant exceeds 1% by mass, infrared rays may not pass through the protective film-forming film (protective film), and infrared inspection may not be possible. As the thickness of the protective film-forming film decreases, the light transmittance tends to increase. When the thickness of the protective film-forming film increases, the light transmittance tends to decrease. It is desirable to adjust the blending amount of the colorant as appropriate according to the thickness. Specifically, it is desirable to adjust so that the thickness of the protective film-forming film and the blending amount of the colorant have an inversely proportional relationship.

  The average particle diameter of the colorant (particularly carbon black) is preferably 1 to 500 nm, particularly preferably 3 to 100 nm, and further preferably 5 to 50 nm. When the average particle diameter of the colorant is within the above range, the light transmittance at a wavelength of 550 nm and the light transmittance at a wavelength of 1600 nm can be easily controlled within the above-described ranges. In addition, the average particle diameter of the colorant in this specification is a value measured by a dynamic light scattering method using a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Nanotrack Wave-UT151).

  Examples of the filler include silica such as crystalline silica, fused silica, and synthetic silica, and inorganic filler such as alumina and glass balloon. Among these, silica is preferable, synthetic silica is more preferable, and synthetic silica of the type in which α-ray sources that cause malfunction of the semiconductor device are removed as much as possible is optimal. Examples of the shape of the filler include a spherical shape, a needle shape, and an indefinite shape, and a spherical shape is preferable, and a true spherical shape is particularly preferable. When the filler is spherical or true spherical, irregular reflection of light hardly occurs, and the above-described infrared inspection can be performed satisfactorily.

  Moreover, as a filler added to a protective film formation film, a functional filler other than the said inorganic filler may be mix | blended. As the functional filler, for example, a conductive filler in which gold, silver, copper, nickel, aluminum, stainless steel, carbon, ceramic, nickel, aluminum, or the like is coated with silver for the purpose of imparting conductivity after die bonding. And metal materials such as gold, silver, copper, nickel, aluminum, stainless steel, silicon, and germanium, and heat conductive fillers such as alloys thereof for the purpose of imparting thermal conductivity.

  The average particle size of the filler (particularly silica filler) is preferably 0.01 to 10 μm, more preferably 0.01 to 3 μm, particularly preferably 0.03 to 2 μm, and further 0 It is preferable that it is 0.05-1 micrometer. When the average particle size of the filler is 0.01 μm or more, it is easy to control the light transmittance at a wavelength of 550 nm to 20% or less so that grinding marks on a semiconductor chip or the like cannot be seen visually. On the other hand, when the average particle diameter of the filler exceeds 10 μm, the surface state of the protective film-forming film may be deteriorated. Moreover, when the average particle diameter of a filler exceeds 3 micrometers, it may be difficult to carry out an infrared test by irregular reflection of infrared rays. In addition, let the average particle diameter below 1 micrometer of the filler in this specification be the value measured by the dynamic light-scattering method using the particle size distribution measuring apparatus (The Nikkiso Co., Ltd. make, Nanotrack Wave-UT151). The average particle size of 1 μm or more of the filler is a value measured by a laser diffraction / scattering method using a particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., Microtrac MT3000II).

  The amount of filler (especially silica filler) in the protective film-forming film is preferably 10 to 80% by mass, particularly preferably 20 to 70% by mass, and more preferably 30 to 65% by mass. Is preferred. When the blending amount of the filler is 10% by mass or more, it is easy to control the light transmittance at a wavelength of 550 nm to 20% or less so that grinding marks on a semiconductor chip or the like cannot be visually observed. On the other hand, if the blending amount of the filler exceeds 80% by mass, infrared rays may not pass through the protective film-forming film (protective film), and infrared inspection may not be possible.

  The protective film-forming film may contain a coupling agent. By containing the coupling agent, after curing of the protective film-forming film, it is possible to improve the adhesion and adhesion between the protective film and the workpiece without impairing the heat resistance of the protective film, (Moisture and heat resistance) can be improved. As the coupling agent, a silane coupling agent is preferable because of its versatility and cost merit.

  Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacryloxy). Propyl) 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, methyltri Methoxysilane , Methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These can be used individually by 1 type or in mixture of 2 or more types.

  The protective film-forming film may contain a crosslinking agent such as an organic polyvalent isocyanate compound, an organic polyvalent imine compound, or an organometallic chelate compound in order to adjust the cohesive force before curing. Further, the protective film-forming film may contain an antistatic agent in order to suppress static electricity and improve the reliability of the chip. Furthermore, the protective film-forming film may contain a flame retardant such as a phosphoric acid compound, a bromine compound, or a phosphorus compound in order to enhance the flame retardance performance of the protective film and improve the reliability as a package.

  The thickness of the protective film-forming film is preferably 3 to 300 μm, particularly preferably 5 to 200 μm, and more preferably 7 to 100 μm in order to effectively exert the function as the protective film. Is preferred.

[Protective film forming sheet]
FIG. 1 is a cross-sectional view of a protective film forming sheet according to an embodiment of the present invention. As shown in FIG. 1, the protective film-forming sheet 2 according to this embodiment includes a protective film-forming film 1 and a release layer laminated on one surface (the lower surface in FIG. 1) of the protective film-forming film 1. And a sheet 21. However, the release sheet 21 is peeled off when the protective film forming sheet 2 is used.

  The release sheet 21 protects the protective film-forming film 1 until the protective film-forming sheet 2 is used, and is not necessarily required. The configuration of the release sheet 21 is arbitrary, and examples thereof include a plastic film in which the film itself is peelable from the protective film-forming film 1 and a film obtained by peeling the plastic film with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based, and the like can be used, and among these, a silicone-based material that is inexpensive and provides stable performance is preferable. Although there is no restriction | limiting in particular about the thickness of the peeling sheet 21, Usually, it is about 20-250 micrometers.

  The release sheet 21 as described above may also be laminated on the other surface (the upper surface in FIG. 1) of the protective film-forming film 1. In this case, it is preferable that the release force of one release sheet 21 is increased to obtain a heavy release release sheet, and the release force of the other release sheet 21 is reduced to provide a light release release sheet.

  In order to manufacture the protective film-forming sheet 2 according to the present embodiment, the release surface of the release sheet 21 (a surface having peelability; usually a surface subjected to a release treatment, but is not limited thereto). A protective film forming film 1 is formed. Specifically, a coating agent for a protective film-forming film containing a curable adhesive constituting the protective film-forming film 1 and, if desired, further a solvent is prepared, and a roll coater, a knife coater, a roll knife coater, an air knife The protective film-forming film 1 is formed by applying to the release surface of the release sheet 21 with a coating machine such as a coater, die coater, bar coater, gravure coater, curtain coater, and drying.

  As an example, a method for manufacturing a chip with a protective film from a semiconductor wafer as a workpiece using the protective film forming sheet 2 according to the present embodiment will be described below. First, the protective film forming film 1 of the protective film forming sheet 2 is attached to the back surface of the semiconductor wafer having a circuit formed on the front surface and subjected to back grinding. At this time, if desired, the protective film-forming film 1 may be heated to exhibit adhesiveness.

  Next, the release sheet 21 is peeled from the protective film forming film 1. Thereafter, the protective film forming film 1 is cured to form a protective film, and a semiconductor wafer with a protective film is obtained. When the protective film forming film 1 is a thermosetting adhesive, the protective film forming film 1 may be heated at a predetermined temperature for an appropriate time. In addition, you may perform hardening of the protective film formation film 1 after a dicing process.

  If a semiconductor wafer with a protective film is obtained as described above, the protective film is irradiated with laser light as desired to perform laser printing. In addition, you may perform this laser printing before hardening of the protective film formation film 1. FIG.

  Next, using a desired dicing sheet, the semiconductor wafer with a protective film is diced according to a conventional method to obtain a chip having a protective film (chip with a protective film). Thereafter, if necessary, the dicing sheet is expanded in the plane direction, and a chip with a protective film is picked up from the dicing sheet.

  The chip with a protective film obtained as described above is excellent in appearance because grinding marks by back grinding are hidden by the protective film and cannot be visually observed. Moreover, since the chip | tip with a protective film and the semiconductor wafer with a protective film can perform an infrared test through a protective film, a crack etc. can be discovered by an infrared test and a product yield can be improved.

  The infrared inspection is an inspection performed using infrared rays, and by acquiring infrared rays from a workpiece such as a semiconductor wafer with a protective film or a workpiece such as a chip with a protective film through the protective film. It can be carried out. The wavelength of infrared rays to be acquired is usually 800 to 2800 nm, preferably 1100 to 2100 nm. As an infrared inspection apparatus, a known apparatus such as an infrared camera or an infrared microscope can be used.

[Composite sheet for protective film formation]
FIG. 2 is a cross-sectional view of a protective film-forming composite sheet according to an embodiment of the present invention. As shown in FIG. 2, the protective film-forming composite sheet 3 according to this embodiment includes a pressure-sensitive adhesive sheet 4 in which a pressure-sensitive adhesive layer 42 is laminated on one surface of a substrate 41, and a pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet 4. The protective film forming film 1 laminated on the 42 side and the jig adhesive layer 5 laminated on the peripheral edge of the protective film forming film 1 opposite to the adhesive sheet 4 are configured. The jig pressure-sensitive adhesive layer 5 is a layer for bonding the protective film-forming composite sheet 3 to a jig such as a ring frame.

  When processing a workpiece, the composite sheet 3 for forming a protective film according to the embodiment is attached to the workpiece and holds the workpiece, and a protective film is applied to the workpiece or a workpiece obtained by processing the workpiece. Used to form. This protective film is composed of a protective film-forming film 1, preferably a cured protective film-forming film 1.

  As an example, the composite sheet 3 for forming a protective film according to the embodiment is used to hold a semiconductor wafer during dicing processing of a semiconductor wafer as a workpiece and to form a protective film on a semiconductor chip obtained by dicing. It is not limited to this. In this case, the adhesive sheet 4 of the protective film-forming composite sheet 3 is generally referred to as a dicing sheet.

1. Adhesive Sheet The adhesive sheet 4 of the protective film-forming composite sheet 3 according to the present embodiment includes a base material 41 and an adhesive layer 42 laminated on one surface of the base material 41.

1-1. The base material 41 of the pressure-sensitive adhesive sheet 4 is not particularly limited as long as it is suitable for workpiece processing, for example, dicing and expanding of a semiconductor wafer. Usually, a resin-based material is used as a main material. It is comprised from a film (henceforth "resin film").

  Specific examples of resin films include polyethylene films such as low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, and high density polyethylene (HDPE) films, polypropylene films, polybutene films, polybutadiene films, and polymethylpentene films. Polyolefin films such as ethylene-norbornene copolymer film and norbornene resin film; ethylene-vinyl acetate copolymer film, ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) acrylic acid ester copolymer Ethylene copolymer film such as film; Polyvinyl chloride film such as polyvinyl chloride film and vinyl chloride copolymer film; Polyethylene terephthalate film, Polybutylene tele Polyester film of tallate films; polyurethane film; polyimide film; polystyrene films; polycarbonate films; and fluorine resin film. Further, modified films such as these crosslinked films and ionomer films are also used. The substrate 41 may be a film made of one of these, or may be a laminated film in which two or more of these are combined. In addition, “(meth) acrylic acid” in the present specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

  Among these, from the viewpoints of environmental safety, cost, and the like, a polyolefin film is preferable, and among them, a polypropylene film excellent in heat resistance is preferable. If it is a polypropylene film, heat resistance can be provided to the base material 41, without impairing the expandability of the adhesive sheet 4, and the pick-up property of a chip | tip. Due to the heat resistance of the base material 41, even when the protective film forming film 1 is heat-cured in a state where the protective film forming composite sheet 3 is attached to a work, the occurrence of loosening of the adhesive sheet 4 is suppressed. be able to.

  The resin film may be subjected to a surface treatment such as an oxidation method or a concavo-convex method or a primer treatment on one or both sides as desired for the purpose of improving the adhesion with the pressure-sensitive adhesive layer 42 laminated on the surface. it can. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, and the like. Examples include a thermal spraying method.

  The base material 41 may contain various additives such as a colorant, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and a filler in the resin film.

  The thickness of the base material 41 is not particularly limited as long as it can function properly in each process in which the protective film-forming composite sheet 3 is used. Preferably it is 20-450 micrometers, More preferably, it is 25-400 micrometers, Most preferably, it is the range of 50-350 micrometers.

  The breaking elongation of the base material 41 of the pressure-sensitive adhesive sheet 4 in this embodiment is preferably 100% or more as a value measured at 23 ° C. and a relative humidity of 50%, particularly preferably 200 to 1000%. . Here, the breaking elongation is an elongation ratio of the length of the test piece at the time of breaking the test piece with respect to the original length in the tensile test based on JIS K7161: 1994 (ISO 527-1 1993). The base material 41 having a breaking elongation of 100% or more is not easily broken during the expanding process, and the chips formed by cutting the workpiece can be easily separated.

  Moreover, it is preferable that the tensile stress at the time of 25% distortion of the base material 41 of the adhesive sheet 4 in this embodiment is 5-15 N / 10mm, and it is preferable that a maximum tensile stress is 15-50 MPa. Here, the tensile stress at the time of 25% strain and the maximum tensile stress are measured by a test according to JIS K7161: 1994. When the tensile stress at 25% strain is 5 N / 10 mm or more and the maximum tensile stress is 15 MPa or more, the base material 2 is loosened when the workpiece is bonded to the dicing sheet 1 and then fixed to a frame such as a ring frame. Generation | occurrence | production is suppressed and it can prevent that a conveyance error arises. On the other hand, when the tensile stress at 25% strain is 15 N / 10 mm or less and the maximum tensile stress is 50 MPa or less, the dicing sheet 1 itself is prevented from peeling off from the ring frame during the expanding process. The elongation at break, the tensile stress at 25% strain, and the maximum tensile stress are values measured in the longitudinal direction of the original fabric in the base material 41.

1-2. The pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 42 provided in the pressure-sensitive adhesive sheet 4 of the composite sheet 3 for forming a protective film according to the present embodiment may be composed of a non-energy ray curable pressure sensitive adhesive or may be composed of an energy ray curable pressure sensitive adhesive. May be. As the non-energy ray curable pressure-sensitive adhesive, those having desired adhesive strength and removability are preferable. For example, acrylic pressure-sensitive adhesive, rubber-based pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, and polyester-based pressure-sensitive adhesive Polyvinyl ether-based pressure-sensitive adhesives can be used. Among these, an acrylic pressure-sensitive adhesive that has high adhesiveness with the protective film-forming film 1 and can effectively prevent the workpiece or workpiece from falling off in a dicing process or the like is preferable.

  On the other hand, the energy ray curable pressure-sensitive adhesive has an adhesive force that is reduced by irradiation with energy rays. Therefore, when it is desired to separate the workpiece or workpiece and the pressure-sensitive adhesive sheet 4, it can be easily separated by irradiation with energy rays. it can.

  When the pressure-sensitive adhesive layer 42 is made of an energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer 42 in the protective film-forming composite sheet 3 is preferably cured. Since the material obtained by curing the energy ray-curable pressure-sensitive adhesive usually has a high elastic modulus and high surface smoothness, the protective film-forming film 3 in contact with the cured portion made of the material is cured to protect the film. When the surface is formed, the surface of the protective film that is in contact with the cured portion has high smoothness (gloss) and is excellent in appearance as a protective film for the chip. Further, when laser printing is performed on a protective film having high surface smoothness, the visibility of the printing is improved.

  The energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 42 may be mainly composed of a polymer having energy ray-curability, or a polymer having no energy ray-curability and a lot of energy ray-curable properties. It may be based on a mixture of a functional monomer and / or an oligomer.

  The case where the energy ray curable pressure-sensitive adhesive is mainly composed of a polymer having energy ray curable properties will be described below.

  The polymer having energy ray curability is a (meth) acrylic acid ester (co) polymer (A) (hereinafter referred to as “energy ray”) in which a functional group having energy ray curability (energy ray curable group) is introduced into the side chain. It may be referred to as “curable polymer (A)”). This energy ray curable polymer (A) includes a (meth) acrylic copolymer (a1) having a functional group-containing monomer unit, and an unsaturated group-containing compound (a2) having a substituent bonded to the functional group. It is preferable that it is obtained by making it react.

  The acrylic copolymer (a1) is composed of a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth) acrylic acid ester monomer or a derivative thereof.

  The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) is a monomer having a polymerizable double bond and a functional group such as a hydroxyl group, an amino group, a substituted amino group, or an epoxy group in the molecule. It is preferable that

  More specific examples of the functional group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  Examples of the (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1) include alkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group, cycloalkyl (meth) acrylates, and benzyl (meth) acrylates. Is used. Among these, alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl group are particularly preferable, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) acrylate. 2-ethylhexyl (meth) acrylate or the like is used.

  The acrylic copolymer (a1) usually contains 3 to 100% by mass, preferably 5 to 40% by mass of a structural unit derived from the functional group-containing monomer, and is a (meth) acrylic acid ester monomer or its The structural unit derived from the derivative is usually contained in a proportion of 0 to 97% by mass, preferably 60 to 95% by mass.

  The acrylic copolymer (a1) can be obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylic acid ester monomer or a derivative thereof in a conventional manner. Dimethylacrylamide, vinyl formate, vinyl acetate, styrene and the like may be copolymerized.

  By reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a substituent bonded to the functional group, an energy beam curable polymer (A ) Is obtained.

  The substituent which an unsaturated group containing compound (a2) has can be suitably selected according to the kind of functional group of the functional group containing monomer unit which an acrylic copolymer (a1) has. For example, when the functional group is a hydroxyl group, an amino group or a substituted amino group, the substituent is preferably an isocyanate group or an epoxy group, and when the functional group is an epoxy group, the substituent is an amino group, a carboxyl group or an aziridinyl group. preferable.

  The unsaturated group-containing compound (a2) contains 1 to 5, preferably 1 to 2, energy-polymerizable carbon-carbon double bonds per molecule. Specific examples of such unsaturated group-containing compound (a2) include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1- ( Bisacryloyloxymethyl) ethyl isocyanate; acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound, polyol compound, and hydroxyethyl (meth) Acryloyl monoisocyanate compound obtained by reaction with acrylate; glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1 -Aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl-2-oxazoline and the like.

  The unsaturated group-containing compound (a2) is usually used in a proportion of 10 to 100 equivalents, preferably 20 to 95 equivalents, per 100 equivalents of the functional group-containing monomer of the acrylic copolymer (a1).

  In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), depending on the combination of the functional group and the substituent, the reaction temperature, pressure, solvent, time, presence of catalyst, catalyst Can be selected as appropriate. As a result, the functional group present in the acrylic copolymer (a1) reacts with the substituent in the unsaturated group-containing compound (a2), so that the unsaturated group is contained in the acrylic copolymer (a1). It introduce | transduces into a side chain and an energy-beam curable polymer (A) is obtained.

  The weight average molecular weight of the energy ray curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 to 1,500,000, and more preferably 200,000 to 1,000,000. Is preferred. In addition, the weight average molecular weight (Mw) in this specification is the value of polystyrene conversion measured by the gel permeation chromatography method (GPC method).

  Even when the energy ray-curable pressure-sensitive adhesive is mainly composed of a polymer having energy ray-curability, the energy ray-curable pressure-sensitive adhesive further contains an energy ray-curable monomer and / or oligomer (B). May be.

  As the energy ray-curable monomer and / or oligomer (B), for example, an ester of a polyhydric alcohol and (meth) acrylic acid or the like can be used.

  Examples of the energy ray-curable monomer and / or oligomer (B) include monofunctional acrylic acid esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, penta Erythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol Polyfunctional acrylic acid esters such as di (meth) acrylate and dimethyloltricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo (meth) Acrylate, and the like.

  When the energy ray curable monomer and / or oligomer (B) is blended, the content of the energy ray curable monomer and / or oligomer (B) in the energy ray curable pressure-sensitive adhesive is 5 to 80% by mass. It is preferable that there is especially 20-60 mass%.

  Here, when using ultraviolet rays as an energy ray for curing the energy ray curable resin composition, it is preferable to add a photopolymerization initiator (C), and by using this photopolymerization initiator (C). The polymerization curing time and the amount of light irradiation can be reduced.

  Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4 6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl 1- [4- (1-propenyl) phenyl] propanone}, and 2,2-dimethoxy-1,2-and the like. These may be used alone or in combination of two or more.

  The photopolymerization initiator (C) is energy beam curable copolymer (A) (when energy beam curable monomer and / or oligomer (B) is blended, energy beam curable copolymer (A). And a total amount of 100 parts by mass of the energy ray-curable monomer and / or oligomer (B)) used in an amount in the range of 0.1 to 10 parts by mass, particularly 0.5 to 6 parts by mass. It is preferred that

  In the energy ray curable pressure-sensitive adhesive, other components may be appropriately blended in addition to the above components. Examples of other components include a polymer component or oligomer component (D) that does not have energy beam curability, and a crosslinking agent (E).

  Examples of the polymer component or oligomer component (D) having no energy ray curability include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., and polymers having a weight average molecular weight (Mw) of 3000 to 2.5 million. Or an oligomer is preferable.

  As a crosslinking agent (E), the polyfunctional compound which has the reactivity with the functional group which an energy-beam curable copolymer (A) etc. have can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts. And reactive phenol resins.

  By blending these other components (D) and (E) into the energy ray-curable pressure-sensitive adhesive, tackiness and peelability before curing, strength after curing, adhesion to other layers, storage stability, etc. Can improve. The compounding quantity of these other components is not specifically limited, It determines suitably in the range of 0-40 mass parts with respect to 100 mass parts of energy-beam curable copolymers (A).

  Next, the case where the energy ray-curable adhesive is mainly composed of a mixture of a polymer component not having energy ray curability and an energy ray curable polyfunctional monomer and / or oligomer will be described below.

  As a polymer component which does not have energy-beam sclerosis | hardenability, the component similar to the acrylic copolymer (a1) mentioned above can be used, for example. The content of the polymer component having no energy beam curability in the energy beam curable resin composition is preferably 20 to 99.9% by mass, and more preferably 30 to 80% by mass.

  As the energy ray-curable polyfunctional monomer and / or oligomer, the same one as the above-mentioned component (B) is selected. The blending ratio of the polymer component having no energy beam curability and the energy beam curable polyfunctional monomer and / or oligomer is 10 to 150 parts by mass of the polyfunctional monomer and / or oligomer with respect to 100 parts by mass of the polymer component. It is preferable that it is, and it is especially preferable that it is 25-100 mass parts.

  Also in this case, the photopolymerization initiator (C) and the crosslinking agent (E) can be appropriately blended as described above.

  The thickness of the pressure-sensitive adhesive layer 42 is not particularly limited as long as it can function properly in each step in which the protective film-forming composite sheet 3 is used. Specifically, the thickness is preferably 1 to 50 μm, particularly preferably 2 to 30 μm, and further preferably 3 to 20 μm.

  As an adhesive which comprises the adhesive layer 5 for jig | tool, what has desired adhesive force and removability is preferable, for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive Polyester adhesives, polyvinyl ether adhesives, and the like can be used. Among these, an acrylic pressure-sensitive adhesive that has high adhesion to a jig such as a ring frame and can effectively prevent the protective film-forming composite sheet 3 from being peeled off from the ring frame or the like in a dicing process or the like. preferable. In addition, the base material as a core material may intervene in the middle of the thickness direction of the adhesive layer 5 for jigs.

  On the other hand, the thickness of the pressure-sensitive adhesive layer 5 for jigs is preferably 5 to 200 μm, and particularly preferably 10 to 100 μm, from the viewpoint of adhesion to a jig such as a ring frame.

2. Method for Producing Composite Film for Forming Protective Film Preferably, the composite sheet 3 for forming a protective film is prepared separately from a first laminate including the protective film-forming film 1 and a second laminate including the adhesive sheet 4. Then, it can be manufactured by laminating the protective film-forming film 1 and the pressure-sensitive adhesive sheet 4 using the first laminated body and the second laminated body, but is not limited thereto.

  In order to manufacture the first laminate, the protective film-forming film 1 is formed on the release surface of the first release sheet. Specifically, a coating agent for a protective film-forming film containing a curable adhesive constituting the protective film-forming film 1 and, if desired, further a solvent is prepared, and a roll coater, a knife coater, a roll knife coater, an air knife The protective film-forming film 1 is formed by applying to the release surface of the first release sheet with a coating machine such as a coater, die coater, bar coater, gravure coater, curtain coater, and drying. Next, a laminate (first laminate) in which the release surface of the second release sheet is superimposed on the exposed surface of the protective film-forming film 1 and pressure-bonded, and the protective film-forming film 1 is sandwiched between the two release sheets. )

  In this 1st laminated body, a half cut may be given if desired, and the protective film formation film 1 (and 2nd peeling sheet) may be made into a desired shape, for example, a circular shape. In this case, what is necessary is just to remove suitably the protective film formation film 1 and the excess part of the 2nd peeling sheet which arose by the half cut.

  On the other hand, in order to produce the second laminate, a coating agent for the pressure-sensitive adhesive layer further containing a pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 42 and, if desired, a solvent, on the release surface of the third release sheet. The pressure-sensitive adhesive layer 42 is formed by applying and drying. Then, the base material 41 is crimped | bonded to the exposed surface of the adhesive layer 42, and the laminated body (2nd laminated body) which consists of the adhesive sheet 4 which consists of the base material 41 and the adhesive layer 42, and a 3rd peeling sheet. obtain.

  Here, when the pressure-sensitive adhesive layer 42 is made of an energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer 42 may be irradiated with energy rays at this stage to cure the pressure-sensitive adhesive layer 42 or to protect it. The adhesive layer 42 may be cured after being laminated with the film forming film 1. When the pressure-sensitive adhesive layer 42 is cured after being laminated with the protective film forming film 1, the pressure-sensitive adhesive layer 42 may be cured before the dicing process, or the pressure-sensitive adhesive layer 42 may be cured after the dicing process.

  As energy rays, ultraviolet rays, electron beams, etc. are usually used. The irradiation amount of energy rays varies depending on the type of energy rays. For example, in the case of ultraviolet rays, the amount of light is preferably 50 to 1000 mJ / cm 2, particularly preferably 100 to 500 mJ / cm 2. In the case of an electron beam, about 10 to 1000 krad is preferable.

  When the first laminate and the second laminate are obtained as described above, the second release sheet in the first laminate is released and the third release sheet in the second laminate is released. Then, the protective film forming film 1 exposed in the first laminate and the adhesive layer 42 of the adhesive sheet 4 exposed in the second laminate are overlapped and pressure-bonded. The pressure-sensitive adhesive sheet 4 may be half-cut as desired to have a desired shape, for example, a circular shape having a larger diameter than the protective film-forming film 1. In this case, an excess portion of the pressure-sensitive adhesive sheet 4 generated by the half cut may be removed as appropriate.

  Thus, the pressure-sensitive adhesive sheet 4 in which the pressure-sensitive adhesive layer 42 is laminated on the base material 41, the protective film-forming film 1 laminated on the pressure-sensitive adhesive layer 42 side of the pressure-sensitive adhesive sheet 4, and the protective film-forming film 1 The composite sheet 3 for protective film formation which consists of the 1st peeling sheet laminated | stacked on the opposite side to the adhesive sheet 4 in is obtained. Finally, after peeling off the first release sheet, a jig adhesive layer 5 is formed on the peripheral edge of the protective film forming film 1 opposite to the adhesive sheet 4. The jig pressure-sensitive adhesive layer 5 can also be applied and formed in the same manner as the pressure-sensitive adhesive layer 42.

3. Method for Using Protective Film Forming Composite Sheet A method for producing a chip with a protective film from a semiconductor wafer as a workpiece by using the protective film forming composite sheet 3 according to this embodiment will be described below.

  As shown in FIG. 4, the protective film forming film 1 is attached to the semiconductor wafer 6, and the jig adhesive layer 5 is attached to the ring frame 7. When the protective film forming film 1 is stuck to the semiconductor wafer 6, the protective film forming film 1 may be heated to exhibit adhesiveness if desired.

  Thereafter, the protective film forming film 1 is cured to form a protective film, and a semiconductor wafer 6 with a protective film is obtained. When the protective film forming film 1 is a thermosetting adhesive, the protective film forming film 1 may be heated at a predetermined temperature for an appropriate time. In addition, you may perform hardening of the protective film formation film 1 after a dicing process.

  If the semiconductor wafer 6 with a protective film is obtained as mentioned above, laser printing will be performed by irradiating the protective film with a laser beam through the adhesive sheet 4 if desired. In addition, you may perform this laser printing before hardening of the protective film formation film 1. FIG.

  Subsequently, the semiconductor wafer 6 with a protective film is diced according to a conventional method to obtain a chip having a protective film (chip with a protective film). Thereafter, the pressure-sensitive adhesive sheet 4 is expanded in a plane direction as desired, and a chip with a protective film is picked up from the pressure-sensitive adhesive sheet 4.

  The chip with a protective film obtained as described above is excellent in appearance because grinding marks by back grinding are hidden by the protective film and cannot be visually observed. Moreover, since the chip | tip with a protective film and the semiconductor wafer with a protective film can perform an infrared test through a protective film, a crack etc. can be discovered by an infrared test and a product yield can be improved.

4). Another Embodiment of Composite Sheet for Protective Film Formation FIG. 3 is a cross-sectional view of a composite sheet for protective film formation according to another embodiment of the present invention. As shown in FIG. 3, the protective sheet-forming composite sheet 3 </ b> A according to this embodiment includes a pressure-sensitive adhesive sheet 4 in which a pressure-sensitive adhesive layer 42 is laminated on one surface of a substrate 41, and a pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet 4. And a protective film forming film 1 laminated on the 42 side. The protective film forming film 1 in the embodiment is formed to be substantially the same as or slightly larger than the work in the surface direction, and smaller than the pressure-sensitive adhesive sheet 4 in the surface direction. The part of the pressure-sensitive adhesive layer 42 where the protective film forming film 1 is not laminated can be attached to a jig such as a ring frame.

  The material and thickness of each member of the protective film-forming composite sheet 3A according to the present embodiment are the same as the material and thickness of each member of the protective film-forming composite sheet 3 described above. However, when the pressure-sensitive adhesive layer 42 is made of an energy ray-curable pressure-sensitive adhesive, the portion in contact with the protective film forming film 1 in the pressure-sensitive adhesive layer 42 cures the energy ray-curable pressure-sensitive adhesive, and the other portions are energy. It is preferable not to cure the linear curable adhesive. Thereby, while being able to make high the smoothness (gloss) of the protective film which hardened the protective film formation film 1, the adhesive force with respect to jigs, such as a ring frame, can be maintained highly.

  The jig adhesive layer 5 of the protective film-forming composite sheet 3 described above and the peripheral edge of the adhesive layer 42 of the adhesive sheet 4 of the protective film-forming composite sheet 3A on the side opposite to the substrate 41 are provided. A similar adhesive layer for jigs may be provided separately.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, a release sheet may be laminated on the side opposite to the adhesive sheet 4 in the protective film forming film 1 of the protective film forming composite sheets 3 and 3A.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
The following components were mixed at a blending ratio (in terms of solid content) shown in Table 1, and diluted with methyl ethyl ketone so that the solid content concentration was 61% by mass to prepare a coating agent for a protective film-forming film.
(A) Binder polymer: (meth) acrylic acid ester copolymer obtained by copolymerizing 10 parts by mass of n-butyl acrylate, 70 parts by mass of methyl acrylate, 5 parts by mass of glycidyl methacrylate and 15 parts by mass of 2-hydroxyethyl acrylate ( (Weight average molecular weight: 800,000, glass transition temperature: -1 ° C)
(B-1) Bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, jER828, epoxy equivalent of 184 to 194 g / eq)
(B-2) Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER1055, epoxy equivalent 800 to 900 g / eq)
(B-3) Dicyclopentadiene type epoxy resin (Dainippon Ink & Chemicals, Epiklone HP-7200HH, epoxy equivalent 255-260 g / eq)
(C) Thermally active latent epoxy resin curing agent: Dicyandiamide (manufactured by ADEKA, Adeka Hardener EH-3636AS, amount of active hydrogen 21 g / eq)
(D) Curing accelerator: 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd., Curesol 2PHZ)
(E-1) Silica filler (manufactured by Admatechs, SC2050MA, average particle size 0.5 μm)
(E-2) Silica filler (manufactured by Tokuyama, UF310, average particle size 3 μm)
(E-3) Silica filler (manufactured by Tatsumori, SV-10, average particle size 8 μm)
(F) Colorant: Carbon black (Mitsubishi Chemical Corporation, # MA650, average particle size 28 nm)
(G) Silane coupling agent (Nihon Unicar, A-1110)

  A first release sheet (manufactured by Lintec: SP-PET3811, thickness 38 μm) having a silicone release agent layer formed on one side of a polyethylene terephthalate (PET) film, and a silicone release agent on one side of the PET film A second release sheet (made by Lintec Corporation: SP-PET 381031, thickness 38 μm) formed with a layer was prepared.

  On the release surface of the first release sheet, the coating agent for a protective film-forming film is applied with a knife coater so that the final protective film-forming film has a thickness of 25 μm. And dried at 120 ° C. for 2 minutes to form a protective film-forming film. Next, the release surface of the second release sheet is laminated on the protective film-forming film and bonded together, and the first release sheet (release sheet 21 in FIG. 1) and the protective film-forming film (protective film-forming film in FIG. 1). 1) A protective film-forming sheet composed of (thickness: 25 μm) and a second release sheet was obtained.

[Examples 2 to 4, Comparative Examples 1 to 4]
A protective film-forming sheet was produced in the same manner as in Example 1 except that the types and blending amounts of the components constituting the protective film-forming film were changed as shown in Table 1.

[Test Example 1] <Measurement of light transmittance>
The second release sheet is peeled from the protective film-forming sheets obtained in the examples and comparative examples, and heated in an oven at 130 ° C. for 2 hours in an oven to thermally cure and protect the protective film-forming film. A membrane was obtained. Thereafter, the first release sheet was peeled off.

  The transmittance of the protective film was measured using a spectrophotometer (manufactured by SHIMADZU, UV-VIS-NIR SPECTROTOPOMETER UV-3600). ) Was extracted. For the measurement, the attached large sample chamber MPC-3100 was used, and the measurement was performed without using the built-in integrating sphere. The results are shown in Table 1.

[Test Example 2] <Evaluation of grinding mark concealment>
The 2nd peeling sheet was peeled from the sheet | seat for protective film formation obtained in the Example and the comparative example, and the film for protective film formation was exposed. While the # 2000 polished silicon wafer (diameter: 200 mm, thickness: 350 μm) is heated to 70 ° C. using a tape mounter (Adwill RAD-3600 F / 12, manufactured by Lintec Corporation) Then, the first release sheet was peeled off. Then, it heated at 130 degreeC for 2 hours, the film for protective film formation was hardened, and it was set as the protective film, and the silicon wafer with a protective film was obtained.

  The obtained 10 silicon wafers with protective film were visually observed to confirm whether grinding marks on the polished surface of the silicon wafer could be seen through the protective film. In all the silicon wafers with a protective film, those with no grinding marks visible were evaluated as good grinding mark concealability (A), and those with even one grinding mark visible were evaluated as poor grinding mark concealability (B). The results are shown in Table 1.

[Test Example 3] <Evaluation of suitability for infrared inspection>
A dicing tape (manufactured by Lintec Corporation, Adwill D-175) was attached to the protective film surface side of the silicon wafer with a protective film obtained in Test Example 2. Then, the silicon wafer with a protective film was diced into a size of 3 mm × 3 mm and picked up to obtain a silicon chip with a protective film. The protective film side of the obtained silicon chip with a protective film is observed with an infrared microscope (Olympus, BX-IR) to confirm whether the silicon chip grinding marks and chipping can be observed through the protective film. The suitability of infrared inspection was evaluated. The results are shown in Table 1.
A: Grinding marks could be clearly observed. Further, chipping with a distance of 5 μm or more and less than 10 μm from the chip side surface could be clearly observed.
B: Grinding marks could be clearly observed. Further, chipping with a distance of 10 μm or more from the chip side face could be clearly observed, but chipping with a distance from the chip side face of 5 μm or more to less than 10 μm was somewhat unclear.
C: Grinding marks were observed to some extent. Further, chipping with a distance of 5 μm or more and less than 10 μm from the side surface of the chip could not be observed, and chipping with a distance of 10 μm or more from the side surface of the chip was somewhat unclear.
D: Grinding marks could not be observed and chipping could not be observed regardless of size.

  As can be seen from Table 1, the protective film-forming film of the example in which the light transmittance at a wavelength of 550 nm is 20% or less and the light transmittance at a wavelength of 1600 nm is 25% or more is suitable for concealing grinding marks and suitability for infrared inspection. Both were excellent.

  The protective film-forming film and the protective film-forming (composite) sheet according to the present invention are suitably used for manufacturing a chip having a protective film from a semiconductor wafer. The inspection method according to the present invention is suitable for inspecting cracks and the like in a chip having a protective film.

DESCRIPTION OF SYMBOLS 1 ... Protective film formation film 2 ... Protective film formation sheet 21 ... Release sheet 3,3A ... Composite film 4 for protective film formation ... Adhesive sheet 41 ... Base material 42 ... Adhesive layer 5 ... Adhesive layer 6 for jigs ... Semiconductor wafer 7 ... Ring frame

The present invention relates to a protective film-forming film and a protective film-forming (composite) sheet that can form a protective film on a workpiece such as a semiconductor wafer or a workpiece (for example, a semiconductor chip) obtained by processing the workpiece, and the like The present invention relates to an inspection method for inspecting a workpiece or a workpiece with a protective film obtained by using the above. The present invention also relates to a laser printing method using the composite sheet for forming a protective film.

The present invention has been made in view of the actual situation as described above, and is capable of inspecting a crack or the like existing in a workpiece or a workpiece obtained by processing the workpiece, and is present in the workpiece or the workpiece. Inspection of protective film-forming film and protective film-forming (composite) sheet capable of forming a protective film in which grinding marks are not visible by visual inspection, and a workpiece or a workpiece with a protective film obtained by using them The purpose is to provide an inspection method. In the present invention, the surface of the protective film that is in contact with the cured portion has a high smoothness (gloss), and is excellent in appearance as a protective film for the chip. Also, the protective film has a high surface smoothness. It is an object of the present invention to provide a laser printing method in which when laser printing is performed, the visibility of the printing is improved.

3rdly, this invention is a protective film provided with the adhesive sheet by which an adhesive layer is laminated | stacked on the one surface side of a base material, and the protective film formation film laminated | stacked on the said adhesive layer side of the said adhesive sheet A composite sheet for forming, wherein the pressure-sensitive adhesive layer is composed of an energy ray-curable pressure-sensitive adhesive, the light transmittance of the protective film-forming film at a wavelength of 1600 nm is 25% or more, and the wavelength of the protective film-forming film is 550 nm. The composite film for forming a protective film is provided (Invention 5).

According to the above inventions (Inventions 4 and 5), it is possible to inspect by infrared rays such as cracks existing in a workpiece or a workpiece obtained by processing the workpiece, and grinding marks existing in the workpiece or workpiece are visually observed. A protective film that cannot be seen can be formed. Moreover, according to the said invention (invention 5), the surface which is contacting the said hardening part of a protective film becomes high smoothness (gloss), and becomes what was excellent in aesthetics as a protective film of a chip | tip, and surface When laser printing is performed on a protective film having high smoothness, the visibility of the printing can be improved.

The present invention to a 6, based on the test method (invention 8, 9), provides a workpiece is determined to be nondefective (invention 11).
Furthermore, this invention sticks the protective film formation film of the composite sheet for protective film formation as described in any one of Claims 1-4 to the back surface of the semiconductor wafer by which the circuit was formed in the surface and it was back-grinded. A step of reducing the adhesive strength of the energy ray-curable adhesive of the pressure-sensitive adhesive layer by energy ray irradiation, a step of curing the protective film-forming film to form a protective film, and the protective film. A process of irradiating a laser beam and performing laser printing;
When the laser beam is irradiated onto the protective film, the pressure-sensitive adhesive layer in the protective film-forming composite sheet is cured.

According to the protective film-forming film and protective film-forming (composite) sheet according to the present invention, inspection by infrared rays such as cracks existing in a workpiece or a workpiece obtained by processing the workpiece is possible, and the workpiece or It is possible to form a protective film in which grinding marks existing on the workpiece are not visible by visual inspection. Further, according to the inspection method of the present invention, it is possible to inspect a crack or the like existing in a workpiece or a workpiece by using infrared rays. In addition, according to the composite sheet for forming a protective film and the laser printing method according to the present invention, the surface of the protective film that is in contact with the cured portion has high smoothness (gross), and is beautiful as a protective film for the chip. When laser printing is performed on a protective film having excellent surface smoothness, the visibility of the printing is improved.

Claims (13)

The light transmittance at a wavelength of 1600 nm is 25% or more and 90% or less,
A protective film-forming film having a light transmittance of 20% or less at a wavelength of 550 nm.   The said protective film formation film is a single layer comprised from an uncured curable adhesive, The protective film formation film of Claim 1 characterized by the above-mentioned.   The protective film forming film according to claim 2, wherein the curable adhesive contains a colorant and a filler having an average particle diameter of 0.01 to 3 μm.   The protective film formation film as described in any one of Claims 1-3 with which 0.05-0.75 mass% coloring agent is mix | blended. The protective film forming film according to any one of claims 1 to 4,
A protective film forming sheet comprising: a release sheet laminated on one or both surfaces of the protective film forming film. A pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on one side of the substrate;
A protective film-forming composite sheet comprising a protective film-forming film laminated on the pressure-sensitive adhesive layer side of the pressure-sensitive adhesive sheet,
The light transmittance at a wavelength of 1600 nm of the protective film-forming film is 25% or more and 90% or less,
The protective film-forming composite sheet, wherein the protective film-forming film has a light transmittance of 10% or less at a wavelength of 550 nm.   The composite sheet for forming a protective film according to claim 6, wherein the protective film-forming film is a single layer composed of an uncured curable adhesive.   The composite sheet for forming a protective film according to claim 7, wherein the curable adhesive contains a colorant and a filler having an average particle size of 0.01 to 3 μm.   The composite film for protective film formation as described in any one of Claims 6-8 in which 0.05-0.75 mass% coloring agent is mix | blended with the protective film formation film. The protective film forming film according to any one of claims 1 to 4, the protective film forming sheet according to claim 5, or the protective film forming composite sheet according to any one of claims 6 to 9. By using it to form a protective film on the work, manufacture a work with a protective film,
An inspection method for inspecting a workpiece with a protective film or a workpiece obtained by processing the workpiece with a protective film using infrared rays through the protective film.   The inspection method according to claim 10, wherein the workpiece is a semiconductor wafer and the workpiece is a semiconductor chip.   A workpiece with a protective film, which is determined to be a non-defective product based on the inspection method according to claim 10 or 11.   A workpiece determined to be a non-defective product based on the inspection method according to claim 10 or 11.

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