Adhesive film and production method of semiconductor device

Abstract

To provide: an adhesive film capable of suppressing an adhesive residue on an adherend while retaining adhesive strength even when being extended; and a production method of a semiconductor device using the adhesive film.SOLUTION: An adhesive film includes an adhesive layer comprising two or more polymers and a base material layer, and satisfies (1) or (2). (1) A ratio S' / S of a value S' which is an arithmetical average height (Sa) of a surface of the adhesive layer when the adhesive film is extended by 200% and a value S which is an arithmetical average height (Sa) of a surface of the adhesive layer before extension of the adhesive film is 9.5 or less. (2) In the at least two or more polymers, the difference of SP value is 0.3 or less and the hydroxyl value ratio is 40 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing an adhesive film and a semiconductor device. [Background technology]

[0002] In a manufacturing method for electronic components such as semiconductor chips and ceramic capacitors, a wafer placed on a stretchable film is diced into pieces of the desired size, and then the film is stretched to increase the distance between the semiconductor chips, and the semiconductor chips are picked up (see, for example, Patent Document 1).

[0003] In recent years, the processing technologies for electronic components have become more diverse, and technologies for processing individual semiconductor chips on a stretched film are being considered. When processing the semiconductor chips, there is a demand for improving the adhesive strength of the film during stretching so that the semiconductor chips do not come off or become misaligned from the stretched film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-63676 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the adhesive layer is made more adhesive to maintain the adhesive strength of the film when stretched, a part of the adhesive layer moves to the adherend such as a chip, causing so-called adhesive residue on the adherend. Thus, there is a trade-off between adhesive strength when stretched and suppression of adhesive residue on the adherend, and it is difficult to achieve both.

[0006] In view of the above situation, an object of one embodiment of the present disclosure is to provide an adhesive film that can retain its adhesive strength even when stretched while suppressing adhesive residue on an adherend, and a method for manufacturing a semiconductor device using this adhesive film. [Means for solving the problem]

[0007] Specific means for achieving the above object include the following aspects. <1> An adhesive film comprising an adhesive layer containing two or more types of polymers and a base layer, An adhesive film, in which the ratio S' / S of the arithmetic mean height (Sa) of the surface of the adhesive layer when the adhesive film is stretched 200% to the arithmetic mean height (Sa) of the surface of the adhesive layer of the adhesive film before stretching is 9.5 or less. <2> At least two of the polymers have a difference in SP value of 0.3 or less. <1> The adhesive film according to claim 1. <3> At least two of the polymers have a hydroxyl value ratio of 40 or less. <1> The adhesive film according to claim 1. <4> The adhesive layer includes two or more polymers, and a base layer. At least two of the polymers have a difference in SP value of 0.3 or less and a hydroxyl value ratio of 40 or less. <5> The arithmetic mean height (Sa) value S of the surface of the adhesive layer before elongation is 0.001 μm to 5.000 μm; <1> ~ <4> 13. The adhesive film according to claim 12 . <6> The content of the polymer having the highest content in the adhesive layer is 85% by mass or less with respect to the total content of the polymers contained in the adhesive layer. <1> ~ <5> 13. The adhesive film according to claim 12 . <7> A plurality of semiconductor chips are arranged on one surface. <1> ~ <6> 2. A method for manufacturing a semiconductor device, comprising: expanding the space between two adjacent semiconductor chips by stretching the adhesive film described in any one of claims 1 to 11. <8> After the stretching, peeling the semiconductor chip from the adhesive film. <7> A method for manufacturing the semiconductor device according to claim 1. <9> processing the semiconductor chip after the elongation and before peeling the semiconductor chip; <8> A method for manufacturing the semiconductor device according to claim 1. <10> The processing includes providing a functional layer on the semiconductor chip. <9> A method for manufacturing the semiconductor device according to claim 1. Effect of the Invention

[0008] According to one aspect of the present disclosure, there is provided an adhesive film that can retain its adhesive strength even when stretched and can reduce adhesive residue on an adherend, and a method for manufacturing a semiconductor device using this adhesive film. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic cross-sectional view showing the configuration of an adhesive film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified. The same applies to the numerical values ​​and their ranges, and do not limit the present disclosure.

[0011] In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved. In the present disclosure, a numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.

[0012] In the present disclosure, each component may contain multiple types of corresponding substances. When multiple types of substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In this disclosure, the term "layer" includes cases where the layer is formed over the entire area when the area in which the layer exists is observed, as well as cases where the layer is formed over only a portion of the area.

[0013] In the present disclosure, the thickness of the adhesive film or each layer constituting the adhesive film can be measured by a known method. For example, it may be measured using a dial gauge or the like, or it may be measured from a cross-sectional image of the adhesive film. Alternatively, the material constituting the layer may be removed using a solvent or the like, and the thickness may be calculated from the mass before and after removal, the density of the material, the area of ​​the layer, etc. If the thickness of the layer is not constant, the arithmetic average value of the values ​​measured at any five points is taken as the thickness of the layer.

[0014] In the present disclosure, "(meth)acrylic" means either or both of acrylic and methacrylic, and "(meth)acrylate" means either or both of acrylate and methacrylate. In the present disclosure, when an embodiment is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

[0015] <Adhesive film> The pressure-sensitive adhesive film in one embodiment of the present disclosure includes a pressure-sensitive adhesive layer containing two or more types of polymers and a base layer, and satisfies the following (1) or (2). (1) The ratio S' / S of the arithmetic mean height (Sa) of the surface of the adhesive layer when the adhesive film is stretched by 200% to the arithmetic mean height (Sa) of the surface of the adhesive layer of the adhesive film before stretching is 9.5 or less. (2) At least two of the polymers have a difference in SP value of 0.3 or less and a hydroxyl value ratio of 40 or less.

[0016] The pressure-sensitive adhesive film of the present disclosure having the above configuration can maintain its adhesive strength even when stretched, while suppressing adhesive residue on the adherend. When the adhesive layer contains only one type of polymer, for example, if a polymer that improves adhesion is used, the adhesive strength can be increased, and if a polymer that improves peelability is used, it is possible to suppress adhesive residue on the adherend when the adherend is peeled off. However, it is difficult to achieve both of these in an adhesive layer that contains only one type of polymer. In the adhesive film of the present disclosure, two or more types of polymers are contained in the adhesive layer, thereby achieving both high adhesive strength and suppression of adhesive residue when the adherend is peeled off. In particular, by making the ratio S' / S of the arithmetic mean height (Sa) value S of the surface of the adhesive layer when the adhesive film is stretched by 200% to the arithmetic mean height (Sa) value S of the surface of the adhesive layer of the adhesive film before stretching 9.5 or less, the surface unevenness of the adhesive film when stretched is appropriately suppressed, and the adhesive strength is effectively maintained even when the adhesive film is stretched.

[0017] In addition, by incorporating at least two types of polymers with a difference in SP value of 0.3 or less in the adhesive layer, the occurrence of a microphase separation structure of the polymer in the adhesive layer can be appropriately suppressed. This makes it possible to appropriately suppress the occurrence of unevenness on the surface of the adhesive film due to the microphase separation structure when the adhesive film is stretched, and the adhesive strength is maintained even when stretched. In addition, by incorporating at least two polymers having a hydroxyl value ratio of 40 or less in the adhesive layer, these polymers are appropriately compatible with each other, and therefore the occurrence of a microphase separation structure can be appropriately suppressed. When the hydroxyl value ratio is 40 or less, the polymers having a large hydroxyl value and the polymers having a small hydroxyl value are prevented from separately aggregating with each other, and the occurrence of a microphase separation structure can be appropriately suppressed.

[0018] As an example of the adhesive film of the present disclosure, a cross-sectional configuration of the adhesive film is shown generally in Fig. 1. As shown in Fig. 1, the adhesive film 30 includes a base layer 10 and an adhesive layer 20. The adhesive film 30 may include other layers.

[0019] [Adhesive layer] The adhesive layer contains two or more polymers. In a preferred embodiment, the difference in SP value between the at least two polymers is 0.3 or less, and the hydroxyl value ratio is 40 or less.

[0020] When the difference in SP value between at least two types of polymers is 0.3 or less, these polymers are highly compatible with each other, and therefore a phase separation structure tends not to form in the adhesive layer. When an adhesive layer having many or large phase separation structures is stretched, the amount of stretching of the adhesive layer becomes partially non-uniform, and unevenness is likely to appear on the surface of the adhesive layer.

[0021] At least two kinds of polymers contained in the adhesive layer preferably have a difference in SP value of 0.2 or less, more preferably 0.1 or less. The lower limit of the difference in SP value is not particularly limited. In the present disclosure, the SP value is a value obtained by the Fedors method.

[0022] Furthermore, when the hydroxyl value ratio of the at least two types of polymers is 40 or less, aggregation of the respective polymers is suppressed, and a phase-separated structure tends not to form in the adhesive layer.

[0023] The at least two types of polymers contained in the adhesive layer preferably have a hydroxyl value ratio of 30 or less, more preferably 15 or less. Furthermore, the at least two types of polymers contained in the adhesive layer preferably have a hydroxyl value ratio of 1.5 or more, more preferably 2.0 or more, and even more preferably 3.0 or more.

[0024] Polymers with a large hydroxyl value tend to become hard when crosslinked, while polymers with a small hydroxyl value tend not to become hard when crosslinked. From the viewpoint of the adhesive film exhibiting excellent adhesiveness, it is desirable for the adhesive film to be flexible, but the trade-off is that adhesive residue tends to be easily generated due to cohesive failure when peeled off. If the hydroxyl value ratio of at least two types of polymers contained in the adhesive layer is 1.5 or more, a hard polymer can be interposed between the flexible polymers, and adhesive residue due to cohesive failure can be effectively suppressed.

[0025] The hydroxyl value ratio in this disclosure is a value calculated by using the hydroxyl value of the polymer with the smaller hydroxyl value as the denominator and the hydroxyl value of the polymer with the larger hydroxyl value as the numerator. The hydroxyl value is the number of milligrams of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl group when 1 g of a sample is acetylated, and is calculated using the following formula.

[0026]

number

[0027] The type of polymer is not particularly limited, and is preferably selected in consideration of the adhesiveness, heat resistance, etc. of the adhesive layer. Specific examples of the polymer include (meth)acrylic polymer, silicone, urethane polymer, etc. At least one type of polymer is preferably a (meth)acrylic polymer, and more preferably two or more types of (meth)acrylic polymers are used.

[0028] The (meth)acrylic polymer may be a homopolymer or a copolymer, or a homopolymer and a copolymer may be used in combination. At least one of the (meth)acrylic polymers is preferably a copolymer.

[0029] The copolymer preferably contains a structural unit derived from a monomer having a relatively low glass transition temperature (Tg) (for example, -20°C or lower). A monomer having a relatively low Tg refers to a monomer having a glass transition temperature of 20°C or lower when a homopolymer is synthesized from the monomer. Examples of monomer A having a Tg of 20°C or lower include butyl (meth)acrylate, ethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The copolymer may contain one type of structural unit derived from monomer A alone, or two or more types in combination.

[0030] When the copolymer contains a structural unit derived from monomer A, the total content of the structural units derived from monomer A in the copolymer is preferably more than 60% by mass, more preferably 70% by mass or more, and even more preferably 75% by mass or more. Moreover, the total content is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 88.5% by mass or less.

[0031] At least one polymer may be a copolymer containing a structural unit derived from a monomer B having a functional group. Examples of the functional group include a carboxylic acid group, a hydroxyl group, an amide group, and a nitrile group. The functional group may be a crosslinkable functional group or a non-crosslinkable functional group. Examples of the crosslinkable functional group include a carboxylic acid group, a hydroxyl group, and an amide group, and examples of the non-crosslinkable functional group include a nitrile group. The copolymer may contain one type of structural unit derived from monomer B alone or in combination of two or more types.

[0032] The copolymer containing a structural unit derived from the monomer B having a functional group may be a crosslinked polymer. The crosslinked polymer can be crosslinked using a crosslinking agent. The crosslinked polymer is preferably a crosslinked (meth)acrylic polymer, and more preferably a crosslinked (meth)acrylic copolymer.

[0033] Examples of the monomer B1 having a crosslinkable functional group include (meth)acrylic acid, hydroxyethyl (meth)acrylate, and (meth)acrylamide. Examples of the monomer B2 having a non-crosslinkable functional group include (meth)acrylonitrile.

[0034] When the copolymer contains a structural unit derived from monomer B1, the total content of the structural units derived from monomer B1 in the copolymer is preferably 0.5% by mass or more, more preferably 4.0% by mass or more, and even more preferably 10% by mass or more. The total content is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0035] When the copolymer contains a structural unit derived from monomer B2, the total content of the structural units derived from monomer B2 in the copolymer is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. Also, the content is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0036] The copolymer may contain structural units derived from other monomers other than the monomer A and the monomer B. Examples of the other monomers include monomers having a Tg of more than 20° C., such as 1-adamantyl acrylate and 1-adamantyl methacrylate. The total content of structural units derived from other monomers in the copolymer is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0037] From the viewpoint of suppressing adhesive residue on the adherend, the weight average molecular weight (Mw) of the polymer is, for example, 1×10 5 may be greater than or equal to 3 x 10 5 From the viewpoint of ensuring adhesiveness, Mw is 1.1×10 6 may be less than or equal to 1 x 10 6 It may be the following: From the viewpoint of suppressing adhesive residue on the adherend, the number average molecular weight (Mn) of the polymer is 10 × 10 4 It can be 12 x 10 or more. 4 From the viewpoint of ensuring adhesiveness, Mn is 20×10 4 may be less than or equal to 15 x 10 4 It may be the following: The Mn and Mw of a polymer are measured by a conventional method using GPC (gel permeation chromatography).

[0038] The content of the polymer with the highest content in the adhesive layer is preferably 85% by mass or less, more preferably 83% by mass or less, and even more preferably 78% by mass or less, based on the total content of the polymers contained in the adhesive layer. When the content of the polymer with the highest content is 85% by mass or less, the occurrence of adhesive residue when the semiconductor chip is peeled off tends to be further suppressed.

[0039] When the polymer contains a crosslinked polymer, the adhesive layer preferably contains a crosslinking agent. In the present disclosure, a state in which a part or all of the crosslinking agent contained in the adhesive layer forms a crosslinked structure is also referred to as a "state in which the adhesive layer contains a crosslinking agent." The type of crosslinking agent is not particularly limited and can be selected depending on the type of adhesive, etc. Specific examples include isocyanate crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, etc. Among the above crosslinking agents, isocyanate crosslinking agents are preferred from the viewpoint of stable adhesive properties. The crosslinking agents contained in the adhesive layer may be one type alone or a combination of two or more types.

[0040] The isocyanate crosslinking agent is not particularly limited and can be selected from known compounds having an isocyanate group (isocyanate compounds). From the viewpoint of reactivity, bifunctional isocyanate compounds (compounds having two isocyanate groups) and polyfunctional isocyanates (compounds having three or more isocyanate groups) are preferred, and polyfunctional isocyanate compounds are more preferred.

[0041] Examples of the bifunctional isocyanate compound include aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, aromatic diisocyanate compounds, carbodiimide-modified products of these diisocyanate compounds, and polymer compounds having these diisocyanate compounds in the molecule.

[0042] Examples of the aliphatic diisocyanate compound include 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), and lysine diisocyanate.

[0043] Examples of the alicyclic diisocyanate compound include norbornane diisocyanate methyl (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), and H12-MDI (hydrogenated MDI).

[0044] Examples of aromatic diisocyanate compounds include dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylidene diisocyanate (TMXDI), tolidine diisocyanate (TODI), and 1,5-naphthalene diisocyanate (NDI).

[0045] Examples of the polyfunctional isocyanate compound include a trimer of a bifunctional isocyanate compound and a polymer compound having a trimer of a bifunctional isocyanate compound in the molecule. Examples of the trimer of a difunctional isocyanate compound include an isocyanurate of a difunctional isocyanate compound, an adduct of a difunctional isocyanate compound, and a biuret of a difunctional isocyanate compound.

[0046] Among isocyanate crosslinking agents, a trimer of an aliphatic diisocyanate compound is preferred, an adduct of an aliphatic diisocyanate compound is more preferred, an adduct of 1,6-hexamethylene diisocyanate is even more preferred, and an adduct of 1,6-hexamethylene diisocyanate with trimethylolpropane (TMP) is particularly preferred.

[0047] The content of the crosslinking agent in the adhesive layer may be, for example, 0.1 parts by mass to 10 parts by mass, 0.5 parts by mass to 5 parts by mass, or 1 part by mass to 3 parts by mass per 100 parts by mass of the total blend amount of the polymers in the adhesive layer.

[0048] If necessary, the adhesive layer may contain a plasticizer. The type of plasticizer is not particularly limited and can be selected according to the type of adhesive, etc. Specific examples include polyester plasticizers such as polyester adipate, phthalates such as bis(2-ethylhexyl) phthalate, terephthalates such as bis(2-ethylhexyl) terephthalate, adipic acids such as bis(2-ethylhexyl) adipate, trimellitic acid esters, phosphoric acid esters, citrate esters, and epoxidized vegetable oils. The plasticizer contained in the adhesive layer may be one type alone or a combination of two or more types.

[0049] The molecular weight of the polyester plasticizer is not particularly limited and may be within the range of 500 to 4,000, for example. From the viewpoint of suppressing adhesive residue on the adherend, the molecular weight of the polyester plasticizer is preferably 1,500 to 4,000.

[0050] The content of the plasticizer in the adhesive layer may be, for example, 5 parts by mass to 30 parts by mass, 10 parts by mass to 25 parts by mass, or 15 parts by mass to 22 parts by mass per 100 parts by mass of the total blend amount of the polymers in the adhesive layer.

[0051] If necessary, the adhesive layer may contain a tackifier. The type of tackifier is not particularly limited and can be selected according to the type of adhesive, etc. Specific examples include petroleum resins, terpene phenol resins, terpene resins, alicyclic saturated hydrogen resins, β-pinene polymers, hydrogenated rosin, and hydrogenated rosin esters. By including a tackifier in the adhesive layer, the adhesive strength before elongation is improved, and the adhesive retention tends to be more excellent.

[0052] If necessary, the adhesive layer may contain a surfactant, a filler, etc. The content of the filler in the adhesive layer is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the solid content contained in the adhesive layer, from the viewpoint of suppressing a decrease in adhesive strength before elongation. When the adhesive layer contains a filler, the lower limit is not particularly limited, and may be, for example, 1% by mass or more, or 5% by mass or more.

[0053] From the viewpoint of ensuring sufficient adhesive strength to the adherend, the thickness of the adhesive layer is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. From the viewpoint of economy, the thickness of the adhesive layer is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less.

[0054] It is preferable that the polymer component ratio is different between the concave and convex portions of the unevenness appearing on the surface by stretching the PSA film. As an example, it is preferable that the nitrile group content is different between the concave and convex portions, and it is more preferable that the nitrile group content is higher in the convex portions than in the concave portions.

[0055] The component ratio of the polymer in each region and the uneven portion is measured by analyzing the distribution of the components that compose the surface of the adhesive layer using micro-Raman spectroscopy. For example, for the multiple components that compose the adhesive layer, the peaks originating from the components to be analyzed are identified in advance, and the distribution of the components is analyzed by creating a two-dimensional image of the distribution amount of the components based on the signal intensity.

[0056] In the pressure-sensitive adhesive film of the present disclosure, it is also possible to form convex portions where no clear interface is observed. Convex portions where no clear interface is observed refer to those where no particle interface is observed, as in the case of adding a filler, when observed with a laser microscope.

[0057] [Base material layer] The substrate layer is not particularly limited and may be appropriately selected from substrate layers used in the art. From the viewpoint of obtaining good extensibility, the substrate layer preferably contains a resin, more preferably contains a thermoplastic resin. Examples of the thermoplastic resin include polyvinyl chloride, polyester, polyolefin, polyamide, polyimide, polyurethane, thermoplastic elastomer, etc. From the viewpoint of extensibility, polyvinyl chloride is preferred.

[0058] The base layer may contain a plasticizer. When the base layer contains a plasticizer, the content of the plasticizer in the base layer may be, for example, 10 parts by mass to 55 parts by mass, 20 parts by mass to 50 parts by mass, or 25 parts by mass to 45 parts by mass relative to 100 parts by mass of the resin in the adhesive layer.

[0059] From the viewpoint of improving visibility during application, the base layer may contain a colorant. Examples of the colorant include dyes and pigments, and from the viewpoint of durability, pigments are preferred. Specific examples of the colorant include alkali blue, disazo yellow, phthalocyanine blue, Prussian blue, ultramarine blue, and cobalt blue.

[0060] When the colorant is particulate, the maximum particle size of the colorant is preferably smaller than the thickness of the base layer when stretched, from the viewpoint of suppressing the colorant from falling off from the base layer. For example, the maximum particle size of the colorant is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. In the present disclosure, the "maximum particle diameter" of a colorant refers to the maximum value of the maximum diameter of each particle (the length when the diameter of the projected image is the longest) obtained from the projected image of colorant particles (preferably 100 or more particles).

[0061] When the base layer contains a colorant, the content of the colorant in the base layer is, for example, preferably 0.1 mass % to 2.0 mass %, more preferably 0.2 mass % to 1.5 mass %, and even more preferably 0.3 mass % to 1.0 mass %, relative to the total solid content of the base layer.

[0062] From the viewpoint of ensuring sufficient strength, the thickness of the base layer is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 50 μm or more. From the viewpoint of ensuring sufficient extensibility, the thickness of the base layer is preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less.

[0063] [Other configurations] If necessary, a separator or the like may be disposed on the outer surface of the adhesive layer (the surface opposite to the side facing the base layer).

[0064] <Physical properties of adhesive film> In one embodiment of the adhesive film of the present disclosure, the ratio S' / S of the arithmetic mean height (Sa) of the surface of the adhesive layer when the adhesive film is stretched 200% to the arithmetic mean height (Sa) S of the surface of the adhesive layer of the adhesive film before stretching is 9.5 or less.

[0065] In the present disclosure, the adhesive film is stretched by 200% in the following manner. Before stretching the adhesive film, two marks are made on the surface of the adhesive layer, and the film is stretched until the distance between the two marks doubles. When stretching, the two marks are clamped with a jig, and the jig is moved in opposite directions to stretch the adhesive film. The distance between the two marks can be, for example, 10 mm.

[0066] In the present disclosure, the arithmetic mean height (Sa) value S is measured in the following manner. The adhesive film is placed under a laser microscope with the adhesive layer facing up, and images are processed at a magnification of 100x to obtain the arithmetic mean height (Sa) of the adhesive layer surface, which is taken as the value S.

[0067] In the present disclosure, the arithmetic mean height (Sa) value S' is measured in the following manner. After stretching the adhesive film 200% using the method described above, it is attached to a frame plate with a side length of 50 mm, and this frame plate is placed under a laser microscope. Images are processed at a magnification of 100 times to obtain the arithmetic mean height Sa of the surface of the adhesive layer, which is designated as value S'.

[0068] As the laser microscope used to measure the value S and the value S', for example, "Laser Microscope OLS4100" manufactured by Olympus Corporation can be used.

[0069] The ratio S' / S is preferably equal to or less than 8, and more preferably equal to or less than 5. There is no particular lower limit to the ratio S' / S, and it may be equal to or more than 0.5, or may be equal to or more than 1.0.

[0070] From the viewpoint of adhesive strength, the value S of the arithmetic mean height (Sa) is preferably 4.000 μm or less, more preferably 2.000 μm or less, and even more preferably 1.000 μm or less. There is no particular restriction on the lower limit of the value S of the arithmetic mean height (Sa), and it may be 0.001 μm or more, 0.005 μm or more, or 0.010 μm or more.

[0071] From the viewpoint of the retention of the adherend when stretched, the arithmetic mean height (Sa) value S' is preferably 5.000 μm or less, more preferably 2.000 μm or less, and even more preferably 1.000 μm or less. There is no particular restriction on the lower limit of the arithmetic mean height (Sa) value S', and it may be 0.001 μm or more, 0.005 μm or more, or 0.010 μm or more.

[0072] From the viewpoint of the retention of the adherend when stretched, the tack strength (A' value) of the surface of the adhesive layer when the adhesive film is stretched by 200% is preferably 20 gf or more, more preferably 40 gf or more, and even more preferably 60 gf or more. The A' value may be 150 gf or less, 100 gf or less, or 50 gf or less.

[0073] From the viewpoint of adhesive strength, the tack strength (A value) of the surface of the adhesive layer before stretching the adhesive film is preferably 20 gf or more, more preferably 40 gf or more, and even more preferably 60 gf or more. The A value may be 100 gf or less, 80 gf or less, or 40 gf or less.

[0074] From the viewpoint of suppressing adhesive residue on an adherend while retaining adhesive strength even when stretched, the ratio A' / A in the adhesive film is preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 1.0 or more. The ratio A' / A in the pressure-sensitive adhesive film is preferably 7.0 or less, more preferably 5.0 or less, and even more preferably 3.5 or less.

[0075] The tack strength in the present disclosure is measured as described in the Examples.

[0076] <Method of manufacturing adhesive film> The adhesive film of the present disclosure can be manufactured by a known method. For example, the adhesive film can be manufactured by applying the adhesive layer forming composition to the substrate layer and drying it. Alternatively, the adhesive layer forming composition can be applied to a release-treated PET film, dried to form an adhesive layer, and then the adhesive layer can be transferred to the substrate layer, and the PET film can be peeled off to manufacture an adhesive film in which the adhesive layer and the substrate layer are laminated. The adhesive layer-forming composition contains at least two of the above-mentioned polymers, and may further contain other resin components and other components that are added as desired.

[0077] [Preparation of adhesive layer-forming composition] The method of preparing the adhesive layer forming composition is not particularly limited, and a known composition preparation method can be used. The solvent used to prepare the adhesive layer forming composition is not particularly limited, and it is preferably an organic solvent capable of dissolving the polymer. Examples of the organic solvent include toluene, methyl ethyl ketone, and ethyl acetate.

[0078] [Application and drying] The method of applying the adhesive layer-forming composition to the base layer is not particularly limited, and any known application method such as roll coating, bar coating, kiss coating, etc. The amount of the adhesive layer-forming composition applied is preferably adjusted appropriately so that the thickness of the composition layer formed after drying is close to the thickness of the desired adhesive layer. The method for drying the applied adhesive layer-forming composition is not particularly limited, and any known drying method can be used. For example, the composition may be dried at 50° C. to 150° C. for 0.1 to 60 minutes.

[0079] <Applications of adhesive film> The pressure-sensitive adhesive film of the present disclosure can be used in methods for producing electronic components such as semiconductor chips and ceramic capacitors.

[0080] Specifically, it is used in a process in which a plurality of semiconductor chips are arranged on an adhesive film, and then the adhesive film is stretched to expand the space between two adjacent semiconductor chips, and it can also be used in the processing or pick-up process of semiconductor chips.

[0081] The adhesive film in one embodiment of the present disclosure retains its adhesive strength even when stretched while preventing adhesive residue on the substrate. Therefore, even when a semiconductor chip is processed on the stretched adhesive film, the semiconductor chip can be held in place while preventing adhesive residue on the semiconductor chip.

[0082] <Method of Manufacturing Semiconductor Device> In the method for producing a semiconductor device according to the present disclosure, a semiconductor device is produced using the pressure-sensitive adhesive film according to the present disclosure. The pressure-sensitive adhesive film according to the present disclosure may be used as a dicing film or a dicing die bonding film.

[0083] For example, the method of manufacturing a semiconductor device according to the present disclosure includes expanding the space between two adjacent semiconductor chips by stretching the adhesive film according to the present disclosure, the semiconductor chips being arranged on one side thereof. After the stretching, the semiconductor chips can be peeled off from the adhesive film. The semiconductor chips may be obtained by placing a wafer on the adhesive film of the present disclosure and dicing the wafer, or by placing previously diced semiconductor chips on the adhesive film of the present disclosure.

[0084] After the adhesive film is stretched and before the semiconductor chip is peeled off, a step of processing the adhesive film into a semiconductor chip may be included. The processing may be to provide a functional layer. An example of the functional layer is an insulating layer. EXAMPLES

[0085] The above embodiment will be specifically described below with reference to examples, but the above embodiment is not limited to these examples.

[0086] (Acrylic Polymer 1) Acrylic polymer 1, which is a copolymer of the following monomers, was used. The SP value of acrylic polymer 1 was determined by the above-mentioned method. The SP value of acrylic polymer 1 is 10.3. The hydroxyl value is 2.5 mgKOH / g. Butyl acrylate: 88.1 parts by weight 2-Hydroxyethyl methacrylate: 0.6 parts by weight Acrylonitrile: 11.2 parts by weight The acrylic polymer 1 had an Mn of 140,000, an Mw of 910,000, and an Mw / Mn of 6.5.

[0087] (Acrylic Polymer 2) Acrylic polymer 2, which is a copolymer of the following monomers, was used. The SP value of acrylic polymer 2 is 10.0. The hydroxyl value is 31.1 mgKOH / g. Butyl acrylate: 92.2 parts by weight 4-Hydroxybutyl acrylate: 7.8 parts by weight The Mn of the acrylic polymer 2 was 133,000, the Mw was 1,039,000, and the Mw / Mn was 7.8.

[0088] (Acrylic Polymer 3) Acrylic polymer 3, which is a copolymer of the following monomers, was used. The SP value of acrylic polymer 3 is 10.1. The hydroxyl value is 46.7 mgKOH / g. Butyl acrylate: 88.7 parts by weight 4-Hydroxybutyl acrylate: 11.3 parts by weight The Mn of the acrylic polymer 3 was 130,000, the Mw was 1,040,000, and the Mw / Mn was 8.0.

[0089] (Acrylic Polymer 4) Acrylic polymer 4, which is a copolymer of the following monomers, was used. The SP value of acrylic polymer 4 is 9.9. The hydroxyl value is 15.6 mgKOH / g. Butyl acrylate: 95.9 parts by weight 4-Hydroxybutyl acrylate: 4.1 parts by weight The Mn of the acrylic polymer 4 was 130,000, the Mw was 1,040,000, and the Mw / Mn was 8.0.

[0090] (Acrylic Polymer 5) Acrylic polymer 5, which is a copolymer of the following monomers, was used. The SP value of acrylic polymer 5 is 11.0. The hydroxyl value is 19.5 mgKOH / g. Butyl acrylate: 71.2 parts by weight 2-Hydroxyethyl methacrylate: 4.8 parts by weight Acrylonitrile: 24.0 parts by weight The acrylic polymer 5 had an Mn of 140,000, an Mw of 610,000, and an Mw / Mn of 4.4.

[0091] (Synthesis of acrylic polymer 6) The following components were copolymerized by solution polymerization to obtain a polymer. 2-Hydroxyethyl acrylate: 25 parts by weight 2-Ethylhexyl acrylate: 75 parts by weight

[0092] To the obtained polymer, dibutylhydroxytoluene was added as a polymerization inhibitor, and dioctyltin dilaurate was added as a urethane catalyst, and then 16 parts by mass of 2-methacryloxyethyl isocyanate (Karens MOI, manufactured by Showa Denko K.K.) was added to obtain acrylic polymer 6. The SP value of acrylic polymer 6 is 10.4. The hydroxyl value is 120.8 mg KOH / g. The Mn of the acrylic polymer 6 was 140,000, the Mw was 500,000, and the Mw / Mn was 3.6.

[0093] (Preparation of Adhesive Layer-Forming Composition) The acrylic polymer shown in Table 1 below was dissolved in methyl ethyl ketone together with a crosslinking agent and a plasticizer to prepare a composition for forming an adhesive layer. The unit of the blend amount in Table 1 is parts by mass. As the crosslinking agent, Coronate L (manufactured by Tosoh Corporation, a TMP adduct of tolylene diisocyanate) was used. The amount added was 2.2 parts (parts by mass, solid content equivalent) with respect to 100 parts of the total blend amount of the acrylic polymer. D-810 (made by ADEKA Corporation, bis(2-ethylhexyl) terephthalate) was used as the plasticizer, and the amount added was 20 parts (parts by mass, solid content equivalent) per 100 parts of the total blend amount of the acrylic polymer.

[0094] (Preparation of adhesive film) The adhesive layer-forming composition was applied to the release-treated surface of a PET film having a thickness of 38 μm, one side of which was release-treated, so that the thickness after drying was 20 μm, and then dried to form an adhesive layer. Next, at room temperature (25° C.), the adhesive layer side of the PET film was attached to one side of a substrate, and the adhesive layer was transferred onto the substrate by pressing with a rubber roll, and the PET film was peeled off to produce an adhesive film having a substrate layer and an adhesive layer.

[0095] The base layer was a polyvinyl chloride film (thickness 120 μm) containing 44% by mass of a plasticizer (ADEKA CORPORATION, P-200) and 0.5% by mass of a pigment (phthalocyanine blue, maximum particle size 10 μm).

[0096] (Surface roughness measurement) The arithmetic mean height (Sa) value S before elongation and the arithmetic mean height (Sa) value S' at 200% elongation were measured by the method described above. The ratio S' / S was calculated from the measurement results and is shown in Table 2.

[0097] (Measurement of tackiness) The tack value A of the adhesive layer before the adhesive film was stretched by 200% was measured by the following method. The adhesive film is cut to a size of 20 mm wide and 100 mm long, and placed on the measurement part of the tack tester with the adhesive layer facing up. At 23±5°C, a SUS Φ5 mm probe is brought into contact with the adhesive layer, and the probe is lowered, pressed, and raised under the conditions of a probe lowering speed of 120 mm / min, a load of 50 gf, a pressure time of 1 second, and a probe rising speed of 600 mm / min. The obtained value is the tack value A.

[0098] The tack value A' of the adhesive layer when the adhesive film was stretched by 200% was measured by the following method. With the adhesive film stretched 200% using the method described above, a frame plate with a through hole of 10 mm diameter is pressed against the adhesive layer side of the adhesive film to adhere it. The frame plate with the adhesive film attached is placed in a tack tester so that the adhesive layer is the measurement surface. A probe is placed so that it passes through the through hole described above, and the probe is lowered, pressurized, and raised, and the value obtained is taken as tack value A'. The measurement conditions for tack value A' are the same as those for tack value A.

[0099] As a tack tester for measuring the tack value A and the tack value A', for example, a "Probe Tack Tester TAC-II" manufactured by Rhesca Corporation can be used. The ratio A' / A was calculated from the measurement results and is shown in Table 2.

[0100] (Adhesive residue evaluation) After laminating an adhesive film onto a mirror-finished SUS plate, the adhesive film was peeled off by hand to check for the presence of any resin components remaining on the surface of the SUS plate. The laminate was applied using a hand roller, and then pressed at 16 MPa for 5 minutes using a press machine heated to 80°C. The results are shown in Table 2.

[0101] [Table 1]

[0102] [Table 2]

[0103] As shown in Tables 1 and 2, Examples 1 to 3, in which (1) the ratio S' / S is 9.5 or less, or (2) the SP value difference of the polymer contained in the adhesive layer is 0.3 or less and the hydroxyl value ratio is 40 or less, had high tack strength even when stretched, and no adhesive residue was observed.

[0104] In contrast, in Comparative Examples 1 to 5, (1') the S' / S ratio exceeded 9.5, or (2') the SP value difference of the polymer contained in the adhesive layer exceeded 0.3 or the hydroxyl value ratio exceeded 40, resulting in low tack strength when stretched. No adhesive residue was observed in Comparative Examples 2 to 4, but adhesive residue was observed in Comparative Example 1. Comparative Examples 6 and 7 used only one type of polymer, and although the decrease in tackiness during elongation was suppressed, adhesive residue occurred. In Comparative Example 7, seepage of additives other than the polymer onto the SUS plate was confirmed. [Explanation of symbols]

[0105] 10 Base material layer 20 Adhesive layer 30 Adhesive film

Claims

1. An adhesive film comprising an adhesive layer containing two or more types of polymers and a base layer, The adhesive film has a ratio S' / S of the arithmetic mean height (Sa) of the surface of the adhesive layer when the adhesive film is stretched by 200% to the arithmetic mean height (Sa) of the surface of the adhesive layer of the adhesive film before stretching of 9.5 or less.

2. The pressure-sensitive adhesive film according to claim 1 , wherein the difference in SP value between at least two of the polymers is 0.3 or less.

3. The pressure-sensitive adhesive film according to claim 1 , wherein at least two of the polymers have a hydroxyl value ratio of 40 or less.

4. The adhesive layer includes two or more polymers, and a base layer. At least two of the polymers have a difference in SP value of 0.3 or less and a hydroxyl value ratio of 40 or less.

5. The pressure-sensitive adhesive film according to claim 1 or claim 4, wherein the value S of the arithmetic mean height (Sa) of the surface of the pressure-sensitive adhesive layer before stretching is 0.001 μm to 5.000 μm.

6. The adhesive film according to claim 1 or 4, wherein the content of the polymer having the highest content in the adhesive layer is 85 mass% or less with respect to the total content of the polymers contained in the adhesive layer.

7. A method for manufacturing a semiconductor device, comprising: expanding an adhesive film according to claim 1 or claim 4, the adhesive film having a surface on which a plurality of semiconductor chips are arranged, thereby expanding a space between two adjacent semiconductor chips.

8. The method for manufacturing a semiconductor device according to claim 7 , further comprising the step of peeling off the semiconductor chip from the adhesive film after the stretching.

9. 9. The method for manufacturing a semiconductor device according to claim 8, further comprising processing the semiconductor chip after the extension and before the peeling of the semiconductor chip.

10. The method for manufacturing a semiconductor device according to claim 9 , wherein the processing includes providing a functional layer on the semiconductor chip.

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