Protective film forming film

Abstract

To provide a film for forming a protective film with which sufficient print visibility can be obtained even when the line width of laser printing is narrow.SOLUTION: There is provided a sheet 1A for forming a protective film including a support sheet 10 which includes an adhesive layer 12 on a substrate 11 and which is a laminate of the substrate 11 and the adhesive layer 12, and a film 13 for forming a protective film on the adhesive layer 12, the film 13 for forming a protective film being laminated on one surface 10a of the support sheet 10. In the film for forming a protective film with a laser-printed surface, a color difference ΔE*ab between a printed part and a non-printed part defined by following expression (A) is 8 or more, when the color of the printed part has a brightness L*p, a chromaticity a*p and a chromaticity b*p in coordinates specified in the CIE 1976 L*a*b* color system, and the color of the non-printed part has a brightness L*N, a chromaticity a*N and a chromaticity b*N in coordinates specified in the CIE 1976 L*a*b* color system.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film for forming a protective film, which is attached to the back surface of a semiconductor wafer or a semiconductor chip and used to form a protective film, and a sheet for forming a protective film including the same. [Background technology]

[0002] In recent years, semiconductor devices have been manufactured using a mounting method called the face-down method. In this method, when mounting a semiconductor chip having a circuit surface on which electrodes such as bumps are formed, the circuit surface side of the semiconductor chip is bonded to a chip mounting portion such as a lead frame. This results in a structure in which the back side of the semiconductor chip on which no circuit is formed is exposed.

[0003] 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, for example, using a semiconductor backside film or a dicing tape-integrated wafer backside protective film as shown in Patent Document 1.

[0004] A protective film may also be used as a member for displaying information on a workpiece (e.g., a semiconductor wafer) or a processed product (e.g., a semiconductor chip) that includes the protective film. In other words, a printing process may be performed to visually display information on the workpiece or processed product by forming unevenness or light and dark areas on the surface of the protective film. This printing process is usually performed by irradiating the surface of the protective film with a laser. In the case of a semiconductor chip, the chip's manufacturer name or logo, product name, product number, specifications, and other chip attributes are printed.

[0005] In this regard, the film for semiconductor back surface in Patent Document 1 has a light transmittance of 20% or less at a wavelength of 532 nm or 1064 nm. This enables printing by irradiation with laser light and prevents the semiconductor element from being adversely affected by the laser light. There is a demand for improving the visibility of information based on the unevenness formed on the surface of the protective film by printing (also referred to as "print visibility" in this specification). Patent Document 2 teaches that the print visibility can be improved by setting the average particle size of the filler blended in the film for forming the protective film to 0.4 μm or less. However, in recent years, as semiconductor devices have become smaller, the tendency for print visibility to decrease has become more pronounced. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2012-28396 A [Patent Document 2] International Publication WO2015 / 146936 Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have considered the causes of the decrease in print visibility. The film for forming a protective film generally contains a thermosetting or energy ray curable resin, an additive such as a curing agent, a colorant, and a filler. Laser printing may be performed before the film for forming a protective film is cured, or laser printing may be performed on the cured protective film obtained by curing the film for forming a protective film. The printed information is then checked one by one, and the film is moved between each process, and finally transferred to the mounting process. At this time, if the visibility of the print is insufficient, the attributes of the chip may not be recognized or may be misrecognized, which may cause problems in the transfer between processes or in the mounting process.

[0008] In addition, the semiconductor chip having the laser-printed protective film is subjected to a reflow process in the mounting process. The reflow process is a process in which protruding solder provided on the substrate for mounting the chip or protruding solder provided on the semiconductor chip is melted to connect the substrate and the semiconductor chip. At this time, the semiconductor chip is heated to about 260°C. The semiconductor chip is connected to the substrate by the reflow process and is manufactured. However, there are cases where the visibility of the printing is reduced after the reflow process. The information printed on the chip is not only used in the assembly process of the semiconductor device, but also serves as an indication of the quality of the semiconductor device and has the function of improving the design. For this reason, it is required that the visibility of the printing is maintained even in the semiconductor device that has been manufactured.

[0009] On the other hand, there is a constant demand for smaller and more powerful semiconductor devices. As a result, the size of semiconductor chips is becoming smaller, down to a few square millimeters, and even to less than 1 square millimeter. As the chips become smaller, the area that can be laser-marked is becoming smaller, and the size of the marks becomes smaller, with the line width of the printed characters and figures sometimes becoming 30 μm or less.

[0010] From these facts, the inventors of the present invention have come to the conclusion that the line width of the printed characters is narrowed, and as a result, the line width is further narrowed by heating when the protective film-forming film is cured or by heating during reflow, which may lead to a decrease in print visibility. When the protective film-forming film is cured, the resin component contained in the protective film-forming film temporarily increases the fluidity, which may narrow the line width of the laser-printed portion. In addition, even if the protective film is cured, if it is exposed to a high temperature of about 260°C, the protective film will partially soften, causing the laser-printed portion to deform, which is thought to lead to a decrease in print visibility.

[0011] Therefore, an object of the present invention is to provide a film for forming a protective film that can provide sufficient print visibility even when the print line width is narrow. [Means for solving the problem]

[0012] The present inventors conducted extensive research to solve the above problems, and discovered that sufficient print visibility can be obtained even if the print line width is narrow by setting the color difference between the printed and non-printed areas to a predetermined value or more, which led to the completion of the present invention.

[0013] (1) A film for forming a protective film, the surface of which is laser-printed, CIE1976L * a * b * In the coordinates specified by the color system, the color of the printed part is expressed as lightness L * p , chromaticity a * p , chromaticity b * p And CIE1976L * a * b * In the coordinates specified by the color system, the color of the non-printed part is expressed as lightness L * N , chromaticity a * N , chromaticity b * N When I said that, The color difference ΔE between the printed and non-printed areas is defined by the following formula (A) * ab A film for forming a protective film, wherein the film has a molecular weight of 8 or more. ΔE * ab =〔(L * p -L * N ) 2 +(a * p -a * N ) 2 +(b * p -b * N ) 2 〕 1 / 2 …(A)

[0014] (2) The brightness difference ΔL between the printed and non-printed areas defined by the following formula (B): *The film for forming a protective film according to (1), wherein the value is 8 or more. ΔL * =〔(L * p -L * N ) 2 〕 1 / 2 …(B)

[0015] (3) Lightness L of the printed part * p and the brightness of the non-printed area L * N But, L * p >L * N The film for forming a protective film according to (1) or (2), which satisfies the above.

[0016] (4) A film for forming a protective film according to any one of (1) to (3), wherein the color of the printed area and the color of the non-printed area are measured after the film for forming a protective film is heated to 130°C and cured after laser printing.

[0017] (5) The color of the printed area and the color of the non-printed area are measured after the film for forming a protective film is heated to 180°C after laser printing, hardened, and then further heated at 260°C for 10.8 minutes three times. The film for forming a protective film described in any of (1) to (3).

[0018] (6) The film for forming a protective film according to any one of (1) to (5), wherein the printed portion includes a portion having a line width of 50 μm or less.

[0019] (7) A film for forming a protective film according to any one of (1) to (6) above, A support sheet; A sheet for forming a protective film comprising: Effect of the Invention

[0020] According to the present invention, it is possible to provide a film for forming a protective film that can provide sufficient print visibility even when the printed line width is narrow during the curing or reflow process of the film for forming a protective film. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Diagram 2] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Diagram 3] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Diagram 5] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Figure 6] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Figure 7] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Figure 8] FIG. 2 is a schematic diagram illustrating an example of a protective film-forming sheet according to the present embodiment. [Figure 9] 5A to 5C are schematic diagrams illustrating an example of a manufacturing process of the protective film-forming sheet according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Protective film forming film The protective film forming film is a curable film used to form a protective film on a workpiece such as a semiconductor wafer or a processed product (such as a semiconductor chip) obtained by processing the workpiece.

[0023] The film for forming a protective film according to this embodiment is finally attached to a workpiece such as a semiconductor chip and used as a protective film with laser printing on the surface. The film for forming a protective film according to this embodiment has a surface that has been altered by irradiation with laser light, and has a printed area on which characters, figures, etc. are formed, and a non-printed area that is not irradiated with laser light.

[0024] In the protective film forming film according to this embodiment, CIE1976L * a * b * In the coordinates specified by the color system, the color of the printed part is expressed as lightness L * p , chromaticity a * p , chromaticity b * p And CIE1976L * a * b * In the coordinates specified by the color system, the color of the non-printed part is expressed as lightness L * N , chromaticity a * N , chromaticity b * N When the color difference between the printed and non-printed areas is * ab is 8 or more, preferably 10 or more, and more preferably 15 or more. * ab The upper limit of is not particularly limited, but in consideration of the design, it is preferably 120 or less, more preferably 90 or less, and even more preferably 80 or less. * ab If the value is 8 or more, the print visibility is maintained even when the protective film-forming film is exposed to heat for curing or reflowing in a narrow print width. In addition, the color difference ΔE * ab is defined by the following formula (A). ΔE * ab =〔(L * p -L * N ) 2 +(a * p -a * N ) 2 +(b * p -b * N ) 2 〕 1 / 2 …(A)

[0025] In the protective film forming film according to this embodiment, the brightness difference ΔL between the printed portion and the non-printed portion * is preferably 8 or more, and more preferably 10 or more. * The upper limit of the lightness difference ΔL is not particularly limited, but in consideration of the design, it is preferably 85 or less, more preferably 70 or less, and even more preferably 60 or less. * If the value is 8 or more, the print visibility is maintained even when the protective film-forming film is exposed to heat for curing or reflowing in a narrow print width. In addition, the brightness difference ΔL * is defined by the following formula (B). ΔL * =〔(L * p -L * N ) 2 〕 1 / 2 …(B)

[0026] In the protective film forming film according to this embodiment, the lightness L * p and the brightness of the non-printed area L * N But, L * p >L * N It is more preferable that L * p >1.5×L * N It is more preferable that the lightness L of the printed portion is * p is the brightness of the non-printed area L * N When the value is higher than 100%, the print appears to stand out against a dark background, resulting in excellent print visibility.

[0027] Color difference ΔE in this embodiment * ab It is sufficient if the lightness difference ΔL is within the above range immediately after laser marking, but it is preferable that the lightness difference ΔL is within the above range in all steps after laser marking. * The same applies to.

[0028] When laser marking is performed on an uncured protective film, the color difference ΔE * ab and the brightness difference ΔL * In addition, when the protective film is hardened to form a protective film and then laser printing is performed on the protective film, the color difference ΔE * ab and the brightness difference ΔL * is preferably in the above range.

[0029] The film for forming a protective film may be either heat curable or energy ray curable. When the film for forming a protective film is heat curable, the heat curing conditions are various. In this embodiment, the color difference ΔE * ab and the brightness difference ΔL * When evaluating the color difference ΔE, the protective film obtained by heating and curing the protective film-forming film at 180°C for a sufficient period of time is * ab and the brightness difference ΔL * Rate the following.

[0030] When mounting a chip having a protective film on a substrate, the solder is melted in a reflow process to connect the chip and the substrate. The heating conditions in the reflow process are not particularly limited. In this embodiment, the color difference ΔE * ab and the brightness difference ΔL * When evaluating the color difference ΔE of the protective film after heating a chip with a protective film at 260°C for 10.8 minutes three times, simulating the reflow conditions, * ab and the brightness difference ΔL * Rate the following.

[0031] According to the present invention, even if the line width of the print is narrow, sufficient print visibility can be obtained even after the protective film forming film is cured or after the reflow process. If the line width of the print is narrow, the print part with a particularly narrow line width becomes even narrower during the curing or reflow process of the protective film forming film, and the print visibility decreases. However, according to the protective film forming film of this embodiment, there is a sufficient color difference between the printed part and the non-printed part, so that even if the line width of the print is narrowed after the protective film forming film is cured or after the reflow process, sufficient print visibility can be obtained. Therefore, the protective film forming film according to this embodiment is particularly preferably used when the printed part has a part with a width of 50 μm or less.

[0032] The protective film forming film according to this embodiment may have a release film on one side or on both sides. When the release film is on both sides, the release film may be the same on both sides or different. By having a release film, the protective film forming film according to this embodiment can be provided as a long film wound in a roll. The release film is not particularly limited, but the same release film as that used in the protective film forming sheet described later can be used.

[0033] The film for forming a protective film according to this embodiment is cured to become a protective film. This protective film is intended to protect the back surface (the surface opposite to the electrode formation surface) of a semiconductor wafer or a semiconductor chip. The film for forming a protective film is soft and can be easily attached to an object to which it is to be attached.

[0034] Non-limiting examples of materials and manufacturing methods for the protective film-forming film according to this embodiment are shown below.

[0035] The protective film is CIE1976L * a * b * The color difference ΔE between the printed and non-printed areas in the coordinates specified by the color system * abAs long as the above is satisfied, the film for forming a protective film may be either heat curable or energy ray curable. The film for forming a protective film is cured to finally become a protective film having high impact resistance. This protective film can prevent cracks from occurring in the semiconductor chip after the dicing process, for example, and can also easily detect the semiconductor chip with the protective film in the state of being stored in the carrier tape.

[0036] The film for forming a protective film can be formed using a composition for a thermosetting film for forming a protective film or an energy ray curable composition for a film for forming a protective film (hereinafter, these may be collectively referred to as "composition for a film for forming a protective film") described below.

[0037] The film for forming a protective film may be only one layer (single layer) or may be two or more layers. If it is multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0038] The thickness of the film for forming a protective film is not particularly limited, but is preferably 1 to 100 μm, more preferably 5 to 75 μm, and particularly preferably 5 to 50 μm. When the thickness of the film for forming a protective film is equal to or greater than the lower limit, the effect of preventing damage to the semiconductor wafer caused by penetration of the laser is enhanced when the protective film or the film for forming a protective film is irradiated with a laser to perform laser printing. In addition, the protective ability of the protective film is improved. On the other hand, when the thickness of the film for forming a protective film is equal to or less than the upper limit, the degree of shrinkage during curing of the film is reduced, and the effect of reducing warpage of the semiconductor chip with the protective film is enhanced. In addition, during a temperature cycle test, the generation of stress caused by the difference in linear expansion coefficient between the protective film and the semiconductor wafer is suppressed, and the effect of suppressing peeling of the protective film from the semiconductor wafer is enhanced.

[0039] Here, "thickness of the film for forming a protective film" means the overall thickness of the film for forming a protective film, and for example, the thickness of a film for forming a protective film consisting of multiple layers means the total thickness of all layers that constitute the film for forming a protective film.

[0040] Below, we will explain the case where the film for forming a protective film in this embodiment is a film for forming a thermosetting protective film formed from a film composition for forming a thermosetting protective film, and the case where the film for forming an energy ray curable protective film is formed from a film composition for forming an energy ray curable protective film.

[0041] ·Thermosetting protective film Examples of the film for forming a thermosetting protective film include those containing a polymer component (A) and a thermosetting component (B) described below. The polymer component (A) is a component that can be considered to be formed by a polymerization reaction of a polymerizable compound. The thermosetting component (B) is a component that can undergo a curing (polymerization) reaction using heat as a reaction trigger. In the present invention, the polymerization reaction also includes a polycondensation reaction.

[0042] <<Thermosetting protective film composition>> The film for forming a thermosetting protective film can be formed from a composition for forming a thermosetting protective film containing its constituent materials. For example, the composition for forming a thermosetting protective film can be applied to the surface of the film to be formed, and dried as necessary to form the film for forming a thermosetting protective film at the desired location. The ratio of the contents of the components that do not vaporize at room temperature in the composition for forming a thermosetting protective film is usually the same as the ratio of the contents of the components in the film for forming a thermosetting protective film.

[0043] In this specification, "room temperature" refers to a temperature that is neither particularly cooled nor heated, that is, an ordinary temperature, and examples thereof include temperatures of 15 to 25°C.

[0044] The coating of the composition for forming a thermosetting protective film may be carried out by a known method, for example, a method using various coaters such as an air knife coater, a blade coater, a bar coater, a gravure coater, a roll coater, a roll knife coater, a curtain coater, a die coater, a knife coater, a screen coater, a Mayer bar coater, or a kiss coater.

[0045] The drying conditions for the composition for forming a thermosetting protective film are not particularly limited. However, when the composition for forming a thermosetting protective film contains a solvent as described below, it is preferable to heat dry the composition. In this case, it is preferable to dry the composition at 70 to 130°C for 10 seconds to 5 minutes.

[0046] <Composition for forming protective film (1)> Examples of compositions for films for forming thermosetting protective films include a composition for films for forming thermosetting protective films (1) (sometimes abbreviated in this specification as "composition for films for forming protective films (1)") that contains a polymer component (A) and a thermosetting component (B).

[0047] [Polymer component (A)] The polymer component (A) is a polymer compound for imparting film-forming properties, flexibility, and the like to the thermosetting protective film-forming film.

[0048] The polymer component (A) contained in the composition for forming a protective film (1) and the thermosetting film for forming a protective film may be one type or two or more types. If there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0049] Examples of the polymer component (A) include acrylic resins (e.g., resins having a (meth)acryloyl group), polyester, urethane resins (e.g., resins having a urethane bond), acrylic urethane resins, silicone resins (e.g., resins having a siloxane bond), rubber resins (e.g., resins having a rubber structure), phenoxy resins, and thermosetting polyimides, with acrylic resins being preferred.

[0050] The acrylic resin in the polymer component (A) may be any known acrylic polymer.

[0051] The weight-average molecular weight (Mw) of the acrylic resin is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. When the weight-average molecular weight of the acrylic resin is equal to or greater than the lower limit, the shape stability (stability over time during storage) of the thermosetting protective film-forming film is improved. In addition, when the weight-average molecular weight of the acrylic resin is equal to or less than the upper limit, the thermosetting protective film-forming film is more likely to conform to the uneven surface of the adherend, and the occurrence of voids and the like between the adherend and the thermosetting protective film-forming film is more suppressed.

[0052] In this specification, unless otherwise specified, the "weight average molecular weight" refers to a polystyrene equivalent value measured by gel permeation chromatography (GPC).

[0053] The glass transition temperature (Tg) of the acrylic resin is preferably −60 to 70° C., more preferably −30 to 50° C. When the Tg of the acrylic resin is equal to or higher than the lower limit, the adhesive strength between the protective film and the support sheet is suppressed, improving the peelability of the support sheet. When the Tg of the acrylic resin is equal to or lower than the upper limit, the adhesive strength between the thermosetting protective film-forming film and the protective film and the adherend is improved.

[0054] In this specification, the term "glass transition temperature" refers to the temperature of the inflection point of a DSC curve obtained by measuring a DSC curve of a sample using a differential scanning calorimeter.

[0055] Examples of acrylic resins include polymers of one or more (meth)acrylic acid esters; copolymers of at least two monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.

[0056] Examples of the (meth)acrylic acid ester constituting the acrylic resin include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isopropyl (meth)acrylate, (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure having 1 to 18 carbon atoms, such as sononyl, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (also called lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (also called myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (also called palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (also called stearyl (meth)acrylate); (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester; (Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester; (Meth)acrylic acid imide; glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; hydroxyl group-containing (meth)acrylic acid esters such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Examples of the substituted amino group-containing (meth)acrylic acid ester include N-methylaminoethyl (meth)acrylate. Here, the term "substituted amino group" refers to a group in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom.

[0057] Of the above, n-butyl acrylate, methyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, and the like are preferred.

[0058] The acrylic resin may be, for example, a copolymer of the above-mentioned (meth)acrylic acid ester with one or more monomers selected from (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, N-methylolacrylamide, and the like.

[0059] The monomer constituting the acrylic resin may be one type only, or two or more types. When two or more types are used, the combination and ratio thereof can be selected arbitrarily.

[0060] The acrylic resin may have a functional group capable of bonding with other compounds, such as a vinyl group, a (meth)acryloyl group, an amino group, a hydroxyl group, a carboxyl group, an isocyanate group, etc. The functional group of the acrylic resin may be bonded with other compounds via a crosslinking agent (F) described later, or may be bonded directly with other compounds without the crosslinking agent (F). The acrylic resin is bonded with other compounds via the functional group, which tends to improve the reliability of the package obtained by using the sheet for forming a protective film.

[0061] In the present invention, as the polymer component (A), a thermoplastic resin other than an acrylic resin (hereinafter sometimes simply abbreviated as a "thermoplastic resin") may be used in combination with an acrylic resin.

[0062] By using the above-mentioned thermoplastic resin, the peelability of the protective film from the support sheet can be improved, and the film for forming a thermosetting protective film can easily conform to the uneven surface of the adherend, which can further suppress the occurrence of voids, etc. between the adherend and the film for forming a thermosetting protective film.

[0063] The weight average molecular weight of the thermoplastic resin is preferably 1,000 to 100,000, and more preferably 3,000 to 80,000.

[0064] The glass transition temperature (Tg) of the thermoplastic resin is preferably from -30 to 150°C, and more preferably from -20 to 120°C.

[0065] Examples of the thermoplastic resin include polyester, polyurethane, phenoxy resin, polybutene, polybutadiene, and polystyrene.

[0066] The above thermoplastic resin contained in the composition for forming a protective film (1) and the film for forming a thermosetting protective film may be one type or two or more types, and if there are two or more types, their combination and ratio can be selected arbitrarily.

[0067] The content of the polymer component (A) is based on the total mass of all components other than the solvent constituting the composition (1) for the film for forming a protective film (i.e., the total mass of the film for forming a thermosetting protective film), regardless of the type of the polymer component (A). In quantity The content is preferably 5 to 50 mass %, more preferably 10 to 40 mass %, and particularly preferably 15 to 35 mass %, relative to the total mass of the water.

[0068] The polymer component (A) may also correspond to the thermosetting component (B). In the present invention, when the composition for a film for forming a protective film (1) contains a component that corresponds to both the polymer component (A) and the thermosetting component (B), the composition for a film for forming a protective film (1) is considered to contain the polymer component (A) and the thermosetting component (B).

[0069] [Thermosetting component (B)] The thermosetting component (B) is a component for curing the thermosetting film for forming a protective film to form a hard protective film.

[0070] The composition for a film for forming a protective film (1) and the thermosetting component (B) contained in the film for forming a thermosetting protective film may be one type or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0071] Examples of the thermosetting component (B) include epoxy-based thermosetting resins, thermosetting polyimides, polyurethanes, unsaturated polyesters, silicone resins, etc., with epoxy-based thermosetting resins being preferred.

[0072] (Epoxy thermosetting resin) The epoxy thermosetting resin comprises an epoxy resin (B1) and a thermosetting agent (B2).

[0073] The epoxy-based thermosetting resin contained in the composition for forming a protective film (1) and the film for forming a thermosetting protective film may be one type or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0074] Epoxy resin (B1) The epoxy resin (B1) may be any known epoxy resin, such as a polyfunctional epoxy resin, a biphenyl compound, bisphenol A diglycidyl ether and its hydrogenated product, orthocresol novolac epoxy resin, a dicyclopentadiene type epoxy resin, a biphenyl type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a phenylene skeleton type epoxy resin.

[0075] Among the above, bisphenol A type epoxy resins, dicyclopentadiene type epoxy resins, etc. are preferred.

[0076] As the epoxy resin (B1), an epoxy resin having an unsaturated hydrocarbon group may be used. The epoxy resin having an unsaturated hydrocarbon group has a higher compatibility with acrylic resin than the epoxy resin having no unsaturated hydrocarbon group. Therefore, by using the epoxy resin having an unsaturated hydrocarbon group, the reliability of the package obtained by using the sheet for forming a protective film is improved.

[0077] Examples of epoxy resins having unsaturated hydrocarbon groups include compounds obtained by converting a part of the epoxy groups of a polyfunctional epoxy resin into groups having unsaturated hydrocarbon groups. Such compounds can be obtained, for example, by subjecting the epoxy groups to an addition reaction with (meth)acrylic acid or a derivative thereof.

[0078] In this specification, the term "derivative" refers to a compound in which at least one hydrogen atom of the original compound has been replaced with a group (substituent) other than a hydrogen atom.

[0079] Furthermore, examples of epoxy resins having an unsaturated hydrocarbon group include compounds in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring or the like constituting the epoxy resin.

[0080] The unsaturated hydrocarbon group is a polymerizable unsaturated group, and specific examples thereof include an ethenyl group (vinyl group), a 2-propenyl group (allyl group), a (meth)acryloyl group, and a (meth)acrylamide group, with an acryloyl group being preferred.

[0081] The number average molecular weight of the epoxy resin (B1) is not particularly limited, but from the viewpoints of the curability of the film for forming a thermosetting protective film and the strength and heat resistance of the protective film after curing, it is preferably 300 to 30,000, more preferably 300 to 10,000, and particularly preferably 300 to 3,000.

[0082] In this specification, unless otherwise specified, the "number average molecular weight" refers to the number average molecular weight expressed as a value converted into standard polystyrene measured by gel permeation chromatography (GPC).

[0083] The epoxy equivalent of the epoxy resin (B1) is preferably from 100 to 1100 g / eq, and more preferably from 150 to 1000 g / eq.

[0084] In this specification, the term "epoxy equivalent" means the number of grams (g / eq) of an epoxy compound containing 1 gram equivalent of epoxy groups, and can be measured according to the method of JIS K 7236:2001.

[0085] The epoxy resin (B1) may be used alone or in combination of two or more kinds. When two or more kinds are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0086] ·Heat hardener (B2) The heat curing agent (B2) functions as a curing agent for the epoxy resin (B1).

[0087] The thermosetting agent (B2) may be, for example, a compound having at least two functional groups capable of reacting with an epoxy group in one molecule. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an anhydride group of an acid group, and the like. A phenolic hydroxyl group, an amino group, or an anhydride group of an acid group is preferable, and a phenolic hydroxyl group or an amino group is more preferable.

[0088] Among the heat curing agents (B2), examples of phenolic curing agents having a phenolic hydroxyl group include polyfunctional phenolic resins, biphenols, novolac-type phenolic resins, dicyclopentadiene-based phenolic resins, and aralkylphenolic resins.

[0089] Among the heat curing agents (B2), examples of amine-based curing agents having an amino group include dicyandiamide.

[0090] The heat curing agent (B2) may have an unsaturated hydrocarbon group.

[0091] Examples of the heat curing agent (B2) having an unsaturated hydrocarbon group include a compound in which some of the hydroxyl groups of a phenol resin are substituted with a group having an unsaturated hydrocarbon group, and a compound in which a group having an unsaturated hydrocarbon group is directly bonded to an aromatic ring of a phenol resin.

[0092] The unsaturated hydrocarbon group in the heat curing agent (B2) is the same as the unsaturated hydrocarbon group in the above-mentioned epoxy resin having an unsaturated hydrocarbon group.

[0093] When a phenol-based curing agent is used as the heat curing agent (B2), it is preferable that the heat curing agent (B2) has a high softening point or glass transition temperature, since this improves the peelability of the protective film from the support sheet.

[0094] The heat curing agent (B2) is preferably a heat curing agent that is solid at room temperature and does not exhibit curing activity toward the epoxy resin (B1), but melts upon heating and exhibits curing activity toward the epoxy resin (B1) (hereinafter, sometimes abbreviated as "heat-activated latent epoxy resin curing agent").

[0095] In this specification, "room temperature" refers to a temperature that is neither particularly cooled nor heated, that is, an ordinary temperature, and examples thereof include temperatures of 15 to 25°C.

[0096] The above-mentioned heat-activated latent epoxy resin curing agent is stably dispersed in the epoxy resin (B1) in the film for forming a thermosetting protective film at room temperature, but becomes compatible with the epoxy resin (B1) by heating and reacts with the epoxy resin (B1). By using the above-mentioned heat-activated latent epoxy resin curing agent, the storage stability of the sheet for forming a protective film is significantly improved. For example, the migration of the curing agent from the film for forming a protective film to the adjacent support sheet is suppressed, and the decrease in the thermosetting property of the film for forming a thermosetting protective film is effectively suppressed. And, since the degree of thermosetting by heating of the film for forming a thermosetting protective film is increased, the pick-up property of the semiconductor chip with a protective film described later is further improved.

[0097] Examples of the heat-activatable latent epoxy resin curing agent include onium salts, dibasic acid hydrazides, dicyandiamide, and amine adducts of curing agents.

[0098] Of the thermosetting agents (B2), for example, the number average molecular weight of resin components such as polyfunctional phenol resins, novolac type phenol resins, dicyclopentadiene-based phenol resins, and aralkyl phenol resins is preferably 300 to 30,000, more preferably 400 to 10,000, and particularly preferably 500 to 3,000.

[0099] Of the thermosetting agent (B2), the molecular weight of the non-resin components, such as biphenol and dicyandiamide, is not particularly limited, but is preferably 60 to 500, for example.

[0100] The heat curing agent (B2) may be used alone or in combination of two or more kinds. When two or more kinds are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0101] In the composition for a film for forming a protective film (1) and the film for forming a thermosetting protective film, the content of the thermosetting curing agent (B2) is preferably 0.1 to 500 parts by mass, more preferably 1 to 200 parts by mass, relative to 100 parts by mass of the content of the epoxy resin (B1). When the content of the thermosetting curing agent (B2) is equal to or more than the lower limit, the curing of the film for forming a thermosetting protective film proceeds more easily. In addition, when the content of the thermosetting curing agent (B2) is equal to or less than the upper limit, the moisture absorption rate of the film for forming a thermosetting protective film is reduced, and the reliability of the package obtained using the sheet for forming a protective film is further improved.

[0102] In the composition for a film for forming a protective film (1) and the thermosetting film for forming a protective film, the content of the thermosetting component (B) (e.g., the total content of the epoxy resin (B1) and the thermosetting agent (B2)) is preferably 1 to 100 parts by mass, more preferably 1.5 to 85 parts by mass, and particularly preferably 2 to 70 parts by mass, per 100 parts by mass of the content of the polymer component (A). When the content of the thermosetting component (B) is within such a range, the adhesive strength between the protective film and the support sheet is suppressed, and the peelability of the support sheet is improved.

[0103] In another aspect, in the composition for a film for forming a protective film (1) and the film for forming a thermosetting protective film, the content of the thermosetting component (B) is preferably 1 to 90 mass%, more preferably 10 to 80 mass%, and even more preferably 30 to 70 mass%, based on the total mass of all components other than the solvent in the composition for a film for forming a protective film (1) (i.e., based on the total mass of the film for forming a thermosetting protective film).

[0104] [Cure accelerator (C)] The composition for a film for forming a protective film (1) and the thermosetting film for forming a protective film may contain a curing accelerator (C). The curing accelerator (C) is a component for adjusting the curing speed of the composition for a film for forming a protective film (1).

[0105] Preferred examples of the curing accelerator (C) include tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; imidazoles (imidazoles in which at least one hydrogen atom is substituted with a group other than a hydrogen atom) such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole; organic phosphines (phosphines in which at least one hydrogen atom is substituted with an organic group) such as tributylphosphine, diphenylphosphine, and triphenylphosphine; and tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.

[0106] Of the above, 2-phenyl-4,5-dihydroxymethylimidazole is preferred.

[0107] The curing accelerator (C) contained in the composition for forming a protective film (1) and the thermosetting film for forming a protective film may be one type or two or more types. If there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0108] When the curing accelerator (C) is used, the content of the curing accelerator (C) in the composition for the film for forming a protective film (1) and the film for forming a thermosetting protective film is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the content of the thermosetting component (B). When the content of the curing accelerator (C) is equal to or more than the lower limit, the effect of using the curing accelerator (C) is more remarkable. In addition, when the content of the curing accelerator (C) is equal to or less than the upper limit, for example, the effect of suppressing the highly polar curing accelerator (C) from migrating to the adhesive interface side with the adherend and segregating in the film for forming a thermosetting protective film under high temperature and high humidity conditions is enhanced, and the reliability of the package obtained using the sheet for forming a protective film is further improved.

[0109] [Filling material (D)] The composition for a film for forming a protective film (1) and the thermosetting film for forming a protective film may contain a filler (D). When the film for forming a thermosetting protective film contains the filler (D), the protective film obtained by curing the film for forming a thermosetting protective film can easily adjust the thermal expansion coefficient, and by optimizing this thermal expansion coefficient for the object on which the protective film is to be formed, the reliability of the package obtained using the sheet for forming a protective film is further improved. In addition, when the film for forming a thermosetting protective film contains the filler (D), the moisture absorption rate of the protective film can be reduced and the heat dissipation can be improved.

[0110] The filler (D) may be either an organic filler or an inorganic filler, but is preferably an inorganic filler.

[0111] Examples of preferred inorganic fillers include powders of silica, alumina, talc, calcium carbonate, titanium white, red iron oxide, silicon carbide, boron nitride, etc.; beads obtained by spheroidizing these inorganic fillers; surface-modified products of these inorganic fillers; single crystal fibers of these inorganic fillers; glass fibers, etc. Among these, the inorganic filler is preferably silica or alumina.

[0112] The average particle size of the filler (D) is preferably 0.1 to 10 μm. By setting the particle size of the filler (D) within the above range, the smoothness of the film for forming a protective film can be maintained and the filling property can also be increased.

[0113] The filler (D) contained in the composition for forming a protective film (1) and the thermosetting film for forming a protective film may be one type or two or more types, and if there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0114] When the filler (D) is used, the content of the filler (D) in the composition for forming a protective film (1) relative to the total content (total mass) of all components other than the solvent (i.e., the content of the filler (D) in the thermosetting film for forming a protective film) is preferably 5 to 80 mass%, more preferably 7 to 60 mass%. When the content of the filler (D) is in such a range, it becomes easier to adjust the thermal expansion coefficient.

[0115] [Coupling agent (E)] The composition for a film for forming a protective film (1) and the thermosetting film for forming a protective film may contain a coupling agent (E). By using a coupling agent (E) having a functional group capable of reacting with an inorganic compound or an organic compound, the adhesiveness and adhesion of the film for forming a thermosetting protective film to an adherend can be improved. In addition, by using the coupling agent (E), the protective film obtained by curing the film for forming a thermosetting protective film has improved water resistance without impairing heat resistance.

[0116] The coupling agent (E) is preferably a compound having a functional group capable of reacting with the functional groups of the polymer component (A), the thermosetting component (B), etc., and is more preferably a silane coupling agent.

[0117] Examples of the silane coupling agent include 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, and 3-(2-aminoethylamino)propyltrimethoxysilane. Examples of the silane include bis(3-(triethoxysilylpropyl)tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazole silane.

[0118] The coupling agent (E) contained in the composition for a film for forming a protective film (1) and the thermosetting film for forming a protective film may be one type or two or more types, and if there are two or more types, their combination and ratio can be selected arbitrarily.

[0119] When the coupling agent (E) is used, the content of the coupling agent (E) in the composition for a film for forming a protective film (1) and the film for forming a thermosetting protective film is preferably 0.03 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the total content of the polymer component (A) and the thermosetting component (B). When the content of the coupling agent (E) is equal to or more than the lower limit, the effects of using the coupling agent (E), such as improvement in dispersibility of the filler (D) in the resin and improvement in adhesion of the film for forming a thermosetting protective film to the adherend, are more significantly obtained. In addition, when the content of the coupling agent (E) is equal to or less than the upper limit, the generation of outgassing is more suppressed.

[0120] [Crosslinker (F)] When the polymer component (A) is one having a functional group such as a vinyl group, (meth)acryloyl group, amino group, hydroxyl group, carboxyl group, isocyanate group, etc., which can be bonded to other compounds, such as the above-mentioned acrylic resin, the composition for the film for forming a protective film (1) and the thermosetting film for forming a protective film may further contain a crosslinking agent (F) for bonding the functional group to other compounds to crosslink them. By crosslinking using the crosslinking agent (F), the initial adhesive strength and cohesive strength of the film for forming a thermosetting protective film can be adjusted.

[0121] Examples of the crosslinking agent (F) include organic polyvalent isocyanate compounds, organic polyvalent imine compounds, metal chelate crosslinking agents (crosslinking agents having a metal chelate structure), and aziridine crosslinking agents (crosslinking agents having an aziridinyl group).

[0122] Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds (hereinafter, these compounds may be collectively referred to as "aromatic polyisocyanate compounds, etc."); trimers, isocyanurates, and adducts of the aromatic polyisocyanate compounds, etc.; and terminal isocyanate urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, etc. with polyol compounds. The "adduct" refers to a reaction product of the aromatic polyisocyanate compound, aliphatic polyisocyanate compound, or alicyclic polyisocyanate compound with a low molecular weight active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil, and examples thereof include a xylylene diisocyanate adduct of trimethylolpropane, as described below. In addition, 、「 The term "isocyanate-terminated urethane prepolymer" refers to a prepolymer having a urethane bond and an isocyanate group at the terminal of the molecule.

[0123] More specific examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; a compound in which one or more of tolylene diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are added to all or a portion of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, and the like.

[0124] Examples of the organic polyvalent imine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine, and the like.

[0125] When an organic polyisocyanate compound is used as the crosslinking agent (F), it is preferable to use a hydroxyl group-containing polymer as the polymer component (A). When the crosslinking agent (F) has an isocyanate group and the polymer component (A) has a hydroxyl group, a crosslinked structure can be easily introduced into the thermosetting protective film-forming film by the reaction between the crosslinking agent (F) and the polymer component (A).

[0126] The crosslinking agent (F) contained in the composition for forming a protective film (1) and the thermosetting film for forming a protective film may be one type or two or more types. If there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0127] When the crosslinking agent (F) is used, the content of the crosslinking agent (F) in the composition for the film for forming a protective film (1) is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the polymer component (A). When the content of the crosslinking agent (F) is equal to or more than the lower limit, the effect of using the crosslinking agent (F) is more remarkable. When the content of the crosslinking agent (F) is equal to or less than the upper limit, the adhesive strength of the thermosetting film for forming a protective film to the support sheet and the adhesive strength of the thermosetting film for forming a protective film to the semiconductor wafer or semiconductor chip are prevented from excessively decreasing. In the present invention, the effect of the present invention can be sufficiently obtained even without using the crosslinking agent (F).

[0128] [Energy ray curable resin (G)] The composition for forming a protective film (1) may contain an energy ray curable resin (G). By containing the energy ray curable resin (G), the thermosetting film for forming a protective film can change its properties by irradiation with energy rays.

[0129] The energy ray curable resin (G) is obtained by polymerizing (curing) an energy ray curable compound.

[0130] The energy ray-curable compound includes, for example, a compound having at least one polymerizable double bond in the molecule, and an acrylate-based compound having a (meth)acryloyl group is preferable.

[0131] Examples of the acrylate-based compounds include trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. cyclic aliphatic skeleton-containing (meth)acrylates such as dicyclopentanyl di(meth)acrylate; polyalkylene glycol (meth)acrylates such as polyethylene glycol di(meth)acrylate; oligoester (meth)acrylates; urethane (meth)acrylate oligomers; epoxy-modified (meth)acrylates; polyether (meth)acrylates other than the above polyalkylene glycol (meth)acrylates; and itaconic acid oligomers.

[0132] The weight average molecular weight of the energy ray-curable compound is preferably from 100 to 30,000, and more preferably from 300 to 10,000.

[0133] The energy ray-curable compound used in the polymerization may be one kind or two or more kinds, and when two or more kinds are used, the combination and ratio thereof can be selected arbitrarily.

[0134] The energy ray curable resin (G) contained in the composition for forming a protective film (1) may be one type or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0135] In the composition for forming a protective film (1), the content of the energy ray curable resin (G) is preferably 1 to 95 mass%, more preferably 2 to 90 mass%, and particularly preferably 3 to 85 mass%, based on the total mass of all components other than the solvent in the composition for forming a protective film (1).

[0136] [Photopolymerization initiator (H)] When the composition for a film for forming a protective film (1) contains an energy ray curable resin (G), it may contain a photopolymerization initiator (H) in order to efficiently proceed with the polymerization reaction of the energy ray curable resin (G).

[0137] Examples of the photopolymerization initiator (H) in the composition for a protective film (1) include the same photopolymerization initiators as those in the pressure-sensitive adhesive composition (i).

[0138] The photopolymerization initiator (H) contained in the composition for forming a protective film (1) may be one type or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0139] In the composition for protective film formation (1), the content of the photopolymerization initiator (H) is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, and particularly preferably 2 to 5 parts by mass, relative to 100 parts by mass of the content of the energy ray curable resin (G).

[0140] [Colorant (I)] The composition for forming a protective film (1) is CIE1976L * a * b * The color difference ΔE between the printed and non-printed areas in the coordinates specified by the color system * ab From the viewpoint of obtaining a film for forming a protective film that satisfies the above-mentioned requirements, it is preferable that the film contains a colorant (I).

[0141] As the colorant (I), CIE1976L * a * b * The color difference ΔE between the printed and non-printed areas in the coordinates specified by the color system * ab However, there are no particular limitations as long as a protective film that satisfies the above requirements can be obtained, and for example, known pigments such as inorganic pigments, organic pigments, and organic dyes can be used.

[0142] Examples of the organic pigments and organic dyes include aminium-based dyes, cyanine-based dyes, merocyanine-based dyes, croconium-based dyes, squalium-based dyes, azulenium-based dyes, polymethine-based dyes, naphthoquinone-based dyes, pyrylium-based dyes, phthalocyanine-based dyes, naphthalocyanine-based dyes, naphtholactam-based dyes, azo-based dyes, condensed azo-based dyes, indigo-based dyes, perinone-based dyes, perylene-based dyes, dioxazine-based dyes, quinacridone-based dyes, isoindolinone-based dyes, quinophthalone-based dyes, pyrrole-based dyes, thioindigo-based dyes, metal complex-based dyes (metal complex dyes), dithiol metal complex-based dyes, indolephenol-based dyes, triarylmethane-based dyes, anthraquinone-based dyes, naphthol-based dyes, azomethine-based dyes, benzimidazolone-based dyes, pyranthrone-based dyes, and threne-based dyes.

[0143] Examples of the inorganic pigments include carbon black, cobalt-based pigments, iron-based pigments, chromium-based pigments, titanium-based pigments, vanadium-based pigments, zirconium-based pigments, molybdenum-based pigments, ruthenium-based pigments, platinum-based pigments, ITO (indium tin oxide)-based pigments, and ATO (antimony tin oxide)-based pigments.

[0144] The colorant (I) contained in the composition for forming a protective film (1) may be one type or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0145] The content of the colorant (I) in the thermosetting protective film is CIE1976L * a * b * The color difference ΔE between the printed and non-printed areas in the coordinates specified by the color system * abThe upper limit of the content of the colorant (I) in the thermosetting film for forming a protective film is not particularly limited as long as a film for forming a protective film satisfying the above can be obtained, but is preferably 0.2 mass% or more, more preferably 0.5 mass% or more, and even more preferably 1.5 mass% or more, based on the total content (total mass) of all components other than the solvent. The upper limit of the content of the colorant (I) in the thermosetting film for forming a protective film is not particularly limited, but is preferably 10 mass% or less, and can be 5 mass% or less, based on the total content (total mass) of all components other than the solvent, from the viewpoint of suppressing an excessive decrease in the light transmittance of the thermosetting film for forming a protective film.

[0146] [General Purpose Additives (J)] The composition for forming a protective film (1) and the thermosetting film for forming a protective film may contain a general-purpose additive (J) within the range that does not impair the effects of the present invention.

[0147] The general-purpose additive (J) may be a known one and may be arbitrarily selected depending on the purpose, and is not particularly limited. Preferred ones include, for example, plasticizers, antistatic agents, antioxidants, gettering agents, and the like.

[0148] The composition for a film for forming a protective film (1) and the thermosetting film for forming a protective film may contain only one type of general-purpose additive (J), or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0149] The content of the composition for forming a protective film (1) and the general-purpose additive (J) in the thermosetting film for forming a protective film is not particularly limited and may be appropriately selected depending on the purpose.

[0150] [Solvent (K)] The composition for forming a protective film (1) preferably further contains a solvent (K). The composition for forming a protective film (1) containing the solvent (K) has good handleability.

[0151] The above-mentioned solvent (K) is not particularly limited, but preferred examples thereof include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol), and 1-butanol; esters such as ethyl acetate and butyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; and amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.

[0152] The solvent (K) contained in the composition for forming a protective film (1) may be one type or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0153] The solvent (K) contained in the composition for forming a protective film (1) is preferably methyl ethyl ketone or the like, since the components contained in the composition for forming a protective film (1) can be mixed more uniformly.

[0154] The content of the solvent is preferably an amount such that the solids concentration of the composition for forming a film for a protective film is 10 to 80 mass %, more preferably an amount such that the solids concentration of the composition for forming a film for a protective film is 20 to 70 mass %, and even more preferably an amount such that the solids concentration of the composition for forming a film for a protective film is 30 to 65 mass %, relative to the total mass of the composition for forming a film for a protective film.

[0155] <<Production method of composition for forming thermosetting protective film>> The thermosetting composition for forming a film for forming a protective film, which is the composition for forming a protective film (1), can be obtained by blending the respective components for constituting the composition.

[0156] The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously.

[0157] When a solvent is used, the solvent may be used by mixing it with any of the other ingredients to pre-dilute the ingredients, or the solvent may be used by mixing it with any of the other ingredients without pre-diluting the ingredients.

[0158] The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, a method of mixing by adding ultrasound, etc.

[0159] The temperature and time during addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0160] Energy ray curable protective film The energy ray-curable protective film-forming film contains an energy ray-curable component (a).

[0161] The energy ray-curable component (a) is preferably uncured and preferably has adhesive properties, and more preferably is uncured and has adhesive properties.

[0162] In this specification, the term "energy rays" refers to electromagnetic waves or charged particle beams having an energy quantum, examples of which include ultraviolet rays and electron beams. Ultraviolet rays can be irradiated by using, for example, a high-pressure mercury lamp, a fusion lamp, a xenon lamp, or the like as an ultraviolet ray source. Electron beams can be irradiated by generating them using an electron beam accelerator, or the like.

[0163] In this specification, the term "energy ray curable" means a property of being cured by irradiation with energy rays, and the term "non-energy ray curable" means a property of not being cured even when irradiated with energy rays.

[0164] <<Energy ray curable protective film forming composition>> The energy ray curable protective film forming film can be formed from a composition for forming an energy ray curable protective film containing its constituent materials. For example, the composition for forming an energy ray curable protective film is applied to the surface of the energy ray curable protective film forming film to be formed, and dried as necessary, to form the energy ray curable protective film forming film at the desired location. The content ratio of the components that do not vaporize at room temperature in the composition for forming an energy ray curable protective film is usually the same as the content ratio of the components in the energy ray curable protective film forming film. Here, "room temperature" is as explained above.

[0165] The energy ray-curable protective film-forming composition may be applied by a known method, and examples of the method include methods using various coaters such as an air knife coater, a blade coater, a bar coater, a gravure coater, a roll coater, a roll knife coater, a curtain coater, a die coater, a knife coater, a screen coater, a Mayer bar coater, and a kiss coater.

[0166] The drying conditions for the energy ray-curable composition for forming a protective film are not particularly limited. When the composition for forming an energy ray-curable protective film contains a solvent described below, it is preferable to heat-dry it. In this case, it is preferable to dry it under conditions of, for example, 70 to 130° C. for 10 seconds to 5 minutes.

[0167] <Composition for forming protective film (2)> Examples of the energy ray-curable protective film-forming composition include: the below described Examples thereof include an energy ray-curable composition for forming a protective film (2) (sometimes referred to simply as “composition for forming a protective film (2)” in this specification) containing an energy ray-curable component (a).

[0168] [Energy ray curable component (a)] The energy ray-curable component (a) is a component that is cured by irradiation with energy rays, and is also a component that imparts film-forming properties, flexibility, and the like to the energy ray-curable protective film-forming film.

[0169] Examples of the energy ray curable component (a) include a polymer (a1) having an energy ray curable group and a weight average molecular weight of 80000 to 2000000, and a compound (a2) having an energy ray curable group and a molecular weight of 100 to 80000. The polymer (a1) may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

[0170] (Polymer (a1) having an energy ray-curable group and a weight average molecular weight of 80,000 to 2,000,000) An example of the polymer (a1) having an energy ray-curable group and a weight average molecular weight of 80,000 to 2,000,000 includes an acrylic resin (a1-1) obtained by addition reaction of an acrylic polymer (a11) having a functional group capable of reacting with a group possessed by another compound with an energy ray-curable compound (a12) having a group reactive with the functional group and an energy ray-curable group such as an energy ray-curable double bond.

[0171] Examples of the functional group in the acrylic polymer (a11) that can react with a group possessed by another compound include a hydroxyl group, a carboxy group, an amino group, a substituted amino group (a group in which one or two hydrogen atoms of an amino group are substituted with a group other than a hydrogen atom), an epoxy group, etc. However, from the viewpoint of preventing corrosion of circuits such as semiconductor wafers and semiconductor chips, the functional group is preferably a group other than a carboxy group. Of these, the functional group is preferably a hydroxyl group.

[0172] Acrylic polymer having functional groups (a11) The acrylic polymer (a11) having a functional group may be, for example, a polymer obtained by copolymerizing an acrylic monomer having the above-mentioned functional group with an acrylic monomer not having the above-mentioned functional group. In addition to these monomers, a monomer other than the acrylic monomer (non-acrylic monomer) may also be copolymerized.

[0173] The acrylic polymer (a11) may be a random copolymer or a block copolymer.

[0174] Examples of the acrylic monomer having a functional group include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, a substituted amino group-containing monomer, and an epoxy group-containing monomer.

[0175] Examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and non-(meth)acrylic unsaturated alcohols (i.e., unsaturated alcohols not having a (meth)acryloyl skeleton) such as vinyl alcohol and allyl alcohol.

[0176] Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids (i.e., monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (i.e., dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid and citraconic acid; anhydrides of the above ethylenically unsaturated dicarboxylic acids; and (meth)acrylic acid carboxyalkyl esters such as 2-carboxyethyl methacrylate.

[0177] The acrylic monomer having a functional group is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer, more preferably a hydroxyl group-containing monomer.

[0178] In this specification, the term "(meth)acrylic acid" is a concept that includes both "acrylic acid" and "methacrylic acid." The same applies to terms similar to (meth)acrylic acid. For example, "(meth)acrylate" is a concept that includes both "acrylate" and "methacrylate," and "(meth)acryloyl group" is a concept that includes both "acryloyl group" and "methacryloyl group."

[0179] The acrylic monomer having a functional group that constitutes the acrylic polymer (a11) may be of only one type, or of two or more types. When two or more types are used, the combination and ratio thereof can be selected arbitrarily.

[0180] The acrylic monomer not having a functional group is preferably a (meth)acrylic acid alkyl ester in which the alkyl group constituting the alkyl ester has a chain structure having 1 to 18 carbon atoms, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and ethyl (meth)acrylate. Examples of such acrylates include isooctyl acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (also referred to as lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (also referred to as palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (also referred to as stearyl (meth)acrylate).

[0181] Examples of acrylic monomers not having the above-mentioned functional group include alkoxyalkyl group-containing (meth)acrylic acid esters such as methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate; (meth)acrylic acid esters having an aromatic group, including (meth)acrylic acid aryl esters such as phenyl (meth)acrylate; non-crosslinkable (meth)acrylamide and derivatives thereof; and (meth)acrylic acid esters having a non-crosslinkable tertiary amino group, such as N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

[0182] The acrylic monomer not having a functional group constituting the acrylic polymer (a11) may be of only one type or of two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0183] Examples of the non-acrylic monomer include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0184] The non-acrylic monomer constituting the acrylic polymer (a11) may be of only one kind, or of two or more kinds. When two or more kinds are used, the combination and ratio thereof can be selected arbitrarily.

[0185] In the acrylic polymer (a11), the proportion (content) of the structural unit derived from the acrylic monomer having the functional group is preferably 0.1 to 50 mass%, more preferably 1 to 40 mass%, and particularly preferably 3 to 30 mass%, based on the total mass of the structural units constituting the acrylic polymer (a11). When the proportion is within such a range, the degree of curing of the protective film can be easily adjusted to a preferred range by the content of the energy ray-curable group in the acrylic resin (a1-1) obtained by copolymerization of the acrylic polymer (a11) and the energy ray-curable compound (a12).

[0186] The acrylic polymer (a11) constituting the acrylic resin (a1-1) may be of one type or of two or more types, and when there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0187] Energy ray curable compounds (a12) The energy ray curable compound (a12) preferably has one or more groups selected from the group consisting of an isocyanate group, an epoxy group, and a carboxy group as a group capable of reacting with the functional group of the acrylic polymer (a11), and more preferably has an isocyanate group as the group. For example, when the energy ray curable compound (a12) has an isocyanate group as the group, the isocyanate group easily reacts with the hydroxyl group of the acrylic polymer (a11) having a hydroxyl group as the functional group.

[0188] The energy ray-curable compound (a12) preferably has 1 to 5, and more preferably 1 or 2, of the above energy ray-curable groups in one molecule.

[0189] Examples of the energy ray-curable compound (a12) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate; an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; Examples of the isocyanate include an acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or a polyisocyanate compound with a polyol compound and hydroxyethyl (meth)acrylate.

[0190] Among these, the energy ray-curable compound (a12) is preferably 2-methacryloyloxyethyl isocyanate.

[0191] The energy ray-curable compound (a12) constituting the acrylic resin (a1-1) may be of only one type, or of two or more types. When two or more types are used, the combination and ratio thereof can be selected arbitrarily.

[0192] The content of the acrylic resin (a1-1) is preferably 1 to 40 mass %, more preferably 2 to 30 mass %, and particularly preferably 3 to 20 mass %, based on the total mass of the components other than the solvent of the composition for forming a protective film (2).

[0193] In the acrylic resin (a1-1), the content ratio of the energy ray curable group derived from the energy ray curable compound (a12) to the content of the functional group derived from the acrylic polymer (a11) is preferably 20 to 120 mol%, more preferably 35 to 100 mol%, and particularly preferably 50 to 100 mol%. When the content ratio is in such a range, the adhesive strength of the protective film after curing is increased. When the energy ray curable compound (a12) is a monofunctional compound (having one of the above groups in one molecule), the upper limit of the content ratio is 100 mol%, but when the energy ray curable compound (a12) is a polyfunctional compound (having two or more of the above groups in one molecule), the upper limit of the content ratio may exceed 100 mol%. Here, "derived from" means that the chemical structure changes due to polymerization.

[0194] The weight average molecular weight (Mw) of the polymer (a1) is preferably from 100,000 to 2,000,000, and more preferably from 300,000 to 1,500,000. The "weight average molecular weight" here is as explained above.

[0195] When the polymer (a1) is at least partially crosslinked with a crosslinking agent, the polymer (a1) may be crosslinked at the group reactive with the crosslinking agent by polymerization of a monomer which does not correspond to any of the above-mentioned monomers described as constituting the acrylic polymer (a11) and has a group reactive with the crosslinking agent, or the polymer (a1) may be crosslinked at a group reactive with the functional group derived from the energy ray-curable compound (a12).

[0196] The polymer (a1) contained in the composition for forming a protective film (2) and the energy ray curable film for forming a protective film may be one type or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0197] (Compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80,000) The energy ray-curable group contained in the compound (a2) having an energy ray-curable group and a molecular weight of 100 to 80,000 includes a group containing an energy ray-curable double bond, and preferred examples thereof include a (meth)acryloyl group and a vinyl group.

[0198] The compound (a2) is not particularly limited as long as it satisfies the above conditions, and examples of the compound (a2) include a low molecular weight compound having an energy ray-curable group, an epoxy resin having an energy ray-curable group, and a phenol resin having an energy ray-curable group.

[0199] Among the compounds (a2), examples of the low molecular weight compound having an energy ray-curable group include polyfunctional monomers or oligomers, and acrylate compounds having a (meth)acryloyl group are preferred.

[0200] Examples of the acrylate compounds include 2-hydroxy-3-(meth)acryloyloxypropyl methacrylate, polyethylene glycol di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxypolyethoxy)phenyl]propane, ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-((meth)acryloxydiethoxy)phenyl]propane, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, 2,2-bis[4-((meth)acryloxypolypropoxy)phenyl]propane, tricyclodecane dimethanol di(meth)acrylate, 1,10-decane diol di(meth)acrylate, 1,2-dimethylphenyl dimethacrylate, 1,3-dimethylphenyl dimethacrylate, 1,4-dimethylphenyl dimethacrylate, 1,5-dimethylphenyl dimethacrylate, 1,6-dimethylphenyl dimethacrylate, 1,7-dimethylphenyl dimethacrylate, 1,8-dimethylphenyl dimethacrylate, 1,9-dimethylphenyl dimethacrylate, 1,10-dimethylphenyl dimeth ... bifunctional (meth)acrylates such as 6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 2,2-bis[4-((meth)acryloxyethoxy)phenyl]propane, neopentyl glycol di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, and 2-hydroxy-1,3-di(meth)acryloxypropane; polyfunctional (meth)acrylates such as tris(2-(meth)acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, ethoxylated glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; Examples of the polyfunctional (meth)acrylate oligomer include urethane (meth)acrylate oligomer.

[0201] Among the compounds (a2), examples of the epoxy resin having an energy ray curable group and the phenolic resin having an energy ray curable group that can be used include those described in paragraph 0043 of JP 2013-194102 A. Although such resins also fall under the category of resins constituting the thermosetting component described below, in the present invention they are treated as the compound (a2).

[0202] The compound (a2) has a weight average molecular weight of preferably 100 to 30,000, and more preferably 300 to 10,000.

[0203] The compound (a2) contained in the composition for forming a protective film (2) and the energy ray curable film for forming a protective film may be one type or two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0204] [Polymer (b) having no energy ray-curable group] When the composition for forming a protective film (2) and the energy ray-curable film for forming a protective film contain the above-mentioned compound (a2) as the above-mentioned energy ray-curable component (a), it is preferable that they also contain a polymer (b) that does not have an energy ray-curable group. The polymer (b) may be at least partially crosslinked with a crosslinking agent, or may not be crosslinked.

[0205] Examples of the polymer (b) having no energy ray-curable group include acrylic polymers, phenoxy resins, urethane resins, polyesters, rubber-based resins, and acrylic urethane resins.

[0206] Among these, the polymer (b) is preferably an acrylic polymer (hereinafter sometimes abbreviated as "acrylic polymer (b-1)").

[0207] The acrylic polymer (b-1) may be a known one, and may be, for example, a homopolymer of one kind of acrylic monomer, a copolymer of two or more kinds of acrylic monomers, or a copolymer of one or more kinds of acrylic monomers and one or more kinds of monomers other than the acrylic monomers (non-acrylic monomers).

[0208] Examples of the acrylic monomer constituting the acrylic polymer (b-1) include (meth)acrylic acid alkyl esters, (meth)acrylic acid esters having a cyclic skeleton, glycidyl group-containing (meth)acrylic acid esters, hydroxyl group-containing (meth)acrylic acid esters, substituted amino group-containing (meth)acrylic acid esters, etc. Here, the "substituted amino group" is as explained above.

[0209] The (meth)acrylic acid alkyl ester is preferably a (meth)acrylic acid alkyl ester in which the alkyl group constituting the alkyl ester has a chain structure having 1 to 18 carbon atoms, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and ethyl (meth)acrylate. Examples of such acrylates include isooctyl acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (also called lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate (also called myristyl (meth)acrylate), pentadecyl (meth)acrylate, hexadecyl (meth)acrylate (also called palmityl (meth)acrylate), heptadecyl (meth)acrylate, and octadecyl (meth)acrylate (stearyl (meth)acrylate).

[0210] Examples of the (meth)acrylic acid ester having a cyclic skeleton include cycloalkyl (meth)acrylic acid esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester; (Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester are included. The glycidyl group-containing (meth)acrylic acid ester may, for example, be glycidyl (meth)acrylate. Examples of the hydroxyl group-containing (meth)acrylic acid ester include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0211] The substituted amino group-containing (meth)acrylic acid ester may, for example, be N-methylaminoethyl (meth)acrylate.

[0212] Examples of the non-acrylic monomer constituting the acrylic polymer (b-1) include olefins such as ethylene and norbornene; vinyl acetate; and styrene.

[0213] The polymer (b) having no energy ray-curable group and at least a portion of which is crosslinked with a crosslinking agent may be, for example, one in which a reactive functional group in the polymer (b) has reacted with a crosslinking agent.

[0214] The reactive functional group may be appropriately selected according to the type of crosslinking agent, and is not particularly limited. For example, when the crosslinking agent is a polyisocyanate compound, the reactive functional group may be a hydroxyl group, a carboxyl group, an amino group, etc., and among these, a hydroxyl group having high reactivity with an isocyanate group is preferred. When the crosslinking agent is an epoxy compound, the reactive functional group may be a carboxyl group, an amino group, an amide group, etc., and among these, a carboxyl group having high reactivity with an epoxy group is preferred. However, from the viewpoint of preventing corrosion of the circuit of a semiconductor wafer or a semiconductor chip, the reactive functional group is preferably a group other than a carboxyl group.

[0215] The polymer (b) having the reactive functional group and not having an energy ray curable group may be, for example, one obtained by polymerizing at least a monomer having the reactive functional group. In the case of the acrylic polymer (b-1), one or both of the acrylic monomer and the non-acrylic monomer listed as the monomers constituting the polymer may be one having the reactive functional group. For example, the polymer (b) having a hydroxyl group as a reactive functional group may be one obtained by polymerizing a hydroxyl group-containing (meth)acrylic acid ester, and other examples include one obtained by polymerizing a monomer in which one or more hydrogen atoms in the acrylic monomer or non-acrylic monomer listed above are substituted with the reactive functional group.

[0216] In the polymer (b) having a reactive functional group, the proportion (content) of the structural unit derived from the monomer having a reactive functional group is preferably 1 to 20 mass% and more preferably 2 to 10 mass% based on the total mass of the structural units constituting the polymer (b). When the proportion is in this range, the degree of crosslinking in the polymer (b) becomes a more preferable range.

[0217] The weight average molecular weight (Mw) of the polymer (b) having no energy ray-curable group is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000, in order to improve the film-forming property of the composition for forming a protective film (2). Here, the "weight average molecular weight" is as explained above.

[0218] The composition for a film for forming a protective film (2) and the energy ray-curable film for forming a protective film contain only one type of polymer (b) that does not have an energy ray-curable group, and may contain two or more types. When there are two or more types, the combination and ratio thereof can be selected arbitrarily.

[0219] The composition for forming a protective film (2) may contain either one or both of the polymer (a1) and the compound (a2). When the composition for forming a protective film (2) contains the compound (a2), it is preferable that the composition for forming a protective film (2) further contains a polymer (b) having no energy ray curable group. In this case, the composition for forming a protective film (2) further contains the polymer (b) having no energy ray curable group. Polymer It is also preferable that the composition for forming a protective film (2) contains both the polymer (a1) and the polymer (b) having no energy ray curable group without containing the compound (a2).

[0220] When the composition for a film for forming a protective film (2) contains the above polymer (a1), the above compound (a2), and the polymer (b) not having an energy ray-curable group, the content of the above compound (a2) in the composition for a film for forming a protective film (2) is preferably 10 to 400 parts by mass, and more preferably 30 to 350 parts by mass, per 100 parts by mass of the total content of the above polymer (a1) and the polymer (b) not having an energy ray-curable group.

[0221] In the composition for a protective film (2), the total content of the energy ray curable component (a) and the polymer (b) having no energy ray curable group relative to the total content (total mass) of components other than the solvent (i.e., the total content of the energy ray curable component (a) and the polymer (b) having no energy ray curable group in the energy ray curable protective film-forming film) is preferably 5 to 90 mass%, more preferably 10 to 80 mass%, and particularly preferably 20 to 70 mass%. When the content ratio of the energy ray curable component is within such a range, the energy ray curability of the energy ray curable protective film-forming film becomes better.

[0222] The content of the energy ray curable component (a) is preferably 1 to 80% by mass based on the total mass of the components other than the solvent in the composition for forming a protective film (2).

[0223] The content of the energy ray curable component (a1) is preferably 1 to 80 mass % based on the total mass of the components other than the solvent in the composition for forming a protective film (2).

[0224] The content of the energy ray curable component (a2) is preferably 1 to 80% by mass based on the total mass of the components other than the solvent in the composition for forming a protective film (2).

[0225] The content of the polymer (b) having no energy ray-curable group is preferably 1 to 80% by mass based on the total mass of the components other than the solvent in the composition for forming a protective film (2).

[0226] The total content of the above components (a1), (a2) and (b) does not exceed 100% by mass.

[0227] In addition to the energy ray curable component, the composition for a film for forming a protective film (2) may further contain one or more selected from the group consisting of a thermosetting component, a photopolymerization initiator, a filler, a coupling agent, a crosslinking agent, a colorant, and a general-purpose additive, depending on the purpose. For example, by using the composition for a film for forming a protective film (2) containing the energy ray curable component and the thermosetting component, the adhesive strength of the energy ray curable film for forming a protective film formed using the composition for forming a protective film (2) for forming a protective film to an adherend is improved by heating, and the strength of the protective film formed from the energy ray curable film for forming a protective film is also improved.

[0228] The above-mentioned thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, colorant and general-purpose additive in the composition for a film for forming a protective film (2) may be the same as the thermosetting component (B), photopolymerization initiator (H), filler (D), coupling agent (E), crosslinking agent (F), colorant (I) and general-purpose additive (J) in the composition for a film for forming a protective film (1).

[0229] In the composition for forming a protective film (2), the above-mentioned thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, colorant and general-purpose additive may each be used alone or in combination of two or more kinds. When two or more kinds are used in combination, the combination and ratio thereof can be selected arbitrarily.

[0230] The contents of the above-mentioned thermosetting component, photopolymerization initiator, filler, coupling agent, crosslinking agent, colorant and general-purpose additive in the composition for protective film formation (2) may be appropriately adjusted depending on the purpose, and are not particularly limited.

[0231] The composition for forming a protective film (2) preferably further contains a solvent, since dilution improves its handling properties.

[0232] Examples of the solvent contained in the composition for forming a protective film (2) include the same solvents as those in the composition for forming a protective film (1).

[0233] The composition for forming a protective film (2) may contain only one type of solvent, or two or more types of solvents.

[0234] <<Method of manufacturing a composition for forming an energy ray-curable protective film>> The energy ray-curable composition for forming a film for forming a protective film, such as the composition for forming a film for forming a protective film (2), can be obtained by blending the respective components for constituting the composition.

[0235] The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously.

[0236] When a solvent is used, the solvent may be used by mixing it with any of the other ingredients to pre-dilute the ingredients, or the solvent may be used by mixing it with any of the other ingredients without pre-diluting the ingredients.

[0237] The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, a method of mixing by adding ultrasound, etc.

[0238] The temperature and time during addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0239] Color control of protective film The protective film has a color difference ΔE between the printed and non-printed areas. * ab The composition is not particularly limited as long as the color difference ΔE between the printed and non-printed areas is 8 or more. The film for forming a protective film contains the above-mentioned various resin components, additives such as a curing agent, a colorant (I), and a filler (D), and the color of the film for forming a protective film is determined by the types and blending ratios of these. * ab and the brightness difference ΔL *The difference in color tone between the printed area, where the surface roughness of the irradiated area has changed, or where the components of the irradiated area have changed in quality or evaporated, causing a change in the component ratio, and the non-printed area, where the laser light has not been irradiated, is measured according to CIE1976L. * a * b * It is a numerical representation of the color system.

[0240] In this specification, the color difference ΔE between the printed and non-printed areas * ab and the brightness difference ΔL * is calculated from the colors of the printed and non-printed areas when laser printing is performed under the conditions described in the Examples below. Color difference ΔE between printed and non-printed areas * ab and the brightness difference ΔL * is controlled by the types and blending ratios of the components constituting the protective film-forming film.

[0241] For example, by making the surface of the protective film darker before laser marking, the color difference ΔE * ab and the brightness difference ΔL * This is because the surface of the laser-printed area becomes rough, and the diffuse reflection increases the whiteness. Also, the color difference is more likely to be large by designing the area to have complementary color tones before and after laser printing, rather than using shades of the same color. Also, when using colorants that are easily vaporized by laser light irradiation, the amount of colorant in the printed area decreases, resulting in a different color tone from the non-printed area, and the color difference ΔE * ab and the brightness difference ΔL * becomes larger.

[0242] Protective film forming sheet The sheet for forming a protective film according to the present embodiment includes the above-mentioned film for forming a protective film and a support sheet described below. The film for forming a protective film may also include a release film on the side not including the support sheet.

[0243] After removing the release film, the protective film forming sheet according to this embodiment is attached to the surface (rear surface) of the semiconductor wafer opposite to the surface on which the circuit is provided by the protective film forming film. After this, at some stage, the protective film forming film is cured to form a protective film. Then, the laminate in which the support sheet, the protective film or the protective film forming film, and the semiconductor wafer are laminated in this order is further diced into individual laminates in which the support sheet, the protective film or the protective film forming film, and the semiconductor chip are laminated in this order. The semiconductor chip is finally picked up from the support sheet with the protective film on its rear surface. In this way, the protective film forming sheet according to this embodiment is used to form a protective film on the rear surface of the semiconductor chip.

[0244] In this specification, a sheet for forming a protective film in which a film for forming a protective film is cured by heating or irradiation with energy rays to form a protective film is also called a sheet for forming a protective film, as long as the laminated structure of the support sheet and the protective film is maintained. In addition, in a sheet for forming a protective film, for example, when the support sheet has an adhesive layer, a sheet obtained by curing this adhesive layer is also called a sheet for forming a protective film, as long as the laminated structure of the cured product of the adhesive layer and the film for forming a protective film or the protective film is maintained.

[0245] Examples of the support sheet include those having a substrate, and examples of such support sheets include a sheet consisting of only the substrate and a sheet having other layers, such as an adhesive layer, an intermediate layer, a coating layer, etc., laminated on the substrate. The other layer may be only one layer (single layer) or may be two or more layers. When there are multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited. In this specification, not limited to the case of the other layers described above, "multiple layers may be the same or different from each other" means "all layers may be the same, all layers may be different, or only some layers may be the same", and further, "multiple layers are different from each other" means "at least one of the material and thickness of each layer is different from each other".

[0246] Thus, in this embodiment, various types of sheets can be used as the support sheet. Below, the protective film forming sheet according to this embodiment will be described for each type of support sheet. Note that, in the drawings used in the following description, for the sake of convenience, the main parts may be enlarged in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0247] FIG. 1 is a cross-sectional view that illustrates one embodiment of the sheet for forming a protective film according to the present embodiment.

[0248] 1 includes a pressure-sensitive adhesive layer 12 on a substrate 11, and a film 13 for forming a protective film on the pressure-sensitive adhesive layer 12. The support sheet 10 is a laminate of the substrate 11 and the pressure-sensitive adhesive layer 12, and the sheet 1A for forming a protective film has a configuration in which the film 13 for forming a protective film is laminated on one surface 10a of the support sheet 10. The sheet 1A for forming a protective film further includes a release film 15 on the film 13 for forming a protective film.

[0249] In the sheet 1A for forming a protective film, an adhesive layer 12 is laminated on one surface 11a of a substrate 11, a film 13 for forming a protective film is laminated on the entire surface 12a of the adhesive layer 12 (the surface opposite to the surface of the adhesive layer 12 that contacts the substrate 11), a jig adhesive layer 16 is laminated on a portion of the surface 13a of the film 13 for forming a protective film (the surface opposite to the surface of the film 13 for forming a protective film that contacts the adhesive layer 12), and a release film 15 is laminated on the surface of the surface 13a of the film 13 for forming a protective film on which the jig adhesive layer 16 is not laminated and on the surface 16a of the jig adhesive layer 16 (the upper surface, i.e., the surface opposite to the surface of the jig adhesive layer 16 that contacts the film 13 for forming a protective film, and the side surface).

[0250] The jig adhesive layer 16 may be, for example, a single-layer structure containing an adhesive component, or a multi-layer structure in which layers containing adhesive components are laminated on both sides of a core sheet.

[0251] The protective film forming sheet 1A shown in Figure 1 is used by attaching the back surface of a semiconductor wafer (not shown) to the surface 13a of the protective film forming film 13 with the release film 15 removed, and further attaching the upper surface of the surface 16a of the jig adhesive layer 16 to a jig such as a ring frame.

[0252] Fig. 2 is a cross-sectional view showing a schematic diagram of another embodiment of the sheet for forming a protective film according to the present embodiment. In Fig. 2, the same components as those shown in Fig. 1 are given the same reference numerals as in Fig. 1, and detailed explanations thereof are omitted. This also applies to Fig. 3 and subsequent figures.

[0253] The sheet for forming a protective film 1B shown in Fig. 2 is the same as the sheet for forming a protective film 1A shown in Fig. 1, except that it does not include the jig adhesive layer 16. That is, in the sheet for forming a protective film 1B, an adhesive layer 12 is laminated on one surface 11a of a substrate 11, a film for forming a protective film 13 is laminated on the entire surface 12a of the adhesive layer 12 (the surface opposite to the surface of the adhesive layer 12 that contacts the substrate 11), and a release film 15 is laminated on the entire surface 13a of the film for forming a protective film 13 (the surface opposite to the surface of the film for forming a protective film 13 that contacts the adhesive layer 12).

[0254] The protective film forming sheet 1B shown in Figure 2 has the release film 15 removed, and the back surface of a semiconductor wafer (not shown) is attached to a portion of the central area of ​​the surface 13a of the protective film forming film 13, and further, an area of ​​the protective film forming film 13 near the peripheral portion surrounding the semiconductor wafer is attached to a jig such as a ring frame for use.

[0255] FIG. 3 is a cross-sectional view that illustrates a schematic diagram of still another embodiment of the sheet for forming a protective film according to the present embodiment.

[0256] The sheet 1C for forming a protective film shown in FIG. 3 is the same as the sheet 1A for forming a protective film shown in FIG. 1, except that it does not have the adhesive layer 12. That is, in the sheet 1C for forming a protective film, the support sheet 10 is made of only a substrate 11. A film 13 for forming a protective film is laminated on one surface 11a of the substrate 11, a jig adhesive layer 16 is laminated on a part of the surface 13a (the surface opposite to the surface of the film 13 for forming a protective film that contacts the substrate) of the film 13 for forming a protective film, and a release film 15 is laminated on the surface of the film 13 for forming a protective film on which the jig adhesive layer 16 is not laminated and on the surface 16a of the jig adhesive layer 16 (the upper surface, i.e., the surface opposite to the surface of the film 13 for forming a protective film in the jig adhesive layer 16 that contacts the film 13 for forming a protective film, and the side surface).

[0257] The protective film forming sheet 1C shown in Figure 3, like the protective film forming sheet 1A shown in Figure 1, is used by attaching the back surface of a semiconductor wafer (not shown) to the surface 13a of the protective film forming film 13 with the release film 15 removed, and further attaching the upper surface of the surface 16a of the jig adhesive layer 16 to a jig such as a ring frame.

[0258] FIG. 4 is a cross-sectional view that illustrates a schematic diagram of still another embodiment of the sheet for forming a protective film according to the present embodiment.

[0259] The sheet for forming a protective film 1D shown in Fig. 4 is the same as the sheet for forming a protective film 1C shown in Fig. 3, except that it does not include the jig adhesive layer 16. That is, in the sheet for forming a protective film 1D, a film for forming a protective film 13 is laminated on one surface 11a of the substrate 11, and a release film 15 is laminated on the entire surface 13a of the film for forming a protective film 13 (the surface of the film for forming a protective film 13 opposite to the surface that contacts the substrate).

[0260] As with the protective film forming sheet 1B shown in FIG. 2, the protective film forming sheet 1D shown in FIG. 4 has the release film 15 removed, and is used by attaching the back surface of a semiconductor wafer (not shown) to a portion of the central area of ​​the surface 13a of the protective film forming film 13, and further attaching an area of ​​the protective film forming film 13 near the peripheral portion surrounding the semiconductor wafer to a jig such as a ring frame.

[0261] FIG. 5 is a cross-sectional view that illustrates a schematic diagram of still another embodiment of the sheet for forming a protective film according to the present embodiment.

[0262] The protective film-forming sheet 1E shown in Figure 5 is the same as the protective film-forming sheet 1A shown in Figure 1, except that it has a coating layer 14 on the surface 11b of the substrate 11 opposite the side having the adhesive layer 12 (hereinafter sometimes referred to as the back surface of the substrate).

[0263] That is, in the sheet 1E for forming a protective film, the support sheet 10 is a laminate in which a coating layer 14, a base material 11 and an adhesive layer 12 are laminated in this order, and the sheet 1E for forming a protective film has a configuration in which a film 13 for forming a protective film is laminated on one surface 10a of the support sheet 10. An adhesive layer 12 is laminated on one surface 11a of the substrate 11, a protective film-forming film 13 is laminated on the entire surface 12a of the adhesive layer 12 (the surface opposite to the surface of the adhesive layer 12 that contacts the substrate 11), a jig adhesive layer 16 is laminated on a portion of the surface 13a of the protective film-forming film 13 (the surface opposite to the surface of the protective film-forming film 13 that contacts the adhesive layer 12), and a release film 15 is laminated on the surface of the surface 13a of the protective film-forming film 13 on which the jig adhesive layer 16 is not laminated and on the surface 16a of the jig adhesive layer 16 (the upper surface, i.e., the surface opposite to the surface of the jig adhesive layer 16 that contacts the protective film-forming film 13, and the side surface).

[0264] The protective film forming sheet 1E shown in Figure 5, like the protective film forming sheet 1A shown in Figure 1, is used by attaching the back surface of a semiconductor wafer (not shown) to the surface 13a of the protective film forming film 13 with the release film 15 removed, and further attaching the upper surface of the surface 16a of the jig adhesive layer 16 to a jig such as a ring frame.

[0265] FIG. 6 is a cross-sectional view that illustrates a schematic diagram of still another embodiment of the sheet for forming a protective film according to the present embodiment.

[0266] The sheet 1F for forming a protective film shown here is the same as the sheet 1E for forming a protective film shown in FIG. 5, except that it does not have a jig adhesive layer 16. That is, in the sheet 1F for forming a protective film, an adhesive layer 12 is laminated on one surface 11a of the substrate 11, a film for forming a protective film 13 is laminated on the entire surface 12a (the surface of the adhesive layer 12 opposite to the surface that contacts the substrate 11) of the adhesive layer 12, and a release film 15 is laminated on the entire surface 13a (the surface of the film for forming a protective film opposite to the surface that contacts the adhesive layer 12) of the film for forming a protective film 13. In addition, the back surface 11b of the film for forming a protective film (the surface of the film for forming a protective film opposite to the surface that contacts the adhesive layer 12) of the substrate 11 is the same as that of the sheet 1E for forming a protective film shown in FIG. 5, and a coating layer 14 is laminated thereon.

[0267] As with the protective film forming sheet 1B shown in FIG. 2, the protective film forming sheet 1F shown in FIG. 6 has the release film 15 removed, and the back surface of a semiconductor wafer (not shown) is attached to a central area of ​​the surface 13a of the protective film forming film 13, and further, an area of ​​the protective film forming film 13 near the peripheral portion surrounding the semiconductor wafer is attached to a jig such as a ring frame for use.

[0268] FIG. 7 is a cross-sectional view that illustrates a schematic diagram of still another embodiment of the sheet for forming a protective film according to the present embodiment.

[0269] The sheet for forming a protective film 1G shown here is the same as the sheet for forming a protective film 1A shown in FIG. 1, except that the shape of the film for forming a protective film is different. That is, the sheet for forming a protective film 1G comprises an adhesive layer 12 on a substrate 11, and a film for forming a protective film 23 on the adhesive layer 12. The support sheet 10 is a laminate of the substrate 11 and the adhesive layer 12, and the sheet for forming a protective film 1G has a configuration in which the film for forming a protective film 23 is laminated on one surface 10a of the support sheet 10. In addition, the sheet for forming a protective film 1G further comprises a release film 15 on the film for forming a protective film 23. The film for forming a protective film 23 is the same as the film for forming a protective film 13, except that the shape is different.

[0270] When the sheet 1G for forming a protective film is viewed from above in a plan view, the film 23 for forming a protective film has a smaller surface area than the pressure-sensitive adhesive layer 12 and has a shape such as a circle.

[0271] In the sheet 1G for forming a protective film, an adhesive layer 12 is laminated on one surface 11a of a substrate 11, and a film for forming a protective film 23 is laminated on a part of a surface 12a of the adhesive layer 12 (the surface of the adhesive layer 12 opposite to the surface that contacts the substrate 11). The surface 12a of the adhesive layer 12 on which the film for forming a protective film 23 is not laminated and the surface 23a (the upper surface, i.e., the surface of the film for forming a protective film 23) of the film for forming a protective film are laminated on the surface 12a of the adhesive layer 12 on which the film for forming a protective film is not laminated. sticky A release film 15 is laminated on the surface opposite to the surface in contact with the adhesive layer 12 and on the side surface.

[0272] The protective film forming sheet 1G shown in Figure 7 is used by attaching the back surface of a semiconductor wafer (not shown) to the surface 23a of the protective film forming film 23 with the release film 15 removed, and further attaching the surface of the surface 12a of the adhesive layer 12 on which the protective film forming film 23 is not laminated to a jig such as a ring frame.

[0273] FIG. 8 is a cross-sectional view that illustrates a schematic diagram of still another embodiment of the sheet for forming a protective film according to the present embodiment.

[0274] The sheet 1H for forming a protective film shown here is the same as the sheet 1G for forming a protective film shown in Fig. 7, except that it does not have an adhesive layer 12. That is, in the sheet 1H for forming a protective film, the support sheet is made of only a substrate 11. A film 23 for forming a protective film is laminated on a part of one surface 11a of the substrate 11, and a release film 15 is laminated on the surface of the surface 11a of the substrate 11 on which the film 23 for forming a protective film is not laminated, and on the surface 23a of the film 23 for forming a protective film (the upper surface, i.e., the surface opposite to the surface of the film 23 for forming a protective film that contacts the substrate 11, and the side surface).

[0275] 8, the back surface of a semiconductor wafer (not shown) is attached to the front surface 23a of the film 23 for forming a protective film with the release film 15 removed, and the surface of the front surface 11a of the base material 11 on which the film 23 for forming a protective film is not laminated is attached to a jig such as a ring frame by a jig adhesive layer (not shown) for use. As the jig adhesive layer, the same adhesive layer as the jig adhesive layer 16 shown in FIG. 1 etc. can be used.

[0276] In addition, the protective film formation sheet can be attached to a jig such as a ring frame by using the jig adhesive layer, regardless of the configuration of the support sheet.

[0277] The protective film forming sheet according to this embodiment is not limited to that shown in Figures 1 to 8, and may be one in which some of the configurations shown in Figures 1 to 8 have been changed or removed, or other configurations may be added to those described above, within the scope that does not impair the effects of the present invention.

[0278] 1, 2, 5, 6 and 7, the protective film-forming sheet is described as having a pressure-sensitive adhesive layer provided in direct contact with a substrate, but the protective film-forming sheet according to the present embodiment may have an intermediate layer provided between the substrate and the pressure-sensitive adhesive layer. That is, in the protective film-forming sheet according to the present embodiment, the support sheet may have a laminated structure in which the substrate, intermediate layer and pressure-sensitive adhesive layer are laminated in this order.

[0279] In Figures 3, 4 and 8, a sheet for forming a protective film has been described in which a film for forming a protective film is provided in direct contact with a substrate, but the sheet for forming a protective film in this embodiment may also be one in which an intermediate layer is provided between the substrate and the film for forming a protective film.

[0280] Any intermediate layer can be selected depending on the purpose, and a preferred intermediate layer is, for example, one that improves the adhesion between two adjacent layers.

[0281] Moreover, in the sheet for forming a protective film according to this embodiment, layers other than the intermediate layer may be provided at any positions.

[0282] Hereinafter, each component of the sheet for forming a protective film according to this embodiment will be described in more detail.

[0283] ○Support sheet In this embodiment, the support sheet constituting the sheet for forming a protective film is not particularly limited as long as it can be provided with the film for forming a protective film.Preferable support sheets include, for example, those consisting of only the substrate normally used in the field of semiconductor wafer processing sheets as described above, those consisting of a substrate and an adhesive layer laminated, those consisting of a coating layer and a substrate laminated, and those consisting of a coating layer, a substrate and an adhesive layer laminated in this order.Preferable support sheets include, for example, those consisting of a substrate, an intermediate layer and an adhesive layer laminated, and those having an intermediate layer between two adjacent layers in the laminate structure exemplified above.

[0284] That is, the support sheet may be made of one layer (single layer) or may be made of two or more layers. When the support sheet is made of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0285] The thickness of the support sheet may be appropriately selected depending on the purpose, but from the viewpoint of imparting sufficient flexibility to the protective film-forming sheet and enabling it to be easily attached to a semiconductor wafer, the thickness is preferably 10 to 500 μm, more preferably 20 to 350 μm, and even more preferably 30 to 200 μm.

[0286] Here, "thickness of the support sheet" means the total thickness of each layer constituting the support sheet; for example, in the case of a support sheet in which a base material and an adhesive layer are laminated, it means the total value of the thickness of the base material and the thickness of the adhesive layer.

[0287] In this specification, the term "thickness" refers to a value expressed as an average value of thicknesses measured at any five points using a contact thickness meter.

[0288] ·Base material In this embodiment, the material of the substrate constituting the support sheet is preferably various resins, and specific examples thereof include polyethylene (low density polyethylene, linear low density polyethylene, high density polyethylene, etc.), polypropylene, ethylene-propylene copolymer, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyurethane, polyurethane acrylate, polyimide, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, polystyrene, polycarbonate, fluororesin, water additives, modified products, crosslinked products or copolymers of any of these resins, and the like.

[0289] The thickness of the substrate can be appropriately selected depending on the purpose. When the support sheet is formed by laminating a substrate and other layers such as a pressure-sensitive adhesive layer, the thickness of the substrate is preferably 15 to 300 μm, more preferably 20 to 200 μm. When the thickness of the substrate is within such a range, the flexibility of the protective film-forming sheet and the attachability to a semiconductor wafer or semiconductor chip are further improved.

[0290] The substrate may be one layer (single layer) or two or more layers. When the substrate is made of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0291] When the substrate is made of a plurality of layers, the total thickness of the layers should be set to the above-mentioned preferable thickness of the substrate.

[0292] The substrate may be one that has been subjected to a surface treatment such as sandblasting, solvent treatment, embossing, etc. to make the substrate uneven (matte treatment), corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone / ultraviolet radiation treatment, flame treatment, chromate treatment, hot air treatment, etc., in order to improve adhesion to other layers such as a pressure-sensitive adhesive layer, a film for forming a protective film, a coating layer, etc. The substrate may be one that has been subjected to a primer treatment on the surface.

[0293] Adhesive layer In this embodiment, the pressure-sensitive adhesive layer constituting the support sheet can be any known pressure-sensitive adhesive layer.

[0294] The pressure-sensitive adhesive layer can be formed from a pressure-sensitive adhesive composition containing various components such as a pressure-sensitive adhesive to constitute the pressure-sensitive adhesive layer. The ratio of the contents of the components that do not vaporize at room temperature in the pressure-sensitive adhesive composition is usually the same as the ratio of the contents of the above-mentioned components in the pressure-sensitive adhesive layer. Here, "room temperature" is as described above.

[0295] The thickness of the pressure-sensitive adhesive layer can be appropriately selected depending on the purpose, but is preferably from 1 to 100 μm, more preferably from 2 to 80 μm, and even more preferably from 3 to 50 μm.

[0296] The pressure-sensitive adhesive layer may be one layer (single layer) or two or more layers. When the pressure-sensitive adhesive layer is made up of multiple layers, these multiple layers may be the same or different from each other, and the combination of these multiple layers is not particularly limited.

[0297] When the pressure-sensitive adhesive layer is made up of a plurality of layers, the total thickness of the layers should be adjusted to the above-mentioned preferred thickness of the pressure-sensitive adhesive layer.

[0298] Examples of the adhesive include adhesive resins such as acrylic resins, urethane resins, rubber resins, silicone resins, and vinyl ether resins. When attention is paid to the function of the resin, examples of the adhesive include energy ray curable resins.

[0299] Here, the terms "energy rays" and "energy ray-curable" are as explained above.

[0300] Examples of the energy ray-curable resin include those having a polymerizable group such as a (meth)acryloyl group or a vinyl group.

[0301] The adhesive resin is preferably an acrylic resin, and more preferably a (meth)acrylic acid ester copolymer containing a structural unit derived from a (meth)acrylic acid ester.

[0302] When the pressure-sensitive adhesive layer contains a component that polymerizes upon irradiation with energy rays, such as an energy-ray-curable resin, it becomes energy-ray-curable, and by irradiating it with energy rays to reduce its adhesiveness, it becomes easier to pick up the semiconductor chip with the protective film, which will be described later. Such a pressure-sensitive adhesive layer can be formed, for example, from various pressure-sensitive adhesive compositions that contain a component that polymerizes upon irradiation with energy rays.

[0303] <<Adhesive composition>> Preferred among the above-mentioned pressure-sensitive adhesive compositions are those containing a component that polymerizes upon irradiation with energy rays. Examples of such pressure-sensitive adhesive compositions include those containing an acrylic resin and an energy ray-polymerizable compound (hereinafter, sometimes abbreviated as "pressure-sensitive adhesive composition (i)"); those containing the above-mentioned acrylic resin having a hydroxyl group and a polymerizable group on the side chain (for example, one having a hydroxyl group and a polymerizable group on the side chain via a urethane bond) and an isocyanate-based crosslinking agent (hereinafter, sometimes abbreviated as "pressure-sensitive adhesive composition (ii)"); and the like.

[0304] [Adhesive composition (i)] The pressure-sensitive adhesive composition (i) contains the above-mentioned acrylic resin and an energy ray-polymerizable compound as essential components. Each component will be described below.

[0305] (Acrylic resin) A preferred example of the acrylic resin in the pressure-sensitive adhesive composition (i) is a (meth)acrylic acid ester copolymer obtained by polymerizing a (meth)acrylic acid ester as a monomer and, if necessary, a monomer other than a (meth)acrylic acid ester.

[0306] Examples of the (meth)acrylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, lauryl (meth)acrylate, and the like. (meth)acrylic acid alkyl esters in which the alkyl group constituting the alkyl ester has a chain structure having 1 to 18 carbon atoms, such as (meth)acrylic acid alkyl esters ... (meth)acrylic acid cycloalkyl esters such as isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate; (Meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (Meth)acrylic acid cycloalkenyl esters such as (meth)acrylic acid dicyclopentenyl ester; (Meth)acrylic acid cycloalkenyloxyalkyl esters such as (meth)acrylic acid dicyclopentenyloxyethyl ester; (Meth)acrylic acid imide; glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate; Examples of hydroxyl group-containing (meth)acrylic acid esters include hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0307] Of the above, methyl methacrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and the like are preferred.

[0308] Examples of the monomer other than the (meth)acrylic acid ester include (meth)acrylic acid, itaconic acid, vinyl acetate, acrylonitrile, styrene, and N-methylolacrylamide.

[0309] The various monomers constituting the acrylic resin, such as the (meth)acrylic acid ester and the monomer other than the (meth)acrylic acid ester, may each be of one type or two or more types.

[0310] The pressure-sensitive adhesive composition (i) may contain only one type of acrylic resin, or two or more types of acrylic resins.

[0311] The content of the acrylic resin in the pressure-sensitive adhesive composition (i) is preferably 40 to 99 mass % based on the total mass of all components contained in the pressure-sensitive adhesive composition (i) other than the solvent, and more preferably 50 to 91 mass %. mass % is more preferable.

[0312] (Energy ray polymerizable compound) The energy ray-polymerizable compound in the pressure-sensitive adhesive composition (i) is a compound that is polymerized and cured by irradiation with energy rays, and examples thereof include compounds having an energy ray-polymerizable group such as an energy ray-curable double bond in the molecule.

[0313] Examples of the energy ray-polymerizable compound include low molecular weight compounds (monofunctional or polyfunctional monomers and oligomers) having an energy ray-polymerizable group, more specifically, (meth)acrylates such as trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate; (meth)acrylates containing a cyclic aliphatic skeleton, such as dicyclopentadiene dimethoxydi(meth)acrylate; Examples of the (meth)acrylate compounds include polyethylene glycol di(meth)acrylate, oligoester (meth)acrylate, urethane (meth)acrylate oligomer, epoxy modified (meth)acrylate, polyether (meth)acrylate, and itaconic acid oligomer.

[0314] The energy ray-polymerizable compound preferably has a molecular weight of 100 to 30,000, and more preferably 300 to 10,000.

[0315] The pressure-sensitive adhesive composition (i) may contain only one type of energy ray-polymerizable compound, or may contain two or more types of energy ray-polymerizable compounds.

[0316] The content of the energy ray-polymerizable compound in the pressure-sensitive adhesive composition (i) is preferably 1 to 125 parts by mass, and more preferably 10 to 125 parts by mass, per 100 parts by mass of the acrylic resin.

[0317] (Photopolymerization initiator) The pressure-sensitive adhesive composition (i) may contain a photopolymerization initiator in addition to the acrylic resin and the energy ray-polymerizable compound.

[0318] The photopolymerization initiator may be a known one, and specifically, for example, an α-ketol compound such as 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, 1-hydroxycyclohexylphenyl ketone, or 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one; Acetophenone-based compounds such as acetophenone, dimethylaminoacetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1; Benzoin ether compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, and anisoin methyl ether; Ketal compounds such as benzil dimethyl ketal and acetophenone dimethyl ketal; Aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime, ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime); Benzophenone compounds such as benzophenone, p-phenylbenzophenone, benzoylbenzoic acid, dichlorobenzophenone, 4,4'-diethylaminobenzophenone, and 3,3'-dimethyl-4-methoxybenzophenone; Anthraquinone compounds such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, and 2-aminoanthraquinone; Thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 2,4-diisopropylthioxanthone; Examples of suitable acylphosphine oxides include p-dimethylaminobenzoic acid esters, camphorquinone, halogenated ketones, acylphosphine oxides such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, acylphosphonates, and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone].

[0319] The pressure-sensitive adhesive composition (i) may contain only one type of photopolymerization initiator, or may contain two or more types of photopolymerization initiators.

[0320] When a photopolymerization initiator is used, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition (i) is preferably 0.1 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 100 parts by mass of the content of the energy ray-polymerizable compound. When the content of the photopolymerization initiator is equal to or greater than the lower limit, the effect of using the photopolymerization initiator can be sufficiently obtained. Furthermore, when the content of the photopolymerization initiator is equal to or less than the upper limit, the generation of by-products from the excess photopolymerization initiator is suppressed, and the curing of the pressure-sensitive adhesive layer proceeds more smoothly.

[0321] (Crosslinking agent) The pressure-sensitive adhesive composition (i) may further contain a crosslinking agent in addition to the acrylic resin and the energy ray-polymerizable compound.

[0322] Examples of the crosslinking agent include organic polyvalent isocyanate compounds and organic polyvalent imine compounds.

[0323] Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and trimers, isocyanurates, and adducts of these compounds, as well as terminal isocyanate urethane prepolymers obtained by reacting the aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, or alicyclic polyisocyanate compounds with polyol compounds. The adducts refer to the reaction products of the aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, or alicyclic polyisocyanate compounds with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, or castor oil.

[0324] More specific examples of the organic polyisocyanate compound include 2,4-tolylene diisocyanate; 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate; 1,4-xylylene diisocyanate; diphenylmethane-4,4'-diisocyanate; diphenylmethane-2,4'-diisocyanate; 3-methyldiphenylmethane diisocyanate; hexamethylene diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4,4'-diisocyanate; dicyclohexylmethane-2,4'-diisocyanate; a compound in which either or both of tolylene diisocyanate and hexamethylene diisocyanate are added to all or some of the hydroxyl groups of a polyol such as trimethylolpropane; lysine diisocyanate, and the like.

[0325] Examples of the organic polyvalent imine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine, and the like.

[0326] When an isocyanate compound is used as a crosslinking agent, it is preferable to use a hydroxyl group-containing polymer as the acrylic resin. When the crosslinking agent has an isocyanate group and the acrylic resin has a hydroxyl group, a crosslinked structure can be easily introduced into the pressure-sensitive adhesive layer by the reaction between the isocyanate group and the hydroxyl group. The pressure-sensitive adhesive composition (i) may contain only one type of crosslinking agent or two or more types of crosslinking agents.

[0327] When a crosslinking agent is used, the content of the crosslinking agent in the pressure-sensitive adhesive composition (i) is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 16 parts by mass, per 100 parts by mass of the acrylic resin.

[0328] (solvent) The pressure-sensitive adhesive composition (i) preferably further contains a solvent in addition to the acrylic resin and the energy ray-polymerizable compound.

[0329] The solvent is not particularly limited, but preferred examples include hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (also called 2-methylpropan-1-ol), and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; amides (i.e., compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone, etc. The solvent contained in the pressure-sensitive adhesive composition (i) may be one type only, or two or more types.

[0330] When the pressure-sensitive adhesive composition (i) contains a solvent, the content of the solvent is preferably from 40 to 90 mass %, and more preferably from 50 to 80 mass %, based on the total mass of the pressure-sensitive adhesive composition.

[0331] (Other Ingredients) The pressure-sensitive adhesive composition (i) may further contain, in addition to the acrylic resin and the energy ray-polymerizable compound, other components not corresponding to the photopolymerization initiator, the crosslinking agent, and the solvent, within a range that does not impair the effects of the present invention.

[0332] The other components may be known ones and may be arbitrarily selected depending on the purpose, and are not particularly limited, but preferred ones include various additives such as colorants (dyes, pigments), deterioration inhibitors, antistatic agents, flame retardants, silicone compounds, chain transfer agents, etc. The other components contained in the pressure-sensitive adhesive composition (i) may be one type only or two or more types.

[0333] [Adhesive composition (ii)] The pressure-sensitive adhesive composition (ii) contains, as essential components, an acrylic resin having a hydroxyl group and a polymerizable group on a side chain (for example, an acrylic resin having a hydroxyl group and a polymerizable group on a side chain via a urethane bond), and an isocyanate-based crosslinking agent.

[0334] When adhesive composition (ii) is used, the acrylic resin has a polymerizable group on its side chain, and therefore the adhesive layer has reduced adhesion after polymerization reaction (curing) and thus has improved peelability from the adherend, compared to the case of adhesive composition (i), in which an energy ray-polymerizable compound is used and polymerization reaction is carried out by irradiation with energy rays, thereby improving the pick-up ability of the semiconductor chip with the protective film.

[0335] In this specification, the term "acrylic resin" in the pressure-sensitive adhesive composition (ii) means "acrylic resin having a polymerizable group in the side chain", unless otherwise specified.

[0336] (Acrylic resin) Examples of the acrylic resin having the above-mentioned polymerizable group in a side chain include those obtained by copolymerizing, as monomers, a hydroxyl group-free (meth)acrylic acid ester that does not have a hydroxyl group and a hydroxyl group-containing compound such as a hydroxyl group-containing (meth)acrylic acid ester that has a hydroxyl group, and reacting the hydroxyl group of the obtained hydroxyl group-containing copolymer with an isocyanate group of a compound having an isocyanate group and a polymerizable group to form a urethane bond.

[0337] Examples of the non-hydroxyl group-containing (meth)acrylic ester include (meth)acrylic esters other than hydroxyl group-containing (meth)acrylic esters among the (meth)acrylic esters in the pressure-sensitive adhesive composition (i).

[0338] Moreover, examples of the hydroxyl group-containing compound include the same compounds as the hydroxyl group-containing (meth)acrylic acid ester in the pressure-sensitive adhesive composition (i).

[0339] The acrylic resin may contain only one type of each of the non-hydroxyl group-containing (meth)acrylic ester and the hydroxyl group-containing compound, or two or more types thereof.

[0340] Examples of the compound having an isocyanate group and a polymerizable group include isocyanate group-containing (meth)acrylic acid esters such as 2-methacryloyloxyethyl isocyanate.

[0341] The compound having an isocyanate group and a polymerizable group constituting the acrylic resin may be of one type or two or more types.

[0342] The pressure-sensitive adhesive composition (ii) may contain only one type of acrylic resin, or two or more types of acrylic resins.

[0343] The content of the acrylic resin in the pressure-sensitive adhesive composition (ii) is preferably 80 to 99 mass %, more preferably 90 to 97 mass %, based on the total mass of all components contained in the pressure-sensitive adhesive composition (ii) other than the solvent.

[0344] (Isocyanate-based crosslinking agent) The isocyanate-based crosslinking agent may be, for example, the same as the organic polyvalent isocyanate compound that is the crosslinking agent in the pressure-sensitive adhesive composition (i). The pressure-sensitive adhesive composition (ii) may contain only one type of isocyanate-based crosslinking agent, or two or more types of isocyanate-based crosslinking agents.

[0345] The number of moles of isocyanate groups in the isocyanate crosslinking agent in the adhesive composition (ii) is preferably 0.2 to 3 times the number of moles of hydroxyl groups in the acrylic resin in the adhesive composition (ii). When the number of moles of isocyanate groups is equal to or greater than the lower limit, the adhesive layer after curing has a reduced adhesiveness, improving the peelability from the adherend, and improving the pick-up property of the semiconductor chip with the protective film. When the number of moles of isocyanate groups is equal to or less than the upper limit, the generation of by-products due to the reaction between isocyanate crosslinking agents can be further suppressed.

[0346] The content of the isocyanate crosslinking agent in the pressure-sensitive adhesive composition (ii) may be appropriately adjusted so that the number of moles of isocyanate groups falls within the range described above. While satisfying such conditions, the content is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and particularly preferably 0.3 to 12 parts by mass, relative to 100 parts by mass of the acrylic resin.

[0347] (Photopolymerization initiator) The pressure-sensitive adhesive composition (ii) may contain a photopolymerization initiator in addition to the acrylic resin and the isocyanate crosslinking agent.

[0348] The photopolymerization initiator may be, for example, the same as that in the case of the pressure-sensitive adhesive composition (i). The photopolymerization initiator contained in the pressure-sensitive adhesive composition (ii) may be one type or two or more types.

[0349] When a photopolymerization initiator is used, the content of the photopolymerization initiator in the pressure-sensitive adhesive composition (ii) is preferably 0.05 to 20 parts by mass per 100 parts by mass of the acrylic resin.

[0350] When the content of the photopolymerization initiator is equal to or more than the lower limit, the effect of using the photopolymerization initiator can be sufficiently obtained. Also, when the content of the photopolymerization initiator is equal to or less than the upper limit, the generation of by-products from the excess photopolymerization initiator is suppressed, and the curing of the pressure-sensitive adhesive layer proceeds more smoothly.

[0351] (solvent) The pressure-sensitive adhesive composition (ii) preferably further contains a solvent in addition to the acrylic resin and the isocyanate-based crosslinking agent.

[0352] The solvent may be, for example, the same as that in the case of the pressure-sensitive adhesive composition (i). The pressure-sensitive adhesive composition (ii) may contain only one type of solvent, or two or more types of solvents.

[0353] When the pressure-sensitive adhesive composition (ii) contains a solvent, the content of the solvent is preferably 40 to 90 mass %, more preferably 50 to 80 mass %, based on the total mass of the pressure-sensitive adhesive composition (ii).

[0354] (Other Ingredients) The pressure-sensitive adhesive composition (ii) may contain, in addition to the acrylic resin and isocyanate crosslinking agent, other components not corresponding to the photopolymerization initiator and the solvent, within the range not impairing the effects of the present invention.

[0355] Examples of the other components include the same components as those in the pressure-sensitive adhesive composition (i). The pressure-sensitive adhesive composition (ii) may contain only one type of other component, or two or more types of other components.

[0356] Although the pressure-sensitive adhesive composition containing a component that polymerizes upon irradiation with energy rays has been described above, a pressure-sensitive adhesive composition that does not contain a component that polymerizes upon irradiation with energy rays may be used to form the pressure-sensitive adhesive layer. In other words, the pressure-sensitive adhesive layer may be a non-energy ray-curable one that does not have energy ray curability.

[0357] A preferred example of such a non-energy ray-curable pressure-sensitive adhesive composition is one containing an acrylic resin and a crosslinking agent (hereinafter, sometimes abbreviated as "pressure-sensitive adhesive composition (iii)"), and may contain optional components such as a solvent and other components not corresponding to a solvent.

[0358] [Adhesive composition (iii)] The acrylic resin, crosslinking agent, solvent and other components contained in the pressure-sensitive adhesive composition (iii) are all the same as those in the pressure-sensitive adhesive composition (i).

[0359] The content of the acrylic resin in the pressure-sensitive adhesive composition (iii) is preferably 40 to 99 mass %, more preferably 50 to 97 mass %, based on the total mass of all components contained in the pressure-sensitive adhesive composition (iii) other than the solvent.

[0360] The content of the crosslinking agent in the pressure-sensitive adhesive composition (iii) is preferably from 2 to 30 parts by mass, and more preferably from 4 to 25 parts by mass, per 100 parts by mass of the acrylic resin.

[0361] Except for the above-mentioned points, the pressure-sensitive adhesive composition (iii) is the same as the pressure-sensitive adhesive composition (i).

[0362] <<Method of manufacturing pressure-sensitive adhesive composition>> The above-mentioned pressure-sensitive adhesive compositions, such as pressure-sensitive adhesive compositions (i) to (iii), can be obtained by blending the above-mentioned pressure-sensitive adhesive and, if necessary, components other than the above-mentioned pressure-sensitive adhesive, for constituting the pressure-sensitive adhesive composition.

[0363] The order of addition of the components when blending is not particularly limited, and two or more components may be added simultaneously.

[0364] The method for mixing the components during blending is not particularly limited, and may be appropriately selected from known methods such as a method of mixing by rotating a stirrer or stirring blades, a method of mixing using a mixer, a method of mixing by adding ultrasound, etc.

[0365] The temperature and time during addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and may be adjusted appropriately. A temperature of 15 to 30°C is preferred.

[0366] Release film The release film may be, for example, a known release film having a release-treated surface used in this field. The release treatment on the release-treated surface may be a treatment with various release agents such as alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, or wax-based. In terms of heat resistance, the release agent is preferably an alkyd-based, silicone-based, or fluorine-based release agent.

[0367] The thickness of the release film is not particularly limited, but is preferably 20 to 85 μm, and more preferably 25 to 75 μm. When the thickness of the release film is equal to or greater than the lower limit, the release film can be more easily peeled off at the intended stage, and after the protective film-forming sheet is wound into a roll, the release film is less likely to leave a trace of winding. On the other hand, when the thickness of the release film is equal to or less than the upper limit, the effect of suppressing peeling of the release film at an unintended stage is enhanced.

[0368] <Method of manufacturing the sheet for forming a protective film> The sheet for forming a protective film in this embodiment can be manufactured by a manufacturing method including a step of forming a laminated structure between the support sheet and the film for forming a protective film (hereinafter sometimes referred to as the "lamination step (P1)"), and a step of forming a laminated structure between the film for forming a protective film and the release film (hereinafter sometimes referred to as the "lamination step (P2)").

[0369] When the support sheet is made of a plurality of layers, the support sheet may be manufactured by laminating the plurality of layers.

[0370] When manufacturing a support sheet in which another layer (e.g., a pressure-sensitive adhesive layer, an intermediate layer, a coating layer, etc.) is laminated on a substrate, for example, a composition containing a component for constituting the other layer (e.g., a pressure-sensitive adhesive composition, a composition for forming an intermediate layer, a coating composition, etc.) may be applied to the surface of the substrate and dried as necessary to laminate the other layer on the substrate. In addition, when manufacturing a support sheet in which another layer is laminated on a substrate, for example, a composition containing a component for constituting the other layer may be applied to the release-treated surface of a release material and dried as necessary to form the other layer on the release material in advance, and then the surface (exposed surface) of the other layer formed may be attached to the surface of the substrate to laminate the other layer on the substrate. In this case, the release material may be removed as necessary, for example, before performing some operation on the other layer, such as when laminating a film for forming a protective film on the other layer.

[0371] As the release material, any material known in this field may be used, and for example, the same material as the above-mentioned release film constituting the sheet for forming a protective film according to this embodiment may be used.

[0372] For example, it is possible to form another layer by directly applying the desired composition to a substrate on one or both surfaces of which the other layer is already laminated. However, in such a case, it is preferable to adopt a method of laminating the other layer, which is formed in advance on a release material, to the substrate or the other layer already laminated on the substrate, as described above.

[0373] In the above-mentioned lamination process (P1), the laminated structure of the support sheet and the film for forming a protective film can be formed, for example, by applying a composition for the film for forming a protective film to the surface of the support sheet and drying it as necessary to form the film for forming a protective film (hereinafter, this process may be particularly referred to as "lamination process (P1)-11").

[0374] In the lamination step (P1), the laminated structure of the support sheet and the film for forming a protective film can be formed, for example, by the same method as in the case of producing the support sheet consisting of multiple layers described above. That is, the composition for the film for forming a protective film is applied to the release-treated surface of the release material, and dried as necessary to form a film for forming a protective film on the release material in advance, and then the surface of the formed film for forming a protective film on the side on which the release material is not provided is bonded to the surface of the support sheet, thereby forming a laminated structure of the support sheet and the film for forming a protective film (hereinafter, this step may be particularly referred to as "lamination step (P1)-12").

[0375] As the release material in this method, any material known in this field may be used, and for example, the same material as the above-mentioned release film constituting the sheet for forming a protective film according to this embodiment is preferable.

[0376] For example, even when the support sheet is a substrate having the other layers laminated on one or both surfaces, it is possible to directly apply the composition for the protective film-forming film onto such a support sheet to form a film for forming a protective film. However, even in such a case, it is preferable to adopt a method in which the film for forming a protective film, which has been formed in advance on a release material, is bonded to the support sheet in the lamination step (P1) as described above.

[0377] When the above-mentioned lamination step (P1)-11 is adopted as the lamination step (P1), in the lamination step (P2), the release film is bonded to the surface of the protective film-forming film on the side on which the support sheet is not provided.

[0378] On the other hand, when the above-mentioned lamination process (P1)-12 is adopted as the lamination process (P1), in the lamination process (P2), the release material provided on the surface of the film for forming a protective film opposite the side on which the support sheet is provided is removed to expose one surface of the film for forming a protective film, and then the release film is bonded to the exposed surface of the film for forming a protective film.

[0379] Furthermore, when the above-mentioned lamination step (P1)-12 is adopted as the lamination step (P1), by adopting the release film (the release film constituting the sheet for forming a protective film in this embodiment) as the release material for forming the film for forming a protective film in advance, this lamination step (P1)-12 also serves as the lamination step (P2). This manufacturing method is preferable in that the manufacturing process can be simplified. Hereinafter, the step of forming a laminated structure of the support sheet and the film for forming a protective film in this manufacturing method may be particularly referred to as the "lamination step (P1')".

[0380] For example, when manufacturing a protective film-forming sheet in which the protective film-forming film has a smaller surface area than the adhesive layer when viewed in a plan view from above the release film side, as shown in Figure 7, in the above-mentioned manufacturing method, the protective film-forming film, which has been cut out in advance to a predetermined size and shape, can be placed on the adhesive layer.

[0381] In producing the sheet for forming a protective film according to this embodiment, the film for forming a protective film can be formed by applying the composition for forming a protective film to the surface on which the film for forming a protective film is to be formed, as described above.

[0382] In the production of the sheet for forming a protective film according to the present embodiment, for example, the pressure-sensitive adhesive layer can be formed by applying the pressure-sensitive adhesive composition to the surface on which the pressure-sensitive adhesive layer is to be formed, and preferably drying the composition. The pressure-sensitive adhesive composition can be applied in the same manner as in the case of the composition for forming a protective film.

[0383] The applied pressure-sensitive adhesive composition may be crosslinked by heating, and this crosslinking by heating may be performed together with drying. The heating conditions may be, for example, but are not limited to, 100 to 130° C. for 1 to 5 minutes.

[0384] Hereinafter, as an example of a method for producing a sheet for forming a protective film according to this embodiment having the configuration shown in Fig. 2, a production method having the lamination step (P1') will be described with reference to Fig. 9. Note that the production method described here is only one example, and when other production methods for a sheet for forming a protective film having the configuration shown in Fig. 2 or other production methods for a sheet for forming a protective film have steps that are the same as or similar to the steps described below, such steps can also be performed in the same manner as the steps described below.

[0385] In this method, a thermosetting composition for a film for forming a protective film or an energy ray curable composition for a film for forming a protective film is applied to the release treatment surface 15b of the release film 15 to form a film for forming a protective film 13 as shown in Fig. 9(a). Note that, in this example, the film for forming a protective film 13 is disposed below the release film 15 to facilitate comparison with the sheet for forming a protective film 1B, but this does not mean that the orientation of the release treatment surface 15b of the release film 15 during application of the protective film-forming composition is limited to the downward orientation as shown in Fig. 9(a), and may be the opposite, upward orientation, and is preferably upward orientation.

[0386] In addition, a separate release material may be attached (not shown) to the surface (exposed surface) of the formed protective film-forming film 13 opposite to the side in contact with the release film 15. The release material here may be the same as the release material to be coated with the pressure-sensitive adhesive composition described later.

[0387] In this method, the adhesive composition is then applied to the release treated surface 90b of the release material 90 to form the adhesive layer 12 as shown in Fig. 9(b). Again, to facilitate comparison with the protective film-forming sheet 1B, an example is shown in which the adhesive layer 12 is disposed below the release material 90, but this does not mean that the orientation of the release treated surface 90b of the release material 90 during application of the adhesive composition is limited to the downward orientation as shown in Fig. 9(b), and it may be the opposite, upward orientation, and is preferably upward orientation.

[0388] 9(c), the substrate 11 is then bonded to the surface (exposed surface) of the adhesive layer 12 opposite to the side in contact with the release material 90. At this time, the surface of the substrate 11 to which the adhesive layer 12 is bonded is selected so that the surface roughness of the surface 11b of the substrate 11 on the side to which the adhesive layer 12 is not bonded is 0.5 μm or less. In this manner, the support sheet 10 is obtained.

[0389] In this method, next, as shown in Fig. 9(d), the release material 90 provided on the adhesive layer 12 in the support sheet 10 is removed to expose the exposed surface of the adhesive layer 12, and the exposed surface of the film 13 for forming a protective film is bonded to the exposed surface of the film 13 for forming a protective film, to obtain a sheet 1B for forming a protective film, as shown in Fig. 9(e). When the above-mentioned release material is separately bonded to the surface (exposed surface) of the film 13 for forming a protective film opposite to the side in contact with the release film 15, this release material may be removed before bonding the exposed surface of the film 13 for forming a protective film to the exposed surface of the adhesive layer 12.

[0390] Next, a method for producing the sheet for forming a protective film according to this embodiment having the configuration shown in FIG. 1 will be described (not shown).

[0391] In this method, the above-mentioned method for producing the sheet for protective film formation 1B can be used.

[0392] First, a laminated sheet having a release film 15 laminated on one side of an adhesive tape for forming a jig adhesive layer 16 is used, and a cut is formed in a desired shape at a desired location on the adhesive tape. Here, the desired shape is, for example, a shape that is circular when viewed from above the surface of the laminated sheet.

[0393] Next, the adhesive tape having the desired shape (for example, a circle in the plan view) is removed from the laminate sheet, and the processed laminate sheet is left with the release material exposed in the area where the adhesive tape has been removed. That is, when the adhesive tape having a circle shape in the plan view is removed, the processed laminate sheet has the adhesive tape cut out in the desired location.

[0394] Next, the release film 15 is removed from the protective film-forming sheet 1B obtained above, and the exposed surface of the protective film-forming film 13 and the adhesive tape of this processed laminated sheet are bonded together to obtain the protective film-forming sheet 1A shown in Fig. 1. In this method, when a sheet wound into a roll is not used as the protective film-forming sheet 1B, a protective film-forming sheet having the same configuration as the protective film-forming sheet 1B may be used as the object to be bonded to the processed laminated sheet, except that it has a known release material instead of the release film 15.

[0395] However, the above-mentioned manufacturing method is only one example, and the manufacturing method of the sheet for protective film formation 1A is not limited to this.

[0396] <How to use the protective film forming sheet> The method of using the sheet for forming a protective film according to this embodiment is, for example, as follows.

[0397] First, a method of using the sheet for forming a protective film when the film for forming a protective film is thermosetting will be described.

[0398] When the protective film forming film is thermosetting, first, the back surface of the semiconductor wafer is attached to the protective film forming film of the protective film forming sheet, and the protective film forming sheet is fixed to a dicing device.

[0399] Next, the protective film-forming film is cured by heating to form a protective film. When a backgrind tape is attached to the surface (electrode formation surface) of the semiconductor wafer, the backgrind tape is usually removed from the semiconductor wafer before the protective film is formed.

[0400] Next, the semiconductor wafer is diced together with the protective film to obtain semiconductor chips. Between the formation of the protective film and the dicing, the protective film can be irradiated with laser light from the support sheet side of the protective film formation sheet to perform printing (laser printing) on ​​the surface of the protective film.

[0401] Next, the semiconductor chip is peeled off from the support sheet together with the protective film after cutting that is attached to the back surface thereof, and picked up to obtain a semiconductor chip with a protective film. For example, when the support sheet is a sheet in which a base material and an adhesive layer are laminated, and the adhesive layer is an energy ray curable layer, the adhesive layer is cured by irradiation with energy rays, and the semiconductor chip is picked up from the cured adhesive layer together with the protective film that is attached to the back surface thereof, thereby more easily obtaining a semiconductor chip with a protective film.

[0402] The resulting semiconductor chips with protective film are picked up one by one and transported to the next process.

[0403] Thereafter, the semiconductor chip with the protective film is mounted in a reflow process. For example, the obtained semiconductor chip with the protective film can be mounted on the circuit surface of the substrate by flip-chip bonding. The whole is then sealed with resin to form a semiconductor package. The semiconductor package can then be used to manufacture the desired semiconductor device.

[0404] Although the above description has been given of the case where the protective film-forming film is cured to form a protective film and then diced, the protective film may be formed by curing the protective film-forming film after the dicing. Laser marking may also be performed when the protective film-forming film is in an uncured state. Laser marking is performed on the protective film-forming film, and then the protective film-forming film is cured, thereby obtaining a semiconductor wafer having a laser-printed protective film.

[0405] Next, a method of using the sheet for forming a protective film when the film for forming a protective film is energy ray curable will be described.

[0406] When the film for forming a protective film is energy ray curable, first, in the same manner as in the case where the film for forming a protective film described above is heat curable, the back surface of the semiconductor wafer is attached to the film for forming a protective film of the sheet for forming a protective film, and the sheet for forming a protective film is fixed to a dicing device.

[0407] Next, the protective film-forming film is cured by irradiating it with energy rays to form a protective film. When a backgrind tape is attached to the surface (electrode formation surface) of the semiconductor wafer, the backgrind tape is usually removed from the semiconductor wafer before the protective film is formed.

[0408] Next, the semiconductor wafer together with the protective film is diced to obtain semiconductor chips. Between the formation of the protective film and the dicing, the protective film can be irradiated with laser light from the support sheet side of the protective film-forming sheet to perform printing on the surface of the protective film.

[0409] Next, the semiconductor chips are peeled off from the support sheet together with the protective film attached to the rear surface thereof after cutting and picked up, thereby obtaining semiconductor chips with protective films.

[0410] This method is particularly suitable when, for example, a support sheet in which a substrate and a pressure-sensitive adhesive layer are laminated as the protective film-forming sheet is used, and the pressure-sensitive adhesive layer is not energy ray curable.

[0411] For example, when a sheet for forming a protective film is used in which the support sheet is formed by laminating a substrate and a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is energy ray-curable, the method described below is preferred.

[0412] That is, first, in the same manner as in the above case, the back surface of the semiconductor wafer is attached to the film for forming a protective film of the sheet for forming a protective film, and the sheet for forming a protective film is fixed to a dicing device.

[0413] Next, if necessary, the film for forming a protective film is irradiated with laser light from the support sheet side of the sheet for forming a protective film to print on the surface of the film for forming a protective film, and then the semiconductor wafer is diced to obtain semiconductor chips.

[0414] Next, the protective film-forming film is cured by irradiation with energy rays to form a protective film, and the adhesive layer is cured, and the semiconductor chip is picked up together with the protective film attached to its back surface from the cured adhesive layer to obtain a semiconductor chip with a protective film. The printing applied to the surface of the protective film-forming film is maintained in the same state on the protective film.

[0415] The subsequent steps are the same as those in the case where the above-mentioned protective film-forming film is thermosetting.

[0416] In addition, the method described here can be modified in the same way as in the case where the above-mentioned film for forming a protective film is thermosetting. That is, although the case where the film for forming a protective film is cured to form a protective film and then diced has been described so far, the film for forming a protective film may be diced without curing, and the film for forming a protective film may be cured after this dicing to form a protective film. EXAMPLES

[0417] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited to the following examples.

[0418] The raw materials used in the production of the composition for forming a protective film are shown below.

[0419] [Polymer component (A)] (A)-1: Acrylic polymer: an acrylic polymer obtained by copolymerizing 15 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, 60 parts by mass of methyl acrylate, and 15 parts by mass of 2-hydroxyethyl acrylate (weight average molecular weight: 600,000, glass transition temperature: 1°C)

[0420] [Thermosetting component (B)] Epoxy resin (B1) (B1)-1: Bisphenol A type liquid epoxy resin (manufactured by Nippon Shokubai Co., Ltd., BPA328, epoxy equivalent 230) (B1)-2: Bisphenol A type epoxy resin ("jER1055" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 800-900) (B1)-3: Bisphenol F type liquid epoxy resin ("jERYL983U" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 165 to 175)

[0421] ·Heat hardener (B2) (B2)-1: Dicyandiamide (thermally activated latent epoxy resin hardener, ADEKA Corporation's "ADEKA Hardener EH-3636AS")

[0422] [Cure accelerator (C)] (C)-1: 2-phenyl-4,5-dihydroxymethylimidazole ("Curesol 2PHZ" manufactured by Shikoku Chemical Industries, Ltd.)

[0423] [Filling material (D)] (D)-1: Silica filler (Admatechs SC105G-MMQ: spherical silica, average particle size 0.3μm)

[0424] [Coupling agent (E)] (E)-1: 3-glycidoxypropyltrimethoxysilane (3-glycidyloxypropyltrimethoxysilane) (Shin-Etsu Chemical Co., Ltd., KBM403)

[0425] [Colorant (I)] (I)-1: Carbon black ("MA600B" manufactured by Mitsubishi Chemical Corporation, average particle size 28 nm)

[0426] The support sheet and release film used are as follows: The support sheet is an adhesive tape commercially available as a dicing sheet. Substrate: Lintec Adwill G-535H (thickness 90 μm) Release film: SP-PET381130 (thickness 38 μm) manufactured by Lintec Corporation

[0427] [Example 1] <Production of protective film-forming sheet> (Production of a film composition for forming a thermosetting protective film) As shown in Table 1, polymer component (A)-1 (20 parts by mass), epoxy resin (B1)-1 (15 parts by mass), epoxy resin (B1)-2 (1.8 parts by mass), heat curing agent (B2)-1 (0.45 parts by mass), curing accelerator (C)-1 (0.45 parts by mass), filler (D)-1 (60 parts by mass), coupling agent (E)-1 (0.4 parts by mass), and colorant (I)-1 (1.9 parts by mass) were mixed, and methyl ethyl ketone was further mixed and stirred at 23 ° C. for 60 minutes to obtain a composition for forming a protective film (1-1) having a solid content of 52% by mass. Note that the blending amounts of components other than methyl ethyl ketone shown here and in Table 1 are all solid contents.

[0428] (Formation of protective film) The composition for protective film formation (1-1) obtained above was applied onto the release-treated surface of the release film using a knife coater, and dried for 2 minutes at 110° C. to form a film for protective film formation having a thickness of 25 μm. Furthermore, the release-treated surface of the release film was attached to the exposed surface of the film for protective film formation on the side opposite to the side on which the release film was provided.

[0429] (Manufacture of protective film forming sheets) The release film was removed from one surface of the film for forming a protective film obtained above, and the release film provided on the adhesive layer of the support sheet was also removed, and the exposed surface of the film for forming a protective film was laminated to the exposed surface of the adhesive layer to obtain a sheet for forming a protective film having the substrate, the adhesive layer, the film for forming a protective film, and the release film laminated in this order.

[0430] (Manufacturing of silicon chips with protective film) The obtained sheet for forming a protective film was attached to the #2000 polished surface of a 6-inch silicon wafer (thickness 100 μm) via the film for forming a protective film, and the sheet was then fixed to a ring frame and left to stand for 30 minutes. Next, the silicon wafer having the film for forming a protective film was heat-treated at 130° C. for 2 hours to harden the film for forming a protective film, thereby forming a protective film.

[0431] Next, the film for forming a protective film was laser-printed under the following conditions using a green laser marker (CSM300M manufactured by EO Tech). Wavelength: 532nm Output: 0.38W Frequency: 20kHz Scan speed: 100mm / s Printing characters: ABCD Character size: 300μm (height) x 200μm (width) Character line width: 35μm

[0432] Next, the silicon wafer was diced together with the protective film using a dicing blade to obtain individual silicon chips with a length of 3 mm, a width of 3 mm, a protective layer thickness of 25 μm, and a Si layer thickness of 350 μm. Next, the silicon chips with the protective film were picked up using a die bonder (Canon Machinery's "BESTEM-D02"). A silicon chip with a printed protective film was obtained.

[0433] The silicon chip with the protective film was subjected to a heat treatment at 260°C for 10.8 minutes and then returned to room temperature. This operation was repeated three times. This operation imitates the reflow process carried out in the mounting process. The chip before the heat treatment is labeled "before reflow process" and the chip after the heat treatment is labeled "after reflow process."

[0434] (Color Measurement) Before and after the reflow process, the printed and non-printed areas were measured using the SE6000 manufactured by Nippon Denshoku Industries Co., Ltd., with a C / 2 light source reflected, in accordance with CIE1976L * a * b * Lightness L in color system * , chromaticity a * , chromaticity b * was measured. Color difference ΔE between printed and non-printed areas * ab The lightness difference ΔL* was also calculated. The results are shown in Table 1.

[0435] (Evaluation of visibility) The visibility of the print before and after the reflow process was evaluated according to the following criteria, and the results are shown in Table 1. Good: More than 4 out of 5 people could see the print Possible: 2-3 out of 5 people were able to see the print Poor: Fewer than 1 in 5 people could see the print

[0436] [Examples 2 and 3, Comparative Example 1] In the production of the thermosetting protective film-forming film composition, a sheet for forming a protective film was produced in the same manner as in Example 1, except that the components were changed as shown in Table 1, and a silicon chip with a protective film was obtained. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[0437] [Table 1]

[0438] From the above results, it was confirmed that with the protective film forming film of this embodiment, sufficient print visibility can be obtained even when the printed line width is narrow during the hardening or reflow process of the protective film forming film. [Explanation of symbols]

[0439] 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H... Sheet for forming protective film, 10... Support sheet, 10a: Surface of the support sheet; 10b: Back surface (exposed surface) of the support sheet; 11...Base material, 11a...A surface of a substrate; 11b... The back surface of the substrate; 12... Adhesive layer, 12a: A surface of the adhesive layer; 13,23...protective film forming layer, 13a, 23a: Surface of protective film forming layer; 14...coating layer, 14a... Surface of the coating layer; 14b: the back surface of the coating layer; 15...Release film, 15a Surface of release film

Claims

1. A protective film for forming a protective film, the surface of which is laser-printed, CIE1976L * a * b * In the coordinate system specified by the color system, the color of the printed part is expressed as lightness L * p , chromaticity a * p , chromaticity b * p and CIE1976L * a * b * In the coordinate system defined by the color system, the color of the non-printed part is expressed as lightness L * N , chromaticity a * N , chromaticity b * N The color of the printed portion and the color of the non-printed portion are measured after the protective film-forming film is heated to 180° C. and hardened after laser printing, and then heated three times at 260° C. for 10.8 minutes. The color difference ΔE between the printed and non-printed areas is defined by the following formula (A): * ab A film for forming a protective film, wherein the film has a molecular weight of 8 or more. ΔE * ab =〔(L * p -L * N ) 2 +(a * p -a * N ) 2 +(b * p -b * N ) 2 〕 1 / 2 …(A)

2. The difference in brightness ΔL between the printed and non-printed areas is defined by the following formula (B): * The film for forming a protective film according to claim 1, wherein the molecular weight is 8 or more. ΔL * =〔(L * p -L * N ) 2 〕 1 / 2 …(B)

3. The brightness L of the printed portion * p and the brightness L of the non-printed part * N But, L * p >L * N 3. The film for forming a protective film according to claim 1 or 2, which satisfies the above.

4. A film for forming a protective film described in any one of claims 1 to 3, containing 1.5 mass % or more of carbon black.

5. The film for forming a protective film according to any one of claims 1 to 4, wherein the printed portion includes a portion having a line width of 50 µm or less.

6. A film for forming a protective film according to any one of claims 1 to 5, A support sheet; A sheet for forming a protective film comprising:

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