TW202406712A - Release film and method of producing semiconductor package - Google Patents

Abstract

A release film incudes a release layer and a substrate, in which the release layer has a breaking elongation rate of 100% or more, and surface roughness Ra of 0.2 μm or more.

Description

Release film and method for manufacturing semiconductor packaging

The invention relates to a release film and a method for manufacturing a semiconductor package.

Semiconductor wafers are usually sealed with resin to shield and protect them from outside air, and are mounted on a substrate in the form of a molded product called a package. Molded products are produced by injecting a sealing material containing resin into a mold. A plurality of cavities are provided in the mold, and the plurality of cavities are connected via a flow path serving as a flow path for the sealing material. In addition, we have worked hard on the structure of the mold and the addition of a release agent to the sealing resin so that the molded product can be easily released from the mold.

On the other hand, in terms of requirements such as miniaturization and multi-pin packaging, Ball Grid Array (BGA) method, Quad Flat Non-leaded (QFN) method, wafer-level chip size Packaging methods such as the Wafer Level-Chip Size Package (WL-CSP) method are added. In the QFN method, it ensures the standoff and prevents burrs caused by the sealing material at the terminal part. In addition, in the BGA method and WL-CSP method, it improves the releasability of the package from the mold. In terms of the mold, a resin release film is arranged along the inside of the mold, and a sealing material is injected into the mold to perform molding (for example, see Patent Document 1). The method of molding using a release film is called "film-assisted molding method". [Prior art documents] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-158242

[Problem to be solved by the invention] When the release film is used, flow marks of the sealing material may remain on the package surface after molding, and the appearance may be degraded. In order to reduce flow marks, consider adding fillers to the release layer of the release film. In addition, in recent years, a technology has been studied in which a plurality of packages are mounted on a substrate and then sealed together. In this case, since packages of various shapes exist on the substrate, excellent stretchability is required for the release film.

When the release film is stretched, the release layer also follows the elongation of the base material and is stretched. However, sometimes the release layer cannot completely follow and breaks, and the molded product cannot be separated from the mold or is difficult to remove. In particular, in a release film in which a filler is added to the release layer in order to reduce flow marks, the elongation of the release layer decreases and the release layer tends to break easily.

In view of this situation, an object of the present disclosure is to provide a release film that suppresses breakage of the release layer and can reduce flow marks of the sealing material on the surface of the semiconductor package, and a method for manufacturing a semiconductor package using the release film. [Means to solve the problem]

Means for solving the above problems include the following embodiments. <1> A release film, including a release layer and a base material layer, The elongation at break of the release layer is 100% or more, and the surface roughness Ra of the release layer is 0.2 μm or more. <2> The release film according to <1>, wherein the release layer contains two or more polymers, The difference in solubility parameter (SP) values of at least two of the polymers is more than 0.3. <3> The release film according to <1> or <2>, wherein the release layer contains two or more polymers, At least one of the polymers is a nitrile group-containing (meth)acrylic acid polymer. <4> The release film according to any one of <1> to <3>, wherein the release layer contains two or more polymers, and the two or more polymers are polymers derived from ( (Meth)acrylic acid polymer is a structural unit of meth)acrylyl monomer. <5> The release film according to any one of <1> to <4>, satisfying at least one of the following (1) or (2). (1) The release layer has a plurality of regions with different component ratios, and when Raman spectroscopy is measured in the different regions, different peak intensities are shown in at least a part of the different regions. (2) The surface of the release layer has an uneven shape, and when Raman spectroscopy is measured in the convex portions and the concave portions, different peak intensities are shown in at least a part of the convex parts and at least a part of the concave parts. . <6> The release film according to <5>, wherein in at least a part of the different regions, or in at least a part of the convex part and the recessed part, a polymer component The ratios are different. <7> The release film according to <5> or <6>, wherein in at least a part of the different plurality of regions, or in at least a part of the convex part and the recessed part, The content of nitrile group-containing (meth)acrylic polymers varies. <8> The release film according to any one of <5> to <7>, wherein the peak showing the different peak intensity is a peak derived from a nitrile group. <9> The release film according to any one of <5> to <8>, wherein the surface of the release layer has an uneven shape, and the peaks derived from a nitrile group in at least a part of the convex portions are The intensity is greater than the peak intensity derived from the nitrile group in at least a part of the recessed portion. <10> The release film according to any one of <5> to <9>, wherein the surface of the release layer has an uneven shape, and the nitrile group-containing (methane) in at least a part of the convex portion is The mass-based content of the nitrile group-containing (meth)acrylic polymer is greater than the mass-based content of the nitrile group-containing (meth)acrylic polymer in at least a part of the recessed portion. <11> The release film according to any one of <1> to <10>, wherein the release layer contains two or more polymers, at least one of the polymers is a polymer comprising structural units derived from (meth)acrylonitrile monomer, In at least two types of the polymers, the difference in the proportions of structural units derived from (meth)acrylonitrile monomer is 1 mass % or more. <12> The release film according to any one of <1> to <11>, wherein the content rate of the most abundant polymer in the release layer is 95 relative to the total content of the polymer. mass% or less. <13> The release film according to any one of <1> to <12>, wherein the base material layer is a polyester film. <14> The release film according to any one of <1> to <13>, wherein the thickness of the release layer is 1 μm to 50 μm. <15> The release film according to any one of <1> to <14>, which is used for transfer molding or compression molding. <16> A method of manufacturing a semiconductor package in which a transfer molding step or a compression molding step is performed using the release film according to any one of <1> to <15>. [Effects of the invention]

The present disclosure provides a release film that suppresses breakage of the release layer and can reduce flow marks of the sealing material on the surface of the semiconductor package, and a manufacturing method of a semiconductor package using the release film.

Hereinafter, modes for implementing the present disclosure will be described in detail. However, this disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps, etc.) are not essential unless otherwise stated. The same applies to numerical values and their ranges, which do not limit the disclosure.

In this disclosure, the term "step" includes not only steps that are independent of other steps, but also includes steps that are not clearly distinguishable from other steps as long as the purpose of the step is achieved. The numerical range expressed using "～" in this disclosure includes the numerical values described before and after "～" as the minimum value and the maximum value respectively. In the numerical ranges described in stages in the present disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit in another numerical range described in stages. In addition, in the numerical range described in this disclosure, the upper limit value or the lower limit value of this numerical range may be replaced with the value shown in the Example. In this disclosure, a variety of corresponding substances may be included in each component. When a plurality of substances corresponding to each component are present in the composition, the content rate or content of each component means the total content rate or content of the plurality of substances present in the composition unless otherwise specified. In the present disclosure, the term "layer" includes not only the case where the layer is formed in the entire region when the region where the layer exists is observed, but also the case where the layer is formed in only a part of the region.

In this disclosure, the thickness of the release film or each layer constituting the release film can be measured by a known method. For example, it can be measured using a dial gauge or the like, or it can be measured based on a cross-sectional image of the release film. Alternatively, the material constituting the layer may be removed using a solvent or the like and calculated based on the mass before and after removal, the density of the material, the area of the layer, etc. When the thickness of the layer is not constant, the arithmetic mean of the values measured at five arbitrary points is used as the thickness of the layer. In this disclosure, "(meth)acrylic acid" means either or both acrylic acid and methacrylic acid, and "(meth)acrylate" means either acrylate or methacrylate. Or both, "(meth)acrylyl" means any one or both of acryl and methacrylyl. When the embodiment is described with reference to the drawings in the present disclosure, the structure of the embodiment is not limited to the structure shown in the drawings. In addition, the sizes of the members in each figure are conceptual, and the relative size relationship between the members is not limited to this.

＜Mold release film＞ The release film of the present disclosure includes a release layer and a base material layer. The release elongation of the release layer is 100% or more, and the surface roughness Ra of the release layer is 0.2 μm or more.

In conventional release films, fillers are added to the release layer to create unevenness on the surface of the release layer, thereby reducing flow marks of the sealing material on the surface of the semiconductor package. However, in such a conventional release film, the release layer is easily broken starting from the filler.

In contrast, in the release film of the present disclosure, the breakage elongation of the release layer is 100% or more, thereby suppressing breakage of the release layer. In addition, the release film of the present disclosure can reduce flow marks on the surface of the semiconductor package after molding because the surface roughness Ra of the release layer is 0.2 μm or more.

As an example of the release film of this disclosure, the cross-sectional structure of the release film is schematically shown in FIG. 1 . As shown in FIG. 1 , the release film 30 includes a base material layer 10 and a release layer 20 . The release film 30 may also have other layers. Examples of other layers include a second release layer, an anchor improving layer, an antistatic layer, a colored layer, and the like.

[Release layer] The release layer is not particularly limited as long as it has an elongation at break of 100% or more and a surface roughness Ra of 0.2 μm or more. As an example of a preferred aspect, for example, the release layer contains two or more polymers and satisfies at least one of the following (1) to (4).

(1) The release layer has a plurality of regions with different component ratios, and when Raman spectroscopy is measured in the different regions, different peak intensities are shown in at least a part of the different regions. (2) The surface of the release layer has an uneven shape, and when Raman spectroscopy is measured in the convex portions and the concave portions, different peak intensities are shown in at least a part of the convex parts and at least a part of the concave parts. . (3) The difference in SP values of at least two of the polymers is 0.3 or more. (4) At least one of the polymers is a nitrile group-containing (meth)acrylic acid polymer.

In this disclosure, "polymer" refers to a high molecular weight component that does not contain organic fillers. Here, the organic filler is insoluble or poorly soluble in an organic solvent (for example, toluene, methyl ethyl ketone, and ethyl acetate) that can be used for adjusting the composition for forming a release layer. Here, the term "insoluble or poorly soluble in an organic solvent" means that the resin particles are dispersed in an organic solvent such as toluene in a gel fraction test based on Japanese Industrial Standard (JIS) K6769 (2013) The gel fraction after maintaining at 50°C for 24 hours was 97% by mass or more.

In this disclosure, "different types of polymers" means that the types of constituent monomers are different, or the types of constituent monomers are the same, but the content of structural units derived from at least one monomer differs by 1% by mass. above.

In this disclosure, "different peak intensities are displayed when Raman spectroscopy is measured" means that the peaks appearing at a certain position in the Raman spectrum obtained by Raman spectroscopy have different intensities. The difference between whether there is a wave peak at a certain position is also included in the situation where the intensity of the wave peak is different.

The reason why the release layer having the above structure has an elongation at break of 100% or more and a surface roughness Ra of 0.2 μm or more is not yet clear, but it is speculated as follows. In addition, the release film of this disclosure is not limited to the following speculation at all.

As described in (1), there are multiple regions with different component ratios. When Raman spectroscopy is measured in the different multiple regions, different peak intensities are shown in at least part of the different multiple regions, thereby forming a single In the region, the polymers agglomerate with each other, become denser and locally bulge, thereby forming an uneven shape on the surface of the release layer. When Raman spectrum measurement is performed, there are regions showing different peak intensities. That is, it can be said that the regions showing these different peak intensities have different component ratios. Furthermore, as described in (2), the surface of the release layer may have an uneven shape, and when Raman spectroscopy is measured in the convex portions and the concave portions, at least a portion of the convex portions and at least a portion of the concave portions may be Different peak intensities are shown in one part. The term "at least a part of the convex part and at least a part of the concave part show different peak intensities when Raman spectroscopy is measured" means that at least part of the convex part and at least a part of the concave part show different peak intensities when Raman spectroscopy is measured. Different wave peak intensities are enough. When there are a plurality of convex parts, the peak intensities of the respective convex parts may be the same or different. When there are a plurality of recessed portions, the peak intensities of the respective recessed portions may be the same or different. Thereby, regarding the release film described in (1) or (2), unevenness can be generated on the surface of the release film even if a filler is not added to the release layer. Therefore, in the release film of this disclosure, it is possible to form convex portions in which a clear interface cannot be confirmed. The term "convex portions in which a clear interface cannot be confirmed" means that when observed with a laser microscope, a particle interface cannot be confirmed as when a filler is added.

As one specific method of forming a plurality of regions with different polymer component ratios, as described in (3), two or more polymers whose SP value difference is 0.3 or more are used. Polymers with a difference in SP value of 0.3 or more have low compatibility, so they separate from each other and at the same time, polymers of the same type aggregate with each other, and release films of (1) and (2) can be obtained. In particular, as described in (4), when at least one of the polymers is a nitrile group-containing (meth)acrylic polymer, the nitrile group-containing (meth)acrylic polymers aggregate with each other and easily form convex portions. tendency.

In a release film that satisfies at least one of (1) to (4), unevenness can be formed on the surface even without adding a filler. Therefore, it is not necessary to add a filler or the filler amount can be reduced. As a result, the extensibility is excellent. In addition, since the release film of the present disclosure has an uneven shape on the surface, flow marks of the sealing material on the surface of the semiconductor package are reduced. Furthermore, since the surface roughness Ra of the release film of this disclosure is 0.2 micrometer or more, it is also excellent in releasability. Furthermore, in a release film that satisfies at least one of (1) to (4), it is not necessary to add a filler, so the occurrence of problems such as filler falling off can be suppressed.

As shown in (3) above, the difference in SP value of at least two polymers contained in the release layer is preferably 0.3 or more, more preferably 0.5 or more, and still more preferably 0.8 or more. The upper limit of the difference in SP values is not particularly limited, but is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.0 or less. In this disclosure, when there are two types of polymers contained in the release layer, the difference in SP value refers to the difference in SP value between the polymers. When the release layer contains three or more types of polymers, the difference in SP value refers to the difference between the polymer with the highest SP value and the polymer with the lowest SP value among the polymers contained in the release layer. The difference in SP value.

The SP value is a solubility parameter derived from the local structural unit of the chemical structural formula, and is a value calculated by the Fedors method.

The type of polymer is not particularly limited, but it is preferably selected considering the adhesion, releasability, heat resistance, etc. of the release layer. Specific examples of the polymer include (meth)acrylic polymers having structural units derived from (meth)acrylyl monomers, silicones, urethane polymers, and the like. At least one type of polymer is preferably a (meth)acrylic acid polymer, and more preferably two or more (meth)acrylic acid polymers are used. The proportion of the (meth)acrylic acid polymer in the total polymer is preferably 20 mass% or more, more preferably 40 mass% or more, further preferably 60 mass% or more, and may be 80 mass% or more, 85 mass% or more. % or more, 90 mass % or more, 95 mass % or more. The upper limit is not particularly limited, and the ratio may be 100% by mass, 95% by mass or less, 90% by mass or less, or 85% by mass or less.

The (meth)acrylic acid polymer may be a homopolymer or a copolymer, and a homopolymer and a copolymer may be used together. At least one of the (meth)acrylic acid polymers is preferably a copolymer. The copolymer may contain structural units derived from monomer A which does not have a functional group, or may contain structural units derived from monomer B which has a functional group.

Monomer A is preferably a monomer with a relatively low glass transition temperature (Tg) (for example, -20° C. or lower). Furthermore, a monomer with a relatively low Tg means a monomer with a relatively low glass transition temperature when a homopolymer is synthesized using the monomer. Examples of the monomer A include butyl (meth)acrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and the like. The copolymer may contain one structural unit derived from monomer A alone or in combination of two or more.

When the copolymer contains structural units derived from monomer A, the total content of the structural units derived from monomer A in the copolymer is preferably more than 50 mass %, more preferably 55 mass % or more, and still more preferably It is more than 60 mass%. In addition, the total content rate is preferably 99 mass% or less, more preferably 98 mass% or less, still more preferably 97 mass% or less.

At least one polymer is preferably a copolymer containing structural units derived from monomer B having a functional group. Examples of the functional group include a carboxylic acid group, a hydroxyl group, a amide group, a nitrile group, and the like. The functional group may be a cross-linking functional group or a non-cross-linking functional group. Examples of crosslinkable functional groups include carboxylic acid groups, hydroxyl groups, amide groups, and the like, and examples of non-crosslinkable functional groups include nitrile groups and the like. The copolymer may contain one structural unit derived from monomer B alone or in combination of two or more. More preferably, at least one polymer is a nitrile group-containing (meth)acrylic acid polymer.

At least part of the crosslinked polymer having a crosslinkable functional group may be crosslinked and included in the release film. In this disclosure, when two or more polymers are cross-linked, the release film is also included in the form containing two or more polymers.

When a polymer is cross-linked, the polymer before cross-linking can be analyzed or estimated by decomposing the bond passing through the cross-linking point. For example, when a polymer has a hydroxyl group and an isocyanate compound is used as a cross-linking agent, it is estimated that a urethane bond is formed and cross-linked, and the urethane bond can be selectively decomposed by pyridine.

The cross-linked polymer is preferably a cross-linked (meth)acrylic acid polymer, and more preferably a cross-linked (meth)acrylic acid copolymer.

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

In at least one polymer, the total content of structural units derived from monomer B1 is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and still more preferably 1.0 mass% or more. In addition, the total content rate is preferably 30 mass% or less, more preferably 25 mass% or less, and still more preferably 20 mass% or less.

In at least one kind of polymer, the total content of structural units derived from monomer B2 is preferably 1 mass % or more, more preferably 3 mass % or more, and still more preferably 5 mass % or more. In addition, the content rate is preferably 40 mass% or less, more preferably 35 mass% or less, still more preferably 30 mass% or less.

At least one of the polymers is preferably a copolymer containing a structural unit derived from a monomer having a nitrile group, more preferably a copolymer containing a structural unit derived from a (meth)acrylonitrile monomer. The polymer used together may be a homopolymer not containing a structural unit derived from a monomer having a nitrile group, or a copolymer not containing a structural unit derived from a monomer having a nitrile group.

In the copolymer containing a structural unit derived from a monomer having a nitrile group, the content rate of the structural unit derived from the monomer having a nitrile group is preferably 1 mass % or more, more preferably 3 mass % or more, and still more preferably It is 5 mass% or more. In addition, the content rate is preferably 40 mass% or less, more preferably 35 mass% or less, still more preferably 30 mass% or less.

The total content of structural units derived from monomer A in a copolymer containing structural units derived from a monomer having a nitrile group is preferably 50 mass % or more, more preferably 55 mass % or more, and still more preferably 60 Quality% or more. In addition, the total content rate is preferably 94 mass% or less, more preferably 92 mass% or less, and still more preferably 90 mass% or less.

The total content of structural units derived from monomer B1 in a copolymer containing structural units derived from a monomer having a nitrile group is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, and still more preferably 1.0 Quality % or more. In addition, the total content rate is preferably 30 mass% or less, more preferably 25 mass% or less, and still more preferably 20 mass% or less.

The total content of structural units derived from monomer A in a copolymer that does not contain structural units derived from a monomer having a nitrile group is preferably 70 mass % or more, more preferably 75 mass % or more, and still more preferably More than 80% by mass. In addition, the total content rate is preferably 99 mass% or less, more preferably 98 mass% or less, still more preferably 97 mass% or less.

The total content of structural units derived from monomer B1 in a copolymer that does not contain structural units derived from a monomer having a nitrile group is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, and still more preferably 1.0% by mass or more. In addition, the total content rate is preferably 30 mass% or less, more preferably 25 mass% or less, and still more preferably 20 mass% or less.

In at least two types of polymers, the difference in the proportion of structural units derived from (meth)acrylonitrile monomer is preferably 1 mass % or more, more preferably 3 mass % or more, and still more preferably 5 mass % above. The upper limit of the difference in the proportion of structural units derived from (meth)acrylonitrile monomer is not particularly limited, but is preferably 40 mass% or less, more preferably 35 mass% or less, and still more preferably 30 mass% the following.

Preferred combinations of two (meth)acrylic polymers include the following (I) and (II), with (I) being preferred. (I) Combination of nitrile group-containing (meth)acrylic acid polymer and nitrile group-free (meth)acrylic acid polymer (II) Both are nitrile group-containing (meth)acrylic polymers, and the content rates of structural units derived from (meth)acrylonitrile monomers are different from each other.

The number average molecular weight (Mn) of the polymer may be, for example, 1.0×10 ³ or more, or 1×10 ⁴ or more. In addition, for example, it may be 1.0×10 ⁶ or less, or it may be 5.0×10 ⁵ or less. The weight average molecular weight (Mw) of the polymer may be, for example, 1.0×10 ³ or more, or 1.0×10 ⁴ or more. In addition, for example, it may be 5.0×10 ⁶ or less, or it may be 1.0×10 ⁶ or less. The Mn and Mw of the polymer are measured by a common method using gel permeation chromatography (GPC).

The content rate of the most abundant polymer in the release layer is preferably 95 mass % or less, more preferably 90 mass % or less, and still more preferably 85 mass % or less relative to the total content of the polymer. If the content of the polymer with the largest content is 95% by mass or less, unevenness tends to be easily formed on the surface of the release film.

When the polymer is a cross-linked polymer, it is preferred to use a cross-linking agent. Examples of the cross-linking agent include known cross-linking agents such as isocyanate compounds, melamine compounds, and epoxy compounds. In addition, from the viewpoint of forming a slowly expanding network structure, the crosslinking agent is more preferably a multifunctional crosslinking agent such as a trifunctional or tetrafunctional crosslinking agent.

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

Examples of the difunctional isocyanate compound include aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, aromatic diisocyanate compounds, carbodiimide modified products of these diisocyanate compounds, and compounds having these diisocyanate compounds in their molecules. Polymer compounds, etc.

Examples of aliphatic diisocyanate compounds include 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), and trimethylhexamethylene diisocyanate. (trimethylhexamethylene diisocyanate, TMHDI), lysine diisocyanate, norbornane dimethyleneisocyanate (NBDI), etc.

Examples of alicyclic diisocyanate compounds include trans-cyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), and cyclohexane dimethylene diisocyanate. H6-XDI) (Hydrogenated xylylene diisocyanate, 4,4'-diisocyanate (diphenylmethane-4,4'-diisocyanate, MDI)), etc.

Examples of aromatic diisocyanate compounds include dimer diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), and 2,6-toluene diisocyanate (2,6-TDI). ), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), 1,5 -Naphthalene diisocyanate (1,5-naphthalene diisocyanate, NDI), etc.

Examples of the polyfunctional isocyanate compound include a trimer of a difunctional isocyanate compound, a polymer compound having a trimer of a difunctional isocyanate compound in the molecule, and the like. Examples of the trimer of the difunctional isocyanate compound include an isocyanurate body of the difunctional isocyanate compound, an adduct of the difunctional isocyanate compound, and a biuret body of the difunctional isocyanate compound.

The content of the crosslinking agent contained in the release layer may be, for example, 0.1 to 50 parts by mass, or 1 to 40 parts by mass relative to 100 parts by mass of the solid content of the polymer contained in the release layer.

The release layer may also contain an anchoring enhancer, a crosslinking accelerator, a colorant, an antistatic agent, etc. as needed. For example, when the release layer contains an antistatic agent, discharge is less likely to occur during peeling, and electrostatic damage to electronic components is suppressed.

The release layer preferably has a plurality of regions with different component ratios, and when Raman spectroscopy is measured in the various regions, different peak intensities are shown in at least a part of the different regions. In addition, it is preferable that the surface of the release layer has an uneven shape, and when Raman spectroscopy is measured in the convex portions and the concave portions, different peak intensities are shown in at least a part of the convex parts and at least a part of the concave parts. . As an example, polymer component ratios may be different in at least a part of different regions, or in at least a part of a convex part and at least a part of a recessed part. As a further specific example, it is preferable that the content of the nitrile group-containing (meth)acrylic polymer is different in at least a part of different regions, or in at least a part of a convex part and at least a part of a recessed part. In addition, the peak showing different peak intensities is preferably a peak derived from a nitrile group.

In the release layer, at least one region preferably contains a nitrile group-containing (meth)acrylic polymer, and the other region may contain a nitrile group-containing (meth)acrylic polymer, or it may not contain a nitrile group. of (meth)acrylic acid polymers. From the viewpoint of easily creating unevenness on the surface of the release layer, it is preferable that the nitrile group-containing (meth)acrylic polymer is not included in the other region. Furthermore, whether a nitrile group-containing (meth)acrylic polymer is not included in a region can be determined by analyzing the components of the region using the micro-Raman spectroscopy method described below. No spectrum corresponding to the nitrile group was detected. crest to confirm.

Regarding each region, when the surface of the release layer is planarly observed, a phase separation state occurs within the layer, and a continuous phase and a discontinuous phase can be formed. The area ratio of the continuous phase and the discontinuous phase can be adjusted by the compounding ratio of the polymer contained in the release layer. The polymer with a small content ratio in the release layer is included in the discontinuous phase, and the polymer with a large content ratio is included in the continuous phase.

Moreover, it is preferable that the surface of the release layer has an uneven shape, and the peak intensity derived from the nitrile group in at least a part of the convex part is greater than the peak intensity derived from the nitrile group in at least a part of the recessed part. Furthermore, it is preferable that the surface of the release layer has an uneven shape, and that the mass-based content of the nitrile group-containing (meth)acrylic polymer in at least a part of the convex parts is greater than that of the nitrile group-containing (meth)acrylic polymer in at least a part of the recessed parts. The (meth)acrylic acid polymer has a large mass content.

Raman spectroscopy equipment is used for Raman spectroscopy measurement in each area and uneven portion. As a Raman spectroscopy device, for example, "DXR2xi" manufactured by Thermo Fischer Scientific is used, and measurement is performed under the following conditions. ・Wavelength: 532 nm ・Power: 10 mW ・Exposure time: 0.05 seconds ・Number of scans: 1000 times ・Aperture: 25 μm pinhole ・Objective lens: 100x

The component ratio in each area and the uneven portion is measured by obtaining a spectrum of the portion irradiated with laser one by one using Raman spectroscopy. For example, for a specific component (such as nitrile group) constituting the release layer, the peak of the Raman spectrum is identified in advance, and based on its signal intensity, the relative content of the specific component at one location and another location is confirmed.

FIG. 2 is a photograph and an analysis chart of the surface of the release layer using a laser microscope. "VK-X3000" manufactured by Keyence Co., Ltd. was used as a laser microscope, and observation was performed with a 50x objective lens. In Figure 2, the laser microscope is used, but other laser microscopes can also be used on the surface of the release layer.

In Figure 2, sample G1 is a previous release layer containing a filler, and samples G2 and G3 use a combination of a (meth)acrylic polymer (polymer A) containing a nitrile group and a (methyl) polymer without a nitrile group. The release layer of the present disclosure is an acrylic polymer (Polymer B). Regarding sample G2, the content of polymer A in the total polymer was 15% by mass, and the content of polymer B was 85% by mass. Regarding sample G3, the content of polymer A in the total polymer was 85% by mass, and the content of polymer B was 15% by mass.

The first and second sections of Figure 2 are planar photographs of the surface of the release layer when viewed in plan. The third section of Figure 2 shows the concave and convex shapes of the surface on the straight line indicated by the arrow in the second section of the photograph. Analytical profile curve. As shown in FIG. 2 , in samples G2 and G3, the release layer is formed in a plurality of regions.

Regarding sample G2, the content rate of the nitrile group-containing (meth)acrylic polymer in the entire polymer is less than half. In this case, the area occupied by the convex portion in the entire surface is less than half. On the other hand, in sample G3, the content rate of the nitrile group-containing (meth)acrylic polymer in the entire polymer exceeds half. In this case, the area occupied by the convex portion exceeds half of the entire surface. From this, it can be seen that the content rate of the nitrile group-containing (meth)acrylic polymer is greater in the convex portions than in the concave portions.

Furthermore, as shown in FIG. 2 , in the previous sample G1, the filler was aggregated, so it was found that the uniformity of the shape, size, etc. of the convex portions was low.

Figure 3 is a spectrum result obtained by analyzing the components of the discontinuous phase (island phase, convex parts) and the continuous phase (marine phase, concave parts) in sample G2 in Figure 2 using micro-Raman spectroscopy. Here, the discontinuous phase refers to a region that occupies a small area on the observation surface, and the continuous phase refers to a region that occupies a large area on the observation surface.

In FIG. 3 , the peak derived from the nitrile group is detected in the discontinuous phase (convex portion), whereas the peak derived from the nitrile group is not detected in the continuous phase (concave portion). From this result, it can be seen that the component ratio of the polymer is different in the discontinuous phase (convex portions) and the continuous phase (concave portions). In addition, it is found that the content of the nitrile group-containing (meth)acrylic polymer is larger in the convex parts than in the concave parts.

Figure 4 is a spectrum result obtained by analyzing the components of the convex parts (marine phase, continuous phase) and concave parts (island phase, discontinuous phase) in sample G3 in Figure 2 using micro-Raman spectroscopy. The peak derived from the nitrile group was detected in the convex portion, whereas the peak derived from the nitrile group was not detected in the concave portion. From this result, it can be seen that the component ratio of the polymer is different between the convex portion and the concave portion. In addition, it is found that the content of the nitrile group-containing (meth)acrylic polymer is larger in the convex parts than in the concave parts. In FIG. 4 , a continuous phase is formed by containing more than 50% by mass of the nitrile group-containing (meth)acrylic polymer as a main component in the entire polymer, but this continuous phase forms convex portions. In FIG. 3 , the continuous phase forms a concave portion, whereas in FIG. 4 , the continuous phase is reversed. However, in both cases of FIGS. 3 and 4 , the nitrile group-containing (meth)acrylic polymer is contained in the convex portions more than in the concave portions.

Even if the discontinuous phase forms convex portions as shown in Fig. 3, the discontinuous phase may form concave portions as shown in Fig. 4. From the viewpoint of mold releasability, it is preferable that the discontinuous phase forms convex portions. When the surface of the release layer is observed planarly using a laser microscope, the proportion of the convex portions in the surface of the release layer is preferably 60 area % or less, more preferably 55 area % or less, and still more preferably 50 area %. %the following. In addition, the ratio of the convex portions in the surface of the release layer is preferably 5 area % or more, more preferably 10 area % or more, and still more preferably 15 area % or more.

In planar observation of the surface of the release layer, the maximum diameter of the convex portion is preferably 50 μm or less, more preferably 45 μm or less, and still more preferably 40 μm or less. As long as the release layer exhibits release properties, the lower limit of the maximum diameter of the convex portion is not particularly limited. For example, it may be 1 μm or more, 2 μm or more, or 5 μm or more. The maximum diameter of the convex part is the value when observed with a laser microscope in one field of view of 400 times. As shown in sample G1 of FIG. 2 , in the case of a conventional release film to which fillers are added, the fillers tend to agglomerate and the maximum diameter of the convex portions tends to become larger.

The maximum diameter of the convex part is a value obtained by measuring the diameter of the convex part with the largest diameter when observing with a laser microscope in one field of view of 400 times.

When the surface of the release layer is planarly observed using a laser microscope, the circularity of the convex portion is preferably 0.7 or more, more preferably 0.8 or more. "Circularity" is a value calculated using the following formula, and is an index indicating the complexity of the particle shape. The closer the circularity is to 1, the closer the particle shape is to a perfect circle. Circularity=4π×(Area)÷(Perimeter) ²

The circularity of the convex portion is the arithmetic mean value of the circularity measured for ten convex portions when observed with a laser microscope. The circularity of the convex portion can be calculated using known image analysis means if necessary.

As shown in sample G1 of FIG. 2 , in the case of a conventional release film to which fillers are added, the fillers tend to agglomerate and the roundness of the convex portions tends to decrease.

The thickness of the release layer is not particularly limited, but it is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more. If the thickness of the release layer is 1 μm or more, sufficient adhesion to electronic parts can be obtained and the intrusion of the sealing material can be effectively suppressed. The thickness of the release layer may be 50 μm or less, or 25 μm or less. When the thickness of the release layer is 50 μm or less, heat shrinkage stress is less likely to occur when the release layer is thermally cured, making it easier to maintain the flatness of the release film. In addition, when the release film has a conductive layer, the distance between the surface of the release layer and the conductive layer is not too far, the surface resistivity is maintained low, and electrostatic damage of electronic components can be effectively suppressed. Taking into account the ease of formation of the release layer (coatability, etc.), ensuring the adhesion, etc., the thickness of the release layer is preferably 1 μm to 50 μm, more preferably 3 μm to 25 μm.

From the viewpoint of maximizing the effect of the embodiment of the present disclosure, the release layer preferably does not contain a filler, but it may contain a filler. When a filler is used, it may be at least one of an organic filler and an inorganic filler. The content rate of the filler in the release layer can be, for example, 1 volume % or less, 0.5 volume % or less, or 0.1 volume % or less. The content rate (volume %) of the filler in the release layer can be calculated based on the density measured by Archimedes' method, the resin component, and the specific gravity of the filler.

(Elongation at break of release layer) The elongation at break of the release layer is 100% or more, preferably 120% or more, and more preferably 150% or more. The elongation at break of the release layer, for example, when the release layer contains at least one nitrile group-containing (meth)acrylic polymer, can be adjusted by the amount of the nitrile group-containing (meth)acrylic polymer. . The upper limit of the elongation at break of the release layer is not particularly limited, but may be, for example, 800% or less, 500% or less, or 300% or less.

The elongation at break (%) of the release layer of the release film is measured as follows. First, a release film was used to prepare a test piece having a shape as shown in Fig. 5 . The test piece was grasped at both ends with a testing machine and a tensile test was performed. The measurement was performed at 170°C, and the stretching speed was set to 200 mm/min. Based on the distance A between the marking points of the sample before the test (the length of the 10 mm wide part of the test piece shown in Figure 5: 40 mm) and the distance B between the marking points when the release layer breaks, the release layer is calculated by the following formula Elongation at break of the mold layer.

[Number 1]

For the measurement of the elongation at break of the release layer of the release film, for example, "Tensilon tensile testing machine RTA-100 model" manufactured by Orientec Co., Ltd., or A&D Co., Ltd. "Tensilon Universal Testing Machine RTG-1210" or a similar testing machine with a grabber.

(Surface roughness of release layer) The arithmetic mean roughness (Ra) of the outer surface of the release layer (the surface opposite to the surface facing the base material layer) is 0.2 μm or more, preferably 0.25 μm or more, more preferably 0.3 μm or more. The upper limit of the arithmetic mean roughness (Ra) is not particularly limited, but may be 2.5 μm or less, 2.0 μm or less, or 1.5 μm or less, for example.

The arithmetic mean roughness (Ra) of the outer surface of the release layer can be determined by JIS B0601 (1994) or International Standards Organization (ISO) 4287 (1997) using a surface roughness measuring device (e.g., Kosaka Laboratory (stock), Model SE-3500) was obtained by analyzing the results measured under the conditions of stylus tip diameter 2 μm, feed speed 0.5 mm/s, and scanning distance 8 mm. The arithmetic mean roughness (Ra) of the outer surface of the release layer can be determined by the blending ratio of the polymer contained in the release layer, the thickness of the release layer, the cross-linking amount when using a cross-linking agent, and the amount of cross-linking agent when using a catalyst. Adjust the catalyst amount, etc.

[Substrate layer] The base material layer is not particularly limited, and can be appropriately selected from base material layers used in this technical field. From the viewpoint of improving the ability to follow the shape of the mold, it is preferable to use a resin-containing base material layer that is excellent in extensibility. Considering the heating temperature used for molding the sealing material (approximately 100° C. to 200° C.), it is desirable that the base material layer has heat resistance higher than the heating temperature. In addition, from the viewpoint of suppressing the occurrence of wrinkles, cracks, etc. when the release film is mounted on the mold and when the sealing material flows, it is preferable to select the base material taking into account the elastic modulus, elongation, etc. during heating. layer material.

From the viewpoint of heat resistance and elastic modulus during heating, the material of the base layer is preferably polyester resin. Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, and copolymers and modified resins thereof.

The base material layer is preferably in a sheet shape, preferably a polyester resin molded into a sheet shape, more preferably a polyester film, and from the viewpoint of mold followability, the base layer is preferably biaxially stretched polyester. membrane.

The thickness of the base material layer is not particularly limited, but is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm. If the thickness is 5 μm or more, the workability will be excellent and wrinkles will tend to be less likely to occur. When the thickness is 100 μm or less, the mold followability during molding is excellent, so the occurrence of wrinkles and the like in the molded semiconductor package tends to be suppressed.

[Other structures] Depending on the material of the base material layer, it is preferably designed so that the release sheet can be easily peeled off from the mold. For example, the opposite surface of the base layer that is in contact with the release layer, that is, the surface of the base layer on the mold side may be subjected to surface processing such as pear peel processing, or another release layer (second release layer) may be provided. . The material of the second release layer is not particularly limited as long as it satisfies peelability from the mold, heat resistance, etc., and the same material as the release layer (hereinafter also referred to as "specific release layer") can be used. Same material. The thickness of the second release layer is not particularly limited, but is preferably 0.1 μm to 100 μm.

Furthermore, if necessary, an anchoring improvement layer, an antistatic layer, a colored layer, etc. may be provided between a specific release layer and the base material layer, between the base material layer and the second release layer, or the like.

＜Manufacturing method of release film＞ The release film of this disclosure can be produced by a known method. For example, the release film of this disclosure can be manufactured by applying a composition for forming a release layer to a base material layer and drying it. The composition for forming a release layer includes at least two polymers, and may further include other resin components and other components added as needed.

[Preparation of composition for forming release layer] The preparation method of the composition for forming a release layer is not particularly limited, and a known composition preparation method can be used. The solvent used in preparing the composition for forming a release layer is not particularly limited, but an organic solvent capable of dissolving the polymer is preferred. Examples of the organic solvent include toluene, methyl ethyl ketone, ethyl acetate, and the like.

[Giving and drying] The method of applying the composition for forming a release layer to the base material layer is not particularly limited, and known coating methods such as roll coating, bar coating, and die coating can be used. The amount of the composition for forming a release layer is preferably adjusted appropriately so that the thickness of the composition layer formed after drying is close to the thickness of the target release layer (for example, 1 μm to 50 μm). The method for drying the provided release layer forming composition is not particularly limited, and a known drying method can be used. For example, a method of drying at 50°C to 150°C for 0.1 to 60 minutes may be used.

＜Use of release film＞ The release film of this disclosure is used when sealing a semiconductor wafer with a sealing material. The release film of the present disclosure is preferably used in transfer molding or compression molding.

By using the release film of the present disclosure, the semiconductor package (molded article) can be easily removed from the mold while suppressing damage to the semiconductor package. In addition, by using the release film of the present disclosure, flow marks of the sealing material are suppressed on the surface of the semiconductor package (molded article), and the uniformity of the appearance is excellent. Furthermore, even when the release film is used in a situation where stretchability is required, breakage of the release layer can be suppressed. Therefore, even in this use form, it is possible to easily remove the mold from the mold while suppressing damage to the semiconductor package. Take out the semiconductor package (molded product).

＜Manufacturing method of semiconductor package＞ In the manufacturing method of a semiconductor package of the present disclosure, the transfer molding step or the compression molding step is performed using the release film of the present invention.

In a method of manufacturing a semiconductor package, first, the release film of the present disclosure is placed on a mold of a molding device so that the release film follows the shape of the mold. Examples of a method for making the release film follow the shape of the mold include vacuum adsorption.

Then, the semiconductor wafer is sealed with a sealing material in the mold followed by the release film. A semiconductor package can be manufactured by sealing the semiconductor wafer with a sealing material while the semiconductor wafer and the release film are arranged in the mold. After the semiconductor package is manufactured, the mold is opened and the molded semiconductor package is taken out.

In the manufacturing method of the semiconductor package of the present disclosure, since the release film of the present disclosure is used, flow marks of the sealing material on the surface of the semiconductor package are suppressed, and a semiconductor package excellent in appearance uniformity can be obtained. Furthermore, even if the release film is used under a condition requiring stretchability, breakage of the release layer can be suppressed. Therefore, the semiconductor package can be easily removed from the mold while suppressing damage to the semiconductor package.

Examples of the semiconductor wafer used in the method include semiconductor elements, capacitors, terminals, and the like. The type of sealing material used in the method is not particularly limited, and examples thereof include resin compositions containing epoxy resin, acrylic resin, and the like. [Example]

Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to these examples.

(Synthesis of synthetic resin 1 to synthetic resin 4) The monomers shown in Table 1 below were copolymerized by solution polymerization using the blending amounts (parts by mass) shown in Table 1, to obtain synthetic resins 1 to 4. For the obtained synthetic resins 1 to 4, the number average molecular weight Mn and the weight average molecular weight Mw were measured in terms of standard polystyrene by gel permeation chromatography (GPC). Table 1 shows the SP values of the obtained synthetic resins 1 to 4.

[Table 1] monomer synthetic resin 1 Synthetic resin 2 Synthetic resin 3 Synthetic resin 4 BA 92 0 88 71 4-HBA 8 0 0 0 MMA 0 59 0 0 2-HEA 0 28 0 0 2-HEMA 0 13 1 5 AN 0 0 11 twenty four Mn 144,000 56,000 140,000 140,000 Mw 854,000 120,000 910,000 610,000 SP value 10.0 10.2 10.3 11.0

The monomers in Table 1 represent the following. ・BA: Butyl acrylate ・4-HBA: 4-hydroxybutyl acrylate ・MMA: Methyl methacrylate ・2-HEA: 2-hydroxyethyl acrylate ・2-HEMA: 2-hydroxyethyl methacrylate ・AN: Acrylonitrile

<Example 1> Coronate L (Coronate L (Japan Polyurethane Industry) as a cross-linking agent) was used as a cross-linking agent relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (85 parts by mass) and synthetic resin 3 (15 parts by mass). (Co., Ltd., trade name) was added to toluene to prepare a toluene solution with a solid content of 15% by mass, thereby preparing a release layer forming composition. As the base material layer, a biaxially stretched polyethylene terephthalate film (Unitika Co., Ltd.: S-38) with a thickness of 38 μm was used, and corona treatment was performed. Then, a release layer-forming composition was applied to one side of the base material layer using a roll coater so that the average thickness after drying became 20 μm, and dried to form a release layer, thereby obtaining a release film.

<Example 2> A release film was produced in the same manner as in Example 1 except that the average thickness after drying of the release layer was 10 μm.

<Example 3> A release film was produced in the same manner as in Example 1 except that the average thickness after drying of the release layer was 5 μm.

<Example 4> A release film was produced in the same manner as in Example 3, except that synthetic resin 1 (90 parts by mass) and synthetic resin 3 (10 parts by mass) were used.

<Example 5> A release product was produced in the same manner as in Example 3 except that the crosslinking agent was 10 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (80 parts by mass) and synthetic resin 3 (20 parts by mass). mold film.

<Example 6> A debonding product was produced in the same manner as in Example 3 except that the crosslinking agent was 30 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (80 parts by mass) and synthetic resin 3 (20 parts by mass). mold film. <Example 7> A release film was produced in the same manner as in Example 3, except that synthetic resin 1 (50 parts by mass) and synthetic resin 3 (50 parts by mass) were used.

<Example 8> A release film was produced in the same manner as in Example 3, except that synthetic resin 1 (20 parts by mass) and synthetic resin 3 (80 parts by mass) were used.

<Example 9> A release film was produced in the same manner as in Example 3, except that synthetic resin 1 (10 parts by mass) and synthetic resin 3 (90 parts by mass) were used.

<Example 10> A release film was produced in the same manner as in Example 3, except that synthetic resin 1 (80 parts by mass) and synthetic resin 4 (20 parts by mass) were used.

<Example 11> A release product was produced in the same manner as in Example 3 except that the crosslinking agent was 30 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (80 parts by mass) and synthetic resin 4 (20 parts by mass). mold film.

<Example 12> A debonding product was produced in the same manner as in Example 3 except that the crosslinking agent was 20 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (50 parts by mass) and synthetic resin 4 (50 parts by mass). mold film.

<Example 13> A debonding product was produced in the same manner as in Example 3 except that the crosslinking agent was 20 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (20 parts by mass) and synthetic resin 4 (80 parts by mass). mold film.

<Example 14> A debonding product was produced in the same manner as in Example 3 except that the crosslinking agent was 2.2 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 3 (22 parts by mass) and synthetic resin 4 (78 parts by mass). mold film.

＜Comparative example 1＞ A debonding product was produced in the same manner as in Example 3 except that the crosslinking agent was 10 parts by mass relative to 100 parts by mass of the total compounding amount of synthetic resin 1 (80 parts by mass) and synthetic resin 2 (20 parts by mass). mold film.

＜Comparative example 2＞ The crosslinking agent was set to 40 parts by mass relative to synthetic resin 2 (100 parts by mass), and the filler MX-500 (trade name, Soken Chemical Co., Ltd., acrylic particles, average particle diameter 5 μm) was set to 15 parts by mass, a release film was produced in the same manner as in Example 3, except for this.

＜Comparative Example 3＞ A release film was produced in the same manner as in Example 3 except that the crosslinking agent was 10 parts by mass relative to synthetic resin 1 (100 parts by mass).

＜Comparative Example 4＞ A release film was produced in the same manner as in Example 3 except that the crosslinking agent was 20 parts by mass relative to synthetic resin 3 (100 parts by mass).

＜Evaluation test＞ (Surface roughness of release layer (Ra)) By the above method, the surface roughness (Ra) of the release layer of the release film is measured. "Surface roughness measuring instrument SE-3500" manufactured by Kosaka Laboratory Co., Ltd. was used for the measurement. The results are shown in Table 2.

(Elongation at break of release layer) By the above method, the elongation at break of the release layer of the release film is measured. The "Tensilon tensile testing machine RTA-100 model" manufactured by Orientec Co., Ltd. was used for the measurement. The results are shown in Table 2.

(Evaluation of mold releasability relative to epoxy molding compound (EMC)) As an index of the releasability of the release film from the sealing material after molding, the peeling force in a peeling test at a peeling angle of 180° and a peeling speed of 1000 mm/min was measured. The results were evaluated based on the following criteria. The results are shown in Table 2.

-Evaluation criteria- A: Less than 150 mN/50 mm B: 150 mN/50 mm or more and less than 250 mN/50 mm C: 250 mN/50 mm or more

(Evaluation of release layer breakage) Attach a stainless steel (Stainless Steel, SUS) plate (width 50 mm, thickness 0.6 mm) to the base material layer side of the release film. Arrange Teflon (registered trademark) on the release layer side, and spread a sealing material (Showa Denko Materials Co., Ltd.: trade name "CEL-9750ZHF10") between the release layer and Teflon. Furthermore, heating and pressure processing at 170° C. and 12.6 MPa was performed for 5 minutes so that the release layer side of the release film came into contact with the sealing material. The molded package is cut using a "desktop manual cutting machine KPS-4002" manufactured by Sun Advance Co., Ltd. and cast with epoxy resin. The cast package was polished using polishing paper with particle sizes of P800, 1500, and 2200 to expose the cross section. The package cross section after polishing was observed using a "digital microscope VHX-7000" manufactured by Keyence Co., Ltd. to confirm whether the release layer was broken. The results are shown in Table 2.

(evaluation of flow marks) A sealing material (Showa Denko Materials Co., Ltd.: trade name "CEL-9750ZHF10") was attached to the release layer side of the release film, and heat and pressure processing was performed at 180°C and 32 MPa for 5 minutes. Observe the processed package visually to confirm whether there are any flow marks caused by the packaging material. The results are shown in Table 2.

[Table 2] synthetic resin Cross-linking agent filler Thickness (μm) Ra (μm) Elongation at break (%) Mold releasability Breakage of release layer Flow marks 1 2 3 4 Example 1 85 15 20 20 1.5 110 A without without Example 2 85 15 20 10 1.2 130 A without without Example 3 85 15 20 5 1.0 170 A without without Example 4 90 10 20 5 0.3 160 A without without Example 5 80 20 10 5 0.5 180≦ A without without Example 6 80 20 30 5 0.6 150 A without without Example 7 50 50 20 5 1.2 170 A without without Example 8 20 80 20 5 0.4 180≦ B without without Example 9 10 90 20 5 0.3 180≦ B without without Example 10 80 20 20 5 0.3 170 A without without Example 11 80 20 30 5 0.3 160 A without without Example 12 50 50 20 5 0.4 180≦ A without without Example 13 20 80 20 5 0.2 180≦ A without without Example 14 twenty two 78 2.2 5 0.2 180≦ B without without Comparative example 1 80 20 10 5 0.1 180≦ A without have Comparative example 2 100 40 15 5 0.4 80 B have without Comparative example 3 100 10 5 0.1 100 A without have Comparative example 4 100 20 5 0.1 180≦ C without have

The numerical values of synthetic resin, cross-linking agent, and filler in Table 2 represent the compounding amounts (parts by mass).

As shown in the results of Table 2, the release films of Examples 1 to 14 have an Ra that is equal to or greater than that of the release film of Comparative Example 2 containing a filler, and have an uneven shape on the surface. As shown in the results of Table 2, the release films of Examples 1 to 14 had no breakage of the release layer and the evaluation of flow marks was also good compared with the release films of Comparative Examples 1 to 4.

10:Substrate layer 20: Release layer 30: Release film

FIG. 1 is a schematic cross-sectional view showing the structure of a release film. FIG. 2 is a photograph and an analysis chart of the surface of the release layer using a laser microscope. Figure 3 is a spectrum result obtained by analyzing the components of the discontinuous phase (convex portions) and the continuous phase (concave portions) in sample G2 in Figure 2 using micro-Raman spectroscopy. Figure 4 is a spectrum result obtained by analyzing the components of the discontinuous phase (concave portions) and the continuous phase (convex portions) in sample G3 in Figure 2 using micro-Raman spectroscopy. FIG. 5 is a plan view showing the shape of a test piece used for measuring the elongation at break of the release film.

10:Substrate layer

20: Release layer

30: Release film

Claims (16)

A release film, including a release layer and a base material layer, The elongation at break of the release layer is 100% or more, and the surface roughness Ra of the release layer is 0.2 μm or more. The release film according to claim 1, wherein the release layer contains two or more polymers, The difference in solubility parameter values of at least two of said polymers is more than 0.3. The release film according to claim 1, wherein the release layer contains two or more polymers, At least one of the polymers is a nitrile group-containing (meth)acrylic acid polymer. The release film according to claim 1, wherein the release layer contains two or more polymers, and the two or more polymers have structural units derived from (meth)acrylyl monomers. of (meth)acrylic acid polymers. The release film as described in claim 1 satisfies at least one of the following (1) or (2): (1) The release layer has multiple regions with different component ratios, and when Raman spectroscopy is measured in the different multiple regions, different peak intensities are shown in at least a part of the different multiple regions; (2) The surface of the release layer has an uneven shape, and when Raman spectroscopy is measured in the convex portions and the concave portions, different peak intensities are shown in at least a part of the convex parts and at least a part of the concave parts. . The release film according to claim 5, wherein the component ratio of the polymer is different in at least a part of the different plurality of regions, or in at least a part of the convex part and at least a part of the recessed part. The release film according to claim 5, wherein in at least a part of the different regions, or in at least a part of the convex part and the recessed part, nitrile group-containing (methyl ) acrylic polymer content varies. The release film according to claim 5, wherein the peaks showing the different peak intensities are peaks derived from a nitrile group. The release film according to claim 5, wherein the surface of the release layer has an uneven shape, and the intensity of the peak originating from the nitrile group in at least a part of the convex part is higher than that of the peak originating from the nitrile group in at least a part of the concave part. The peak intensity of self-nitrile group is high. The release film according to claim 5, wherein the surface of the release layer has an uneven shape, and the nitrile group-containing (meth)acrylic polymer in at least a part of the convex portion has a mass-based The content is greater than the mass-based content of the nitrile group-containing (meth)acrylic polymer in at least a part of the recessed portion. The release film according to claim 1, wherein the release layer contains two or more polymers, at least one of the polymers is a polymer comprising structural units derived from (meth)acrylonitrile monomer, In at least two types of the polymers, the difference in the proportions of structural units derived from (meth)acrylonitrile monomer is 1 mass % or more. The release film according to claim 1, wherein the content rate of the most abundant polymer in the release layer is 95 mass % or less relative to the total content of the polymer. The release film according to claim 1, wherein the base material layer is a polyester film. The release film according to claim 1, wherein the thickness of the release layer is 1 μm to 50 μm. The release film according to claim 1, wherein the release film is used for transfer molding or compression molding. A manufacturing method of a semiconductor package, using the release film according to any one of claims 1 to 15 to perform a transfer molding step or a compression molding step.

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