KR20240015042A - Release film and method of producing semiconductor package - Google Patents

Abstract

[Problem] To provide a release film that can effectively reduce the glossiness of the surface of a semiconductor package, and a method of manufacturing a semiconductor package using this release film.
[Solution] A release layer comprising a release layer and a base layer, wherein the release layer includes two or more types of polymer, the surface of the release layer has a concavo-convex shape, and satisfies at least one of (1) to (3). It's a film. (1) When the surface of the release layer is observed flat, the ratio of concave portions on the surface is 50 area% or less. When the uneven shape of the mold release layer is transferred to the molded product, (2) the percentage (transfer ratio) of the arithmetic average roughness (Ra) of the surface of the molded product to the arithmetic average roughness (Ra) of the surface of the molded product is 100% or more, (3) The glossiness (20°) of the surface of the molded product is 8.0 or less.

Description

Manufacturing method of release film and semiconductor package {RELEASE FILM AND METHOD OF PRODUCING SEMICONDUCTOR PACKAGE}

[0001] The present invention relates to a method of manufacturing a release film and a semiconductor package.

[0002] Semiconductor chips are usually sealed with resin for shielding and protection from outside air, and are mounted on a substrate as a molded product called a package. Molded articles are produced by injecting a sealant containing resin into a mold. A plurality of cavities are formed in the mold, and the plurality of cavities are connected through runners that serve as flow paths for the sealing material. In order to make it easier for the molded product to be released from the mold, methods such as mold structure and addition of a mold release agent to the seal resin are being devised.

[0003] Meanwhile, from requests for package miniaturization and multi-pin design, Ball Grid Array (BGA) method, Quad Flat Non-leaded (QFN) method, wafer level Chip Size Package (WL-CSP) method Package methods such as these are increasing. In the QFN method, to ensure standoff and prevent the generation of burrs due to the sealing material in the terminal part, and in the BGA method and WL-CSP method, to improve the release property of the package from the mold, A resin-made release film is placed inside a mold along the mold, and a sealing material is injected into the mold for molding (for example, see Patent Document 1). The method of molding using a release film is called the “film assist molding method.”

[0004] 1. Japanese Patent Publication No. 2002-158242

[0005] When the above-mentioned release film is used, flow marks of the sealing material may remain on the surface of the molded package, and the appearance may deteriorate. To reduce flow marks, measures such as adding a filler to the release layer of the release film can be considered. However, these measures are not sufficient, and additional reduction of flow marks is required. In order to reduce flow marks on the package surface, it is effective to reduce the glossiness of the package surface.

[0006] In consideration of these circumstances, the present disclosure aims to provide a release film that can effectively reduce the glossiness of the surface of a semiconductor package, and a method of manufacturing a semiconductor package using this release film.

[0007] Means for solving the above problems include the following embodiments.

<1> Includes a release layer and a base layer,

The release layer includes two or more types of polymers, and the surface of the release layer has a concavo-convex shape,

A release film in which the ratio of concave portions to the surface of the release layer when observed flat is 50 area% or less.

<2> Includes a release layer and a base layer,

The release layer includes two or more types of polymers, and the surface of the release layer has a concavo-convex shape,

The transfer rate, which is the percentage of the arithmetic average roughness (Ra) of the surface of the molded product when the uneven shape of the molded product is transferred to the molded product relative to the arithmetic average roughness (Ra) of the surface of the molded release layer, is 100. % or more release film.

<3> Includes a release layer and a base layer,

The release layer includes two or more types of polymers, and the surface of the release layer has a concavo-convex shape,

A release film wherein the glossiness (20°) of the surface of the molded product when the uneven shape of the release layer is transferred to the molded product is 8.0 or less.

<4> The release film according to any one of <1> to <3>, wherein at least one type of the polymer is a nitrile group-containing (meth)acrylic polymer.

<5> Any one of <1> to <4>, which shows different peak intensities in at least part of the convex part and at least part of the concave part when Raman spectroscopic measurement is performed on the unevenness of the surface of the release layer. Release film.

<6> The release film according to any one of <1> to <5>, wherein the component ratio of the polymer in the convex portion of the surface of the release layer is different from the component ratio of the polymer in the concave portion.

<7> The mass-based content of the nitrile group-containing (meth)acrylic polymer in the convex portion is greater than the mass-based content of the nitrile group-containing (meth)acrylic polymer in the concave portion. The release film described in .

<8> The release film according to any one of <1> to <7>, wherein at least two of the polymers have a SP value difference of 0.3 or more.

<9> At least one of the above polymers is a polymer containing a structural unit derived from a (meth)acrylonitrile monomer,

The release film according to any one of <1> to <8>, wherein at least two of the polymers have a difference in proportions of structural units derived from (meth)acrylonitrile monomers of 1% by mass or more.

<10> The release film according to any one of <1> to <9>, wherein the content of the polymer with the highest content in the release layer is 95% by mass or less with respect to the total content of the polymer.

<11> The release film according to any one of <1> to <10>, wherein the base material layer is a polyester film.

<12> The release film according to any one of <1> to <11>, wherein the release layer has a thickness of 1 μm to 50 μm.

<13> The release film according to any one of <1> to <12>, wherein the release film is used for transfer molding or compression molding.

<14> A method of manufacturing a semiconductor package, comprising performing a transfer molding process or a compression molding process using the release film according to any one of <1> to <13>.

[0008] According to the present disclosure, a release film capable of effectively reducing the glossiness of the surface of a semiconductor package and a method of manufacturing a semiconductor package using the release film are provided.

[0009] Figure 1 is a schematic cross-sectional view showing the structure of a release film.
Figure 2 is a photograph and analysis graph of the surface of the release layer using a laser microscope.
Figure 3 shows microscopic images of the discontinuous phase (island phase, convex portion) and the continuous phase (sea phase, concave portion) in sample G2 in Fig. 2. This is the spectrum result of component analysis using Raman spectroscopy.
FIG. 4 shows the spectrum results of component analysis by micro-Raman spectroscopy for the discontinuous phase (island phase, concave portion) and continuous phase (resolution, convex portion) in sample G3 in FIG. 2.
Figure 5 is a plan view showing the shape of a test piece used to measure the breaking elongation of the release film.

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

[0011] In the present disclosure, the word “process” includes not only processes that are independent from other processes, but also processes that are independent from other processes, as long as the purpose of the process is achieved, even if the process cannot be clearly distinguished from other processes.

In the present disclosure, the numerical range indicated using “~” includes the numerical values written before and after “~” as the minimum and maximum values, respectively.

In the numerical range described stepwise during the present disclosure, the upper or lower limit value described as one numerical range may be replaced with the upper limit or lower limit value of another numerical range described stepwise. In addition, in the numerical range described in the present disclosure, the upper or lower limit of the numerical range may be replaced with the value shown in the examples.

In the present disclosure, each component may contain multiple types of corresponding substances. When multiple types of substances corresponding to each component exist in the composition, the content rate or content of each component means the total content rate or content of the multiple types of materials present in the composition, unless otherwise specified.

In the present disclosure, the word “layer” includes not only the case where the layer is formed in the entire area when observing the area where the layer exists, but also the case where the layer is formed only in a part of the area.

[0012] In the present disclosure, the thickness of the release film or each layer constituting the release film can be measured by a known method. For example, the measurement may be performed using a dial gauge or the like, or may be measured from 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 from the mass before and after removal, the density of the material, the area of the layer, etc. If the thickness of the layer is not constant, the arithmetic average of the values measured at five random points (five points) is taken as the thickness of the layer.

In the present disclosure, “(meth)acrylic” means either or both of acrylic and methacrylate, and “(meth)acrylate” means either acrylate or methacrylate. It means both, and “(meth)acryloyl” means either or both of acryloyl and methacryloyl.

In the present disclosure, when an embodiment is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Additionally, the sizes of members in each drawing are conceptual, and the relative size relationship between members is not limited to this.

[0013] <Release Film>

The release film of the present disclosure includes a release layer and a base layer, wherein the release layer includes two or more types of polymers, the surface of the release layer has a concavo-convex shape, and at least one of the following (1) to (3): It is a release film that satisfies the requirements.

(1) When the surface of the release layer is observed flat, the ratio of concave portions on the surface is 50 area% or less.

(2) The transfer rate, which is the percentage of the arithmetic average roughness (Ra) of the surface of the molded product when the uneven shape of the molded product is transferred to the arithmetic average roughness (Ra) of the surface of the mold release layer, is 100% or more.

(3) When the uneven shape of the release layer is transferred to the molded product, the glossiness (20°) of the surface of the molded product is 8.0 or less.

The release film of the present disclosure employing the above configuration can effectively reduce the glossiness of the surface of the molded semiconductor package. Although the reason is not clear, it is assumed as follows. In addition, the release film of this disclosure is not limited at all by the following speculation.

[0014] In the release film of the present disclosure, the release layer includes two or more types of polymers, thereby forming an uneven shape on the surface of the release layer. For example, when the release layer has multiple types of regions where the polymer component ratios are different, in one region, the polymers may aggregate together, increase density, and partially swell, forming an uneven shape on the surface of the release layer. The surface of the release layer may have a concave-convex shape, and the component ratio of the polymer in the convex portion may be different from the component ratio of the polymer in the concave portion. Accordingly, the release film of the present disclosure can generate irregularities on the surface of the release film without adding filler to the release layer.

[0015] In the present disclosure, “polymer” refers to a high molecular weight component that does not contain an organic filler. Here, the organic filler is insoluble or poorly soluble in organic solvents (such as toluene, methyl ethyl ketone, and ethyl acetate) that can be used in adjusting the composition for forming a release layer. Here, insolubility or poor solubility in organic solvents means that in a gel fraction test based on JIS K6769 (2013), the gel fraction after dispersing resin particles in an organic solvent such as toluene and maintaining it at 50°C for 24 hours is 97% by mass. It says something more than that.

In the present disclosure, “different types of polymers” means that the types of constituting monomers are different, or the types of constituting monomers are the same, but the content of structural units derived from at least one type of monomer is 1% by mass or more. It says different things.

[0016] As one of the specific methods of forming a plurality of regions with different polymer component ratios, it is preferable to use two or more types of polymers with a difference in SP value of 0.3 or more. Polymers with a difference in SP value of 0.3 or more tend to separate from each other because their compatibility is low, and polymers of the same type tend to aggregate together to form uneven shapes on the surface of the release layer. In particular, when at least one type of polymer is a nitrile group-containing (meth)acrylic polymer, the nitrile group-containing (meth)acrylic polymers tend to aggregate together to form convex portions.

[0017] Additionally, when Raman spectroscopic measurement is performed on the convex portion and the concave portion, it is preferable that at least a portion of the convex portion and at least a portion of the concave portion exhibit different peak intensities. Showing different peak intensities when Raman spectroscopic measurement is performed on at least part of the convex part and at least part of the concave part means different peak intensities when Raman spectroscopic measurement is performed on at least part of the convex part and at least part of the concave part. Anything that shows intensity is sufficient. In the case of having a plurality of convex portions, the peak intensities of each convex portion may be the same or different. In the case of having a plurality of recessed parts, the peak intensities of each recessed part may be the same or different.

In the present disclosure, “different peak intensities are shown when Raman spectroscopy measurement is performed” means that the intensity of a peak appearing at a certain position in a Raman spectrum obtained by Raman spectroscopic measurement is different, and the peak intensity at a certain position is different. Differences in the presence or absence of peaks are also included in differences in peak intensity.

[0018] In a conventional release film, filler is added to the release layer to generate irregularities on the surface of the release layer to reduce flow marks of the seal material on the surface of the semiconductor package. In such a conventional release film, the filler is shaped to protrude from the surface of the release layer, so that the bottom of the concave portion corresponds to the surface of the release layer before adding the filler, and the bottom of the concave portion is flat. Since the uneven shape of the surface of the release layer is transferred to the seal molded product on the surface of the semiconductor package, the apex of the convex portion formed on the surface of the semiconductor package becomes flat. Therefore, on the surface of a semiconductor package on which a convex portion with a flat peak is formed, the gloss is not sufficiently reduced.

[0019] On the other hand, in the release film of the present disclosure, the release layer forms an uneven shape on the surface of the release layer by two or more types of polymers, and the ratio of concave portions on the surface of the release layer is 50 area% or less, The bottom of the concave part has a pointed end. The reason is not clear, but it is presumed that polymers of the same type aggregate and contract to form depressions as if they are being pulled together. On the surface of the semiconductor package to which the shape of the surface of the release film of the present disclosure has been transferred, the apex of the convex portion becomes sharp, effectively reducing the glossiness of the surface of the semiconductor package.

In addition, the release film of the present disclosure is not limited to the bottom of the concave portion being sharp at an acute angle, and may be an obtuse angle, may be curved, or the bottom of the concave portion may be partially flat. The shape of the concave portion may be formed by a combination of these. Additionally, among the plurality of recesses, the bottoms of some of the recesses may be flat.

[0020] Therefore, when the release layer contains two or more types of polymers, the uneven shape of the release layer of the release film is transferred to the molded product, (2) the arithmetic mean roughness (Ra) of the surface of the release layer, It is possible for the transfer rate, which is the percentage of the arithmetic average roughness (Ra) of the surface, to be 100% or more, and (3) the glossiness (20°) of the surface of the molded product to be 8.0 or less.

[0021] In addition, since the release film of the present disclosure can form an uneven shape on the surface even without adding filler, it is possible to suppress the occurrence of problems such as peeling off of the filler. In addition, in a conventional release film, the release layer tends to break starting from the filler, but in the release film of the present disclosure, it is also possible to suppress breakage of the release layer. Additionally, the extensibility of the release layer is also excellent. The extensibility of the release layer is excellent, and the release film has excellent followability to the mold. Additionally, when fracture of the mold release layer is suppressed, contact of the seal material with the mold at the fractured portion is suppressed, and the extractability of the molded product from the mold is excellent.

[0022] In the release film of the present disclosure, since an uneven shape can be formed on the surface without adding filler, it is also possible to form a convex portion where a clear interface cannot be observed. A convex portion in which a clear interface is not confirmed refers to a particle interface in the same manner as in the case where a filler is added, when observed with a laser microscope.

[0023] As an example of the release film of the present disclosure, Figure 1 schematically shows the cross-sectional configuration of the release film. 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 have other layers. Other layers include a second release layer, an anchoring improvement layer, an antistatic layer, and a colored layer.

[0024] [Heterogeneous layer]

The release layer contains at least two polymers.

The difference in SP values of at least two types of 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.

[0025] In the present disclosure, when there are two types of polymers included in the release layer, the difference in SP values refers to the difference in SP values between each polymer. When there are three or more types of polymers included in the release layer, the difference in SP values refers to the difference in SP values between the polymer with the highest SP value and the polymer with the lowest SP value among the polymers included in the release layer.

[0026] The SP value is a solubility parameter derived from the partial structural unit of the chemical structural formula, and is a value obtained by the Fedors method.

[0027] The type of polymer is not particularly limited, and is preferably selected taking into account the adhesiveness, release properties, heat resistance, etc. of the release layer. Specifically, polymers include (meth)acrylic polymer, silicone, and urethane polymer, which have structural units derived from (meth)acryloyl monomer. It is preferable that at least one type of polymer is a (meth)acrylic polymer, and it is more preferable to use two or more types of (meth)acrylic polymer.

[0028] The proportion of the (meth)acrylic polymer in the total polymer is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, 80% by mass or more, 85% by mass. Above, it may be 90 mass% or more, or 95 mass% or more. The upper limit is not particularly limited, and the ratio may be 100 mass%, 95 mass% or less, 90 mass% or less, and 85 mass% or less.

[0029] The (meth)acrylic polymer may be a homopolymer or a copolymer, or a combination of a homopolymer and a copolymer may be used. It is preferable that at least one type of (meth)acrylic polymer is 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.

[0030] Monomer A is preferably a monomer with a relatively low glass transition temperature (Tg) (eg, -20°C or lower). In addition, a monomer with a relatively low Tg refers to a monomer that has a relatively low glass transition temperature when a homopolymer is synthesized from the monomer. Examples of monomer A include butyl (meth)acrylate, ethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The copolymer may contain structural units derived from monomer A individually, or may contain them in combination of two or more types.

[0031] When the copolymer contains structural units derived from monomer A, the total content of structural units derived from monomer A in the copolymer is preferably more than 50% by mass, and more preferably 55% by mass or more. It is preferable, and it is more preferable that it is 60 mass % or more. Moreover, the total content is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less.

[0032] At least one type of polymer is preferably a copolymer containing structural units derived from monomer B having a functional group. Functional groups include carboxylic acid groups, hydroxyl groups, amide groups, and nitrile groups. The functional group may be a crosslinkable functional group or a non-crosslinkable functional group. Examples of crosslinkable functional groups include carboxylic acid groups, hydroxyl groups, and amide groups, and examples of non-crosslinkable functional groups include nitrile groups. The copolymer may contain structural units derived from monomer B individually or in combinations of two or more types. It is more preferable that at least one type of polymer is a nitrile group-containing (meth)acrylic polymer.

[0033] The crosslinked polymer having a crosslinkable functional group may be at least partially crosslinked and included in the release film. In this disclosure, even when two or more types of polymers are crosslinked, the release film is included in a form containing two or more types of polymers.

[0034] When the polymer is crosslinked, it is possible to analyze or estimate the polymer before crosslinking by decomposing the bonds at the crosslinking points. For example, when the polymer has a hydroxyl group and an isocyanate compound is used as a crosslinking agent, it is assumed that the polymer is crosslinked by forming a urethane bond, and the urethane bond can be selectively decomposed by pyridine.

[0035] The crosslinked polymer is preferably a crosslinked (meth)acrylic polymer, and more preferably is a crosslinked (meth)acrylic copolymer.

[0036] Examples of monomer B1 having a crosslinkable functional group include (meth)acrylic acid, hydroxyethyl (meth)acrylate, hydroxyethyl (meth)acrylate, and (meth)acrylamide. Examples of monomer B2 having a non-crosslinkable functional group include (meth)acrylonitrile.

[0037] The total content of structural units derived from monomer B1 of at least one type of polymer is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and even more preferably 1.0 mass% or more. Moreover, the total content is preferably 30 mass% or less, more preferably 25 mass% or less, and even more preferably 20 mass% or less.

[0038] At least one type of polymer preferably has a total content of structural units derived from monomer B2 of 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. Moreover, the content is preferably 55 mass% or less, more preferably 50 mass% or less, and even more preferably 45 mass% or less.

[0039] At least one type of polymer is preferably a copolymer containing a structural unit derived from a monomer having a nitrile group, and more preferably a copolymer containing a structural unit derived from a (meth)acrylonitrile monomer. The polymer used in combination may be a homopolymer containing no structural units derived from a monomer having a nitrile group, or a copolymer containing no structural units derived from a monomer having a nitrile group.

[0040] In a copolymer containing a structural unit derived from a monomer having a nitrile group, the content of the structural unit derived from a monomer having a nitrile group is preferably 1% by mass or more, and more preferably 3% by mass or more. , it is more preferable that it is 5% by mass or more. Moreover, the content is preferably 55 mass% or less, more preferably 50 mass% or less, and even more preferably 45 mass% or less.

[0041] In a copolymer containing structural units derived from a monomer having a nitrile group, the total content of structural units derived from monomer A is preferably 35% by mass or more, and more preferably 40% by mass or more, It is more preferable that it is 50% by mass or more. Moreover, the total content is preferably 94 mass% or less, more preferably 92 mass% or less, and even more preferably 90 mass% or less.

[0042] In a copolymer containing structural units derived from a monomer having a nitrile group, the total content of structural units derived from monomer B1 is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, It is more preferable that it is 1.0 mass% or more. Moreover, the total content is preferably 30 mass% or less, more preferably 25 mass% or less, and even more preferably 20 mass% or less.

[0043] In the copolymer that does not contain structural units derived from monomers having a nitrile group, the total content of structural units derived from monomer A is preferably 70% by mass or more, and more preferably 75% by mass or more. , it is more preferable that it is 80% by mass or more. Moreover, the total content is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 97% by mass or less.

[0044] In the copolymer that does not contain structural units derived from monomers having a nitrile group, the total content of structural units derived from monomer B1 is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. , it is more preferable that it is 1.0% by mass or more. Moreover, the total content is preferably 30 mass% or less, more preferably 25 mass% or less, and even more preferably 20 mass% or less.

[0045] In at least two types of polymers, the difference in the proportion of structural units derived from (meth)acrylonitrile monomer is preferably 1% by mass or more, more preferably 3% by mass or more, and 5% by mass. It is more desirable to have more than this. The upper limit of the difference in the proportion occupied by the structural unit derived from the (meth)acrylonitrile monomer is not particularly limited, but is preferably 55% by mass or less, more preferably 50% by mass or less, and even more preferably 45% by mass or less. .

[0046] Preferred combinations of two types of (meth)acrylic polymers include (I) and (II) below, with (I) being preferred.

(I) Combination of (meth)acrylic polymer containing nitrile group and (meth)acrylic polymer not containing nitrile group

(II) Both types are (meth)acrylic polymers containing nitrile groups, and the content of structural units derived from (meth)acrylonitrile monomer is different.

[0047] 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. Also, for example, it may be 1.0×10 ⁶ or less, or 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. Also, for example, it may be 5.0×10 ⁶ or less, and may be 1.0×10 ⁶ or less.

Mn and Mw of the polymer are measured by a conventional method using GPC (gel permeation chromatography).

[0048] The content of the polymer with the highest content in the release layer is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, relative to the total polymer content. If the content of the polymer with the highest content is 95% by mass or less, irregularities tend to be easily formed on the surface of the release film.

[0049] When the polymer is a cross-linked polymer, it is preferable to use a cross-linking agent. Examples of the crosslinking agent include known crosslinking agents such as isocyanate compounds, melamine compounds, and epoxy compounds. Furthermore, from the viewpoint of forming a loosely spread network-like structure, it is more preferable that the crosslinking agent is a polyfunctional crosslinking agent such as tri- or tetra-functional.

[0050] The isocyanate crosslinking agent is not particularly limited and can be selected from compounds having a known isocyanate group (isocyanate compound). From the viewpoint of reactivity, difunctional isocyanate compounds (compounds having two isocyanate groups) and polyfunctional isocyanate compounds (compounds having three or more isocyanate groups) are preferable, and polyfunctional isocyanate compounds are more preferable.

[0051] Examples of the difunctional isocyanate compound include aliphatic diisocyanate compounds, alicyclic diisocyanate compounds, aromatic diisocyanate compounds, carbodiimide modified products of these diisocyanate compounds, and polymer compounds having these diisocyanate compounds in their molecules. there is.

[0052] As aliphatic diisocyanate compounds, 1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, and methyl norbornane diisocyanate (NBDI). etc. can be mentioned.

[0053] Examples of alicyclic diisocyanate compounds include trans-cyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12-MDI (hydrogenated MDI), etc. there is.

[0054] As aromatic diisocyanate compounds, dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenyl Methane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethyl methylcellulose Examples include silylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), and 1,5-naphthalene diisocyanate (NDI).

[0055] Examples of the polyfunctional isocyanate compound include a trimer of a difunctional isocyanate compound and a polymer compound having a trimer of a difunctional isocyanate compound in the molecule.

Examples of the trimer of the difunctional isocyanate compound include the isocyanurate form of the difunctional isocyanate compound, the adduct form (adduct) of the difunctional isocyanate compound, and the biuret form of the difunctional isocyanate compound.

[0056] The content of the crosslinking agent contained in the release layer may be, for example, 0.1 parts by mass to 50 parts by mass, or 1 part by mass to 40 parts by mass, based on 100 parts by mass of the solid content of the polymer contained in the release layer.

[0057] The release layer may contain an anchoring enhancer, a crosslinking accelerator, a colorant, an antistatic agent, etc., if necessary. For example, when the release layer contains an antistatic agent, discharge is less likely to occur during peeling, and electrostatic destruction of electronic components is suppressed.

[0058] When Raman spectroscopic measurement is performed on the unevenness of the surface of the release layer, it is preferable that at least a portion of the convex portion and at least a portion of the concave portion exhibit different peak intensities. As an example, the polymer component ratio may be different in at least part of the convex part and at least part of the concave part. As a more specific example, it is preferable that the content of the nitrile group-containing (meth)acrylic polymer is different in at least part of the convex part and at least part of the concave part. Additionally, it is preferable that the peaks showing different peak intensities are peaks originating from nitrile groups.

[0059] Raman spectroscopic measurement of each concavo-convex portion uses a Raman spectroscopic device. As a Raman spectroscopy device, for example, “DXR2xi” manufactured by Thermo Fischer Scientific Inc. is used, and measurement is performed under the following conditions.

·Wavelength: 532㎚

·Output: 10㎽

·Exposure time: 0.05 seconds

·Number of scans: 1000 times

·Aperture: 25㎛ pinhole

·Objective lens: 100x

[0060] The component ratio in each uneven portion is measured by obtaining a spectrum by Raman spectroscopy at each point for each portion irradiated with a laser. For example, the peak of the Raman spectrum for a specific component (such as a nitrile group) constituting the release layer is identified in advance, and based on the signal intensity, the relative difference between the specific component in one part and the other part is determined. Check the content.

[0061] In the release layer, at least one region preferably contains a (meth)acrylic polymer containing a nitrile group, and the other region may or may not contain a (meth)acrylic polymer containing a nitrile group. You don't have to. From the viewpoint of making it easier to create irregularities on the surface of the release layer, it is preferable that the other area does not contain a (meth)acrylic polymer containing a nitrile group. In addition, whether a region contains a (meth)acrylic polymer containing a nitrile group can be confirmed by not detecting a spectral peak corresponding to a nitrile group when the region is subjected to component analysis using micro-Raman spectroscopy, which will be described later. You can.

[0062] In each region, when the surface of the release layer is observed planarly, the inside of the layer may exhibit a phase separation state, and a continuous phase and a discontinuous phase may be formed. The area ratio of the continuous phase and the discontinuous phase can be adjusted by the mixing ratio of the polymer contained in the release layer. The polymer with a small content in the release layer is contained in the discontinuous phase, and the polymer with a large content in the release layer is contained in the continuous phase.

[0063] Additionally, it is preferable that the surface of the release layer has a concavo-convex shape, and that the polymer component ratio in at least part of the convex portion is different from the polymer component ratio in at least part of the concave portion. As an example, the mass-based content of nitrile group-containing (meth)acrylic polymer is different in at least part of the convex portion and at least part of the concave portion, and at least part of the convex portion is more nitrile group-containing (meth)acrylic polymer than at least part of the concave portion. It is preferable that the content in terms of polymer mass is high.

[0064] Figure 2 is a photograph and analysis graph of the surface of the release layer using a laser microscope. Observation is performed with a 50x objective lens using a “VK-X3000” manufactured by KEYENCE CORPORATION as a laser microscope. Although the above-described laser microscope is used in Figure 2, another laser microscope may be used for the surface of the release layer.

[0065] In Figure 2, sample G1 is a conventional release layer containing a filler, and samples G2 and G3 are a (meth)acrylic polymer (polymer A) containing a nitrile group and a (meth)acrylic polymer (polymer A) without a nitrile group. This is a release layer according to the present disclosure using B) in combination. Sample G2 has a polymer A content of 15 mass% and a polymer B content of 85 mass% in all polymers. Sample G3 contains 85 mass% of polymer A and 15 mass% of polymer B in all polymers.

[0066] The first and second rows of Figure 2 are planar photos when the surface of the release layer is observed flat, and the third row is a cross-sectional curve that interprets the uneven shape of the surface along the straight line indicated by the arrow in the second row photo. am. As shown in Fig. 2, in samples G2 and G3, the release layer is formed in a plurality of regions.

[0067] Sample G2 contains less than half of the nitrile group-containing (meth)acrylic polymer in the entire polymer, and in this case, the area of the convex portion over the entire surface is less than half. On the other hand, in sample G3, the content of nitrile group-containing (meth)acrylic polymer exceeds half of the total polymer, and in this case, the area of the convex portion occupying the entire surface exceeds half. From this, it can be seen that the convex portion has a higher content of nitrile group-containing (meth)acrylic polymer than the concave portion.

Additionally, as shown in FIG. 2, in the conventional sample G1, it can be seen that the uniformity of the shape, size, etc. of the convex portions is low because the filler is aggregated.

[0068] In sample G2, most of the concave area occupies the entire surface. On the other hand, in sample G3, the area of the concave portion occupying the entire surface is 50 area% or less. Accordingly, Sample G3 is a release film of the present disclosure.

[0069] As shown by the cross-sectional curve in FIG. 2, sample G3, which is a release film of the present disclosure, has a sharp bottom of the concave portion compared to sample G1 to which a conventional filler was added. Accordingly, it can be seen that the glossiness of the package surface molded using the release film of the present disclosure is effectively reduced.

[0070] In the release film of the present disclosure, the ratio of concave portions to the surface when the surface of the release layer is observed flat is preferably 50 area% or less, more preferably 45 area% or less, and 40 area% or less. It is more desirable. The ratio occupied by the recesses on the surface of the release layer is measured by the following method.

[0071] The surface of the release film was photographed at 400x magnification using an optical microscope. The range of the concave portion and the convex portion is distinguished from the difference in brightness and contrast of the captured image. Compare the areas of each identified concave and convex part. Concave portions and convex portions can be determined based on a three-dimensional image synthesized from a plurality of images taken at the same position in the plane direction while moving in the height direction. For this measurement, an apparatus such as a digital microscope (e.g., VHX-7000 manufactured by KEYENCE CORPORATION) can be used, and the ratio occupied by the concave portion can be calculated through image processing. If an image processing device cannot be used, the concave portion and the convex portion may be individually judged and classified for the image captured above, and the area may be calculated. When calculating the area, the separated images may be cut out and compared by weight.

[0072] When the surface of the release layer is observed flat, it is preferable that the maximum diameter of the concave portion is 30㎛ or less. If the release layer exhibits release properties, the lower limit of the maximum diameter of the concave portion is not particularly limited.

[0073] The maximum diameter of the concave portion is a value obtained by measuring the diameter of the concave portion with the largest diameter when observed with an optical microscope in one field of view at 400 times magnification.

[0074] When the surface of the release layer is observed flat with an optical microscope, the circularity of the concave portion is preferably 0.7 or more, and more preferably 0.8 or more. “Circularity” is a value obtained by the following formula, and is an index showing the complexity of the particle shape. The closer the circularity is to 1, the closer the particle shape is to the perfect circle.

Circularity = 4π × (area) ÷ (peripheral length) ²

[0075] The circularity of the concave portion is measured for 10 concave portions when observed with an optical microscope, and is taken as the arithmetic average value. The circularity of the concave portion can be calculated using known image analysis means, if necessary.

[0076] As shown in sample G1 in FIG. 2, in the case of a conventional release film to which fillers are added, the fillers tend to agglomerate and the circularity of the concave portion tends to decrease. In particular, if a large amount of filler is added to lower the proportion of the concave portions on the surface of the release layer, the fillers become more likely to aggregate with each other, and the circularity of the concave portions tends to further decrease.

[0077] Furthermore, from the relationship between the polymer mixing ratio and the proportion occupied by the convex portion in samples G2 and G3, it is assumed that the convex portion has a higher content of nitrile group-containing (meth)acrylic polymer than the concave portion. Additionally, as shown in FIG. 2, in the conventional sample G1, it can be seen that the uniformity of the shape, size, etc. of the convex portions is low because the filler is aggregated.

[0078] FIG. 3 is a spectrum result of component analysis by micro-Raman spectroscopy for the discontinuous phase (island phase, convex portion) and continuous phase (resolution, concave portion) in sample G2 of FIG. 2. Here, the discontinuous phase refers to an area that occupies a small area on the observation surface, and the continuous phase refers to an area that occupies a large area in the observation surface.

[0079] As shown in Figure 3, while the peak derived from the nitrile group is detected in the discontinuous phase (convex portion), the peak derived from the nitrile group is not detected in the continuous phase (concave portion). From these results, it can be seen that the polymer component ratios are different in the discontinuous phase (convex portion) and the continuous phase (concave portion). In addition, it can be seen that the convex portion has a higher content of nitrile group-containing (meth)acrylic polymer than the concave portion.

[0080] FIG. 4 is a spectrum result of component analysis by micro-Raman spectroscopy for the convex portions (resolution, continuous phase) and concave portions (island phase, discontinuous phase) of sample G3 in FIG. 2. While the peak derived from the nitrile group is detected in the convex part, the peak derived from the nitrile group is not detected in the concave part. From these results, it can be seen that the polymer component ratios are different in the convex portion and the concave portion. In addition, it can be seen that the convex portion has a higher content of nitrile group-containing (meth)acrylic polymer than the concave portion.

In Fig. 4, among all polymers, nitrile group-containing (meth)acrylic polymer is contained as a main component and forms a continuous phase, but this continuous phase forms convex portions. In Figure 3, the continuous phase forms a concave portion, whereas in Figure 4, it is reversed. However, in both cases of Figures 3 and 4, the convex portion has a higher content of nitrile group-containing (meth)acrylic polymer than the concave portion.

[0081] The thickness of the release layer is not particularly limited, and is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. If the thickness of the release layer is 1 μm or more, sufficient adhesion to the electronic component is obtained and penetration of the seal material is effectively suppressed.

The thickness of the release layer may be 50 μm or less and may be 25 μm or less. If the thickness of the release layer is 50 μm or less, heat shrinkage stress is unlikely to occur during heat curing of the release layer, and the flatness of the release film is likely to be maintained. Additionally, when the release film has a conductive layer, the surface resistivity of the release layer is not too far from the conductive layer, so the surface resistivity is maintained low, and electrostatic destruction of the electronic component is effectively suppressed.

Considering the ease of forming the release layer (applicability, etc.) and ensuring adhesive strength, the thickness of the release layer is preferably 1 μm to 50 μm, and more preferably 3 μm to 25 μm.

[0082] From the viewpoint of maximizing the effect of the embodiment of the present disclosure, the release layer preferably does not contain a filler, but may contain a filler. When using a filler, at least one of an organic filler and an inorganic filler may be used. The filler content may be, for example, 1 volume% or less, 0.5 volume% or less, and 0.1 volume% or less in the release layer.

The filler content (volume %) in the release layer can be calculated based on the density measured according to the Archimedes method and the specific gravity of the resin component and filler.

[0083] (Elongation at break of release layer)

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

[0084] The elongation at break (%) of the release layer of the release film is measured as follows. First, a test piece of the shape shown in FIG. 5 is produced using a release film. A tensile test is performed by holding both ends of this test piece with a testing machine. The measurement is conducted under conditions of 170°C, and the tensile speed is 200 mm/min. From the distance A between the gauges of the sample before the test (the length of the portion where the width of the test piece shown in Figure 5 is 10 mm: 40 mm) and the distance B between the gauges when the release layer is fractured, the release layer is obtained by the following formula: Calculate the elongation at break.

[0085]

[0086] To measure the elongation at break of the release layer of the release film, for example, "TENSILON tensile tester RTA-100 type" manufactured by ORIENTEC CO., LTD., and "TENSILON universal tester RTG-1210" manufactured by A&D Company, Limited. 」 or a similar testing machine with a gripping tool is used.

[0087] (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 layer) is preferably 0.15 μm or more, more preferably 0.20 μm or more, and 0.25 μm or more. It is more desirable. The upper limit of the arithmetic mean roughness (Ra) is not particularly limited, and may be, for example, 4.00 μm or less, 3.00 μm or less, or 2.00 μm or less.

[0088] The arithmetic mean roughness (Ra) of the outer surface of the release layer was measured using a surface roughness measuring device (e.g., Kosaka Laboratory Ltd., model number SE-3500), with a stylus tip diameter of 2 μm and a transfer speed. The results measured under the conditions of 0.5 mm/s and a scanning distance of 8 mm can be obtained by analyzing according to JIS B0601 (2001) or ISO 4287 (1997).

[0089] When the uneven shape of the release layer of the release film is transferred to the molded product, the release film is a percentage of the arithmetic average roughness (Ra) of the surface of the molded product relative to the arithmetic average roughness (Ra) of the surface of the release layer (transfer It is preferable that the ratio is 100% or more, more preferably 103% or more, and even more preferably 110% or more. The transfer rate of the release film is preferably 300% or less, more preferably 250% or less, and even more preferably 200% or less.

[0090] The 10-point average roughness (Rz) of the outer surface of the release layer is preferably 1.00 μm or more, more preferably 1.50 μm or more, and even more preferably 2.00 μm or more. The upper limit of the 10-point average roughness (Rz) is not particularly limited, and may be, for example, 30.00 μm or less, 20.00 μm or less, or 10.00 μm or less.

[0091] The 10-point average roughness (Rz) of the outer surface of the release layer was measured using a surface roughness measuring device (e.g., Kosaka Laboratory Ltd., model number SE-3500), with a stylus tip diameter of 2 μm and a transfer speed of 0.5 mm/mm. The results measured under the conditions of s and scanning distance of 8 mm can be obtained by analyzing according to JIS B0601 (1994).

[0092] The average spacing (Sm) of the irregularities on the outer surface of the release layer is preferably 0.30 mm or less, more preferably 0.25 mm or less, and even more preferably 0.20 mm or less. The lower limit of the average spacing (Sm) of the unevenness is not particularly limited, and may be, for example, 0.01 mm or more, 0.02 mm or more, or 0.03 mm or more.

[0093] The average spacing (Sm) of the unevenness of the outer surface of the release layer was measured using a surface roughness measuring device (e.g., Kosaka Laboratory Ltd., model number SE-3500), with a stylus tip diameter of 2 ㎛ and a transfer speed of 0.5 mm/ The results measured under the conditions of s and scanning distance of 8 mm can be obtained by analyzing according to JIS B0601 (1994).

[0094] The average length (RSm) of the roughness curve elements of the outer surface of the release layer is preferably 0.50 mm or less, more preferably 0.30 mm or less, and even more preferably 0.10 mm or less. The lower limit of RSm is not particularly limited, and may be, for example, 0.01 mm or more, 0.03 mm or more, or 0.05 mm or more.

[0095] The average length (RSm) of the roughness curve elements of the outer surface of the release layer was measured using a surface roughness measuring device (e.g., Kosaka Laboratory Ltd., model number SE-3500), with a stylus tip diameter of 2 ㎛ and a transfer speed of 0.5. The results measured under the conditions of mm/s and scanning distance of 8 mm can be obtained by analyzing according to JIS B0601 (2001).

[0096] The maximum height (Ry) of the outer surface of the release layer is preferably 1.0 μm or more, more preferably 1.5 μm or more, and even more preferably 2.0 μm or more. The upper limit of the maximum height (Ry) is not particularly limited, and may be, for example, 30.0 μm or less, 20.0 μm or less, or 10.0 μm or less.

[0097] The maximum height (Ry) of the outer surface of the release layer was measured using a surface roughness measuring device (e.g., Kosaka Laboratory Ltd., model number SE-3500), with a stylus tip diameter of 2 ㎛, a transfer speed of 0.5 mm/s, and The results measured under the conditions of a scanning distance of 8 mm can be obtained by analyzing according to JIS B0601 (2001).

[0098] In the release film, when the uneven shape of the release layer of the release film is transferred to the molded product, the difference between the 10-point average roughness (Rz) and the maximum height (Ry) of the surface of the molded product is preferably 2.00㎛ or less, and 1.50㎛ It is more preferable that it is ㎛ or less, and it is still more preferable that it is 1.00 ㎛ or less. The difference is preferably 0.30 μm or more, more preferably 0.40 μm or more, and even more preferably 0.50 μm or more.

[0099] The arithmetic average roughness (Ra), 10-point average roughness (Rz), average spacing of irregularities (Sm), average length of roughness curve elements (RSm), and maximum height (Ry) of the outer surface of the release layer are, It can be adjusted by the mixing ratio of the polymer contained in the release layer, the thickness of the release layer, the amount of the crosslinking agent when using a crosslinking agent, and the amount of catalyst when using a catalyst.

[0100] The glossiness (20°) of the surface of the release layer is preferably 28.0 or less, more preferably 25.0 or less, and even more preferably 20.0 or less. The lower limit of the glossiness (20°) of the surface of the release layer is not particularly limited, and may be, for example, 1.0 or more, 3.0 or more, or 5.0 or more.

[0101] The glossiness (60°) of the surface of the release layer is preferably 44.0 or less, more preferably 40.0 or less, and even more preferably 35.0 or less. The lower limit of the glossiness (60°) of the surface of the release layer is not particularly limited, and may be, for example, 3.0 or more, 5.0 or more, or 10.0 or more.

[0102] The glossiness (85°) of the surface of the release layer is preferably 60.0 or less, more preferably 45.0 or less, and even more preferably 35.0 or less. The lower limit of the glossiness (85°) of the surface of the release layer is not particularly limited, and may be, for example, 1.0 or more, 3.0 or more, or 5.0 or more.

[0103] Glossiness is measured based on the specular gloss measurement method of JIS Z 8741 (1997) using a gloss meter. Glossiness (20°) is measured at an incident angle of 20°, glossiness (60°) is measured at an incident angle of 60°, and glossiness (85°) is measured at an incident angle of 85°.

[0104] When the release film transfers the uneven shape of the release layer of the release film to the molded product, the glossiness (20°) of the surface of the molded product is preferably 8.0 or less, more preferably 5.0 or less, and even more preferably 3.0 or less. desirable. The lower limit of the glossiness (20°) of the molded product is not particularly limited, and may be, for example, 0.3 or more, 0.5 or more, or 1.0 or more.

[0105] When the release film transfers the uneven shape of the release layer of the release film to the molded product, the glossiness (60°) of the surface of the molded product is preferably 30.0 or less, more preferably 20.0 or less, and 15.0 or less. It is more desirable. The lower limit of the glossiness (60°) of the surface of the molded product is not particularly limited, and may be, for example, 1.0 or more, 3.0 or more, or 5.0 or more.

[0106] When the release film transfers the uneven shape of the release layer of the release film to the molded product, the glossiness (85°) of the surface of the molded product is preferably 65.0 or less, more preferably 50.0 or less, and 30.0 or less. It is more desirable. The lower limit of the glossiness (85°) of the surface of the molded product is not particularly limited, and may be, for example, 1.0 or more, 5.0 or more, or 10.0 or more.

[0107] [Base layer]

The base layer is not particularly limited and can be appropriately selected from base layers used in the relevant technical field. From the viewpoint of improving followability to the shape of the mold, it is preferable to use a resin-containing base layer with excellent stretchability.

Considering the heating temperature (about 100°C to 200°C) for forming the seal material, the base material layer preferably has heat resistance equal to or higher than this heating temperature. Additionally, from the viewpoint of suppressing the occurrence of wrinkles, tears, etc. when the release film is mounted on the mold and when the seal material flows, it is desirable to select the material of the base layer in consideration of the elastic modulus and elongation during heating.

[0108] The material of the base layer is preferably polyester resin from the viewpoint of heat resistance and elastic modulus when heated. Examples of polyester resins include polyethylene terephthalate resin, polyethylene naphthalate resin, and polybutylene terephthalate resin, as well as copolymers and modified resins thereof.

[0109] The base layer is preferably in a sheet shape, more preferably a polyester resin molded into a sheet shape, and even more preferably a polyester film. From the viewpoint of mold followability, biaxially stretched polyester It is preferable that it is a film.

[0110] The thickness of the base layer is not particularly limited, and is preferably 5 μm to 200 μm, and more preferably 10 μm to 100 μm. If the thickness is 5 μm or more, handling is excellent and wrinkles tend to be difficult to form. If the thickness is 100 μm or less, the followability to the mold during molding is excellent, so the occurrence of wrinkles, etc. in the molded semiconductor package tends to be suppressed.

[0111] [Other composition]

Depending on the material of the base layer, it is desirable to design the release sheet so that it is easy to peel from the mold. For example, surface processing such as satin finish processing is performed on the surface opposite to the base layer in contact with the release layer, that is, the mold side surface of the base layer, or another release layer (second release layer) is formed. You can do it. 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 above-mentioned release layer (hereinafter also referred to as “specific release layer”) may be used. The thickness of the second release layer is not particularly limited, but is preferably 0.1 μm to 100 μm.

[0112] Additionally, if necessary, an anchoring improvement layer, an antistatic layer, a colored layer, etc. may be formed between a specific release layer and the base material layer, between the base material layer and the second release layer, etc.

[0113] <Method for manufacturing release film>

The release film of this disclosure can be manufactured by a known method. For example, the release film of the present disclosure can be manufactured by applying the composition for forming a release layer to the base layer and drying it. The composition for forming a release layer contains at least two types of polymers described above, and may further contain other resin components and other components added as desired.

[0114] [Preparation of composition for forming release layer]

The method for preparing the composition for forming a release layer is not particularly limited, and known composition preparation methods can be used. The solvent used in preparing the composition for forming a release layer is not particularly limited, and it is preferable that it is an organic solvent capable of dissolving the polymer. Examples of organic solvents include toluene, methyl ethyl ketone, and ethyl acetate.

[0115] [Grant and Dry]

The method of applying the composition for forming a release layer to the base layer is not particularly limited, and known application methods such as roll coating, bar coating, and kiss 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 of drying the provided composition for forming a release layer is not particularly limited, and a known drying method can be used. For example, drying at 50°C to 150°C for 0.1 to 60 minutes may be used.

[0116] <Use of release film>

The release film of the present disclosure is used, for example, when sealing a semiconductor chip with a sealant. The release film of the present disclosure is preferably used for transfer molding or compression molding.

[0117] By using the release film of the present disclosure, it is possible to easily take out the semiconductor package (molded product) from the mold while suppressing damage to the semiconductor package. In addition, by using the release film of the present disclosure, the glossiness of the seal material on the surface of the semiconductor package (molded product) is effectively reduced, flow marks are suppressed, and the uniformity of the appearance is excellent.

[0118] <Manufacturing method of semiconductor package>

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

[0119] In the method of manufacturing a semiconductor package, first, the release film of the present disclosure described above is placed in a mold of a molding device, and the release film is made to follow the shape of the mold. A method of making the release film follow the shape of the mold includes vacuum adsorption.

[0120] Then, the semiconductor chip is sealed with a sealant within the mold following the release film. A semiconductor package can be manufactured by placing a semiconductor chip and a release film in a mold and sealing the semiconductor chip with a sealant. After manufacturing the semiconductor package, the mold is opened and the molded semiconductor package is taken out.

[0121] In the method for manufacturing a semiconductor package of the present disclosure, since the release film of the present disclosure is used, the glossiness of the seal material on the surface of the semiconductor package is effectively reduced, flow marks are suppressed, and appearance uniformity is excellent. You can obtain a semiconductor package.

[0122] Examples of semiconductor chips used in the above method include semiconductor elements, condensers, terminals, etc. The type of sealing material used in the above method is not particularly limited, and examples include resin compositions containing epoxy resin, acrylic resin, etc.

[0123] On the surface of the semiconductor package, the uneven shape of the surface of the release film is transferred, and the transfer rate is preferably 100% or more, more preferably 103% or more, and even more preferably 110% or more. The transfer rate of the release film is preferably 300% or less, more preferably 250% or less, and even more preferably 200% or less.

The transfer rate mentioned here has the same meaning as the transfer rate explained in the release film mentioned above.

[0124] The arithmetic average roughness (Ra) of the surface of the semiconductor package is preferably 0.15 μm or more, more preferably 0.20 μm or more, and even more preferably 0.25 μm or more. The upper limit of the arithmetic mean roughness (Ra) of the surface of the semiconductor package is not particularly limited, and may be, for example, 4.00 μm or less, 3.00 μm or less, or 2.00 μm or less.

The arithmetic average roughness (Ra) of the surface of the semiconductor package is measured in the same manner as the arithmetic average roughness (Ra) of the surface of the release layer.

[0125] The 10-point average roughness (Rz) of the surface of the semiconductor package is preferably 1.00 μm or more, more preferably 2.00 μm or more, and even more preferably 3.80 μm or more. The upper limit of the 10-point average roughness (Rz) of the surface of the semiconductor package is not particularly limited, and may be, for example, 30.00 μm or less, 20.00 μm or less, or 10.00 μm or less.

The 10-point average roughness (Rz) of the surface of the semiconductor package is measured in the same manner as the 10-point average roughness (Rz) of the surface of the release layer.

[0126] The average spacing (Sm) of the irregularities on the surface of the semiconductor package is preferably 0.30 mm or less, more preferably 0.25 mm or less, and even more preferably 0.20 mm or less. The lower limit of the average spacing (Sm) of the irregularities on the surface of the semiconductor package is not particularly limited, and may be, for example, 0.01 mm or more, 0.02 mm or more, or 0.03 mm or more.

The average spacing (Sm) of the irregularities on the surface of the semiconductor package is measured in the same manner as the average spacing (Sm) of the irregularities on the surface of the release layer.

[0127] The average length (RSm) of the roughness curve elements of the surface of the semiconductor package is preferably 0.12 mm or less, more preferably 0.10 mm or less, and even more preferably 0.08 mm or less. The lower limit of the average length (RSm) of the surface roughness curve elements of the semiconductor package is not particularly limited, and may be, for example, 0.01 mm or more, 0.03 mm or more, or 0.05 mm or more.

The average length (RSm) of the roughness curve elements on the surface of the semiconductor package is measured in the same manner as the average length (RSm) of the roughness curve elements on the surface of the release layer.

[0128] The maximum height (Ry) of the surface of the semiconductor package is preferably 1.0 μm or more, more preferably 2.0 μm or more, and even more preferably 5.2 μm or more. The upper limit of the maximum height (Ry) of the surface of the semiconductor package is not particularly limited, and may be, for example, 30.0 μm or less, 20.0 μm or less, or 10.0 μm or less.

The maximum height (Ry) of the surface of the semiconductor package is measured in the same manner as the maximum height (Ry) of the surface of the release layer.

[0129] The difference between the 10-point average roughness (Rz) and the maximum height (Ry) of the surface of the semiconductor package (molded product) is preferably 3.00 μm or less, more preferably 2.50 μm or less, and even more preferably 2.00 μm or less. The difference is preferably 0.50 μm or more, more preferably 1.00 μm or more, and even more preferably 1.50 μm or more.

[0130] The glossiness (20°) of the surface of the semiconductor package is preferably 8.0 or less, more preferably 5.0 or less, and even more preferably 3.0 or less. The lower limit of the glossiness (20°) of the surface of the semiconductor package is not particularly limited, and may be, for example, 0.3 or more, 0.5 or more, or 1.0 or more.

[0131] The glossiness (60°) of the surface of the semiconductor package is preferably 30.0 or less, more preferably 20.0 or less, and even more preferably 15.0 or less. The lower limit of the glossiness (60°) of the surface of the semiconductor package is not particularly limited, and may be, for example, 1.0 or more, 3.0 or more, or 5.0 or more.

[0132] The glossiness (85°) of the surface of the semiconductor package is preferably 65.0 or less, more preferably 50.0 or less, and even more preferably 30.0 or less. The lower limit of the glossiness (85°) of the surface of the semiconductor package is not particularly limited, and may be, for example, 1.0 or more, 5.0 or more, or 10.0 or more.

[0133] The glossiness of the surface of the semiconductor package is measured in the same manner as the glossiness of the surface of the release layer.

[Example]

[0134] Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to these examples.

[0135] (Synthesis of Resin A and Resin B)

The monomers shown in Table 1 below were used in the amounts (mass parts) shown in Table 1, and copolymerized by solution polymerization to obtain Resin A and Resin B.

For the obtained Resin A and Resin B, the number average molecular weight Mn and the weight average molecular weight Mw were measured by standard polystyrene conversion by gel permeation chromatography (GPC).

The SP values for the obtained Resin A and Resin B are shown in Table 1.

[0136] [Table 1]

[0137] The monomers in Table 1 are shown below.

BA: Butyl acrylate

4-HBA: 4-hydroxybutyl acrylate

2-HEMA: 2-hydroxyethyl methacrylate

·AN: Acrylic acid nitrile

[0138] <Example 1>

For a total of 100 parts by mass of Resin A (30 parts by mass) and Resin B (70 parts by mass), 20 parts by mass of a di- and tri-functional polyisocyanate mixture as a crosslinking agent was added to toluene to form a toluene solution with a solid content of 15% by mass. Thus, a composition for forming a release layer was prepared.

As a base layer, a biaxially stretched polyethylene terephthalate film (UNITIKA LTD.: S-38) with a thickness of 38 μm was used and subjected to corona treatment. Thereafter, the composition for forming a release layer was applied and dried on one side of the base material layer using a roll coater so that the average thickness after drying was 5 μm to form a release layer, thereby obtaining a release film.

[0139] <Examples 2 to 7>

A release film was obtained in the same manner as in Example 1, except that the type and addition amount of the resin and crosslinking agent were changed as shown in Table 2. The numerical values of the resin, crosslinking agent, and filler in Table 2 represent the blending amount (parts by mass).

[0140] <Comparative Example 1>

A release film was prepared in the same manner as in Example 1, except that 20 parts by mass of the crosslinking agent was used for Resin A (100 parts by mass), and 10 parts by mass of polymethyl methacrylate particles (average particle diameter 3 μm) were used as filler. was produced.

[0141] <Comparative Examples 2, 3>

A release film was produced in the same manner as Comparative Example 1, except that the amount of filler was changed as shown in Table 2.

[0142] <Evaluation test>

(Measurement of surface condition of release layer)

By the above-described method, the ratio (area %) of concave portions on the surface of the release layer of the release film was determined by image processing using a digital microscope VHX-7000 manufactured by KEYENCE CORPORATION.

In addition, the arithmetic average roughness (Ra), the 10-point average roughness (Rz), the average spacing of irregularities (Sm), the average length of roughness curve elements (RSm), and the maximum height ( Ry) was measured. For the measurement, “Surface Roughness Meter SE-3500” manufactured by Kosaka Laboratory Ltd. was used. The results are shown in Table 2.

[0143] (Glossiness of release layer)

By the method described above, the glossiness (20°, 60°, and 85°) of the surface of the release layer of the release film was measured. The results are shown in Table 2.

[0144] (Surface roughness of molded product)

The release film is placed so that the sealant (Showa Denko Materials co., Ltd.: product name “CEL-9750 ZHF10”) touches the release layer side of the release film, and cured by heating and pressing using a hydraulic press at a temperature of 180°C. A molded product of the sealant was produced in 5 minutes. Thereafter, the release film is peeled from the molded product of the seal material, and the surface of the molded product of the obtained seal material is evaluated for arithmetic average roughness (Ra), 10-point average roughness (Rz), and unevenness by the same method as the surface roughness of the release layer. The average spacing (Sm), average length of roughness curve elements (RSm), and maximum height (Ry) were measured. The results are shown in Table 2.

[0145] (Glossiness of molded product)

By the method described above, the glossiness (20°, 60°, and 85°) of the surface of the molded article was measured. The results are shown in Table 2.

[0146] (transfer rate)

The transfer rate was determined using the arithmetic average roughness (Ra) of the surface of the release film obtained by the above-described method and the arithmetic average roughness (Ra) of the surface of the molded article. The results are shown in Table 2.

[0147] [Table 2]

[0148] As shown in the results in Table 2, the release films of Examples 1 to 7 had an effective reduction in gloss compared to the release films of Comparative Examples 1 to 3, and it was found that the effect of reducing flow marks was excellent. You can.

[0149] 10: base layer
20: release layer
30: release film

Claims (14)

Includes a release layer and a base layer,
The release layer includes two or more types of polymers, and the surface of the release layer has a concavo-convex shape,
A release film in which the ratio of concave portions to the surface of the release layer when observed flat is 50 area% or less. Includes a release layer and a base layer,
The release layer includes two or more types of polymers, and the surface of the release layer has a concavo-convex shape,
The transfer rate, which is the percentage of the arithmetic average roughness (Ra) of the surface of the molded product when the uneven shape of the molded product is transferred to the molded product relative to the arithmetic average roughness (Ra) of the surface of the molded release layer, is 100. % or more release film. Includes a release layer and a base layer,
The release layer includes two or more types of polymers, and the surface of the release layer has a concavo-convex shape,
A release film wherein the glossiness (20°) of the surface of the molded product when the uneven shape of the release layer is transferred to the molded product is 8.0 or less. According to paragraph 1,
A release film wherein at least one of the polymers is a (meth)acrylic polymer containing a nitrile group. According to paragraph 1,
A release film that exhibits different peak intensities in at least a portion of the convex portion and at least a portion of the concave portion when Raman spectroscopic measurement is performed on the unevenness of the surface of the release layer. According to paragraph 1,
A release film in which the component ratio of the polymer in the convex portions of the surface of the release layer is different from the component ratio of the polymer in the concave portions. According to clause 6,
A release film in which the mass-based content of the nitrile group-containing (meth)acrylic polymer in the convex portion is greater than the mass-based content of the nitrile group-containing (meth)acrylic polymer in the concave portion. According to paragraph 1,
A release film in which the difference in SP values of at least two of the above polymers is 0.3 or more. According to paragraph 1,
At least one type of the polymer is a polymer containing a structural unit derived from a (meth)acrylonitrile monomer,
A release film in which at least two of the above polymers have a difference in proportions of structural units derived from (meth)acrylonitrile monomer of 1% by mass or more. According to paragraph 1,
A release film in which the content of the polymer with the highest content in the release layer is 95% by mass or less with respect to the total content of the polymer. According to paragraph 1,
A release film wherein the base material layer is a polyester film. According to paragraph 1,
A release film wherein the release layer has a thickness of 1 μm to 50 μm. According to paragraph 1,
The release film is used for transfer molding or compression molding. A method of manufacturing a semiconductor package, comprising performing a transfer molding process or a compression molding process using the release film according to any one of claims 1 to 13.