Temporary protective film for semiconductor sealing molding, method for manufacturing the same, lead frame with temporary protective film, temporarily-protected sealing molded body, and method for manufacturing semiconductor package

Abstract

A temporary protective film for semiconductor encapsulation includes a support film and an adhesive layer disposed on one or both sides of the support film. During the encapsulation process of forming an encapsulation layer for encapsulating a semiconductor device mounted on a chip pad of a leadframe, the adhesive layer temporarily protects the side of the leadframe opposite to the semiconductor device. The adhesive layer comprises a thermoplastic resin and a low-molecular-weight compound with a molecular weight less than 1000. The total chlorine content in the low-molecular-weight compound is 12.5% ​​by mass or more.

Description

Technical Field

[0001] This invention relates to a temporary protective film for semiconductor encapsulation and molding, a method for manufacturing the same, a lead frame with a temporary protective film, a temporarily protected encapsulated body, and a method for manufacturing semiconductor packages. Background Technology

[0002] In semiconductor packages, a structure is sometimes used where the sealing layer is formed only on the semiconductor element side of the leadframe, and the back side of the leadframe is exposed (Patent Documents 1 and 2). In the manufacture of semiconductor packages with this structure, to prevent the sealing resin from wrapping around to the back side of the leadframe during sealing molding, a temporary protective film is sometimes applied to temporarily protect the back side of the leadframe (Patent Documents 3 and 4). The temporary protective film is peeled off from the leadframe after the sealing layer is formed.

[0003] Previous technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 5-129473 Patent Document 2: Japanese Patent Application Publication No. 10-12773 Patent Document 3: International Publication No. 2021 / 206058 Patent Document 4: International Publication No. 2021 / 206069 Summary of the Invention

[0004] The technical problem to be solved by the invention This invention relates to a temporary protective film for semiconductor encapsulation that can be attached to a lead frame and easily peeled off after being subjected to a high-temperature thermal process of around 400°C.

[0005] means for solving technical problems This invention includes the following: [1] A temporary protective film for semiconductor encapsulation includes a support film and an adhesive layer disposed on one or both sides of the support film. During the encapsulation process of forming an encapsulation layer for encapsulating a semiconductor element mounted on a chip pad of a leadframe, the film temporarily protects the side of the leadframe opposite to the semiconductor element. The adhesive layer comprises thermoplastic resin and compounds with a molecular weight of less than 1000, i.e., low molecular weight components. The total chlorine content in the low molecular weight component is 12.5% ​​by mass or more. [2] The temporary protective film for semiconductor encapsulation according to claim 1, wherein, The content of the low molecular weight component is more than 3 parts by mass and less than 20 parts by mass relative to the content of the thermoplastic resin (100 parts by mass). [3] A temporary protective film for semiconductor encapsulation includes a support film and an adhesive layer disposed on one or both sides of the support film. During the encapsulation process of forming an encapsulation layer for encapsulating a semiconductor element mounted on a chip pad of a leadframe, the film temporarily protects the side of the leadframe opposite to the semiconductor element. The adhesive layer comprises thermoplastic resin and compounds with a molecular weight of less than 1000, i.e., low molecular weight components. The total chlorine content in the adhesive layer is 1.11% by mass or more. [4] The temporary protective film for semiconductor encapsulation according to any one of [1] to [3], wherein, The low molecular weight component comprises an epoxy compound having one or more epoxy groups. [5] A method for manufacturing a temporary protective film for semiconductor encapsulation, the temporary protective film comprising a support film and an adhesive layer disposed on one or both sides of the support film, for temporarily protecting the side of the lead frame opposite to the semiconductor element during the encapsulation process of forming an encapsulation layer for encapsulating a semiconductor element mounted on a chip pad of a leadframe. The method includes the following steps: Prepare compounds with a molecular weight of less than 1000, i.e., low molecular weight components; The low molecular weight component is mixed with a thermoplastic resin and a solvent to form a varnish; A film containing the varnish is formed on the support film; and The adhesive layer is formed by removing the solvent from the membrane; The total chlorine content in the low molecular weight component is 12.5% ​​by mass or more. [6] A lead frame with a temporary protective film, comprising: Leadframe with chip pads; and Temporary protective film for semiconductor encapsulation as described in any one of [1] to [4] The temporary protective film is attached to one surface of the lead frame with the adhesive layer of the temporary protective film in contact with the lead frame. [7] A temporary protective sealed molded body, comprising: Leadframe with chip pads; A semiconductor element is mounted on the chip pad on one side of the lead frame; Encapsulating layer for sealing the semiconductor device; and Temporary protective film for semiconductor encapsulation as described in any one of [1] to [4] The temporary protective film is attached to the side of the lead frame opposite to the semiconductor element, with the adhesive layer of the temporary protective film in contact with the lead frame. [8] A method for manufacturing a semiconductor package includes the following steps in sequence: On one side of a lead frame having chip pads, a temporary protective film for semiconductor encapsulation as described in any one of [1] to [4] is attached in the direction in which the adhesive layer contacts the lead frame; A semiconductor element is mounted on the side of the chip pad opposite to the temporary protective film; Forming a sealing layer to seal the semiconductor element, thereby obtaining a sealed molded body having temporary protection for the lead frame, the semiconductor element, and the sealing layer; and The temporary protective film is peeled off from the sealed molded body. [9] According to the method described in [8], wherein, The lead frame has a plurality of chip pads, on each of the plurality of chip pads, a semiconductor element is mounted. The method further includes the following steps: after peeling the temporary protective film from the encapsulation molded body, the encapsulation molded body is divided to obtain a semiconductor package having one of the chip pads and the semiconductor element.

[0015] Invention Effects The present invention provides a temporary protective film for semiconductor encapsulation that can be attached to a lead frame and can be easily peeled off after being subjected to a high-temperature thermal process of about 400°C. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view showing an example of a temporary protective film.

[0017] Figure 2 This is a cross-sectional view showing an example of a temporary protective film.

[0018] Figure 3 This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device.

[0019] Figure 4 This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device.

[0020] Figure 5 This is a cross-sectional view showing an example of a semiconductor device.

[0021] Figure 6This is a three-dimensional diagram representing an example of a reel body.

[0022] Figure 7 This is the front view representing an example of a package.

[0023] Figure 8 This is the front view showing an example of packaging. Detailed Implementation

[0024] This invention is not limited to the following examples. The upper and lower limits of the numerical ranges described in this specification can be combined arbitrarily. The numerical values ​​described in the embodiments can also be used as the upper or lower limits of the numerical range.

[0025] Temporary protective film Figure 1 This is a cross-sectional view showing an example of a temporary protective film. Figure 1 The temporary protective film 10 shown consists of a support film 1 and an adhesive layer 2 disposed on one side of the support film 1. Alternatively, adhesive layers may be formed on both sides of the support film 1. Figure 2 This is also a cross-sectional view showing an example of a temporary protective film. Figure 2 The temporary protective film 10' has: a support film 1, an adhesive layer 2 disposed on one main surface of the support film 1, and a non-adhesive layer 3 disposed on the other main surface of the support film 1. In the sealing process of forming a sealing layer to seal semiconductor elements mounted on die pads of a leadframe, these temporary protective films are attached to the back side of the leadframe (the side opposite to the side with the semiconductor element) and can be used as temporary protective films for semiconductor sealing during sealing.

[0026] Adhesive layer 2 contains thermoplastic resin and low molecular weight components. The thermoplastic resin is composed of polymers with a molecular weight of 1000 or higher. The low molecular weight components are composed of compounds with a molecular weight of less than 1000.

[0027] The thermoplastic resin in adhesive layer 2 may be at least one selected from the group consisting of aromatic polyetheramide imide, aromatic polyetherimide, aromatic polyetheramide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamide imide, aromatic polyether, and aromatic polyester imide. From the viewpoint of heat resistance and adhesion, the thermoplastic resin may be at least one selected from the group consisting of aromatic polyetheramide imide, aromatic polyetherimide, and aromatic polyetheramide, or may be aromatic polyetheramide imide.

[0028] Aromatic polyether amide imides can be condensation polymers formed from an acid component containing an aromatic tricarboxylic acid or a reactive derivative thereof and an amine component containing an aromatic diamine, wherein at least one of the aromatic tricarboxylic acid or aromatic diamine contains a compound having a plurality of aromatic groups and oxygen groups (-O-) bonded to each other. Aromatic polyether imides can be condensation polymers formed from an acid component containing an aromatic tetracarboxylic acid or a reactive derivative thereof and an amine component containing an aromatic diamine, wherein at least one of the aromatic tetracarboxylic acid or aromatic diamine contains a compound having a plurality of aromatic groups and oxygen groups bonded to each other. Aromatic polyether amides can be condensation polymers formed from an acid component containing an aromatic dicarboxylic acid or a reactive derivative thereof and an amine component containing an aromatic diamine, wherein at least one of the aromatic dicarboxylic acid or aromatic diamine contains a compound having a plurality of aromatic groups and oxygen groups bonded to each other. The reactive derivatives of the carboxylic acid can be, for example, acid anhydrides or acyl chlorides.

[0029] Aromatic polyether amide imides and aromatic polyamide imides may contain structural units derived from trimellitic acid or its reactive derivatives. Aromatic polyimides and aromatic polyether imides may contain structural units derived from pyromellitic acid, polynuclear aromatic tetracarboxylic acids, or their reactive derivatives. Examples of polynuclear aromatic tetracarboxylic acids include bisphenol A bis(trimethacrylate) and oxydiphthalic acid. Aromatic polyamides may contain structural units derived from terephthalic acid, isophthalic acid, or their reactive derivatives.

[0030] Aromatic polyether amide imides, aromatic polyether imides, and aromatic polyether amides may contain structural units derived from aromatic diamines having an oxygen-containing structure, such as those selected from 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'-diaminodiphenyl ether, bis[4-(4-aminophenoxy)phenyl] ether, and 2,2-bis[4-(4-aminophenoxy)]hexafluoropropane. Aromatic polyether amide imides, aromatic polyether imides, and aromatic polyether amides may further contain structural units derived from other diamines selected from aromatic diamines without an oxygen-containing structure (e.g., 4,4'-methylenebis(2-isopropylaniline)), siloxane diamines (e.g., 1,3-bis(3-aminopropyl)tetramethyldisiloxane), and α,ω-diaminoalkanes (e.g., 1,12-diaminododecane, 1,6-diaminohexane).

[0031] In aromatic polyether amide imides, aromatic polyether imides, and aromatic polyether amides, based on the total amount of structural units derived from diamine components, the proportion of structural units derived from oxygen-containing aromatic diamines can be 40–100 mol% or 50–97 mol%. In aromatic polyether imides, aromatic polyether amide imides, and aromatic polyether amides, based on the total amount of structural units derived from diamine components, the proportion of structural units derived from oxygen-containing aromatic diamines can be 60–89 mol% or 68–82 mol%, the proportion of structural units derived from siloxane diamines can be 1–10 mol% or 3–7 mol%, and the proportion of structural units derived from α,ω-diaminoalkanes can be 10–30 mol% or 15–25 mol. In aromatic polyetherimides, aromatic polyetheramideimides, and aromatic polyetheramides, based on the total amount of structural units derived from diamine components, the proportion of structural units derived from oxygen-containing aromatic diamines can be 90–99 mol% or 93–97 mol%, and the proportion of structural units derived from siloxane diamines can be 1–10 mol% or 3–7 mol%. In aromatic polyetherimides, aromatic polyetheramideimides, and aromatic polyetheramides, based on the total amount of structural units derived from diamine components, the proportion of structural units derived from oxygen-containing aromatic diamines can be 40–70 mol% or 45–60 mol%, and the proportion of structural units derived from non-oxygen-containing aromatic diamines can be 30–60 mol% or 40–55 mol%.

[0032] Adhesive layers containing thermoplastic resins and low-molecular-weight components are prone to reduced adhesion to the lead frame after heat treatment. Furthermore, according to the inventors, if the low-molecular-weight components contain a high amount of chlorine-containing components, there is a tendency for the adhesion of the adhesive layer 2 to the lead frame to decrease after heat treatment. That is, the peeling performance of the adhesive layer 2 from the lead frame is further improved. It is presumed that the chlorine-containing components volatilize as gaseous components such as hydrogen chloride at high temperatures, and the volatilized gaseous components contribute to a decrease in the adhesion of the adhesive layer to the lead frame. Considering these points, the total chlorine content of the low-molecular-weight components can be 12.5% ​​by mass or more, or 12.5% ​​by mass or more but less than 30% by mass. The total chlorine content of the low molecular weight components can be 13.0% by mass or more, 13.5% by mass or more, 13.8% by mass or more, 14.0% by mass or more, 14.5% by mass or more, 15.0% by mass or more, 15.5% by mass or more, 16.0% by mass or more, 16.5% by mass or more, 17.0% by mass or more, 17.5% by mass or more, 18.0% by mass or more, 18.5% by mass or more, or 19.0% by mass or more. The total chlorine content of the additives can be below 25% by mass or less, below 24% by mass or less, below 23% by mass or less, below 22% by mass or less, below 21% by mass or less, or below 20% by mass.

[0033] In this specification, the total chlorine content of the low-molecular-weight components refers to the proportion of chlorine atoms by mass relative to the total mass of the low-molecular-weight components. The total chlorine content of the low-molecular-weight components is determined, for example, by a method comprising the steps of: ionizing the chlorine atoms contained in the low-molecular-weight components as chloride ions; and quantifying the amount of ionized chloride ions by potentiometric titration with silver nitrate. This determination is performed, for example, according to the method described in JIS K-7243-3. Alternatively, the total chlorine content can be determined by ion chromatography. In this case, the total chlorine content is determined, for example, by a method comprising the steps of: burning the low-molecular-weight components; recovering chlorine atoms from the combustion gases formed by combustion into the sample; and analyzing the sample by ion chromatography.

[0034] The low-molecular-weight component may contain chlorine atoms in an amount within the range specified above for total chlorine content. At least a portion of the chlorine atoms in the additive may be covalently bonded to other atoms in the low-molecular-weight component compound.

[0035] At least a portion of the low-molecular-weight compound constituting the low-molecular-weight component may be an epoxy compound having one or more epoxy groups (or glycidyl ether groups) and a molecular weight of less than 1000. Specific examples of such epoxy compounds include sorbitol polyglycidyl ether and polyethylene glycol diglycidyl ether. Sorbitol polyglycidyl ether is a compound having sorbitol residues and two or more glycidyl ether groups bonded thereto, and may be a mixture of two or more components with different numbers of glycidyl ether groups. The epoxy equivalent of sorbitol polyglycidyl ether may, for example, be 150–200 g / eq. Based on the mass of the low-molecular-weight component, the proportion of the epoxy compound may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, or 99% by mass or more, or may be less than 100% by mass. Based on the mass of the low molecular weight component, the proportion of epoxy compounds can be between 50% and 100% by mass. In particular, the proportion of sorbitol polyglycidyl ether can be within these ranges.

[0036] When the low-molecular-weight component contains an epoxy compound, the low-molecular-weight component may sometimes contain epichlorohydrin, a chloropropanol compound derived from epichlorohydrin, or both, as a component containing chlorine atoms. A portion of the epoxy compound (e.g., sorbitol polyglycidyl ether) may have a chloropropanol group.

[0037] From the perspective of lead frame peel performance after undergoing a 400°C heat treatment, the content of low molecular weight components relative to 100 parts by mass of thermoplastic resin can be 3 parts by mass or more and 30 parts by mass or less. The content of low molecular weight components relative to 100 parts by mass of thermoplastic resin can be 4 parts by mass or more, 5 parts by mass or more, or 6 parts by mass or more, or it can be 25 parts by mass or less, 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less. From the same perspective, the content of epoxy compounds or sorbitol polyglycidyl ether relative to 100 parts by mass of thermoplastic resin can be 3 parts by mass or more and 30 parts by mass or less, or it can be 4 parts by mass or more, 5 parts by mass or more, or 6 parts by mass or more, or it can be 25 parts by mass or less, 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less.

[0038] For the same reasons mentioned above, the total chlorine content of adhesive layer 2 also affects the peeling performance of the lead frame after undergoing a thermal process at 400°C. From this perspective, the total chlorine content in adhesive layer 2, based on the mass of adhesive layer 2, can be 1.11% by mass or more, or 1.11% by mass or more but less than 3.00% by mass. The total chlorine content in adhesive layer 2, based on the mass of adhesive layer 2, can be 1.15% by mass or more, 1.20% by mass or more, 1.25% by mass or more, 1.30% by mass or more, 1.35% by mass or more, 1.40% by mass or more, 1.45% by mass or more, 1.50% by mass or more, 1.55% by mass or more, 1.60% by mass or more, 1.65% by mass or more, or 1.70% by mass or less, or it can be less than 2.90% by mass or less, 2.80% by mass or less, 2.70% by mass or less, 2.60% by mass or less, 2.50% by mass or less, 2.40% by mass or less, 2.30% by mass or less, 2.20% by mass or less, 2.10% by mass or less, 2.00% by mass or less, 1.90% by mass or less, 1.80% by mass or less, or 1.75% by mass or less. When the low molecular weight component contains a component containing chlorine atoms, the total chlorine content in the adhesive layer 2 can be adjusted within a specified range according to the content of the low molecular weight component.

[0039] The total chlorine content in adhesive layer 2 can be determined using the same method as the total chlorine content in the low molecular weight components. The total chlorine content in the low molecular weight components and the total chlorine content calculated using the following formula based on the content (parts by mass) of the low molecular weight components relative to the content of the thermoplastic resin can be within the above-mentioned range.

[0040] Total chlorine content [mass%] in the adhesive layer = {(content of low molecular weight components [parts by mass]) × (total chlorine content in low molecular weight components [mass%])} / (total mass parts of the adhesive layer containing 100 parts by mass of thermoplastic resin) The adhesive layer 2 may further contain one or more coupling agents. The coupling agent may also be a silane coupling agent. A silane coupling agent may be of the following formula (I): The compound represented. In formula (I), R 1 R 2 and R 3 Each of the following can be independently represented: an alkoxy group with 1 to 3 carbon atoms, an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms. X represents a group containing a reactive functional group.

[0041] As R 1 R 2 or R 3 Examples of alkoxy groups with 1 to 3 carbon atoms include methoxy, ethoxy, and propoxy. As R... 1 R 2 or R 3 Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl. As R 1 R 2 or R 3 Examples of aryl groups with 6 to 12 carbon atoms include phenyl, tolyl, xylyl, and naphthyl.

[0042] The reactive functional group of X can be, for example, an amino group, an isocyanate group, an amide group, or an epoxy group. X can be one of the following formulas (IIa), (IIb), (IIc), (IId), or (IIe): The groups represented. In these formulas, R 4 R 5 and R 6 It represents an alkyl group with 1 to 6 carbon atoms, an aryl group with 6 to 12 carbon atoms, or a hydrogen atom. Indicates the bonding site with a carbon atom. R 4 R 5 and R 6 It can be an alkyl group with 1 to 6 carbon atoms selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and hexyl, or an aryl group with 6 to 12 carbon atoms selected from phenyl, tolyl, xylyl and naphthyl.

[0043] Examples of silane coupling agents in which X is a group represented by formula (IIa) include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-phenylaminopropyltriethoxysilane, 3-phenylaminopropylmethyldimethoxysilane, 3-phenylaminopropylmethyldiethoxysilane, 3-methylaminopropyltrimethoxysilane, 3-methylaminopropyltriethoxysilane, 3-ethylaminopropyltrimethoxysilane, and 3-ethylaminopropyltriethoxysilane.

[0044] Examples of silane coupling agents in which X is a group represented by formula (IIb) include 3-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-(2-phenylaminoethyl)-3-aminopropyltrimethoxysilane, 3 -(2-phenylaminoethyl)-3-aminopropyltriethoxysilane, 3-(2-phenylaminoethyl)-3-aminopropylmethyldimethoxysilane, 3-(2-methylaminoethyl)-3-aminopropyltrimethoxysilane, 3-(2-methylaminoethyl)-3-aminopropyltriethoxysilane, 3-(2-ethylaminoethyl)-3-aminopropyltrimethoxysilane and N-(2-ethylaminoethyl)-3-aminopropyltriethoxysilane.

[0045] Examples of silane coupling agents in which X is a group represented by formula (IIc) include 3-isocyanate-propyltrimethoxysilane, 3-isocyanate-propylmethyldimethoxysilane, 3-isocyanate-propyltriethoxysilane and 3-isocyanate-propylmethyldiethoxysilane.

[0046] Examples of silane coupling agents in which X is a group represented by formula (IId) include 3-ureopropyltrimethoxysilane, 3-ureopropylmethyldimethoxysilane, 3-ureopropyltriethoxysilane, 3-ureopropylmethyldiethoxysilane, 3-(3-phenylureo)propyltriethoxysilane, 3-(3-methylureo)propyltriethoxysilane, 3-(3-ethylureo)propyltriethoxysilane, and 3-(3-propylureo)propyltriethoxysilane. Oxysilane, 3-(3-butylureo)propyltriethoxysilane, 3-(3-hexylureo)propyltriethoxysilane, 3-(3-phenylureo)propyltrimethoxysilane, 3-(3-methylureo)propyltrimethoxysilane, 3-(3-ethylureo)propyltrimethoxysilane, 3-(3-propylureo)propyltrimethoxysilane, 3-(3-butylureo)propyltrimethoxysilane and 3-(3-hexylureo)propyltrimethoxysilane.

[0047] Examples of silane coupling agents in which X is a group represented by formula (IIe) include 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltriethoxysilane and 3-epoxypropoxypropylmethyldiethoxysilane.

[0048] The content of the coupling agent relative to 100 parts by mass of the thermoplastic resin can be 1 to 40 parts by mass. If the content of the silane coupling agent is 1% by mass or more, it tends to further improve the peel performance from the lead frame after heat treatment. If the content of the coupling agent is 40% by mass or less, it is less likely to cause gelation, viscosity decrease, etc., of the varnish used to form the adhesive layer 2, and it is easier to manufacture a temporary protective film. From the same point of view, the content of the coupling agent relative to 100 parts by mass of the thermoplastic resin can be 1 to 35 parts by mass, 2 to 35 parts by mass, 3 to 30 parts by mass, more than 5 parts by mass and less than 35 parts by mass, more than 5 parts by mass and less than 30% by mass, or more than 5 parts by mass and less than 20 parts by mass.

[0049] The adhesive layer 2 may further include fillers. Examples of fillers include ceramic powder, glass powder, silver powder, copper powder, resin particles, and rubber particles. The filler content relative to 100 parts by weight of the thermoplastic resin can be 0–30 parts by weight, 1–30 parts by weight, or 5–15 parts by weight.

[0050] The total content of thermoplastic resin, low molecular weight components and coupling agent in adhesive layer 2, or the total content of thermoplastic resin, low molecular weight components, coupling agent and filler, can be 90 to 100% by mass, based on the mass of adhesive layer 2.

[0051] From the viewpoint of more easily suppressing the curling of the temporary protective film, the thickness of the adhesive layer 2 can be less than 20 μm, less than 18 μm, less than 16 μm, less than 14 μm, less than 12 μm, less than 10 μm, less than 9 μm, or less than 8 μm. The thickness of the adhesive layer 2 can be more than 1 μm, more than 2 μm, more than 3 μm, more than 4 μm, more than 5 μm, more than 6 μm, more than 7 μm, or more than 8 μm. The thickness of the adhesive layer 2 can be more than 1 μm and less than 20 μm.

[0052] The support film 1 can be, for example, a film of at least one polymer selected from the group consisting of aromatic polyimide, aromatic polyamide, aromatic polyamide-imide, aromatic polysulfone, aromatic polyethersulfone, polyphenylene sulfide, aromatic polyetherketone, polyarylate, aromatic polyetheretherketone, and polyethylene naphthalate. The support film 1 can be a film-like material made of copper, aluminum, stainless steel, or nickel. When the support film 1 is a polymer film, its surface can be treated by methods such as alkali treatment, silane coupling treatment, physical treatment such as sanding treatment, plasma treatment, and corona treatment.

[0053] The thickness of the support film 1 can be, for example, 5 to 100 μm or less, or 5 to 50 μm or less. The ratio of the thickness T2 of the adhesive layer to the thickness T1 of the support film, T2 / T1, can be 0.5 or less, 0.3 or less, or 0.2 or less.

[0054] The non-adhesive layer 3 is a resin layer that does not substantially have adhesive (or pressure-sensitive adhesive) to the lead frame at temperatures ranging from 0 to 270°C. The non-adhesive layer can be a resin layer that does not easily soften at high temperatures; for example, a resin layer with a high glass transition temperature can function as a non-adhesive layer.

[0055] The resin layer 3, serving as the non-adhesive layer, comprises a thermoplastic resin, a thermosetting resin (cured product), or a combination thereof. The thermoplastic resin may have amide, ester, imide, oxygen, or sulfonyl groups. The thermosetting resin may, for example, be an epoxy resin, phenolic resin, or bismaleimide resin. In the case of a combination of thermoplastic and thermosetting resins, the amount of thermosetting resin relative to 100 parts by weight of the thermoplastic resin content may be 5 to 100 parts by weight or 20 to 70 parts by weight.

[0056] The non-adhesive layer 3 may contain fillers (e.g., ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles), coupling agents, etc. The filler content in the non-adhesive layer 3 may be 1–30 parts by weight or 5–15 parts by weight per 100 parts by weight of resin. The coupling agent content may be 1–20 parts by weight or 2–15 parts by weight per 100 parts by weight of resin.

[0057] The peel strength of the non-adhesive layer 3 relative to the brass mold at 90 degrees can be less than 5 N / m or less than 1 N / m at 25°C. This peel strength is measured after the non-adhesive layer 3 is pressed into the brass mold at a temperature of 250°C and a pressure of 8 MPa for 10 seconds.

[0058] The thickness of the non-adhesive layer 3 can be, for example, less than 10 μm, less than 9 μm, less than 8 μm, or less than 7 μm. The thickness of the non-adhesive layer can be, for example, more than 1 μm, more than 2 μm, more than 3 μm, more than 4 μm, more than 5 μm, or more than 6 μm. There is no particular limitation on the thickness of the non-adhesive layer, for example, it can be 1 to 10 μm or 1 to 8 μm.

[0059] A temporary protective film can be manufactured, for example, by a method comprising the steps of: preparing a low-molecular-weight component; mixing the low-molecular-weight component with a thermoplastic resin and a solvent to form a varnish; forming a film containing the varnish on a support film 1; and forming an adhesive layer by removing the solvent from the film. The film containing the varnish can be formed, for example, by applying the varnish to the support film. A non-adhesive layer can also be formed using the same method as the adhesive layer.

[0060] Semiconductor package manufacturing method The temporary protective film illustrated above can be used to manufacture semiconductor packages. The manufactured semiconductor package can be, for example, a Non-Lead Type Package, having a lead frame, a semiconductor element mounted on the lead frame, and a sealing layer that seals the semiconductor element on the semiconductor element side of the lead frame, with the back of the lead frame exposed for external connectivity. Specific examples include QFN (Quad Flat Non-leaded Package) and SON (Small Outline Non-leaded Package).

[0061] Figure 3 and Figure 4 This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor package. Figure 5 It means through Figure 3 and Figure 4 This is a cross-sectional view of an example of a semiconductor package obtained by the manufacturing method. The following descriptions of each process will be provided with reference to the accompanying drawings as needed.

[0062] Figure 3 and Figure 4The method described includes the following steps in sequence: attaching a temporary protective film 10 to one side (the back side) of the lead frame 11 having chip pads 11a and inner leads 11b, with its adhesive layer in contact with the lead frame 11; mounting a semiconductor element 14 on the side of the chip pads 11a opposite to the temporary protective film 10; providing a wire 12 connecting the semiconductor element 14 to the inner leads 11b; forming a sealing layer 13 to seal the semiconductor element 14 and the wire 12, thereby obtaining a temporarily protected encapsulated molded body 20 having the lead frame 11, the semiconductor element 14, and the sealing layer 13; and peeling the temporary protective film 10 from the encapsulated molded body 20. The temporarily protected encapsulated molded body consists of the encapsulated molded body 20 and the temporary protective film 10.

[0063] The process of attaching the temporary protective film 10 to the lead frame 11 may include heating and pressurizing the temporary protective film 10 disposed on the lead frame 11. The heating temperature may be above 150°C, above 180°C, or above 200°C, or below 400°C. The pressure may be 0.5–30 MPa, 1–20 MPa, or 3–15 MPa. The heating and pressurizing time may be 0.1–60 seconds, 1–30 seconds, or 3–20 seconds.

[0064] The lead frame 11 can be made of, for example, an iron-based alloy such as alloy 42, copper, or a copper-based alloy. The lead frame 11 can have a molded body made of copper or a copper-based alloy and a cladding layer such as palladium, gold, or silver covering its surface.

[0065] Semiconductor element 14 is typically bonded to chip pad 11a using an adhesive (e.g., silver paste). After the semiconductor element 14 is bonded to the chip pad 11a, reflow bonding (CuClip, etc.) can be performed at a maximum temperature of 250–440°C or 250–400°C for 1–30 minutes.

[0066] There are no particular limitations on the wire 12; for example, it can be a gold wire, a copper wire, or a palladium-coated copper wire. For example, it can be heated at 200–260°C or 350–260°C for 3–60 minutes, and ultrasonic waves and pressing pressure can be used to bond the semiconductor element 14 and the inner pin 11b to the wire 12.

[0067] The sealing layer 13 is formed by sealing molding using a sealing material. By sealing molding, a sealed molded body 20 can be obtained having a sealing layer 13 that seals multiple semiconductor elements 14 together. During sealing molding, a temporary protective film 10 is provided to prevent the sealing material from winding into the back side of the lead frame 11.

[0068] The temperature (temperature of the sealing material) during the formation of the sealing layer 13 can also be 140–200°C or 160–180°C. The pressure during the formation of the sealing layer can also be 6–15 MPa or 7–10 MPa. The sealing time can be 1–5 minutes or 2–3 minutes.

[0069] The formed sealing layer 13 can be cured by heating as needed. The heating temperature for curing the sealing layer 13 can be 150-200℃ or 160-180℃. The heating time for curing the sealing layer 13 can be 4-7 hours or 5-6 hours.

[0070] The sealing material may include, for example, one or more epoxy resins selected from cresol phenolic epoxy resin, phenolic epoxy resin, biphenyl epoxy resin, and naphthol phenolic epoxy resin. The sealing material may also include fillers, flame-retardant substances such as bromine compounds, and wax components.

[0071] After the sealing layer 13 is formed, the temporary protective film 10 is peeled off from the lead frame 11 and the sealing layer 13 of the obtained sealing mold 20. In the case of curing the sealing layer 13, the temporary protective film 10 can be peeled off at any time before or after the curing of the sealing layer 13.

[0072] The temperature at which the temporary protective film 10 is heated in order to peel it off from the sealed molded body 20 can be 0–250°C, 100–200°C, or 150–250°C.

[0073] After the temporary protective film 10 is peeled off from the lead frame 11, if a portion of the adhesive layer remains on the lead frame 11 and the sealing layer 13, it can be removed. The residual adhesive layer can be removed by mechanical brushing or by solvent. Solvents can be, for example, N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, or dimethylformamide.

[0074] When the lead frame includes multiple patterns with chip pads and internal pins, the encapsulation molding body 20 can be divided as needed to obtain multiple pieces, each with one semiconductor element. Figure 5 The semiconductor package 100. That is, the lead frame 11 has a plurality of chip pads 11a, and a semiconductor element 14 is mounted on each of the plurality of chip pads 11a. The manufacturing method according to one embodiment further includes the following steps: after peeling off the temporary protective film 10 (or 10') from the encapsulation molded body 20, the encapsulation molded body 20 is divided to obtain a semiconductor package 100 having one chip pad 11a and a semiconductor element 14.

[0075] A long temporary protective film can be wound onto a core, and a semiconductor package can be manufactured while the temporary protective film is being released from the resulting reel. The reel then contains a core and the temporary protective film described in the above-described embodiment wound onto the core.

[0076] Figure 6 This is a three-dimensional diagram representing an example of a reel body. Figure 6 The reel body 30 shown includes a core 31, a temporary protective film 10 wound onto the core 31, and a side plate 32. The width (length in the direction orthogonal to the winding direction) of the core 31 and the temporary protective film 10 can be 0.001 cm or more, 0.005 cm or more, or 0.008 cm or more, or less than 0.03 cm. For example, the width (length in the direction orthogonal to the winding direction) of the core 31 and the temporary protective film 10 can be 0.001 cm or more and less than 0.03 cm, 0.005 cm or less and less than 0.03 cm, or 0.008 cm or more and less than 0.03 cm.

[0077] Temporary protective film can be provided as a packaging material for containing the reel in a packaging bag. Figure 7 Examples representing packaging. For example... Figure 7 As shown, the packaging body 50 includes a reel body 30 and a packaging bag 40 for containing the reel body 30. The reel body 30 is usually contained individually in the packaging bag, but multiple (e.g., 2 to 3) reels 30 can also be contained in one packaging bag 40.

[0078] The packaging bag 40 can be formed from a resin film. The packaging bag 40 can be formed from a resin film having an aluminum layer, i.e., a composite film. Specific examples of the packaging bag 40 include plastic bags with an aluminum coating. Materials for the resin film include plastics such as polyethylene, polyester, vinyl chloride, and polyethylene terephthalate. The reel body 30 can, for example, be contained within the packaging bag under vacuum packaging conditions. The packaging body 50 is not limited to vacuum packaging.

[0079] The packaging bag 40 may contain a desiccant along with the reel body 30. Silica gel may be an example of a desiccant. The packaging body 50 may further include cushioning material that wraps around the packaging bag 40 containing the reel body 30.

[0080] Packaging body 50 can be provided as packaging material contained in a packaging box. Figure 8 Examples of packaging materials. For example... Figure 8 As shown, the packaging 70 includes a packaging body 50 and a carton 60 for housing the packaging body 50. One or more packaging bodies 50 are housed in the carton 60. The carton 60 can be, for example, corrugated cardboard.

[0081] Semiconductor devices manufactured using the temporary protective film involved in this invention have advantages in terms of high density, small area, and thinness, and can be applied to electronic devices such as mobile phones, smartphones, computers, and tablets.

[0082] Example The present invention is not limited to the following embodiments.

[0083] 1. Low molecular weight components The following sorbitol polyglycidyl ether products (manufactured by Nagase ChemteX Corporation) are used as low molecular weight ingredients.

[0084] EX-622 (Total chlorine content: 19.4% by mass) EX-612 (Total chlorine content: 13.8% by mass) EX-614B (Total chlorine content: 10.1% by mass) EX-614 (Total chlorine content: 11.3% by mass) 2. Preparation of temporary protective film Temporary protective films of examples or comparative examples having an adhesive layer containing each component were prepared according to the proportions (parts by mass) shown in Table 1, and were prepared according to the following steps. Table 1 also shows the total chlorine content in each low molecular weight component and the total chlorine content in the adhesive layer calculated based on the content of the low molecular weight component.

[0085] Aromatic polyether amide imide was prepared by condensing 270.9 g (0.63 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 67.0 g (0.27 mol) of 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and 187.3 g (0.89 mol) of trimellitic anhydride acyl chloride. 100 parts by weight of this aromatic polyether amide imide, 10 parts by weight of a low molecular weight component, and 3 parts by weight of a silane coupling agent (3-epoxypropoxypropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd., trade name: SH6040) were dissolved in N-methylpyrrolidone to obtain a varnish for forming an adhesive layer.

[0086] The obtained varnish was applied to one side of the support film. A polyimide film (thickness: 25 μm, manufactured by UBE Corporation, trade name: UPILEX SGA) with a chemically treated surface was used as the support film. The coating on the support film was dried by heating at 100°C for 10 minutes and then at 200°C for 10 minutes to form an adhesive layer with a thickness of 2 μm, thus obtaining a temporary protective film consisting of the support film and the adhesive layer.

[0087] 3. Peel strength (1) Before heat treatment The temporary protective film was applied to the copper plate surface with the adhesive layer facing towards the copper plate, under conditions of 235°C, 6MPa, and 10 seconds. Then, the 90° peel strength between the adhesive layer and the copper plate was measured at 200°C with a peeling speed of 300 mm / min.

[0088] (2) After heat treatment A temporary protective film was applied to the copper plate surface with the adhesive layer facing towards the copper plate, under conditions of 235°C, 6 MPa, and 10 seconds. Next, the copper plate and the temporary protective film attached to it were placed in an oven at 180°C for 1 hour. Subsequently, the copper plate and the temporary protective film were removed from the oven and subjected to heat treatment in a nitrogen atmosphere. The heat treatment conditions were: heating to a maximum temperature of 400°C at a rate of 2°C / second, and holding at 400°C for 1 second. After heat treatment, the 90° peel strength between the adhesive layer and the copper plate at 200°C was measured at a peel speed of 300 mm / min.

[0089] [Table 1]

[0090] The evaluation results are shown in Table 1. The temporary protective films of Examples 1 and 2 can be properly attached to the lead frame, and it was confirmed that peeling is easier after undergoing a high-temperature thermal process of about 400°C.

[0091] Symbol Explanation 1-Support film, 2-Adhesive layer, 3-Non-adhesive layer, 10, 10'-Temporary protective film, 11-Lead frame, 11a-Chip pad, 11b-Inner pin, 12-Wire, 13-Encapsulation layer, 14-Semiconductor element, 20-Encapsulation molded body, 30-Reel body, 31-Core, 32-Side plate, 40-Packaging bag, 50-Packaging body, 60-Packaging box, 70-Packaging material, 100-Semiconductor package.

Claims

1. A temporary protective film for semiconductor encapsulation, comprising a support film and an adhesive layer disposed on one or both sides of the support film, for temporarily protecting the side of the lead frame opposite to the semiconductor element during the encapsulation process of forming an encapsulation layer for encapsulating a semiconductor element mounted on a chip pad of a leadframe. The adhesive layer comprises thermoplastic resin and compounds with a molecular weight of less than 1000, i.e., low molecular weight components. The total chlorine content in the low molecular weight component is 12.5% ​​by mass or more.

2. The temporary protective film for semiconductor encapsulation according to claim 1, wherein, The content of the low molecular weight component is more than 3 parts by mass and less than 20 parts by mass relative to the content of the thermoplastic resin (100 parts by mass).

3. A temporary protective film for semiconductor encapsulation, comprising a support film and an adhesive layer disposed on one or both sides of the support film, for temporarily protecting the side of the lead frame opposite to the semiconductor element during the encapsulation process of forming an encapsulation layer for encapsulating a semiconductor element mounted on a chip pad of a leadframe. The adhesive layer comprises thermoplastic resin and compounds with a molecular weight of less than 1000, i.e., low molecular weight components. The total chlorine content in the adhesive layer is 1.11% by mass or more.

4. The temporary protective film for semiconductor encapsulation according to any one of claims 1 to 3, wherein, The low molecular weight component comprises an epoxy compound having one or more epoxy groups.

5. A method for manufacturing a temporary protective film for semiconductor encapsulation, the temporary protective film comprising a support film and an adhesive layer disposed on one or both sides of the support film, for temporarily protecting the side of the lead frame opposite to the semiconductor element during encapsulation of an encapsulation layer for encapsulating a semiconductor element mounted on a chip pad of a leadframe. The method includes the following steps: Prepare compounds with a molecular weight of less than 1000, i.e., low molecular weight components; The low molecular weight component is mixed with a thermoplastic resin and a solvent to form a varnish; A film containing the varnish is formed on the support film; and The adhesive layer is formed by removing the solvent from the membrane; The total chlorine content in the low molecular weight component is 12.5% ​​by mass or more.

6. A lead frame with a temporary protective film, comprising: Leadframe with chip pads; and Temporary protective film for semiconductor encapsulation as described in any one of claims 1 to 3 The temporary protective film is attached to one surface of the lead frame with the adhesive layer of the temporary protective film in contact with the lead frame.

7. A temporary protective sealed molded body, comprising: Leadframe with chip pads; A semiconductor element is mounted on the chip pad on one side of the lead frame; Encapsulating layer for sealing the semiconductor device; and Temporary protective film for semiconductor encapsulation as described in any one of claims 1 to 3 The temporary protective film is attached to the side of the lead frame opposite to the semiconductor element, with the adhesive layer of the temporary protective film in contact with the lead frame.

8. A method for manufacturing a semiconductor package, comprising the following steps in sequence: On one side of a lead frame having chip pads, a temporary protective film for semiconductor encapsulation as described in any one of claims 1 to 3 is attached in the direction that the adhesive layer of the temporary protective film contacts the lead frame. A semiconductor element is mounted on the side of the chip pad opposite to the temporary protective film; A sealing layer is formed to seal the semiconductor element, thereby obtaining a sealed molded body with temporary protection for the lead frame, the semiconductor element, and the sealing layer; and The temporary protective film is peeled off from the sealed molded body.

9. The method according to claim 8, wherein, The lead frame has a plurality of chip pads, on each of the plurality of chip pads, a semiconductor element is mounted. The method further includes the following steps: after peeling the temporary protective film from the encapsulation molded body, the encapsulation molded body is divided to obtain a semiconductor package having one of the chip pads and the semiconductor element.

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