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

Abstract

A temporary protection film for semiconductor encapsulation which comprises a substrate film and an adhesive layer. The adhesive layer comprises a thermoplastic resin and a low-molecular-weight additive having a molecular weight less than 1,000. The adhesive layer has been configured so that when the temporary protection film for semiconductor encapsulation is applied to a surface of a copper sheet with the adhesive layer in contact with the copper sheet to form a laminate consisting of the copper sheet and the temporary protection film for semiconductor encapsulation and the laminate is subsequently heated at 180°C for 1 hour, then the surface of the copper sheet has a proportion of oxygen atoms of X1 and when the laminate is thereafter heated at 400°C for 2 minutes, then the surface of the copper sheet has a proportion of oxygen atoms of X2, X2 being less than X1.

Description

Technical Field

[0001] The present invention relates to a temporary protection film for semiconductor encapsulation molding, a method for manufacturing the same, a lead frame with a temporary protection film, a temporarily protected encapsulation molded body, and a method for manufacturing a semiconductor package.

Background Art

[0002] In a semiconductor package, a structure may be adopted in which a sealing layer is formed only on the semiconductor element side of the lead frame and the back surface of the lead frame is exposed (Patent Documents 1 and 2). In manufacturing a semiconductor package having this structure, in order to prevent the sealing resin from flowing around the back surface of the lead frame during encapsulation molding, the back surface of the lead frame may be temporarily protected by attaching a temporary protection film. The temporary protection film is peeled off from the lead frame after the sealing layer is formed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An assembly process for manufacturing a semiconductor package may require heating at a high temperature reaching about 400°C for reflow connection or the like. However, when the temporary protection film attached to the lead frame undergoes such a high-temperature heat history, the temporary protection film may adhere strongly to the lead frame and the sealing layer, and it may not be possible to peel the temporary protection film from the lead frame, or it may be difficult to peel it cleanly from the lead frame without leaving residues.

[0005] The present disclosure relates to a temporary protection film for semiconductor encapsulation molding that can be attached to a lead frame with an appropriate adhesive strength and can be easily peeled off after receiving a thermal history at a high temperature of about 400°C.

Means for Solving the Problems

[0006] One aspect of the present disclosure provides a temporary protection film including a support film and an adhesive layer provided on one or both surfaces of the support film. This temporary protection film is used to temporarily protect the surface of the lead frame opposite to the semiconductor element during encapsulation molding for forming an encapsulation layer that encapsulates the semiconductor element mounted on the die pad of the lead frame. In other words, one aspect of the present disclosure provides an application for temporarily protecting the surface of the lead frame opposite to the semiconductor element during encapsulation molding for forming an encapsulation layer that encapsulates the semiconductor element mounted on the die pad of the lead frame. The adhesive layer is configured such that when the temporary protection film for semiconductor encapsulation molding is attached to the surface of a copper plate with the adhesive layer in contact with the copper plate to form an attached body composed of the copper plate and the temporary protection film for semiconductor encapsulation molding, and then the attached body is heated at 180°C for 1 hour, the ratio of oxygen atoms on the surface of the copper plate is X1, and then the attached body is subjected to a heat treatment of further heating at 400°C for 2 minutes and the ratio of oxygen atoms on the surface of the copper plate is X2, X2 is smaller than X1. In other words, when the protection film for semiconductor encapsulation molding is attached to the surface of a copper plate with the adhesive layer in contact with the copper plate, and then the attached body composed of the copper plate and the temporary protection film for semiconductor encapsulation molding is subjected to a heat treatment of heating at 180°C for 1 hour and then at 400°C for 2 minutes in sequence, the ratio of oxygen atoms on the surface of the copper plate after heating at 400°C for 2 minutes is smaller than the ratio of oxygen atoms on the surface of the copper plate after heating at 180°C for 1 hour.

[0007] Another aspect of the present disclosure provides a method for manufacturing a temporary protection film including a support film and an adhesive layer provided on one or both surfaces of the support film. The temporary protection film to be manufactured is a protection film for semiconductor encapsulation molding used to temporarily protect the surface of the lead frame opposite to the semiconductor element during encapsulation molding for forming an encapsulation layer that encapsulates the semiconductor element mounted on the die pad of the lead frame. The method includes attaching an adhesive layer composed of 100 parts by mass of a thermoplastic resin and 5 to 20 parts by mass of a low molecular additive to the surface of a copper plate to form an adherend composed of the copper plate and the adhesive layer, where the ratio of oxygen atoms on the surface of the copper plate after heating the adherend at 180°C for 1 hour is X1, and then, when the ratio of oxygen atoms on the surface of the copper plate after subjecting the adherend to a heat treatment of further heating at 400°C for 2 minutes is X2, selecting the low molecular additive such that X2 is smaller than X1, and forming an adhesive layer including the thermoplastic resin and the selected low molecular additive on one or both surfaces of the support film. In other words, the method includes subjecting an adherend obtained by attaching an adhesive layer composed of 100 parts by mass of a thermoplastic resin and 5 to 20 parts by mass of a low molecular additive to the surface of a copper plate to a heat treatment of heating at 180°C for 1 hour and then at 400°C for 2 minutes in sequence, and selecting a low molecular additive such that the ratio of oxygen atoms on the surface of the copper plate after heating at 400°C for 2 minutes is smaller than the ratio of oxygen atoms on the surface of the copper plate after heating at 180°C for 1 hour, and forming an adhesive layer including the thermoplastic resin and the selected low molecular additive on one or both surfaces of the support film.

[0008] Yet another aspect of the present disclosure provides a lead frame with a temporary protection film including a lead frame having a die pad and the temporary protection film for semiconductor encapsulation molding. The temporary protection film is attached to one surface of the lead frame with the adhesive layer of the temporary protection film in contact with the lead frame.

[0009] Yet another aspect of the present disclosure provides a temporarily protected encapsulated molded body, comprising a lead frame having a die pad, a semiconductor element mounted on the die pad on one surface side of the lead frame, an encapsulation layer encapsulating the semiconductor element, and the temporary protection film for semiconductor encapsulation molding. The temporary protection film is attached to the surface of the lead frame opposite to the semiconductor element with the adhesive layer of the temporary protection film in contact with the lead frame.

[0010] Yet another aspect of the present disclosure relates to a method for manufacturing a semiconductor package, comprising the steps of: attaching the temporary protection film for semiconductor encapsulation molding to one surface of a lead frame having a die pad with the adhesive layer of the temporary protection film in contact with the lead frame; mounting a semiconductor element on the surface of the die pad opposite to the temporary protection film; forming an encapsulation layer for encapsulating the semiconductor element to obtain a temporarily protected encapsulated molded body having the lead frame, the semiconductor element, and the encapsulation layer; and peeling the temporary protection film from the encapsulated molded body in this order.

Advantages of the Invention

[0011] According to one aspect of the present disclosure, there is provided a temporary protection film for semiconductor encapsulation molding that can be attached to a lead frame with an appropriate adhesive force and can be easily peeled off after receiving a thermal history at a high temperature of about 400°C.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0013] The present invention is not limited to several embodiments exemplified below. The upper limit value and the lower limit value of the numerical range described in this specification can be arbitrarily combined. The numerical values described in the examples can also be used as the upper limit value or the lower limit value of the numerical range.

[0014] Temporary protection film FIG. 1 is a cross-sectional view showing a temporary protection film according to an embodiment. The temporary protection film 10 shown in FIG. 1 is composed of a support film 1 and an adhesive layer 2 provided on one surface of the support film 1. Adhesive layers may be formed on both surfaces of the support film 1. FIG. 2 is also a cross-sectional view showing a temporary protection film according to an embodiment. The temporary protection film 10' in FIG. 2 has a support film 1, an adhesive layer 2 provided on one main surface of the support film 1, and a non-adhesive layer 3 provided on the other main surface of the support film 1. These temporary protection films can be used as a temporary protection film for semiconductor encapsulation molding for temporarily protecting a lead frame during encapsulation molding by attaching them to the back surface of the lead frame (the surface opposite to the surface on which the semiconductor element is mounted) in the process of forming an encapsulation layer for encapsulating a semiconductor element mounted on a die pad of the lead frame.

[0015] The adhesive layer 2 contains a thermoplastic resin and a low molecular additive.

[0016] The thermoplastic resin may contain at least one selected from the group consisting of aromatic polyether amideimide, aromatic polyetherimide, aromatic polyether amide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamideimide, aromatic polyether, and aromatic polyesterimide. From the viewpoints of heat resistance and adhesiveness, the thermoplastic resin may be at least one selected from the group consisting of aromatic polyether amideimide, aromatic polyetherimide, and aromatic polyether amide, and may be aromatic polyether amideimide.

[0017] The aromatic polyether amideimide is a polycondensate formed from an acid component containing an aromatic tricarboxylic acid or a reactive derivative thereof and an amine component containing an aromatic diamine, and at least one of the aromatic tricarboxylic acid or the aromatic diamine contains a compound having a plurality of aromatic groups and an oxy group (-O-) that binds the aromatic groups to each other, and can be a polycondensate. The aromatic polyetherimide is a polycondensate formed from an acid component containing an aromatic tetracarboxylic acid or a reactive derivative thereof and an amine component containing an aromatic diamine, and at least one of the aromatic tetracarboxylic acid or the aromatic diamine contains a compound having a plurality of aromatic groups and an oxy that binds the aromatic groups to each other, and can be a polycondensate. The aromatic polyether amide is a polycondensate formed from an acid component containing an aromatic dicarboxylic acid or a reactive derivative thereof and an amine component containing an aromatic diamine, and at least one of the aromatic dicarboxylic acid or the aromatic diamine contains a compound having a plurality of aromatic groups and an oxy that binds the aromatic groups to each other, and can be a polycondensate. The reactive derivative of the carboxylic acid may be, for example, an acid anhydride or an acid chloride.

[0018] Aromatic polyether amide imide and aromatic polyamide imide may contain structural units derived from trimellitic acid or its reactive derivatives. Aromatic polyimide and aromatic polyether imide may contain structural units derived from pyromellitic acid, polynuclear aromatic tetracarboxylic acid, or reactive derivatives thereof. Examples of polynuclear aromatic tetracarboxylic acids include bisphenol A bistrimellitate and oxydiphthalic acid. Aromatic polyamide may contain structural units derived from terephthalic acid, isophthalic acid, or reactive derivatives thereof.

[0019] Aromatic polyether amide imide, aromatic polyether imide, and aromatic polyether amide may contain, for example, structural units derived from aromatic diamines having an oxy group 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 imide, aromatic polyether imide, and aromatic polyether amide may further contain structural units derived from other diamines selected from aromatic diamines having no oxy group (for example, (for example 4,4'-methylenebis(2-isopropyl aniline)), siloxane diamine (for example 1,3-bis(3-aminopropyl)tetramethyldisiloxane), and α,ω-diaminoalkane (for example 1,12-diaminododecane, 1,6-diaminohexane).

[0020] In the aromatic polyether amide imide, aromatic polyether imide, and aromatic polyether amide, the proportion of the structural unit derived from the aromatic diamine having an oxy group may be 40 to 100 mol%, or 50 to 97 mol%, based on the total amount of the structural units derived from the diamine component. In the aromatic polyether imide, aromatic polyether amide imide, and aromatic polyether amide, based on the total amount of the structural units derived from the diamine component, the proportion of the structural unit derived from the aromatic diamine having an oxy group may be 60 to 89 mol%, or 68 to 82 mol%, the proportion of the structural unit derived from the siloxane diamine may be 1 to 10 mol%, or 3 to 7 mol%, and the proportion of the structural unit derived from the α,ω-diaminoalkane may be 10 to 30 mol%, or 15 to 25 mol%. In the aromatic polyether imide, aromatic polyether amide imide, and aromatic polyether amide, based on the total amount of the structural units derived from the diamine component, the proportion of the structural unit derived from the aromatic diamine having an oxy group may be 90 to 99 mol%, or 93 to 97 mol%, and the proportion of the structural unit derived from the siloxane diamine may be 1 to 10 mol%, or 3 to 7 mol%. In the aromatic polyether imide, aromatic polyether amide imide, and aromatic polyether amide, based on the total amount of the structural units derived from the diamine component, the proportion of the structural unit derived from the aromatic diamine having an oxy group may be 40 to 70 mol%, or 45 to 60 mol%, and the proportion of the structural unit derived from the aromatic diamine having no oxy group may be 30 to 60 mol%, or 40 to 55 mol%.

[0021] The low-molecular-weight additive is a compound with a molecular weight of less than 1000, and can be selected based on the change in the amount of oxygen on the surface of the copper plate when the adherend obtained by attaching the adhesive layer to the surface of the copper plate is subjected to a predetermined heat treatment. Specifically, when the adherend obtained by attaching an adhesive layer composed of 100 parts by mass of a thermoplastic resin and 5 to 15 parts by mass of a low-molecular-weight additive to the surface of the copper plate is subjected to a heat treatment in which it is heated at 180 °C for 1 hour and then at 400 °C for 2 minutes in an air atmosphere, the ratio X2 of oxygen atoms on the surface of the copper plate after heating at 400 °C for 2 minutes is smaller than the ratio X1 of oxygen atoms on the surface of the copper plate after heating at 180 °C for 1 hour, and the low-molecular-weight additive is selected. The surface of the copper plate in contact with the adhesive layer is oxidized by heating at 180 °C for 1 hour, and a surface containing many oxygen atoms derived from copper oxide is formed. However, depending on the type of low-molecular-weight additive contained in the adhesive layer, the ratio of oxygen atoms on the surface of the copper plate decreases after heating at 400 °C for 2 minutes. According to the findings of the inventors, by adding such a low-molecular-weight additive whose reduction in the ratio of oxygen atoms is observed to the adhesive, the peelability from the lead frame after heat treatment is improved. The decrease in the ratio of oxygen atoms suggests that at least a part of the copper oxide is reduced by the reducing gas generated by the decomposition of the low-molecular-weight additive. For example, it is presumed that the adhesion strength at the interface between the lead frame and the adhesive layer decreases due to the gas generated when the copper oxide is reduced, or due to the aggregation breakdown of the thin copper metal part generated by the reduction of the copper oxide. The reducing gas may be hydrogen, carbon monoxide, or a hydrocarbon gas such as methane, propane, and butane. When the low-molecular-weight additive decomposes by heating and generates a reducing gas, the temperature at which the reducing gas is generated may be 200 °C or higher, 250 °C or higher, 300 °C or higher, or 350 °C or higher, and may also be 550 °C or lower, 500 °C or lower, 450 °C or lower, or 400 °C or lower. The surface of the copper plate used for measuring X1 and X2 may or may not be subjected to plasma irradiation treatment.

[0022] The ratio of oxygen atoms on the surface of the copper plate can be measured, for example, by energy-dispersive X-ray spectroscopy (EDS) or X-ray photoelectron spectroscopy (XPS) of the surface exposed by peeling off the adhesive layer. The ratio of oxygen atoms measured by the EDS method may be 1.2 atomic% or less, 1.1 atomic% or less, 1.0 atomic% or less, 0.9 atomic% or less, 0.8 atomic% or less, 0.7 atomic% or less, 0.6 atomic% or less, 0.5 atomic% or less, 0.4 atomic% or less, 0.3 atomic% or less, or 0.2 atomic% or less at the time points after heat treatment by heating in the order of 1 hour at 180°C and 2 minutes at 400°C. The ratio of oxygen atoms measured by the EDS method may be 0.5 atomic% or less, 0.4 atomic% or less, 0.3 atomic% or less, 0.2 atomic% or less, or 0.1 atomic% or less at the time point before the heat treatment. The ratio of oxygen atoms measured by the EDS method may be 0.5 to 5.0 atomic%, 0.5 to 4.5 atomic%, 0.5 to 4.0 atomic%, 0.5 to 3.5 atomic%, 0.5 to 3.0 atomic%, or 0.5 to 1.0 atomic% at the time point before heating at 400°C after heating at 180°C for 1 hour.

[0023] The low molecular weight additive may be an epoxy compound having one or more epoxy groups (or glycidyl ether groups), polyethylene glycol monoalkyl ether, polyethylene glycol dialkyl ether, or a combination thereof. Specific examples of such epoxy compounds include sorbitol polyglycidyl ether and polyethylene glycol diglycidyl ether.

[0024] Sorbitol polyglycidyl ether is a compound having a residue of sorbitol and two or more glycidyl ether groups bonded thereto, and may be a mixture of two or more components having different numbers of glycidyl ether groups. The epoxy equivalent of sorbitol polyglycidyl ether may be, for example, 150 to 200 g / eq.

[0025] Polyethylene glycol monoalkyl ether and polyethylene glycol dialkyl ether are ether compounds formed from one molecule of polyethylene glycol and one or two molecules of alkyl alcohol. The alkyl alcohol may have 6 to 24 carbon atoms. The alkyl alcohol may be a secondary alcohol. Examples of polyethylene glycol monoalkyl ether and polyethylene glycol dialkyl ether include polyoxyethylene(9) secondary alkyl (C11 - C15) ether.

[0026] From the perspective of peelability from the lead frame after receiving a heat history at 400 °C, the content of the low - molecular - weight additive may be 5 to 30 parts by mass, 5 to 25 parts by mass, 5 to 20 parts by mass, 5 to 15 parts by mass, or 7 to 15 parts by mass with respect to 100 parts by mass of the thermoplastic resin. From the same perspective, the content of sorbitol polyglycidyl ether may be 5 to 20 parts by mass, or 5 to 12 parts by mass with respect to the content of 100 parts by mass of the thermoplastic resin.

[0027] The adhesive layer may further contain one or more coupling agents. The coupling agent may be a silane coupling agent. The silane coupling agent may be a compound represented by the following formula (I):

Chemical formula

[0028] Examples of the alkoxy group having 1 to 3 carbon atoms as R 1 , R 2 or R 3 include methoxy group, ethoxy group, and propoxy group. R 1 , R 2 or R 3Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group. R 1 R 2 or R 3 Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.

[0029] The reactive functional group that X has may be, for example, an amino group, an isocyanate group, an amide group, or an epoxy group. X may be the following formula (IIa), (IIb), (IIc), (IId), or (IIe):

Chemical formula

[0030] 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.

[0031] 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.

[0032] Examples of silane coupling agents in which X is a group represented by formula (IIc) include 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropylmethyldiethoxysilane.

[0033] Examples of the silane coupling agent in which X is a group represented by the formula (IId) include 3-ureidopropyltrimethoxysilane, 3-ureidopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-ureidopropylmethyldiethoxysilane, 3-(3-phenylureido)propyltriethoxysilane, 3-(3-methylureido)propyltriethoxysilane, 3-(3-ethylureido)propyltriethoxysilane, 3-(3-propylureido)propyltriethoxysilane, 3-(3-butylureido)propyltriethoxysilane, 3-(3-hexylureido)propyltriethoxysilane, 3-(3-phenylureido)propyltrimethoxysilane, 3-(3-methylureido)propyltrimethoxysilane, 3-(3-ethylureido)propyltrimethoxysilane, 3-(3-propylureido)propyltrimethoxysilane, 3-(3-butylureido)propyltrimethoxysilane, and 3-(3-hexylureido)propyltrimethoxysilane.

[0034] Examples of the silane coupling agent in which X is a group represented by the formula (IIe) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

[0035] The content of the coupling agent may be 1 to 40 parts by mass with respect to 100 parts by mass of the content of the thermoplastic resin. When the content of the silane coupling agent is 1% by mass or more, the peelability from the lead frame after heat treatment tends to be more improved. When the content of the coupling agent is 40% by mass or less, gelation, viscosity reduction, etc. of the varnish for forming the adhesive layer 2 are less likely to occur, and the temporary protection film can be manufactured more easily. From the same viewpoint, the content of the coupling agent may 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 35 parts by mass or less, more than 5 parts by mass and 30% by mass or less, or more than 5 parts by mass and 20 parts by mass or less with respect to 100 parts by mass of the content of the thermoplastic resin.

[0036] The adhesive layer 2 may further contain a filler. Examples of the filler include ceramic powder, glass powder, silver powder, copper powder, resin particles, and rubber particles. The content of the filler may be 0 to 30 parts by mass, 1 to 30 parts by mass, or 5 to 15 parts by mass with respect to 100 parts by mass of the content of the thermoplastic resin.

[0037] The total content of the thermoplastic resin, the low-molecular additive, and the coupling agent in the adhesive layer 2, or the total content of the thermoplastic resin, the low-molecular additive, the coupling agent, and the filler may be 90 to 100% by mass based on the mass of the adhesive layer 2.

[0038] From the viewpoint that the curl of the temporary protective film is more easily suppressed, the thickness of the adhesive layer 2 may be 20 μm or less, 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, 9 μm or less, or 8 μm or less. The thickness of the adhesive layer 2 may be 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, 6 μm or more, 7 μm or more, or 8 μm or more.

[0039] The support film 1 may be, for example, a film of at least one polymer selected from the group consisting of aromatic polyimide, aromatic polyamide, aromatic polyamideimide, aromatic polysulfone, aromatic polyethersulfone, polyphenylene sulfide, aromatic polyether ketone, polyarylate, aromatic polyether ether ketone, and polyethylene naphthalate. The support film 1 may be a film of copper, aluminum, stainless steel, or nickel in a film shape. When the support film 1 is a polymer film, its surface may be surface-treated by methods such as alkali treatment, chemical treatment such as silane coupling treatment, physical treatment such as sand mat treatment, plasma treatment, and corona treatment.

[0040] The thickness of the support film 1 may be, for example, 5 to 100 μm, or 5 to 50 μm or less. The thickness T of the support film 1 to the thickness T of the adhesive layer 2 of the ratio T 2 / T 1may be 0.5 or less, 0.3 or less, or 0.2 or less.

[0041] The non - adhesive layer 3 is a resin layer that substantially has no adhesiveness (or pressure - sensitive adhesiveness) to the lead frame at 0 to 270°C. The non - adhesive layer may be a resin layer that is difficult to soften at high temperatures. For example, a resin layer having a high glass transition temperature can function as the non - adhesive layer.

[0042] The resin layer as the non - adhesive layer 3 contains a resin that is a thermoplastic resin, a thermosetting resin (cured product), or a combination thereof. The thermoplastic resin may have an amide group, an ester group, an imide group, an oxy group, or a sulfonyl group. The thermosetting resin may be, for example, an epoxy resin, a phenol resin, or a bismaleimide resin. When combining a thermoplastic resin and a thermosetting resin, the amount of the thermosetting resin may be 5 to 100 parts by mass, or 20 to 70 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

[0043] The non - adhesive layer 3 may contain a filler (such as ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles), a coupling agent, etc. The content of the filler in the non - adhesive layer 3 may be 1 to 30 parts by mass, or 5 to 15 parts by mass with respect to 100 parts by mass of the resin content. The content of the coupling agent may be 1 to 20 parts by mass, or 2 to 15 parts by mass with respect to 100 parts by mass of the resin content.

[0044] The 90 - degree peel strength of the non - adhesive layer 3 against a copper mold may be less than 5 N / m, or 1 N / m or less at 25°C. This peel strength is measured after the non - adhesive layer 3 is pressure - bonded to a copper mold at a temperature of 250°C and a pressure of 8 MPa for 10 seconds.

[0045] The thickness of the non - adhesive layer 3 may be, for example, 10 μm or less, 9 μm or less, 8 μm or less, or 7 μm or less. The thickness of the non - adhesive layer may be, for example, 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, or 6 μm or more. The thickness of the non - adhesive layer is not particularly limited, but may be, for example, 1 to 10 μm, or 1 to 8 μm.

[0046] The temporary protection film can be manufactured by a method including a step of forming an adhesive layer by applying a varnish containing, for example, a thermoplastic resin, an epoxy compound, and a solvent to a support film and removing the solvent from the coating film. The non-adhesive layer can also be formed by a similar method.

[0047] Method for manufacturing a semiconductor package A semiconductor package can be manufactured using the temporary protection film according to the embodiments exemplified above. The manufactured semiconductor package may be, for example, a Non Lead Type Package having a lead frame and a semiconductor element mounted thereon, and a sealing layer that seals the semiconductor element on the semiconductor element side of the lead frame, with the back surface of the lead frame exposed for external connection. Specific examples thereof include QFN (Quad Flat Non-leaded Package) and SON (Small Outline Non-leaded Package).

[0048] FIGS. 3 and 4 are cross-sectional views showing an embodiment of a method for manufacturing a semiconductor package. FIG. 5 is a cross-sectional view showing an embodiment of a semiconductor package obtained by the manufacturing method of FIGS. 3 and 4. Hereinafter, each step will be described with reference to the respective drawings as necessary.

[0049] The method shown in FIGS. 3 and 4 includes the steps of attaching a temporary protection film 10 to the back surface, which is one surface of the lead frame 11 having a die pad 11a and inner leads 11b, with its adhesive layer facing the lead frame 11; mounting a semiconductor element 14 on the surface of the die pad 11a opposite to the temporary protection film 10; providing a wire 12 that connects the semiconductor element 14 and the inner lead 11b; forming a sealing layer 13 that seals the semiconductor element 14 and the wire 12 to obtain a temporarily protected encapsulated molded body 20 having a lead frame 11, a semiconductor element 14, and a sealing layer 13; and peeling the temporary protection film 10 from the encapsulated molded body 20, in this order. The temporarily protected encapsulated molded body is composed of the encapsulated molded body 20 and the temporary protection film 10.

[0050] The step of attaching the temporary protection film 10 to the lead frame 11 may include heating and pressing the temporary protection film 10 disposed on the lead frame 11. The heating temperature may be 150 °C or higher, 180 °C or higher, or 200 °C or higher, and may also be 400 °C or lower. The pressure may be 0.5 to 30 MPa, 1 to 20 MPa, or 3 to 15 MPa. The time for heating and pressing may be 0.1 to 60 seconds, 1 to 30 seconds, or 3 to 20 seconds.

[0051] The lead frame 11 may be formed of, for example, an iron-based alloy such as 42 alloy, copper, or a copper-based alloy. The lead frame 11 may have a molded body formed of copper or a copper-based alloy and a coating layer such as palladium, gold, or silver that coats its surface.

[0052] The semiconductor element 14 is usually adhered to the die pad 11a via an adhesive (e.g., silver paste). After adhering the semiconductor element 14 to the die pad 11a, reflow connection (such as CuClip connection) may be performed under the conditions of a maximum temperature of 250 to 440 °C, or 250 to 400 °C, and a time of 1 to 30 minutes.

[0053] The wire 12 is not particularly limited and may be, for example, a gold wire, a copper wire, or a palladium-coated copper wire. For example, the semiconductor element 14 and the inner lead 11b may be joined to the wire 12 by heating at 200 to 260 °C, or 350 to 260 °C for 3 to 60 minutes and using ultrasonic waves and pressing pressure.

[0054] The sealing layer 13 is formed by sealing and molding using a sealing material. By the sealing and molding, a sealed molded body 20 having a plurality of semiconductor elements 14 and a sealing layer 13 that collectively seals them may be obtained. During the sealing and molding, since the temporary protective film 10 is provided, it is possible to suppress the sealing material from flowing around to the back side of the lead frame 11.

[0055] The temperature (temperature of the sealing material) during the formation of the sealing layer 13 may be 140 to 200 °C, or 160 to 180 °C. The pressure during the formation of the sealing layer may be 6 to 15 MPa, or 7 to 10 MPa. The time for the sealing and molding may be 1 to 5 minutes, or 2 to 3 minutes.

[0056] The formed sealing layer 13 may be heat-cured as necessary. The heating temperature for curing the sealing layer 13 may be 150 to 200 °C, or 160 to 180 °C. The heating time for curing the sealing layer 13 may be 4 to 7 hours, or 5 to 6 hours.

[0057] The sealing material may contain an epoxy resin such as a cresol novolac epoxy resin, a phenol novolac epoxy resin, a biphenyl diepoxy resin, or a naphthol novolac epoxy resin. The sealing material may contain a filler, a flame retardant substance such as a bromine compound, a wax component, and the like.

[0058] After the sealing and molding for forming the sealing layer 13, the temporary protective film 10 is peeled off from the lead frame 11 and the sealing layer 13 of the obtained sealed molded body 20. When curing the sealing layer 13, the temporary protective film 10 may be peeled off at any time before or after the curing of the sealing layer 13.

[0059] The temperature for peeling the temporary protection film 10 from the sealing molded body 20 may be 0 to 250°C, 100 to 200°C, or 150 to 250°C.

[0060] After peeling the temporary protection film 10 from the lead frame 11, if a part of the adhesive layer remains on the lead frame 11 and the sealing layer 13, this may be removed. The remaining adhesive layer may be removed by mechanical brushing or a solvent. The solvent may be, for example, N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, or dimethylformamide.

[0061] When the lead frame includes a plurality of patterns having a die pad and inner leads, if necessary, the sealing molded body 20 may be divided to obtain a plurality of semiconductor packages 100 as shown in FIG. 5 each having one semiconductor element. That is, when the lead frame 11 has a plurality of die pads 11a and semiconductor elements 14 are mounted on each of the plurality of die pads 11a, the manufacturing method according to one embodiment may further include a step of dividing the sealing molded body 20 after peeling the temporary protection film 10 (or 10') from the sealing molded body 20 to obtain a semiconductor package 100 having one die pad 11a and one semiconductor element 14.

[0062] A long temporary protection film may be wound around a winding core, and a semiconductor package may be manufactured while unwinding the temporary protection film from the obtained reel body. In this case, the reel body has a winding core and the temporary protection film according to the above-described embodiment wound around the winding core.

[0063] FIG. 6 is a perspective view showing an embodiment of the reel body. The reel body 30 shown in FIG. 6 includes a core 31, a temporary protection film 10 wound around the core 31, and side plates 32. The widths (lengths in the direction orthogonal to the winding direction) of the core 31 and the temporary protection film 10 may be 0.001 cm or more, 0.005 cm or more, or 0.008 cm or more, and may be 0.03 cm or less. The widths (lengths in the direction orthogonal to the winding direction) of the core 31 and the temporary protection film 10 may be, for example, 0.001 cm or more and 0.03 cm or less, 0.005 cm to 0.03 cm or less, or 0.008 cm or more and 0.03 cm or less.

[0064] The temporary protection film according to the above-described embodiment may be provided as a package in which the reel body is housed in a packaging bag. FIG. 7 shows an embodiment of the package. As shown in FIG. 7, the package 50 includes a reel body 30 and a packaging bag 40 that houses the reel body 30. The reel body 30 is usually individually housed in a packaging bag, but a plurality (for example, 2 to 3) of reel bodies 30 may be housed in one packaging bag 40.

[0065] The packaging bag 40 may be formed of a resin film or may be formed of a composite film that is a resin film having an aluminum layer. Specific examples of the packaging bag 40 include an aluminum-coated plastic bag. Examples of the material of the resin film include plastics such as polyethylene, polyester, vinyl chloride, and polyethylene terephthalate. The reel body 30 may be housed in the packaging bag in a vacuum-packed state, for example. The package 50 is not limited to being vacuum-packed.

[0066] A desiccant may be housed in the packaging bag 40 together with the reel body 30. Examples of the desiccant include silica gel. The package 50 may further have a cushioning material that wraps the packaging bag 40 housing the reel body 30.

[0067] The package 50 may be provided as an object to be packed and stored in a packing box. FIG. 8 shows an embodiment of the object to be packed. As shown in FIG. 8, the object to be packed 70 includes a package 50 and a packing box 60 that houses the package 50. One or more packages 50 are stored in the packing box 60. As the packing box 60, for example, cardboard can be used.

[0068] A semiconductor device manufactured using a temporary protection film according to an embodiment is excellent in terms of high density, small area, thinness, etc., and can be suitably used for electronic devices such as mobile phones, smartphones, personal computers, and tablets.

Example

[0069] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[0070] Study 1 1-1. Preparation of temporary protection film Example 1 270.9 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 chloride were prepared to obtain an aromatic polyether amide imide which is a polycondensate formed therefrom. 100 parts by mass of this aromatic polyether amide imide, 7 parts by mass of sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name: EX-614B, epoxy equivalent: 173 g / eq.), and 3 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: SH6040) were dissolved in N-methylpyrrolidone to obtain a varnish for forming an adhesive layer. The obtained varnish was applied onto one surface of a support film. As the support film, a polyimide film (thickness: 25 μm, manufactured by Ube Industries, Ltd., trade name: Upilex SGA) having a chemically treated surface was used. The coating film on the support film was dried by heating at 100 °C for 10 minutes and at 200 °C for 10 minutes to form an adhesive layer with a thickness of 2 μm, thereby obtaining the temporary protective film of Example 1 having the support film and the adhesive layer.

[0071] Example 2 An adhesive layer-forming varnish and a temporary protective film were obtained in the same manner as in Example 1, except that the amount of sorbitol polyglycidyl ether was changed to 10 parts by mass with respect to 100 parts by mass of the aromatic polyether amide imide.

[0072] Example 3 An adhesive layer-forming varnish and a temporary protective film were obtained in the same manner as in Example 1, except that polyethylene glycol diglycidyl ether (manufactured by Kyoei Chemical Co., Ltd., trade name: Epolite 400E, epoxy equivalent: 264 - 290 g / eq.) was used instead of sorbitol polyglycidyl ether, and the amount thereof was 10 parts by mass with respect to 100 parts by mass of the aromatic polyether amide imide.

[0073] Comparative Example 1 An adhesive layer-forming varnish and a temporary protective film were obtained in the same manner as in Example 1, except that sorbitol polyglycidyl ether was not used.

[0074] 1 - 2. Copper surface analysis before and after heat treatment The temporary protective films of Examples 1 to 3 or Comparative Example 1 were attached to a copper plate A for a lead frame (size: 50 mm × 200 mm, processed from "Product Name: EFTEC64T" manufactured by Shinko Electric Industries Co., Ltd. and Furukawa Electric Co., Ltd., and plasma irradiation treated) at a temperature of 235°C, a pressure of 6 MPa, and a time of 10 seconds with the adhesive layer facing the copper plate. The obtained adhered body was heat-treated in the order of 180°C for 1 hour and 400°C for 2 minutes. Before heat treatment, after heating at 180°C for 1 hour, and after heating at 400°C for 2 minutes, the temporary protective film was peeled off from each adhered body. In the case of the temporary protective films of Example 1 and Comparative Example 1, the exposed copper plate surface was subjected to elemental analysis by energy dispersive X-ray spectroscopy (EDS) to determine the ratio (atomic %) of oxygen atoms. The results are shown in Table 1.

[0075] [Table 1]

[0076] In the cases of Examples 1 to 3, the surface of the copper plate changed color at the time of heating at 180°C for 1 hour, suggesting the formation of copper oxide. However, after further heating at 400°C for 2 minutes, the surface of the copper plate exhibited the color of metallic copper similar to that before heat treatment. In the case of Comparative Example 1, the surface of the copper plate after heating at 400°C for 2 minutes exhibited a color suggesting that it contained a large amount of copper oxide. Such visual observation also suggested that the oxidized copper plate surface was reduced by heating at 400°C.

[0077] 1-3. Peel Strength (1) After Attachment The temporary protective films of Examples 1 to 3 or Comparative Example 1 were attached to copper plate A at a temperature of 235°C, a pressure of 6 MPa, and a time of 10 seconds with the adhesive layer facing copper plate A. Then, the 90-degree peel strength between the adhesive layer and copper plate A at 25°C was measured under the condition of a peeling rate of 300 mm per minute. (2) After Heat Treatment The temporary protective films of Examples 1 to 3 or Comparative Example 1 were attached to Copper Plate A under the conditions of a temperature of 235°C, a pressure of 6 MPa, and a time of 10 seconds, with the adhesive layer facing the Copper Plate A. Subsequently, the Copper Plate A and the temporarily attached protective film were subjected to heat treatment at 180°C for 1 hour and then at 400°C for 2 minutes. After the heat treatment, the 90-degree peel strength between the adhesive layer and the Copper Plate A at 200°C was measured under the condition of a peeling rate of 300 mm per minute.

[0078]

Table 2

[0079] Table 2 shows the evaluation results of the peel strength before and after pasting and heat treatment. The temporary protective film of Example 1 exhibited an appropriate peel strength after pasting and a sufficiently reduced peel strength after heat treatment.

[0080] Study 2 2-1. Preparation of Temporary Protective Film Example 4 An adhesive varnish for forming an adhesive layer and a temporary protective film were obtained in the same manner as in Example 1, except that 7 parts by mass of sorbitol polyglycidyl ether was changed to 10 parts by mass of polyoxyethylene (9) secondary alkyl (carbon number 11 to 15) ether (manufactured by Kao Corporation, trade name: Emulgen 709).

[0081] Example 5 An adhesive varnish for forming an adhesive layer and a temporary protective film were obtained in the same manner as in Example 4, except that the amount of polyoxyethylene (9) secondary alkyl (carbon number 11 to 15) ether was changed to 20 parts by mass with respect to 100 parts by mass of aromatic polyether amide imide.

[0082] 2-2. Copper Surface Analysis and Peel Strength before and after Heat Treatment The temporary protection films of Example 1, 4 or 5 were attached to Copper Plate B (size: 50 mm × 200 mm, processed from "Product Name: EFTEC64T" manufactured by Shinko Electric Industries Co., Ltd., manufactured by Furukawa Electric Co., Ltd., without plasma irradiation treatment) under the conditions of a temperature of 235 °C, a pressure of 6 MPa, and a time of 10 seconds with the adhesive layer facing Copper Plate B. The obtained adhered body was heat-treated in sequence at 180 °C for 1 hour and at 400 °C for 2 minutes. Using the adhered body before heat treatment and after heating at 400 °C for 2 minutes respectively, the 90-degree peel strength between the adhesive layer of the temporary protection film and Copper Plate B at 25 °C or 200 °C was measured under the condition of a peeling rate of 300 mm per minute. In the measurement of the peel strength after heat treatment of Example 4 and 5, generation of residues where a part of the adhesive layer remained on Copper Plate B was observed after peeling. The copper plate surface exposed by peeling the temporary protection film was subjected to elemental analysis by energy dispersive X-ray spectroscopy (EDS) to determine the ratio (atomic %) of oxygen atoms. The results are shown in Table 3.

[0083]

Table 3

Explanation of Signs

[0084] 1... Support film, 2... Adhesive layer, 3... Non-adhesive layer, 10, 10’... Temporary protection film, 11... Lead frame, 11a... Die pad, 11b... Inner lead, 12... Wire, 13... Encapsulation layer, 14... Semiconductor element, 20... Encapsulated molded body, 30... Reel body, 31... Spindle, 32... Side plate, 40... Packaging bag, 50... Package, 60... Packing box, 70... Packaged item, 100... Semiconductor package.

Claims

1. A temporary protection film for semiconductor encapsulation molding, comprising a support film and an adhesive layer provided on one or both surfaces of the support film, and used for temporarily protecting the surface of the lead frame opposite to the semiconductor element during the encapsulation molding for forming an encapsulation layer that encapsulates the semiconductor element mounted on the die pad of the lead frame, wherein the adhesive layer contains a thermoplastic resin and a low molecular weight additive having a molecular weight of less than 1000, the thermoplastic resin contains at least one selected from the group consisting of aromatic polyether amide imide, aromatic polyether imide, aromatic polyether amide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamide imide, aromatic polyether, and aromatic polyester imide, the low molecular weight additive contains an epoxy compound having one or more epoxy groups, when the adhesive layer forms an adherend composed of the copper plate and the temporary protection film for semiconductor encapsulation molding by attaching the temporary protection film for semiconductor encapsulation molding to the surface of the copper plate with the adhesive layer facing the copper plate, and then heating the adherend at 180 °C for 1 hour, the ratio of oxygen atoms on the surface of the copper plate is X1, and then, when the adherend is further heat-treated at 400 °C for 2 minutes, the ratio of oxygen atoms on the surface of the copper plate is X2, the temporary protection film for semiconductor encapsulation molding is configured such that X2 is smaller than X1.

2. The temporary protection film for semiconductor encapsulation molding according to claim 1, wherein X2 is 1.2 atomic % or less when measured by energy dispersive X-ray analysis.

3. The temporary protection film for semiconductor encapsulation molding according to claim 1 or 2, wherein the low molecular weight additive generates a reducing gas by thermal decomposition.

4. The temporary protection film for semiconductor encapsulation molding according to any one of claims 1 to 3, wherein the content of the low molecular weight additive is 5 to 30 parts by mass with respect to 100 parts by mass of the content of the thermoplastic resin.

5. A method for manufacturing a temporary protection film for semiconductor encapsulation molding, comprising a support film and an adhesive layer provided on one or both surfaces of the support film, and used for temporarily protecting the surface of the lead frame opposite to the semiconductor element during the encapsulation molding for forming an encapsulation layer that encapsulates the semiconductor element mounted on the die pad of the lead frame, An adhesive layer composed of 100 parts by mass of a thermoplastic resin and 5 to 20 parts by mass of a low molecular weight additive is attached to the surface of a copper plate to form an attached body composed of the copper plate and the adhesive layer. When the ratio of oxygen atoms on the surface of the copper plate after heating the attached body at 180°C for 1 hour is X1, and then the attached body is subjected to a heat treatment of further heating at 400°C for 2 minutes, and the ratio of oxygen atoms on the surface of the copper plate is X2, select a low molecular weight additive so that X2 is smaller than X1, forming an adhesive layer containing the thermoplastic resin and the selected low molecular weight additive on one or both sides of the support film, including, the thermoplastic resin includes at least one selected from the group consisting of aromatic polyether amide imide, aromatic polyether imide, aromatic polyether amide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamide imide, aromatic polyether, and aromatic polyester imide, the low molecular weight additive includes an epoxy compound having one or more epoxy groups, the method.

6. A lead frame having a die pad, the temporary protection film for semiconductor encapsulation molding according to any one of claims 1 to 4, comprising, the temporary protection film is attached to one surface of the lead frame in such a direction that the adhesive layer of the temporary protection film is in contact with the lead frame, a lead frame with a temporary protection film.

7. A lead frame having a die pad, a semiconductor element mounted on the die pad on one surface side of the lead frame, a sealing layer sealing the semiconductor element, the temporary protection film for semiconductor encapsulation molding according to any one of claims 1 to 4, comprising, the temporary protection film is attached to the surface of the lead frame opposite to the semiconductor element in such a direction that the adhesive layer of the temporary protection film is in contact with the lead frame, a temporarily protected encapsulation molded body.

8. a step of attaching the temporary protection film for semiconductor encapsulation molding according to any one of claims 1 to 4 to one surface of a lead frame having a die pad in such a direction that its adhesive layer is in contact with the lead frame, a step of mounting a semiconductor element on the surface of the die pad opposite to the temporary protection film, Forming a sealing layer for sealing the semiconductor element to obtain a temporarily protected sealed molded body having the lead frame, the semiconductor element, and the sealing layer; Peeling the temporary protection film from the sealed molded body; A method for manufacturing a semiconductor package, comprising these steps in this order.

9. The lead frame has a plurality of the die pads, and the semiconductor element is mounted on each of the plurality of die pads. The method according to claim 8, further comprising the step of dividing the sealed molded body after peeling the temporary protection film from the sealed molded body to obtain a semiconductor device having one of the die pads and the semiconductor element.

Images