Temporary protective film for semiconductor sealing and forming, manufacturing method thereof, lead frame with temporary protective film, sealed and formed body protected temporarily, and method for manufacturing semiconductor package

Abstract

A temporary protective film for semiconductor hermetic forming, which includes a support film and an adhesive layer. The adhesive layer contains a thermoplastic resin and a low-molecular additive with a molecular weight less than 1000. When the temporary protective film for semiconductor hermetic forming 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 protective film for semiconductor hermetic forming, and then the proportion 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, when the proportion of oxygen atoms on the surface of the copper plate after heat treatment of further heating the attached body at 400 °C for 2 minutes is X2, the adhesive layer is configured such that X2 is less than X1.

Description

Technical Field

[0001] The present invention relates to a temporary protective film for semiconductor sealing and forming, a manufacturing method thereof, a lead frame with a temporary protective film, a sealing and forming body protected temporarily, and a method for manufacturing a semiconductor package. Background Art

[0002] In semiconductor packages, there is sometimes a structure in which a sealing layer is formed only on the semiconductor element side of a lead frame and the back surface of the lead frame is exposed (Patent Document 1 and Patent Document 2). In the manufacture of a semiconductor package having this structure, in order to prevent the sealing resin from going around to the back surface of the lead frame during sealing and forming, a temporary protective film is sometimes attached to temporarily protect the back surface of the lead frame. After the sealing layer is formed, the temporary protective film is peeled off from the lead frame.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 5-129473

[0006] Patent Document 2: Japanese Patent Laid-Open No. 10-12773 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] In an assembly process for manufacturing a semiconductor package, for reflow connection or the like, heating is sometimes required at a high temperature of about 400°C. However, if the temporary protective film attached to the lead frame undergoes a thermal history at such a high temperature, the temporary protective film adheres firmly to the lead frame and the sealing layer, and there are sometimes cases where the temporary protective film cannot be peeled off from the lead frame or it is difficult to peel it off cleanly from the lead frame without leaving residues.

[0009] The present invention relates to a temporary protective film for semiconductor sealing and forming, which can be attached to a lead frame with an appropriate bond force and can be easily peeled off after undergoing a thermal history at a high temperature of about 400°C.

[0010] Means for Solving the Technical Problem

[0011] One aspect of the present invention provides a temporary protective film including a support film and an adhesive layer provided on one or both sides of the support film. During the sealing formation of a sealing layer for sealing a semiconductor element mounted on a die pad of a lead frame, the temporary protective film is used to temporarily protect the surface of the lead frame on the side opposite to the semiconductor element. In other words, one aspect of the present invention provides an application of a temporary protective film, which is used to temporarily protect the surface of the lead frame on the side opposite to the semiconductor element during the sealing formation of a sealing layer for sealing a semiconductor element mounted on a die pad of a lead frame. When the temporary protective film for semiconductor sealing formation is attached to the surface of a copper plate with the adhesive layer facing the copper plate to form an attached body composed of the copper plate and the temporary protective film for semiconductor sealing formation, and then the proportion 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 proportion of oxygen atoms on the surface of the copper plate after the attached body is used for heat treatment of further heating at 400 °C for 2 minutes is X2, the adhesive layer is configured such that X2 is less than X1. In other words, when the protective film for semiconductor sealing formation is attached to the surface of a copper plate with the adhesive layer facing the copper plate, and then the attached body composed of the copper plate and the temporary protective film for semiconductor sealing formation is used for heat treatment of heating at 180 °C for 1 hour and then at 400 °C for 2 minutes in sequence, the proportion of oxygen atoms on the surface of the copper plate after heating at 400 °C for 2 minutes is less than the proportion of oxygen atoms on the surface of the copper plate after heating at 180 °C for 1 hour.

[0012] Another aspect of the present invention provides a method for manufacturing a temporary protective film, the temporary protective film including a support film and an adhesive layer provided on one or both sides of the support film. The manufactured temporary protective film is a protective film for semiconductor sealing and forming, and is used to temporarily protect the surface of the lead frame on the side opposite to the semiconductor element during the sealing and forming of a sealing layer for sealing a semiconductor element mounted on a chip pad of the lead frame. The method includes: when an adherend body composed of a copper plate and an adhesive layer formed 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 the copper plate, and the proportion of oxygen atoms on the surface of the copper plate after heating the adherend body at 180°C for 1 hour is X1, and then the proportion of oxygen atoms on the surface of the copper plate after the adherend body is used for a heat treatment of further heating at 400°C for 2 minutes is X2, a step of selecting a low molecular additive so that X2 is less than X1; and a step of forming an adhesive layer containing the thermoplastic resin and the selected low molecular additive on one or both sides of the support film. In other words, the method includes: when the adherend body 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 the copper plate is used for heat treatments of heating at 180°C for 1 hour and heating at 400°C for 2 minutes in sequence, a step of selecting a low molecular additive such that the proportion of oxygen atoms on the surface of the copper plate after heating at 400°C for 2 minutes is less than the proportion of oxygen atoms on the surface of the copper plate after heating at 180°C for 1 hour; and a step of forming an adhesive layer containing the thermoplastic resin and the selected low molecular additive on one or both sides of the support film.

[0013] Another aspect of the present invention provides a lead frame with a temporary protective film, which includes: a lead frame having a chip pad; and the above-mentioned temporary protective film for semiconductor sealing and forming. The temporary protective film is attached to one surface of the lead frame with the adhesive layer of the temporary protective film facing the lead frame.

[0014] Another aspect of the present invention provides a temporarily protected sealed formed body, which includes: a lead frame having a chip pad; a semiconductor element mounted on the chip pad on one side of the lead frame; a sealing layer for sealing the semiconductor element; and the above-mentioned temporary protective film for semiconductor sealing and forming. The temporary protective film is attached to the surface of the lead frame on the side opposite to the semiconductor element with the adhesive layer of the temporary protective film facing the lead frame.

[0015] Another aspect of the present invention relates to a method for manufacturing a semiconductor package, which sequentially includes: a step of attaching the temporary protective film for semiconductor sealing and forming on one surface of a lead frame having chip pads with the adhesive layer thereof facing the lead frame; a step of mounting a semiconductor element on the surface of the chip pad opposite to the temporary protective film; a step of forming a sealing layer for sealing the semiconductor element to obtain a temporarily protected sealed and formed body having the lead frame, the semiconductor element, and the sealing layer; and a step of peeling the temporary protective film from the sealed and formed body.

[0016] Advantages of the Invention

[0017] According to one aspect of the present invention, there is provided a temporary protective film for semiconductor sealing and forming, which can be attached to a lead frame with an appropriate adhesive force and can be easily peeled off after undergoing a thermal process at a high temperature of about 400°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view showing an embodiment of the temporary protective film.

[0019] Figure 2 It is a cross-sectional view showing an embodiment of the temporary protective film.

[0020] Figure 3 It is a cross-sectional view illustrating an embodiment of a method for manufacturing a semiconductor device.

[0021] Figure 4 It is a cross-sectional view illustrating an embodiment of a method for manufacturing a semiconductor device.

[0022] Figure 5 It is a cross-sectional view showing an embodiment of a semiconductor device.

[0023] Figure 6 It is a perspective view showing an embodiment of a reel body.

[0024] Figure 7 It is a front view showing an embodiment of a package.

[0025] Figure 8 It is a front view showing an embodiment of a bundled object. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention is not limited to the several embodiments exemplified below. The upper and lower limit values of the numerical ranges described in this specification can be arbitrarily combined. The numerical values described in the examples can also be used as the upper or lower limit values of the numerical ranges.

[0027] Temporary Protective Film

[0028] Figure 1It is a cross-sectional view of a temporary protective film according to an embodiment. Figure 1 The shown temporary protective film 10 is composed of a support film 1 and an adhesive layer 2 provided on one side of the support film 1. The adhesive layer may also be formed on both sides of the support film 1. Figure 2 It is also a cross-sectional view of a temporary protective film according to an embodiment. Figure 2 The temporary protective film 10' 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. During the sealing process of forming a sealing layer, by attaching to the back surface of the lead frame (the surface opposite to the surface on which the semiconductor element is mounted), these temporary protective films can be used as temporary protective films for semiconductor sealing of the lead frame during the sealing process, and the sealing layer seals the semiconductor element on the chip pad mounted on the lead frame.

[0029] The adhesive layer 2 contains a thermoplastic resin and a low molecular weight additive.

[0030] The thermoplastic resin may contain 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. From the viewpoints of heat resistance and adhesiveness, the thermoplastic resin may be at least one selected from the group consisting of aromatic polyether amide imide, aromatic polyether imide, and aromatic polyether amide, or may be aromatic polyether amide imide.

[0031] The aromatic polyether amide imide may be a condensate formed from an acid component containing an aromatic tricarboxylic acid or its reactive derivative 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 oxygen group (-O-) bonding the aromatic groups to each other. The aromatic polyether imide may be a condensate formed from an acid component containing an aromatic tetracarboxylic acid or its reactive derivative 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 oxygen bonding the aromatic groups to each other. The aromatic polyether amide may be a condensate formed from an acid component containing an aromatic dicarboxylic acid or its reactive derivative 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 oxygen bonding the aromatic groups to each other. The reactive derivative of the carboxylic acid may be, for example, an acid anhydride or an acyl chloride.

[0032] Aromatic polyether amide imides and aromatic polyamide imides may also contain structural units derived from trimellitic acid or its reactive derivatives. Aromatic polyimides and aromatic polyether imides may also contain pyromellitic acid, polynuclear aromatic tetracarboxylic acids or structural units derived from these reactive derivatives. Examples of polynuclear aromatic tetracarboxylic acids include bisphenol A bis-trimellitate and oxydiphthalic acid. Aromatic polyamides may also contain terephthalic acid, isophthalic acid or structural units derived from these reactive derivatives.

[0033] Aromatic polyether amide imides, aromatic polyether imides and aromatic polyether amides may also contain structural units derived from aromatic diamines having an oxy group selected from, for example, 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 also further contain structural units derived from other diamines selected from aromatic diamines without an oxy group (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).

[0034] 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 also be 60 to 89 mol% or 68 to 82 mol%, the proportion of the structural unit derived from the siloxane diamine may also be 1 to 10 mol% or 3 to 7 mol%, and the proportion of the structural unit derived from the α,ω-diaminoalkane may also 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 also be 90 to 99 mol% or 93 to 97 mol%, and the proportion of the structural unit derived from the siloxane diamine may also 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 also be 40 to 70 mol% or 45 to 60 mol%, and the proportion of the structural unit derived from the aromatic diamine not having an oxy group may also be 30 to 60 mol% or 40 to 55 mol%.

[0035] The low molecular weight additive is a compound with a molecular weight less than 1000 and can be selected according to 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 used for a specified 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 used for a heat treatment of heating at 180°C for 1 hour and then heating at 400°C for 2 minutes in an atmospheric environment, a low molecular weight additive is selected such that the proportion X2 of oxygen atoms on the surface of the copper plate after heating at 400°C for 2 minutes is less than the proportion X1 of oxygen atoms on the surface of the copper plate after heating at 180°C for 1 hour. The surface of the copper plate in contact with the adhesive layer is oxidized by heating at 180°C for 1 hour to form a surface containing a large amount of oxygen atoms from copper oxide. However, depending on the type of low molecular weight additive contained in the adhesive layer, the proportion of oxygen atoms on the surface of the copper plate decreases after heating at 400°C for 2 minutes. According to the inventor's opinion, by adding a low molecular weight additive that exhibits such a decrease in the proportion of oxygen atoms to the adhesive, the peelability from the lead frame after heat treatment can be improved. The decrease in the proportion of oxygen atoms indicates that at least a part of the copper oxide is reduced by a reducing gas generated by the decomposition of the low molecular weight additive. For example, it is speculated 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 the aggregation and breakdown of a part of the thin metallic copper formed by the reduction of the copper oxide. The reducing gas may also be hydrogen, carbon monoxide, or hydrocarbon gases such as methane, propane, and butane. When the low molecular weight additive generates a reducing gas by thermal decomposition, 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 to measure X1 and X2 may or may not be subjected to plasma irradiation treatment.

[0036] The proportion of oxygen atoms on the surface of the copper plate, for example, can be determined by energy-dispersive X-ray analysis (EDS) or X-ray photoelectron spectroscopy (XPS) of the surface that can be exposed by peeling off the adhesive layer. At the moment after heat treatment of heating at 180 °C for 1 hour and then heating at 400 °C for 2 minutes in sequence, the proportion of oxygen atoms determined by the EDS-based method can also 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 moment before heat treatment, the proportion of oxygen atoms determined by the EDS-based method can also 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. After heating at 180 °C for 1 hour and before heating at 400 °C for 2 minutes, the proportion of oxygen atoms determined by the EDS-based method can also 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 %.

[0037] The low-molecular additive can also 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. As a specific example of such an epoxy compound, sorbitol polyglycidyl ether and polyethylene glycol diglycidyl ether can be cited.

[0038] Sorbitol polyglycidyl ether is a compound having a residue of sorbitol and two or more glycidyl ether groups bonded thereto, and can also be a mixture of two or more components having different numbers of glycidyl ether groups. The epoxy equivalent of sorbitol polyglycidyl ether can also be, for example, 150 to 200 g / eq.

[0039] Polyethylene glycol monoalkyl ether and polyethylene glycol dialkyl ether are ether compounds formed from one molecule of polyethylene glycol and one molecule or two molecules of alkyl alcohol. The number of carbon atoms of the alkyl alcohol can also be 6 to 24. The alkyl alcohol can also be a secondary alcohol. Examples of polyethylene glycol monoalkyl ether and polyethylene glycol dialkyl ether include polyoxyethylene (9) secondary alkyl (11 to 15 carbon atoms) ether.

[0040] From the viewpoint of peelability from the lead frame after undergoing a heat history at 400 °C, the content of the low molecular weight additive may also 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 viewpoint, the content of sorbitol polyglycidyl ether may also be 5 to 20 parts by mass or 5 to 12 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

[0041] 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):

[0042]

[0043] In formula (I), R 1 , R 2 and R 3 each independently represent an alkoxy group having 1 to 3 carbon atoms, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and X represents a group containing a reactive functional group.

[0044] Examples of the alkoxy group having 1 to 3 carbon atoms as R 1 , R 2 or R 3 include methoxy, ethoxy, and propoxy. Examples of the alkyl group having 1 to 6 carbon atoms as R 1 , R 2 or R 3 include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl. Examples of the aryl group having 6 to 12 carbon atoms as R 1 , R 2 or R 3 include phenyl, tolyl, xylyl, and naphthyl.

[0045] The reactive functional group that X has may, for example, also be an amino group, an isocyanate group, an amide group, or an epoxy group. X may also be a group represented by the following formula (IIa), (IIb), (IIc), (IId), or (IIe):

[0046]

[0047] In these formulas, R 4 , R 5 and R 6 represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a hydrogen atom. * represents the bonding site to the carbon atom. R 4 , R 5 and R 6It may also be an alkyl group having 1 to 6 carbon atoms selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl and hexyl, or an aryl group having 6 to 12 carbon atoms selected from phenyl, tolyl, xylyl and naphthyl.

[0048] Examples of the silane coupling agent in which X is a group represented by the 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.

[0049] Examples of the silane coupling agent in which X is a group represented by (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.

[0050] Examples of the silane coupling agent in which X is a group represented by the formula (IIc) include 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropylmethyldiethoxysilane.

[0051] Examples of the silane coupling agent in which X is a group represented by (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.

[0052] Examples of the silane coupling agent in which X is a group represented by (IIe) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane.

[0053] The content of the coupling agent may also be 1 to 40 parts by mass relative 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 further improved. When the content of the coupling agent is 40% by mass or less, gelation, viscosity reduction, etc. of the varnish used for forming the adhesive layer 2 are less likely to occur, and a temporary protective film can be more easily manufactured. From the same viewpoint, the content of the coupling agent may also 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 relative to 100 parts by mass of the content of the thermoplastic resin.

[0054] 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 also be 0 to 30 parts by mass, 1 to 30 parts by mass, or 5 to 15 parts by mass relative to 100 parts by mass of the content of the thermoplastic resin.

[0055] The total content of the thermoplastic resin, low molecular weight additive, and coupling agent or the total content of the thermoplastic resin, low molecular weight additive, coupling agent, and filler in the adhesive layer 2 may also be 90 to 100% by mass based on the mass of the adhesive layer 2.

[0056] From the viewpoint of more easily suppressing the curling of the temporary protective film, the thickness of the adhesive layer 2 can 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 can 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.

[0057] The support film 1 can be, for example, at least one polymer film 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 can also be a film-like copper, aluminum, stainless steel, or nickel. When the support film 1 is a polymer film, its surface can also be surface-treated by chemical treatments such as alkali treatment and silane coupling treatment, physical treatments such as sand pad treatment, and methods such as plasma treatment and corona treatment.

[0058] The thickness of the support film 1 can be, for example, 5 to 100 μm or 5 to 50 μm or less. The ratio T2 / T1 of the thickness T2 of the adhesive layer to the thickness T1 of the support film can be 0.5 or less, 0.3 or less, or 0.2 or less.

[0059] The non-adhesive layer 3 is a resin layer that substantially does not have adhesiveness (or pressure-sensitive adhesiveness) to the lead frame at 0 to 270°C. The non-adhesive layer can be a resin layer that is not easily softened at high temperatures. For example, a resin layer having a high glass transition temperature can function as the non-adhesive layer.

[0060] The resin layer of the non-adhesive layer 3 contains a thermoplastic resin, a thermosetting resin (cured product), or a resin as a combination thereof. The thermoplastic resin can also have an amide group, an ester group, an imide group, an oxy group, or a sulfonyl group. The thermosetting resin can be, for example, an epoxy resin, a phenolic resin, or a bismaleimide resin. When combining a thermoplastic resin and a thermosetting resin, the amount of the thermosetting resin can also 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.

[0061] The non-adhesive layer 3 can also contain fillers (such as ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles), coupling agents, etc. The content of the filler in the non-adhesive layer 3 can also 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 can also 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.

[0062] The peel strength of the non-adhesive layer 3 with respect to the brass mold at 90 degrees can be less than 5 N / m or 1 N / m or less at 25°C. The peel strength is measured after pressing the non-adhesive layer 3 onto the brass mold at a temperature of 250°C and a pressure of 8 MPa for 10 seconds.

[0063] The thickness of the non-adhesive layer 3 can 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 can 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 and can be, for example, 1 to 10 μm or 1 to 8 μm.

[0064] The temporary protective film can be manufactured, for example, by a method including the following steps: coating a varnish containing a thermoplastic resin, an epoxy compound, and a solvent on a support film and removing the solvent from the coating film to form an adhesive layer. The non-adhesive layer can also be formed by the same method.

[0065] Method for manufacturing a semiconductor package

[0066] A semiconductor package can be manufactured using the temporary protective film according to the above-exemplified embodiments. The manufactured semiconductor package can be, for example, a non-lead type package in which a lead frame, a semiconductor element mounted on the lead frame, and a sealing layer for sealing the semiconductor element on the semiconductor element side of the lead frame are provided, and the back surface of the lead frame is exposed for external connection. As other specific examples, QFN (Quad Flat Non-leaded Package) and SON (Small Outline Non-leaded Package) can be cited.

[0067] Figure 3 and Figure 4 is a cross-sectional view showing an embodiment of a method for manufacturing a semiconductor package. Figure 5 is shown by Figure 3 and Figure 4 A cross-sectional view of an embodiment of a semiconductor package obtained by the manufacturing method. Hereinafter, each process will be described with reference to the respective drawings as needed.

[0068] Figure 3 and Figure 4The method shown successively includes: a step of attaching the temporary protective film 10 to the back surface, which is one surface of the lead frame 11 having the chip pad 11a and the inner lead 11b, with the adhesive layer thereof facing the lead frame 11; a step of mounting the semiconductor element 14 on the surface of the chip pad 11a opposite to the temporary protective film 10; a step of providing a wire 12 connecting the semiconductor element 14 and the inner lead 11b; a step of forming a sealing layer 13 for sealing the semiconductor element 14 and the wire 12 to obtain a temporarily protected sealed molded body 20 having the lead frame 11, the semiconductor element 14, and the sealing layer 13; and a step of peeling the temporary protective film 10 from the sealed molded body 20. The temporarily protected sealed molded body is composed of the sealed molded body 20 and the temporary protective film 10.

[0069] The step of attaching the temporary protective film 10 to the lead frame 11 may also include steps of heating and pressing the temporary protective 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 also be 0.5 to 30 MPa, 1 to 20 MPa, or 3 to 15 MPa. The heating and pressing time may also be 0.1 to 60 seconds, 1 to 30 seconds, or 3 to 20 seconds.

[0070] The lead frame 11 may also be formed of, for example, an iron-based alloy such as 42 alloy, copper, or a copper-based alloy. The lead frame 11 may also have a molded body formed of copper or a copper-based alloy and a coating layer such as palladium, gold, or silver coating its surface.

[0071] The semiconductor element 14 is generally bonded to the chip pad 11a via an adhesive (for example, silver paste). After bonding the semiconductor element 14 to the chip pad 11a, reflow soldering connection (such as CuClip (copper strip) connection, etc.) may also be performed under the conditions of a temperature of 250 to 440°C or 250 to 400°C at the maximum and a time of 1 to 30 minutes.

[0072] The wire 12 is not particularly limited. For example, it may be a gold wire, a copper wire, or a palladium-coated copper wire. For example, it may also be heated at 200 to 260°C or 350 to 260°C for 3 to 60 minutes, and the semiconductor element 14 and the inner lead 11b may be joined to the wire 12 using ultrasonic waves and pressing pressure.

[0073] The sealing layer 13 is formed by sealing molding using a sealing material. Through the sealing molding, a sealed molded body 20 having a plurality of semiconductor elements 14 and a sealing layer 13 for sealing them together may also be obtained. During the sealing molding, by providing the temporary protective film 10, it is possible to suppress the sealing material from migrating to the back side of the lead frame 11.

[0074] The temperature during the formation of the sealing layer 13 (temperature of the sealing material) may also be 140 to 200 °C or 160 to 180 °C. The pressure during the formation of the sealing layer may also be 6 to 15 MPa or 7 to 10 MPa. The time for sealing formation may also be 1 to 5 minutes or 2 to 3 minutes.

[0075] The formed sealing layer 13 may be heated and cured as needed. The heating temperature for the curing of the sealing layer 13 may also be 150 to 200 °C or 160 to 180 °C. The heating time for the curing of the sealing layer 13 may also be 4 to 7 hours or 5 to 6 hours.

[0076] The sealing material may also contain epoxy resins such as cresol novolac epoxy resin, phenol novolac epoxy resin, biphenyl diepoxy resin, naphthol novolac epoxy resin, etc. The sealing material may also contain flame retardant substances such as fillers and bromine compounds, and wax components.

[0077] After the sealing formation of 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 sealing formed body 20. In the case of curing the sealing layer 13, the temporary protective film 10 may be peeled off at any time before or after curing the sealing layer 13.

[0078] The temperature for peeling the temporary protective film 10 from the sealing formed body 20 may also be 0 to 250 °C, 100 to 200 °C or 150 to 250 °C.

[0079] After peeling the temporary protective film 10 from the lead frame 11, in the case where a part of the adhesive layer remains on the lead frame 11 and the sealing layer 13, it 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.

[0080] In the case where the lead frame includes a plurality of patterns having chip pads and inner leads, as needed, the sealing formed body 20 can be divided to obtain a plurality of semiconductor packages 100 each having 1 semiconductor element. Figure 5 That is, in the case where 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 may further include the following steps: after peeling the temporary protective film 10 (or 10') from the sealing formed body 20, dividing the sealing formed body 20 to obtain a semiconductor package 100 having 1 chip pad 11a and a semiconductor element 14.

[0081] The long strip of temporary protective film can also be wound around a core, and while the temporary protective film is unwound from the obtained reel body, a semiconductor package is manufactured. At this time, the reel body has a core and the temporary protective film according to the above-described embodiment wound around the core.

[0082] Figure 6 It is a perspective view showing an embodiment of the reel body. Figure 6 The shown reel body 30 includes a core 31, a temporary protective film 10 wound around the core 31, and side plates 32. The widths of the core 31 and the temporary protective film 10 (the lengths in the direction orthogonal to the winding direction) can be 0.001 cm or more, 0.005 cm or more, or 0.008 cm or more, and can be 0.03 cm or less. The widths of the core 31 and the temporary protective film 10 (the lengths in the direction orthogonal to the winding direction) can be, for example, 0.001 cm or more and 0.03 cm or less, 0.005 cm or more and 0.03 cm or less, or 0.008 cm or more and 0.03 cm or less.

[0083] The temporary protective film according to the above-described embodiment can also be provided as a package body in which the reel body is stored in a packaging bag. Figure 7 It shows an embodiment of the package body. As Figure 7 shown, the package body 50 includes a reel body 30 and a packaging bag 40 that houses the reel body 30. The reel body 30 is usually individually stored in the packaging bag, but multiple (for example, 2 to 3) reel bodies 30 can also be stored in one packaging bag 40.

[0084] The packaging bag 40 can be formed of a resin film or a composite film that is a resin film having an aluminum layer. As a specific example of the packaging bag 40, a plastic bag coated with aluminum can be cited. As raw materials for the resin film, plastics such as polyethylene, polyester, vinyl chloride, and polyethylene terephthalate can be cited. The reel body 30 can also be stored in the packaging bag in a vacuum-packed state, for example. The package body 50 is not limited to a vacuum-packed package body.

[0085] In the packaging bag 40, a desiccant can also be stored together with the reel body 30. As the desiccant, for example, silica gel can be cited. The package body 50 can further have a cushioning material that wraps the packaging bag 40 that houses the reel body 30.

[0086] The package body 50 can also be provided as a package stored in a packing box. Figure 8 It shows an embodiment of the package. As Figure 8 shown, the package 70 includes a package body 50 and a packing box 60 that houses the package body 50. One or more package bodies 50 are stored in the packing box 60. As the packing box 60, for example, a corrugated cardboard box can be used.

[0087] A semiconductor device manufactured using the temporary protective film according to an embodiment is excellent in terms of high density, small area, thin thickness, etc., and can be preferably used in electronic devices such as mobile phones, smartphones, personal computers, and tablet computers, for example.

[0088] Examples

[0089] Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

[0090] Study 1

[0091] 1-1. Production of temporary protective film

[0092] Example 1

[0093] An aromatic polyetheramideimide, which is a condensate formed from 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, was prepared. 100 parts by mass of this aromatic polyetheramideimide, 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 Dow Corning Toray Silicone Co., Ltd., trade name: SH6040) were dissolved in N-methylpyrrolidone to obtain a varnish for forming an adhesive layer.

[0094] The obtained varnish was coated on 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, and the temporary protective film of Example 1 having a support film and an adhesive layer was obtained.

[0095] Example 2

[0096] The amount of sorbitol polyglycidyl ether was changed to 10 parts by mass with respect to 100 parts by mass of the aromatic polyetheramideimide, and otherwise, in the same manner as in Example 1, a varnish for forming an adhesive layer and a temporary protective film were obtained.

[0097] Example 3

[0098] Instead of sorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether (manufactured by KYOEISHA CHEMICAL Co., LTD., trade name: EPOLIGHT 400E, epoxy equivalent: 264 to 290 g / eq.) was used. With respect to 100 parts by mass of the aromatic polyether amide imide, the amount thereof was set to 10 parts by mass. Except for this, in the same manner as in Example 1, a varnish for forming an adhesive layer and a temporary protective film were obtained.

[0099] Comparative Example 1

[0100] Sorbitol polyglycidyl ether was not used. Except for this, in the same manner as in Example 1, a varnish for forming an adhesive layer and a temporary protective film were obtained.

[0101] 1-2. Analysis of the copper surface before and after heat treatment

[0102] Under the conditions of a temperature of 235 °C, a pressure of 6 MPa, and a time of 10 seconds, the temporary protective films of Example 1 to Example 3 or Comparative Example 1 were attached to a copper plate A for a lead frame (size: 50 mm × 200 mm, manufactured by SHINKO ELECTRIC INDUSTRIES CO., LTD., a copper plate processed from "trade name: EFTEC64T" manufactured by FURU KAWA ELECTRIC CO., LTD., and plasma irradiation treatment was completed) with the adhesive layer facing the copper plate. The obtained adherends were heat-treated at 180 °C for 1 hour and then at 400 °C for 2 minutes in sequence. Before the heat treatment, after heating at 180 °C for 1 hour and after heating at 400 °C for 2 minutes, the temporary protective films were peeled off from each adherend. For the temporary protective films of Example 1 and Comparative Example 1, elemental analysis was performed on the exposed copper plate surface by energy dispersive X-ray analysis (EDS), and the proportion (atomic %) of oxygen atoms was thereby determined. The results are shown in Table 1.

[0103] [Table 1]

[0104]

[0105] In the cases of Example 1 to 3, at the moment after heating at 180 °C for 1 hour, the surface of the copper plate changed color, indicating the formation of copper oxide. However, after further heating at 400 °C for 2 minutes, the surface of the copper plate showed the same color as that of metallic copper before the heat treatment. In the case of Comparative Example 1, after heating at 400 °C for 2 minutes, the surface of the copper plate showed a color indicating the presence of a large amount of copper oxide. It can also be known from such visual observation that the oxidized copper plate surface was reduced by heating at 400 °C.

[0106] 1-3. Peel strength

[0107] (1) After attachment

[0108] Under the conditions of a temperature of 235 °C, a pressure of 6 MPa, and a time of 10 seconds, the temporary protective films of Examples 1 to 3 or Comparative Example 1 were attached to copper plate A with the adhesive layer facing the 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 peel speed of 300 mm per minute.

[0109] (2) After heat treatment

[0110] Under the conditions of a temperature of 235 °C, a pressure of 6 MPa, and a time of 10 seconds, the temporary protective films of Examples 1 to 3 or Comparative Example 1 were attached to copper plate A with the adhesive layer facing the copper plate A. Then, copper plate A and the temporary protective film attached thereto were used for heat treatment at 180 °C for 1 hour and then at 400 °C for 2 minutes. After heat treatment, the 90-degree peel strength between the adhesive layer and copper plate A at 200 °C was measured under the condition of a peel speed of 300 mm per minute.

[0111] [Table 2]

[0112]

[0113] Table 2 shows the evaluation results of the peel strength after attachment and after heat treatment. The temporary protective film of Example 1 exhibited a moderate peel strength after attachment and a sufficiently reduced peel strength after heat treatment.

[0114] Study 2

[0115] 2-1. Preparation of temporary protective film

[0116] Example 4

[0117] 7 parts by mass of sorbitol polyglycidyl ether was changed to 10 parts by mass of polyoxyethylene (9) secondary alkyl (carbon atoms 11 to 15) ether (manufactured by Kao Corporation, trade name: EMULGEN 709). Otherwise, in the same manner as in Example 1, a varnish for forming an adhesive layer and a temporary protective film were obtained.

[0118] Example 5

[0119] With respect to 100 parts by mass of aromatic polyether amide imide, the amount of polyoxyethylene (9) secondary alkyl (carbon atoms 11 to 15) ether was changed to 20 parts by mass. Otherwise, in the same manner as in Example 4, a varnish for forming an adhesive layer and a temporary protective film were obtained.

[0120] 2-2. Copper surface analysis and peel strength before and after heat treatment

[0121] Under the conditions of a temperature of 235°C, a pressure of 6 MPa, and a time of 10 seconds, the temporary protective film of Example 1, Example 4, or Example 5 was attached to copper plate B (size: 50 mm × 200 mm, manufactured by SHINKO ELECTRIC INDUSTRIES CO., LTD., a copper plate processed from "Product Name: EFTEC64T" manufactured by FURUKAWA ELECTRIC CO., LTD., without plasma irradiation treatment) with the adhesive layer facing the copper plate B. The obtained adherend was heat-treated at 180°C for 1 hour and then at 400°C for 2 minutes in sequence. Using each adherend before heat treatment and after heating at 400°C for 2 minutes, the 90-degree peel strength between the adhesive layer of the temporary protective film and copper plate B was measured at 25°C or 200°C under the condition of a peel speed of 300 mm per minute. In the peel strength measurement after heat treatment of Example 4 and Example 5, it was confirmed that there were residues of a part of the adhesive layer remaining on copper plate B after peeling.

[0122] Elemental analysis was performed on the surface of the copper plate exposed by peeling the temporary protective film using energy-dispersive X-ray analysis (EDS), and the proportion (atomic %) of oxygen atoms was determined. The results are shown in Table 3.

[0123] [Table 3]

[0124]

[0125] Symbol Explanation

[0126] 1 - Support film, 2 - Adhesive layer, 3 - Non-adhesive layer, 10, 10’ - Temporary protective film, 11 - Lead frame, 11a - Chip pad, 11b - Inner lead, 12 - Conductive wire, 13 - Sealing layer, 14 - Semiconductor element, 20 - Sealed molded body, 30 - Reel body, 31 - Core, 32 - Side plate, 40 - Packaging bag, 50 - Package, 60 - Packing box, 70 - Packing material, 100 - Semiconductor package.

Claims

1. A temporary protective film for semiconductor hermetic molding, which has a support film and an adhesive layer provided on one or both sides of the support film, and during the hermetic molding of forming a hermetic layer for hermetically sealing a semiconductor element on a chip pad mounted on a lead frame, the temporary protective film for semiconductor hermetic molding is used to temporarily protect the surface of the lead frame on the side opposite to the semiconductor element. The adhesive layer contains a thermoplastic resin and a low-molecular additive having a molecular weight of less than 1000. The thermoplastic resin contains an aromatic polyether amide imide. The low-molecular additive is sorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether, or a combination thereof. The content of the low-molecular additive is 5 to 30 parts by mass relative to 100 parts by mass of the content of the thermoplastic resin. When the temporary protective film for semiconductor hermetic 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 protective film for semiconductor hermetic molding, and then the attached body is heated at 180 °C for 1 hour, the proportion of oxygen atoms on the surface of the copper plate is X1, and then, when the attached body is used for a heat treatment of further heating at 400 °C for 2 minutes, the proportion of oxygen atoms on the surface of the copper plate is X2, the adhesive layer is configured such that X2 is less than X1.

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

3. The temporary protective film for semiconductor hermetic molding according to claim 1 or 2, wherein The low-molecular additive generates a reducing gas by thermal decomposition.

4. A method for manufacturing a temporary protective film for semiconductor hermetic molding, the temporary protective film for semiconductor hermetic molding has a support film and an adhesive layer provided on one or both sides of the support film, and during the hermetic molding of forming a hermetic layer for hermetically sealing a semiconductor element on a chip pad mounted on a lead frame, the temporary protective film for semiconductor hermetic molding is used to temporarily protect the surface of the lead frame on the side opposite to the semiconductor element. The method for manufacturing a temporary protective film for semiconductor hermetic molding includes: When 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 is attached to the surface of a copper plate to form an attached body composed of the copper plate and the adhesive layer, and the proportion 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, when the attached body is used for a heat treatment of further heating at 400 °C for 2 minutes, the proportion of oxygen atoms on the surface of the copper plate is X2, a step of selecting a low-molecular additive such that X2 is less than X1; and A step of forming an adhesive layer containing the thermoplastic resin and the selected low-molecular additive on one or both sides of the support film, wherein the thermoplastic resin contains an aromatic polyether amide imide. The low-molecular additive is sorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether, or a combination thereof.

5. A lead frame with a temporary protective film, comprising: A lead frame having chip pads; and The temporary protective film for semiconductor hermetic molding according to 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 facing the lead frame.

6. A temporarily protected hermetic molded body, comprising: A lead frame having chip pads; A semiconductor element mounted on the chip pads on one side of the lead frame; A sealing layer for sealing the semiconductor element; and The temporary protective film for semiconductor hermetic molding according to any one of claims 1 to 3, The temporary protective film is attached to the surface of the lead frame on the side opposite to the semiconductor element with the adhesive layer of the temporary protective film facing the lead frame.

7. A method of manufacturing a semiconductor package, successively including: A step of attaching the temporary protective film for semiconductor hermetic molding according to any one of claims 1 to 3 to one surface of a lead frame having chip pads with the adhesive layer of the temporary protective film facing the lead frame; A step of mounting a semiconductor element on the surface of the chip pad opposite to the temporary protective film; A step of forming a sealing layer for sealing the semiconductor element to obtain a temporarily protected hermetic molded body having the lead frame, the semiconductor element, and the sealing layer; and A step of peeling the temporary protective film from the hermetic molded body.

8. The method according to claim 7, wherein The lead frame has a plurality of the chip pads, and the semiconductor element is mounted on each of the plurality of chip pads, The method further includes a step of dividing the hermetic molded body after peeling the temporary protective film from the hermetic molded body to obtain a semiconductor device having one of the chip pads and the semiconductor element.

Images