JP7447647B2 - Temporary protective film for semiconductor encapsulation molding and its manufacturing method, lead frame with temporary protective film, encapsulating molded body, and method for manufacturing a semiconductor package - Google Patents

Description

The present invention relates to a temporary protective film for semiconductor encapsulation, a method for manufacturing the same, a lead frame with a temporary protective film, a molded encapsulation, and a method for manufacturing a semiconductor package.

In semiconductor packages, a structure is sometimes adopted 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 Documents 1 and 2). In manufacturing a semiconductor package having this structure, the back side of the lead frame is sometimes temporarily protected by pasting a temporary protective film in order to prevent the sealing resin from getting around to the back side of the lead frame during sealing molding. The temporary protective film is peeled off from the lead frame after the sealing layer is formed.

Japanese Patent Application Publication No. 5-129473 Japanese Patent Application Publication No. 10-12773

Assembly processes for manufacturing semiconductor packages sometimes require heating at high temperatures of up to about 400° C. for reflow connections and the like. However, when the temporary protective film attached to the lead frame is subjected to heat history at such high temperatures, the temporary protective film, lead frame, and sealing layer become firmly adhered, and the temporary protective film is peeled off from the lead frame. In some cases, the lead frame cannot be removed or it is difficult to remove the lead frame cleanly without leaving any residue.

The present invention provides a temporary protective film for semiconductor encapsulation molding that can be attached to a lead frame with appropriate adhesive strength and can be easily peeled off after being subjected to high temperature thermal history of about 400°C. I will provide a.

One aspect of the present invention provides a temporary protective film that includes a support film and an adhesive layer provided on one or both sides of the support film. This temporary protective film is used to temporarily protect the surface of the lead frame opposite to the semiconductor element during sealing molding to form a sealing layer for sealing the semiconductor element mounted on the die pad of the lead frame. This is a temporary protective film used for semiconductor encapsulation molding. The adhesive layer includes a thermoplastic resin and a low molecular weight additive having a molecular weight of less than 1000. When a film consisting of 100 parts by mass of the thermoplastic resin and 10 parts by mass of the low-molecular additive is heated from 25°C to 420°C, the weight loss rate is 10% or more based on the weight at 25°C.

Another aspect of the present invention provides a method for manufacturing a 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 temporarily protects the surface of the lead frame opposite to the semiconductor element during sealing molding to form a sealing layer that seals the semiconductor element mounted on the die pad of the lead frame. This is a temporary protective film for semiconductor encapsulation molding. In this method, when a film consisting of 100 parts by mass of a thermoplastic resin and 10 parts by mass of a low-molecular additive is heated from 25°C to 420°C, the weight loss rate is 10% or more based on the weight at 25°C. and forming an adhesive layer containing the thermoplastic resin and the selected low molecule additive on one or both sides of the support film.

Yet another aspect of the present invention provides a lead frame with a temporary protective film, which includes a lead frame having a die pad and the temporary protective film for semiconductor encapsulation molding. The temporary protective film is attached to one surface of the lead frame in such a direction that the adhesive layer of the temporary protective film is in contact with the lead frame.

Yet another aspect of the present invention includes a lead frame having a die pad, a semiconductor element mounted on the die pad on one side of the lead frame, and a sealing layer sealing the semiconductor element. Provided is a temporarily protected encapsulation molded body comprising the above-mentioned temporary protection film for semiconductor encapsulation molding. The temporary protective film is attached to the surface of the lead frame opposite to the semiconductor element, with the adhesive layer of the temporary protective film in contact with the lead frame.

Yet another aspect of the present invention includes the step of affixing the temporary protective film for semiconductor encapsulation to one surface of a lead frame having a die pad in a direction in which the adhesive layer is in contact with the lead frame; a step of mounting a semiconductor element on the surface opposite to the temporary protective film, and forming a sealing layer for sealing the semiconductor element, and comprising the lead frame, the semiconductor element, and the sealing layer. The present invention relates to a method for manufacturing a semiconductor package, which comprises, in this order, a step of obtaining a temporarily protected sealed molded body and a step of peeling off the temporary protective film from the sealed molded body.

According to one aspect of the present invention, a semiconductor encapsulation that can be attached to a lead frame with appropriate adhesive strength and that can be easily peeled off after being subjected to a high temperature thermal history of about 400° C. A temporary protective film for molding is provided.

It is a sectional view showing one embodiment of a temporary protection film. It is a sectional view showing one embodiment of a temporary protection film. FIG. 1 is a cross-sectional view illustrating an embodiment of a method for manufacturing a semiconductor package. FIG. 1 is a cross-sectional view illustrating an embodiment of a method for manufacturing a semiconductor package. FIG. 1 is a cross-sectional view showing one embodiment of a semiconductor package. It is a perspective view showing one embodiment of a reel body. It is a front view showing one embodiment of a package. It is a front view showing one embodiment of a package.

Hereinafter, several embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The upper and lower limits of the numerical ranges described herein can be arbitrarily combined. The numerical values described in the examples can also be used as the upper limit or lower limit of the numerical range.

Temporary Protective Film FIG. 1 is a sectional view showing a temporary protective film according to one embodiment. The temporary protective film 10 shown in FIG. 1 is composed of a support film 1 and an adhesive layer 2 provided on one side of the support film 1. Adhesive layers may be formed on both sides of the support film 1. FIG. 2 is also a sectional view showing a temporary protective film according to one embodiment. The temporary protective film 10' in FIG. 2 includes 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. and has. These temporary protective films are applied to the back side of the lead frame (the side opposite to the side on which the semiconductor element is mounted) during the sealing process to form a sealing layer that seals the semiconductor element mounted on the die pad of the lead frame. By pasting it on the surface), it can be used as a temporary protective film for semiconductor encapsulation molding to temporarily protect the lead frame during encapsulation molding.

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

Thermoplastic resins include aromatic polyetheramideimide, aromatic polyetherimide, aromatic polyetheramide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamideimide, aromatic polyether, and aromatic polyester. It may contain at least one species selected from the group consisting of imides. From the standpoint of heat resistance and adhesiveness, the thermoplastic resin may be at least one selected from the group consisting of aromatic polyetheramideimide, aromatic polyetherimide, and aromatic polyetheramide; It may also be polyetheramideimide.

Aromatic polyether amide imide 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. At least one of them can be a polycondensate containing a compound having a plurality of aromatic groups and an oxy group (-O-) that connects the aromatic groups. 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. At least one of them can be a polycondensate containing a compound having a plurality of aromatic groups and an oxy that bonds the aromatic groups to each other. 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. It can be a polycondensate containing a compound at least one of which has a plurality of aromatic groups and an oxy that bonds the aromatic groups. The reactive derivative of carboxylic acid may be, for example, an acid anhydride or an acid chloride.

The aromatic polyetheramideimide and the aromatic polyamideimide may contain a structural unit derived from trimellitic acid or a reactive derivative thereof. Aromatic polyimides and aromatic polyetherimides may contain structural units derived from pyromellitic acid, polynuclear aromatic tetracarboxylic acids, or reactive derivatives thereof. Examples of polynuclear aromatic tetracarboxylic acids include bisphenol A bistrimelitate and oxydiphthalic acid. The aromatic polyamide may contain structural units derived from terephthalic acid, isophthalic acid, or reactive derivatives thereof.

Aromatic polyetheramide imide, aromatic polyetherimide and aromatic polyetheramide are, 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, It may contain a structural unit derived from an aromatic diamine having a group. Aromatic polyetheramide imide, aromatic polyetherimide, and aromatic polyetheramide are aromatic diamines having no oxy group (for example, 4,4'-methylenebis(2-isopropylaniline)), siloxane diamines (for example, 1, 3-bis(3-aminopropyl)tetramethyldisiloxane) and other diamine-derived structural units selected from α,ω-diaminoalkanes (e.g. 1,12-diaminododecane, 1,6-diaminohexane) may further include.

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

The low-molecular additive is a compound with a molecular weight of less than 1000, and can be selected based on the degree of weight loss when a film made of the thermoplastic resin and the low-molecular additive is heated. Specifically, when a film consisting of 100 parts by mass of a thermoplastic resin and 10 parts by mass of a low-molecular additive is heated from 25°C to 420°C, the weight loss rate is 10% or more based on the weight at 25°C. Certain small molecule additives are selected. Note that the temperature increase rate when heating from 25°C to 420°C is 10°C/min. The thickness of the film for measuring the weight loss rate may be 20-50 μm. When the low-molecular additive contains two or more kinds of compounds in a predetermined compounding ratio, the weight reduction rate is determined by adding those compounds in the same compounding ratio as in the adhesive layer 2 and 100 parts by mass of the thermoplastic resin. , and a low-molecular additive in a total amount of 10 parts by mass of two or more compounds. According to the findings of the present inventors, the degree of weight loss when the adhesive layer containing the low-molecular additive is heated to 420° C. is related to the releasability of the temporary protective film from the lead frame after heat treatment. The reason for this is presumed to be that when the amount of gas generated by heating is large, the adhesion at the interface between the adhesive layer and the lead frame decreases. The weight reduction rate may be 11% or more, or 12% or more, or 17% or less, or 15% or less. Note that in this specification, the low-molecular additive does not include the coupling agent described below.

From the same viewpoint as above, when a film consisting of 100 parts by mass of a thermoplastic resin and 10 parts by mass of a low-molecular additive is heated from 25°C to 420°C at a temperature increase rate of 10°C/min, the weight loss rate is: Based on the weight at 25°C, when it is X% at 300°C and Y% at 420°C, Y−X may be 7% or more.

The small molecule additive may include an epoxy compound having one or more epoxy groups (or glycidyl ether groups). The number of epoxy groups that the epoxy compound has may be 5 or less. Specific examples of epoxy compounds that provide films exhibiting 10% weight loss include sorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether, and glycerol polyglycidyl ether.

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

The epoxy equivalent of polyethylene glycol diglycidyl ether is, for example, 200 to 400 g/eq. , or 250-350g/eq. It may be.

Glycerol polyglycidyl ether is a compound having a glycerol residue 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 glycerol polyglycidyl ether is, for example, 120 to 160 g/eq. It may be.

The content of the low-molecular additive is 5 to 20 parts by mass, or 5 to 15 parts by mass per 100 parts by mass of the thermoplastic resin, from the viewpoint of peelability from the lead frame after undergoing thermal history at 400°C. It may be a department. From the same viewpoint, the content of sorbitol polyglycidyl ether may be 5 to 20 parts by mass, or 5 to 12 parts by mass based on 100 parts by mass of the thermoplastic resin, and the content of polyethylene glycol diglycidyl ether may be , 5 to 20 parts by weight, or 7 to 15 parts by weight based on 100 parts by weight of the thermoplastic resin.

で表される化合物であってよい。式（Ｉ）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に炭素数１～３のアルコキシ基、炭素数１～６のアルキル基又は炭素数６～１２のアリール基を示し、Ｘは反応性官能基を含む基を示す。 The adhesive layer may further contain one or more coupling agents apart from the low-molecular additive. The coupling agent may be a silane coupling agent. The silane coupling agent has the following formula (I):

It may be a compound represented by 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 is Indicates a group containing a reactive functional group.

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

で表される基であってよい。これら式中、Ｒ^４、Ｒ^５及びＲ^６は、炭素数１～６のアルキル基、炭素数６～１２のアリール基又は水素原子を示す。＊は炭素原子との結合部位を示す。
Ｒ^４、Ｒ^５及びＲ^６は、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔｅｒｔ－ブチル基、ペンチル基、及びヘキシル基から選ばれる炭素数１～６のアルキル基、又は、フェニル基、トリル基、キシリル基、及びナフチル基から選ばれる炭素数６～１２のアリール基であってもよい。 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 is the following formula (IIa), (IIb), (IIc), (IId), or (IIe):

It may be a group represented by 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. * indicates a bonding site with a carbon atom.
R ⁴ , R ⁵ and R ⁶ are alkyl groups having 1 to 6 carbon atoms selected from methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, and hexyl group Alternatively, it may be an aryl group having 6 to 12 carbon atoms selected from phenyl group, tolyl group, xylyl group, and naphthyl group.

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

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 is mentioned.

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 is mentioned.

Examples of silane coupling agents in which X is a group represented by formula (IId) include 3-ureidopropyltrimethoxysilane, 3-ureidopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-ureidopropyl Methyldiethoxysilane, 3-(3-phenylureido)propyltriethoxysilane, 3-(3-methylureido)propyltriethoxysilane, 3-(3-ethylureido)propyltriethoxysilane, 3-(3-propyl) ureido)propyltriethoxysilane, 3-(3-butylureido)propyltriethoxysilane, 3-(3-hexylureido)propyltriethoxysilane, 3-(3-phenylureido)propyltrimethoxysilane, 3-(3-butylureido)propyltriethoxysilane - methylureido)propyltrimethoxysilane, 3-(3-ethylureido)propyltrimethoxysilane, 3-(3-propylureido)propyltrimethoxysilane, 3-(3-butylureido)propyltrimethoxysilane, and 3 -(3-hexylureido)propyltrimethoxysilane.

Examples of silane coupling agents in which X is a group represented by formula (IIe) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxy silane, and 3-glycidoxypropylmethyldiethoxysilane.

The content of the coupling agent may be 1 to 40 parts by mass based on 100 parts by mass 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, the varnish for forming the adhesive layer 2 is less likely to undergo gelation, decrease in viscosity, etc., and the temporary protective film can be manufactured more easily. From the same viewpoint, the content of the coupling agent is 1 to 35 parts by weight, 2 to 35 parts by weight, 3 to 30 parts by weight, more than 5 parts by weight and 35 parts by weight or less, 5 parts by weight or less, based on 100 parts by weight of the thermoplastic resin. It may be more than 30 parts by mass or less, or more than 5 parts by mass and not more than 20 parts by mass.

The adhesive layer 2 may further contain a filler. Examples of fillers 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 weight, 1 to 30 parts by weight, or 5 to 15 parts by weight based on 100 parts by weight of the thermoplastic resin.

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

The thickness of the adhesive layer 2 is 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, from the viewpoint that curling of the temporary protective film is more easily suppressed. good. 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.

The support film 1 is made of, for example, aromatic polyimide, aromatic polyamide, aromatic polyamideimide, aromatic polysulfone, aromatic polyether sulfone, polyphenylene sulfide, aromatic polyether ketone, polyarylate, aromatic polyether ether ketone, and polyethylene. It may be a film of at least one polymer selected from the group consisting of naphthalates. The support film 1 may be made of copper, aluminum, stainless steel or nickel in film form. When the support film 1 is a polymer film, its surface has not been surface-treated by a method such as alkali treatment, chemical treatment such as silane coupling treatment, physical treatment such as sand mat treatment, plasma treatment, or corona treatment. It's okay.

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

The non-adhesive layer 3 is a resin layer that has substantially 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 does not easily soften at high temperatures; for example, a resin layer having a high glass transition temperature can function as the non-adhesive layer.

The resin layer as the non-adhesive layer 3 contains a thermoplastic resin, a thermosetting resin (cured product), or a resin that is 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 phenolic resin, or a bismaleimide resin. When a thermoplastic resin and a thermosetting resin are combined, the amount of the thermosetting resin may be 5 to 100 parts by weight, or 20 to 70 parts by weight, based on 100 parts by weight of the thermoplastic resin.

The non-adhesive layer 3 may contain a filler (for example, ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles), a coupling agent, and the like. The filler content in the non-adhesive layer 3 may be 1 to 30 parts by weight, or 5 to 15 parts by weight based on 100 parts by weight of the resin. The content of the coupling agent may be 1 to 20 parts by weight, or 2 to 15 parts by weight based on 100 parts by weight of the resin.

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

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.

The temporary protective film can be produced, for example, by a method that includes a step of applying a varnish containing a thermoplastic resin, an epoxy compound, and a solvent to a support film, and forming an adhesive layer by removing the solvent from the coating film. A non-adhesive layer can also be formed by a similar method.

Method for Manufacturing a Semiconductor Package A semiconductor package can be manufactured using the temporary protective film according to the embodiments illustrated above. The manufactured semiconductor package has, for example, a lead frame, a semiconductor element mounted thereon, and a sealing layer that seals the semiconductor element on the semiconductor element side of the lead frame, and the back side of the lead frame is used for external connection. It may be a Non-Lead Type Package that is exposed to Specific examples include QFN (QuadFlat Non-leaded Package) and SON (Small Outline Non-leaded Package).

3 and 4 are cross-sectional views illustrating one embodiment of a method of manufacturing a semiconductor package. FIG. 5 is a cross-sectional view showing one embodiment of a semiconductor package obtained by the manufacturing method of FIGS. 3 and 4. Hereinafter, each process will be explained with reference to each drawing as necessary.

The method shown in FIGS. 3 and 4 is a step of attaching a temporary protective film 10 to the back surface, which is one surface, of a lead frame 11 having a die pad 11a and an inner lead 11b, with its adhesive layer in contact with the lead frame 11. a step of mounting the semiconductor element 14 on the surface of the die pad 11a opposite to the temporary protective film 10; a step of providing the wire 12 connecting the semiconductor element 14 and the inner lead 11b; and a step of providing the semiconductor element 14 and the wire 12. a step of forming a sealing layer 13 for sealing to obtain a temporarily protected sealing molded body 20 having a lead frame 11, a semiconductor element 14, and a sealing layer 13; and a step of peeling off the film 10, in this order. The temporarily protected sealed molded body is composed of the sealed molded body 20 and the temporary protective film 10.

The step of attaching the temporary protective film 10 to the lead frame 11 may include heating and pressurizing the temporary protective film 10 placed on the lead frame 11. The heating temperature may be 150°C or higher, 180°C or higher, or 200°C or higher, or 400°C or lower. The pressure may be 0.5-30 MPa, 1-20 MPa, or 3-15 MPa. The heating and pressurizing time may be 0.1 to 60 seconds, 1 to 30 seconds, or 3 to 20 seconds.

The lead frame 11 may be made of, for example, an iron-based alloy such as 42 alloy, copper, or a copper-based alloy. The lead frame 11 may include a molded body made of copper or a copper-based alloy, and a coating layer of palladium, gold, silver, or the like covering the surface of the molded body.

The semiconductor element 14 is usually bonded to the die pad 11a via an adhesive (for example, silver paste). After bonding the semiconductor element 14 to the die pad 11a, reflow connection (such as CuClip connection) may be performed at a maximum temperature of 250 to 440° C. or 250 to 400° C. for 1 to 30 minutes.

The wire 12 may be, for example, but not limited to, 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 bonded 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.

The sealing layer 13 is formed by sealing molding using a sealing material. By sealing molding, a sealing molded body 20 having a plurality of semiconductor elements 14 and a sealing layer 13 that seals them all together may be obtained. During sealing molding, the provision of the temporary protective film 10 prevents the sealing material from going around to the back side of the lead frame 11.

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

The formed sealing layer 13 may be heated and 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.

Encapsulants may also be included, such as epoxy resins such as cresol novolac epoxy resins, phenol novolac epoxy resins, biphenyl diepoxy resins, naphthol novolac epoxy resins, and the like. The sealing material may contain a filler, a flame retardant substance such as a bromine compound, a wax component, and the like.

After the sealing molding to form 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 molded body 20. When the sealing layer 13 is cured, the temporary protective film 10 may be peeled off before or after the sealing layer 13 is cured.

The temperature at which the temporary protective film 10 is peeled off from the sealed molded body 20 may be 0 to 250°C, 100 to 200°C, or 150 to 250°C.

If a portion of the adhesive layer remains on the lead frame 11 and sealing layer 13 after peeling off the temporary protective film 10 from the lead frame 11, this may be removed. The remaining adhesive layer may be removed by mechanical brushing or by solvent. The solvent may be, for example, N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, or dimethyl formamide.

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

A semiconductor package may be manufactured by winding up a long temporary protective film around a core and unwinding the temporary protective film from the obtained reel. The reel body in this case includes a core and the temporary protective film according to the above-described embodiment wound around the core.

FIG. 6 is a perspective view showing one embodiment of the reel body. The reel body 30 shown in FIG. 6 includes a core 31, a temporary protective film 10 wound around the core 31, and a side plate 32. The width of the winding core 31 and the temporary protective film 10 (the length in the direction perpendicular to the winding direction) may be, for example, 0.001 cm or more, 0.005 cm or more, or 0.008 cm or more, and 0.03 cm or less. It may be. The width of the winding core 31 and the temporary protective film 10 (the length in the direction orthogonal to the winding direction) is, for example, 0.001 cm or more and 0.03 cm or less, 0.005 cm and 0.03 cm or less, or 0.008 cm or more and 0.03 cm. It may be the following.

The temporary protective 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 one embodiment of the package. As shown in FIG. 7, the package 50 includes a reel body 30 and a packaging bag 40 containing the reel body 30. The reel bodies 30 are usually individually housed in packaging bags, but a plurality of reel bodies 30 (for example, two to three pieces) may be housed in one packaging bag 40.

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

The packaging bag 40 may contain a desiccant together with the reel body 30. Examples of the desiccant include silica gel. The packaging body 50 may be a packaging bag 40 containing the reel body 30 further wrapped in a cushioning material.

The package 50 may be provided as a package housed in a packaging box. FIG. 8 shows one embodiment of the package. As shown in FIG. 8, the package 70 includes a package 50 and a packaging box 60 that accommodates the package 50. The packaging box 60 accommodates one or more packaging bodies 50. As the packaging box 60, for example, cardboard can be used.

A semiconductor package manufactured using the temporary protective film according to one embodiment is superior in terms of high density, small area, and thinness, and is suitable for electronic devices such as mobile phones, smartphones, personal computers, and tablets. It can be suitably used for.

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

1. Preparation Example 1 of temporary protective film
270.9 g (0.63 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and 67.0 g (0.63 mol) of 1,3-bis(3-aminopropyl)-tetramethyldisiloxane. An aromatic polyether amide imide, which is a polycondensate formed from 27 mol) and 187.3 g (0.89 mol) of trimellitic anhydride chloride, was prepared. 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-glycidoxypropyl. A varnish for forming an adhesive layer was obtained by dissolving 3 parts by mass of trimethoxysilane (manufactured by Dow Corning Toray Silicone Co., Ltd., trade name: SH6040) in N-methylpyrrolidone.
The resulting varnish was applied onto one side of the 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 providing temporary protection of Example 1 having the support film and adhesive layer. Got the film.

Example 2
A varnish for forming an adhesive layer 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 per 100 parts by mass of aromatic polyether amide imide. .

Example 3
Instead of sorbitol polyglycidyl ether, polyethylene glycol diglycidyl ether (manufactured by Kyoei Kagaku Co., Ltd., trade name: Epolite 400E, epoxy equivalent: 264 to 290 g/eq.) was used, and the amount was adjusted to 100 mass of aromatic polyether amide imide. A varnish for forming an adhesive layer and a temporary protective film were obtained in the same manner as in Example 1 except that the amount was 10 parts by mass.

Example 4
Glycerol polyglycidyl ether (manufactured by Nagase ChemteX Co., Ltd., trade name: EX-313, epoxy equivalent: 141 g/eq.) was used instead of sorbitol polyglycidyl ether, and the amount was changed to 100 parts by mass of aromatic polyether amide imide. A varnish for forming an adhesive layer and a temporary protective film were obtained in the same manner as in Example 1 except that the amount was 10 parts by mass.

Comparative example 1
Instead of sorbitol polyglycidyl ether, ethylene glycol diglycidyl ether (manufactured by Nagase ChemteX Co., Ltd., trade name: EX-810, epoxy equivalent: 113 g/eq.) was used, and the amount was adjusted to 100 mass of aromatic polyether amide imide. A varnish for forming an adhesive layer and a temporary protective film were obtained in the same manner as in Example 1 except that the amount was 10 parts by mass.

Comparative example 2
A varnish for forming an adhesive layer and a temporary protective film were obtained in the same manner as in Example 1 except that sorbitol polyglycidyl ether was not used.

2. Thermogravimetric analysis A film (thickness: approximately 30 μm) consisting of 100 parts by mass of the aromatic polyetheramide imide used in Example 1 and 10 parts by mass of EX-614B, Epolite 400E, EX-313, or EX-810. It was created. Each of the obtained films was analyzed by thermogravimetric analysis by heating from room temperature to 550°C at a heating rate of 10°C/min. Based on the weight at 25°C, the percentage of weight reduced by the time of heating to 420°C was determined as weight reduction rate [%]. The measurement results are shown in Table 1.

3. Peel strength (1) After attachment The temporary protective film was attached to a copper lead frame (50 mm x 200 mm, AgCu) at a temperature of 235°C, a pressure of 6 MPa, and a time of 10 seconds, with the adhesive layer in contact with the copper lead frame. . Next, the 90 degree peel strength between the adhesive layer and the lead frame at 25° C. was measured at a peeling rate of 300 mm/min.
(2) After heat treatment The temporary protective film was attached to a copper lead frame (50 mm x 200 mm, AgCu) at a temperature of 235° C., a pressure of 6 MPa, and a time of 10 seconds, with the adhesive layer in contact with the copper lead frame. Next, the copper lead frame and the temporary protective film attached thereto were subjected to heat treatment at 180° C. for 1 hour, followed by heating at 400° C. for 2 minutes. After the heat treatment, the 90 degree peel strength between the adhesive layer and the lead frame at 200° C. was measured at a peeling rate of 300 mm/min.

Table 2 shows the evaluation results of peel strength after pasting and after heat treatment. The temporary protective films of each example exhibited appropriate peel strength after application, and exhibited sufficiently reduced peel strength after heat treatment. In peel strength measurements after heat treatment in Example 4 and Comparative Example 1, it was observed that a portion of the adhesive layer remained on the lead frame after peeling, resulting in a residue.

DESCRIPTION OF SYMBOLS 1... Support film, 2... Adhesive layer, 3... Non-adhesive layer, 10,10'... Temporary protective film, 11... Lead frame, 11a... Die pad, 11b... Inner lead, 12... Wire, 13... Sealing layer, 14 ... Semiconductor element, 20... Sealing molded body, 30... Reel body, 31... Winding core, 32... Side plate, 40... Packaging bag, 50... Packaging body, 60... Packing box, 70... Packing object, 100... Semiconductor package.

Claims (7)

A support film and an adhesive layer provided on one or both sides of the support film, during sealing molding to form a sealing layer for sealing a semiconductor element mounted on a die pad of a lead frame. A temporary protective film for semiconductor encapsulation, which is used to temporarily protect the surface of a lead frame opposite to the semiconductor element,
The adhesive layer includes a thermoplastic resin , a low molecular weight additive with a molecular weight of less than 1000 , and a coupling agent different from the low molecular weight additive ,
When a film made of 100 parts by mass of the thermoplastic resin and 10 parts by mass of the low-molecular additive is heated from 25°C to 420°C, the weight loss rate is 10% or more based on the weight at 25°C,
The thermoplastic resin is aromatic polyetheramideimide, aromatic polyetherimide, aromatic polyetheramide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamideimide, aromatic polyether, and aromatic Contains at least one member selected from the group consisting of polyester imide,
The low-molecular additive contains an epoxy compound having one or more epoxy groups,
Temporary protective film for semiconductor encapsulation molding. The temporary protective film for semiconductor encapsulation molding according to claim 1, wherein the content of the low-molecular additive is 5 to 20 parts by mass based on 100 parts by mass of the thermoplastic resin. A support film and an adhesive layer provided on one or both sides of the support film, during sealing molding to form a sealing layer for sealing a semiconductor element mounted on a die pad of a lead frame. A method for manufacturing a temporary protective film for semiconductor encapsulation, which is used to temporarily protect the surface of a lead frame opposite to the semiconductor element, the method comprising:
A low-molecular additive whose weight loss rate when a film consisting of 100 parts by mass of a thermoplastic resin and 10 parts by mass of a low-molecular additive is heated from 25°C to 420°C is 10% or more based on the weight at 25°C. and select
forming an adhesive layer containing the thermoplastic resin , the selected low-molecular additive , and a coupling agent different from the low-molecular additive on one or both sides of the support film;
including ;
The thermoplastic resin is aromatic polyetheramideimide, aromatic polyetherimide, aromatic polyetheramide, aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamideimide, aromatic polyether, and aromatic Contains at least one member selected from the group consisting of polyesterimide,
The low-molecular additive contains an epoxy compound having one or more epoxy groups,
Method. a lead frame having a die pad;
A temporary protective film for semiconductor encapsulation molding according to claim 1 or 2 ,
Equipped with
A lead frame with a temporary protective film, wherein the temporary protective film is attached to one surface of the lead frame in a direction in which an adhesive layer of the temporary protective film is in contact with the lead frame. a lead frame having a die pad;
a semiconductor element mounted on the die pad on one side of the lead frame;
a sealing layer sealing the semiconductor element;
A temporary protective film for semiconductor encapsulation molding according to claim 1 or 2 ,
Equipped with
A temporarily protected encapsulation molded body, wherein the temporary protective film is attached to a surface of the lead frame opposite to the semiconductor element in a direction in which an adhesive layer of the temporary protective film is in contact with the lead frame. . A step of pasting the temporary protective film for semiconductor encapsulation molding according to claim 1 or 2 on one surface of a lead frame having a die pad, with the adhesive layer thereof in contact with the lead frame;
a step of mounting a semiconductor element on the surface of the die pad opposite to the temporary protective film;
forming a sealing layer for sealing the semiconductor element to obtain a temporarily protected sealing molded body having the lead frame, the semiconductor element, and the sealing layer;
Peeling the temporary protective film from the sealed molded body;
A method for manufacturing a semiconductor package, comprising: in this order. The lead frame has a plurality of the die pads, and the semiconductor element is mounted on each of the plurality of die pads,
Claim: The method further comprises the step of peeling off the temporary protective film from the molded seal and then dividing the molded seal to obtain one semiconductor package having the die pad and the semiconductor element. The method described in 6 .

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