Temporary protective film, reel body, package body, bale body, temporary protective body, and method of manufacturing semiconductor device

Abstract

A temporary protective film includes a support film and an adhesive layer provided on one or both sides of the support film. The support film is a polyimide film. The adhesive layer has a thickness of less than 8 μm. The temporary protective film is used to temporarily protect the side of a lead frame opposite a semiconductor element during sealing molding of a sealing layer of the semiconductor element that is sealingly mounted on the single side of the lead frame having a chip pad and internal leads.

Description

Technical Field

[0001] This invention relates to a temporary protective film, a roll, a package, a bundle, a temporary protective body, and a method for manufacturing a semiconductor device. Background Technology

[0002] Semiconductor packages sometimes employ a sealing layer formed on one side of the lead frame to seal the semiconductor element mounted on the lead frame, while the exposed side of the lead frame opposite the semiconductor element is used for external connections (Patent Documents 1 and 2). During the sealing molding process of forming the sealing layer for manufacturing this semiconductor package, to prevent the sealing material from wrapping around the back side of the lead frame opposite the semiconductor element, a temporary protective film is sometimes applied to temporarily protect the back side of the lead frame. The temporary protective film is usually peeled off from the lead frame after the sealing layer is formed.

[0003] Previous technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 5-129473

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

[0007] The technical problem to be solved by the invention

[0008] With the miniaturization and increasing complexity of semiconductor devices, in the manufacture of semiconductor devices using temporary protective films that provide temporary protection to the back of the lead frame, there is a tendency for the temporary protective film adhered to the lead frame to be subjected to higher temperatures and longer thermal histories. If the thermal histories increase, problems such as voids forming at the interface between the temporary protective film and the lead frame, and insufficient peelability of the temporary protective film after sealing become more pronounced. It is also possible that the sealing layer may begin to wrap around the lead frame from a void.

[0009] One aspect of the present invention relates to a temporary protective film that suppresses the generation of voids accompanying the sealing process and further improves peelability after sealing. During the sealing process of forming a sealing layer for sealing a semiconductor element mounted on one side of a lead frame, the temporary protective film is used to temporarily protect the side of the lead frame opposite to the semiconductor element.

[0010] means for solving technical problems

[0011] One aspect of the present invention provides a temporary protective film comprising: a support film; and an adhesive layer disposed on one or both sides of the support film. The temporary protective film according to this aspect of the present invention is used to temporarily protect the side of the lead frame opposite to the semiconductor element during the sealing process of forming a sealing layer for sealing a semiconductor element mounted on one side of a lead frame having a chip pad and internal leads. The support film is a polyimide film. The thickness of the adhesive layer is less than 8 μm.

[0012] Another aspect of the present invention provides a roll body comprising: a roll having a cylindrical winding portion; and the aforementioned temporary protective film wound around the winding portion.

[0013] Another aspect of the present invention provides a packaging body comprising the aforementioned roll body and a packaging bag containing the roll body.

[0014] Another aspect of the present invention provides a bundle body comprising the above-described packaging body and a bundle box containing the packaging body.

[0015] Another aspect of the present invention provides a temporary protective body comprising: a lead frame having a chip pad and internal leads; and the aforementioned temporary protective film. The temporary protective film is adhered to the lead frame in a manner that its adhesive layer makes single-sided contact with the lead frame.

[0016] Another aspect of the present invention provides a method for manufacturing a semiconductor device. The method of one aspect of the present invention sequentially includes: a step of attaching a temporary protective film to one side of a lead frame having a chip pad and internal leads, with the adhesive layer in contact with the lead frame; a step of mounting a semiconductor element on the side of the chip pad opposite to the temporary protective film; a step of providing a wire connecting the semiconductor element and the internal leads; a step of forming a sealing layer to seal the semiconductor element and the wire, thereby obtaining a sealed molded body having the lead frame, the semiconductor element, and the sealing layer; and a step of peeling the temporary protective film from the sealed molded body.

[0017] Invention Effects

[0018] According to one aspect of the invention, the temporary protective film can suppress the generation of voids accompanying the sealing process and further improve the peelability after sealing. During the sealing process of forming a sealing layer for sealing a semiconductor element mounted on one side of the lead frame, the temporary protective film is used to temporarily protect the side of the lead frame opposite to the semiconductor element.

[0019] The temporary protective film involved in one aspect of the present invention also has excellent properties in terms of good adhesion to the lead frame during sealing molding, as well as in suppressing curling, reducing lead frame warping and suppressing glue residue. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view showing one embodiment of the temporary protective film.

[0021] Figure 2 This is a cross-sectional view showing one embodiment of the temporary protective film.

[0022] Figure 3 This is a perspective view showing one embodiment of the scroll body.

[0023] Figure 4 This is a front view showing one embodiment of the packaging.

[0024] Figure 5 This is a front view showing one embodiment of the bundle.

[0025] Figure 6 This is a cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device.

[0026] Figure 7 This is a cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device.

[0027] Figure 8 This is a cross-sectional view showing one embodiment of a semiconductor device. Detailed Implementation

[0028] The embodiments of the present invention will now 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 in this specification can be arbitrarily combined. The numerical values ​​described in the embodiments can also be used as the upper or lower limits of the numerical ranges.

[0029] Temporary protective film

[0030] Figure 1 This is a cross-sectional view showing a temporary protective film according to one embodiment. Figure 1 The temporary protective film 10 shown consists of a supporting film 1 and an adhesive layer 2 disposed on one side of the supporting film 1. Alternatively, the adhesive layer can be formed on both sides of the supporting film 1. Figure 2 It is also a cross-sectional view showing the temporary protective film involved in one embodiment. Figure 2The temporary protective film 10' comprises: a support film 1; an adhesive layer 2 disposed on one main surface of the support film 1; and a resin layer (non-adhesive layer 3) disposed on the other main surface of the support film 1, and substantially non-adhesive. These temporary protective films, in the sealing molding process of forming a sealing layer to seal a semiconductor element mounted on a lead frame, can be adhered to the back side of the lead frame (the side opposite to the side mounting the semiconductor element) during sealing molding, and can be used as temporary protective films for temporarily protecting the back side of the lead frame.

[0031] The support film 1 is a polyimide film, particularly an aromatic polyimide film. The polyimide film exhibits high heat resistance and strong adhesion to the adhesive layer 2. If the adhesion between the support film 1 and the adhesive layer 2 is strong, the support film 1 and the adhesive layer 2 are not easily separated when the temporary protective film 10 is peeled from the lead frame.

[0032] The glass transition temperature of the supporting film 1 can be above 200°C or above 250°C, or below 300°C.

[0033] The coefficient of linear expansion of the supporting film 1 at 20–200°C can be 3.0 × 10⁻⁶. -5 / ℃ or less, 2.5×10 -5 / ℃ or below or 2.0×10 -5 / ℃ or below. If the coefficient of linear expansion of the supporting film 1 is small, there is a tendency for warping of the lead frame to which the temporary protective film 10 is attached to be suppressed. The coefficient of linear expansion of the supporting film at 20–200℃ was determined using a thermomechanical analysis apparatus (TMA) according to JIS K 7197. The chuck distance was set to 10 mm.

[0034] The shrinkage rate (heat shrinkage rate) of the support film 1 when heated at 200°C for 60 minutes can be less than 0.15%, less than 0.13%, or less than 0.10%. The heat shrinkage rate can be measured according to JIS K 7133. A CNC image measurement system (NEXIV) is used to measure the heat shrinkage rate. The heat shrinkage rate can be determined by measuring the dimensional difference of the support film in the MD direction (length direction) or TD direction (direction perpendicular to the MD direction) before and after heat treatment. The heat treatment conditions are a temperature of 200°C and a time of 60 minutes. The larger of the heat shrinkage rate in the MD direction and the heat shrinkage rate in the TD direction can be within the above range.

[0035] The supporting film 1 can be a surface-treated film. Examples of surface treatment methods for the supporting film 1 include chemical treatments such as alkali treatment and silane coupling treatment, physical treatments such as sand pad treatment, plasma treatment, and corona treatment.

[0036] The thickness of the support film 1 is not particularly limited and can be 5–100 μm or 5–50 μm. If the thickness of the support film 1 is 5 μm or more, there is a tendency for the temporary protective film 10 to be less prone to wrinkling. If the thickness of the support film 1 is less than 100 μm, there is a tendency for the warping of the lead frame to be smaller.

[0037] The thickness of adhesive layer 2 is less than 8 μm. If the thickness of adhesive layer 2 is less than 8 μm, the generation of voids during sealing is suppressed, and the peelability of the temporary protective film 10 after sealing is further improved. Furthermore, the required adhesive strength to the lead frame during sealing is easily obtained. It is believed that if adhesive layer 2 is thinner, the generation of degassing caused by heating is suppressed, resulting in suppressed void generation. From the same perspective, the thickness of adhesive layer 2 can be less than 7 μm, less than 6 μm, or less than 5 μm, or it can be 0.5 μm or more, 1 μm or more, 2 μm or more, 3 μm or more, or 4 μm or more.

[0038] The ratio (T2 / T1) of the thickness of the adhesive layer 2 to the thickness (T1) of the supporting film 1 can be 0.2 or less, 0.1 or less, or 0.05 or less. If T2 / T1 is 0.2 or less, the generation of voids associated with sealing is particularly suppressed.

[0039] The adhesive layer 2 may contain at least one organic polymer selected from aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamide imide, aromatic polyether, aromatic polyether amide imide, aromatic polyether amide, aromatic polyether amide, and aromatic polyester imide.

[0040] Adhesive layer 2 may contain aromatic polyether amide imide. Aromatic polyether amide imide may be a condensation polymer of a diamine compound containing an aromatic diamine having a phenylene oxide group and at least one of a tricarboxylic acid or its reactive derivative.

[0041] Examples of aromatic diamines with phenylene oxides used in the synthesis of aromatic polyether amide imides include 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.

[0042] Aromatic diamines with phenylene oxides can also be used in combination with other diamine compounds. Examples of other diamine compounds include aromatic diamines without phenylene oxides, such as 4,4'-methylenebis(2,6-diisopropylamine); siloxane diamines, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; and α,ω-diaminoalkanes, such as 1,12-diaminododecane and 1,6-diaminohexane.

[0043] In the total amount of diamine compounds used to synthesize aromatic polyether amide imides, the proportion of aromatic diamines with phenylene oxides can be 40–100 mol% or 50–97 mol%.

[0044] Examples of tricarboxylic acids and their reactive derivatives used in the synthesis of aromatic polyether amide imides include trimellitic anhydride and trimellitic anhydride acyl chloride.

[0045] The adhesive layer 2 may further contain a silane compound having a silyl group and a reactive group. The reactive group may be, for example, an epoxy group, an amino group, or an isocyanate group. The silane compound having an epoxy group is, for example, represented by the following formula (1).

[0046] [Chemical Formula 1]

[0047]

[0048] In equation (1), R 1 R 2 and R 3 R represents, independently, 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. 4 The alkylene group (e.g., propenyl) represents a carbon group with 1 to 10 carbon atoms. Examples of silane compounds represented by formula (1) include 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltriethoxysilane and 3-epoxypropoxypropylmethyldiethoxysilane.

[0049] The content of silane compounds can be 1–40% by mass, 1–35% by mass, 2–35% by mass, 3–30% by mass, greater than 5% by mass and less than 35% by mass, greater than 5% by mass and less than 30% by mass, or greater than 5% by mass and less than 20% by mass, relative to the amount of organic polymer (e.g., aromatic polyetheramide imide). If the content of silane compounds is 1% by mass or more, there is a tendency for the peelability of the temporary protective film after the sealing layer is formed to be further improved. If the content of silane compounds is 40% by mass or less, gelation of the varnish and reduction of viscosity are less likely to occur, thus there is a tendency for the stability of the varnish to be further improved and the production of the temporary protective film to become easier.

[0050] The adhesive layer 2 may further contain fillers (e.g., ceramic powder, glass powder, silver powder, copper powder, resin particles, and rubber particles), coupling agents (excluding substances belonging to the aforementioned silane compounds), and release agents (e.g., fluorinated surfactants, silicone-based release agents, epoxy-based curing agents), and other components. When the adhesive layer 2 contains fillers, the filler content may be 1 to 30 parts by weight or 5 to 15 parts by weight relative to 100 parts by weight of the organic polymer (e.g., aromatic polyetheramide imide).

[0051] The glass transition temperature of adhesive layer 2 can be 100–300°C, 130–280°C, or 150–250°C. If the glass transition temperature is above 100°C, the peelability of adhesive layer 2 after sealing is tended to be improved. Furthermore, poor wire connection is less likely to occur. On the other hand, if the glass transition temperature is below 300°C, the reduction in the adhesive strength of the lead frame is suppressed, thus reducing the likelihood of peeling during the transport process or leakage of the sealing material during sealing.

[0052] The 5% weight loss temperature of adhesive layer 2 can be above 300°C, 350°C, or 400°C. If the 5% weight loss temperature of adhesive layer 2 is above 300°C, there is a tendency for the lead frame and conductors to be less susceptible to contamination. The 5% weight loss temperature of adhesive layer 2 can be measured using a differential thermal balance (Seiko Instruments Inc., TG / DTA220) at a heating rate of 10°C / min.

[0053] The elastic modulus of adhesive layer 2 at 200°C can be 1 MPa or more, or 3 MPa or more. If the elastic modulus of adhesive layer 2 at 200°C is 1 MPa or more, the softening of adhesive layer 2 caused by the heat accompanying the bonding wire is suppressed, thus reducing the likelihood of poor wire bonding. The elastic modulus of adhesive layer 2 at 200°C can be less than 2000 MPa, less than 1500 MPa, or 1000 MPa. The elastic modulus of adhesive layer 2 at 200°C can be measured using a dynamic viscoelasticity measuring device (UBM Co., Ltd., Rheogel-E4000) under the conditions of a tensile mode with a chuck distance of 20 mm, a sinusoidal wave, a heating rate of 5°C / min, and a frequency of 10 Hz.

[0054] When adhesive layer 2 is heated at 120°C for 10 minutes and then at 240°C for 20 minutes, the weight reduction caused by heating at 240°C for 20 minutes, relative to the weight of the adhesive layer before heating at 240°C for 20 minutes, can be less than 0.5%. If this weight reduction is small, less degassing due to heating occurs, thus the formation of voids is particularly effectively suppressed. Furthermore, even when the temporary protective film 10 is heated for more than 1 hour, the lead frame and wires are less likely to become contaminated. From the same perspective, the weight reduction can be less than 0.3% or less than 0.1%. The lower limit for the weight reduction is 0%. The weight reduction is measured using a differential thermal balance (Seiko Instruments Inc., TG / DTA220) at a heating rate of 50°C / min.

[0055] The non-adhesive layer 3 is a resin layer that does not substantially have adhesive properties (or pressure-sensitive adhesive properties) to the lead frame at temperatures ranging from 0 to 270°C. The non-adhesive layer can be a resin layer that does not easily soften at high temperatures; for example, a resin layer with a high glass transition temperature can function as a non-adhesive layer.

[0056] The non-adhesive layer 3 contains an organic polymer. The organic polymer constituting the non-adhesive layer 3 can be a thermoplastic resin, a thermosetting resin, or a combination thereof. Thermoplastic resins can be, for example, thermoplastic resins having amide, ester, imide, ether, or sulfone groups. Thermosetting resins can be, for example, epoxy resins, phenolic resins, bismaleimide resins (e.g., bismaleimide resins using bis(4-maleimidephenyl)methane as a monomer), etc. When thermoplastic and thermosetting resins are combined, the amount of thermosetting resin can be 5 to 100 parts by weight or 20 to 70 parts by weight relative to 100 parts by weight of thermoplastic resin. When the non-adhesive layer 3 contains a thermosetting resin, the non-adhesive layer 3 is typically a cured product formed by curing the thermosetting resin.

[0057] The non-adhesive layer 3 may contain fillers (e.g., ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles), coupling agents, etc. When the non-adhesive layer 3 contains fillers, the filler content may be 1–30 parts by mass or 5–15 parts by mass relative to 100 parts by mass of the organic polymer. The coupling agent content may be 1–20 parts by mass or 2–15 parts by mass relative to 100 parts by mass of the organic polymer.

[0058] The elastic modulus of the non-adhesive layer 3 at 200°C can be 10 MPa or more, 100 MPa or more, or 1000 MPa or more. The elastic modulus of the non-adhesive layer 3 at 200°C can be determined by the same method as that used for the elastic modulus of the adhesive layer 2.

[0059] The 90-degree peel strength based on the 90-degree peel test between the non-adhesive layer 3 and the mold can be less than 5 N / m or less than 1 N / m. This 90-degree peel strength is measured, for example, 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.

[0060] The glass transition temperature of the non-adhesive layer 3 can be above 150°C, above 200°C, or above 250°C, or below 350°C or below 300°C. If the glass transition temperature of the non-adhesive layer 3 is within these ranges, the non-adhesive layer 3 is not easy to soften during the sealing molding process, and there is a tendency for the non-adhesive layer 3 to be difficult to adhere to the mold and fixture.

[0061] The thickness of the non-adhesive layer 3 can be less than 8μm, less than 7μm, less than 6μm or less than 5μm, or it can be more than 1μm, more than 2μm, more than 3μm, more than 4μm, more than 5μm or more than 6μm.

[0062] The temporary protective film 10 can be obtained, for example, by a method including the following steps: applying a varnish containing an organic polymer (e.g., aromatic polyetheramide imide), a solvent, and other components such as a silane compound used as needed, onto a support film; and forming an adhesive layer 2 by removing the solvent from the coating. Examples of solvents include N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, and dimethylformamide. A further temporary protective film 10' having a non-adhesive layer 3 can be obtained by a method further including applying a varnish to the main surface of the support film 1 on the side opposite to the adhesive layer 2, and removing the solvent from the coating.

[0063] Roll body, packaging body and bundle body

[0064] Semiconductor devices can be manufactured while a temporary protective film is being pulled out from a roll body, which is obtained by winding a long temporary protective film onto a core. Figure 3 This is a perspective view showing one embodiment of the scroll body. Figure 3 The roll body 30 shown includes a core 31, a temporary protective film 10 wound on the core 31, and a side plate 32.

[0065] The width of the core 31 and the temporary protective film 10 (the length in the direction orthogonal to the winding direction) can be, for example, 10 μm or more, 50 μm or more, or 80 μm or more, or less than 300 μm.

[0066] The roll can also be stored in a packaging bag. Figure 4 This is a front view showing one embodiment of the packaging. Figure 4 The packaging body 50 shown includes a roll body 30 and a packaging bag 40 for storing the roll body 30. One roll body 30 can be stored in one packaging bag, or multiple (e.g., 2 to 3) roll bodies 30 can be stored in one packaging bag 40.

[0067] The packaging bag 40 can be formed from a resin film or a composite film that is a resin film having an aluminum layer. Specific examples of the packaging bag 40 include plastic bags coated with aluminum. Materials for the resin film include plastics such as polyethylene, polyester, vinyl chloride, and polyethylene terephthalate. The roll 30 can also be stored in the packaging bag in a vacuum-packed state. The packaging body 50 is not limited to vacuum-packed packaging bodies.

[0068] A desiccant may also be stored in the packaging bag 40 along with the roll body 30. Silica gel can be an example of a desiccant. The packaging body 50 may further include cushioning material that wraps around the packaging bag 40 containing the roll body 30.

[0069] Packaging body 50 can also be provided as a bundle for storage in a bundle box. Figure 5 This is a front view showing one embodiment of the bundle. Figure 5 The bundle 70 shown includes a packaging body 50 and a bundle box 60 for storing the packaging body 50. One or more packaging bodies 50 are stored in a bundle box 60. The bundle box 60 may be, for example, a corrugated cardboard box.

[0070] Methods for manufacturing semiconductor devices

[0071] One embodiment involves a temporary protective film that can be used, for example, to manufacture a semiconductor device having a lead frame and a semiconductor element mounted on the lead frame, and a sealing layer that seals the semiconductor element on the semiconductor element side of the lead frame, with the back of the lead frame exposed for external connection of the semiconductor device. The manufactured semiconductor device can be a Non-Lead Type Package, and specific examples include QFN (Quad Flat Non-leaded Package) and SON (Small Outline Non-leaded Package).

[0072] Figure 6 and Figure 7 This is a cross-sectional view illustrating one embodiment of a method for manufacturing a semiconductor device. Figure 8 It means through Figure 6 and Figure 7 A cross-sectional view of an example of a semiconductor device obtained by the method described above.

[0073] Figure 6 and Figure 7 The illustrated method includes the following steps in sequence: applying a temporary protective film 10 to one side (back side) of a lead frame 11 having a chip pad 11a and internal leads 11b with the adhesive layer in contact with the lead frame, thereby obtaining a temporary protective body 15 having a lead frame 11 and a temporary protective film 10; mounting a semiconductor element 14 on the side of the chip pad 11a opposite to the temporary protective film 10; providing a wire 12 connecting the semiconductor element 14 and the internal leads 11b; forming a sealing layer 13 to seal the semiconductor element 14 and the wire 12, thereby obtaining a temporary protective body 25 having a sealing molded body 20 having a lead frame 11, a semiconductor element 14 and a sealing layer 13 and a temporary protective film 10; and peeling the temporary protective film 10 from the sealing molded body 20.

[0074] The lead frame 11 can be, for example, a metal molded body formed of an iron alloy (e.g., alloy 42), copper, or a copper alloy. The lead frame 11 can have a metal molded body containing copper or a copper alloy and a metal coating covering the surface of the metal molded body. The metal coating can contain, for example, palladium, gold, or silver.

[0075] The application of the temporary protective film 10 to the lead frame 11 may include, for example, the steps of laminating the temporary protective film 10 on the lead frame 11 and heating and pressurizing the laminate composed of the lead frame 11 and the temporary protective film 10.

[0076] The temporary protective film 10 can be laminated onto the lead frame 11 at room temperature (e.g., 5–35°C). There are no particular limitations on the lamination method; for example, it can be a roll lamination method.

[0077] The temperature at which the laminate composed of lead frame 11 and temporary protective film 10 is heated can be, for example, 150–400°C, 180–350°C, or 200–300°C. The pressure applied to the laminate can be, for example, 0.5–30 MPa, 1–20 MPa, or 3–15 MPa. The heating and pressurization time can be, for example, 0.1–60 seconds, 1–30 seconds, or 3–20 seconds. Alternatively, the laminate can be preheated before heating and pressurization.

[0078] When the temporary protective film 10 is adhered to the lead frame 11 in contact with the adhesive layer 2, the peel strength (hereinafter sometimes referred to as "post-adhesion peel strength") between the adhesive layer 2 and the lead frame 11 at 25°C can be 5 N / m or more, 50 N / m or more, 100 N / m or more, or 150 N / m or more. If the post-adhesion peel strength is less than 5 N / m, not only will the temporary protective film 10 easily peel off from the lead frame 11, but problems may also occur such as the sealant entering between the lead frame 11 and the adhesive layer 2 during the sealing process. The post-adhesion peel strength can be less than 2000 N / m, less than 1500 N / m, or less than 1000 N / m.

[0079] The peel strength after application is measured, for example, according to the 90-degree peel method of JIS Z 0237, by peeling the temporary protective film relative to the lead frame at a 90-degree angle. Specifically, the 90-degree peel strength is measured at 25°C when the temporary protective film is peeled at a speed of 270–330 mm / min or 300 mm / min.

[0080] The peel strength after bonding can vary depending on the glass transition temperature (Tg) of adhesive layer 2, the heating and pressurizing temperatures, the material of the bonded materials, and the wettability of adhesive layer 2. Therefore, to achieve a peel strength of 5 N / m or higher after bonding, optimal conditions should be appropriately selected considering the glass transition temperature (Tg) of adhesive layer 2, the heating temperature used for bonding, the material of the lead frame, and the wettability of adhesive layer 2. Among these, the glass transition temperature (Tg) of adhesive layer 2 and the bonding temperature have a significant impact on the peel strength after bonding. For example, the heating temperature used for bonding can also be approximately 0–30°C higher than the glass transition temperature (Tg) of adhesive layer 2.

[0081] Regarding the peel strength after pasting, for example, a copper lead frame, a copper lead frame coated with palladium, or a 42 alloy lead frame can be used as the lead frame 11, and the temporary protective film 10 can be pasted onto the lead frame 11 under any of the following conditions: (1) temperature 230°C, pressure 6 MPa, time 10 seconds; (2) temperature 350°C, pressure 3 MPa, time 3 seconds; or (3) temperature 250°C, pressure 6 MPa, time 10 seconds.

[0082] Semiconductor element 14 is typically mounted on chip pad 11a via an adhesive (e.g., silver paste). The adhesive can be cured by heat treatment (e.g., 140–200°C for 30 minutes to 2 hours).

[0083] Alternatively, after mounting the semiconductor element 14 on the chip pad 11a, a reflow connection (such as a CuClip connection) can be performed at a maximum temperature of 250–400°C for 1–30 minutes.

[0084] There are no particular limitations on the wire 12; for example, it can be a gold wire, a copper wire, or a palladium-coated copper wire. For example, it can also be heated at 200–270°C for 3 minutes to 6 hours, and the semiconductor element and internal leads can be bonded to the wire 12 using ultrasound and pressing pressure.

[0085] A temporary protective body 25 with a sealed molded body 20 is formed by using a sealing material in a sealing molding process. The sealed molded body 20 has a plurality of semiconductor elements 14 and a sealing layer 13 that seals them together. During the sealing molding process, the sealing material is prevented from wrapping around the back side of the lead frame 11 by providing a temporary protective film 10.

[0086] One embodiment of the temporary protective body 25 includes: a lead frame 11 having a chip pad 11a and internal leads 11b; a semiconductor element 14 mounted on the chip pad 11a; a wire 12 connecting the semiconductor element 14 and the internal leads 11b; a sealing layer 13 sealing the semiconductor element 14 and the wire 12; and a temporary protective film 10. The adhesive layer 2 of the temporary protective film 10 is adhered to the back side of the lead frame 11, opposite to the side where the semiconductor element 14 is mounted.

[0087] The temperature during the formation of the sealing layer 13 can be 140–200°C or 160–180°C. The pressure during the formation of the sealing layer 13 can be 6–15 MPa or 7–10 MPa. The heating time during sealing molding can be 1–5 minutes or 2–3 minutes. The sealing layer 13 can be formed, for example, by compression molding or transfer molding.

[0088] The formed sealing layer 13 can also be cured by heating as needed. The heating temperature for curing the sealing layer 13 can be 150-200℃ or 160-180℃. The heating time for curing the sealing layer 13 can be 4-7 hours or 5-6 hours.

[0089] The sealing material can be selected from materials commonly used as sealing materials for semiconductor components. For example, the sealing material may contain epoxy resins such as cresol phenolic varnish epoxy resin, phenolic phenolic varnish epoxy resin, biphenyl diepoxide epoxy resin, and naphthol phenolic varnish epoxy resin. The sealing material may further contain additives such as fillers, flame-retardant substances such as bromine compounds, and wax components. An example of a commercially available sealing material is GE-300LC2MA2 (manufactured by Hitachi Chemical Company).

[0090] After the sealing molding of the sealing layer 13 is completed, the temporary protective film 10 is peeled off from the lead frame 11 and the sealing layer 13 of the sealing mold 20. In the case of curing the sealing layer 13, the temporary protective film 10 can be peeled off at any time before or after the curing of the sealing layer 13.

[0091] The temperature at which the temporary protective film 10 can be peeled off from the sealed molded body 20 can be 0–250°C. If the peeling temperature is above 0°C, the adhesive layer is less likely to remain on the lead frame 11 and the sealing layer 13. If the peeling temperature is below 250°C, there is a tendency for further degradation of the lead frame 11 and the sealing layer 13 to be suppressed. For the same reason, the peeling temperature can be 100–250°C or 150–250°C.

[0092] A temporary protective film 10 is adhered to the lead frame 11 in contact with the adhesive layer 2. A semiconductor element 14 is mounted on the side of the chip pad opposite to the temporary protective film 10. Then, the semiconductor element 14, the lead frame 11, and the temporary protective film 10 are heated at 240°C for 3 hours. When a sealing layer 13 is formed that contacts the adhesive layer 2 and seals the semiconductor element 14, the peel strength at 90 degrees Celsius at 180°C between the adhesive layer 2 and the lead frame 11 and the sealing layer 13 (hereinafter sometimes referred to as "post-sealing peel strength") can be 600 N / m or less. The post-sealing peel strength can be 500 N / m or less, or 450 N / m or less, or it can be 0 N / m or more, 3 N / m or more, or 5 N / m or more.

[0093] The peel strength after sealing was measured according to the 90-degree peel method of JIS Z 0237, by peeling the temporary protective film 10 relative to the lead frame 11 and the sealing layer 13 at a 90-degree angle. Specifically, the 90-degree peel strength was measured using a heated 90° peel tester (manufactured by TESTERSANGYO CO,.LTD.) at 180°C, peeling the temporary protective film at a speed of 270–330 mm / min or 300 mm / min. The peel strength after sealing was measured after sealing. Sealing was performed, for example, at a temperature of 180°C, a pressure of 7 MPa, and a molding time of 2 minutes. Then, the peel strength after sealing could also be measured after the sealing material had been cured at 180°C for 5 hours.

[0094] The method for manufacturing a semiconductor device may, as needed, include a step of removing the adhesive layer (residue) remaining on the lead frame 11 and the sealing layer 13 after the step of peeling the temporary protective film 10 from the sealing molded body 20. The adhesive layer remaining on the lead frame 11 and the sealing layer 13 can be removed by mechanical brushing, solvents, etc. The solvent is not particularly limited and can be N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, dimethylformamide, etc.

[0095] When the lead frame contains multiple patterns with chip pads and internal leads, the sealing molded body 20 can be divided as needed to obtain multiple pieces, each with a semiconductor element. Figure 8 Semiconductor device 100.

[0096] 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 involved in one embodiment may further include the step of dividing the sealing mold 20 before or after peeling the temporary protective film 10 (or 10') from the sealing mold 20 to obtain a semiconductor device 100 having a chip pad 11a and a semiconductor element 14.

[0097] Semiconductor devices manufactured using the temporary protective film according to one embodiment are superior in terms of high density, small area, and thinness, and can be preferably used in electronic devices such as mobile phones, smartphones, personal computers, and tablet computers.

[0098] Example

[0099] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments.

[0100] 1. Prepare a varnish for forming an adhesive layer.

[0101] Varnish 1

[0102] In a 5000 ml four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionation column, under a nitrogen atmosphere, 270.9 g (0.66 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 8.7 g (0.035 mol) of 1,3-bis(3-aminopropyl)-tetramethyldisiloxane were added and dissolved in 1950 g of N-methyl-2-pyrrolidone (NMP) to prepare a reaction solution. After cooling the reaction solution to 0 °C, 149.5 g (0.71 mol) of trimellitic anhydride acyl chloride was added. After the trimellitic anhydride acyl chloride dissolved, 100 g of triethylamine was further added. The reaction solution was stirred at room temperature for 2 hours, then heated to 180 °C, and the imidization was completed after 5 hours of reaction. The reaction solution was then added to methanol to precipitate the generated polyetheramide imide. The precipitated polyetheramide imide was dried and dissolved in NMP. The solution was added to methanol to precipitate the polyetheramide imide again. The precipitated polyetheramide imide was dried under reduced pressure to obtain purified powdered polyetheramide imide. 22 g of the obtained aromatic polyetheramide imide and 6.6 g of 3-epoxypropoxypropyltrimethoxysilane (manufactured by DowCorning Toray Silicone Co., Ltd., trade name: SH6040) were dissolved in 78 g of NMP to obtain varnish 1 for forming the adhesive layer.

[0103] Varnish 2

[0104] In a 1000 ml four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and cooling tube, under a nitrogen atmosphere, 120.9 g (0.41 mol) of 1,3-bis(3-aminophenoxy)benzene and 44.0 g (0.18 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane were added and dissolved in 538.3 g of NMP to prepare a reaction solution. After cooling the reaction solution to 0 °C, 125.0 g (0.59 mol) of trimellitic anhydride chloride was added. After stirring the reaction solution at room temperature (25 °C) for 1 hour, 72.6 g of triethylamine was added. After further stirring at room temperature (25 °C) for 1 hour, the reaction solution was stirred at 180 °C for 6 hours. Then, the reaction solution was added to water to precipitate the generated polyetheramide imide. The precipitated polyetheramide imide was dried and dissolved in NMP. The solution was added to water to precipitate the polyetheramide imide again. The precipitated polyetheramide imide was dried under reduced pressure to obtain purified powdered polyetheramide imide. 22 g of the obtained aromatic polyetheramide imide and 0.66 g of 3-epoxypropoxypropyltrimethoxysilane (manufactured by Dow Corning Toray Silicone Co., Ltd., trade name: SH6040) were dissolved in 78 g of NMP to obtain varnish 2 for forming the adhesive layer.

[0105] varnish 3

[0106] In a 5000 ml four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and cooling tube, under a nitrogen atmosphere, 253.3 g (0.81 mol) of 1,3-bis(3-aminophenoxy)benzene and 8.7 g (0.035 mol) of 1,3-bis(3-aminopropyl)-tetramethyldisiloxane were added and dissolved in 1500 g of NMP to prepare a reaction solution. After cooling the reaction solution to 0 °C, 239.7 g (1.14 mol) of trimellitic anhydride acyl chloride was added. After stirring the reaction solution at room temperature for 1 hour, the temperature was raised to 180 °C, and imidization was completed after 5 hours of reaction. The reaction solution was added to methanol to precipitate the generated polyetheramide imide. The precipitated polyetheramide imide was dried and dissolved in NMP. The solution was then added to methanol to precipitate the polyetheramide imide again. The precipitated polyetheramide imide was dried under reduced pressure to obtain purified powdered polyetheramide imide. 22 g of the obtained aromatic polyetheramide imide and 6.6 g of 3-ureapropyltriethoxysilane (50% methanol solution) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBE585) were dissolved in 78 g of NMP to obtain varnish 3 for forming the adhesive layer.

[0107] 4 varnish

[0108] The following acrylic rubber and epoxy resin have been prepared.

[0109] • Acrylic rubber: WS-023EK30 (trade name, manufactured by Nagase ChemteX Corporation, weight average molecular weight: 500,000 (reference value), glass transition temperature (theoretical value calculated based on copolymer ratio): -10℃)

[0110] • Epoxy resin: EX-614B (trade name, manufactured by Nagase ChemteX Corporation, sorbitol polyglycidyl ether, epoxy equivalent: 174 (reference value))

[0111] 50g of acrylic rubber (30% by mass), 1.5g of epoxy resin, and cyclohexanone were mixed and stirred to obtain a varnish 4 with a concentration of 10% by mass of components other than solvent.

[0112] 2. Prepare a varnish for forming a non-adhesive layer.

[0113] varnish 5

[0114] In a 5-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionation column, under a nitrogen atmosphere, 172.4 g (0.42 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 153.7 g (0.42 mol) of 4,4'-methylenebis(2,6-diisopropylaniline) were added and dissolved in 1550 g of NMP to prepare a reaction solution. After cooling the reaction solution to 0°C, 174.7 g (0.83 mol) of trimellitic anhydride chloride was added. After the trimellitic anhydride chloride dissolved, 130 g of triethylamine was further added. The reaction solution was stirred at room temperature (25°C) for 2 hours, then heated to 180°C, and the imidization was completed after 5 hours of reaction. The reaction solution was then added to water to precipitate the generated polyetheramide imide. The precipitated polyetheramide imide was dried and dissolved in NMP. The solution was added to water to precipitate the polyetheramide imide again. The precipitated polyetheramide imide was dried under reduced pressure to obtain purified powdered polyetheramide imide. 120 g of the obtained aromatic polyetheramide imide and 6 g of 3-epoxypropoxypropyltrimethoxysilane (manufactured by Dow Corning Toray Silicone Co., Ltd., trade name: SH6040) were dissolved in 360 g of NMP to obtain varnish 5 for forming a non-adhesive layer.

[0115] 3. Preparation of temporary protective film

[0116] Polyimide film (manufactured by DU PONT-TORAY CO.,LTD., trade name: Kapton EN) with a linear expansion coefficient of 1.5 × 10⁻⁶ at 20–200°C was prepared. -5 A support film (with a shrinkage rate of 0.02% when heated at 200°C for 60 minutes) was used. Each varnish shown in Table 1 for forming an adhesive layer was applied to one side of the support film, and the coating was allowed to dry, thereby forming the adhesive layer. In the case of forming a non-adhesive layer, varnish 5 for forming a non-adhesive layer was applied to the other side of the support film, and the coating was allowed to dry, thereby forming the non-adhesive layer. The thicknesses of the adhesive and non-adhesive layers in the temporary protective films of each embodiment and comparative example are also shown in Table 1.

[0117] 4. Glass transition temperatures of adhesive and non-adhesive layers

[0118] The glass transition temperatures of each adhesive and non-adhesive layer were determined using a thermomechanical analysis apparatus (Seiko Instruments Inc., SSC5200 model) under tensile conditions, with a chuck distance of 10 mm, a temperature range of 30 °C to 300 °C, and a heating rate of 10 °C / min.

[0119] [Table 1]

[0120]

[0121] 5. The percentage of weight loss caused by heating

[0122] The weight reduction of the adhesive layer of the temporary protective film of each embodiment and comparative example was measured when it was sequentially heated at 120°C for 10 minutes and at 240°C for 20 minutes. The weight reduction after heating at 120°C for 10 minutes was W0, and the weight after heating at 240°C for 20 minutes was W1. The weight reduction was calculated using the following formula.

[0123] Weight reduction percentage (%) = {(W0-W1) / W0} × 100

[0124] 6.90 degrees peel strength

[0125] (1) After pasting

[0126] The following leadframe with chip pads and internal leads has been prepared.

[0127] • Cu: Copper lead frame (50mm × 200mm)

[0128] • PPF: Palladium-coated copper lead frame (50mm × 200mm)

[0129] The adhesive layers of each temporary protective film were adhered to the lead frame of Cu or PPF under the adhesion conditions shown in Table 2. In the case of the temporary protective film of Comparative Example 2, the adhesive layer was tacky at room temperature (25°C), so the temporary protective film was adhered to the lead frame at room temperature using a hand roller under a load of 20N. The combination of the lead frame and the temporary protective film is shown in Table 2. The 90-degree peel strength between the adhesive layer and the lead frame at 25°C was determined by a 90-degree peel test (peeling speed: 300 mm per minute) on which the temporary protective film was peeled from the lead frame.

[0130] (2) After sealing

[0131] Semiconductor components were bonded to the chip pads of each leadframe, on which a temporary protective film was adhered. The silver paste was cured by heating at 180°C for 60 minutes. Next, gold wires, serving as conductors, were heated at 240°C for 3 hours, thereby connecting them to the semiconductor components and internal leads. Then, using a sealing material (GE-300LC2MA2, manufactured by Hitachi Chemical Company), a sealing layer was formed to seal the semiconductor components at 180°C, 7 MPa, and 2 minutes. After sealing, the 90-degree peel strength at 180°C was determined by peeling the temporary protective film from the leadframe and sealing layer at a 90-degree peel rate (300 mm / min).

[0132] [Table 2]

[0133]

[0134] As shown in Table 2, the temporary protective films of the embodiments exhibited relatively high 90-degree peel strength after application and relatively low 90-degree peel strength after sealing, indicating a degree of peelability. Observing the results of the formed sealed molded body, no voids were observed accompanying the sealing molding in the cases of the embodiments. The temporary protective films of Comparative Examples 1, 3, and 4, which had a 90-degree peel strength exceeding 600 N / m after sealing, broke upon peeling from the lead frame after sealing and therefore could not be peeled from the sealed molded body.

[0135] Symbol Explanation

[0136] 1-Supporting film, 2-Adhesive layer, 3-Non-adhesive layer, 10, 10'-Temporary protective film, 11-Lead frame, 11a-Chip pad, 11b-Internal lead, 12-Wire, 13-Sealing layer, 14-Semiconductor element, 15-Temporary protective body, 20-Sealed molding body, 25-Temporary protective body, 30-Roll body, 31-Roll core, 32-Side plate, 40-Packaging bag, 50-Packaging body, 70-Bundle body, 100-Semiconductor device.

Claims

1. A temporary protective film, comprising: Supporting film; and An adhesive layer is disposed on one or both sides of the supporting film. The supporting film is a polyimide film. The thickness of the adhesive layer is less than 8 μm. The adhesive layer contains: Selected from at least one organic polymer from aromatic polyamides, aromatic polyesters, aromatic polyimides, aromatic polyamide-imides, aromatic polyethers, aromatic polyetheramide-imides, aromatic polyether amides, aromatic polyether amides, aromatic polyester imides, and aromatic polyether imides; and Silane compounds containing silane groups and reactive groups, The content of the silane compound is 15-35% by mass relative to the amount of the organic polymer. During the sealing process of forming a sealing layer for a semiconductor element mounted on one side of a lead frame having a chip pad and internal leads, the temporary protective film is used to temporarily protect the side of the lead frame opposite to the semiconductor element. Furthermore, the temporary protective film is adhered to the lead frame in such a way that the adhesive layer contacts the lead frame. A semiconductor element is mounted on the side of the chip pad opposite to the temporary protective film. Then, after heating the semiconductor element, the lead frame, and the temporary protective film at 240°C for 3 hours, when a sealing layer is formed that contacts the adhesive layer and seals the semiconductor element, the 90-degree peel strength between the adhesive layer and the lead frame and the sealing layer is less than 600 N / m at 180°C.

2. The temporary protective film according to claim 1, wherein, The thickness of the adhesive layer is less than 5 μm.

3. The temporary protective film according to claim 1, wherein, The silane compound is represented by the following formula (1), [Chemical Formula 1] R 1 R 2 and R 3 R represents, independently, 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. 4 Indicates alkylene groups having 1 to 10 carbon atoms.

4. The temporary protective film according to any one of claims 1 to 3, wherein, When the adhesive layer is heated at 120°C for 10 minutes and then at 240°C for 20 minutes, the weight reduction caused by heating at 240°C for 20 minutes is less than 0.5% of the weight of the adhesive layer before heating at 240°C for 20 minutes.

5. The temporary protective film according to any one of claims 1 to 3, further comprising a non-adhesive layer. The adhesive layer is provided on one main surface of the support film, and the non-adhesive layer is provided on the other main surface of the support film.

6. A scroll body comprising: A scroll, having a core; and The temporary protective film according to any one of claims 1 to 5 is wound around the core.

7. A packaging body comprising the roll body as described in claim 6 and a packaging bag containing the roll body.

8. The packaging body according to claim 7, further comprising a desiccant contained in the packaging bag.

9. The packaging body according to claim 7 or 8, further comprising cushioning material for wrapping the packaging bag.

10. A bundle comprising a packaging body according to any one of claims 7 to 9 and a bundle box containing said packaging body.

11. A temporary protective structure, comprising: Leadframe with chip pads and internal leads; and The temporary protective film according to any one of claims 1 to 5, The temporary protective film is adhered to the lead frame in a manner that its adhesive layer makes single-sided contact with the lead frame.

12. The temporary protective body according to claim 11, further comprising: Semiconductor components are mounted on the chip pad; Wires connecting the semiconductor element to the internal leads; and A sealing layer that seals the semiconductor element and the wire.

13. The temporary protective structure according to claim 11 or 12, wherein, The lead frame has a metal molded body containing copper or a copper alloy and a metal coating covering the surface of the metal molded body.

14. A method for manufacturing a semiconductor device, comprising, in sequence: The process of pasting a temporary protective film according to any one of claims 1 to 5 onto one side of a lead frame having a chip pad and internal leads, with the adhesive layer in contact with the lead frame. The process of mounting a semiconductor element on the side of the chip pad opposite to the temporary protective film; The process of setting up a wire connecting the semiconductor element and the internal leads; A process of forming a sealing layer to seal the semiconductor element and the wires, thereby obtaining a sealed molded body having the lead frame, the semiconductor element, and the sealing layer; and The process of peeling the temporary protective film off the sealed molded body.

15. The method according to claim 14, wherein, The lead frame has a plurality of chip pads, each of which has a semiconductor element mounted on it. The method further includes the step of splitting the sealant before or after peeling the temporary protective film from the sealant to obtain a semiconductor device having one of the chip pads and the semiconductor element.

16. The method according to claim 14 or 15, wherein, The lead frame has a metal molded body containing copper or a copper alloy and a metal coating covering the surface of the metal molded body.

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