Temporary protective film for semiconductor encapsulation, lead frame with temporary protective film, encapsulated molded body with temporary protective film, and method for manufacturing semiconductor device

Abstract

Provided is a temporary protective film for semiconductor encapsulation molding which includes a support film, an adhesive layer that is formed on one surface of the support film, and a non-adhesive layer that is formed on the surface of the support film opposite the surface on which the adhesive layer is formed. The non-adhesive layer has a thickness of 10 μm or less. The surface of the non-adhesive layer opposite the surface that contacts the support film has a surface roughness Ra of 0.1 μm or more.

Description

[Technical Field]

[0001] The present invention relates to a temporary protective film for semiconductor encapsulation, a lead frame with a temporary protective film, an encapsulated molded article with a temporary protective film, and a method for manufacturing a semiconductor device. [Background technology]

[0002] Conventionally, semiconductor packages have been used in which a semiconductor element is attached to a die pad with an adhesive such as silver paste, and the semiconductor element is connected to a lead frame with wires, and the entire package is sealed except for the outer leads for external connection. However, in recent years, with the increasing demand for higher density, smaller area, and thinner semiconductor packages, various semiconductor package structures have been proposed. Examples include LOC (lead chip) and COL (chip on lead) structures, but these also have limitations in terms of reducing area and thickness.

[0003] To solve these problems, packages have been developed in which only one side of the package (the semiconductor element side) is sealed, with the exposed lead frame on the back side being used for external connection (Patent Documents 1 and 2). In packages with this structure, the lead frame does not protrude from the sealing resin, so the package can be made smaller in area and thinner. One method for manufacturing a semiconductor device with this package structure is a manufacturing method consisting of the following steps.

[0004] (1) A step of attaching a temporary protective film for semiconductor encapsulation to a back surface, which is one surface of a lead frame having a die pad and inner leads; (2) a step of mounting or adhering a semiconductor element on the surface of the die pad opposite the temporary protective film; (3) providing wires that connect the semiconductor element and the inner leads; (4) forming an encapsulating layer that encapsulates the semiconductor element and the wires to obtain an encapsulated molded body having the lead frame, the semiconductor element, and the encapsulating layer; and (5) A step of peeling off the temporary protective film from the sealed molded body.

[0005] In manufacturing a semiconductor package using this method, problems may occur, such as the encapsulation resin getting around to the back surface of the lead frame during encapsulation molding. A known method for preventing such problems is to attach a temporary protective film as an adhesive film for semiconductors to the back surface of the lead frame to protect the back surface of the lead frame, and then peel off the temporary protective film after encapsulating a semiconductor element mounted on the surface opposite to the back surface of the lead frame. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 5-129473 [Patent Document 2] Japanese Patent Application Publication No. 10-12773 Summary of the Invention [Problem to be solved by the invention]

[0007] The temporary protective films used in the manufacture of semiconductor devices must be able to withstand the heat of the semiconductor assembly process, and so polyimide films are often used as the substrate (support film). However, when a resin film such as a polyimide film is used, there are cases where transport problems occur during the manufacturing process due to poor slipperiness during transport within the device.

[0008] Therefore, one aspect of the present invention provides a temporary protective film for semiconductor encapsulation molding that can suppress problems with transportation on a stage in the manufacturing process of a semiconductor device. [Means for solving the problem]

[0009] One aspect of the present invention relates to a temporary protective film for semiconductor encapsulation, which temporarily protects a lead frame during encapsulation to form an encapsulating layer that encapsulates a semiconductor element mounted on the lead frame. The temporary protective film comprises a support film, an adhesive layer provided on one side of the support film, and a non-adhesive layer provided on the side of the support film opposite the side on which the adhesive layer is provided. The thickness of the non-adhesive layer is 10 μm or less. The surface roughness of the side of the non-adhesive layer opposite the side in contact with the support film is 0.1 μm or more. The surface roughness Ra is a value measured using a laser microscope with an objective lens magnification of 50x. The surface roughness Ra can be a value calculated in accordance with the JIS B0601:2001 standard.

[0010] When the temporary protective film is attached to a lead frame having a die pad and an inner lead so that the adhesive layer is in contact with the lead frame, the 90-degree peel strength between the adhesive layer and the lead frame may be 5 N / m or more at 25°C.

[0011] When a temporary protective film is attached to a lead frame having a die pad and inner leads so that the adhesive layer is in contact with the lead frame, a semiconductor element is mounted on the surface of the die pad opposite the temporary protective film, and an encapsulating layer is formed that encapsulates the semiconductor element while in contact with the adhesive layer, the 90-degree peel strength between the adhesive layer and the lead frame and encapsulating layer may be 1000 N / m or less in at least a part of a temperature range of 0 to 250°C, at least a part of a temperature range of 80 to 250°C, or at the temperature when the temporary protective film is peeled off from the lead frame and encapsulating layer.

[0012] The adhesive layer may have a glass transition temperature of 100 to 300°C. The adhesive layer may have a modulus of elasticity of 1 MPa or more at 230°C. The adhesive layer may have a 5% weight loss temperature of 300°C or more. The adhesive layer may contain a thermoplastic resin having at least one functional group selected from the group consisting of an amide group, an ester group, an imide group, an ether group, and a sulfone group, or a thermoplastic resin having at least one functional group selected from the group consisting of an amide group, an ester group, an imide group, and an ether group.

[0013] The support film may be a film containing a polymer selected from the group consisting of aromatic polyimide, aromatic polyamide, aromatic polyamideimide, aromatic polysulfone, aromatic polyethersulfone, polyphenylene sulfide, aromatic polyetherketone, polyarylate, aromatic polyetheretherketone, and polyethylene naphthalate. The ratio of the thickness of the adhesive layer to the thickness of the support film may be 0.5 or less. The modulus of elasticity of the non-adhesive layer at 230°C may be 10 MPa or more.

[0014] Another aspect of the present invention relates to a reel body including a winding core and the temporary protective film wound around the winding core.

[0015] Another aspect of the present invention relates to a lead frame with a temporary protective film, comprising a lead frame having a die pad and an inner lead, and the temporary protective film, wherein the temporary protective film is attached to the lead frame so that its adhesive layer contacts one side of the lead frame.

[0016] One aspect of the present invention relates to an encapsulated molded body with a temporary protective film, comprising a lead frame having a die pad and inner leads, a semiconductor element mounted on the die pad, wires connecting the semiconductor element and the inner leads, an encapsulating layer encapsulating the semiconductor element and the wires, and the temporary protective film, wherein the adhesive layer of the temporary protective film is attached to the surface of the lead frame opposite to the surface on which the semiconductor element is mounted.

[0017] One aspect of the present invention relates to a method for manufacturing a semiconductor device, comprising the steps of: attaching the temporary protective film to one side of a lead frame having a die pad and inner leads, with the adhesive layer facing the lead frame; mounting a semiconductor element on the side of the die pad opposite the temporary protective film; providing wires that connect the semiconductor element and the inner leads; forming an encapsulating layer that encapsulates the semiconductor element and the wires to obtain an encapsulated molded body having the lead frame, the semiconductor element, and the encapsulating layer; and peeling the temporary protective film from the encapsulated molded body, in this order.

[0018] The method for manufacturing a semiconductor device may further include a step of connecting the semiconductor element mounted on the die pad and the inner leads with a conductive material by reflow. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a temporary protective film for semiconductor encapsulation that can suppress problems in transport on a stage in the manufacturing process of a semiconductor device.

[0020] According to the temporary protective film for semiconductor encapsulation of the present invention, it is possible to suppress the possibility of jamming by suppressing transport problems. Therefore, by using the temporary protective film for semiconductor encapsulation of the present invention, it is possible to improve the productivity of semiconductor devices. Furthermore, the temporary protective film for encapsulation of the present invention also has various properties required for semiconductor applications, such as suppressing curling and warping of lead frames. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a cross-sectional view showing one embodiment of a temporary protective film. [Figure 2] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing a semiconductor device. [Figure 3] 1A to 1C are cross-sectional views illustrating an embodiment of a method for manufacturing a semiconductor device. [Figure 4] 1 is a cross-sectional view showing an embodiment of a semiconductor device. [Figure 5] FIG. 10 is a diagram showing measurement points for warpage of a lead frame with a temporary protective film. [Figure 6] FIG. 1 is a perspective view showing an embodiment of a reel body. [Figure 7] FIG. 1 is a front view showing one embodiment of a package. [Figure 8] FIG. 1 is a front view showing one embodiment of a package. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. The upper and lower limit values ​​of the numerical ranges described in this specification can be combined arbitrarily. The numerical values ​​described in the examples can also be used as the upper or lower limit values ​​of the numerical ranges.

[0023] <Temporary protective film> Fig. 1 is a cross-sectional view showing a temporary protective film according to one embodiment. The temporary protective film 10 in Fig. 1 comprises a support film 1, an adhesive layer 2 provided on one main surface of the support film 1, and a non-adhesive layer 3 (a resin layer having substantially no adhesive properties) provided on the other main surface of the support film 1 while in contact with the support film 1. These temporary protective films can be used as temporary protective films for semiconductor encapsulation to temporarily protect the lead frame during encapsulation by being attached to the back surface of the lead frame (the surface opposite to the surface on which the semiconductor element is mounted) in the encapsulation molding process to form an encapsulation layer that encapsulates the semiconductor element mounted on the lead frame.

[0024] When the temporary protective film is attached to a lead frame having a die pad and inner leads so that the adhesive layer is in contact with the lead frame, the 90-degree peel strength (post-application peel strength) between the adhesive layer and the lead frame at 25°C may be 5 N / m or more, 10 N / m or more, 50 N / m or more, 100 N / m or more, or 150 N / m or more. If the post-application peel strength is 5 N / m or more at 25°C, the temporary protective film is less likely to peel from the lead frame, and problems such as the encapsulation resin getting between the lead frame and the adhesive layer during encapsulation molding tend to be suppressed. The post-application peel strength may be 2000 N / m or less, 1500 N / m or less, or 1000 N / m or less at 25°C.

[0025] The peel strength after application is measured, for example, by peeling the temporary protective film at a 90-degree angle relative to the lead frame in accordance with the 90-degree peel method of JIS Z 0237. Specifically, the 90-degree peel strength is measured when the temporary protective film is peeled at a speed of 270 to 330 mm per minute or 300 mm per minute at 25°C using a 90-degree peel tester (manufactured by Tester Sangyo Co., Ltd.).

[0026] The peel strength after application depends on the glass transition temperature (Tg) of the adhesive layer, the adhesive temperature, the material of the adherend, the wettability of the adhesive layer, etc. Therefore, conditions can be appropriately selected taking into account the glass transition temperature (Tg) of the adhesive layer, the adhesive temperature, the material of the lead frame, the wettability of the adhesive layer, etc., so that the peel strength after application is 5 N / m or more. Among these, the glass transition temperature (Tg) of the adhesive layer and the application (adhesion) temperature have a significant effect on the peel strength. Usually, an adhesive temperature about 0 to 30°C higher than the glass transition temperature (Tg) of the adhesive layer is used. Appropriate conditions can be determined taking into account the material of the lead frame or the wettability of the adhesive layer, etc.

[0027] The conditions for bonding the temporary protective film to the lead frame to measure the peel strength after application are not particularly limited, but may be, for example, the conditions for bonding the temporary protective film to the lead frame described below. For example, a copper lead frame, a palladium-coated copper lead frame, or a 42 alloy lead frame may be used as the lead frame, and the film may be bonded under any of the following bonding 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 8 MPa, time 10 seconds.

[0028] In particular, the 90-degree peel strength between the adhesive layer and the lead frame immediately before the encapsulation step may be 5 N / m or more, 10 N / m or more, or 50 N / m or more at 25° C. If the 90-degree peel strength immediately before the encapsulation step is 5 N / m or more at 25° C., problems such as the encapsulating resin getting between the lead frame and the adhesive layer during the encapsulation step tend to be suppressed. Here, "immediately before the encapsulation step" means before the encapsulation step and when all steps to be performed before the encapsulation step have been completed.

[0029] After the temporary protective film is attached or bonded to the lead frame, a heating step may be performed to heat the lead frame with the temporary protective film before the sealing step. This can also improve the adhesive strength between the adhesive layer and the lead frame. The heating temperature in the heating step is not particularly limited, but may be 100°C or higher to improve the adhesive strength between the adhesive layer and the lead frame. The heating temperature may be 400°C or lower in terms of the heat resistance of the lead frame and the temporary protective film. For the same reason, the heating temperature may be 130°C or higher and 350°C or lower. The heating time is not particularly limited, but may be 10 seconds or longer to sufficiently improve the adhesive strength between the adhesive layer and the lead frame. For the same reason, the heating time may be 1 minute or longer and 2 hours or shorter.

[0030] From the viewpoint of productivity, the above heating step may be carried out by heating in various steps before the sealing step (for example, a step of curing an adhesive such as silver paste (a step of adhering a semiconductor element), a reflow connection step, a wire bonding step, etc.). For example, as described above, in the step of adhering a semiconductor element, heating is usually carried out at 140 to 200°C for 30 minutes to 2 hours to cure the adhesive used for adhesion. Therefore, the above heating step can be carried out by heating in these various steps.

[0031] When a temporary protective film is attached to a lead frame so that the adhesive layer is in contact with the lead frame, a semiconductor element is mounted on the surface of the die pad opposite the temporary protective film, and an encapsulating layer is formed that encapsulates the semiconductor element while in contact with the adhesive layer, the 90-degree peel strength between the adhesive layer and the lead frame and encapsulating layer (hereinafter also referred to as "post-encapsulation peel strength") may be 1000 N / m or less, 800 N / m or less, or 500 N / m or less in at least a portion of a temperature range of 0 to 250°C. When the post-encapsulation peel strength is 1000 N / m or less, the problem of breakage when stress is applied to the lead frame and encapsulating layer tends to be suppressed. The post-encapsulation peel strength usually decreases as the measurement temperature increases. The post-encapsulation peel strength may be 0 N / m or more, 3 N / m or more, or 5 N / m or more in at least a portion of a temperature range of 0 to 250°C.

[0032] The peel strength after encapsulation may be in the above-mentioned range in at least a part of the temperature range of 80 to 250°C, and may be in the above-mentioned range at the temperature when the temporary protective film is peeled off from the lead frame and the encapsulating layer.

[0033] The post-encapsulation peel strength is measured in accordance with the 90-degree peel method of JIS Z 0237, by peeling the temporary protective film at a 90-degree angle from the lead frame and encapsulating layer at room temperature or on a stage at 0 to 250°C. Specifically, the 90-degree peel strength is measured using a 90-degree peel tester (manufactured by Testa Sangyo Co., Ltd.) when the temporary protective film is peeled at a speed of 270 to 330 mm per minute or 300 mm per minute in at least a part of the temperature range of 0 to 250°C. The temperature range for measuring this peel strength may be 80 to 240°C or 140 to 230°C.

[0034] The temperature at which the temporary protective film is peeled off from the lead frame and the sealing layer (the temperature of the temporary protective film) may typically be between 0 and 250°C. The sealing conditions using the sealing material for measuring the post-sealing peel strength in at least a portion of the temperature range of 0 to 250°C are not particularly limited, and may be the conditions for forming the sealing layer in the semiconductor device manufacturing method described below. Formation of the sealing layer may include, for example, using CEL-9200 (trade name, biphenyl sealing material manufactured by Hitachi Chemical Co., Ltd.) as the sealing material, forming the sealing layer under conditions of a temperature of 180°C, a pressure of 10 MPa, and a time of 3 minutes, and curing the sealing material forming the sealing layer by heating at 180°C for 5 hours.

[0035] <Adhesive layer> The adhesive layer may contain a resin. The resin used to form the adhesive layer (hereinafter also referred to as "resin (a)") may be a thermoplastic resin having an amide group (-NHCO-), an ester group (-CO-O-), an imide group (-NR2, where R is each -CO-), an ether group (-O-), or a sulfone group (-SO2-). Resin (a) may be a thermoplastic resin having an amide group, an ester group, an imide group, or an ether group. Specific examples of resin (a) include aromatic polyamide, aromatic polyester, aromatic polyimide, aromatic polyamideimide, aromatic polyether, aromatic polyetheramideimide, aromatic polyetheramide, aromatic polyesterimide, and aromatic polyetherimide. From the viewpoint of heat resistance and adhesiveness, resin (a) may be at least one selected from the group consisting of aromatic polyetheramideimide, aromatic polyetherimide, and aromatic polyetheramide.

[0036] Resin (a) can be produced, for example, by polycondensation of a base component such as an aromatic diamine or bisphenol with an acid component such as a dicarboxylic acid, tricarboxylic acid, tetracarboxylic acid, or aromatic chloride, or a reactive derivative thereof. That is, the reaction can be carried out by a conventional method used for the reaction of an amine with an acid, and there are no particular limitations on the conditions, etc. A conventional method is used for the polycondensation reaction of an aromatic dicarboxylic acid, aromatic tricarboxylic acid, or a reactive derivative thereof with a diamine.

[0037] The aromatic polyetherimide, aromatic polyetheramideimide, and aromatic polyetheramide may contain structural units derived from the base component used for synthesizing these polymers. Examples of the base component include aromatic diamines having an ether group such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4'-diaminodiphenyl ether, bis[4-(4-aminophenoxy)phenyl]ether, and 2,2-bis[4-(4-aminophenoxy)]hexafluoropropane; aromatic diamines not having an ether group 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. Based on the total amount of the base component, the proportion of the aromatic diamine having an ether group may be 40 to 100 mol %, or 50 to 97 mol %, and the proportion of at least one selected from the aromatic diamine having no ether group, siloxane diamine, and α,ω-diaminoalkane may be 0 to 60 mol %, or 3 to 50 mol %. Examples of combinations of base components include: (1) a combination of base components consisting of 60 to 89 mol % or 68 to 82 mol % of an aromatic diamine having an ether group, 1 to 10 mol % or 3 to 7 mol % of a siloxane diamine, and 10 to 30 mol % or 15 to 25 mol % of an α,ω-diaminoalkane; (2) a combination of base components consisting of 90 to 99 mol % or 93 to 97 mol % of an aromatic diamine having an ether group and 1 to 10 mol % or 3 to 7 mol % of a siloxane diamine; and (3) a combination of base components consisting of 40 to 70 mol % or 45 to 60 mol % of an aromatic diamine having an ether group and 30 to 60 mol % or 40 to 55 mol % of an aromatic diamine not having an ether group.

[0038] Aromatic polyetherimides, aromatic polyetheramideimides, and aromatic polyetheramides may contain structural units derived from the acid components used in the synthesis of these polymers. Examples of acid components include (A) reactive derivatives of trimellitic anhydride, such as trimellitic anhydride and trimellitic anhydride chloride, mononuclear aromatic tricarboxylic anhydrides or mononuclear aromatic tetracarboxylic dianhydrides, such as pyromellitic dianhydride, (B) polynuclear aromatic tetracarboxylic dianhydrides, such as bisphenol A bistrimellitate dianhydride and oxydiphthalic anhydride, and (C) aromatic dicarboxylic acids, such as reactive derivatives of phthalic acid, such as terephthalic acid, isophthalic acid, terephthalic acid chloride, and isophthalic acid chloride. The aromatic polyetheramide may be obtained, for example, by reacting 0.95 to 1.05 moles or 0.98 to 1.02 moles of the acid component (A) with 1 mole of the base component (1) or (2). The aromatic polyetherimide may be obtained by reacting, for example, 0.95 to 1.05 mol, or 0.98 to 1.02 mol, of the acid component (B) with 1 mol of the above-mentioned base component (3).

[0039] The adhesive layer may contain fillers such as ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles, coupling agents, etc. When the adhesive layer contains a filler, the content of the filler may be 1 to 30 parts by weight, or 5 to 15 parts by weight, per 100 parts by weight of the resin (a).

[0040] The coupling agent may be, for example, vinyl silane, epoxy silane, mercapto silane, titanate, aluminum chelate, zircoaluminate, or a combination thereof. The coupling agent may be a silane coupling agent. Examples of silane coupling agents include vinyl trimethoxy silane, vinyl triethoxy silane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, 3-glycidoxypropyl trimethoxy silane, 3-glycidoxypropyl methyl diethoxy silane, 3-glycidoxypropyl triethoxy silane, 3-methacryloxypropyl trimethoxy silane, and 3-mercaptopropyl trimethoxy silane. The silane coupling agent may be an epoxy silane coupling agent having an epoxy group. When the adhesive layer contains a silane coupling agent, the adhesion of the adhesive layer to the support film can be improved, thereby making it less likely for peeling to occur at the interface between the adhesive layer and the support film when the temporary protective film is peeled off. The content of the coupling agent may be 1 to 15 parts by weight, or 2 to 10 parts by weight, based on 100 parts by weight of the resin (a).

[0041] From the viewpoint of adhesion and heat resistance, the glass transition temperature of the adhesive layer may be 100 to 300°C, 130 to 280°C, or 150 to 250°C. If the glass transition temperature is 100°C or higher, peeling is unlikely to occur at the interface between the adhesive layer and the support film when the temporary protective film is peeled off from the lead frame and the encapsulant, and the adhesive layer tends to be less susceptible to cohesive failure. Furthermore, in the wire bonding process, the adhesive layer does not soften too much, which suppresses dispersion of force during wire connection and tends to reduce the likelihood of wire connection failure. If the glass transition temperature is 300°C or lower, the adhesive layer softens sufficiently during bonding, which tends to suppress a decrease in the 90-degree peel strength between the adhesive layer and the lead frame at 25°C. Therefore, peeling during the transport process and leakage of the encapsulant during sealing are less likely to occur.

[0042] The 5% weight loss temperature of the adhesive layer may be 300°C or higher, 350°C or higher, or 400°C or higher. When the 5% weight loss temperature of the adhesive layer is 300°C or higher, outgassing due to the heat generated when attaching the temporary protective film to the lead frame and / or the heat generated during the wire bonding process is less likely to occur, and the lead frame and wires tend to be less likely to be contaminated. The 5% weight loss temperature of the adhesive layer can be determined by measuring the temperature at a heating rate of 10°C / min using a differential thermobalance (TG / DTA220, manufactured by Seiko Instruments Inc.).

[0043] The adhesive layer may have a modulus of elasticity at 230°C of 1 MPa or more, or 3 MPa or more. The wire bonding temperature is not particularly limited, but is generally about 180 to 260°C, often around 230°C. Therefore, if the modulus of elasticity at 230°C is 1 MPa or more, the adhesive layer does not soften excessively due to the heat during the wire bonding process, and poor wire bonding tends to be less likely to occur. The upper limit of the adhesive layer's modulus of elasticity at 230°C is not particularly limited, but may be 2000 MPa or less, 1500 MPa or less, or 1000 MPa or less. The adhesive layer's modulus of elasticity at 230°C is measured in a dynamic viscoelasticity measuring device (Rheogel-E4000, manufactured by UBM Corporation) set with a chuck distance of 20 mm, using a sine wave, a heating rate of 5°C / min, and a frequency of 10 Hz in tension mode.

[0044] The thickness (A) of the adhesive layer may be 1 to 20 μm, 3 to 15 μm, or 4 to 10 μm. When the thickness (A) of the adhesive layer is 1 μm or more, the adhesiveness is excellent and the sealing material tends to be less likely to leak during sealing. When the thickness (A) of the adhesive layer is 20 μm or less, the cost efficiency tends to be excellent.

[0045] <Support film> The support film is not particularly limited, and may be a film containing a resin (heat-resistant resin) that can withstand the heat during the coating and drying of the resin used to form the adhesive layer or non-adhesive layer and the semiconductor device assembly process. The support film may be, for example, a film of at least one polymer selected from the group consisting of aromatic polyimide, aromatic polyamide, aromatic polyamideimide, aromatic polysulfone, aromatic polyethersulfone, polyphenylene sulfide, aromatic polyetherketone, polyarylate, aromatic polyetheretherketone, and polyethylene naphthalate, i.e., a film containing the polymer.

[0046] The glass transition temperature of the support film may be 200° C. or higher, or 250° C. or higher, in order to improve heat resistance. By using a film of the above polymer, the support film does not soften in steps where heat is applied, such as a step of adhering a semiconductor element to a die pad, a wire bonding step, an encapsulation step, and a step of peeling off a temporary protective film from an encapsulated molded body, and operations can be performed efficiently.

[0047] To reduce the warpage of the lead frame after the temporary protective film is attached to the lead frame, the linear expansion coefficient of the support film at 20 to 200°C is set to 3.0 × 10 -5 / ℃ or less, 2.5×10 -5 / ℃ or less, or 2.0×10 -5 / °C or less. The linear expansion coefficient of the support film at 20 to 200°C is measured in accordance with JIS K 7197. A thermomechanical analyzer (TMA) is used for the measurement. The distance between chucks is set to 20 mm, and the thermal expansion coefficient at 20 to 200°C is calculated.

[0048] In order to reduce warpage of the lead frame after the temporary protective film is attached to the lead frame, the heat shrinkage rate when the support film is heated at 200°C for 2 hours may be 0.15% or less, 0.13% or less, or 0.10% or less. The heat shrinkage rate can be measured in accordance with JIS K 7133. A universal measuring microscope MF-U manufactured by Mitutoyo Corporation is used for the heat shrinkage rate measurement. The heat shrinkage rate can be determined by measuring the difference in the dimension of the support film in the MD direction (longitudinal 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 2 hours. The heat shrinkage rate is measured in the larger of the MD and TD directions.

[0049] The support film may have sufficiently high adhesion to the adhesive layer. If the adhesion is high, when the temporary protective film is peeled off from the lead frame and the sealing material at a temperature of 100 to 300°C, peeling is unlikely to occur at the interface between the adhesive layer and the support film, and resin is unlikely to remain on the lead frame and the sealing material. The support film may be a polyimide film from the viewpoints of heat resistance and adhesion to the adhesive layer.

[0050] The support film may be surface-treated to sufficiently enhance adhesion to the adhesive layer. The surface treatment method for the support film is not particularly limited, but examples thereof include chemical treatments such as alkali treatment and silane coupling treatment, physical treatments such as sand mat treatment, plasma treatment, and corona treatment.

[0051] The thickness of the support film is not particularly limited, but may be 5 to 100 μm, or 5 to 50 μm or less. When the thickness of the support film is 5 μm or more, the temporary protective film is less likely to wrinkle, which tends to improve workability. When the thickness of the support film is 100 μm or less, warping of the lead frame after the temporary protective film is attached to the lead frame tends to be more easily suppressed.

[0052] The support film may be made of a metal selected from the group consisting of copper, aluminum, stainless steel, and nickel. When the support film contains one of these metals, the linear expansion coefficients of the lead frame and the support film become similar, thereby reducing warpage of the lead frame after the temporary protective film is attached to the lead frame.

[0053] The ratio T2 / T1 of the thickness T2 of the adhesive layer to the thickness T1 of the support film may be 0.5 or less, 0.3 or less, or 0.2 or less. When T2 / T1 is 0.5 or less, curling of the film due to a decrease in the volume of the adhesive layer when the solvent is removed after coating is suppressed, and workability when attaching the film to a lead frame tends to be improved.

[0054] <Non-adhesive layer> The non-adhesive layer is a resin layer that has substantially no adhesiveness (or pressure-sensitive adhesiveness) to the lead frame at 0 to 270° C. Providing the non-adhesive layer in the temporary protective film can offset curling of the temporary protective film caused by a volumetric decrease in the adhesive layer when the solvent is removed, or a volumetric decrease in the adhesive layer due to shrinkage during imidization or curing of the thermosetting resin.

[0055] The non-adhesive layer may be a resin layer that does not easily soften at high temperatures, and for example, a resin layer having a high glass transition temperature can function as the non-adhesive layer.

[0056] The non-adhesive layer may contain a resin. The composition of the resin (hereinafter also referred to as "resin (b)") used to form the non-adhesive layer is not particularly limited, and may be either a thermoplastic resin or a thermosetting resin. The thermoplastic resin is not particularly limited, and may be a thermoplastic resin having at least one functional group selected from the group consisting of an amide group, an ester group, an imide group, an ether group, and a sulfone group. The thermosetting resin is not particularly limited, and may be, for example, an epoxy resin, a phenolic resin, a bismaleimide resin (e.g., a bismaleimide resin having bis(4-maleimidophenyl)methane as a monomer), or the like. A thermoplastic resin and a thermosetting resin may be combined. When a thermoplastic resin and a thermosetting resin are combined, the amount of the thermosetting resin may be 5 to 100 parts by mass or 20 to 70 parts by mass per 100 parts by mass of the thermoplastic resin.

[0057] The non-adhesive layer may contain a filler such as ceramic powder, glass powder, silver powder, copper powder, resin particles, rubber particles, etc., a coupling agent, etc. When the non-adhesive layer contains a filler, the content of the filler may be 1 to 30 parts by mass, or may be 5 to 15 parts by mass, per 100 parts by mass of the resin (b). The content of the coupling agent may be 1 to 20 parts by mass, or may be 2 to 15 parts by mass, per 100 parts by mass of the resin (b).

[0058] The elastic modulus of the non-adhesive layer at 230°C may be 10 MPa or more, 100 MPa or more, or 1000 MPa or more. If the elastic modulus of the non-adhesive layer at 230°C is 10 MPa or more, it tends to be difficult to soften during processes that involve heat, such as wire bonding processes, and therefore difficult to adhere to molds and jigs. The elastic modulus of the non-adhesive layer at 230°C may be 2000 MPa or less, or 1500 MPa or less.

[0059] The elastic modulus of the non-adhesive layer at 230°C can be measured using a dynamic viscoelasticity measuring device (Rheogel-E4000, manufactured by UBM Corporation) set with a chuck distance of 20 mm, using a sine wave, a temperature rise rate of 5°C / min, and a frequency of 10 Hz in tension mode.

[0060] The adhesive strength of the non-adhesive layer to the mold and jig is not particularly limited as long as it is low enough not to stick to the mold and / or jig in the process, but the 90-degree peel strength between the non-adhesive layer and the mold and jig at 25° C. may be less than 5 N / m or less than 1 N / m. This peel strength is measured, for example, after pressing the non-adhesive layer against a brass mold at a temperature of 250° C. and a pressure of 8 MPa for 10 seconds.

[0061] The glass transition temperature of the non-adhesive layer may be 150°C or higher, 200°C or higher, or 250°C or higher so that the non-adhesive layer is less likely to soften and less likely to stick to a mold or jig during processes such as bonding a semiconductor element to a die pad, a wire bonding process, a sealing process, and a process of peeling a temporary protective film from the sealed molded body. The glass transition temperature of the non-adhesive layer may be 350°C or lower, or 300°C or lower.

[0062] The thickness of the non-adhesive layer is, for example, 10 μm or less, and may be 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, and may be, for example, 1 to 10 μm or 1 to 8 μm.

[0063] The surface roughness Ra of the surface opposite to the surface in contact with the support film of the non-adhesive layer is 0.1 μm, and may be 0.15 μm or more, or 0.2 μm or more. The surface roughness Ra here is a value measured using a laser microscope with an objective lens at a magnification of 50x. The surface roughness Ra is determined, for example, by analyzing an image obtained by joining together images of 11 vertical and 9 horizontal sections. When the surface roughness Ra is 0.1 μm or more, the non-adhesive layer exhibits excellent sliding properties with the stage inside the device, reducing jamming problems. Furthermore, the non-adhesive layer exhibits excellent sliding properties with lead frames to which the temporary protective film is attached, reducing the likelihood of sticking and inseparable problems. The surface roughness Ra can be measured using a laser microscope, such as the VK-X100 shape measuring laser microscope manufactured by Keyence Corporation. The surface roughness (Ra) of the surface opposite to the surface in contact with the support film of the non-adhesive layer may be, for example, 3 μm or less, 2 μm or less, or 1 μm or less. From the same viewpoint as above, the surface roughness Ra of the surface of the non-adhesive layer opposite to the surface in contact with the support film may be 0.4 μm or more, 0.5 μm or more, or 0.6 μm or more, and may be 8 μm or less, or 6 μm or less, when measured using a laser microscope with an objective lens magnification of 10x.

[0064] <Method of manufacturing temporary protective film> A temporary protective film according to one embodiment includes, for example, dissolving the resin (a) used to form the adhesive layer in a solvent such as N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, or dimethylformamide to prepare an adhesive varnish; applying the adhesive varnish to one side of a support film; and removing the solvent from the applied adhesive varnish by heating to form an adhesive layer. This method can produce a two-layer temporary protective film. The method for forming the temporary protective film may also include preparing a precursor varnish by dissolving a resin (a) precursor (e.g., a polyamic acid) in a solvent, which generates the resin (a) (e.g., a polyimide resin) by heat treatment or the like; applying the precursor varnish to one side of the support film; and heat-treating the applied precursor varnish to form an adhesive layer containing the resin (a). This method can also produce a two-layer temporary protective film. When a resin (a) precursor is used, the solvent is removed by heat treatment after application, and the resin (a) is generated from the precursor by, for example, imidization. In view of the surface condition of the coated surface, an adhesive varnish may be used.

[0065] When the support film coated with the above-mentioned varnish is heat-treated to remove the solvent, imidize, etc., the heat treatment temperature may differ depending on whether an adhesive varnish or a precursor varnish is used. In the case of an adhesive varnish, the temperature may be a temperature at which the solvent can be removed, and in the case of a precursor varnish, the treatment temperature may be a temperature equal to or higher than the glass transition temperature of the adhesive layer to effect imidization.

[0066] The method for applying the adhesive varnish or precursor varnish to one side of the support film is not particularly limited. For example, the varnish can be applied using roll coating, reverse roll coating, gravure coating, bar coating, or comma coating. The varnish may also be applied by passing the support film through the adhesive varnish or precursor varnish.

[0067] The method for forming the non-adhesive layer is not particularly limited, but includes, for example, dissolving resin (b) in a solvent such as N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, or dimethylformamide to prepare a resin varnish, applying the resin varnish to a support film, and removing the solvent from the applied resin varnish by heating. The method for forming the non-adhesive layer may also include dissolving a resin (b) precursor (e.g., polyamic acid) in a solvent to prepare a precursor varnish, which generates resin (b) (e.g., a polyimide resin) by heating, applying the precursor varnish to a support film, and heating the applied precursor varnish. In this case, the solvent is removed by heat treatment after application, and resin (b) is generated from the precursor by, for example, imidization. Resin varnish may be used in consideration of the surface condition of the coating film.

[0068] When the support film coated with the above-mentioned varnish is heat-treated to remove the solvent, imidize, etc., the heat treatment temperature may differ depending on whether a resin varnish or a precursor varnish is used. When a resin varnish is used, the temperature may be such that the solvent can be removed, and when a precursor varnish is used, the treatment temperature may be equal to or higher than the glass transition temperature of the non-adhesive layer to effect imidization.

[0069] There are no particular limitations on the method for applying the resin varnish or precursor varnish of resin (b) to the support film. For example, the varnish can be applied using roll coating, reverse roll coating, gravure coating, bar coating, comma coating, etc. The varnish may also be applied by passing the support film through the resin varnish or precursor varnish.

[0070] <Method of manufacturing a semiconductor device> A semiconductor device can be manufactured by a method including a step of encapsulating a semiconductor element using a temporary protective film according to one embodiment. The semiconductor device is manufactured by peeling off the temporary protective film from a semiconductor device having the temporary protective film, the semiconductor element attached to the die pad of the lead frame, a conductive material such as a wire or metal plate connecting the semiconductor element to the inner lead of the lead frame, and an encapsulation layer encapsulating the exposed surface of the lead frame, the semiconductor element, and the wire.

[0071] The semiconductor device to be manufactured may be, for example, a non-lead type package having a lead frame, a semiconductor element mounted on the lead frame, and an encapsulation layer that encapsulates the semiconductor element on the semiconductor element side of the lead frame, with the back surface of the lead frame exposed for external connection. Specific examples include QFN (Quad Flat Non-leaded Package) and SON (Small Outline Non-leaded Package).

[0072] Figures 2 and 3 are cross-sectional views showing a method for manufacturing a semiconductor device according to one embodiment. Figure 4 is a cross-sectional view showing one embodiment of a semiconductor device obtained by the manufacturing method shown in Figures 2 and 3. Each step will be described below with reference to the drawings as necessary.

[0073] The manufacturing method of the semiconductor device according to the embodiment includes the steps of, in this order, attaching a temporary protective film 10 to one side (back side) of a lead frame 11 having a die pad 11a and an inner lead 11b, with the adhesive layer facing the lead frame; mounting (adhering) a semiconductor element 14 on the side of the die pad 11a opposite the temporary protective film 10; providing wires 12 connecting the semiconductor element 14 and the inner lead 11b; forming an encapsulating layer 13 that encapsulates the semiconductor element 14 and the wires 12 to obtain an encapsulated molded body 20 having the lead frame 11, the semiconductor element 14, and the encapsulating layer 13; and peeling the temporary protective film 10 from the encapsulated molded body 20.

[0074] The temporary protective film 10 may be attached to the lead frame 11 under heating or at room temperature (for example, 5 to 35°C). The attachment method is not particularly limited, and may be, for example, a roll lamination method. A lead frame with a temporary protective film according to one embodiment includes a lead frame 11 having a die pad 11a and inner leads 11b, and the temporary protective film 10. The temporary protective film 10 is attached to the lead frame 11 so that its adhesive layer 2 contacts one side of the lead frame 11.

[0075] There are no particular restrictions on the conditions for bonding the temporary protective film 10 to the lead frame 11, but the bonding temperature may be 150 to 400°C, 180 to 350°C, or 200 to 300°C. When the bonding temperature is 150°C or higher, the adhesive strength between the lead frame 11 and the adhesive layer 2 tends to be further improved. When the bonding temperature is 400°C or lower, deterioration of the lead frame 11 tends to be further suppressed.

[0076] The adhesive pressure of the temporary protective film 10 to the lead frame 11 may be 0.5 to 30 MPa, 1 to 20 MPa, or 3 to 15 MPa. When the adhesive pressure is 0.5 MPa or more, the adhesive strength between the adhesive layer 2 and the lead frame 11 tends to be further improved. When the adhesive pressure is 30 MPa or less, damage to the lead frame 11 tends to be more easily suppressed.

[0077] The time for adhering the temporary protective film 10 to the lead frame 11 may be 0.1 to 60 seconds, 1 to 30 seconds, or 3 to 20 seconds. When the adhering time is 0.1 seconds or more, the adhesive strength between the adhesive layer 2 and the lead frame 11 tends to be more easily improved. When the adhering time is 60 seconds or less, the workability and productivity tend to be more easily improved. Before applying pressure, preheating may be performed for about 5 to 60 seconds.

[0078] The material of the lead frame 11 is not particularly limited, but may be, for example, an iron-based alloy such as alloy 42, copper, or a copper-based alloy. When copper or a copper-based alloy is used, the surface of the lead frame may be coated with palladium, gold, silver, or the like.

[0079] The semiconductor element 14 is usually mounted (bonded) to the die pad 11a via an adhesive (for example, silver paste). The adhesive may be hardened by heat treatment (for example, at 140 to 200° C. for 30 minutes to 2 hours).

[0080] After mounting (bonding) the semiconductor element, the semiconductor element and the inner leads may be connected by solder reflow using a conductive material such as a copper plate. That is, the method for manufacturing a semiconductor device may further include a step of connecting the semiconductor element mounted on the die pad and the inner leads with a conductive material by reflow. The connection by reflow may be performed, for example, at a maximum temperature in the range of 250 to 420°C for 1 to 30 minutes. The connection by reflow is performed, for example, before the step of obtaining the encapsulated molded body 20 and after the step of mounting (bonding) the semiconductor element 14. The connection by reflow may be performed, for example, after the step of mounting (bonding) the semiconductor element 14 and before the step of providing the wire 12.

[0081] There are no particular limitations on the wire 12, and it may be, for example, a gold wire, a copper wire, a palladium-coated copper wire, or an aluminum wire. For example, the semiconductor element and the inner lead may be bonded to the wire 12 by heating at 200 to 300°C for 3 minutes to 3 hours.

[0082] In the encapsulation molding process, an encapsulating layer 13 is formed using an encapsulating material. The encapsulation molding produces an encapsulated molded body 20 having a plurality of semiconductor elements 14 and an encapsulating layer 13 that encapsulates them collectively. During the encapsulation molding, the temporary protective film 10 is provided, thereby preventing the encapsulating material from creeping around to the back side of the lead frame 11.

[0083] An sealed molded product with a temporary protective film according to one embodiment includes a lead frame 11 having a die pad 11a and inner leads 11b, a semiconductor element 14 mounted on the die pad 11a, wires 12 connecting the semiconductor element 14 and the inner leads 11b, a sealing layer 13 sealing the semiconductor element 14 and the wires 12, and a temporary protective film 10. The adhesive layer 2 of the temporary protective film 10 is attached to the surface of the lead frame 11 opposite to the surface on which the semiconductor element 14 is mounted.

[0084] The temperature during formation of the sealing layer 13 (sealing temperature) may be, for example, 150 to 200° C. The pressure during formation of the sealing layer (sealing pressure) may be 6 to 15 MPa, or 7 to 10 MPa. The heating time during sealing molding (sealing time) may be 1 to 5 minutes, or 2 to 3 minutes.

[0085] The formed sealing layer 13 may be heat-cured as needed. The heating temperature for curing the sealing layer 13 (sealing curing temperature) may be 150 to 200° C. The heating time for curing the sealing layer 13 (sealing curing time) may be, for example, 4 to 6 hours.

[0086] The encapsulant is not particularly limited, and may be, for example, a curable resin composition containing an epoxy resin such as cresol novolac epoxy resin, phenol novolac epoxy resin, biphenyl diepoxy resin, naphthol novolac epoxy resin, etc. The encapsulant may also contain additives such as a filler, a flame retardant substance such as a bromine compound, and a wax component.

[0087] After the formation of the sealing layer 13 (sealing molding), the temporary protective film 10 is peeled off from the lead frame 11 and the sealing layer 13 of the obtained sealed molded body 20. When the sealing layer is cured, the temporary protective film 10 may be peeled off either before or after the sealing layer 13 is cured.

[0088] The temperature at which the temporary protective film 10 is peeled off from the encapsulated molded body (peeling temperature) may be between 0 and 250°C. When the peeling temperature is 0°C or higher, the adhesive layer is less likely to remain on the lead frame 11 and the encapsulating layer 13. When the peeling temperature is 250°C or lower, deterioration of the lead frame 11 and the encapsulating layer 13 tends to be more easily suppressed. For the same reason, the peeling temperature may be 80 to 240°C, or 140 to 230°C.

[0089] The method for manufacturing a semiconductor device may further include, as necessary, a step of removing the adhesive layer (glue residue) remaining on the lead frame 11 and the sealing layer 13 after the peeling step. When the temporary protective film 10 is peeled off at 0 to 250°C after sealing with the sealing material, no adhesive layer 2 may remain on the lead frame 11 and the sealing layer 13. If a large amount of adhesive layer remains, not only will the appearance be poor, but if the lead frame 11 is used for external connection, it may easily cause poor contact. Therefore, the adhesive layer remaining on the lead frame 11 and the sealing layer 13 may be removed by mechanical brushing, a solvent, or the like. The solvent is not particularly limited, but may be, for example, N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycol dimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone, dimethylformamide, or a combination thereof.

[0090] When the lead frame includes multiple patterns having die pads and inner leads, the encapsulated molded body 20 can be divided as needed to obtain multiple semiconductor devices 100 of Figure 4, each having one semiconductor element.

[0091] That is, when the lead frame 11 has multiple die pads 11a and a semiconductor element 14 is mounted on each of the multiple die pads 11a, the manufacturing method of one embodiment may further include a step of dividing the encapsulated body 20 before or after peeling the temporary protective film 10 from the encapsulated body 20 to obtain a semiconductor device 100 having one die pad 11a and a semiconductor element 14.

[0092] The semiconductor device may be manufactured by winding a long temporary protective film around a core and unwinding the temporary protective film from the resulting reel body. In this case, the reel body has a core and the temporary protective film according to the above embodiment wound around the core.

[0093] 6 is a perspective view showing one embodiment of a reel body 30. The reel body 30 shown in FIG. 6 includes a winding core 31, a temporary protective film 10 wound around the winding core 31, and a side plate 32.

[0094] The width (length in the direction perpendicular to the winding direction) of the winding core 31 and the temporary protective film 10 may be, for example, 10 mm or more, 40 mm or more, 60 mm or more, or 80 mm or more, or 350 mm or less. The width (length in the direction perpendicular to the winding direction) of the winding core 31 and the temporary protective film 10 may be, for example, 10 mm or more and 350 mm or less, 40 mm or more and 350 mm or less, or 80 mm or more and 350 mm or less.

[0095] 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 the reel body 30 and a packaging bag 40 that houses the reel body 30. The reel body 30 is usually housed individually in a packaging bag, but multiple reels 30 (for example, two or three) may be housed in one packaging bag 40.

[0096] The packaging bag 40 may be made of a resin film or a composite film, which is a resin film having an aluminum layer. Specific examples of the packaging bag 40 include aluminum-coated plastic bags. Resin film materials include plastics such as polyethylene, polyester, vinyl chloride, and polyethylene terephthalate. The reel body 30 may be housed in the packaging bag in a vacuum-packed state, for example. The packaging body 50 is not limited to being vacuum-packed.

[0097] Packaging bag 40 may contain a desiccant together with reel body 30. Examples of the desiccant include silica gel. Packaging body 50 may be obtained by further wrapping packaging bag 40 containing reel body 30 in a cushioning material.

[0098] The packaging body 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 the packaging body 50 and a packaging box 60 that houses the packaging body 50. One or more packaging bodies 50 are housed in the packaging box 60. The packaging box 60 can be made of, for example, cardboard.

[0099] A semiconductor device manufactured using a temporary protective film according to one embodiment is superior in terms of high density, small area, thinness, etc., and can be suitably used in electronic devices such as mobile phones, smartphones, personal computers, and tablets. [Example]

[0100] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0101] 1. Preparation of varnish for forming adhesive or non-adhesive layers Varnish A-1 (varnish for forming adhesive layer) A 5-liter four-neck flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionating column was charged with 270.9 g (0.66 mol) of 2,2-bis[-(4-aminophenoxy)phenyl]propane and 8.7 g (0.035 mol) of 1,3-bis(3-aminopropyl)-tetramethyldisiloxane under a nitrogen atmosphere, and then dissolved in 1950 g of N-methyl-2-pyrrolidone. The solution was cooled to 0°C, and 149.5 g (0.71 mol) of trimellitic anhydride chloride was added to the solution at this temperature. After the trimellitic anhydride chloride was dissolved, 100 g of triethylamine was added to the solution. Stirring was continued for 2 hours at room temperature, followed by heating to 180°C and a 5-hour reaction to complete the imidization. The reaction solution was then poured into methanol to precipitate a polymer. The precipitated polymer was dried and then dissolved in N-methyl-2-pyrrolidone. The solution was poured into methanol to precipitate a polymer again. The precipitated polymer was dried under reduced pressure to obtain a purified powdery polyetheramideimide. 120 g of the obtained polyetheramideimide and 3.6 g of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: SH6040) were dissolved in 360 g of N-methyl-2-pyrrolidone to obtain a varnish A-1 containing aromatic polyetheramideimide.

[0102] Varnish A-2 (varnish for forming adhesive layer) A 5-liter four-neck flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionating column was charged with 258.6 g (0.63 mol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 67.0 g (0.27 mol) of 1,3-bis(3-aminopropyl)tetramethyldisiloxane under a nitrogen atmosphere, and this was dissolved in 1550 g of N-methyl-2-pyrrolidone. The solution was then cooled to 0°C, and 187.3 g (0.89 mol) of trimellitic anhydride chloride was added to the solution at this temperature. After the trimellitic anhydride chloride had dissolved, 100 g of triethylamine was added to the solution. Stirring was continued for 2 hours at room temperature, followed by heating to 180°C and a 5-hour reaction to complete the imidization. The reaction solution was then poured into methanol to precipitate a polymer. The precipitated polymer was dried and then dissolved in N-methyl-2-pyrrolidone. The solution was then poured into methanol to precipitate a polymer again. The precipitated polymer was dried under reduced pressure to obtain a purified powdery polyetheramideimide. 120 g of the obtained polyetheramideimide and 3.6 g of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: SH6040) were dissolved in 360 g of N-methyl-2-pyrrolidone to obtain a varnish A-2 containing aromatic polyetheramideimide.

[0103] Varnish B-1 (varnish for forming a non-adhesive layer) A 5-liter four-neck flask equipped with a thermometer, stirrer, nitrogen inlet tube, and fractionating column was charged with 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) under a nitrogen atmosphere, and dissolved in 1550 g of N-methyl-2-pyrrolidone. The solution was then cooled to 0°C, and 174.7 g (0.83 mol) of trimellitic anhydride chloride was added to the solution at this temperature. After the trimellitic anhydride chloride had dissolved, 130 g of triethylamine was added to the solution. Stirring was continued for 2 hours at room temperature, followed by heating to 180°C and a 5-hour reaction to complete the imidization. The reaction solution was then poured into methanol to precipitate a polymer. The precipitated polymer was dried and then dissolved in N-methyl-2-pyrrolidone. The solution was poured into methanol to precipitate a polymer again. The precipitated polymer was dried under reduced pressure to obtain a purified powdery polyetheramideimide. 120 g of the obtained polyetheramideimide and 6 g of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: SH6040) were dissolved in 360 g of N-methyl-2-pyrrolidone to obtain a varnish B-1 containing aromatic polyetheramideimide.

[0104] Varnish B-2 (varnish for forming a non-adhesive layer) 40 g of the polyetheramideimide synthesized in Production Example 3 and 2 g of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: SH6040) were dissolved in 500 g of N-methyl-2-pyrrolidone to obtain a varnish B-2 containing aromatic polyetheramideimide.

[0105] 2. Preparation and evaluation of temporary protective film Surface roughness Ra measurement method Using a shape measuring laser microscope VK-X100 manufactured by Keyence Corporation, the surface roughness Ra of the surface opposite to the surface in contact with the support film of the non-adhesive layer (the back surface of the temporary protective film) was measured under the following conditions 1 or 2. Condition 1: Objective lens magnification 50x, laser wavelength 658nm Condition 2: Objective lens magnification 10x, laser wavelength 658nm

[0106] Example 1 A 25 μm-thick polyimide film (Kapton 100EN, manufactured by DuPont-Toray Co., Ltd.) was used as a support film. Varnish A-1 was cast to a thickness of 25 μm on one side of this polyimide film. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to obtain a temporary protective film with a 3 μm-thick adhesive layer on one side of the support film. The adhesive layer had a glass transition temperature of 230°C, a 5% weight loss temperature of 451°C, and an elastic modulus at 230°C of 150 MPa. Furthermore, varnish B-1 was cast to a thickness of 20 μm on the side of the polyimide film opposite the adhesive layer. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to form a 2 μm-thick non-adhesive layer. This non-adhesive layer had a glass transition temperature of 260°C, a 5% weight loss temperature of 421°C, and an elastic modulus of 1700 MPa at 230°C. As a result, a temporary protective film of Example 1 was obtained, in which an adhesive layer was provided on one side of the support film and a non-adhesive layer was provided on the other side, as shown in Figure 1. The ratio of the thickness (A) of the adhesive layer to the thickness (C) of the support film was 0.12. In the temporary protective film of Example 1, the surface roughness (Ra) of the surface of the non-adhesive layer opposite to the surface in contact with the support film (the back surface of the temporary protective film) was 0.26 μm under condition 1 and 0.6 μm under condition 2.

[0107] The temporary protective film of Example 1 was adhered to a palladium-coated copper lead frame (50 mm x 200 mm) at a temperature of 250°C, a pressure of 8 MPa, and a time of 10 seconds. The 90-degree peel strength (peel rate: 300 mm per minute, same below) between the adhesive layer and the lead frame at 25°C was measured, and it was 50 N / m, with no peeling problems during transportation. There was almost no curling of the temporary protective film, and workability during adhesion was good.

[0108] The warpage of the temporary protective film of Example 1 was measured. Fig. 5 is a schematic diagram showing a method for evaluating warpage. As shown in Fig. 5, a lead frame with a temporary protective film, in which a temporary protective film 10 was attached to a lead frame 11, was placed on a base 200, and the warpage (X) in the longitudinal direction of this lead frame with a temporary protective film was measured. As a result of measuring the warpage (X) of the temporary protective film of Example 1, the warpage (X) was about 0.1 mm.

[0109] The resulting lead frame with the temporary protective film was used to bond the semiconductor element, perform the wire bonding process, and perform the encapsulation process. No problems, such as stoppages due to lead frame transport issues, were observed in any of the processes. The resulting package had the structure shown in Figure 3. Silver paste was used to bond the semiconductor element, and the silver paste was cured by heating at 150°C for 60 minutes. Gold wire was used as the wire for wire bonding, and the process was performed by heating at 260°C for 5 minutes. Biphenyl encapsulant (Hitachi Chemical Co., Ltd., product name: CEL9200) was used as the encapsulant for the encapsulation process. The encapsulation layer was formed at 180°C, 10 MPa, and for 3 minutes, and then cured by heating at 180°C for 5 hours. No problems were observed in any of the processes. After the encapsulation process, the temporary protective film was peeled off from the lead frame and encapsulant at 200°C. The 90-degree peel strength was 150 N / m, and the peeling was easy. There was almost no resin residue on the lead frame or encapsulation resin. Even the small amount of residual resin could be removed by washing with N-methyl-2-pyrrolidone. This package was then divided into separate packages, each containing a single semiconductor element, as shown in Figure 4. No problems were observed during this process.

[0110] Example 2 A 25 μm-thick polyimide film (Ube Industries, Ltd., Upilex SPA) was used as the support film. Varnish A-1 was cast to a thickness of 40 μm on one side of this polyimide film. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to obtain a temporary protective film with a 6 μm-thick adhesive layer on one side of the support film. The adhesive layer had a glass transition temperature of 230°C, a 5% weight loss temperature of 451°C, and an elastic modulus at 230°C of 150 MPa. Furthermore, varnish B-2 was cast to a thickness of 100 μm on the side of the polyimide film opposite the adhesive layer. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to form a 5 μm-thick non-adhesive layer. This non-adhesive layer had a glass transition temperature of 260°C, a 5% weight loss temperature of 421°C, and an elastic modulus of 1700 MPa at 230°C. As a result, a temporary protective film of Example 2 was obtained, in which an adhesive layer was provided on one side of the support film and a non-adhesive layer was provided on the other side, as shown in Figure 1. The ratio of the thickness (A) of the adhesive layer to the thickness (C) of the support film was 0.24. In the temporary protective film of Example 2, the surface roughness (Ra) of the surface of the non-adhesive layer opposite to the surface in contact with the support film (the back surface of the temporary protective film) was 0.22 μm under condition 1 and 0.8 μm under condition 2.

[0111] Example 3 A 25 μm thick polyimide film (Ube Industries, Ltd., Upilex SGA) was used as the support film. Varnish A-1 was cast to a thickness of 60 μm on one side of this polyimide film and dried at 100 ° C for 10 minutes and then at 300 ° C for 10 minutes to obtain a temporary protective film with a 9 μm thick adhesive layer on one side of the support film. The adhesive layer had a glass transition temperature of 230 ° C, a 5% weight loss temperature of 451 ° C, and an elastic modulus at 230 ° C of 150 MPa. Furthermore, varnish B-2 for forming the non-adhesive layer produced in Production Example 2 was cast to a thickness of 180 μm on the side of the polyimide film opposite the adhesive layer, and then dried at 100 ° C for 10 minutes and then at 300 ° C for 10 minutes to form a 9 μm thick non-adhesive layer. The glass transition temperature of this non-adhesive layer was 260°C, the 5% weight loss temperature was 421°C, and the elastic modulus at 230°C was 1700 MPa. As a result, a temporary protective film of Example 3 was obtained, in which an adhesive layer was provided on one side of the support film and a non-adhesive layer was provided on the other side, as shown in Figure 1. The ratio of the thickness (A) of the adhesive layer to the thickness (C) of the support film was 0.36. In the temporary protective film of Example 3, the surface roughness (Ra) of the surface of the non-adhesive layer opposite to the surface in contact with the support film (the back surface of the temporary protective film) was 0.67 μm under condition 1 and 1.1 μm under condition 2.

[0112] Comparative Example 1 A 25 μm-thick polyimide film (Ube Industries, Ltd., Upilex SPA) with a plasma-treated surface was used as the support film. Varnish A-2 was cast to a thickness of 50 μm on one side of this polyimide film. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to form a 10 μm-thick adhesive layer. This adhesive layer had a glass transition temperature of 187°C, a 5% weight loss temperature of 429°C, and an elastic modulus at 230°C of 5 MPa. Furthermore, varnish B-1 was cast to a thickness of 50 μm on the opposite side of the polyimide film. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to form a 10 μm-thick non-adhesive layer. This non-adhesive layer had a glass transition temperature of 260°C, a 5% weight loss temperature of 421°C, and an elastic modulus at 230°C of 1700 MPa. This resulted in the temporary protective film of Comparative Example 1, in which an adhesive layer was provided on one side of the support film and a non-adhesive layer was provided on the other side, as shown in Figure 1. In the temporary protective film of Comparative Example 1, the surface roughness (Ra) of the surface opposite to the surface of the non-adhesive layer that contacts the support film (the back surface of the temporary protective film) was 0.05 μm under condition 1 and 0.3 μm under condition 2.

[0113] After bonding to a palladium-coated copper lead frame at a temperature of 250°C, a pressure of 8 MPa, and a time of 10 seconds, the 90-degree peel strength with the lead frame at 25°C was measured to be 150 N / m, and no peeling problems occurred during transportation. There was almost no curling of the temporary protective film, and workability during bonding was good. As in Example 1, the longitudinal warpage (X) of the lead frame was measured to be approximately 0.15 mm. Using the lead frame with this temporary protective film bonded, bonding of semiconductor elements, wire bonding, and sealing processes were performed in the same manner as in Example 1, but transportation problems were observed due to poor sliding between the lead frame and the stage during the lead frame transportation process.

[0114] The temporary protective films of the examples, in which the surface roughness (Ra) of the back surface is 0.1 μm or more under condition 1 and 0.4 μm or more under condition 2, have high adhesion to the lead frame at 25°C and can be peeled off from the lead frame and encapsulant after resin encapsulation, allowing semiconductor packages to be manufactured with high workability and productivity. In contrast, the adhesive films for semiconductors of the comparative examples, in which the surface roughness (Ra) of the back surface is less than 0.1 μm under condition 1 and less than 0.4 μm under condition 2, exhibit poor sliding on the stage during the semiconductor assembly process, causing transport problems and resulting in workability and productivity inferior to the temporary protective films of the examples.

[0115] Comparative Example 2 A 25 μm-thick polyimide film (Ube Industries, Ltd., Upilex SPA) was used as the support film. Varnish A-1 was cast to a thickness of 40 μm on one side of this polyimide film. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to obtain a temporary protective film with a 6 μm-thick adhesive layer on one side of the support film. The adhesive layer had a glass transition temperature of 230°C, a 5% weight loss temperature of 451°C, and an elastic modulus at 230°C of 150 MPa. Furthermore, varnish B-1 was cast to a thickness of 35 μm on the side of the polyimide film opposite the adhesive layer. The coating was dried at 100°C for 10 minutes and then at 300°C for 10 minutes to form a 5 μm-thick non-adhesive layer. This non-adhesive layer had a glass transition temperature of 260°C, a 5% weight loss temperature of 421°C, and an elastic modulus of 1700 MPa at 230°C. As a result, a temporary protective film of Comparative Example 2 was obtained, in which an adhesive layer was provided on one side of the support film and a non-adhesive layer was provided on the other side, as shown in Figure 1. The ratio of the thickness (A) of the adhesive layer to the thickness (C) of the support film was 0.24. In the temporary protective film of Comparative Example 2, the surface roughness (Ra) of the surface of the non-adhesive layer opposite to the surface in contact with the support film (the back surface of the temporary protective film) was 0.06 μm under condition 1 and 0.3 μm under condition 2.

[0116] (Evaluation of slipperiness of the backside of temporary protective film) The slipperiness of the surface (back surface) opposite to the surface in contact with the lead frame of the temporary protective films of Examples 1, 2, and 3, and Comparative Examples 1 and 2, was evaluated by the following friction test. The temporary protective film was fixed to a flat table with the surface not in contact with the lead frame (back surface) facing up. A standard flat attachment for force gauges, type A-2 (manufactured by Imada Co., Ltd., made of aluminum, weighing 2.5 g, diameter 13 mm) was placed on the temporary protective film with its flat surface facing down and slid, and the maximum stress at that time was measured using a force gauge (DPS-0.5, manufactured by Imada Co., Ltd.). The measurement results are shown in Table 1.

[0117] [Table 1]

[0118] The temporary protective films of the Examples had a lower maximum stress value in the friction test than the temporary protective films of the Comparative Examples. When the temporary protective film of Example 1 was used, it was confirmed that there were no transport problems. In contrast, when the temporary protective film of Comparative Example 1 was used, transport problems occurred. It can be said that transport problems are sufficiently suppressed even in the case of the temporary protective films of Examples 1 and 2, which showed maximum stress values ​​equal to or lower than the maximum stress value of the temporary protective film of Example 1 in the friction test. [Explanation of symbols]

[0119] 1...support film, 2...adhesive layer, 3...non-adhesive layer, 10...temporary protective film, 11...lead frame, 11a...die pad, 11b...inner lead, 12...wire, 13...sealing layer, 14...semiconductor element, 20...sealed molded body, 30...reel body, 31...winding core, 32...side plate, 40...packaging bag, 50...packaging body, 60...packaging box, 70...packaged item, 100...semiconductor device.

Claims

1. A temporary protective film for semiconductor encapsulation molding for temporarily protecting a lead frame during encapsulation molding to form an encapsulation layer that encapsulates a semiconductor element mounted on the lead frame, The present invention comprises a support film, an adhesive layer provided on one surface of the support film, and a non-adhesive layer provided on a surface of the support film opposite to the surface on which the adhesive layer is provided, the non-adhesive layer comprises an aromatic polyetheramideimide, The thickness of the non-adhesive layer is 10 μm or less, A temporary protective film for semiconductor encapsulation molding, wherein the surface roughness Ra of the surface of the non-adhesive layer opposite to the surface in contact with the support film is 0.1 μm or more, and the surface roughness Ra is a value measured using a laser microscope with an objective lens magnification of 50 times.

2. 2. The temporary protective film for semiconductor encapsulation molding according to claim 1, wherein the 90-degree peel strength between the adhesive layer and the lead frame when the temporary protective film is attached to a lead frame having a die pad and an inner lead so that the adhesive layer is in contact with the lead frame is 5 N / m or more at 25°C.

3. The temporary protective film is attached to a lead frame having a die pad and an inner lead so that the adhesive layer is in contact with the lead frame, a semiconductor element is mounted on the surface of the die pad opposite the temporary protective film, and an encapsulating layer is formed that encapsulates the semiconductor element while in contact with the adhesive layer. The 90-degree peel strength between the adhesive layer and the lead frame and the encapsulating layer is 1000 N / m or less in at least a part of the temperature range of 0 to 250 ° C. The temporary protective film for semiconductor encapsulation molding according to claim 1 or 2.

4. The 90 degree peel strength between the adhesive layer and the lead frame and the encapsulating layer is 1000 N / m or less in at least a part of a temperature range of 80 to 250 ° C. Temporary protective film for semiconductor encapsulation molding according to claim 3.

5. The 90-degree peel strength between the adhesive layer and the lead frame and the sealing layer is 1000 N / m or less at the temperature when the temporary protective film is peeled off from the lead frame and the sealing layer. Temporary protective film for semiconductor encapsulation molding according to claim 3 or 4.

6. The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 5, wherein the adhesive layer has a glass transition temperature of 100 to 300 ° C.

7. The temporary protective film for semiconductor encapsulation according to any one of claims 1 to 6, wherein the adhesive layer has an elastic modulus of 1 MPa or more at 230 ° C.

8. The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 7, wherein the adhesive layer has a 5% weight loss temperature of 300°C or higher.

9. The adhesive layer contains a thermoplastic resin having at least one functional group selected from the group consisting of an amide group, an ester group, an imide group, an ether group, and a sulfone group. The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 8.

10. The adhesive layer contains a thermoplastic resin having at least one functional group selected from the group consisting of an amide group, an ester group, an imide group, and an ether group. Temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 8.

11. The support film is a film containing a polymer selected from the group consisting of aromatic polyimide, aromatic polyamide, aromatic polyamideimide, aromatic polysulfone, aromatic polyethersulfone, polyphenylene sulfide, aromatic polyether ketone, polyarylate, aromatic polyether ether ketone and polyethylene naphthalate. The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 8.

12. The temporary protective film for semiconductor encapsulation according to any one of claims 1 to 11, wherein the ratio of the thickness of the adhesive layer to the thickness of the support film is 0.5 or less.

13. The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 12, wherein the non-adhesive layer has an elastic modulus of 10 MPa or more at 230 ° C.

14. A reel body comprising a winding core and the temporary protective film for semiconductor encapsulation according to any one of claims 1 to 13 wound around the winding core.

15. a lead frame having a die pad and inner leads; The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 13, Equipped with The lead frame with a temporary protective film, wherein the temporary protective film is attached to the lead frame so that the adhesive layer of the temporary protective film contacts one surface of the lead frame.

16. a lead frame having a die pad and inner leads; a semiconductor element mounted on the die pad; a wire connecting the semiconductor element and the inner lead; an encapsulation layer encapsulating the semiconductor element and the wire; The temporary protective film for semiconductor encapsulation molding according to any one of claims 1 to 13, Equipped with The temporary protective film has an adhesive layer attached to the surface of the lead frame opposite to the surface on which the semiconductor element is mounted.

17. A step of attaching the temporary protective film for semiconductor encapsulation according to any one of claims 1 to 13 to one side of a lead frame having a die pad and an inner lead, with the adhesive layer in a direction in which it contacts the lead frame; a step of mounting a semiconductor element on a surface of the die pad opposite to the temporary protective film; providing a wire connecting the semiconductor element and the inner lead; forming an encapsulating layer that encapsulates the semiconductor element and the wires to obtain an encapsulated molded body having the lead frame, the semiconductor element, and the encapsulating layer; peeling the temporary protective film from the encapsulated molded body; A method for manufacturing a semiconductor device, comprising the steps of:

18. 18. The method for manufacturing a semiconductor device according to claim 17, further comprising the step of connecting the semiconductor element mounted on the die pad and the inner leads with a conductive material by reflow.

Images