TWI770112B - Adhesive sheet for manufacturing semiconductor device and method for manufacturing semiconductor device using the same - Google Patents

Abstract

The present invention relates to an adhesive sheet for manufacturing a semiconductor device. In the adhesive sheet for manufacturing a semiconductor device which includes a substrate, and a thermo-setting type adhesive layer provided on one surface of the substrate mentioned above, and which is to be releasably adhered to a wiring board or a lead frame of the semiconductor device, the adhesive layer mentioned above contains (a) a carboxyl group-containing acrylonitrile – butadiene copolymer, (b) an epoxy resin having the following structural formula (1), (c) a compound having two or more maleimide groups, and (d) a reactive siloxane compound. In addition, the present invention provides a method for manufacturing a semiconductor device using the adhesive sheet mentioned above.

Description

Bonding sheet for semiconductor device manufacturing and method for manufacturing semiconductor device using the same

The present invention relates to an adhesive sheet suitable for use as a mask tape when assembling a semiconductor device using a QFN (Quad Flat Non-lead) method, and a manufacturing method of a semiconductor device using the adhesive sheet . In this case, priority is claimed based on Japanese Patent Application No. 2017-017490 filed in Japan on February 2, 2017, and its content is incorporated herein.

In recent years, in response to the requirements for miniaturization, thinning, and multi-functionalization of IT equipment including mobile phones, the need for higher-density mounting technology for semiconductor devices (semiconductor packages) has been increasing. In response to this demand, the CSP (Chip Size Package) technology has attracted much attention (see Patent Document 1 and Patent Document 2), and is especially widely used in low-pin-count types with less than 100 pins.

Here, an assembly method of a general QFN package based on the QFN method is generally known as the following method. First, in the attaching step, the adhesive sheet is attached to one surface of the lead frame, and then in the die bonding step, IC chips and the like are respectively mounted on a plurality of semiconductor element mounting portions (die seat portions) formed on the lead frame. semiconductor components. Then, in the wire bonding step, a plurality of leads arranged along the outer periphery of each semiconductor element mounting portion of the lead frame are electrically connected to the semiconductor elements by using bonding wires. Subsequently, in the sealing step, the semiconductor element mounted on the lead frame is sealed with a sealing resin. Then in the peeling step, by peeling off the adhesive sheet from the lead frame, a QFN cell in which a plurality of QFN packages are arranged can be formed. Finally, in the dicing step, a plurality of QFN packages can be fabricated by dicing the QFN along the periphery of each QFN package.

Adhesive sheets used for this purpose must be stably attached until the peeling step without peeling off from the inner surface of the lead frame and the inner surface of the sealing resin, and can be easily peeled off during the peeling step without adhesion. Residual adhesive residue on the inner surface of the lead frame or the inner surface of the sealing resin, or the adhesive chip is broken. In particular, in recent years, in order to reduce the cost of semiconductor devices, lead frames made of copper alloys have been used. This lead frame made of copper alloy will have the catalytic effect of copper, which is a migration metal, to oxidize and degrade the polymer material. With the thermal history of the QFN package after the adhesive bonding step, the adhesive is easily oxidized and deteriorated, and it is easy to be peeled off. It is easy to become heavy peeling and glue residue when the sheet is used.

However, the conventional splices are not sufficiently practical for use in leadframes constructed of copper alloys. For example, there is a conventional adhesive sheet in which an adhesive layer containing an acrylonitrile-butadiene copolymer and a bismaleimide resin is laminated on a base material composed of a heat-resistant film (see Patent Document 3). When this form is used, the acrylonitrile-butadiene copolymer is easily deteriorated due to the heat applied in the die attach cure process, the wire bonding process, and the resin sealing process after the sticking process, and the acrylonitrile-butadiene copolymer is easily deteriorated in the peeling process. There are problems such as becoming difficult to peel off, cracking of adhesive sheets, or generation of adhesive residues.

Prior Art Documents Patent Documents Patent Document 1: Japanese Patent Application Laid-Open No. 2003-165961 Patent Document 2: Japanese Patent Application Laid-Open No. 2005-142401 Patent Document 3: Japanese Patent Application Laid-Open No. 2008-095014

PROBLEM TO BE SOLVED BY THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an adhesive sheet and a method for manufacturing a semiconductor device using the adhesive sheet, which are subjected to QFN assembly until the peeling step. the thermal history, it is fully and stably attached without peeling off from the inner surface of the lead frame and the inner surface of the sealing resin, and the sealing resin will not leak, and it can be easily peeled off in the peeling step, and there will be no problems such as adhesives. Residual glue residue, or cracks, etc.

MEANS TO SOLVE THE PROBLEM The adhesive sheet for semiconductor device manufacture of this invention is characterized by having a base material and a thermosetting adhesive layer provided on one surface of the base material, and being capable of being releasably attached to a lead wire of a semiconductor device. A frame or a wiring board; wherein the above-mentioned adhesive layer contains: a carboxyl-containing acrylonitrile-butadiene copolymer (a), an epoxy resin (b) having the following structural formula (1), containing 2 or more maleic amides Amine-based compound (c) and reactive siloxane compound (d).

[Chemical formula 1]

Furthermore, the component (a) is preferably a carboxyl group-containing acrylonitrile-butadiene copolymer having an acrylonitrile content of 5 to 50 mass % and a carboxyl group equivalent calculated from the number average molecular weight of 100 to 20,000.

It is preferable that the total of the said (b) component, the said (c) component, and the said (d) component is 30-300 mass parts with respect to 100 mass parts of said (a) components. Moreover, it is preferable that the mass ratio ((c)/(b)) of (c) component with respect to the said (b) component is in the range of 0.1-10. Moreover, the ratio of the number of reactive groups of the component (d) to the sum of the number of epoxy groups of the component (b) and the number of maleimide groups of the component (c) is preferably 0.05 to 1.2. Further, the method of manufacturing a semiconductor device of the present invention is a method of manufacturing a semiconductor device using the adhesive sheet for manufacturing a semiconductor device described above, characterized by having the following steps: an attaching step of attaching a semiconductor to a lead frame or a wiring board A bonding sheet for device manufacturing; a die bonding step of mounting a semiconductor element on the lead frame or a wiring board; a wire bonding step of making the semiconductor element and external connection terminals conductive; a sealing step of sealing the semiconductor element with a sealing resin; and a peeling step , after the aforementioned sealing step, the adhesive sheet for manufacturing a semiconductor device is peeled off from the lead frame or the wiring board.

Advantageous Effects of Invention According to the present invention, it is possible to provide an adhesive sheet and a method for manufacturing a semiconductor device using the adhesive sheet, which are sufficiently and stably attached even if the adhesive sheet undergoes the thermal history accompanying the QFN assembly until the peeling step It does not peel off from the inner surface of the lead frame and the inner surface of the sealing resin, and the sealing resin does not leak, and can be easily peeled off in the peeling step, and there is no adhesive residue such as adhesive residue or cracking.

The present invention will be described in detail below. [Adhesive Sheet for Manufacturing a Semiconductor Device] The adhesive sheet for manufacturing a semiconductor device (hereinafter referred to as an adhesive sheet) of the present invention has a base material and a thermosetting adhesive layer provided on one surface of the base material, and can be releasably attached A lead frame or a wiring board attached to a semiconductor device, wherein the adhesive layer contains a carboxyl group-containing acrylonitrile-butadiene copolymer (a), an epoxy resin (b) having the following structural formula (1), containing two The maleimide-based compound (c) and the reactive siloxane compound (d) above are used as a mask tape when assembling a semiconductor device by a QFN method.

[Chemical formula 2]

The carboxyl group-containing acrylonitrile-butadiene copolymer (a) plays an effect of maintaining the melt viscosity of the adhesive layer moderately at the initial stage of heating, and at the same time imparts good flexibility and adhesiveness to the hardened adhesive layer, By containing this component, it is possible to have good adhesion to a base material made of a heat-resistant film or the like, and to form an adhesive layer that does not break. As the carboxyl group-containing acrylonitrile-butadiene copolymer (a), known ones can be used without limitation, but the content of acrylonitrile is preferably 5 to 50 mass %, preferably 10 to 40 mass %. When the content of acrylonitrile is less than the above range, the solubility to the solvent and the compatibility with other components will decrease, so that the obtained adhesive layer tends to decrease in uniformity. On the other hand, if the content of acrylonitrile exceeds the above-mentioned range, the adhesiveness of the obtained adhesive layer to the lead frame or the sealing resin becomes excessive, and when the adhesive sheet is used, it becomes difficult to peel off in the peeling step, and the adhesive sheet is broken. etc. possibility.

The carboxyl group equivalent calculated from the number average molecular weight of the carboxyl group-containing acrylonitrile-butadiene copolymer is preferably in the range of 100 to 20,000, and more preferably 200 to 10,000. When the carboxyl group equivalent is less than the above-mentioned range, the reactivity with other components becomes too high, and the storage stability of the obtained adhesive layer tends to decrease. On the other hand, if the carboxyl group equivalent exceeds the above-mentioned range, the reactivity with other components will be insufficient, so that the obtained adhesive layer tends to become a low B-stage (B-stage, pre-hardening stage). As a result, when it is used for adhesive sheets, at the initial stage of heating (ie, the attaching step of the adhesive sheet or the die-bonding curing process, etc.), when the adhesive sheet has been heated, the adhesive layer will become low in viscosity, and the adhesive layer will be easily formed. Foaming or overflow, etc., the thermal stability tends to decrease. In addition, the carboxyl group equivalent calculated from the number average molecular weight is obtained by dividing the number average molecular weight (Mn) by the number of carboxyl groups (functional group number) per molecule, and is represented by the following formula. Carboxyl equivalent = Mn/number of functional groups

The epoxy resin (b) and the compound (c) containing two or more maleimide groups are responsible for the thermosetting properties of the adhesive layer, and by using them together, it is possible to form an excellent thermal stability and an easy peeling step. Adhesive layer that peels without residue or cracking. In particular, the epoxy resin (b) imparts toughness to the adhesive layer, and by containing this component, it is possible to suppress adhesive residue due to cracking of the adhesive layer in the peeling step.

The compound (c) containing two or more maleimide groups plays the role of imparting thermal stability to the adhesive layer and adjusting the adhesiveness of the adhesive layer at the same time. Adhesive layer that can be easily peeled off in the peeling step. As a specific example of the compound (c) containing two or more maleimide groups, a compound constituting a bismaleimide resin is preferably used, and examples thereof include compounds of the following formulae (2-1) to (2-3), etc. , but the compound represented by the following formula (2-1) or (2-3) is particularly beneficial in terms of solubility in a solvent.

[Chemical formula 3]

The reactive siloxane compound (d) is used to improve the compatibility of the components constituting the adhesive layer and at the same time improve the releasability to the sealing resin of the adhesive layer. By containing this compound, the components can be formed into good compatibility. And a uniform adhesive layer without problems such as component separation and precipitation. As a result, the adhesive layer becomes uniform in adhesive strength, and defects such as a drop in peelability and adhesive residue due to localized high adhesive strength can be suppressed. As the reactive siloxane compound (d), a siloxane compound to which reactivity is imparted by reactive groups, such as amino group modification, epoxy modification, carboxyl modification, and mercapto modification, can be used without limitation. Among them, 1,3-bis(3-aminopropyl)tetramethyldisiloxane, aminopropyl-terminated dimethylsiloxane 4-mer or 8-mer, bis(3- Aminophenoxymethyl)tetramethyldisiloxane is suitable because the reaction with (b) component and (c) component proceeds rapidly. The use of such a compound having reactive groups bonded to both ends of the siloxane structure as the reactive siloxane compound (d) is suitable from the viewpoint of reactivity, but a single-ended compound or a single-ended compound may also be used. One is a reactive and the other is a non-reactive silane coupling agent.

In addition, any one of the above-mentioned components (a) to (d) may be composed of one kind of compound, or a mixture of two or more kinds of compounds may be used.

In terms of the ratio of each component, with respect to 100 parts by mass of component (a), the total of component (b), (c) and (d) is preferably 30 to 300 parts by mass, and preferably 30 to 200 parts by mass . If the total of the components (b), (c), and (d) is less than the above-mentioned range, the reactivity of the adhesive layer will be low, the insoluble and infusible (becoming insoluble and infusible) will be difficult to proceed even if heated, and the adhesive layer will be difficult to perform due to heat. The stability decreases and the bonding force tends to become stronger. On the other hand, if the above range is exceeded, the melt viscosity of the adhesive layer may be insufficient at the initial stage of heating, or the adhesive layer using the adhesive layer may have an adhesive layer after the die bonding and curing process after the bonding step. flow or foaming.

In addition, the mass ratio ((c)/(b)) of the (c) component with respect to the (b) component is preferably in the range of 0.1 to 10, and more preferably in the range of 1 to 7. If it is less than the above range, the obtained adhesive layer may become easy to undergo a hardening reaction at room temperature and the storage stability may be deteriorated, or the adhesive force may become too strong, and the adhesive sheet using the adhesive layer may be peeled off. It may become impossible to peel or even crack. On the other hand, when the above-mentioned range is exceeded, the adhesiveness with the base material composed of the adhesive layer and the heat-resistant film may be deteriorated when the adhesive sheet is produced, or the adhesive layer may be foamed, and the resulting adhesive sheet may be deteriorated. Tendency to become easy to glue residue.

Furthermore, the ratio of the number of reactive groups of the component (d) to the sum of the number of epoxy groups of the component (b) and the number of maleimide groups of the component (c) is preferably 0.05 to 1.2, more preferably 0.1 to 0.8. If it is less than the said range, the reactivity of the whole adhesive bond layer may fall, and it may become difficult to progress the hardening reaction at the time of die-bonding curing treatment or the like, and as a result, the adhesive force may become too strong. On the other hand, when it exceeds the said range, it becomes easy to have a problem, such as a reaction progresses excessively and gelatinization occurs at the time of preparation of an adhesive agent layer, and an adhesive force becomes weak easily.

In the adhesive layer, reaction accelerators such as organic peroxides, imidazoles, and triphenylphosphine may be added in addition to the respective essential components (a) to (d). By adding these or the like, the state of the adhesive layer at normal temperature can be controlled to a favorable B-stage. Furthermore, a filler having an average particle diameter of 1 μm or less may be added for the purpose of controlling melt viscosity, improving thermal conductivity, imparting flame retardancy, and the like. Examples of fillers include inorganic fillers such as silicon oxide, aluminum oxide, magnesium oxide, aluminum nitride, boron nitride, titanium oxide, calcium carbonate, and aluminum hydroxide, and organic fillers such as polysiloxane and fluororesin. When a filler is used, the content of the filler is preferably 1 to 40% by mass in the adhesive layer.

In the adhesive sheet of the present invention, the above-mentioned adhesive layer is formed on one side of a heat-resistant film serving as a base material. When manufacturing such an adhesive sheet, an adhesive coating must be prepared first, which is composed of at least the carboxyl-containing acrylonitrile-butadiene copolymer (a), the epoxy resin (b) having the structural formula (1), and the The compound (c) having two or more maleimide groups, the reactive siloxane compound (d), and a solvent are formed. Next, the coating material is applied to one side of the heat-resistant film so that the thickness of the adhesive layer after drying is preferably 1 to 50 μm, preferably 3 to 20 μm, and dried. In addition, in order to protect the adhesive layer, it is appropriate to further dispose a peelable protective film on the formed adhesive layer. In this case, an adhesive sheet can also be produced by the following method: coating the protective film and drying it to form The adhesive layer is then adhered, and a heat-resistant film is provided thereon. In addition, the protective film is peeled off when the adhesive sheet is used.

The heat-resistant film includes, for example, heat-resistant films composed of polyimide, polyphenylene sulfide, polyether sulfide, polyether ether ketone, liquid crystal polymer, polyethylene terephthalate, polyethylene naphthalate, and the like. Plastic film, epoxy resin-glass fiber cloth and other composite heat-resistant films, etc., especially polyimide film is suitable. The thickness of the polyimide film is preferably 12.5-125 μm, preferably 25-50 μm. If it falls below the above-mentioned range, the toughness of the adhesive sheet tends to be insufficient and handling becomes difficult; if it exceeds the above-mentioned range, the operation of the adhesive bonding step or the peeling step during QFN assembly tends to become difficult.

The solvent used in the adhesive coating can preferably use one or more organic solvents such as hydrocarbons, alcohols, ketones, ethers (tetrahydrofuran, etc.), water, etc., and the amount used should be appropriately adjusted so that the coating has an appropriate viscosity. That's it. In addition, the form of the coating material may be any of a solution, an emulsion, and a suspension, and can be appropriately selected according to the coating apparatus used and the environmental conditions.

The peelable protective film includes plastic films such as polyethylene, polypropylene, vinyl chloride, fluorine-based resin, polysiloxane, etc., polyethylene terephthalate, polyethylene naphthalate, paper, etc. Silica coating or the like imparts peelability.

[Manufacturing Method of Semiconductor Device] The manufacturing method of a semiconductor device using the adhesive sheet of the present invention includes the following steps: an attaching step of attaching the adhesive sheet to a lead frame or a wiring board; a die bonding step of attaching the adhesive sheet to the lead frame or wiring substrate Mounting a semiconductor element; a wire bonding step for conducting the semiconductor element with an external connection terminal; a sealing step for sealing the semiconductor element with a sealing resin; and a peeling step for peeling off the adhesive sheet from the lead frame or the wiring board after the sealing step.

Hereinafter, with reference to FIGS. 1-2, an example of the manufacturing method of the semiconductor device using the adhesive sheet of this invention is demonstrated. 1 is a top view of the lead frame seen from the side where the semiconductor element is mounted; FIGS. 2(a) to (f) are step diagrams showing a method of manufacturing a QFN package using the lead frame shown in FIG. A-A' section view.

First, the lead frame 20 of the schematic structure shown in FIG. 1 is prepared. In the lead frame 20, a plurality of semiconductor element mounting portions (die seat portions) 21 on which semiconductor elements such as IC chips are mounted are formed in an array, and a plurality of leads 22 (external connection) are formed along the outer periphery of each semiconductor element mounting portion 21. terminal). The material of the lead frame 20 can be anything known in the art, such as copper plate and copper alloy plate, or those with primer plating layer on them, or the surface of copper alloy plate is sequentially provided with nickel plating layer, Palladium-coated and gold-coated.

As shown in FIG. 2( a ), the adhesive sheet 10 is attached to one side (lower surface) of the lead frame 20 so that an adhesive layer (not shown) is in contact with the lead frame 20 (attachment step). The method of attaching the adhesive sheet 10 to the lead frame 20 includes a lamination method, a lamination method, and the like, but from the viewpoint of productivity, a lamination method capable of continuously performing an adhesive bonding process is preferable. In this step, the temperature of the adhesive sheet 10 is set, for example, from normal temperature (5-35°C) to 150°C, and preferably 60-120°C. If it is attached at a temperature higher than 150° C., warpage of the lead frame is likely to occur. Once the lead frame 20 is warped in this step, there is a possibility that the positioning of the die bonding step or the wire bonding step will become difficult, or the transportation to the heating furnace will become difficult, which may reduce the productivity of the QFN package.

As shown in FIG. 2( b ), on the side of the semiconductor element mounting portion 21 of the lead frame 20 to which the adhesive sheet 10 is attached, a semiconductor element 30 such as an IC chip is mounted via a die bonder (not shown). At this time, the lead frame 20 is easily positioned because warpage is suppressed. Accordingly, the semiconductor element 30 is correctly placed in a predetermined position. Then, it heats to about 100-200 degreeC, the die-bonding agent is hardened, and the semiconductor element 30 is fixed and mounted on the semiconductor element mounting part 21. (The die-bonding agent curing process. The above is the die-bonding step.) At this time, the adhesive layer of the adhesive sheet 10 is cured and attached to the lead frame.

Once the outgassing components generated from the adhesive sheet 10 or the die bonder adhere to the lead frame 20 or the semiconductor element 30 , a decrease in yield due to poor wire bonding is likely to occur in the wire bonding step. Therefore, after the die bonding step and before the wire bonding step, a plasma treatment (plasma cleaning step) is applied to the lead frame 20 or the semiconductor element 30 . Plasma treatment includes, for example, a method of irradiating a lead frame 20 (hereinafter also referred to as a semi-finished product) on which the semiconductor element 30 is mounted with the adhesive sheet 10 under an ambient gas such as argon gas or a mixed gas of argon gas and hydrogen gas. The plasma irradiation output power at the time of plasma treatment is, for example, 150 to 600 W. In addition, the time of the plasma treatment is, for example, 0.1 to 15 minutes.

As shown in FIG. 2( c ), the leads 22 (external connection terminals) of the semiconductor element 30 and the lead frame 20 are electrically connected to bonding wires 31 such as gold wires, copper wires, and palladium-clad copper wires (wire bonding step). This step is performed while heating the semi-finished product to about 150-250° C. on a heating block. The heating time in this step is set to, for example, 5 to 60 minutes. Once the semi-finished product is heated in the wire bonding step, when the adhesive layer contains a fluorine additive, the fluorine additive will move to the surface of the adhesive layer. Therefore, in the peeling step described later, the adhesive sheet 10 can be easily peeled off from the lead frame 20 and the sealing resin 40 .

As shown in FIG. 2( d ), the semi-finished product shown in FIG. 2( c ) is placed in a mold, and is injected and molded in the mold using a sealing resin (mold). After filling an arbitrary amount in the mold, the semiconductor element 30 is sealed with the sealing resin 40 by keeping the inside of the mold under an arbitrary pressure (sealing step). As a sealing resin, a conventional thing can be used, for example, the mixture of an epoxy resin, an inorganic filler, etc. is mentioned. As shown in FIG. 2( e ), by peeling off the adhesive sheet 10 from the sealing resin 40 and the lead frame 20 , a QFN unit 60 in which a plurality of QFN packages 50 are arranged is obtained (peeling step).

As shown in FIG. 2( f ), a plurality of QFN packages 50 are obtained by cutting the QFN cells 60 along the outer periphery of each QFN package 50 (cutting step).

In addition, in the above-mentioned embodiments, the method of manufacturing a QFN package using a lead frame is described as an example, but the present invention is not limited to this, and can also be applied to a method of manufacturing semiconductor devices other than the QFN package using a lead frame, A method of manufacturing a semiconductor device using a wiring board.

The adhesive layer in the adhesive sheet of the present invention can be B-staged by crosslinking the carboxyl group of the carboxyl group-containing acrylonitrile-butadiene copolymer (a) with the glycidyl group of the epoxy resin (b). state (semi-hardened state), and made into a low glass transition temperature (10 ℃ ~ 50 ℃). The adhesive sheet with an adhesive layer with a low glass transition temperature can be continuously applied with a roller press under a relatively low temperature heating condition (specifically, 60~150°C), and has excellent productivity.

In addition, in the adhesive sheet of the present invention, the adhesive layer with a low glass transition temperature (10° C. to 50° C.) can obtain the property of high elastic modulus during heating. In recent years, for the purpose of reducing the cost of the wire bonding step, products using low-cost copper wires or palladium-clad copper wires to replace traditional gold wires for bonding have become popular. Since copper wire or palladium-clad copper wire is a metal with higher elasticity than gold, in order to make it into a stable shape, it must be processed with a higher load than traditional gold wire. If such a large load is applied to the lead frame, once the adhesive layer in the adhesive sheet attached to the lower part of the lead frame has a low elastic modulus, the adhesive layer is deformed and the adhesive layer of the deformed adhesive layer is deformed. The state is sealed with resin. As a result, the sealing resin leaks from the deformed adhesive layer portion. In addition, when the adhesive sheet is peeled off from the lead frame, there is also a problem that the adhesive layer is partially broken from the deformed adhesive layer and the adhesive remains on the surface of the lead frame. In addition, once the adhesive agent has a low elastic modulus during wire bonding, the wire load is difficult to transmit due to the deformation of the adhesive agent, and the wire bonding failure is likely to occur. Since the adhesive layer in the adhesive sheet of the present invention has the characteristics of high elastic modulus as mentioned above, even if copper wire or palladium-clad copper wire is used for wire bonding, poor wire bonding, leakage of sealing resin or leakage of sealing resin is difficult to occur. The problem of remaining agent layer.

In addition, since the adhesive layer of the adhesive sheet of the present invention contains the compound (c) containing two or more maleimide groups, the hardening of the adhesive layer during the drying process can be appropriately controlled when the adhesive sheet is produced, and the adhesive The adhesive layer is in a high B-stage state, so that the increase in the bonding strength to the lead frame is suppressed. As a result, leakage of the sealing resin, residue of the adhesive on the lead frame, and cracking of the adhesive layer during peeling can be suppressed.

EXAMPLES The present invention is specifically described by showing examples below. [Examples 1 to 6 and Comparative Examples 1 to 4] (Composition of Adhesive Paint) Components (a) to (d) and other components were mixed with tetrahydrofuran (THF) as a solvent at the mass ratio shown in Table 1 to prepare adhesive agent paint. Then, the adhesive coating was applied on one side of a polyimide film with a thickness of 25 μm (manufactured by Toray-DuPont, trade name KAPTON 100EN) so that the adhesive layer thickness after drying was 5 μm. The adhesive sheet was obtained by drying in a hot air circulation type oven at 180°C. In addition, each component used is as follows in detail.

・Carboxyl group-containing acrylonitrile-butadiene copolymer: carboxyl group equivalent calculated by number average molecular weight 1500, acrylonitrile content 27% by mass ・Acrylonitrile-butadiene copolymer: acrylonitrile content 27% by mass ・It has the structural formula ( 1) Epoxy resin: molecular weight 630, functional group equivalent 210g/eq ・Bisphenol A diphenyl ether bismaleimide: molecular weight 570, functional group equivalent 285g/eq ・1,3-bis(3-amine propyl) tetramethyldisiloxane: molecular weight 248, functional group equivalent 62g/eq

[Table 1]

With respect to the adhesive sheets of the respective examples obtained in the above-described manner, the following were measured or confirmed: (1) peel strength to the lead frame material, (2) thermal properties after the die bonding step, (3) peel strength to the sealing resin material And whether there is adhesive residue after the sheet is peeled off, and (4) whether the sealing resin of the test body leaks after the resin sealing step.

(1) Peel strength to lead frame material (i) Preparation of test body The adhesive sheet obtained in each example was cut into a width of 50 mm × length 60 mm, and was attached to a copper alloy with an outer dimension of 57.5 mm × 53.5 mm using a rolling machine The prepared test lead frame (surface coating, 8 × 8 array configuration, package size 5mm × 5mm, 32 pins), and the attached object is used as the test body. The lamination conditions at this time were a temperature of 80° C., a pressure of 4 N/cm, and a pressing speed of 1 m/min. (ii) Measurement of peel strength The 90° peel strength of the above-mentioned test body was measured using a universal tensile tester. Then, the lead frame was fixed, and the adhesive sheet was stretched in the vertical direction for measurement. The stretching speed was set to 50 mm/min. The results are shown in Table 2.

(2) Thermal properties after the bonding step For the adhesive sheets obtained in each example, a polyimide film with a thickness of 25 μm and a release-treated polyethylene terephthalate film with a thickness of 38 μm ( PET film), and simulating the die-bonding curing treatment and heating at 175° C. for 1 hour using a ventilated oven. After heating, the adhesive layer of the adhesive sheet was taken out from the PET film, and the tensile storage elastic modulus was measured using DMA (Dynamic Mechanical Analyzer, Dynamic Mechanical Analyzer). The DMA system was measured using a viscoelasticity measuring device (manufactured by Orientec, RHEOVIBRON DDV-II-EP) at a frequency of 11 Hz, a temperature increase rate of 10°C/min, and a load of 1.0 gf. Table 2 shows the results of the tensile storage elastic modulus at 180°C at the temperature used to simulate the wire bonding step.

(3) Peel strength of sealing resin material and presence or absence of adhesive residue after sheet peeling (i) Preparation of test body and heat treatment The following (a) to (d) are implemented. (a) The adhesive sheet obtained in each example was cut into a width of 50 mm × length of 60 mm, and was attached to a test lead frame made of a copper alloy with an outer dimension of 57.5 mm × 53.5 mm using a rolling machine (surface undercoating, 8 × 8 array configuration, package size 5mm × 5mm, 32 pins). The lamination conditions at this time were a temperature of 80° C., a pressure of 4 N/cm, and a pressing speed of 1 m/min. (b) The lead frame for testing made of copper alloy to which the adhesive sheet was attached was heated at 175° C./1 hour in a ventilation oven. This is a process that simulates a sticky die curing process. (c) Plasma irradiation treatment: 1000P manufactured by Yield Engineering Co., Ltd. was used, and Ar was used as the gas type, and 450W/60 second treatment was performed. (d) Heating at 200° C./30 minutes: To simulate the process of wire bonding, a heating plate was used for heating. Next, on the exposed surface of the copper material that has been heat-treated (a) to (d), the exposed surface of the copper material opposite to the surface to which the adhesive sheet has been attached is laminated with a sealing resin using a molding machine at 175°C/3/3. (resin sealing step). As the sealing resin, epoxy molding resin (EME-G631BQ) manufactured by Sumitomo Bakelite Co., Ltd. was used.

(ii) Peel strength and presence or absence of adhesive residue after sheet peeling The 90° peel strength was measured on the test body after the above-mentioned resin sealing step using a universal tensile tester. In addition, the test body was fixed, and the edge and corner portions of the adhesive sheet were stretched in the vertical direction for measurement. The stretching speed was set to 300 mm/min. Moreover, using an optical microscope (Digital Microscope VHX-500 manufactured by Keenes Corporation), the presence or absence of adhesive residue after peeling of the sheet was confirmed at a magnification of 100 times. The results are shown in Table 2. (4) Whether or not the sealing resin of the test body leaks after the resin sealing step Using an optical microscope (Digital Microscope VHX-500 manufactured by Keynes Corporation), the test body after the above resin sealing step is checked for leakage of the sealing resin at a magnification of 100 times. The results are shown in Table 2.

In addition, the symbols in the judgment column in Table 2 indicate the following. (1) Measurement of peel strength of lead frame material ○: The peel strength is 10 gf/50 mm or more. Δ: Peel strength is 5 gf/50 mm or more and less than 10 gf/50 mm. ×: The peel strength is less than 5 gf/50 mm.

(2) Thermal properties after the sticking step ○: Tensile storage elastic modulus at 180°C is more than 10 MPa Below 1MPa

(3) The peeling strength of the sealing resin material and whether there is any adhesive residue after peeling off the sheet ○: The peeling strength is lower than 1000gf/50mm, the peeled adhesive sheet is not broken, and there is no adhesive residue on the surface of the lead frame material and the sealing resin. . △: The peel strength is 1000 gf/50 mm or more, the adhesive sheet after peeling is not broken, and no adhesive remains on the surface of the lead frame material and the surface of the sealing resin. ×: Either of the following: the adhesive sheet was found to be broken, or the adhesive residue was found on the surface of the lead frame material and the surface of the sealing resin. (4) Is there any leakage of the sealing resin of the test body after the resin sealing step? ○: No sealing resin seeps out from the surface of the test lead frame material after the adhesive sheet is peeled off and the resin sealing is completed. ×: The sealing resin oozes out from the surface of the test lead frame material after the adhesive sheet is peeled off and the resin sealing is completed.

[Table 2]

As clearly shown in Table 2 above, the adhesive sheets of Examples 1 to 6 have a peel strength of 5 gf/50 mm or more to a copper alloy test lead frame, and have excellent adhesion to a lead frame material. It was also confirmed that the adhesive sheets of Examples 1 to 6 had a tensile storage modulus of elasticity at 180° C. of 10 MPa or more, and had the characteristic of being able to sufficiently withstand the deformation of the adhesive layer due to the load during the wire bonding step. In addition, the adhesive sheets of Examples 1 to 6 have excellent properties, the sealing resin does not leak, the substrate and the adhesive layer of the adhesive sheets are not broken, and there is no adhesive residue on the surface of the lead frame material and the surface of the sealing resin. On the other hand, it was confirmed that the adhesive sheets of Comparative Examples 1, 2 and 4 had a tensile storage elastic modulus of less than 10 MPa at 180° C., and it was difficult to withstand the adhesive layer caused by the load during the wire bonding step. deformed. Moreover, when the adhesive sheet of Comparative Examples 1-4 was peeled from the sealing resin material, the adhesive sheet was broken, and the adhesive agent remained on the surface of the lead frame material and the surface of the peeling sealing resin at the position where the sheet-like peeling was possible.

INDUSTRIAL APPLICABILITY The adhesive sheet of the present invention is suitable for use as a mask film when assembling a semiconductor device by a QFN (Quad Flat Non-lead) method. According to the adhesive sheet of the present invention, even if it undergoes the thermal history accompanying the QFN assembly, it is fully and stably attached without peeling off from the inner surface of the lead frame and the inner surface of the sealing resin until the peeling step, and the sealing resin will not be peeled off. There is no leakage, and it can be easily peeled off in the peeling step, and there will be no adhesive residues such as adhesive residues, or cracks. In addition, the adhesive sheet of the present invention is suitable for the manufacture of semiconductor devices.

10‧‧‧Adhesive Sheet for Semiconductor Device Manufacturing 20‧‧‧Lead Frame 21‧‧‧Semiconductor Element Mounting Part 22‧‧‧Lead 30‧‧‧Semiconductor Element 31‧‧‧Bonding Wire 40‧‧‧Sealing Resin 50‧‧ ‧QFN package A-A'‧‧‧Chat

FIG. 1 is a plan view showing an example of a lead frame used in a method of manufacturing a semiconductor device of the present invention. FIG. 2 is a step diagram illustrating a method of manufacturing the semiconductor device of the present invention.

Claims (6)

An adhesive sheet for manufacturing a semiconductor device, characterized by having a base material and a thermosetting adhesive layer provided on one surface of the base material, which can be releasably attached to a lead frame or a wiring board of a semiconductor device; wherein the aforementioned The adhesive layer contains: carboxyl-containing acrylonitrile-butadiene copolymer (a), epoxy resin (b) having the following structural formula (1), compound (c) containing two or more maleimide groups and reactive siloxane compound (d), [Chemical formula 1]

. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the component (a) is a carboxyl group-containing acrylonitrile-butyl having an acrylonitrile content of 5 to 50% by mass and a carboxyl group equivalent calculated from the number average molecular weight of 100 to 20,000 Diene copolymer. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the total of the component (b), the component (c), and the component (d) is 30 to 300 parts by mass relative to 100 parts by mass of the component (a). The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the mass ratio ((c)/(b)) of the component (c) to the component (b) is in the range of 0.1 to 10. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the ratio of the number of reactive groups of component (d) to the sum of the number of epoxy groups of component (b) and the number of maleimide groups of component (c) is 0.05~ 1.2. A method of manufacturing a semiconductor device, characterized by using the adhesive sheet for manufacturing a semiconductor device as claimed in claim 1, and having the following steps: an attaching step of attaching the adhesive sheet for manufacturing a semiconductor device to a lead frame or a wiring substrate; a die attaching step , mounting a semiconductor element on the lead frame or wiring substrate; a wire bonding step, making the semiconductor element and external connection terminals conduct; a sealing step, sealing the semiconductor element with a sealing resin; and a peeling step, after the sealing step, sealing the semiconductor element The adhesive sheet for device manufacturing is peeled off from the lead frame or the wiring board.

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