KR101485659B1 - Adhesive sheet for manufacturing semiconductor device and manufacturing method of semiconductor device - Google Patents

Abstract

The present invention provides an adhesive sheet for semiconductor device production with excellent peelability.
An adhesive sheet (10) for semiconductor device production, which comprises a substrate and an adhesive layer containing a fluorine-containing additive provided on one side of the substrate and is adhered to the lead frame (20) , Wherein the adhesive layer has a surface fluorine recovery of 70% or more as determined by the following formula (I).
Surface fluorine recovery (%) = Surface fluorine content after restoration α ÷ Initial surface fluorine content β × 100 ... (I)

Description

TECHNICAL FIELD [0001] The present invention relates to an adhesive sheet for semiconductor device manufacturing and a method of manufacturing the same. More particularly,

The present invention relates to an adhesive sheet for manufacturing a semiconductor device and a method of manufacturing the semiconductor device.

2. Description of the Related Art In recent years, with the miniaturization and multifunctionalization of electronic devices such as portable PCs and mobile phones, there has been a need for a high-density mounting technology for electronic components in addition to miniaturization and high integration of electronic components constituting electronic devices. Under such circumstances, a semiconductor device such as a CSP (Chip Scale Package) capable of high-density mounting has been attracting attention in place of peripheral mounting type semiconductor devices such as QFP (Quad Flat Package) and SOP (Small Outline Package). Among the CSPs, QFN (Quad Flat Non-leaded) packages are particularly suitable because they can be manufactured by applying conventional semiconductor device fabrication techniques, and they are mainly used as small-terminal type semiconductor devices of less than 100 pins .

As a method of manufacturing a QFN package, the following method is known roughly. First, an adhesive sheet is adhered to one surface of a lead frame in an adhering (sticking) step, and then a semiconductor element such as an IC chip is mounted on a semiconductor element mounting portion (die pad portion) do. Next, in the wire bonding step, a plurality of leads (arranged) along the periphery of each semiconductor element mounting portion of the lead frame and the semiconductor element are electrically connected by a bonding wire. Next, in the sealing step, the semiconductor element mounted on the lead frame is sealed with a sealing resin. Thereafter, in the peeling step, the adhesive sheet is peeled from the lead frame to form a QFN unit in which a plurality of QFN packages are arranged. Finally, in the dicing process, a plurality of QFN packages can be manufactured by dicing the QFN unit along the periphery of each QFN package.

Conventionally, an adhesive sheet for manufacturing a semiconductor device using a silicone adhesive or an acrylic adhesive has been used in a manufacturing method of a QFN package. However, when such an adhesive sheet for semiconductor device production is used, resin leakage (mold flash) may occur in the sealing process.

Furthermore, it has become common to provide a process (plasma cleaning process) for treating the plasma before the wire bonding process to further improve the wire bonding property by removing impurities attached to the surface of the semiconductor device and, for example, the lead frame . In the case of using the conventional adhesive sheet for semiconductor device fabrication, the surface of the adhesive-exposed surface of the adhesive sheet for semiconductor device fabrication becomes rough by plasma cleaning, so that when the adhesive sheet for semiconductor manufacturing is peeled off, ) (Hereinafter referred to as " residual adhesive ") may occur. As described above, in the case where the adhesive residue is generated, the adhesive is adhered to the portion sealed by the sealing resin or the external connection terminal portion of the lead in the vicinity thereof, so that when the manufactured semiconductor device is mounted on a wiring board or the like, .

To solve this problem, there has been proposed an adhesive sheet for manufacturing a semiconductor device having an adhesive layer containing a thermosetting resin component, a thermoplastic resin component and a fluorine-based additive (for example, Patent Document 1). According to the invention of Patent Document 1, since the wire bonding property is excellent even when the plasma is not treated, the residual adhesive by the plasma treatment can be reduced.

[Patent Document 1] JP-A-2007-123710

However, in the invention of Patent Document 1, there is a problem that although the adhesive residue can be reduced, the adhesive strength to the sealing resin is strong and it is difficult to peel off. Moreover, the adhesive sheet for manufacturing semiconductor devices is required to have a releasability such that it can be peeled off with a smaller peeling force in a manufacturing method provided with a plasma cleaning process.

Therefore, the object of the present invention is to provide an adhesive sheet for semiconductor device production which is excellent in peelability.

The adhesive sheet for manufacturing a semiconductor device of the present invention comprises a base material and an adhesive layer containing a fluorine-containing additive, provided on one side of the base material, for producing a semiconductor device which is adhered to a lead frame or a wiring substrate of the semiconductor device in a releasable manner. In the adhesive sheet, the adhesive layer has a surface fluorine recovery of 70% or more as determined by the following formula (I).

Surface fluorine recovery (%) = Surface fluorine content after restoration α ÷ Initial surface fluorine content β × 100 ... (I)

In the formula (I), the surface fluorine content after restoration? Is a value obtained by treating the adhesive layer with plasma at an output condition of 450 W for 1 minute under an argon gas atmosphere and then heating the adhesive layer at 220 占 폚 for 15 minutes Of fluorine (atom%). The initial surface fluorine content ratio? Is the fluorine content (atom%) of the surface of the adhesive layer before the plasma treatment.

The surface fluorine content after restoration? Is preferably 18 atomic% or more.

The method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device using the adhesive sheet for manufacturing a semiconductor device according to the present invention described above and is characterized by comprising an adhesion step of attaching the adhesive sheet for semiconductor device production to the lead frame or the wiring board, A step of heating the adhesive layer after the plasma cleaning step, and a step of heating the adhesive sheet for semiconductor device manufacturing from the lead frame or the wiring board after the plasma cleaning step, the heating step of heating the adhesive layer after the plasma cleaning step, And a peeling step of peeling off the substrate.

According to the adhesive sheet for manufacturing a semiconductor device of the present invention, the peelability is excellent.

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.
2 is a process diagram for explaining a manufacturing method of the semiconductor device of the present invention.

The adhesive sheet for manufacturing a semiconductor device of the present invention (hereinafter simply referred to as an adhesive sheet) is peelably adhered to a lead frame or a wiring board of a semiconductor device.

A lead frame is a metal plate formed by etching or pressing a conductor pattern. A wiring board is a conductor pattern formed on a surface (or an inner surface) of an electrically insulating substrate by a conductive material.

The adhesive sheet of the present invention comprises a substrate and an adhesive layer provided on one side of the substrate.

Examples of the base material include those having heat resistance, for example, heat-resistant resin films and metal foils.

When a semiconductor device such as a QFN package is manufactured using an adhesive sheet, the adhesive sheet is exposed to a high temperature of 150 to 250 DEG C in a diazep process, a wire bonding process, and a sealing process. When the heat-resistant resin film is used as a substrate, the thermal expansion coefficient of the heat-resistant film sharply increases when the glass transition temperature (Tg) is higher than the glass transition temperature (Tg). Therefore, when the temperature is returned to room temperature, the heat resistant film and the lead frame may be deformed. When the heat-resistant film and the lead frame are deformed, the lead frame can not be mounted on the positioning pin of the mold in the sealing process, and there is a fear that the position difference may be defective.

Therefore, when a heat resistant film is used as a substrate, it is preferably a heat resistant film having a glass transition temperature of 150 DEG C or higher, more preferably 180 DEG C or higher.

The coefficient of thermal expansion of the heat-resistant film at 150 to 250 ° C is preferably 5 to 50 ppm / ° C, more preferably 10 to 30 ppm / ° C. Examples of the heat resistant film having such characteristics include films made of polyimide, polyamide, polyethersulfone, polyphenylene sulfide, polyether ketone, polyether ether ketone, triacetyl cellulose, polyether imide and the like have.

Also, when the metal foil is used as the substrate, the coefficient of thermal expansion of the metal foil at 150 to 250 ° C is preferably 5 to 50 ppm / ° C, more preferably 10 to 30 ppm / ° C, for the same reason as the heat resistant film. As the metal, a foil made of gold, silver, copper, platinum, aluminum, magnesium, titanium, chromium, manganese, iron, cobalt, nickel, zinc, palladium, indium and tin, A foil or a plated foil.

In order to prevent the adhesive residue in the peeling step, which will be described later, when the semiconductor device is manufactured using the adhesive sheet of the present invention, the adhesive strength Sa between the substrate and the adhesive layer and the adhesive strength Sa between the sealing resin, The ratio (adhesion strength ratio) Sa / Sb of the adhesion strength Sb is preferably 1.5 or more. When Sa / Sb is less than 1.5, adhesive residue tends to occur in the adhesive sheet peeling step. Further, in order to make the adhesive strength ratio Sa / Sb to 1.5 or more, in the case of the heat-resistant film, the surface of the heat-resistant film on which the adhesive layer is formed is subjected to corona treatment, plasma treatment, primer treatment, It is preferable that the adhesive strength Sa between the heat-resistant film and the adhesive layer, such as an adhesive, is increased. In the case of a metal foil, the metal foil is classified into a rolled metal foil and an electrolytic metal foil according to the production method. However, in order to make the adhesive strength ratio Sa / Sb 1.5 or more, an adhesive layer is provided on the surface of the electrolytic metal foil, . Among electrolytic metal foils, electrolytic copper foil is preferably used.

The thickness of the base material is determined in consideration of the material and the like, and is, for example, 10 to 100 mu m.

The adhesive layer contains a fluorine-containing additive and has a surface fluorine recovery rate of 70% or more, which will be described later. When the surface fluorine recovery ratio is 70% or more, excellent peelability can be exhibited.

The adhesive layer may contain an additive containing fluorine, and may have any bonding strength to the lead frame or the wiring board, and may contain, for example, a fluorine-containing additive and a resin.

The fluorine-containing additives include, for example, sulfonate salts containing perfluoroalkyl groups, anionic surfactants such as carboxylates containing perfluoroalkyl groups, perfluoroalkyl alkylene oxide adducts, fluorine Fluorine-containing surfactants such as fluorine-containing hydrophilic group-containing oligomers, fluorine group-containing hydrophilic group-containing oligomers, fluorine group-containing hydrophilic group-lipophilic group-containing oligomer, and the like. Of these, nonionic surfactants And a fluorine group-lipophilic group-containing oligomer is more preferable. The anionic surfactant is a compound in which ionizing functional groups undergo electrostatic interaction in the resin, and the degree of freedom of the surfactant is low and the surface is not exposed. Examples of the lipophilic group include an alkyl group, an allyl group, a vinyl group, an alkyl ether group, an alkyl ester group, and an acrylate group. These fluorine-containing additives may be used alone or in combination of two or more.

The fluorine-containing additive to be incorporated may be a liquid or a solid, but it is preferably liquid at 25 占 폚 in view of increasing the surface fluorine recovery rate of the adhesive layer and further improving the peelability.

Examples of highly suitable fluorine-containing additives include MEGAFAC F-552, F-554 and F-558 (manufactured by DIC Co., Ltd.), which are oligomers containing a fluorine group and a lipophilic group which are liquid at 25 ° C have.

The content of the fluorine-containing additive in the adhesive layer is appropriately determined in consideration of the kind of the fluorine-containing additive, the kind and amount of the resin, and is, for example, preferably from 0.5 to 20 mass% By mass, more preferably 2.5% by mass to 5.0% by mass. If it is less than the above lower limit, there is a fear that the peelability is lowered. If it exceeds the upper limit value, the adhesive strength becomes insufficient and the mold flash property is lowered or there is a fear that the adhesive strength before curing described below becomes insufficient.

Examples of the resin in the adhesive layer include thermoplastic resins and thermosetting resins.

Examples of the thermoplastic resin include polybutadiene, polyacrylonitrile, polyvinyl butyral, polyamide, polyamideimide, polyimide, polyester, polyurethane, acrylic rubber and the like. Among them, reactive Elastomers are preferred.

The reactive elastomer has a functional group such as a carboxyl group, an amino group, a vinyl group and an epoxy group, or has an acid anhydride on its side chain, and thus has a reactivity. The reactive elastomer can be produced by copolymerizing a monomer having a functional group when the elastic resin is produced. Further, it can be produced by preparing an elastic resin having an unsaturated bond such as a vinyl bond and then introducing a functional group such as an epoxy group into an unsaturated bond such as a vinyl group. Examples of the monomer having a functional group include monomers having a vinyl bond and a functional group such as acrylic acid and methacrylic acid.

Examples of the reactive elastomer include styrene ethylene butylene styrene copolymer (SEBS) such as a carboxy group-containing styrene ethylene butylene styrene copolymer and a maleic anhydride-containing styrene ethylene butylene styrene copolymer, a carboxy group-containing styrene butadiene copolymer, Styrene-butadiene copolymers such as maleic anhydride-containing styrene butadiene copolymer and carboxy group-containing styrene butadiene saturated copolymer, styrene isoprene copolymers such as carboxy group-containing styrene isoprene copolymer and carboxy group-containing styrene isoprene copolymer, epoxy group- Styrene-based thermoplastic elastomers such as styrene-butadiene copolymer, styrene-butylene copolymer containing maleic anhydride; Acrylonitrile butadiene copolymer (NBR) such as acrylonitrile butadiene copolymer containing carboxyl group, acrylonitrile butadiene copolymer modified with amino group, and acrylonitrile butadiene copolymer containing hydrogenated carboxyl group; An amino group-modified polyol resin, an amino group-modified phenoxy resin, a polyvinyl butyral resin, a polyvinyl acetal resin, a carboxyl group-containing acrylic rubber, a hydroxy group terminal saturated copolymer resin polyester resin and a carboxyl group terminal saturated copolymer polyester resin. A styrene thermoplastic elastomer is preferable from the standpoint of heat resistance and the like, and SEBS is more preferable. Incidentally, "containing maleic anhydride" means having an acid anhydride in the side chain. These thermoplastic resins may be used alone or in combination of two or more.

Further, a thermoplastic resin containing fluorine (fluorine-containing thermoplastic resin) can be used as the thermoplastic resin.

Examples of the thermosetting resin include those used in conventional adhesive layers. Examples of the thermosetting resin include urea resin, melamine resin, benzoguanamine resin, acetoguanamine resin, phenol resin, resorcinol resin, xylene resin, furan resin, Unsaturated polyester resins, diallyl phthalate resins, isocyanate resins, epoxy resins, maleimide resins, and nadimide resins. These thermosetting resins may be used alone or in combination of two or more.

Further, a thermosetting resin containing fluorine (a fluorine-containing thermosetting resin) may be used as the thermosetting resin.

As the resin in the adhesive layer, a reactive elastomer and a thermosetting resin are preferable, and a reactive elastomer is more preferable. By using such a resin in combination with a curing agent, the peelability can be further improved and the mold flash characteristics can be enhanced.

The content of the resin in the adhesive layer is determined in consideration of the type of resin and the like. For example, it is preferably 80 to 98% by mass, and more preferably 85 to 95% by mass. If the content is less than the above lower limit, the adhesive strength may become insufficient and the mold flash characteristics may deteriorate. If the content exceeds the upper limit value, the content of the fluorine-containing additive becomes too small and the peelability may deteriorate.

The content of the reactive elastomer in the resin is, for example, preferably 50% by mass or more, and more preferably 80% by mass or more.

When a reactive elastomer or a thermosetting resin is used as the resin, a curing agent may be added to the adhesive layer.

The curing agent is appropriately determined depending on the kind of the reactive elastomer or the thermosetting resin, and may be, for example, polyisocyanate.

The content of the curing agent in the adhesive layer is appropriately determined in consideration of the kinds of the curing agent, the reactive elastomer or the thermosetting resin, and is preferably 0.5 to 10 parts by mass per 100 parts by mass of the resin.

The adhesive layer may contain an optional component such as a curing accelerator or an antioxidant within a range that does not adversely affect the effect of the present invention.

The adhesive layer has a surface fluorine recovery of 70% or more as determined by the formula (I) as described below.

The surface fluorine recovery rate of the adhesive layer is preferably 80% or more, more preferably 90% or more, and may be 100% or more. When the surface fluorine recovery rate is not less than the above lower limit value, excellent peelability can be exhibited. If the surface fluorine recovery rate is not lower than the lower limit value described above, it is not necessary to add an excessive fluorinated additive to the adhesive layer, so that the adhesive strength before curing becomes appropriate, and the adhesiveness to the lead frame or the wiring board So that the workability is improved.

In addition, the surface fluorine recovery rate is controlled by combining the kind or amount of the fluorine-containing additive and the kind or amount of the resin.

Surface fluorine recovery rate (%) = surface fluorine content after recovery? / Initial surface fluorine content rate 占 100 (I)

In the formula (I), the surface fluorine content after restoration? Is a value obtained by treating the adhesive layer with plasma at an output condition of 450 W for 1 minute under an argon gas atmosphere and then heating the adhesive layer at 220 占 폚 for 15 minutes Of fluorine (atom%). The initial surface fluorine content ratio? Is the fluorine content (atom%) of the surface of the adhesive layer before the plasma treatment.

The surface fluorine content? After the restoration is preferably 18 atomic% or more, more preferably 20 atomic% or more. Below the lower limit, there is a fear that the peelability of the adhesive sheet is lowered.

The initial surface fluorine content β is preferably 50 atom% or less, more preferably 30 atom% or less. If the upper limit is exceeded, the adhesive strength before curing becomes insufficient, and the adhesiveness to the lead frame or the wiring board is deteriorated in an adhering step to be described later.

In the adhesive sheet having the thermosetting adhesive layer containing the reactive elastomer, the thermosetting resin and the curing agent, the adhesive strength of the adhesive layer before the thermosetting to the lead frame or the wiring board at 25 캜 (adhesive strength before curing) was 0.05 N / 20 mm or more is preferable. If the adhesive strength before curing is the lower limit value or more, the adhesive layer is adhered to the lead frame or the wiring board with an appropriate bonding strength without thermosetting. Therefore, it is not necessary to heat the adhesive layer in the adhesion step described later, and the adhesion step can be simplified. The upper limit of the bonding strength at 25 캜 to the lead frame or the wiring board is not particularly limited.

An inorganic or organic filler may be added to the adhesive layer in order to adjust the thermal expansion coefficient, thermal conductivity, surface wrinkle, adhesiveness, etc. of the adhesive layer. Examples of the inorganic filler include pulverized silica, soluble silica, alumina, titanium oxide, beryllium oxide, magnesium oxide, calcium carbonate, titanium nitride, silicon nitride, boron nitride, titanium boride, tungsten boride, silicon carbide, titanium carbide A filler composed of zirconium, molybdenum carbide, mica, zinc oxide, carbon black, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, antimony trioxide or the like or a material obtained by introducing a trimethylsiloxane group into the surface of these materials . Examples of the organic filler include fillers composed of polyimide, polyamideimide, polyetheretherketone, polyetherimide, polyesterimide, nylon, silicone resin and the like.

The thickness of the adhesive layer is not particularly limited, but is, for example, 2 to 20 占 퐉.

The adhesive sheet can be configured so that a peelable protective film is adhered on the adhesive layer and the protective film is peeled off immediately before being adhered to the lead frame, the wiring substrate, or the like. In this case, the adhesive layer is prevented from being damaged until the adhesive sheet is manufactured and then used. The protective film may be any film having a releasing property, and examples thereof include films such as polyester, polyethylene, polypropylene, and polyethylene terephthalate, and films obtained by subjecting the surface of such films to a releasing treatment with a silicone resin or a fluorine compound Type processed film) or the like.

Examples of the method for producing the adhesive sheet include a casting method in which an adhesive is applied and dried on a substrate, a lamination method in which an adhesive is once coated on a releasable film, dried, and then transferred onto a substrate. Furthermore, the components constituting the adhesive layer may be dissolved in an organic solvent such as an aromatic solvent such as toluene, xylene and chlorobenzene, a ketone solvent such as acetone, methyl ethyl ketone or methyl isobutyl ketone, a dimethylformamide, dimethylacetamide, Methylpyrrolidone, N-methylpyrrolidone, tetrahydrofuran, or the like, or as a solution for applying an adhesive.

The method for manufacturing a semiconductor using the adhesive sheet of the present invention is a method for manufacturing a semiconductor using an adhesive sheet comprising a bonding step of bonding an adhesive sheet to a lead frame or a wiring board, a plasma cleaning step of treating the lead frame or the wiring substrate with plasma, And a peeling step of peeling the adhesive sheet from the lead frame or the wiring board after the heating step and the heating step.

Hereinafter, an example of a method of manufacturing a semiconductor device using the adhesive sheet of the present invention will be described with reference to Figs. 1 and 2. Fig. Fig. 1 is a plan view of a lead frame viewed from a side where semiconductor elements are mounted. Fig. 2 (a) - (f) are process drawings showing a method of manufacturing a QFN package using the lead frame shown in Fig. Sectional view taken along line A-A 'of FIG.

In the following description, an example is described in which a QFN package to which a lead frame is adhered is manufactured by using an adhesive sheet having a thermosetting adhesive layer containing a fluorine-containing additive, a reactive elastomer and a curing agent do.

The semiconductor device manufacturing method according to the present embodiment is characterized in that the semiconductor device manufacturing method according to the present embodiment includes a bonding step of bonding an adhesive sheet to a lead frame, a diamond touch step of mounting a semiconductor element on a lead frame, a plasma cleaning step of treating the lead frame with a plasma, A heating step of heating the adhesive layer of the adhesive sheet, a sealing step of sealing the semiconductor element with the sealing resin, a peeling step of peeling the adhesive sheet from the lead frame to obtain a QFN unit, and a QFN unit And a dicing step of obtaining a QFN package. Further, the heating process for heating the adhesive layer of the adhesive sheet may be included in the wire bonding process.

First, a lead frame 20 having a schematic configuration shown in Fig. 1 is prepared. The lead frame 20 includes a plurality of semiconductor element mounting portions (die pad portions) 21 on which semiconductor elements such as IC chips are mounted in a matrix form, and a plurality of leads 22).

As the material of the lead frame 20, conventionally known materials may be used, and for example, a nickel plating layer, a palladium plating layer and a gold plating layer may be successively provided on the surface of the copper plate.

)하도록 리드 프레임(20)의 한쪽 면(아래쪽 면)에 접착 시트(10)를 첩착한다(첩착 공정). 접착 시트(10)를 리드 프레임(20)에 첩착하는 방법으로는 라미네이트법 등이 매우 적합하다. 이 때, 리드 프레임(20)에 접착제층이 당접한 상태로 접착제층을 임의의 온도로 가열할 수도 있다. 이 가열에 의해 접착제층이 경화되고, 리드 프레임(20)에 접착 시트(10)가 보다 강고하게 첩착된다. 또한, 접착제층의 경화 전 접착 강도가 충분한 경우에는 첩착 공정으로 접착제층을 가열하는 대신, 후술하는 다이아터치 공정으로 가열 처리함으로써 접착제층을 경화할 수도 있다. 반도체 장치의 생산성을 높이는 관점에서는, 다이아터치 공정으로 접착제층을 경화하는 것이 바람직하다.As shown in Fig. 2 (a), an adhesive layer (not shown) contacts the lead frame 20

The adhesive sheet 10 is attached to one side (lower surface) of the lead frame 20 (adhesion step). As a method of attaching the adhesive sheet 10 to the lead frame 20, a lamination method and the like are very suitable. At this time, the adhesive layer may be heated to an arbitrary temperature in a state in which the adhesive layer is in contact with the lead frame 20. By this heating, the adhesive layer is hardened, and the adhesive sheet 10 is adhered to the lead frame 20 more firmly. When the adhesive strength before curing of the adhesive layer is sufficient, the adhesive layer may be cured by heat treatment in a later-described die-touch process, instead of heating the adhesive layer in the adhesive process. From the viewpoint of enhancing the productivity of the semiconductor device, it is preferable to cure the adhesive layer by a diapot process.

An IC chip or the like is attached to the semiconductor element mounting portion 21 of the lead frame 20 on the side where the adhesive sheet 10 is not adhered, And the semiconductor element 30 is placed thereon. Thereafter, the diaphragm is hardened by heating at about 100 to 200 ° C, and the semiconductor element 30 is fixed to the semiconductor element mounting portion 21 (diamond touch-hardening treatment or more, diamond touch step). Here, the fluorine-containing additive in the adhesive layer is heated on the surface of the adhesive layer by the adhesion process or the diap touch process.

If an outgas component generated from the adhesive sheet 10 or the diazotizer is adhered to the lead frame 20 or the semiconductor element 30, it is likely to cause reduction in hold due to wire bonding failure in the wire bonding step. Thus, after the diamond touch process and before the wire bonding process, the lead frame 20 and the semiconductor element 30 are subjected to plasma treatment (plasma cleaning process). As the plasma processing, for example, a lead frame 20 (hereinafter referred to as a product under production) on which an adhesive sheet 10 is adhered and on which a semiconductor element 30 is mounted is filled with argon gas or argon gas and hydrogen gas A mixed gas of argon gas and argon gas. The output power of the plasma in the plasma treatment is, for example, 150 to 600 W. The time of the plasma treatment is, for example, 0.01 to 5 minutes.

When the plasma is treated, the adhesive layer cuts the surface layer in which the fluorine-containing additive is localized, and the amount of the fluorine-containing additive on the surface of the adhesive layer decreases. At this time, on the surface of the adhesive layer, the amount of the fluorine-containing additive for improving the peelability becomes insufficient, and the peelability of the adhesive sheet 10 is lowered.

The semiconductor element 30 and the lead 22 of the lead frame 20 are electrically connected to each other by a bonding wire 31 such as a gold wire as shown in Fig. 2 (c) (wire bonding step). This process is performed by heating the product to 150 to 250 ° C on the heater block. The heating time in this step is, for example, 5 to 30 minutes. In the present embodiment, the wire bonding process also serves as a heating process for heating the adhesive layer.

When the product is heated during the wire bonding process, the fluorine-containing additive dispersed in the adhesive layer migrates to the surface of the adhesive layer. Here, since the surface fluorine recovery ratio of the adhesive layer is 70% or more, the amount of the fluorine-containing additive on the surface of the adhesive layer is sufficient to increase the peelability. In the peeling step to be described later, the adhesive sheet 10 is easily peeled off from the lead frame 20 and the sealing resin 40.

As shown in Fig. 2 (d), the product during the production shown in Fig. 2 (c) is placed in a metal mold and transfer molding (mold molding) is performed using an encapsulating resin (molding material) Is sealed with a sealing resin 40 (sealing step). As the encapsulating resin, conventionally known ones may be used, for example, a mixture of an epoxy resin and an inorganic filler.

The adhesive sheet 10 is peeled from the sealing resin 40 and the lead frame 20 to obtain a QFN unit 60 in which a plurality of QFN packages 50 are arranged as shown in Figure 2 (e) Peeling process). At this time, since the additive containing fluorine is present in a sufficient amount on the surface of the adhesive layer, the adhesive sheet 10 can be easily peeled off from the lead frame 20 and the sealing resin 40.

As shown in Fig. 2 (f), the QFN unit 60 is diced along the outer periphery of each QFN package 50 to obtain a plurality of QFN packages 50 (dicing step).

As described above, the semiconductor device such as the QFN package is manufactured by using the adhesive sheet 10 of the present embodiment, so that the adhesive sheet 10 is prevented from adhering to the lead frame 20 and the sealing resin 40 ). Therefore, the productivity of the semiconductor device can be increased by increasing the working efficiency, and the defect of the semiconductor device due to the residual adhesive can be prevented.

Further, in the above-described embodiments, a method of manufacturing a QFN package using a lead frame is described as an example. However, the present invention is not limited to this, and a semiconductor device manufacturing method other than a QFN package using a lead frame, Can also be applied.

For example, the heating process for heating the adhesive layer may be performed between the plasma cleaning process and the wire bonding process, or between the wire bonding process and the wire bonding process. And may be performed independently during the sealing process.

The heating temperature in the heating step is determined depending on the kind of the fluorine compound or the like and is, for example, about 150 to 250 캜. The heating time in the heating step is determined depending on the kind of the fluorinated compound, and is, for example, 5 to 30 minutes.

[Example]

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

(Raw materials used)

≪ Additive containing fluorine >

MEGAFAC F-554: Nonionic surfactant which is an oligomer containing fluorine group and lipophilic group, liquid at 25 占 폚, manufactured by DIC Corporation.

MODIPER F600: a block copolymer of methacrylic acid ester and alkyl acrylate fluoride, solid at 25 占 폚, powder;

≪ Reactive elastomer &

S / EB ratio = 20/80, acid value = 10 mg CH ₃ ONa / g, manufactured by Ushiku Chemical Industries Co., Ltd., TUFTEC M-1943: SEBS containing maleic anhydride, S / EB ratio =

Tuftec M-1911: SEBS containing maleic anhydride, S / EB ratio = 30/70, acid value = 2 mg CH ₃ ONa / g, manufactured by Ukika Chemicals Corporation.

<Other Resins>

LUMIFLON LF200F: fluorine-containing thermosetting resin, manufactured by Wako Co., Ltd.

<Curing agent>

DURANATE TSA-100: Isocyanate, manufactured by Ukika Chemicals & Co., Ltd.

<Antioxidant>

IRGANOX 1010FF: manufactured by BASF.

SUMILIZER GS (F): manufactured by ZU Chemical Co., Ltd.

(Examples 1 to 3 and Comparative Examples 1 to 4)

According to the composition shown in Table 1, each raw material was dispersed in an appropriate amount of toluene to prepare an adhesive coating liquid.

Next, a polyimide resin film (trade name: KAPTON 100 EN, thickness 25 占 퐉, glass transition temperature 300 占 폚 or higher, thermal expansion coefficient 16 ppm / 占 폚 manufactured by Toray DuPont Co., Ltd.) The above-mentioned adhesive coating liquid was applied so that the thickness after drying was 5 占 퐉. The adhesive coating liquid was applied and then dried at 150 DEG C for 3 minutes to obtain an adhesive sheet of each example. On the obtained adhesive sheet, the surface fluorine content and the adhesive strength were measured, and the presence or absence of the mold flash and the residual adhesive were evaluated.

(How to measure)

&Lt; Measurement of surface fluorine content &gt;

The adhesive sheet of each example was placed in a thermostat (Perfect Oven PHH-201, manufactured by ESPEC) and heated at 175 占 폚 for 1 hour to cure the adhesive layer. The surface fluorine content of the cured adhesive layer was measured according to the &quot; method for measuring the surface fluorine content &quot;

Next, the adhesive sheet was placed in a plasma cleaner (YES-G1000, manufactured by YIELD ENGINEERING SYSTEM) with the adhesive layer facing up. Under an argon gas atmosphere (atmosphere of argon gas 100 mass% The layer was treated with plasma for 1 minute. The surface fluorine content of the adhesive layer immediately after the plasma treatment was measured in accordance with the &quot; Method of measuring the surface fluorine content &quot; described later, and the surface fluorine content after the plasma treatment was determined.

The adhesive sheet was placed on a hot plate (EC-1200, made by Nippon Kayaku Co., Ltd.) with the plasma-treated adhesive layer facing up, and heated at 220 占 폚 for 15 minutes. After the completion of the heating, the substrate was allowed to stand at 25 占 폚 for 24 hours, and then the surface fluorine content of the adhesive layer was measured according to the &quot; method for measuring the surface fluorine content &quot;

&Quot; Method of measuring surface fluorine content &quot;

The surface of the adhesive layer was measured under the following conditions using a scanning X-ray photoelectron spectroscopic analyzer (XPS / ESCA, Quantera SXM, manufactured by ULVAC · PHI Co., Ltd.). The surface fluorine content (atom%) is expressed as a content ratio of 100 atom% of the total of carbon, nitrogen, oxygen, fluorine, silicon and gold. In addition, no silicon or money was detected in the measurement of the surface fluorine content in each example.

Measuring conditions

X-ray source: monochromatic AlK alpha

X-ray output: 25. 0W

X-ray irradiation diameter: φ100 μm

Measurement area: Point 100 탆

Optoelectronic Congestion Angle: 45deg

WideScan: 280.0e; 1.000eV / Step

<Measurement of Adhesive Strength>

(32 QFN (CD194, plated; PD2L + Au) 32 LQFNPADSIZE 3.0 SQMM, manufactured by Shin Kwang Electric Industry Co., Ltd.) having a nickel plating layer, a palladium plating layer and a gold plating layer sequentially arranged on a copper plate was used as a lead frame Respectively. Each example of the adhesive sheet was cut into a size of 50 mm x 60 mm by using a paper cutter (paper press NS type, an abrasion-inducing agent). The adhesive sheet cut at 25 DEG C at a speed of 1.0 m / min and at a pressure of 0.37 N / mm was adhered to a lead frame using a tablet laminator (MAII-700, manufactured by DASON LAMINATE CO., LTD. ). In addition, in Example 3, Comparative Example 1, and Comparative Example 4, adhesion to a lead frame was carried out at 80 占 폚 because adhesion at 25 占 폚 was insufficient.

The lead frame to which the adhesive sheet was adhered was placed in a thermostat (Perfect Oven PHH-201, manufactured by Espec Co., Ltd.) and heated at 175 占 폚 for 1 hour to cure the adhesive layer (corresponding to the diaphragm- .

Then, the adhesive sheet was placed in a plasma cleaner (YES-G1000, manufactured by YIELD ENGINEERING SYSTEM) with the adhesive layer facing up, and the adhesive layer was subjected to a plasma treatment for 1 minute under an output condition of 450 W under an argon gas atmosphere (Plasma cleaning process).

After the plasma cleaning process, the lead frame to which the adhesive sheet was adhered was placed in a hot plate (EC-1200, made by Nippon Kayaku Co., Ltd.) with the adhesive sheet facing downward and heated at 220 占 폚 for 15 minutes (equivalent to the wire bonding process).

After completion of the wire bonding process, the lead frame, to which the adhesive sheet was adhered, was bonded to the sealing resin using a transfer molding press (TEP12-16, manufactured by Kyowa Precision Machinery Co., Ltd.) at a heating temperature of 175 占 폚, a resin pressure of 69 MPa, (KMC-3520 L, manufactured by Shin-Etsu Chemical Co., Ltd.) (sealing process). After the sealing step, the sample was allowed to stand at 25 占 폚 for 24 hours, and then the bonding strength with the lead frame was measured after resin sealing according to the &quot; method of measuring the bonding strength with the lead frame after resin sealing &quot;

Lead frame specification

Outside dimension: 55mm × 58mm

Application: For QFN

Array of QFNs: 8 × 8 (64 total) matrix arrays

Package size: 5mm × 5mm

Number of Pins: 32

&Quot; Method of measuring bonding strength with lead frame after resin sealing &quot;

A tensile test was carried out at a measuring temperature of 25 DEG C, a peeling angle of 90 DEG and a peeling rate of 50 mm / min using a universal tensile tester (AGS-100B, manufactured by Tojin Co., Ltd.) Respectively.

<Method of Measuring Adhesive Strength before Curing>

(20 mm in width) was laminated on a copper plate (copper strike or gold plate ELA601, 25 mm x 100 mm, manufactured by Shin Kwang Denki Kogyo K.K.) using a tabletop laminator (MAII-700, Daesung Laminator Co., Ltd.) = 1.0 m / min, and the pressure was 0.37 N / mm, and used as a measurement sample. The tensile test was carried out on this measured sample using a universal tensile tester (AGS-100B, manufactured by TOJIN CO., LTD.) At a measuring temperature of 25 DEG C, a peeling angle of 90 DEG and a peeling rate of 50 mm / Respectively. In addition, for Example 3, a sample which was attached to a copper plate at 80 占 폚 was used as a measurement sample since the adhesiveness at 25 占 폚 was insufficient.

<Presence of mold flash generation>

After measuring the adhesive strength, the adhesion surface of the adhesive sheet in the lead frame was observed with an optical microscope (digital microscope VHX-500, manufactured by KEYENCE Co., Ltd.) to determine whether or not the mold flash occurred Respectively. In the table, the number of QFN packages for which the mold flash is recognized among one lead frame (64 QFN packages) is described.

<Presence of adhesive residue>

In the &quot; Measurement of Adhesive Strength &quot;, the adhesive strength was measured, and after the resin sealing, the presence or absence of the adhesive remained on the lead frame was confirmed by an optical microscope (digital microscope VHX-500, manufactured by KEYENCE CORPORATION). In the table, the number of QFN packages in which adhesive residue is recognized among one lead frame (64 QFN packages) is described.

As shown in Table 1, it was confirmed that the surface fluorine content in each example decreased by the plasma cleaning process.

Examples 1 to 3 in which the present invention was applied showed that the adhesive strength to the lead frame after resin sealing was 15 N / 50 mm or less, and that the peeling was easily possible. Furthermore, in all of Examples 1 to 3, mold flash generation and adhesive remnants were not observed.

On the other hand, in Comparative Examples 1 to 4, in which the surface fluorine recovery ratio was less than 70%, the bonding strength with the lead frame after resin sealing was larger than 15 N / 50 mm and was difficult to peel off.

From these results, it was confirmed that the present invention can exert excellent releasability in the peeling process.

10: Adhesive sheet for semiconductor device manufacturing
20: Lead frame
30: Semiconductor device
31: Bonding wire
40: sealing resin
50: QFN package

Claims (3)

materials; And an adhesive layer containing a fluorine-containing additive provided on one side of the substrate, wherein the adhesive sheet is peelably adhered to (adhered to) a lead frame or a wiring board of a semiconductor device,
Wherein the adhesive layer has a surface fluorine recovery of 70% or more as determined by the following formula (I).
Surface fluorine recovery (%) = Surface fluorine content after restoration α ÷ Initial surface fluorine content β × 100 ... (I)
In the formula (I), the surface fluorine content after restoration? Was treated in an argon gas atmosphere under an output condition of 450 W for 1 minute under an argon gas atmosphere, and then the adhesive layer was heated at 220 占 폚 for 15 minutes to form an adhesive layer surface Of fluorine (atom%). The initial surface fluorine content ratio? Is the fluorine content (atom%) of the surface of the adhesive layer before the plasma treatment.
The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the surface fluorine content after restoration α is 18 atom% to 50 atom%.
A method of manufacturing a semiconductor device using an adhesive sheet for manufacturing a semiconductor device according to claim 1 or 2,
A bonding step of bonding the adhesive sheet for semiconductor device production to the lead frame or the wiring board;
A plasma cleaning process for treating the lead frame or the wiring board with plasma;
A heating step of heating the adhesive layer after the plasma cleaning step; And
And a peeling step of peeling off the adhesive sheet for manufacturing the semiconductor device from the lead frame or the electric wiring substrate after the heating step.

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