TWI528467B - Pressure-sensitive adhesive tape for resin encapsulation and method for producing resin encapsulation type semiconductor device - Google Patents

Description

Pressure-sensitive adhesive tape for resin encapsulation and method for manufacturing resin-encapsulated semiconductor device Field of invention

The present invention relates to a pressure-sensitive adhesive tape for resin encapsulation and a method for producing a resin-encapsulated semiconductor device.

Background of the invention

In recent years, CSP (Chip Size/Class Package) technology is well known in LSI mounting technology. In this technique, the lead terminals are included in a package in a package - represented by QFN (Quad Flat No-Lead Package) - especially when it comes to size reduction and high integration.

In such QFNs, the preparation methods which significantly increase the yield of each lead frame region are particularly well known. Such methods include the following methods of preparing a plurality of wafers for QFN on a die pad die, encapsulating them in a mold cavity with an encapsulating resin, and then cutting them, To be divided into individual QFN structures.

In the QFN preparation method, in which a plurality of semiconductor wafers are entirely encapsulated, an area sandwiched by the resin-encapsulated molding die is only a portion of the outer portion of the resin-encapsulated region completely covering the package pattern region. Therefore, in the package pattern region, particularly in the central portion thereof, the back surface of the lead frame cannot be pressed down to the molding die with sufficient pressure, so it is difficult to prevent the encapsulation resin from leaking to the back surface of the lead frame. As a result, the problem that the terminal or the like of the QFN is covered with the resin easily occurs.

To this end, the pressure-sensitive adhesive tape is adhered to the back of the lead frame and the sense of use The self-adhesive sealing effect of the pressure-sensitive adhesive tape to prevent the resin from leaking to the back surface of the lead frame is effective for the preparation method of QFN.

Here, in terms of operational characteristics, it is substantially difficult to adhere the heat-resistant pressure-sensitive adhesive tape to the back surface of the lead frame after the semiconductor wafer is mounted on the lead frame or after wire bonding. Therefore, it is desired to adhere the heat-resistant pressure-sensitive adhesive tape to the back surface of the lead frame, and after bonding with the wire by mounting the semiconductor wafer, the resin is encapsulated with an encapsulating resin, and then the heat-resistant pressure-sensitive adhesive tape is peeled off. A method of performing a series of wire bonding and the like while using a heat-resistant pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer having a thickness of 10 μm or less to prevent resin leakage has been proposed as an example of such a method (for example Said, JP-A-2002-184801).

Summary of invention

In the above preparation method, in addition to the property of avoiding leakage of the encapsulating resin, the pressure-sensitive adhesive tape is also required to have a high heat resistance enough to resist the heat of the semiconductor wafer mounting step without adversely affecting the fineness of the wire bonding step. Operating characteristics and excellent peeling ability after resin encapsulation.

It is difficult to meet all of these needs. In particular, in recent years, various types of diversified QFN preparation methods (especially MAP type preparation, in which a large number of packages are completely encapsulated), the pressure-sensitive adhesive tape is affected by the thermal history, and the pressure-sensitive adhesive tape avoids encapsulation of the resin. The certainty of resin leakage is lowered and the pressure-sensitive adhesive tape adversely affects the condition of wire bonding certainty.

In view of the above, it is highly resistant to resin leakage and even under severe conditions, such as MAP-QFN processes, does not adversely affect wire bonding, and has a tree A heat-resistant pressure-sensitive adhesive tape having excellent peeling ability after being encapsulated is required.

The present invention has been made in view of the above problems.

Accordingly, it is an object of the present invention to provide a heat resistance which is highly resistant to resin leakage and which does not adversely affect wire bonding certainty even under severe conditions such as MAP-QFN process, and which has excellent peeling ability after resin encapsulation. Pressure adhesive tape.

Another object of the present invention is to provide a method of manufacturing a semiconductor device using the pressure-sensitive adhesive tape.

In order to achieve the above object, the inventors of the present invention have found that the above object can be achieved by using a glass transition temperature (Tg) in a specific temperature region through various investigations on the characteristics, materials, thickness, and the like of the heat-resistant pressure-sensitive adhesive tape. The base material layer is achieved and has been completed to complete the present invention.

That is, the present invention provides a pressure-sensitive adhesive tape for resin encapsulation in the manufacture of a resin-encapsulated semiconductor device, the pressure-sensitive adhesive tape comprising: a base material layer which does not have 260 ° C or more a glass transition temperature in a low temperature region; and a pressure-sensitive adhesive layer laminated on the base material layer.

It is preferred that the base material layer does not have a glass transition temperature in a temperature range of 300 ° C or lower.

Preferably, the base material layer has a thickness of 5 to 100 μm.

It is preferred that the base material layer has a heat shrinkage of 0.40% or less when heated at 180 ° C for 3 hours.

Preferably, the pressure-sensitive adhesive layer is laminated only to the base material layer. On one side.

Preferably, the pressure-sensitive adhesive layer has a thickness of from 2 μm to 50 μm.

It is preferable that the ratio (B/A) of the pressure-sensitive adhesive layer thickness (B) to the base material layer thickness (A) is 3 or less.

Preferably, the thermogravimetric analysis is carried out under the measurement conditions of a temperature rise rate of 10 ° C / min, atmospheric gas is air, and a gas flow rate of 200 ml / min, and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer has 250 5% weight loss temperature of °C or higher.

It is preferable that the amount of gas generated by heating the pressure-sensitive adhesive constituting the pressure-sensitive adhesive tape at 200 ° C for 1 hour is 1.0 mg / g or less.

Preferably, at a 180° peel angle, the pressure-sensitive adhesive tape has an adhesion of 0.05 to 6.0 N/19 mm width to the lead frame.

Preferably, it is heated at 200 ° C for 1 hour, cooled to normal temperature, and peeled at an angle of 180 ° - the pressure-sensitive adhesive tape has an adhesion of 0.1 to 6.0 N / 19 mm width to the lead frame.

Preferably, at a 180° peel angle, the pressure-sensitive adhesive tape has an adhesion of 10.0 N/19 mm width or less to the encapsulating resin.

It is preferred that the pressure-sensitive adhesive layer has a storage modulus of -0.50 x 10 ⁵ Pa or more at 200 °C.

It is preferable that the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is a silicone pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, or a rubber pressure-sensitive adhesive.

It is preferable that the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer has a gel fraction of 60% or more.

Preferably, the pressure-sensitive adhesive tape further comprises a release sheet in contact with the pressure-sensitive adhesive layer, the release sheet meeting at least one of the following requirements (a) to (d): (a) at a peeling angle of 90 The peel strength of °±15° is 1.5 N/50 mm width or less, (b) the peel strength at the peel angle of 120°±15° is 1.2 N/50 mm width or less, and (c) the peel angle 150 The peel strength of ±15° is 1.0 N/50 mm width or less, and (d) the peel strength at the peel angle of 180°+0° and 180°-15° is 1.0 N/50 mm width or less.

Preferably, the pressure-sensitive adhesive tape is a method for manufacturing a resin-encapsulated semiconductor device, the method comprising: adhering a pressure-sensitive adhesive tape to a metal lead frame having a terminal portion and a die pad The surface is opposite to the metal lead frame surface on which the die pad is disposed; the semiconductor wafer die having the electrode pad is bonded to the die pad of the metal lead frame; and the bonding wire is electrically connected a tip end of the metal lead frame terminal portion and an electrode holder on the semiconductor wafer; and a metal lead frame surface on which the semiconductor wafer is disposed with the encapsulating resin.

Further, the present invention provides a method for manufacturing a resin-encapsulated semiconductor device, the method comprising: Adhering the above-mentioned pressure-sensitive adhesive tape of the present invention to one side of a metal lead frame having a terminal portion and a die pad, the surface being opposite to a metal lead frame surface on which a die pad is disposed; and a semiconductor wafer crystal having an electrode holder The particles are bonded to the die pad of the metal lead frame; the tip of the terminal portion of the metal lead frame is electrically connected to the electrode pad on the semiconductor wafer by the bonding wire; and the metal lead frame surface on which the semiconductor wafer is disposed with the encapsulating resin .

In the present specification, unless otherwise indicated, the expression "X to Y (where X and Y are numerical values)" of the numerical range is used to mean that the numerical range includes values representing both ends (ie, including X and Y). .

The pressure-sensitive adhesive tape according to the present invention is highly resistant to resin leakage and does not affect the wire bonding certainty even under severe conditions, for example, in the MAP-QFN process, and has excellent peeling ability after resin encapsulation.

Further, according to the method of manufacturing a semiconductor device according to the present invention, even if the method is applied to a MAP-QFN process, resin leakage is difficult to occur, wire bonding is highly determinable, and it is easily peeled off for resin package after resin encapsulation. Sealed pressure-sensitive adhesive tape.

Simple illustration

1A to 1F are flowcharts showing a process of an example of a method of fabricating a semiconductor device according to the present invention.

2A is a plan view showing an example of a lead frame used in a method of fabricating a semiconductor device according to the present invention, and FIG. 2B is a view showing a main portion of the lead frame. Big picture.

The best mode of invention Base material layer

The pressure-sensitive adhesive tape of the present invention comprises a base material layer which does not have a glass transition temperature in a temperature region of 260 ° C or lower.

The pressure-sensitive adhesive tape for resin encapsulation in the preparation of the resin-encapsulated semiconductor device is exposed to a high temperature in use. In particular, the pressure-sensitive adhesive tape is generally exposed to a high temperature of about 200 ° C in the wire bonding step.

The pressure-sensitive adhesive tape of the present invention comprises a base material layer which does not have a glass transition temperature in a temperature region of 260 ° C or lower. Therefore, the pressure-sensitive adhesive tape is highly resistant to resin leakage and does not affect the wire bonding certainty even under severe conditions such as the MAP-QFN process, and has excellent peeling ability after resin encapsulation.

According to the investigation by the inventors of the present invention, unexpectedly, even in the case where the base material layer does not have a glass transition temperature of about 200 ° C at the above-mentioned wire bonding temperature, resin leakage occurs in the resin encapsulation step and is subjected to thermal history. The influential pressure-sensitive adhesive sheet affects several cases of wire bonding certainty.

Preferably, the base material layer does not have a glass transition temperature in a temperature range of 300 ° C or lower.

The base material layer is not particularly limited as long as it does not have the glass transition temperature in the above temperature range, and it is possible to use any base material layer as long as it is a base material layer of the pressure-sensitive adhesive tape used in the art. The material used can be composed.

Examples of such materials include polyether oxime (PES) resins, polyether phthalimide (PET) resins, polyfluorene (PSF) resins, polyetheretherketone (PEEK) resins, polyarylate (PAR) resins, and aromatics. A guanamine resin, a polyimide resin, a liquid crystal polymer (LCP), and a metal foil such as an aluminum foil.

Among them, a polyimide resin is preferably used from the standpoint of heat resistance and strength of a base material.

In the present specification, the term "glass transition temperature" means the temperature at which the loss tangent (tan δ) peak is confirmed by the DMA method (stretching method) under the following conditions, the temperature rise rate: 5 ° C / min, sample width: 5 mm, chuck distance: 20 mm and frequency: 10 Hz. The glass transition temperature is measured by a commercially available equipment (for example, RSA-II, manufactured by Rheometric Scientific FE Ltd.). Thus, for example, the expression "glass transition temperature in a temperature region not having a temperature of 260 ° C or lower" means that no loss tangent (tan δ) peak is observed in a temperature region of 260 ° C or lower.

The base material layer has a thickness of preferably 5 μm or more, more preferably 10 μm or more in terms of the operational characteristics of the pressure-sensitive adhesive tape (for example, it is difficult to cause the tape to be bent or torn). On the other hand, the base material layer has a thickness of preferably 100 μm or less, more preferably 75 μm or less, in terms of the peeling ability of the pressure-sensitive adhesive tape.

In terms of avoiding the warpage of the lead frame due to shrinkage of the base material layer, the base material layer preferably has a heat shrinkage of -3 to -40% or less at 180 °C.

In the present specification, the term "heat shrinkage" is measured as follows. that is, The 5 cm square film was heated at 180 ° C for 3 hours and taken as a "heat shrinkage" in a spatial change ratio (%) with respect to the size (5 cm square) before heating (100% square). The shrinkage is measured by a commercially available projector (PJ-H3000F, manufactured by Mitsutoyo Corporation).

Pressure sensitive adhesive

The pressure-sensitive adhesive tape has a pressure-sensitive adhesive layer laminated on the base material layer. Here, the pressure-sensitive adhesive layer may be disposed on only one side of the base material layer and may be disposed on both sides of the base material layer.

The pressure-sensitive adhesive layer is preferably laminated on only one side of the base material layer.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited as long as it has heat resistance, and may be any of pressure-sensitive, sensible, and photosensitive.

Examples of the pressure-sensitive adhesive include various pressure-sensitive adhesives such as an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, and an epoxy pressure-sensitive adhesive.

Among them, in terms of heat resistance, a silicone pressure-sensitive adhesive and an acrylic pressure-sensitive adhesive are preferably used, and a silicone pressure-sensitive adhesive is more preferably used.

Examples of the silicone pressure sensitive adhesive include a pressure sensitive adhesive containing dimethyl polyoxyalkylene.

Examples of the acrylic pressure-sensitive adhesive include a pressure-sensitive adhesive including an acrylic copolymer obtained by copolymerization of a monomer containing at least one alkyl (meth) acrylate. In the present specification, the term "alkyl (meth) acrylate" means an alkyl acrylate and/or an alkyl methacrylate.

Examples of the alkyl (meth) acrylate include methyl (meth) acrylate Ester, ethyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Ester, isooctyl (meth) acrylate, isodecyl (meth) acrylate, mercapto (meth) acrylate, and dodecyl (meth) acrylate. Wherein, a copolymer of an acrylic monomer and a 2-ethylhexyl (meth) acrylate monomer, and a methyl (meth) acrylate and/or an ethyl (meth) acrylate, an acrylic monomer, and 2-B Copolymers of hexyl-based (meth) acrylate monomers are preferred.

The pressure-sensitive adhesive layer may contain a crosslinking agent if necessary.

Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine compound, and a chelate crosslinking agent.

The amount of the crosslinking agent to be added is not particularly limited. For example, in the case of using an acrylic pressure-sensitive adhesive, the amount of the crosslinking agent added is preferably from 0.1 to 15 parts by weight, more preferably from 0.5 to 100 parts by weight per 100 parts by weight of the acrylic pressure-sensitive adhesive. 10 parts by weight. When the crosslinking agent is used in this range, the viscoelasticity of the pressure-sensitive adhesive layer can be appropriately set, and an appropriate adhesion of the pressure-sensitive adhesive layer to the lead frame or the encapsulating resin can be obtained. As a result, it is possible to avoid the phenomenon that the encapsulating resin is peeled off or broken even when the pressure-sensitive adhesive tape is peeled off, and a part of the pressure-sensitive adhesive layer is adhered to the lead frame or the encapsulating resin (that is, the adhesive residue). In addition, excessive curing of the pressure-sensitive adhesive layer can be suppressed.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer preferably has a gel fraction of 60% or more from the standpoint of peeling off the adhesive residue in the pressure-sensitive adhesive tape of the present invention.

Avoiding adhesive residue makes it possible to omit the cleaning step of the semiconductor wafer.

The gel fraction of the pressure-sensitive adhesive can be adjusted by, for example, adjusting the degree of crosslinking.

In the present specification, the term "gel fraction" means the proportion of the solvent-insoluble component in the pressure-sensitive adhesive, and is measured by the following method.

(measurement of gel fraction)

A pressure sensitive adhesive is applied to the surface of the release sheet or the like, followed by drying and curing. About 0.1 g of the pressure-sensitive adhesive film thus obtained was covered with a tetrafluoroethylene sheet, and immersed in an excess solvent (toluene) at room temperature for 1 week. The weight of the pressure-sensitive adhesive layer before and after the immersion was measured, and the ratio (weight after immersion/weight before immersion) x 100 was used as the gel fraction.

The pressure-sensitive adhesive layer may further include various additives conventionally used in the art, such as plasticizers, pigments, dyes, anti-aging agents, antistatic agents added to improve the characteristics of pressure-sensitive adhesive layers (for example, elastic modulus). Agents, and fillers. The amount of the additive to be added is not particularly limited as long as the appropriate adhesion of the pressure-sensitive adhesive layer is not impaired. The amount of the additive to be added is generally 0.5 to 20 parts by weight and preferably 1.0 to 15 parts by weight per 100 parts by weight of the total pressure-sensitive adhesive layer.

The pressure-sensitive adhesive layer is heated at 200 ° C for 1 hour from the standpoint of avoiding deterioration of wire bonding due to secondary settling of the generated gas on the surface of the lead frame and reducing the reliability of moisture resistance of the package after resin encapsulation. The amount of gas produced is preferably 1.0 mg/g or less.

The amount of gas generated can be reduced by, for example, increasing the degree of crosslinking of the pressure-sensitive adhesive and removing the low molecular weight component of the pressure-sensitive adhesive.

In this specification, the term "amount of gas produced" means the following The amount of gas produced (total outgassing, μg (gas) / g (pressure-sensitive adhesive layer)): 10 mg of pressure-sensitive adhesive layer was collected and encapsulated in a small glass bottle for gas chromatography, capturing The amount of gas generated is measured by gas chromatography by gas generated by heating.

The amount of gas produced can be measured by, for example, the following apparatus and conditions.

<Measurement device>

Headspace autosampler: "7694", manufactured by Aglilent Technologies

GC: "6890 Plus", manufactured by Aglilent Technologies

MS: "5973N", manufactured by Aglilent Technologies

<Measurement conditions>

(headspace autosampler)

Pressure time: 0.12 min

Loop priority time: 0.12 min

Loop balance time: 0.05 min

Injection time: 3.00 min

Sample loop temperature: 200 ° C

Transfer line temperature: 220 ° C

(GC)

Column: HP-5MS (0.25 μm), 0.25 mm diameter x 30 m

Carrier gas: He, 1.0 ml/min (fixed flow mode)

Column head pressure: 48.7 kPa (40 ° C)

Entrance: split (split ratio 46:1)

Inlet temperature: 250 ° C

Column temperature: 40 ° C (maintain 5 mm) - (+10 ° C / mm) -> 300 ° C (maintain 9 mm)

(MS)

Ionization method: EI

Emission current: 35 μA

Electronic energy: 70 eV

E.M. Voltage: 1141V

Source temperature: 230 ° C

Q-pole: 150 ° C

Interface: 280 ° C

In order to avoid the adhesive residue after the peeling tape is deteriorated due to the deterioration of the pressure-sensitive adhesive due to the semiconductor preparation step, such as the adhesion step during the semiconductor preparation step or the wire bonding, the pressure-sensitive adhesive is desired. The ground has a temperature loss of 5% by weight of 250 ° C or higher.

The 5% weight loss temperature can be increased by, for example, increasing the degree of crosslinking of the pressure-sensitive adhesive and removing the low molecular weight component of the pressure-sensitive adhesive.

The 5% weight loss temperature is measured at a temperature rise rate of 10 ° C / min, atmospheric gas: air and gas flow rate: 200 ml / min.

Specifically, the 5% weight loss temperature was measured by the following measurement method.

(Measurement methods)

Measurement item: TG (thermogravimetric method)

Measuring device: "TG/DTA 6200", manufactured by SII NanoTechnology Inc.

Measurement operation: The sample was placed in a platinum container, and TG measurement was performed under the following conditions, and the value at the time of 5% weight loss was measured.

Measurement conditions:

Measuring temperature zone: room temperature to 850 ° C

Temperature rise rate: 10 ° C / min

Atmospheric gas: air

Gas flow rate: 200 ml/min

The pressure-sensitive adhesive tape is sometimes adhered to the lead frame before the wire bonding step of electrically connecting the tip end portion of the lead frame to the electrode holder on the semiconductor wafer. In this case, the pressure-sensitive adhesive layer is too soft to obtain sufficient wire bonding ability. Therefore, the pressure-sensitive adhesive layer preferably has a storage modulus of from -200 ° C to 5.0 x 10 ⁴ Pa or more in terms of sufficient wire bonding ability.

On the other hand, the storage modulus is 1.0 x ^{10 7} Pa or less in terms of obtaining a suitable adhesive force.

In this specification, the term "storage modulus" is obtained by the following values: a sample layer having a thickness of 1.5 mm to 2 mm is prepared, and a sample layer is punched through a 7.9 mm diameter punch to obtain a sample, and A viscoelastic spectrometer (ARES) manufactured by Rheometric Scientific was measured at a chuck pressure of 100 g weight and a frequency of 1 Hz.

The pressure-sensitive adhesive layer has a thickness of preferably 2 μm or more, more preferably 3 μm or more, and further preferably 4 μm or more, from the standpoint of sufficient adhesion to the lead frame. On the other hand, in terms of sufficient wire bonding capability, the thickness is preferably 50 μm or less, more preferably 40 μm or less, and further The step is preferably 30 μm or less.

In the pressure-sensitive adhesive tape, the ratio of the pressure-sensitive adhesive layer thickness (B) to the base material layer thickness (A) (B/A) is preferably 3 or 3 in terms of suppressing the adhesive residue in the pressure-sensitive adhesive tape. less.

Method for preparing pressure-sensitive adhesive tape

The pressure-sensitive adhesive tape of the present invention can be produced by a conventional manufacturing method in the art. For example, the pressure-sensitive adhesive layer component described above is prepared and applied to one side of the base material layer, followed by drying. Thus, a pressure-sensitive adhesive layer can be formed. As a coating method of the pressure-sensitive adhesive layer component, various methods such as coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, and the like can be applied. Mold coating, dip coating, offset printing, flexo printing and screen printing. A method of separately forming a pressure-sensitive adhesive layer on the release liner and adhering the pressure-sensitive adhesive layer to the base material film may also be used.

Pressure sensitive adhesive tape

The pressure-sensitive adhesive tape of the present invention thus obtained is adhered to the lead frame when the resin-encapsulated semiconductor device is manufactured, and therefore it is necessary to have appropriate pressure-sensitive adhesiveness to the lead frame.

In terms of having sufficient adhesion to the lead frame (for example, the adhesion of the tape peeling during the process), the pressure-sensitive adhesive tape has a peel angle of 180° to the lead frame (especially described later) A lead frame formed of a metal plate) preferably has an adhesion of 0.05 N/19 mm width or more, more preferably 0.10 N/19 mm width or more, and preferably 0.15 N/19 mm width or more. On the other hand, it is possible to avoid the adhesive residue and the die seat portion or the like that may occur when the tape is not successfully adhered to the lead frame and the tape is peeled off. From the standpoint of deformation of the object, the pressure-sensitive adhesive tape has a viscosity of preferably 6.0 N/19 mm width or less, more preferably 5.0 N/19 mm width or less, and preferably 4.0 N/19 mm or less. force.

The peel strength is measured by a commercially available measuring device (for example, Autograph AG-X, manufactured by Shimadzu Corporation).

Similarly, in terms of avoiding the adhesive residue on the encapsulating resin when peeling the tape, the pressure-sensitive adhesive tape - at 180° peeling angle to the encapsulating resin (especially the encapsulating resin described later) -10.0 N/19 The adhesion of mm width or less, preferably 8.0 N/19 mm width or less and more preferably 6.0 N/19 mm or less.

The pressure-sensitive adhesive tape of the present invention is peeled off from the lead frame at an optional stage after the resin encapsulation step. Therefore, in terms of avoiding resin leakage, the pressure-sensitive adhesive tape needs to have an adhesive force to the lead frame even after exposure to a high temperature. However, the pressure-sensitive adhesive tape having too strong adhesion tends to cause adhesive residue and is difficult to peel off. Further, in this case, there is a concern that the pressure-sensitive adhesive tape of this type may be peeled off or damaged by the stress of the pressure-sensitive adhesive tape. In terms of such positions, it is quite undesirable to inhibit the adhesion of the encapsulating resin to be stronger than the adhesion. To this end, the pressure-sensitive adhesive tape has a peel angle of 180° to a lead frame (especially a lead frame formed of a metal plate described later) after heating at 200 ° C for 1 hour - preferably 0.1 N / 19 mm width or more. More, more preferably 0.2 N/19 mm width or more and preferably 0.3 N/19 mm width or more of peel strength (adhesion), on the other hand, preferably 6.0 N/19 mm width or less More preferably 5.0 N/19 mm width or less and preferably 4.0 N/19 mm width or less.

In the present specification, "peel strength (adhesion)" is measured in accordance with JIS Z0237:1999.

On the other hand, the pressure-sensitive adhesive tape is first adhered to the lead frame and then peeled off from the lead frame at an optional stage. When the pressure-sensitive adhesive tape has too strong adhesive force, it is difficult to peel off the pressure-sensitive adhesive tape, and if this is the case, peeling and damage of the mold resin may be caused by the stress of peeling the pressure-sensitive adhesive tape. Therefore, it is relatively undesirable to suppress the adhesion of the encapsulating resin to be stronger than the adhesion. For example, it is suitable in the semiconductor device process to have an adhesion of about 0.05 to 6.0 N/19 mm in accordance with JIS Z0237 at 25 ° C. Further, after heating the pressure-sensitive adhesive tape at 200 ° C for 1 hour, the adhesion to the lead frame is preferably about 0.1 to 6.0 N / 19 mm width and more preferably about 0.1 to 4.0 N / 19 mm width.

Preferably, the pressure-sensitive adhesive tape of the present invention further comprises a release sheet. The release sheet is a sheet that is in contact with the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer. The release sheet preferably has a specific value of peel strength depending on the type of pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer and the like. The peel strength can be appropriately adjusted by the angle at which the pressure-sensitive adhesive tape is peeled off. For example, a peel strength that satisfies at least one of the following requirements (a) to (d) is preferred, and a peel strength that meets more requirements is more preferable.

(a) The peel strength at a peel angle of 90° ± 15° is 1.5 N/50 mm width or less, preferably 1.0 N/50 mm width or less, more preferably 0.5 N/50 mm width or less, further It is preferably 0.3 N/50 mm width or less and more preferably 0.2 N/50 mm width or less.

(b) Peel strength at a peel angle of 120 ° ± 15 ° is 1.2 N / 50 mm wide Degree or less, preferably 1.0 N/50 mm or less, more preferably 0.8 N/50 mm width or less, further preferably 0.6 N/50 mm width or less and more preferably 0.3 N/50 mm width Or less.

(c) a peel strength at a peeling angle of 150° ± 15° of 1.0 N/50 mm width or less, preferably 0.8 N/50 mm width or less, more preferably 0.6 N/50 mm width or less, further It is preferably 0.5 N/50 mm width or less, more preferably 0.3 N/50 mm width or less, and particularly preferably 0.2 N/50 mm width or less.

(d) The peel strength at the peeling angle of 180°+0° and 180°-15° is 1.0 N/50 mm width or less, preferably 0.8 N/50 mm width or less, more preferably 0.6 N/50 mm The width or less, further preferably 0.5 N/50 mm width or less, still more preferably 0.3 N/50 mm width or less and particularly preferably 0.2 N/50 mm width or less.

When the peeling strength falls within the above range, even in the case of using a tape laminating apparatus or the like which is usually used, unnecessary peeling strength for peeling off the release sheet is not required, and pressure-sensitive tape wrinkles do not occur. Deviation from the adhesion position prevents residual stress from being applied to the pressure-sensitive adhesive tape. Therefore, occurrence of warpage of the lead frame, leakage of the encapsulating resin resin, and the like can be suppressed.

The release sheet comprises a release substrate forming a single layer structure or a multilayer structure and using materials conventional in the art, for example, polymers such as polyvinyl chloride, polyvinylidene chloride, polyester (e.g., polyterephthalic acid). Ethylene glycol), polyimidazole, polyether ether ketone, polyolefin (such as low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, any copolymerized polypropylene, Block copolymerized polypropylene, homopolypropylene, polybutene And polymethylpentene), polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate (optional or alternating a copolymer), an ethylene-butene copolymer, an ethylene-hexene copolymer, a fluororesin, a cellulose resin, and the like.

As the release sheet, it is preferred to use the following release sheet in which at least one side in contact with the pressure-sensitive adhesive layer is subjected to release treatment so that the release sheet does not substantially adhere to the pressure-sensitive adhesive layer. The release treatment can be carried out using methods and materials conventional in the art. Examples of the release treatment include a release treatment by a enamel resin and a release treatment by a fluororesin. Specifically, the light peeling grade and the moderate peeling grade of the CERAPEEL series (Toray Advanced Film Co., Ltd.) are exemplified.

Method for preparing resin-encapsulated semiconductor device

The pressure-sensitive adhesive tape of the present invention is a pressure-sensitive adhesive tape which is used for preparation of a semiconductor device, in particular, resin encapsulation. That is, the pressure-sensitive adhesive tape is used to adhere to at least one side of the lead frame when the semiconductor wafer mounted on the front surface of the lead frame is resin-encapsulated, usually on the back side (the opposite side on which the semiconductor wafer is mounted), and thereafter ) and peeled off after encapsulation.

For example, the pressure-sensitive adhesive tape of the present invention is a method for manufacturing a semiconductor device, the method comprising the steps of: attaching a pressure-sensitive adhesive tape to at least one side of a lead frame, usually a back surface, and mounting the semiconductor wafer on the crystal On the surface of the pellet, the side of the semiconductor wafer was encapsulated with a resin, and the pressure-sensitive adhesive tape was peeled off after encapsulation.

A method of producing a resin-encapsulated semiconductor wafer using the pressure-sensitive adhesive tape of the present invention will be described below.

The method of manufacturing a resin-encapsulated semiconductor wafer generally includes the following steps.

Step 1: Adhesive pressure-sensitive adhesive tape (heat-resistant pressure-sensitive adhesive tape) is adhered to one side of a metal lead frame having a terminal portion and a die holder, the surface being provided with a metal lead frame surface on which a die pad is disposed.

Step 2: Bonding the semiconductor wafer die having the electrode pads to the die pad of the metal lead frame.

Step 3: electrically connecting the tip end of the terminal portion of the metal lead frame and the electrode holder on the semiconductor wafer with a bonding wire.

Step 4: Encapsulating the metal lead frame surface on which the semiconductor wafer is disposed with the encapsulating resin.

Steps 2 to 4 are performed in this order, but it is sufficient that step 1 is performed before step 4. That is, step 1 can be performed before or after step 2 (i.e., before step 3) or after step 3.

Preferably, steps 1 to 4 are performed in this order.

As described above, the pressure-sensitive adhesive tape of the present invention adhered to the lead frame in step 1 is peeled off from the lead frame at an optional stage after the step 4.

Specifically, as shown in FIG. 1A, the pressure-sensitive adhesive tape 20 of the present invention is adhered to one side of the lead frame 11, that is, the back surface.

The lead frame 11 is generally formed of a metal plate such as a Cu-based material (for example, Cu-Fe-P) or an Fe-based material (for example, Fe-Ni). In particular, it is preferred that the electrical contact portion (the connection portion to the semiconductor wafer, which will be described later) is covered (plated) with a lead frame of silver, nickel, palladium, gold or the like. The lead frame 11 generally has a thickness of about 100 to 300 μm.

The lead frame 11 is preferably a lead frame in which a plurality of given configuration patterns (for example, individual QFN configuration patterns) are arranged so as to be easily divided in subsequent cutting steps. Specifically, as shown in Figs. 2A and 2B, the configuration in which the package pattern regions 10 are arranged in a matrix shape on the lead frame 11 is called QFN, MAP-QFN or the like, and is one of the optimum configurations.

The lead frame 11 generally has a die pad 11c and a lead terminal 11b. The die pad 11c is detachably provided from the lead terminal 11b. However, as shown in FIG. 2B, a plurality of lead terminals 11b defined by a plurality of adjacent openings 11a, a die pad 11c arranged in the center of the opening 11a, and optionally four corners of the opening 11a are integrally provided. The lead frame 11 of the die bar 11d of the paddle 11c is preferable. The die pad 11c and the lead terminal 11b may be formed for other functions such as heat release.

The adhesion of the pressure-sensitive adhesive tape 20 to the lead frame 11 is preferably performed to at least the package pattern area 10 of the lead frame 11 and the area other than the lead frame package pattern area 10, that is, the entire resin encapsulation area to be encapsulated by the resin. The area of the outer edge, or the encapsulation pattern area 10, and the area including the entire outer edge of the encapsulation pattern area.

In the case where the pressure-sensitive adhesive tape of the present invention is adhered to the region including the entire outer edge of the resin encapsulation region, the pressure-sensitive adhesive tape may not only adhere to the back surface of the lead frame but also the front surface thereof. In the case where the pressure-sensitive adhesive tape is adhered to the region of the package pattern region 10 and the entire outer edge including the resin encapsulation region to be encapsulated by the resin, the pressure-sensitive adhesive tape preferably adheres only to the back surface of the lead frame.

The lead frame 11 generally has a guide pin hole adjacent to its side (for example, 13 of Fig. 2A) for positioning during resin encapsulation. Therefore, the pressure-sensitive adhesive tape is preferably adhered to a region that does not block the hole. Multiple packages The pattern areas 10 are arranged in the longitudinal direction of the lead frame 11. Therefore, the pressure-sensitive adhesive tape 20 is preferably continuously adhered to cover the plurality of regions.

The semiconductor wafer 15 is mounted on the surface of the lead frame 11 (the side of the pressure-sensitive adhesive tape 20 is not adhered) as shown in Fig. 1B.

Generally, the lead frame 11 is provided with a fixing area for fixing the semiconductor wafer 15, referred to as a die pad 11c, as described above. Therefore, the semiconductor wafer is mounted on the die pad 11c.

Various methods of using, for example, a conductive paste 19, an adhesive tape, or a pressure-sensitive adhesive (for example, a thermosetting pressure-sensitive adhesive) are used to mount the semiconductor wafer 15 on the die pad 11c. In the case of using a conductive paste, a pressure sensitive adhesive or the like, heat curing is usually carried out at a temperature of about 150 to 200 ° C for about 30 to 90 minutes.

The electrode pads (not shown) on the surface of the semiconductor wafer 15 and the lead frame 11 are optionally wire bonded as shown in Fig. 1C.

Wire bonding is performed by bonding leads 16, for example, gold wires or aluminum wires. The wire bonding is usually carried out by a combination of the vibration energy of the ultrasonic waves and the pressure of the pressure applied at 150 to 250 ° C.

Next, the lead frame 11 is sandwiched between the upper and lower molds (not shown), and the encapsulating resin 17 is injected to enclose the semiconductor wafer. In the case where the pressure-sensitive adhesive tape is adhered to the region of the lead frame at the front and the back of the lead frame including the entire outer edge of the resin encapsulation region, the encapsulation may be one side encapsulation and two side encapsulation in this case. In the case where the pressure-sensitive adhesive tape is adhered to the package pattern region 10 and the region including the entire outer edge of the package pattern region 10, one side is preferably encapsulated. In short, in the case of performing one side encapsulation, it is preferred to use the pressure sensitive of the present invention. Adhesive tape.

The semiconductor wafer encapsulation is performed to protect the semiconductor wafer 15 and the bonding leads 16 mounted on the lead frame 11. For example, a method of molding in a mold using a cyclofluororesin or the like is a typical method. In this case, it is preferred to simultaneously enclose a plurality of semiconductor wafers using a mold including a mold having a plurality of cavities and a lower mold. Usually, the heating temperature at the time of resin encapsulation is about 170 to 180 ° C, the curing is carried out at this temperature for several minutes, and then post-molding is carried out for several hours.

Thereafter, the lead frame 11 including the encapsulating resin 17 is taken out from the mold as shown in Fig. 1D.

The pressure-sensitive adhesive tape adhered to the back surface of the lead frame 11 is peeled off as shown in Fig. 1E.

The peeling of the pressure-sensitive adhesive tape 20 after encapsulation is preferably carried out before the above-mentioned mold curing.

Thereafter, the lead frame 11 containing the encapsulating resin 17 is divided into each of the semiconductor wafers 15, whereby the semiconductor device 21 can be obtained as shown in Fig. 1F.

The division of the lead frame per semiconductor wafer 15 can be performed using a rotary cutter or the like of a cutter.

Incidentally, it is sufficient that the pressure-sensitive adhesive tape of the present invention is adhered to one side of the lead frame, preferably the back side, when the semiconductor wafer resin is encapsulated. In the steps shown in Figs. 1A to 1C, the pressure-sensitive adhesive tape can be adhered after mounting the semiconductor wafer, and can be adhered after wire bonding the semiconductor wafer. In summary, the steps are preferably carried out in the order shown in Figures 1A through 1C above. Furthermore, depending on the structure of the semiconductor wafer, wire bonding may not be performed.

Example

The invention is described in more detail with reference to the embodiments and the like, but the invention is not construed as being limited to the embodiments.

Example 1

A 25 μm thick polyimide film (KAPTON 100H (trade name), manufactured by Dupont-Toray Co., Ltd., linear thermal expansion coefficient: 2.7 x 10 ^-5 /K, Tg: 402 ° C) was used as the base material layer. 100 parts by weight of a silicone pressure sensitive adhesive "SD-4586" manufactured by Dow Corning Toray Silicone Co., Ltd. and 2.5 parts by weight of a platinum catalyst were added to toluene and uniformly dispersed in toluene. The resulting dispersion was applied to one side of the base material layer, followed by drying. Thus, a heat-resistant pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer of about 6 μm thick was produced. The pressure-sensitive adhesive had a storage modulus of 4.0 x ^{10 5} Pa at 200 °C. The tape has an adhesion of -180° peel angle to the copper lead frame -1.0 N/19 mm width, and - a copper lead frame after heating at 200 ° C for 1 hour at a 180° peel angle - about 2.7 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -180 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The copper lead frame used has a surface roughness of about 80 nm. The surface roughness was measured by a contact method using the following measuring equipment and measurement conditions.

(measuring equipment)

KLA-Tencor Corporation 'P-15'

(measurement conditions)

Measuring width: 2 mm

Measuring speed: 50 μm/sec

The pressure-sensitive adhesive had a 5% weight loss temperature of 330 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.03 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Example 2

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a 25 μm thick polyimide film (trade name: APICAL 25 NPI (trade name), manufactured by Kaneka Corporation, linear thermal expansion coefficient: 1.7×10 ^-5 K, was used. Tg: 421 ° C) is used as the base material layer. The tape has an adhesion of -180° peel angle to copper lead frame -1.1 N/19 mm width, and - 180° peel angle to copper lead frame after heating at 200 ° C for 1 hour - approx. 2.8 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -3.2 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 330 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.03 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.11%.

Example 3

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a 50 μm thick polyimine film (KAPTON 200H (trade name), manufactured by Dupont-Toray Co., Ltd., linear thermal expansion coefficient: 2.7×10 ^{− was used. 5} / K, Tg: 402 ° C) as a base material layer. The tape has an adhesion of -180° peel angle to copper lead frame -1.3 N/19 mm width, and - 180° peel angle to copper lead frame after heating at 200 ° C for 1 hour - about 3.5 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -3.7 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 330 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.03 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.36%.

Example 4

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer became 15 μm. The tape has an adhesion to a 180° peel angle to a copper lead frame of -1.8 N/19 mm width, and a copper lead frame after heating at 200 ° C for 1 hour at a 180° peel angle - about 4.2 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -4.5 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 330 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.08 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Example 5

A heat-resistant pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that a polymer obtained by copolymerizing 5 parts by weight of an isocyanate crosslinking agent as a crosslinking agent to 100 parts by weight of butyl acrylate and 10 parts by weight of acrylic acid was used. The obtained material was used as a pressure-sensitive adhesive. The tape has a storage modulus of from -200 ° C to 1.0 x ^{10 6} Pa. The tape has an adhesion to a copper lead frame of -0.5 N/19 mm width at a peel angle of 180°, and a copper lead frame after heating at 200 ° C for 1 hour at a 180° peel angle - about 1.5 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -80 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 270 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.5 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Comparative Example 1

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a 25 μm thick polyethylene terephthalate film (TEONX Q81 (trade name), manufactured by Teijin DuPont-Teijin Japan Limited, linear thermal expansion coefficient: 1.0 was used. X10 ^-5 /K, Tg: 156 ° C) is used as the base material layer. The tape has an adhesion of -180° peel angle to copper lead frame -0.9 N/19 mm width, and - 180 ° peel angle to copper lead frame after heating at 200 ° C for 1 hour - about 2.5 N / 19 mm width Adhesion. Further, the tape had an adhesion of -2.8 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 270 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.03 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.42%.

Comparative Example 2

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a 25 μm thick polyphenylene sulfide film (TOREL1NA 3030 (trade name), manufactured by Toray Industries, Inc., linear thermal expansion coefficient: 3.2×10 ^-5 /K) was used. , Tg: 127 ° C) as a base material layer. The tape has an adhesion to a 180° peel angle to a copper lead frame of -0.9 N/19 mm width, and a copper lead frame after heating at 200 ° C for 1 hour at a 180° peel angle - about 2.5 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -2.9 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 270 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.03 mg / g. Further, the heat shrinkage of the base material layer after heating at 180 ° C for 3 hours was 1.9%.

Example 6

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that a 12.5 μm thick polyimine film (KAPTON 50H (trade name), manufactured by Dupont-Toray Co., Ltd., linear thermal expansion coefficient: 2.7×10 ^{− was used. 5} K, Tg: 404 ° C) as a base material layer and the pressure-sensitive adhesive layer thickness was changed to 40 μm or more. The tape has an adhesion of -180° peel angle to copper lead frame -3.8 N/19 mm width, and - 180° peel angle to copper lead frame after heating at 200 ° C for 1 hour - about 5.5 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -6.5 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 330 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.32 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Example 7

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that 2 parts by weight of a platinum catalyst was added using 100 parts by weight of a silicone pressure sensitive adhesive "SD-4560" manufactured by Dow Corning Toray Silicone Co., Ltd. The material is used as a pressure sensitive adhesive. The pressure-sensitive adhesive has a storage modulus of from -200 ° C to 8.0 x 10 ³ Pa. The tape has an adhesion of -180° peel angle to copper lead frame -1.2N/19 mm width, and - 180° peel angle to copper lead frame after heating at 200 ° C for 1 hour - about 3.4 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -18 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature at 320 ° C, and the amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 0.12 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Example 8

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that 100 parts by weight of a silicone pressure sensitive adhesive "SD-4284" manufactured by Dow Corning Toray Silicone Co., Ltd. was used, and 0.6 part by weight of benzoyl peroxide was added. A material obtained by using formazan as a crosslinking agent is used as a pressure-sensitive adhesive. The tape had an adhesion to a width of the copper lead frame of -7.0 N/19 mm at a peel angle of 180°, and the pressure-sensitive adhesive had a storage modulus of from 200 ° C to 6.0 x 10 ⁴ Pa. The tape had an adhesion to the copper lead frame after heating at 200 ° C for 1 hour at a 180° peel angle - about 10.5 N / 19 mm width. Further, the tape had an adhesion of -12.3 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive has a 5% weight loss temperature of 310 ° C, and the pressure is sensitive. The amount of gas produced by heating the adhesive at 200 ° C for 1 hour was 0.21 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Example 9

A heat-resistant pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that 2 parts by weight of an isocyanate crosslinking agent was used as a crosslinking agent, and 3 parts by weight of acrylic acid and 100 parts by weight of 2-ethylhexyl acrylate were copolymerized. The material obtained in the polymer is used as a pressure-sensitive adhesive. The pressure-sensitive adhesive has a storage modulus of from -200 ° C to 7.0 x ^{10 5} Pa and a 5% weight loss temperature of 230 ° C.

The tape has an adhesion of -180° peel angle to copper lead frame -1.2 N/19 mm width, and - 180° peel angle to copper lead frame after heating at 200 ° C for 1 hour - approx. 2.5 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -85 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The amount of gas generated by the pressure-sensitive adhesive after heating at 200 ° C for 1 hour was 0.65 mg / g. Further, the heat shrinkage degree of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Example 10

A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that 2 parts by weight of a platinum catalyst was added using 100 parts by weight of a silicone pressure sensitive adhesive "SD-4585" manufactured by Dow Corning Toray Silicone Co., Ltd. The material is used as a pressure sensitive adhesive. The amount of gas generated after the pressure-sensitive adhesive was heated at 200 ° C for 1 hour was 1.2 mg / g. Further, the pressure-sensitive adhesive has a storage modulus of from -200 ° C to 1.0 x ^{10 5} Pa. The tape has an adhesion of -180° peel angle to copper lead frame -1.3 N/19 mm width, and - 180° peel angle to copper lead frame after heating at 200 ° C for 1 hour - about 2.0 N/19 mm The adhesion of the width. Further, the tape had an adhesion of -80 N/19 mm to the resin-encapsulated resin at a peel angle of 180°.

The pressure-sensitive adhesive had a 5% weight loss temperature of 310 ° C. Further, the heat shrinkage of the base material layer after heating at 180 ° C for 3 hours was 0.35%.

Test Example 1

For the above preparation samples, the wire bonding ability, the shielding property of the resin encapsulation, and the tape peeling ability were verified by the following methods. The results of each test are shown in Table 1 below.

<Evaluation of wire bonding ability>

The tape laminate apparatus "PL 55TRM" (manufactured by Nitto Denko Corporation) was used to adhere the heat-resistant pressure-sensitive adhesive tape to the outer edge side of the copper lead frame in which 4x4 pieces of the silver-plated terminal area were provided with one side of the 16-pin type QFN. . The semiconductor wafer was adhered to the die pad region of the lead frame using an epoxy-phenol type silver paste and fixed to the region by curing at 180 ° C for 1 hour.

The lead frame was fixed to a heat block heated to 200 ° C in the form of vacuum suction from the side of the heat-resistant pressure-sensitive adhesive tape, and then fixed by holding the peripheral portion of the lead frame with a wind clamp. These were wire bonded using a 115 KHz wire bonding machine (UTC-300B1, manufactured by Shinkawa Ltd.) in a 25 μm diameter gold wire (GMG-25, manufactured by Tanaka Holdings Co., Ltd.) under the following conditions.

First joint pressure: 100 g

First engagement application time: 10 milliseconds

Second joint pressure: 150 g

Second engagement application time: 15 milliseconds

The drawing strength of the lead wire prepared by the above method was measured by a pull tester (joining tester PTR-30, manufactured by Rhesca Corporation). The evaluation was "success" when the following two conditions were met, and the number of successful leads/all leads of 100 lead wire bonding of the lead frame in each sample was referred to as "success rate".

(condition)

Condition 1: The fracture caused by the drawing test is not the interface fracture of the first joint (1st joint) and the second joint (2nd joint).

Condition 2: The pull strength shows a value of 4 gf or more.

<Evaluation of masking characteristics>

The heat-resistant pressure-sensitive adhesive tape was adhered to the outer side of the copper lead frame in which 4x4 pieces of the 16-pin type QFN having one side of the silver-plated termination area were arranged.

The lead frame together with the pressure-sensitive adhesive tape was subjected to wire bonding under the above-described wire bonding conditions, and then pre-heated at 175 ° C with an epoxy encapsulating resin (HC-300, manufactured by Nitto Denko Corporation): 40 seconds, injection time: 11.5 Seconds and curing time: 120 seconds were molded using a molding machine (Model-Y-Series, manufactured by TOWA). The heat resistant tape was peeled off, and it was confirmed that the resin leaked. A test was applied to 30 lead frames and the ratio of resin leakage was confirmed.

<Evaluation of Adhesive Residues>

The encapsulating resin surface of the tape peeling surface of the sample for evaluating the masking property, and the lead frame surface were visually observed. In Table 1, when adhesive residue is observed In the case of slag, it is referred to as "+", and when no adhesive residue is observed, it is referred to as "-". Furthermore, when the measurement is not feasible, it is referred to as "ND".

<Rework characteristics>

The heat-resistant pressure-sensitive adhesive tape was adhered to the outer side of the copper lead frame in which 4x4 pieces of the 16-pin type QFN having one side of the silver-plated termination region were arranged, and peeled off at a peel angle of 180°. Confirm the shape of the lead frame after peeling off the tape. In Table 1, when the shape of the lead frame is not observed to be deformed, it is referred to as "possible".

The characteristics and evaluation results of the tapes are shown in Table 1 below. The samples of Examples 1 to 5 satisfy all the characteristics. However, in Comparative Examples 1 and 2, since the base material layer was shrunk during wire bonding, sufficient wire bonding ability and shielding characteristics were not obtained.

In Example 6, the thickness of the pressure-sensitive adhesive layer was too thick and in Example 7, the elastic modulus of the pressure-sensitive adhesive was too low. Therefore, although the problem of the encapsulation resin shielding property has not been confirmed, sufficient wire bonding ability is not obtained.

In Example 8, the adhesion to the lead frame was too strong. Therefore, when the tape was peeled off, the lead frame was confirmed to be deformed. In addition, since the adhesion to the lead frame after heating and the adhesion to the encapsulating resin are too strong, when the tape is peeled off, it is confirmed that there is an adhesive residue on the lead frame and the encapsulating resin.

In Example 9, the decomposition temperature of the pressure-sensitive adhesive was too low. Therefore, when the tape was peeled off after the resin was encapsulated, it was confirmed that there was an adhesive residue on the lead frame and the encapsulating resin.

In Example 10, the amount of outgassing was too large. Therefore, wire bonding is impossible.

The results obtained above are shown in Table 1 below.

From the above results, there is obtained a heat-resistant pressure-sensitive adhesive tape which can be suitably prevented from leaking in the encapsulation step and which is difficult to cause trouble in a series of steps of manufacturing a MAP type which simultaneously encloses a large number of packages.

Example 11

A 25 μm thick polyimide film (KAPTON 100H (trade name), manufactured by Dupont-Toray Co., Ltd., measured by DMA method: 402 ° C) was used as a base material layer. 100 parts by weight of a silicone pressure sensitive adhesive "SD-4586" manufactured by Dow Corning Toray Silicone Co., Ltd. and 2.5 parts by weight of a platinum catalyst were added to toluene and uniformly dispersed in toluene. The resulting dispersion was applied to a layer of a substrate material, followed by drying. Thus, a heat-resistant pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer of about 10 μm thick was produced. The pressure-sensitive adhesive was coated with Teflon (registered trademark) and immersed in toluene at room temperature for 1 week. Before and after impregnation The gel fraction is measured as a change in weight. As a result, the gel fraction was 72.1%.

Using a manual roller to adhere the heat-resistant pressure-sensitive adhesive tape to the upper portion at the normal temperature (on the opposite side of the lead frame having the die pad side), 4x4 copper leads having one side of the silver-plated termination region and a 16-pin type QFN are arranged. The outer edge of the frame.

To reproduce the heat treatment in the semiconductor wafer mounting process, the lead frame was cured at 200 ° C for 1 hour.

The lead frame was fixed to a heat block heated to 225 ° C in the form of vacuum suction from the side of the heat-resistant pressure-sensitive adhesive tape, and then fixed by fixing the peripheral portion of the lead frame with a wind clamp. These were wire bonded using a 115 KHz wire bonding machine (UTC-300B1, manufactured by Shinkawa Ltd.) in a gold wire (GMG-25, manufactured by Tanaka Holdings Co., Ltd.) having a diameter of 25 μm under the following conditions.

First joint pressure: 100 g

First engagement application time: 10 milliseconds

Second joint pressure: 150 g

Second engagement application time: 15 milliseconds

These were molded with an epoxy encapsulating resin (HC-300B6, manufactured by Nitto Denko Corporation) at 175 ° C with a preheat setting: 3 seconds, injection time: 12 seconds, and curing time: 90 seconds. Y-series, manufactured by TOWA). The heat-resistant pressure-sensitive adhesive tape was peeled off. Thus, a QFN package was fabricated.

Example 12

100 parts by weight of a butyl acrylate monomer as a constituent monomer and 5 parts by weight of an acrylic monomer were copolymerized to obtain an acrylic copolymer. Will weigh 1.0 A part of an epoxy crosslinking agent (Tetrad-C, manufactured by Mitsubishi Gas Chemical Company, Inc.) and 1.5 parts by weight of an isocyanate crosslinking agent (CORONATE-L, manufactured by Nippon Polyurethane Industry Co., Ltd.) are added to 100 parts by weight of acrylic acid. A copolymer to prepare a pressure-sensitive adhesive composition. The gel fraction of the pressure-sensitive adhesive was measured in the same manner as in Example 11. The gel fraction was 97.8%. Thereafter, a QFN package was prepared in the same manner as in Example 11.

Comparative Example 3

A QFN package was prepared in the same manner as in Example 11 except that a 25 μm thick polyether fluorene film (SUPERIO UT, manufactured by Mitsubishi Resin Co., Ltd., Tg: 239 ° C (according to DMA method)) was used as the base material layer. other than.

Comparative Example 4

A QFN package was prepared in the same manner as in Example 12 except that the same polyether quinone film used in Comparative Example 3 was used as the base material layer.

Example 13

A QFN package was prepared in the same manner as in Example 12 except that the epoxy crosslinking agent was not added to the pressure-sensitive adhesive layer. As a result of measuring the gel fraction of the pressure-sensitive adhesive in the same manner as in Example 11, the gel fraction was 46.2%.

Comparative Example 5

A QFN package was prepared in the same manner as in Example 13 except that the same polyether quinone film used in Comparative Example 3 was used as the base material layer.

Test Example 2

The wire bonding success rate of the QFN package prepared above (shown as "W/B" in Table 2) and the occurrence of adhesive residue when the tape was peeled off after the completion of the process were measured.

The wire bonding success rate is obtained by performing wire bonding on all sides 64 pins of one side of the 16-pin type QFN, and calculating the number of pins that can accurately place the leads. The occurrence of the adhesive residue after peeling off the tape was confirmed by visual observation of the QEN package.

The results obtained are shown in Table 2 below.

In Example 11, the wire bonding success rate was the best, and the tape was peeled off without the adhesive residue.

In Example 12, the wire bonding success rate was the best, and the tape was peeled off without the adhesive residue, similar to Example 11.

In Comparative Examples 3 and 4, the tape was peeled off without the adhesive residue. However, since the glass transition point (Tg) of the base material is close to the temperature at the time of wire bonding, the wire bonding success rate is lowered as compared with Examples 11 and 12.

In Example 13 and Comparative Example 5, since the pressure-sensitive adhesive had a small gel fraction and low elasticity, wire bonding could not be performed at all. When the tape is peeled off, adhesive residue occurs on the entire surface.

From the above results, it is possible to provide a heat-resistant pressure-sensitive adhesive tape for semiconductor device preparation which suppresses abnormal changes in the properties of the base material due to heat during the use step and which can be peeled off after use without adhesive residue.

Example 14

A 25 μm thick polyimide film (KAPTON 100H (trade name), manufactured by Dupont-Toray Co., Ltd.) was used as the base material layer. 100 parts by weight of a silicone pressure sensitive adhesive (SD-4560, manufactured by Dow Coring Toray Silicone Co., Ltd.) and 2.5 parts by weight of a platinum catalyst were added to toluene and uniformly dissolved therein to prepare a dispersion. The resulting dispersion was applied to one side of the base material layer and dried to prepare a heat-resistant pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer having a thickness of about 15 μm. A PET separator (MRS-50S, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) having a thickness of about 50 μm was adhered to the heat-resistant pressure-sensitive adhesive tape. Thus, a heat-resistant pressure-sensitive adhesive tape was produced. The tape has a separator peeling force (peel strength) of -180° peel angle of -180° N/50 mm, and a separator peeling force of -0.30/50 mm at a peeling angle of 90° (peeling speed: 300 mm/min) ).

Example 15

A 25 μm thick polyimide film (KAPTON 100H (trade name), manufactured by Dupont-Toray Co., Ltd.) was used as the base material layer. 100 parts by weight of a copolymer comprising butyl acrylate and acrylic acid (100 parts by weight and 5 parts by weight) and 0.4 parts by weight of an epoxy crosslinking agent were added to toluene and uniformly dispersed therein to prepare a dispersion. The resulting dispersion was applied to one side of the base material layer and dried to prepare a heat-resistant pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer having a thickness of about 15 μm. tape. A PET separator (#38 CERAPEEL, manufactured by Toray Advanced Film Co., Ltd.) having a thickness of about 38 μm was adhered to the heat-resistant pressure-sensitive adhesive tape. Thus, a heat-resistant pressure-sensitive adhesive tape was produced. The tape had a separator peeling force of -120° peeling angle of -0.10 N/50 mm, and a separator peeling force of -150/50 mm at a peeling angle of 150° (peeling speed: 300 mm/min).

Example 16

A heat-resistant pressure-sensitive adhesive tape was obtained in the same manner as in Example 1, except that a PET separator having a thickness of about 38 μm (#38 CERAPEEL, manufactured by Toray Advanced Film Co., Ltd.) was used as a separator and adhered to the heat resistance. Pressure sensitive adhesive tape. The tape had a separator peeling force at a 180° peel angle of -180 N/50 mm, and a separator peeling force at a 90° peel angle of -2.40/50 mm (peeling speed: 300 mm/min).

Example 17

A heat-resistant pressure-sensitive adhesive tape was obtained in the same manner as in Example 2 except that a PET film (LUMIRROR #38 S-10, manufactured by Toray Polyester Film Co., Ltd.) having a thickness of about 38 μm was used as a separator and adhered thereto. This heat-resistant pressure-sensitive adhesive tape is not included. The tape had a separator peeling force at a peel angle of -3.50 N/50 mm at 120°, and a separator peeling force at a peel angle of 150° - 3.0/50 mm (peeling speed: 300 mm/min).

Test Example 3

Fabrication of Examples 14 to 17 using a lead frame anti-burring molding masking tape laminating device (PL-55TRM, manufactured by Nitto Seiki Co., Ltd.) Each of the heat-resistant pressure-sensitive adhesive tapes is adhered to the outer edge side of the copper lead frame in which the one-side 16-pin type QFN of one unit of 4 units x 4 units is arranged.

After that, do the following:

(a) Bonding the semiconductor wafer and curing (180 ° C, 1 hour)

(b) Wire bonding

(c) Molding (175 ° C, preheating: 40 seconds, injection time: 11.5 seconds, curing time: 120 seconds)

(d) Stripping heat-resistant pressure-sensitive adhesive tape

(e) Post-mold curing (175 ° C, 3 hours)

(f) Segmentation (individual division) by a cutter to obtain individual QFN type semiconductor devices.

The resin leakage observation results of the QFN thus obtained are shown in Table 3 below.

In the heat-resistant pressure-sensitive adhesive tapes of Examples 14 and 15, the tape position deviation and the wrinkles after the adhesive tape were not generated, and no resin leakage occurred at the time of molding.

On the other hand, the heat-resistant pressure-sensitive adhesive tapes of Examples 16 and 17 In this case, the position of the tape is deviated and due to the heavy separator peeling force, wrinkles are generated when the separator is peeled off. Furthermore, the lead frame warps due to residual stress of the tape. As a result, the lead frame is not properly held at the time of molding, and most of the resin leakage occurs.

The pressure-sensitive adhesive tape of the present invention suitably avoids resin leakage in the encapsulation step, and is difficult to cause trouble even in a series of steps of the MAP-QFN application, and has excellent peeling ability after resin encapsulation. Therefore, the tape can be widely used in a method of manufacturing a semiconductor device.

Although the present invention has been described in detail and reference to the specific embodiments thereof, it is obvious to those skilled in the art that various changes and modifications can be made without departing from the scope.

The present application is based on Japanese Patent Application No. 2010-201905, the entire disclosure of which is incorporated herein by reference.

10‧‧‧Package area

11‧‧‧ lead frame

11a‧‧‧ Opening

11b‧‧‧ lead terminal

11c‧‧‧ die holder

11d‧‧‧die rod

13‧‧‧ Guide pin hole

15‧‧‧Semiconductor wafer

16‧‧‧bonding leads

17‧‧‧Encapsulation resin

19‧‧‧Conductive adhesive

20‧‧‧ Pressure-sensitive adhesive tape

21‧‧‧Semiconductor device

1A to 1F are flowcharts showing a process of an example of a method of fabricating a semiconductor device according to the present invention.

2A is a plan view showing an example of a lead frame used in a method of fabricating a semiconductor device according to the present invention, and FIG. 2B is an enlarged view of a main portion of the lead frame.

10‧‧‧Package area

11‧‧‧ lead frame

11a‧‧‧ Opening

11b‧‧‧ lead terminal

11c‧‧‧ die holder

20‧‧‧ Pressure-sensitive adhesive tape

Claims (17)

A pressure-sensitive adhesive tape for resin encapsulation in manufacturing a resin-encapsulated semiconductor device, the pressure-sensitive adhesive tape comprising: a base material layer which does not have a glass in a temperature region of 260 ° C or lower a transformation temperature, and a pressure-sensitive adhesive layer laminated on the base material layer, wherein the pressure-sensitive adhesive layer comprises a silicone pressure-sensitive adhesive, wherein the temperature rise rate is 10 ° C / min, and the atmosphere The thermogravimetric analysis under the measurement conditions in which the gas was air and the gas flow rate was 200 ml/min, and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer had a 5% weight loss temperature of 310 ° C or higher. The pressure-sensitive adhesive tape of claim 1, wherein the base material layer does not have a glass transition temperature in a temperature range of 300 ° C or lower. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the base material layer has a thickness of 5 to 100 μm. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the base material layer has a heat shrinkage of 0.40% or less when heated at 180 ° C for 3 hours. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the pressure-sensitive adhesive layer is laminated on only one side of the base material layer. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the pressure-sensitive adhesive layer has a thickness of from 2 μm to 50 μm. For example, the pressure-sensitive adhesive tape of claim 1 or 2, wherein the pressure is applied The ratio of the thickness (B) of the adhesive layer (B) to the thickness (A) of the base material layer is 3 or less. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive tape is heated at 200 ° C for 1 hour to produce an amount of gas of 1.0 mg / g or less. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the tape has an adhesive force of 0.05 to 6.0 N/19 mm width to the lead frame at a peel angle of 180°. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the tape has a width of 0.1 to 6.0 N/19 mm on the lead frame when heated at 200 ° C for 1 hour and then cooled to a normal temperature and at a peel angle of 180 °. Adhesion. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the tape has an adhesion of 10.0 N/19 mm width or less to the encapsulating resin at a peel angle of 180°. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the pressure-sensitive adhesive layer has a storage modulus of 0.50 × 10 ⁵ Pa or more at 200 °C. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is a silicone pressure sensitive adhesive, an acrylic pressure sensitive adhesive or a rubber pressure sensitive property. Adhesive. The pressure-sensitive adhesive tape of claim 1 or 2, wherein the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer has a gel fraction of 60% or more. Such as the pressure-sensitive adhesive tape of claim 1 or 2, the tape advances One step comprises a release sheet in contact with the pressure-sensitive adhesive layer, the release sheet meeting at least one of the following requirements (a) to (d): (a) a peel strength of 1.5 N at a peel angle of 90° ± 15° /50mm width or less, (b) peel strength of peeling angle of 120 ° ± 15 ° is 1.2N / 50mm width or less, (c) peeling strength of peeling angle of 150 ° ± 15 ° is 1.0N / 50mm The width or less, and (d) the peeling strength of the peeling angle of 180°+0° and 180°-15° is 1.0 N/50 mm width or less. A pressure-sensitive adhesive tape according to claim 1 or 2, wherein the tape is a method for manufacturing a resin-encapsulated semiconductor device, the method comprising: adhering a pressure-sensitive adhesive tape to a terminal portion and a die holder One side of a metal lead frame of the die pad, the surface is opposite to the metal lead frame surface on which the die pad is disposed; the die of the semiconductor wafer having the electrode pad is bonded to the die pad of the metal lead frame Upper; a tip end of the metal lead frame terminal portion and the electrode holder on the semiconductor wafer are electrically connected by a bonding wire; and a metal lead frame surface on which the semiconductor wafer is disposed is covered with the encapsulating resin. A method for producing a resin-encapsulated semiconductor device, the method comprising: applying pressure-sensitive adhesive according to any one of claims 1 to 15 Adhesive tape is adhered to one side of the metal lead frame having the terminal portion and the die pad, the surface being opposite to the metal lead frame surface on which the die pad is disposed; and the semiconductor wafer die having the electrode pad is bonded to the metal lead frame The die pad is electrically connected to the tip end of the metal lead frame terminal portion and the electrode holder on the semiconductor wafer; and the metal lead frame surface on which the semiconductor wafer is disposed is encapsulated by the encapsulating resin.