WO2015104988A1

WO2015104988A1 - Conductive film-like adhesive and dicing tape with film-like adhesive

Info

Publication number: WO2015104988A1
Application number: PCT/JP2014/083936
Authority: WO
Inventors: 悠樹菅生; 謙司大西
Original assignee: 日東電工株式会社
Priority date: 2014-01-08
Filing date: 2014-12-22
Publication date: 2015-07-16
Also published as: CN105874022A; TW201533215A; KR20160106624A; JP2015129227A

Abstract

Provided are: a conductive film-like adhesive which is capable of suppressing migration and enables the production of a highly reliable semiconductor device; and a dicing tape with a film-like adhesive. The present invention is a conductive film-like adhesive which contains conductive particles and has a time from the start of a migration test based on a deionization water drop method to the occurrence of migration of 500 seconds or more. It is preferable that the film-like adhesive has a chlorine ion concentration of 20 ppm or less.

Description

Conductive film adhesive and dicing tape with film adhesive

The present invention relates to a conductive film adhesive and a dicing tape with a film adhesive.

In the manufacture of semiconductor devices, a method of fixing a semiconductor element to a metal lead frame or the like while maintaining electrical connection (so-called die bonding method) starts with a conventional gold-silicon eutectic, and changes from solder to a conductive resin paste. It has changed.

However, in the method using a conductive resin paste, the thickness of the resin paste may be uneven or the pad may be contaminated by the protrusion of the resin paste. Therefore, a technique using a film-like adhesive having conductivity instead of the resin paste has been proposed (see Patent Document 1).

Japanese Patent Application Laid-Open No. 6-145639

When a conductive film adhesive comes into contact with an electric circuit element such as an electrode pad or pattern wiring formed on an adherend or a semiconductor element, components contained in the adhesive are separated from the adhesive by an electrolysis action due to a potential difference. It has been found that a phenomenon of migration that oozes out over time has occurred, and this is becoming a problem. In recent years, as semiconductor devices have become thinner and smaller, the pitch between electrical circuit elements has become narrower, and in situations where use at high temperatures and high humidity is expected, the semiconductor device has been migrated to reliability. However, there is a possibility that a short circuit may occur between the electric circuit elements and reliability may be greatly impaired.

The present invention has been made in view of the above problems, and provides a conductive film adhesive and a dicing tape with a film adhesive that can suppress migration and can manufacture a highly reliable semiconductor device. With the goal.

That is, the present invention includes conductive particles,
It is a conductive film adhesive having a time of 500 seconds or more from the start of the test in the migration test based on the deionized water dropping method to the occurrence of migration.

In the conductive film adhesive (hereinafter also referred to simply as “film adhesive”), the time from the start of the test to the occurrence of migration in the migration test based on the deionized water dropping method (hereinafter referred to as “migration occurrence time”). )) Is extremely long as 500 seconds or more, so that migration of an adhesive component typified by a component that forms conductive particles can be suppressed, and a semiconductor is provided even when it has a narrowed electric circuit element. The reliability of the device can be improved. If the migration occurrence time is less than 500 seconds, the migration of the adhesive component proceeds rapidly, and the reliability of the semiconductor device may be reduced. The migration test procedure is as described in the examples.

In the film adhesive, the chlorine ion concentration is preferably 20 ppm or less. Thereby, ionization of the electroconductive particle component by chlorine ion can be reduced and migration can be prevented at a higher level.

The film adhesive is preferably formed by a wet coating method. Thereby, the conventional coating process can be used without greatly changing, and the production efficiency can be improved.

The thickness of the film adhesive is preferably 5 μm or more and 100 μm or less. By setting the lower limit of the thickness within the above range, even if the semiconductor element or the like is warped and the distance between the semiconductor element and the adherend varies, a sufficient bonding area can be obtained. Moreover, by making the upper limit of thickness into the said range, the excessive protrusion of a film adhesive can be prevented and contamination of peripheral elements, such as an electrode pad, can be prevented.

The conductive particles include plate-like conductive particles,
The amount of the plate-like conductive particles with respect to the total amount of the conductive particles is preferably 5% by weight or more and 100% by weight or less.

In a conductive film adhesive containing plate-like conductive particles (hereinafter also referred to as “plate-like particles”), a conductive path is formed when the plate-like particles are in surface contact with each other. On the other hand, when only spherical conductive particles (hereinafter also referred to as “spherical particles”) are blended, a conductive path is formed by point contact between the spherical particles. Therefore, the conductive film-like adhesive containing plate-like particles can have superior conductivity compared to the adhesive containing only spherical particles. Moreover, electroconductivity can be provided to a film adhesive efficiently by making content of plate-shaped particle | grain into the said range.

The conductive particles include spherical conductive particles,
In the particle size distribution of the spherical conductive particles, one peak particle size A exists in the particle size range of 0.2 μm to 0.8 μm, and one peak particle size B exists in the particle size range of 3 μm to 15 μm,
The ratio of the peak particle size B to the peak particle size A is preferably 5-15.

In the conductive film adhesive having the peak particle size A and the peak particle size B in the particle size distribution of the conductive particles, the spherical particles having the peak particle size A between the spherical particles having the peak particle size B (gap) As a result, a large number of contact points between spherical particles are formed. Accordingly, excellent conductivity can be obtained.

It is preferable that the content of the conductive particles in the conductive film adhesive is 30% by weight or more and 95% by weight or less. By setting it to 30% by weight or more, it becomes easy to form a conductive path sufficient to impart desired conductivity. On the other hand, when it is 95% by weight or less, it becomes easy to form a film. Moreover, the fall of the adhesive force with respect to the metal layer of a film adhesive can be prevented.

The film adhesive preferably further contains a curable resin. Thereby, the thermal stability of the film adhesive after thermosetting can be improved.

In the present invention, a dicing tape comprising a substrate and an adhesive layer disposed on the substrate,
The dicing tape with a film adhesive provided with the said conductive film adhesive arrange | positioned on the said adhesive layer is also contained.

The peeling force when peeling off the conductive film adhesive and the dicing tape at a peeling speed of 300 mm / min, a peeling temperature of 25 ° C., and a peeling angle of 180 ° is 0.01 N / 20 mm or more and 3.00 N / It is preferable that it is 20 mm or less. By setting the peeling force to 0.01 N / 20 mm or more, chip fly during dicing can be prevented. On the other hand, when the peeling force is 3.00 N / 20 mm or less, good pickup properties can be obtained.

It is a schematic sectional drawing of a film adhesive. It is a schematic sectional drawing of a dicing tape with a film adhesive. It is a schematic sectional drawing of the dicing tape with a film adhesive which concerns on a modification. It is sectional drawing which shows the outline of a mode that the semiconductor wafer has been arrange | positioned on the dicing tape with a film adhesive. It is sectional drawing which shows the outline of a mode that the semiconductor wafer was separated into pieces. It is a schematic sectional drawing of a to-be-adhered body with a semiconductor chip. It is a schematic sectional drawing of a semiconductor device. It is a top view which shows the procedure of a migration test typically.

Hereinafter, the present invention will be described in detail with reference to embodiments, but the present invention is not limited only to these embodiments. However, in some or all of the drawings, parts unnecessary for the description are omitted, and there are parts shown enlarged or reduced for easy explanation.

[Film adhesive]
As shown in FIG. 1, the form of the film adhesive 3 of Embodiment 1 is a film form. The film adhesive 3 has conductivity and thermosetting.

The film adhesive 3 is used for manufacturing a semiconductor device. A method for manufacturing the semiconductor device will be described in detail later.

In the film adhesive 3, the time from the start of the test in the migration test based on the deionized water dropping method to the occurrence of migration is 500 seconds or more. The migration occurrence time is preferably 1000 seconds or more, and more preferably 1500 seconds or more. Since the migration occurrence time is extremely long as in the above range, migration of an adhesive component typified by a component that forms conductive particles can be suppressed. As a result, even if a semiconductor device having a narrowed electric circuit element is used under high temperature and high humidity, reliability can be improved. If the migration occurrence time is less than 500 seconds, the migration of the adhesive component proceeds rapidly, and the reliability of the semiconductor device may be reduced.

In the film adhesive 3, the chlorine ion concentration is preferably 20 ppm or less, more preferably 15 ppm or less, and even more preferably 10 ppm or less. Thereby, the ionization of the adhesive agent component by chlorine ion, especially an electroconductive particle component can be reduced, and a migration can be prevented at a higher level.

The film adhesive 3 preferably contains a thermoplastic resin. Thermoplastic resins include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplasticity. Examples thereof include polyimide resins, polyamide resins such as 6-nylon and 6,6-nylon, phenoxy resins, acrylic resins, saturated polyester resins such as PET and PBT, polyamideimide resins, and fluorine resins. Of these thermoplastic resins, an acrylic resin that has few ionic impurities and high heat resistance and can ensure the reliability of the semiconductor element is particularly preferable.

The acrylic resin is not particularly limited, and one or more of acrylic acid or methacrylic acid ester having a linear or branched alkyl group having 30 or less carbon atoms, particularly 4 to 18 carbon atoms, is used as a component. And a polymer (acrylic copolymer). Examples of the alkyl group include a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, heptyl group, cyclohexyl group, 2- Examples include ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, tetradecyl group, stearyl group, octadecyl group, and dodecyl group.

In addition, the other monomer forming the polymer (acrylic copolymer) is not particularly limited, and for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid Or a carboxyl group-containing monomer such as crotonic acid, an acid anhydride monomer such as maleic anhydride or itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth ) 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate or (4 -Hydroxymethyl cycle Hexyl) -hydroxyl group-containing monomers such as methyl acrylate, styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate Alternatively, a sulfonic acid group-containing monomer such as (meth) acryloyloxynaphthalene sulfonic acid, or a phosphoric acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate can be used.

Among the acrylic resins, those having a weight average molecular weight of 100,000 or more are preferable, those having 300,000 to 3,000,000 are more preferable, and those having 500,000 to 2,000,000 are more preferable. It is because it is excellent in adhesiveness and heat resistance in the said numerical range. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

The glass transition temperature of the thermoplastic resin is preferably −40 ° C. or higher, more preferably −35 ° C. or higher, and further preferably −25 ° C. or higher. When the temperature is lower than −40 ° C., the film-like adhesive 3 becomes sticky and sticks to the dicing tape so that the pick-up property tends to deteriorate. Further, the glass transition temperature of the thermoplastic resin is preferably −5 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −11 ° C. or lower. When the temperature exceeds −10 ° C., the elastic modulus increases, and it tends to be difficult to attach the film adhesive 3 to the semiconductor wafer at a low temperature of about 40 ° C. (low temperature sticking property is lowered). In addition, when the glass transition temperature of the thermoplastic resin is −5 ° C. or lower, the fluidity of the film-like adhesive 3 near the thermosetting temperature can be increased, and voids can be easily eliminated by heating under pressure. It becomes.

In the present specification, the glass transition temperature of the thermoplastic resin refers to a theoretical value obtained by the Fox equation.

The film adhesive 3 preferably contains a curable resin such as a thermosetting resin. Thereby, thermal stability can be improved.

Examples of the curable resin include phenol resin, amino resin, unsaturated polyester resin, epoxy resin, polyurethane resin, silicone resin, and thermosetting polyimide resin. In particular, an epoxy resin containing a small amount of ionic impurities such as chlorine that corrode semiconductor elements is preferable. Moreover, as a hardening | curing agent of an epoxy resin, a phenol resin is preferable.

The epoxy resin is not particularly limited. For example, bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type. Bifunctional epoxy resins such as ortho-cresol novolak type, trishydroxyphenylmethane type, tetraphenylolethane type, etc., and epoxy resins such as hydantoin type, trisglycidyl isocyanurate type, or glycidylamine type are used. Of these epoxy resins, novolac type epoxy resins, biphenyl type epoxy resins, trishydroxyphenylmethane type resins or tetraphenylolethane type epoxy resins are particularly preferred. This is because these epoxy resins are rich in reactivity with a phenol resin as a curing agent and are excellent in heat resistance.

The phenol resin acts as a curing agent for the epoxy resin. For example, a novolac type phenol resin such as a phenol novolak resin, a phenol aralkyl resin, a cresol novolak resin, a tert-butylphenol novolak resin, a nonylphenol novolak resin, or a resol type phenol resin. And polyoxystyrene such as polyparaoxystyrene. Of these phenol resins, phenol novolac resins and phenol aralkyl resins are particularly preferred. This is because the connection reliability of the semiconductor device can be improved.

The mixing ratio of the epoxy resin and the phenol resin is preferably such that, for example, the hydroxyl group in the phenol resin is 0.5 to 2.0 equivalents per equivalent of the epoxy group in the epoxy resin component. More preferred is 0.8 to 1.2 equivalents. That is, if the blending ratio of both is out of the above range, sufficient curing reaction does not proceed and the properties of the cured product are likely to deteriorate.

The film adhesive 3 preferably contains a curable resin that is solid at 25 ° C. and a curable resin that is liquid at 25 ° C. Thereby, favorable low-temperature sticking property is obtained.

In this specification, the liquid state at 25 ° C. means that the viscosity at 25 ° C. is less than 5000 Pa · s. On the other hand, solid at 25 ° C. means that the viscosity at 25 ° C. is 5000 Pa · s or more. The viscosity can be measured using a model number HAAKE Roto VISCO1 manufactured by Thermo Scientific.

In the film adhesive 3, the content of the curable resin solid at 25 ° C. with respect to the total amount of the curable resin is preferably 10% by weight or more, more preferably 12% by weight or more. If it is less than 10% by weight, the film-like adhesive 3 becomes sticky and tends to stick to the dicing tape, resulting in poor pick-up properties. On the other hand, the content of the curable resin solid at 25 ° C. with respect to the total amount of the curable resin is preferably 60% by weight or less, more preferably 30% by weight or less, and further preferably 20% by weight or less. If it exceeds 60% by weight, it tends to be difficult to attach the film adhesive 3 to the semiconductor wafer at a low temperature of about 40 ° C. (low temperature sticking property is lowered).

The total content of the thermoplastic resin and the curable resin in the film adhesive 3 is preferably 5% by weight or more, more preferably 10% by weight or more. When it is 5% by weight or more, it is easy to maintain the shape as a film. Further, the total content of the thermoplastic resin and the curable resin is preferably 70% by weight or less, more preferably 60% by weight or less. When the content is 70% by weight or less, the conductive particles suitably exhibit conductivity.

In the film adhesive 3, the weight of the thermoplastic resin / the weight of the curable resin is preferably 50/50 to 10/90, and more preferably 40/60 to 15/85. When the ratio of the thermoplastic resin increases from 50/50, the thermal stability tends to deteriorate. On the other hand, when the ratio of the thermoplastic resin is less than 10/90, it tends to be difficult to form a film.

The film adhesive 3 contains conductive particles. Thereby, electroconductivity can be provided to the film adhesive 3. Examples of the conductive particles include gold particles, silver particles, copper particles, and coated particles.

The coated particle includes a core particle and a coating film that coats the core particle. The core particles may be either conductive or non-conductive, and for example, glass particles can be used. Examples of the coating film include a film containing gold, a film containing silver, and a film containing copper.

The average particle diameter of the conductive particles is not particularly limited, but is preferably 0.001 times or more (thickness of the film adhesive 3 × 0.001 or more) with respect to the thickness of the film adhesive 3. 1 time or more is more preferable. If it is less than 0.001, it is difficult to form a conductive path and the conductivity tends to be unstable. The average particle size of the conductive particles is preferably 1 times or less (less than the thickness of the film adhesive 3), more preferably 0.8 times or less with respect to the thickness of the film adhesive 3. If it exceeds 1 time, there is a risk of cracking the chip. The average particle diameter of the conductive particles is a value obtained by a photometric particle size distribution meter (manufactured by HORIBA, apparatus name: LA-910).

The specific gravity of the conductive particles is preferably 0.7 or more, more preferably 1 or more. If it is less than 0.7, the conductive particles float when the adhesive composition solution (varnish) is produced, and the dispersion of the conductive particles may be uneven. The specific gravity of the conductive particles is preferably 22 or less, and more preferably 21 or less. If it exceeds 22, the conductive particles are likely to sink, and the dispersion of the conductive particles may be uneven.

The conductive particles may include plate-shaped conductive particles, spherical conductive particles, needle-shaped conductive particles, filament-shaped conductive particles, and the like. Especially, it is preferable that electroconductive particle contains plate-shaped electroconductive particle and spherical electroconductive particle.

Examples of the plate-like particles include plate-like particles having an aspect ratio of 5 or more. When it is 5 or more, the plate-like particles are easily brought into surface contact with each other, and a conductive path is easily formed. The aspect ratio is preferably 8 or more, more preferably 10 or more. On the other hand, the aspect ratio is preferably 10,000 or less, more preferably 100 or less, still more preferably 70 or less, and particularly preferably 50 or less.

The aspect ratio of the plate-like particles is the ratio of the average major axis to the average thickness (average major axis / average thickness). In this specification, the average major axis of the plate-like particles is obtained by observing the cross section of the film-like adhesive 3 with a scanning electron microscope (SEM) and measuring the major axis of 100 randomly selected plate-like particles. Is the average value. The average thickness of the plate-like particles can be obtained by observing the cross section of the film-like adhesive 3 with a scanning electron microscope (SEM) and measuring the thickness of 100 randomly selected plate-like particles. Average value.

The average major axis of the plate-like particles is preferably 0.5 μm or more, more preferably 1.0 μm or more. When the thickness is 0.5 μm or more, the contact probability of the plate-like particles is increased, and conduction is easily obtained. On the other hand, the average major axis of the plate-like particles is preferably 50 μm or less, more preferably 30 μm or less. When the thickness is 50 μm or less, particles are hardly precipitated at the coating varnish stage, and a stable coating varnish can be produced.

The content of plate-like particles with respect to the total amount of conductive particles is preferably 5% by weight or more, more preferably 10% by weight or more. The content of the plate-like particles relative to the total amount of the conductive particles may be 100% by weight, but is preferably 50% by weight or less, more preferably 20% by weight or less. This makes it easy to impart conductivity to the film adhesive.

It is preferable that the conductive particles include spherical conductive particles.

In the particle size distribution of the spherical particles, it is preferable that there are at least two peak particle sizes A and B. For example, it is preferable that one peak particle size A exists in the particle size range of 0.2 μm to 0.8 μm and one peak particle size B exists in the particle size range of 3 μm to 15 μm. In the film adhesive 3, a large number of contact points between the spherical particles are formed by filling the spherical particles having the peak particle size B with the spherical particles having the peak particle size A. Accordingly, excellent conductivity can be obtained.

When the peak particle size A is in the particle size range of 0.2 μm or more, aggregation of spherical particles is difficult to occur. The peak particle size A is more preferably in the particle size range of 0.5 μm or more. On the other hand, when the peak particle size A is in the particle size range of 0.8 μm or less, spherical particles having the peak particle size A are filled between the spherical particles having the peak particle size B. The peak particle size A is more preferably in the particle size range of 0.75 μm or less.

When the peak particle size B is in the particle size range of 3 μm or more, spherical particles having the peak particle size A are filled between the spherical particles having the peak particle size B. The peak particle size B is more preferably in the particle size range of 3.5 μm or more. On the other hand, when the peak particle size B is in the particle size range of 15 μm or less, the surface roughness when the film is formed can be suppressed, and can be stably adhered to the adherend. The peak particle size B is more preferably in the particle size range of 10 μm or less, more preferably in the particle size range of 8 μm or less, and particularly preferably in the particle size range of 6 μm or less.

The ratio of peak particle size B to peak particle size A (peak particle size B / peak particle size A) is preferably 5 or more, more preferably 7 or more. When it is 5 or more, spherical particles having a peak particle size A are filled between spherical particles having a peak particle size B. On the other hand, the ratio of the peak particle size B to the peak particle size A is preferably 15 or less, more preferably 10 or less. When it is 15 or less, spherical particles can be highly filled.

In the particle size distribution of the spherical particles, there may be a peak particle size other than the peak particle size A and the peak particle size B.

The average particle diameter of the spherical particles is preferably 1 μm or more, more preferably 1.5 μm or more. When the thickness is 1 μm or more, good unevenness followability can be obtained. The average particle diameter of the spherical particles is preferably 10 μm or less, more preferably 8 μm or less, and further preferably 5 μm or less. Film moldability is favorable in it being 10 micrometers or less. The particle size distribution and average particle size of the spherical particles can be measured by the following method.

(Measurement of spherical particle size distribution and average particle size)
The film adhesive 3 is put in a crucible and ignited to make the film adhesive 3 ashed. The obtained ash was dispersed in pure water and subjected to ultrasonic treatment for 10 minutes, and the particle size distribution (volume basis) using a laser diffraction / scattering particle size distribution analyzer (“LS 13 320” manufactured by Beckman Coulter, Inc .; wet method). ) And average particle size.

The content of the spherical particles with respect to the total amount of the conductive particles is preferably 5% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 100% by weight. Thereby, the contact point of spherical particles can be increased and electroconductivity can be improved.

The content of the conductive particles in the film adhesive 3 is preferably 30% by weight or more, more preferably 40% by weight or more, still more preferably 60% by weight or more, and particularly preferably 70% by weight or more. If it is less than 30% by weight, it tends to be difficult to form a conductive path. Further, the content of the conductive particles is preferably 95% by weight or less, more preferably 94% by weight or less. If it exceeds 95% by weight, film formation tends to be difficult. Moreover, there exists a tendency for adhesive force to fall.

The film adhesive 3 may appropriately contain a compounding agent generally used in film production, for example, a crosslinking agent, in addition to the above components.

The film adhesive 3 can be produced by a usual method, but a wet coating method is preferable in terms of productivity. For example, an adhesive composition solution containing each of the components described above is prepared, and the adhesive composition solution is applied on a base separator to a predetermined thickness to form a coating film, and then the coating film is dried. Thereby, the film adhesive 3 can be manufactured.

The solvent used in the adhesive composition solution is not particularly limited, but an organic solvent capable of uniformly dissolving, kneading or dispersing the above components is preferable. Examples thereof include ketone solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, acetone, methyl ethyl ketone, and cyclohexanone, toluene, xylene, and the like. The application method is not particularly limited. Examples of the solvent coating method include a die coater, a gravure coater, a roll coater, a reverse coater, a comma coater, a pipe doctor coater, and screen printing. Among these, a die coater is preferable because the uniformity of the coating thickness is high.

As the base material separator, polyethylene terephthalate (PET), polyethylene, polypropylene, a plastic film or paper surface-coated with a release agent such as a fluorine-type release agent or a long-chain alkyl acrylate release agent can be used. Examples of the method for applying the adhesive composition solution include roll coating, screen coating, and gravure coating. The drying conditions for the coating film are not particularly limited, and for example, the drying can be performed at a drying temperature of 70 to 160 ° C. and a drying time of 1 to 5 minutes.

As a method for producing the film adhesive 3, for example, a method of producing the film adhesive 3 by mixing the above components with a mixer and press-molding the obtained mixture is also suitable. A planetary mixer etc. are mentioned as a mixer.

The thickness of the film adhesive 3 is not particularly limited, but is preferably 5 μm or more, and more preferably 15 μm or more. When the thickness is less than 5 μm, a portion where the warped semiconductor wafer or the semiconductor chip does not adhere may occur, and the adhesion area may become unstable. Further, the thickness of the film adhesive 3 is preferably 100 μm or less, and more preferably 50 μm or less. If it exceeds 100 μm, the film adhesive 3 may protrude excessively due to the load of die attachment, and the pad may be contaminated.

The surface roughness (Ra) of the film adhesive 3 is preferably 0.1 to 5000 nm. If it is less than 0.1 nm, it is difficult to blend. On the other hand, if it exceeds 5000 nm, the adherence to the adherend during die attachment may be reduced.

The electrical resistivity of the film adhesive 3 is preferably as low as possible, for example, 9 × 10 ⁻² Ω · m or less. When it is 9 × 10 ⁻² Ω · m or less, the electroconductivity is good and it is possible to cope with small size and high density mounting. On the other hand, the electrical resistivity is preferably 1 × 10 ⁻⁶ Ω · m or more.

The higher the thermal conductivity of the film adhesive 3 is, the more preferable, for example, 0.5 W / m · K or more. When it is 0.5 W / m · K or more, the heat dissipation is good, and it is possible to cope with small and high-density mounting. On the other hand, if it is less than 0.5 W / m · K, heat dissipation is poor, heat is accumulated, and the conductivity may be deteriorated.

The film storage adhesive 3 has a tensile storage elastic modulus at 120 ° C. of preferably 10 MPa or less, more preferably 5 MPa or less. When it is 10 MPa or less, the fluidity of the film adhesive 3 in the vicinity of the thermosetting temperature is high, and it is easy to eliminate voids by heating under pressure. The tensile storage modulus at 120 ° C. is preferably 0.01 MPa or more, more preferably 0.05 MPa or more. When it is 0.01 MPa or more, the film adhesive 3 is difficult to protrude. The tensile storage modulus at 120 ° C. can be measured by the following method.

(Measurement of tensile storage modulus at 120 ° C)
A strip-shaped measurement piece having a length of 30 mm, a width of 10 mm, and a thickness of 400 μm is cut out from the film adhesive 3. Using a fixed viscoelasticity measuring apparatus (RSA-II, manufactured by Rheometric Scientific), the measurement piece was measured for a chuck storage width of 22.6 mm, a tensile storage elastic modulus at 0 ° C. to 200 ° C. with a frequency of 1 Hz, and a temperature increase rate of 10 Measure under conditions of ° C / min.

The tensile storage modulus at 120 ° C. can be controlled by the glass transition temperature of the thermoplastic resin, the blending amount of conductive particles, and the like. For example, by blending a thermoplastic resin having a low glass transition temperature, the tensile storage elastic modulus at 120 ° C. can be lowered.

The film adhesive 3 is used for manufacturing semiconductor devices. Especially, it can be used especially suitably for manufacture of a power semiconductor device. Specifically, it is used as a die attach film that adheres (die attaches) an adherend such as a lead frame and a semiconductor chip. Examples of the adherend include a lead frame, an interposer, and a semiconductor chip. Of these, a lead frame is preferable.

The film adhesive 3 is preferably used in the form of a dicing tape with a film adhesive. When used in this form, the semiconductor wafer in a state of being attached to the dicing tape with a film adhesive can be handled, so that the opportunity to handle the semiconductor wafer alone can be reduced and the handling property is good. Therefore, even a recent thin semiconductor wafer can be handled well.

[Dicing tape with film adhesive]
The dicing tape with a film adhesive will be described.

As shown in FIG. 2, the dicing tape 10 with a film adhesive includes a dicing tape 1 and a film adhesive 3 disposed on the dicing tape 1. The dicing tape 1 includes a base material 11 and an adhesive layer 12 arranged on the base material 11. The film adhesive 3 is disposed on the pressure-sensitive adhesive layer 12.

As shown in FIG. 3, the dicing tape 10 with a film adhesive may have a configuration in which the film adhesive 3 is formed only on a work (semiconductor wafer 4 or the like) affixing portion.

The substrate 11 is a strength base of the dicing tape 10 with a film adhesive, and preferably has ultraviolet transparency. Examples of the base material 11 include low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolyprolene, polybutene, and polymethylpentene. Polyolefin, ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene -Hexene copolymers, polyesters such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyimide, polyetherimide, polyamide, wholly aromatic polyamid , Polyphenyl sulphates id, aramid (paper), glass, glass cloth, fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, metal (foil), and paper.

The surface of the base material 11 is chemically treated by conventional surface treatments such as chromic acid treatment, ozone exposure, flame exposure, high piezoelectric impact exposure, ionizing radiation treatment, etc. in order to improve adhesion and retention with adjacent layers. Alternatively, a physical treatment or a coating treatment with a primer (for example, an adhesive substance described later) can be performed.

The thickness of the substrate 11 is not particularly limited and can be appropriately determined, but is generally about 5 to 200 μm.

The pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer 12 is not particularly limited, and for example, a general pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive can be used. As pressure-sensitive adhesives, acrylic adhesives based on acrylic polymers are used as the base polymer from the standpoint of cleanability of electronic components that are difficult to contaminate such as semiconductor wafers and glass with organic solvents such as ultrapure water and alcohol. preferable.

Examples of the acrylic polymer include (meth) acrylic acid alkyl esters (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, Pentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester, Straight chain or branched chain alkyl esters having 1 to 30 carbon atoms, particularly 4 to 18 carbon atoms, such as octadecyl ester and eicosyl ester) and (Meth) acrylic acid cycloalkyl esters (e.g., cyclopentyl ester, cyclohexyl ester, etc.), etc. One or acrylic polymer using two or more of the monomer component thereof. In addition, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester, and (meth) of the present invention has the same meaning.

The acrylic polymer contains units corresponding to other monomer components copolymerizable with the (meth) acrylic acid alkyl ester or cycloalkyl ester, if necessary, for the purpose of modifying cohesive force, heat resistance and the like. May be. Examples of such monomer components include, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride Acid anhydride monomers such as itaconic anhydride; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate Hydroxyl group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; Sti Contains sulfonic acid groups such as ethylene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid Monomers; Phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate; acrylamide, acrylonitrile and the like. One or more of these copolymerizable monomer components can be used. The amount of these copolymerizable monomers used is preferably 40% by weight or less based on the total monomer components.

Furthermore, since the acrylic polymer is crosslinked, a polyfunctional monomer or the like can be included as a monomer component for copolymerization as necessary. Examples of such polyfunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) An acrylate etc. are mentioned. These polyfunctional monomers can also be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 30% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

The acrylic polymer can be obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. The polymerization can be carried out by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like. From the viewpoint of preventing contamination of a clean adherend, it is preferable that the content of the low molecular weight substance is small. From this point, the number average molecular weight of the acrylic polymer is preferably 300,000 or more, more preferably about 400,000 to 3 million.

In addition, an external cross-linking agent can be appropriately employed for the pressure-sensitive adhesive in order to increase the number average molecular weight of an acrylic polymer as a base polymer. Specific examples of the external crosslinking method include a method of adding a so-called crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound, or a melamine crosslinking agent and reacting them. When using an external cross-linking agent, the amount used is appropriately determined depending on the balance with the base polymer to be cross-linked, and further depending on the intended use as an adhesive. In general, it is preferable to add about 5 parts by weight or less, and further 0.1 to 5 parts by weight with respect to 100 parts by weight of the base polymer. Furthermore, you may use additives, such as conventionally well-known various tackifiers and anti-aging agent, as needed other than the said component for an adhesive.

The pressure-sensitive adhesive layer 12 can be formed of a radiation curable pressure-sensitive adhesive. The radiation curable pressure-sensitive adhesive can easily reduce its adhesive strength by increasing the degree of crosslinking by irradiation with radiation such as ultraviolet rays.

A difference in adhesive strength with respect to the other portions 12b can be provided by irradiating only the portion 12a corresponding to the workpiece pasting portion of the pressure-sensitive adhesive layer 12 shown in FIG. In this case, the portion 12b formed of the uncured radiation curable pressure-sensitive adhesive sticks to the film adhesive 3 and can secure a holding force when dicing.

Further, by curing the radiation-curable pressure-sensitive adhesive layer 12 in accordance with the film adhesive 3 shown in FIG. 3, the portion 12a having a significantly reduced adhesive force can be formed. In this case, the wafer ring can be fixed to the portion 12b formed of an uncured radiation curable adhesive.

That is, when the pressure-sensitive adhesive layer 12 is formed of a radiation curable pressure-sensitive adhesive, the portion 12a is irradiated with radiation so that the pressure-sensitive adhesive force of the portion 12a in the pressure-sensitive adhesive layer 12 <the pressure-sensitive adhesive strength of the other portion 12b. It is preferable.

As the radiation curable pressure-sensitive adhesive, those having a radiation curable functional group such as a carbon-carbon double bond and exhibiting adhesiveness can be used without particular limitation. Examples of the radiation curable pressure-sensitive adhesive include an addition-type radiation curable pressure-sensitive adhesive in which a radiation-curable monomer component or oligomer component is blended with a general pressure-sensitive pressure-sensitive adhesive such as the acrylic pressure-sensitive adhesive or rubber-based pressure-sensitive adhesive. An agent can be illustrated.

Examples of the radiation curable monomer component to be blended include urethane oligomer, urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol. Stall tetra (meth) acrylate, dipentaerystol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, and the like. Examples of the radiation curable oligomer component include urethane, polyether, polyester, polycarbonate, and polybutadiene oligomers, and those having a molecular weight in the range of about 100 to 30000 are suitable. The compounding amount of the radiation-curable monomer component or oligomer component can be appropriately determined in accordance with the type of the pressure-sensitive adhesive layer, and the amount capable of reducing the adhesive strength of the pressure-sensitive adhesive layer. In general, the amount is, for example, about 5 to 500 parts by weight, preferably about 40 to 150 parts by weight with respect to 100 parts by weight of a base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

In addition to the additive-type radiation-curable pressure-sensitive adhesive described above, the radiation-curable pressure-sensitive adhesive has a carbon-carbon double bond in the polymer side chain, main chain, or main chain terminal as a base polymer. Intrinsic radiation curable pressure sensitive adhesives using Intrinsic radiation curable adhesives do not need to contain oligomer components, which are low molecular components, or do not contain many, so the oligomer components do not move through the adhesive over time and are stable. It is preferable because an adhesive layer having a layered structure can be formed.

As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness can be used without particular limitation. As such a base polymer, those having an acrylic polymer as a basic skeleton are preferable. Examples of the basic skeleton of the acrylic polymer include the acrylic polymers exemplified above.

The method for introducing the carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods can be adopted. However, the carbon-carbon double bond can be easily introduced into the polymer side chain for easy molecular design. . For example, after a monomer having a functional group is copolymerized in advance with an acrylic polymer, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is converted into a radiation-curable carbon-carbon double bond. A method of performing condensation or addition reaction while maintaining the above.

Examples of combinations of these functional groups include carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridyl groups, hydroxyl groups and isocyanate groups. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable because of easy tracking of the reaction. In addition, the functional group may be on either side of the acrylic polymer and the compound as long as the combination of these functional groups generates an acrylic polymer having the carbon-carbon double bond. In the preferable combination, it is preferable that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, and the like. As the acrylic polymer, those obtained by copolymerizing the above-mentioned exemplified hydroxy group-containing monomers, ether compounds of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, or the like are used.

As the intrinsic radiation curable pressure-sensitive adhesive, the base polymer (particularly acrylic polymer) having the carbon-carbon double bond can be used alone, but the radiation curable monomer does not deteriorate the characteristics. Components and oligomer components can also be blended. The radiation-curable oligomer component is usually in the range of 30 parts by weight, preferably in the range of 0 to 10 parts by weight, based on 100 parts by weight of the base polymer.

The radiation curable pressure-sensitive adhesive contains a photopolymerization initiator when cured by ultraviolet rays or the like. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropio Α-ketol compounds such as phenone and 1-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- ( Acetophenone compounds such as methylthio) -phenyl] -2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketal compounds such as benzyldimethyl ketal; 2-naphthalenesulfo Aromatic sulfonyl chloride compounds such as luchloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; benzophenone, benzoylbenzoic acid, 3,3′-dimethyl Benzophenone compounds such as -4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2 Thioxanthone compounds such as 1,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketone; acyl phosphinoxide; acyl phosphonate. The blending amount of the photopolymerization initiator is, for example, about 0.05 to 20 parts by weight with respect to 100 parts by weight of the base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

Examples of the radiation curable pressure-sensitive adhesive include photopolymerizable compounds such as an addition polymerizable compound having two or more unsaturated bonds and an alkoxysilane having an epoxy group disclosed in JP-A-60-196956. And rubber-based pressure-sensitive adhesives and acrylic pressure-sensitive adhesives containing photopolymerization initiators such as carbonyl compounds, organic sulfur compounds, peroxides, amines, and onium salt-based compounds.

In the radiation-curable pressure-sensitive adhesive layer 12, a compound that is colored by irradiation with radiation may be contained as necessary. By including a compound to be colored in the pressure-sensitive adhesive layer 12 by irradiation with radiation, only the irradiated portion can be colored. The compound that is colored by irradiation with radiation is a colorless or light color compound before irradiation with radiation, but becomes a color by irradiation with radiation, and examples thereof include leuco dyes. The use ratio of the compound colored by radiation irradiation can be set as appropriate.

The thickness of the pressure-sensitive adhesive layer 12 is not particularly limited, but is preferably about 1 to 50 μm from the viewpoint of preventing chipping of the chip cut surface and compatibility of fixing and holding the film adhesive 3. The thickness is preferably 2 to 30 μm, more preferably 5 to 25 μm.

The film adhesive 3 of the dicing tape 10 with a film adhesive is preferably protected by a separator (not shown). The separator has a function as a protective material for protecting the film adhesive 3 until it is put into practical use. The separator is peeled off when the workpiece is stuck on the film adhesive 3. As the separator, it is also possible to use polyethylene terephthalate (PET), polyethylene, polypropylene, a plastic film or paper whose surface is coated with a release agent such as a fluorine release agent or a long-chain alkyl acrylate release agent.

The dicing tape 10 with a film adhesive can be manufactured by a normal method. For example, the dicing tape 10 with a film adhesive can be manufactured by bonding the adhesive layer 12 of the dicing tape 1 and the film adhesive 3 together.

2. The peeling force (maximum load) when the film-like adhesive 3 is peeled from the dicing tape 1 under the conditions of a peeling temperature of 25 ° C., a peeling speed of 300 mm / min, and a peeling angle of 180 ° is 0.01 N / 20 mm or more. It is preferable that it is 00N / 20mm or less. If it is less than 0.01 N / 20 mm, there is a risk of chip jumping during dicing. On the other hand, if it exceeds 3.00 N / 20 mm, the pickup tends to be difficult.

[Method for Manufacturing Semiconductor Device]
A method for manufacturing a semiconductor device will be described.

As shown in FIG. 4, a dicing tape 10 with a film adhesive is pressure-bonded to the semiconductor wafer 4. Examples of the semiconductor wafer 4 include a silicon wafer, a silicon carbide wafer, and a compound semiconductor wafer. Examples of compound semiconductor wafers include gallium nitride wafers.

Examples of the crimping method include a method of pressing with a pressing means such as a crimping roll.

The pressure bonding temperature (sticking temperature) is preferably 35 ° C. or higher, and more preferably 37 ° C. or higher. The upper limit of the pressure bonding temperature is preferably lower, preferably 50 ° C. or lower, more preferably 45 ° C. or lower. By crimping at a low temperature, it is possible to prevent the thermal effect on the semiconductor wafer 4 and to suppress warping of the semiconductor wafer 4.

The pressure is preferably 1 × 10 ⁵ Pa to 1 × 10 ⁷ Pa, and more preferably 2 × 10 ⁵ Pa to 8 × 10 ⁶ Pa.

Next, as shown in FIG. 5, the semiconductor wafer 4 is diced. That is, the semiconductor wafer 4 is cut into a predetermined size and separated into pieces, and the semiconductor chip 5 is cut out. Dicing is performed according to a conventional method. Further, in this step, for example, a cutting method called full cut in which cutting is performed up to the dicing tape 10 with a film adhesive can be employed. It does not specifically limit as a dicing apparatus used at this process, A conventionally well-known thing can be used. Moreover, since the semiconductor wafer 4 is bonded and fixed by the dicing tape 10 with a film adhesive, chip chipping and chip jump can be suppressed, and damage to the semiconductor wafer 4 can also be suppressed.

The semiconductor chip 5 is picked up in order to peel off the semiconductor chip 5 adhered and fixed to the dicing tape 10 with film adhesive. The pickup method is not particularly limited, and various conventionally known methods can be employed. For example, there is a method in which each semiconductor chip 5 is pushed up by a needle from the dicing tape 10 with film adhesive, and the pushed-up semiconductor chip 5 is picked up by a pickup device.

Here, when the pressure-sensitive adhesive layer 12 is an ultraviolet curable type, the pickup is performed after the pressure-sensitive adhesive layer 12 is irradiated with ultraviolet rays. Thereby, the adhesive force with respect to the film adhesive 3 of the adhesive layer 12 falls, and peeling of the semiconductor chip 5 becomes easy. As a result, the pickup can be performed without damaging the semiconductor chip 5. Conditions such as irradiation intensity and irradiation time at the time of ultraviolet irradiation are not particularly limited, and may be set as necessary.

As shown in FIG. 6, the picked-up semiconductor chip 5 is bonded and fixed to the adherend 6 via the film adhesive 3 to obtain an adherend 61 with a semiconductor chip. The adherend 61 with a semiconductor chip includes an adherend 6, a film adhesive 3 disposed on the adherend 6, and a semiconductor chip 5 disposed on the film adhesive 3.

The die attach temperature is preferably 80 ° C. or higher, more preferably 90 ° C. or higher. The die attach temperature is preferably 150 ° C. or lower, more preferably 130 ° C. or lower. By setting the temperature to 150 ° C. or lower, it is possible to prevent warping after die attachment.

Subsequently, the film-like adhesive 3 is thermally cured by heating the adherend 61 with a semiconductor chip under pressure, and the semiconductor chip 5 and the adherend 6 are fixed. By thermally curing the film adhesive 3 under pressure, voids existing between the film adhesive 3 and the adherend 6 can be eliminated, and the film adhesive 3 is adhered to the adherend 6. The area in contact with can be secured.

Examples of the method of heating under pressure include a method of heating the adherend 61 with a semiconductor chip disposed in a chamber filled with an inert gas.

The pressure of the pressurized atmosphere is preferably 0.5 kg / cm ² (4.9 × 10 ⁻² MPa) or more, more preferably 1 kg / cm ² (9.8 × 10 ⁻² MPa) or more, and further preferably 5 kg. / Cm ² (4.9 × 10 ⁻¹ MPa) or more. If it is 0.5 kg / cm ² or more, voids existing between the film adhesive 3 and the adherend 6 can be easily eliminated. The pressure of the pressurized atmosphere is preferably 20kg ^/ cm 2 (1.96MPa), more preferably 18kg ^/ cm 2 (1.77MPa) or less, more preferably not more than 15kg ^/ cm 2 (1.47MPa). The protrusion of the film adhesive 3 due to excessive pressurization can be suppressed as it is 20 kg / cm ² or less.

The heating temperature at the time of heating under pressure is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, further preferably 120 ° C. or higher, and particularly preferably 170 ° C. or higher. When the temperature is 80 ° C. or higher, the film-like adhesive 3 can have an appropriate hardness, and voids can be effectively eliminated by pressure curing. The heating temperature is preferably 260 ° C. or lower, more preferably 200 ° C. or lower, more preferably 180 ° C. or lower. It can prevent decomposition | disassembly of the film adhesive 3 before hardening as it is 260 degrees C or less.

The heating time is preferably 0.1 hour or longer, more preferably 0.2 hour or longer, and further preferably 0.5 hour or longer. When it is 0.1 hour or longer, the effect of pressurization can be sufficiently obtained. The heating time is preferably 24 hours or less, more preferably 3 hours or less, and even more preferably 1 hour or less.

Next, a wire bonding step of electrically connecting the tip of the terminal portion (inner lead) of the adherend 6 and an electrode pad (not shown) on the semiconductor chip 5 with the bonding wire 7 is performed. As the bonding wire 7, for example, a gold wire, an aluminum wire or a copper wire is used. The temperature during wire bonding is preferably 80 ° C. or higher, more preferably 120 ° C. or higher, and the temperature is preferably 250 ° C. or lower, more preferably 175 ° C. or lower. The heating time is several seconds to several minutes (for example, 1 second to 1 minute). The connection is performed by a combination of vibration energy by ultrasonic waves and pressure energy by pressurization while being heated so as to be within the temperature range.

Subsequently, a sealing process for sealing the semiconductor chip 5 with the sealing resin 8 is performed. This step is performed to protect the semiconductor chip 5 and the bonding wire 7 mounted on the adherend 6. This step is performed by molding a sealing resin with a mold. As the sealing resin 8, for example, an epoxy resin is used. The heating temperature at the time of resin sealing is preferably 165 ° C. or higher, more preferably 170 ° C. or higher, and the heating temperature is preferably 185 ° C. or lower, more preferably 180 ° C. or lower.

If necessary, the sealing material may be further heated (post-curing step). Thereby, the sealing resin 8 which is insufficiently cured in the sealing process can be completely cured. The heating temperature can be set as appropriate.

As described above, in the first embodiment, the film is formed after the step of die-bonding the semiconductor chip 5 on the adherend 6 and the step of die-bonding the semiconductor chip 5 on the adherend 6 via the film adhesive 3. A semiconductor device is manufactured by a method including a step of thermally curing the adhesive 3 under pressure.

More specifically, the method of Embodiment 1 includes the steps of placing the semiconductor wafer 4 on the film adhesive 3 of the dicing tape 10 with film adhesive, and the semiconductor wafer disposed on the film adhesive 3. The semiconductor chip 5 is die-bonded onto the adherend 6 via the step of dicing 4 to form the semiconductor chip 5, the step of picking up the semiconductor chip 5 together with the film adhesive 3, and the film adhesive 3. After the step and the step of die-bonding the semiconductor chip 5 on the adherend 6, a step of thermally curing the film adhesive 3 by heating under pressure is included.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

[Preparation of conductive film adhesive]
(Examples 1 to 3)
According to the mixing ratio shown in Table 1, each component and solvent (methyl ethyl ketone) shown in Table 1 were placed in a stirring vessel of a hybrid mixer (HM-500 manufactured by Keyence), and stirred and mixed in a stirring mode for 3 minutes. The obtained varnish was applied to a release treatment film (MRA50 manufactured by Mitsubishi Resin Co., Ltd.) with a die coater and dried to prepare a conductive film adhesive having a thickness of 30 μm.

In addition, the detail of the component in a table | surface is as follows.
(acrylic resin)
Teisan resin SG-70L: Teisan resin SG-70L manufactured by Nagase ChemteX Corporation (acrylic resin, Mw: 900,000)
(Epoxy resin)
EPICLON EXA-4850-150: EPICLON EXA-4850-150 manufactured by DIC Corporation (epoxy resin having a bisphenol type skeleton, epoxy equivalent 450)
EPICLON HP-4032D: EPICLON HP-4032D manufactured by DIC Corporation (epoxy resin having a naphthalene type skeleton, epoxy equivalents 136 to 148)
EPPN-501HY: EPPN-501HY from Nippon Kayaku Co., Ltd. (an epoxy resin having a polyfunctional skeleton, epoxy equivalents 163 to 175)
(Phenolic resin)
MEH-7851SS: MEH-7851SS (phenol resin, hydroxyl equivalents 201-205) manufactured by Meiwa Kasei Co., Ltd.
MEH-7851-4H: MEH-7851-4H (phenol resin, hydroxyl group equivalents 235 to 245) manufactured by Meiwa Kasei Co., Ltd.
MEH-8000H: MEH-8000H manufactured by Meiwa Kasei Co., Ltd. (phenol resin, hydroxyl group equivalents 139 to 143)
(Thermosetting catalyst)
TPP-K: TPP-K (phosphorus-based catalyst) from Hokuko Chemical Co., Ltd.
(Conductive particles)
1200YP: 1200YP manufactured by Mitsui Mining & Smelting Co., Ltd. (flaked copper powder, average particle size 3.5 μm, specific gravity 8.9)
EHD: EHD manufactured by Mitsui Mining & Smelting Co., Ltd. (silver powder, average particle size 0.7 μm, specific gravity 10.5)

[Evaluation]
The following evaluation was performed about the obtained film adhesive. The results are shown in Table 1.

[Migration test]
The migration test was performed using the migration test apparatus 100 shown in FIG. First, a glass epoxy substrate 101 was prepared. Next, two conductive film adhesives 3 having a width of 1 mm, a length of 50 mm, and a thickness of 30 μm were bonded onto the glass epoxy substrate 101 with an interval of 0.5 mm. Thereafter, the two conductive film adhesives 3 were heated at 140 ° C. for 1 hour, and further heated at 200 ° C. for 2 hours to be thermally cured. Subsequently, a DC power supply circuit including an ammeter was connected between the ends of the conductive film adhesive 3. After 3 μL of deionized water 102 (0.1 μS / cm) was dropped so as to fill the space between the conductive film adhesives 3, the power supply (voltage 2 V) was turned on, and changes in the ammeter were observed. When migration occurs, conduction between the conductive film adhesives 3 is achieved, and the current value of the ammeter rapidly increases. When the test is started when the power is turned on and when migration occurs when the current value suddenly increases, "○" indicates that the elapsed time from the start of the test to the occurrence of migration is 500 seconds or more. The case of less than 500 seconds was evaluated as “x”.

[Chlorine ion content measurement]
The produced conductive film adhesive was heated at 175 ° C. for 1 hour to be thermally cured. The cured film adhesive was sealed in 50 mL of pure water, and chlorine ions were extracted at 121 ° C. for 20 hours. The extract was measured with an ion chromatogram (ICS-3000, manufactured by DIONEX) under the following conditions and analyzed for chlorine content. When the amount of chlorine ions was 20 ppm or less, “◯”, and when the amount exceeded 20 ppm, “×” was evaluated.

(Measurement condition)
Condition: Anion Separation column: Ion Pac AS18 (4 mm x 250 mm)
Guard column: Ion Pac AG18 (4mm x 50mm)
Removal system: ASRS-300 (external mode)
Detector: Electrical conductivity detector Eluent: KOH aqueous solution (using eluent generator EG40)
Eluent flow rate: 1.0 mL / min

The conductive film adhesives of the examples both showed good results in both the migration test and the chlorine ion content measurement, and it was found that a highly reliable semiconductor device could be manufactured with this conductive film adhesive.

DESCRIPTION OF SYMBOLS 10 Dicing tape 1 with a film adhesive Dicing tape 11 Base material 12 Adhesive layer 3 Film adhesive 4 Semiconductor wafer 5 Semiconductor chip 6 Adhering body 61 Adhering body with a semiconductor chip 7 Bonding wire 8 Sealing resin

Claims

Containing conductive particles,
A conductive film adhesive in which the time from the start of the test to the occurrence of migration in the migration test based on the deionized water dropping method is 500 seconds or more.
The conductive film adhesive according to claim 1, wherein the chlorine ion concentration is 20 ppm or less.
The conductive film adhesive according to claim 1 or 2, which is formed by a wet coating method.
The conductive film adhesive film according to any one of claims 1 to 3, wherein the thickness is 5 µm or more and 100 µm or less.
The conductive particles include plate-like conductive particles,
The conductive film adhesive according to any one of claims 1 to 4, wherein the amount of the plate-like conductive particles with respect to the total amount of the conductive particles is 5 wt% or more and 100 wt% or less.
The conductive particles include spherical conductive particles,
In the particle size distribution of the spherical conductive particles, one peak particle size A exists in the particle size range of 0.2 μm to 0.8 μm, and one peak particle size B exists in the particle size range of 3 μm to 15 μm,
The conductive film adhesive according to any one of claims 1 to 4, wherein a ratio of the peak particle size B to the peak particle size A is 5 to 15.
The conductive film adhesive according to any one of claims 1 to 6, wherein the content of the conductive particles in the conductive film adhesive is 30 wt% or more and 95 wt% or less.
The conductive film adhesive according to any one of claims 1 to 7, further comprising a curable resin.
A dicing tape comprising a substrate and a pressure-sensitive adhesive layer disposed on the substrate;
A dicing tape with a film adhesive comprising: the conductive film adhesive according to any one of claims 1 to 8 disposed on the pressure-sensitive adhesive layer.
The peeling force when peeling off the conductive film adhesive and the dicing tape at a peeling speed of 300 mm / min, a peeling temperature of 25 ° C., and a peeling angle of 180 ° is 0.01 N / 20 mm or more and 3.00 N / The dicing tape with a film adhesive according to claim 9, which is 20 mm or less.