JP6259665B2 - Film adhesive and dicing tape with film adhesive - Google Patents

Description

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

In the manufacture of semiconductor devices, a method of bonding a semiconductor element to a metal lead frame or the like (so-called die bonding method) has been changed from a conventional gold-silicon eutectic method to a solder or resin paste method. At present, a method using a conductive resin paste is used.

However, the method using a resin paste has a problem that the conductivity is reduced by voids, the thickness of the resin paste is non-uniform, and the pad is contaminated by the protrusion of the resin paste. In order to solve these problems, a film-like adhesive containing a polyimide resin may be used instead of the resin paste (see, for example, Patent Document 1).

On the other hand, power semiconductor devices are expected to grow in the recent semiconductor device market. In a power semiconductor device, high electrical conductivity is required for an element bonding material.

Japanese Patent Laid-Open No. 6-145539

A metal layer may be formed on the back surface of the wafer for a power semiconductor device by metal vapor deposition. As a material for metal vapor deposition, silver and gold are generally used.

However, due to the difference in surface chemical energy between the silicon wafer and the metal layer, the film adhesive is difficult to adhere to the metal layer. If the semiconductor device is assembled in a state in which the film adhesive is not sufficiently in close contact with the metal layer, a problem of chip skipping occurs during dicing.

An object of the present invention is to solve the above-mentioned problems, and to provide a film adhesive and a dicing tape with a film adhesive that have high adhesion to a metal layer and can prevent chip jumping.

The present invention relates to a test wafer comprising a wafer, a titanium film disposed on the wafer, a nickel film disposed on the titanium film, and a silver film disposed on the nickel film. / S and then held at 70 ° C. for 30 minutes, and thereafter the adhesion with the test wafer is 0 when the peeling test is performed at a peeling speed of 100 mm / min, a peeling angle of 180 degrees, and a peeling temperature of 25 ° C. The present invention relates to a film adhesive having a thickness of 2 N / 10 mm or more.

Since the adhesive force with the test wafer is set to a high value of 0.2 N / 10 mm or more, the film adhesive of the present invention has a high adhesive force with the metal layer. Therefore, it is possible to prevent chip skipping during dicing.

The film adhesive of the present invention preferably contains a compound containing a carboxyl group. Thereby, the adhesive force with a metal layer can be improved.

The compound containing a carboxyl group is preferably a polymer containing a carboxyl group. Examples of the polymer containing a carboxyl group include a high molecular weight polymer having a weight average molecular weight of 100,000 or more and a low molecular weight polymer having a weight average molecular weight of 50,000 or less. By using a high molecular weight polymer and a low molecular weight polymer in combination, excellent adhesion can be obtained.

The film adhesive of the present invention is preferably obtained by a solvent coating method. This is because the thickness uniformity is excellent.

The thickness of the film adhesive of the present invention is preferably 5 μm to 100 μm. Thereby, the adhesion area with the metal layer is stabilized. Moreover, the protrusion of the film adhesive can be suppressed.

The film adhesive of the present invention preferably contains a curable resin. Thereby, thermal stability can be improved.

The film adhesive of the present invention preferably contains conductive particles. The content of the conductive particles in the film adhesive of the present invention is preferably 30% by weight to 95% by weight. If it is less than 30% by weight, it tends to be difficult to form a conductive path. On the other hand, when it exceeds 95% by weight, it tends to be difficult to form a film. Moreover, there exists a tendency for the adhesive force with respect to a metal layer to fall.

The conductive particles preferably include plate-like particles having an aspect ratio of 5 or more, and the content of the plate-like particles in 100% by weight of the conductive particles is preferably 5% by weight to 100% by weight.

When only spherical particles are blended, a conductive path is formed by point contact between the spherical particles. On the other hand, in the film-like adhesive containing plate-like particles, a conductive path is formed when the plate-like particles are in surface contact with each other. Therefore, superior conductivity can be obtained as compared with an adhesive containing only spherical particles.

The conductive particles preferably include spherical spherical particles. In the particle size distribution of the spherical particles, there are two or more peaks, the peak A exists in the particle size range of 0.2 μm to 0.8 μm, the peak B exists in the particle size range of 3 μm to 15 μm, and the peak B The ratio of the particle diameter to the particle diameter of peak A is preferably 5-15.

In the film adhesive in which the peak A and the peak B exist in the particle size distribution, the spherical particles forming the peak A are filled between the spherical particles forming the peak B (gap). Are formed in large numbers. Therefore, excellent conductivity can be obtained.

The film adhesive is preferably used as a die attach film.

The present invention also relates to a dicing tape with a film adhesive comprising a dicing tape and a film adhesive disposed on the dicing tape.

It is preferable that the peeling force when the film adhesive is peeled off from the dicing tape under the conditions of a peeling temperature of 25 ° C. and a peeling speed of 300 mm / min is 0.01 N / 20 mm to 3.00 N / 20 mm. As a result, chip skipping can be prevented and pickup can be performed well.

ADVANTAGE OF THE INVENTION According to this invention, the dicing tape with a film adhesive which can prevent chip | tip jump, and a film adhesive can be provided.

It is a schematic sectional drawing of a film adhesive. It is a schematic sectional drawing of the wafer for a test. 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 a schematic sectional drawing of a laminated structure. It is an expansion schematic sectional drawing of a back surface metal wafer. It is sectional drawing which shows the outline of a mode that the back surface metal wafer was separated into pieces. It is a schematic sectional drawing of a semiconductor device.

The present invention will be described in detail below with reference to embodiments, but the present invention is not limited only to these embodiments.

[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 an adhesion force with the test wafer 9 of 0.2 N / 10 mm or more.

As shown in FIG. 2, the test wafer 9 includes a wafer 91, a titanium film 92a disposed on the wafer 91, a nickel film 92b disposed on the titanium film 92a, and a silver film disposed on the nickel film 92b. 92c.

The adhesion force with the test wafer 9 means a peeling force when the film adhesive 3 is peeled from the test wafer 9. The adhesion with the test wafer 9 can be measured by the following method.

Measurement Method First, the film adhesive 3 is attached to the silver film 92c included in the test wafer 9 under the conditions of 60 ° C., 0.2 MPa, and 10 mm / s. Thereafter, it is kept at 70 ° C. for 30 minutes. Then, the peeling force when peeling the film adhesive 3 from the test wafer 9 at a peeling speed of 100 mm / min, a peeling angle of 180 degrees, and a peeling temperature of 25 ° C. is measured.

Since the adhesive force with the film-like adhesive 3 is set to a high value of 0.2 N / 10 mm or more with the test wafer 9, the adhesive force with the metal layer is high. Therefore, it is possible to prevent chip skipping during dicing. The adhesion force is preferably 0.5 N / 10 mm or more.
The upper limit of the adhesion is not particularly limited. For example, the adhesion is preferably 10 N / 10 mm or less.

The adhesion strength with the test wafer 9 can be increased by, for example, blending a compound containing a carboxyl group into the film adhesive 3. Although the reason why the adhesive force is increased by blending a compound containing a carboxyl group is unclear, an ionic bond is formed between the silver ion derived from the silver film 92c and the anion derived from the compound containing a carboxyl group. It is estimated that the adhesion will increase. The content of the compound containing a carboxyl group in the film adhesive 3 is preferably 0.01% by weight to 20% by weight.

Although it does not specifically limit as a compound containing a carboxyl group, For example, the polymer containing a carboxyl group is preferable. Examples of the polymer containing a carboxyl group include a high molecular weight polymer containing a carboxyl group and a low molecular weight polymer containing a carboxyl group.

The weight average molecular weight of the high molecular weight polymer containing a carboxyl group is preferably 100,000 or more, more preferably 300,000 or more, and still more preferably 500,000 or more. Good adhesiveness is acquired as it is 100,000 or more.
On the other hand, the weight average molecular weight of the high molecular weight polymer containing a carboxyl group is preferably 3 million or less, more preferably 2 million or less. When it is 3 million or less, the solubility in an organic solvent and the workability of the dissolved polymer solution are excellent.
The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

The acid value of the high molecular weight polymer containing a carboxyl group is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, and further preferably 5 mgKOH / g or more. When it is 1 mgKOH / g or more, it is easy to obtain an effect of improving the adhesion.
On the other hand, the acid value of the high molecular weight polymer containing a carboxyl group is preferably 1000 mgKOH / g or less, more preferably 500 mgKOH / g or less, and still more preferably 50 mgKOH / g or less. When it is 1000 mgKOH / g or less, it is possible to prevent the conductive particles from being corroded and to prevent a decrease in conductivity.
In addition, an acid value can be measured by the neutralization titration method prescribed | regulated to JISK0070-1992.

The glass transition temperature of the high molecular weight polymer containing a carboxyl group 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. The glass transition temperature is preferably −10 ° C. or lower, more preferably −11 ° C. or lower. When it exceeds −10 ° C., the elastic modulus increases, and it tends to be difficult to attach the film adhesive 3 to the back metal wafer at a low temperature of about 40 ° C. (low temperature sticking property is lowered).
In this specification, the glass transition temperature of a thermoplastic resin means the theoretical value calculated | required by the Fox formula.
As another method for obtaining the glass transition temperature, there is a method for obtaining the glass transition temperature of the thermoplastic resin from the temperature at the maximum heat absorption peak measured by a differential scanning calorimeter (DSC). Specifically, using a differential scanning calorimeter (“Q-2000” manufactured by TA Instruments Inc.), the sample to be measured is about 50 ° C. higher than the predicted glass transition temperature (predicted temperature) of the sample. After heating at a temperature for 10 minutes, the sample is cooled to a temperature lower by 50 ° C. than the predicted temperature, pre-treated, and then heated at a rate of temperature increase of 5 ° C./min in a nitrogen atmosphere to measure the endothermic start point temperature, This is the glass transition temperature.

As the high molecular weight polymer containing a carboxyl group, an acrylic resin is preferable from the viewpoint that there are few ionic impurities, high heat resistance, and reliability of the semiconductor element can be secured.

The acrylic resin is not particularly limited, and includes one or more esters 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. 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 an ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, an isodecyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a stearyl group, an octadecyl group, and a 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 -Hydroxymethylcyclo Hydroxyl group-containing monomers such as (xyl) -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 the like, or a phosphoric acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate may be used.

The content of the high molecular weight polymer containing a carboxyl group in the film adhesive 3 is preferably 1% by weight or more, more preferably 2% by weight or more, and further preferably 5% by weight or more. When it is 1% by weight or more, it is easy to obtain an effect of improving the adhesion.
On the other hand, the content of the high molecular weight polymer containing a carboxyl group is preferably 20% by weight or less, more preferably 15% by weight or less, and still more preferably 10% by weight or less. When it is 20% by weight or less, workability in the die attach step is improved.

The low molecular weight polymer containing a carboxyl group is preferably used in combination with a high molecular weight polymer containing a carboxyl group. Thereby, contact | adhesion power can be raised further.

The weight average molecular weight of the low molecular weight polymer containing a carboxyl group is preferably 500 or more, more preferably 1000 or more. When it is 500 or more, the cohesive strength of the film increases, and the adhesion can be increased.
On the other hand, the weight average molecular weight of the low molecular weight polymer containing a carboxyl group is preferably 50,000 or less, more preferably 30,000 or less. When it is 50,000 or less, the wetness to the adherend is improved and the adhesion can be increased.

The acid value of the low molecular weight polymer containing a carboxyl group is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, and further preferably 50 mgKOH / g or more. When it is 1 mgKOH / g or more, it is easy to obtain an effect of improving the adhesion.
On the other hand, the acid value of the low molecular weight polymer containing a carboxyl group is preferably 1000 mgKOH / g or less, more preferably 500 mgKOH / g or less. When it is 1000 mgKOH / g or less, it is possible to prevent the conductive particles from being corroded and to prevent a decrease in conductivity.

Examples of the low molecular weight polymer containing a carboxyl group include those containing a structural unit derived from a monomer containing a carboxyl group. Examples of the monomer containing a carboxyl group include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid and the like. Of these, acrylic acid is preferable because it is easily introduced into the polymer during polymer synthesis.

The low molecular weight polymer containing a carboxyl group may contain a constituent unit other than the constituent unit derived from a monomer containing a carboxyl group. Examples of other structural units include structural units derived from styrene. By including the structural unit derived from styrene, the dispersibility with other compounding components becomes good.

The content of the low molecular weight polymer containing a carboxyl group in the film adhesive 3 is preferably 0.01% by weight or more, more preferably 0.05% by weight or more. When it is 0.01% by weight or more, it is easy to obtain an effect of improving the adhesion. On the other hand, the content of the low molecular weight polymer containing a carboxyl group is preferably 10% by weight or less, more preferably 1% by weight or less, and still more preferably 0.1% by weight or less. When it is 10% by weight or less, the cohesive strength of the film can be secured, and film formation becomes easy.
In addition, when not using together the low molecular weight polymer containing a carboxyl group, and the high molecular weight polymer containing a carboxyl group, the lower limit of content of the low molecular weight polymer containing a carboxyl group may be 1 weight%, for example.

The film adhesive 3 may contain a thermoplastic resin together with the compound containing a carboxyl group. An example of the thermoplastic resin is an acrylic resin.

The film adhesive 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 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 novolak 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 blending ratio of the epoxy resin and the phenol resin is preferably blended so that the hydroxyl group in the phenol resin is 0.5 to 2.0 equivalents per equivalent of 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. in 100% by weight 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. in 100% by weight 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 back metal wafer at a low temperature of about 40 ° C. (low temperature sticking property is lowered).

The content of the curable resin in the film adhesive 3 is preferably 2% by weight or more, more preferably 5% by weight or more. When it is 2% by weight or more, the curability of the film adhesive 3 is improved. Further, the content of the curable resin is preferably 70% by weight or less, more preferably 60% by weight or less, still more preferably 50% by weight or less, and particularly preferably 45% 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 preferably contains conductive particles. Thereby, electroconductivity can be provided. 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-like adhesive 3, and 0.1 times The above 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. Further, the average particle diameter of the conductive particles is preferably 1 times or less (the thickness of the film adhesive 3 or less), 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.
In addition, the average particle diameter of electroconductive particle is the value calculated | required with the photometric type particle size distribution meter (The product made from HORIBA, apparatus name; LA-910).

The specific gravity of the conductive particles is preferably 0.7 or more, and 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-like particles, spherical particles, needle-like particles, filament-like particles and the like. Especially, it is preferable that electroconductive particle contains a plate-shaped particle and a spherical 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 is an average value obtained by observing the cross section of the film adhesive 3 with a scanning electron microscope (SEM) and measuring the thickness of 100 randomly selected plate-like particles. It is.

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 in 100% by weight of the conductive particles is preferably 5% by weight or more, more preferably 10% by weight or more. The content of the plate-like particles in 100% by weight of the conductive particles may be 100% by weight, but is preferably 50% by weight or less, more preferably 20% by weight or less.

The conductive particles preferably include spherical spherical particles.

It is preferable that at least peak A and peak B exist in the particle size distribution of the spherical particles. For example, it is preferable that the peak A exists in the particle size range of 0.2 μm to 0.8 μm and the peak 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 forming the peak A between the spherical particles forming the peak B. Therefore, excellent conductivity can be obtained.

When the peak A is present in a particle size range of 0.2 μm or more, aggregation of spherical particles is difficult to occur.
The peak A is preferably present in a particle size range of 0.5 μm or more.
When the peak A exists in a particle size range of 0.8 μm or less, the spherical particles forming the peak A are filled between the spherical particles forming the peak B. The peak A is preferably present in a particle size range of 0.75 μm or less.

When the peak B exists in a particle size range of 3 μm or more, the spherical particles forming the peak A are filled between the spherical particles forming the peak B. The peak B is preferably present in a particle size range of 3.5 μm or more.
When the peak B exists in a 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 B is preferably present in a particle size range of 10 μm or less, more preferably in a particle size range of 8 μm or less, and further preferably in a particle size range of 6 μm or less.

The ratio of the peak B particle size to the peak A particle size (peak B particle size / peak A particle size) is preferably 5 or more, more preferably 7 or more. When it is 5 or more, spherical particles forming the peak A are filled between the spherical particles forming the peak B.
On the other hand, the ratio of the particle size of peak B to the particle size of peak 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, peaks other than peak A and peak B may exist.

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 Film adhesive 3 is placed in a crucible and ignited to incinerate film adhesive 3. 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 spherical particles in 100% by weight 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.

Content of the electroconductive particle in the film adhesive 3 becomes like this. Preferably it is 30 weight% or more, More preferably, it is 40 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.

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

The film adhesive 3 can be manufactured by a normal method. For example, an adhesive composition solution containing each of the above components is prepared, and the adhesive composition solution is applied on a base separator so as to have a predetermined thickness to form a coating film, and then the coating film is dried. Thereby, the film adhesive 3 can be manufactured.

Although it does not specifically limit as a solvent used for adhesive composition solution, The organic solvent which can melt | dissolve, knead | mix or disperse | distribute each said component uniformly 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. Of these, a die coater is preferable in terms of high uniformity of coating thickness.

As the base material separator, polyethylene terephthalate (PET), polyethylene, polypropylene, a plastic film or paper whose surface is 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. Moreover, the drying conditions of a coating film are not specifically limited, For example, it can carry out in drying temperature 70-160 degreeC and drying time 1-5 minutes.

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

Although the thickness of the film adhesive 3 is not specifically limited, 5 micrometers or more are preferable and 15 micrometers or more are more preferable. If the thickness is less than 5 μm, a portion that does not adhere to the warped backside metal wafer or semiconductor chip occurs, and the adhesion area may become unstable. 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 adhesive 3 can be preferably used for manufacturing a semiconductor device, and can be particularly preferably used for manufacturing a power semiconductor device. Specifically, it can be used as a die attach film for bonding (die attaching) 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 back surface metal wafer in a state of being attached to the dicing tape with a film adhesive can be handled, so the opportunity for handling the back surface metal wafer alone can be reduced and the handling property is good. Therefore, even a recent thin backside metal wafer can be handled well.

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

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

The base material 11 serves as a strength matrix 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 determined as appropriate, but is generally about 5 to 200 μm.

It does not restrict | limit especially as an adhesive used for formation of the adhesive layer 12, For example, common pressure sensitive adhesives, such as an acrylic adhesive and a rubber 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, isopropyl 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, C1-C30, especially C4-C18 linear or branched alkyl esters of alkyl groups such as octadecyl ester and eicosyl ester) and Meth) acrylic acid cycloalkyl esters (e.g., cyclopentyl ester, etc. One or acrylic polymer using two or more of the monomer component cyclohexyl ester etc.). 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 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 cross-linked, 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 3,000,000.

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. Generally, 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, additives such as various conventionally known tackifiers and anti-aging agents may be used for the pressure-sensitive adhesive, if necessary, in addition to the above components.

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.

By irradiating only the portion 12a corresponding to the workpiece pasting portion of the pressure-sensitive adhesive layer 12 shown in FIG. 3, a difference in adhesive strength with the other portion 12b can be provided. 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.

Moreover, the said part 12a in which adhesive force fell remarkably can be formed by hardening the radiation-curing-type adhesive layer 12 according to the film adhesive 3 shown in FIG. 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. Examples include 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 various oligomers such as urethane, polyether, polyester, polycarbonate, and polybutadiene, 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. Generally, 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 adhesive described above, the radiation curable pressure-sensitive adhesive has a carbon-carbon double bond in the polymer side chain or main chain or at the 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 previously copolymerized 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. Moreover, the functional group may be on either side of the acrylic polymer and the compound as long as the acrylic polymer having the carbon-carbon double bond is generated by a combination of these functional groups. 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. Further, as the acrylic polymer, those obtained by copolymerizing the above-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 or the like is usually in the range of 30 parts by weight, preferably in the range of 0 to 10 parts by weight with respect to 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 compounding quantity of a photoinitiator is about 0.05-20 weight part with respect to 100 weight part of base polymers, such as an acryl-type polymer which comprises an 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.

The radiation curable pressure-sensitive adhesive layer 12 may contain a compound that is colored by radiation irradiation, if 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. Preferably it is 2-30 micrometers, Furthermore, 5-25 micrometers is preferable.

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.

It is preferable that the peeling force when the film-like adhesive 3 is peeled off from the dicing tape 1 is 0.01 to 3.00 N / 20 mm under the conditions of a peeling temperature of 25 ° C. and a peeling speed of 300 mm / min. 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.
The peeling force when the film adhesive 3 is peeled from the dicing tape 1 under the conditions of a peeling temperature of 25 ° C. and a peeling speed of 300 mm / min can be measured by the method described in the examples.

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

As shown in FIG. 5, a laminated structure 21 is formed by pressing a dicing tape 10 with a film adhesive on the back surface metal wafer 4. The laminated structure 21 includes a dicing tape 10 with a film adhesive, and a back metal wafer 4 disposed on the dicing tape 10 with a film adhesive.

The back metal wafer 4 includes a semiconductor wafer 41 and a metal layer 42 disposed on the semiconductor wafer 41. Examples of the semiconductor wafer 41 include a silicon wafer, a silicon carbide wafer, and a compound semiconductor wafer. Examples of compound semiconductor wafers include gallium nitride wafers.

Both sides of the semiconductor wafer 41 are defined by a front surface (front noodle) and a back surface facing the front surface.
The surface is a surface on which elements and wirings are formed. The back surface is a surface on which elements and wirings are not formed. A metal layer 42 is disposed on the back surface of the semiconductor wafer 41.

As shown in FIG. 6, the metal layer 42 includes a first metal film 42a, a second metal film 42b disposed on the first metal film 42a, and a third metal film 42c disposed on the second metal film 42b. including. The first metal film 42 a is disposed on the back surface of the semiconductor wafer 41. An example of the first metal film 42a is a titanium film. Examples of the second metal film 42b include a platinum film and a nickel film. Examples of the third metal film 42c include a gold film and a silver film.

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

The pressing 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 press-bonding at a low temperature, it is possible to prevent the thermal influence on the back surface metal wafer 4 and suppress warping of the back surface metal wafer 4.

Moreover, it is preferable that it is 1 * 10 < ⁵ > Pa-1 * 10 < ⁷ > Pa, and it is more preferable that a pressure is 2 * 10 < ⁵ > Pa-8 * 10 < ⁶ > Pa.

Next, heat is applied to the laminated structure 21. Thereby, the adhesive force of the film adhesive 3 with respect to the 3rd metal film 42c can be improved. The holding temperature is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, still more preferably 60 ° C. or higher, and particularly preferably 65 ° C. or higher. The adhesive force of the film adhesive 3 can be improved as it is 40 degreeC or more. The holding temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, further preferably 80 ° C. or lower, and still more preferably 75 ° C. or lower. When the temperature is 100 ° C. or lower, the adhesion of the film adhesive 3 can be increased while suppressing the thermosetting of the film adhesive 3.

The holding time is preferably 5 minutes or more, more preferably 10 minutes or more, and further preferably 20 minutes or more. When it is 5 minutes or longer, the adhesion of the film adhesive 3 can be increased. The holding time is preferably 120 minutes or less, more preferably 60 minutes or less, and even more preferably 45 minutes or less. When it is 120 minutes or less, the thermosetting of the film adhesive 3 can be suppressed.

Next, as shown in FIG. 7, the back surface metal wafer 4 is diced. That is, the back surface metal 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. Further, since the semiconductor wafer 4 is bonded and fixed by the dicing tape 10 with a film adhesive, chip chipping and chip jumping can be suppressed, and damage to the back surface metal wafer 4 can be suppressed.

The semiconductor chip 5 is picked up in order to peel off the semiconductor chip 5 bonded and fixed to the dicing tape with film adhesive 10. 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. 8, the picked-up semiconductor chip 5 is bonded and fixed to the adherend 6 via the film adhesive 3 (die attach).

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 adhesive 3 is thermally cured by heating, and the semiconductor chip 5 and the adherend 6 are bonded.
The temperature of the heat treatment is preferably 80 ° C. or higher, more preferably 120 ° C. or higher, and further preferably 170 ° C. or higher. The temperature of the heat treatment is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. Adhesion can be satisfactorily performed when the temperature of the heat treatment is within the above range. Moreover, the time of heat processing can be set suitably.

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 step 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 sealed 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 step of preparing the back surface metal wafer 4, the step of bonding the film adhesive 3 and the back surface metal wafer 4, and the state where the film adhesive 3 and the back surface metal wafer 4 are bonded together. Thus, the semiconductor device can be manufactured by a method including the step of applying heat to the film adhesive 3 and the back surface metal wafer 4.

More specifically, the method of Embodiment 1 includes a step of preparing a dicing tape 10 with a film adhesive, a step of preparing a back surface metal wafer 4, a dicing tape 10 with a film adhesive and a back surface metal wafer 4. Are laminated together to form a laminated structure 21 and a process of applying heat to the laminated structure 21.

In the method of the first embodiment, usually, after the step of applying heat to the laminated structure 21, the step of dicing the back surface metal wafer 4 to form the semiconductor chip 5, and picking up the semiconductor chip 5 together with the film adhesive 3. The process further includes a step of die-attaching the semiconductor chip 5 to the adherend 6 via the film adhesive 3.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

The components used in the examples will be described.
Arontack S-2060: Arontack S-2060 manufactured by Toa Gosei Co., Ltd. (acrylic copolymer containing carboxyl group, Mw: 550,000, acid value: 5 mgKOH / g, glass transition temperature: −22 ° C.)
Teisan resin SG-70L: Teisan resin SG-70L manufactured by Nagase ChemteX Corporation (acrylic copolymer containing carboxyl group, Mw: 900,000, acid value: 5 mgKOH / g, glass transition temperature: −13 ° C.)
Teisan resin SG-P3: Teisan resin SG-P3 manufactured by Nagase ChemteX Corporation (acrylic copolymer, Mw: 850,000, glass transition temperature: 12 ° C.)
EOCN-1020-4: EOCN-1020-4 (Epoxy resin solid at 25 ° C.) manufactured by Nippon Kayaku Co., Ltd.
JER828: JER828 manufactured by Mitsubishi Chemical Corporation (epoxy resin which is liquid at 25 ° C)
MEH-7851SS: MEH-7851SS (phenol aralkyl resin) manufactured by Meiwa Kasei Co., Ltd.
1400YM: 1400YM manufactured by Mitsui Mining & Smelting Co., Ltd. (copper powder, spherical, average particle size 4 μm, specific gravity 8.9)
ES-6000: ES-6000 (Silver glass beads, spherical shape, average particle diameter 6 μm, specific gravity 3.9 to 4.0) manufactured by Potters Parrotini Co., Ltd.
AUP-1000: AUP-1000 (gold powder, spherical shape, average particle diameter of 1 μm, specific gravity of 19.3) manufactured by Osaki Kogyo Co., Ltd.
1200YP: 1200YP manufactured by Mitsui Mining & Smelting Co., Ltd. (flaked copper powder, average particle size 3.5 μm, aspect ratio: 10, specific gravity 8.9)
EHD: EHD manufactured by Mitsui Mining & Smelting Co., Ltd. (silver powder, spherical, average particle size 0.7 μm, specific gravity 10.5)
UC-3080: Alfon UC-3080 manufactured by Toa Gosei Co., Ltd. (carboxylic acid-containing acrylic additive (acrylic polymer containing carboxyl group), Mw: 14000, acid value: 230 mgKOH / g)

The test wafer used in the examples will be described.
A backside metal-deposited wafer manufactured by Phenitec Semiconductor was used as a test wafer. The back surface metallized wafer includes a wafer, a titanium film disposed on the wafer, a nickel film disposed on the titanium film, and a silver film disposed on the nickel film. The wafer has a front surface and a back surface. The front surface of the wafer is a mirror-finished surface, and the back surface of the wafer is a surface ground by grinding. The titanium film is disposed on the back surface of the wafer. The total thickness of the back surface metallized wafer is 200 μm.

[Production of film adhesive and dicing tape with film adhesive]
(Examples 1-9 and Comparative Examples 1-2)
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 then dried to produce a film adhesive.

The obtained film adhesive was cut into a circle having a diameter of 230 mm and pasted on a pressure-sensitive adhesive layer of a dicing tape (P2130G manufactured by Nitto Denko Corporation) at 25 ° C. to prepare a dicing tape with a film adhesive. .

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

[Evaluation of adhesion to test wafer]
A polyester adhesive tape (BT-315 manufactured by Nitto Denko Corporation) was bonded to the film adhesive of the dicing tape with a film adhesive for the purpose of holding, and then cut at a width of 10 mm. Subsequently, the laminated body which consists of a film adhesive and a dicing tape was isolate | separated from the polyester adhesive tape.
The wafer for a test was affixed on the film adhesive with which a laminated body is equipped using the 2 kg roller on the conditions of 60 degreeC, 0.2 Mpa, and 10 mm / s. It was then left at 40 ° C. for 2 minutes and then at 70 ° C. for 30 minutes.
Thereafter, using a tensile tester (AGS-J, manufactured by Shimadzu Corporation), the film adhesive is peeled from the test wafer at a peeling angle of 180 degrees, a peeling temperature of 25 ° C., and a peeling speed of 100 mm / min. The peel force was measured.

[Chip skip evaluation]
Using a wafer mounter (MA-3000III manufactured by Nitto Seiki Co., Ltd.) on a film adhesive of a dicing tape with a film adhesive at a bonding speed of 10 mm / min and a bonding temperature of 40 ° C. The wafer was bonded. Thereafter, it was left at 70 ° C. for 30 minutes.
What was obtained by the bonding was diced (divided into pieces) into 0.5 mm × 0.5 mm □ using a dicer (DFD-6361 manufactured by DISCO Corporation). At the time of dicing, it was judged that the piece (chip) flew off and dropped out, and the one that did not fall off was judged as ○.

[Measurement of peel strength between film adhesive and dicing tape]
A polyester pressure-sensitive adhesive tape (BT-315 manufactured by Nitto Denko Corporation) is bonded to the film-like adhesive of the dicing tape with a film-like adhesive, and then cut into a width of 100 mm × 100 mm to prepare a sample. did. About this sample, the film adhesive was peeled from the dicing tape at a peeling speed of 300 mm / min and a peeling temperature of 25 ° C. with a T peel, and the peeling force was measured.

[Comprehensive judgment]
The case where all the following conditions were satisfied was determined as “good”, and the case where any one of the following conditions was not satisfied was determined as “poor”.
Condition (1): Adhesion strength measured by sticking property evaluation with a test wafer is 0.2 N / 10 mm or more.
Condition (2): The determination result of the chip skip evaluation is ◯.
Condition (3): The measurement result of the peel force measurement between the film adhesive and the dicing tape is 0.01 to 3.00 N / 20 mm.

As shown in Table 1, the film adhesive containing any of S-2060, SG-70L, and UC-3080 has higher adhesion to the test wafer than the film adhesive not containing these. No chip jump occurred.

In addition, when it measured also about the adhesive force with respect to the gold film wafer for a test provided with the metal film which contains gold and does not contain silver, the film adhesive containing any of S-2060, SG-70L, and UC-3080 is a test. Adhesion with the metal film wafer was high.

DESCRIPTION OF SYMBOLS 10 Dicing tape 1 with a film adhesive Dicing tape 11 Base material 12 Adhesive layer 3 Film adhesive 4 Back surface metal wafer 41 Semiconductor wafer 42 Metal layer 42a 1st metal film 42b 2nd metal film 42c 3rd metal film 5 Semiconductor Chip 6 Substrate 7 Bonding wire 8 Sealing resin 9 Test wafer 91 Wafer 92a Titanium film 92b Nickel film 92c Silver film

Claims (14)

Including compounds containing carboxyl groups,
A wafer, a titanium film disposed on the wafer, a nickel film disposed on the titanium film,
And a test wafer comprising a silver film disposed on the nickel film, 60 ° C., 0.2 MPa
Pasting under the condition of 10 mm / s, then holding at 70 ° C. for 30 minutes, then peeling rate 1
A film-like adhesive having an adhesive force of 0.2 N / 10 mm or more when the peel test is performed at 00 mm / min, a peel angle of 180 degrees, and a peel temperature of 25 ° C. The film adhesive according to claim 1, wherein the compound is a polymer. The film adhesive according to claim 2, wherein the polymer includes a high molecular weight polymer having a weight average molecular weight of 100,000 or more. The film adhesive according to claim 2 or 3, wherein the polymer contains a low molecular weight polymer having a weight average molecular weight of 50,000 or less. The film adhesive in any one of Claims 1-4 obtained by a solvent coating system. The film adhesive according to any one of claims 1 to 5, having a thickness of 5 µm to 100 µm. The film adhesive in any one of Claims 1-6 containing curable resin. Containing conductive particles,
The conductive particles include plate-like particles having an aspect ratio of 5 or more,
The content of the plate-like particles in 100% by weight of the conductive particles is 5% by weight to 100% by weight.
The film adhesive according to any one of claims 1 to 7. The film adhesive according to claim 8, wherein the content of the conductive particles in the film adhesive is 30 wt% to 95 wt%. Containing conductive particles,
The conductive particles include spherical spherical particles,
In the particle size distribution of the spherical particles, there are two or more peaks,
Peak A exists in the particle size range of 0.2 μm to 0.8 μm, Peak B exists in the particle size range of 3 μm to 15 μm,
The film adhesive according to any one of claims 1 to 7, wherein the ratio of the particle size of the peak B to the particle size of the peak A is 5 to 15. The film adhesive according to claim 10, wherein the content of the conductive particles in the film adhesive is 30 wt% to 95 wt%. The film adhesive in any one of Claims 1-11 used as a die attach film. A dicing tape with a film adhesive, comprising: a dicing tape; and the film adhesive according to any one of claims 1 to 12 disposed on the dicing tape. The peeling force when the film adhesive was peeled off from the dicing tape under the conditions of a peeling temperature of 25 ° C. and a peeling speed of 300 mm / min was 0.01 N / 20 mm to 3.00 N /
The dicing tape with a film-like adhesive according to claim 13, which is 20 mm.

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