JP6555695B2 - Film-like fired material and film-like fired material with support sheet - Google Patents

Description

  The present invention relates to a film-like fired material and a film-like fired material with a support sheet.

In recent years, with the increase in voltage and current of automobiles, air conditioners, personal computers, etc., the demand for power semiconductor elements (power devices) mounted on them has increased. Since power semiconductor elements are used under high voltage and high current, heat generation from the semiconductor elements tends to be a problem.
Conventionally, in order to dissipate heat generated from a semiconductor element, a heat sink may be attached around the semiconductor element. However, if the thermal conductivity at the junction between the heat sink and the semiconductor element is not good, efficient heat dissipation is hindered.

  As a bonding material excellent in thermal conductivity, for example, Patent Document 1 discloses paste-like metal fine particles in which specific heat-sinterable metal particles, a specific polymer dispersant, and a specific volatile dispersion medium are mixed. A composition is disclosed. When the composition is sintered, the solid metal is excellent in thermal conductivity.

JP 2014-111800 A

However, when the fired material is in a paste form as in Patent Document 1, it is difficult to make the thickness of the applied paste uniform, and the thickness stability tends to be poor.
The present invention has been made in view of the actual situation as described above, and an object of the present invention is to provide a film-like fired material that is excellent in thickness stability and thermal conductivity and exhibits excellent shear adhesion after firing. To do. Moreover, it aims at providing the film-like baking material with a support sheet provided with the said film-like baking material.

  Conventionally, it has been considered that the lower the thermal decomposition temperature, the better the materials other than the metal particles contained in the fired material. However, the present inventors have studied the sintering mechanism from the viewpoint of thermophysical properties, and thus have a film-like firing having a specific relationship between a thermogravimetric curve (TG curve) and a differential thermal analysis curve (DTA curve). The present inventors have found that the material is excellent in thickness stability and thermal conductivity, and can exhibit an excellent shear adhesive force after firing, thereby completing the invention.

That is, the present invention includes the following aspects.
[1] A thermogravimetric curve (TG curve), which is a film-like fired material containing sinterable metal particles and a binder component, and is measured from 40 ° C. to 600 ° C. at a temperature rising rate of 10 ° C./min in the air atmosphere. , The time (A) after the start of temperature rise with the largest negative slope,
In a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in an air atmosphere using alumina particles as a reference sample, in the time range from 0 seconds to 2160 seconds after the start of temperature increase. Maximum peak time (B) of
Satisfies the relationship of A <B <A + 200 seconds, and A <2000 seconds.
[2] For a component obtained by removing the sinterable metal particles from the film-like fired material, in a thermogravimetric curve (TG curve) measured from 40 ° C. to 600 ° C. at a temperature rising rate of 10 ° C./min in the air atmosphere, The time (A ′) after the start of temperature rise with the largest negative slope,
About the sinterable metal particles, 960 after starting the temperature increase in a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in the air atmosphere using the alumina particles as a reference sample. Among the peaks observed in the time range of 2 to 2160 seconds, the peak time (B ′) observed in the shortest time,
However, the film-like fired material according to [1], wherein B ′ <A ′ is satisfied.
[3] With respect to the film-like fired material, temperature increase starts in a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in an air atmosphere using alumina particles as a reference sample. The film-like fired material according to [1] or [2], which does not have an endothermic peak in a time range of 0 second to 2160 seconds later.
[4] The film-like fired material according to any one of [1] to [3], wherein the sinterable metal particles are silver nanoparticles.
[5] A film with a support sheet, comprising: the film-like fired material according to any one of [1] to [4]; and a support sheet provided on at least one side of the film-like fired material. Firing material.
[6] The support sheet is a base film provided with a pressure-sensitive adhesive layer.
The film-like fired material with a support sheet according to [5], wherein the film-like fired material is provided on the pressure-sensitive adhesive layer.

  ADVANTAGE OF THE INVENTION According to this invention, the film-form baking material which is excellent in thickness stability and heat conductivity, and exhibits the outstanding shearing adhesive force after baking can be provided. Moreover, the film-form baking material with a support sheet which is provided for the sintering joining of a semiconductor element provided with the said film-form baking material can be provided.

It is sectional drawing which shows typically the film-form baking material based on one Embodiment of this invention. It is sectional drawing which shows typically a mode that it presumes before and after baking of the film-form baking material based on one Embodiment of this invention. It is sectional drawing which shows typically a mode that it presumes before and after baking of other baking materials. It is sectional drawing which shows typically the state by which the film-form baking material with a support sheet based on one Embodiment of this invention was affixed on the ring frame. It is sectional drawing which shows typically the state by which the film-form baking material with a support sheet based on one Embodiment of this invention was affixed on the ring frame. It is a perspective view which shows typically the state by which the film-form baking material with a support sheet based on one Embodiment of this invention was affixed on the ring frame. It is a graph of the TG curve and DTA curve obtained by the measurement. It is a graph of the TG curve and DTA curve obtained by the measurement. It is a graph of the TG curve and DTA curve obtained by the measurement. It is a graph of the TG curve and DTA curve obtained by the measurement.

Embodiments of the present invention will be described below with reference to the drawings as appropriate.
In addition, in order to make the features of the present invention easier to understand, the drawings used in the following description may show the main portions in an enlarged manner for convenience, and the dimensional ratios of the respective components are the same as the actual ones. Not necessarily.

≪Film-like firing material≫
The film-like fired material of the embodiment is a film-like fired material containing sinterable metal particles and a binder component, and heat measured from 40 ° C. to 600 ° C. at a temperature rising rate of 10 ° C./min in an air atmosphere. Measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in an air atmosphere with time (A) after the start of temperature increase having the largest negative slope in the weight curve (TG curve) and alumina particles as a reference sample. In the differential thermal analysis curve (DTA curve), the maximum peak time (B) in the time range from 0 second to 2160 seconds after the start of temperature increase satisfies the relationship of A <B <A + 200 seconds, and A < It is 2000 seconds.
FIG. 1 is a cross-sectional view schematically showing a film-like fired material according to an embodiment. The film-like fired material 1 contains sinterable metal particles 10 and a binder component 20.

The film-like fired material may be composed of one layer (single layer) or may be composed of two or more layers. When the film-like fired material comprises a plurality of layers, these layers may be the same as or different from each other, and the combination of these layers is not particularly limited as long as the effects of the present invention are not impaired.
In the present specification, not only in the case of a film-like fired material, but “a plurality of layers may be the same or different from each other” means “all layers may be the same or all layers. May be different, and only some of the layers may be the same, ”and“ multiple layers are different from each other ”means“ the constituent materials of each layer, the blending ratio of the constituent materials, and the thickness. At least one of them is different from each other ”.

Although the thickness before baking of a film-form baking material is not restrict | limited in particular, 10-200 micrometers is preferable, 20-150 micrometers is preferable, and 30-90 micrometers is more preferable.
Here, the “thickness of the film-like fired material” means the thickness of the entire film-like fired material. For example, the thickness of the film-like fired material consisting of a plurality of layers means all of the film-like fired material Means the total thickness of the layers.

  In the present specification, the “thickness” can be obtained by using a constant pressure thickness measuring instrument in accordance with JIS K7130 as a value represented by an average of thicknesses measured at five arbitrary locations.

(Peeling film)
A film-form baking material can be provided in the state laminated | stacked on the peeling film. In use, the release film may be peeled off and placed on the object to be sintered and bonded to the film-like fired material. The release film also has a function as a protective film for preventing damage to the film-like fired material and adhesion of dirt. The release film only needs to be provided on at least one side of the film-like fired material, and may be provided on both sides of the film-like fired material.

  As the release film, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, Polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine A transparent film such as a resin film is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. Moreover, the film which colored these, an opaque film, etc. can be used. Examples of the release agent include release agents such as silicone-based, fluorine-based, alkyd-based, olefin-based, and long-chain alkyl group-containing carbamate.

  The thickness of the release film is usually about 10 to 500 μm, preferably about 15 to 300 μm, and particularly preferably about 20 to 250 μm.

<Sintering metal particles>
The sinterable metal particles are metal particles that can be heated and processed as a fired film-like fired material to melt and bond the particles to form a sintered body. By forming a sintered body, it is possible to sinter-bond the film-like fired material and the article fired in contact therewith.

  Examples of the metal species of the sinterable metal particles include silver, gold, copper, iron, nickel, aluminum, silicon, palladium, platinum, titanium, barium titanate, oxides or alloys thereof, and silver and silver oxide. Is preferred. Only one kind of sinterable metal particles may be blended, or two or more kinds may be blended.

  The sinterable metal particles are preferably silver nanoparticles that are nano-sized silver particles.

The particle diameter of the sinterable metal particles contained in the film-like fired material is not particularly limited as long as it can exhibit the sinterability, but may be 100 nm or less, and 50 nm or less. It may be 30 nm or less. The particle diameter of the metal particles contained in the film-like fired material is a projected area equivalent circle diameter of the particle diameter of the metal particles observed with an electron microscope. Metal particles belonging to the above particle diameter range are preferable because of excellent sinterability.
The particle diameter of the sinterable metal particles contained in the film-like fired material is the number average of the particle diameters obtained for the particles having a projected area equivalent circle diameter of 100 nm or less of the particle diameter of the metal particles observed with an electron microscope. 0.1 to 95 nm, 0.3 to 50 nm, and 0.5 to 30 nm. The number of metal particles to be measured is 100 or more randomly selected per one film-like fired material.

  Before mixing the sinterable metal particles with the binder component and other additive components, disperse them beforehand in a high-boiling solvent with a high boiling point such as isobornyl hexanol or decyl alcohol in order to make the aggregate free of aggregates. May be. The boiling point of the high boiling point solvent may be, for example, 200 to 350 ° C. At this time, when a high-boiling solvent is used, since it hardly volatilizes at room temperature, the concentration of the sinterable metal particles is prevented from increasing, and workability is improved. Reagglomeration and the like are also prevented, and the quality may be improved. Examples of the dispersion method include kneader, three-roll, bead mill, and ultrasonic waves.

  In the film-like fired material of the embodiment, in addition to metal particles having a particle diameter of 100 nm or less (sinterable metal particles), non-sinterable metal particles having a particle diameter not exceeding 100 nm are further blended. Also good. The particle diameter of non-sinterable metal particles having a particle diameter exceeding 100 nm is the number of particle diameters obtained for particles having a projected area equivalent circle diameter exceeding 100 nm of the particle diameter of the metal particles observed with an electron microscope. The average may be greater than 150 nm and less than or equal to 50000 nm, may be 150 to 10,000 nm, and may be 180 to 5000 nm.

Examples of the metal species of the non-sinterable metal particles having a particle diameter exceeding 100 nm include those exemplified above, and silver, copper, and oxides thereof are preferable.
The metal particles having a particle diameter of 100 nm or less and the non-sinterable metal particles having a particle diameter exceeding 100 nm may be the same metal species or different metal species. For example, the metal particles having a particle diameter of 100 nm or less may be silver particles, and the non-sinterable metal particles having a particle diameter exceeding 100 nm may be silver or silver oxide particles. For example, the metal particles having a particle diameter of 100 nm or less may be silver or silver oxide particles, and the non-sinterable metal particles having a particle diameter exceeding 100 nm may be copper or copper oxide particles.

  In the film-like fired material of the embodiment, the content of metal particles having a particle diameter of 100 nm or less with respect to 100 parts by mass of the total mass of all metal particles may be 20 to 100 parts by mass, or 30 to 99 parts by mass. It may be 50 to 95 parts by mass.

The surface of the sinterable metal particles and / or non-sinterable metal particles may be coated with an organic substance. By having an organic coating, compatibility with the binder component is improved, particles can be prevented from agglomerating, and can be uniformly dispersed.
When the surface of the sinterable metal particles and / or non-sinterable metal particles is coated with an organic substance, the mass of the sinterable metal particles and non-sinterable metal particles is the value including the coating. To do.

<Binder component>
By blending the binder component, the fired material can be formed into a film shape, and tackiness can be imparted to the film-like fired material before firing. The binder component may be thermally decomposable that is thermally decomposed by heat treatment as firing of the film-like fired material.
Although a binder component is not specifically limited, Resin is mentioned as a suitable example of a binder component. Examples of the resin include acrylic resins, polycarbonate resins, polylactic acid, and polymerized cellulose derivatives, and acrylic resins are preferred. Acrylic resins include homopolymers of (meth) acrylate compounds, copolymers of two or more (meth) acrylate compounds, and copolymers of (meth) acrylate compounds and other copolymerizable monomers. included.

In the resin constituting the binder component, the content of the structural unit derived from the (meth) acrylate compound is preferably 50 to 100% by mass, and preferably 80 to 100% by mass with respect to the total amount of the structural unit. More preferably, it is 90-100 mass%.
Here, “derived” means that the monomer has undergone a structural change necessary for polymerization.

Specific examples of the (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl. (Meth) acrylate, pentyl (meth) acrylate, amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, Decyl (meth) acrylate, alkyl (meth) acrylates such as lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate;
Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) Hydroxyalkyl (meth) acrylates such as acrylates;
Phenoxyalkyl (meth) acrylates such as phenoxyethyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-propoxyethyl Alkoxyalkyl (meth) acrylates such as (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-methoxybutyl (meth) acrylate;
Polyethylene glycol mono (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxypolypropylene Polyalkylene glycol (meth) acrylates such as glycol (meth) acrylate, ethoxy polypropylene glycol (meth) acrylate, nonylphenoxy polypropylene glycol (meth) acrylate;
Cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, bornyl (meth) acrylate, isobornyl ( Cycloalkyl (meth) acrylates such as (meth) acrylate and tricyclodecanyl (meth) acrylate;
Examples thereof include benzyl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate. Alkyl (meth) acrylate or alkoxyalkyl (meth) acrylate is preferred, and particularly preferred (meth) acrylate compounds include butyl (meth) acrylate, ethylhexyl (meth) acrylate, lauryl (meth) acrylate, isodecyl (meth) acrylate, 2- Mention may be made of ethylhexyl (meth) acrylate and 2-ethoxyethyl (meth) acrylate.

In this specification, “(meth) acrylate” is a concept including both “acrylate” and “methacrylate”.
As the acrylic resin, methacrylate is preferable. When the binder component contains a structural unit derived from methacrylate, the time (A) and the time (B) have a relationship of A <B <A + 200 seconds, and a film-like fired material in which A <2000 seconds is obtained. Easy to obtain.

  In the resin constituting the binder component, the content of the structural unit derived from methacrylate is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, based on the total amount of the structural unit, 90 More preferably, it is -100 mass%.

  The other copolymerizable monomer is not particularly limited as long as it is a compound copolymerizable with the above (meth) acrylate compound. For example, (meth) acrylic acid, vinylbenzoic acid, maleic acid, vinylphthalic acid, etc. Unsaturated carboxylic acids; vinyl group-containing radical polymerizable compounds such as vinyl benzyl methyl ether, vinyl glycidyl ether, styrene, α-methyl styrene, butadiene, and isoprene.

The weight average molecular weight (Mw) of the resin constituting the binder component is preferably 1,000 to 1,000,000, and more preferably 10,000 to 800,000. When the weight average molecular weight of the resin is within the above range, it becomes easy to develop sufficient film strength and impart flexibility as a film.
In the present specification, “weight average molecular weight” is a polystyrene equivalent value measured by gel permeation chromatography (GPC) method unless otherwise specified.

The glass transition temperature (Tg) of the resin constituting the binder component can be obtained from calculation using the following Fox theoretical formula, which is preferably −60 to 50 ° C., and preferably −30 to 10 ° C. More preferably, it is more preferably −20 or more and less than 0 ° C. When Tg obtained from the Fox formula of the resin is not more than the above upper limit value, the adhesive force before firing between the film-like fired material and the adherend (eg, chip, substrate, etc.) is improved. On the other hand, when Tg calculated | required from the Fox formula of resin is more than the said lower limit, a film shape can be maintained and the film-like baking material can be pulled apart from a support sheet etc. more easily.
The Tg of the acrylic polymer is in accordance with the Fox formula from the weight ratio of the monomer of each polymer portion,
1 / Tg = (W1 / Tg1) + (W2 / Tg2) + ... + (Wm / Tgm)
W1 + W2 + ... + Wm = 1
The relationship is shown. In the formula, Tg represents the glass transition temperature of the polymer portion, and Tg1, Tg2,..., Tgm represent the glass transition temperature of each polymerization monomer. W1, W2,..., Wm represent the weight ratio of each polymerization monomer.
As the glass transition temperature of each polymerization monomer in the Fox formula, the values described in the Polymer Data Handbook and the Adhesive Handbook can be used.

The binder component may be thermally decomposable that is thermally decomposed by heat treatment as firing of the film-like fired material. The thermal decomposition of the binder component can be confirmed by a decrease in the mass of the binder component due to firing. In addition, although the component mix | blended as a binder component may be substantially thermally decomposed by baking, the total mass of the component mix | blended as a binder component does not need to be thermally decomposed by baking.
The binder component may have a mass after firing of 10% by mass or less, or 5% by mass or less, and 3% by mass or less with respect to 100% by mass of the binder component before firing. It may be.

  In addition to the above sinterable metal particles, non-sinterable metal particles and binder component, the film-like fired material of the embodiment includes sinterable metal particles, non-sintered materials within the range not impairing the effects of the present invention. Other additives that do not correspond to the binder metal particles and the binder component may be contained.

  Examples of other additives that may be contained in the film-like fired material of the embodiment include a solvent, a dispersant, a plasticizer, a tackifier, a storage stabilizer, an antifoaming agent, a thermal decomposition accelerator, and an antioxidant. Is mentioned. Only 1 type may be contained and 2 or more types of additives may be contained. These additives are not particularly limited, and those commonly used in this field can be appropriately selected.

<Composition>
The film-like fired material of the embodiment may be composed of sinterable metal particles, a binder component, and other additives, and the sum of these contents (mass%) may be 100 mass%. .
When the film-like fired material of the embodiment includes non-sinterable metal particles, the film-like fired material is made of sinterable metal particles, non-sinterable metal particles, a binder component, and other additives. The sum of these contents (mass%) may be 100 mass%.

In the film-like fired material, the content of the sinterable metal particles is preferably 10 to 98% by mass with respect to the total content of 100% by mass of all components other than the solvent (hereinafter referred to as “solid content”). 15-90 mass% is more preferable, and 20-80 mass% is further more preferable.
When the film-like fired material contains non-sinterable metal particles, the total content of the sinterable metal particles and the non-sinterable metal particles with respect to 100% by mass of the total solid content in the film-like fired material is 50-98 mass% is preferable, 70-95 mass% is more preferable, 80-90 mass% is further more preferable.

  2-50 mass% is preferable, as for content of the binder component with respect to the total content of 100 mass% of solid content in a film-form baking material, 5-30 mass% is more preferable, and 10-20 mass% is further more preferable.

  In the film-like fired material, the mass ratio of the sinterable metal particles to the binder component (sinterable metal particles: binder component) is preferably 50: 1 to 1: 5, and more preferably 20: 1 to 1: 2. 10: 1 to 1: 1 is more preferable. When the film-like fired material contains non-sinterable metal particles, the mass ratio of the sinterable metal particles and non-sinterable metal particles to the binder component ((sinterable metal particles + non-sinterable The metal particles): binder component) is preferably 50: 1 to 1: 1, more preferably 20: 1 to 2: 1, and even more preferably 9: 1 to 4: 1.

  When the film-like fired material has the composition shown above, the time (A) and the time (B) have a relationship of A <B <A + 200 seconds, and the film-like fired material in which A <2000 seconds is satisfied. Easy to obtain.

  The film-like fired material may contain a high boiling point solvent used when mixing sinterable metal particles, non-sinterable metal particles, a binder component and other additive components. The content of the high boiling point solvent is preferably 20% by mass or less, more preferably 15% by mass or less, and further preferably 10% by mass or less with respect to 100% by mass of the total mass of the film-like fired material. When the content of the high boiling point solvent is not more than the above upper limit value, the time (A) and the time (B) have a relationship of A <B <A + 200 seconds, and A <2000 seconds. A fired material is easily obtained. Moreover, in the differential thermal analysis curve (DTA curve), it is easy to obtain a film-like fired material having no endothermic peak in the time range from 0 second to 2160 seconds after the start of temperature increase.

<Time (A) / Time (B)>
The film-like fired material according to the embodiment is a thermogravimetric curve (TG curve) measured from 40 ° C. to 600 ° C. at a temperature rising rate of 10 ° C./min in an air atmosphere. From the time (A) and 0 seconds after the start of temperature increase in the differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in the air atmosphere using alumina particles as a reference sample. The maximum peak time (B) in the time range of 2160 seconds satisfies the relationship of A <B <A + 200 seconds, and A <2000 seconds.

The TG curve represents a change in the weight of the film-like fired material in the process of heat-treating the film-like fired material.
The DTA curve represents the differential heat change of the film-like fired material during the process of heat-treating the film-like fired material.

  Hereinafter, the state of the film-like fired material in the firing process, which is estimated from the TG curve and the DTA curve, will be described with reference to the drawings as appropriate.

FIG. 2 shows a film-like fired material 1 satisfying the relationship of A <B <A + 200 seconds and A <2000 seconds before firing (FIG. 2 (a)), during firing (FIG. 2 (b)), and after firing. It is sectional drawing which shows a mode that it estimates about (FIG.2 (c)).
The binder component 20 contained in the film-like fired material before firing (FIG. 2A) is reduced in weight by heating (FIGS. 2B to 2C), and this phenomenon is a TG curve. Appears as a negative slope at.
The binder component 20 contained in the film-like fired material before firing (FIG. 2A) is thermally decomposed by absorbing heat during heating, and is contained in the film-like fired material before firing (FIG. 2A). The sinterable metal particles 10 are melted by absorbing heat during heating (FIG. 2B), and then sintered while generating heat (FIG. 2C). This endothermic process is observed as a DTA curve, but when the sintering process proceeds sufficiently, the calorific value is large and the pyrolysis of the binder component 20 contained in the film-like fired material (FIG. 2 (a)). The heat absorption by melting of the sinterable metal particles 10 is greatly exceeded. That is, in the DTA curve obtained by measurement, only positive differential heat due to heat generation is observed and appears as a peak.

  The time (A) and the time (B) satisfy the relationship of A <B <A + 200 seconds, and A <2000 seconds means that the sinterable metal particles are heated in the heating time immediately following the decrease of the binder component. This is considered to mean that the melting and sintering of is completed. It is generally known that the firing temperature is related to the size of the metal particles, and the smaller the metal particles, the lower the firing temperature. Therefore, the film-like fired material 1 satisfying the relationship of A <B <A + 200 seconds and A <2000 seconds does not show aggregation or fusion between the sinterable metal particles at the start of sintering, and is in the form of fine particles. It is presumed that the sintered metal particles 10m melted as they are sintered.

3 does not satisfy the relationship of A <B <A + 200 seconds, and the firing material 1c having a time B longer than A + 200 seconds is before firing (FIG. 3 (a)), during firing (FIG. 3 (b)), It is sectional drawing which shows typically a mode that it estimates about after baking (FIG.3 (c)).
The binder component 21 contained in the film-like fired material before firing (FIG. 3A) also decreases in weight by heating (FIGS. 3B to 3C), and this phenomenon is also a TG curve. Appears as a negative slope at.
The binder component 21 contained in the film-like fired material before firing (FIG. 3 (a)) is also thermally decomposed by absorbing heat during heating, and then into the film-like fired material before firing (FIG. 3 (a)). The contained sinterable metal particles 11 cause melting by heat absorption and sintering by heat generation (FIG. 3C). The process of absorbing and generating heat of the sinterable metal particles 11 occurs almost at the same time because the binder component 21 is not present or is small even if it is present, but since the amount of heat generated by sintering is large, the DTA curve In, only a positive peak indicating an exothermic process appears.

  The fact that the time (A) and the time (B) do not satisfy the relationship of A <B <A + 200 seconds means that the sintering of the sinterable metal particles is not completed in the heating time immediately following the decrease of the binder component. It is thought that means. The firing temperature is related to the size of the metal particles, and the larger the metal particles, the higher the firing temperature. Therefore, for example, in the fired material 1c that does not satisfy the relationship of A <B <A + 200 seconds and the time B is longer than A + 200 seconds, it is estimated that the size of the sinterable metal particles is large at the stage of sintering. This is probably because the reduction of the binder component due to heating proceeds before the melting and sintering peaks of the sinterable metal particles, so that the sinterable metal particles 11 have a certain size at the start of sintering. It is considered that the time (B) is increased by sintering the metal particles in the form of lump.

Further, the inventors of the present invention have a film-like fired material in which time (A) and time (B) satisfy the relationship of A <B <A + 200 seconds, and A <2000 seconds, and have excellent shear adhesive strength after firing. I found out.
In a fired material that does not satisfy the relationship of A <B <A + 200 seconds and the time of B is longer than A + 200 seconds, the sinterable metal particles that have become agglomerated are sintered. It is conceivable that many unsintered portions remain, and the material after sintering is poor in adhesive strength (shear adhesive strength). Alternatively, it is conceivable that voids are likely to be generated at the adhesion interface with the adherend, and the adhesion strength is reduced by reducing the adhesion area.
Moreover, even if the relationship of A <B <A + 200 seconds is satisfied, the film-like fired material satisfying A ≧ 2000 seconds can reduce the productivity due to the extension of the tact time and increase the temperature required for firing. An adverse effect is possible.
On the other hand, in a film-like fired material satisfying the relationship of A <B <A + 200 seconds and A <2000 seconds, the sintered metal particles melted in the form of fine particles are fired in the presence of the binder component. By being bonded, the sinterable metals are uniformly and tightly bonded to each other, and it is considered that the adhesion strength of the sintered material is improved.

  The shear adhesive strength after firing of the film-like fired material can be measured by the method described in Examples.

  In the film-like fired material of the embodiment, the time (A) and the time (B) satisfy the relationship of A <B <A + 200 seconds, for example, satisfy the relationship of A <B <A + 100 seconds. It may be satisfied, A <B <A + 60 seconds may be satisfied, or A <B <A + 30 seconds may be satisfied.

  The maximum peak time (B) in the time range from 0 second to 2160 seconds after the start of temperature increase is a differential measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in an air atmosphere using alumina particles as a reference sample. In the thermal analysis curve (DTA curve), it is preferable that the maximum peak time is at 960 to 2160 seconds after starting the temperature increase, more preferably the maximum peak time is between 1080 and 2100 seconds after the start of temperature increase. More preferably, there is a maximum peak time between 1260 and 2040 seconds after the start.

<Time (A ') / Time (B')>
The film-like fired material of the embodiment is a thermogravimetric curve measured from 40 ° C. to 600 ° C. at a temperature rise rate of 10 ° C./min in an air atmosphere for the component obtained by removing the sinterable metal particles from the film-like fired material. In the (TG curve), the time (A ′) after the start of temperature increase with the largest negative slope and the sintering metal particles at a temperature increase rate of 10 ° C./min in the air atmosphere using alumina particles as a reference sample. In the differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C., the peak time observed in the shortest time among the peaks observed in the time range from 960 seconds to 2160 seconds after the start of temperature increase (B ′ ) Preferably satisfy the relationship B ′ <A ′.

The TG curve represents the change in the weight of the component excluding the sinterable metal particles from the film-like fired material during the heat treatment as firing.
The DTA curve represents the differential heat change of the sinterable metal particles in the process of heat treatment as firing.

  When the film-like fired material according to the embodiment includes non-sinterable metal particles, the film-like fired material according to the embodiment is obtained by removing the sinterable metal particles and the non-sinterable metal particles from the film-like fired material. Regarding the component, the time (A ′) after the start of temperature increase with the largest negative slope in the thermogravimetric curve (TG curve) measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in the air atmosphere The differential thermal analysis curve (DTA) of the sinterable metal particles and non-sinterable metal particles measured from 40 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in an air atmosphere using alumina particles as a reference sample. Curve), the peak time (B ′) observed in the shortest time among the peaks observed in the time range from 960 seconds to 2160 seconds after the start of temperature rise satisfies the relationship of B ′ <A ′. preferable.

Components obtained by removing the sinterable metal particles and non-sinterable metal particles from the film-like fired material containing the binder component contained in the film-like fired material before firing are reduced in weight by heating, This phenomenon appears as a negative slope in the TG curve.
Sinterable metal particles contained in the film-like fired material before firing are melted and sintered by heating, and the melting phenomenon appears as a negative peak in the DTA curve, and the sintering phenomenon appears as a positive peak in the DTA curve. .

  The fact that time (A ′) and time (B ′) satisfy the relationship of B ′ <A ′ means that the components distributed around the sinterable metal particles of the film-like fired material during the heat treatment process. This is considered to mean that the melting and sintering of the sinterable metal particles are started earlier than the timing of weight reduction. Therefore, the film-like fired material satisfying the relationship of B ′ <A ′ is isolated from each other by components distributed around the sinterable metal particles, and is easily melted in the form of fine particles, and the time (A ′) At this point, the collision frequency increases rapidly, and the sinterable metal particles melted in the form of fine particles are easily sintered. As a result, in the film-like fired material satisfying the relationship of B ′ <A ′, the sinterable metals are uniformly and tightly bonded to each other, and it is considered that the strength of the material after sintering is improved.

The time (A ′) and the time (B ′) are obtained by separating the sinterable metal particles and the components excluding the sinterable metal particles from the film-like fired material before firing. It can be determined from the TG curve and DTA curve for the sample.
Separation of the sinterable metal particles from the film-like fired material before firing and the remaining components excluding the sinterable metal particles can be performed, for example, by the following method.
First, after mixing a film-like fired material before firing and a sufficient amount of an organic solvent, this is allowed to stand for a sufficient time until the sinterable metal particles settle. The supernatant liquid is extracted with a syringe or the like, and the residue after drying at 120 ° C. for 10 minutes is collected, whereby the components excluding the sinterable metal particles from the film-like fired material can be collected. In addition, for the liquid containing the sinterable metal particles after extracting the supernatant liquid with the syringe or the like, a sufficient amount of time until the sinterable metal particles settle after mixing a sufficient amount of the organic solvent again, Allow to stand and extract the supernatant with a syringe. After mixing the organic solvent and allowing to stand and extracting the supernatant liquid 5 times or more, the remaining liquid was dried at 120 ° C. for 10 minutes, and the residue was collected to collect the sinterable metal particles. Is possible.

This is the same even when the film-like fired material of the embodiment contains non-sinterable metal particles, and the time (A ′) and time (B ′) are calculated from the film-like fired material before firing. A TG curve and a DTA curve for each sample separated by separating the sinterable metal particles and non-sinterable metal particles from the components excluding the sinterable metal particles and non-sinterable metal particles. Can be obtained from
Separation of the sinterable metal particles and non-sinterable metal particles from the film-like fired material before firing and the remaining components excluding the sinterable metal particles and non-sinterable metal particles is, for example, The following method can be used.
First, after a film-like fired material before firing and a sufficient amount of an organic solvent are mixed, this is allowed to stand for a sufficient time until the sinterable metal particles and non-sinterable metal particles settle. The supernatant liquid is extracted with a syringe or the like, and the residue after drying at 120 ° C. for 10 minutes is collected to remove the components obtained by removing the sinterable metal particles and non-sinterable metal particles from the film-like fired material. Can be sorted. In addition, a sufficient amount of organic solvent is mixed again with the liquid containing the sinterable metal particles and non-sinterable metal particles after the supernatant liquid is extracted with the above-described syringe or the like. And let it stand for a sufficient time until the non-sinterable metal particles settle, and extract the supernatant with a syringe or the like. The organic solvent was mixed and allowed to stand, and the supernatant liquid was removed five times or more, and then the remaining liquid was dried at 120 ° C. for 10 minutes to recover the residue, so that the sinterable metal particles and non-fired particles were recovered. It is possible to fractionate caustic metal particles.

  The solvent used here is preferably one that can dissolve the binder component and can be volatilized under the drying conditions at 120 to 250 ° C. for 10 minutes. Can be used. For example, hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, 2-propanol, isobutyl alcohol (2-methylpropan-1-ol) and 1-butanol; esters such as ethyl acetate; ketones such as acetone and methyl ethyl ketone Ethers such as tetrahydrofuran; amides (compounds having an amide bond) such as dimethylformamide and N-methylpyrrolidone.

<Endothermic peak>
The film-like fired material of the embodiment is a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a temperature rise rate of 10 ° C./min in the air atmosphere using the alumina particles as a reference sample for the film-like fired material. ), It preferably has no endothermic peak in the time range from 0 seconds to 2160 seconds after the start of temperature increase.

  The DTA curve represents the differential heat change of the film-like fired material in the process in which the film-like fired material is heat-treated as fired.

When an endothermic peak is observed in the DTA curve, the film-like fired material contains a component that changes (for example, evaporates) by absorbing heat from the film-like fired material from 0 to 2160 seconds after the start of temperature increase. It is possible. That is, it can be considered that the evaporation of the components has occurred and the heat of vaporization associated therewith is necessary. Or it shows that it contains many components that endotherm by heat absorption and exceeds the amount of heat generated by sintering.
Therefore, it is preferable that the film-like fired material of the embodiment has a small or no content of a component having a property of evaporating from the film-like fired material in 0 second to 2160 seconds after the start of temperature increase. Moreover, it is preferable that the content of the component which absorbs a large amount of heat in pyrolysis and hinders the heat generation process by sintering is small or not contained.

  Here, before measuring the DTA curve for a film-like fired material, it is recommended that the film-like fired material be pretreated such as drying so that moisture absorbed as impurities is not measured. Is done. Examples of the drying treatment condition include 110 ° C. for 4 minutes.

  In the DTA curve, since there is no endothermic peak in the time range from 0 seconds to 2160 seconds after the start of temperature rise, there is no possibility that the components distributed around the sinterable metal particles will decrease, and the sinterable metal particles Each of the particles tends to be isolated by the components distributed around. As a result, in a film-like fired material that does not have an endothermic peak in the time range from 0 seconds to 2160 seconds after the start of temperature rise in the DTA curve, the sinterable metal forms metal bonds uniformly and densely. Thus, the strength of the sintered material is likely to be improved. Moreover, the energy loss of energy required for baking is reduced, and baking in a favorable environment is realized. Moreover, it is thought that the shear adhesive force after baking of a film-form baking material improves by this.

  According to the film-like fired material of the above embodiment, the film-like fired material is excellent in thickness stability. Moreover, since the film-form baking material of embodiment contains a sinterable metal particle, it is excellent in thermal conductivity. Furthermore, the film-like fired material according to the embodiment satisfies the relationship of A <B <A + 200 seconds and exhibits an excellent shear adhesive force after firing because A <2000 seconds.

≪Method for producing film-like fired material≫
The film-like fired material can be formed using a fired material composition containing the constituent materials. For example, on the surface to be formed of the film-like fired material, by applying a fired material composition containing each component and a solvent for constituting the film-like fired material, and drying the solvent as needed to volatilize the solvent, A film-like adhesive can be formed at the target site.
The solvent preferably has a boiling point of less than 250 ° C., for example, n-hexane (boiling point: 68 ° C.), ethyl acetate (boiling point: 77 ° C.), 2-butanone (boiling point: 80 ° C.), n-heptane (boiling point: 98 ° C), methylcyclohexane (boiling point: 101 ° C), toluene (boiling point: 111 ° C), acetylacetone (boiling point: 138 ° C), n-xylene (boiling point: 139 ° C), dimethylformamide (boiling point: 153 ° C) and butylcarb Tall (boiling point: 230 ° C.) and the like. These may be used alone or in combination.

  Examples of the surface on which the film-like fired material is formed include the surface of a release film.

  The firing material composition may be applied by a known method, for example, an air knife coater, a blade coater, a bar coater, a gravure coater, a comma (registered trademark) coater, a roll coater, a roll knife coater, a curtain coater, or a die coater. And a method using various coaters such as a coater, a knife coater, a screen coater, a Meyer bar coater, and a kiss coater.

  The drying conditions of the fired material composition are not particularly limited, but when the fired material composition contains a solvent, it is preferable to heat dry, in this case, for example, 70 to 250 ° C., for example, 80 to 180 ° C., It is preferable to dry under conditions of 10 seconds to 10 minutes.

≪Film-like fired material with support sheet≫
The film-like fired material with support sheet of the embodiment includes the film-like fired material of the embodiment and a support sheet provided on at least one side of the film-like fired material. The support sheet is provided with a pressure-sensitive adhesive layer on the entire surface or on the outer periphery of the base film, and the film-like fired material is preferably provided on the pressure-sensitive adhesive layer. The film-like fired material may be provided in direct contact with the pressure-sensitive adhesive layer, or may be provided in direct contact with the base film. By taking this form, it can be used as a dicing sheet used when a semiconductor wafer is separated into elements. In addition, by using a blade or the like to separate into pieces together with the wafer, it can be processed as a film-like fired material having the same shape as the element, and a semiconductor element with a film-like fired material can be manufactured.

  Hereinafter, embodiments of the film-like fired material with a support sheet will be described. The schematic sectional drawing of the film-form baking material with a support sheet of embodiment is shown in FIG. 4 and FIG. As shown in FIG. 4 and FIG. 5, the film-like fired material 100 a, 100 b with the support sheet of the embodiment enables the film-like fired material 1 to be peeled on the inner peripheral part of the support sheet 2 having the adhesive part on the outer peripheral part. Temporarily worn. As shown in FIG. 4, the support sheet 2 is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer 4 on the upper surface of the base film 3, and the inner peripheral surface of the pressure-sensitive adhesive layer 4 is covered with a film-like baking material. The adhesive portion is exposed on the outer peripheral portion. Further, as shown in FIG. 5, the support sheet 2 may have a configuration having a ring-shaped pressure-sensitive adhesive layer 4 on the outer peripheral portion of the base film 3.

  The film-like fired material 1 is formed on the inner peripheral portion of the support sheet 2 in substantially the same shape as a workpiece (semiconductor wafer or the like) to be stuck. The support sheet 2 has an adhesive portion on the outer peripheral portion. In a preferred embodiment, the film-like fired material 1 having a smaller diameter than the support sheet 2 is concentrically laminated on the circular support sheet 2. The adhesive portion on the outer peripheral portion is used for fixing the ring frame 5 as illustrated.

(Base film)
The base film 3 is not particularly limited. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene / propylene copolymer, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene / vinyl acetate. Copolymer, ethylene / (meth) acrylic acid copolymer, ethylene / (meth) methyl acrylate copolymer, ethylene / (meth) ethyl acrylate copolymer, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer A film made of coalescence, polyurethane film, ionomer or the like is used. In the present specification, “(meth) acryl” is used to mean both acrylic and methacrylic.
When higher heat resistance is required for the support sheet, the base film 3 includes polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polymethylpentene. Can be mentioned. In addition, these cross-linked films and modified films by radiation and discharge can also be used. The base film may be a laminate of the above films.

  Moreover, these films can also be laminated | stacked or used in combination of 2 or more types. Furthermore, the thing which colored these films, or what gave printing etc. can be used. In addition, the film may be a sheet formed by extrusion molding of a thermoplastic resin, or may be a stretched film. A film obtained by thinning and curing a curable resin by a predetermined means is used. It may be broken.

  The thickness of a base film is not specifically limited, Preferably it is 30-300 micrometers, More preferably, it is 50-200 micrometers. By making the thickness of the base film within the above range, the base film is hardly broken even if cutting is performed by dicing. In addition, since sufficient flexibility is imparted to the film-like fired material with a support sheet, good sticking property to a workpiece (for example, a semiconductor wafer) is exhibited.

  The base film can also be obtained by applying a release agent to the surface and performing a release treatment. As the release agent used for the release treatment, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, and the like are used. In particular, alkyd, silicone, and fluorine release agents are heat resistant. This is preferable.

  In order to release the surface of the substrate film using the above release agent, the release agent is used without a solvent, or diluted or emulsified with a solvent, and a gravure coater, a Mayer bar coater, an air knife coater, a roll coater, etc. The substrate film on which the release agent is applied is applied at room temperature or under heating, or cured by electron beam, wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, etc. The laminate may be formed with

(Adhesive layer)
The support sheet 2 has an adhesive portion at least on the outer periphery thereof. The adhesive portion has a function of temporarily fixing the ring frame 5 at the outer peripheral portions of the film-like fired materials 100a and 100b with a support sheet, and it is preferable that the ring frame 5 can be peeled off after a required process. Accordingly, the pressure-sensitive adhesive layer 4 may be weakly adhesive, or may be energy-ray curable, whose adhesive strength is reduced by irradiation with energy rays. The re-peelable pressure-sensitive adhesive layer is made of various conventionally known pressure-sensitive adhesives (for example, rubber-based, acrylic-based, silicone-based, urethane-based, vinyl ether-based general-purpose pressure-sensitive adhesives, pressure-sensitive adhesives, energy ray curable type) Adhesive, thermal expansion component-containing adhesive, etc.).

  In the configuration shown in FIG. 5, a ring-shaped adhesive layer 4 is formed on the outer peripheral portion of the base film 3 to form an adhesive portion. At this time, the pressure-sensitive adhesive layer 4 may be a single-layer pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive, or may be one obtained by circularly cutting a double-sided pressure-sensitive adhesive tape including a pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive.

  Further, as shown in FIG. 4, the support sheet 2 is a pressure-sensitive adhesive sheet having a normal configuration having a pressure-sensitive adhesive layer 4 on the entire upper surface of the base film 3, and the inner peripheral surface of the pressure-sensitive adhesive layer 4 is a film. The adhesion part may be the structure which was covered with the shape baking material and was exposed to the outer peripheral part. In this case, the outer peripheral portion of the pressure-sensitive adhesive layer 4 is used for fixing the ring frame 5 described above, and a film-like fired material is laminated on the inner peripheral portion in a peelable manner. As the pressure-sensitive adhesive layer 4, a weakly-adhesive layer may be used as described above, or an energy ray-curable pressure-sensitive adhesive may be used.

  As the weak pressure-sensitive adhesive, an acrylic type or a silicone type is preferably used. In consideration of the peelability of the film-like fired material, the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 4 to the SUS plate at 23 ° C. is preferably 30 to 120 mN / 25 mm, and preferably 50 to 100 mN / 25 mm. Is more preferable, and 60 to 90 mN / 25 mm is more preferable. If the adhesive strength is too low, the adhesiveness between the film-like fired material 1 and the pressure-sensitive adhesive layer 4 becomes insufficient, and the film-like fired material and the pressure-sensitive adhesive layer are peeled off during the dicing process, or the ring frame falls off. There are things to do. On the other hand, if the adhesive strength is too high, the film-like fired material and the pressure-sensitive adhesive layer are excessively adhered to each other, which causes a pickup failure.

  In the support sheet having the configuration shown in FIG. 4, when an energy ray curable releasable pressure-sensitive adhesive layer is used, the region where the film-like fired material is laminated may be irradiated with energy rays in advance to reduce the adhesiveness. Good. At this time, the other regions may not be irradiated with energy rays, and may be maintained with a high adhesive force for the purpose of adhesion to the ring frame 5, for example. In order not to irradiate energy rays only to other regions, for example, an energy ray shielding layer is provided by printing or the like in regions corresponding to other regions of the substrate film, and energy rays are irradiated from the substrate film side. Just do it. Moreover, in the support sheet of the structure of FIG. 4, in order to strengthen the adhesion | attachment with the base film 3 and the adhesive layer 4, the surface in which the adhesive layer 4 of the base film 3 is provided may be sandblasted, if desired. Irregularizing treatment such as solvent treatment, or corona discharge treatment, electron beam irradiation, plasma treatment, ozone / ultraviolet irradiation treatment, flame treatment, chromic acid treatment, hot air treatment, or other oxidation treatment can be performed. Moreover, primer treatment can also be performed.

  Although the thickness of the adhesive layer 4 is not specifically limited, Preferably it is 1-100 micrometers, More preferably, it is 2-80 micrometers, Most preferably, it is 3-50 micrometers.

(Film-like fired material with support sheet)
The film-like fired material with a support sheet is formed by temporarily attaching the film-like fired material to the inner periphery of a support sheet having an adhesive part on the outer periphery. In the configuration example shown in FIG. 4, the film-like fired material 100a with a support sheet is laminated so that the film-like fired material 1 can be peeled on the inner peripheral portion of the support sheet 2 composed of the base film 3 and the pressure-sensitive adhesive layer 4. The pressure-sensitive adhesive layer 4 is exposed on the outer periphery of the support sheet 2. In this configuration example, it is preferable that the film-like fired material 1 having a smaller diameter than the support sheet 2 is laminated on the pressure-sensitive adhesive layer 4 of the support sheet 2 so as to be peeled in a concentric manner.

  The film-like fired material 100a with a support sheet having the above configuration is attached to the ring frame 5 in the pressure-sensitive adhesive layer 4 exposed on the outer periphery of the support sheet 2.

  Further, an annular double-sided tape or a pressure-sensitive adhesive layer may be separately provided on the margin for the ring frame (exposed pressure-sensitive adhesive layer in the outer peripheral portion of the pressure-sensitive adhesive sheet). The double-sided tape has a configuration of pressure-sensitive adhesive layer / core material / pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer in the double-sided tape is not particularly limited. For example, rubber-based, acrylic-based, silicone-based, polyvinyl ether, or the like is used. . The adhesive layer is affixed to the ring frame at the outer periphery when an element described later is manufactured. As the core material of the double-sided tape, for example, a polyester film, a polypropylene film, a polycarbonate film, a polyimide film, a fluororesin film, a liquid crystal polymer film and the like are preferably used.

  In the configuration example shown in FIG. 5, a ring-shaped adhesive layer 4 is formed on the outer peripheral portion of the base film 3 to form an adhesive portion. In FIG. 6, the perspective view of the film-like baking material 100b with a support sheet shown in FIG. 5 is shown. At this time, the pressure-sensitive adhesive layer 4 may be a single-layer pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive, or may be one obtained by circularly cutting a double-sided pressure-sensitive adhesive tape including a pressure-sensitive adhesive layer made of the above-mentioned pressure-sensitive adhesive. The film-like fired material 1 is detachably laminated on the inner peripheral part of the base film 3 surrounded by the adhesive part. In this configuration example, it is preferable that the film-shaped fired material 1 having a smaller diameter than the support sheet 2 is laminated on the base film 3 of the support sheet 2 so as to be concentrically peelable.

  The film-like fired material with a support sheet is a release film for the purpose of protecting the surface of either the film-like fired material and / or the adhesive part, or both, until they are used. May be provided.

  As a surface protective film (release film), it can also be obtained by applying a release agent to the surface of a base film such as polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polypropylene mentioned above and applying a release treatment. it can. As the release agent used for the release treatment, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, and the like are used. In particular, alkyd, silicone, and fluorine release agents are heat resistant. This is preferable.

  In order to release the surface of the substrate film using the above release agent, the release agent is used without a solvent, or diluted or emulsified with a solvent, and a gravure coater, a Mayer bar coater, an air knife coater, a roll coater, etc. The substrate film on which the release agent is applied is applied at room temperature or under heating, or cured by electron beam, wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, etc. The laminate may be formed with

  1-500 micrometers is preferable, as for the thickness of a film-form baking material with a support sheet, 5-300 micrometers is more preferable, and 10-150 micrometers is more preferable.

≪Method for producing film-like fired material with support sheet≫
The film-like fired material with a support sheet can be produced by sequentially laminating the above-described layers so as to have a corresponding positional relationship.
For example, when laminating a pressure-sensitive adhesive layer or a film-like fired material on a base film, a pressure-sensitive adhesive composition or a fired material composition containing a component and a solvent for constituting the film is applied onto the release film. The pressure-sensitive adhesive layer or film-like fired material is formed in advance on the release film by drying and volatilizing the solvent as necessary to form a film, and this formed pressure-sensitive adhesive layer or film What is necessary is just to bond the exposed surface on the opposite side to the side which is contacting the said peeling film of a baking material with the surface of a base film. At this time, the pressure-sensitive adhesive composition or the baking material composition is preferably applied to the release-treated surface of the release film. The release film may be removed as necessary after forming the laminated structure.

  For example, a film-like fired material with a support sheet in which a pressure-sensitive adhesive layer is laminated on a base film, and a film-like fired material is laminated on the pressure-sensitive adhesive layer (the support sheet is a laminate of the base film and the pressure-sensitive adhesive layer) In the case of producing a film-like fired material with a support sheet), the adhesive layer is laminated on the base film by the above-described method, and the components for constituting this separately on the release film and A film-shaped fired material is formed on a release film by applying a fired material composition containing a solvent, drying as necessary, and volatilizing the solvent to form a film. A film-like fired material with a support sheet is obtained by laminating the exposed surface of the film with the exposed surface of the pressure-sensitive adhesive layer laminated on the substrate and laminating the film-like fired material on the pressure-sensitive adhesive layer. Even when the film-like fired material is formed on the release film, the fired material composition is preferably applied to the release-treated surface of the release film, and the release film can be removed as necessary after forming the laminated structure. Good.

  In this way, all layers other than the base material constituting the film-like fired material with a support sheet can be laminated by a method in which the layers are formed in advance on the release film and bonded to the surface of the target layer. Accordingly, a layer employing such a process may be appropriately selected to produce a film-like fired material with a support sheet.

  In addition, after providing all the necessary layers, the film-like fired material with a support sheet may be stored in a state in which a release film is bonded to the surface of the outermost layer opposite to the support sheet.

≪Element manufacturing method≫
Next, a method for using the film-like fired material with a support sheet according to the present invention will be described taking as an example the case where the fired material is applied to the production of an element (for example, a semiconductor element).

  As one embodiment of the present invention, a method for producing a semiconductor element using a film-like fired material with a support sheet comprises a semiconductor wafer (workpiece) having a circuit formed on the surface by peeling the release film of the film-like fired material with a support sheet. ) Is attached to the back surface of the support sheet, and the following steps (1) to (2) may be performed in the order of (1) and (2). (4) may be performed in the order of (1), (2), (3), and (4).

Step (1): a step of dicing the semiconductor wafer (work) and the film-like fired material of the laminate in which the support sheet, the film-like fired material, and the semiconductor wafer (work) are laminated in this order,
Step (2): A step of peeling the film-like fired material and the support sheet to obtain an element with the film-like fired material,
Step (3): A step of attaching an element with a film-like fired material to the surface of the adherend,
Step (4): A step of firing the film-like fired material and joining the semiconductor element and the adherend.

Hereinafter, the case where the said process (1)-(4) is performed is demonstrated.
The semiconductor wafer may be a silicon wafer and a silicon carbide wafer, or may be a compound semiconductor wafer such as gallium / arsenic. Formation of a circuit on the wafer surface can be performed by various methods including conventionally used methods such as an etching method and a lift-off method. Next, the opposite surface (back surface) of the circuit surface of the semiconductor wafer is ground. The grinding method is not particularly limited, and grinding may be performed by a known means using a grinder or the like. At the time of back surface grinding, an adhesive sheet called a surface protection sheet is attached to the circuit surface in order to protect the circuit on the surface. In the back surface grinding, the circuit surface side (that is, the surface protection sheet side) of the wafer is fixed by a chuck table or the like, and the back surface side on which no circuit is formed is ground by a grinder. The thickness of the wafer after grinding is not particularly limited, but is usually about 20 to 500 μm. Thereafter, if necessary, the crushed layer generated during back grinding is removed. The crushed layer is removed by chemical etching, plasma etching, or the like.

  Next, the film-like fired material of the film-like fired material with the support sheet is pasted on the back surface of the semiconductor wafer. Then, process (1)-(4) is performed in order of (1), (2), (3), (4).

  The semiconductor wafer / film-like fired material / support sheet laminate is diced for each circuit formed on the wafer surface to obtain a semiconductor element / film-like fired material / support sheet laminate. Dicing is performed so as to cut both the wafer and the film-like fired material. According to the film-like fired material with a support sheet of the embodiment, since the adhesive force is exhibited between the film-like fired material and the support sheet at the time of dicing, chipping and element jumping can be prevented, and the dicing suitability is excellent. . The dicing is not particularly limited. For example, after dicing the wafer, the periphery of the support sheet (the outer periphery of the support) is fixed by a ring frame, and then a known method such as using a rotating round blade such as a dicing blade is used. For example, a method for dividing a wafer into individual pieces may be used. The cutting depth into the support sheet by dicing may be obtained by completely cutting the film-like fired material, and is preferably 0 to 30 μm from the interface between the film-like fired material and the support sheet. By reducing the amount of cut into the support sheet, melting of the pressure-sensitive adhesive layer and the base film constituting the support sheet due to friction of the dicing blade, generation of burrs, and the like can be suppressed.

  Thereafter, the support sheet may be expanded. When a film having excellent extensibility is selected as the base film of the support sheet, the support sheet has excellent expandability. The film-like fired material and the support sheet are peeled off by picking up the diced semiconductor element with the film-like fired material by a general-purpose means such as a collet. As a result, a semiconductor element having a film-like fired material on the back surface (semiconductor element with a film-like fired material) is obtained.

Subsequently, an element with a film-like fired material is attached to the surface of an adherend such as a substrate, a lead frame, or a heat sink.
Next, the film-like fired material is fired, and a substrate, a lead frame, an adherend such as a heat sink, and the element are sintered and joined. At this time, if the exposed surface of the film-like fired material of the semiconductor element with the film-like fired material is attached to an adherend such as a substrate, a lead frame, or a heat sink, the semiconductor wafer (work) and The adherend can be sintered and joined.

  The heating temperature for firing the film-like fired material may be appropriately determined in consideration of the type of the film-like fired material, etc., but is preferably 100 to 600 ° C, more preferably 150 to 550 ° C, and further preferably 250 to 500 ° C. preferable. The heating time may be appropriately determined in consideration of the type of film-like fired material and the like, but is preferably 1 to 60 minutes, more preferably 1 to 30 minutes, and further preferably 1 to 10 minutes.

  The firing of the film-like fired material may be performed by pressure firing in which the film-like fired material is fired under pressure. As an example, the pressurizing condition may be about 1 to 50 MPa.

  According to the element manufacturing method of the embodiment, a film-like fired material with high uniformity in thickness can be easily formed on the back surface of the element, and cracks after the dicing process and packaging are less likely to occur. In addition, according to the element manufacturing method of the embodiment, a semiconductor element with a film-like fired material can be obtained without individually attaching the film-like fired material to the back surface of the individualized semiconductor element, thereby simplifying the production process. Can be achieved. Then, the semiconductor element with the film-like fired material is placed on a desired adherend such as a device substrate and fired to sinter-bond the semiconductor element and the adherend via the film-like fired material. A semiconductor device can be manufactured.

  As one embodiment, a semiconductor element with a film-like fired material comprising a semiconductor element and the film-like fired material of the embodiment is obtained. As an example, the semiconductor element with a film-like fired material can be manufactured by the above-described element manufacturing method.

  In addition, in the said embodiment, although illustrated about the sintering joining of the semiconductor element of a film-form baking material, and its adherend, the sintering joining object of a film-like baking material is not limited to what was illustrated above, Sinter bonding is possible for various articles sintered in contact with the film-like fired material.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

<Manufacture of firing material composition>
The components used for the production of the fired material composition are shown below. Here, metal particles having a particle diameter of 100 nm or less are expressed as “sinterable metal particles”, and metal particles having a particle diameter exceeding 100 nm are expressed as “non-sinterable metal particles”.

(Sintering metal particle-containing paste material)
・ Arconano silver paste ANP-1 (Organic coated composite silver nanopaste, Applied Nanoparticles Laboratory Co., Ltd .: Alcohol derivative-coated silver particles, metal content 70 wt% or more, silver particles 60 wt% or more with an average particle size of 100 nm or less)
・ Arconano silver paste ANP-4 (Organic coated composite silver nanopaste, Applied Nanoparticles Laboratory Co., Ltd .: Alcohol derivative-coated silver particles, metal content of 80 wt% or more, average particle size of 100 nm or less of silver particles of 25 wt% or more)

(Binder component)
Acrylic polymer 1 (2-ethylhexyl methacrylate polymer, average molecular weight 280,000, L-0818, manufactured by Nippon Synthetic Chemical Co., Ltd., MEK diluted product, solid content 54.5% by mass, Tg: −10 ° C. (Fox theory Calculated value using formula)))
Acrylic polymer 2 (methyl acrylate / 2-hydroxyethyl acrylate copolymer, copolymer weight ratio 85/15, average molecular weight 370,000, N-4617, manufactured by Nippon Synthetic Chemical Co., Ltd., ethyl acetate / toluene = 1/1 Mixed solvent diluted product, solid content 35.7% by mass, Tg: 4 ° C. (calculated value using Fox's theoretical formula))

  In the formulation shown in Table 1 below, each component was mixed to obtain a fired material composition corresponding to Examples 1-2 and Comparative Examples 1-2. The value of each component in Table 1 represents parts by mass. Since the sinterable metal particle-containing paste material is sold containing a high boiling point solvent and remains in the film-like firing material after coating or drying, the components of the sinterable metal particle-containing paste material Includes these. Considering that the solvent in the binder component volatilizes during drying, it represents the mass part of solid content excluding the solvent component.

<Manufacture of film-like fired material>
The fired material composition obtained above is applied to one side of a release film (thickness 38 μm, SP-PET 381031, manufactured by Lintec Corporation), and dried at 110 ° C. for 4 minutes to have the thicknesses shown in Table 1. A film-like fired material was obtained.

<Method for separating sinterable metal particles and non-sinterable metal particles from film-like fired material and components excluding these>
After mixing the film-like fired material before firing and about 10 times the weight of organic solvent, this was allowed to stand for about 30 minutes until the sinterable metal particles and non-sinterable metal particles settled. . The supernatant liquid is extracted with a syringe and the residue after drying at 120 ° C. for 10 minutes is collected, so that the components excluding the sinterable metal particles and the non-sinterable metal particles are separated from the film-like fired material. did. Moreover, after mixing the organic solvent about 10 times as much as a film-form baking material with respect to the liquid containing the sinterable metal particle and non-sinterable metal particle after extracting supernatant liquid with the said syringe. This was allowed to stand for about 30 minutes until the sinterable metal particles and non-sinterable metal particles settled, and the supernatant was extracted with a syringe. The organic solvent was mixed and allowed to stand, and the supernatant liquid was removed five times, and then the remaining liquid was dried at 120 ° C. for 10 minutes, and then the residue was recovered to obtain sinterable metal particles and non-sintered Metal particles were collected.

<Evaluation of film-like fired material>
The following items were evaluated for the film-like fired material obtained above.

(Measurement of TG / DTA)
About the film-like fired material obtained above, using a thermal analysis measurement device (thermal analyzer TG / DTA simultaneous measurement device DTG-60, manufactured by Shimadzu Corporation), a reference sample with almost the same amount of alumina particles as the measurement sample In an air atmosphere, the temperature was increased from 40 ° C. to 600 ° C. at a heating rate of 10 ° C./min, and a TG curve and a DTA curve were obtained. The result of Examples 1-2 is shown to FIGS. 7-8, and the result of Comparative Examples 1-2 is shown to FIGS. Table 1 shows the time (A) after the start of temperature increase with the largest negative slope in the TG curve and the maximum peak time (B) in the time range from 0 seconds to 2160 seconds after the start of temperature increase in the DTA curve. Shown in
In addition, for the component obtained by removing the sinterable metal particles and the non-sinterable metal particles from the film-like fired material by the separation method, the time after the start of temperature increase (A Table 1 shows ') and the peak time (B') observed in the shortest time among the peaks observed in the time range from 960 seconds to 2160 seconds after the start of temperature increase in the DTA curve.

(Measurement of shear adhesive strength)
The shear adhesive strength after firing of the film-like fired material was measured by the following method.
The film-like fired material obtained above was cut into 10 mm × 10 mm, and this was pasted on the top surface of a cylindrical copper adherend having a height of 5 mm having a cross section of 10 mm in diameter, and a 5 mm diameter on it. A cylindrical copper adherend having a cross-section of 2 mm in height is placed, and pressure-fired under the following conditions (1) to (3) in an air atmosphere to obtain a test piece for measuring bonding adhesive strength. It was. At normal temperature, a force was applied from the shear direction to the bonding surface of this test piece at a speed of 6 mm / min to measure the strength when the bonded state was broken, and the measurement result of the test piece obtained under the following pressure firing conditions Among them, the average value of the conditions showing the highest bonding adhesive strength was used as the shear adhesive strength. The results are shown in Table 1.
(1) 300 ° C. for 3 minutes, 30 MPa,
(2) 350 ° C. for 3 minutes, 10 MPa,
(3) 400 ° C. for 3 minutes, 10 MPa

(Measurement of thickness)
According to JIS K7130, it measured using the constant-pressure thickness measuring device (The product name "PG-02" by the teclock company).

  The film-like fired materials of Examples 1 and 2 had higher shear adhesion than the fired materials of Comparative Examples 1 and 2.

  Each configuration in each embodiment, a combination thereof, and the like are examples, and the addition, omission, replacement, and other changes of the configuration can be made without departing from the spirit of the present invention. Further, the present invention is not limited by each embodiment, and is limited only by the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Film-like baking material, 1c ... Baking material, 10, 11 ... Sinterable metal particle, 20, 21 ... Binder component, 100 ... Film-like baking material with a support sheet, 2 ... Support sheet, 3 ... Base film, 4 ... Adhesive layer, 5 ... Ring frame

Claims (6)

A film-like fired material containing sinterable metal particles and a binder component,
In the thermogravimetric curve (TG curve) measured from 40 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in the air atmosphere, the time (A) after the start of temperature increase with the largest negative slope,
In a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in an air atmosphere using alumina particles as a reference sample, in the time range from 0 seconds to 2160 seconds after the start of temperature increase. Maximum peak time (B) of
Satisfies the relationship of A <B <A + 200 seconds, and A <2000 seconds. A negative slope in a thermogravimetric curve (TG curve) measured from 40 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in the air atmosphere for the component obtained by removing the sinterable metal particles from the film-like fired material. Is the time (A ′) after the start of temperature increase with the largest,
About the sinterable metal particles, 960 after starting the temperature increase in a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min in the air atmosphere using the alumina particles as a reference sample. Among the peaks observed in the time range of 2 to 2160 seconds, the peak time (B ′) observed in the shortest time,
The film-like fired material according to claim 1, satisfying a relationship of B ′ <A ′.   For the film-like fired material, a differential thermal analysis curve (DTA curve) measured from 40 ° C. to 600 ° C. at a rate of temperature increase of 10 ° C./min in an air atmosphere using alumina particles as a reference sample, 0 seconds after the start of temperature increase The film-like fired material according to claim 1 or 2, which does not have an endothermic peak in a time range of from 2 to 2160 seconds.   The film-like fired material according to any one of claims 1 to 3, wherein the sinterable metal particles are silver nanoparticles.   The film-like baking material with a support sheet provided with the film-like baking material as described in any one of Claims 1-4, and the support sheet provided in the at least one side of the said film-like baking material. The support sheet is provided with a pressure-sensitive adhesive layer on a base film,
The film-like fired material with a support sheet according to claim 5, wherein the film-like fired material is provided on the pressure-sensitive adhesive layer.

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