JP5830288B2 - Conductive paste and semiconductor device - Google Patents

Description

  The present invention relates to a conductive paste and a semiconductor device using the same.

  The conductive paste is generally composed of a thermosetting resin binder (binder) such as an epoxy resin and a conductive powder, and is used for circuit formation by adhesion, coating, and printing of various electronic components. The binder, which is a thermosetting resin, is thermally cured by the curing agent and becomes insoluble in the organic solvent, and is given heat resistance, moisture resistance, weather resistance, and the like.

  Also, in a semiconductor device, the process of connecting a semiconductor element (hereinafter also referred to as a semiconductor chip) such as an LED, IC, or LSI to a predetermined portion on a thin metal plate (lead frame) has an important effect on the long-term reliability of the element. This is one of the important steps. Conventionally, as this connection method, a method of brazing using a low melting point alloy (solder), a method of using a conductive paste, or the like is used.

  However, in the method using solder, the solder scatters and adheres to an electrode or the like, and the attached solder may corrode during long-term use and cause disconnection. On the other hand, the method using the conductive paste is superior in workability at a low temperature as compared with the solder method, and does not cause a problem of scattering to the electrode or the like.

  However, many of the conventional conductive pastes have insufficient heat resistance and moisture resistance after long-term use (long-term heat resistance and long-term moisture resistance), which often promotes corrosion of the electrode and causes disconnection failure. . In recent years, as electronic devices have become lighter, thinner and shorter, they are often used in automobiles and outdoor devices, and as a result, the conductive paste used in these electronic devices has long-term heat resistance, Long-term moisture resistance is strongly demanded.

  Therefore, for example, in order to improve long-term heat resistance, conductive pastes using polyfunctional epoxy resins such as trifunctional and tetrafunctional, and polynuclear epoxy resins having a naphthalene skeleton, anthracene skeleton, and the like have been developed. However, the conductive paste using the polyfunctional epoxy resin is inferior in workability because of its high reactivity, and the polynuclear epoxy resin has excellent initial heat resistance, but long-term heat resistance is insufficient.

  In addition, conductive pastes using other resin materials such as acrylic resins, polyurethane resins, and heat-resistant polyimide silicone resins have been developed instead of epoxy resins. However, in the case of using an acrylic resin or a polyurethane resin, although the weather resistance is improved, since these resins have low heat resistance, not only long-term heat resistance but also initial heat resistance is lowered. In addition, although heat resistance is improved with a heat-resistant polyimide silicone resin, the bonding strength between the semiconductor chip and the lead frame material in the semiconductor device, particularly long-term reliability, is not always sufficient. In order to solve this problem of adhesive strength, a compound having a compound having a benzotriazole skeleton has been developed, but depending on the type of the lead frame material, a sufficient improvement effect may not be obtained.

JP 2005-113059 A JP 2001-76534 A

  The present invention has been made in view of the above circumstances, has good workability, excellent heat resistance, moisture resistance, weather resistance, and highly reliable physical in bonding between a semiconductor element and various substrates, It is an object of the present invention to provide a conductive paste capable of electrical bonding and a highly reliable semiconductor device using such a conductive paste.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a conductive paste containing a soluble polyimide resin, a solvent, and silver powder having specific physical properties and shapes, and an apparatus using the same. The inventors have found that the above object can be achieved and have completed the present invention.

That is, the conductive paste according to one embodiment of the present invention includes (A) a soluble polyimide resin, (B) a solvent, and (C) a specific surface area (SA) of 0.3 to 1.3 m ² / g, a tap density (TD). containing flaky silver powder 3.0~6.0g / cm ^3, (a) component, (a-1) 3,3 ' , tetracarboxylic acids containing 4,4'-benzophenonetetracarboxylic acid anhydride an anhydride, and a diamine compound comprising (a-2) diaminodiphenyl ether, characterized in that it is a reaction product of (a-3) amino-modified silicone.

The semiconductor device according to another aspect of the present invention, the above conductive paste, the semiconductor element is characterized that you have been bonded to the semiconductor element support member.

  According to one embodiment of the present invention, workability is excellent, heat resistance, moisture resistance, weather resistance are excellent, and highly reliable physical and electrical bonding is possible in bonding between a semiconductor element and various base materials. In addition, according to another embodiment of the present invention, a highly reliable semiconductor device using such a conductive paste can be obtained.

It is sectional drawing which shows the semiconductor device of one Embodiment of this invention.

  Hereinafter, the present invention will be described in detail.

The conductive paste of the present invention comprises (A) a soluble polyimide resin, (B) a solvent, and (C) a specific surface area (SA) of 0.3 to 1.3 m ² / g, and a tap density (TD) of 3.0 to 6. An essential component is 0 g / cm ³ of flaky silver powder.

  The soluble polyimide resin (A) is used without being limited by its molecular structure, molecular weight or the like as long as it is soluble. In general, a product obtained by reacting (a-1) tetracarboxylic acid or an anhydride thereof, (a-2) a diamine compound and (a-3) a modified silicone is used.

  Examples of the tetracarboxylic acid (a-1) include pyromellitic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 2,3,3 ′, 4′-biphenyltetracarboxylic acid, 3 , 3 ′, 4,4′-benzophenone tetracarboxylic acid, 4,4′-oxydiphthalic acid, 3,3 ′, 4,4′-diphenylsulfone tetracarboxylic acid, 2,2′-bis (3,4-di (Carboxylphenyl) hexafluoropropane, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,4, 5,8-naphthalenetetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,4,5-cyclopentanetetracarbo Acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3 ′, 4,4′-bicyclohexyltetracarboxylic acid, 2,3,5-tricarboxycyclopentylacetic acid, 3,4-dicarboxy- 1,2,3,4-tetrahydronaphthalene-1-succinic acid and the like. As the component (a-1), one type may be used alone, or two or more types may be mixed and used. As the component (a-1), 3,3 ′, 4,4′-benzophenone tetracarboxylic acid anhydride is particularly preferable.

  Examples of the diamine compound of component (a-2) include metaphenylene diamine, paraphenylene diamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 2,6-diaminotoluene, 3,5-diaminotoluene, 1-methoxy-2,4-diaminobenzene, 1,4-diamino-2-methoxy-5-methylbenzene, 1,3-diamino-4,6-dimethylbenzene, 3,5-diaminobenzoic acid, 2,5 -Diaminobenzoic acid, 1,2-diaminonaphthalene, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3 -Diaminonaphthalene, 2,6-diaminonaphthalene, 1,4-diamino-2-methylnaphthalene, 1,5-diamino- -Methylnaphthalene, 1,3-diamino-2-phenylnaphthalene, 2,2-bis (4-aminophenyl) propane, 1,1-bis (4-aminophenyl) ethane, 4,4'-diaminodiphenylmethane, 3 , 3′-dimethyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, 3,3′-dimethyl-5,5′-diethyl-4 , 4′-diphenylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diphenylmethane, 4,4′-methylenebis (cyclohexylamine), 4,4′-methylenebis (3,3′-dimethyl- Cyclohexylamine), 2,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenylsulfide Phon, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminobenzanilide, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl ether, bis (4-aminophenyl) ) Diethylsilane, bis (4-aminophenyl) diphenylsilane, bis (4-aminophenyl) -N-methylamine, bis (4-aminophenyl) -N-phenylamine, 3,3′-diaminobenzophenone, 4, 4'-diaminobenzophenone, 2,6-diaminopyridine, 3,5-diaminopyridine, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3 ′ Dihydroxy-4,4′-diaminobiphenyl, o-toluidine sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, bis [4 -(4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy) Benzene, 1,3-bis (4-aminophenoxy) benzene, 9,10-bis (4-aminophenyl) anthracene, 9,9-bis (4-aminophenyl) fluorene, 2,2-bis (4-amino) Phenyl) hexafluoropropane, 2,2-bis (3-aminophenyl) hexafluoropropane, 1,1-bis 4-aminophenyl) -1-phenyl-2,2,2-trifluoroethane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino-4) -Methylphenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane and the like. These diamine compounds may be used individually by 1 type, and may mix and use 2 or more types. As the component (a-2), diaminodiphenyl ether is preferable.

  The modified silicone of component (a-3) is a solubility-imparting component, a diaminosilicone having an amino group at both ends of the molecular chain, a dicarboxyl silicone having a carboxylic acid group at both ends of the molecular chain, and an epoxy group at both ends of the molecular chain. And diepoxy silicone having Specific examples of such commercially available modified silicones include BY16-871 and BY16-853 manufactured by Toray Dow Corning Co., Ltd. as diaminosilicones, and Toray Dow Corning Co., Ltd. as dicarboxyl silicones. BY16-750 and the like, and die epoxy silicone include BY16-855 manufactured by Toray Dow Corning Co., Ltd. These modified silicones may be used alone or in combination of two or more. As the component (a-3), amino-modified silicone is preferable.

  In synthesizing the soluble polyimide resin, (a-1) tetracarboxylic acid or an anhydride thereof, (a-2) a diamine compound, and (a-3) a modified silicone in a solvent, for example, 80 ° C. or higher. The polymerization reaction is carried out at a temperature of When the reaction temperature is less than 80 ° C., the polymerization does not proceed sufficiently and there is a possibility that many low molecular weight components are produced. The reaction temperature is preferably 100 to 140 ° C., and the reaction time is usually 2 to 4 hours.

  The reaction is usually 0.2 to 0.8 mol, preferably 0.4 to 0.6 mol of (a-2) diamine compound with respect to 1.0 mol of (a-1) tetracarboxylic acid or anhydride thereof. And (a-3) the modified silicone is usually reacted in an amount of 0.2 to 0.8 mol, preferably 0.4 to 0.6 mol. The solvent used in the reaction is not particularly limited. For example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dioxane, γ-butyrolactone, 1,3-dimethyl-2 -Imidazolidinone or the like is used. The concentration of the solute such as (a-1) tetracarboxylic acid or its anhydride in the reaction solution is not particularly limited, but is usually 5 to 25%, preferably 10 to 20%.

  In the conductive paste of the present invention, other resins can be blended together with the (A) soluble polyimide resin for the purpose of stress relaxation and adhesion. Examples of other resins that can be used in combination include epoxy resins, polyester resins, polybutadiene resins, polyurethane resins, and xylene resins. These resins may be used alone or in combination of two or more. Moreover, the compounding quantity has preferable 30 mass parts or less with respect to 100 mass parts of (A) soluble polyimide resin. If it exceeds 30 parts by mass, voids may be generated in the cured product or the mechanical strength of the cured product may be reduced.

  (B) The solvent of a component can dissolve the said resin component, The thing similar to the solvent illustrated by the synthesis | combination of the soluble polyimide resin mentioned above can be used. That is, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dioxane, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone and the like are used. These solvents may be used alone or in combination of two or more. The solvent is preferably selected in consideration of the solubility, boiling point, etc. of the resin in accordance with conditions such as the solubility of the resin, the curing temperature, and the curing time.

  The blending amount of this (B) solvent is preferably in the range of 100 to 900 parts by mass, more preferably in the range of 150 to 400 parts by mass with respect to 100 parts by mass of the resin component. If the blending amount is less than 100 parts by mass, the resin may be precipitated due to the high molecular weight of the resin. Moreover, when it exceeds 900 mass parts, there exists a possibility that a void may generate | occur | produce in hardened | cured material or workability | operativity may fall.

The silver powder of component (C) has a specific surface area (SA) of 0.3 to 1.3 m ² / g, a tap density (TD) of 3.0 to 6.0 g / cm ³ , and has a flake shape. Various commercially available silver powders can be used.

If the specific surface area (SA) of the silver powder is 0.3 m ² / g or more, the shape retention of the conductive paste is good, and if it is 1.3 m ² / g or less, the long-term heat resistance of the conductive paste is improved. While being able to improve, the volume resistivity of the hardened | cured material of an electrically conductive paste can be kept low. On the other hand, when the specific surface area (SA) of the silver powder exceeds 1.3 m ² / g, the decomposition reaction of the polyimide resin on the surface of the silver powder tends to occur, and the adhesive force with the substrate may be reduced. The specific surface area of silver powder (SA) is preferably 0.5~1.0m ² / g, more preferably 0.6~0.8m ² / g.

On the other hand, if the tap density (TD) of the silver powder is 3.0 g / cm ³ or more, the volume resistivity of the cured product of the conductive paste can be kept low, and the tap density (TD) is 6.0 g / cm ^3. If it is below, the thixotropy of the conductive paste is good, and the occurrence of stringing at the time of applying the conductive paste is suppressed. The tap density of the silver powder (TD) is preferably 3.0~5.0m ² / g, more preferably 3.2~4.0m ² / g.

In addition, although silver powder can mix and use 2 or more types of silver powder from which specific surface area (SA) or tap density (TD) differs, in that case, the said mixture should just satisfy the said requirements. . That is, the specific surface area (SA) of the mixture may be 0.3 to 1.3 m ² / g and the tap density (TD) may be 3.0 to 6.0 g / cm ³ . Here, the specific surface area (SA) of the silver powder is B.I. E. T.A. The surface area per unit mass of the powder (unit: m ² / g) measured with a Quantachrome Monosorb, and the tap density (TD) is measured with a Tap-Pak Volumemeter. The mass per unit volume of the powder (unit: g / cm ³ ).

  The flaky silver powder of component (C) is preferably blended in a proportion of 65 to 95% by mass, and in a proportion of 70 to 93% by mass, based on the total solid content of the conductive paste. Is more preferable. (C) If the ratio of the flaky silver powder of a component is the range of 65-95 mass%, workability | operativity and the electroconductivity of hardened | cured material can be improved.

  In the conductive paste of the present invention, other conductive powder can be blended together with the (C) flaky silver powder. Examples of other conductive powders include nickel powder and gold powder. Further, silver powder other than the component (C), for example, spherical silver powder, amorphous silver powder, dendritic silver powder, and the like can be blended. The content of these other conductive powders is preferably 30 parts by mass or less with respect to 100 parts by mass of (C) flaky silver powder. When it exceeds 30 mass parts, workability | operativity falls and there exists a possibility that the volume resistance of hardened | cured material may increase.

  In the conductive paste of the present invention, in addition to the components described above, a coupling agent, a curing agent, a curing catalyst, an antifoaming agent, which is generally blended with this type of paste within a range that does not impair the effects of the present invention, A coupling agent, a colorant, a flame retardant, and other various additives can be blended as necessary. These may be used individually by 1 type, and may mix and use 2 or more types.

  The conductive paste of the present invention has sufficient additives such as the above-described soluble polyimide resin of component (A), solvent of component (B), silver powder of component (C), and a coupling agent blended as necessary. After mixing, the mixture can be easily prepared by further kneading with a disperser, kneader, three-roll mill, etc., and then defoaming. In addition, you may make it prepare by adding various components to this solution using the resin solution at the time of synthesize | combining the soluble polyimide resin of (A) component as it is.

  The conductive paste of the present invention has good workability and is excellent in heat resistance, moisture resistance, and weather resistance. In addition, when used as an adhesive for joining a semiconductor element and various base materials, highly reliable physical and electrical joining can be performed regardless of the type of the base material.

Next, the semiconductor device of the present invention will be described.
In the semiconductor device of the present invention, for example, the semiconductor element is mounted on the lead frame via the conductive paste of the present invention, and after the conductive paste is heated and cured, the lead portion of the lead frame and the electrode on the semiconductor element are connected. It can manufacture by connecting by wire bonding and then sealing these using sealing resin. Examples of the bonding wire include a wire made of copper, gold, aluminum, gold alloy, aluminum-silicon, or the like. Moreover, the temperature at the time of hardening an electrically conductive paste is 100-250 degreeC normally, and it is preferable to heat about 1-3 hours.

  FIG. 1 shows an example of the semiconductor device of the present invention obtained as described above, and a cured product of the conductive paste of the present invention between a lead frame 1 such as a copper frame and a semiconductor element 2. An adhesive layer 3 is interposed. Further, the electrode 4 on the semiconductor element 2 and the lead portion 5 of the lead frame 1 are connected by a bonding wire 6, and these are further sealed by a sealing resin 7. In addition, as thickness of the adhesive bond layer 3, about 10-30 micrometers is preferable.

  The semiconductor device of the present invention provides a cured product with good workability and excellent heat resistance, moisture resistance, and weather resistance, and can be physically and electrically bonded with high adhesive strength regardless of the type of substrate. Since the semiconductor element is bonded and fixed with a possible conductive paste, it has high reliability.

  As described above, the conductive paste of the present invention is useful as an adhesive for bonding a semiconductor element onto a semiconductor element support member. In addition, the conductive paste is widely used for bonding various electronic parts, coating, and circuit formation by printing. Can be used.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all. In the following description, “parts” means “parts by mass” unless otherwise specified. Moreover, the specific surface area (SA) and tap density (TD) of silver powder are the values measured by the following method.
[Specific surface area (SA)]
B. E. T.A. The surface area per unit mass of the powder (unit: m ² / g) was measured with a Quantachrome Monosorb.
[Tap density (TD)]
The mass per unit volume of the powder in the vibrated container was measured with a Tap-Pak Volumemeter (unit: g / cm ³ ).
The materials used in the following examples and comparative examples are as shown in Table 1.

Example 1
2.0 parts of tetracarboxylic acid anhydride (a) and 2.0 parts of tetracarboxylic acid anhydride (b), 1.5 parts of diamine compound (a) and 1.5 parts of modified silicone are mixed with an organic solvent (a ) 16 parts were dissolved and reacted to obtain a viscous resin solution. To this resin solution, 77 parts of flaky silver powder (c) was added and mixed, further kneaded with a kneader, and degassed under reduced pressure to prepare a conductive paste.
(Example 2)
A conductive paste was prepared in the same manner as in Example 1 except that the tetracarboxylic acid anhydride (c) was used in place of the tetracarboxylic acid anhydride (b).
(Example 3)
A conductive paste was prepared in the same manner as in Example 1 except that 0.5 part of the diamine compound (a) and 1.0 part of the diamine compound (b) were used instead of 1.5 parts of the diamine compound (a). .
Example 4
A conductive paste was prepared in the same manner as in Example 1 except that the flaky silver powder (d) was used instead of the flaky silver powder (c).
(Example 5)
A conductive paste was prepared in the same manner as in Example 1 except that the flaky silver powder (b) was used instead of the flaky silver powder (c).
(Example 6)
Conductivity was the same as in Example 1 except that 38.5 parts of flaky silver powder (b) and 38.5 parts of flaky silver powder (d) were used instead of 77 parts of flaky silver powder (c). A paste was prepared.

(Comparative Example 1)
A conductive paste was prepared in the same manner as in Example 1 except that the flaky silver powder (e) was used instead of the flaky silver powder (c).
(Comparative Example 2)
A conductive paste was prepared in the same manner as in Example 1 except that the flaky silver powder (a) was used instead of the flaky silver powder (c).
(Comparative Example 3)
Instead of the flaky silver powder (c), except for using a spherical-shaped silver powder (f) was prepared an electrically conductive paste in the same manner as in Example 1.
(Comparative Example 4)
A conductive paste was prepared in the same manner as in Example 1 except that the modified silicone was not blended and the amount of the diamine compound (a) was changed to 3 parts.
(Comparative Example 5)
3.5 parts of epoxy resin, 3.5 parts of curing agent, 0.2 part of curing catalyst, 3.0 parts of organic solvent (b) and 90 parts of flaky silver powder (c) are sufficiently mixed and further kneaded with a kneader. The conductive paste was prepared by performing degassing under reduced pressure.
(Comparative Example 6)
6 parts of epoxy-modified silicone resin, 1 part of curing agent, 0.2 part of curing catalyst, 3.0 parts of organic solvent (b) and 90 parts of flaky silver powder (c) are sufficiently mixed, and further kneaded with a kneader. And conducting degassing under reduced pressure to prepare a conductive paste.

  Characteristics (viscosity, thixotropy, workability) of the conductive paste obtained in each of the above Examples and Comparative Examples, and cured product characteristics (silver content, adhesive strength, adhesive strength maintenance ratio, long-term heat resistance, volume resistance) Rate and conductivity) were measured and evaluated by the following methods.

<Characteristics of conductive paste>
[Viscosity (η _0.5rpm )]
The viscosity of the conductive paste immediately after preparation was measured using an E-type viscometer (3 ° cone) at 25 ° C. and 0.5 rpm.
[Thixotropic properties]
Using an E-type viscometer (3 ° cone), the viscosity (η 5 _rpm ) was measured under the conditions of 25 ° C. and 5.0 _rpm, and the ratio to the viscosity (η _{0.5 rpm} ) measured above was η _{0.5 rpm} / η _{5 rpm} Was calculated.
[Workability]
It evaluated from the following expansibility and shape retainability.
(I) Spreadability When 0.1 mm ³ of conductive paste is applied on a copper frame whose surface is silver-plated, and a preparation (18 mm × 18 mm glass plate) is placed on top of it, and a load of 20 g is applied for 10 seconds. The diameter of the spread area of the conductive paste was measured and evaluated according to the following criteria. The measurement was performed at 25 ° C.
○: 7 mm or more (good)
Δ: 5 mm or less, less than 7 mm ×: less than 5 mm (defect)
(B) Shape retention The conductive paste was applied onto a copper frame whose surface was silver-plated, and the subsequent occurrence of coating sagging was examined and evaluated according to the following criteria. The measurement was performed at 25 ° C.
○: Not generated within 5 minutes after application ×: Generated within 5 minutes after application

<Hardened product characteristics>
[Initial connection strength]
A conductive paste was applied to a thickness of 10 μm on a copper frame whose surface was silver-plated, a 2 mm × 2 mm semiconductor chip (Si) was mounted on the copper frame, and heat cured at 200 ° C. for 60 minutes to prepare a connection sample. . About this connection sample, the die shear strength was measured at 25 degreeC using the die shear strength measuring apparatus by Nishishin Shoji Co., Ltd.
[Connection strength maintenance ratio]
The connection strength after the connection sample prepared in the same manner as described above was placed at a temperature of 200 ° C. for 500 hours, 1000 hours, and 1500 hours was measured in the same manner as in the case of the initial connection strength, and maintained from the initial connection strength. The rate was calculated.
[Long-term heat resistance]
From the connection strength maintenance rate after 1500 hours determined above, the following criteria were used for evaluation.
○: Connection strength maintenance rate of 30% or more Δ: Connection strength maintenance rate of 10% or more and less than 30% ×: Connection strength maintenance rate of less than 10% [volume resistivity]
A conductive paste is printed on a slide glass with a thickness of 10 μm, a width of 2 mm, and a length of 5 mm, and cured by heating at 200 ° C. for 60 minutes. The cured product is used with a digital multimeter manufactured by Nissho Precision Optical Co., Ltd. , Measured at 25 ° C.
[Conductivity]
Based on the volume resistivity determined as described above, the following criteria were used for evaluation.
○: Less than 1 × 10 ⁻⁴ Ω · cm Δ: 1 × 10 ⁻⁴ Ω · cm or more and less than 1 × 10 ⁻³ Ω · cm ×: 1 × 10 ⁻³ Ω · cm or more

  The composition of each conductive paste is shown in Table 2, and the measurement evaluation results of each characteristic are shown in Table 3 together with the characteristics of silver powder (specific surface area (SA) and tap density (TD)).

As is apparent from Table 3, the conductive pastes of the examples have good to substantially good characteristics in all of workability (spreadability, shape retention), initial adhesive strength, long-term heat resistance and conductivity. In particular, Examples 1 to 3 using silver powder having a tap density (TD) of 3.2 to 4.0 g / cm ³ had particularly good characteristics. On the other hand, in the comparative examples, although the initial adhesive strength, long-term heat resistance and electrical conductivity were good, none of the above properties were satisfied, such as poor workability (shape retention).

  DESCRIPTION OF SYMBOLS 1 ... Lead frame, 2 ... Semiconductor element, 3 ... Adhesive layer, 4 ... Electrode, 5 ... Lead part, 6 ... Bonding wire, 7 ... Sealing resin.

Claims (4)

(A) soluble polyimide resin, (B) solvent and (C) specific surface area (SA) 0.3-1.3 m ² / g, tap density (TD) 3.0-6.0 g / cm ³ flaky silver powder And (A) component is (a-1) a tetracarboxylic acid anhydride containing 3,3 ′, 4,4′-benzophenonetetracarboxylic acid anhydride, and (a-2) a diamine containing diaminodiphenyl ether A conductive paste, which is a reaction product of a compound and (a-3) amino- modified silicone.   The conductive paste according to claim 1, wherein the component (C) is contained in a proportion of 65 to 95% by mass with respect to the total solid content. The tap paste (TD) of the said (C) component is 3.0-5.0 g / cm < ³ >, The electrically conductive paste of Claim 1 or 2 characterized by the above-mentioned. The claims 1 to 3 according to any one of the conductive paste, a semiconductor device in which a semiconductor element is characterized that you have been bonded to the semiconductor element support member.

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