JP2021161441A - Metal-resin composite and method for producing the same - Google Patents

Abstract

To provide a high-reliability composite having a sintered metal particulate layer and a resin layer, and a method for producing the composite.SOLUTION: A composite disclosed herein is a composite of a metal layer composed of sintered metal particulates and a resin layer composed of a resin. The metal layer is at least partially combined with the resin layer. The resin layer has internal metal particles therein. At least some of the internal metal particles are sintered with the sintered metal particulates.SELECTED DRAWING: Figure 4

Description

The present invention relates to a bonded body including a sintered body layer made of metal fine particles made of gold, silver, palladium and the like, and a resin layer made of a resin. Furthermore, the present invention relates to a method for producing such a bonded body.

In recent years, a bonded body of a metal fine particle sintered body layer made of metal fine particles and a resin layer made of resin has been developed for various uses. For example, Patent Document 1 below describes that a bonded body of a copper fine particle sintered body layer and a polyimide film is used as a base material for a printed wiring board of a small electric device or the like. Then, in such a bonded body, one surface of the polyimide film is treated with alkali, a conductive ink containing copper fine particles is applied to the surface to form a coating film, the coating film is dried, and then fired. Manufactured by doing.

JP-A-2019-114680

As described above, the technique described in Patent Document 1 is a technique using copper fine particles, but at present, a bonded body provided with a metal fine particle sintered body layer made of not only copper but also a precious metal such as gold and silver. Is required. However, in the technique of Patent Document 1, since the bond with the resin is maintained by the metal oxide and the group derived from the metal oxide, the sintered body layer composed of various metal species including noble metal is formed. It seems difficult to obtain a bonded body having a high bonding strength. In addition, low-temperature sintered metal fine particles that can be sintered below the heat-resistant temperature of the resin have high sinterability, and the fine particles are sintered at an early stage of the firing process, so that they have reactivity and bondability with the resin layer. There was also a problem that it was difficult to realize a highly reliable joined body.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a highly reliable bonded body including a metal fine particle sintered body layer and a resin layer. Another object of the present invention is to provide a method for producing such a bonded body.

According to the present invention, a bonded body of a metal layer made of a metal fine particle sintered body (that is, a metal fine particle sintered body layer) and a resin layer made of a resin is provided. Further, at least a part of the metal layer is bonded to the resin layer, metal particles are contained in the resin layer, and at least a part of the internal metal particles is sintered with the metal fine particles. It is characterized by being sintered with the body. In the bonded body having such a structure, high bonding strength can be realized by bonding the metal layer and the resin layer and sintering the metal fine particles and the internal metal particles.
In addition, in the present specification and claims, the term "metal fine particles" means a group of a large number of fine particles (that is, parts) unless it particularly refers to a single particle unit. For example, the metal fine particles in the <metal fine particle dispersion> described later refer to metal fine particles as parts instead of one grain. In Japanese, it is ambiguous whether it is singular or plural, so it is defined as above to clarify the meaning of "metal fine particles".

In a preferred embodiment of the bonded body disclosed here, micropores are present on the interface between the metal layer and the resin layer toward the inside of the resin layer, and at least one of the micropores is present. The metal fine particle sintered body is contained in the portion, and here, the opening diameter of the micropores in the FE-SEM cross-sectional image showing the boundary surface is a, and the opening diameter of the micropores is from the center of the opening diameter a to the micropores. When the distance to the deepest part where the metal fine particle sintered body has penetrated is b', the opening diameter a is 0.5 μm or more and 10 μm or less, and the distance b'is 0.5 μm or more. exist. In the bonded body having such a configuration, since the metal fine particle sintered body in the micropores plays a role of a so-called anchor effect, high bonding strength can be realized.

More preferably, in the FE-SEM cross-sectional image showing the boundary surface, the opening diameter a is 0.5 μm or more and 10 μm or less, where b is the distance from the center of the opening diameter a to the deepest part of the micropores. Moreover, when 100 points or more of the micropores having a distance b of 0.5 μm or more are detected (randomly, 100 points or more are detected), 60% or more of the micropores have a distance b'of 0.5 μm or more. exist. In a bonded body having such a configuration, the anchor effect is more preferably exhibited, so that a higher bonded strength can be realized.

In a preferred embodiment of the bonded body disclosed here, the main constituent metal element of the metal fine particles constituting the metal fine particle sintered body is a noble metal element.
Since the noble metal fine particles are easy to sinter with each other, they are suitable as targets to which the technique disclosed here is applied.

In a preferred embodiment, the main constituent metal element of the metal fine particles constituting the metal fine particle sintered body is gold (Au).
Among the noble metal fine particles, gold fine particles are suitable as targets to which the technique disclosed here is applied because the fine particles are easily sintered with each other.

In a preferred embodiment of the bonded body disclosed herein, the resin comprises a thermosetting resin as a component.
According to the thermosetting resin, the technique disclosed here can be preferably realized.

In a preferred embodiment, the resin comprises a thermosetting epoxy resin as a component.
Among the thermosetting resins, the epoxy resin has high heat resistance, so that a highly reliable bonded body can be obtained.

Further, in a preferred embodiment of the bonded body disclosed here, the density of the metal layer is 80% or more.
When the metal layer has a high density as described above, a bonded body having a low volume resistivity and good conductivity can be obtained. The details of the "dense density" in the present specification and the claims will be described in detail in <Dense density of the metal layer>.

The present invention also provides a method for producing the conjugate disclosed herein. Specifically, it is a method for producing a bonded body of a metal layer made of metal fine particles having an imine compound held on the surface and a resin layer made of a resin.
The dispersion containing the metal fine particles is prepared, and the dispersion is applied to the surface of the molded body made of the resin in an uncured state (here, the metal particles are inherent in the molded body). ), The molded body coated with the dispersion is heated in a temperature range in which the metal fine particles can be sintered to form the metal layer, and the molded body is cured to form the resin layer. Including forming. According to such a joint manufacturing method, a highly reliable joint having a desired strength can be obtained.
In the present specification and claims, the "dispersion" is a mixture of fine metal particles, endogenous metal particles, a resin, or the like in a solvent, and is a paste-like composition, a slurry-like composition, or an ink-like composition. Objects, paints, etc. may also be included.

Further, in a preferred embodiment of the conjugate manufacturing method disclosed herein, the imine compound has the following structural formula:
R ⁰ R ¹ C = N- (CH ₂ ) -R ²
In this compound, R ⁰ is hydrogen, and R ¹ and R ² are hydrocarbon groups having 3 to 7 carbon atoms, respectively.
Such an imine compound having a relatively low molecular weight and a short hydrocarbon group (for example, alkylimine) can be easily desorbed by low-temperature calcination at 300 ° C. or lower, and thus has a highly dense metal layer. The joined body can be easily manufactured.

6 is a pyrolysis GCMS spectrum obtained for the gold fine particle powder material produced in the examples described later. It is the MS spectrum of the peak (■) of the imine compound in FIG. It is an FE-SEM observation image (50,000 times) of the gold fine particle powder material produced in the Example described later. It is an FE-SEM observation image (5,000 times) of the boundary surface between the gold fine particle sintered body layer and the gold particle-containing thermosetting epoxy resin layer which concerns on Example 2. FIG. It is an FE-SEM observation image (5,000 times) of the boundary surface between the gold fine particle sintered body layer and the gold particle-containing thermosetting epoxy resin layer which concerns on Example 5. FIG. It is an FE-SEM observation image (5,000 times) of the boundary surface between the gold fine particle sintered body layer and the gold particle-containing thermosetting epoxy resin layer which concerns on Comparative Example 1. It is an FE-SEM observation image (5,000 times) of the boundary surface between the gold particle sintered body layer and the gold particle-containing thermoplastic polyimide resin layer which concerns on Comparative Example 2.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The present invention can be carried out based on the contents disclosed in the present specification and common general technical knowledge in the art.
In addition, in this specification and claims, when a predetermined numerical range is described as A to B (A and B are arbitrary numerical values), it means A or more and B or less. Therefore, it includes the case where it is above A and below B.

<Metal particles>
The bonded body disclosed here and the metal fine particles in the method for producing the bonded body are not particularly limited as long as the effects of the present invention can be obtained. Typically, gold (Au), silver (Ag), palladium (Pd), platinum (Pt), rhodium (Rh) and the like, or alloys thereof can be mentioned. Further, from the viewpoint that it is suitable as an object to which the technique disclosed here is applied, it is preferable that the main constituent metal element is gold (Au).
Here, the main constituent metal element refers to a metal element that is the main constituent of the metal fine particles. The metal fine particles disclosed here are ideally composed of only metal elements, but may contain various metal elements and non-metal elements as impurities. The organic matter content in the total weight (100 wt%) of the metal fine particles (meaning the aggregate before firing) measured based on TG-DTA is approximately 2 wt% or less, further 1.5 wt% or less. Is preferable, and 1 wt% or less is particularly preferable.

The imine compound is retained on the surface of the metal fine particles in the method for producing a bonded body disclosed here. High dispersion stability can be obtained by retaining the imine compound on the surface of the metal fine particles.
As a method for producing such metal fine particles, a metal salt or a metal complex (for example, metal is gold) that is soluble in a predetermined alcohol solvent that is a raw material of the metal fine particles, as in the reaction system described in Examples described later. In this case, gold chloride acid (HAuCl ₄ ) and the like can be mentioned), a sufficient amount (for example, 3 molar equivalents or more) of alkylamine with respect to the metal, and an alcohol solvent capable of dissolving the raw material, for example, alkyl. Examples thereof include a method of preparing a mixture with alcohol and heating the mixture to, for example, 80 ° C. or higher. As a result, metal ions are reduced from the metal salt or complex to generate metal fine particles.
The reduction treatment time of the metal ion can be set as appropriate. There is no particular limitation, but for example, about 0.5 hour to 5 hours is preferable.
The recovery of the metal fine particles produced by the reduction treatment as described above may be the same as the recovery of the conventional metal particles, and is not particularly limited. Preferably, the metal fine particles formed in the liquid are settled and centrifuged to remove the supernatant. Preferably, a desired dispersion of metal fine particles can be obtained by repeating washing and centrifugation a plurality of times with an appropriate dispersion medium and dispersing the metal fine particles in the appropriate dispersion medium. Further, by adding a component such as a binder, a paste (slurry) -like composition (for example, a conductor paste for forming an electrode film or the like) can be prepared.

Preferably, the imine compound produced in the above reaction system and retained on the surface of the metal fine particles has a relatively small molecular weight, specifically, having about 10 or less carbon atoms, for example, 4 to 10 carbon atoms. Alkylimine having a hydrocarbon group is preferable. For example, structural formula: R ⁰ R ¹ C = N- (CH ₂ ) -R ²
It is a compound represented by. R ⁰ , R ¹ and R ² are mutually independent partially substituted or unsubstituted alkyl groups or hydrogens. Preferable examples include those in which R ⁰ is hydrogen and R ¹ and R ² are hydrocarbon groups having 3 to 9 (more preferably 3 to 7) carbon atoms, respectively. Such an imine compound having a relatively low molecular weight and a short hydrocarbon group (for example, alkylimine) can be easily desorbed by low-temperature calcination at 300 ° C. or lower, and thus has a highly dense metal layer. The joined body can be easily manufactured.
For example, in the imine compound of the above structural formula, R ⁰ is hydrogen, and R ¹ and R ² are CH ₃ (CH ₂ ) ₆ , CH ₃ (CH ₂ ) ₄ or CH ₃ (CH ₂ ) _{2, respectively.} Is a specific preferred example.

This type of imine compound having a relatively small molecular weight and a short chain length can be selectively (preferentially) produced by selecting the alcohol solvent and the primary amine used in the above reaction system.
For example, when octanol (CH ₃ (CH ₂ ) _{7 OH) is used as the alcohol solvent and octyl amine (CH 3} (CH ₂ ) ₇ NH ₂ ) is used as the primary amine, the imine compound produced is produced. In the above structural formula, R ⁰ can be hydrogen, and R ¹ and R ² can be CH ₃ (CH ₂ ) ₆ , respectively. Alternatively, in this reaction system, when the primary amine is _{replaced with butylamine (CH 3} (CH ₂ ) ₃ NH ₂ ), the resulting imine compound has R ⁰ being hydrogen and R in the above structural formula. ^At least one of 1 and R ² can be _{CH 3} (CH ₂ ) _2. Alternatively, in this reaction system, when the primary amine is _{replaced with hexylamine (CH 3} (CH ₂ ) ₅ NH ₂ ), the imine compound produced is that R ⁰ is hydrogen in the above structural formula. At least one of ^{R 1} and R ² can be _{CH 3} (CH ₂ ) _4.
As described above, in the above reaction system, the molecular weight of the produced imine compound (in other words ^{, the composition of R 0} , R ¹ , and R ² ) is appropriately different depending on the appropriate selection of the alcohol solvent and the amine compound to be used. Can be done.
The structure of the produced imine compound can be identified by measuring the pyrolysis GCMS spectrum, as is clear from the description of Examples described later.

Regarding the particle size distribution of the metal fine particles, the Z average particle size (DDLS) based on the dynamic light scattering (DLS) method and the average particle size (DSEM) based on the field emission scanning electron microscope image (FE-SEM image). The DDLS / DSEM ratio, which is the ratio of the above, is preferably 2 or less. Since the metal fine particles having such properties have properties particularly excellent in dispersibility, they can contribute to the miniaturization of electronic components and the thinning of electrodes in the field of electronic materials. Further, the metal fine particles having a relatively small average particle size such that the Z average particle size (DDLS) is 200 nm or less can further preferably advance the thinning of the electrode, the improvement of reliability, and the like. The DDLS is more preferably 150 nm or less, and particularly preferably 50 nm or more and 150 nm or less, for example.

<Metallic particle dispersion>
The metal fine particle dispersion in the bonded body manufacturing method disclosed here can be obtained by dispersing the metal fine particles in a dispersion medium composed of an appropriate aqueous solvent or organic solvent.
For example, a composition (conductor paste) prepared in the form of a paste is provided by dispersing metal fine particles in a predetermined organic solvent and further adding components such as a binder, a conductive material, and a viscosity modifier as needed. can do. As described above, since the conductor paste contains metal fine particles whose Z average particle size is controlled in the submicron region, a sufficiently thinned electrode can be preferably formed.
As the dispersion medium of the conductor paste, as long as it can satisfactorily disperse the conductive powder material as in the conventional case, the one used for the conventional conductor paste preparation can be used without particular limitation. .. For example, as organic solvents, petroleum hydrocarbons such as mineral spirits (particularly aliphatic hydrocarbons), cellulose polymers such as ethyl cellulose, ethylene glycol and diethylene glycol derivatives, toluene, xylene, butyl carbitol (BC), tarpineol and the like. One type or a combination of a plurality of types of high boiling point organic solvents can be used.

Examples of a dispersion medium suitable for preparing the metal fine particle dispersion include a cyclic alcohol having a hydroxyl group on the cyclic chain. High dispersion stability can be realized by containing the cyclic alcohol as a dispersion medium. Preferable examples include cyclic alcohols having a 5-membered to 8-membered ring. For example, tarpineol, mentanol (dihydroterpineol), menthol (2-isopropyl-5-methylcyclohexanol), cyclopentanol, cyclohexanol, cycloheptanol, and the like can be mentioned. These cyclic alcohols may be used alone or in combination of two or more. The content of the cyclic alcohol is not particularly limited, but 10 to 100% by mass of the entire dispersion medium is suitable, and 70 to 100% by mass is preferable.

<Resin>
The bonded body disclosed here and the resin in the method for producing the bonded body are not particularly limited as long as the effects of the present invention can be obtained, but from the viewpoint of obtaining a highly reliable bonded body, the glass transition temperature (Tg) is determined. Higher resins are preferably used. Specific examples thereof include a thermosetting polyimide resin and a thermosetting epoxy resin. The Tg of the thermosetting epoxy resin that can be used in the present invention is typically 100 to 150 ° C.

<Intrinsic metal particles>
The resin is characterized by containing metal particles (hereinafter, such metal particles are also referred to as "intrinsic metal particles"). By sintering the internal metal particles with the metal fine particle sintered body constituting the metal layer, the strength of the obtained bonded body is suitably improved.
The endogenous metal particles are not particularly limited as long as the effects of the present invention can be obtained, but those listed in the above description of the metal fine particles can be preferably used. Further, gold particles can be preferably used from the viewpoint of high sinterability and easy sintering with a metal fine particle sintered body constituting a metal layer.

<Denseness of metal layer>
In the present specification and claims, "denseness" is defined by "Image Pro", an image analysis software manufactured by Media Cybernetics, from a 10,000-fold FE-SEM cross-sectional image showing an object (for example, a metal layer). The area of the black void portion (that is, the hollow portion) is obtained, and it means a value calculated as density (%) = 1- (void area / total area)%. A metal layer having a high density has a low volume resistivity and can exhibit good conductivity.
The density is preferably 80% or more, more preferably 85% or more, further preferably 90% or more, and particularly preferably 95% or more (the upper limit of the density is 100%). ).

<Micropores>
In the present specification and claims, a, b, and b'are used as parameters representing the mode of the micropores. a is the opening diameter of the micropores in the FE-SEM cross-sectional image showing the boundary surface between the metal layer and the resin layer, or between the metal particles existing in the resin opening at the boundary surface (that is, between the internal metal particles). ) Can also be referred to as the distance (see Fig. 4 etc.). Further, b is the distance from the center of the opening diameter a to the deepest part of the micropores, or from the center of the opening of the micropores through the metal fine particle sintered body in the opening to the deepest part in the opening. It can also be referred to as the length of the line segment connecting the. If the shape inside the opening is complicated and one line segment cannot represent the length to the deepest part, another line segment is added and the total of those line segments is b. .. Then, b'is the distance from the center of the opening diameter a to the deepest portion in which the metal fine particle sintered body has penetrated in the fine pores (see FIG. 4 and the like). As with b, if the shape inside the opening is complicated and one line segment cannot represent the length to the portion where the metal sintered body has penetrated, add another line segment. Let b'be the sum of those line segments. Here, preferably, the value of a is 0.5 μm to 10 μm, and the value of b'is 0.5 μm to 10 μm. Further, a may be 0.5 μm to 3 μm and b'may be 0.5 μm or more, a may be 1 μm to 3 μm, and b'may be 1 μm or more. It may be 2 μm to 3 μm and b'may be 2 μm or more.

Hereinafter, as an example of the bonded body disclosed here, an example relating to a bonded body of a gold fine particle sintered body layer and a gold particle-containing thermosetting epoxy resin layer will be described, but such examples limit the present invention. It is not intended to be done.

<1. Production example of gold fine particles>
50 mL of octanol (product of Fuji Film Wako Pure Chemical Industries, Ltd.) was added to 20.5 g of chloroauric acid tetrahydrate (product of Wako Pure Chemical Industries, Ltd.), and the obtained solution was cooled and stirred in an ice bath.
Next, n-octylamine (a product of Fuji Film Wako Pure Chemical Industries, Ltd.), which has 10 molar equivalents with respect to the gold content, is gradually added to the above solution while suppressing heat generation, and chloroauric acid-octylamine is added little by little. A complex-forming solution was prepared.
This complex-forming solution was subjected to a reduction treatment in which the complex-forming solution was heated in an oil bath at 140 ° C. for 3 hours in an air atmosphere to reduce gold ions and synthesize gold fine particles.
Then, the reaction solution was naturally cooled, industrial alcohol (Amanaka Chemical Industry product) was added, gold fine particles were allowed to settle, and the supernatant was removed by decantation. After repeating this operation three times, industrial alcohol was added and centrifugation at 3000 rpm for 3 minutes was performed twice or more (here, three times) to remove the supernatant. Then, it was dried at room temperature for 12 hours to obtain a dry powder material composed of gold fine particles.

<2. Evaluation test of gold fine particles>
(1) Characteristic characteristics of gold fine particles Using a field emission scanning electron microscope (FE-SEM: Hitachi High-Technologies Corporation, S-4700), gold fine particles in the powder material were observed (see FIG. 3). ). Specifically, 5 images were randomly extracted from a 100,000-fold field of view or a 50,000-fold field of view, and the particle sizes of 40 independent particles were measured, for a total particle size of 200 particles. The average particle size (DSEM) was calculated from. The results are shown in the corresponding columns of Table 1.

Further, for the above powder material, a sample having an appropriate concentration was prepared by ultrasonic dispersion using Zetasizer Nano ZS (a product of Malvern Panasonic) and N, N-dimethylformamide (DMF) as a dispersion medium. DLS measurement was performed at ° C., and Z average particle size (DDLS) was calculated based on a general cumulant method. The results are shown in the corresponding columns of Table 1.

Further, the above powder material was subjected to thermal analysis of gold fine particles (dry powder material) using a thermogravimetric measuring device (Rigaku Co., Ltd. product, TG-DTA / H). Specifically, about 20 mg of the above powder material was heated from room temperature to 400 ° C. at a rate of 10 ° C./min, and the thermal behavior when held at 400 ° C. for 50 minutes was observed. The weight reduction rate at this time was defined as the organic matter content in the total weight (100 wt%) of the gold fine particles (dry powder). The results are shown in the corresponding columns of Table 1.

(2) Detection of imine compound The above powder material was analyzed using a pyrolysis GCMS apparatus (manufactured by Shimadzu Corporation, GCMS-QP2010 Ultra).
Specifically, about 20 mg of dry powder of gold fine particles was heated at 300 ° C. for 18 seconds for thermal decomposition, and the gas component generated from the sample was measured by GCMS. The column used was Ultra ALLOY ± 5 (UA5-30M-0.25F) manufactured by Frontier Lab, and the column oven temperature was raised from 40 ° C to 320 ° C at a rate of 10 ° C / min, and the temperature was raised at 320 ° C for 32 minutes. Retained. The electron impact method (EI method) was used as the ionization method of the mass spectrometer.
The obtained pyrolysis GCMS spectrum is shown in FIG. In addition, the MS spectrum of the detected peak of the imine compound (peak in the corresponding pyrolysis GCMS spectrum) is shown in FIG.

The above-mentioned imine compounds identified were as follows.
[Imine compound]
Structural formula: R ⁰ R ¹ C = N- (CH ₂ ) -R ²
In the imine compound represented by, R ⁰ is hydrogen, and R ¹ and R ² are CH ₃ (CH ₂ ) ₆ , respectively. Hereinafter, it is referred to as imine compound A.
-Identification method Since the MS spectrum data of the above-mentioned imine compound did not exist in the GCMS library, the above-mentioned imine compound (R ⁰ is hydrogen and R ¹ and R ² are CH ₃ (CH ₂ ), respectively). Identification was performed with reference to the MS spectrum data of the imine compound ( _2).

As shown in Table 1, it was confirmed that the gold fine particles in the powder material had a DDLS / DSEM of 2 or less and had good dispersibility. Further, the Z average particle size (DDLS) was 150 nm or less, and it was confirmed that the powder material is a good powder material that contributes to the miniaturization of electronic components and the thinning of electrodes. When the total weight of the gold fine particles (dry powder) was 100 wt%, the organic matter content (here, the content of the imine compound and the like present on the surface of the gold fine particles) was 0.61 wt%. Therefore, since the amount of the imine compound adsorbed on the surface of the gold fine particles is small, the volume change due to burning through during firing is small, and it is considered that a sintered body having high density can be obtained.
Further, as shown in the corresponding column of Table 1, in the above powder material, a large exothermic peak (derived from oxidation) at 200 ° C. or higher, which is observed in gold fine particles in which alkylamine is retained, is detected in TG-DTA. Not (TG-DTA curve not shown). Then, it was confirmed that the main component in the thermal decomposition GCMS at 300 ° C. was an imine compound (alkylimine compound: see the above structural formula). This means that the molecules of the organic substance existing on the surface of the gold fine particles are converted from the alkylamine to the alkylimine compound in the reaction system in which the gold fine particles are synthesized, and the amine added to the reaction system hardly remains. It is shown that.

<3. Production example of gold fine particle dispersion>
Mentanol, which is a cyclic alcohol, was added to the powder material as a dispersion medium, and the mixture was allowed to stand for 3 hours or more. Then, the solvent was replaced by centrifugation.
Mentanol was added to the obtained wet powder so that the weight of the gold fine particles was 80 to 90 wt% of the total amount, and the mixture was mixed and dispersed by a rotation / revolution mixer to prepare a gold fine particle dispersion.

<4. Production example of thermosetting epoxy resin paint containing gold particles>
A thermosetting epoxy resin paint containing gold particles was prepared by dissolving a thermosetting epoxy resin in Tarpineol C and kneading gold particles and a novolak type phenol resin which is a curing agent (in the following description, in the following description, Such paint is also simply referred to as "epoxy resin paint").

<5. Production example of a bonded body including a gold fine particle sintered body layer and a gold particle-containing thermosetting epoxy resin layer>
Example 1:
The epoxy resin paint was applied onto a tungsten substrate and dried at 60 ° C. for 1 hour. As a result, a molded product made of a gold particle-containing thermosetting epoxy resin (hereinafter, also simply referred to as “epoxy resin molded product”) was formed on the tungsten substrate. At this time, the epoxy resin molded product lost its fluidity and was weakly bonded to the tungsten substrate. Subsequently, the gold fine particle dispersion was applied onto the surface of the epoxy resin molded product, dried at 60 ° C. for 1 hour, heated at 10 ° C./min, heat-treated at 250 ° C. for 30 minutes, and sintered. The epoxy resin molded product was cured. As a result, a tungsten-gold particle-containing thermosetting epoxy resin layer-gold fine particle sintered body layered body (hereinafter, also simply referred to as "bonded body") was obtained.
Example 2:
The same as in Example 1 except that the heat treatment conditions after the gold fine particle dispersion was applied onto the surface of the epoxy resin molded product and dried were raised at 10 ° C./min and heated at 280 ° C. for 50 minutes. Was performed. As a result, a conjugate was obtained.
Example 3:
The same as in Example 1 except that the heat treatment conditions after the gold fine particle dispersion was applied onto the surface of the epoxy resin molded product and dried were set to a temperature rise of 10 ° C./min and 30 minutes at 300 ° C. Was performed. As a result, a conjugate was obtained.
Example 4:
The epoxy resin paint was applied onto a tungsten substrate and dried at 130 ° C. for 15 minutes. As a result, a molded product made of a gold particle-containing thermosetting epoxy resin (that is, an “epoxy resin molded product”) was formed on the tungsten substrate. At this time, the epoxy resin molded product lost its fluidity and was weakly bonded to the tungsten substrate. Subsequently, the gold fine particle dispersion was applied onto the surface of the epoxy resin molded product, dried at 60 ° C. for 1 hour, heated at 10 ° C./min, heat-treated at 250 ° C. for 30 minutes, and sintered. The epoxy resin molded product was cured. As a result, a conjugate was obtained.
Example 5:
The same as in Example 4 except that the heat treatment conditions after the gold fine particle dispersion was applied onto the surface of the epoxy resin molded product and dried were raised at 10 ° C./min and heated at 280 ° C. for 50 minutes. Was performed. As a result, a conjugate was obtained.
Example 6:
The same as in Example 4 except that the heat treatment conditions after the gold fine particle dispersion was applied onto the surface of the epoxy resin molded product and dried were set to a temperature rise of 10 ° C./min and 30 minutes at 300 ° C. Was performed. As a result, a conjugate was obtained.

Comparative Example 1:
The epoxy resin coating was applied onto a tungsten substrate, dried at 130 ° C. for 15 minutes, and then heat-treated at 180 ° C. for 1 hour to cure the epoxy resin. At this time, the obtained gold particle-containing thermosetting epoxy resin layer (hereinafter, also simply referred to as “epoxy resin layer”) was in a state of being bonded onto the tungsten substrate. Subsequently, the gold fine particle dispersion was applied onto the surface of the epoxy resin layer, dried at 60 ° C. for 1 hour, heated at 10 ° C./min, heat-treated at 280 ° C. for 50 minutes, and sintered. .. As a result, although a bonded body was obtained, as can be seen from the FE-SEM cross-sectional image (FIG. 6), the bonded body was mainly sintered with gold fine particles and gold particles contained in the epoxy resin. It was due to. In such a joining mode, it is difficult to obtain high joining strength because the area of the joining surface is small.

<6. Production example of a thermoplastic polyimide resin paint containing gold particles>
A gold particle-containing thermoplastic polyimide resin paint was prepared by dissolving a thermoplastic polyimide resin in γ-butyrolactone and kneading gold particles (in the following description, such a paint is simply referred to as "polyimide resin paint". Also called).

Comparative Example 2:
The above-mentioned polyimide resin paint was applied onto a tungsten substrate and dried at 60 ° C. for 1 hour. As a result, a molded product made of a gold particle-containing thermoplastic polyimide resin (hereinafter, also simply referred to as “polyimide resin molded product”) was formed on the tungsten substrate. At this time, the solvent in the polyimide resin paint remained on the polyimide resin molded product, and it was in a flexible state, and was weakly bonded to the tungsten substrate. Subsequently, the gold fine particle dispersion is applied onto the surface of the polyimide resin molded product, dried at 60 ° C. for 1 hour, heated at 10 ° C./min, heat-treated at 280 ° C. for 50 minutes, sintered and the polyimide. The resin molded body was solidified. As a result, although a bonded body was obtained, as can be seen from the FE-SEM cross-sectional image (FIG. 7), the bonded body was mainly bonded to the gold fine particle sintered body layer and the gold particle-containing thermosetting epoxy resin layer. It was a junction with. In such a joining mode, it is difficult to obtain high joining strength.

<7. Direct formation of gold fine particle sintered body layer on the substrate>
Comparative Example 3:
The gold fine particle dispersion was coated on a glass substrate by squeezing it with a rubber squeegee using a metal mask of 1 cm × 1 cm × 100 μm. Then, after drying at 60 ° C. for 1 hour, heat treatment was performed at 300 ° C. for 30 minutes. As a result, the obtained gold fine particle sintered body layer did not adhere to the glass substrate and became a single film.
Comparative Example 4:
The same operation as in Comparative Example 4 was performed except that the gold fine particle dispersion was applied onto a tungsten substrate. As a result, the obtained gold fine particle sintered body layer did not adhere to the glass substrate and became a single film.
Comparative Example 5:
The same operation as in Comparative Example 4 was performed except that the gold fine particle dispersion was applied onto a gold substrate. As a result, the obtained gold fine particle sintered body layer did not adhere to the gold substrate and became a single film.

<8. Evaluation test of the joint>
[Tape peeling test]
A peeling test was conducted by attaching a cellophane tape to the joints obtained in Examples 1 to 6 and peeling them off. The test results are shown in the corresponding columns of Table 2.

[Evaluation of the density of the gold fine particle sintered body layer]
Ion milling of the cross sections of the joints obtained in Examples 1 to 6 was performed. Then, the area of the black void portion (that is, the hollow portion) is obtained from the obtained 10,000-fold FE-SEM cross-sectional image showing each ion milling polished surface by the image analysis software "Image Pro" manufactured by Media Cybernetics. , Dense density (%) = 1- (void area / total area)%. The results are shown in the corresponding columns of Table 2.

[Observation of micropores]
The micropores existing at the interface between the gold fine particle sintered body layer and the gold particle-containing thermosetting epoxy resin layer of the bonded body according to Examples 1 to 6 were evaluated. First, in a 5,000-fold FE-SEM cross-sectional image showing each boundary surface, the opening diameter of the micropores existing in the boundary surface is defined as a, and the distance in which the thermosetting epoxy resin penetrates in the micropores is defined as b'. When this was done, it was confirmed that the opening diameter a was 0.5 μm or more and 10 μm or less, and the distance b'was 0.5 μm or more. Then, where b is the distance from the center of the opening diameter a to the deepest portion of the micropores, the fineness having the opening diameter a of 0.5 μm or more and 10 μm or less and the distance b being 0.5 μm or more. When 100 or more holes were detected, it was confirmed that 60% or more of the holes had a distance b'of 0.5 μm or more. It should be noted that some examples of 100 or more fine pores existing at the boundary surface with the gold particle-containing thermosetting epoxy resin layer in the gold fine particle sintered body layer of the bonded body according to Examples 2 and 5 (here). Then, the values of a and b in a total of 3 cases) are shown in Table 3. Moreover, the morphology of the micropores shown in FIGS. 4 and 5 is shown.

As shown in Tables 2 and 3, the surface of an uncured gold particle-containing thermosetting epoxy resin molded body formed on a tungsten substrate with a dispersion containing gold fine particles in which an imine compound is retained on the surface. It was confirmed that in the bonded bodies according to Examples 1 to 6 obtained by applying the coating on the surface and performing heat treatment at a temperature of 300 ° C. or lower, a bonded body having high bonding strength that does not peel off even by the tape peeling test can be obtained. Was done. Further, as shown in Table 2, it was confirmed that the density of the gold fine particle sintered body layer of the bonded body according to Examples 1 to 6 was as high as 80% or more. Therefore, it was confirmed that a bonded body having good conductivity with low volume and low efficiency can be obtained.
As described above, according to the bonded body disclosed here, it is possible to provide a highly reliable bonded body including the metal fine particle sintered body layer and the resin layer.

Claims (14)

A bonded body of a metal layer made of a metal fine particle sintered body and a resin layer made of a resin.
At least a part of the metal layer is bonded to the resin layer.
A bonded body in which metal particles are contained in the resin layer, and at least a part of the internal metal particles is sintered with the metal fine particle sintered body. On the interface between the metal layer and the resin layer, micropores are present toward the inside of the resin layer.
The metal fine particle sintered body has entered at least a part of the micropores.
Here, the opening diameter of the micropores in the FE-SEM cross-sectional image showing the boundary surface is a, and the distance from the center of the opening diameter a to the deepest portion of the micropores in which the metal fine particle sintered body has penetrated. The bonded body according to claim 1, wherein when b'is used, the opening diameter a is 0.5 μm or more and 10 μm or less, and the distance b'is 0.5 μm or more. In the FE-SEM cross-sectional image showing the boundary surface, the opening diameter a is 0.5 μm or more and 10 μm or less and the distance from the center of the opening diameter a to the deepest part of the micropore is b. The bonded body according to claim 2, wherein when 100 or more of the micropores having a distance b of 0.5 μm or more are detected, 60% or more of the micropores have a distance b'of 0.5 μm or more. The bonded body according to any one of claims 1 to 3, wherein the main constituent metal element of the metal fine particles constituting the metal fine particle sintered body is a noble metal element. The bonded body according to any one of claims 1 to 3, wherein the main constituent metal element of the metal fine particles constituting the metal fine particle sintered body is gold (Au). The bonded body according to any one of claims 1 to 5, wherein the resin is a thermosetting resin as a component. The bonded body according to any one of claims 1 to 5, wherein the resin comprises a thermosetting epoxy resin as a component. The bonded body according to any one of claims 1 to 7, wherein the density of the metal layer is 80% or more. A method for producing a bonded body of a metal layer made of metal fine particles having an imine compound held on the surface and a resin layer made of a resin.
Prepare a dispersion containing the metal fine particles;
Applying the dispersion to the surface of a molded body made of the resin in an uncured state, where the molded body contains metal particles;
The metal layer is formed by heating the molded body coated with the dispersion in a temperature range in which the metal fine particles can be sintered; and the resin layer is formed by curing the molded body. To do;
A method for manufacturing a bonded body, including. The method for producing a bonded body according to claim 9, wherein the main constituent metal element of the metal fine particles is a noble metal element. The method for producing a bonded body according to claim 9, wherein the main constituent metal element of the metal fine particles is gold (Au). The method for producing a bonded body according to any one of claims 9 to 11, wherein the resin is a thermosetting resin as a component. The method for producing a bonded body according to any one of claims 9 to 11, wherein the resin comprises a thermosetting epoxy resin as a component. The imine compound has the following structural formula:
R ⁰ R ¹ C = N- (CH ₂ ) -R ²
The junction according to any one of claims 9 to 13, wherein R ⁰ is hydrogen and R ¹ and R ² are hydrocarbon groups having 3 to 7 carbon atoms, respectively. Body manufacturing method.

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