JP2016162919A - Bonding structure and manufacturing method of same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction in bonding strength even when being used for a long period of time under a high temperature environment.SOLUTION: A bonding structure (100) includes: a bonding target object (110); a bonding target object (120); and a bonding layer (130). The bonding layer (130) bonds the bonding target object (110) and the bonding target object (120). The bonding layer (130) contains metal particles (132) and suppression particles (134), for suppressing crystal growth of the metal particles (132).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bonded structure and a method for manufacturing the bonded structure.

  It is known that a plurality of members are joined together. For example, in a semiconductor device, a semiconductor chip is mounted on a substrate via a bonding layer. In recent years, it has been studied to mount a semiconductor element (particularly a power semiconductor element) often used in a high temperature environment on a substrate using a silver bonding layer obtained by sintering silver particles (see Patent Document 1). .

  Patent Document 1 discloses a bonding material containing, in addition to silver particles, a solvent, 2-butoxyethoxyacetic acid as a dispersant, and benzotriazole as a reaction inhibitor.

JP 2014-235842 A

  However, when a bonded structure manufactured using a conventional bonding material is used for a long time in a high temperature environment, the bonding strength of the bonding material may be significantly reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a bonded structure and a method for manufacturing the bonded structure that can suppress a decrease in bonding strength even when used under a high temperature environment for a long time. It is in.

  A joining structure according to the present invention includes a first joining object, a second joining object, and a joining layer that joins the first joining object and the second joining object. The bonding layer contains metal particles and suppressing particles that suppress crystal growth of the metal particles.

  In one embodiment, the metal particle has a porous structure.

  In one embodiment, the suppression particles include particles containing ceramics or an intermetallic compound.

  In one embodiment, the average particle size of the suppression particles is smaller than the average particle size of the metal particles.

  In one embodiment, the metal particles include silver particles.

  In one embodiment, the suppression particles include silicon carbide particles.

  In one embodiment, the ratio of the content of the suppression particles to the content of the metal particles is 0.05% by mass or more and 2.5% by mass or less.

  In one embodiment, the joining structure further includes a metal layer provided on a surface of at least one of the first joining object and the second joining object.

  In one embodiment, the metal layer contains the same metal as that constituting the metal particles.

  The method for manufacturing a bonded structure according to the present invention includes a step of preparing a first bonding target, a step of preparing a second bonding target, and a step of generating a particle-containing material obtained by adding metal particles and suppression particles to a medium. And a step of forming a laminated body in which the first joining object and the second joining object are laminated via the particle-containing material, and heating the laminated body, Forming a bonding layer for bonding the second object to be bonded from the particle-containing material.

  In one embodiment, the step of generating the particle-containing material includes a step of adding the metal particles and the suppression particles to a liquid to generate a solution, and evaporating the liquid from the solution to form the metal particles and the suppression. Extracting a powder of particles and mixing the powder with the medium to produce a paste.

  In one embodiment, in the step of producing the paste, the medium mixed with the powder is agitated.

  In a certain embodiment, the manufacturing method of the said joining structure further includes the process of forming a metal layer in the surface of at least one of the said 1st joining target object and the said 2nd joining target object.

  In one embodiment, in the step of forming the metal layer, the metal layer contains the same metal as that constituting the metal particles.

  ADVANTAGE OF THE INVENTION According to this invention, even if it uses a joining structure for a long time in a high temperature environment, the fall of the joint strength of a joining structure can be suppressed.

It is a schematic diagram of the junction structure by this embodiment. (A)-(e) is a schematic diagram which shows the manufacturing method of the joining structure body by this embodiment. It is a schematic diagram of the junction structure by this embodiment. (A)-(e) is a schematic diagram which shows the manufacturing method of the joining structure body by embodiment shown in FIG. (A)-(d) is a figure which shows the photograph of the sintered compact for a comparison. (A)-(d) is a figure which shows the photograph of the sintered compact corresponded to the joining layer contained in the joining structure body of an Example. (A) is a graph which shows the heating time change of the particle size increase amount of the metal particle in the sintered compact for a comparison, (b) is the sintered compact corresponding to the joining layer contained in the joining structure of an Example. It is a graph which shows the heating time change of the particle size increase amount of the metal particle in. It is a graph which shows the heating time change of the shear strength of the joining structure body of an Example and a comparative example. (A) is a graph which shows the SiC addition amount change of the shear strength of the joining structure of an Example and a comparative example, (b) is sintering corresponding to the joining layer contained in the joining structure of an Example and a comparative example. It is a graph which shows the SiC addition amount change of the resistivity in a body.

  Embodiments of a bonded structure and a method of manufacturing the bonded structure according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments.

  In FIG. 1, the schematic diagram of the joining structure 100 of this embodiment is shown. The bonded structure 100 includes a bonding target object 110, a bonding target object 120, and a bonding layer 130. The bonding layer 130 bonds the bonding target object 110 and the bonding target object 120. In the following description of the present specification, of the two joining objects 110 and 120, the joining object 110 may be described as a first joining object, and the joining object 120 is referred to as a second joining object. May be described.

  In the bonded structure 100 of the present embodiment, the bonding layer 130 contains metal particles 132 and suppressing particles 134. The suppression particles 134 suppress the crystal growth of the metal particles 132.

  Many of the metal particles 132 constitute aggregates having different sizes. Many of the aggregates of the metal particles 132 are in contact with other aggregates, and the metal particles 132 have a porous structure in which the particles themselves and the aggregates are connected in a network.

  The suppression particles 134 are dispersed in the metal particles 132. A part of the suppression particles 134 is present in a state separated from the other suppression particles 134 without aggregating with the other suppression particles 134. Further, another part of the suppression particles 134 constitutes aggregates having different sizes.

  The suppression particles 134 are present inside the aggregate of the metal particles 132. Typically, the suppression particles 134 are separated from each other and are hardly agglomerated. Such suppression particles 134 are present inside the aggregate of the metal particles 132.

  In addition, for example, when the bonding layer for bonding two objects to be bonded contains metal particles without containing inhibitor particles, even if a relatively high bonding strength can be realized temporarily, a high temperature environment (for example, When used at a temperature of 200 ° C. or higher for a long time, the metal particles may grow and grow in size, resulting in a significant decrease in bonding strength. Similarly, when such a bonded structure is used in a high temperature environment for a long time, the resistivity of the bonding layer may be greatly reduced.

  On the other hand, in the joining structure 100 of the present embodiment, the joining layer 130 containing the metal particles 132 can efficiently conduct the heat of one of the joining objects 110 and 120 to the other. In addition, the bonding layer 130 containing the metal particles 132 can efficiently pass a current from one contact object of the bonding objects 110 and 120 to the other contact object as necessary. Furthermore, in the bonded structure 100 of the present embodiment, the bonding layer 130 relieves thermal stress caused by the difference between the thermal expansion coefficient of the bonding target object 110 and the thermal expansion coefficient of the bonding target object 120.

  Furthermore, in the bonding structure 100 of the present embodiment, the bonding layer 130 contains not only the metal particles 132 but also the suppression particles 134, so even if the bonding structure 100 is used at a high temperature for a long time, The suppression particles 134 that suppress crystal growth suppress excessive enlargement of the metal particles 132, and as a result, a decrease in the bonding strength of the bonding layer 130 is suppressed.

  The joining object 110 may be an insulating member or a conductive member. Alternatively, the joining object 110 may be a semiconductor member.

  The bonding target 120 may be an insulating member or a conductive member. Alternatively, the bonding target 120 may be a semiconductor member.

  For example, the bonding target 110 may be an insulating substrate, and the bonding target 120 may be a semiconductor chip. As an example, the semiconductor chip is a power semiconductor chip containing SiC or GaN.

  The metal particles 132 preferably contain at least one selected from the group consisting of silver, copper, nickel, and zinc. In this case, the metal particles 132 preferably contain the metal as a main component. For example, the metal particle 132 preferably contains 50% by mass or more of the metal, more preferably 70% by mass or more, and still more preferably 900% by mass or more of the metal.

  Moreover, it is preferable that the metal particle 132 contains silver or copper among the said metal group, and in this case, the joining layer 130 can implement | achieve a higher electroconductivity characteristic and a high heat dissipation characteristic.

  The metal particles 132 further preferably contain silver. Silver atoms have a characteristic that a surface reaction occurs on the surface while reacting with oxygen in an environment of about 250 to 300 ° C. When silver having such characteristics is used as the metal particles 132, it is considered that the decrease in the bonding strength of the bonding layer 130 is suppressed by the interaction with the suppressing particles 134.

  The metal particles 132 may be spherical. In this case, the average particle size of the metal particles 132 is preferably 0.1 μm or more and 3 μm or less, and more preferably 0.2 μm or more and 2 μm or less.

  Alternatively, the metal particles 132 may be flaky. In this case, the average particle diameter of the metal particles 132 is preferably 2 μm or more and 15 μm or less, and more preferably 4 μm or more and 10 μm or less. In addition, the thickness of the metal particles 132 is preferably 50 nm or more and 600 nm or less, and more preferably 100 nm or more and 400 nm or less.

  The suppression particles 134 are preferably those that can be sufficiently dispersed in the metal particles 132. Moreover, it is preferable that the suppression particle 134 contains a component having relatively high thermal conductivity and electrical conductivity.

  For example, the suppression particles 134 include particles containing ceramics or an intermetallic compound. The ceramic of the suppression particles 134 preferably contains an inorganic compound such as an oxide, carbide, nitride, or boride, and particularly preferably contains a carbide or nitride. As an example, the suppression particles 134 preferably contain carbides such as Ti, Hf, and Cr, nitrides or borides, or oxides such as alumina and silica. In addition, silicon carbide particles are preferably used as the suppression particles 134. Alternatively, as the intermetallic compound of the suppression particles 134, for example, a tin-containing material including silver or nickel, or an aluminide-containing material including titanium or nickel is preferably used.

  The average particle size of the suppression particles 134 is preferably 10 nm or more and 3.0 μm or less, and more preferably 20 nm or more and 2.0 μm or less. In addition, the average particle size of the suppression particles 134 is preferably smaller than the average particle size of the metal particles 132. Here, the average particle diameter may be a median diameter. Alternatively, the average particle diameter may be a mode diameter or an arithmetic average diameter.

  In the bonding layer 130, the ratio of the content of the suppression particles 134 to the content of the metal particles 132 is preferably 0.05% by mass or more and 2.5% by mass or less, and 0.3% by mass or more and 2.0% or less. More preferably, it is at most mass%.

  In the bonded structure 100 of the present embodiment, the bonding between the bonding target object 110 and the bonding target object 120 can be maintained up to a temperature that reaches the melting point of the metal constituting the metal particles 132 in the bonding layer 130.

  Note that the bonding layer 130 may include micropores 136 in which neither the metal particles 132 nor the suppression particles 134 exist. In this case, the suppression particles 134 may be present in the micropore 136. However, in order to improve the bonding strength of the bonding layer 130, it is preferable to reduce the volume and number of micropores 136 per unit volume.

  Moreover, it is preferable that the metal exists in the form of a film on at least the surface of the first object 110 to be in contact with the bonding layer 130. Or it is preferable that the metal exists in the form of a film on at least the surface in contact with the bonding layer 130 of the second bonding object 120.

  Here, with reference to FIG. 2, the manufacturing method of the joining structure 100 of this embodiment is demonstrated.

  As shown in FIG. 2A, a bonding object 110 is prepared. The joining object 110 may be, for example, an insulating member or a conductive member. Alternatively, the bonding target object 110 may be a semiconductor member.

  As shown in FIG. 2B, a bonding target 120 is prepared. For example, the bonding target 120 may be an insulating member or a conductive member. Alternatively, the bonding target 120 may be a semiconductor member.

  As shown in FIG. 2C, a particle containing material S in which the metal particles 132 and the suppression particles 134 are added to the medium M is generated. The metal particles 132 are particles containing, for example, silver, copper, nickel, or zinc. The average particle diameter of the metal particles 132 is preferably 2 μm or more and 15 μm or less, and more preferably 4 μm or more and 10 μm or less.

  The suppression particles 134 are particles containing ceramics or an intermetallic compound. The average particle size of the suppression particles 134 is preferably 10 nm or more and 3.0 μm or less, and more preferably 20 nm or more and 2.0 μm or less.

  For example, the medium M is a solution or a paste. In this case, in the particle content S, it is preferable that the metal particles 132 and the suppression particles 134 are sufficiently dispersed in the medium M. For example, the metal particles 132 and the suppression particles 134 are preferably sufficiently stirred in the medium M or before being added to the medium M. In the medium M, the ratio of the content of the suppression particles 134 to the content of the metal particles 132 is preferably 0.05% by mass or more and 2.5% by mass or less, and 0.3% by mass or more and 2.0% by mass. More preferably, it is% or less.

  For example, the particle containing material S may be a paste. For example, the paste is generated as follows.

  First, the metal particles 132 and the suppression particles 134 are added to the liquid. For example, alcohol is used as the liquid, and ethanol is an example.

  Metal particles 132 and inhibitor particles 134 are added to the liquid to form a solution. The metal particles 132 and the suppression particles 134 may not be sufficiently dissolved in the solution, and the solution may be a suspension. Alternatively, the metal particles 132 and the suppression particles 134 may be sufficiently dissolved in the liquid.

  Next, the liquid is evaporated from the solution to extract the powder of the metal particles 132 and the suppression particles 134. Thereafter, the medium M is mixed with powder to produce a paste. For example, alcohol is used as the medium M. As an example, a suitable medium M includes ethylene glycol.

  In addition, when producing | generating a paste, it is preferable to fully stir the medium M with which the said powder was mixed. For example, stirring is preferably performed for 5 minutes to 2 hours.

  As shown in FIG. 2D, a laminated body L in which the first joining object 110 and the second joining object 120 are laminated through the particle containing material S is formed. For example, the laminated body L has the particle-containing material S attached to the surface of the first bonding object 110 and then the second bonding object 120 so as to face the first bonding object 110 through the particle-containing material S. May be arranged. Alternatively, the particle-containing material S may be attached to the surface of the second bonding target 120. Moreover, the laminated body L inject | pours the particle | grain containing material S between the 1st joining target object 110 and the 2nd joining target object 120 which were arrange | positioned so that a main surface may oppose at predetermined intervals beforehand. It may be formed.

  As shown in FIG. 2 (e), the layered product L is heated to form the bonding layer 130 for bonding the first bonding target 110 and the second bonding target 120 from the particle-containing material S. When the stacked body L is heated, the bonding layer 130 is sintered and the bonding layer 130 is formed.

  For example, the heating temperature is 150 ° C. or higher and 300 ° C. or lower, more preferably 200 ° C. or higher and 250 ° C. or lower. Typically, the heating temperature is higher than the boiling point of the medium M. The heating time is, for example, preferably from 10 minutes to 3 hours, more preferably from 20 minutes to 2 hours, and further preferably from 30 minutes to 1 hour.

  By heating, the medium M of the particle-containing material S is vaporized, and the metal particles 132 in the particle-containing material S form a porous structure. Thereby, the joining layer 130 which joins the 1st joining target object 110 and the 2nd joining target object 120 is formed.

  When the bonding layer 130 is formed, the stack L is heated when the stacked body L is heated so that the first bonding target 110 and the second bonding target 120 are bonded with sufficient strength via the bonding layer 130. Pressure may be applied to the body L. However, the laminate L may be heated without applying pressure to the laminate L.

  In addition, it is preferable that a film-form metal exists in the joining surface joined to the joining layer 130 in the first joining object 110. In addition, this metal is preferably the same as the metal constituting the metal particles 132 in the bonding layer 130.

  Moreover, it is preferable that a film-form metal exists in the joining surface joined to the joining layer 130 in the second joining object 120. In addition, this metal is preferably the same as the metal constituting the metal particles 132 in the bonding layer 130.

  Further, a metal layer may be separately formed between the bonding objects 110 and 120 and the bonding layer 130.

  Hereinafter, the bonded structure 100 of the present embodiment will be described with reference to FIG. FIG. 3 is a schematic view of the bonded structure 100 of the present embodiment.

  The bonding structure 100 illustrated in FIG. 3 includes a metal layer 142 between the bonding target object 110 and the bonding layer 130, and includes a metal layer 142 between the bonding target object 120 and the bonding layer 130. Except for this point, it has the same configuration as the bonded structure 100 described above with reference to FIG. Therefore, in order to avoid redundancy, some overlapping descriptions may be omitted.

  In the bonded structure 100 of the present embodiment, the metal layer 142 is provided between the bonding target object 110 and the bonding layer 130, and the metal layer 144 is provided between the bonding target object 120 and the bonding layer 130. Yes.

  The metal layer 142 preferably contains the same metal as the metal constituting the metal particles 132. In this case, even if the bonding target object 110 is formed of an arbitrary material, the bonding target object 110 can be suitably bonded to the bonding layer 130.

  The metal layer 144 preferably contains the same metal as that constituting the metal particles 132. In this case, even if the bonding target 120 is formed of an arbitrary material, the bonding target 120 can be suitably bonded to the bonding layer 130.

  In addition, when the metal constituting the metal layer in contact with the bonding layer is the same as the metal constituting the metal particles in the bonding layer, the metal particles in the bonding layer grow crystal if the bonding layer does not contain suppression particles. As a result, the metal in the metal layer diffuses into the bonding layer, and the strength of the metal layer may decrease.

  On the other hand, in the bonding structure 100 of the present embodiment, the bonding layer 130 contains the suppression particles 134 together with the metal particles 132, so that crystal growth and enlargement of the metal particles 132 in the bonding layer 130 can be suppressed. . Therefore, diffusion of the metal from the metal layers 142 and 144 toward the bonding layer 130 can be suppressed, and as a result, a decrease in strength of the metal layers 142 and 144 can be suppressed.

  Note that the metal layer 142 may have a stacked structure. For example, the metal layer 142 may include a base film that is in direct contact with the main surface of the first object 110 and a conductive film that covers the base film. For example, the base film contains nickel and / or palladium. In addition, the conductive film contains the same metal as the metal that forms the metal particles 132 in the bonding layer 130.

  Similarly, the metal layer 144 may have a stacked structure. For example, the metal layer 142 may include a base film that is in direct contact with the main surface of the first object 110 and a conductive film that covers the base film. For example, the base film contains nickel and / or palladium. In addition, the conductive film contains the same metal as the metal that forms the metal particles 132 in the bonding layer 130.

  As described above, since the metal layer 142 exists between the first object 110 and the bonding layer 130 and the metal layer 144 exists between the second object 120 and the bonding layer 130, the bonding layer 130 and the metal layers 142 and 144 are bonded more strongly, and the bonding strength of the bonded structure 100 can be increased.

  In addition, as a material of the bonding target object 110 and the metal layer 142, a material is selected in which the thermal expansion coefficient of the metal layer 142 is larger than the thermal expansion coefficient of the bonding target object 110 and the difference between the two is larger. As a result, stress migration may be generated in the metal layer 142 to realize bonding between the bonding layer 130 and the metal layer 142. Stress migration is a material that has a high coefficient of thermal expansion as a result of a stress gradient generated in the material due to the difference in thermal expansion caused by the temperature change when the temperature changes while materials with different coefficients of thermal expansion are in contact with each other. This is a phenomenon in which these elements move.

  The bonded structure 100 according to the present embodiment can realize good bonding by intentionally using such stress migration. Specifically, when the temperature is changed while two kinds of materials having a large difference in thermal expansion coefficient are in contact with each other, a stress gradient is generated in the metal layer 142. This gradient causes stress migration, and the metal of the metal layer 142 diffuses so as to overflow from the surface. When the metal of the metal layer 142 is diffused, the metal is integrated by filling the voids of the unevenness at the interface between the bonding layer 130 and the metal layer 142 or the interface inside the metal layer 142. And the bonding layer 130 are bonded satisfactorily. Note that the occurrence of stress migration can be confirmed by photographing the junction cross section using an apparatus such as a scanning electron microscope (SEM). Further, in the formation of the bonding portion, the growth of the bonding necking can be promoted by forming nanoparticles or an amorphous nanostructure by a surface reaction in the bonding atmosphere.

  Note that, similarly to the metal layer 142, stress migration may be generated in the metal layer 144 to realize bonding between the bonding layer 130 and the metal layer 144.

  The joint structure 100 shown in FIG. 3 can be manufactured as follows. Hereinafter, with reference to FIG. 4, the manufacturing method of the joining structure 100 of this embodiment is demonstrated.

  As shown in FIG. 4A, a bonding object 110 provided with a metal layer 142 on the main surface is prepared. For example, the joining object 110 may be prepared, and the metal layer 142 may be formed on the main surface of the joining object 110. As an example, the metal layer 142 is formed by a plating process. Alternatively, the metal layer 142 may be formed by sputtering.

  As shown in FIG. 4B, a bonding target 120 having a metal layer 144 provided on the main surface is prepared. For example, the joining target 120 is prepared, and the metal layer 144 is formed on the main surface of the joining target 120. As an example, the metal layer 144 is formed by a plating process. Alternatively, the metal layer 144 may be formed by sputtering.

  As shown in FIG. 4C, a particle containing material S in which the metal particles 132 and the suppression particles 134 are added to the medium M is generated. The metal particles 132 are particles containing, for example, silver, copper, nickel, or zinc. The suppression particles 134 are particles containing ceramics or an intermetallic compound.

  As illustrated in FIG. 4D, a stacked body L in which the first bonding target object 110 and the second bonding target object 120 are stacked is formed via the particle-containing material S. For example, the laminated body L has the particle-containing material S attached to the surface of the first bonding object 110 and then the second bonding object 120 so as to face the first bonding object 110 through the particle-containing material S. May be arranged. Or the laminated body L inject | pours the particle | grain content S between the 1st joining target object 110 and the 2nd joining target object 120 which were arrange | positioned so that it may leave | separate a predetermined space | interval previously, and a main surface may oppose. Good.

  As shown in FIG. 4 (e), the laminated body L is heated to form the bonding layer 130 for bonding the first bonding target 110 and the second bonding target 120 from the particle-containing material S. For example, the heating temperature is 150 ° C. or higher and 300 ° C. or lower, more preferably 200 ° C. or higher and 250 ° C. or lower.

  In the above description with reference to FIG. 3 and FIG. 4, the metal layers 142 and 144 are provided on the two opposing main surfaces of the first joining object 110 and the second joining object 120, and the first joining is performed. Although the object 110 and the second bonding object 120 are bonded via the metal layer 142, the bonding layer 130, and the metal layer 144, the present invention is not limited to this. One of the two main surfaces of the first joining object 110 and the second joining object 120 facing each other is provided with one of the metal layers 142 and 144, and the first joining object 110 and the second joining object. The object 120 may be bonded through the bonding layer 130 and the metal layer 142 or the metal layer 144.

[Change in structure of metal particles with heating time]
The change in the structure of the metal particles with heating time was measured as follows.

(Preparation of particle-containing material a)
100 ml of 100 parts by mass of flaky silver particles (manufactured by Fukuda Metal Foil Powder Co., Ltd., product name “AgC-239”) and 2 parts by mass of SiC particles (manufactured by Superior Graphite, product name “HSC059”) Was partially dissolved in ethanol solution. The silver particles had a median diameter of 6.0 μm and a thickness of 260 mm, and a specific surface area of 5.0 m ² / g. The SiC particles had a polygonal shape with a median diameter of 0.6 μm. The resulting suspension was stirred for 10 minutes and sonicated for 30 minutes.

  Then, by leaving it at 50 ° C. for 5 hours, the ethanol solution was sufficiently evaporated from the suspension and dried to take out the powder. This powder was mixed with ethylene glycol and stirred for 10 minutes to produce a paste. The viscosity of the paste was 300 ± 100 Pa · S. As described above, a paste-like particle-containing material a was produced.

(Preparation of sintered body a)
The particle-containing material a was applied to a glass substrate having a length of 76 mm and a width of 26 mm so as to form a sheet having a length of 76 mm, a width of 3 mm, and a thickness of 0.04 mm. Thereafter, the particle-containing material a was heated on the hot plate in the atmosphere at 250 ° C. for 30 minutes to sinter the particle-containing material a, and then the temperature was lowered to room temperature to produce a plurality of sintered bodies a. Needless to say, the sintered body a corresponds to the bonding layer of the bonding structure of the example.

(Imaging)
One sintered body a was imaged using a field emission scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, product name “SU8200”). Further, another sintered body a was heated at 250 ° C. for 50 hours, 100 hours, and 200 hours, respectively, and imaged in the same manner. In addition, the heating temperature of another sintered body a was changed from 250 ° C. to 200 ° C. and heated for 50 hours, 100 hours, and 200 hours, respectively. Further, the heating temperature of another sintered body a was changed from 250 ° C. to 150 ° C. and heated for 50 hours, 100 hours, and 200 hours, respectively.

  For comparison, a paste-like particle-containing material h was prepared in the same manner as the particle-containing material a, except that no SiC particles were added to the ethanol solution. Further, a plurality of sintered bodies h were produced from the particle-containing material h similarly to the sintered body a, and the sintered body h was imaged in the same manner as the sintered body a. Further, another sintered body h was heated at 250 ° C. for 50 hours, 100 hours, and 200 hours, respectively, and imaged in the same manner.

  FIGS. 5A to 5D are photographs showing a sintered body h for comparison. FIG. 5A is a view showing a photograph of the sintered body h that was not heated, and FIG. 5B is a view showing a photograph of the sintered body h that was heated for 50 hours, and FIG. ) Is a view showing a photograph of the sintered body h heated for 100 hours, and FIG. 5D is a view showing a photograph of the sintered body h heated for 200 hours.

  As is apparent from FIGS. 5A to 5D, when the sintered body h does not contain the suppression particles, the particle size of the silver particles in the sintered body h increases as the heating time increases.

  FIG. 6A to FIG. 6D are photographs showing a sintered body corresponding to the bonding layer in the bonding structure of the example. 6A is a view showing a photograph of the sintered body a before heating, and FIG. 6B is a view showing a photograph of the sintered body a after being heated for 50 hours. (c) is a figure which shows the photograph of the sintered compact a after heating for 100 hours, FIG.6 (d) is a figure which shows the photograph of the sintered compact a after heating for 200 hours.

  As apparent from FIGS. 6A to 6D, when the sintered body a contains SiC particles together with the silver particles, the particles of the silver particles in the sintered body a even if the heating time is increased. The diameter hardly changed.

  FIG. 7A is a graph showing changes in heating time of the average increase in the average particle diameter of silver particles in a sintered body h for comparison. In addition, the particle diameter increase amount of silver particle was calculated | required by comparing the particle diameter of the imaged silver particle with the average particle diameter of the silver particle added at the time of preparation of the particle content h.

  In the graph of FIG. 7A, a line T1 indicates a change in the heating time of the particle size increase amount of the silver particles when the heating temperature is 150 ° C., and a line T2 indicates the silver particles when the heating temperature is 200 ° C. A change in the heating time of the particle size increase amount is shown, and a line T3 shows a change in the heating time of the particle size increase amount of the silver particles when the heating temperature is 250 ° C.

  As understood from the graph of FIG. 7A, when the heating temperature was 150 ° C. and 200 ° C., the increase in the particle size hardly changed even when the heating time was changed. On the other hand, when the heating temperature was 250 ° C., the amount of increase in the particle size significantly increased as the heating time increased.

  FIG.7 (b) is a graph which shows the heating time change of the average particle diameter increase amount of the silver particle in the sintered compact corresponding to the joining layer in the joining structure of an Example. In addition, the particle diameter increase amount of silver particle was calculated | required by comparing the particle diameter of the imaged silver particle with the average particle diameter of the silver particle added at the time of preparation of the particle containing material a.

  In the graph of FIG. 7B, the line T1 shows the change in the heating time of the increase in the particle size of the silver particles when the heating temperature is 150 ° C., and the line T2 shows the silver particles when the heating temperature is 200 ° C. A change in the heating time of the particle size increase amount is shown, and a line T3 shows a change in the heating time of the particle size increase amount of the silver particles when the heating temperature is 250 ° C.

  As can be seen from the graph of FIG. 7B, the increase in the particle size hardly changed despite the increase in the heating time, regardless of whether the heating temperature was 150 ° C., 200 ° C., or 250 ° C. .

[Measurement of shear strength of bonded structure]
The shear strength of the bonded structure was measured as follows.

(Preparation of bonded structure a)
An electroless Ni / Ag plating process is performed on the surface of a copper plate having a thickness of 0.8 mm, and then a substrate having a length of 30 mm, a width of 30 mm and a thickness of 0.8 mm, a length of 3 mm, a width of 3 mm and a thickness of the copper plate. A 0.8 mm chip was taken out. Next, the particle-containing material a was applied to the surface of the substrate, and a laminate in which a chip was mounted on the particle-containing material a was produced. Thereafter, a pressure of about 0.4 MPa was applied to the laminate using a steel weight, and the laminate was heated on the hot plate in the atmosphere at 250 ° C. for 30 minutes. As described above, a plurality of bonded structures a of the example were manufactured.

(Preparation of joined structure a1)
A particle-containing material a1 was produced in the same manner as the particle-containing material a except that the addition amount of SiC particles was changed from 2 parts by mass to 0.3 parts by mass. Except for changing the particle-containing material a to the particle-containing material a1, a plurality of bonded structures a1 of Examples were produced in the same manner as the bonded structure a.

(Preparation of joined structure a2)
A particle-containing material a2 was produced in the same manner as the particle-containing material a except that the addition amount of SiC particles was changed from 2 parts by mass to 5 parts by mass. Except for changing the particle-containing material a to the particle-containing material a2, a plurality of bonded structures a2 of Examples were produced in the same manner as the bonded structure a.

(Preparation of bonded structure h)
Except for changing the particle-containing material a to the particle-containing material h, a plurality of bonded structures h of comparative examples were produced in the same manner as the bonded structure a.

(Shear test)
A shear test was performed on the bonded structure a using a shear tester (Dage, product name “XD-7500”). The shear test was performed on at least five samples prepared in the same manner, and an average of them was obtained.

  Further, another joint structure a was heated at 250 ° C. for 50 hours, and a shear test was performed in the same manner. Further, another bonded structure a was heated at 250 ° C. for 100 hours, and a shear test was performed in the same manner. Further, another bonded structure a was heated at 250 ° C. for 200 hours, and a shear test was performed in the same manner.

  A shear test was also performed on the bonded structure a1. Further, the bonded structure a1 was heated at 250 ° C. for 50 hours, 100 hours, and 200 hours, respectively, and a shear test was similarly performed.

  Further, a shear test was performed on the bonded structure a2. Further, the joining structure a2 was heated at 250 ° C. for 50 hours, 100 hours, and 200 hours, respectively, and a shear test was similarly performed.

  A shear test was also performed on the bonded structure h. Further, the bonded structure h was heated at 250 ° C. for 50 hours, 100 hours, and 200 hours, respectively, and a shear test was performed in the same manner.

  FIG. 8 is a graph showing the heating time change of the shear strength of the joining structures a, a1, a2 of the example and the joining structure h of the comparative example. In the graph of FIG. 8, a line C indicates a change in the heating time of the shear strength of the bonded structure h, a line S1 indicates a change in the heat strength of the bonded structure a, and a line S2 indicates the bonded structure a1. A change in the shearing time of the heating strength is shown, and a line S3 shows a change in the heating time of the shearing strength of the bonded structure a2.

  As apparent from the line C in FIG. 8, in the bonded structure h, the bonding layer contained metal particles, but did not contain suppression particles, so that the shear strength was greatly reduced as the heating time was increased. On the other hand, as is clear from the lines S1, S2, and S3 in FIG. 8, in the bonding structures a, a1, and a2, the bonding layer contains metal particles and suppression particles, so that the heating time increases. The decrease in shear strength was suppressed. In particular, in the bonded structure a, the shear strength once decreased when the heating time was 50 hours, but when the heating time was further increased, the shear strength increased and a relatively high shear strength could be maintained.

[Measurement of shear strength according to the amount of SiC particles added]
The shear strength was measured according to the amount of SiC particles added as follows.

(Preparation of bonded structure a3)
Except for changing the heating time at the time of manufacturing the bonded structure from 30 minutes to 60 minutes, the bonded structure a3 of the example was manufactured in the same manner as the bonded structure a.

(Preparation of bonded structure a4)
Except having changed the addition amount of SiC particle | grains from 2 mass parts to 1 mass part, the junction structure a4 of the Example was produced similarly to the junction structure a3.

(Preparation of bonded structure a5)
Except having changed the addition amount of SiC particle from 2 mass parts to 0.3 mass part, the junction structure a5 of the Example was produced similarly to the junction structure a3.

(Preparation of joined structure a6)
Except having changed the addition amount of SiC particle from 2 mass parts to 0.1 mass part, the junction structure a6 of the Example was produced similarly to the junction structure a3.

(Preparation of bonded structure b3)
Except for changing the type of the SiC particles from the product name “HSC059” to the product name “HSC007” (manufactured by Superior Graphite, Inc .: polygonal shape with a median diameter of 1.3 μm), the junction structure of the example is similar to the junction structure a3. b3 was produced.

(Preparation of bonded structure b4)
Except for changing the addition amount of SiC particles from 2 parts by mass to 1 part by mass, the junction structure b4 of the example was produced in the same manner as the junction structure b3.

(Preparation of bonded structure b5)
Except having changed the addition amount of SiC particle from 2 mass parts to 0.3 mass part, the junction structure b5 of the Example was produced similarly to the junction structure b3.

(Preparation of bonded structure b6)
Except having changed the addition amount of SiC particle from 2 mass parts to 0.1 mass part, the junction structure b6 of the Example was produced similarly to the junction structure b3.

(Preparation of joined structure c3)
Except for changing the type of SiC particles from the product name “HSC059” to the product name “SiC-35” (CEA (manufactured by the French Atomic Energy and Alternative Energy Agency): spherical with a median diameter of 0.035 μm), the same as the bonded structure a3 The junction structure c3 of Example was prepared.

(Preparation of bonded structure c4)
Except for changing the addition amount of SiC particles from 2 parts by mass to 1 part by mass, the junction structure c4 of the example was produced in the same manner as the junction structure c3.

(Preparation of bonded structure c5)
Except having changed the addition amount of SiC particle from 2 mass parts to 0.3 mass part, the junction structure c5 of the Example was produced similarly to the junction structure c3.

(Preparation of bonded structure c6)
Except having changed the addition amount of SiC particle from 2 mass parts to 0.1 mass part, the junction structure c6 of the Example was produced similarly to the junction structure c3.

(Preparation of bonded structure h1)
A bonded structure h1 of a comparative example was produced in the same manner as the bonded structure h except that the heating time was changed from 30 minutes to 60 minutes.

(Shear test)
A shear test was performed on the bonded structures a3 to a6, b3 to b6, c3 to c6, and h1 using a shear tester (Dage, product name “XD-7500”). The shear test was performed on at least 5 samples prepared in the same manner, and the average of the results was obtained.

  FIG. 9A is a graph showing changes in the amount of SiC added to the shear strength of the joined structures a3 to a6, b3 to b6, c3 to c6, and h1. In the graph of FIG. 9A, the point C indicates the shear strength of the bonded structure h1, the line S1 indicates a change in the amount of SiC added to the shear strength of the bonded structures a3 to a6, and the line S2 indicates the bonded structure. The change in the SiC addition amount of the shear strength of the joined structures of the bodies b3 to b6 is shown, and the line S3 shows the change of the SiC addition amount of the shear strength of the joined structures c3 to c6.

  As is clear from the point C in FIG. 9A, in the bonding structure h1, the bonding layer contains metal particles. However, when the bonding layer does not contain suppression particles, the bonding structure h1 has a relatively high shear. Had strength. On the other hand, as is clear from the lines S1, S2, and S3 in FIG. 9A, in the bonded structures a3 to a6, b3 to b6, and c3 to c6, the bonding structure increases when the SiC addition amount increases. The shear strength of tended to decrease slightly.

  Specifically, when the particle diameter of the SiC particles is 0.6 μm and 1.3 μm, the shear strength of the bonded structure did not change much regardless of the change in the addition amount of the SiC particles. On the other hand, when the particle size of the SiC particles was 0.035 μm, the shear strength was greatly reduced as the amount of SiC particles added increased. This is presumably because the SiC particles having a small particle diameter were not sufficiently dispersed although they were stirred, and as a result, the enlargement of the silver particles could not be suppressed.

[Measurement of resistivity according to the amount of SiC particles added]
The resistivity was measured according to the amount of SiC particles added as follows.

(Preparation of sintered body a3)
A sintered body a3 was produced in the same manner as the sintered body a, except that the heating time for producing the sintered body was changed from 30 minutes to 60 minutes.

(Preparation of sintered body a4)
A sintered body a4 was produced in the same manner as the sintered body a3 except that the addition amount of SiC particles was changed from 2 parts by mass to 1 part by mass.

(Preparation of sintered body a5)
A sintered body a5 was produced in the same manner as the sintered body a3 except that the addition amount of SiC particles was changed from 2 parts by mass to 0.3 parts by mass.

(Preparation of sintered body a6)
A sintered body a6 was produced in the same manner as the sintered body a3 except that the addition amount of SiC particles was changed from 2 parts by mass to 0.1 parts by mass.

(Preparation of sintered body a7)
A sintered body a7 was produced in the same manner as the sintered body a3 except that the addition amount of SiC particles was changed from 2 parts by mass to 5 parts by mass.

(Preparation of sintered body b3)
Except for changing the type of SiC particles from the product name “HSC059” to the product name “HSC007” (supplied by Superior Graphite: polygon shape with median diameter of 1.3 μm: specific surface area 14-18.5), the sintered body a3 and Similarly, a sintered body b3 was produced.

(Preparation of sintered body b4)
A sintered body b4 was produced in the same manner as the sintered body b3 except that the addition amount of SiC particles was changed from 2 parts by mass to 1 part by mass.

(Preparation of sintered body b5)
A sintered body b5 was produced in the same manner as the sintered body b3 except that the addition amount of SiC particles was changed from 2 parts by mass to 0.3 parts by mass.

(Preparation of sintered body b6)
A sintered body b6 was produced in the same manner as the sintered body b3 except that the addition amount of SiC particles was changed from 2 parts by mass to 0.1 parts by mass.

(Preparation of sintered body b7)
A sintered body b7 was produced in the same manner as the sintered body b3 except that the addition amount of SiC particles was changed from 2 parts by mass to 5 parts by mass.

(Preparation of sintered body c3)
Same as sintered body a3, except that the type of SiC particles is changed from the product name “HSC059” to the product name “SiC-35” (CEA (manufactured by the French Nuclear and Alternative Energy Agency): spherical with a median diameter of 0.035 μm). A sintered body c3 was prepared.

(Preparation of sintered body c4)
A sintered body c4 was produced in the same manner as the sintered body c3 except that the addition amount of SiC particles was changed from 2 parts by mass to 1 part by mass.

(Preparation of sintered body c5)
A sintered body c5 was produced in the same manner as the sintered body c3 except that the addition amount of SiC particles was changed from 2 parts by mass to 0.3 parts by mass.

(Preparation of sintered body c6)
A sintered body c6 was produced in the same manner as the sintered body c3 except that the addition amount of SiC particles was changed from 2 parts by mass to 0.1 parts by mass.

(Preparation of sintered body c7)
A sintered body c7 was produced in the same manner as the sintered body c3 except that the addition amount of SiC particles was changed from 2 parts by mass to 5 parts by mass.

(Preparation of sintered body h1)
A sintered body h1 for comparison was produced in the same manner as the sintered body h, except that the heating time was changed from 30 minutes to 60 minutes.

(Measurement of electrical resistivity)
The resistivity of each of the sintered bodies a3 to a7, b3 to b7, c3 to c7, and h1 was measured using a resistivity meter (product name “Loresta-GP” manufactured by Mitsubishi Analytech Co., Ltd.).

  FIG. 9B is a graph showing changes in the amount of SiC added to the resistivity of the sintered bodies a3 to a6, b3 to b6, c3 to c6, and h1. In the graph of FIG. 9B, the point C indicates the resistivity of the sintered body h1, the line S1 indicates a change in the amount of SiC added to the resistivity of the sintered bodies a3 to a7, and the line S2 indicates the sintered body. The SiC addition amount change of the resistivity of the bodies b3 to b7 is shown, and the line S3 shows the SiC addition amount change of the resistivity of the sintered bodies c3 to c7.

  As is clear from the point C in FIG. 9B, in the sintered body h1, the bonding layer contained metal particles, but did not contain suppression particles. The sintered body h1 exhibited a relatively low resistivity. On the other hand, in the sintered bodies a3 to a7, b3 to b7, and c3 to c7, as is clear from the lines S1, S2, and S3 in FIG. The shear strength of tended to increase slightly.

  Specifically, when the particle diameter of the SiC particles is 0.6 μm and 1.3 μm, the resistivity of the sintered body hardly changed even when the addition amount of the SiC particles was increased. On the other hand, when the particle size of the SiC particles was 0.035 μm, the resistivity of the sintered body significantly increased as the amount of SiC particles added increased. This is presumably because the SiC particles having a small particle diameter were not sufficiently dispersed by simply stirring, and as a result, the enlargement of the silver particles could not be suppressed.

  According to the present invention, even when exposed to a high temperature environment for a long time, a decrease in bonding strength is suppressed.

DESCRIPTION OF SYMBOLS 100 Joining structure 110 1st joining object 120 2nd joining object 130 Joining layer 132 Metal particle 134 Suppression particle 136 Micropore

Claims (14)

A first object to be joined;
A second object to be joined;
A bonding structure comprising a bonding layer for bonding the first bonding object and the second bonding object,
The bonding layer is a bonded structure including metal particles and suppressing particles that suppress crystal growth of the metal particles.   The bonded structure according to claim 1, wherein the metal particles have a porous structure.   The bonded structure according to claim 1, wherein the suppressing particles include particles containing ceramics or an intermetallic compound.   The bonded structure according to any one of claims 1 to 3, wherein an average particle diameter of the suppression particles is smaller than an average particle diameter of the metal particles.   The bonded structure according to claim 1, wherein the metal particles include silver particles.   The bonded structure according to claim 1, wherein the suppression particles include silicon carbide particles.   In the said joining layer, the ratio of content of the said suppression particle with respect to content of the said metal particle is 0.05 mass% or more and 2.5 mass% or less, The joining structure in any one of Claim 1 to 6 .   The joining structure according to any one of claims 1 to 7, further comprising a metal layer provided on at least one surface of the first joining object and the second joining object.   The bonded structure according to claim 8, wherein the metal layer includes the same metal as that of the metal particles. Preparing a first object to be joined;
Preparing a second joining object;
Producing a particle-containing material obtained by adding metal particles and inhibitor particles to a medium;
Forming a laminate in which the first joining object and the second joining object are laminated via the particle-containing material;
The manufacturing method of a joining structure including the process of forming the joining layer which joins the 1st joined object and the 2nd joined object from the particle content by heating the layered product. The step of generating the particle-containing material includes:
Adding the metal particles and the suppression particles to a liquid to form a solution;
Evaporating the liquid from the solution to extract powders of the metal particles and the suppression particles;
The manufacturing method of the joining structure of Claim 10 including the process of mixing the said powder with the said medium and producing | generating a paste.   The method for manufacturing a joined structure according to claim 11, wherein the medium mixed with the powder is stirred in the step of generating the paste.   The method for manufacturing a joined structure according to any one of claims 10 to 12, further comprising a step of forming a metal layer on at least one surface of the first joining object and the second joining object. .   The method for manufacturing a bonded structure according to claim 13, wherein in the step of forming the metal layer, the metal layer includes the same metal as that of the metal particles.