JP6898509B1 - Joint layer structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding layer structure portion capable of maintaining excellent bonding strength and mechanical strength even with severe temperature fluctuations in an extremely high temperature or extremely low temperature environment. SOLUTION: The joint layer structure portion constitutes a joint portion of an electric and electronic device, and the joint layer structure portion contains Sn, Cu, Ni and Ge in a matrix containing Sn and Sn—Cu alloy. The above problem was solved by the bonding layer structure having an intermetallic compound. [Selection diagram] FIG. 9

Description

The present invention relates to a junction layer structure.

With the progress of IoT (Internet of Things) and the demand for further energy saving, the importance of power semiconductors, which play a central role in the technology, is increasing. However, there are many problems in its utilization. Since a power semiconductor handles a large amount of electric power having a high voltage and a large current, it generates a lot of heat and becomes a high temperature. The heat resistance required for current Si power semiconductors is about 175 ° C, but the development of Si power semiconductors that can withstand temperatures of about 200 ° C is underway, and next-generation products such as SiC and GaN are being developed. Power semiconductors are required to withstand 250 to 500 ° C.

On the other hand, regarding the bonding material, there is no bonding material having high heat resistance required for next-generation power semiconductors such as SiC and GaN as described above.
For example, the SnAgCu-based bonding material (powdered solder material) disclosed in Patent Document 1 can only be applied to a power semiconductor corresponding to about 125 ° C., and cannot be applied to a next-generation power semiconductor. ..

On the other hand, in Patent Document 2, the applicant comprises an outer shell and a core portion, the core portion contains a metal or an alloy, and the outer shell is composed of a network of intermetallic compounds, and the core portion is formed. It covers, the core portion contains Sn or Sn alloy, and the outer shell proposes metal particles containing an intermetallic compound of Sn and Cu. The joint formed by these metal particles is used in a harsh environment such that even if the high temperature operation state continues for a long time or the temperature fluctuates greatly from the high temperature operation state to the low temperature stop state. However, high heat resistance, bonding strength and mechanical strength can be maintained for a long period of time.
However, the intermetallic compound has a weakness of being brittle, and if this problem is solved, it is possible to provide a joint layer structure portion having higher heat resistance, joint strength and mechanical strength.

JP-A-2007-268569 Japanese Patent No. 60292222

An object of the present invention is to provide a joint layer structure portion capable of maintaining excellent joint strength and mechanical strength even with severe temperature fluctuations in an extremely high temperature or extremely low temperature environment.

As a result of diligent studies, the present inventor has found that the above-mentioned problems can be solved in a metal by using metal particles having a specific metal compound in a specific matrix, and have completed the present invention.
That is, the present invention is a joint layer structure portion constituting a joint portion of an electric and electronic device, and the joint layer structure portion contains Sn, Cu, Ni and Ge in a matrix containing Sn and Sn—Cu alloy. It provides a junction layer structure having an intermetallic compound containing.

According to the present invention, it is possible to provide a joint layer structure portion capable of maintaining excellent joint strength and mechanical strength even with severe temperature fluctuations in an extremely high temperature or extremely low temperature environment. As a joint portion of an electric / electronic device, the above effect can be obtained even if one adherend and the other adherend are materials having different coefficients of thermal expansion (for example, Si and Cu).

It is a STEM image of the cross section which thinly cut the metal particle of this invention with FIB (focused ion beam). It is a figure for demonstrating an example of the manufacturing apparatus suitable for manufacturing the metal particle of this invention. It is the element mapping analysis result by EDS of the metal particle cross section shown in FIG. It is a STEM image and a partial analysis result of the cross section of a metal particle obtained in Example 1. It is an optical microscope image of the cross section of the bonding layer structure part after bonding a copper substrate and a silicon element with the bonding material containing metal particles obtained in Example 1 and subjecting them to a thermal shock test. It is the STEM image of the cross section of the conventional SnAgCu-based bonding material and the element mapping analysis result by EDS. It is an optical microscope image of the cross section of the bonding layer structure part after bonding a copper substrate and a silicon element with the bonding material obtained in Comparative Example 1 and subjecting it to a thermal shock test. It is a schematic cross-sectional view for demonstrating the structure of the joint layer structure part of this invention. TEM image showing the interface between the intermetallic compound crystal and the matrix in the cross section of the junction layer structure obtained in Example 1, and the transmission electron diffraction pattern of the interface between the matrix and the intermetallic compound crystal. It is a cross-sectional SEM photograph which shows the joint layer structure part after removing the single Sn alloy from the bond layer structure part formed in Example 1. FIG.

Hereinafter, the present invention will be described in more detail.
First, the terminology used herein is as follows, even if not specifically explained.
(1) The term metal may include not only a simple substance of a metal element but also an alloy containing a plurality of metal elements and an intermetallic compound.
(2) When referring to a single metal element, it does not mean only a substance completely purely composed of the metal element, but also means a case containing a slight other substance. That is, it does not mean to exclude those containing a trace amount of impurities that have almost no effect on the properties of the metal element. Of course, in the case of a matrix, for example, some of the atoms in the Sn crystal are other elements ( For example, it does not mean to exclude those that have been replaced with Cu). For example, the other substance or other element such as Al, Co, Fe, Mn, Mo, Cr may be contained in the metal particles in an amount of 0 to 1% by mass.
(3) Endotactic bonding means that an intermetallic compound is deposited in a substance that becomes a metal / alloy (in the present invention, a matrix phase containing Sn and a Sn—Cu alloy), and during this precipitation, a Sn—Cu alloy is formed. It means that the intermetallic compound is bonded at the crystal lattice level to form crystal grains. The term endotactic is well known and is described, for example, in Nature Chemisry 3 (2): 160-6, 2011, page 160, left column, final paragraph.

The joint layer structure portion of the present invention can be formed by using the following metal particles (hereinafter, may be referred to as the metal particles of the present invention).

FIG. 1 is an STEM image of a cross section obtained by thinly cutting the metal particles of the present invention with a FIB (focused ion beam). The particle size of the metal particles shown in FIG. 1 is about 5 μm, but the particle size of the metal particles of the present invention is preferably in the range of, for example, 1 μm to 50 μm. Referring to the metal particles of FIG. 1, the metal particles have an intermetallic compound 120 containing Sn, Cu, Ni and Ge in a matrix 140 containing a Sn and Sn—Cu alloy.

The metal particles of the present invention contain, for example, 0.7 to 15% by mass of Cu, 0.1 to 5% by mass of Ni, 0.001 to 0.1% by mass of Ge, and Sn in the balance, preferably Cu. Is 1 to 15% by mass, Ni is 0.1 to 3% by mass, Ge is 0.001 to 0.01% by mass, and the balance is Sn.

The metal particles of the present invention can be produced from, for example, a raw material having a composition of 8% by mass Cu, 1% by mass Ni, 0.001% by mass Ge and the balance Sn. For example, it is obtained by melting the current raw material, supplying it onto a dish-shaped disk that rotates at high speed in a nitrogen gas atmosphere, scattering the molten metal as small droplets by centrifugal force, and cooling and solidifying under reduced pressure. ..

An example of a manufacturing apparatus suitable for manufacturing the metal particles of the present invention will be described with reference to FIG. The granulation chamber 1 has a cylindrical upper portion and a cone-shaped lower portion, and has a lid 2 at the upper portion. A nozzle 3 is vertically inserted into the center of the lid 2, and a dish-shaped rotating disc 4 is provided directly below the nozzle 3. Reference numeral 5 is a mechanism for supporting the dish-shaped rotating disc 4 so as to be movable up and down. Further, a discharge pipe 6 for the generated particles is connected to the lower end of the cone portion of the granulation chamber 1. The upper part of the nozzle 3 is connected to an electric furnace (high frequency furnace) 7 that melts the metal to be granulated. Atmospheric gas adjusted to a predetermined component in the mixed gas tank 8 is supplied to the inside of the granulation chamber 1 and the upper part of the electric furnace 7 by the pipes 9 and 10, respectively. The pressure in the granulation chamber 1 is controlled by the valve 11 and the exhaust device 12, and the pressure in the electric furnace 7 is controlled by the valve 13 and the exhaust device 14, respectively. The molten metal supplied from the nozzle 3 onto the dish-shaped rotating disk 4 becomes fine droplets and scatters due to the centrifugal force of the dish-shaped rotating disk 4, and is cooled under reduced pressure to become solid particles. The generated solid particles are supplied from the discharge pipe 6 to the automatic filter 15 and separated. Reference numeral 16 is a fine particle recovery device.

The process of cooling and solidifying the molten metal from high temperature melting is important for forming the metal particles of the present invention.
For example, the following conditions can be mentioned.
The melting temperature of the metal in the melting furnace 7 is set to 600 ° C. to 800 ° C., and the molten metal is supplied from the nozzle 3 onto the dish-shaped rotating disk 4 while maintaining the temperature.
As the dish-shaped rotating disk 4, a dish-shaped disk having an inner diameter of 60 mm and a depth of 3 mm is used, and the rotation speed is 80,000 to 100,000 rpm.
As the granulation chamber 1, ^{a vacuum chamber having the ability to reduce the pressure to about 9 × 10-2} Pa is used to reduce the pressure, and then exhaust is performed simultaneously while supplying nitrogen gas at 15 to 50 ° C. The atmospheric pressure in 1 is 1 × 10 ^-1 Pa or less.

The composition of the intermetallic compound in the metal particles of the present invention is, for example, Sn40 to 60, Cu30 to 50, Ni4 to 9, Ge0.001 to 0.01 as the ratio of the atomic numbers of Sn, Cu, Ni, and Ge. is there.

The proportion of the intermetallic compound in the metal particles of the present invention is, for example, 20 to 60% by mass, preferably 30 to 40% by mass, based on the total amount of the metal particles.
The composition and proportion of the intermetallic compound can be satisfied according to the production conditions of the metal particles.

The metal particles of the present invention preferably have at least one part of the Sn—Cu alloy and the intermetallic compound endutally bonded. As described above, in the endotactic junction, an intermetallic compound is precipitated in a substance to be a metal / alloy (in the present invention, a matrix phase containing Sn and a Sn—Cu alloy), and Sn—Cu is in the middle of this precipitation. The alloy and the intermetallic compound are bonded at the crystal lattice level to form crystal grains. By forming an endotactic junction, the problem of brittleness of the intermetallic compound can be solved, and the decrease in mechanical strength due to the change in the crystal structure of Sn described below can be suppressed, and further higher heat resistance, junction strength and mechanical strength can be suppressed. A strong bonding material can be provided. The present inventors have confirmed that the joint layer structure formed by using the metal particles of the present invention maintains the end-tactical bonding of the metal particles.
The endotic bonding of the metal particles of the present invention can be formed according to the conditions for forming the metal particles of the present invention, in which the molten metal is cooled and solidified from high temperature melting.

The crystal structure of Sn is tetragonal in the temperature range of about 13 ° C. to about 160 ° C. (Sn having a tetragonal crystal structure is referred to as β-Sn), and in the lower temperature range, it is cubic (cubic). Sn having a tetragonal crystal structure is referred to as α-Sn), and the crystal structure changes. Further, the crystal structure of β-Sn changes to an orthorhombic crystal of a high-temperature phase crystal in a temperature region exceeding about 160 ° C. (Note that Sn having an orthorhombic crystal structure is referred to as γ-Sn). It is generally known that a large volume change occurs, especially at the time of a phase transition between tetragonal β-Sn and cubic α-Sn.
The metal particles of the present invention contain high temperature phase crystals even at about 160 ° C. or lower (for example, at room temperature). For example, when the bonding material containing the metal particles is heated in the bonding process, the bonding material is in a semi-molten state in which the bonding material is not completely melted, and a state in which the intermetallic compound and the parent phase are included in the endotic bonding. The state containing high temperature phase crystals is maintained even in the temperature range of 160 ° C. or lower after cooling. Then, even if the temperature of the high-temperature phase crystal is lowered to a certain extent, the phase transition of the square crystal to the low-temperature phase crystal β-Sn is unlikely to occur, and for Sn which does not undergo the phase transition to the square β-Sn, α The phase transition to −Sn does not occur, and the large volume change associated with the phase transition to α-Sn due to the decrease in temperature does not occur. Therefore, a Sn-containing bonding material having a high-temperature phase crystal even in a temperature region of 160 ° C. or lower (for example, even at room temperature) has a high-temperature crystal phase in another bonding material containing Sn in the composition (that is, even in a temperature region of 160 ° C. or lower). The volume change due to temperature change is reduced as compared with the one not intentionally included).
Further, various metals such as Cu, Ag, Au, and Ni are used for electronic components, and Sn is satisfactorily bonded to these various metals.
Therefore, the metal particles of the present invention contain a high temperature phase crystal phase in a wide temperature range (for example, even at room temperature), and by avoiding the occurrence of a tetragonal low temperature phase β-Sn as much as possible, the metal particles are tetragonal due to temperature changes. It is particularly fine because it has the property that it is unlikely to cause a large volume change due to the phase transition from β-Sn of crystals to α-Sn of tetragonal crystals, and it also bonds well with various metals used for electronic parts. It is useful as a bonding material for joints.

The effect of suppressing the change in the crystal structure of Sn is satisfactorily exhibited by the endotactic bonding in the metal particles.

Further, in the metal particles of the present invention, the endotactic bonding is preferably 30% or more, more preferably 60% or more, assuming that the entire bonding surface between the matrix and the intermetallic compound is 100%. The ratio of the endotactic junction can be calculated, for example, as follows.
An electron micrograph is taken of the cross section of the metal particles as shown in FIG. 1 below, and the joint surface between the intermetallic compound and the Sn—Cu alloy is arbitrarily sampled at 50 points. Subsequently, the joint surface is image-analyzed to examine how much end-tactical joint as shown in FIG. 4 below exists with respect to the sampled joint surface.

In the bonding layer structure portion of the present invention, the metal particles are processed into a sheet or paste, and the metal particles are held at 160 ° C. to 180 ° C. for 3 minutes or more in a state of being in contact with the object to be bonded and melted at 235 ° C. to 265 ° C. It is obtained by solidifying after being allowed to form a good bond between the objects to be joined.
The sheet containing the metal particles of the present invention as a material can be obtained by pressing the metal particles with a roller as follows, for example. That is, the metal particles of the present invention are supplied between a pair of pressure welding rollers rotating in opposite directions, and heat of about 100 ° C. to 150 ° C. is applied to the metal particles from the pressure welding rollers to pressure-weld the metal particles. To obtain a sheet.

Further, the metal particles of the present invention can be mixed in the organic vehicle to obtain a conductive paste.

The sheet or the conductive paste may be mixed with metal particles by adding other particles such as SnAgCu-based alloy particles, Cu, Cu alloy particles, Ni, Ni alloy particles or a mixture thereof. These other particles may be coated with a metal such as Si, if desired.
For example, by combining Cu or Ni alloy particles having higher conductivity than Sn and metal particles, a metal bonding layer having good conductivity and suppressed volume change in a relatively wide temperature range can be obtained.

The proportion of the metal particles of the present invention in the sheet or the conductive paste is, for example, 50% by mass or more, preferably 70 to 80% by mass.

FIG. 8 is a schematic cross-sectional view for explaining the structure of the joint layer structure portion in the present invention.
In FIG. 8, the bonding layer structure portion 300 joins the metal / alloy bodies 101 and 501 (Cu electrodes in FIG. 8) formed on the substrates 100 and 500 arranged to face each other. The bonding layer structure portion 300 has an intermetallic compound 3004 containing Sn, Cu, Ni and Ge in the matrix 3002 containing Sn and Sn—Cu alloy, and preferably between the Sn—Cu alloy and the metal. At least one portion of the compound is endotactically bonded and the matrix is bonded to the metal or alloys 101, 501.
Further, in the joint layer structure portion 300, on the joint surface with the metal / alloy bodies 101 and 501, the parent phase (Sn—Cu alloy) and the metal / alloy bodies 101 and 501 may form an endotactic joint. it can. Further, even if the metals / alloy bodies 101 and 501 are made of materials having different coefficients of thermal expansion (for example, Si and Cu), the junction layer structure portion 300 of the present invention has a skeleton structure of an intermetallic compound described in the following examples. Therefore, even if distortion occurs due to a difference in the coefficient of thermal expansion between the Si chip and the Cu substrate, excellent heat resistance can be imparted and excellent bonding strength and mechanical strength can be maintained.

The substrates 100 and 500 include semiconductor elements and constitute, for example, electronic and electrical equipment such as power devices, and the metal / alloy bodies 101 and 501 serve as electrodes, bumps, terminals, lead conductors and the like. It is a connecting member integrally provided on the 500. In electronic and electrical equipment such as power devices, the metal / alloy bodies 101 and 501 are generally configured as Cu or an alloy thereof. However, the portion corresponding to the substrates 100, 500 does not exclude the one composed of a metal / alloy body.

As described above, the bonded layer structure portion of the present invention can be formed by using the metal particles of the present invention. It has been confirmed by the present inventors that the bonded layer structure portion of the present invention obtained after heating using the metal particles has a crystal structure similar to the crystal structure of the metal particles.

That is, the composition of the bonding layer structure portion of the present invention contains, for example, 0.7 to 40% by mass of Cu, 0.1 to 5% by mass of Ni, and 0.001 to 0.01% by mass of Ge, and is preferable. It contains 1 to 15% by mass of Cu, 1 to 3% by mass of Ni, and 0.001 to 0.01% by mass of Ge.
Further, the composition of the intermetallic compound in the bonding layer structure portion of the present invention is, for example, Sn40 to 60, Cu30 to 50, Ni4 to 9, Ge0.01 to 0 as the ratio of the atomic numbers of Sn, Cu, Ni and Ge. It is .06.
The intermetallic compound contains 60 to 95% by mass of Sn, 4 to 40% by mass of Cu, 0.1 to 5% by mass of Ni, and 0.01 to 0.06% by mass of Ge.
The proportion of the intermetallic compound in the joint layer structure portion of the present invention is, for example, 50 to 90% by mass, preferably 60 to 80% by mass, based on the joint layer structure portion.

In the bonding layer structure portion of the present invention, it is preferable that at least one portion of the Sn—Cu alloy and the intermetallic compound is endically bonded. The endotactic bonding is preferably 30% or more, more preferably 60% or more, assuming that the entire bonding surface between the Sn—Cu alloy and the intermetallic compound is 100%.

Further, in the bonding layer structure portion of the present invention, the Sn—Cu alloy and the intermetallic compound have an endpoint bonding in the bonding layer structure portion and epitaxially bond with the metal / alloy bodies 101 and 501. Can be a structure.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited to the following examples.

Example 1
Using a raw material having a composition of 8% by mass Cu, 1% by mass Ni, 0.001% by mass Ge and Sn as the raw material, metal particles 1 having a diameter of about 3 to 40 μm were produced by the production apparatus shown in FIG. ..
At that time, the following conditions were adopted.
A melting pot was installed in the melting furnace 7, the above raw materials were put therein, and the metal was melted at 650 ° C., and the molten metal was supplied from the nozzle 3 onto the dish-shaped rotating disk 4 while maintaining the temperature.
As the dish-shaped rotating disk 4, a dish-shaped disk having an inner diameter of 60 mm and a depth of 3 mm was used, and the rotation speed was 80,000 to 100,000 rpm.
As the granulation chamber 1, ^{a vacuum chamber having the ability to reduce the pressure to about 9 × 10-2} Pa is used to reduce the pressure, and then exhaust is performed simultaneously while supplying nitrogen gas at 15 to 50 ° C. The atmospheric pressure in 1 was set to 1 × 10 ^-1 Pa or less.

The obtained metal particles 1 had a cross section as shown in FIG.
FIG. 3 shows the result of element mapping analysis by EDS of the cross section of the metal particle shown in FIG. From this analysis result, it was found that Cu was 10.24% by mass, Ni was 0.99% by mass, Ge was 0.001% by mass, and the balance was Sn.

The intermetallic compound in the metal particles 1 accounted for 30 to 35% by mass in the metal particles.

FIG. 4 shows a STEM image and a partial analysis result of the cross section of the metal particle obtained in Example 1 of the metal particle 1.
With reference to the upper part of FIG. 4, it can be seen that the intermetallic compound 120 composed of Sn, Cu, Ni and Ge is present in the matrix 140 containing the Sn and Sn—Cu alloy. In addition, the lattice constants (and crystal orientations) of the matrix 140 and the intermetallic compound 120 are uniform (0.3 nm in FIG. 4), and the crystals are continuously bonded at the crystal lattice level. Was confirmed. That is, according to the upper part of FIG. 4, since the lattice bonding is realized, it is confirmed that the bonding is endotactical, and the transmission electron diffraction at the interface between the matrix 140 and the intermetallic compound 120 in the lower part of FIG. 4 is confirmed. According to the pattern, it was also confirmed that there was no buffer layer between the crystals.

Further, from FIG. 4, it was found that at least a part of Sn in the metal particles of this example contained high temperature phase crystals even at room temperature.

Next, a sheet was prepared by pressure-welding the metal particles 1 with dry powder, and the sheet was used for bonding a copper substrate and a silicon element to form a bonding layer structure, and a high temperature holding test (HTS) at 260 ° C. was performed. From the start of the test to about 100 hours, the shear strength increased from about 50 MPa to about 60 MPa, and in the time region over 100 hours, the test result was obtained that it was stable at about 60 MPa.
Further, in the cold cycle test (TCT) at (-40 to 175 ° C.), a test result was obtained that the shear strength was stable at about 50 MPa over the entire cycle (1000 cycles).

FIG. 5 is an optical microscope image of a cross section of the joint portion after the copper substrate and the silicon element are bonded with a bonding material containing the metal particles 1 and subjected to a thermal shock test.
The thermal shock test was carried out at a low temperature exposure temperature of -40 ° C and a high temperature exposure temperature of 175 ° C for 1000 cycles.
From FIG. 5, it can be confirmed that the joint portion between the copper substrate and the silicon element is not collapsed, the silicon element is not broken, and a good joint state is maintained.

FIG. 9 is a TEM image showing the interface between the intermetallic compound crystal and the parent phase Sn—Cu alloy in the cross section of the bonding layer structure obtained in Example 1. The lower right portion is a transmission electron diffraction pattern at the Sn—Cu alloy-intermetallic compound crystal interface. From this TEM image and the diffraction pattern, it was clarified that the intermetallic compound has a crystal structure that is endarily bonded to the Sn—Cu alloy.

Example 2
Metal particles 2 were produced in the same manner as in Example 1 using a raw material having a composition of 8% by mass Cu, 3% by mass Ni, 0.001% by mass Ge and the balance Sn.
Next, 70 parts by mass of the metal particles 2 and 30 parts by mass of 90% by mass Cu / 10% by mass Ni alloy powder were uniformly mixed and pressure-welded with dry powder to prepare a sheet (50 μm thickness). When the sheet was used for joining a copper substrate and a silicon element and a high temperature holding test (HTS) at 260 ° C. was performed, the shear strength increased from about 60 MPa to about 70 MPa from the start of the test to about 100 hours, and 100. A test result was obtained that it was stable at about 60 MPa in the time domain exceeding the time.
Further, in the cold cycle test (TCT) at (-40 to 175 ° C.), a test result was obtained that the shear strength was stable at about 50 MPa over the entire cycle (1000 cycles).

Comparative Example 1
As a comparative example, FIG. 6 shows a STEM image of a conventional SnAgCu-based bonding material (powder solder material having a particle size of 5 μm) and an element mapping analysis result by EDS.
According to FIGS. 6A to 6D, it was confirmed that the conventional SnAgCu-based bonding material does not have an intermetallic compound and a single metal element is dispersed. It was also confirmed that the Sn—Cu alloy of the metal matrix does not have the crystal structure of the high temperature phase. With such a conventional SnAgCu-based joint material, the joint part collapses in less than 100 cycles in the cold heat cycle test (TCT) of (-40 to 175 ° C.), and the heat resistance and strength like the metal particles of the present invention. Can never be obtained.
FIG. 7 is an optical microscope image of a cross section of the joint portion after the copper substrate and the silicon element are bonded with the bonding material obtained in Comparative Example 1 and subjected to a thermal shock test.
The thermal shock test was carried out for 50 cycles at a low temperature exposure temperature of -40 ° C and a high temperature exposure temperature of 175 ° C.
From FIG. 7, it can be confirmed that the joint between the copper substrate and the silicon element has collapsed even after 50 cycles of the thermal shock test.

Example 3
With respect to the bonding layer structure produced in Example 1, a simple substance Sn contained in the bonding layer structure n was removed by using a Sn etching agent. FIG. 10 is a cross-sectional SEM photograph showing the joint layer structure portion after removing the simple substance Sn. From FIG. 10, it was found that the junction layer structure portion had a columnar intermetallic compound extending in a random direction. Since the joint layer structure has a so-called skeleton structure of a large number of columnar intermetallic compounds, even if distortion occurs due to a difference in the coefficient of thermal expansion between the Si element and the Cu substrate, the skeleton structure imparts excellent heat resistance. Also, the flexible matrix allows excellent bonding and mechanical strength to be maintained.

Although the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited thereto, and those skilled in the art can use various modifications based on the basic technical idea and teachings thereof. It is self-evident that you can think of it.

1 Granulation chamber 2 Lid 3 Nozzle 4 Dish-shaped rotating disk 5 Rotating disk support mechanism 6 Particle discharge pipe 7 Electric furnace 8 Mixing gas tank 9 Piping 10 Piping 11 Valve 12 Exhaust device 13 Valve 14 Exhaust device 15 Automatic filter 16 Fine particle recovery device 120 Intermetallic compound 140 matrix

Claims (1)

A junction layer structure that constitutes a junction of electrical and electronic equipment, and the junction layer structure contains an intermetallic compound containing Sn, Cu, Ni, and Ge in a matrix containing Sn and Sn—Cu alloy. Yes, and
The composition of the bonding layer structure portion contains 0.7 to 40% by mass of Cu, 0.1 to 5% by mass of Ni, 0.001 to 0.01% by mass of Ge, and the balance is Sn.
The composition of the intermetallic compound in the joint layer structure is 60 to 95% by mass of Sn, 4 to 40% by mass of Cu, 0.1 to 5% by mass of Ni, and 0.01 to 0.06% by mass of Ge. Including
The proportion of the intermetallic compound in the joint layer structure is 50 to 90% by mass.
The junction layer structure contains Sn having an orthorhombic crystal structure at a temperature of 160 ° C. or lower.
The joint layer structure portion includes an endotactic bond formed between the Sn—Cu alloy and the intermetallic compound, and the entire joint surface between the Sn—Cu alloy and the intermetallic compound is 100%. When the end tactical joint is 30% or more,
Joint layer structure part.

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