KR102516519B1 - Low temperature sinterable bonding material using exothermic by nano grain size and manufacturing method thereof - Google Patents

Abstract

The present invention is a method for manufacturing a bonding material containing a metal element, comprising the steps of preparing an aqueous alloy plating solution containing at least one metal salt; Forming an electrolytic plating circuit by immersing an electrode in the water-based alloy plating solution; A square pulse having a first voltage (V ₁ ) and a second voltage (V ₂ ) lower than the first voltage (V ₁ ) according to the reduction potential value of the metal salt to be plated in the controller for controlling the electroplating circuit. applying a reduction potential to the electrode by applying a voltage; and reducing the metal salt to form a metal plating film having a grain size of 10 nm to 150 nm. It relates to a method for manufacturing a low-temperature sintered joint material comprising a.
According to the present invention, in a state in which a base material is immersed in a plating bath containing two or more metal salts, a potential (voltage) is alternately applied through a power source capable of giving a potential to easily form a composite multi-layer in a short time through low-cost equipment. In addition, the plating thickness of each layer can be controlled by controlling the time and current density of each potential cycle, and the number of composite layers can be easily controlled by the number of potential cycles.

Description

Low TEMPERATURE SINTERABLE BONDING MATERIAL USING EXOTHERMIC BY NANO GRAIN SIZE AND MANUFACTURING METHOD THEREOF}

The present invention relates to a low-temperature sintering bonding material using an exothermic reaction by nano grain size and a method for manufacturing the same, and more particularly, to characteristics of sintering at a low temperature by using an exothermic reaction that appears when heating a plating layer having a nano-grain size. It relates to a method of manufacturing a low-temperature sintered joint material, which is a metal bonding medium having a low-temperature sintered joint material, and a method of joining materials to be joined at a lower temperature than conventional brazing and soldering temperatures using the low-temperature sintered joint material.

A technique related to a method of forming a multilayer thin film layer has been proposed in Patent Registration No. 0560296 and Patent Registration No. 0932694.

Hereinafter, a method for manufacturing a multilayer metal thin film and an apparatus and method for coating a multilayer thin film disclosed in Patent Registration No. 0560296 and Patent Registration No. 0932694 as prior art will be briefly described.

1 is a view showing a manufacturing method of a multi-layer metal thin film in Patent Registration No. 0560296 (hereinafter referred to as 'Prior Art 1'). As shown in FIG. 1, in the manufacturing method of the multilayer metal thin film of the prior art 1, in the manufacturing method of the metal thin film, titanium films 22 and 25 oriented in the <002> direction are formed using ionized physical vapor deposition to form 50 Å. depositing to a thickness of ˜149 Å; depositing titanium nitride films 23 and 26 oriented in a <111> direction on the titanium films 22 and 25; and depositing an aluminum film 24 oriented in a <111> direction on the stack of the titanium/titanium nitride films 22, 23, 25, and 26.

However, the multilayer metal thin film manufacturing method according to Prior Art 1 is deposited using any one of Physical Vapor Deposition (PVD), Metal Organic Chemical Vapor Deposition (MOCVD), or IPVD, which increases cost and deposits expensive equipment. The downside was that it had to be implemented through a machine.

The method of depositing a metal layer on a substrate of Patent Registration No. 0932694 (hereinafter referred to as 'Prior Art 2') includes a pretreatment step of performing plasma cleaning or ion beam cleaning on the surface of a product; a first thin film layer forming step of forming a first thin film layer by performing one of evaporation, sputtering, and reactive sputtering on the surface of the pretreated product; forming a second thin film layer by performing one of sputtering, reactive sputtering, plasma penetration, and ion beam penetration on the surface of the first thin film layer; and a repetition step of repeatedly performing the first thin film layer forming step and the second thin film layer forming step.

However, since the method of depositing a metal layer on a substrate according to the prior art 2 also constitutes a multi-layer thin film through deposition, there is a disadvantage in that it must be implemented using a deposition machine, which is expensive equipment and cost increases.

In addition, in the case of the PVD process including sputtering, since the process is performed in vacuum, vacuum equipment is essential, and the chemical thin film formation method including CVD also requires the process to be performed in vacuum, and the process temperature is high, so it is not possible to damage the substrate. can give In the case of the ALD method, raw materials are limited and the layer growth rate is slow. In the printing method including the roll printing method, it is difficult to control the thickness of the layer and it takes a long time to form the multi-layer.

Korean Patent Registration No. 10-0560296 (2006.03.06) Korean Patent Registration No. 10-0932694 (2009.12.10)

The present invention is to solve the above problems, and is a metal plating film manufactured by laminating at least one metal into a metal plating layer through electroplating. A joining member capable of being sintered is provided.

In addition, the present invention is a method for producing the multi-layer metal plating film, in which a base material is immersed in a plating bath containing at least one metal salt, and a potential (voltage) is applied through a power source to obtain a method that is safer and shorter than powder through low-cost equipment. Provided is a method for manufacturing a low-temperature sintering joint material that can be manufactured.

In addition, the present invention provides a low-temperature sintering joining method of materials to be joined such as electrical and electronic parts using the low-temperature sintering joining material as a joining medium.

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the description below.

The present invention comprises the steps of preparing an aqueous alloy plating solution containing at least one metal salt; Forming an electrolytic plating circuit by immersing an electrode in the water-based alloy plating solution; A square pulse having a first voltage (V ₁ ) and a second voltage (V ₂ ) lower than the first voltage (V ₁ ) according to the reduction potential value of the metal salt to be plated in the controller for controlling the electroplating circuit. applying a reduction potential to the electrode by applying a voltage; and reducing the metal salt to form a metal plating film having a grain size of 10 nm to 150 nm. It provides a method for producing a low-temperature sintered joint material comprising a.

In addition, the preparing of the aqueous alloy plating solution is a step of preparing an aqueous alloy plating solution containing two or more metal salts including a first metal salt and a second metal salt, and the forming of the metal plating film includes the first metal, the Forming a metal plating film including a second metal and an alloy of the first metal and the second metal, wherein the first voltage (V ₁ ) and the second voltage (V ₂ ) range from 0V to -4.5V It provides a method for manufacturing a low-temperature sintering joint material that is a voltage between.

In addition, the range of the reduction potential value of the metal salt is +1.83V to -1.67V, and a method for manufacturing a low-temperature sintered joint material is provided.

In addition, the water-based alloy plating solution provides a method for producing a low-temperature sintering joint material further comprising the metal salt, an acid, and an additive in a water-based plating solution.

In addition, the concentration ratio of the first metal salt and the second metal salt in the plating solution is in the range of 2:1 to 100:1.

In addition, the metal salts are Sn, Cu, Zn, Ni, Al, Ti, V, Cr, Mn, Fe, Co, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Provided is a method for producing a low-temperature sintering joint material comprising one or more metal salts selected from the group consisting of metal salts of Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, and Bi.

In addition, the first and second metal salts provide a method for manufacturing a low-temperature sintering joint material in which two or more metal salts of metals having a standard reduction potential difference of 0.029V or more and 1.0496V or less are selected and used.

In addition, the acid is selected from sulfuric acid, hydrochloric acid, methanesulfonitic acid (MSA), nitric acid, boric acid, acetic acid, organic sulfuric acid, citric acid, formic acid, ascorbic acid, hydrofluoric acid, phosphoric acid, lactic acid, amino acid, hypochlorous acid A manufacturing method of the bonding material is provided.

In addition, the additive is selected from among polyoxyethylene lauryl ether (POELE), a plating leveling agent (leveling agent), an accelerator, an inhibitor, a defoaming agent, a brightening agent, and an oxidation inhibitor.

In addition, the forming of the metal plating layer is a step of forming at least two or more layers, and the first voltage V ₁ is applied for a first time t ₁ to form the first plating layer, and the second voltage (V ₂ ) is applied for a second time (t ₂ ) to form a second plating layer, the first time is 0 < t ₁ ≤ 10 (min), and the second time is 0 < t ₂ ≤ 200 ( min) provides a method for manufacturing a low-temperature sintered joint material.

In addition, the preparing of the aqueous alloy plating solution is a step of preparing an aqueous alloy plating solution containing a first metal salt, and the forming of the metal plating film is a step of forming a plating film containing the first metal. The voltage (V ₁ ) is a voltage between 0V and -4.5V, and the second voltage (V ₂ ) provides a method for manufacturing a low-temperature sintering joint material having zero temperature.

In addition, the forming of the metal plating layer may include forming a plating layer by applying the first voltage V ₁ for a first time period t ₁ , and applying the second voltage V ₂ for a second time period t ₂ . It provides a method for manufacturing a low-temperature sintering joint material in which a plating layer is not formed by applying the coating layer, the first time is 0 < t ₁ ≤ 10 (min), and the second time is 0 < t ₂ ≤ 200 (min).

In addition, the metal plating film provides a method for manufacturing a low-temperature sintering bonding material in which the total thickness is formed in the range of 0.6 nm to 300 μm.

In addition, the present invention is a bonding material in which at least one or more metals are electroplated and laminated, and includes a metal plating film having a grain size of 10 nm to 150 nm, and sintered when heated to join materials to be joined, wherein the metal plating film generates heat during sintering. The reaction occurs, and when reheating after the sintering, the melting temperature (T _m2 ) is higher than the sintering temperature (T _m1 ).

In addition, the metal plating film provides a low-temperature sintering bonding material including a first plating layer and a second plating layer in which at least two or more metals are electroplated and laminated and have a grain size of 10 nm to 150 nm.

In addition, the metal is Sn, Cu, Zn, Ni, Al, Ti, V, Cr, Mn, Fe, Co, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Provided is a low-temperature sintering joint material comprising at least one metal selected from the group consisting of Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, and Bi.

In addition, when the metal is in a metal salt state, a low-temperature sintering joint material is provided in which two or more metals having a standard reduction potential difference of 0.029V or more and 1.0496V or less are selected and used.

In addition, the thickness of the entire metal plating film is 0.6 nm to 300 μm to provide a low-temperature sintering bonding material.

In addition, the metal plating film provides a low-temperature sintering bonding material having a structure in which the first plating layer and the second plating layer are repeatedly laminated 6 times or more.

In addition, the sintering temperature (T _m1 ) of the metal plating film is lower than the melting point (T _ma ) of the entire bulk composition constituting the metal plating film.

In addition, the low-temperature sintering joining material provides a low-temperature sintering joining material, which is a low-temperature joining material for joining materials to be joined by an exothermic reaction caused by densification and crystal grain growth of the metal plating film.

According to the present invention, in manufacturing a low-temperature sintered joint material, in a state in which a base material is immersed in a plating bath containing at least one or more metal salts, potential (voltage) is alternately applied through a power source to easily and within a short time through low-cost equipment It is possible to form multiple layers, and the thickness of the plating layer can be adjusted so that an exothermic reaction by the nano grain size can occur by adjusting the voltage, current density or time of each potential cycle, and two or more plating layers are repeatedly laminated to form a multilayer In this case, there is an effect that the number of multi-layers can be easily adjusted by the number of dislocation cycles.

In addition, at the time of low-temperature sintering of the materials to be joined using the low-temperature sintered bonding material according to the present invention as a bonding medium, the surface of the materials to be joined is not oxidized in a vacuum state, in an inert gas, reducing gas atmosphere, and by using a flux in the air. Bonding is possible, and noble metals as well as common metals (eg, various metals such as copper, tin, zinc, and nickel) can be plated and used as a bonding medium. The bonding medium, in which the grain size of the laminated individual plating layers made of different metals is manufactured at the level of nanometers, is sintered and bonded at a temperature lower than the melting point of the existing bulk material by an exothermic reaction generated as the grain size changes due to sintering according to heating. this is possible In addition, when the thickness of the laminated plating layer is formed at the level of nanometers, the surface area between the plating layers is widened, making it more unstable and sintering at a temperature lower than the melting point of the existing bulk material.

The melting temperature of nano-metal powder also decreases. In order to manufacture nano-metal powder, expensive precious metal powders such as gold and silver, which do not oxidize easily, are used because they have a large contact area with oxygen in the air and are easily oxidized. there is. On the other hand, the price of the bonding medium, which is a low-temperature sintering bonding material produced by the present invention, is very cheap compared to nanopowder.

In addition, unlike nanopowders, which are subject to oxidation during manufacture, the low-temperature sintered bonding material bonding medium manufactured by the present invention is plated layer by layer in a plating bath at room temperature in an air atmosphere, so that metals other than noble metals are not susceptible to oxidation (the outermost layer is There is an effect of not forming only a natural oxide film in the air.

In addition, in the present invention, the multi-layered plating film is easy to handle and has a safe effect, unlike conventional methods in which there is a risk of explosion or fire due to rapid oxidation and heat generation of nanopowder.

In addition, the present invention has an effect that can be easily mass-produced by using a plating method, unlike a method in which multiple layers are laminated by physical vapor deposition (PVD) or chemical vapor deposition (CVD), such as sputtering in vacuum. there is.

In addition, in the present invention, when a roll-shaped plating electrode is used, the low-temperature sintered bonding material can be peeled off to be manufactured as a bonding material in the form of an independent and separate foil, and there is an effect of increasing the productivity of thin plate manufacturing.

In addition, the present invention has the effect of manufacturing a low-temperature sintering bonding material capable of generating an exothermic reaction due to the nano-grain size by controlling the composition of the plating solution, the pulse, and the plating time to control the grain size and thickness of the plating layer.

In addition, in the present invention, the low-temperature sintered bonding material manufactured to have exothermic characteristics due to the nano grain size can significantly lower the bonding temperature compared to the conventional bulk type bonding medium, thereby significantly saving energy prices. . For example, the bulk material of Sn-Ag brazing material, which is widely used for bonding copper in the electronics industry, has a minimum melting point (eutectic temperature) of about 221 ° C. Copper, which is a material to be joined, is joined at 250°C. On the other hand, if the Sn-Ag-based multilayer plating film manufactured by the present invention is alternately stacked with Sn and Ag as a bonding medium, copper, which is the material to be joined, can be bonded even at a temperature of about 160 ° C, which is lower than that of the bulk material, or lower than that depending on the low-temperature sintering bonding material lamination conditions. can be joined.

In addition, in the conventional method, low-temperature bonding is performed by lowering the melting point of a nanometer-sized precious metal powder, but in the present invention, a metal plating film on which a single metal is plated or two or more different types of metal are alternately There is an effect of low-temperature sintering bonding by adjusting the grain size of the plated metal plating film to a nanometer size.

In addition, the low-temperature sintering bonding material manufactured through the present invention has a peak in the temperature range of 52.3% (Ni-Cu multilayer thin film) or more and 87.1% (Cu-Ag multilayer thin film) or less of the melting point of the existing bonding medium alloy in bulk form. Even in this temperature range where the conventional bulk bonding medium does not melt, bonding (brazing, soldering) is possible by using the low-temperature sintered bonding material according to the present invention. In addition, the bonding temperature at this time enables bonding even below the melting point of the metal constituting the plating layer. Bonding was performed at 600 ° C - 1000 ° C, which is below the melting point of 1083 ° C.

Of course, if the medium of the present invention is used, the upper limit temperature of the bonding is possible up to the melting point of the existing bonding medium or the melting point of the material to be joined, which is higher than 87.1%.

In addition, the low-temperature sintering joint material manufactured by electrolytic plating or non-electrolytic plating by alternately stacking different types of metal layers in layers becomes unstable due to an increase in the surface area between each plating layer as the individual metal layers laminated become thinner, and the low-temperature sintering joint Each plating layer constituting the material easily exhibits an exothermic reaction when the temperature is raised from a low temperature. In this case, it is sintered at a temperature lower than the melting temperature of the existing bulk material, and this low-temperature sintering phenomenon has nothing to do with the stacking order of each plating layer constituting the low-temperature sintered bonding material.

By using this, the materials to be joined can be joined at a low temperature. Therefore, there is an effect of enabling low-temperature soldering or low-temperature brazing.

1 is a schematic diagram showing a method of manufacturing a multi-layer metal thin film according to Prior Art 1;
Figure 2 is a block diagram showing a low-temperature sintering bonding material manufacturing method of the present invention.
Figure 3 is a schematic diagram of a low-temperature sintering joining material manufacturing apparatus for implementing the low-temperature sintering joining material manufacturing method of the present invention.
4 is a cross-sectional view showing a low-temperature sintered joint material manufactured by the low-temperature sintered joint material manufacturing method of the present invention.
5 is a block diagram showing a reduction potential measurement method for implementing the low-temperature sintering bonding material manufacturing method of the present invention.
FIG. 6 is a photograph of the current, potential, and recording of the plating power supply device in which the metal is plated in the first application period.
FIG. 7 is a photograph of the current, potential, repetition number settings and recording of the plating power supply for metal plating in the second application period.
8 is a graph showing whether a low-temperature sintered joint material is formed according to the content ratio of metal salts and the difference in reduction potential in the plating solution according to the present invention.
9A to 9H are cross-sectional photographs of a low-temperature sintered joint material in the case where conditions for the type and reduction potential value of the first metal salt and the second metal salt are set differently in the plating solution according to the present invention.
10 is a range graph showing whether a low-temperature sintered joint material is formed according to a content ratio of a metal salt and a difference in reduction potential in a plating solution according to the present invention.
11 is a scanning electron microscope (SEM) photograph showing a cross-section of a Sn-Cu multilayer plating film formed by the low-temperature sintering bonding material manufacturing method of the present invention.
12 is a scanning electron microscope (SEM) photograph showing a cross-section of a Sn-Cu multilayer plating film in which individual plating layers are thickly laminated by the low temperature sintering bonding material manufacturing method of the present invention.
13 is a scanning electron microscope (SEM) photograph showing a cross section of a Zn-Ni multi-layer plating film formed by the low-temperature sintering bonding material manufacturing method of the present invention.
14 is a cross-sectional view of a low-temperature sintering bonding material in which a first plating layer, a second plating layer, and a third plating layer are alternately laminated when a third metal salt is added to a metal salt according to the present invention.
15 is a graph showing conditions under which oxidation and reduction of metals are performed to explain a method of bonding at a low temperature using the low-temperature sintering bonding material of the present invention.
16 is a graph obtained by measuring the thermal characteristics of the Ni-Cu low-temperature sintered joint material prepared in the present invention by differential thermal analysis (DTA) during heating.
17 is a photograph of low-temperature sintering and bonding of 304 stainless steel at 600 ° C, 700 ° C, 800 ° C, and 1000 ° C for 10 minutes using the Ni-Cu low-temperature sintering joint material prepared in the present invention as a bonding medium.
18 is a photograph of a fracture surface obtained by performing a tensile test after low-temperature sintering and bonding of 304 stainless steel at 900 ° C. for 10 minutes using the Ni-Cu low-temperature sintering bonding material prepared in the present invention as a bonding medium.
19 is a graph measuring the thermal characteristics of the Sn-Cu low-temperature sintered joint material prepared in the present invention by differential scanning calorimetry (DSC) during heating.
20 is a photograph of the Sn-Cu low-temperature sintering bonding material manufactured in the present invention formed on a copper substrate.
21 is a photograph of low-temperature bonding of copper plates for 10 minutes at temperatures of 160 ° C, 170 ° C, and 210 ° C in a vacuum furnace of 10 ^-3 torr using the Sn-Cu low-temperature sintering bonding material prepared in the present invention as a bonding medium. am.
22 is a graph of the thermal characteristics measured by DTA during heating of the Cu-Ag low-temperature sintered bonding material prepared in the present invention.
23 shows the first and second plating layers (left) in a plated state before heating of the Sn-Cu low-temperature sintering bonding material manufactured in the present invention and the first and second plating layers disappearing due to diffusion after heating (right) is a picture of
24 shows the first and second plating layers (left) in a plated state before heating of the Ni-Cu low-temperature sintering joint material manufactured in the present invention, and the first and second plating layers disappearing due to diffusion after heating (right). is a picture of
25 is a graph showing the results of XRD analysis before and after heating of the Sn-Cu low-temperature sintered joint material and the Ni-Cu low-temperature sintered joint material prepared in the present invention.
26 is an electron microscope (SEM) photograph showing a cross-section of a multi-layered metal material having a thickness of 5 μm in the sum of the thicknesses of each of the two plating layers.
27 is a heating graph obtained by measuring thermal characteristics using a differential scanning calorimeter (DSC) after manufacturing a multi-layered metal material so that the sum of the thicknesses of each two plating layers is 5 μm.
28 is an optical microscope photograph showing an actual cross-section after bonding of a junction obtained by manufacturing a multi-layered metal material so that the sum of the thicknesses of each of the two plating layers is 5 μm.
29 is an optical micrograph showing a cross-section of a copper electrode manufactured by laminating the number of layers of a multi-layered metal material to 6 and cold-bonded.
30 is an optical microscope photograph showing a cross-section of a Sn-Cu-based metal plating thin film prepared by increasing the plating time of the multi-layer metal material and having a total plating thickness of 300 μm.

Prior to describing the present invention in detail below, it is understood that the terms used herein are intended to describe specific embodiments and are not intended to limit the scope of the present invention, which is limited only by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art unless otherwise specified.

Throughout this specification and claims, the terms "comprise", "comprise" and "comprising", unless stated otherwise, are meant to include a stated object, step or group of objects, and steps, and any other object However, it is not used in the sense of excluding a step or a group of objects or a group of steps.

On the other hand, various embodiments of the present invention can be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as being particularly desirable or advantageous may be combined with any other features and characteristics indicated as being particularly desirable or advantageous. Hereinafter, embodiments of the present invention and effects thereof will be described with reference to the accompanying drawings.

2 is a block diagram showing a method for manufacturing a low-temperature sintered joint material of the present invention, and FIG. 3 is a schematic diagram of a low-temperature sintered joint material manufacturing method for implementing the low-temperature sintered joint material manufacturing method of the present invention. 4 is a cross-sectional view showing a low-temperature sintered joint material manufactured by the low-temperature sintered joint material manufacturing method of the present invention, and FIG. 5 shows a reduction potential measurement method for implementing the low-temperature sintered joint material manufacturing method of the present invention. A block diagram is shown.

Referring to these drawings, in the low-temperature sintering bonding material manufacturing method using the plating method of the present invention, after immersing the electrodes 12, 13, and 14 in an aqueous alloy plating solution 15 containing at least one metal salt, the electrode 12 , 13, 14) to form a metal plating film having a nano grain size on the base material by applying a voltage to manufacture a low-temperature sintered joint material. In addition, after immersing the electrodes 12, 13, and 14 in an aqueous alloy plating solution 15 containing two or more metal salts including a first metal salt and a second metal salt, voltage is applied to the electrodes 12, 13, and 14. Thus, a metal plating film in which the first plating layer 33 and the second plating layer 34 having a nano grain size are alternately plated is formed to manufacture a low-temperature sintering bonding material.

In this specification, the first plating layer is theoretically a layer on which both the first metal and the second metal are reduced and plated, but since the second plating layer is plated with a small amount of the first metal, it is a layer in which the first metal is relatively mainly plated. The first metal-rich layer including an alloy of the first metal and the second metal and the second metal is also included.

In addition, the second plating layer is a layer on which the second metal is mainly plated, and theoretically means a pure second metal layer, but in practice, since an alloy of the first metal and the second metal and a small amount of the first metal are also included, the second plating layer is a layer of the concept including this. 2 means a metal-rich layer.

The fact that the first metal, the second metal, and their alloys are all included in each plating layer means that even if an applied potential theoretically reduces only a specific metal when using one electrolytic bath, due to the characteristics of actual electroplating, only one metal is not plated. , it seems to be because the rest of the metal tends to be plated as well.

As a method for implementing this, electrode and aqueous alloy plating solution preparation step (S100), electrolytic plating circuit construction step (S110), reduction potential or current application step (S120), voltage or corresponding current, time value input step (S130), and multi-layer A plating step (S140) is included.

In the present invention, the metal salt in the plating solution is in an ionized form, and a voltage higher than the reduction potential of each metal element must be applied to deposit it on the cathode using an electric current. In the case of a plating solution containing two or more metal salts, there is a standard reduction potential difference between the two elements, and accordingly, a voltage range in which the type of metal to be predominantly plated varies. When these voltage sections are alternately applied, plating layers of different types of metals to be plated in large amounts are alternately deposited. The voltage interval at this time may be represented by a first application period in which the first metal is predominantly plated and a second application period in which the second metal is predominantly plated.

As such, in the present invention, plating layers alternately deposited form a layered structure in which thin films formed in the form of wide surfaces are stacked in regular order. At this time, when the grain size of the individual metal layer in the metal plating film is reduced to the nanometer level, its characteristics are significantly different from those of the bulk metal. Specifically, since the plating layer having a nano grain size has a very large specific surface area of the surface of the particles constituting the plating layer, it tends to grow into large particles with a low specific surface area in order to reduce enthalpy. The driving force of the sintering reaction is increased by an exothermic reaction caused by an increase in enthalpy, that is, a decrease in enthalpy, so that sintering occurs at a temperature lower than the sintering temperature of a general bulk metal. In addition, when the thickness of the plating layer is formed on the order of nanometers due to the nano grain size, the surface area between each plating layer becomes unstable due to an increase in the surface area between each plating layer, so that each of the laminated plating layers easily exhibits an exothermic reaction when the temperature is raised from a low temperature. Due to this, it can be easily sintered and joined even at a temperature lower than the sintering temperature in the bulk material state. Therefore, it can play a role in enabling a bonding process, which is generally performed at a high temperature, to be performed at a low temperature.

Here, the low-temperature sintering joining material manufacturing apparatus 10 for implementing the low-temperature sintering joining material manufacturing method using the plating method of the present invention includes a container 11, a reference electrode 12, an anode 13, a cathode 14, a stirring It includes a magnetic 16 and a PC 20 as a control unit.

The container 11 is a plating bath in which the open top is closed with a stopper 11a and a magnetic stirrer 16 is installed on the inner bottom.

As the reference electrode 12, a saturated calomel electrode was used. A 10 mm X 0 mm platinum (Pt) electrode was used as the anode 13 electrode, and a 10 mm X 0 mm copper (Cu) electrode was used as the cathode 14 electrode. The anode and cathode can use different types of conductive metals depending on the plating conditions, and the size can be adjusted. As a power source, both a constant current and a constant voltage can be used.

The stirring magnet 16 is disposed on the bottom surface of the container 11 to stir the plating solution stored in the container 11, and a driving magnet (not shown in the drawing) is provided on the drive shaft at the bottom of the container 11. When the driving motor (not shown in the drawing) is driven, the driving magnet is operated by using the principle of interlocking the magnetic stirring magnet 16 disposed on the bottom surface of the container 11 by the magnetic force.

As a controller, the PC 20 is installed with software such as a power source capable of controlling voltage and current waveforms and a waveform control program, and can control voltage and current waveforms through input and manipulation. On the other hand, in the PC 20, the anode 17 of the power source is installed to be electrically connected to the anode 13 through a wire, and the reference electrode 18 of the power source is electrically connected to the reference electrode 12 through a wire. is installed, and the negative electrode 19 of the power source is installed so that it is electrically connected to the negative electrode 14 through a wire.

The electrode and aqueous alloy plating solution preparation step (S100) is a step of preparing and manufacturing the electrode and the aqueous alloy plating solution 15, respectively. At this time, the electrode includes a reference electrode 12, an anode 13 and a cathode 14. The plating solution 15 includes a metal salt, and may further include an acid and an additive. When a metal plating film is formed with at least one metal, the metal salt includes a first metal salt, and when two or more different types of metals are alternately stacked to form a metal plating film, the metal salt includes a first metal salt and a second metal salt. included

Here, the first and second metal salts are tin (Sn), copper (Cu), zinc (Zn), nickel (Ni), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), manganese ( Mn), Iron (Fe), Cobalt (Co), Gallium (Ga), Germanium (Ge), Arsenic (As), Zirconium (Zr), Niobium (Nb), Molybdenum (Mo), Ruthenium (Ru), Rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), antimony (Sb), tellurium (Te), hafnium (Hf), tantalum (Ta), tungsten (W), Includes metals such as rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), thallium (Tl), lead (Pb), and bismuth (Bi), and includes two or more different types In the case of a multi-layered metal plating film in which metals are alternately stacked, two or more metal salts of elements having standard reduction potentials differing in the range of 0.029V or more and 1.0496V or less may be selected and used. In addition, the concentration ratio of the first and second metal salts in the plating solution is preferably selected from the range of 2:1 to 100:1. At this time, in this embodiment, it is exemplified that multi-layer plating is performed by selecting Cu, Sn, Pb, Bi, Ag, Ni, and Zn, which have the highest utilization.

Among two or more metal salts used as the first metal salt and the second metal salt, a metal having a relatively high standard reduction potential is referred to as a first metal salt, and a metal having a relatively low standard reduction potential is referred to as a second metal salt. In this specification, based on the standard reduction potential (0.000V) of the standard hydrogen electrode, the degree to which the metal ion of the corresponding metal salt is more difficult to reduce than the hydrogen ion is compared, and the more difficult it is to reduce than the hydrogen ion, the higher the standard reduction potential. The sign of the standard reduction potential is (-), and the larger the absolute value, the higher the standard reduction potential.

And in the case of acids, hydrochloric acid, sulfuric acid, methanesulfonitic acid (MSA), nitric acid, boric acid, acetic acid, organic sulfuric acid, citric acid, formic acid, ascorbic acid, hydrofluoric acid, phosphoric acid, lactic acid, amino acid, hypochlorous acid, etc. are ionized to conduct electricity. An easy acid can be used, and in the embodiment, sulfuric acid, which is easy to obtain at low cost, was used.

In addition, additives are used to make the surface of the plating film uniform, and a leveling agent (smoothing agent), an accelerator, and an inhibitor may be added. In addition, various additives such as a defoaming agent, a polishing agent, and a particle refiner may be used depending on the case. In the embodiment, polyoxyethylene lauryl ether (POELE) among the leveling agents was used as an additive, but it is possible to form a multilayer film without using it.

The electrolytic plating circuit configuration step (S110) is a step of immersing the reference electrode 12, the anode 13, and the cathode 14 in the aqueous alloy plating solution 15 and then connecting power to configure the electrolytic plating circuit. That is, in the electrolytic plating circuit configuration step (S110), the electrons of the circuit move in the order of the anode 13, the power supply, and the cathode 14.

The reduction potential or current application step (S120) is a step of inputting and applying a reduction potential (voltage) or current through the software of the PC 20 as a control unit. At this time, when the reduction potential or current applying step (S120) is performed, voltage or current is input in the form of a square pulse. In the case of forming a metal plating film with at least one type of metal, the pulse voltage and current are applied so that the first application period in which metal is plated and the second application period in which metal is not plated are repeated, and two or more different types of metal are alternately applied. When the metal plating film is formed by stacking, the pulse voltage and current are applied so that the first application period in which the first metal is predominantly plated and the second application period in which the second metal is predominantly plated are repeated.

Each section may be represented by a change in input voltage or current over time, that is, plating voltage (or current) and duration, and in the first applying section, a first voltage (or current corresponding thereto) is applied for a first time and , The second applying period represents a pulse shape in which a second voltage (or current corresponding thereto) is applied for a second time.

In the step of inputting the thickness condition of the plated thin film (S130), the voltage corresponding to the plating thickness having the desired heat generation characteristic for the first plated layer 33 and the second plated layer 34 or the corresponding current, time, and number of cycles is input to the PC 20. This step is entered through the software of

When a metal plating film is formed with at least one metal, the first applying period in which the plating layer is formed is a period in which the first voltage V ₁ is applied for the first time t ₁ , and the first voltage V ₁ is A voltage between 0V and -4.5V, more preferably between 0V and -1.67V is applied.

The thickness of the plating layer is controlled by controlling the first time (t ₁ ), and the first time (t ₁ ) is the grain of the plating layer formed in one first application period within the range of 0 < t ₁ ≤ 10 (min) The first time (t ₁ ) is determined so that the size is 10 nm to 150 nm.

When a metal plating film is formed with at least one metal, the second applying period in which no plating layer is formed is a period in which the 0V voltage is applied for a second time period (t ₂ ), and the second time period (t ₂ ) is 0 < t ₂ ≤ 200 (min), and the second time period (t ₂ ) is preferably 0.5 to 20 times the first time period (t ₁ ).

When two or more different types of metals are alternately stacked to form a metal plating film, the first application period in which the first plating layer 33 is formed is a period in which a first voltage V ₁ is applied for a first time period t ₁ . As, the first voltage (V ₁ ) is applied as a voltage between 0V and -4.5V, more preferably between 0V and -1.67V. The first voltage V ₁ is applied as a voltage at which the first metal is predominantly plated.

The thickness of the first plating layer is controlled by adjusting the first time (t ₁ ), and the first time (t ₁ ) is a first application period formed in one first application period within the range of 0 < t ₁ ≤ 10 (min). The first time (t ₁ ) is determined so that the single thickness of one plating layer is 10 nm to 150 nm.

In addition, the second application period in which the second plating layer 34 is formed is a period in which the second voltage V ₂ is applied for a second time period t ₂ , and the second voltage V ₂ is between 0V and -4.5V. A voltage of, more preferably, a voltage between 0V and -1.67V is applied.

The thickness of the second plating layer is controlled by adjusting the second time period (t ₂ ), and the second time period (t ₂ ) is formed in one second application period within the range of 0 < t ₂ ≤ 200 (min). The second time is determined so that the single thickness of the two plating layers is 10 nm to 150 nm. Also, the second time period t ₂ is preferably 0.5 to 20 times the first time period t ₁ .

When the case where the first application period and the second application period are plated once each is referred to as one cycle, the bonding material according to the present invention is at least one cycle, and at least one first plating layer and at least one second plating layer are applied. A plating layer is included. Preferably, the first plating layer of at least 6 layers or more and the second plating layer of at least 6 layers are repeatedly formed in 6 cycles or more.

The first time (t ₁ ) and the second time (t ₂ ) are set to 1 so that the total thickness of the metal plating film including at least one first plating layer and at least one or more second plating layer is repeatedly formed to be 0.6 nm to 300 μm. Adjusts the total time repeated over the cycle.

That is, in the step of inputting the thickness condition of the plated thin film (S130), the thickness of the plating layer in the first and second sections can be adjusted by adjusting the voltage between 0V and -4.5V or the corresponding current and time values according to the thickness condition. Preferably, in the present invention, the thickness of the plating layer of the first and second sections can be adjusted by adjusting the voltage between 0V and -1.67V or the corresponding current and time values.

Elements with a reduction potential higher than -1.67V (for example, Li, Na, Ca, etc.) are difficult to manufacture due to reduction by the plating method of the present invention. In addition, when the voltage is less than 0V, there is a problem in that the plating layer is not well formed due to metal etching.

The multi-layer plating step ( S140 ) is a step of obtaining a low-temperature sintered joint material through sequential plating of a single plating layer or the first plating layer 33 and the second plating layer 34 . The metal salt in the plating solution is reduced in an ionized form and deposited on the cathode, so that a voltage higher than the reduction potential of each element must be applied. As described above, the first voltage (or current corresponding thereto) and the second voltage (or Corresponding current) is repeatedly applied so that the layer in which the metal is precipitated appears repeatedly, or the plating layer in which the first metal is predominately precipitated and the plating layer in which the second metal is predominately precipitated alternately and repeatedly appears. As the number of plated layers increases, the surface area between the plated layers increases and becomes unstable. However, the current density during plating should not exceed the limit current density.

On the other hand, the low-temperature sintered bonding material is obtained after one cycle of repeating the first application period and the second application period once so that the plating layer of a single metal or the first plating layer 33 and the second plating layer 34 can exhibit exothermic characteristics. The thickness of the formed single metal plating layer or the sum of the thicknesses of the first plating layer 33 and the second plating layer 34 is formed in a range of 0.1 nm to 5 μm.

In addition, in the low-temperature sintering bonding material, it is preferable that the plating layer of a single metal or the metal plating film including the first plating layer 33 and the second plating layer 34 be a multi-layer metal plating film having a laminated structure of at least six layers. . If these metal plating layers are less than 6 layers, densification, which mainly occurs between plating layers during sintering during bonding, may not be achieved, resulting in poor bonding strength and reduced bonding reliability, which is not preferable.

Moreover, the number of multilayers can be easily adjusted by the number of potential cycles when the multilayer plating step (S140) is performed.

In addition, by measuring the difference in reduction potential between the first metal salt and the second metal salt, applying a reduction potential or current for manufacturing a low-temperature sintered joint material in which the first plating layer 33 and the second plating layer 34 are alternately plated according to the present invention Step S120 may be performed.

At this time, the step of measuring the difference in reduction potential of the metal salt is alloy plating solution preparation step (S200), electrode preparation step (S210), electroplating circuit construction step (S220), power application step (S230), polarization curve measurement step (S240). ) and measuring the reduction potential and current of the metal to be plated (S250), the reason for measuring the reduction potential of the metal salt is to give a voltage higher than the potential at which these metals are reduced to form the first plating layer and the second plating layer. am.

Here, the alloy plating solution manufacturing step (S200), electrode preparation step (S210), electrolytic plating circuit configuration step (S220), and power application step (S230) are the configuration steps of the low-temperature sintering bonding material manufacturing method, and the electrode and water-based alloy Since it corresponds to the plating solution preparation step (S100), the electrolytic plating circuit construction step (S110), and the reduction potential or current application step (S120), detailed descriptions are omitted.

In addition, if the reduction potential is known, the low-temperature sintering joint material manufacturing method can be executed immediately. Meanwhile, the polarization curve measurement step (S240) and the reduction potential and current measurement step (S250) of the metal to be plated do not need to be performed again after being performed only once. Furthermore, a method for measuring the difference in reduction potential is to measure a Tafel curve (when a constant voltage per unit time is changed and the current density at that time is represented as a hysteresis curve, a section in which a change in slope appears as a reduction potential) is measured.

As a result, the low-temperature sintered joint material manufactured by the low-temperature sintered joint material manufacturing method of the present invention can easily form laminates up to nanometer thickness in order to have exothermic properties, and the number of laminates can be increased to tens of thousands of layers or more.

On the other hand, the low-temperature sintering joint material 30 manufactured by the low-temperature sintering joint material manufacturing method according to the present invention has an insulating tape 32 at the edge as shown in the case of forming a multi-layer metal plating film with a single metal (not shown) When a single plating layer is repeatedly laminated on the conductive substrate 31 finished with, and two or more different types of metals are alternately laminated to form a multi-layer metal plating film, as shown in FIG. 4, the first plating layer 33 and the second plating layer 34 are sequentially laminated.

The low-temperature sintering bonding material is implemented in the form of alternating individual plating layers of different types from several to tens of thousands of layers, so that bonding properties can be further improved.

On the other hand, the low-temperature sintering bonding of the base material forming the low-temperature sintering bonding material is carried out in a vacuum, inert gas, or reducing gas atmosphere that does not cause oxidation of the bonding surface, and can be carried out using a flux even in the atmosphere. .

The low-temperature sintering bonding material is in the form of a multi-layered plating film plated on the surface of the base material, in addition to the form of a multi-layered thin film foil sheet, in the form of pulverized particles of the multi-layered thin film foil sheet, powder or balls formed with the low-temperature sintered bonding material on the particle surface , In the form of one or more types selected from the group consisting of pulverized particles of a multilayer thin film foil sheet or powder formed by mixing a low-temperature sintered bonding material with a liquid, it may be disposed at the junction of the base material and used as a bonding medium.

As the liquid in the paste form prepared above, for example, alcohols, phenols, ethers, acetones, aliphatic hydrocarbons having 5 to 18 carbon atoms, kerosene, light oil, toluene, aromatic hydrocarbons such as xylene, silicone oil, etc. can be used as solvents. Among them, preferably, alcohols, ethers, or acetones having some degree of solubility in water may be used.

In addition, the base material (material to be joined) may be selected and used from the group consisting of metal, ceramic, and polymer material.

The base material (material to be joined) forming the low-temperature sintering bonding material according to the present invention has an exothermic characteristic, and can be bonded at a lower temperature than conventional bonding media in bulk form.

In addition, the low-temperature sintering bonding material is preferably a low-temperature sintering bonding material for bonding the base material and the material to be joined by an exothermic reaction due to the nano grain size. That is, the low-temperature sintered bonding material whose grain size is changed by sintering can easily and stably perform bonding at low temperature when bonding the base material and the material to be joined, and has excellent bonding strength by bonding the base material and the material to be joined more firmly and stably. indicates

The present invention also provides a bonding material comprising a metal plating film having a grain size of 10 nm to 150 nm, in which at least one or more metals are electroplated and laminated, and sintered during heating to join materials to be joined.

In addition, at least two or more metals are electroplated and laminated, and a bonding material including a metal plating film including a first plating layer and a second plating layer having a grain size of 10 nm to 150 nm is provided. In addition, the bonding material including at least two or more metals includes at least two or more layers of amorphous metal plating.

When the metal plated film is sintered, an exothermic reaction occurs, and when reheating after the sintering, the melting temperature (T _m2 ) is higher than the sintering temperature (T _s1 ).

Here, the low-temperature sintering bonding material has a structure in which the metal plating film is stacked in six or more layers, and can be used as a bonding material at a temperature lower than the melting temperature of the entire bulk composition constituting the plating layer of the metal plating film, and the bonding material It can be used as a low-temperature sintering bonding material for bonding a base material and a material to be joined by an exothermic reaction of a plating layer having a nano grain size.

In addition, the metal is Sn, Cu, Zn, Ni, Al, Ti, V, Cr, Mn, Fe, Co, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In , Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, one or more metals selected from the group consisting of Pb and Bi may be used, preferably in a metal salt state, standard reduction Two or more metals with potential differences can be selected and used.

On the other hand, the metal plating film is preferably formed to a thickness ranging from 0.6 nm to 300 μm in total thickness, and in the case of forming a metal plating film with a single metal, it is preferable that single plating layers having a grain size of 10 nm to 150 nm are stacked, , When two or more different types of metals are alternately laminated to form a multilayer metal plating film, the sum of the thicknesses of the two plating layers is preferably implemented with a thickness ranging from 0.1 nm to 5 μm.

The bonding material according to the present invention can sinter and bond a base material and a material to be joined at a low temperature by an exothermic reaction of a plating layer having a nano grain size, and has excellent heat resistance characteristics after bonding.

More specifically, the bonding material according to the present invention is sintered at a temperature lower than the melting point (T _ma ) of the entire bulk composition constituting the metal plating film during heating for bonding. That is, when the temperature at which sintering occurs when the bonding material according to the present invention is first heated is referred to as the sintering temperature (T _s1 ), T _s1 < T _ma .

An exothermic reaction occurs during sintering of the metal plating film of the joining material, and when reheating after the sintering, the melting temperature (T _m2 ) is higher than the sintering temperature (T _s1 ).

This is because a metal plating film including a plating layer having a nano grain size undergoes densification between the plating layers and grain growth in the plating layer by heating, and an exothermic reaction occurs during this process. The bonding material, in which the grain size of the laminated individual plated metal layers made of single or dissimilar metals reaches the nanometer level, has the characteristic of growing into large particles with a low specific surface area by attaching small particles with a very large specific surface area to each other (sintering The driving force of the reaction) appears, and due to this characteristic, an exothermic reaction (enthalpy decrease) occurs, which further increases the driving force of the sintering reaction, so that sintering occurs at a temperature lower than the melting point (T _ma ) of the entire bulk composition constituting the metal plating film. It happens. In addition, the surface area between stacked individual plated metal layers made of single or different metals is widened, making it more unstable, and sintering occurs at a temperature lower than the melting point (T _ma ) of the entire bulk composition constituting the metal plated film.

In addition, when the bonding material according to the present invention is heated again after cooling it after bonding the base material and the material to be joined in the first sintering furnace, melting does not occur at the sintering temperature (T _s1 ) and melting occurs at a temperature higher than the sintering temperature (T _s1 ) It happens. That is, when the bonding material according to the present invention is heated again after being cooled for the first time, the melting temperature (T _s2 ) is T _s2 > T _s1 .

This is because when bonding materials are bonded, multilayer thin films disappear due to densification between plating layers and grain growth in the plating layers by heating, and in this process, the first metal and the first metal and It is due to alloying of the second metal. The bonding material melts at a temperature higher than the sintering temperature when reheated after cooling due to bulking or alloying of constituent metals during initial heating. When the bonding material according to the present invention is heated to bond the base material and the material to be joined, it changes from an unstable state to a stable state and has excellent heat resistance because melting occurs at a temperature higher than the sintering temperature.

The low-temperature sintering bonding material according to the present invention will be described in detail through the following drawings and examples.

FIG. 6 shows the current and potential of plating the first plating layer in the first section and a recorded photograph of the plating power supply device, and FIG. 7 shows the plating current, potential, number of repetitions and plating in the second section. A recorded photograph of the power supply unit is disclosed.

8 shows a table showing whether a low-temperature sintered joint material is formed according to the content ratio of the metal salt and the difference in reduction potential in the plating solution according to the present invention, and FIGS. 9a to 9h show a first metal salt and A cross-sectional photograph of a low-temperature sintering joint material in the case where the type of second metal salt and the reduction potential value conditions are set differently, and FIG. A range graph showing whether a material is formed is shown.

11 shows a scanning electron microscope (SEM) photograph showing a cross-section of a Sn-Cu multi-layer plating film formed by the low-temperature sintering joint material manufacturing method of the present invention, and FIG. A scanning electron microscope (SEM) photograph showing a cross section of a Sn-Cu multilayer plating film in which individual plating layers are stacked thickly is disclosed, and FIG. 13 shows a Zn-Ni multilayer plating film formed by the low temperature sintering bonding material manufacturing method of the present invention A scanning electron microscope (SEM) photograph showing a cross section is disclosed, and FIG. 14 is low temperature sintering in which a first plating layer, a second plating layer, and a third plating layer are alternately laminated when a third metal salt is added to the metal salt according to the present invention. A cross-sectional view of the bonding material is shown.

15 is a graph showing the conditions under which oxidation-reduction of metal is performed in order to explain a method of bonding at a low temperature using the low-temperature sintering bonding material of the present invention.

16 shows a graph obtained by measuring the thermal characteristics of the Ni-Cu low-temperature sintered joint material prepared in the present invention by DTA (Differential Thermal Analysis) during heating, and FIG. A photograph of low-temperature bonding of 304 stainless steel at 600 ° C, 700 ° C, 800 ° C, 1000 ° C for 10 minutes using the material as a bonding medium is disclosed, and FIG. A photograph of a fracture surface obtained by performing a tensile test after low-temperature bonding of 304 stainless steel at 900° C. for 10 minutes using a bonding medium is disclosed.

19 shows a graph measuring the thermal characteristics of the Sn-Cu low-temperature sintered joint material prepared in the present invention by DSC (Differential scanning calorimetry) during heating, and FIG. 20 shows a low-temperature sintered joint material manufacturing method according to the present invention. A photograph in which the Sn-Cu low-temperature sintered joint material is formed on a copper substrate is disclosed, and FIG. Alternatively, there is disclosed a photograph in which a copper plate is bonded at a low temperature for 10 minutes at each temperature of 160°C, 170°C, and 210°C in a vacuum furnace of 10 ^-3 torr.

22 shows a graph obtained by measuring the thermal characteristics of the Cu-Ag low-temperature sintered joint material manufactured by the low-temperature sintered joint material manufacturing method according to the present invention by DTA during heating, and FIG. 23 shows a low-temperature sintered joint material according to the present invention. Pictures (left) of the first and second plating layers in the plated state of the Sn-Cu low-temperature sintering joint material manufactured by the manufacturing method (left) and pictures (right) of the disappearance of the first and second plating layers after heating are disclosed. has been 24 is a photograph (left) of the first and second plating layers of the Ni-Cu low-temperature sintering bonding material manufactured in the present invention in a plated state before heating (left) and a photograph of the first and second plating layers disappearing after heating (right) is disclosed.

25 is a graph (a) and a Ni-Cu low-temperature sintered joint material showing characteristics of increased crystallinity due to an increase in particle size after heating as a result of XRD analysis before and after heating of the Sn-Cu low-temperature sintered joint material prepared in the present invention. As a result of XRD analysis before/after heating of , a graph (b) showing the characteristics of increased crystallinity due to an increase in particle size after heating is disclosed.

26 shows an electron microscope (SEM) photograph showing a cross-section of a multilayer metal material having a thickness of the sum of two plating layers of 5 μm, and FIG. A heating graph in which the thickness of each of the two plating layers is 5 μm is disclosed. An optical micrograph showing an actual cross section after bonding is disclosed, and FIG. 29 shows an optical micrograph showing a cross section of a copper electrode prepared by laminating six layers of a multilayer metal material and low-temperature bonding.

30 discloses an optical micrograph showing a cross-section of a Sn-Cu-based metal plating thin film prepared by increasing the plating time of the multilayer metal material to have a total plating thickness of 300 μm.

Hereinafter, specific embodiments of the manufacturing method of the low-temperature sintering joining material of the present invention will be described with reference to these drawings.

As an example, the process of forming a multi-layer metal plating film by the low-temperature sintering bonding material manufacturing method using the plating method of the present invention will be described.

[Example 1]

In this embodiment, plating was performed by dissolving the first metal salt and the second metal salt in an alloy plating solution at a molar ratio of 1:1 to 200:1. 8 and 9a to 9h, when the ratio of the first metal salt to the second metal salt is less than 2:1, for example, 6:4 or 5:5, the first and second plating layers The difference in concentration of the second metal is reduced so that a low-temperature sintered joint material is not formed. When the ratio of the first metal salt to the second metal salt exceeds 100:1, for example, when the ratio is 200:1, the second metal salt is easily consumed during plating, so that the concentration of the second metal salt is diluted and the second metal salt is reduced. Instead, hydrogen ions in the plating solution are reduced to generate hydrogen bubbles. Therefore, it becomes difficult to form a low-temperature sintered joint material.

In addition, in order to determine the first and second metal salts forming the low-temperature sintered joint material, multi-layer plating was performed by selecting metal salts of elements having a standard reduction potential difference of 0.004 V or more and 1.5614 V or less (FIGS. 8 and 9a). to Figure 9h). When the difference in reduction potential between the first and second metal salts becomes less than 0.029 V, when the first and second plating layers are formed, both the first and second metal salts are reduced and the boundary between the plating layers disappears, so that a multi-layered thin film is not formed. In addition, when the difference in reduction potential between the first and second metal salts exceeds 1.0496 V, the second metal interferes with the plating of the first metal, so that the boundary between the plating layers also disappears, preventing the formation of a multi-layered thin film.

In addition, cross-sections of the low-temperature sintering joining material corresponding to each condition of FIG. 8 are shown in FIGS. 9A to 9H, and whether or not the low-temperature sintering joining material is formed according to the plating conditions can be confirmed with pictures. The numbers in FIGS. 9A to 9H correspond to the numbers in FIG. 8 . For example, the picture of the 2-3' condition in FIG. 8 represents the '2-3' picture in FIGS. 9A to 9H.

In FIG. 10, a range of conditions for forming multi-layer plating, which is the result of FIG. 8, is set and shown as a graph.

As a result, in order to manufacture a low-temperature sintering joint material in the manufacturing method according to the present invention, a metal salt having a difference in reduction potential between the first metal salt and the second metal salt in the plating solution in the range of 0.029V or more and 1.0496V or less is used, and the first metal salt and the second metal salt in a concentration ratio of 2:1 to 100:1.

[Example 2]

In order to form a Sn and Cu multilayer plating film, 200 ml of a sulfuric acid-based Sn-Cu alloy plating solution was prepared, and the composition is as follows.

_SnSO4 : 17.175g

CuSO ₄ 6H ₂ O: 1.998 g

H ₂ SO ₄ : 10.72ml

HCl: 0.03ml

POELE: 0.8g

The plating conditions at this time were plating voltage of -0.6V, current density of -30mA/cm ² , and plating time of 30 seconds in the first application period, and plating voltage of -0.45V and current density of -2mA in the second application period. /cm ² , and the plating time was 2 minutes. The first and second sections were repeated 400 times (400 cycles) and tested.

As a result of the plating, as shown in FIG. 11 , it can be confirmed that 400 layers of each of the Sn-rich layer having a thickness of 600 nm and the Cu-rich layer having a thickness of 100 nm are alternately plated.

When the plating current or plating time was increased using the same plating solution, the Sn and Cu layers were alternately plated thicker. The plating conditions at this time were -0.6V plating voltage, -30mA/cm ² current density, and 10 minutes plating time in the first application period, and -0.45V plating voltage and -0.45V current density in the second application period. 2 mA/cm ² , and the plating time was 10 minutes. The first and second sections were repeated 5 times (5 cycles) and tested.

As a result of plating, it can be seen in FIG. 12 that the Sn-rich layer having a thickness of 7 μm and the Cu-rich layer having a thickness of 10 μm were alternately plated in a slightly thicker layer by 5 layers each.

[Example 3]

Referring to the process of forming a Zn-Ni multi-layer plating film by the low-temperature sintering bonding material manufacturing method using the plating method of the present invention as follows.

First, in order to form a Zn and Ni multilayer plating film, 200 ml of a sulfuric acid-based Zn-Ni alloy plating solution was prepared and then plating was performed.

ZnSO ₄ -7H ₂ O: 46.0 g

NiSO ₄ -6H ₂ O: 4.20 g

H ₂ SO ₄ : 4 ml

HCl: 0.03ml

POELE: 0.8g

As shown in FIG. 13, a Zn-rich layer having a thickness of 6 μm and a Ni-rich layer having a thickness of 3 μm were alternately plated with 20 layers each. The plating conditions at this time were -1.8V plating voltage, -250mA/cm ² current density, and 10 minutes plating time in the first application period, and -1.2V plating voltage and -1.2V current density in the second application period. 100 mA/cm ² , and the plating time was 10 minutes. The first and second application periods were repeated 20 times each (20 cycles) and tested.

Moreover, although not shown in the drawing, when the plating current or plating time is increased using the same plating solution, the Zn-rich layer and the Ni-rich layer are alternately plated thicker.

In addition, when a third metal salt is further added to the plating solution of [Examples 1, 2, and 3] and the reduction potential of the metal salt is applied, the third metal is precipitated and the first plating layer, the second plating layer, and the third plating layer are alternately formed. It is possible to form a multi-layer plating film laminated with. A cross-sectional view of the plating layer formed at this time is shown in FIG. 14, and a structure in which multi-layer thin film layers composed of a first plating layer 42, a second plating layer 43, and a third plating layer 44 are alternately stacked on a base material 41 can be confirmed. can

15 is a graph showing conditions in which an oxide film of a material to be joined is removed, that is, reduced, in order to explain a method of bonding at a low temperature using a low-temperature sintered bonding material using a plating method according to the present invention. In metal soldering and brazing bonding, an oxide layer on the surface of a material to be joined greatly deteriorates bonding. Since general metals other than noble metals such as gold form a surface oxide layer in an atmosphere of room temperature in the air, in order to achieve good bonding, the surface oxide layer must be removed by adjusting the temperature and bonding atmosphere. The low-temperature sintering bonding material bonding medium prepared in the present invention is unstable because the grain size of the laminated plating layer is small, the surface energy of the particles is large, and the surface area between nanometer-thick plating layers is increased, and sintering easily occurs at low temperature through this. allows the bonding of At this time, good bonding is achieved at a temperature equal to or higher than the temperature at which the oxide film on the surface of the material to be joined in FIG. 15 is removed.

In the graph of FIG. 15, the X-axis represents the temperature, the left Y-axis represents the dew point temperature in an atmosphere containing hydrogen during bonding, and the right Y-axis represents the degree of vacuum or partial pressure of water vapor in a vacuum atmosphere during bonding. In the figure, the upper part of each curve is stable in the oxidized state of the metal, and the lower part of the curve is stable in the reduced state of the metal. In order for the material to be joined to be brazed or soldered, the temperature and atmosphere of the reduction region falling below the oxide curve of FIG. 15 are necessarily required. Atmospheres can also be created using chemicals that remove oxides (brazing, soldering fluxes) if present.

For example, all stainless steels contain chromium, and since the chromium oxide film among stainless steel components is strong, the chromium oxide film must be reduced to chromium in order to join stainless steel. That is, maintaining the temperature and atmosphere below the chromium oxide (Cr ₂ O ₃ ) curve indicated by number 1 in FIG. 15 is absolutely necessary for brazing and soldering of stainless steel. For example, chromium oxide (Cr ₂ O ₃ ) on the surface is reduced to chromium at a temperature of 800 ° C or higher when the bonding atmosphere is maintained at 10 ^-2 torr, and at a temperature of 600 ° C or higher when maintained at 10 ^-3 torr. This makes it possible to join stainless steel. In addition, when maintaining 10 ^-5 torr, chromium oxide (Cr ₂ O ₃ ) on the surface does not exist at a temperature of 500 ° C or higher, so that stainless steel bonding is also possible. In the case of bonding in a reducing gas atmosphere including hydrogen, the dew point of the left Y-axis may be used as a standard instead of the degree of vacuum.

However, in general, when Ni-Cu-based alloy (bulk material) is used as a bonding medium to join stainless steel, the melting point increases as Ni increases, so the lowest melting temperature is when 100%Cu-0%Ni ( 1083 ° C, which is practically the melting point of Cu). Therefore, a typical bonding temperature using a Ni-Cu-based bulk alloy as a bonding medium (eg, a brazing temperature of a Ni-Cu-based bulk alloy or stainless steel using Cu or Ni as a bonding medium) is about 1200° C. or higher.

On the other hand, when the Ni-Cu low-temperature sintering joint material prepared by the manufacturing method of the present invention is used as a bonding medium, the interfacial energy is high and the surface area between the plating layers is large due to the small particles with a large specific surface area, so it is unstable, and an exothermic reaction occurs during heating. do. At this time, the Ni-Cu low-temperature sintering joint material is sintered at a low temperature using the exothermic reaction, and as shown in Example 4, stainless steel can be sintered and joined at a temperature of 900 ° C or lower. In addition, bonding is possible at 800 ° C, 700 ° C or lower depending on the plating conditions of the low-temperature sintered joining material. Therefore, it can be seen that the content of the graph of FIG. 15 that bonding is possible in the reduction region where the surface oxide of the material to be joined is removed is consistent.

When using the Ni-Cu low-temperature sintered joint material of the present invention as a bonding medium, the bonding temperature is 200 ~ 600 ℃ lower than the bonding temperature (1200 ℃) of stainless steel of the existing general bulk material Ni-Cu-based bonding medium alloy In terms of percentage, it is only 50 to 83% of the existing junction temperature. Therefore, the energy saving rate of the bonding method using the Ni-Cu low-temperature sintering bonding material is 17 to 50%. Of course, a similar effect can be obtained in general carbon steel that does not contain chromium (in FIG. 14, FeO is located in the upper left corner than Cr ₂ O ₃ ).

[Example 4]

The Ni-Cu bonding material developed in the present invention diffuses between the laminated plating layers at a low temperature, generates heat, and when measured by DTA, has a lower melting point than Cu (melting point 1083°C) and Ni (melting point 1445°C), which are elements constituting the plating layer. A peak appears at 567 ° C, and the Ni-Cu bonding material melts. At this time, the thermal characteristics of the Ni-Cu bonding material were measured by DTA and shown in FIG. The peak in FIG. 16 corresponds to about 52.3% of 1083 ° C, which is the lowest melting point of the Ni-Cu-based alloy. Through this result, the melting point is lower than that of Cu (melting point 1083℃) and Ni (melting point 1445℃), which are elements constituting the plating layer using the Ni-Cu bonding material as a bonding medium, and lower than the lowest melting point of 1083℃ of Ni-Cu-based bulk alloy. 304 stainless steel was cold-joined at low temperatures of 600°C, 700°C, 800°C, 900°C, and 1000°C. Due to the effect of the exothermic reaction of the multi-layer metal plating thin film, the multi-layer metal plating thin film is sintered at a temperature lower than the melting point of Cu (melting point 1083 ° C) and Ni (melting point 1445 ° C) and the lowest melting point of these bulk alloys, resulting in low-temperature bonding.

In detail, a Ni-Cu low-temperature sintered joint material was formed on a 304 stainless steel plate having a size of 30 X 10 X 0.3 (mm). The stainless steel specimen with the low-temperature sintered joint material was overlapped facing the unplated stainless steel specimen and bonded at 600 ° C, 700 ° C, 800 ° C, 900 ° C, 1000 ° C for 10 minutes using a vacuum furnace of 10 ^-4 torr. , and the results are shown in FIG. 17 . A tensile test was performed on the stainless steel specimens bonded at 900 ° C. As a result, the tensile strength reached 117 kgf.

The fracture surface of the junction at this time is shown in FIG. 18, and it can be confirmed that the multilayer plated thin film was well joined.

On the other hand, in the case of iron oxide (FeO) indicated by number 2 in FIG. 15, it is present in the upper left of the figure and is much easier to reduce than chromium oxide. That is, as shown in the graph, at a vacuum degree of about 50 torr, FeO is reduced to Fe metal at a temperature of 100 ° C or higher, and good low-temperature bonding can be achieved. In addition, at a high vacuum degree of 10 ⁻³ torr or less, Fe exists even at a temperature of 100° C. or less, so that good low-temperature bonding can be achieved.

In addition, the metal group Au, Pt, Ag, Pd, Ir, Cu, Pb, Co, Ni, Sn, Os, and Bi shown in No. 3 in FIG. 15 are present in the upper left than FeO shown in the graph, and have an oxide film than FeO. Since it is easier to remove, it can be seen that bonding is possible even at a temperature lower than the condition in which FeO is reduced (eg, 100 ° C. or less) or in a worse vacuum and reducing atmosphere.

On the other hand, the lowest melting point of Sn-Cu-based alloy (bulk material) is 227 ℃ (called eutectic temperature) when the composition is 99.3%Sn-0.7%Cu, When using Sn-Cu-based alloy as a bonding medium, the bonding (soldering) temperature is about 260 to 270 ℃, which is about 40 ℃ higher than the melting point. For example, when electronic components are soldered with a 99.3%Sn-0.7%Cu solder material, the soldering (soldering) temperature is about 260 to 270°C.

On the other hand, when the Sn-Cu low-temperature sintering bonding material developed in the present invention is used as a bonding medium, the low-temperature sintering bonding material has a high interfacial energy due to its small particle size, is unstable due to the large surface area of the plating layer, and densification and An exothermic reaction occurs due to the growth of crystal grains inside the plating layer (see Example 5). At this time, the Sn-Cu low-temperature sintered joint material is sintered at a low temperature using the exothermic reaction, and as shown in Example 5, the melting point is lower than Sn (melting point 232 ℃) and Cu (melting point 1083 ℃), which are elements constituting the plating layer, and Sn -Copper can be bonded at a low temperature of 160, 170, 210℃, which is lower than the lowest melting point of Cu-based bulk alloy, 227℃. Therefore, compared to the bonding temperature (260 ~ 270 ℃) using Sn-Cu-based alloy of conventional bulk materials as a bonding medium (solder), the Sn-Cu low-temperature sintered bonding material produced by the present invention is used as a bonding medium. In this case, the junction temperature is 50~110℃ lower, and the percentage is only 59~81% compared to the existing junction temperature. As a result, the energy saving rate of the bonding method using the Sn-Cu low-temperature sintering bonding material is 19 to 41% compared to the existing Sn-Cu solder.

[Example 5]

The Sn-Cu low-temperature sintered joint material developed in the present invention diffuses at a low temperature and generates heat, and when measured by DSC, a peak appears at 144 ° C., and the Sn-Cu low-temperature sintered joint material melts. Thermal characteristics at this time were measured by DSC and are shown in FIG. 19 . The peak in FIG. 19 corresponds to about 63.4% of 227° C., which is the lowest melting point (eutectic temperature) of the Sn-Cu-based alloy. Through the results of FIG. 19, the copper plates were low-temperature joined at 160 ° C, 170 ° C, and 210 ° C using the Sn-Cu low-temperature sintered bonding material as a bonding medium. In detail, a Sn-Cu low-temperature sintered joint material was formed on a Cu plate having a size of 30 X 10 X 0.3 (mm). At this time, a photograph of the Sn-Cu low-temperature sintering bonding material is shown in FIG. 20. Cu specimens having Sn-Cu low-temperature sintered bonding materials were overlapped with the plating layers facing each other and bonded at a temperature of 160 ℃, 170 ℃, 210 ℃ in the air or in a vacuum furnace of 10 ^-3 torr for 10 minutes. A photograph of the bonding at this time is shown in FIG. 21 . As a result of the tensile test of the bonded specimen at 170 ℃, the tensile strength reached 38kgf.

In Example 5 of the present invention, copper was bonded at a temperature of 160° C. or higher in the air or in a vacuum furnace of 10 ^-3 torr, and in Example 4, stainless steel was bonded at a temperature of 600° C. or higher in a vacuum furnace of 10 ^-4 torr. . These bonding examples are shown in FIG. 15 . As a result, it can be seen that if the low-temperature sintering bonding material manufactured by the present invention is used as a bonding medium, low-temperature bonding is possible under the condition of a temperature equal to or higher than the corresponding temperature in the region where the material to be joined is reduced. Of course, the highest bonding temperature is below the melting point of the material to be joined.

As another embodiment, a multilayer nano-thin film exhibiting Cu-Ag exothermic and amorphous characteristics was prepared by the method of the present invention, and the thermal characteristics at this time were measured by DTA and are shown in FIG. 22 . At this time, due to the exothermic characteristics, a peak appears at 678.54 ° C, which is lower in melting point than Ag (melting point 961 ° C) and Cu (melting point 1083 ° C), which are elements constituting the plating layer, which is the lowest melting point of Cu-Ag-based bulk alloy (process ( It corresponds to about 87.1% of 779℃, which is the eutectic temperature, Cu-40%Ag).

From the above thermal characteristics test examples, the low-temperature sintering joint material prepared through the present invention has a melting point of the existing joint medium alloy in bulk form of 52.3% (Ni-Cu multilayer thin film) or more 87.1% (Cu-Ag multilayer thin film) A peak appeared in the temperature range below, and even in this temperature range, where bonding (brazing, soldering) is impossible because the existing bonding medium does not melt, the bonding medium is melted by an exothermic reaction and bonding (brazing) , soldering) is possible. In addition, naturally, bonding is possible even at a temperature of 87.1% or higher if the medium of the present invention is used, and the upper limit temperature for bonding is a range below the melting point of the existing bonding medium or the melting point of the material to be joined.

The low-temperature sintered joint material of the present invention exists in a layered structure in a plated state, but when used as a bonding medium for low-temperature bonding, when heated, the first and second plating layers of the low-temperature sintered joint material disappear by sintering to form a joint to increase bonding strength. In fact, it was confirmed that the Sn-Cu-based multi-layer nano-thin film layer having exothermic properties was formed and heated at 160° C. to disappear the multi-layer nano-thin film layer. At this time, the disappearance of the first and second plating layers of the Sn-Cu low-temperature sintered bonding material before heating and the disappearance of the first and second plating layers after heating is shown in FIG. 23 .

In addition, it was confirmed that a Ni-Cu low-temperature sintered bonding material was formed and heated at 650 ° C. to disappear the multi-layered nano-thin film layer. 24 shows the first and second plating layers of the Ni-Cu-based multilayer nano-thin film layer before heating, and the disappearance of the first and second plating layers due to diffusion after heating.

In addition, the phase was analyzed using XRD to confirm the crystalline characteristics of the low-temperature sintered joint material. 25 shows XRD analysis of the Sn-Cu low-temperature sintered joint material prepared by the manufacturing method of the low-temperature sintered joint material according to the present invention before heat treatment and after heat treatment at 250 ° C for 30 minutes, crystallinity due to increase in particle size after heating Graph (a) showing this increased characteristic, and XRD analysis of the Ni-Cu low-temperature sintered joint material before heat treatment and after heat treatment at 800 ° C for 30 minutes, a graph showing the increased crystallinity due to the increase in particle size after heating (a) is shown.

In Tables 1 and 2, the results of calculating the particle size through XRD analysis before heat treatment of the Sn-Cu low temperature sintered joint material prepared by the manufacturing method of the low temperature sintered joint material according to the present invention and after heat treatment at 250 ° C for 30 minutes Table 3 and Table 4 show the particle size of the Ni-Cu low-temperature sintered joint material prepared by the manufacturing method of the low-temperature sintered joint material according to the present invention before heat treatment and after heat treatment at 800 ° C. for 30 minutes through XRD analysis The result of calculating is shown.

Before Cu/Sn heat treatment peak 2-theta
(deg) lattice constant
(A) Height
(CPS) FWHM
(deg) Size calculation
(A) Cu/Sn(112) 30.068 2.9696 5647 0.22 689 Sn(200) 30.566 2.9223 829 0.195 737 Sn(101) 31.955 2.7984 10669 0.146 987 Cu/Sn(202) 35.146 2.5513 269 0.211 689 Cu/Sn(410) 42.923 2.1054 5713 0.307 485 Cu(111) 43.239 2.0907 3312 0.203 734 Sn(220) 43.828 2.064 1670 0.163 917 Sn(211) 44.835 2.0199 17308 0.158 949 Cu(200) 50.388 1.8096 15981 0.188 815 Cu/Sn(325) 53.335 1.7163 1126 0.318 488 Sn(304) 55.262 1.6609 599 0.178 879 Cu/Sn(034) 56.666 1.6231 232 0.203 776 Cu/Sn(511) 59.973 1.5412 234 0.252 635 Sn(112) 62.46 1.4857 2077 0.228 711 Sn(321) 64.525 1.443 4607 0.158 1037 Cu/Sn(351) 70.743 1.3307 448 0.208 817 Sn(420) 72.382 1.3045 338 0.16 1073 Cu(220) 74.072 1.2789 5690 0.16 1085 Sn(312) 79.436 1.2055 1504 0.172 1048

After Cu/Sn heat treatment peak 2-theta
(deg) lattice constant
(A) Height
(CPS) FWHM
(deg) Size calculation
(A) Cu/Sn(112) 29.995 2.9767 31244 0.152 944 Cu/Sn(202) 35.036 2.5591 4527 0.122 1191 Cu/Sn(104) 37.364 2.4048 2201 0.221 662 Cu/Sn(023) 39.513 2.2788 912 0.118 1248 Cu/Sn(002) 41.594 2.1695 1309 0.124 1196 Cu/Sn(2,10,1) 43.142 2.0952 34299 0.169 882 Cu(200) 50.349 1.8109 2371 0.118 1298 Cu/Sn(325) 53.213 1.7199 791 0.145 1069 Cu/Sn(202) 54.062 1.6949 478 0.12 1297 Cu/Sn(034) 56.564 1.6257 1384 0.201 783 Cu/Sn(511) 59.866 1.5437 4641 0.178 899 Cu/Sn(622) 62.478 1.4853 4039 0.219 740 Cu/Sn(0,10,3) 67.732 1.3823 6941 0.138 1210 Cu(220) 74.18 1.2773 1690 0.208 835

Before Cu/Ni heat treatment peak 2-theta
(deg) lattice constant
(A) Height
(CPS) FWHM
(deg) Size calculation
(A) Cu(111) 43.247 2.0903 4868 0.193 815 Ni/Cu(111) 44.231 2.0461 4105 0.841 188 Cu(200) 50.358 1.8106 39906 0.201 804 Cu(220) 74.022 1.2796 9449 0.305 601 Ni/Cu(220) 76.483 1.2445 15428 1.005 185

After Cu/Ni heat treatment peak 2-theta
(deg) lattice constant
(A) Height
(CPS) FWHM
(deg) Size calculation
(A) Ni/Cu(111) 44.111 2.0514 119434 0.366 431 Ni/Cu(200) 50.415 1.8086 3371 0.51 317 Cu(220) 74.11 1.2783 2210 0.506 362 Ni/Cu(220) 75.268 1.2615 1820 0.487 379

[Comparative Example 1] Multilayer metal material without exothermic reaction

When the thickness of each layer of the multi-layer metal plating layer increases or the number of plating layers decreases, the area of the interface in the multi-layer metal plating layer decreases. In this embodiment, a Sn-Cu-based bonding material made thick so that the sum of the thicknesses of the two layers is 5 μm was manufactured so as not to have an exothermic reaction. At this time, the cross-section of the Sn-Cu multilayer material manufactured with the sum of the thicknesses of the two layers being 5 μm was confirmed with an electron microscope and shown in FIG. 26. In addition, the thermal characteristics of this multilayer material were measured by DTA and shown in FIG. 27 . As a result, a low-temperature exothermic peak did not appear in the DSC measurement, and an endothermic peak appeared at 228° C., which is the temperature at which tin, an element constituting the plating, melts at high temperatures. That is, the exothermic peak at 144 ° C, which appeared in the Sn-Cu-based bonding material manufactured as thin as the sum of the two layers of 40 nm, did not appear in the material manufactured as thick as 5 μm.

In order not to have an exothermic reaction at this time, the semiconductor was heated to a copper electrode at a temperature of 170° C. using a material in which each plating layer was thick. As a result of observing the junction between the semiconductor and the electrode at this time with an optical microscope, it was not joined, and the results are shown in FIG. 28 . As a result of thermal analysis, the bonding material in which each plating layer was manufactured to be thick showed only an endothermic peak, and since the endothermic value is greater than the calorific value, it can be judged that it is not bonded.

In addition, a Sn-Cu-based multi-layer metal plating thin film made of six plating layers was manufactured and the copper electrode was low-temperature bonded at 160 ° C., and a cross section at this time is shown in FIG. 29. The joints at this time were partially joined. This is because the calorific value was not sufficient due to the small number of plating layers and the amount of molten metal was not sufficient.

In addition, by lengthening the plating time, a Sn-Cu-based multilayer metal plating thin film having a total plating thickness of 300 μm was prepared, and a cross section at this time is shown in FIG. 30. In the multi-layer metal thin film manufactured through the present invention, defects may occur on the surface of the plating layer as plating progresses, and the defect continues to grow in a vertical plane. The plating layer is not well formed, amorphous and heat-generating characteristics are not shown, and low-temperature bonding is not performed.

As described above, although the present invention has been described by the limited embodiments and drawings, the present invention is not limited to the above embodiments, and those skilled in the art in the field to which the present invention belongs can make various modifications and variations from these descriptions. this is possible

Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, and should be defined by not only the claims to be described later, but also those equivalent to these claims.

10: Low-temperature sintering joint material manufacturing device
11: Courage
12: reference electrode
13: anode
14: cathode
16: magnetic for stirring
20: PC
30: low temperature sintering joint material
31: conductive substrate
32: insulating tape
33: first plating layer
34: second plating layer
41: plated substrate
42: first plating layer
43: second plating layer
44: third plating layer

Claims (21)

delete delete delete delete delete delete delete delete delete delete delete delete delete A bonding material in which at least one or more metals are electroplated and laminated, includes a metal plating film having a grain size of 10 nm to 150 nm, and is sintered when heated to join materials to be joined,
The metal plating film generates an exothermic reaction during sintering, and a melting temperature (T _s2 ) when reheating after the sintering is higher than the sintering temperature (T _s1 ).
According to claim 14,
The metal plating film is a low-temperature sintering bonding material comprising a first plating layer and a second plating layer in which at least two or more metals are electroplated and laminated and have a grain size of 10 nm to 150 nm.
According to claim 14,
The metal is Sn, Cu, Zn, Ni, Al, Ti, V, Cr, Mn, Fe, Co, Ga, Ge, As, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sb , Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, and at least one metal selected from the group consisting of Bi, a low-temperature sintered joint material.
According to claim 15,
When the metal is in a metal salt state, a low-temperature sintering joint material using two or more selected metals having a standard reduction potential difference of 0.029V or more and 1.0496V or less.
According to claim 14,
The thickness of the entire metal plating film is 0.6nm to 300㎛ low-temperature sintering bonding material.
According to claim 15,
The metal plating film is a low-temperature sintering bonding material made of a structure in which the first plating layer and the second plating layer are repeatedly laminated 6 times or more.
According to claim 14,
The temperature at which the metal plating film is sintered (T _s1 ) is lower than the melting point (T _ma ) of the entire bulk composition constituting the metal plating film.
According to claim 14,
The low-temperature sintering joining material is a low-temperature sintering joining material for joining materials to be joined by an exothermic reaction caused by densification and crystal grain growth of the metal plating film.

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