KR20220135456A - Method of manufacturing core-shell type particle and core-shell type particle produced therefrom - Google Patents

Abstract

Disclosed in the present invention are a method of manufacturing core-shell type powder and core-shell type powder manufactured thereby, wherein the method includes a step (A) of disposing a metal seed layer on the surface of a core by dry sputtering, and a step (B) of disposing a plating layer on the surface of the metal seed layer by electroless plating. The method of manufacturing core-shell type powder according to the present invention can reduce manufacturing costs and minimize the production of contaminative waste water by not using pretreatment for improving plating activation.

Description

Method of manufacturing core-shell powder and core-shell powder manufactured thereby

The present invention relates to a method for producing a core-shell powder and to a core-shell powder produced thereby.

Recently, as the 'light, thin, and compact' of information and communication devices is rapidly progressing, the speed of change in internal parts and materials is also rapidly progressing. Due to this phenomenon, the use of conductive adhesives is increasing in the semiconductor material packaging process, and various substitutes for performance improvement and cost reduction of core-shell powder of Au-Ni-Polymer or Ni-Polymer structure, which are mainly used. development is in progress.

In particular, metal particles are used as a bonding material for mounting small electronic components such as semiconductor chips or resistance chips on PCBs. In recent years, along with the miniaturization of integrated circuits, the size or spacing of pads tends to be reduced and the number of pads tends to increase, and accordingly, device defects due to unnecessary electrical connection are increasing. In addition, recent electronic packaging, especially semiconductor package stacked POP (Package on Package), WLP (Wafer Level Package), TSV (Through Silicon Via), CSP (Chip Scale Package), Chip stack package, LCD, COG (Chip on Glass), In COF (Chip on Film), the need to connect a large number of electrodes with narrow gaps at once is gradually increasing according to the fine gap of the circuit and the increase in the connection density.

For this purpose, studies on metal balls or conductive conductive films having excellent electrical conductivity are being actively conducted. The metal ball is formed by coating a conductive metal or metal compound on the surface of the substrate particle, and the conductive film includes conductive particles and an insulating adhesive, and the conductive particles include tin, copper, aluminum, nickel, Alternatively, a metal ball coated with silver or the like is mainly used.

Conventional conductive metal balls having conductive or bonding properties are generally manufactured by forming a metal coating layer on the surface of a substrate particle through a plating process. That is, in the prior art, a conductive metal ball was manufactured by coating a metal on the surface of a substrate particle of a conductive metal, such as Cu or Al, or a substrate particle, such as a plastic ball, using a plating process.

In particular, the conventional metal ball may be formed by coating a plurality of metal layers on the surface of the substrate particles, and 5 or more metal layers may be coated depending on the laminated structure. In this case, the conventional metal ball may be manufactured through a plating process of 5 or more times to form different metal layers according to the stacked structure of a plurality of metal layers. As a result, since the conventional process for manufacturing a metal ball requires a repetitive wet process, time, effort, and cost for manufacturing the metal ball are increased, thereby reducing productivity.

The present invention is a plating method that does not use an expensive palladium catalyst during wet plating and does not use a pretreatment process to improve plating activity during plating. An object of the present invention is to provide a manufacturing method and a core-shell type powder prepared thereby.

On the other hand, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned are clearly to those of ordinary skill in the art to which the present invention belongs from the description below. can be understood

A method of manufacturing a core-shell powder according to an embodiment of the present invention includes the steps of (A) disposing a metal seed layer on the surface of a core by dry sputtering; and (B) disposing a plating layer on the surface of the metal seed layer by electroless plating.

In addition, (C) surface treatment of the surface of the plating layer with a metal salt fatty acid; (D) washing the surface of the surface-treated plating layer: and (E) drying and heat-treating the washed core-shell powder.

In addition, the step (A) may include (A-1) disposing a bonding layer on the surface of the core, and (A-2) disposing a conductive layer on the surface of the bonding layer.

In addition, in step (A), the bonding layer may include a first metal, the conductive layer may include a second metal, and the first metal and the second metal may be different.

In addition, the metal salt fatty acid may be one selected from the group consisting of potassium stearate, sodium stearate, and zinc stearate.

On the other hand, the core-shell powder according to an embodiment of the present invention includes a core; a metal seed layer disposed on the surface; and a plating layer disposed on a surface of the metal seed layer.

The metal seed layer may include disposing a bonding layer disposed on the surface of the core and a conductive layer disposed on the surface of the bonding layer.

In addition, the bonding layer may include a first metal, the conductive layer may include a second metal, and the first metal and the second metal may be different from each other.

In addition, the thickness of the bonding layer may be less than or equal to the thickness of the conductive layer.

In addition, the thickness of the bonding layer is 0.1 nm to 50 nm, the thickness of the bonding layer is 0.1 nm to 50 nm, a thickness ratio of the bonding layer and the metal seed layer is 1:2 to 1:10, and the metal seed The thickness ratio of the layer and the plating layer may be 1:1 to 1:20.

According to an embodiment of the present invention, it is a plating method that does not use an expensive palladium catalyst during wet plating and does not use a pretreatment process to improve plating activity during plating. It is possible.

On the other hand, the effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. will be able

1 is a flowchart sequentially showing a method for manufacturing a core-shell type powder according to an embodiment of the present invention; Figure 2 is a subdivided flow chart of the metal seed layer arrangement step in the method for producing a core-shell-type powder according to an embodiment of the present invention; 3 is a cross-sectional view schematically illustrating a core-shell-type powder manufactured by a method for manufacturing a core-shell-type powder according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to the accompanying drawings. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the following embodiments. This embodiment is provided to more completely explain the present invention to those of ordinary skill in the art. Accordingly, the shapes of elements in the drawings are exaggerated to emphasize a clearer description.

The configuration of the invention for clarifying the solution to the problem to be solved by the present invention will be described in detail with reference to the accompanying drawings based on a preferred embodiment of the present invention, but the same in assigning reference numbers to the components of the drawings For the components, even if they are on different drawings, the same reference numbers are given, and it is noted in advance that the components of other drawings can be cited when necessary in the description of the drawings.

1 is a flowchart sequentially showing a method of manufacturing a core-shell type powder according to an embodiment of the present invention, and FIG. 2 is a method for manufacturing a core-shell type powder according to an embodiment of the present invention. It is a flowchart, and FIG. 3 is a cross-sectional view schematically showing a core-shell type powder manufactured by a method for manufacturing a core-shell type powder according to an embodiment of the present invention.

1 to 3 , the method for manufacturing a core-shell powder according to an embodiment of the present invention includes a core preparation step (S10), a metal seed layer arrangement step (S20), a plating layer arrangement step (S30), a surface treatment step (S40) and a heat treatment step (S50) may be included.

In the core preparation step ( S10 ), the core 110 is prepared by measuring the raw material and loading it at a level corresponding to 10 to 20 vol% of the area of the barrel in the chamber.

The core 110 is preferably configured in a spherical shape, but the present invention is not limited thereto as it may be configured in various shapes.

Here, the raw material of the core may be composed of at least one selected from the group consisting of lightweight hollow graphene or carbon-based powder such as graphite, or hollow silica (SiC) or glass powder (Glass beed).

On the other hand, in the core preparation step (S10), for an excellent dispersion effect of the raw material, a dispersion medium may be added, and the medium may be charged at 5 to 15 vol% of the area of the barrel.

Here, the type of the medium is not limited, but it is preferable to use a material 2 to 4 times higher than the density of the above-mentioned raw material. In the present invention, it is possible to use the stainless steel powder or the gold steel powder, or a mixture of the stainless steel powder and the gold wire powder.

In the step of disposing the metal seed layer ( S20 ), the metal seed layer 120 may be disposed on the surface of the prepared core 10 through dry sputtering.

Here, in the dry sputtering process, a metered metal seed layer raw material is charged into a rotating barrel, an inert gas (eg, argon) is injected and the barrel is rotated in an atmosphere in which plasma is generated, and the target of the metal to be coated (Target) ), ions are eluted and settled on the surface of the base material (core).

) 단위의 금속이온이 모재에 안착되어 우수한 막 치밀도를 형성하게 되며, 모재와의 밀착력이 향상될 수 있다.A material of the target of the metal seed layer 120 may include gold (Au), silver (Ag), copper (Cu), nickel (Ni), or the like. A thickness (T1) of the metal seed layer 120 layer may be in a range of 0.2 nm to 300 nm. Angstrom

) unit is seated on the base material to form an excellent film density, and adhesion with the base material can be improved.

Meanwhile, the metal seed layer arrangement step ( S20 ) may include a bonding layer arrangement step ( S21 ) and a metal layer arrangement step ( S22 ).

In the bonding layer arrangement step S21 , the bonding layer 121 may be disposed on the surface of the prepared core 10 , and in the metal layer arrangement step S22 , the metal layer 122 may be disposed on the surface of the bonding layer 121 .

That is, the metal seed layer 120 may include a bonding layer 121 and a metal layer 122 .

Specifically, in the bonding layer arrangement step ( S21 ), the bonding layer 121 may be disposed on the surface of the core 110 .

The bonding layer 121 may improve bonding strength between the core 110 and the metal layer 122 , and the bonding layer 121 may include titanium (Ti), chromium (Cr), vanadium (V), nickel-chromium (Ni). -Cr), nickel-vanadium (Ni-V), and copper-chromium (Cu-Cr) may be disposed on the surface of the core 110 through a sputtering process.

Meanwhile, the thickness T2 of the bonding layer 121 preferably ranges from 0.1 nm to 50 nm.

Here, when the thickness (T2) of the bonding layer 121 is less than 0.1 nm, the bonding force between the core 110 and the metal layer 122 is weak, and a problem that can easily fall off may occur, and the thickness of the bonding layer 121 ( If T2) is more than 50 nm, the bonding strength may be improved, but there may be a problem in that the material cost increases due to excessive waste of material.

In the metal layer arrangement step S22 , the metal layer 122 may be disposed on the surface of the bonding layer 121 .

The metal layer 122 uses a conductive metal as a raw material, and at least one selected from the group consisting of gold, silver, copper, and nickel may be disposed on the surface of the bonding layer 121 through a sputtering process.

Meanwhile, the thickness T3 of the metal layer 122 preferably ranges from 0.1 nm to 250 nm. Here, when the thickness T3 of the metal layer 122 is less than 0.1 nm, the reduction reactivity of the conductive metal ions during wet plating in the subsequent process is weak, so it is difficult to form the uniform metal layer 122, and conversely, the thickness of the metal layer 122 When (T2) is greater than 250 nm, the reactivity during wet plating is excellent, but cracks and uniformity of the surface of the metal layer 122 may be poor, and the material cost increases due to excessive material waste.

In addition, a ratio of the thickness T2 of the bonding layer 121 to the thickness T3 of the metal layer 122 may be 1:1 to 1:5.

The total thickness of the metal seed layer 120 may be in the range of 0.1 nm to 300 nm by adding the thickness of the bonding layer 121 and the metal layer 122 .

Here, the ratio of the thickness T2 of the bonding layer 121 to the thickness T1 of the metal seed layer 120 may be 1:2 to 1:10.

In order to form such a metal seed layer 120, the parameters of the sputtering equipment were set as follows.

The vacuum degree is 5.5x10 ^-3 ~ 5.5x10 ^-5 torr, and Ar gas is used as the active gas, the output of the target is 1.2~3kW, and the rotation speed of the barrel is preferably 0.5~5rpm do.

In the plating layer arrangement step S30 , the plating layer 130 may be disposed on the surface of the metal seed layer 120 using wet electroless plating.

Here, the ratio of the thickness T1 of the metal seed layer 120 to the thickness T4 of the plating layer 130 may be 1:1 to 1:20.

On the other hand, since the metal seed layer 120 increases the activity of the plating layer 130 to remove a separate activation process or a catalyst process, the higher the electromotive force, the better the plating activity. can be expressed.

Here, in the plating layer arrangement step ( S30 ), excellent electrical conductivity is realized by increasing the thickness of the conductive metal layers 122 and 130 based on the metal seed layer 120 formed by the dry sputtering process.

Through this, the electrical conductivity can be improved by increasing the thickness of the same material, and the thickness can be increased by a wet process that is cheaper than the expensive sputtering process, thereby lowering the process cost.

In addition, the sputtering process is a coating in angstroms, and when the coating thickness is increased, the non-uniformity and crack occurrence of the coating layer increase, and there is a problem that the defect rate is improved. can improve

Meanwhile, a boundary between the seed layer 120 and the plating layer 130 may exist because the size of the nuclear particles coated in the seed layer 120 formed by sputtering and the plating layer 130 formed by the wet process are different.

Specifically, in the wet electroless plating method, nano-scale nuclear precipitation and coating are formed, and the sputtering process is an angstrom-unit coating, so it can be distinguished by measuring the cross section, but due to this interface, the seed layer 120 and the plating layer 130 ), there is no problem that the adhesion between them is lowered.

Meanwhile, in the above description, the seed layer 120 and the plating layer 130 are made of the same type of metal. It can be formed by a combination of metals of

In the conventional wet electroless plating process, there is a pretreatment process that increases the binding force of the catalyst by lifting the positive charge on the surface of the base material, then settles the catalyst and increases the activity of the catalyst, but in the embodiment of the present invention, the pretreatment process can be removed Thus, it is possible to form a metal plating layer immediately after the dry sputtering process.

That is, the embodiment according to the present invention can reduce the generation of a large amount of environmental wastewater by removing the pretreatment process, and can also obtain the effect of reducing the manufacturing cost due to the insolubility of the expensive catalyst.

In addition, in the embodiment according to the present invention, wet electroless plating is performed in an acidic atmosphere, thereby suppressing a problem caused by agglomeration of particles caused by an alkali base. Here, the electroless plating method is based on an acidic plating method of pH 1 to 2, and plating may be performed by adding a metal compound to a required plating thickness.

In the surface treatment step (S40), the surface of the core-shell-type powder 100 formed up to the plating layer 130 may be surface-treated with a metal salt fatty acid.

Through this, it is possible to prevent the manufactured core-shell powder 100 from being oxidized by moisture, and to improve the dispersion effect with the resin when the paste is manufactured through the core-shell powder 100 .

Here, the fatty acid is preferably a stearic acid of a metal salt, and may be composed of at least one selected from potassium stearate, sodium stearate, zinc stearate, and the like.

Thereafter, in the heat treatment step (S50) step, after washing the surface-treated core-shell-type powder 100, drying and heat treatment are performed, wherein the drying is possible in both hot air or vacuum drying, and the heat treatment is performed in a nitrogen atmosphere. desirable. Specifically, the drying temperature is preferably 60 ~ 90 ℃, the heat treatment temperature is preferably 150 ~ 300 ℃.

On the other hand, this set temperature can be optimally changed according to the size of the core-shell type powder 100 and the thickness of the plurality of coating layers.

The above detailed description is illustrative of the present invention. In addition, the above description shows and describes preferred embodiments of the present invention, and the present invention can be used in various other combinations, modifications, and environments. That is, changes or modifications are possible within the scope of the concept of the invention disclosed herein, the scope equivalent to the written disclosure, and/or within the scope of skill or knowledge in the art. The written embodiment describes the best state for implementing the technical idea of the present invention, and various changes required in specific application fields and uses of the present invention are possible. Accordingly, the detailed description of the present invention is not intended to limit the present invention to the disclosed embodiments. Also, the appended claims should be construed to include other embodiments as well.

100: core-shell type powder 110: core 120: metal seed layer 130: plating layer

Claims (10)

(A) disposing a metal seed layer on the surface of the core by dry sputtering; and (B) disposing a plating layer on the surface of the metal seed layer by electroless plating. According to claim 1, (C) surface treatment of the surface of the plating layer with a metal salt fatty acid; (D) washing the surface of the surface-treated plating layer: And (E) drying and heat-treating the washed core-shell powder A method for producing a core-shell powder comprising the steps of: The method of claim 1, wherein step (A) comprises (A-1) disposing a bonding layer on the surface of the core, and (A-2) disposing a conductive layer on the surface of the bonding layer. A method for producing a core-shell powder. According to claim 3, In the step (A), The bonding layer includes a first metal, The conductive layer includes a second metal, The first metal and the second metal are different core-shell powders manufacturing method. The method of claim 2, wherein the metal salt fatty acid is one selected from the group consisting of potassium stearate, sodium stearate, and zinc stearate. a core; a metal seed layer disposed on the surface; and a plating layer disposed on a surface of the metal seed layer. The core-shell powder of claim 6 , wherein the metal seed layer comprises a bonding layer disposed on a surface of the core and a conductive layer disposed on a surface of the bonding layer. The core-shell powder of claim 7 , wherein the bonding layer includes a first metal, the conductive layer includes a second metal, and the first metal and the second metal are different. The core-shell powder of claim 8 , wherein a thickness of the bonding layer is less than or equal to a thickness of the conductive layer. The thickness ratio of claim 8 , wherein the bonding layer has a thickness of 0.1 nm to 50 nm, a thickness ratio of the bonding layer and the metal seed layer is 1:2 to 1:10, and a thickness ratio of the metal seed layer and the plating layer is 1:1 to 1: 20 core-shell powder.

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