KR20230101609A - Fabrication method of conductive particle and conductive particle - Google Patents

Abstract

The present invention relates to a method for manufacturing conductive particles, and more particularly, after forming grooves for forming conductive particles in a mold, a sintering process of heating a plurality of times using different metal powders is performed multiple times to manufacture desired conductive particles. It relates to a manufacturing method of conductive particles that can be made, and to conductive particles manufactured by the manufacturing method.

Description

Manufacturing method of conductive particle and conductive particle {Fabrication method of conductive particle and conductive particle}

The present invention relates to a method for manufacturing conductive particles used in electrical inspection and to conductive particles.

In general, for electronic components such as semiconductor integrated circuits and semiconductor packages, or circuit boards for constituting or mounting these electronic components, it is necessary to inspect electrical characteristics after manufacturing. In order to test the electrical characteristics of the device to be tested, a stable electrical connection between the device to be tested and a test device (test board) must be made, and a connector for electrical connection is used for this purpose. That is, the role of the connector device for electrical connection is to connect the terminal of the device under test and the pad of the test device to each other so that electrical signals can be exchanged in both directions. Such a connector for electrical connection is also called a test socket in that it is used in a test apparatus for testing a device under test and coupled to the device under test.

As a conventional connector for electrical connection, that is, a test socket, anisotropic conductive sheets and pogo pins are generally used. Among them, the anisotropic conductive sheet has a structure in which a conductive part having elasticity is connected to the terminal of the device under test, and the pogo pin is configured to elastically contact the terminal of the device under test by a spring provided therein.

As described above, the conventional anisotropic conductive sheet and the pogo pin have an advantage of buffering mechanical shock that may occur when the device under test and the test device are connected, and are widely used as test sockets.

1 shows an anisotropic conductive sheet as an example of a conventional connector for electrical connection, and FIG. 2 shows a state in which an electrical test is performed using the anisotropic conductive sheet of FIG. 1 .

The anisotropic conductive sheet 100 according to the prior art supports a plurality of conductive parts 110 disposed at a position corresponding to the terminal 131 of the device under test 130, and mutually supports the plurality of conductive parts 110. It includes an insulating support 120 to insulate.

The conductive part 110 has a structure in which conductive particles 111 are arranged in a thickness direction, that is, in a vertical direction, in a base material made of an insulating elastic material such as silicone rubber, and the insulating support part 120 is the conductive part It is made of the same material as the elastic material in 110, for example, silicone rubber.

Before the test is performed, the anisotropic conductive sheet 100 is mounted on the test device 140, and at this time, each conductive part 110 is in contact with the pad 141 of the test device 140. In the non-pressurized state, a plurality of conductive particles 111 are spaced apart from each other in the conductive part 110 in an insulating elastic material.

When the device to be tested 130, which requires testing, descends, and the terminal 131 of the device to be tested 130 presses the conductive part 110 downward, the conductive particles 111 that are spaced apart from each other come into contact with each other. The conductive part 110 becomes electrically conductive, and in this process, the conductive part 110 is elastically compressed and deformed to prevent mechanical shock that may occur when it comes into contact with the terminal 131 of the device under test 130. will be full

In this way, in a state in which the terminal 131 of the device to be tested 130 and the pad 141 of the testing device 140 are electrically connected to each other by the conductive portion 110 of the anisotropic conductive sheet 100, the testing device ( 140), when a predetermined inspection signal is applied from the pad 141, the signal is transferred to the terminal 131 of the device under test 130 via the conductive portion 110 of the anisotropic conductive sheet 100, thereby providing a predetermined electrical test can be performed.

A plurality of conductive particles arranged in such a conductive part usually have an irregular particle shape including a spherical shape and a staphylococcus shape. Such conventional conductive particles do not have a precise shape and do not have a shape and shape desired by a designer, making it difficult to achieve a desired function.

In particular, general methods of manufacturing conductive particles use water spraying, atomizing, electroplating, etc., and the shape and size of conductive particles produced by these processes are very non-uniform, and making the desired shape constant other than spherical The problem is that it's almost impossible.

In this way, when the conductive particles have a spherical or grape-shaped shape, as shown in FIG. 3, the particles are often separated from the conductive portion or electrical connection is poor during the pressing process of the conductive portion. This is because the conductive particles are made of a metal material and thus do not sufficiently secure bonding strength with the silicone rubber constituting the substrate of the anisotropic conductive sheet.

In order to solve this problem, there is disclosed in Japanese Patent Laid-Open No. 2011-150837 a manufacturing technique of conductive particles for producing conductive particles in a shape desired by a designer.

For example, in order to precisely manufacture the plate-shaped (FIG. 3 (a)) or ring-shaped (FIG. 3 (b), (c)) conductive particles as disclosed in FIG. 4 as desired by the designer, the following manufacturing process is performed. going to be using

First, after preparing a predetermined substrate 150 (FIG. 4 (a)), copper foil 151 is formed on the substrate 150 (FIG. 4 (b)), and a dry film 152 is formed on the copper foil 151. is formed (FIG. 4(c)).

Thereafter, a predetermined groove 152a is formed in the dry film 152 through a photoresist process (FIG. 4(d), and after plating a metal 111' inside the predetermined groove (FIG. 4(e)) ), the upper surface of the plating layer is polished to complete the manufacture of the conductive particles 111. (FIG. 4(f)) After that, the dry film is dissolved in order to remove the conductive particles 111 integrated into the dry film from the dry film. By doing so, conductive particles are obtained.

In the manufacturing process of the conductive particles according to the prior art, since the mold for forming the conductive particles is made of a dry film and the dry film must be dissolved and removed to obtain the conductive particles, the dry film must be adhered to the substrate each time. there is In addition, since a predetermined pattern must be formed by using a photoresist process on the dry film contacted on the substrate, there is a disadvantage in that cost is high in the mold manufacturing step. In addition, since the manufacturing method of conductive particles according to the prior art uses a plating process to manufacture the conductive particles, the larger the thickness of the metal particles, the more plating time is required. In addition, since a plating process is used, there is a disadvantage in that the upper surface must be polished through a CMP process to make the thickness of each conductive particle constant after plating. In addition, a method such as dissolution is used to separate the conductive particles from the substrate and the dry film. In this process, since the dry film is not completely dissolved, separation is not easy.

In order to solve these disadvantages of the prior art, Registered Patent No. 2124997 filed and registered by the present applicant is known. In the manufacturing method of conductive particles disclosed in the above registered patent, after preparing a substrate 200 as shown in FIG. 5 (FIG. 5(a)), forming grooves 201 for forming conductive particles on the substrate 200, , (FIG. 5(b)), filling the groove 201 for forming conductive particles with metal powder 111', and applying heat to the metal powder 111' (FIG. 5(c)) to solidify conductive particles After manufacturing (111) (Fig. 5 (d)), a method of separating the conductive particles 111 from the substrate 200 is adopted.

According to this manufacturing method, there is an advantage in that manufacturing time and manufacturing cost are reduced because desired conductive particles can be rapidly manufactured by filling metal powder and heating without using a plating method.

However, according to such a conventional manufacturing method, it is impossible to use different materials for the central and outer parts or specific parts of the conductive particles in one sintering method, so that the conductive particles manufactured with the optimal alloy ratio for each part of the test socket cannot be applied. There is a downside to being

In particular, anisotropic conductivity that requires resistance, current characteristics, and durability because it is impossible to change the material, such as making only a highly conductive material only for the part where conductive particles come into contact with each other, or using only a high hardness material for only the part that is in frequent contact with the device under test. In the case of the sheet, there is a disadvantage of causing a deterioration in quality.

The present invention has been created to solve the above problems, and has a technical object to provide a method for manufacturing conductive particles and conductive particles capable of simply and quickly producing conductive particles having a desired shape and desired characteristics.

The method for manufacturing conductive particles of the present invention for achieving the above technical object is used for an anisotropic conductive sheet for electrical connection between a terminal of a device under test and a pad of a test device, and a plurality of particles are contained in an elastic insulating material and avoid A method of manufacturing conductive particles used to form a conductive path for electrical connection between a terminal and a pad by contacting each other by pressurization of an inspection device,

(a) preparing a mold substrate;

(b) forming a groove for forming conductive particles having a shape corresponding to the conductive particles and opened to one side on either side of the mold substrate;

(c) filling the first metal powder into the grooves for forming the conductive particles;

(d) heating the first metal powder at a temperature lower than the melting point of the first metal powder to prepare solid core particles whose volume is reduced compared to the grooves for forming conductive particles;

(e) filling a second metal powder made of a different material from the first metal powder around the core particle in the groove for forming the conductive particle;

(f) heating the second metal powder at a temperature lower than that of the second metal powder to prepare solidified conductive particles having a volume smaller than that of the grooves for forming conductive particles.

In the method for producing the conductive particles,

After the step (f), a step of separating the conductive particles from the grooves for forming the conductive particles of the mold substrate may be further included.

In the method for producing the conductive particles,

The first metal powder may be made of a material exhibiting magnetism, and the second metal powder may be made of a non-magnetic conductive material.

In the method for producing the conductive particles,

The second metal powder may be made of a material having better conductivity than the first metal powder.

In the method for producing the conductive particles,

The second metal powder may be made of a material exhibiting magnetism, and the first metal powder may be made of a non-magnetic conductive material.

In the method for producing the conductive particles,

The first metal powder may be made of a material having higher conductivity than the second metal powder.

In the method for producing the conductive particles,

The first metal powder is a mixed powder including a magnetic powder exhibiting magnetism and a non-magnetic conductive powder, and the mixed powder may contain the magnetic powder in a higher ratio than the conductive powder.

In the method for producing the conductive particles,

The first metal powder is a mixed powder including a magnetic powder exhibiting magnetism and a non-magnetic conductive powder, and the mixed powder may contain the conductive powder in a higher ratio than the magnetic powder powder.

In the method for producing the conductive particles,

A plurality of pores may be formed inside the conductive particle prepared in step (f).

In the method for producing the conductive particles,

A plurality of pores connected to internal pores may be formed on the outside of the conductive particle prepared in step (f).

In the method for producing the conductive particles,

The heating temperature in step (d) may be higher than the heating temperature in step (f).

In the method for producing the conductive particles,

The melting point of the first metal powder may be equal to or higher than the melting point of the second metal powder.

In the method for producing the conductive particles,

The heating temperature in steps (d) and (f) may be lower than the melting points of the first metal powder and the second metal powder.

The method for producing conductive particles of the present invention for achieving the above technical object is

It is used for the anisotropic conductive sheet for electrical connection between the terminal of the device under test and the pad of the test device, and a plurality of sheets are contained in an elastic insulating material and are in contact with each other by the pressure of the device under test to conduct electrical connection between the terminal and the pad. As a method for producing conductive particles used to form a furnace,

(a) preparing a mold substrate;

(b) forming a groove for forming conductive particles having a shape corresponding to the conductive particles and opened to one side on either side of the mold substrate;

(c) filling the first metal powder into the grooves for forming the conductive particles;

(d) heating the first metal powder at a temperature lower than the melting point of the first metal powder to produce solid first particles whose volume is reduced from that of the grooves for forming conductive particles;

(e) filling a second metal powder made of a different material from the first metal powder around the first particles in the groove for forming the conductive particles;

(f) heating the second metal powder at a temperature lower than that of the second metal powder to produce second particles in which the volume is reduced and solidified than the grooves for forming conductive particles and the first particles are integrally bonded therein; can include

In the method for producing the conductive particles,

After step (f),

Conductive particles may be manufactured by repeating steps (e) and (f) at least once using a different type of metal powder made of a different material from the first metal powder.

Conductive particles of the present invention for achieving the above technical object,

As the conductive particles produced by the above-described manufacturing method,

A core particle made of the first metal powder as a material;

It may include an outer layer made of a second metal powder as a material and surrounding at least a portion of the core particle.

In the conductive particles,

In the conductive particle, a plurality of pores may be formed inside the inner core particle.

In the conductive particles,

The plurality of pores may be connected to the surface of the conductive particles.

In the conductive particles,

The core particle is made of a polyhedron,

The outer skin layer may surround at least two or more surfaces of the core particle.

The conductive particles of the present invention for achieving the above technical object are used in an anisotropic conductive sheet for electrical connection between terminals of a device under test and pads of a test device, and are contained in a plurality of elastic insulating materials and As conductive particles used to form a conductive path for electrical connection between a terminal and a pad by contacting each other by pressing,

Core particles made of a conductive material and solidified by sintering the first metal powder; and

At least a portion of the core particle is surrounded,

It consists of a second metal powder made of a material different from the first metal powder,

It is solidified by sintering the second metal powder and includes an outer layer made of a conductive material.

In the conductive particles,

The first metal powder may be made of a material exhibiting magnetism, and the second metal powder may be made of a non-magnetic conductive material.

In the conductive particles,

The second metal powder may be made of a material having better conductivity than the first metal powder.

In the conductive particles,

The second metal powder may be made of a material exhibiting magnetism, and the first metal powder may be made of a non-magnetic conductive material.

In the conductive particles,

The first metal powder may be made of a material having higher conductivity than the second metal powder.

In the conductive particles,

The core particles are provided with pores inside, pores are provided in the outer skin layer, and some of the pores of the core particles and the pores of the outer skin layer may communicate with each other.

In the conductive particles,

The core particle is made of a polyhedron having three or more surfaces, and the outer skin layer may cover at least two surfaces of the core particle.

According to the present invention, conductive particles can be manufactured from metal powder made of different materials through two or more sintering processes, so that the conductive particles suitable for the characteristics required by the test socket can be conveniently and quickly manufactured.

The present invention has the advantage of being able to manufacture conductive particles that satisfy conductivity and durability.

The present invention has an advantage in that the conductive particles do not escape from the conductive part because the silicone rubber penetrates into the pores and is firmly bonded by manufacturing conductive particles having pores penetrated to the inside.

1 is a view showing the appearance of a general anisotropic conductive sheet.
FIG. 2 is a diagram illustrating an electrical test of a device under test using the anisotropic conductive sheet of FIG. 1; FIG.
FIG. 3 is a view showing a state in which conductive particles are separated from a conductive part in the electrical inspection process of FIG. 2;
4 is a view showing a manufacturing process for manufacturing conventional conductive particles.
5 is a view showing a manufacturing process for manufacturing conventional conductive particles.
6 is a perspective view of conductive particles according to an embodiment of the present invention.
Fig. 7 is a VII-VII sectional view of Fig. 6;
8 is a view showing one shape of a substrate used in the manufacturing process of the present invention.
Figure 9 is a block diagram of the manufacturing process of Figure 8
10 is a view showing how an anisotropic conductive sheet is manufactured using the conductive particles manufactured in FIG. 8;
11 and 12 are real pictures of the conductive particles prepared in FIG. 8 .

Embodiments of the present disclosure are illustrated for the purpose of explaining the technical idea of the present disclosure. The scope of rights according to the present disclosure is not limited to the specific description of the embodiments or these embodiments presented below.

All technical terms and scientific terms used in this disclosure have meanings commonly understood by those of ordinary skill in the art to which this disclosure belongs, unless otherwise defined. All terms used in this disclosure are selected for the purpose of more clearly describing the disclosure and are not selected to limit the scope of rights according to the disclosure.

Expressions such as "comprising", "including", "having", etc. used in this disclosure are open-ended terms that imply the possibility of including other embodiments, unless otherwise stated in the phrase or sentence in which the expression is included. (open-ended terms).

Expressions in the singular form described in this disclosure may include plural meanings unless otherwise stated, and this applies equally to expressions in the singular form described in the claims.

Expressions such as "first" and "second" used in the present disclosure are used to distinguish a plurality of elements from each other, and do not limit the order or importance of the elements.

In the present disclosure, when an element is referred to as being “connected” or “connected” to another element, that element is directly connectable or connectable to the other element, or a new It should be understood that it can be connected or connected via other components.

The direction indicator of "upper" used in the present disclosure is based on the direction in which the connector is positioned relative to the test device, and the direction indicator of "downer" means the opposite direction of the upward direction. It should be understood that the direction indicator of “up and down direction” used in the present disclosure includes an upward direction and a downward direction, but does not mean a specific one of the upward and downward directions.

Embodiments are described with reference to examples shown in the accompanying drawings. In the accompanying drawings, like reference numerals are assigned to identical or corresponding components. In addition, in the description of the following embodiments, overlapping descriptions of the same or corresponding components may be omitted. However, omission of a description of a component does not intend that such a component is not included in an embodiment. In addition, embodiments of the disclosed manufacturing method may include some or all of the steps shown in the drawings. The steps shown in the figures may be performed sequentially, at least two or more of the steps shown in the figures may be performed simultaneously, or one of the steps shown in the figures may be performed dependent on the other steps. In addition, some of the steps shown in the drawings may be repeatedly performed, and the steps shown in one embodiment do not mean the final steps.

Embodiments described below and examples shown in the accompanying drawings relate to conductive particles used in an anisotropic conductive sheet, which is a component of a test socket for electrical connection of two electronic devices.

The test socket to which the conductive particles shown in the embodiments are applied may be used to electrically connect the test apparatus and the device under test during the electrical test of the device under test. For example, a test socket using conductive particles may be used for a final electrical test of a device under test in a later process of manufacturing a device under test. However, an example of a test to which the test socket is applied is not limited to the aforementioned test.

A device to be tested in which an electrical test is accommodated using a test socket may be a semiconductor package, but is not limited thereto. A semiconductor package is a semiconductor device in which a semiconductor IC chip, a plurality of lead frames, and a plurality of terminals are packaged in a hexahedral shape using a resin material. The semiconductor IC chip may be a memory IC chip or a non-memory IC chip. As the terminal, a pin, a solder ball or the like can be used. The device under test shown in FIG. 1 has a plurality of hemispherical terminals on its lower side.

A test apparatus that applies an electrical signal to a device under test through a test socket may test electrical characteristics, functional characteristics, operation speed, and the like of the device under test. The test device may have a plurality of terminals capable of outputting an electrical test signal and receiving a response signal in a board where the test is performed.

The anisotropic conductive sheet may be disposed to be in contact with the terminal of the test device by the socket housing. The electrical test is performed while the terminal of the device under test is electrically connected to the terminal of the corresponding test device through the anisotropic conductive sheet. The anisotropic conductive sheet has a structure in which conductive particles are distributed in a soft elastic material such as silicone rubber, so that when it comes into contact with a device under test, soft contact with the device under test is possible, thereby preventing damage to the device under test. there will be

The conductive particles according to the present embodiment are used in an anisotropic conductive sheet for electrical connection between a terminal of a device under test and a pad of a test device, and are contained in a plurality in an elastic insulating material and come into contact with each other by pressing the device under test. It is used to form a conductive path for electrical connection between the terminal and the pad.

A method of manufacturing such conductive particles 21 will be described with reference to FIGS. 8 and 9 .

First, as shown in FIG. 8 (a), a mold substrate 40 in the form of a substrate is prepared (S100). At this time, the mold substrate 40 is made of materials such as silicon, glass, quartz, ceramics, etc. so that it can be used repeatedly. It is preferable to use, but is not limited thereto, and of course, any material having excellent durability can be used so that it can be reused repeatedly.

Subsequently, as shown in FIG. 8(b), a groove 40a for forming conductive particles 21 having a shape corresponding to the desired conductive particles 21 is formed on the upper surface of the mold substrate 40 (S200 ). Specifically, in order to manufacture the disk-shaped conductive particles 21 shown in FIG. 6, a groove 40a for forming the conductive particles 21 having a shape corresponding to the corresponding conductive particles 21 is formed on one surface of the mold substrate 40. (preferably the upper surface).

The size of the grooves 40a for forming the conductive particles 21 is somewhat smaller than that of the conductive particles 21 manufactured in consideration of the extent to which the volume of the first metal powder 21' is reduced in the process of manufacturing the conductive particles 21. It is better to make it large. Since there is a difference in shrinkage rate depending on heating temperature and material, etc., it is desirable to determine the size after identifying an appropriate numerical range through multiple repetition tests.

As a method of forming the grooves 40a for forming the conductive particles 21 on one surface of the mold substrate 40, various methods such as dry etching, laser processing, and chemical etching can be used.

Then, as shown in FIG. 8(c), the inside of the groove 40a for forming the conductive particles 21 is filled with the first metal powder 21'. (S300) At this time, the first metal powder 21' ) is injected into the groove in an appropriate amount according to the groove 40a for forming the conductive particles 21, and filled to have a shape corresponding to the shape of the desired conductive particle 21.

As the first metal powder 21', iron, nickel, cobalt, and those coated with copper or resin may be used. Specifically, highly conductive metals, ferromagnetic metals, ceramics, high-strength metals, and combinations thereof may be used. A mixture of a carbon material and a combination thereof may be used.

In this case, the highly conductive metal may include gold, silver, copper, palladium, rhodium, platinum, or the like, and may have a conductivity of 5 × 10 ⁶ Ω ¹ m ^-1 or more at 0 °C.

Ferromagnetic metals may include cobalt, nickel, iron, ferrite, and the like, and high-strength metals may include tungsten and titanium. In this case, the ferromagnetic metal powder may preferably have a saturation magnetization of 0.1 Wb/m2 or more, more preferably 0.3 Wb/m2 or more, and particularly preferably 0.5 Wb/m2 or more, specifically iron, nickel, or cobalt. or alloys thereof, among which alloys made of nickel or cobalt are preferable.

If this saturation magnetization is 0.1 Wb/m 2 or more, the conductive particles 21 can be easily moved in the molding material layer for forming the anisotropic conductive sheet 10 by a method described later, and thereby in the molding material layer. A chain of the conductive particles 21 can be formed by reliably moving the conductive particles 21 to the portion used as the conductive portion 20 for connection in the case.

In addition, the carbon material may include CNT, carbon fiber, fullerene, graphene, and the like.

Subsequently, as shown in FIG. 5(d), the first metal powder 21' is heated to produce the solidified core particle 21a. (S400) Specifically, the first metal powder 21' By heating at a temperature close to the melting point, the metal powder powder adheres to each other and solidifies. At this time, the heating temperature for sintering may start from 10% based on the melting point of the material of the metal powder depending on the size of the metal powder powder, and the effective heating temperature for sintering is preferably 45 to 97% of the melting point.

In this way, when the metal powder is heated at a high temperature, the surface area in contact with the outside is reduced as atoms or molecules per unit area are aggregated with each other. In this process, it is possible to obtain core particles 21a whose volume is reduced rather than the existing grooves 40a for formation of conductive particles 21 . In consideration of the fact that the particles solidified after heating are somewhat smaller in volume than the grooves 40a for forming the conductive particles 21, the grooves 40a for forming the conductive particles 21 are slightly larger than the desired particles on the substrate. It is good to arrange

Subsequently, in the groove 40a for forming the conductive particles 21 in FIG. 8(e), the second metal powder 21'' made of a material different from the first metal powder around the core particle 21a. ) will be filled in. (S500)

Specifically, the second metal powder (21'') is filled in the space between the core particle (21a) in the groove of the conductive particle (21), the side surface of the groove of the conductive particle (21), and the space above the core particle (21a). do.

The second metal powder 21'' is made of a material somewhat different from the first metal powder 21'. For example, when the first metal powder 21' is made of a material exhibiting magnetism, the second metal powder 21' The metal powder 21'' may be made of a non-magnetic highly conductive material. In this case, it is not necessary to perform a plating operation with a separate highly conductive metal on the surface of the finally manufactured conductive particles 21 .

In addition, it is possible to make the first metal powder 21' made of a highly conductive material and the second metal powder 21'' made of a material showing magnetism. In this case, since the magnetic material is included outside while manufacturing the particles mainly composed of the highly conductive material, it is possible to conveniently manufacture the particles showing excellent conductivity and exhibiting magnetism.

In addition, both the first metal powder 21' and the second metal powder 21'' are mixed with a magnetic powder exhibiting magnetism and a conductive powder having excellent conductivity, but in the first metal powder 21', the magnetic powder It is possible to make the ratio higher than that of the conductive powder, and to make the ratio of the conductive powder higher than that of the magnetic powder in the second metal powder 21''.

The first metal powder 21' and the second metal powder 21'' are mixed with magnetic powder showing magnetism and conductive powder having excellent conductivity, but the ratio of the conductive powder in the first metal powder 21' is It is possible to set the ratio higher than that of the magnetic powder, and in the second metal powder 21'', the ratio of the magnetic powder is higher than the ratio of the conductive powder.

In this way, the second metal powder 21'' is made of a single material or a mixed material having characteristics different from that of the first metal powder 21', so that the conductive particles 21 fit in appropriate positions according to various characteristics of the test socket. ) can be custom-made.

In FIG. 8(f), the second metal powder 21'' is heated at a temperature lower than the melting point of the second metal powder 21'' to reduce the volume of the groove 40a for forming the conductive particles 21. The solidified conductive particles 21 are prepared. (S600)

In the conductive particles 21 manufactured by sintering in this way, the outer layer 21b made of the second metal powder 21'' covers the surface of the core particle 21a made of the first metal powder 21'. will have In addition, since the manufactured conductive particles 21 are reduced in volume due to sintering, they are not attached to the surface of the mold substrate 40 and are spaced apart at predetermined intervals, so that they can be easily separated.

At this time, the heating temperature for heating the second metal powder 21'' is preferably lower than the melting point of the second metal powder 21'' and additionally lower than the melting point of the first metal powder 21'. . That is, when heated to a temperature higher than the melting point of the first metal powder 21', the core particles 21a inside the second metal powder 21'' may be in a molten state, but the first metal powder If it is lower than the heating temperature of (21'), the outer skin layer 21b can be formed on the surface of the core particle 21a in a new sintered body while the core particle 21a remains solid.

In addition, it is preferable that the heating temperature at the time of manufacturing the core particle 21a is higher than the heating temperature at the time of forming the outer skin layer 21b, and the melting point of the first metal powder 21' is the second metal powder 21 It is better that it is equal to or higher than the melting point of ''). However, it is not limited thereto, and a material and temperature may be appropriately selected according to the characteristics of the manufactured conductive particles 21 as needed.

Subsequently, as shown in FIG. 8(g), the conductive particles 21 that have been manufactured are separated from the grooves 40a for forming the conductive particles 21. (S700) At this time, the conductive particles 21 are conductive particles. (21) Since it is arranged slightly smaller than the forming groove 40a, the conductive particles 21 can be easily separated from the forming groove 40a.

A method of manufacturing the anisotropic conductive sheet 10 using the conductive particles 21 prepared in FIG. 8 is shown in FIG. 10 .

The conductive particles 21 are introduced into the elastic insulating material 50' in a molten state and mixed homogeneously to produce the molding material 50 in which the conductive particles 21 are evenly dispersed. The manufactured molding material 50 is put into a mold, as shown in FIG. 10 (a).

At this time, the elastic insulating material is preferably a heat-resistant high molecular material having a cross-linked structure. A variety of materials can be used as a curable high molecular substance forming material that can be used to obtain such a crosslinked high molecular substance, but liquid silicone rubber is preferred.

The liquid silicone rubber may be of an addition type or a condensation type, but an addition type liquid silicone rubber is preferable. This addition-type liquid silicone rubber is cured by a reaction between a vinyl group and a Si-H bond, and is a one-liquid (one-component type) composed of polysiloxane containing both a vinyl group and a Si-H bond, and one containing a vinyl group. There is a two-liquid (two-component type) composed of a polysiloxane and a polysiloxane containing a Si-H bond, but in the present invention, it is preferable to use a two-liquid addition type liquid silicone rubber.

On the other hand, the mold 60 into which the molding material is injected is composed of an upper mold 61 and a lower mold 65. In the upper mold 61, a ferromagnetic layer 63 is formed on the lower surface of the ferromagnetic substrate 62 at a position corresponding to the conductive portion 20 of the anisotropic conductive sheet 10 to be molded, and other than the ferromagnetic layer 63 A non-magnetic layer 64 is formed at the portion of , and a molding surface is formed by these ferromagnetic layer 63 and non-magnetic layer 64 .

In the lower mold 65, a ferromagnetic layer 67 is formed on the upper surface of the ferromagnetic substrate 66 according to the same pattern as the arrangement pattern of the conductive parts 20 of the anisotropic conductive sheet 10 to be molded, and this ferromagnetic layer ( 67), non-magnetic layers 68 are formed in portions other than those, and a molding surface is formed by these ferromagnetic layers 67 and non-magnetic layers 68.

The mold has an intensity distribution by operating an electromagnet (not shown) disposed on the upper surface of the ferromagnetic substrate 62 in the upper mold 61 and the lower surface of the ferromagnetic substrate 66 in the lower mold 65. A parallel magnetic field, that is, a parallel magnetic field having a high intensity is applied in the thickness direction between the ferromagnetic layer 63 of the upper mold 61 and the ferromagnetic layer 67 of the lower mold 65 corresponding thereto. As a result, as shown in FIG. 10(b), the conductive particles 21 dispersed in the molding material 50 are transferred to each ferromagnetic layer 63 of the upper mold 61 and the lower mold corresponding thereto. (65) are oriented so as to line up in the thickness direction of the molding material 50 while gathering in the portion to be the conductive path located between the ferromagnetic layers 67.

And, in this state, by curing the molding material 50, as shown in FIG. 10(c), the conductive particles 21 in the elastic polymer material are tightly packed in a state in which they are aligned in the thickness direction and oriented. An anisotropic conductive sheet having conductive parts 20 formed around the conductive parts 20 and insulating parts 30 made of an insulating elastic polymer material having no or almost no conductive particles 21 present therein. (10) is produced.

In the embodiment of the present invention, since the conductive particles 21 are manufactured by the sintering process, pores are formed inside the core particles 21a and the pores are formed in the outer skin layer 21b as well, so that when the liquid material is put into the liquid material, the pores are formed. It penetrates into the pores of the conductive particles 21, and when cured in the mold in this state, silicone rubber, which is an elastic insulating material, penetrates into the inside of the conductive particles 21, and the conductive particles 21 are separated from the conductive part 20. It doesn't work.

In addition, since pores are formed up to the inside of the conductive particles, three-dimensional elastic deformation by external force can be achieved, thereby preventing damage to the conductive particles themselves.

In addition, since a plurality of pores are formed outside the conductive particles, the contact area may be increased when contacting adjacent conductive particles due to the irregular surface, and thus electrical connection capability may be increased.

In addition, the conductive particles 21 are composed of a mixture of a magnetic material and a highly conductive metal material, so that when a magnetic field is applied in the mold, the assembly is easy, so that the conductive particles 21 are formed between the conductive parts 20. distribution will not occur. In particular, since materials having different characteristics are integrally combined by heating, they are not separated by external force.

In addition, even after manufacturing the anisotropic conductive sheet 10, if the highly conductive material is formed on the outer layer 21b, there is an advantage in that the conductivity with the adjacent conductive particles 21 is excellent without the need for a separate plating operation. In particular, since there is no need to additionally coat a highly conductive material such as gold, there is an advantage in that the overall manufacturing time can be remarkably shortened.

In addition, when the outer layer 21b is made of a material with high hardness, the conductive particles 21 are not damaged in the process of frequent connection with terminals, and when the core particles 21a are made of a highly conductive material, electrical signals are transmitted without resistance. be able to communicate well.

In particular, since the inner surface of the outer layer made of a material of high hardness is intertwined with the outer layer of the core particle by pores in the sintering process, there is an advantage in that a large binding force between the outer layer and the core particle can be obtained.

11 and 12 show real pictures of conductive particles 21 manufactured according to an embodiment of the present invention. As shown in FIGS. 11 and 12, when the core particle 21a has a polyhedral shape, the outer skin layer 21b surrounds at least two surfaces of the core particle 21a, so that various characteristics can be effectively displayed.

In particular, conductive particles exhibiting magnetism, excellent conductivity, and improved durability can be easily manufactured in various shapes and structures according to the needs of designers.

In particular, the conductive particles using the existing sintering method are separated from the mold substrate after being sintered once and used. In the method of refilling and sintering, a desired material can be filled in a specific area and sintered, so that not only can the purpose-fitting conductive particles be manufactured, but also the characteristics of the conductive particles can be significantly improved.

In addition, in the anisotropic conductive sheet, the conductive part should be divided into upper / middle / lower parts, and particles optimized for its characteristics should be applied. , The middle part can improve the current characteristics of the entire conductive part when the contact resistance between conductive particles is low, and it is possible to easily manufacture conductive particles having various characteristics according to the characteristics of each region by increasing the number of times of sintering.

In addition, the sintering of a specific area is a big factor that can control the characteristics, and it can improve wear resistance and lifespan, and it is free to select the material that goes into the center of the entire particle or a specific area of the outermost layer. Conductive particles that transmit electrical signals by being contacted several times or tens of thousands of times can selectively manufacture materials with excellent wear resistance or electrical properties in specific areas to compensate for the problem of losing their properties due to accumulated fatigue and wear between particles. will be.

In the above-described embodiment, but exemplifying a method of manufacturing conductive particles using two sintering processes, it is possible to manufacture conductive particles using three or more times, if necessary. In addition, it is also possible to perform additional operations such as performing additional processes or performing plating as a post-process as needed in each step.

Although the present invention has been described in detail with preferred embodiments above, the present invention is not necessarily limited to these embodiments and modifications, and can be variously modified without departing from the technical spirit of the present invention.

10 ... anisotropic conductive sheet 20 ... conductive part
21 ... conductive particles 30 ... insulation
21'...first metal powder 21''...second metal powder
21a ... core particle 21b ... outer layer
40 ... mold substrate 40a ... groove for forming conductive particles

Claims (26)

It is used for the anisotropic conductive sheet for electrical connection between the terminal of the device under test and the pad of the test device, and a plurality of sheets are contained in an elastic insulating material and are in contact with each other by the pressure of the device under test to conduct electrical connection between the terminal and the pad. As a method for producing conductive particles used to form a furnace,
(a) preparing a mold substrate;
(b) forming a groove for forming conductive particles having a shape corresponding to the conductive particles and opened to one side on either side of the mold substrate;
(c) filling the first metal powder into the grooves for forming the conductive particles;
(d) heating the first metal powder at a temperature lower than the melting point of the first metal powder to prepare solid core particles whose volume is reduced compared to the grooves for forming conductive particles;
(e) filling a second metal powder made of a different material from the first metal powder around the core particle in the groove for forming the conductive particle;
(f) heating the second metal powder at a temperature lower than that of the second metal powder to produce solidified conductive particles having a volume smaller than that of the grooves for forming conductive particles. According to claim 1,
After step (f), a step of separating the conductive particles from the grooves for forming conductive particles of the mold substrate is further included. According to claim 1,
A method for producing conductive particles, characterized in that the first metal powder is made of a material exhibiting magnetism, and the second metal powder is made of a non-magnetic conductive material. According to claim 3,
The method of producing conductive particles, characterized in that the second metal powder is made of a material having better conductivity than the first metal powder. According to claim 1,
The method of producing conductive particles, characterized in that the second metal powder is made of a material exhibiting magnetism, and the first metal powder is made of a non-magnetic conductive material. According to claim 5,
A method for producing conductive particles, characterized in that the first metal powder is made of a material having higher conductivity than the second metal powder. According to claim 1,
The first metal powder is a mixed powder containing a magnetic powder showing magnetism and a non-magnetic conductive powder, wherein the mixed powder contains the magnetic powder in a higher ratio than the conductive powder. Method for producing conductive particles. According to claim 1,
The first metal powder is a mixed powder containing a magnetic powder showing magnetism and a non-magnetic conductive powder, wherein the mixed powder contains the conductive powder in a higher ratio than the magnetic powder powder. Method for producing conductive particles. According to claim 1,
The method of producing conductive particles, characterized in that the conductive particles prepared in step (f) have a plurality of pores formed therein. According to claim 9,
A method for producing conductive particles, characterized in that a plurality of pores connected to internal pores are formed on the outside of the conductive particles prepared in step (f). According to claim 1,
The heating temperature in step (d) is a method for producing conductive particles, characterized in that higher than the heating temperature in step (f). According to claim 1,
The method of producing conductive particles, characterized in that the melting point of the first metal powder is equal to or higher than the melting point of the second metal powder. According to claim 1,
The heating temperature in steps (d) and (f) is a method for producing conductive particles, characterized in that the temperature is lower than the melting point of the first metal powder and the second metal powder. It is used for the anisotropic conductive sheet for electrical connection between the terminal of the device under test and the pad of the test device, and a plurality of sheets are contained in an elastic insulating material and are in contact with each other by the pressure of the device under test to conduct electrical connection between the terminal and the pad. As a method for producing conductive particles used to form a furnace,
(a) preparing a mold substrate;
(b) forming a groove for forming conductive particles having a shape corresponding to the conductive particles and opened to one side on either side of the mold substrate;
(c) filling the first metal powder into the grooves for forming the conductive particles;
(d) heating the first metal powder at a temperature lower than the melting point of the first metal powder to produce solid first particles whose volume is reduced from that of the grooves for forming conductive particles;
(e) filling a second metal powder made of a different material from the first metal powder around the first particles in the groove for forming the conductive particles;
(f) heating the second metal powder at a temperature lower than that of the second metal powder to produce second particles in which the volume is reduced and solidified than the grooves for forming conductive particles and the first particles are integrally bonded therein; Method for producing conductive particles, characterized in that it comprises. According to claim 14,
After step (f),
A method for producing conductive particles, characterized in that the conductive particles are produced by repeating steps (e) and (f) at least once using a different type of metal powder made of a material different from the first metal powder. As the conductive particles produced by the manufacturing method of claim 1 or claim 14,
A core particle made of the first metal powder as a material;
Conductive particles comprising a second metal powder as a material and an outer layer covering at least a portion of the core particles. According to claim 16,
The conductive particles are conductive particles, characterized in that a plurality of pores are formed inside the inner core particles. The conductive particle according to claim 17, wherein the plurality of pores are connected to the surface of the conductive particle. According to claim 16,
The core particle is made of a polyhedron,
The outer skin layer is conductive particle, characterized in that surrounding at least two or more surfaces of the core particle. It is used for the anisotropic conductive sheet for electrical connection between the terminal of the device under test and the pad of the test device, and a plurality of sheets are contained in an elastic insulating material and are in contact with each other by the pressure of the device under test to conduct electrical connection between the terminal and the pad. As the conductive particles used to form the furnace,
Core particles made of a conductive material and solidified by sintering the first metal powder; and
At least a portion of the core particle is surrounded,
It consists of a second metal powder made of a material different from the first metal powder,
Conductive particles characterized in that they are solidified by sintering the second metal powder and include an outer layer made of a conductive material. According to claim 20,
Conductive particles, characterized in that the first metal powder is made of a material exhibiting magnetism, the second metal powder is made of a non-magnetic conductive material. According to claim 21,
The second metal powder is conductive particles, characterized in that made of a material superior in conductivity performance than the first metal powder. According to claim 20,
Conductive particles, characterized in that the second metal powder is made of a material exhibiting magnetism, the first metal powder is made of a non-magnetic conductive material. According to claim 23,
Conductive particles characterized in that the first metal powder is made of a material having higher conductivity than the second metal powder. According to claim 20,
Conductive particles, characterized in that pores are provided inside the core particles, pores are provided in the outer layer, and some of the pores of the core particles and the pores of the outer layer are in communication with each other. According to claim 20,
Conductive particles, characterized in that the core particle is made of a polyhedron having three or more surfaces, and the outer skin layer surrounds at least two surfaces of the core particle.

Images