KR101912565B1 - Device for manufacturing of bonding wire - Google Patents

Abstract

The present invention relates to an apparatus for manufacturing bonding wires having an intermediate layer between metal materials by injecting molten gold to the skin of a silver or copper core. The manufacturing apparatus includes: a casting housing which has a die coupling unit formed on the lower part and heats a heating furnace installed therein; a crucible which has an outlet formed on the lower part and is inserted in the heating furnace to melt the metal materials on the skin layer input to the inside by using the induction heating coils; a core guide which is installed toward the outlet while being spaced apart from the inner and lower surface of the crucible and guides the conveyance of the core metal wires inserted into the hollow parts to the lower outlet; a gate pole which is coupled to the outer peripheral surface of the core guide to be lifted up and down, blocks the molten substances in the crucible from flowing to the outlet in normal situations by making the lower end come in contact with the upper surface of the outlet of the crucible, and forms a flow path from the inside of the crucible to the outlet by being lifted up in a casting operation; and a die cooler which protrudes and is coupled to the upper part of the inner surface of the crucible through the die coupler of the casting housing, bonds the skin layer metal substances melt in the crucible to the skin of the core metal wires being conveyed to the lower outlet through the core guide by lifting the gate pole, and casts and cools a wire precursor having an inter-metal intermediate layer mixing the core metal and skin layer metal substances onto the surface of the core metal wires.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding wire manufacturing apparatus, and more particularly, to a bonding wire manufacturing apparatus for manufacturing a bonding wire, which comprises gold (Ag) A core metal made of any one selected from the group consisting of gold (Au), palladium (Pd), platinum (Pt), silver alloy (alloy of silver and platinum, palladium, rhodium, iridium) And a mother wire having an intermetallic phase intermetallic phase between the metal wire and the epidermal metal is formed and stretched at least once by a die stretcher to manufacture a bonding wire.

The bonding wire is used in the manufacturing process of the semiconductor device to electrically connect the integrated circuit and the printed circuit board in manufacturing the semiconductor device. Bonding wires are also used in power electronics applications to electrically connect transistors, diodes, etc. to the pads or pins of the housing. Initially, the bonding wires were made of gold, but nowadays inexpensive metal materials such as silver, copper, and aluminum are used.

In the present invention, the term "bonding wire" encompasses all cross-sectional shapes and all conventional wire diameters, but a circular cross-section and a narrow diameter bonding wire is preferred.

Although silver wires provide very good electrical conductivity and thermal conductivity, silver wire bonding has its own problems. Some recent research and development are aimed at a bonding wire having a core metal based on silver as a main component because silver is cheaper than gold. As such prior art, there is disclosed in Japanese Patent Application Laid-Open No. 10-2014-0031111 Quot; alloy wire for bonding application ", which is disclosed in Patent Document 1). Nevertheless, there remains a need to further improve the bonding wire technology with respect to the bonding wire itself and the bonding process.

Much research has been conducted to replace the gold bonding wire, and examples thereof include a bonding wire mainly composed of copper. However, since the single copper bonding wire is easily oxidized in the air, the bonding property with the bonding pad or the lead may be problematic. To improve this, a double-layered copper bonding wire for coating the surface of a single-layered copper bonding wire with another metal has been proposed in Japanese Patent Application Laid-Open No. 2006-190763 (published on July 20, 2006).

The "bonding wire for a semiconductor device" described in Patent Document 2 is a bonding wire having a core material containing copper as a main component and a skin layer of a conductive metal having a composition different from that of the core material. Characterized in that a main component of the skin layer is at least two selected from gold, palladium, platinum, rhodium, silver or nickel, and a site having one or both concentration gradient of the main component metal or copper in the wire diameter direction exists in the skin layer .

In order to manufacture the double-layered copper bonding wire described in Patent Document 2, when a different kind of metal is formed on the copper core, and then the drawing process is repeated several times while the heat treatment is performed, the copper core may be exposed due to the peeling of different metals. If the copper core material is exposed in this manner, problems such as a copper bonding wire of a single layer may occur, which may cause defects when applied to a semiconductor device.

In addition, there is also a demand for improving the bonding properties of the double-layered copper bonding wire bonded to the bonding pad or the lead, and since the purity of copper selected as the core material is very high, the wires are bent after bonding, So that it is necessary to improve the straightness.

The bonding wire is formed of a core material and a skin layer, which are the main components of the wire. Examples of a method of forming a skin layer on the core material include a vapor deposition method and a melting method.

As the deposition method, a physical vapor deposition method such as a sputtering method, an ion plating method, a vacuum deposition method, or a chemical vapor deposition method such as a plasma enhanced chemical vapor deposition method can be used. When the evaporation method is used, since the cleaning is not necessary after the film formation, the problem of contamination due to cleaning does not occur.

The melting method is a method of injecting molten metal into a molten metal by melting any one of a skin layer or a core material and injecting molten metal of the skin layer around the core material previously prepared to form a skin layer, Alternatively, it may be manufactured by injecting a core material into the center of a hollow circumference of a previously prepared skin layer.

However, the deposition method is to deposit the surface layer metal on the surface of the mother wire (for example, the precursor before the production of the bonding wire), so that the mother wire is formed into a bonding wire having a diameter of 50 mu m to 350 mu m There is a problem that the metal of the skin layer is boiled or peeled off.

In addition, the melting method according to the prior art is to inject molten metal around the core material which is prepared in advance, which leads to many difficulties in manufacturing. For example, when the surface layer metal such as molten gold is injected onto the surface of a core made of silver or the like, the surface layer metal melted by the large temperature difference between the melted skin layer metal and the core material penetrates sufficiently into the core of the core ), The bond strength between the core material and the skin layer metal decreases. In such a state, when the mother wire is formed into a bonding wire having a diameter of 50 mu m to 350 mu m by the die stretching machine, there is a problem that the surface layer metal is boiled or peeled.

10-2014-0031111 A1 (Released on March 12, 2014) JPA 2006-190763 (Released on July 20, 2006)

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to provide a wire drawing method capable of reducing damage of a chip while preventing exposure of core metal, The present invention provides an apparatus for manufacturing a bonding wire excellent in bonding property at the second side where stitch bonding is performed.

It is another object of the present invention to provide a method for manufacturing a core metal wire, which comprises melting a surface layer metal to be melt-bonded to a skin of a core metal in a crucible, heating core metal constituting a main component of the wire and fusing and bonding the melted skin metal to the surface of the core, Continuously casting a precursor having intermetallic phases intermediate layers formed by mixing the surface skin layer metal material and the core metal material on the surface of a substrate, and stretching the precursor produced by the continuous casting to form a bonding wire, .

According to an aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: melting a surface layer metal of a bonding wire into a crucible having a die cooler at a lower portion thereof; The main core metal of the wire is inserted into the core guide positioned above the die cooler of the crucible and the core guide is heated below the melting point of the core metal to soften the core metal; The core metal is transferred to the die cooler so that the melted skin layer metal is fusion bonded to the skin of the core metal to form intermetallic phases intermetallic phases in which the skin layer metal material and the core metal material are mixed, Casting a formed bonding wire precursor; And a step of preparing the bonding wire precursor using the die stretcher as a bonding wire having a predetermined diameter.

Wherein the surface layer metal is any one selected from the group consisting of gold, palladium, platinum, silver alloy (an alloy of silver and platinum, palladium, rhodium and iridium) or an alloy thereof, Or a metal wire made of one of these alloys.

According to another aspect of the present invention, there is provided a bonding wire manufacturing apparatus comprising: a casting housing for heating a heating furnace formed therein by an induction heating coil provided at a lower portion thereof with a die coupling, and; A crucible having a discharge port formed at a lower portion thereof to be inserted into a heating furnace of the casting housing and dissolving the surface layer metal charged therein by heating the induction heating coil; A core guide spaced apart from an inner lower surface of the crucible to guide the core metal wire inserted toward the discharge port and inserted in the hollow into the lower discharge port of the crucible; And a lower end portion of the crucible is brought into contact with the upper surface of the outlet of the crucible so that the melt in the crucible is prevented from flowing toward the discharge port and is raised during casting to flow from the inside of the crucible to the discharge port, A gate pole forming a gate electrode; The molten skin layer metal is bonded to the skin of the core metal wire which is projected to the upper part of the inner surface of the crucible through the die fitting of the casting housing and is conveyed to the lower outlet through the core guide by the rise of the gate pole, A die cooler for casting a wire precursor having an intermediate layer of intermetallic phases formed by mixing the surface layer metal material and the core metal material on a surface of the core metal wire and cooling the wire precursor; And the wire precursor in the die cooler is constituted by a drawing machine that draws (draws) the wire precursor to a size of 50 mu m to 350 mu m.

The core guide is made of the same material as the crucible, and an induction heating coil is installed in the core guide to heat the core metal wire to a melting point or less of the core metal wire.

Wherein the surface layer metal is any one selected from the group consisting of gold, palladium, platinum, silver alloy (an alloy of silver and platinum, palladium, rhodium and iridium) or an alloy thereof, Or a metal wire made of one of these alloys.

In the present invention, the term "intermediate layer" is the area of the wire between the core metal and the skin layer metal. In this region, the materials in the core metal as well as the materials in the skin layer metal are present in combination in the form of, for example, at least one intermetallic phase.

In the context of the present invention, the term "intermetallic phase" refers to a phase of two or more metals in which the different elements are different sites within the structure, and the sites are in different localized environments and often with well-defined fixed stoichiometries Lt; RTI ID = 0.0 > regularly < / RTI > This is the difference for alloys in which the different elements are randomly distributed.

In the bonding wire manufacturing apparatus according to the embodiment of the present invention, a wire precursor having intermetallic phases intermediate layers formed by mixing the surface layer metal material and the core metal material is formed on the surface of the core metal, and the wire precursor is stretched by a die stretching process, It is possible to improve the bonding property of the second side in which stitch bonding is performed because it is not peeled or broken. And the material cost of the bonding wire can be reduced.

1 is a cross-sectional view of a bonding wire manufactured in accordance with a preferred embodiment of the present invention.
2 is a longitudinal sectional view of a bonding wire manufactured according to a preferred embodiment of the present invention;
FIG. 3 is a cross-sectional view of a bonding wire manufacturing apparatus according to a preferred embodiment of the present invention, wherein FIG. 3a is a state before casting a bonding wire precursor, and FIG. 3b is a casting state of a bonding wire precursor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. It is also to be understood that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It should be noted that the embodiments of the present invention described below are intended to sufficiently convey the spirit of the present invention to those skilled in the art.

1 and 2 show a cross-section and a longitudinal section of a wire 1 produced by a bonding wire manufacturing apparatus according to a preferred embodiment of the present invention. In the cross section, the core metal 2 is at the center. The core metal 2 is surrounded by a skin layer metal 3 and an intermediate layer 4 is formed between the core metal 2 and the skin layer metal 3.

At this time, the intermediate layer 4 is formed of gold (Au) having a purity of 99.99% on the skin of any one wire selected from the group consisting of silver (Ag), copper (Cu) and aluminum (Al) (3) is bonded by fusing a skin material of any one selected from the group consisting of palladium (Pd), platinum (Pt) or silver alloy (alloy of silver and platinum, palladium, rhodium, iridium) Is injected into the inside of the core metal 2. In this case, In other words, the phosphorus layer metal 3 is melted and bonded to the surface of the core metal 2 to be welded.

Since the intermediate layer 4 in which the skin layer metal 3 is melted and bonded to the skin of the core metal 2 as described above is an alloy of the core metal 2 and the skin layer metal 3, the straightness of the wire 1 is improved. That is, since the elasticity of the bonding wire 1 is increased by the formation of the intermediate layer 4, the phenomenon that the adjacent wires come into contact with each other during the stitch bonding is greatly reduced.

In this case, the total diameter r1 of the bonding wire 1 including the skin layer is 30 to 350 m and the diameter r2 of the core metal 2 is 70 to 80% of the total diameter r1 .

The bonding wire 1 shown in Figs. 1 and 2 is manufactured by the manufacturing apparatus of Fig.

A manufacturing process of the bonding wire 1 according to the present invention will be described with reference to FIGS. 3A and 3B.

3A and 3B, the bonding wire manufacturing apparatus 10 includes a heating furnace (not shown) provided inside by a induction heating coil 23 provided at a lower portion thereof with a die coupling 15, And a casting housing (20) for heating the casting mold (21).

The furnace 22 of the casting housing 20 is provided with a discharge port 25 at a lower portion thereof. The crucible 22 is made of a metal such as gold (Au), palladium (Pd), or the like, which has been put into the crucible 22 by heat conduction of the heating furnace 21 heated by the heating of the induction heating coil 23. [ , Platinum (Pt), silver alloy (an alloy of silver and platinum, palladium, rhodium, iridium), or any of these alloys. At this time, the internal temperature of the crucible 22 is maintained at about 1,100 to 2,000 DEG C in accordance with the melting point of the surface layer metal 3 which is put into the crucible 22. [

A core guide (5) having a hollow (13) is provided in the crucible (22). A gate pawl 51 is lifted and locked around the outer circumferential surface of the core guide 5. The lower end of the gate pawl 51 is normally brought into contact with the upper surface of the discharge port 25 of the crucible 22 to prevent the melt in the crucible 22 from flowing to the discharge port 25, (24) from the inside of the discharge port (22) toward the discharge port (25).

At this time, it is preferable that the core guide 5 and the gate pawl 51 are made of the same material as the crucible 22, for example, carbon. An induction heating coil 12 for heating the core metal 2 inserted into the hollow 13 may be installed in the core guide 5.

The core guide 5 is installed to be spaced apart from a discharge port 25 formed at a lower portion of the crucible 22. That is, the core guide 5 is spaced apart from the inner bottom surface of the crucible toward the outlet 25, and the gate pawl 51 is moved upward and downward from the bottom of the crucible 22 toward the core guide 5 The flow passage 24 is opened.

The core guide 5 having the above configuration guides the wire of the core metal 2 which is the main component of the bonding wire inserted into the hollow 13 to be conveyed toward the lower outlet 25 of the crucible 22.

The induction heating coil 12 provided inside the core guide 5 is heated to a suitable temperature according to the material of the core metal 2.

For example, when the core metal 2 is silver (Ag), it is heated to a temperature of 750 to 900 ° C .; when the core metal 2 is aluminum, the core metal 2 is heated to 450 to 600 ° C, , It is heated to 900 to 800 DEG C and put into the hollow 13 to soften the texture of the core metal 2 which is transported downward.

The reason why the induction heating coil 12 is selectively controlled according to the material of the core metal 2 is that the molten gold (Au), palladium (Pd), platinum (Pt), silver alloy (3) having at least one of the metals (1) and (2) and the alloy of the platinum, palladium, rhodium and iridium has a melting point of 1,063 to 1,773 ° C., The temperature of the guide 5 is heated to 800 to 1000 占 폚 to soften the metal structure of the copper (Cu) core metal wire 2 transferred therein to melt the gold (Au) of the skin metal layer 3 It is to be good.

A die of a die cooler 40 is inserted and coupled to a die coupling 15 formed at a lower portion of the casting housing 20 and an extrusion port 42 of the die is connected to a discharge port 25 As shown in Fig.

A lid 30 is hinged to the upper portion of the casting housing 20. The inner crucible 22 of the casting housing 20 can be brought into a vacuum state after the lid 30 is closed and can be oxidized by the oxidation of the wire of the core metal 2 fed into the hollow 23 of the core guide 5, An atmosphere gas, for example, nitrogen, may be charged.

A discharge roller 50 is provided on the discharge path of the die cooler 40 and the discharge roller 50 is connected to the pneumatic cylinder 60 to discharge the start rod SR or the wire precursor P Thereby adjusting the interval.

Although not shown in the drawing, at least one die stretching device is provided at the rear end of the discharge roller 50. The die stretchers stretch the wire precursor (P) produced in the bonding wire manufacturing apparatus (10) to produce a bonding wire having a thickness of 30 to 350 mu m.

The crucible 22 of the bonding wire manufacturing apparatus 10 constructed as described above is made of a material selected from the group consisting of gold (Au), palladium (Pd), platinum (Pt), silver (alloy of silver and platinum, palladium, rhodium and iridium) The surface layer metal 3 injected into the crucible 22 is melted by the heating of the induction heating coil 23 when the skin layer metal 3 made of one or more of these alloys is injected.

The core metal 2 made of any one selected from the group consisting of silver (Ag), copper (Cu), and aluminum (Al) or an alloy thereof is melted in the molten state of the core layer 2 inserted into the crucible 22, The melted skin layer metal 3 passes through the gap 24 between the core guide 5 and the crucible 22 to the surface of the core metal 2 And the material of the skin layer metal 3 is injected into the skin layer of the core metal 2 to form the intermediate layer 4 as shown in Fig. The intermediate layer (4) is a region of the wire between the silver core metal and the skin layer metal. In this region, the materials in the core as well as the materials in the skin layer metal are present in combination in the form of, for example, at least one intermetallic phase.

Example

In order to manufacture the wire precursor P for manufacturing the bonding wire 1 shown in Figs. 1 and 2 by using the bonding wire manufacturing apparatus 10 shown in Fig. 3, The gate pawl 51 coupled to slide up and down on the outer circumference of the die cooler 40 must be closed to close the flow passage 24 and the starter rod SR must be inserted into the extrusion port 42 of the die cooler 40 do.

Thereafter, the lid 30 of the casting housing 20 is opened and gold (Au), palladium (Pd), platinum (Pt), silver alloy (alloy of silver and platinum, palladium, rhodium and iridium) The skin layer metal 3 made of any one selected or alloy thereof is put in, and the lid 30 is closed.

Then, the core metal 2 is inserted into the hollow of the core guide 5 provided at the lower portion thereof through the packing hole 8 formed in the upper portion of the lid 30. At this time, the surface of the wire of the core metal 2 may be coated with borax.

After closing the lid 30, the inside of the casting housing 20 is put in a vacuum state, and an atmosphere gas such as nitrogen is filled in order to prevent the wire of the core metal 2 from being oxidized.

Thereafter, the induction heating coil 23 provided in the casting housing 20 is driven to heat the crucible 22 to a temperature of 1100 to 2000 ° C to melt the surface layer metal contained therein. Then, the induction heating coil 12 provided inside the core guide 5 is heated to a preset temperature.

For example, assuming that the surface layer metal is gold (Au) and the core metal 2 wire is silver (Ag), the core guide 5 is heated to a temperature of 750 to 900 占 폚. The structure of the wire of the core metal (2) fed into the hollow of the core guide (5) by the above heating is softened softly.

When the structure of the core metal 2 is softened in the state where the skin layer metal put in the crucible 22 is melted, the gate pole 51 is raised to open a part of the inner bottom surface of the crucible 22, 24 are formed. When the core metal 2 is inserted into the hollow 13 of the core guide 5 and is transported to the lower portion of the core guide 5 in this state, the molten metal is melted through the flow passage 24 between the core guide 5 and the crucible 22 (3) is melt-bonded to the surface of the core metal (2). At this time, the fusion bonding is strongly melt-bonded by the borax applied to the surface of the core metal (2) wire.

When the wire of the core metal 2 is fed through the hollow 23 of the core guide 5 under the condition that the core guide 5 is heated, the core metal 5 is passed through the core guide 5 by the heating of the induction heating coil 12 When the structure of the core metal 2 is loosened so that the core metal 2 passes through the gap 24 between the core guide 5 and the crucible 22, The surface layer metal 3 is easily melted and adhered to the surface of the core metal 2 and injected into the skin of the core metal 2 wire to form the intermediate layer 4. [

The core metal 2 on which the additional layer 4 is formed sticks to the end of the starter rod SR.

In this state, when the discharge roller 50 is rotated to withdraw the starter rod SR, the skin layer metal 3, which is melt-bonded to the skin of the wire of the core metal 2, The wire precursor P is discharged as shown in FIG. 3B. At this time, the conveying speed of the wire of the core metal 2 conveyed in the core of the core guide 5 is the same as the conveying speed of the precursor P discharged by the discharging roller 50. 3A, when the starter rod SR is drawn out and drawn out by the discharge roller 50 as shown in FIG. 3B, the precursor P is continuously cast.

At this time, the wire precursor P has an intermediate layer 4 as shown in FIG. The intermediate layer (4) is a region of the wire between the silver core metal and the skin layer metal. In this region, the materials in the core as well as the materials in the skin layer metal are present in combination in the form of, for example, at least one intermetallic phase.

The die cooler 40 cools the cast precursor (P). The precursor P cast and cooled by the die cooler 40 is supplied to a die stretcher (not shown) through a discharge roller 50. The die stretcher is at least one or more and is finally made of a bonding wire having a diameter of 30 to 350 mu m.

1: bonding wire, 2: core metal,
3: skin layer metal, 4: middle layer,
5: core guide, 10: bonding wire manufacturing equipment,
12: induction heating coil, 13: hollow,
15: die coupling, 20: casting housing,
21: heating furnace, 22: crucible,
23: induction heating coil, 24: flow passage
25: outlet, 30: cover,
40: die cooler, 42: die extrusion port,
50: discharge roller, 51: gate pole
60: Pneumatic cylinder,

Claims (3)

In a bonding wire manufacturing apparatus,
A casting housing for heating a heating furnace formed therein by a induction heating coil provided at a lower portion thereof with a die coupling hole;
A crucible having a discharge port formed at a lower portion thereof and inserted into a heating furnace of the casting housing and dissolving the surface layer metal charged therein by heating the induction heating coil;
A core guide spaced apart from an inner lower surface of the crucible to guide the core metal wire inserted toward the discharge port and inserted in the hollow into the lower discharge port of the crucible;
And a lower end portion of the crucible is brought into contact with the upper surface of the outlet of the crucible so that the melt in the crucible is prevented from flowing toward the discharge port and is raised during casting to flow from the inside of the crucible to the discharge port, A gate pawl for forming a gate electrode;
The molten skin layer metal is bonded to the skin of the core metal wire which is projected to the upper part of the inner surface of the crucible through the die fitting of the casting housing and is conveyed to the lower outlet through the core guide by the rise of the gate pole, A die cooler for casting a wire precursor on the surface of the core metal wire, the wire precursor having an intermediate layer between the metal matrix and the surface layer metal material mixed with the core metal material;
And a die stretcher for stretching the wire precursor with a wire having a diameter of 50 mu m to 350 mu m in the die cooler. 2. The bonding wire manufacturing apparatus according to claim 1, wherein the core guide is made of the same material as the crucible, and an induction heating coil is installed therein to heat the core metal below the melting point of the core metal. The bonding wire according to claim 1 or 2, wherein the surface layer metal is any one selected from gold, palladium, platinum, and silver alloy or an alloy thereof, and the metal core is one selected from silver, copper, Manufacturing apparatus.

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