KR102125160B1 - Coated wire - Google Patents

Abstract

A wire comprising a wire core having a surface, the wire core having a coating layer superimposed on its surface, the wire core itself:
(a) silver in an amount of 0.1 to 0.3% by weight,
(b) copper in an amount in the range of 99.64 to 99.9% by weight,
(c) phosphorus in an amount ranging from 0 to 100 ppm by weight, and
(d) additional components in amounts ranging from 0 to 500 ppm by weight (different components from silver, copper and phosphorus),
It includes,
The individual amount of any additional component is less than 30 ppm by weight,
All amounts in weight percent and ppm by weight are based on the total weight of the core, and
The coating layer is a double-layer comprising an inner layer of palladium and an adjacent outer layer of gold,
The weight of the inner palladium layer is within the range of 1.5 to 2.5% by weight, compared to the weight of the wire core, and
A wire is provided, wherein the weight of the outer gold layer is within the range of 0.09 to 0.18% by weight, compared to the weight of the wire core.

Description

Coated wire

The present invention relates to a coated wire comprising a copper-based core and a coating layer superimposed on the surface of the core. The invention also relates to a process for making such coated wire.

The use of bonding wires in electronic and microelectronic applications is a well-known prior art. Bonding wires were initially made of gold, but nowadays, less expensive materials such as copper, copper alloys, silver and silver alloys are used. Such wires may be provided with a metal coating.

For wire geometries, the most common are bonding wires of circular cross section and bonding ribbons having a substantially rectangular cross section. Both types of wire geometries have their advantages making them useful for a particular application.

The object of the present invention is a coated copper alloy wire suitable for use in wire bonding applications, wherein the wire is, inter alia, of free air ball (FAB), corrosion resistance, OCB (off center ball), second bond window. To provide a coated copper alloy wire that is improved in morphology but also exhibits a generally well balanced property spectrum related to the wire and bonding applications of the wire, including, for example, distribution of coating materials in FAB, etc. will be.

The contribution to the solution of the above object is provided by the subject matter of the category forming claims. The dependent sub-claims of the category-forming claims represent preferred embodiments of the invention, the subject of which also contributes to solving the object mentioned above.

In a first aspect, the present invention is a wire comprising a wire core having a surface (hereinafter also referred to as "core" for short), the wire core having a coating layer superimposed on its surface, and the wire The core itself is:

(a) 0.1 to 0.3% by weight, preferably 0.2% by weight, of positive silver,

(b) 99.64 to 99.9% by weight, preferably 99.7 to 99.9% by weight, or even more preferably 99.75 to 99.85% by weight, copper in an amount within the range,

(c) phosphorus in an amount of 0 to 100 ppm by weight, preferably 50 to 100 ppm by weight, more preferably 70 to 80 ppm by weight, in particular in the range of 75 ppm by weight, and

(d) 0 to 500 ppm by weight, preferably 0 to 100 ppm by weight, of additional components in the range (components different from silver, copper and phosphorus),

It includes,

The individual amount of any additional component is less than 30 ppm by weight,

All amounts in weight percent and ppm by weight are based on the total weight of the core, and

The coating layer is a double-layer comprising an inner layer of palladium (lower layer) and an adjacent outer layer of gold (upper layer),

The weight of the inner palladium layer is within the range of 1.5 to 2.5% by weight, compared to the weight of the wire core, and

The weight of the outer gold layer relates to the wire, which is within the range of 0.09 to 0.18% by weight, compared to the weight of the wire core.

The table that follows lists some preferred embodiments of the composition of the wire core:

The wire of the present invention is preferably a bonding wire for bonding in microelectronics. It is preferably a single piece object. Numerous shapes are known and are useful for the wires of the present invention. Preferred shapes are circular, elliptical and rectangular in cross section. For the purposes of the invention, the term "bonding wire" includes all shapes of cross-sections and all available wire diameters, although bonding wires with circular cross-sections and thin diameters are preferred. The average cross-sectional area is, for example, in the range of 50 to 5024 μm ² or preferably 113 to 2375 μm ² ; Thus, in the case of a preferred circular cross section, the average diameter is, for example, within the range of 8 to 80 μm or preferably 12 to 55 μm.

The average diameter of a wire or wire core, or simply stated, the diameter can be achieved by a “sizing method”. In this way, the physical weight of the wire for a defined length is determined. Based on this weight, the diameter of the wire or wire core is calculated using the density of the wire material. The diameter is calculated as the arithmetic mean of five measurements for five sections of a particular wire.

As described above, the wire core includes (a) silver, (b) copper, and (c) phosphorus in the proportions described above. However, the silver alloyed copper core of the coated wire of the present invention may comprise (d) 0 to 500 ppm by weight, preferably 0 to 100 ppm by weight of additional components. In the presented context, additional components, often also referred to as "inevitable impurities", are chemical elements and/or compounds, derived from the wires in the raw materials used or from impurities present in the raw materials used, or chemical compounds, ie The presence of additional components of type (d), for example, is derived from impurities inherent in silver and/or copper. Examples of such additional components are Au, Ni, Pd, Pt, Fe, Si, Mn, Cr, Ce, Mg, La, Al, B, Zr, Ti, S, etc. The low total amount of 0 to 500 ppm by weight or even 0 to 100 ppm by weight of the additional components (d) ensures good reproducibility of the wire properties. The additional components (d) present in the core are generally not added separately. Each individual additional component is included in an amount of less than 30 ppm by weight, based on the total weight of the wire core.

The core of the wire is a homogeneous region of bulk material. Since any bulk material can always have a surface area that can exhibit to some extent different properties, the properties of the core of the wire are understood as the properties of the homogeneous area of the bulk material. The surface of the bulk material region may be different in terms of morphology, composition (eg, sulfur, chlorine and/or oxygen content) and other features. The surface is the interface region between the wire core and the coating layer superimposed on the wire core. Typically, the coating layer completely overlaps the surface of the wire core. In the region of the wire between the wire core and the overlying coating layer, a combination of materials of both the core and the coating layer may be present.

The coating layer superimposed on the surface of the wire is a double-layer comprising an inner layer of palladium and an adjacent outer layer of gold. The weight of the inner palladium layer is within the range of 1.5 to 2.5% by weight, compared to the weight of the wire core, and the weight of the outer gold layer is within the range of 0.09 to 0.18% by weight, compared to the weight of the wire core. . Both the inner palladium layer as well as the outer gold layer are thin layers. In this context, the terms “thin”, “thick” or “coating layer thickness” refer to the size of the coating layer in a direction perpendicular to the longitudinal axis of the core. For wires having an average cross-sectional area within the above-described exemplary range of 50 to 5024 μm ² , or for circular wires having an average diameter within the above-described exemplary range of 8 to 80 μm, the inner palladium layer is, for example For example, it may have a thickness in the range of 20 to 350 nm, preferably 30 to 340 nm, and the thickness of the outer gold layer may be, for example, within the range of 1 to 25 nm, preferably 2 to 20 nm. There will be. In an exemplary embodiment of a circular wire having a diameter of 18 μm, the inner palladium layer can have a thickness in the range of, for example, 60 to 90 nm, and the thickness of the outer gold layer, for example, 1 To 10 nm, preferably 2 to 6 nm.

With respect to the composition of the double-layer, the palladium content of the inner layer of the double-layer is, for example, at least 50% by weight, preferably at least 95% by weight, based on the total weight of the inner coating layer. Especially preferably, the inner coating layer is made of pure palladium. Pure palladium generally has less than 1% by weight of additional components (different from palladium), based on the total weight of the inner coating layer. The gold content of the adjacent outer gold layer is, for example, at least 50% by weight, preferably at least 95% by weight, based on the total weight of the outer coating layer. Particularly preferably, the outer coating layer is made of pure gold. Pure gold generally has less than 1% by weight of additional components (components different from gold), based on the total weight of the outer coating layer.

In an embodiment, the core of the wire of the present invention is characterized by at least one of the following intrinsic properties (i) to (iii) (see "Test Method A" as described below):

(i) The average wire particle size (average particle size), measured in the longitudinal direction (the longitudinal direction of the wire core), is 3 to 6 µm,

(ii) The ratio of the average particle size and the diameter of the wire core measured in the longitudinal direction is within the range of 0.05 to 0.25, preferably 0.1 to 0.20,

(iii) The standard deviation ratio (RSD) of the average particle size to the average particle size of the core measured in the longitudinal direction is within a range of 0.1 to 0.4.

The term "unique property" is used herein for a wire core. Intrinsic properties refer to the properties of the wire core itself (regardless of other factors). External properties as opposed to intrinsic properties depend on the relationship of the wire core with other factors, such as the measurement conditions and/or measurement method used.

In another aspect, the invention also relates to a process for the manufacture of the coated wire of the invention in any of the embodiments disclosed below. The process includes at least steps (1) to (5) that follow:

(1) providing a precursor object of the desired composition, i.e.

(a) 0.1 to 0.3% by weight, preferably 0.2% by weight, of positive silver,

(b) 99.64 to 99.9% by weight, preferably 99.7 to 99.9% by weight, or even more preferably 99.75 to 99.85% by weight, copper in an amount within the range,

(c) phosphorus in an amount of 0 to 100 ppm by weight, preferably 50 to 100 ppm by weight, more preferably 70 to 80 ppm by weight, in particular in the range of 75 ppm by weight, and

(d) 0 to 500 ppm by weight, preferably 0 to 100 ppm by weight, in an amount in the range consisting of additional components (components different from silver, copper and phosphorus),

The individual amount of any additional component is less than 30 ppm by weight,

Wherein all amounts in weight percent and ppm by weight are based on the total weight of the precursor object, providing a precursor object;

(2) stretching the precursor object to form an elongated precursor object, until an intermediate cross-sectional area in the range of 5024 to 70650 μm ² and an intermediate diameter in the range of 80 to 300 μm, preferably in the range of 130 to 230 μm, is achieved Prescribing steps,

(3) depositing a double-layer coating of the inner layer of palladium (lower layer) and the adjacent outer layer of gold (upper layer) on the surface of the elongated precursor object obtained after completion of process step (2). ,

(4) further stretching the coated precursor object obtained after completion of process step (3) until the required final cross-sectional area or diameter is achieved, and

(5) The coated precursor obtained after completion of the process step (4), finally at an oven set temperature in the range of 450 to 650° C. for an exposure time within the range of 0.1 to 3 seconds to form a coated wire, finally Strand annealing.

The term "strand annealing" is used herein. As opposed to "batch annealing," this is a continuous process that allows high-speed production of wires with high reproducibility. In the context of the present invention, strand annealing is performed dynamically, while annealing is wound on a reel after the coated precursor to be annealed is pulled or moved through a conventional annealing oven and after leaving the annealing oven. It means Here, the annealing oven is typically in the form of a cylindrical tube of a given length. For example, annealing time/oven temperature parameters can be defined and set, along with their defined temperature profile at a given annealing speed, which can be selected within a range of 10 to 60 meters/minute.

The term "oven set temperature" is used herein. This means the temperature fixed by the temperature controller of the annealing oven.

The annealing oven may be a chamber furnace type oven (in the case of collective annealing) or a tubular annealing oven (in the case of strand annealing).

This disclosure distinguishes precursor objects, elongated precursor objects, coated precursor objects, coated precursors and coated wires. The term “precursor object” is used for those wire pre-steps where the required final cross-sectional area or final diameter of the wire core has not been reached, while the term “precursor” is the wire dictionary at the final cross-sectional area required or final diameter required. Used for steps. After completion of process step (5), i.e. after final strand annealing of the coated precursor at the required final cross-sectional area or final diameter required, a coated wire in the sense of the present invention is obtained.

The precursor object as provided in process step (1) can be obtained by alloying/doping copper with the required amount of silver and, optionally but preferably also with an appropriate amount of phosphorus. The copper alloy itself can be prepared by conventional processes known to those skilled in the art of metal alloying, for example by melting together the required proportions of copper, silver, and optional phosphorus. In doing so, it is possible to use a master alloy. The melting process can be carried out, for example, using an induction furnace, which is suitable to work under vacuum or under an inert gas atmosphere. The materials used may have a purity rating of 99.99% by weight and above, for example. The resulting melt can be cooled to form a homogeneous piece of copper-based precursor object. Typically, such precursor objects are in the form of rods, for example with a diameter of 2 to 25 mm, and a length of, for example, 2 to 100 m. Such rods can be fabricated by casting the copper alloy melt in an appropriate mold, followed by cooling and solidifying.

In process step (2), the precursor object is elongated precursor object until an intermediate cross-sectional area in the range of 5024 to 70650 μm ² and an intermediate diameter in the range of 80 to 300 μm, preferably in the range of 130 to 230 μm are achieved. It is stretched to form. Techniques for stretching a precursor object are known, and are useful in the context of the present invention. Preferred techniques are rolling, swaging, die drawing or the like, among which die drawing is particularly preferred.

In the latter case, the precursor object is drawn in various process steps until the required intermediate cross-sectional area or required intermediate diameter is reached. Such a wire die drawing process is well known to those skilled in the art. Conventional tungsten carbide and diamond drawing dies can be used and conventional drawing lubricants can be used to support the drawing.

Step (2) of the process of the present invention may include one or more accessory steps for intermediate annealing of the elongated precursor object. Such intermediate annealing may be performed, for example, for an exposure time of 0.5 to 1 second, for example at an oven set temperature within the range of 200 to 650 °C. Such intermediate annealing is generally performed by a strand annealing method.

In process step (3), a double-layer coating comprising an inner layer of palladium and an adjacent outer layer of gold is coated over the surface, on the surface of the elongated precursor object obtained after the end of process step (2) It is formed, so as to overlap. Those skilled in the art will ensure that the inner palladium layer and the outer gold layer are within a range of 1.5 to 2.5% by weight compared to the weight of the inner palladium layer and the weight of the outer palladium layer, and It will be understood that the film is deposited so as to fall within the range of 0.09 to 0.18% by weight compared to the weight.

One skilled in the art knows how to calculate the thickness of such a coating on an elongated precursor object, that is, after finally stretching the coated precursor object, to finally obtain a coating of the layer thickness disclosed for embodiments of the wire. . One skilled in the art knows numerous techniques for forming a coating layer of material according to embodiments on a copper alloy surface. Preferred techniques are plating such as electrolytic plating and electroless plating, sputtering, ion plating, deposition of gaseous materials such as vacuum deposition and physical vapor deposition, and deposition of molten materials. In the context of the present invention, electrolytic plating is the preferred technique.

In process step (4), the coated precursor object obtained after completion of process step (3) is further stretched until the required final cross-sectional area or diameter of the wire is achieved. Techniques for stretching the coated precursor object are the same stretching techniques, as mentioned above for the initiation of process step (2).

In process step (5), the coated precursor obtained after completion of process step (4) is, for example, at an oven set temperature in the range of 450 to 650° C. for an exposure time of 0.3 to 1 second, or a preferred embodiment At, 500 to 600° C. for 0.3 to 1 second, finally strand annealed. In an exemplary embodiment, particularly in an exemplary embodiment of a wire having a diameter of about 18 μm, final strand annealing may be performed at an oven set temperature of 530° C. for an exposure time of 0.8 seconds.

In a preferred embodiment, the finally strand annealed coated precursor, ie the still hot coated wire, in an embodiment, may contain one or more additives, for example 0 to 1000 ppm by weight of additive(s), It is quenched in water. Quenching in water is performed immediately or quickly, i.e. within 0.2 to 0.6 seconds, and finally the strand annealed coated precursor is processed in process step (5), for example by dipping or dripping. It means cooling from the experienced temperature to room temperature.

The optional sub-step intermediate annealing of process step (2) as well as the final strand annealing of process step (5) may be carried out in an inert or reducing atmosphere. A number of types of inert atmospheres as well as reducing atmospheres are known in the art and are used to clean the annealing oven. Of the known inert atmospheres, nitrogen or argon is preferred. Of the known reducing atmospheres, hydrogen is preferred. Another preferred reducing atmosphere is a mixture of hydrogen and nitrogen. Preferred mixtures of hydrogen and nitrogen are 90 to 98 volume percent nitrogen and thus 2 to 10 volume percent hydrogen, where the volume percent is a total of 100 volume percent. Preferred mixtures of nitrogen/hydrogen are 93/7, 95/5 and 97/3 volume%/volume%, respectively, based on the total volume of the mixture.

Purging with these types of inert or reducing gas preferably lies within the range of 10 to 125 min ^-1 , more preferably 15 to 90 min ^-1 , most preferably 20 to 50 min ^-1 , Gas exchange rate (= gas flow rate [liter/min]: inside oven volume [liter]).

After process step (5) and optional quenching is completed, the coated wire of the present invention is completed. In order to fully benefit from its properties, it is suitable for wire bonding applications to use immediately, ie without delay, for example within 60 days of standing time after completion of process step (5). Alternatively, to maintain the wide wire bonding process window properties of the wire and to protect the wire from oxidation or other chemical attack, the finished wire is typically immediately after completion of process step (5), ie without delay. , For example, less than 1 hour to 5 hours after completion of process step (5), coiled and vacuum sealed, and then stored for further use as a bonding wire. Storage in a vacuum sealed state should not exceed 6 months. After opening the vacuum seal, the wire must be used for wire bonding within 60 days.

It is preferred that both process steps (1) to (5), as well as cold and vacuum sealing, are performed under clean room conditions (US FED STD 209E clean room standards, 1k standard).

A third aspect of the invention is a coated wire obtainable by the previously disclosed process according to any embodiment of the invention. It has been found that the coated wire of the present invention is well suited for use as a bonding wire in wire bonding applications. Wire bonding techniques are well known to those skilled in the art. In the process of wire bonding, ball bonding (first bonding) and stitch bonding (second bonding, wedge bonding) are formed. During junction formation, a specific force (typically) supported by the application of scrub amplitude (typically measured in μm) or by the application of ultrasonic energy (typically measured in mA) (Measured in grams). In the wire bonding process, a mathematical multiplication of the difference between the upper and lower limits of the applied force and the upper and lower limits of the applied rubbing amplitude, or the difference between the upper and lower limits of the applied force and the upper and lower limits of the applied ultrasonic energy. The mathematical multiplication of the difference between the lower bounds defines the wire bonding process window:

(Upper limit of applied force-Lower limit of applied force) · (Upper limit of applied rubbing amplitude-Lower limit of applied rubbing amplitude) = Wire bonding process window.

or

(Upper limit of applied force-Lower limit of applied force) · (Upper limit of applied ultrasonic energy-Lower limit of applied ultrasonic energy) = Wire bonding process window.

The wire bonding process window satisfies the specification, ie passes the conventional tests such as the conventional tensile test, ball shear test and ball pull test, to name a few. Defines a region of force/rubbing amplitude combinations or force/ultrasonic energy combinations, allowing for the formation of.

In other words, the first junction (ball junction) process window region is the product of the difference between the upper and lower limits of the force used for the junction and the difference between the upper and lower limits of the applied rubbing amplitude, or used for the junction. It is the product of the difference between the upper and lower limits of the force and the difference between the upper and lower limits of the applied ultrasonic energy, and the resulting bonds have specific ball shear test specifications, for example, a ball shear of 0.0085 g/μm ² The second bonding (stitch bonding) process window region, while having to satisfy, for example, no tackiness on the bonding pad, is between the upper and lower limits of the difference between the upper and lower limits of the force used for bonding and the applied rubbing amplitude. Is the product of the difference, or the product of the difference between the upper and lower limits of the force used for the bonding and the difference between the upper and lower limits of the applied ultrasonic energy, and the resulting bonding, for example For example, a tensile force of 2.5 g, no stickiness on the lead, etc. must be satisfied.

For industrial applications, for reasons of robustness of the wire bonding process, it is desirable to have a wide wire bonding process window (force in g versus rub amplitude in μm or force in g versus ultrasonic energy in mA). The wire of the present invention shows a fairly wide wire bonding process window.

The following non-limiting examples illustrate the invention. These examples serve as illustrative descriptions of the invention, and are not intended to limit the scope of the invention or claims in any way.

Examples

Preparation of the airless ball (FAB):

FAB is processed according to the procedures described in the KNS Process User Guide for FAB [Kulicke & Soffa Industries Inc., Port Washington, PA, USA, 2002, May 31, 2009] Became. FAB is a conventional electric flame-off by standard firing (95 vol% nitrogen/5 vol% hydrogen atmosphere, single step, 17.8 μm wire, 50 mA EFO current, EFO time 200 μs). : EFO) It was prepared by performing burning.

Test methods A. to F.

All tests and measurements were performed at T = 20 °C and relative humidity RH = 50%.

A. Linear Intercept Method

The wires were first buried using a cold-mounted epoxy resin, and then polished (cross-treated) by standard metallographic techniques. A multi-prep semi-automatic grinder was used with a low force and optimum speed to grind and polish samples with minimal strain on the sample surface. Finally, the polished sample was chemically etched using ferric chloride to reveal grain boundaries. The average particle size was measured using a linear sectioning method, under an optical microscope with a magnification of 1000, according to the ASTM E112-12 standard.

B. FAB form

The formed FAB was examined by a scanning electron microscope (SEM) having a magnification of 1000.

evaluation:

++, very good (round ball)

+, excellent (round ball);

0, acceptable (not perfectly round, but no apparent flats on the FAB surface);

-, Peach-shaped balls

--, serious peach ball

As used herein, the term "peach ball" means the formation of two flats with distinct hemispheres at the ends of the FAB.

C. Bonded ball shape

The formed FAB was lowered from the predefined height (203.2 μm tip) and speed (contact speed of 6.4 μm/sec) to an Al-0.5 wt% Cu bonding pad. Upon contact with the bonding pad, a set of defined bonding parameters (100 g bonding force, 95 mA ultrasonic energy and 15 ms bonding time) affected the FAB to deform, and formed a bonded ball. . After forming the ball, the capillaries were raised to a predefined height (kink height of 152.4 μm and loop height of 254 μm) to form a loop. After forming the loop, the capillary tube descended into a lead to form a stitch. After forming the stitch, the capillary rose and the wire clamp was closed to cut the wire to create a predefined tail length (tail length extension of 254 μm). For each sample, 5 bonded wires were optically inspected using a microscope with a magnification of 1000.

evaluation:

+, circular;

0, acceptable;

-, flower shape.

D. Off Center Ball (OCB)

The same method as described in Method C was applied, but instead of checking the roundness of the ball, the centricity of the ball was determined. For each sample, 5 bonded wires were optically inspected.

evaluation:

++, perfectly centered;

+, centered;

0, tolerable eccentricity;

-, eccentric;

--, very eccentric.

E. Pd distribution on FAB

FAB was first embedded using cold-mounted epoxy, and cross-treated by standard metallographic techniques. A multi-prep semi-automatic polishing machine was used in the middle with low force and optimum speed to grind and polish samples with minimal strain on the sample surface. Finally, the polished sample was inspected under a high power microscope with a magnification of 1000. For each sample, 5 FABs were optically inspected.

Visual evaluation:

++, Pd covers the FAB sheath very uniformly to have a Pd coverage of 80% or more of the FAB height;

+, Pd evenly covers the FAB envelope to have a Pd coverage of 70% or more of the FAB height;

0, Pd partially covers the FAB sheath to have Pd coverage between 50 and 70% of the FAB height, and partially diffuses into the ball;

-Most of the diffusion of Pd into the ball, with the formation of Cu-Pd alloy, to have Pd coverage of 50% or less of FAB height;

- Most of the diffusion of Pd into the ball, with the formation of Cu-Pd alloy, to have a Pd coverage of 30% or less of the FAB height.

F. Corrosion resistance:

The wires were ball bonded to Al-0.5 wt% Cu bonding pads. The test devices, with the wires so joined, were stored in a highly accelerated stress test (HAST) chamber at a temperature of 130° C., 85% relative humidity (RH) for 96 hours, and later, The number of lifted balls under a low power microscope at 100X magnification (Nikon MM-40) was examined. Observation of a larger number of lifted balls indicated severe interfacial galvanic corrosion. Evaluation was made in terms of ranking:

++, least lifted balls;

+, less lifted balls;

0, middle lifted balls;

-, many lifted balls;

- The most lifted balls;

Example 1: wire Samples 1 to 8

A defined amount of copper, silver and phosphorus, each of at least 99.99% purity (“4N”), was melted in a crucible in a vacuum oven at about 1200°C. Subsequently, a wire core precursor object in the form of rods of 8 mm was continuously cast from the melt. The rods were then drawn in several drawing steps to form a wire core precursor having a circular cross section with a diameter of 200 μm. The wire core precursor was electroplated to have a double layer coating consisting of an 840 nm thick inner palladium layer and a 45 nm thick outer gold layer, and then a 75 nm final palladium coating layer thickness and a 4 nm final gold coating layer. It was further drawn to a final diameter of 17.8 μm to have a thickness, followed by final strand annealing at an oven set temperature of 530° C. for an exposure time of 0.8 seconds, followed immediately by so obtained coated wires at 500 ppm by weight of surfactant. It was quenched in water containing.

By this procedure, several different inventive samples and comparative samples 1 to 9 of palladium and gold coated copper-based wire were prepared. Table 1 shows the composition of the wire cores.

Sample: Wire core composition: 1 (comparative example) Cu doped with 75 weight ppm P 2 (invention) Cu alloyed with 0.1 wt% Ag and doped with 75 wtppm P 3 (invention) Cu alloyed with 0.2% by weight Ag and not doped with P 4 (invention) Cu alloyed with 0.2 wt% Ag and doped with 40 wtppm P 5 (invention) Cu alloyed with 0.2 wt% Ag and doped with 75 wtppm P 6 (invention) Cu alloyed with 0.3 wt% Ag and doped with 75 wtppm P 7 (comparative example) Cu alloyed with 0.4% by weight Ag and doped with 75% by weight P 8 (comparative example) Cu alloyed with 0.5% by weight Ag and doped with 75% by weight P

Yes 2: wire Samples 9 to 10

The wire sample was processed similarly to Sample 5 in Example 1, but the layer thickness of the inner palladium coating and the outer gold coating was changed, as reported in Table 2.

Sample Inner palladium layer thickness (nm) Outer gold layer thickness (nm) 9 (invention) 75 2.3 10 (invention) 68 2.3

Table 3 below shows the specific test results.

Sample: One 2 3 4 5 6 7 8 9 10 FAB form + 0 - - 0 - - - 0 + Bonded ball shape + + + + + + + + + + OCB + + + + + - - - - - Pd distribution on FAB - - + + + + ++ ++ + 0 Corrosion resistance - 0 + + + + ++ ++ + 0

Claims (14)

A coated wire comprising a wire core having a surface, the wire core having a coating layer superimposed on its surface, the wire core itself:
(a) silver in an amount of 0.1 to 0.3% by weight,
(b) copper in an amount in the range of 99.64 to 99.8825% by weight,
(c) phosphorus in an amount ranging from 0 to 100 ppm by weight, and
(d) Additional components in amounts ranging from 0 to 500 ppm by weight (different components from silver, copper and phosphorus)
It includes,
The individual amount of any additional component is less than 30 ppm by weight,
All amounts in weight percent and ppm by weight are based on the total weight of the core, and
The coating layer is a double-layer comprising an inner layer of palladium and an adjacent outer layer of gold,
The weight of the inner palladium layer is within the range of 1.5 to 2.5% by weight, compared to the weight of the wire core, and
The weight of the outer gold layer is in the range of 0.09 to 0.18% by weight, compared to the weight of the wire core, the coated wire. According to claim 1,
The amount of silver is 0.2% by weight, coated wire. The method according to claim 1 or 2,
The amount of phosphorus is 50 to 100, or 70 to 80 ppm by weight of the coated wire. The method according to claim 1 or 2,
The amount of additional components is 0 to 100 ppm by weight, coated wire. The method according to claim 1 or 2,
Coated wire having an average cross-sectional area in the range of 50 to 5024 μm ² . The method according to claim 1 or 2,
Coated wire having a circular cross section having an average diameter in the range of 8 to 80 ㎛. The method according to claim 1 or 2,
Wire core,
(i) the average wire particle size measured in the longitudinal direction is 3 to 6 µm,
(ii) the ratio of the average particle size and the diameter of the wire core measured in the longitudinal direction is within the range of 0.05 to 0.25,
(iii) The standard deviation ratio (RSD) of the average particle size to the average particle size of the core measured in the longitudinal direction is within a range of 0.1 to 0.4,
The coated wire, characterized by at least one of the intrinsic properties of. A process for manufacturing the coated wire of claim 1 or 2, at least:
(1) providing a precursor object of the desired composition, the precursor object comprising: silver in an amount of 0.1 to 0.3% by weight, copper in an amount in a range of 99.64 to 99.8825% by weight, an amount in a range of 0 to 100 ppm by weight Of phosphorus, and additional components in amounts ranging from 0 to 500 ppm by weight (different components from silver, copper and phosphorus), the individual amounts of any additional components being less than 30 ppm by weight, in weight percent and ppm by weight Providing a precursor object, all amounts of which are based on the total weight of the precursor object,
(2) stretching the precursor object to form an elongated precursor object until an intermediate cross-sectional area in the range of 5024 to 70650 μm ² and an intermediate diameter in the range of 80 to 300 μm are achieved,
(3) depositing a double-layer coating of the inner layer of palladium and the adjacent outer layer of gold on the surface of the elongated precursor object obtained after completion of the process step (2), wherein the weight of the inner palladium layer is Double-layer, such that it lies within the range of 1.5 to 2.5% by weight compared to the weight of the stretched precursor object, and the weight of the outer gold layer lies within the range of 0.09 to 0.18% by weight compared to the weight of the stretched precursor object. Depositing a coating,
(4) further stretching the coated precursor object obtained after completion of process step (3) until the required final cross-sectional area or diameter is achieved, and
(5) The coated precursor obtained after completion of the process step (4), finally at an oven set temperature in the range of 450 to 650° C. for an exposure time within the range of 0.1 to 3 seconds to form a coated wire, finally Strand annealing,
Manufacturing process of the coated wire comprising a. The method of claim 8,
The step (2) comprises one or more accessory steps for intermediate annealing of the stretched precursor object, the coated wire manufacturing process. The method of claim 8,
The final strand annealing is performed at an oven set temperature of 500 to 600° C. for an exposure time of 0.3 to 1 second, the coated wire manufacturing process. The method of claim 8,
The finally strand annealed coated precursor is immersed in water that may contain one or more additives, the coated wire manufacturing process. The method of claim 8,
The final strand annealing of process step (5) is performed under an inert or reducing atmosphere, the coated wire manufacturing process.
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