Copper Bonding Wire for Semiconductor Packaging

Copper bonding wire connects die pads to lead frames or package substrates, suitable for IC, LED, and discrete device packaging. Compared to gold wire, copper offers cost advantages, excellent electrical and thermal conductivity, and higher mechanical strength-making it ideal for gold wire replacement and cost optimization in high-volume packaging.

Chalco supplies bare copper, coated copper, and specialty copper-based bonding wires, covering standard fine wires and power-device-grade products. Leveraging capabilities in vacuum melting, multi-stage fine drawing, protective atmosphere annealing, precision spooling, and real-world bonding validation, we match products to your current specifications, package design, wire bonder equipment, and reliability requirements-supporting sample testing, alternative supplier evaluation, and volume ramp-up. Standard fine wires range from 18–50 μm; special thick wires and copper alloy products are available upon project-specific confirmation.

Available Copper Bonding Wire Types

Our copper-based bonding materials fall into three categories: bare copper, coated copper, and specialty copper-based bonding wires-addressing cost optimization, oxidation resistance and process stability, and high-strength, high-current, or specialized reliability packaging needs, respectively.

Bare Copper Bonding Wire

Bare copper bonding wire features high conductivity, low resistivity, and cost efficiency. Available in various diameters, BL, EL, and mechanical conditions for IC, LED, and discrete device packaging.

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• High-purity copper core: supports stable electrical interconnects and low-resistance requirements
• No surface coating: suitable for production lines with mature protective gas environments and established bare copper bonding processes
• Adjustable mechanical properties: BL, EL, and hardness can be tailored to match loop profile, pad structure, and bonding process
• Ideal for high-volume packaging: suited for projects focused on material cost, continuous production, and alternative supplier assessment

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4N/≥4N High-Purity Copper Wire

3N Copper Alloy Wire

2N Copper Alloy Wire

Coated Copper Bonding Wire

Coated copper bonding wire combines the cost and conductivity benefits of copper with enhanced oxidation resistance, storage stability, and consistent bonding performance-ideal for applications requiring wider process windows and higher packaging reliability.

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• Oxidation protection: reduces surface oxidation of the copper core
• More stable bonding: improves first bond (FAB) and second bond performance
• Balanced cost-performance: retains copper's conductivity and cost advantages
• Suitable for high-reliability packaging: enhances storage life, corrosion resistance, and long-term stability

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Pd Coated Copper Wire

Au-Pd Coated Copper Wire

PCAR High-Reliability Copper-Based Bonding Wire

Specialty Copper-Based Bonding Wire

Specialty copper-based bonding wires are designed for power devices, high-current interconnects, and packages requiring high mechanical reliability. They can be matched by wire diameter, alloy system, and mechanical properties.

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• High-current interconnects: larger diameters support higher current capacity
• High mechanical strength: improves tensile strength and loop stability
• Tunable performance: diameter, hardness, and BL/EL can be customized
• Specialized packaging compatibility: suitable for power devices and high-stress interconnects

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Copper Bonding Wire Specifications

Our copper-based bonding wires include bare copper, coated copper, and specialty copper alloy systems, customizable by material purity, surface structure, diameter, mechanical condition, and packaging requirements. Specific parameters vary by product series and are detailed in corresponding model datasheets.

Product Type: Bare copper, coated copper, specialty copper-based wire

Material: High-purity copper or copper alloy

Surface Structure: Bare, Pd-coated, Au-Pd-coated

Mechanical Condition: Standard, soft, high-strength

Fine Wire Diameter: 18–50 μm for CP/CS 4N copper wire

Power Wire Diameter: 5–20 mil for selected power-device copper wire

Customization: Diameter, BL, EL, hardness and winding format

Copper Bonding Wire Technical Parameters

The following parameters are based on CP (standard hardness) and CS (soft condition) 4N bare copper bonding wires referenced in documentation. Both have 99.99% copper content with total impurities below 0.01%. Mechanical properties for other copper-based products depend on specific models.

Mechanical Properties:

Physical Properties:

Wire diameter, breaking load, elongation, mechanical condition, and spooling format can be matched to your current specifications, package structure, and bonding process requirements. Final parameters are subject to product model and technical confirmation.

Copper Bonding Wire Advantages

• Made from 99.99% high-purity copper, offering excellent electrical and thermal conductivity along with material cost savings-ideal for gold wire replacement in high-volume packaging.
• Available in CP standard and CS soft variants, covering 18–50 μm diameters, with BL and EL tailored to pad design, loop profile, and bonding process.
• Controlled mechanical properties support low-loop, long-loop, and fine-pitch bonding while enhancing wire stability during molding.
• Backed by fine drawing, protective atmosphere annealing, precision spooling, and real-world bonding validation-to enable specification matching, sample testing, and volume production ramp-up.

Copper Bonding Wire Applications

Copper bonding wire is used in IC, LED, and discrete device packaging. The appropriate product type and mechanical properties should be selected based on package design, pad metallization, wire diameter, and reliability requirements.

IC Packaging

Suitable for lead-frame-based IC packages such as DIP, SIP, SOP, SOIC, QFP, QFN, and DFN-including analog ICs, control ICs, power management ICs, and consumer electronics components.

LED Packaging

Applicable to LED packages already using copper wire or seeking to reduce gold wire material costs. Selection must consider chip pad metallization, loop geometry, and reliability requirements.

Discrete Device Packaging

Used in TO, SOT, SOD packages for internal interconnects of diodes, transistors, rectifiers, and certain MOSFETs.

Automotive and Industrial Electronics

Applicable to select sensors, driver ICs, industrial control chips, and automotive electronic components-with specialized selection and validation based on temperature, humidity, lifetime, and batch traceability requirements.

Copper bonding wire selection must account for pad metallization, package structure, loop profile, and wire bonder compatibility. Chalco provides specification matching and sample validation based on your current wire diameter, breaking load, elongation, and equipment conditions.

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Comparison of Bare Copper and Palladium-Coated Copper Bonding Wires

Bare copper bonding wire is better suited for projects focused on material cost reduction and already equipped with mature copper wire bonding processes. Palladium-coated copper bonding wire improves oxidation resistance and process stability through its surface palladium layer, making it more suitable for high-reliability packaging applications requiring stringent storage, continuous bonding, and long-term reliability.

When to Choose Bare Copper Bonding Wire: Bare copper bonding wire is ideal for projects primarily targeting material cost reduction and already equipped with mature copper wire bonding capabilities and controlled forming gas environments. It is particularly well-suited for high-volume packaging of standard ICs, LEDs, and discrete devices, and can be easily matched to existing specifications for rapid integration.

When to Evaluate Palladium-Coated Copper Bonding Wire: Consider palladium-coated copper bonding wire when your project prioritizes oxidation resistance, post-opening stability, FAB formation, second bond performance, wider process windows, or higher reliability-especially in automotive electronics and other stringent packaging applications.

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Copper Bonding Wire Production and Customization Capabilities

Chalco offers a complete production capability-from raw material melting and casting, multi-stage fine drawing, protective atmosphere annealing, to precision spooling and surface coating-and can tailor copper-based bonding wire solutions to match your package design, wire bonder, and current product specifications.

Full Manufacturing Capability: Covers melting/casting, coarse and fine drawing, annealing, coating, spooling, and final packaging.

Precise Diameter Control: Offers standard fine copper wires as well as thicker wires for power devices.

Mechanical Property Tuning: Can adjust diameter, breaking load, elongation, and temper (hard/soft condition).

Multiple Material Systems: Supports bare copper, palladium-coated copper, gold-palladium coated, and specialty copper alloy wires.

Custom Spooling Specifications: Can match spool type, winding pattern, and payout requirements to your wire bonding equipment.

Copper Bonding Wire Quality Control

Chalco implements quality control across material composition, dimensional accuracy, mechanical properties, electrical performance, and actual bonding behavior to ensure batch consistency and full traceability.

• Chemical composition, purity, and impurity analysis
• Diameter, surface finish, and spooling quality inspection
• Breaking load, elongation, and hardness testing
• Electrical resistivity and related electrical property verification
• FAB ball shape and bond pad appearance inspection
• Pull force, ball shear strength, and overall bonding performance validation

To minimize risks associated with new material introduction, we can supply copper bonding wire samples matched to your current wire diameter, breaking load (BL), elongation (EL), spool type, and package requirements for equipment compatibility, bond quality, loop profile, pull strength, and continuous bonding tests. Engineering or volume production batches are confirmed only after successful validation.

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FAQ

Can copper bonding wire replace gold bonding wire?

Copper bonding wire can substitute gold wire in certain IC, LED, and discrete device packaging applications to reduce material costs. However, direct parameter-for-parameter replacement is not recommended. Sample validation is required, considering chip pad metallization, package structure, wire diameter, bonder type, and reliability requirements.

What's the difference between standard and soft temper copper bonding wire?

Standard temper copper wire offers higher mechanical strength, which helps maintain stable loop profiles. Soft temper copper wire provides greater flexibility and elongation, making it better suited for applications sensitive to pad stress or requiring fine loop adjustments. Selection should consider breaking load, elongation, pad structure, and bonding parameters together.

Does bare copper wire bonding require forming gas?

Yes, bare copper wire typically requires a controlled forming gas atmosphere during FAB formation to minimize oxidation at the wire tip, which can affect ball shape and bond stability. The specific gas type, flow rate, and EFO parameters should be optimized based on your wire bonder, capillary, and copper wire grade.

What wire diameters are available for copper bonding wire?

Standard CP and soft temper CS 4N bare copper bonding wires are commonly available in 18–50 μm (0.7–2.0 mil). Coated copper wires, thick wires for power devices, and specialty copper alloy wires have different diameter ranges, which can be confirmed based on your specific package and current-carrying requirements.

Can you provide copper bonding wire samples for testing?

Yes. Upon receiving your current wire type, diameter, breaking load, elongation, spool specification, package type, and wire bonder details, we can supply matched samples for FAB formation, bond quality, loop profile, pull strength, and continuous bonding performance validation.

Request Copper Bonding Wire Selection Support or Quotation

Please share your package type, wire bonder model, current bonding wire material (or target performance requirements). Chalco can recommend the optimal solution-whether bare copper, soft temper copper, palladium-coated copper, or specialty copper alloy-based on your package design, cost targets, oxidation resistance needs, and reliability criteria, and support sample testing through to volume supply.

• Package Type and Target Devices
• Current Bonding Wire Material or Part Number
• Wire Diameter, Breaking Load (BL), Elongation (EL), or Target Mechanical Properties
• Wire Bonder Model and Spool Specifications
• Required Sample Quantity or Estimated Annual Volume