Choosing the Right Wire Bonder to Meet Your Production Challenges

Wire bonding is a commonly used technique in the manufacture of semiconductor and electronic assemblies, allowing the creation of reliable electrical connections between device and substrate. This process, which uses metallic wires to establish connections, is ubiquitous in the microelectronics and power semiconductor industries, and is now also commonplace in Lithium-Ion battery pack assembly.

Applications can be broadly categorised as follows:

  • Fine wire for signal applications connecting chips to substrates.
  • Heavy wire for connections requiring high currents such as power semiconductor devices, with wires of more than 75 µm in diameter.
  • Heavy wire for connections requiring very high currents such as Lithium-Ion battery pack, with wires of typically 500 µm in diameter.

 

wire bonding wire thickness

 

Many other applications exist such as stud bumping for flip chip applications or using wires for their mechanical properties rather than for electrical connections; here we focus mainly on the more common place requirements.

Wire materials can be varied. Aluminium (Al), gold (Au), or copper (Cu) are the most common however other materials such as platinum or coated wires exist.

For fine wire applications, connections are formed using “wedge” or “ball” bonding technology. The selection can be determined by the application such as bond pad & size or whether elevated temperatures are permissible. It can sometimes be purely customer preference, perhaps based on prior experience of one technology over the other.

Wire bonding machines can broadly be divided into three main categories: manual, semi-automatic, and automatic; each meeting specific requirements in terms of flexibility, production volume, precision, and cost.

Accelonix offers a wide range of wire bonders across these categories, from the fully manual TPT HB05 through to the most automated Hesse Bond Jet platforms. Choosing the right equipment is essential for any customer. Accelonix’s experience and guidance will ensure that you are able to make an unbiased, informed selection that maximise your production efficiency and quality. Understanding the specific applications and advantages of each type of wire bonder ensures that our customers can make the smart decision, selecting a system perfectly aligned with their production requirements.

In this article, we guide you through the different options and criteria to consider when choosing a wire bonder that best meets your production challenges. Whether you are developing R&D concepts in low volume, producing a broad mix or parts in medium quantities, or many tens of thousands of a single part, the wire bonding requirement must still be carefully considered.

A single part may have complex wire bond looping geometries that will be difficult to consistently achieve manually even if the quantities are low. Similarly, a part may require only a simple single wire bond that is comfortably achieved on a manual system, even though quantities may be relatively high. The application(s), operating environment, volumes, automation requirements and your future plans must all be considered. This guide will help you navigate the many options available within our equipment portfolio and support your understanding of the varied world or wire bonding equipment.

Flexibility and Adaptability: Use in R&D Environments and Small Productions (Manual)

Manual wire bonding can be ideal for many research and development (R&D) applications as well as for production environments where wire bond counts are low and looping geometry is less demanding. This method is perfect for prototypes and small runs, offering great ease of use and the ability to make precise adjustments in real-time. The welding process is automatically controlled by the machine (pressure, power, time), thus ensuring weld repeatability. Looping is controlled by the user, providing a level of real time control and operator interaction not available with automatic platforms.

Example: An R&D lab developing a new prototype of an electronic sensor requiring 17 µm gold wires with a “ball” bonding process. Often, the samples are “hand crafted” and not necessarily in pristine condition. Each sample may have variations in visual appearance, metallisation may be scratched through many manual handling stages, epoxy may have contaminated areas of the top surface of the die. Engineers may need to adjust bonding parameters and bond position on a per bond bases to compensate for these defects.

With a manual wire bonder like the HB05 Wedge Bonder & Ball Bonder, they can quickly modify bond parameters as needed and navigate around the die to form the necessary connections despite metallisation issues and contamination. This flexibility allows users to experiment more efficiently and bond even simple product that would be challenging for more sophisticated systems.

 

R & D wire bonding

 

Additionally, this type of equipment can be particularly suitable for teams where multiple users require occasional access to wire bonding equipment. These platforms require minimal user training to operate, and recipes can be stored for easy retrieval as required.

Manual wire bonding can also meet the needs of low wire count production. For example, a manufacturer of devices with only a few easily placed wire bonds can build relatively high quantities of product utilising one of more TPT HB05 Wedge & Ball Bonders. The manual nature of the process allows for easy compensation of product variability such as die positional accuracy and with experience, operators can achieve very consistent looping and modest bonding speeds.

HB05 Wedge & Ball Bonder: Designed for manual bonding of fine wires in ball and/or wedge configurations, offering bonding capabilities for gold and aluminium wires from 17 µm to 75 µm and ribbons up to 25 µm x 250 µm. Equipped with a 4.3-inch TFT screen, it allows precise adjustment and easy use.

Medium Volume Production: Environments Requiring Operational Flexibility and Repeatable Production (Semi-automatic)

Semi-automatic wire bonding is perfect for environments that require higher consistency and / or higher wire bond counts. These systems introduce more automation while maintaining operational flexibility. Motorisation of one or more axes, eases the workload on the user and helps to eliminate loop to loop variability and variability between operators.

Example: A company specialising in the manufacture of chips on PCBs for a control circuit with aluminium wire bonding of 25 µm. They typically produce 1000 units a week, each unit requiring 10 wire bonds. This work is distributed across a number of operators.

Using a semi-automatic wire bonder like the HB16 Wedge & Ball Bonder, the company can set the bonding parameters to ensure optimal repeatability regardless of operator or shift. The 6.5-inch TFT touch screen and the capacity to store 100 programs allows the engineering team to develop and store recipes to suit many product variants which can simply be implemented in production.

Consistency is critical in production and the semi-automatic nature of the TPT HB16 helps to ensure that every part is wire bonded with the same process. More advanced features such as automatic wire feed further support repeatability by minimising drag on the wire during the loop forming process.  A new user to the TPT HB16 can, with the simple press of a button, create an identical wire bond to an experienced user of many years.

 

 

Additionally, the looping control provided by the TPT HB16 Wedge & Ball Bonder can be extremely valuable in the production of RF devices where it is necessary to standardise loop shapes to control inductance. The motorised Z and Y axes allow for precise movement control, ensuring consistent bond heights and lengths, while allowing easy adjustments based on customer specifications or design changes.

HB10 Wedge & Ball Bonder: Designed for semi-automatic bonding of fine wires in ball and/or wedge configurations, with a motorised Z-axis, a 6.5-inch TFT touch screen, and the capacity to store 100 programs.

HB16 Wedge & Ball Bonder: Ideal for semi-automatic bonding in ball and/or wedge configurations with motorised Z and Y axes, offering advanced features such as automatic loop control.

Power Applications: R&D Environments and Small Productions

Though similar to the operation of fine wire machines, power application wire bonders are adapted with increased ultrasonic power and bonding force to handle wires up to 600 µm diameter. Due to the thicker, stronger wire, the bond head is also configured with a “wire cutter” assembly to cut the wire after the second bond.

Example: A company specialising in the recycling and repair of power electronic modules. They regularly receive small batches of a variety of different parts. Using a semi-automatic wire bonder like the TPT HB30 Wedge Bonder, the company can quickly adapt its work to replace power wires directly on the chips and internal connectors of the module. Manual control allows flexibility in bond placement, catering for the additional complications of reworked assemblies.

The 6.5-inch TFT touch screen and the capacity to store 100 programs allow operators to quickly adjust settings and switch from one batch to another without loss of efficiency. The motorised Z-axis adapts to different products and heights.

HB30 Wedge Bonder – Heavy Wire: Ideal for semi-automatic bonding with motorised Z and Y axes, offering advanced features such as automatic looping control and wire cutter.

Repeatability and Consistency: R&D Environments and Low Volume Production with Higher Bond Count

For applications requiring many wire bonds, the HB100 is equipped with motorised Z, X, Y, and Theta axes. The operator places the piece in the active area, identifies the alignment points with the camera, and then starts the automatic bonding programme.

Example: A company producing 1000 units of a multi-chip package that contain a number of different die, each with their own wire bond layout. Applications such as this are extremely demanding for even semi-automatic wire bonders, requiring great skill from the machine operator and the need for multiple recipe selections per package as each unique die is navigated. Inevitably, there is an increased risk of error and operator to operator variability.

The HB100 allows for higher throughput whilst maintaining consistent welding and looping profiles from package to package. Also, thanks to easy programming and operation, it is a very accessible machine, simplifying its integration into the production environment and greatly reducing the likelihood of operator error.

HB100 Wedge & Ball Bonder: Ideal for automatic bonding with motorised Z, X, Y, and Theta axes. Designed for small-scale production of circuits requiring a large number of connections.

Industrial Scale Production: Environments where Precision, Repeatability, and/or Speed are Important

Complete automation can enable near continuous bonding, moving from one product to the next without operator intervention thanks to automatic product conveyance. However, often it is the added sophistication embedded within industrial wire bonders rather than speed that drives the decision for their purchase. Industrial wire bonders incorporate multiple sensors that provide real time monitoring of key characteristics, such as wire deformation and transducer current.

These technologies enable finer control of the welding process and monitoring of numerous quality measures that can be used to provide qualitative feedback on the bonding process. Traceability is particularly sought after in high-quality applications such as aerospace, automative and medical electronics and as such, this requirement is often a driver for the purchase of an industrial wire bonder. Their speed is simply an added bonus!

Example: An aerospace manufacturer producing 1k units per year with aluminium wires of 25 µm. Using an automatic wire bonder like the Bondjet BJ855 with automation tailored to their products, the company can guarantee precision and reliability with complete traceability, regardless of the complexity of the wire bond layout. This bonder offers bonding capabilities for aluminium, gold, and copper wires from 12.5 µm to 75 µm, and ribbons up to 250 µm x 25 µm. Optimised pattern recognition and Hesse assistance tools ensure reliable and consistent production regardless of production scale.

Bondjet BJ855: Designed for automatic bonding of fine wires, with bonding capabilities for aluminium, gold, silver, copper, and platinum wires from 12.5 µm to 75 µm, and ribbons up to 250 µm x 25 µm.

 

 

Example: A company manufacturing battery modules each with 364 cylindrical cells, requiring multiple connections between the batteries and bus bars using 500 µm aluminium wires. Using the Bondjet BJ985, the large packs can be full accommodated, and the wire bonds placed fully automatically without intervention thanks to the machine’s large construction.

Furthermore, utilising advanced features such as machine vision, automated pull test and similar associated quality tools, each wire bond is automatically and accurately placed while wire bond reliability can be monitored, and the user alerted to any issues relating to faulty pack construction or contamination.  The bonding process is carried out in a clean and secure environment, without risk of contamination.

Bondjet BJ985: Allows for high-reliability production with large diameter wires and great flexibility, particularly for large-scale applications (active area: 370×870 mm). It can handle aluminium and copper wires up to 600 µm and ribbons up to 2000×400 µm.

 

 

 

Choosing the right wire bonder is essential to maximise the efficiency and quality of your production. Whether you are in academia or R&D, a medium-sized enterprise, or a large production company, Accelonix is your ideal partner to guide you through this selection process.

Advice and Recommendations: Our experts are here to analyse your specific needs and recommend the most suitable machines, whether for manual, semi-automatic, or automatic applications.

Support and Assistance: With Accelonix, you benefit from continuous technical support, from installation to maintenance, ensuring that your equipment operates at its best.

Personalised Recommendations: By contacting Accelonix, you will receive tailored recommendations to optimise your production processes and ensure the reliability and precision of your electronic connections.

For personalised advice and top-tier technical support, trust Accelonix. Contact us today to discuss your needs and discover how we can help you achieve your production goals.

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Tel: +44(0)1223 659965

sales@accelonix.co.uk

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