As the Internet of Things (IoT) grows, high-reliability electronics manufacturing is becoming increasingly important. Customer expectations around device performance and versatility are rising. In response to this trend, manufacturers must address error-prone processes like wire bonding techniques.
Wire bonding is a critical step in producing small electronic devices. Like many high-precision processes, though, it’s easy to do poorly.
The Importance of Wire Bonding for Modern Electronics
The average U.S. household hosts 22 connected devices and people will likely own more in the future. This rising demand means two things for high-reliability electronics manufacturing. First, manufacturers must increase output to keep up. Secondly, they must ensure their devices remain functional in various environments.
Electronics must withstand more extreme conditions, but consumers will also want highly functional, feature-rich devices. Poor wire bonding stands in the way of that goal. Suboptimal bonds could cause wires to lose connections or connect to the wrong terminal. Alternatively, they could fail to separate circuits, leading to electromagnetic interference.
Wire bonding can introduce operational roadblocks, too. Higher demand may force manufacturers to emphasize production speed, but going too quickly can make bonding errors more likely. Similarly, if wire bonding techniques produce more mistakes, manufacturers will lose time and money to defects and rework.
Wire Bonding Techniques to Consider
Proper wire bonding techniques ensure manufacturers provide higher-quality devices while maintaining production efficiency. Here are a few innovative ways you can achieve that goal.
Consider Alternate Materials
Optimizing wire bonding starts with using the right materials. Conductivity and cost are the most prominent factors, but selection shouldn’t end there. It’s also important to evaluate how materials work with different wire bonding techniques and what environmental restrictions they may require.
Copper is extremely conductive and cost effective, but it’s also prone to corrosion. A more corrosion-resistant material would make the bonds more resilient and enable more quality control in manufacturing. Electrostatic discharge is less likely at humidities above 40%, so manufacturers could increase humidity to prevent errors without risking corrosion.
Some materials also enable niche bonding methods. Gold-gold connections can use compliant bonding, which uses lower temperatures, thus reducing operating costs. In some production lines, those savings may be enough to make gold more cost effective than copper or aluminum.
Clean Surfaces Before Bonding
High-reliability electronics manufacturing also relies on clean surfaces. PCB cleanliness may not initially seem like a leading concern, but any contamination on the wire or die will jeopardize the bond’s adhesion.
Regardless of which wire bonding techniques you use, you must ensure the components are contaminant-free. Getting rid of dust with compressed air isn’t enough, either. Plasma surface treatment is an ideal alternative, as it removes microscopic contaminants without damaging or removing bonding material.
Your bonding method can affect cleanliness, too. Insufficient power in ultrasonic bonding processes may fail to remove lingering contaminants, weakening the bond. All machines in the cleaning, treatment and bonding process must be carefully calibrated to ensure they deliver optimal power.
Utilize Laser Bonding
Most bonding processes use thermocompression or ultrasonic bonding. While these methods have proven track records, newer alternatives offer more precision and efficiency. Laser bonding is among the most promising of these innovations.
Laser welding is technically not a wire bonding technique but rather an alternative, though it serves the same purpose. Unlike thermocompression and ultrasonic methods, laser bonding doesn’t rely on physical pressure or mechanical force. It uses only heat to bond materials, preventing errors from misalignment or improper power.
Laser bonding is also highly precise and you can laser weld multiple bonds simultaneously. While this approach does require pre-treatment, the laser’s higher efficiency may make up for the extra step. Remember — you must also calibrate lasers like a physical bonding machine or you’ll risk damaging components through excess heat.
Choose the Right Protection Method
There are also opportunities to ensure high bond reliability after the bonding process. Every wire bonding technique also requires protection of the wire and die. If you use an insufficient method, it could raise costs and jeopardize bond strength, but the opposite is also true.
Lid-and-cover protection provides the most resilient defense but is also the most expensive. As such, it’s best to reserve it for highly sensitive components or devices that must withstand rugged conditions. Many common insulators carry static charges, so choose covers carefully to avoid electrostatic discharge.
For most applications, glob-top protection or dam-and-fill methods are the most cost effective. Simple glob-top protection is fast and affordable, but the harder barrier dam-and-fill provides may offer more reliable protection. Consequently, the latter is generally preferable for high-reliability electronics manufacturing.
Automate Quality Inspections
Another way to boost wire bond reliability after the bonding process is to refine your quality control. It’s almost always best to automate quality inspections — at least in part — because artificial intelligence (AI) is faster and more accurate than human inspectors.
Machine vision systems can scan PCBs in fractions of a second to find bonding defects. Because they can’t get distracted or tired, they’ll provide the same accuracy with every scan. That speed and reliability will ensure you don’t have to sacrifice product quality to meet rising throughput demands.
The other advantage of automation is it provides data-driven insights over time. Smart manufacturing equipment reveals where problems originate, informing more effective process changes. You can then adapt to remove error-prone steps in your wire bonding techniques to improve reliability and cost-effectiveness.
High-Reliability Electronics Manufacturing Needs Wire Bonding
As end users become more accustomed to better-functioning devices, all device production will fall under high-reliability electronics manufacturing. Wire bonding is far from the only process to refine in support of that shift, but it’s a crucial one. There’s too much that can go wrong too easily to ignore this workflow.
These five strategies will make your wire bonding techniques more reliable, no matter what kinds of products you manufacture. You’ll make fewer errors and create more resilient devices, all while reducing production costs and increasing output. These changes will prove essential in keeping up with modern consumers’ rising demands.