Gold wire bonding (also known as gold wire bonding) uses wafer-thin gold wires (approx. 15-75 µm thick) to create electrical connections between a microchip and the housing (lead frame) of a printed circuit board. It is the standard procedure for connecting integrated circuits to the outside world.

Gold offers decisive advantages: It is extremely corrosion-resistant (it does not oxidise), can be easily deformed even at very low forces and temperatures and offers excellent electrical conductivity. This makes the connection extremely reliable and durable.

The process is thermosonic. This means that a combination of heat (usually between 150°C and 250°C), ultrasound and pressure is used. The gold wire is passed through a needle (capillary). A ball is melted at the end of the wire using a flame or spark, which is then pressed onto the chip connection (pad). The second connection (to the housing) is then made as a wedge bond.

Yes, common alternatives are copper or aluminium wires. Copper is cheaper and has better electrical conductivity, but is harder and requires more energy for bonding. Aluminium is often used for power applications. Despite its higher price, gold is mainly used where maximum reliability is required or the chip pads are very sensitive, as the bonding process with gold is particularly gentle on the material.

Gold wire bonding is typically used in high-frequency technology, aerospace, medical technology and automotive applications. It is ideal for all assemblies that have to withstand extreme temperature fluctuations or where failure due to corrosion must be avoided at all costs (e.g. in LED modules, sensors or high-performance processors).

It is often visible to the naked eye: white spots or blistering between the layers, especially after soldering. In severe cases, the circuit board bulges visibly (blistering). A gap between the copper and the base material can be recognised microscopically.

As a rule, no. Once the material bond has been destroyed, the adhesion cannot be restored. The affected circuit board must be regarded as scrap and replaced.

Standard FR4 is susceptible if it has been exposed to moisture and extreme temperature peaks. High-Tg materials (higher glass transition temperature) or polyimide are significantly more resistant to thermally induced delamination.

Both terms are often used synonymously, but describe different degrees of severity. Delamination refers to the separation of the layers on the inside. Blistering is the visible manifestation of this - i.e. the formation of bubbles on the surface or between the layers.

The most important step is pre-baking the PCBs before soldering to remove any trapped moisture. In addition, the specified temperature profile of the circuit board should be adhered to exactly in order to avoid thermal shock.