Increasingly, new materials are being used in power electronics applications or in radar, 5G and satellite communications. This is leading to an increased demand for gallium nitride (GaN) ceramic substrates for the production of components. Although GaN ceramics are an alternative to silicon, the material is challenging for conventional material processing because it is usually coated with micrometer-thin metal layers, usually gold. Given the very different properties of gold and ceramic materials, conventional processing involves cutting the ceramic substrate and etching the metal layers in two separate steps. However, there are also machine solutions that can quickly process both layers in a single non-contact, chemical-free process.
These are laser cutting systems that meet or exceed tolerances of conventional manufacturing steps without the need for final cleaning of the material. The result is shorter processing times for small series or single samples. An important aspect of laser cutting is its efficiency and accuracy. The operator can carefully adjust and optimise the laser energy for specific materials. The first step involves cutting the desired outline in the ceramic using high-power, high-pulse laser bursts, with the upper gold layers serving as protection against accumulated heat and ejected plasma. The laser pulses provide both the highest processing speed and the lowest thermal stress on the surrounding material, the so-called “cold ablation regime”. Cracks and chips in the ceramic are practically non-existent.
After cutting the ceramic, the substrate is secured by a vacuum table, while the laser power is reduced and adjusted to remove the upper gold layer. By using an airflow chamber and ultra-short pulsed ablation (which ejects very small particles), the laser allows a process without leaving any residue.
Do you have questions regarding this matter?
Your contact person: Lars Führmann
company: LPKF Laser & Electronics AG