New laser diamond tools for machining ceramics and semiconductor materials

Dr. John Patten, a professor of manufacturing engineering at Western Michigan University, has developed a micro-laser-assisted processing technology called "μ-LAM", which combines lasers with diamond tools to heat, soften and cut silicon semiconductors and ceramic materials.

John Patten said, "These materials are usually very brittle and tend to break easily if you try to deform or process them. By softening these materials, we can increase their flexibility and make them easier to process."

The μ-LAM processing device integrates an infrared fiber laser (wavelength range 1000-1500nm). The laser beam is irradiated to the workpiece through a single-point diamond tool with high optical clarity, heating the workpiece material to more than 600℃. The diamond tool with a tip arc radius of 5μm-5mm is connected to a laser mounted in a tungsten or carbide housing by epoxy bonding (suitable for milliwatt laser power processing) or welding/brazing (suitable for 1 watt or more laser power processing).

Other engineers have tried various different methods to process brittle materials (such as ceramics). One method is to heat the workpiece in a furnace before processing it; the other method is to use laser heating and diamond tool cutting separately. The method invented by Patten integrates the laser and diamond tool together, so it has obvious advantages. He explained, "Things are simpler because the laser and the tool are aligned, and the laser heating is just at the cutting edge of the tool, so the best processing effect can be obtained. In addition, the workpiece material will not be overheated."

Patten said that μ-LAM processing technology can also reduce processing time and processing costs, and obtain very smooth optical surfaces. "Using conventional processing methods, if you want to make an optical element (such as a reflector), you usually need to start with a cast workpiece blank, and then go through a series of processing steps: rough grinding, fine grinding, and grinding before you can finally form it. Our processing method replaces the original series of processes, cutting with a single-point diamond tool on a CNC machine tool, and can also obtain excellent surface roughness (Ra1-10nm)."

Patten is working with a Japanese company to achieve commercial application of the μ-LAM system. He expects that the invention will find its way into a number of industries, including the automotive, aerospace, medical equipment, semiconductor and optical industries. "Our initial goal was to target the optical and semiconductor industries, but now it seems that most of its applications will be in high-energy, high-temperature microelectronic devices," he said. "In the semiconductor industry, silicon wafers are the carriers of chips and integrated circuits, and under high-temperature working conditions, people will use silicon carbide. Therefore, now almost all of our energy is focused on the processing of silicon carbide."