Electronic devices have been getting progressively smaller with each generation for years, and they’ve required progressively thin silicon wafers in their construction. At first glance, these ultra-thin wafers seem to have smooth reflective surfaces that require no polishing. However, the silicon grinding process used to make these wafers will always leave some subsurface damage. It may only be a few microns worth of damage, but that can be enough in today’s most advanced electronics.
In order for silicon wafers to be as flexible as they need to be, they must undergo a polishing process. Silicon wafer polishing will remove between five and ten microns of silicon, leaving behind a surface that is almost entirely free of the imperfections that are present on the unpolished wafers.
During the silicon wafer polishing process, a wafer is held in place by a vacuum carrier and slowly lowered into a polishing pad. The wafer is covered with a diamond liquid slurry that is designed for polishing very thin silicon wafers. The pad slowly, carefully yet thoroughly polished until impurities are removed.
In most cases, only one side of a silicon wafer is polished. This is the side that is integral to the circuitry of a smaller electronic device, and it needs to be nearly flawless if the device is to work properly. As devices continue to grow smaller, they’ve required two-sided silicon wafers. These wafers of course need to be polished on both sides, which will always present a challenge to any service performing silicon wafer manufacturing and polishing.
Whenever silicon is being used, there is always the chance that it could be damaged, which is why silicon wafer polishing is so important. These wafers need to be as close to perfect as possible, especially as our electronics have become smaller. The silicon wafer polishing process will always continue to evolve as thinner and more precise wafers are necessary. The current polishing process works very well, but there’s no telling what we will see in the future as the technique continues to evolve.