Here at Airbrasive, we love a challenge. And no challenge is too big—or too microscopic. So when a global leader in electronic components came to us and said they needed 100 micrometers shaved off their extremely delicate silicon wafers, we couldn’t wait to put our micro abrasive systems to the test. With over 65 years of experience, we were confident we could find a solution that worked.
We were tasked with reducing the thickness of silicon wafers. These are made from semiconductive material cut into a thin slice, and are used by the electronics industry to make microdevices like integrated circuits. The wafers we were given were too thick. It was our job to reduce their thickness by 300-400μm.
How big is a micrometer? It’s 1,000 times smaller than a millimeter—that’s one millionth of a meter! Add to that the fact that the thin wafers are very delicate, and we knew we had our work cut out for us.
We love stepping up to a challenge. To provide the necessary support to the delicate wafers, we started by gluing them to a larger glass disc. We spun the wafers continuously at a velocity of 120 revolutions per minute while the nozzle of our blasting device moved back and forth from the edge to the center. To control the motion, we deployed software, microprocessors, and stepper motors. Then we used a 50μm aluminium oxide powder blasted at a pressure of 100 pounds per square inch to remove material from the wafers, at a distance of just 2mm.
We had to ensure that all areas of the wafer experienced the same cumulative process time so that thickness would be uniform across the entire surface. We developed a software algorithm to make this happen. The nozzle of the micro abrasive blasting device made two cycles lasting a total of 45 minutes, and we repeated this process twice to achieve the required thickness.
After 90 minutes, the process was complete. Using the decrement in weight of the wafers, we were able to measure the change in thickness indirectly.
We had done it! The wafers had been reduced to the required thickness, while still meeting roughness requirements.
We’re never satisfied to rest on our laurels, and are currently conducting more tests to improve throughput and process capability, as well as redesigning a few components to make them better suited for rigorous applications like this. We can’t wait to share those results!
Got a challenge for us? Get in touch to find out if Airbrasive can solve it!