The recent ICPT Technical Conference which was held at the Wildhorse Pass Resort in Chandler, Arizona, was the perfect setting for this technology-leading organization to honor Dr. Klaus Beyer, a retired IBM Fellow, with the “Lifetime Achievement Award” for outstanding contribution to the science and technology of the Chemical Mechanical Planarization process. Dr. Beyer is renowned to have made the first discovery of planarization.
In January of 1983, Dr. Beyer, an employee of IBM, was assigned the task of finding a way to eliminate silicon wafer surface scratching caused primarily by the traditional brush cleaning method used to remove the colloidal silica polishing slurry. As he diligently tried to resolve this issue, he was also assigned to work on trench glass isolation processing.
In his literature search, Dr. Beyer learned about a patent issued to the RCA Corporation about megasonic cleaning of silicon surfaces. He found out that a license for what became known as the “RCA clean” method had been sold to Fluorocarbon and that they were manufacturing a cleaning tool based upon that patent. A year and a half later IBM finally had that machine ordered and installed for Beyer to use. Beyer determined that it actually did clean the colloidal slurry from the polished surface but his manager wanted more evidence, so Beyer ran more qualification tests to gather more data. This meant that he had to polish more wafers so that he could clean them with this new technique. During this time, IBM was moving from 2 micron trench width to 1.5 micron. The glass trench reflow process worked well at 2 microns but did not fill properly at 1.5 microns and left unwanted mounds at random locations.
Dr. Beyer decided, as he says, to “spontaneously” try removing these unwanted and random mounds using a polishing technique he had learned during his wafer cleaning experiments. Because of time constraints on the production polishers, Dr. Beyer decided to polish the trench isolation test wafer with the reflowed glass fill that had the unwanted mounds on it, along with polishing a batch of prime silicon wafers that he needed for additional data generation and verification. He decided that after polishing all of these wafers he would run them through the megasonic cleaning system. After the polishing cycles were complete, he noticed that the isolation test wafer had an amazingly uniform green color, indicating that the remaining oxide was remarkably uniform. He examined all of these wafers and found that there were no scratches on the surfaces. The isolation test wafer surface was just as planar and just as scratch free as the polished bare silicon wafers! The random and unwanted glass mounds on the isolation test wafer were gone! The surface had been planarized!
Beyer knew he had made a tremendous discovery, but was concerned about how was he going to convince his management that rubbing the pristine surface of a device wafer against a textured polishing pad using abrasive colloidal slurry was such a good idea. Beyer presented his ideas and his data-driven findings to upper management and was able to secure support for a small team to pursue further research in Chemical Mechanical Polishing for the planarization of oxide thin film trench isolation. This process quickly proved viable for bipolar device processing and one year later his CMP process was adopted for manufacturing.
CMP is now used by nearly all fabs and foundries across the globe in the manufacture of semiconductors, MEMS, LED, TSV, III-V semiconductors, and other applications. Many devices now require more than two dozen CMP steps as part of the manufacturing process flow, enabling the fabrication of devices that are smaller, faster, and more powerful, and for use in literally every imaginable type of device. From the more than 6.5 billion cell phones in the world and 5 billion other “things” connected to the internet – CMP has been a key enabler in the accelerating growth of communication, computing, and overall productivity.
In the years since Dr. Byers’s first CMP experiment, planarization technology has become a significant and critical manufacturing process for semiconductor and related technologies. The leadership team of the International Conference of Planarization Technology created the “Lifetime Achievement Award” as a means to recognize individuals and groups that have had a critical and lasting role in advancing CMP technology. The ICPT Lifetime Achievement Award for Dr. Beyer recognizes his role as “the man who started it all,” for inventing and developing CMP as an effective process and manufacturing technology.
It was an honor to have Dr. and Mrs. Beyer in attendance at the conference and to have Dr. Beyer accept his award in person. As a keynote speaker on the final day of the meeting, Dr. Beyer shared the story of his discovery along with the description of the technical and organizational challenges he managed. The path from secretive first experiments through the initial implementation of a novel production process required careful thought and negotiation. Dr. Beyer’s presentation about the first CMP implementation is an uncommon story of serendipity, discovery, and determination, and it is a story that was very entertaining as well.
A special thank you is due to Bob Roberts, the Business Development Manager for Axus Technology, for his diligent research and for nominating Dr. Beyer for this first, and very deserved, ICPT Lifetime Achievement Award.