With Moore’s Law coming to an end, engineers have been forced to find new ways to continue the trend of integrating more transistors onto a chip. One of the leading solutions has been creating 3D ICs: layers of physically stacked silicon wafers connected with silicon vias. In this way, chips can continue to increase transistor count without needing to necessarily scale down any further.
3D IC technology using TSVs. Image used courtesy of Ridgetop Group
However, as with all new technologies, there are still many problems that need to be addressed in 3D IC technology. From a development standpoint, 3D ICs still need new process equipment, methods of measurement, and testing procedures.
PillarHall’s 3D IC Approach
One company that has been developing new ways to reliably test 3D ICs is PillarHall.
The company says it focuses on developing easy, fast, and accurate ways to characterize thin-film processes. Specifically, they develop test chips that are often used in thin-film conformality measurements in atomic layer deposition and chemical vapor deposition processes.
A wafer of PillarHall test chips. Image used courtesy of PillarHall
Conformality of a thin-film process, or how evenly coated a chip is, can be exceptionally important but challenging to quantify. In contrast to traditional vertical test structures, which rely on cross-sectional SEM/TEM analyses, PillarHall says it has pioneered a new lateral approach. This approach, it claims, enables the use of conventional surface analysis tools, meaning much faster and more accurate analyses.
PillarHall Teams Up With Chipmetrics
Now, in a strategic move, PillarHall has teamed up with Chipmetrics, a fellow Finnish company, to help commercialize its solution.
Initially, the duo will concentrate its market efforts on atomic layer deposition (ALD), since this is where the research has shown the test chip is most effective. Beyond this, the teams have already piloted the test chip on the international market.
Structure post-ALD coating and after peeling off the membrane. Image used courtesy of PillarHall
On this, Dr. Mikko Utriainen, founder of Chipmetrics says Chipmetrics is “familiar with the challenges of a research-oriented start-up for an academic entrepreneur. PillarHall’s journey has so far been exceptionally successful in many ways. Its unique business model and product, market, demand, customer feedback, sales channels, and scalability are all very promising.”
3D ICs is a “beyond-Moore” technology, one which is expected to continue innovation in the semiconductor industry. As with all new technologies, there are still holes to be filled with respect to methods of testing and analysis, and that’s exactly what these Finnish companies are looking to address.
More on 3D ICs and Vertical Integration
3D IC technology is not new by any means. In recent years, we’ve seen some impressive leaps and bounds, however. Check out some recent discussions on vertical integration.