At the Crossroads of CVD and ALD, KOBUS Makes its Mark on 3D TSVs
Last July at SEMICON West, I was honored to witness the dramatic unveiling of UnitySC, the new company formed as a result of Fogale Group’s acquisition of Altatech, resulting in a semiconductor equipment portfolio that spans the spectrum of process control needs for advanced wafer-level and 3D packaging, including metrology, edge inspection, and defect detection. But that was only part of the story.
A few weeks ago at SEMICON Europa, a second equipment company was launched out of this same Fogale Group acquisition to leverage Altatech’s chemical vapor deposition (CVD) and atomic layer deposition (ALD) know-how. The new company, KOBUS, has a unique offering called Fast Atomic Sequential Technology (F.A.S.T.), which reportedly produces step coverage as conformal as ALD with the speed of CVD for isolation, seed and barrier layers targeting high aspect ratio (HAR) through silicon via (TSV) structures.
I got a heads-up on this back in September during the European MEMS Summit, when I spoke with Patrice Nal, process support engineer at Altatech (and now the newly christened KOBUS) who explained the technology offering to me.
Currently, oxide isolation, barrier and seed layer processes for HAR TSVs are performed using plasma-enhanced CVD (PECVD) or PVD, which ends up with more material deposited on the top to get step coverage on the sides and bottom, subsequently requiring costly chemical mechanical planarization (CMP) processes. Nal explained that KOBUS’ FAST technique injects precursors and reactants to activate plasma in sequence using a modified CVD vacuum chamber. The result is conformal silicon oxide, titanium nitride, and Cu deposition generally only achieved through costly and slow ALD processes. Cost savings comes from CVD speed and drastic reduction of CMP process time.
Nal said that the process is already being used in LED manufacturing to deposit the transparent conductive oxide (TCO) top layer for 3D LEDs, and will be available soon for 3D TSV processes. The proprietary equipment and processes are built in a clean room facility shared with sister company, UnitySC.
So what is the significance behind the name, KOBUS? CEO, Julien Vitiello was happy to explain. “Our processes are FAST, our team is agile and our solutions are powerful. The best animal that describes this is a KOBUS, a kind of antelope,” he said. The KOBUS logo design incorporates a semiconductor circuit design in the shape of an animal, to represent the company’s past as Altatech and future as KOBUS. He added that the tagline, “process like no one” refers to the uniqueness of the FAST solution, which lies at the crossroads of CVD and ALD, where “thick and conformal matters.” Lastly, Vitiello explained that KOBUS customers benefit from four dimensions: X and Y for film uniformity, Z for conformality, T (time) thanks to the pulsing sequence capability. This is how KOBUS achieves ALD film performance at CVD speed. ~ FvT