by Chi-I Lang, VP of workflow products and applications, Intermolecular Inc.
June 29, 2011 – The American Vacuum Society’s 2011 Atomic Level Deposition Conference in Cambridge, MA, logged an excellent second day, with the focus shifting towards ALD manufacturability, and a number of sessions that could only be described as "cool."
For semiconductor veterans, the ALD Conference is reminiscent of SEMICON West shows in the 1970s and 1980s: lots of ambitious competitors pursing a new and expanding market — with actual hardware on display — and a sense that everyone at the show was witnessing the real-time development of new production technologies. It’s an exciting feeling, and suggests that ALD has a very bright future ahead in a wide range of applications, with its outstanding film quality, wide range of precursors, and excellent step coverage (one presenter showed coatings on carbon nanotubes with an amazing 2000:1 aspect ratio).
|Atomic Level Deposition Conference 2011|
|Day 1: Interface engineering, rabbit ears and Roy Gordon|
|Day 2: Manufacturability takes center stage|
|Day 3: Precursor needs, spatial ALD, and butterfly wings|
A number of presenters discussed alternative approaches to ALD processing, breaking away from the traditional wafer-in-chamber model in search of higher throughput, the ability to deposit on a wider range of substrates, and more process flexibility.
Dutch equipment developer Levitech NV, one of the few suppliers able to show video of its equipment up and running, impressed the audience with their stated throughput of 3600 wafers/hour performing aluminum oxide passivation layer deposition on a solar cell production line. The spatial ALD system utilizes a continuous flow approach with no pulsing. A belt carries six-inch substrates past precursor dispensing stations; the belt’s speed is the controlling factor for deposition, in a process somewhat analogous to how an ion implanter achieves dose control.
Eastman Kodak’s David Levy provided another intriguing take, presenting a unique open-air spatial ALD approach to ALD on plastic. More than one attendee had to ask why Kodak is interested in ALD — the company is making a serious push in flexible substrates, and believes that it can use ALD as a patterning step in production of zinc oxide thin film transistors on plastic. The roll-to-roll process offers extremely high throughput and low cost. One challenge is the need to maintain very tight spacing (on the order of 100