Plasma Cleaning in Electron Microscopes - How the Industry Has Changed

In this interview AZoM speaks to Ron Vane, founder of XEI Scientific, about the 20th anniversary of Evactron plasma cleaning in electron microscopes.

How did XEI Scientific begin?

I used to work for Hitachi Instruments doing SEM Service Support Engineering and was asked to find solutions for contamination problems. I found a way to remove contamination by purging with nitrogen gas. However I was laid off before selling a system.  I knew that there were a lot of potential customers interested in an anti-contamination system so I started selling my own system to them. I had to re-engineer the way the system worked to differentiate it from my Hitachi solution.

In 1997 I realized that my technology needed to be improved. I was aware of a paper published in 1995 citing that a researcher had installed plasma cleaning on an electron microscope. This research was conducted in a government laboratory and a patent license was available. I decided to build upon this technology and commercialize it, so that it could be used by SEM users.

How did you move forward from there?

I found a company that could provide me with the RF plasma technology I needed to develop the system. We made and sold the first Evactron^® RF plasma cleaning system in 1999 and continued to sell more. For the first three years, we were lucky to sell more than one system a month, but this was enough to keep the business going and to allow us to develop a good reputation with the microscope community.

In 2003 my partner RF technology company merged into a parent company, and they stopped working with third parties. Fortunately, the contract we were working under allowed me to purchase the production technology from them. I expanded XEI Scientific and we began our own manufacturing.

We opened our plant in 2003 and shipped the first Evactron unit that we had built ourselves in February 2004. We slowly increased our sales and improved our production processes to create a better system. At this point we introduced the 5-year warranty that we still have today. We were still learning how to build the system in the best way possible, and the last thing we wanted to do was sell a system to our customers that was going to fail.  As a result of this philosophy of constant improvement we have developed a reputation for quality.

How did the company develop from there?

We listened to our customer’s needs and feedback on our first models and continued to improve our technology. In response to this, we developed our first programmable units - our first microprocessor-controlled unit was released in 2008 and this continues to be a flagship product for us.

How has your technology improved over time?

In 2010 we started working on Evactron systems that operated at a lower pressure/higher vacuum than the systems we were using.  We wanted to operate at lower pressures because cleaning is more effective at lower pressures as the oxygen radical species last longer. We wanted to improve our system so that we could out-compete similar technologies that were offered by new competitors.

The good thing about competition is that it forces you to develop a better product. We released our first product for lower pressure cleaning, the Zephyr, in 2012. In the spring of 2013, we determined a way to simplify the system which helped us to reduce costs - this became the E-series. The E-series uses a fixed gas leak rate, rather than a servo-controlled flow rate based on gas pressure, to produce a plasma vacuum.

We introduced the E-series in 2015. At first, we had some unanticipated issues with the system striking plasma at high vacuum. To solve this, we changed to using a higher powered external hollow cathode source, which is a lot cleaner, on the Evactron E50. This source can operate at a higher power without overheating or sputter damage.

As always, we are continuing to develop our products even further. We have introduced another new model that addresses some specific technical customer needs in a niche market and can also be sold at a lower price point. Plasma cleaning technology is soon going to be wanted by almost everybody in the industry whether they use a tungsten or field emission electron microscope. As sales will be high it should be possible to push prices down - we want to do this so that more users can afford to have the benefits of clean imaging.

What does the future have in store for XEI Scientific?

I think that plasma cleaning has to be simplified. We now have another competitor, and they have a research background. This competitor wants to produce a machine with maximum flexibility, and release a machine that can measure plasma density and more - this could be used to optimize the plasma for cleaning. I think that this is a bad approach because users with electron microscopes simply want to clean them, they don't want to do plasma research.

We provide systems that can be used for cleaning by everybody, not designed to be a research race car. We produce the Volkswagen of plasma cleaners - a well-designed, reasonably priced, and accessible product. We have sold almost 3000 units in the last 20 years.

Where is XEI Scientific based?

We're in Redwood City California, which is halfway between San Francisco and San Jose, meaning we're in the heart of Silicon Valley. There used to be many more instrumentation companies in the area. We used to have Varian, Applied Biosystems, HP, and Finnigan as neighbors, though they have now been absorbed into bigger enterprises.

About Ron Vane

Ron founded XEI Scientific in 1991 to fight contamination problems in Electron Microscopes after working for Hitachi as a service support engineer. In 1997, he started to work on plasma cleaning to clean hydro-carbon contamination. In 1999 he invented and introduced the Evactron De-Contaminator to do remote plasma cleaning inside Electron Microscopes.

In 2003 he moved the manufacturing of the Evactron systems to his own facility. In 2008 XEI Scientific introduced microprocessor-controlled units. XEI Scientific invented a plasma cleaning system for TEM in 2011. In 2013 XEI Scientific finished development of the low-pressure Zephyr Evactron to do flowing afterglow cleaning. During the testing process he discovered and invented "Pop" plasma ignition. In 2015 XEI Scientific introduced the low-price E series Evactron units with "Pop" ignition and flowing afterglow that are able to start immediately from a high vacuum and run on turbomolecular pumped vacuum systems.