A decade of innovation

In March 1996 a new company was born when a famous German optics maker acquired the E-Beam Lithography business of Jenoptik, developing Leica Microsystems Lithography in Jena. For the next decade the specialist segment of Leica developed some of the world's leading e-beam lithography systems, contributing to the continued extension of the Moore's Law principals.

As part of the 10th birthday celebrations, Leica Microsystems Lithography GmbH announced a new name: Vistec Electron Beam GmbH, the result of the acquisition of Leica's semiconductor activities by Golden Gate Capital, an investment company based in San Francisco. The Jena facility remains a division of Vistec Group, which currently has around 500 employees across the world.

Terms of the sale were not disclosed but investors have decided that this will be a growth area for the semiconductor industry. With technology nodes becoming increasingly more expensive to bridge, mask writing, defect review and alternative lithography are more vital to the manufacturing process than ever before.

"We are excited about our acquisition of Leica Microsystems' Semiconductor Business," said David Dominik, Managing Director of Golden Gate Capital. "Leica' s Semiconductor Business is well positioned for growth as a market leader in mask metrology, optical defect review, and direct-write E-beam lithography."

A new name
Leica's semiconductor business is now known as Vistec Semiconductor Systems consisting of three internationally active divisions providing key production technology that is used by most semiconductor manufacturers and many research institutes around the world. The new company is being led by Papken Der Torossian, a veteran in the global lithography field. Der Torossian is best known as the chief at SVG Lithography in California before it was sold to ASML. He brings a wealth of knowledge and experience to the Vistec group. Der Torossian complimented the Leica group after taking over for the way the group had been set up into three different technology sections. He saw no need to change the structure and created three divisions in the Vistec group along similar lines.

The three divisions will be known as 
- Vistec Semiconductor Systems GmbH - previously Leica Microsystems Semiconductor GmbH, located in Wetzlar, Germany 
- Vistec Electron Beam GmbH – previously Leica Microsystems Lithography GmbH, located in Jena, Germany 
- Vistec Lithography Ltd. - previously Leica Microsystems Lithography Ltd., located in Cambridge, UK

The recent anniversary celebrations in Jena focused on Vistec Electron Beam in celebration of the company's achievements. The event was well attended by local officials but this is no surprise as Jena has a long history with optics and fine mechanics, let alone electron beam lithography. Electron beam lithography systems have been produced in Jena since the late 1960s, first as part of Carl Zeiss Jena, then, after the collapse of the GDR, as part of Jenoptik, and in 1996 as a business unit of Leica Microsystems up until 2005. The company has had an interesting journey as Leica and Carl Zeiss have long been rivals in the optical world making Jena a key global area in optical manufacturing. Despite the long history of competition the companies also have a long history of cooperations. Electron beam lithography will still be produced in Jena but no longer under either Jena icons. Jena's electron beam company will be an independent force operating under the new name of Vistec.

E-Beam comes of age
Electron beam was considered as an alternative to optical lithography for many years. However, wafer throughput with electron beam lithography is too slow for use in mainstream semiconductor wafer production at present. Currently electron beam lithography is regarded as complementary to optical lithography. This is a view shared by Der Torossian in a recent interview with EuroAsia semiconductor.

"E-beam lithography will only be used as the primary tool to create ASICs," stated Der Torossian. "There will continue to be a market for mask writing lithography but the growth area will be in next generation lithography."

Der Torossian sees electron beam lithography filling in the gaps for optical lithography. Devices will mainly be manufactured using optical lithography but the smaller features will require electron beam lithography.

"When you are only using e-beam for a finite number of smaller features throughput will no longer be an issue," enthused Der Torossian. Electron beam lithography refers to the lithographic process that uses a focused beam of electrons to form the circuit patterns needed for material deposition on (or removal from) the wafer, in contrast with optical lithography which uses light for the same purpose. Electron beam lithography offers higher patterning resolution than optical lithography because it doesn't suffer from limitation of wavelength.

Given the availability of technology that allows a small-diameter focused beam of electrons to be scanned over a surface, an electron beam system no longer needs masks to perform its task (unlike optical lithography, which uses photomasks to project the patterns). An electron beam system simply ‘draws' the pattern over the resist wafer using the electron beam as its drawing pen. The serial way in which electron beam lithography produces the resist pattern is the reason throughput is so much slower than optical parallel production. As an example, to pattern a single layer of semiconductor containing 60 devices (each device consists of many layers) it would take an electron beam system approximately two hours; compared with less than two minutes for an optical system. Vistec Electron Beam GmbH has become one of the leaders in electron beam direct writing. The company also developed the variable shaped beam technology, and is the worlds first manufacturer of a line of electron beam systems with full 300mm writing capabilities. Today, about 15 of these "stage systems" are in use at research and commercial sites around the world. "Our experience and know-how ensure our future success," explains Dr. Sebastian Toelg, General Manager of Vistec Electron Beam GmbH. "We were proud to be part of Leica Microsystems, and are now equally confident as Vistec Semiconductor Systems."

From research to reality
As part of a European MEDEA+ research project (financed by the German Federal Ministry for Education and Research) and cooperating with European semiconductor manufacturers, Vistec Electron Beam GmbH succeeded in developing a market-ready mask-free lithography solution. In addition to an optimized "single beam process", the company is participating in another European cooperative project to launch a highly innovative and completely new concept - a lithography process that uses parallel electron beams to structure masks or wafers.

"This tradition of innovation describes our strengths," says Dr. Toelg. "We succeed today against strong competitors, which are currently all located in Japan thanks to our consistent ability to innovate." This is why over 40% of our over 80 employees are in R&D: "Our highly motivated, experienced and qualified people are the basis for our success."

Innovation also means investing in the future, such as the most modern production technologies to assure quality - and constant improvement – of provided systems.

Vistec Electron Beam GmbH and Fraunhofer CNT recently reported the start-up of a Leica ebeam system at the recently opened Fraunhofer Centre for Nano-electronic Technology (CNT) in Dresden, Germany. Representing a two-digit million amount capital investment, this system will be used for selected processes used in the development of high-density storage devices and high performance transistors.

Currently one of the most innovative direct write electron-beam system in terms of throughput, accuracy and automation, the system is using a variable shape beam to enable high precision direct write patterning down to 45 nm feature size. The system meets all requirements for the 65 nm technology node for 300 mm wafer lithography. Karl-Heinz Kliem, Vistek Electron Beam project leader, considers the CNT launch "a further step in strengthening Leica's position in wafer lithography with electron beam lithography systems."

As leading edge mask makers ramp up mask production for the 65nm technology node, their investment in production and quality control equipment is already at peak level but the need for innovation ensures that companies like Vistec will continue establishment for many more decades as a leading light in lithographic field of electron beam.