Electron Beam Lithography


The Electron Beam Lithography tool is located in room 045 of the ASTeCC building. Raith e-LiNE is an electron beam lithography tool with a 100 mm by 100 mm travel range.  It uses thermal field emission filament technology and a laser-interferometer controlled stage.  The column voltage varies from 100 eV to 30 keV and the laser stage moves with a precision of 2 nm.  There are six apertures on the system: 7.5, 10, 20, 30, 60, and 120 mm.  The electron beam current is controlled by selecting the appropriate aperture.  The system is equipped with a load lock, an automatic height sensing, and a fixed beam moving stage (FBMS).  Typically, large area patterns are divided into small writing fields that are stitched together.  The writing fields can vary from 500 nm to 2 mm.  The individual fields are written one by one by scanning the beam within the field.  In the FBMS mode, the beam position is fixed and the stage moves.  This allows writing of long features without stitching.

Design for the tool can be done on any Windows based computer. Copies of the software can be obtained from Brian Wajdyk.


More Info

The Raith e-LiNE system is an Electron-Beam Lithography tool (EBL) located in room 045 of the ASTeCC building. Electron-beam lithography is a specialized technique for creating layered samples such as integrated circuits at the nano scale. EBL “writes” using an electron beam, in the same way a scanning electron microscope (SEM) would “read”. By being exposed to the electron beam, those areas are removed to develop a mask to block or allow further processing like etching or placing down a layer in the exposed areas. The electron beam (e-beam) scans back and forth writing electrons, in the desired circuit pattern on a photo resist material sensitive to electrons. This is similar the process printers use when scanning back and forth while depositing droplets of individual ink. The photo resist material is now considered exposed and washed away

Specifically Raith’s e_LiNE system supports the following crucial nano-engineering tasks:

  • Nano-scale fabrication by electron beam lithography
  • Accurate navigation and easy relocation by laser-interferometer stage
  • Ultra-high resolution, electron-beam imaging
  • Precise, electron-beam metrology to measure critical dimensions

The EBL system is built by using a high quality SEM consisting of a: 1. An electron gun or source that supplies the electrons. 2. An electron column that directs and focuses the electron beam. 3. A mechanical stage that positions the sample under the electron beam. 4. A computer system that controls the placement of both the beam and stage at the nano level.

In addition to the SEM, there are also several further pieces of equipment: 1. A meter capable of reading a trillionth of the amount of electrons used in a small laptop computer. 2. A laser used to precisely measure where the sample is relative to the electron source

Electron Beam lithography has an incredibly high resolution, relative to other techniques. It can work with a variety of materials in many different patterns. These advantages allow electron beam lithography to have three niche markets:

Research: Because electron beam lithography writes at the nano-level, researchers can use it to make nano-scale structures which will in turn be used for such things as the study of quantum effects or other physics phenomena.

Mask making: Electron beam lithography allows the making of masks (stencils used in traditional optical lithography) relatively quick and easy

Prototypes: Electron beam lithography aids in the production of small volume specialty products and prototyping integrated circuits. Since electron beam lithography is flexible and provides such a high resolution, it allows for very quick, experimental designs

Design for the tool can be done on any Windows based computer. Copies of the software can be obtained from Brian Wajdyk.