Extremely Pure Pyroid® Pyrolytic Graphite for Ion Implantation
Global semiconductor manufacturers use ion implantation in most of their chip production processes. Ion implantation uses two or three closely spaced multiple-aperture electrodes to extract ions from a source and eject them in a collimated beam. The electrodes are called "grids" because they are perforated with a large number of small holes in a regular array under close tolerance.
Ion impact erosion of the ion optics (i.e., the grids) is the primary mechanism limiting the life of the ion grids. The erosion of the grid eventually weakens it to the point that the grid fails and breaks causing unnecessary and costly production down time.
Pyrolytic Graphite exhibits the lowest erosion rate of any known material, even in extreme working conditions such as in ion bombardment or in plasma applications.
Common grid material parts such as molybdenum and other fine-grain,high-desity graphite used in ion implantation equipment have very high erosion wear rates. Pyrolytic graphite has extremely low erosion rates due to its high purity > 99.999% and single crystal structure.
Customers using pyrolytic graphite grids for ion implantation enjoy a reduced cost of ownership due to the low erosion rates of the material. This is important since it improves productivity by enabling the user to operate longer without tooling changes and the associated costs of downtime during the tooling change over.
Since the ion grid focuses ions, minimizing erosion provides longer life and more precise beam focus, increasing productivity, lowering maintenance and saving costs from production down time.
With over 30 years of experience in the semiconductor industry, we produce components that conform precisely to the OEM specifications.
Electrodes Made From Pyrolytic Graphite have Zero porosity
Zero porosity translates into no outgassing of contaminants and no structure capable of trapping contaminants that can alter the dopant effect on the implantation.
The theoretical density of monocrystalline graphite is 2.26 g/cm3. The density of highly pure pyrolytic graphite is 2.23 g/cm3 which is greater than any known graphite due to its single crystal structure. This means that there is no porosity due to ash contamination in the material that degrades the structure. This porosity is found in even purified isostatically pressed, fine-grained graphite material.
In addition pyrolytic graphite offers:
- High purity > 99.999%
- Stability at high temperature and vacuums
- Extreme resistance to thermal shock
- Temperature tolerance from cryogenic to > 2000° C
Pyrolytic graphite has a stable coefficient of thermal expansion which means
temperature gradient effects on the ion grids are negligible.
Near zero thermal expansion means the grids maintain their relative spacing across of range of temperature and energy settings. This translates into more precise control for depositing dopant atoms into the substrate.
High Purity Pyrolytic Graphite
Pyrolytic Graphite can be easily machined and the material can be routinely manufactured into complicated parts with close tolerances. Pyrolytic Graphite is can be supplied with a high level of surface finish, flatness or a defined surface roughness.
- Ion Implantation Grids
- Wafer Trays
- Electrodes for Plasma Etch
- Brazing and glass-to-metal sealing jigs