High temperature graphite meander elements for wafer heating applications in PVD, CVD, PECVD and etch processes

Our graphite meander elements come in either CVD coated, or uncoated versions. The meander element is a very flexible way of heating a substrate or silicon wafer in a deposition system. The design of the meander is such that a long path length is cut from graphite sheet, usually to the shape of the wafer being processed. This allows very flexible control over the way heat is applied to the wafer. Path widths can be increased or decreased to provide hot or cold zones, or with a constant path length very high thermal uniformity and thermal coupling can be achieved.

Meander elements are usually circular or linear in the meander style. Circular elements are usually more flexible in their design as they can accommodate clear areas to allow for components or parts of the transfer stage to pass through.

As the base material is usually graphite they can, dependant on atmosphere, heat substrates to a temperature higher than 2000°C. Pure graphite elements are limited to 450°C in an oxygen atmosphere because they start to convert to carbon dioxide very rapidly above this temperature. Uncoated graphite elements also tend to generate sub micron particles of graphite when subject to vacuum/atmosphere pumping cycles, and because it is a porous material they tend to outgas when under vacuum. Because of this a drop in process yield can occur.

To combat the above drawbacks with uncoated graphite elements that are to be used above 450°C, we have developed chemical vapor deposition coatings that seal the graphite surface from reactive environments that would otherwise etch the material away. The CVD coatings also have the added benefit of stopping particle generation and out gassing from the material.

The following coatings are available for meander elements and components:

• Silicon carbide / Silicon carbide converted
• Boron nitride / Pyrolytic Boron nitride (™BoraVac Pbn)
• Aluminum Nitride
• Pyrolytic graphite (™PyroVac Pg)
• Vitreous graphite

For an explanation on the above coatings please go to our CVD/PVD coatings page.

If you have an application or an element that needs replacing please contact us by email, fax or telephone and we will be glad to help.

Boravac and Pyrovac are registered trademarks of CEVP Ltd U