Guides / Applications

What Fab Equipment Buyers Actually Specify on a Ceramic Part

August 17, 2026

Semiconductor equipment is one of the largest users of machined technical ceramics, and it is also the most demanding place to be a supplier. The reason is simple: a ceramic part inside a process chamber is not just a component, it is a potential source of contamination sitting above a wafer worth more than the part.

What the parts are

• Wafer handling blades and end effectors. Thin, stiff, low mass and low particle. Alumina, silicon carbide, aluminium nitride and silicon nitride all appear here
• Electrostatic chuck and heater bodies. Usually aluminium nitride or high purity alumina with embedded electrodes, demanding flatness and thermal uniformity
• Chamber insulators, rings and liners. High purity alumina, sometimes coated
• Gas distribution parts and showerheads. Many small holes, tight positional tolerance, high purity
• Lift pins, spacers, bushings and standoffs. Simple parts with demanding cleanliness

The four requirements that are different

1. Purity and phase. The number on the drawing is not a formality. At 96 percent alumina, roughly 4 percent glassy phase sits at the grain boundaries and it is attacked first by fluorine and chlorine chemistries. At 99.5 percent and above that phase is largely gone. See which alumina purity do you actually need.

2. Particle generation. Erosion is a contamination problem before it is a wear problem. Density, grain size and surface finish all feed into how many particles a surface sheds. A polished high density surface sheds far fewer than a coarsely ground one.

3. Flatness and thermal contact. Chuck and heater parts control wafer temperature through physical contact. Flatness and parallelism callouts here are functional, and they usually mean lapping. See lapping, polishing and flatness.

4. Cleanliness and traceability. The part has to arrive clean and stay clean. That usually means ultrasonic cleaning in DI water, a controlled dry, handling in a clean area, double bagging and a certificate that names the lot.

Metal contamination limits

Many fabs specify limits on sodium, iron, copper, calcium and other elements, measured in parts per million on the surface or in the bulk. That has consequences up the chain:

• The blank supplier and lot matter, not just the grade name
• Grinding wheels, coolant and handling can introduce contamination
• Cleaning chemistry and rinse water quality become part of the process specification

If your drawing has contamination limits, say so at the RFQ stage. It changes which shops can quote at all.

What to put on a semiconductor RFQ

1. Grade with minimum purity, density and maximum grain size
2. Plasma or chemistry exposure, including the gases if you can share them
3. Flatness, parallelism and finish on the faces that contact or seal
4. Any coating requirement, and whether the shop applies it or a partner does
5. Cleaning, packing and labelling requirements
6. Contamination limits and the test method
7. Whether first article inspection and lot traceability are required

A note on lead time

These parts often need a high purity blank that is not a common stock item, which pushes lead time out. If you have a tool build date, put it on the RFQ. A shop that knows the date can propose a grade or a size that is actually on a shelf, and that conversation saves more time than any amount of expediting later. The background is in what drives ceramic machining costs.

See also: ceramic parts for semiconductor equipment by chamber position.

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Frequently asked questions

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