Shutter disk having a tuned coefficient of thermal expansion

A process chamber, comprising:

• a chamber body defining an inner volume having a target comprising titanium (Ti) to be deposited atop a substrate disposed therein;
• a substrate support disposed within the chamber body for supporting the substrate;
• a shutter disk for protecting the substrate support, the shutter disk comprising a body having a top surface, a bottom surface and a peripheral surface coupling the top surface to the bottom surface, the bottom surface having an outer step adjacent the peripheral surface, an inner step adjacent the outer step, and an annular groove formed in the bottom surface, wherein the inner step is disposed radially inward of the outer step and the annular groove is disposed radially inward of the inner step, wherein a thickness of the body increases from the outer step to the inner step, wherein the body is formed from a composite material comprising aluminum and silicon provided in a ratio of aluminum to silicon of about 1:4 to about 7:3, and wherein the ratio of aluminum to silicon provides a coefficient of thermal expansion of the body that is substantially similar to a coefficient of thermal expansion of the titanium (Ti) to be deposited on the shutter disk;
• and
• a transfer robot movably coupled to the chamber body for transferring the shutter disk to the substrate support.