Patent ID: 8079672

Claim:
A heater stack for a micro-fluid ejection device, comprising: first strata configured to support and form a fluid heater element responsive to repetitive electrical activation and deactivation to produce repetitive cycles of ejection of a fluid from an ejection chamber above said fluid heater element; and second strata overlying said first strata and contiguous with said ejection chamber to provide protection of said fluid heater element; wherein said first strata includes a substrate having a front surface and a rear surface with a cavity extending into the substrate for a given depth from the front surface toward the rear surface, a heater substrata overlying said cavity and substrate, and a residual decomposed layer of sacrificial material in the cavity resulting from processing out of the cavity a sacrificial material thereby leaving said cavity substantially empty of said sacrificial material such that during repetitive electrical activation said cavity enables said fluid heater element to transfer heat energy into the fluid in said ejection chamber for producing ejection of the fluid therefrom substantially without transferring heat energy into said substrate.