Heater stack and method for making heater stack with heater element decoupled from substrate

A method for making a heater stack for a micro-fluid ejection device, comprising:

• processing one sequence of materials to produce first strata supporting and forming a fluid heater element, wherein said processing the one sequence of materials includes
• depositing a sacrificial layer of a predetermined material on a substrate, and
• depositing and patterning layers of resistive ant conductive materials on the sacrificial layer to produce heater substrata supporting and forming thereon the fluid heater element responsive to repetitive electrical activation and deactivation to produce repetitive cycles of fluid ejection from said device, each cycle involving alternating periods of heat-up and cool-down of the fluid heater element corresponding respectively to the repetitive electrical activation and deactivation of the fluid heater element, and
• decomposing the sacrificial layer of the predetermined material so as to produce a coupled relationship between at least the fluid heater element and the substrate which, during the heat-up period of a respective one of said cycles of fluid ejection, results in the fluid heater element buckling away from and out of physical contact with the substrate due to thermal expansion of the fluid heater element in response to the electrical activation thereof enabling the fluid heater element to transfer heat energy for producing fluid ejection into the fluid substantially without transferring the heat energy into the substrate whereas the decoupled relationship, during the next following cool-down period of the respective one of the repetitive cycles of fluid ejection, results in the fluid heater element de-buckling back toward and into physical contact with the substrate due to thermal contraction of the fluid heater element in response to the electrical deactivation thereof enabling the fluid heater element to transfer residual heat energy to the substrate and prepare for the following heat-up period of the next respective one of the cycles of fluid ejection;
• and
• processing another sequence of materials to produce second strata overlying the heater substrata and the fluid heater element thereof to provide protection of the fluid heater element from adverse effects of the repetitive cycles of fluid ejection.

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 fluid ejection from said device;
• and
• second strata overlying said first strata to provide protection of said fluid heater element from adverse effects of said repetitive cycles of fluid ejection, each cycle involving alternating periods of heat-up and cool-down of said fluid heater element;
• wherein said first strata includes
• a substrate,
• a heater substrata overlying said substrate, and
• a sacrificial layer of material deposed between said substrate and said heater substrata and processed so as to provide a decoupled relationship at least between said fluid heater element and said substrate, such that said fluid heater element moves away from and out of physical contact with said substrate in response to the electrical activation thereof, and said fluid heater element moves back into physical contact with said substrate during a following cool-down period of the one of said cycles.