US Patent 7905569 Planarization layer for micro-fluid ejection head substrates

A substantially inorganic planarization layer for a micro-fluid ejection head substrate and method therefor. The planarization layer includes a plurality of layers composed of one or more dielectric compounds and at least one spin on glass (SOG) layer having a total thickness ranging from about 1 microns to about 15 microns deposited over a second metal layer of the micro-fluid ejection head substrate. A top most layer of the planarization layer is selected from one or more of the dielectric compounds and a hard mask material.