Ink jet printhead having ionic passivation of electrical circuitry
US5010355A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 26, 1989 |
| Grant date | Apr 23, 1991 |
| Priority date | — |
| Expiry date | Dec 26, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An improved ink jet printhead is disclosed of the type having a plurality of parallel ink flow channels which terminate with an ink droplet emitting nozzle, a heating element with a cavitational protective layer thereover located in each channel, and MOS electronic circuitry monolithically integrated within the printhead for applying electrical pulses to the heating elements. The pulsed heating elements produce bubbles momentarily on the protective layer of the heating elements which expel ink droplets from the nozzles. The improvement is obtained by providing multi-layer ionic passivation of the MOS electronic circuitry which is exposable to the ink. This is accomplished through the deposition of a multi-layered, thin film insulative coating thereon consisting of a first layer of doped or undoped silicon dioxide having a thickness of 200 .ANG. to 2 .mu.m followed by a second layer of plasma nitride having a thickness of 1000 .ANG. to 3 .mu.m. The silicon nitride is etched from the protective layers of the heating elements and electrical contact pads for external connection to electrical power so that the first layer of silicon oxide is exposed, followed by etching of the silicon o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.