Inversely processed resistance heater
AssigneeHewlett-Packard Company
InventorWilliam J. Lloyd
Life of this patent
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Abstract
A unique inverse processed film resistance heater structure including a conventional passivation wear layer which is deposited directly on a first substrate. This deposition step is then followed by the deposition and patterning of resistance and conductive layers, and these layers are covered by an isolation layer and a thick support layer. The thick support layer is then bonded to a second substrate and the first substrate is removed so that a uniform, flat passivation layer is exposed. The result is a film resistor which has a reduced failure rate as compared to the prior art because it is covered by a planar passivation wear layer with fewer pin-holes and reduced stress.
Claims8
A resistance heater comprising:
- an electrically non-conductive, uniformly thick planar passivation wear layer having flat opposing major surfaces;
- a film resistor connected to a plurality of conductors permanently covered by the uniformly thick passivation wear layer, said uniformly thick passivation wear layer protecting the film resistor from externally applied stress;
- and
- a support layer underlying and supporting said film resistor and plurality of conductors.
Dependencies are inferred from the claim text.