Patent ID: 8129204

Claim:
A method of manufacturing a liquid discharge head substrate, the liquid discharge head substrate comprising: a substrate; a heating resistor layer formed on the substrate; a flow path for a liquid; a conductive layer stacked on the heating resistor layer and having an end portion which forms a step portion on the heating resistor layer; and a protective layer covering the heating resistor layer and the conductive layer including the step portion, and formed between the heating resistor layer and the flow path, the protective layer being provided by stacking a plurality of layers, the method comprising forming a first layer of the plurality of layers which is closest to the heating resistor layer by a plasma CVD method and a second layer of the plurality of layers which is furthest from the heating resistor layer by supplying at least a gas containing silicon and a gas containing nitrogen at a substrate temperature of 50° C. to 400° C. by a Cat-CVD method.