Abstract: A substrate for liquid ejection head comprising, a base material, a heating element including a heating resistor layer for generating thermal energy for discharging a liquid, a wiring layer for supplying electric power to the heating element, and an interlayer insulating film for insulating the heating resistor layer and the wiring layer. A part of a first interlayer insulating film for insulating the heating resistor layer and a first wiring layer adjacent to the heating resistor layer, and a second interlayer insulating film for insulating the first wiring layer and a second wiring layer adjacent to the second interlayer insulating film, includes a material layer represented by SiwOxCyNz (w+x+y+z=100 (at. %), 37?w?60 (at. %), 30?x?53 (at. %), 6?y??29 (at. %), 4?z?9 (at. %)).

Abstract: Long-term reliability of a liquid ejection head substrate and a liquid ejection head is improved by suppressing dissolution of an intermediate layer due to anodization. A liquid ejection head substrate including: a flow passage forming member having an ejection orifice and a flow passage; a heating resistance element for ejecting a liquid; an insulating layer covering the heating resistance element; a protecting layer whose surface is exposed to the flow passage; and an intermediate layer provided between the flow passage forming member and the protecting layer, in which the intermediate layer contains a material represented by a following composition formula (I): Siw1Ox1Cy1 (I), 39?w1?62 (at. %), 32?x1?55 (at. %), and 6?y1?29 (at. %), and w1+x1+y1=100 (at %).

Abstract: A liquid ejection head circuit board including a substrate, a heat generating resistance element that generates heat energy used for ejection of liquid, an electric wiring layer that is electrically connected to the heat generating resistance element, and an insulating film that insulates the electric wiring layer. The insulating film includes a first insulating film and a second insulating film on the first insulating film, the first insulating film is a first SiOCN film, and the second insulating film is a second SiOCN film containing more carbon than the first SiOCN film or a low-density insulating film with a lower density than the first SiOCN film.

Abstract: A liquid ejection head circuit board including a substrate, a heat generating resistance element that generates heat energy used for ejection of liquid, an electric wiring layer that is electrically connected to the heat generating resistance element, and an insulating film that insulates the electric wiring layer. The insulating film includes a first insulating film and a second insulating film on the first insulating film, the first insulating film is a first SiOCN film, and the second insulating film is a second SiOCN film containing more carbon than the first SiOCN film or a low-density insulating film with a lower density than the first SiOCN film.

Abstract: Long-term reliability of a liquid ejection head substrate and a liquid ejection head is improved by suppressing dissolution of an intermediate layer due to anodization. A liquid ejection head substrate including: a flow passage forming member having an ejection orifice and a flow passage; a heating resistance element for ejecting a liquid; an insulating layer covering the heating resistance element; a protecting layer whose surface is exposed to the flow passage; and an intermediate layer provided between the flow passage forming member and the protecting layer, in which the intermediate layer contains a material represented by a following composition formula (I): Siw1Ox1Cy1 (I), 39?w1?62 (at. %), 32?x1?55 (at. %), and 6?y1?29 (at. %), and w1+x1+y1=100 (at %).

Abstract: A substrate for liquid ejection head comprising, a base material, a heating element including a heating resistor layer for generating thermal energy for discharging a liquid, a wiring layer for supplying electric power to the heating element, and an interlayer insulating film for insulating the heating resistor layer and the wiring layer. A part of a first interlayer insulating film for insulating the heating resistor layer and a first wiring layer adjacent to the heating resistor layer, and a second interlayer insulating film for insulating the first wiring layer and a second wiring layer adjacent to the second interlayer insulating film, includes a material layer represented by SiwOxCyNz (w+x+y+z=100 (at. %), 37?w?60 (at. %), 30?x?53 (at. %), 6?y??29 (at. %), 4?z?9 (at. %)).