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 Si.sub.wO.sub.xC.sub.yN.sub.z (w+x+y+z=100 (at. %), 37≤w≤60 (at. %), 30≤x≤53 (at. %), 6≤y≤−29 (at. %), 4≤z≤9 (at. %)).

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): Si.sub.w1O.sub.x1C.sub.y1 (I), 39≤w1≤62 (at. %), 32≤x1≤55 (at. %), and 6≤y1≤29 (at. %), and w1+x1+y1=100 (at %).

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.

A fluid ejection device may include a fluid ejection die embedded in a moldable material, a number of fluid actuators within the fluid ejection die to recirculate fluid within a number of firing chambers of the fluid ejection die, and a number of cooling channels defined in the moldable material thermally coupled to the fluid ejection die.

A wafer structure is disclosed and includes a chip substrate and a plurality of inkjet chips. The chip substrate is a silicon substrate fabricated by a semiconductor process. At least one inkjet chip is directly formed on the chip substrate by the semiconductor process and diced into the at least one inkjet chip for inkjet printing. Each of the inkjet chip includes a plurality of ink-drop generators produced by a semiconductor process and formed on the chip substrate. Each of the ink-drop generators includes a thermal-barrier layer, a resistance heating layer, a conductive layer, a protective layer, a barrier layer, an ink-supply chamber and a nozzle.

A liquid ejection head includes an ejection-port formed member including liquid ejection ports, a substrate including liquid supply ports for supplying liquid to the ejection ports and a partition between the liquid supply ports, and a substrate supporting member. The liquid supply ports extend along the longitudinal direction of the substrate when viewed from a position facing the main surface of the substrate. The liquid supply ports are arrayed along the lateral direction of the substrate when viewed from the position facing the main surface. The partition includes a non-contact portion that is not in contact with the supporting member and a contact portion that is in contact with the supporting member. Of the liquid supply ports, adjacent liquid supply ports communicate with each other in the lateral direction through a gap between the non-contact portion and the supporting member, and liquid flows through the gap.

A wafer structure is disclosed and includes a chip substrate and at least one inkjet chip. The chip substrate is a silicon substrate which is fabricated by a semiconductor process on a wafer of at least 12 inches. The at least one inkjet chip is directly formed on the chip substrate by the semiconductor process, and the wafer is diced into the at least one inkjet chip, to be implemented for inkjet printing.

A wafer structure is disclosed and includes a chip substrate and a plurality of inkjet chips. The chip substrate is a silicon substrate which is fabricated by a semiconductor process on a wafer of at least 12 inches. The plurality of inkjet chips include at least one first inkjet chip and at least one second inkjet chip. The plurality of inkjet chips are directly formed on the chip substrate by the semiconductor process, respectively, and diced into the at least one first inkjet chip and the at least one second inkjet chip, to be implemented for inkjet printing. Each of the first inkjet chip and the second inkjet chip includes a plurality of ink-drop generators produced by the semiconductor process and formed on the chip substrate.

A wafer structure is disclosed and includes a chip substrate and a plurality of inkjet chips. The chip substrate is a silicon substrate which is fabricated by a semiconductor process. The plurality of inkjet chips include at least one first inkjet chip and at least one second inkjet chip. The plurality of inkjet chips are directly formed on the chip substrate by the semiconductor process, respectively, and diced into the at least one first inkjet chip and the at least one second inkjet chip, to be implemented for inkjet printing. Each of the first inkjet chip and the second inkjet chip includes a plurality of ink-drop generators produced by the semiconductor process and formed on the chip substrate. Each ink-drop generator includes a barrier layer, an ink-supply chamber and a nozzle. The ink-supply chamber and the nozzle are integrally formed in the barrier layer.

A wafer structure is disclosed and includes a chip substrate and a plurality of inkjet chips. The chip substrate is a silicon substrate which is fabricated by a semiconductor process on a wafer of at least 12 inches. The plurality of inkjet chips include at least one first inkjet chip and at least one second inkjet chip. The plurality of inkjet chips are directly formed on the chip substrate by the semiconductor process, respectively, and diced into the at least one first inkjet chip and the at least one second inkjet chip, to be implemented for inkjet printing.