An element substrate of a liquid ejection head includes an ejection element for ejecting a liquid, a plurality of electrode pads for receiving power for causing the ejection element to eject the liquid, and a sensor for detecting that the liquid has invaded the vicinity of the plurality of electrode pads. The sensor has first wiring connected with one electrode pad of the plurality of electrode pads and second wiring connected with one electrode pad different from the electrode pad connected with the first wiring.

A process for handling MEMS wafers includes the steps of: (i) attaching a first carrier substrate to a first side of a MEMS wafer, the first carrier substrate being attached via a first wafer bonding tape and a silicone-free peel tape, the peel tape contacting the first side of the MEMS wafer; (ii) performing wafer processing steps on an opposite second side of the MEMS wafer; (iii) releasing the first carrier substrate from the first side of the MEMS wafer via exposure to an energy source, the energy source selectively releasing the wafer bonding tape from the first side of the MEMS wafer; and (iv) peeling the peel tape away from the first side of the MEMS wafer.

A liquid ejection head includes a recording element substrate including an ejection port member including a liquid ejection port, an electrical wiring layer including a pressure generating element that pressurizes the liquid to eject the liquid and an electrically connecting part connected to the pressure generating element to supply power for driving the pressure generating element to the pressure generating element, and a silicon substrate having the ejection port member and the electrical wiring layer. The silicon substrate includes a through-hole passing through the silicon substrate to expose the electrically connecting part. An outer shape of an opening of the through-hole on the back side of the silicon substrate has no side parallel to direction [110] of the silicon substrate or has a side parallel to the direction [110]. The side has a length equal to or less than half an entire length of the through-hole in the direction [110].

An ink jet recording head includes an ejection chip in which a plurality of ejection orifices performing ejection are arranged; an external wiring board including an external wiring for applying an electric signal to the ejection chip from an outside; an electrical bonding portion where the external wiring of the external wiring board and the ejection chip are electrically bonded to each other; and a resin sealing portion that seals the electrical bonding portion, in which a corner of the external wiring board where a first end surface on an ejection chip side and a side end surface connected to the first end surface intersect has a chamfered portion which is chamfered, and the chamfered portion is positioned within a width of the ejection chip in an ejection orifice arrangement direction.

A liquid ejection head includes a liquid ejection head substrate having ejection elements that generate liquid ejecting energy, an ejection port formation member having ejection ports, and liquid chambers between the liquid ejection head substrate and the ejection port formation member to house liquid to be ejected through the ejection ports. The liquid ejection head substrate includes a substrate, an insulating film stacked on the substrate to insulate the ejection elements, communication ports in the substrate and the insulating film to communicate with the liquid chambers, and a liquid-resistant insulating film adherent to the ejection port formation member. The liquid-resistant insulating film covers the insulating film at its ejection port formation member side and includes a first portion partially contacting the ejection port formation member and a second portion covering the inner surfaces of the communication ports in the insulating film, the first and second portions being continuous.

An inkjet printing head includes a piezoelectric element that includes a lower electrode disposed on a movable film, a piezoelectric film formed on the lower electrode, and an upper electrode formed on the piezoelectric film, a hydrogen barrier film that covers, in a front surface of the piezoelectric element, at least, entireties of side surfaces of the upper electrode, the piezoelectric film, and the lower electrode, at least a part of an upper surface of the upper electrode, and an upper surface of the lower electrode, a first interlayer insulating film formed on a front surface other than an end surface of the hydrogen barrier film, a second interlayer insulating film formed so as to cover the end surface of the hydrogen barrier film and the first interlayer insulating film, and a wiring that is formed on the second interlayer insulating film and that is connected to the piezoelectric element.

A piezoelectric body layer of a first area has (100) plane preferential orientation, and a (100) plane orientation ratio of the piezoelectric body layer of a second area is lower than a (100) plane orientation ratio of the piezoelectric body layer of the first area, when one area far from an end portion of a second electrode is the first area, and one area near the end portion of the second electrode is the second area, of two areas of the second electrode in a second direction intersecting a first direction.

An inkjet printing head 1 includes an actuator substrate 2 having pressure chambers (cavities) 7, a movable film formation layer 10 including movable films 10A disposed above the pressure chambers 7 and defining top surface portions of the pressure chambers 7, and piezoelectric elements 9 formed above the movable films 10A. Each piezoelectric element 9 includes a lower electrode 11 formed above a movable film 10A, a piezoelectric film 12 formed above the lower electrode 11, and an upper electrode 13 formed above the piezoelectric film 12. The piezoelectric film 12 includes an active portion 12A with an upper surface in contact with a lower surface of an upper electrode 13 and an inactive portion 12B led out in a direction along a front surface of the movable film formation layer 10 from an entire periphery of a side portion of the active portion 12A and having a thickness thinner than that of the active portion 12A.

A method of generating a microfluidic ejection chip is provided. The method includes creating an opening in a silicon substrate through multiple iterations of a deep reactive ion etching process, forming a passivation layer over any exposed portion of silicon at the opening following each iteration of the deep reactive ion etching of the silicon substrate, and not removing the passivation layer at a conclusion of the etching of the silicon substrate to define a fluid passageway at the opening in the silicon substrate, such that the passivation layer is permanent on the silicon substrate at the opening.

An electrode pad portion of a liquid ejection head substrate includes a layer containing one of an iridium metal and an iridium alloy, and at least a portion of a cavitation resistant layer is provided in the same layer with the same material as the layer containing one of the iridium metal and the iridium alloy.