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.

A wafer structure is disclosed and includes a chip substrate and at least one inkjet chip. The chip substrate is a silicon substrate fabricated by a semiconductor process on a wafer of at least 12 inches. The inkjet chip is directly formed on the chip substrate by the semiconductor process, whereby the wafer is diced, and the inkjet chip is produced, to be implemented for inkjet printing. The inkjet chip includes plural ink-drop generators produced by the semiconductor process and formed on the chip substrate. The ink-drop generators are arranged in a longitudinal direction to form plural longitudinal axis array groups having a pitch maintained between two adjacent ink-drop generators in the longitudinal direction, and arranged in a horizontal direction to form plural horizontal axis array groups having a central stepped pitch equal to or less than 1/600 inches maintained between two adjacent ink-drop generators in the horizontal direction.

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

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.

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.

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 microfluidic die may include a microfluidic passage and a protective layer provided adjacent to internal surfaces of the microfluidic passage. The protective layer may include a protective nano-crystalline material and a protective amorphous matrix encapsulating the protective nano-crystalline material.

A droplet discharge head includes: a nozzle configured to discharge a liquid as droplets; a pressure chamber defining substrate defining a pressure chamber communicating with the nozzle; a piezoelectric element including a first electrode, a second electrode, and a piezoelectric layer containing a perovskite-type composite oxide containing potassium (K), sodium (Na), and niobium (Nb) as a main component; and a vibration plate forming a part of a wall surface of the pressure chamber and configured to vibrate by driving of the piezoelectric element. A driving frequency f [Hz] of the piezoelectric element, a piezoelectric constant d.sub.31 [m/v] of the piezoelectric element, a ratio x of a Na molar fraction to a total value of a K molar fraction and the Na molar fraction in the piezoelectric layer, and a viscosity μ [Pa.Math.s] of the liquid at 25° C. satisfy a relationship represented by a formula (1).

A method for manufacturing a liquid ejection head including a substrate that includes a liquid supply port on a first surface, a liquid ejection port on a second surface, and a flow path that connects the supply port and the ejection port to each other such that the supply port and the ejection port do not communicate with each other in a direction intersecting with the first surface and the second surface, comprises: a liquid repellent film forming step of forming a liquid repellent film on the substrate; a masking step of covering a surface of the liquid repellent film on the second surface; and a plasma treatment step of generating plasma from the first surface toward the second surface to remove the liquid repellent film, wherein a portion of the liquid repellent film which remains inside the ejection port after the plasma treatment step is hydrophilized.