Abstract: A silicon direct bonding (SDB) method by which void formation caused by gases is suppressed. The SDB method includes: preparing two silicon substrates having corresponding bonding surfaces; forming trenches having a predetermined depth in at least one bonding surface of the two silicon substrates; forming gas discharge outlets connected to the trenches on at least one of the two silicon substrates to vertically penetrate the bonding surface; cleaning the two silicon substrates; closely contacting the two silicon substrates to each other; and thermally treating the two substrates to bond them to each other. The trenches are formed along at least a part of a plurality of dicing lines, and both ends of the trenches are clogged. Gases generated during a thermal treatment process can be smoothly and easily discharged through the trenches and the gas discharge outlet such that a void is prevented from being formed in the junctions of the two silicon substrates due to the gases.

Abstract: A piezoelectric inkjet head and a method of manufacturing the piezoelectric inkjet head. The piezoelectric inkjet head includes three single crystal silicon substrates bonded to each other. An upper substrate includes an ink inlet, a plurality of pressure chambers, and a plurality of piezoelectric actuators, a middle substrate includes a manifold, a plurality of restrictors, and a plurality of first dampers, and a lower substrate includes a plurality of nozzles. The middle substrate also includes a membrane that is formed under the manifold to mitigate a rapid pressure change in the manifold and if formed of a material different from the material used for forming the middle substrate. A cavity located under the membrane and at least one venting channel that connects the cavity to the outside are formed in the middle substrate or the lower substrate.

Abstract: A nozzle plate of an inkjet printhead, and a method of manufacturing the nozzle plate. The nozzle plate includes a substrate through which nozzles are formed; an ink-philic coating layer formed on an outer surface of the substrate and inner walls of the nozzles; and an ink-phobic coating layer selectively formed on the ink-philic coating layer disposed around the nozzles.

Abstract: A piezoelectric inkjet printhead including an upper substrate formed of a single crystal silicon substrate or an SOI substrate and having an ink inlet therethrough, and a lower substrate formed of an SOI substrate having a sequentially stacked structure with a first silicon layer, an intervening oxide layer, and a second silicon layer in which a manifold, pressure chambers, and dampers are formed in the second silicon layer by wet or dry etching, and nozzles are formed through the intervening oxide layer and the first silicon layer by dry etching, and a method of manufacturing the same.

Abstract: A silicon direct bonding (SDB) method by which void formation caused by gases is suppressed. The SDB method includes: preparing two silicon substrates having corresponding bonding surfaces; forming trenches having a predetermined depth in at least one bonding surface of the two silicon substrates; forming gas discharge outlets connected to the trenches on at least one of the two silicon substrates to vertically penetrate the bonding surface; cleaning the two silicon substrates; closely contacting the two silicon substrates to each other; and thermally treating the two substrates to bond them to each other. The trenches are formed along at least a part of a plurality of dicing lines, and both ends of the trenches are clogged. Gases generated during a thermal treatment process can be smoothly and easily discharged through the trenches and the gas discharge outlet such that a void is prevented from being formed in the junctions of the two silicon substrates due to the gases.

Abstract: A method of forming a hydrophobic coating layer on a surface of a nozzle plate of an inkjet printhead includes forming a plurality of nozzles in the nozzle plate, each of the nozzles having an exit, stacking a film on the surface of the nozzle plate to cover the exit of each of the nozzles, forming a predetermined metal layer on an inner wall of each of the nozzles and an inner surface of the film covering the exit of each of the nozzles using a plating method, removing the film from the surface of the nozzle plate, forming a hydrophobic coating layer on the surface of the nozzle plate to cover the metal layer exposed through the exit of each of the nozzles, and removing the metal layer formed on the inner wall of each of the nozzles and the hydrophobic coating layer formed on the surface of the metal layer.

Abstract: A piezoelectric inkjet printhead including an upper substrate, having an ink inlet, a manifold connected with the ink inlet, and a plurality of pressure chambers arranged along at least one side of the manifold, wherein the ink inlet passes through the upper substrate, and the manifold and the pressure chambers are formed in a lower surface of the upper substrate, a lower substrate disposed directly adjacent the upper substrate, the lower substrate having a plurality of restrictors each connecting the manifold with one end of each of the pressure chambers, and a plurality of nozzles each being formed in a position of the lower substrate that corresponds to the other end of each of the pressure chambers to vertically pass through the lower substrate, wherein the plurality of restrictors are formed in an upper surface of the lower substrate, and a plurality of piezoelectric actuators.

Abstract: A piezoelectric inkjet printhead capable of reducing a crosstalk and a method of manufacturing the same are provided. The inkjet printhead includes an upper substrate, an intermediate substrate, and a lower substrate that are sequentially stacked, wherein the upper substrate includes piezoelectric actuators on an upper surface of the upper substrate and pressure chambers and first restrictors on a lower surface of the upper substrate, the first restrictors extending from the pressure chambers and having a width smaller than a width of the pressure chambers, the intermediate substrate includes dampers passing therethrough, the dampers corresponding to the pressure chambers and second restrictors extending between the first restrictors and a manifold formed from a lower surface of the intermediate substrate and the lower substrate includes nozzles passing therethrough, the nozzles corresponding to the dampers.

Abstract: In a piezoelectric actuator for an ink-jet printhead, and a method of forming the same, formed on a flow path plate having a pressurizing chamber, the piezoelectric actuator for applying a driving force for ink ejection to the pressurizing chamber, the piezoelectric actuator includes a lower electrode formed on the flow path plate, a bonding pad formed on the flow path plate to be insulated from the lower electrode, wherein a driving circuit for voltage application is bonded to an upper surface of the bonding pad, a piezoelectric layer formed on the lower electrode at a position corresponding to the pressurizing chamber, wherein an end of the piezoelectric layer extends onto the bonding pad, and an upper electrode formed on the piezoelectric layer, wherein an end of the upper electrode extends beyond the end of the piezoelectric layer and contacts the upper surface of the bonding pad.

Abstract: A flat evaporator is provided. In the evaporator, a common chamber formed on a substrate with a predetermined diameter and depth for containing a coolant is divided into a vaporization cavity region, a capillary region surrounding the vaporization cavity region, and a manifold region surrounding the capillary region. The capillary region has a capillarity generator capable of generating capillary action, and a top plate is configured to include an exhaust unit including a gas collector to exhaust a gas coolant generated in the vaporization cavity region. The evaporator can be implemented as a small and thin cooling device for performing cooling without external power. Furthermore, the evaporator can effectively prevent degradation of fluid flow force due to coexistence of gas and liquid by isolating a liquid coolant from a vaporized coolant by a capillary region, thereby significantly improving heat exchange characteristics.

Abstract: A flat evaporator is provided. In the evaporator, a common chamber formed on a substrate with a predetermined diameter and depth for containing a coolant is divided into a vaporization cavity region, a capillary region surrounding the vaporization cavity region, and a manifold region surrounding the capillary region. The capillary region has a capillarity generator capable of generating capillary action, and a top plate is configured to include an exhaust unit including a gas collector to exhaust a gas coolant generated in the vaporization cavity region. The evaporator can be implemented as a small and thin cooling device for performing cooling without external power. Furthermore, the evaporator can effectively prevent degradation of fluid flow force due to coexistence of gas and liquid by isolating a liquid coolant from a vaporized coolant by a capillary region, thereby significantly improving heat exchange characteristics.

Abstract: A 3-dimensional comb structure using an electrical force, and an inertial detection sensor and an actuator both using the 3-dimensional comb structure are provided. In the 3-dimensional comb structure, a suspension structure, which is an inertia body, is separated a predetermined height from a substrate, maintaining the predetermined height from the substrate. A movable comb, which has at least one movable comb finger, protrudes perpendicularly from the suspension structure. A fixed comb, which has at least one fixed comb finger, protrudes perpendicularly from the substrate, in mesh with the movable comb. The 3-dimensional comb structure is driven by a voltage provided from a power supply unit which is connected to the movable comb and the fixed comb.

Abstract: A multilayered wafer with a thick sacrificial layer, which is obtained by forming a sacrificial layer of oxidized porous silicon or porous silicon and growing an epitaxial polysilicon layer on the sacrificial layer, and a fabrication method thereof are provided. The multilayered wafer with a thick sacrificial layer adopts a porous silicon layer or an oxidized porous silicon layer as a sacrificial layer such that a sufficient gap can be obtained between a substrate and a suspension structure upon the manufacture of the suspension structure of a semiconductor actuator or a semiconductor inertia sensor. Also, in a fabrication method of the wafer according to the present invention, a p+-type or n+-type wafer doped at a high concentration is prepared for, and then a thick porous silicon layer can be obtained simply by anodic-bonding the surface of the wafer. Also, when polysilicon is grown on a porous silicon layer by an epitaxial process, it is grown faster than when single crystal silicon is grown.