Abstract: It is an object to reduce defective conduction in a wiring board or a semiconductor device whose integration degree is increased. It is another object to manufacture a highly reliable wiring board or semiconductor device with high yield. In a wiring board or a semiconductor device having a multilayer wiring structure, a conductive layer having a curved surface is used in connection between conductive layers used for the wirings. The top of a conductive layer in a lower layer exposed by removal of an insulating layer therearound has a curved surface, so that coverage of the conductive layer in the lower layer with a conductive layer in an upper layer stacked thereover can be favorable. A conductive layer is etched using a resist mask having a curved surface, so that a conductive layer having a curved surface is formed.

Abstract: A first conductive film overlapping with an oxide semiconductor film is formed over a gate insulating film, a gate electrode is formed by selectively etching the first conductive film using a resist subjected to electron beam exposure, a first insulating film is formed over the gate insulating film and the gate electrode, removing a part of the first insulating film while the gate electrode is not exposed, an anti-reflective film is formed over the first insulating film, the anti-reflective film, the first insulating film and the gate insulating film are selectively etched using a resist subjected to electron beam exposure, and a source electrode in contact with one end of the oxide semiconductor film and one end of the first insulating film and a drain electrode in contact with the other end of the oxide semiconductor film and the other end of the first insulating film are formed.

Abstract: A semiconductor device includes a first insulating layer over a substrate, a first metal oxide layer over the first insulating layer, an oxide semiconductor layer over the first metal oxide layer, a second metal oxide layer over the oxide semiconductor layer, a gate insulating layer over the second metal oxide layer, a second insulating layer over the second metal oxide layer, and a gate electrode layer over the gate insulating layer. The gate insulating layer includes a region in contact with a side surface of the gate electrode layer. The second insulating layer includes a region in contact with the gate insulating layer. The oxide semiconductor layer includes first to third regions. The first region includes a region overlapping with the gate electrode layer. The second region, which is between the first and third regions, includes a region overlapping with the gate insulating layer or the second insulating layer.

Abstract: A miniaturized transistor having excellent electrical characteristics is provided with high yield. Further, a semiconductor device including the transistor and having high performance and high reliability is manufactured with high productivity. In a semiconductor device including a transistor in which an oxide semiconductor film including a channel formation region and low-resistance regions between which the channel formation region is sandwiched, a gate insulating film, and a gate electrode layer whose top surface and side surface are covered with an insulating film including an aluminum oxide film are stacked, a source electrode layer and a drain electrode layer are in contact with part of the oxide semiconductor film and the top surface and a side surface of the insulating film including an aluminum oxide film.

Abstract: A semiconductor device with favorable electrical characteristics is provided. The semiconductor device includes an insulating layer, a semiconductor layer over the insulating layer, a source electrode layer and a drain electrode layer electrically connected to the semiconductor layer, a gate insulating film over the semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode layer overlapping with part of the semiconductor layer, part of the source electrode layer, and part of the drain electrode layer with the gate insulating film therebetween. A cross section of the semiconductor layer in the channel width direction is substantially triangular or substantially trapezoidal. The effective channel width is shorter than that for a rectangular cross section.

Abstract: To provide a highly reliable semiconductor device using an oxide semiconductor. The semiconductor device includes a first electrode layer; a second electrode layer positioned over the first electrode layer and including a stacked-layer structure of a first conductive layer and a second conductive layer; and an oxide semiconductor film and an insulating film positioned between the first electrode layer and the second electrode layer in a thickness direction. The first conductive layer and the insulating film have a first opening portion in a region overlapping with the first electrode layer, The oxide semiconductor film has a second opening portion in a region overlapping with the first opening portion. The second conductive layer is in contact with the first electrode layer exposed in the first opening portion and the second opening portion.

Abstract: A semiconductor device which includes a transistor having a miniaturized structure is provided. A first insulator is provided over a stack in which a semiconductor, a first conductor, and a second conductor are stacked in this order. Over the first insulator, an etching mask is formed. Using the etching mask, the first insulator and the second conductor are etched until the first conductor is exposed. After etching the first conductor until the semiconductor is exposed so as to form a groove having a smaller width than the second conductor, a second insulator and a third conductor are formed sequentially.

Abstract: A semiconductor device includes a first insulating layer over a substrate, a first metal oxide layer over the first insulating layer, an oxide semiconductor layer over the first metal oxide layer, a second metal oxide layer over the oxide semiconductor layer, a gate insulating layer over the second metal oxide layer, a second insulating layer over the second metal oxide layer, and a gate electrode layer over the gate insulating layer. The gate insulating layer includes a region in contact with a side surface of the gate electrode layer. The second insulating layer includes a region in contact with the gate insulating layer. The oxide semiconductor layer includes first to third regions. The first region includes a region overlapping with the gate electrode layer. The second region, which is between the first and third regions, includes a region overlapping with the gate insulating layer or the second insulating layer.

Abstract: A semiconductor device using oxide semiconductor with favorable electrical characteristics, or a highly reliable semiconductor device is provided. A semiconductor device is manufactured by: forming an oxide semiconductor layer over an insulating surface; forming source and drain electrodes over the oxide semiconductor layer; forming an insulating film and a conductive film in this order over the oxide semiconductor layer and the source and drain electrodes; etching part of the conductive film and insulating film to form a gate electrode and a gate insulating layer, and etching part of the upper portions of the source and drain electrodes to form a first covering layer containing a constituent element of the source and drain electrodes and in contact with the side surface of the gate insulating layer; oxidizing the first covering layer to form a second covering layer; and forming a protective insulating layer containing an oxide over the second covering layer.

Abstract: A miniaturized transistor, a transistor with low parasitic capacitance, a transistor with high frequency characteristics, or a semiconductor device including the transistor is provided. The semiconductor device includes a first insulator, an oxide semiconductor over the first insulator, a first conductor and a second conductor that are in contact with the oxide semiconductor, a second insulator that is over the first and second conductors and has an opening reaching the oxide semiconductor, a third insulator over the oxide semiconductor and the second insulator, and a fourth conductor over the third insulator. The first conductor includes a first region and a second region. The second conductor includes a third region and a fourth region. The second region faces the third region with the first conductor and the first insulator interposed therebetween. The second region is thinner than the first region. The third region is thinner than the fourth region.

Abstract: To provide a semiconductor device which occupies a small area and is highly integrated. The semiconductor device includes an oxide semiconductor layer, an electrode layer, and a contact plug. The electrode layer includes one end portion in contact with the oxide semiconductor layer and the other end portion facing the one end portion. The other end portion includes a semicircle notch portion when seen from the above. The contact plug is in contact with the semicircle notch portion.

Abstract: A miniaturized transistor having excellent electrical characteristics is provided with high yield. Further, a semiconductor device including the transistor and having high performance and high reliability is manufactured with high productivity. In a semiconductor device including a transistor in which an oxide semiconductor film including a channel formation region and low-resistance regions between which the channel formation region is sandwiched, a gate insulating film, and a gate electrode layer whose top surface and side surface are covered with an insulating film including an aluminum oxide film are stacked, a source electrode layer and a drain electrode layer are in contact with part of the oxide semiconductor film and the top surface and a side surface of the insulating film including an aluminum oxide film.

Abstract: A semiconductor device with favorable electrical characteristics is provided. The semiconductor device includes an insulating layer, a semiconductor layer over the insulating layer, a source electrode layer and a drain electrode layer electrically connected to the semiconductor layer, a gate insulating film over the semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode layer overlapping with part of the semiconductor layer, part of the source electrode layer, and part of the drain electrode layer with the gate insulating film therebetween. A cross section of the semiconductor layer in the channel width direction is substantially triangular or substantially trapezoidal. The effective channel width is shorter than that for a rectangular cross section.

Abstract: The on-state characteristics of a transistor are improved and thus, a semiconductor device capable of high-speed response and high-speed operation is provided. A highly reliable semiconductor device showing stable electric characteristics is made. The semiconductor device includes a transistor including a first oxide layer; an oxide semiconductor layer over the first oxide layer; a source electrode layer and a drain electrode layer in contact with the oxide semiconductor layer; a second oxide layer over the oxide semiconductor layer; a gate insulating layer over the second oxide layer; and a gate electrode layer over the gate insulating layer. An end portion of the second oxide layer and an end portion of the gate insulating layer overlap with the source electrode layer and the drain electrode layer.

Abstract: To give favorable electrical characteristics to a semiconductor device. The semiconductor device includes an insulating layer, a semiconductor layer over the insulating layer, a pair of electrodes over the semiconductor layer and each electrically connected to the semiconductor layer, a gate electrode over the semiconductor layer, and a gate insulating layer between the semiconductor layer and the gate electrode. The insulating layer includes an island-shaped projecting portion. A top surface of the projecting portion of the insulating layer is in contact with a bottom surface of the semiconductor layer, and is positioned on an inner side of the semiconductor layer when seen from above. The pair of electrodes covers part of a top surface and part of side surfaces of the semiconductor layer. Furthermore, the gate electrode and the gate insulating layer cover side surfaces of the projecting portion of the insulating layer.

Abstract: A semiconductor device includes a first insulating layer over a substrate, a first metal oxide layer over the first insulating layer, an oxide semiconductor layer over the first metal oxide layer, a second metal oxide layer over the oxide semiconductor layer, a gate insulating layer over the second metal oxide layer, a second insulating layer over the second metal oxide layer, and a gate electrode layer over the gate insulating layer. The gate insulating layer includes a region in contact with a side surface of the gate electrode layer. The second insulating layer includes a region in contact with the gate insulating layer. The oxide semiconductor layer includes first to third regions. The first region includes a region overlapping with the gate electrode layer. The second region, which is between the first and third regions, includes a region overlapping with the gate insulating layer or the second insulating layer.

Abstract: To provide a highly reliable semiconductor device using an oxide semiconductor. The semiconductor device includes a first electrode layer; a second electrode layer positioned over the first electrode layer and including a stacked-layer structure of a first conductive layer and a second conductive layer; and an oxide semiconductor film and an insulating film positioned between the first electrode layer and the second electrode layer in a thickness direction. The first conductive layer and the insulating film have a first opening portion in a region overlapping with the first electrode layer, The oxide semiconductor film has a second opening portion in a region overlapping with the first opening portion. The second conductive layer is in contact with the first electrode layer exposed in the first opening portion and the second opening portion.

Abstract: To provide a semiconductor device which occupies a small area and is highly integrated. The semiconductor device includes an oxide semiconductor layer, an electrode layer, and a contact plug. The electrode layer includes one end portion in contact with the oxide semiconductor layer and the other end portion facing the one end portion. The other end portion includes a semicircle notch portion when seen from the above. The contact plug is in contact with the semicircle notch portion.

Abstract: First to third insulators are successively formed in this order over a first conductor over a semiconductor substrate; a hard mask with a first opening is formed thereover; a resist mask with a second opening is formed thereover; a third opening is formed in the third insulator; a fourth opening is formed in the second insulator; the resist mask is removed; a fifth opening is formed in the first to third insulators; a second conductor is formed to cover an inner wall and a bottom surface of the fifth opening; a third conductor is formed thereover; polishing treatment is performed so that the hard mask is removed, and that levels of top surfaces of the second and third conductors and the third insulator are substantially equal to each other; and an oxide semiconductor is formed thereover. The second insulator is less permeable to hydrogen than the first and third insulators, the second conductor is less permeable to hydrogen than the third conductor.

Abstract: The semiconductor device includes a first layer including a first transistor, a second layer including a first insulating film over the first layer, a third layer including a second insulating film over the second layer, and a fourth layer including a second transistor over the third layer. A first conductive film electrically connects the first transistor and the second transistor to each other through an opening provided in the first insulating film. A second conductive film electrically connects the first transistor, the second transistor, and the first conductive film to one another through an opening provided in the second insulating film. A channel formation region of the first transistor includes a single crystal semiconductor. A channel formation region of the second transistor includes an oxide semiconductor. The width of a bottom surface of the second conductive film is 5 nm or less.