The invention provides a method for manufacturing a TFT substrate and a TFT substrate manufactured thereof. In the above TFT substrate, the low temperature poly-silicon layer is produced by solid phase crystallization, the cost of production is under budget, and the TFT substrate is a double-grid structure that can guarantee the electrical characteristics of the thin film transistor and better the capacity of drive, and leakage phenomenon caused by groove light seldom happens.

A semiconductor device including a transistor is provided. The transistor includes a gate electrode, a first insulating film over the gate electrode, a second insulating film over the first insulating film, an oxide semiconductor film over the second insulating film, a source electrode and a drain electrode electrically connected to the oxide semiconductor film, a third insulating film over the source electrode, and a fourth insulating film over the drain electrode. A fifth insulating film including oxygen is provided over the transistor. The third insulating film includes a first portion, the fourth insulating film includes a second portion, and the fifth insulating film includes a third portion. The amount of oxygen molecules released from each of the first portion and the second portion is smaller than the amount of oxygen molecules released from the third portion when the amounts are measured by thermal desorption spectroscopy.

An oxide semiconductor device and a method for manufacturing the same are provided in the present invention. The oxide semiconductor device includes a back gate, an oxide semiconductor film, a pair of source and drain electrodes, agate insulating film, a gate electrode on the oxide semiconductor film with the gate insulating film therebetween, an insulating layer covering only over the gate electrode and the pair of source and drain electrodes, and a top blocking film over the insulating layer.

The field-effect mobility and reliability of a transistor including an oxide semiconductor film are improved. One embodiment of the present invention is a semiconductor device which includes a gate electrode, an insulating film over the gate electrode, an oxide semiconductor film over the insulating film, and a pair of electrodes over the oxide semiconductor film. The oxide semiconductor film includes a first oxide semiconductor film, a second oxide semiconductor film over the first oxide semiconductor film, and a third oxide semiconductor film over the second oxide semiconductor film. The first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film include the same element. The second oxide semiconductor film includes a region having lower crystallinity than one or both of the first oxide semiconductor film and the third oxide semiconductor film.

The method of manufacturing a semiconductor device, including preparing a semiconductor substrate, forming a first insulating layer over said semiconductor substrate, forming first grooves in the first insulating film, forming a gate electrode and a first interconnect in the first grooves, respectively, forming a gate insulating film over the gate electrode, forming a semiconductor layer over the gate insulating, forming a second insulating layer over the semiconductor layer and the first insulating film, forming a via in the second insulating layer, and forming a second interconnect such that the second interconnect is connected to the semiconductor layer through the via. The gate electrode, the first interconnect and the second interconnect are formed by Cu or Cu alloy, respectively.

A semiconductor device includes a dual-gate transistor including an oxide semiconductor film between a first gate electrode and a second gate electrode, a gate insulating film between the oxide semiconductor film and the second gate electrode, and a pair of electrodes in contact with the oxide semiconductor film. The semiconductor device further includes an insulating film over the gate insulating film, and a conductive film over the insulating film and connected to one of the pair of electrodes. The insulating film includes an opening in at least a region overlapping with the oxide semiconductor film in which the second gate electrode is provided in contact with the gate insulating film. The second gate electrode is formed using the same material as the conductive film connected to the one of the pair of electrodes.

A thin film transistor is provided as follows. A first gate electrode and a second gate electrode are stacked on each other. A semiconductor layer is interposed between the first and second gate electrodes. A source electrode and a drain electrode are interposed between the semiconductor layer and the second gate electrode. A connection electrode connects electrically the first gate electrode and the second gate electrode. A first insulating film is interposed between the first gate electrode and the semiconductor layer. A second insulating film includes a first part interposed between the semiconductor layer and the second gate electrode and a second part interposed between the second gate electrode and the drain electrode. A third insulating film includes a first part interposed between the connection electrode and the second gate electrode.

Stable electrical characteristics of a transistor including an oxide semiconductor layer are achieved. A highly reliable semiconductor device including the transistor is provided. The semiconductor device includes a multilayer film formed of an oxide layer and an oxide semiconductor layer, a gate insulating film in contact with the oxide layer, and a gate electrode overlapping with the multilayer film with the gate insulating film interposed therebetween. The oxide layer contains a common element to the oxide semiconductor layer and has a large energy gap than the oxide semiconductor layer. The composition between the oxide layer and the oxide semiconductor layer gradually changes.

The present invention provides a manufacture method of an oxide semiconductor TFT substrate and a structure thereof. The manufacture method of the dual gate oxide semiconductor TFT substrate utilizes the halftone mask to implement one photo process, which cannot only accomplish the patterning to the oxide semiconductor layer but also obtain the oxide conductor layer (53) with ion doping process; the method implements the patterning process to the bottom gate isolation layer (31) and the top gate isolation layer (32) at the same time with one photo process; the method implements patterning process to the second, third metal layers at the same time to obtain the first source (81), the first drain (82), the second source (83), the second drain (84), the first top gate (71) and the second top gate (72) with one photo process; the method implements patterning process to the second flat layer (9), the passivation layer (8) and the top gate isolation layer (32) at the same time with one photo process, to reduce the number of the photo processes to nine for effectively simplifying the manufacture process, raising the production efficiency and lowering the production cost.

A thin-film transistor substrate and a display device comprising the same are provided which can improve display quality by reducing or preventing deterioration of the characteristics of thin-film transistors. The thin-film transistor substrate comprises thin-film transistors on a lower protective metal layer. Each thin-film transistor comprises a buffer layer, a semiconductor layer, a first insulating film, a gate electrode, a second insulating film, a source electrode and a drain electrode, and a first electrode. The lower protective metal layer is electrically connected to the gate electrode and overlaps the channel region of the semiconductor layer.