Semiconductor Device and Fabrication Method Thereof
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Yasuyuki Arai, Jun Koyama
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Abstract
A p channel TFT of a driving circuit has a single drain structure and its n channel TFT, an LDD structure. A pixel TFT has the LDD structure. A pixel electrode disposed in a pixel unit is connected to the pixel TFT through a hole bored in at least a protective insulation film formed of an inorganic insulating material and formed above a gate electrode of the pixel TFT, and in an inter-layer insulation film disposed on the insulation film in close contact therewith. These process steps use 6 to 8 photo-masks.
Claims20
A method of fabricating a semiconductor device having, on the same substrate, a pixel TFT disposed in a pixel unit and a driving circuit including a p channel type TFT and an n channel type TFT and disposed round the pixel unit, comprising the steps of:
- forming an underlying film over the substrate;
- forming island-like semiconductor layers over the underlying film;
- forming n type impurity regions having a first concentration, for forming LDD regions of the n channel type TFT and the pixel TFT in a selected region of the island-like semiconductor layers;
- forming high concentration n type impurity regions for forming source regions or drain regions outside the n type impurity regions;
- forming a p type impurity region having a third concentration, for forming a source region or a drain region of the p channel type TFT in a selected region of the island-like semiconductor layers;
- forming a protective insulation film formed of an inorganic insulating material above gate electrodes of the n channel type TFT, the pixel TFT and the p channel type TFT;
- forming an inter-layer insulation film formed of an organic insulating material in contact with the protective insulation film;
- forming a conductive metal lead wire to be connected to the pixel TFT;
- and
- forming a pixel electrode comprising a transparent conductor film to be connected to the conductive metal lead wire, on the inter-layer insulation film.
A method of fabricating a semiconductor device having a liquid crystal sandwiched between a pair of substrates, comprising, the following steps for one of substrates including a pixel TFT disposed in a pixel unit and a driving circuit having a p channel type TFT and an n channel type TFT round the pixel unit:
- forming an underlying film over the one of substrates;
- forming island-like semiconductor layers over the underlying film;
- forming n type impurity regions having a first concentration, for forming LDD regions of the n channel type TFT and the pixel TFT, in a selected region of the island-like semiconductor layers;
- forming n type impurity regions having a second concentration, for forming source regions or drain regions outside the n type impurity regions having the first concentration;
- forming a p type impurity region having a third concentration, for forming a source region or a drain region of the p channel type TFT, in a selected region of the island-like semiconductor layers;
- forming a protective insulation film formed of an inorganic insulating material above gate electrodes of the n channel type TFT, the pixel TFT and the p channel type TFT;
- forming an inter-layer insulation film formed of an organic insulating material in contact with the protective insulation film;
- forming on the inter-layer insulation film a pixel electrode electrically connected to the pixel TFT through a hole in the inter-layer insulation film and in the protective insulation film;
- forming at least a transparent conductor film over the other of the substrates;
- and
- bonding the one of substrates to the other of the substrates through at least one columnar spacer formed in superposition with the hole.
A method of fabricating a semiconductor device having, on the same substrate, a pixel TFT disposed in a pixel unit and a driving circuit including an n channel type TFT and disposed round the pixel unit, the method comprising:
- forming at least two island-like semiconductor layers over the substrate;
- forming a gate electrode over each of the at least two island-like semiconductor layers;
- introducing a first n type impurity into each of the at least two island-like semiconductor layers at a first concentration by using the gate electrode as a mask;
- introducing a second n type impurity into each of the at least two island-like semiconductor layers at a second concentration by using the gate electrode as a mask and by using a resist as a mask to form an LDD region having the first concentration in the pixel TFT and the n channel type TFT and to form a source region and a drain region having the second concentration in the pixel TFT and the n channel type TFT;
- forming a protective insulation film formed of an inorganic insulating material over the gate electrode;
- activating the first n type impurity and the second n type impurity after the formation of the protective insulation film;
- and
- forming an inter-layer insulation film formed of an organic insulating material over the protective insulation film after the activation.
Dependencies are inferred from the claim text.