Method for manufacturing LCD with reduced mask count
First Claim
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1. A method for manufacturing a semiconductor device, comprising the steps of:
- forming a transparent conductive film and a first metal film sequentially over a substrate;
forming a first resist by using a first photomask which is a multi-tone mask, the first resist having different thicknesses in a first portion and in a second portion;
forming a gate electrode by shaping the transparent conductive film and the first metal film with the first resist so that a stack of the transparent conductive film and the first metal film is left in the first portion and only the transparent conductive film is left in the second portion;
forming an insulating film over the gate electrode;
forming a microcrystalline silicon film as a third semiconductor film over the insulating film by microwave plasma CVD with a frequency of greater than or equal to 1 GHz;
forming a first semiconductor film, a second semiconductor film, and a second metal film sequentially over the third semiconductor film;
forming a second resist by using a second photomask which is a multi-tone mask, the second resist having different thicknesses in a channel region formation portion and in a source region formation portion and a drain region formation portion;
forming a third semiconductor layer, a first semiconductor layer, a second semiconductor layer, and a second metal layer by shaping the third semiconductor film, the first semiconductor film, the second semiconductor film, and the second metal film, respectively, with the second resist;
forming a channel region, a source region, a drain region, a source wiring, and a drain wiring of a thin film transistor by etching the third semiconductor layer, the first semiconductor layer, the second semiconductor layer, and the second metal layer;
forming a protective film over the thin film transistor; and
forming a pixel electrode over the protective film.
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Abstract
The number of photomasks is reduced in a method for manufacturing a liquid crystal display device which operates in a fringe field switching mode, whereby a manufacturing process is simplified and manufacturing cost is reduced. A first transparent conductive film and a first metal film are sequentially stacked over a light-transmitting insulating substrate; the first transparent conductive film and the first metal film are shaped using a multi-tone mask which is a first photomask; an insulating film, a first semiconductor film, a second semiconductor film, and a second metal film are sequentially stacked; the second metal film and the second semiconductor film are shaped using a multi-tone mask which is a second photomask; a protective film is formed; the protective film is shaped using a third photomask; a second transparent conductive film is formed; and the second transparent conductive film is shaped using a fourth photomask.
71 Citations
29 Claims
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1. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a transparent conductive film and a first metal film sequentially over a substrate; forming a first resist by using a first photomask which is a multi-tone mask, the first resist having different thicknesses in a first portion and in a second portion; forming a gate electrode by shaping the transparent conductive film and the first metal film with the first resist so that a stack of the transparent conductive film and the first metal film is left in the first portion and only the transparent conductive film is left in the second portion; forming an insulating film over the gate electrode; forming a microcrystalline silicon film as a third semiconductor film over the insulating film by microwave plasma CVD with a frequency of greater than or equal to 1 GHz; forming a first semiconductor film, a second semiconductor film, and a second metal film sequentially over the third semiconductor film; forming a second resist by using a second photomask which is a multi-tone mask, the second resist having different thicknesses in a channel region formation portion and in a source region formation portion and a drain region formation portion; forming a third semiconductor layer, a first semiconductor layer, a second semiconductor layer, and a second metal layer by shaping the third semiconductor film, the first semiconductor film, the second semiconductor film, and the second metal film, respectively, with the second resist; forming a channel region, a source region, a drain region, a source wiring, and a drain wiring of a thin film transistor by etching the third semiconductor layer, the first semiconductor layer, the second semiconductor layer, and the second metal layer; forming a protective film over the thin film transistor; and forming a pixel electrode over the protective film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 27)
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11. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a first transparent conductive film and a first metal film sequentially over a substrate; forming a first resist by using a first photomask which is a multi-tone mask, the first resist having different thicknesses in a first portion and in a second portion; forming a gate electrode by shaping the first transparent conductive film and the first metal film with the first resist so that a stack of the first transparent conductive film and the first metal film is left in the first portion and only the first transparent conductive film is left in the second portion; forming an insulating film over the gate electrode; forming a microcrystalline silicon film as a third semiconductor film over the insulating film by microwave plasma CVD with a frequency of greater than or equal to 1 GHz; forming a first semiconductor film, a second semiconductor film, and a second metal film sequentially over the third semiconductor film; forming a second resist by using a second photomask which is a multi-tone mask, the second resist having different thicknesses in a channel region formation portion and in a source region formation portion and a drain region formation portion; forming a third semiconductor layer, a first semiconductor layer, a second semiconductor layer, and a second metal layer by shaping the third semiconductor film, the first semiconductor film, the second semiconductor film, and the second metal film, respectively, with the second resist; ashing the second resist to form a third resist; forming a channel region, a source region, a drain region, a source wiring, and a drain wiring of a thin film transistor by etching the third semiconductor layer, the first semiconductor layer, the second semiconductor layer, and the second metal layer with the third resist; forming a protective film over the thin film transistor; forming a fourth resist in a region so as not to cover a contact hole formation portion by using a third photomask; forming a contact hole in the protective film by shaping the protective film with the fourth resist; forming a second transparent conductive film over the protective film; forming a fifth resist in a pixel electrode formation portion by using a fourth photomask; and forming a pixel electrode by shaping the second transparent conductive film with the fifth resist. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 28)
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21. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a gate electrode; forming an insulating film over the gate electrode; forming a microcrystalline silicon film as a third semiconductor film over the insulating film by microwave plasma CVD with a frequency of greater than or equal to 1 GHz; forming a first semiconductor film, a second semiconductor film, and a metal film sequentially over the third semiconductor film; forming a resist by using a photomask which is a multi-tone mask, the resist having different thicknesses in a channel region formation portion and in a source region formation portion and a drain region formation portion; forming a third semiconductor layer, a first semiconductor layer, a second semiconductor layer, and a metal layer by shaping the third semiconductor film, the first semiconductor film, the second semiconductor film, and the metal film, respectively, with the resist; and forming a channel region, a source region, a drain region, a source wiring, and a drain wiring of a thin film transistor by etching the third semiconductor layer, the first semiconductor layer, the second semiconductor layer, and the metal layer. - View Dependent Claims (22, 23, 24, 25, 26, 29)
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Current AssigneeSemiconductor Energy Laboratory Co., Ltd.
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Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
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InventorsFujikawa, Saishi, Chiba, Yoko
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Primary Examiner(s)Lee, Hsien Ming
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Assistant Examiner(s)Swanson, Walter H
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Application NumberUS12/325,584Publication NumberTime in Patent Office1,387 DaysField of Search438/30, 438/34, 438/151, 438/158, 438/481, 438/482, 438/786, 257/E21.412, 257/E21.002, 257/57, 257/59, 257/66, 257/72, 257/E21.131, 257/E21.267, 257/E21.414, 257/E21.561, 257/E29.003, 257/E29.004, 257/E29.273, 257/E29.291, 257/E29.294, 257/E33.003, 257/E33.004, 257/E33.053US Class Current438/30CPC Class CodesH01L 27/1214 comprising a plurality of T...H01L 27/1288 employing particular maskin...
