Semiconductor device and manufacturing method thereof
First Claim
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1. A method for manufacturing a semiconductor device comprising the steps of:
- forming an insulating film on a semiconductor layer;
forming a first conductive film on the insulating film;
forming a second conductive film on the first conductive film;
forming a resist pattern on the second conductive film having end portions and a middle portion that are thicker than remaining portions of the resist pattern from a cross-sectional view;
etching the second conductive film and the first conductive film to form a first conductive pattern from the first conductive film and a plurality of second conductive patterns from the second conductive film, the second conductive patterns being located apart from each other on the first conductive pattern; and
forming a plurality of channel forming regions, a plurality of first impurity regions, a plurality of second impurity regions and a plurality of third impurity regions in the semiconductor layer by doping an impurity element imparting one conductivity,wherein each of the first impurity regions is located outside the first conductive pattern, each of the second impurity regions is overlapped with the first conductive pattern, and each of the third impurity regions is located between two of the channel forming regions, andwherein the number of the second conductive patterns and the number of the channel forming regions are the same and the number is at least three.
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Abstract
It is an object of the present invention to form a plurality of elements in a limited area to reduce the area occupied by the elements for integration so that further higher resolution (increase in number of pixels), reduction of each display pixel pitch with miniaturization, and integration of a driver circuit that drives a pixel portion can be advanced in semiconductor devices such as liquid crystal display devices and light-emitting devices that has EL elements. A photomask or a reticle provided with an assist pattern that is composed of a diffraction grating pattern or a semi-transparent film and has a function of reducing a light intensity is applied to a photolithography process for forming a gate electrode to form a complicated gate electrode. In addition, a top-gate TFT that has the multi-gate structure described above and a top gate TFT that has a single-gate structure can be formed on the same substrate just by changing the mask without increasing the number of processes.
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Citations
33 Claims
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1. A method for manufacturing a semiconductor device comprising the steps of:
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forming an insulating film on a semiconductor layer; forming a first conductive film on the insulating film; forming a second conductive film on the first conductive film; forming a resist pattern on the second conductive film having end portions and a middle portion that are thicker than remaining portions of the resist pattern from a cross-sectional view; etching the second conductive film and the first conductive film to form a first conductive pattern from the first conductive film and a plurality of second conductive patterns from the second conductive film, the second conductive patterns being located apart from each other on the first conductive pattern; and forming a plurality of channel forming regions, a plurality of first impurity regions, a plurality of second impurity regions and a plurality of third impurity regions in the semiconductor layer by doping an impurity element imparting one conductivity, wherein each of the first impurity regions is located outside the first conductive pattern, each of the second impurity regions is overlapped with the first conductive pattern, and each of the third impurity regions is located between two of the channel forming regions, and wherein the number of the second conductive patterns and the number of the channel forming regions are the same and the number is at least three. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for manufacturing a semiconductor device comprising the steps of:
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forming an insulating film on a semiconductor layer; forming a first conductive film on the insulating film; forming a second conductive film on the first conductive film; forming a resist pattern on the second conductive film having end portions and a middle portion that are thicker than remaining portions of the resist pattern from a cross-sectional view; etching the second conductive film and the first conductive film to form a first conductive pattern from the first conductive film and a plurality of second conductive patterns from the second conductive film, the second conductive patterns being located apart from each other on the first conductive pattern; forming a plurality of channel forming regions, a plurality of first impurity regions, a plurality of second impurity regions and a plurality of third impurity regions in the semiconductor layer by doping an impurity element imparting one conductivity; forming a third insulating film over the first conductive pattern and the plurality of second conductive patterns; forming a source electrode and a drain electrode each electrically connected to the first impurity regions via the third insulating film; and forming a pixel electrode connected to one of the source electrode and the drain electrode, wherein each of the first impurity regions is located outside the first conductive pattern, each of the second impurity regions is overlapped with the first conductive pattern, and each of the third impurity regions is located between two of the channel forming regions, and wherein the number of the second conductive patterns and the number of the channel forming regions are the same and the number is at least three. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for manufacturing a semiconductor device comprising the steps of:
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forming an insulating film on a semiconductor layer; forming a first conductive film on the insulating film; forming a second conductive film on the first conductive film; forming a resist pattern on the second conductive film, the resist pattern having three portions that are thicker in thickness as compared with remaining portions of the resist pattern, wherein, in the three portions, a length of a middle portion of the resist pattern is longer than that of end portions of the resist pattern; etching the second conductive film and the first conductive film to form a first conductive pattern from the first conductive film and a plurality of second conductive patterns from the second conductive film, the second conductive patterns being located apart from each other on the first conductive pattern; and forming a plurality of channel forming regions, a plurality of first impurity regions, a plurality of second impurity regions and a plurality of third impurity regions in the semiconductor layer by doping an impurity element imparting one conductivity, wherein each of the first impurity regions is located outside the first conductive pattern, each of the second impurity regions is overlapped with the first conductive pattern, and each of the third impurity regions is located between two of the channel forming regions, and wherein the number of the second conductive patterns and the number of the channel forming regions are the same and the number is at least three. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification
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Current AssigneeSemiconductor Energy Laboratory Co., Ltd.
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Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
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InventorsKomori, Shigeki, Osame, Mitsuaki, Ohnuma, Hideto, Yamazaki, Shunpei, Sakakura, Masayuki, Nagai, Masaharu
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Primary Examiner(s)LEE, HSIEN MING
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Application NumberUS12/534,176Publication NumberTime in Patent Office659 DaysField of Search438/149, 438151-155, 438/162, 438/164US Class Current438/149CPC Class CodesH01L 27/1214 comprising a plurality of T...H01L 27/124 with a particular compositi...H01L 27/1251 comprising TFTs having a di...H01L 27/1288 employing particular maskin...H01L 27/14623 Optical shieldingH01L 29/78645 with multiple gateH10K 59/12 Active-matrix OLED [AMOLED]...
