Semiconductor device and manufacturing method thereof
First Claim
1. A method for manufacturing a semiconductor device comprising the steps of:
- forming a semiconductor layer;
stacking a first conductive film, a second conductive film, and a third conductive film in this order over the semiconductor layer; and
performing at least three-stage etching on the first to third conductive films to form a wiring layer having a three-layer structure,wherein the three-stage etching comprises;
a first etching process, which is performed until the first conductive film is exposed;
a second etching process, which is performed under a condition that an etching rate for the first conductive film is higher than the etching rate in the first etching process and an etching rate for the semiconductor layer is lower than the etching rate in the first etching process; and
a third etching process, which is performed under the condition that etching rates for the first to the third conductive films are higher than the etching rates in the second etching process.
1 Assignment
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Accused Products
Abstract
When a transistor including a conductive layer having a three-layer structure is manufactured, three-stage etching is performed. In the first etching process, an etching method in which the etching rates for the second film and the third film are high is employed, and the first etching process is performed until the first film is at least exposed. In the second etching process, an etching method in which the etching rate for the first film is higher than that in the first etching process and the etching rate for a “layer provided below and in contact with the first film” is lower than that in the first etching process is employed. In the third etching process, an etching method in which the etching rates for the first to the third films are higher than those in the second etching process is preferably employed.
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Citations
38 Claims
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1. A method for manufacturing a semiconductor device comprising the steps of:
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forming a semiconductor layer; stacking a first conductive film, a second conductive film, and a third conductive film in this order over the semiconductor layer; and performing at least three-stage etching on the first to third conductive films to form a wiring layer having a three-layer structure, wherein the three-stage etching comprises; a first etching process, which is performed until the first conductive film is exposed; a second etching process, which is performed under a condition that an etching rate for the first conductive film is higher than the etching rate in the first etching process and an etching rate for the semiconductor layer is lower than the etching rate in the first etching process; and a third etching process, which is performed under the condition that etching rates for the first to the third conductive films are higher than the etching rates in the second etching process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for manufacturing a semiconductor device comprising the steps of:
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forming a semiconductor layer; stacking a first conductive film, a second conductive film, and a third conductive film in this order over the semiconductor layer; performing at least three-stage etching on the first to third conductive films to form a first wiring layer having a three-layer structure; forming an insulating layer to cover the first wiring layer and the semiconductor layer; and forming a second wiring layer to overlap with the semiconductor layer over the insulating layer; and wherein the three-stage etching comprises; a first etching process, which is performed until the first conductive film is exposed; a second etching process, which is performed under a condition that an etching rate for the first conductive film is higher than the etching rate in the first etching process and an etching rate for the semiconductor layer is lower than the etching rate in the first etching process; and a third etching process, which is performed under the condition that etching rates for the first to the third conductive films are higher than the etching rates in the second etching process. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for manufacturing a semiconductor device comprising the steps of:
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forming a first wiring layer; forming an insulating layer to cover the first wiring layer; forming an oxide semiconductor layer over the insulating layer; stacking a first conductive film, a second conductive film, and a third conductive film in this order over the oxide semiconductor layer; and performing at least three-stage etching on the first to third conductive films to form a second wiring layer having a three-layer structure, wherein the three-stage etching comprises; a first etching process, which is performed until the first conductive film is exposed; a second etching process, which is performed under a condition that an etching rate for the first conductive film is higher than the etching rate in the first etching process and an etching rate for the oxide semiconductor layer is lower than the etching rate in the first etching process; and a third etching process, which is performed under the condition that etching rates for the first to the third conductive films are higher than the etching rates in the second etching process. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for manufacturing a semiconductor device comprising the steps of:
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forming an oxide semiconductor layer; stacking a first conductive film, a second conductive film, and a third conductive film in this order over the oxide semiconductor layer; performing at least three-stage etching on the first to third conductive films to form a first wiring layer having a three-layer structure; forming an insulating layer to cover the first wiring layer and the oxide semiconductor layer; and forming a second wiring layer to overlap with the oxide semiconductor layer over the insulating layer; and wherein the three-stage etching comprises; a first etching process, which is performed until the first conductive film is exposed; a second etching process, which is performed under a condition that an etching rate for the first conductive film is higher than the etching rate in the first etching process and an etching rate for the oxide semiconductor layer is lower than the etching rate in the first etching process; and a third etching process, which is performed under the condition that etching rates for the first to the third conductive films are higher than the etching rates in the second etching process. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification