Semiconductor device and manufacturing method thereof
First Claim
1. A method for manufacturing a semiconductor device, comprising the steps of:
- forming a first wiring layer;
forming an insulating layer covering the first wiring layer;
forming a semiconductor layer over the insulating layer;
forming a first conductive film over the semiconductor layer, a second conductive film over the first conductive film, and a third conductive film over the second conductive film;
forming a resist mask over the third conductive film;
performing etching including at least two steps on the first to third conductive films to form a second wiring layer having a three-layer structure; and
removing the resist mask by a resist stripper after the etching step,wherein the two-step etching comprises;
a first etching process performed until at least the first conductive film is exposed, anda second etching process 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, andwherein the resist stripper has properties of corroding the second conductive film.
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Accused Products
Abstract
When a transistor having bottom gate bottom contact structure is manufactured, for example, a conductive layer constituting a source and a drain has a three-layer structure and two-step etching is performed. In the first etching process, an etching method in which the etching rates for at least the second film and the third film are high is employed, and the first etching process is performed until at least the first film is 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. The side wall of the second film is slightly etched when a resist mask is removed after the second etching process.
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Citations
24 Claims
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1. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a first wiring layer; forming an insulating layer covering the first wiring layer; forming a semiconductor layer over the insulating layer; forming a first conductive film over the semiconductor layer, a second conductive film over the first conductive film, and a third conductive film over the second conductive film; forming a resist mask over the third conductive film; performing etching including at least two steps on the first to third conductive films to form a second wiring layer having a three-layer structure; and removing the resist mask by a resist stripper after the etching step, wherein the two-step etching comprises; a first etching process performed until at least the first conductive film is exposed, and a second etching process 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 wherein the resist stripper has properties of corroding the second conductive film. - View Dependent Claims (2, 3, 4)
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5. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a semiconductor layer; forming a first conductive film over the semiconductor layer, a second conductive film over the first conductive film, and a third conductive film over the second conductive film in this order over the semiconductor layer; forming a resist mask over the third conductive film; performing etching including at least two steps on the first to third conductive films using the resist mask to form a first wiring layer having a three-layer structure; forming an insulating layer covering the first wiring layer and the semiconductor layer; forming a second wiring layer over the insulating layer to overlap with the semiconductor layer; and removing the resist mask by a resist stripper after the etching step, wherein the two-step etching comprises; a first etching process performed until the first conductive film is exposed, and a second etching process 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 wherein the resist stripper has properties of corroding the second conductive film. - View Dependent Claims (6, 7, 8)
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9. A method for manufacturing a semiconductor device, comprising the steps of:
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forming a first wiring layer; forming an insulating layer covering the first wiring layer; forming an oxide semiconductor layer over the insulating layer; forming a first conductive film over the oxide semiconductor layer, a second conductive film over the first conductive film, and a third conductive film over the second conductive film; forming a resist mask over the third conductive film; performing etching including at least two steps on the first to third conductive films to form a second wiring layer having a three-layer structure; and removing the resist mask by a resist stripper after the etching step, wherein the two-step etching comprises; a first etching process performed until at least the first conductive film is exposed, and a second etching process 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, wherein the first etching process is performed using a gas containing more chlorine than fluorine as its main component, and wherein the second etching process is performed using a gas containing more fluorine than chlorine as its main component. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for manufacturing a semiconductor device, comprising the steps of:
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forming an oxide semiconductor layer; forming a first conductive film over the oxide semiconductor layer, a second conductive film over the first conductive film, and a third conductive film over the second conductive film in this order over the oxide semiconductor layer; forming a resist mask over the third conductive film; performing etching including at least two steps on the first to third conductive films using the resist mask to form a first wiring layer having a three-layer structure; forming an insulating layer covering the first wiring layer and the oxide semiconductor layer; forming a second wiring layer over the insulating layer to overlap with the oxide semiconductor layer; and removing the resist mask by a resist stripper after the etching step, wherein the two-step etching comprises; a first etching process performed until the first conductive film is exposed, and a second etching process 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, wherein the first etching process is performed using a gas containing more chlorine than fluorine as its main component, and wherein the second etching process is performed using a gas containing more fluorine than chlorine as its main component. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification