Plasma etching method using polymer deposition and method of forming contact hole using the plasma etching method
First Claim
1. A plasma etching method, in which a dielectric film on a wafer is etched by plasma using a photoresist pattern as a mask, the method comprising:
- (a) plasma etching an upper portion of the dielectric film using the photoresist pattern as a mask by establishing an average power of a power supply within a given range, to form an opening the dielectric film;
(b) selectively depositing a polymer layer on the photoresist pattern, the polymer layer having a thick portion on the surface of the photoresist pattern and a substantially thinner portion on the surface of the opening in the dielectric film; and
(c) plasma etching the remaining portion of the dielectric film using the photoresist pattern and the polymer layer as a mask by establishing the average power of the power supply within the given range.
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Abstract
A plasma etching method using selective polymer deposition, and a method of forming a contact hole using the plasma etching method are provided. The plasma etching method uses a method of reinforcing an etch mask by selectively depositing polymer on only a photoresist pattern, which is an etch mask. That is, a dielectric film is plasma etched for a predetermined period of time using the photoresist pattern as an etch mask, and polymer is selectively deposited on only the photoresist pattern which is thinned by plasma etching, thereby forming a polymer layer. Following this, the dielectric film is plasma etched using the photoresist pattern and the polymer layer as a mask. Thus, dielectric film etching providing high resolution and an excellent profile can be performed using the thinned photoresist pattern as a mask, and a contact hole and a self-aligned contact hole each having a very high aspect ratio, and a self-aligned contact hole having an excellent profile, can be formed.
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Citations
35 Claims
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1. A plasma etching method, in which a dielectric film on a wafer is etched by plasma using a photoresist pattern as a mask, the method comprising:
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(a) plasma etching an upper portion of the dielectric film using the photoresist pattern as a mask by establishing an average power of a power supply within a given range, to form an opening the dielectric film;
(b) selectively depositing a polymer layer on the photoresist pattern, the polymer layer having a thick portion on the surface of the photoresist pattern and a substantially thinner portion on the surface of the opening in the dielectric film; and
(c) plasma etching the remaining portion of the dielectric film using the photoresist pattern and the polymer layer as a mask by establishing the average power of the power supply within the given range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A contact hole forming method comprising:
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(a) forming a dielectric film on a conductive layer on a substrate and forming a photoresist pattern on the dielectric film;
(b) plasma etching the dielectric film to form an opening therein, using the photoresist pattern as a mask by setting the average power of a bias power supply that is applied to the substrate to accelerate plasma to a high level within a defined range wherein plasma etching is more predominant than deposition of polymer;
(c) selectively forming a polymer layer on the photoresist pattern by setting the average power of the bias power supply to a low level within a defined range where polymer deposition is more predominant than plasma etching such that the polymer layer has a thick portion on the surface of the photoresist pattern and a substantially thinner portion on the surface of the opening in the dielectric film; and
(d) plasma etching the dielectric film using the photoresist pattern and the polymer layer as a mask by setting the average power of the bias power supply to the high level. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A self-aligned contact hole forming method comprising:
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(a) successively forming a first dielectric film and a conductive layer pattern on a semiconductor substrate;
(b) forming a capping layer to cover the conductive layer pattern;
(c) forming a second dielectric film overlying the conductive layer pattern and the capping layer;
(d) forming a photoresist pattern on the second dielectric film;
(e) performing primary plasma etching on the second dielectric film to form an opening therein using the photoresist pattern as a mask to expose a portion of the capping layer by establishing an average power of a power supply within a given range;
(f) selectively depositing polymer on the photoresist pattern and on the exposed capping layer the polymer layer having a thick portion on the surface of the photoresist pattern and a substantially thinner portion on the surface of the opening in the dielectric film; and
(g) performing secondary plasma etching on the second dielectric film using the photoresist pattern, the capping layer and the polymer layer on the photoresist pattern and on the capping layer as a mask by establishing the average power of the power supply within the given range. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
(e1) plasma etching the second dielectric film using the photoresist pattern as a mask by setting the average power of the bias power supply that is applied to the substrate to accelerate plasma to a high level within a defined range wherein plasma etching is more predominant than polymer deposition;
(e2) selectively forming a polymer layer on the photoresist pattern by setting the average power of the bias power supply to a low level within a defined range wherein polymer deposition is more predominant than plasma etching; and
(e3) plasma etching the second dielectric film using the photoresist pattern and the polymer layer as a mask by setting the average power of the bias power supply to the high level, wherein the capping layer is exposed by repeating steps (e2) and (e3) one or more times.
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23. The method of claim 21, wherein a contact hole that exposes the conductive layer is formed by repeating steps (f) and (g) one or more times.
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24. The method of claim 21, wherein, in step (f), the polymer layer is formed by setting the average power of the bias power supply that is applied to the substrate to accelerate plasma to a low level within a defined range wherein polymer deposition is more predominant than plasma etching.
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25. The method of claim 21, wherein, in step (f) of forming a polymer layer, the difference between the thickness of the polymer layer stacked on the photoresist pattern and the thickness of the polymer layer on the capping layer exposed by the etching of the second dielectric film is reduced by setting the temperature of the substrate to a level that is higher than that of the plasma etching steps (e) and (g).
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26. The method of claim 21, wherein, in step (f) of forming a polymer layer, the difference between the thickness of the polymer layer stacked on the photoresist pattern and the thickness of the polymer layer on the capping portion exposed by the etching of the second dielectric film is reduced by setting the internal pressure of a reactor to a level which is lower than that of the plasma etching steps (e) and (g).
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27. The method of claim 21, wherein, in step (f) of forming a polymer layer, the difference between the thickness of the polymer layer stacked on the photoresist pattern and the thickness of the polymer layer on the capping layer exposed by the etching of the second dielectric film is reduced by setting the average power of a source power supply that is applied to generate the plasma to a level that is lower than that of the plasma etching steps (e) and (g).
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28. The method of claim 21, which further comprises supplying a gas, in step (g), for etching polymer deposited by step (f) on the sidewall of the hole in the second dielectric film formed by step (e).
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29. The method of claim 28, wherein the gas for etching the polymer is O2, N2, CO or CO2.
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30. A plasma etching method, in which a dielectric film on a wafer is etched by plasma with a photoresist pattern as a mask using a plasma equipment comprising a source power supply and a bias power supply, the method comprising:
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(a) plasma etching a first portion of the dielectric film to form an opening therein, using the photoresist pattern as a mask for a first period of time;
(b) selectively depositing polymer on the photoresist pattern, thereby forming a polymer layer thereon for a second period of times the polymer layer having a thick portion on the surface of the photoresist pattern and a substantially thinner portion on the surface of the opening in the dielectric film; and
(c) plasma etching a second portion of the dielectric film using the photoresist pattern and the polymer layer as a mask for a third period of time. - View Dependent Claims (31, 32, 33)
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34. A method of forming a contact hole in a dielectric film, the method comprising:
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(a) plasma etching an opening in an upper portion of a dielectric film, using a photoresist pattern as a mask;
(b) depositing a polymer layer having a thick portion on the surface of the photoresist patter and a substantially thinner portion on the surface of the opening in the dielectric film; and
(c) thereafter plasma etching the remaining portion of the dielectric film below the opening to form a contact hole in the dielectric film, using the photoresist pattern and the thick portion of the polymer layer deposited on the photoresist pattern as a mask. - View Dependent Claims (35)
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Specification