Plasma Etching Method
OwnerYoshiyuki OOTA, Tsuyoshi Yoshida +3inventors
InventorsYoshiyuki OOTA, Tsuyoshi Yoshida, Eiji Ikegami, Kenji Imamoto, Jyunji Adachi
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Abstract
The invention provides a plasma etching method that does not create any difference in profile between sparse and dense portions of the mask pattern in processing a device having a space width equal to or smaller than 100 nm. An added gas having a high C/F ratio such as C4F8 gas capable of increasing the generation of CF2 radicals that may become sidewall protection film components having a small attachment coefficient is added to the etching gas in order to form sidewall protection films on dense pattern portions, and in addition, Xe gas is added in order to suppress dissociation effect by lowering the electron temperature.
Claims8
A plasma etching method for etching a line and space (L/S) pattern on a silicon oxide film and a silicon nitride film having a dense pattern portion and a sparse pattern portion, using a multilayer resist mask, wherein
- an etching gas composed of CF4, CHF3, CH2F2, CH3F is used as the etching gas:
- a gas for lowering an electron temperature of the plasma, of Xe gas or Kr gas, is added as a diluent gas in order to suppress excessive dissociation of the etching gas;
- a gas having a high C/F ratio compared to the etching gas, of C4F6, C4F8 and C5F8, is added in order to generate CF2 radicals having a low attachment coefficient;
- and
- the diluent gas is added to the etching gas in order to suppress excessive dissociation of the etching gas and/or to increase the ratio of CF2 radicals having a low attachment coefficient so that the dense pattern portion and the sparse pattern portion are worked uniformly.
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Dependencies are inferred from the claim text.