Device and method for etching nitride spacers formed upon an integrated circuit gate conductor
AssigneeAdvanced Micro Devices, Inc.
InventorsThien T. Nguyen, Mark I. Gardner, Charles E. May
Life of this patent
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Abstract
A dry etch method is presented wherein a semiconductor substrate is introduced between a first electrode and a second electrode maintained within a reaction chamber. In this method, a main etch step is performed in which a first quantity of low frequency power is applied to the pair of electrodes from an RF power source. A first gas flow is circulated through the reaction chamber during the application of power. This first gas flow includes a first argon flow, a first oxygen flow, and a first fluorocarbon flow. Applying the first quantity of low frequency power creates a first plasma for etching a portion of a nitride layer arranged above the semiconductor substrate.
Claims25
A dry etch method, comprising:
- introducing a semiconductor substrate between a pair of electrodes maintained within a reaction chamber;
- applying a first quantity of low frequency power to the pair of electrodes from an RF power source while a first gas flow is circulated through the reaction chamber, the first gas flow comprising a first inert gas flow, a first oxygen flow, and a first fluorocarbon flow, wherein the ratio of fluorine atoms to carbon atoms within the first fluorocarbon flow is less than 4:1, and wherein said applying a first quantity of low frequency power creates a first plasma;
- etching a portion of a nitride layer arranged above the semiconductor substrate with the first plasma;
- terminating applying a first quantity of low frequency power subsequent to etching a portion of a nitride layer;
- applying a second quantity of low frequency power from the RF power source to the pair of electrodes while a second gas flow is circulated through the reaction chamber, the second gas flow comprising a second inert gas flow and a second fluorocarbon flow, and wherein the ratio of fluorine atoms to carbon atoms within the second fluorocarbon flow is less than the ratio of fluorine atoms to carbon atoms within the first fluorocarbon flow, and wherein said applying a second quantity of low frequency power creates a second plasma;
- and
- etching a portion of an oxide layer disposed beneath the nitride layer and above the semiconductor substrate with the second plasma.
A dry etch method, comprising:
- positioning a semiconductor substrate on the first electrode of a pair of electrodes maintained within a reaction chamber, wherein the electrodes are parallel and spaced from each other by a gap;
- first fixing the gap between the electrodes at about 0.9-1.1 cm;
- first circulating a first gas flow through the reaction chamber, wherein the first gas flow comprises a first Ar flow at a first Ar flow rate of about 300-400 sccm, a first O2 flow at a first O2 flow rate of about 14.4-17.6 sccm, a first CHF3 flow at a first CHF3 flow rate of about 22.5-27.5 sccm, and a first CF4 flow at a first CF4 flow rate of about 45-55 sccm;
- first setting the pressure within the reaction chamber at about 720-880 mT;
- first applying about 270-330 watts of power at a frequency of about 360-440 kHz to create a first plasma;
- and
- etching a portion of a nitride layer arranged above the semiconductor substrate with the first plasma;
- terminating said applying about 270-330 watts of power;
- second fixing the gap between the electrodes at about 1.0-1.2 cm;
- second circulating a second gas flow through the reaction chamber, wherein the second gas flow comprises a second Ar flow at a second Ar flow rate of about 350-450 sccm, a second CHF3 flow at a second CHF3 flow rate of about 31.5-38.5 sccm, and a second CF4 flow at a second CF4 flow rate of about 13.5-16.5 sccm;
- second setting the pressure within the chamber to about 180-220 mT;
- and
- second applying about 180-220 watts of power at a frequency of about 360-440 kHz to create a second plasma;
- and
- etching a portion of an oxide layer disposed beneath the nitride layer and above the semiconductor substrate with the second plasma.
A semiconductor fabrication process, comprising:
- performing a first dry etch process on a semiconductor topography, wherein the first dry etch process is selective to nitride over oxide;
- terminating the first dry etch process;
- and
- performing a second dry etch process on the semiconductor topography, wherein the second etch process is selective to oxide over silicon.
Dependencies are inferred from the claim text.