US 12,322,571 B2
Multi-state RF pulsing to control mask shape and breaking selectivity versus process margin trade-off
Nikhil Dole, Union City, CA (US); Vikhram Vilasur Swaminathan, Redwood City, OR (US); Beibei Jiang, Fremont, CA (US); and Merrett Wong, San Carlos, CA (US)
Assigned to Lam Research Corporation, Fremont, CA (US)
Appl. No. 17/634,547
Filed by Lam Research Corporation, Fremont, CA (US)
PCT Filed Aug. 21, 2020, PCT No. PCT/US2020/047370
§ 371(c)(1), (2) Date Feb. 11, 2022,
PCT Pub. No. WO2021/035132, PCT Pub. Date Feb. 25, 2021.
Claims priority of provisional application 62/909,781, filed on Oct. 3, 2019.
Claims priority of provisional application 62/890,285, filed on Aug. 22, 2019.
Prior Publication US 2022/0285130 A1, Sep. 8, 2022
Int. Cl. H01J 37/32 (2006.01)
CPC H01J 37/32146 (2013.01) [H01J 37/32165 (2013.01); H01J 37/32935 (2013.01); H01J 2237/3346 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A method for performing an etch process on a substrate in a plasma processing system, comprising:
applying source RF power to an electrode of the plasma processing system; and
applying bias RF power to the electrode;
wherein the source RF power and the bias RF power are pulsed signals that together define a plurality of multi-state pulsed RF cycles, each cycle having a first state, a second state, and a third state;
wherein the first state is defined by the source RF power having a first source RF power level and the bias RF power having a first bias RF power level;
wherein the second state is defined by the source RF power having a zero power level and the bias RF power having a zero power level;
wherein the third state is defined by the source RF power having a second source RF power level less than the first source RF power level to effect an energy state defined to assist in removal of material from a neck of a feature being etched with selectivity to a mask, and the bias RF power having a zero power level during said third state, and
wherein duration of each of the first state, the second state and the third state are scalable based on aspect ratio of the feature being etched.