High ion energy and reative species partial pressure plasma ash process
AssigneeInternational Business Machines Corporation
InventorsNicholas C. M. Fuller, Timothy J. Dalton
Life of this patent
Estimating the term…
Abstract
A high ion energy and high pressure O2/CO-based plasma for ashing field photoresist material subsequent to via-level damascene processing. The optimized plasma ashing process is performed at greater than approximately 300 mT pressure and ion energy greater than approximately 500 W conditions with an oxygen partial pressure of greater than approximately 85%. The rapid ash rate of the high pressure/high ion energy process and minimal dissociation conditions (no “source” power is applied) allow minimal interaction between the interlevel dielectric and ash chemistry to achieve minimal overall sidewall modification of less than approximately 5 nm.
Claims20
A method of forming a semiconductor interconnect structure having a modified layer of minimal thickness comprising the steps of:
- providing an organosilicate glass structure having conductive features;
- providing a photoresist covering at least a portion of said organosilicate glass structure and where at least a portion of said organosilicate glass structure is not covered by said photoresist;
- removing said photoresist with a high energy reactive species partial pressure plasma ash process, wherein said plasma ash process comprises O2, CO or CO2 or combinations thereof and has an input bias power/oxygen partial pressure ratio less than approximately 2.0 W/mT−1, said input bias has a power of approximately 200 W to approximately 600 W and a frequency less than or equal to 13.56 MHz, and has a source power of less than approximately 50 W and thereby providing said organosilicate glass structure not covered by said photoresist with a minimal modified thickness.
A method of forming a semiconductor interconnect structure having a modified layer of minimal thickness comprising the steps of:
- providing an organosilicate glass structure having conductive features;
- providing a photoresist covering at least a portion of said organosilicate glass structure and where at least a portion of said organosilicate glass structure is not covered by said photoresist;
- removing said photoresist with a high energy reactive species partial pressure plasma ash process, wherein said high energy reactive species partial pressure plasma ash process comprises O2, CO or CO2 or combinations thereof and thereby providing said organosilicate glass structure not covered by said photoresist with a minimal modified thickness wherein the percentage of dissociation of said plasma ash is less than approximately 10%.
A method of forming a semiconductor interconnect structure having a modified layer of minimal thickness comprising the steps of:
- providing an organosilicate glass structure having conductive features;
- providing a photoresist covering at least a portion of said organosilicate glass structure and where at least a portion of said organosilicate glass structure is not covered by said photoresist;
- removing said photoresist with a high energy reactive species partial pressure plasma ash process, wherein said plasma ash process comprises N2 and H2 or NH3 and has an input bias power less than approximately 300 W and an input bias frequency less than or equal to 13.56 MHz and a source power less than approximately 50 W and thereby providing said organosilicate glass structure not covered by said photoresist with a minimal modified thickness.
A plasma ash composition consisting essentially of:
- a O2, CO or CO2, or combination thereof, based plasma with a pressure greater than approximately 300 mT;
- a high ion energy between approximately 200 W to approximately 600 W and approximately 2 MHz frequency;
- a small input bias power to oxygen partial pressure ratio of less than approximately 2.0 W/mT;
- and
- an oxygen partial pressure greater than approximately 85%.
Dependencies are inferred from the claim text.