Method for etching photolithographic substrates
View Patent ↗The present invention provides a method for processing a photolithographic substrate within a vacuum chamber. The method comprising the steps of cooling the photolithographic substrate to a target temperature before the photolithographic substrate is processed within the vacuum chamber. At least one processing gas is introduced into the vacuum chamber. After the photolithographic substrate is at the target temperature, a plasma is ignited from the processing gas wherein the photolithographic substrate is processed using the plasma. Upon completion of the processing, the photolithographic substrate is unloaded from the vacuum chamber.
1. A method for processing a photolithographic substrate, comprising:
loading the photolithographic substrate into a vacuum chamber;
cooling the photolithographic substrate to a target temperature, said substrate is not actively clamped during said cooling step;
introducing at least one processing gas into said vacuum chamber;
igniting a plasma from said processing gas after said cooling step;
processing the photolithographic substrate using said plasma, said substrate is not actively cooled during said processing step; and
unloading the photolithographic substrate from said vacuum chamber.
2. The method according to claim 1 wherein said photolithographic substrate is a binary Cr photomask.
3. The method according to claim 1 wherein said target temperature is in a range of less than about minus thirty degrees Celsius.
4. The method according to claim 1 wherein said photolithographic substrate is a phase shift photomask.
5. The method according to claim 4 wherein said phase shift photomask is an embedded attenuating phase shift mask.
6. The method according to claim 1 wherein said processing is plasma etching.
7. The method according to claim 6 wherein said processing gas further comprising a chlorine containing gas and an oxygen containing gas.
8. The method according to claim 7 wherein said chlorine containing gas and said oxygen containing gas are introduced into the vacuum chamber at a ratio of greater than about fifteen to one.
9. The method according to claim 1 further comprising modulating the processing of the photolithographic substrate based on time.
10. The method according to claim 9 wherein said modulation is amplitude modulation.
11. The method according to claim 9 wherein said modulation is pulse modulation.
12. A method of etching a photolithographic substrate, comprising:
loading the photolithographic substrate onto a substrate support within a vacuum chamber;
introducing at least one processing gas into said vacuum chamber;
igniting a first plasma from said processing gas;
etching the photolithographic substrate for a first set of process conditions using said first plasma;
cooling the photolithographic substrate to a target temperature, said substrate is not actively clamped during said cooling step;
igniting a second plasma from said processing gas after said cooling step;
etching the photolithographic substrate for a second set of process conditions using said second plasma, said substrate is not actively cooled during said etching step; and
unloading the photolithographic substrate from said vacuum chamber.
13. The method according to claim 12 wherein said cooling step occurs in a second chamber.
14. The method according to claim 12 wherein said cooling step occurs in said vacuum chamber.
15. The method according to claim 12 wherein said photolithographic substrate is a binary Cr photomask.
16. The method according to claim 15 wherein said first set of process conditions using said first plasma etches an antireflective layer of said photolithographic substrate.
17. The method according to claim 16 further comprising stripping a photoresist layer prior to etching the remaining Cr on said photolithographic substrate.