High lateral to vertical ratio etch process for device manufacturing
A layer stack over a substrate is etched using a photoresist pattern deposited on the layer stack as a first mask. The photoresist pattern is in-situ cured using plasma. At least a portion of the photoresist pattern can be modified by curing. In one embodiment, silicon by-products are formed on the photoresist pattern from the plasma. In another embodiment, a carbon from the plasma is embedded into the photoresist pattern. In yet another embodiment, the plasma produces an ultraviolet light to cure the photoresist pattern. The cured photoresist pattern is slimmed. The layer stack is etched using the slimmed photoresist pattern as a second mask.
1. A method to manufacture an electronic device, the method comprising:
etching a first layer stack over a substrate using a photoresist pattern deposited on the first layer stack as a first mask;
curing the photoresist pattern on the etched first layer stack using plasma, wherein a hardened crust layer is formed on a top of the photoresist pattern by curing;
slimming the cured photoresist pattern having the hardened crust layer on the top to expose the etched first layer stack; and
etching the exposed first layer stack using the slimmed photoresist pattern as a second mask.
2. The method of claim 1 , wherein the hardened crust layer includes silicon by-products produced from the plasma.
3. The method of claim 1 , wherein the hardened crust layer includes carbon produced from the plasma.
4. The method of claim 1 , wherein hardened crust layer is formed by an ultraviolet light emitted from the plasma.
5. The method of claim 1 , wherein the curing is performed during the etching.
6. The method of claim 1 , wherein the curing and the etching alternate.
7. The method of claim 1 , wherein the hardened crust layer includes elements produced by the plasma.
8. The method of claim 1 , wherein the layer stack is a part of a multi-stacked structure on the substrate, and wherein the etching using the first mask, the curing, the slimming, and the etching using the second mask are repeated until the substrate is exposed.
9. The method of claim 1 , wherein the layer stack comprises an insulating layer on a conducting layer.
10. The method of claim 1 , wherein the layer stack comprises an oxide layer on an nitride layer.
11. The method of claim 1 , wherein the layer stack comprises a first polymer layer on a second polymer layer.
12. The method of claim 1 , wherein the plasma is generated at least from a gas selected from a group consisting of CH 4 ,CH 3 F, CH 2 F 2 , CHF 3 , CF 4 , C 4 F 6 , C 4 F 8 , H 2 , or any combination thereof.
13. The method of claim 1 , wherein the plasma is generated at least from a gas selected from a group consisting of SiCl 4 , SiF 4 , SiH 4 , O 2 , N 2 , or any combination thereof.
14. The method of claim 1 , wherein the plasma is generated at least from a gas selected from a group consisting of H 2 ,C 4 F 6 ,C 4F 8 ,SF 6 ,O 2 ,CF 4 ,SO 2 , or any combination thereof.