Hard mask stress modulation using low energy implant
Provided herein are devices and techniques for using a low-energy implant for hard mask stress modulation. In one approach, a method may include providing a stack of mandrel film layers, implanting an upper layer of the stack of mandrel film layers, and forming a mask film layer over the upper layer. The method may further include forming a patterning layer over the mask film layer, partially removing the patterning layer and the mask film layer, and patterning the stack of mandrel film layers to form a set of vertical features.
1 . A method, comprising:
providing a stack of mandrel film layers;
implanting an upper layer of the stack of mandrel film layers;
forming a mask film layer over the upper layer following the implant;
forming a patterning layer over the mask film layer;
partially removing the patterning layer and the mask film layer; and
patterning the stack of mandrel film layers to form a set of vertical features.
2 . The method of claim 1 , wherein implanting the upper layer of the stack of mandrel film layers comprises delivering ions into the upper layer while the stack of mandrel film layers is maintained at a temperature between 15-25° C.
3 . The method of claim 1 , wherein implanting the upper layer of the stack of mandrel film layers comprises delivering ions into the upper layer while the stack of mandrel film layers is maintained at a temperature between than 300-550° C.
4 . The method of claim 3 , further comprising positioning the stack of mandrel film layers atop a pedestal, wherein the pedestal is maintained at a temperature between than 300-550° C.
5 . The method of claim 4 , further comprising providing a direct current (DC) bias to the pedestal while the upper layer of the stack of mandrel film layers is implanted.
6 . The method of claim 1 , wherein implanting the upper layer of the stack of mandrel film layers comprises delivering ions into the upper layer at an implant energy less than 10 KV.
7 . The method of claim 1 , wherein the upper layer of the stack of mandrel film layers is a spin-on-carbon layer.
8 . The method of claim 1 , wherein the mask film layer is a high-stress dielectric layer.
9 . A method for patterning a stack of mandrel film layers, the method comprising:
implanting an upper layer of the stack of mandrel film layers, wherein the implant is performed at an implant energy less than 10 KV;
forming a mask film layer over the upper layer following the implant to the upper layer of the stack of mandrel film layers;
forming a patterning layer over the mask film layer;
partially removing the patterning layer and the mask film layer; and
patterning the stack of mandrel film layers to form a set of vertical features.
10 . The method of claim 9 , wherein implanting the upper layer of the stack of mandrel film layers comprises delivering ions into the upper layer while the stack of mandrel film layers is maintained at a temperature between 15-25° C.
11 . The method of claim 10 , further comprising positioning the stack of mandrel film layers atop a pedestal, wherein the pedestal is maintained at a temperature between than 300-550° C.
12 . The method of claim 11 , further comprising providing a direct current (DC) bias to the pedestal during the implanting.
13 . The method of claim 9 , wherein the upper layer of the stack of mandrel film layers is a spin-on-carbon layer, wherein the mask film layer is a high-stress dielectric layer, and wherein the patterning layer is a photoresist layer.
14 . The method of claim 9 , wherein patterning the stack of mandrel film layers to form the set of vertical features comprises:
removing the patterning layer and the mask film layer to form a mandrel;
forming a spacer over the mandrel;
partially removing the spacer; and
removing the mandrel.
15 . A method for patterning a dynamic random-access memory (DRAM) hard mask, the method comprising:
implanting an upper layer of a stack of mandrel film layers, wherein the implant is performed at an implant energy less than 10 KV;
forming a mask film layer over the upper layer following the implant to the upper layer of the stack of mandrel film layers;
forming a patterning layer over the mask film layer;
partially removing the patterning layer and the mask film layer; and
patterning the stack of mandrel film layers to form a set of buried word lines.
16 . The method of claim 15 , wherein implanting the upper layer of the stack of mandrel film layers comprises delivering ions into the upper layer while the stack of mandrel film layers is maintained at a temperature between 15-25° C.
17 . The method of claim 15 , further comprising positioning the stack of mandrel film layers atop a pedestal, wherein the pedestal is maintained at a temperature between than 300-550° C.
18 . The method of claim 17 , further comprising providing a direct current (DC) bias to the pedestal during the implanting.
19 . The method of claim 15 , wherein the upper layer of the stack of mandrel film layers is a spin-on-carbon layer, wherein the mask film layer is a high-stress dielectric layer, and wherein the patterning layer is a photoresist layer.
20 . The method of claim 15 , wherein patterning the stack of mandrel film layers to form the set of buried word lines comprises:
removing the patterning layer and the mask film layer to form a mandrel;
forming a spacer over the mandrel;
partially removing the spacer;
removing the mandrel; and
etching the stack of mandrel film layers.