Methods of forming self-aligned contacts for a semiconductor device
One illustrative method disclosed herein involves forming gate structures for first and second spaced-apart transistors above a semiconducting substrate, forming an etch stop layer above the substrate and the gate structures, performing at least one angled ion implant process to implant at least one etch-inhibiting species into less than an entirety of the etch stop layer, after performing at least one angled ion implant process, forming a layer of insulating material above the etch stop layer, performing at least one first etching process to define an opening in the layer of insulating material and thereby expose a portion of the etch stop layer, performing at least one etching process on the exposed portion of the etch stop layer to define a contact opening therethrough that exposes a doped region formed in the substrate, and forming a conductive contact in the opening that is conductively coupled to the doped region.
1. A method, comprising:
forming gate structures for first and second spaced-apart transistors above a semiconducting substrate;
forming an etch stop layer above said substrate and said gate structures for said transistors;
performing at least one angled ion implant process to implant at least one etch-inhibiting species into less than an entirety of said etch stop layer, wherein performing said at least one angled ion implant process to implant said at least one etch-inhibiting species comprises performing a first ion implant process using one of carbon or fluorine and performing a second ion implant process using the other of said carbon or fluorine;
after performing said at least one angled ion implant process, forming a layer of insulating material above said etch stop layer;
performing at least one first etching process to define an opening in said layer of insulating material and thereby expose a portion of said etch stop layer;
performing a second etching process on said exposed portion of said etch stop layer to define a contact opening therethrough that exposes a doped region formed in said substrate; and
forming a conductive contact in said opening that is conductively coupled to said doped region.
2. The method of claim 1 , wherein performing said second etching process comprises performing a wet etching process or a dry plasma-based etching process.
3. The method of claim 1 , wherein said etch-inhibiting species is a polymer forming species and wherein performing said second etching process comprises performing a dry plasma-based etching process that causes formation of a polymer material proximate said at least one implant region.
4. The method of claim 1 , wherein performing said second etching process comprises performing a wet etching process that causes formation of a protective interfacial layer proximate said at least one implant region.
5. The method of claim 1 , wherein each of said first and second angled implant processes is performed at an angle such that said first transistor prevents the implantation of said at least one etch-inhibiting species into the entirety of the etch stop layer positioned proximate a side of said second transistor.
6. The method of claim 1 , wherein each of said first and second angled implant processes is performed at an angle such that a portion of said etch stop layer between said first and second transistors is not implanted with said etch-inhibiting species.
7. The method of claim 1 , wherein each of said first and second angled implant processes is performed at an angle such that portions of said etch stop layer within a vertical distance above a surface of said substrate that corresponds to approximately 30% of a gate height of one of said gate structures is not implanted with said etch-inhibiting species.
8. The method of claim 7 , wherein said vertical distance is about 40 nm or less.
9. The method of claim 1 , wherein each of said first and second angled implant processes is performed at an angle such that only portions of said etch stop layer that are positioned a vertical distance above a surface of said substrate that is greater than a distance that corresponds to approximately 30% of a gate height of one of said gate structures is implanted with said etch-inhibiting species.
10. The method of claim 1 , wherein each of said first and second angled ion implant processes is performed at an angle within the range of about 20-60 degrees relative to a vertical.
11. The method of claim 1 , wherein said gate structures are sacrificial gate structures.
12. The method of claim 1 , wherein said gate structures are final gate structures for said transistors.
13. The method of claim 1 , wherein said transistors are planar transistor devices.
14. The method of claim 1 , wherein said transistors are FinFET transistor devices.
15. A method, comprising:
forming gate structures for first and second spaced-apart transistors above a semiconducting substrate;
forming an etch stop layer above said substrate and said gate structures for said transistors;
performing at least one angled ion implant process to implant at least one polymer-forming species into less than an entirety of said etch stop layer, wherein performing said at least one angled ion implant process to implant said at least one polymer-forming species comprises performing a first ion implant process using one of carbon or fluorine and performing a second ion implant process using the other of said carbon or fluorine;
after performing said at least one angled ion implant process, forming a layer of insulating material above said etch stop layer;
performing at least one first etching process to define an opening in said layer of insulating material and thereby expose a portion of said etch stop layer;
performing at least one dry plasma-based etching process on said exposed portion of said etch stop layer to define a contact opening therethrough that exposes a doped region formed in said substrate; and
forming a conductive contact in said opening that is conductively coupled to said doped region.
16. The method of claim 15 , wherein forming said etch stop layer comprises performing a deposition process to form said etch stop layer comprised of silicon nitride or silicon dioxide.
17. The method of claim 15 , wherein the ratio of carbon to fluorine is about 1:2.
18. The method of claim 15 , wherein performing said dry plasma-based etching process on said etch stop layer comprises performing a carbon-fluorine based dry plasma etching process on said etch stop layer.
19. The method of claim 15 , wherein performing said dry plasma-based etching process comprises performing said dry plasma-based etching process using at least one of the following process gases: C 4 F 8 /CH 2 F 2 /Ar or C 5 F 8 and nitrogen.
20. The method of claim 15 , wherein each of said first and second angled implant processes is performed at an angle such that said first transistor prevents the implantation of said at least one polymer-forming species into the entirety of the etch stop layer positioned proximate a side of said second transistor.
21. The method of claim 15 , wherein each of said first and second angled implant processes is performed at an angle such that a portion of said etch stop layer between said first and second transistors is not implanted with said polymer-forming species.
22. The method of claim 15 , wherein each of said first and second angled implant processes is performed at an angle such that portions of said etch stop layer within a vertical distance above a surface of said substrate that corresponds to approximately 30% of a gate height of one of said gate structures is not implanted with said polymer-forming species.
23. The method of claim 22 , wherein said vertical distance is about 40 nm or less.
24. The method of claim 15 , wherein each of said first and second angled implant processes is performed at an angle such that only portions of said etch stop layer that are positioned a vertical distance above a surface of said substrate that is greater than a distance that corresponds to approximately 30% of a gate height of one of said gate structures is implanted with said polymer-forming species.
25. The method of claim 22 , wherein each of said first and second angled ion implant processes is performed at an angle within the range of about 20-60 degrees relative to a vertical.