Methods for stabilization of self-assembled monolayers (SAMs) using sequentially pulsed initiated chemical vapor deposition (spiCVD)
The present disclosure provides embodiments of processes and methods for stabilizing self-assembled monolayers (SAMs). In the present disclosure, a cyclic vapor deposition process is used to selectively deposit a polymer thin film on a SAM structure formed on a target material. The polymer thin film selectively deposited on the SAM structure stabilizes the SAM structure by: (a) healing defects in the SAM structure and providing blanket coverage over the target material surface, (b) preventing migration of SAM-forming molecules to neighboring non-target surfaces, and (c) increasing the thickness and rigidity of the SAM structure. In one embodiment, sequentially pulsed initiated chemical vapor deposition (spiCVD) is used to selectively deposit the polymer thin film on the SAM structure.
1. A method to stabilize a self-assembled monolayer (SAM) structure, the method comprising:
providing a substrate having a target material and a non-target material exposed on a surface of the substrate;
forming a SAM structure on a surface of the target material;
exposing the surface of the substrate to a vapor-phase precursor, which selectively condenses on the SAM structure to form a condensate layer on the SAM structure; and
subsequently exposing the surface of the substrate to a vapor-phase initiator after the condensate layer is selectively formed on the SAM structure, wherein the vapor-phase initiator reacts with and polymerizes the condensate layer to form a polymer film on the SAM structure.
2. The method of claim 1 , wherein the polymer film stabilizes the SAM structure by: (a) healing defects in the SAM structure and providing blanket coverage over the target material, (b) preventing migration of SAM-forming molecules to neighboring non-target material surfaces, and (c) increasing a thickness and rigidity of the SAM structure.
3. The method of claim 1 , wherein said exposing the surface of the substrate to the vapor-phase precursor and said subsequently exposing the surface of the substrate to the vapor-phase initiator are performed using a sequentially pulsed initiated chemical vapor deposition (spiCVD) process.
4. The method of claim 1 , wherein the surface of the substrate is initially exposed to the vapor-phase precursor for a precursor exposure time before the surface of the substrate is subsequently exposed to the vapor-phase initiator.
5. The method of claim 4 , further comprising repeating said exposing the surface of the substrate to the vapor-phase precursor and said subsequently exposing the surface of the substrate to the vapor-phase initiator for a predetermined number of cycles to selectively deposit a predetermined thickness of the polymer film on the SAM structure without contaminating the non-target material with polymer.
6. The method of claim 5 , further comprising controlling an amount of the polymer film that is selectively deposited on the SAM structure, per cycle, by varying at least one of the precursor exposure time and a vapor pressure of the vapor-phase precursor.
7. The method of claim 5 , wherein prior to exposing the surface of the substrate to the vapor-phase precursor, the method further comprises:
determining a selectivity window based on polymer growth rates achieved per cycle on the SAM structure and on the non-target material; and
selecting, from within the selectivity window, the predetermined number of cycles needed to selectively deposit the predetermined thickness of the polymer film on the SAM structure without contaminating the non-target material with polymer.
8. The method of claim 1 , wherein said providing the substrate comprises providing the substrate within a processing tool, and wherein said forming the SAM structure, said exposing the surface of the substrate to the vapor-phase precursor and said subsequently exposing the surface of the substrate to the vapor-phase initiator are each performed within the processing tool.
9. The method of claim 1 , wherein the vapor-phase precursor is a monomer precursor selected from a group consisting of glycidyl methacrylate (GMA), alkyl acrylates, alkyl cyclosiloxane, trivinyltrimethoxycyclotrisiloxane, and perfluoroalkylethylmehacrylate, and wherein the vapor-phase initiator is selected from a group consisting of tert-butylperoxide (TBPO), perfluorooctane sulfonyl fluoride, triethylamine, and organic peroxides.
10. The method of claim 1 , wherein the vapor-phase precursor is glycidyl methacrylate (GMA), and wherein the vapor-phase initiator is tert-butylperoxide (TBPO).
11. The method of claim 1 , wherein said forming the SAM structure on the surface of the target material comprises forming the SAM structure on a metal material, a hard mask material or a photoresist material.
12. A method to stabilize a self-assembled monolayer (SAM) structure utilized in a dielectric-on-dielectric process, the method comprising:
providing a substrate having a patterned dielectric layer and a patterned metal layer exposed on a surface of the substrate;
forming a SAM structure on a surface of the patterned metal layer;
sequentially exposing the surface of the substrate to a vapor-phase monomer precursor followed by a vapor-phase initiator, wherein the vapor-phase monomer precursor selectively condenses within the SAM structure to form a monomer condensate layer within the SAM structure, and wherein the vapor-phase initiator reacts with and polymerizes the monomer condensate layer to form a polymer film that is interdigitated with the SAM structure; and
repeating said sequentially exposing the surface of the substrate to the vapor-phase monomer precursor followed by the vapor-phase initiator for a predetermined number of cycles to selectively deposit a predetermined thickness of the polymer film within and on top of the SAM structure without contaminating the patterned dielectric layer with polymer.
13. The method of claim 12 , wherein said sequentially exposing the surface of the substrate to the vapor-phase monomer precursor followed by the vapor-phase initiator is performed using a sequentially pulsed initiated chemical vapor deposition (spiCVD) process.
14. The method of claim 12 , wherein said sequentially exposing the surface of the substrate to the vapor-phase monomer precursor followed by the vapor-phase initiator comprises initially exposing the surface of the substrate to the vapor-phase monomer precursor for a precursor exposure time before the surface of the substrate is subsequently exposed to the vapor-phase initiator.
15. The method of claim 14 , further comprising controlling an amount of the polymer film that is selectively deposited on the SAM structure, per cycle, by varying at least one of the precursor exposure time and a vapor pressure of the vapor-phase monomer precursor.
16. The method of claim 12 , wherein prior to said sequentially exposing the surface of the substrate to the vapor-phase monomer precursor followed by the vapor-phase initiator, the method further comprises:
determining a selectivity window based on polymer growth rates achieved per cycle on the SAM structure and on the patterned dielectric layer; and
selecting, from within the selectivity window, the predetermined number of cycles needed to selectively deposit the predetermined thickness of the polymer film within and on top of the SAM structure without contaminating the patterned dielectric layer with polymer.
17. The method of claim 12 , wherein after the predetermined thickness of the polymer film is selectively deposited within and on top of the SAM structure, the method further comprises depositing a dielectric material on a surface of the patterned dielectric layer.
18. The method of claim 17 , wherein said depositing the dielectric material comprises exposing the surface of the substrate to a dielectric precursor, which reacts with and bonds to the surface of the patterned dielectric layer to deposit the dielectric material on the surface of the patterned dielectric layer.
19. The method of claim 17 , wherein the polymer film stabilizes the SAM structure by: (a) healing defects in the SAM structure and providing blanket coverage over the patterned metal layer, (b) preventing migration of SAM-forming molecules to the dielectric material deposited on the surface of the patterned dielectric layer, and (c) increasing a thickness and rigidity of the SAM structure to direct vertical growth of the dielectric material and prevent mushrooming of the dielectric material over the patterned metal layer.
20. The method of claim 17 , wherein said providing the substrate comprises providing the substrate within a processing tool, and wherein said forming the SAM structure, said sequentially exposing the surface of the substrate to the vapor-phase monomer precursor followed by the vapor-phase initiator and said depositing the dielectric material on the surface of the patterned dielectric layer are each performed within the processing tool.