Analysis of Al and Cu salt infiltration into a poly 2-vinylpyridine (P2vP) polymer layer for area selective deposition applications

Abstract

This work is motivated by the desire to develop a semiconductor device patterning technology based on precursor infiltration into block copolymer materials. Developing an understanding of the preferential infiltration of metal precursors into one of the polymer blocks is of critical importance to advance this patterning approach. In this study, metal salts were used as a means to diffuse metal ions into a poly 2-vinylpyridine (P2vP) polymer brush layer (~4 nm thick) which was deposited by spin coating on a silicon substrate. Thin P2vP films infused with aluminum nitrate and copper nitrate by a wet chemical process were analyzed with angle resolved hard x-ray photoelectron spectroscopy (AR HAXPES). From these photoemission measurements, significant information about the chemical compositional profile of the infiltrated films was obtained. The large sampling depth of HAXPES measurements (20–30 nm) enabled details of the chemical composition of the thin film to be characterized and subsequent angle-resolved HAXPES measurements offered a robust analysis of the interfaces and discrete layers that are present in the films. These measurements displayed evidence of bonding interactions between the elements in the polymer film and the infiltrated salts assisting in the development of an understanding of the infiltration process which needs to be optimized for device fabrication applications. Aluminum nitrate presented more evidence of infiltration into P2vP, while copper nitrate was more predominated at the surfaces into the P2vP.

Aluminium oxide formation via atomic layer deposition using a polymer brush mediated selective infiltration approach

“…P2VP can undergo chemical coordination with metal species, facilitated by the electron lone pair in the polymer's pyridinic N [35][36][37]. It is believed that the Al exists in a complex multi -oxidised state at this stage which includes Al -pyridinyl nitrogen bonding [38]. This type of metalpyridine bonding has been observed for the P2VP-OH brush films that have been infiltrated with Cu through a liquid phase infiltration process [13].…”

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO2 Thin Films by Vapor-Phase Infiltration

“…The brush was selectively grafted using end groups that bind to site-specific wafer regions. Further, we demonstrated a simple approach for rapid grafting (in seconds) of end functionalized reactive polymer brush films with complete coverage and subsequent conversion to various oxides (Al2O3 55 , Co3O4 56 , CuO 57,58 ) via liquid phase metal ion insertion. Surface deactivation was also achieved using a PS-OH brush that prevents the deposition of ions.…”

“…Our previous work demonstrated the feasibility of covalently grafting polymer brush films to selectively deactivate the patterned Cu/SiO 2 line space for ASD of metal layers. 53 We demonstrated rapid grafting of reactive polymer brush films and subsequent conversion to various oxides (Al 2 O 3 , 54 Co 3 O 4 , 55 and CuO 56,57 ) via liquid-phase metal-ion insertion. Liquid-phase deposition of metal ions on grafted brushes has many benefits because of the multitude of readily available, low-cost, and easily prepared (water-soluble) salt precursors.…”

Analysing trimethylaluminum infiltration into polymer brushes using a scalable area selective vapor phase process

“…Mani-Gonzalez et al and others. 50,[61][62][63] Peak (ii) is unique in that it occurs in the pre VPI pyridines as well. This peak has been assigned previously as pyrrolic nitrogen (C-NH-C).…”