The 7 nm manufacturing process will be superseded by the 5 nm one by 2020. Right now, TSMC is working to improve the extreme ultraviolet lithography tech that should lead to reduced power consumption and considerable performance gains for the 7+ nm chips in late 2018. TSMC estimates that the performance gains and power requirements will see minor improvements with the 5 nm stepping.
https://www.notebookcheck.net/TSMC-reveals-more-details-on-the-5-nm-manufacturing-process.302988.0.html