  Using a simple and cost-effective water jet process, silicon etch depth
limitations are overcome to realize a $6\,$mm deep atomic vapor cell. While the
minimum silicon feature size was limited to a $1.5\,$mm width in these first
generation vapor cells, we successfully demonstrate a two-chamber geometry by
including a $\sim$25~mm meandering channel between the alkali pill chamber and
main interrogation chamber. We evaluate the impact of the channel conductance
on the introduction of alkali vapor density during the pill activation process,
and mitigate glass damage and pill contamination near the main chamber.
Finally, we highlight the improved signal achievable in the $6\,$mm silicon
cell compared to standard $2\,$mm path length silicon vapor cells.
