It belongs to the low-end process level.
The 55nm chip belongs to the low-end process level. The process level of the chip is basically the following process to distinguish between high, middle and low levels. Below 14 nm using euv lithography mechanism for high-end chips, 14-45 nm process stage for the mid-end level, 45 nm process above the low-end process level. So 55 nanometers is the low-end process level.