The first part is the Atom X3, which is expected in Q1 2016. It's designed for entry-level tablets and the chip itself is manufactured on the 28nm process.
The Atom X5 and Atom X7 are expected in the second quarter, these chips are made on the 14nm process and are intended for mainstream and high-end tablets, respectively.
In the fourth quarter of 2016, the chip giant will follow up with the Core m5/m7, these 14nm chips are intended for deluxe tablets.
Source: DigiTimes