Hi Didier,
i-MEMS is an ADI proprietary process of integrating sensor and electronics on the same die. We have recently moved away from that for some of our products. So today our products are a mix of integrated and discrete (sensor and electronics) dies.
Irrespective of the fabrication process used, all the relevant performance parameters (for customers) are listed in Table 1 of our datasheet.
The X and Y alignment is 0.1 deg (typical) and the Z axis tilt is +/-1deg.
regards,
Venkat