Semiconductor device fabrication method using a deposition apparatus with a contoured wafer carrier ring

A method, comprising:

• placing a wafer on a step of a carrier ring in a first vacuum enclosure, wherein a backside surface of the wafer contacts the step;
• depositing a film on an exposed portion of the backside surface of the wafer while the backside surface of the wafer is in contact with the step;
• and
• depositing a semiconductor device on a front side of the wafer which is opposite to the backside surface of the wafer,
• wherein:
• the carrier ring comprises a bottom surface surrounding an opening in the carrier ring, an upper top surface, a lower top surface of the step, and an inner surface which connects the upper top surface and the lower top surface, and which is inclined outward at a non-zero taper angle relative to the vertical direction which perpendicular to the lower top surface of the step;
• the bottom surface comprises an annular bottom surface having a circular bottom inner periphery;
• the upper top surface has an upper outer periphery and closed upper inner periphery;
• the lower top surface is vertically offset downward relative to the upper top surface and comprises a circular lower inner periphery that defines the opening in the carrier ring and comprising a closed lower outer periphery;
• the inner sidewall comprises a contoured inner sidewall that connects the closed upper inner periphery and the closed lower outer periphery and comprises at least one edge at which a respective pair of inner sidewall segments are adjoined to each other at a respective angle that is greater than or less than 180 degrees;
• the upper outer periphery of the upper top surface of the carrier ring has a non-circular shape;
• the contoured inner sidewall comprises first inner sidewall surface segments, second inner sidewall surface segments, and vertical surface segments;
• the first inner sidewall surface segments have a respective arc-shaped top periphery located at a distance of a first radius from a vertical axis passing through a geometrical center of the carrier ring;
• and
• the second inner sidewall surface segments have a respective arc-shaped top periphery located at a distance of a second radius from the vertical axis;
• and
• the second radius is greater than the first radius.