Trench Tip Squaring in Self-Aligned Multi-Patterning Process

A self-aligned patterning method, comprising:

• forming a plurality of linear spacers over a base layer of a semiconductor device, wherein a set of adjacent linear spacers of the plurality of linear spacers define a trench, wherein a pillar is formed in the trench, and wherein the pillar comprises a plurality of recessed corner areas at an intersection between the pillar and the set of adjacent linear spacers;
• and
• performing a plasma treatment to form a film layer in the plurality of recessed corner areas and along a sidewall of the pillar, wherein the plasma treatment comprises directing ions to the plurality of linear spacers at a non-perpendicular angle relative to an upper surface of the base layer.

A plasma processing tool, comprising:

• a plasma chamber for generating plasma, wherein ions are extracted from the plasma and directed to a semiconductor device;
• and
• a main controller operatively coupled to plasma chamber, wherein the main controller is adapted to perform a plasma treatment by directing the ions to a plurality of linear spacers of the semiconductor device to form a film layer in a plurality of recessed corner areas and along a sidewall of a pillar, wherein the pillar is formed between a set of adjacent linear spacers of the plurality of linear spacers, and wherein the ions are directed to the plurality of linear spacers at a non-perpendicular angle relative to an upper surface of a base layer of the semiconductor device.