Method for reducing line-end space in integrated circuit patterning

A method, comprising:

• forming a resist pattern over a structure, the resist pattern having a trench surrounded by first resist walls extending lengthwise along a first direction and second resist walls extending lengthwise along a second direction perpendicular to the first direction, wherein the trench is longer along the first direction than along the second direction;
• loading the structure and the resist pattern into an ion implanter so that a top surface of the resist pattern faces an ion travel direction of the ion implanter;
• tilting the structure and the resist pattern so that the ion travel direction forms a tilt angle with respect to an axis perpendicular to the top surface of the resist pattern;
• first rotating the structure and the resist pattern around the axis to an initial position so that the ion travel direction is in a plane containing the first direction and the axis;
• after the first rotating, second rotating the structure and the resist pattern around the axis to multiple ion implantation positions;
• and
• implanting ions into the first and second resist walls at the multiple ion implantation positions, wherein the implanting of the ions reduces a dimension of the second resist walls in the first direction by a first amount, and reduces a dimension of the first resist walls in the second direction by a second amount, wherein the first amount is greater than the second amount.

A method, comprising:

• forming a resist pattern over a structure, the resist pattern having a trench surrounded by first resist walls extending lengthwise along a first direction and second resist walls extending lengthwise along a second direction perpendicular to the first direction, wherein the trench is longer along the first direction than along the second direction;
• loading the structure and the resist pattern into an ion implanter so that a top surface of the resist pattern faces an ion travel direction of the ion implanter;
• tilting the structure and the resist pattern so that the ion travel direction forms a tilt angle of at least 40 degrees with respect to with respect to an axis perpendicular to the top surface of the resist pattern;
• implanting ions into the first and second resist walls using the ion implanter, wherein the implanting of the ions reduces a dimension of the second resist walls in the first direction at a first rate, and reduces a dimension of the first resist walls in the second direction at a second rate, and the first rate is greater than the second rate, thereby forming a modified trench in the resist pattern;
• transferring the modified trench in the resist pattern into a dielectric layer of the structure, thereby forming a dielectric trench;
• and
• filling the dielectric trench with a metal material.