System and technique for creating implanted regions using multiple tilt angles

A semiconductor processing apparatus, comprising:

• an ion source to generate ions;
• an accelerator to provide energy to the ions;
• a platen to hold a semiconductor workpiece;
• a platen orientation motor to adjust a tilt angle of the platen;
• and
• a controller;
• wherein the controller is configured to create an implanted region having rectangular concentration profile in the semiconductor workpiece, wherein the controller:
• sets an implant energy by adjusting a voltage supplied to the accelerator;
• sets a first tilt angle using the platen orientation motor;
• performs a first implant at the implant energy, a first dose and the first tilt angle, wherein a maximum concentration of ions implanted in the semiconductor workpiece by the first implant occurs at a first depth;
• sets a second tilt angle using the platen orientation motor;
• performs a second implant at the implant energy, a second dose and the second tilt angle, wherein a maximum concentration of ions implanted in the semiconductor workpiece by the second implant occurs at a second depth, less than the first depth;
• wherein the first tilt angle, the first dose, the second tilt angle, and the second dose are selected such that, after the first and second implants are performed, a concentration of implanted atoms decreases between a first depth and a second depth.

A semiconductor processing apparatus, comprising:

• an ion source to generate ions;
• an accelerator to provide energy to the ions;
• a platen to hold a semiconductor workpiece;
• a platen orientation motor to adjust a tilt angle of the platen;
• and
• a controller;
• wherein the controller is configured to create an implanted region having rectangular concentration profile in the semiconductor workpiece, wherein the controller:
• sets an implant energy by adjusting a voltage supplied to the accelerator;
• sets a first tilt angle using the platen orientation motor;
• performs a first implant at the implant energy and the first tilt angle, wherein a maximum concentration of ions implanted in the semiconductor workpiece by the first implant occurs at a first depth;
• sets a second tilt angle using the platen orientation motor;
• and
• performs a second implant at the implant energy and the second tilt angle, wherein a maximum concentration of ions implanted in the semiconductor workpiece by the second implant occurs at a second depth, less than the first depth;
• wherein the first tilt angle and the second tilt angle are selected such that a minimum concentration between the first depth and the second depth is greater than a predetermined minimum concentration, and a ratio of a maximum concentration to the minimum concentration is less than 5.