System and method for aligning substrates for multiple implants

An apparatus for implanting workpieces comprising:

• an ion implanter for implanting ions into a substrate to create an implanted feature, wherein the implanted feature is optically visible prior to a thermal annealing and is not optically visible subsequent to the thermal annealing;
• a fiducial marking device for applying a fiducial to the substrate, wherein the fiducial marking device is configured to apply a fiducial that remains optically visible subsequent to the thermal annealing;
• a detector for detecting the location of the fiducial on the substrate;
• a processor executing instructions for:
• determining the location of the fiducial;
• adjusting a position of a mask to align with the fiducial to thereby align the mask;
• and
• implanting ions through the mask into the substrate using the ion implanter.

A method of processing a substrate, comprising:

• implanting ions into a substrate to create an optically visible implanted feature;
• thermal annealing the substrate, wherein the thermal annealing renders the implanted feature not optically visible, wherein a fiducial on the substrate is optically visible subsequent to the thermal annealing;
• adjusting a position of a mask to align with a fiducial to thereby align the mask with the implanted feature;
• and
• implanting ions through the mask into the substrate.