Semiconductor structures and manufacturing methods
View Patent ↗A semiconductor body having an alignment mark comprising a pair of sets of parallel lines disposed on the semiconductor body, the parallel lines in one of the sets being disposed orthogonal to the parallel lines in the other one of the set, the two sets of parallel lines being in an overlaying relationship. Also, a method and apparatus for detecting an alignment mark on a semiconductor body. The method and apparatus provide an alignment illumination comprising a pair of orthogonal, lines of impinging light which is scanned over the surface of the alignment mark, one of such pair of impinging light lines being orthogonal to, and laterally displaced from, the other one of such pair of impinging light lines, impinging light being reflected by the alignment lines in the surface of the semiconductor when such impinging light is over to provide a pair of laterally displaced beams of reflected light. The method includes detecting in a each one of a pair of laterally spaced detectors a corresponding one of the laterally displaced beams of reflected light.
1. Apparatus for detecting an alignment mark on a semiconductor body, such alignment mark comprising a pair of sets of parallel lines disposed on the semiconductor body, the parallel lines in one of the sets being disposed orthogonal to the parallel lines in the other one of the set, the two sets of parallel lines being in an overlaying relationship, such apparatus comprising:
an optical system for scanning an alignment illumination comprising a pair of orthogonal lines of impinging light over the surface of the alignment mark, one of such pair of impinging light lines being orthogonal to, and laterally displaced from, the other one of such pair of impinging light lines, impinging light being reflected by the alignment lines in the surface of the semiconductor when such impinging light is over to provide a pair of laterally displaced beams of reflected light; and
a pair of laterally spaced detectors, each one of the detectors being positioned to detect a corresponding one of the laterally displaced beams of reflected light.
2. The apparatus of claim 1 , wherein a first impinging light line is projected onto the wafer surface at an angle of −45° with respect to a Y axis, the Y axis orthogonal to the lower and top outer peripheral portion of the semiconductor body.
3. The apparatus of claim 2 , wherein a second impinging light line is projected onto the wafer surface at an angle of +45° angle with respect to the Y axis.
4. The apparatus of claim 3 , wherein the alignment light lines are separated laterally along the X axis by a distance W.
5. The apparatus of claim 4 , wherein the alignment marks are scanned first by the light line with +45° orientation and subsequently by the line with −45° orientation.
6. The apparatus of claim 1 , wherein the parallel lines comprise grooves having sidewalls terminating at the surface of the semiconductor body.
7. The apparatus of claim 6 , wherein the grooves have bottomed portions recessed into the surface portion of the wafer body.
8. The apparatus of claim 1 , wherein the apparatus comprises a detector arrangement.
9. The apparatus of claim 8 , wherein the arrangement comprises a pair of detector configurations.
10. The apparatus of claim 9 , wherein the configuration comprises a pair of detectors.
11. The apparatus of claim 10 , wherein a first detector configuration comprises a first detector for detecting left +45° and a second detector for detecting right +45° lines.
12. The apparatus of claim 11 , wherein a second detector configuration comprises a first detector for detecting left −45° and a second detector for detecting right −45° lines.
13. The apparatus of claim 10 , wherein the pair of detectors record one or more waveforms.
14. The apparatus of claim 13 , wherein the recorded waveforms are recorded without background noise from the other line orientation.