Methods and apparatus for aligning a wafer in which multiple light beams are used to scan alignment marks
AssigneeSamsung Electronics Co., Ltd.
InventorDoo-Hoon Goo
Life of this patent
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Abstract
A wafer, having alignment marks formed thereon, is aligned by radiating a first light beam onto the alignment marks so as to generate a first diffracted light beam. The first diffracted light beam is sensed at a first position. A second light beam is radiated onto the alignment marks so as to generate a second diffracted light beam. The second diffracted light beam is sensed at a second position. A correction value is calculated based on a first difference between the first position and a first predetermined position and a second difference is calculated based on a second difference between the second position and a second predetermined position. The wafer is aligned based on the correction value.
Claims21
A method for aligning a wafer, comprising:
- providing a wafer having alignment marks formed thereon;
- radiating a first light beam onto the alignment marks so as to generate a first diffracted light beam;
- sensing the first diffracted light beam at a first position;
- radiating a second light beam onto the alignment marks so as to generate a second diffracted light beam;
- sensing the second diffracted light beam at a second position;
- calculating a correction value for aligning the wafer based on a first difference between the first position and a first predetermined position and a second difference between the second position and a second predetermined position;
- and
- aligning the wafer based on the correction value.
An apparatus for aligning a wafer, comprising:
- a stage that is configured to hold a wafer with alignment marks;
- a light source component that is configured to radiate a first light beam onto the alignment marks so as to generate a first diffracted light beam and to radiate a second light beam onto the alignment marks so as to generate a second diffracted light beam;
- a first sensing component that is configured to sense the first diffracted light beam at a first-position;
- a second sensing component that is configured to sense the second diffracted light beam at a second position;
- and
- a position correcting component that is configured to calculate a correction value for aligning the wafer based on a first difference between the first position and a first predetermined position and a second difference between the second position and a second predetermined position.
Dependencies are inferred from the claim text.