| 摘要 |
A projection alignment apparatus comprises a circuit mask holder (12) for securing a circuit mask (10) having a circuit pattern therein; a chuck for securing a wafer (20) in a wafer plane (22); an optical system (15) including mirrors (16); and a light source (5) for projecting light through the circuit mask to produce an image of said circuit pattern through the optical system on the wafer. A first target mask (25) has at least two first alignment patterns (26a-26i) thereon, at least one (26d, 26e) which is vertically displaced from a centre of the first target mask and at least one (26b, 26c) of which is horizontally displaced from said centre, each of the first alignment patterns having a horizontally disposed pattern (35, 45) and a vertically disposed pattern (30, 40). The first target mask is secured in said mask holder. A second target mask has at least two second alignment patterns (51a-51i) thereon, at least one (51d, 51e) which is vertically displaced from a centre of the second target mask and at least one (51b, 51c) of which is displaced from said centre, each of the second mask patterns having a horizontally disposed pattern (60, 70) and a vertically disposed pattern (55, 65). The second target mask is secured in said wafer plane The light source is arranged to project light through the first circuit mask to carry the image of the first alignment patterns through the optical system and be superimposed upon the second circuit mask. The first alignment patterns and the second alignment patterns have an aligned position where the first alignment patterns are superimposed over and aligned with the second alignment patterns. A mechanism is provided for producing relative movement between the first target mask and the second target mask to attempt to put the first alignment patterns and the second alignment patterns in the aligned position and for adjusting the mirrors of the optical system. |
