| 摘要 |
PURPOSE: To prevent a pattern projected onto a substrate as reduced in size from deteriorating in absolute dimensional accuracy by a method wherein a mark on the substrate is detected through a reducing lens in a stepper so as to correct the projected pattern for reduction ratio error. CONSTITUTION: A stepper is composed of a condenser lens 1, a reticle 2, a reduction projection lens 3, a substrate 4, and pattern detectors 5 and 6. The pattern detector 5 measures the position of a mark 9' in the window 7 of the reticle 2, the pattern detector 6 measures the position of a mark 9" in the window 8 of the reticle 2, and an amountΔL of deviation of a relative distance between the marks 9' and 9" to a relative distance L between the windows 7 and 8 is calculated. Therefore, a reduction ratio can be obtained through only the measurement of the positional deviationΔL of a mark 9 on a substrate 4 moved by a prescribed distance l through the reducing lens 3, and a space between the reducing lens 3 and the reticle 2 is finely adjusted so as to meet a formula,Δb=ΔL.b/L, whereby a reduction projection exposure system of this constitution can be corrected for a reduction ratio error.
|
