Mark position detecting method and device for aligner and aligner having the device

A mark position detecting device for an aligner which aligns between a mask and a semiconductor wafer and exposes a pattern on said mask onto said wafer, said device detecting a position of a rectangular mark formed on an object which is either said wafer or said mask, said object being positioned such that one of two sides of said rectangular mark becomes parallel to an X-direction and the other of said two sides becomes parallel to a Y-direction which is perpendicular to said X-direction, said device comprising:

• a line sensor;
• a light source for illuminating an area on said object, said area covering said rectangular mark;
• optical means for converging a reflected light onto said line sensor with respect to a cross section of said line sensor and forming said reflected light into a magnified image on said line sensor with respect to a longitudinal section of said line sensor, said reflected light being from said area, said cross section being parallel to said Y-direction, said longitudinal section being parallel to said X-direction;
• and
• signal processing means for processing an output signal from said line sensor so as to detect an X-directional representative position of said rectangular mark.

An aligner for aligning between a mask and a semiconductor wafer and for exposing a pattern on said mask onto said wafer, said aligner detecting a position of a rectangular mark formed on an object which is either said wafer or said mask, said aligner comprising:

• a movable stage on which said object is placed such that one of two sides of said rectangular mark becomes parallel to an X-direction and the other of said two sides becomes parallel to a Y-direction which is perpendicular to said X-direction;
• a line sensor;
• a light source for illuminating an area on said object, said area covering said rectangular mark;
• optical means for converging a reflected light onto said line sensor with respect to a cross section of said line sensor and forming said reflected light into a magnified image on said line sensor with respect to a longitudinal section of said line sensor, said reflected light being from said area, said cross-section being parallel to said Y-direction, said longitudinal section being parallel to said X-direction;
• signal processing means for processing an output signal from said line sensor so as to detect an X-directional representative position of said rectangular mark;
• and
• control means for controlling moving of said movable stage such that said X-directional representative position of said rectangular mark is positioned at a target position.