Patent ID: 6849393

Claim:
A phase shifting lithographic process capable of creating a shrunk fine line pattern on a photoresist layer coated on a semiconductor wafer, the shrunk fine line pattern comprising a vertical fine line image and a horizontal fine line image connected to the vertical fine line image in an orthogonal manner, the phase shifting lithographic process comprising: providing a first phase shift mask comprising thereon a first phase shift clear area, a second phase shift clear area situated adjacent to the first phase shift clear area, a vertical control chrome line section disposed at a boundary between the first phase shift clear area and the second phase shift clear area, and a horizontal opaque area connected to the vertical control chrome line section in an orthogonal manner; implementing a first exposure process to expose the photoresist layer to light transmitted from clear areas of the first phase shift mask so as to form the vertical fine line image corresponding to the vertical control chrome line section disposed at a boundary between the first phase shift clear area and the second phase shift clear area, a horizontal unexposed area connected to the vertical fine line image in an orthogonal manner, and a peripheral unexposed line pattern; providing a second phase shift mask comprising thereon a third phase shift clear area, a fourth phase shift clear area situated adjacent to the third phase shift clear area, a horizontal control chrome line section disposed at a boundary between the third phase shift clear area and the fourth phase shift clear area, and a vertical opaque area connected to the horizontal control chrome line section in an orthogonal manner for shielding the vertical fine line image on the photoresist layer; and implementing a second exposure process to expose the photoresist layer to light transmitted from clear areas of the second phase shift mask so as to form the horizontal fine line image corresponding to the horizontal control chrome line section disposed at a boundary between the third phase shift clear area and the fourth phase shift clear area.