Abstract: Strip-shaped alignment marks 14 are juxtaposed with each other in a silicon oxide film 12 formed on a silicon wafer 10. Each alignment mark 14 comprises a plurality of grooves 16 formed side by side in the silicon oxide film 12. An amorphous silicon film 18 is buried in the grooves 16. Thus, the alignment marks 14 are formed in a thus-formed line-and-space pattern. Accordingly, waveforms of detected signals having high contrast and little deformation can be obtained, and alignment of wafers with high accuracy can be realized.

Abstract: Strip-shaped alignment marks 14 are juxtaposed with each other in a silicon oxide film 12 formed on a silicon wafer 10. Each alignment mark 14 comprises a plurality of grooves 16 formed side by side in the silicon oxide film 12. An amorphous silicon film 18 is buried in the grooves 16. Thus, the alignment marks 14 are formed in a thus-formed line-and-space pattern. Accordingly, waveforms of detected signals having high contrast and little deformation can be obtained, and alignment of wafers with high accuracy can be realized.

Abstract: A modified LOCOS isolation process for semiconductor devices is disclosed. First, a shielding layer is formed overlying a semiconductor substrate. The shielding layer is then patterned to form an opening that exposes a portion of the semiconductor substrate for forming a device isolation region. Next, oxygen ions are implanted with a tilt angle into the semiconductor substrate to form a doped region extending to the area under the margin of the shielding layer. A thermal oxidation process is then performed to form a field oxide layer on the semiconductor substrate. Since the oxidation rate of the area under the margin of the shielding layer is increased by the implanted oxygen ions, the bird's beak effect shown in conventional LOCOS process can be eliminated. After that, the shielding layer is removed to complete the fabricating process of this invention.