Abstract: A method of removing photoresist is provided. In the whole process of removing the photoresist, plasma is not used. Instead, a first solution is used in a first removal step to remove a photoresist layer. Then, a second solution is used in a second removal step to completely remove the photoresist layer. The first solution and the second solution have different polarities, and the polarity of the first solution is large than that of the second solution.

Abstract: A method of removing photoresist is provided. In the whole process of removing the photoresist, plasma is not used. Instead, a first solution is used in a first removal step to remove a photoresist layer. Then, a second solution is used in a second removal step to completely remove the photoresist layer. The first solution and the second solution have different polarities, and the polarity of the first solution is large than that of the second solution.

Abstract: An alignment strategy for asymmetrical alignment marks in a wafer, in which the positions of the a symmetrical alignment marks are determined twice. A first set of positions is detected after a chemical-mechanical polishing step. A second set of positions is detected after a rotation in which the wafer is rotated by 180.degree. in the plane of the surface of the wafer.

Abstract: An improved aligner detector is provided. The improved aligner detector includes, a detector, several electrooptic modulators, and a refractor set, which includes several wedge patterns. Each of the electrooptic modulators includes a double-refraction transistor, which has a property of double refraction. By applying a special voltage on the double-refraction transistors, the double-refraction transistors can become transparent or opaque. Thereby, the electrooptic modulators can select a desired order of the diffraction light ray. The selected diffraction light ray is refracted by the refractor set to the detector for analysis.

Abstract: A method for aliging a shallow trench isolation is provided. An aligning mark which is deeper than a prior technique is formed in a provided substrate. A trench is formed and an aligning trench is formed in the position over the aligning mark. A thick oxide layer is deposited on the semiconiductol substrate, in the trench and in the aligning trench. After a portion of the thick oxide layer removed, another portion of the thick oxide layer is removed by etching back. A gate oxide layer is formed on a substrate comprising the trench and the aligning trench. A polysilicon layer with the step-height profile in the position over the aligning mark is formed on the gate oxide layer.