摘要 |
Method of fabricating a semiconductor device. A glass substrate such as Corning 7059 is used as a substrate. A bottom film is formed. Then, the substrate is annealed above the strain point of the glass substrate. The substrate is then slowly cooled below the strain point. Thereafter, a silicon film is formed, and a TFT is formed. The aforementioned anneal and slow cooling reduce shrinkage of the substrate created in later thermal treatment steps. This makes it easy to perform mask alignments. Furthermore, defects due to misalignment of masks are reduced, and the production yield is enhanced. In another method, a glass substrate made of Corning 7059 is also used as a substrate. The substrate is annealed above the strain point. Then, the substrate is rapidly cooled below the strain point. Thereafter, a bottom film is formed, and a TFT is fabricated. The aforementioned anneal and slow cooling reduce shrinkage of the substrate created in later thermal treatment steps. Thus, less cracks are created in the active layer of the TFT and in the bottom film. This improves the production yield. During heating of the substrate, it is held substantially horizontal to reduce warpage, distortions, and waviness of the substrate.
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