Method for substrate preservation during transistor fabrication

摘要

Silicon loss prevention in a substrate during transistor device element manufacture is achieved by limiting a number of photoresist mask and chemical oxide layer stripping opportunities during the fabrication process. This can be achieved through the use of a protective layer that remains on the substrate during formation and stripping of photoresist masks used in identifying the implant areas into the substrate. In addition, undesirable reworking steps due to photoresist mask misalignment are eliminated or otherwise have no effect on consuming silicon from the substrate during fabrication of device elements. In this manner, device elements with the same operating characteristics and performance can be consistently made from lot to lot.

主权项

1. A method for fabricating a structure comprising a portion of a plurality of semiconductor devices, the method comprising:
providing a substrate having thereon a substantially flat surface comprising crystalline silicon having thereon at least one set of doped wells; providing a first protective layer on the substrate through which ion implantation steps are to be performed, the first protective layer comprising chemical oxide; isolating a first exposed area of a substrate using a first mask with the first protective layer directly over the first exposed area; implanting common dopants amenable for forming first device type elements through the first protective layer in the first exposed area; removing the first mask and the first protective layer from the substrate, removal of the first mask and the first protective layer causing a loss of silicon in the substrate; forming a second protective layer directly on the substrate through which ion implantation steps are to be performed; isolating a second exposed area using a second mask; implanting common dopants amenable for forming second device type elements through the second protective layer in the second exposed area; removing the second mask while minimizing removal of the second protective layer; removing the second protective layer.