Method of manufacturing a semiconductor device and semiconductor device
View Patent ↗In a manufacturing step in which a structure of target of screening is formed on a semiconductor substrate in the middle of manufacturing process before a semiconductor device is finished, screening of potential defects of a gate insulating film is performed for each wafer at one time so that the semiconductor device is caused to appear as an initial defective product when the finished semiconductor device is subjected to an electrical characteristic test. Provided are a semiconductor device, and a method of manufacturing a semiconductor device which enables reliable screening of potential defects in a short period of time.
1. A method of manufacturing a semiconductor device, the semiconductor device having a gate insulating film and a gate electrode film on a semiconductor substrate of a wafer, the method comprising:
forming the gate insulating film on the semiconductor substrate;
forming the gate electrode film on an entire surface of the semiconductor substrate including the gate insulating film;
after forming the gate electrode film, screening the gate insulating film by applying an electric field to the gate insulating film and generating a potential difference between the gate electrode film and a back surface of the semiconductor substrate;
determining presence of a defect in the semiconductor substrate subjected to the screening based on a presence or absence of a saturation current; and
patterning the gate electrode film after determining presence of a defect the semiconductor substrate.
2. The method of manufacturing a semiconductor device according to claim 1 , further comprising, between forming the gate electrode film and screening the gate insulating film, removing the gate electrode film and the gate insulating film on the back surface of the semiconductor substrate and a peripheral portion of a front surface of the semiconductor substrate, and
wherein the removing the gate electrode film and the gate insulating film comprises setting a gate insulating film removal width from an end surface of the semiconductor substrate to an end surface of the gate insulating film to be smaller than a gate electrode film removal width from the end surface of the semiconductor substrate to an end surface of the gate electrode film.
3. The method of manufacturing a semiconductor device according to claim 1 , wherein determining presence of the defect in the semiconductor substrate comprises:
determining that the semiconductor substrate is non-defective when a current that flows between the semiconductor substrate and the gate electrode film saturates; and
determining that the semiconductor substrate is defective when the current does not saturate.
4. The method of manufacturing a semiconductor device according to claim 2 , wherein the determining presence of the defect in the semiconductor substrate comprises:
determining that the semiconductor substrate is non-defective when a current that flows between the semiconductor substrate and the gate electrode film saturates; and
determining that the semiconductor substrate is defective when the current does not saturate.
5. The method of manufacturing a semiconductor device according to claim 4 , further comprising disposing of one of a lot of wafers or a batch of wafers that has been processed at the same time with a defective wafer having the defective semiconductor substrate when a ratio of defective wafers in the batch or lot is equal to or larger than 20%.
6. The method of manufacturing a semiconductor device according to claim 4 , further comprising identifying and removing a cause of a contamination in each step through which a defective wafer having the defective semiconductor substrate has passed when a ratio of defective wafers in one of a lot of wafers or a batch of wafers is equal to or larger than a 50% ratio.