Patent ID: 11961857
Assignee: SONY SEMICONDUCTOR SOLUTIONS CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. A manufacturing method implemented in a manufacturing apparatus that manufactures an imaging element, the manufacturing method comprising:
manufacturing a vertical transistor having a potential with a gradient in at least part of a charge transfer channel for transferring electric charge of a photoelectric conversion unit by:
forming a groove by etching a semiconductor substrate;
implanting a conductive impurity into the groove;
forming a gate insulating film in the groove, the gate insulating film having a thickness corresponding to a hierarchical level in the groove;
removing the gate insulating film until reaching a depth corresponding to the hierarchical level; and
forming a gate electrode in a groove formed in the gate insulating film,

wherein a final thickness of the gate insulating film varies in a stepwise fashion in a direction toward a transfer destination of the electric charge and is formed by repeating the formation of the gate insulating film and the removal of the gate insulating film.