Patent ID: 11901395
Assignee: COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 4:
5. Method of forming an insulation structure inside and on top of a first semiconductor substrate, comprising the steps of:
a) forming a trench vertically extending in the first substrate from a first surface of the first substrate;
b) filling the trench, from the first surface of the first substrate, with a polysilicon region;
c) thinning the first substrate on the side of a second surface of the first substrate, opposite to the first surface, to expose the polysilicon region at the bottom of the trench;
d) removing the polysilicon region from the second surface of the first substrate; and
e) filling the trench, from the second surface of the first substrate, with a metal, the method further comprising, between step b) and step c), a step where:
the polysilicon region is removed from across a portion of the depth of the trench;
a second electrically-insulating layer is formed on a free upper surface of the poly silicon region; and
the filling of the trench is completed.