Patent ID: 11876094
Assignee: NANYA TECHNOLOGY CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for fabricating a semiconductor device, comprising:
providing a substrate and defining a first active region, a second active region, and a third active region; and
forming a first trench, a second trench, and a third trench in the first active region, the second active region, and the third active region of the substrate respectively, wherein the first trench, the second trench, and the third trench are indented from a top surface of the substrate;
forming a first insulating film over the first active region, the second active region, and the third active region of the substrate and in the first trench, the second trench, and the third trench;
removing the first insulating film at the first active region and the third active region of the substrate, wherein the first insulating film is remained at the second active region of the substrate and in the second trench;
forming a second insulating film over the first active region, the second active region, and the third active region of the substrate and in the first trench, the second trench, and the third trench;
removing the second insulating film at the first active region of the substrate, wherein the second insulating film is remained at the second active region and the third active region of the substrate, and in the second trench and the third trench;
forming a third insulating film over the first active region, the second active region, and the third active region of the substrate and in the first trench, the second trench, and the third trench;
forming a first conducive film over the first active region, the second active region, and the third active region of the substrate, on the third insulating film, and in the first trench, the second trench, and the third trench;
removing the first conducive film at the first active region and the second active region of the substrate, wherein the first conducive film is remained at the third active region of the substrate, and in the third trench;
forming a second conducive film over the first active region, the second active region, and the third active region of the substrate, and in the first trench, the second trench, and the third trench;
forming a filler film over the substrate and in the first trench, the second trench, and the third trench;
removing the first insulating film, the second insulating film, the third insulating film, the first conductive film, the second conductive film, and the filler film above the top surface of the substrate; and
concurrently forming a first semiconductor unit, a second semiconductor unit, and a third semiconductor unit in the first trench, the second trench, and the third trench of the substrate respectively;
wherein the first semiconductor unit comprises a first insulating stack, the second semiconductor unit comprises a second insulating stack, and the third semiconductor unit comprises a third insulating stack; and thicknesses of the first insulating stack, the second insulating stack, and the third insulating stack are all different.