Patent ID: 11961706
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 16:
17. A method, comprising:
placing a wafer onto a rotating fixture within a process chamber of an etching system, wherein the wafer has a tilted angle 0 and a rotated angle a;
supplying a screen grid voltage to a screen grid element of a screen grid to extract ions from plasma within a plasma chamber of the process chamber to form an ion beam;
supplying an extraction grid voltage to an extraction grid element of an extraction grid, wherein an ion current density of the ion beam depends on a voltage difference between the screen grid voltage and the extraction grid voltage;
supplying an accelerator grid voltage to an accelerator grid element of an accelerator grid, wherein an ion beam energy for the ion beam depends on a voltage difference between the extraction grid voltage and the accelerator grid voltage;
supplying a decelerator grid voltage to a decelerator grid element of a decelerator grid, wherein the screen grid element, the extraction grid element, the accelerator grid element, and the decelerator grid element form a hole that extends through the screen grid, the extraction grid, the accelerator grid, and the decelerator grid, and the ion beam goes through the hole; and
performing directional etching of a dielectric layer on the wafer by the ion beam through the hole to reach the wafer wherein performing the directional etching comprises forming, in the dielectric layer, an opening with a first length along a first direction and a second length along a second direction perpendicular to the first direction, and wherein the first and second directions are along a horizontal plane of the dielectric layer.