Lam Research Corporation

Chuan-Kai Lo

Francis Ko

Chok Ho

Chang-Tai Chiao

Young Tong Tsai

Lawrence Chen

Fang-Ju Lin

The present invention reveals a semiconductor dual damascene etching process, which uses a confined plasma etching chamber to integrate all dual damascene steps such as via hole etching, photoresist stripping and barrier layer removal which originally performed in various reactors as a continuous procedure in the confined plasma chamber. The confined plasma chamber including a confinement ring surrounding a wafer and an anti-etching upper electrode plate performs the steps mentioned above under clean mode. The present invention can not only reduce the time period required by the semiconductor dual damascene process but also greatly reduce the manufacturing cost.

All dual damascene oxide etch process steps in one confined plasma chamber

An etch that provides a high oxide to photoresist selectivity in a low-pressure, high-density plasma is provided. An extremely high reverse RIE lag is achieved, wherein the etching of small high-aspect ratio openings is possible, but that of large openings is not. A high-density plasma is generated so that carbon monoxide (CO) is ionized to CO so that at least 1 sccm equivalent of CO is provided. Excited CO neutrals (CO*) are also present within the plasma. Fluorocarbon and hydrofluorocarbon gases are also provided. The excited CO neutrals scavenge free fluorine, near the wafer surface and in the large openings, increasing polymer deposition on the photoresist and in the large openings thus reduce or stop etching in those regions. Concurrently, CO is not hindered by diffusion limitation and is readily accelerated deep into the small openings by an applied electric potential; hence, providing oxygen atoms near the bottom of the small openings which help to remove polymer at the etch front and eliminates the propensity for etch stop.

Ultra-high oxide to photoresist selective etch of high-aspect-ratio openings in a low-pressure, high-density plasma

Growing community of inventors

Hsinchu, Taiwan

Chuan-Kai Lo