Side Wall Of Teos-sio <sub> 2 </ Sub> Thin-layer Removal And Re-deposition,

In the fabrication of integrated circuits(IC), the transistor is basic device, and its self-aligned structure and process formation technology of gate and source/drain is the key part of IC manufacturing. In the deep sub-micron IC technology, Lightly Doped Drain (LDD) structure is commonly used to improve the MOS transistor performance. The gate spacer is the key feature to form the transistor with LDD structure. IC fabrication requires precise and well controlled manufacturing process. It is composed of hundreds and even thousands of processing steps. The yield depends on the quality of every process including the gate spacer formation process. How to improve the product yield will has a large influence to the economic benefits, so we focus on the spacer TEOS process to research as a project.The spacer process composed of three layers "SiO₂-SiN-SiO₂" in the 0.18um logic product technology, and the third layer of spacer is the thickest and the easiest to suffer dust particle. When the third layer of spacer suffered a certain amount of the dust particles, and the affected chip reached a certain percentage, the entire wafer have to be scrapped, it's a cost loss to the company. This article is mainly focus on the spacer TEOS₂. In the detail implementation, we have to use acid to etch off the third layer of spacer-TE0S2, then we'll measure the thickness of spacer nitride and liner-TE0S2, and measure the dust particles after removal of the spacer-TE0S2, If the dust particles won't be detected after re-deposition spacer-TE0S2, we will release wafer to the next process step. The WAT (Wafer Acceptance Test) data showed that the wafers with reprocessed spacer has similar yield as normal wafers.With the successful spacer re-processing experiment, the process will not only be applied to the dust particles by the need to scrap wafer, it can also be applied to those who have a smaller number of dust particles but do not meet the standard wafer scrapped, to improve the process and product yields.