Taiwan Semiconductor Manufacturing Comp. Ltd.

Yun-Chen Lu

Chung-Chi Ko

Hui-Lin Chang

Tien I Bao

A method of lowering the dielectric constant of an organosilicon low k dielectric layer while improving the hardness and thermal stability is provided. A deposited layer of carbon doped oxide, HSQ, or MSQ is cured and treated with a He plasma which improves hardness for a subsequent CMP step and lowers the dielectric constant. There is no loss of HO or CHduring the He treatment. The low k dielectric layer is then treated with a Hplasma which converts some of the Si&#x2014;O and Si&#x2014;CHbonds near the surface to Si&#x2014;H bonds, thereby further lowering the dielectric constant and increasing thermal stability that improves breakdown resistance. Moisture uptake is also reduced. The method is especially useful for interconnect schemes with deep sub-micron ground rules. Surprisingly, the k value obtained from two different plasma treatments is lower than when two He treatments or two Htreatment are performed.

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Taipei, Taiwan

Yun-Chen Lu