Taiwan Semiconductor Manufacturing Comp. Ltd.

Bao Ru Yang

Sen Fu Chen

Wen Cheng Chang

Wen-Chuan Chiang

Po-Tau Chu

James Jann-Ming Wu

Heng Hsin Liu

The poor uniformity of Interlevel Dielectric Deposition (ILD) thickness for High Aspect Ratio (HAR) contact after Chemical Mechanical Planarization (CMP) will cause serious underlayer loss due to the longer over-etching time that is required to compensate for thickness differences within the wafer. Prior Art uses 1.5K Plasma Enhanced Tetra-Ethyl-Ortho-Silicate (PETEOS) to serve as a stop layer and thus reduce underlayer loss. The present invention teaches using a non-silicon oxide containing SiN/SiON or Si,N,/SiON as a stop layer. The present invention therefore is aimed at reducing underlayer loss and thereby improving the uniformity of the underlayer thickness upon completion of the hole etching process. Concurrently, the over-etch time can be reduced to less than 10% of the time required for Prior Art contact hole etching.

Uniformity improvement of high aspect ratio contact by stop layer

A patterned silicon nitride layer formed over a semiconductor integrated circuit wafer having a layer of pad oxide is often used as a mask for subsequent processing steps. Etching of the silicon nitride layer is difficult to control and can create defects in the pad oxide layer which are difficult to detect before the manufacture of the semiconductor integrated circuit wafer is completed. A method is described using potassium hydroxide treatment and scanning electron microscope evaluation of a test wafer for detection of defects at the silicon nitride etching step. Continued processing of defective wafers can be terminated and the silicon nitride etching step can be controlled using this method.

Method of monitoring and controlling a silicon nitride etch step

A method for forming damage free patterned layers adjoining the edges of high step height apertures within integrated circuits. There is first provided a semiconductor substrate which has a first aperture formed therein. Formed upon the semiconductor substrate and into the first aperture is a blanket layer. The blanket layer has a second aperture formed therein where the blanket layer is formed into the first aperture. Formed then into the second aperture is a buffer layer. The buffer layer substantially planarizes the blanket layer. Formed then upon the semiconductor substrate is a blanket photoresist layer. The blanket photoresist layer and the blanket layer are then sequentially patterned to form a patterned photoresist layer and a damage free patterned layer.

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I Lan, Taiwan

Bao Ru Yang