Taiwan Semiconductor Manufacturing Comp. Ltd.

Ying-Ying Wang

Yung-Yao Lee

Chia-Shiung Tsai

Heng-Hsin Liu

Yi-Ping Hsieh

Bao-Ju Young

Hun-Jan Tao

Huan-Just Lin

Hung-Chang Hsieh

Chu-Yun Fu

Fang-Cheng Chen

Shang-Wern Chang

One embodiment relates to a method for overlay sampling. The method provides a number of fields over a semiconductor wafer surface. An inner subgroup of the number of fields includes fields in a central region of the wafer surface. An outer subgroup of the number of fields includes neighboring fields near a circumferential edge of the wafer surface. The method measures a first number of overlay conditions at a corresponding first number of overlay structures within a field of the inner subgroup. The method also measures a second number of overlay conditions at a corresponding second number of overlay structures within a field of the outer subgroup. The second number is greater than the first number. Based on the measured first number of overlay conditions and the measured second number of overlay conditions, the method determines an alignment condition for two or more layers on the semiconductor wafer surface.

Overlay sampling methodology

An edge-dominant alignment method for use in an exposure scanner system is provided. The method includes the steps of: providing a wafer having a plurality of shot areas, wherein each shot area has a plurality of alignment marks; determining a first outer zone of the wafer, wherein the first outer zone includes a first portion of the shot areas along a first outer edge of the wafer; determining a scan path according to the shot areas of the first outer zone; and performing an aligning process to each shot area of the first outer zone according to the scan path and an alignment mark of each shot area of the first outer zone.

Edge-dominant alignment method in exposure scanner system

The present disclosure provides an overlay metrology method, an overlay control method and an overlay control system. The overlay metrology method includes capturing a current layer image of a current overlay mark on a current layer with a current focal length and capturing a previous layer image of a previous overlay mark on a previous layer with a previous focal length. Then, the overlay metrology method further includes combining the current layer image with the previous layer image to form an overlay mark image and determining an overlay error between the current overlay mark and the previous overlay mark based on the overlay mark image.

Overlay metrology method and overlay control method and system

A process of measuring overlay metrologies of wafers, the wafer having a plurality of patterned layers. The process begins with retrieving historical overlay metrologies from a database, and real overlay metrologies of a first group of the wafers are measured. On the other hand, virtual overlay metrologies of a second group of the wafers are calculated with the retrieved historical overly metrologies. The real overlay metrologies of the first group of the wafers and the virtual overlay metrologies of the second group of the wafers are stored to the database as the historical overlay metrologies.

Overlay metrology method

A new method of forming a bi-layer photoresist mask with a reduced critical dimension bias between isolated and dense lines and reduced edge roughness is described. A layer to be etched is provided on a semiconductor substrate wherein the surface of the layer has an uneven topography. The layer to be etched is coated with a first planarized photoresist layer which is baked. The first photoresist layer is coated with a second silicon-containing photoresist layer which is baked. Portions of the second photoresist layer not covered by a mask are exposed to actinic light. The exposed portions of the second photoresist layer are developed away. Then, portions of the first photoresist layer not covered by the second photoresist layer remaining are developed away in a dry development step wherein sufficient SO gas is included in the developing recipe to reduce microloading to form a bi-layer photoresist mask comprising the first and second photoresist layers remaining. Thereafter, the bi-layer photoresist mask is ashed to smooth its sidewall edges. This completes formation of a bi-layer photoresist mask having a reduced critical dimension bias between isolated and dense lines and reduced edge roughness.

Dry development process for a bi-layer resist system

A new method of forming a bi-layer photoresist mask with a reduced critical dimension bias between isolated and dense lines and reduced edge roughness is described. A layer to be etched is provided on a semiconductor substrate wherein the surface of the layer has an uneven topography. The layer to be etched is coated with a first planarized photoresist layer which is baked. The first photoresist layer is coated with a second silicon-containing photoresist layer which is baked. Portions of the second photoresist layer not covered by a mask are exposed to actinic light. The exposed portions of the second photoresist layer are developed away. Then, portions of the first photoresist layer not covered by the second photoresist layer remaining are developed away in a dry development step wherein sufficient SO,gas is included in the developing recipe to reduce microloading to form a bi-layer photoresist mask comprising the first and second photoresist layers remaining. Thereafter, the bi-layer photoresist mask is ashed to smooth its sidewall edges. This completes formation of a bi-layer photoresist mask having a reduced critical dimension bias between isolated and dense lines and reduced edge roughness.

Dry development process for a bi-layer resist system utilized to reduce microloading

A process is described for forming very narrow polysilicon gate lines for use as gate electrodes in FETs. The process uses a consumable hard mask of silicon oxynitride covered by a thin layer of silicon oxide during the etching of the polysilicon. The thicknesses of the two layers that make up the hard mask are chosen so that the structure also serves as an ARC for the photoresist coating immediately above it. A relatively thin layer of the latter is used in order to improve resolution. After the photoresist has been patterned it may be trimmed or it may be removed and re-formed, since the silicon oxide layer provides protection for the underlying silicon oxynitride. After the hard mask has been formed, all photoresist is removed and the polysilicon is etched. During etching there is simultaneous removal of the silicon oxide layer and part of the silicon oxynitride as well.

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Xin-Zhu, Taiwan

Ying-Ying Wang