Patterned Polysilicon Test Wafers

Patterned Polycrystalline Silicon (Poly-Si) Wafers

PATTERNED POLYSILICON TEST WAFERS

Wafers with a Poly-Si film deposited on an insulating film, such as thermal oxide, and patterned into the specified geometry.

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40 nm Fine Pattern Fabrication Example

The 40 nm pattern is a fabrication example in which a line-and-space (L&S) photoresist pattern was narrowed by resist trimming, then transferred to Poly-Si using the resist as a mask.

Photoresist Trimming (Slimming): Principle and Process

In photoresist trimming, the resist is generally etched using a plasma generated from an oxygen-containing gas to reduce its line width.

In the diagrams, CD denotes line width, PR denotes photoresist, and SiO2 denotes thermal oxide.

Process cross section labeled PR, poly-Si, SiO2, and Si, with a double-headed arrow indicating the resist CD of 80 nm before slimming — An L&S photoresist pattern with a CD of 80 nm before trimming is formed on the Poly-Si film.

Process cross section labeled PR, poly-Si, SiO2, and Si, with a double-headed arrow indicating the CD of 40 nm after resist slimming — Both sidewalls of the resist are etched to reduce the CD from 80 nm to 40 nm while maintaining the pitch.

Process cross section showing pattern transfer to Poly-Si using the resist as a mask, with a double-headed arrow indicating the 40 nm line width — Using the resist with a CD of 40 nm as a mask, the same line width is transferred to Poly-Si.

Process cross section of Poly-Si after resist removal, with double-headed arrows indicating the 40 nm line width and 125 nm height — After resist removal, a Poly-Si pattern with a line width of 40 nm and a height of 125 nm remains.

Cross-Sectional and Top-View SEM Results

Side-by-side comparison of cross-sectional and top-view SEM images of fine Poly-Si lines — Left: cross section (line width 40 nm / height 125 nm); right: top view

250 nm L&S Pattern Fabrication Example

This is a fabrication example of an L&S pattern formed in a thick Poly-Si film. Doped Poly-Si can be used as electrode wiring that withstands high-temperature processing. It is also used to evaluate film coverage (step coverage) for different film materials.

Patterned Polysilicon Test Wafers

Patterned Polycrystalline Silicon (Poly-Si) Wafers

40 nm Fine Pattern Fabrication Example

Photoresist Trimming (Slimming): Principle and Process

Photoresist L&S Formation

Photoresist Trimming

Poly-Si Etching

Photoresist Removal

Cross-Sectional and Top-View SEM Results

250 nm L&S Pattern Fabrication Example

Cross-Sectional SEM Results