Alliance A 6 TCP 9400 PTX Polysilicon

Transformer coupled plasma (TCP) etchers are a class of inductively coupled plasma tools used for anisotropic, high-selectivity etching of thin films in semiconductor fabrication.

TCP etch systems generate a high-density plasma by applying radio-frequency power to a planar coil (transformer) located above the process chamber. The inductively coupled plasma provides a high ion density at low chamber pressure, enabling anisotropic etching with good critical dimension control.

In polysilicon etching, the TCP source produces a plasma of reactive gases such as chlorine or bromine-based chemistries. Ion bombardment directionality and chemical reactivity are balanced to achieve a vertical etch profile with high selectivity to underlying gate oxide.

Polysilicon gate etch is a critical step in complementary metal-oxide-semiconductor (CMOS) fabrication, performed after gate oxide growth and polysilicon deposition. The etch defines the transistor gate electrode dimensions and must achieve tight critical dimension uniformity across the wafer.

Downstream steps include resist strip, cleaning, and subsequent spacer or silicide formation. The etch tool is typically part of a cluster or an integrated module in advanced fabs to minimize particle contamination.

The TCP etch technology is also employed for other dielectric and conductor etch applications when configured with appropriate process chemistries, though the specific model is designated for polysilicon.