Glossary

Crust.

During high dose implantation using photo-resist masks, the implanted species (especially heavy ones like arsine) transfere the upper layer of the resist to pure carbon by knocking out hydrogen, this is lyer is called crust. During subsequent heat treatments (e. g. the stripping process) remaining solvent in the resist below the crust might expand and cause explosions that form particles. This phenomena is usually called popping.

Etching Rate.

The amount of material removed per unit time in an arbitrary direction from the surface, given e. g. in nm/s or $\rm\mu m$/min. Depending on the etching process the etching rate in horizontal and vertical

Interconnect.

Lithography.

Mask.

Mask

Pattern Transfer.

During the fabrication of an typical IC several different layers with different structures must be created to form the entire IC  .

Photo-resist (PR).

A organic material which is typically coated onto the surface by a spin on process. The photo-resist changes its chemical properties by exposure to light of a suitable wavelength. Depending on the material the exposed or non-exposed parts can be wet etched or developed by an appropriate solution.

Polymer.

A rather poorly defined term, very widely used in plasma etching to denote something not perfectly known, deposited from the plasma to protect sidewalls, achieve high selectivity or to the other side, form films on the chamber creating particles. In general a polymer is a chain formed from smaller molecules, in plasma etching polymers consist mainly from some coumpounds out of the following list: carbon (from the resist mask), flourine, hydrogen, metals (redeposited from the etch process). But also Si-O-Cl or Si-Br-O compounds deposited for sidewall passivation in poly etching are called polymers. Polymers are usually difficult to remove and are a real challange for the stripping process.

Selectivity.

The ratio of the etch rates of different materials under the same process conditions. In practice this is an important issue, consider e. g. an insulating layer of silicon oxide over silicon which should be etched through without damaging or removing the substrate.

Sputtering.

Removal of material ..