Classifieds

In semiconductor manufacturing plasma asher/stripper is the process of removing the photoresist from an etched wafer. Using a plasma source, a monatomic reactive species is generated. Oxygen or fluorine are the most common reactive species. The reactive species combines with the photoresist to form ashing which is removed with a vacuum pump.

Typically, monatomic (single atom) oxygen plasma is created by exposing oxygen gas (O2) to ionizing radiation. At the same time, many free radicals are formed which could damage the wafer. Newer, smaller circuitry is increasingly susceptible to these particles. Originally, plasma was generated in the process chamber, but as the need to get rid of free radicals has increased, many machines now use a downstream plasma configuration, where plasma is formed remotely and channeled to the wafer. This allows electrically charged particles time to recombine before they reach the wafer surface, and prevents damage to the wafer surface.

Monatomic oxygen is electrically neutral and although it does recombine during the channeling, it does so at a slower rate than the positively or negatively charged free radicals, which attract one another. Effectively, this means that when all of the free radicals have recombined, there is still a portion of the active species available for process. Because a large portion of the active specie is lost to recombination, process times may take longer. To some extent, these longer process times can be mitigated by increasing the temperature of the reaction area.

Allwin21 Corp focuses on the following main Asher Stripper Descum equipments.

Matrix 105
Matrix 205
Gasonics Aura 1000
Gasonics Aura 2000
Gasonics Aura 3010
Tegal 901e
Tegal 903e
Branson IPC 3000
Branson IPC L3200

These systems can be used as descum which can increase the yield of optical lithography.
AW Control Software and Superior Temperature Control Technology provide the unique upgrade system for Matrix, Gasonics Aura, Tegal, Branson IPC Series. Advantage of upgraded system include:

Integrated process control system
Real time graphics display
Real time process data acquisition, display, and analysis
Programmed comprehensive calibration and diagnostic functions
Better performance and maintenance than the original systems

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