How High Temperature Quartz Tanks Improve Silicon Wafer Processing

The silicon wafer processing steps that include etching or cleaning of silicon wafers with aggressive chemicals require tanks that hold and control the chemical process. Quartz tanks are impervious to the acids and bases used in wet process stations, and the high-temperature tanks can include heating and re-circulating.

The two main factors that influence the etch rate are chemical concentration and temperature.

Silicon wafer processing consists of etching the wafers to produce microscopic structures and cleaning the wafers in preparation for further process steps. Hydrochloric acid, sulfuric acid, and hydrogen peroxide are the common chemicals used for etching and cleaning the wafers, and these are corrosive chemicals. Tanks made of quartz are impervious to such aggressive chemicals, and semiconductor-grade quartz that are used in the Modutek quartz tanks is exceptionally pure, reducing the possibility of contamination. Aside from high resistance to corrosion by aggressive chemicals, quartz tanks are stable at high temperatures.

Quartz tanks are highly resistant to aggressive chemicals because quartz is a crystalline material made up of silicon and oxygen atoms held tightly in the crystal lattice.

The use of high-purity flame-polished quartz in silicon wafer processing tanks ensures that there are few non-quartz substances in the crystal lattice and on the polished surface of the tanks. This leads to the significantly reduced possibility of contamination by the tanks. Contamination of the silicon wafers can affect the semiconductor products made from the wafers. When a tiny particle or other contaminant interferes with the etching of these structures, the final semiconductor productive will come out defective or of inferior quality.

Precise temperature control is crucial because it gives improved process results. Depending on the chemical used, a higher temperature may increase the etch rate and reduce processing times. While a high etch rate is desirable, the amount of etching that occurs has to be tightly monitored because the amount of etching determines the size and shape of the microscopic structures in the silicon.

Modutek's process controls ensure that the right chemical concentration and quartz tank temperature are maintained at the correct levels, which results in precise etching control and excellent repeatability from one batch to the next. With Modutek's high-temperature quartz tanks, contamination during etching and cleaning of silicon wafers is significantly reduced. The temperature controls of the tanks provide precise settings during the process and for the subsequent batches.

Read the complete article, “How High Temperature Quartz Tanks Improve Silicon Wafer Processing,” for more details. Contact Modutek at 866-803-1533 or by email modutek@modutek.com if you have questions or would like to discuss your specific needs.