Specific Process Knowledge/Etch/Wet Silicon Nitride Etch: Difference between revisions
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[[Image:Wet_nitride_etch.JPG|300x300px|thumb|Wet nitride etch: positioned in cleanroom 4]] | [[Image:Wet_nitride_etch.JPG|300x300px|thumb|Wet nitride etch: positioned in cleanroom 4]] | ||
Wet Etching of silicon nitride is done in a dedicated laminar flow bench with an integrated quartz tank (Tiger Tank - TT-4). The quartz tank can take up to one 6" wafer carrier. The etch solution is initially 85 wt% H<math>3</math>PO<math>4</math> which is heated up to the boiling temperature - ca. 157 <sup>o</sup>C. Water is allowed to boil off thus raising the concentration and the boiling temperature of the solution until a boiling temperature of 180 <sup>o</sup>C is reached. Thereafter, the wafers are submerged into the bath and the water-cooled lid is closed to maintain the concentration and the boiling temperature. In some cases a lower boiling temperature is chosen - typically 160 <sup>o</sup>C - which lowers the etch rate and improves the selectivity R<sub>Si<sub>3</sub>N<sub>4</sub></sub> / R<sub>SiO<sub>2</sub></sub> | Wet Etching of silicon nitride is done in a dedicated laminar flow bench with an integrated quartz tank (Tiger Tank - TT-4). The quartz tank can take up to one 6" wafer carrier. The flow bench is placed in cleanroom 4. | ||
The etch solution is initially 85 wt% H<math>3</math>PO<math>4</math> which is heated up to the boiling temperature - ca. 157 <sup>o</sup>C. Water is allowed to boil off thus raising the concentration and the boiling temperature of the solution until a boiling temperature of 180 <sup>o</sup>C is reached. Thereafter, the wafers are submerged into the bath and the water-cooled lid is closed to maintain the concentration and the boiling temperature. In some cases a lower boiling temperature is chosen - typically 160 <sup>o</sup>C - which lowers the etch rate and improves the selectivity R<sub>Si<sub>3</sub>N<sub>4</sub></sub> / R<sub>SiO<sub>2</sub></sub> | |||