Specific Process Knowledge/Etch/DRIE-Pegasus/TrenchCharacterisation: Difference between revisions

; Etched depth (nm or µm)

: The etched depth (ED) is rather self explanatory: ED <math>\times</math> PS

; Etch rate (nm or µm per min.)

: Divide the etched depth (ED) by the etch time (ET) of the process:  <math> \tfrac{\mathrm{ED} \times \mathrm{PS}}{\mathrm{ET}}</math>   

; Sidewall bowing (%)

: The sidewall bowing is a measure of how much the sidewall profile deviates from a straight line - regardless of what angle it is at:

: <math> \sin(\cos^{-1}(\tfrac{\mathrm{TW-BW}}{2 \sqrt{\mathrm{ED}^2+(\tfrac{\mathrm{TW}-\mathrm{BW}}{2})^2}})) \times \tfrac{\mathrm{MW} - \tfrac{\mathrm{TW}+\mathrm{BW}}{2}}{2\sqrt{\mathrm{ED}^2+(\tfrac{\mathrm{BW}-\mathrm{TW}}{2})^2}}</math>

: or  

; Mask etch rate (nm per min.)

: <math> \tfrac{(\mathrm{MT-MR}) \times \mathrm{PS}}{\mathrm{ET}} </math>

; CD loss (nm per edge)

: <math> \tfrac{(\mathrm{MO-TW})}{2 } </math>

; Sidewall angle (degrees)

: <math> \cos^{-1}(\tfrac{

\mathrm{TW-BW}}{2 \sqrt{\mathrm{ED}^2+(\tfrac{\mathrm{TW}-\mathrm{BW}}{2})^2}}) </math>

: or  

   

: <math> \cos^{1}(\tfrac{

\alpha}{\sqrt{\mathrm{ED}^2+\alpha^2}}) </math> with <math> \alpha = \tfrac{\mathrm{TW}-\mathrm{BW}}{2} </math>