Specific Process Knowledge/Etch/Etching of Silicon Nitride: Difference between revisions
| Line 5: | Line 5: | ||
==Comparison of wet Silicon Nitride etch and RIE etch for etching of Silicon Nitride== | ==Comparison of wet Silicon Nitride etch and RIE etch for etching of Silicon Nitride== | ||
{| border="1" cellspacing="0" cellpadding="4" align="center" | {| border="1" cellspacing="0" cellpadding="4" align="center" | ||
! | ! | ||
! Wet Silicon Nitride etch | ! Wet Silicon Nitride etch | ||
! Buffered HF (BHF) | ! Buffered HF (BHF) | ||
! RIE | ! RIE | ||
|- | |- valign="top" | ||
! General description | |||
| | | | ||
*Isotropic etch | *Isotropic etch | ||
*Well suited for removing all nitride on a wafer surface (nitride strip) without a mask. High selectivity Si<sub>3</sub>N<sub>4</sub>/Si (>100) and Si<sub>3</sub>N<sub>4</sub>/SiO<sub>2</sub> (>20) @ 180 C. | *Well suited for removing all nitride on a wafer surface (nitride strip) without a mask. High selectivity Si<sub>3</sub>N<sub>4</sub>/Si (>100) and Si<sub>3</sub>N<sub>4</sub>/SiO<sub>2</sub> (>20) @ 180 C. | ||
| | | | ||
*Isotropic etch | *Isotropic etch | ||
*Well suited for removing all PECVD nitride on a wafer surface (nitride strip) without a mask. Etches LPCVD nitride very slowly | *Well suited for removing all PECVD nitride on a wafer surface (nitride strip) without a mask. Etches LPCVD nitride very slowly | ||
| | | | ||
*Anisotropic etch: vertical sidewalls | *Anisotropic etch: vertical sidewalls | ||
|- | |- valign="top" | ||
!Possible masking materials: | |||
| | | | ||
*Silicon Oxide | *Silicon Oxide | ||
| Line 35: | Line 35: | ||
*Chromium (ONLY RIE2!) | *Chromium (ONLY RIE2!) | ||
*Other metals if they cover less than 5% of the wafer area (ONLY RIE2!) | *Other metals if they cover less than 5% of the wafer area (ONLY RIE2!) | ||
|- | |- valign="top" | ||
!Etch rate | |||
| | | | ||
*Si<sub>3</sub>N<sub>4</sub> @ 180 <sup>o</sup>C: ~84 Å/min | *Si<sub>3</sub>N<sub>4</sub> @ 180 <sup>o</sup>C: ~84 Å/min | ||
| Line 44: | Line 44: | ||
| | | | ||
*Typically 40-50 nm/min can be increased or decreased by using other recipe parameters. | *Typically 40-50 nm/min can be increased or decreased by using other recipe parameters. | ||
|- | |- valign="top" | ||
!Batch size | |||
| | | | ||
*1-25 wafers at a time | *1-25 wafers at a time | ||
| Line 52: | Line 52: | ||
| | | | ||
*1 wafer at a time | *1 wafer at a time | ||
|- | |- valign="top" | ||
!Size of substrate | |||
| | | | ||
*4" wafers | *4" wafers | ||
| Line 60: | Line 60: | ||
| | | | ||
*4" wafers or smaller pieces | *4" wafers or smaller pieces | ||
|- | |- valign="top" | ||
!Allowed materials | |||
| | | | ||
*Silicon | *Silicon | ||