Basic Information / Capabilities

This Tegal 110 S/DE DRIE system is a deep reactive ion etcher designed for high-aspect-ratio etching of silicon using Bosch-type processes. The system supports both deep silicon etching and dry etching of silicon oxide. Multiple standard process recipes are available, optimized for either high aspect ratio structures or high etch rate processing.

Technical Specification

Process Specification

Silicon DRIE (std bosch)

Available process modes:

MSL recipes:

Silicon High Aspect Ratio                                     SI_HAR_MSL_XTR, Etch rate 2.0 um/min*

Silicon High Etch Rate                                          SI_HER_MSL_XTR, Etch rate 15 um/min*

Silicon High Etch Rate High Selectivity                 SI_HER_2200W, Etch rate 10 um/min*

* Etch rate is dependent on the total area to be etched, and size of the opening window. 

Opening windows less than 30 um should experience lower etch rates.

Etch areas larger than 70% the total area of a 4'' wafer should experience lower etch rates.

Selectivity SI_HER_MSL_XTR (approx):
• ~80:1 (photoresist)
• ~200:1 (SiO2)

Selectivity Si/Mask for SI_HER_2200W (approx):
• ~250-290:1 (photoresist AZ10XT, similar for S1813)
• ~1000:1 (thermal SiO2)

Aluminum masks provide very high selectivity to silicon; however, sputtering and redeposition may cause grass formation. When aluminum masks are used, the HER process is recommended to mitigate redeposition effects.

Etching through the wafer no longer requires Al mask. 

Restrictions

• Wafer / sample size: 100 mm standard / 150 mm with reconfiguration.

• DRIE tool optimized for high-aspect-ratio silicon etching; non-standard materials or processes require approval from lab staff.

• Chips / small pieces require special mounting and approval.

• Forbidden non-flat wafers, cracked wafers. 

• Always check if the fuse for Load Match and Tune is on. If not, turn it on. If you're not sure, call the tool responsibles.

• Cracked, chipped wafers are not allowed. Check carefully on the wafer's edge.

• Aluminum mask or Aluminum tape only allowed when Si_HER_MSL_XTR is used. Other recipes require normal Kappton tape, Resist, Oxide or Nitride as mask material. Otherwise, micromask problem will happen.

Chemistry / Materials

Process gas:

Silicon DRIE chamber:
SF6, C4F8, O2, He