Difference between revisions of "Fluorine ICP Etcher (PlasmaTherm/SLR Fluorine ICP)"

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|picture=SiDeep.jpg
 
|picture=SiDeep.jpg
 
|type = Dry Etch
 
|type = Dry Etch
|super= Don Freeborn
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|super= Brian Lingg
 
|phone= 805-893-3918x216
 
|phone= 805-893-3918x216
 
|location=Bay 2
 
|location=Bay 2
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= About =
 
   
 
=About=
The SiRIE system is a Plasma-Therm 770 SLR series system with a loadlock. The system has an Inductively Coupled Plasma (ICP) coil and a capactively coupled substrate RF supply to independently control plasma density and ion energy in the system. This system is dedicated to deep etching in silicon for MEMs structures. The Bosch process is used for obtaining the deep, vertical, high aspect ratio structures. This process cycles between a polymer deposition cycle using C<sub>4</sub>F<sub>8</sub> gas and no substrate bias, and an etching cycle using a SF<sub>6</sub> / Ar mixture with substrate bias. The system is fully computer controlled in all aspects of the pumping cycles and process control, and can be programmed by the user. The fixturing is configured for 4" diameter Si wafers and uses a clamp to hold the sample on the RF chuck.
 
   
 
The system is a Plasma-Therm 770 SLR series system with a loadlock. The system has an Inductively Coupled Plasma (ICP) coil and a capactively coupled substrate RF supply to independently control plasma density and ion energy in the system. Helium back-side cooling is available to keep the sample cool during the etch. The system is fully computer controlled in all aspects of the pumping cycles and process control, and can be programmed by the user.
The materials allowed in the system are limited to Silicon, SiO<sub>2</sub>, Si<sub>3</sub>N<sub>4</sub>, SiO<sub>X</sub>N<sub>Y</sub>, and polymer films such as photoresist, PMMA, and polyimide. Other materials can be placed in the chamber, such as metal layers on the surface, only if they will remain completely protected from the plasma by an allowed material during the entire etch. Some alternate stop-etch materials may be allowed upon discussion with facility staff.
 
   
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The system is generally meant for any fluorine-containing etch, which is typically for etching materials like SiO<sub>2</sub>, Si<sub>3</sub>N<sub>4</sub>, Silicon, or other materials with voltalee fluoride etch products.
He back-side cooling is used to keep the sample cool during the etch. This is very important as the polymer passivation layer is chemically etched away by the fluorine gas at elevated temperatures, resulting in loss of profile control. Pieces of wafers can be mounted onto 4" silicon wafers using thin, uniform, bubble-free hard baked photoresist. The etch rate is dependent on the open area of silicon (macro-loading effect) with large open area samples etching slower than small open area samples. Features with a high aspect ratio will also etch slower than more open areas. This is known as RIE lag or the micro-loading effect.
 
   
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The fixturing is configured for 4" diameter Si wafers and uses a cermaic clamp on the outer ~5mm of the 100mm wafer to hold the sample on the RF chuck.
= Detailed Specifications =
 
   
  +
Smaller samples can be mounted onto 100mm carrier wafers, either with no adhesive (sample temperature will be higher), or with Santovac oil for better thermal cooling. However, great care must be taken to ensure no oil, photoresist or small pieces are placed on the outer 5mm of the carrier wafer, as the ceramic clamp will physically press on this out region, potentially causing stiction or breakage if foreign or sticky substances are in those regions.
*1000 W ICP coil power at 2 MHz and 500 W substrate bias at 13.56 MHz plasma generators
 
  +
*C<sub>4</sub>F<sub>8</sub>, SF<sub>6</sub>, O<sub>2</sub>, Ar, N<sub>2</sub> gases available
 
  +
The in-situ [[Laser Etch Monitoring|laser monitor]] installed on the chamber allows for repeatable etches and endpoint detection via continuous optical monitoring of the wafer reflectivity in a user-determined location, through a porthole on the chamber.
*He-back-side cooling
 
  +
*Windows-based computer control of process and wafer handling
 
 
=Detailed Specifications=
*Allowed materials: Silicon, SiO<sub>2</sub>, Si<sub>3</sub>N<sub>4</sub>, SiO<sub>X</sub>N<sub>Y</sub>, and polymer films such as photoresist, PMMA, and polyimide; other stop-etch materials on request
 
  +
*Realized etch rates (including passivation steps) of &gt; 3 um / min. Using the standard Plasma Therm recipe, a nominal etch rate of 2 um / min. is achieved; etch rate dependent on conditions and open area
 
 
*1000 W ICP coil power at 2 MHz and 500 W substrate bias at 13.56 MHz plasma generators
 
*C<sub>4</sub>F<sub>8</sub>, SF<sub>6</sub>, O<sub>2</sub>, Ar, N<sub>2,</sub> CHF<sub>3,</sub> CF<sub>4</sub> gases available
 
*He-back-side cooling
  +
*Single 100mm/4-inch wafer handling with physical topside clamp, contacting outer 5mm of wafer.
  +
**Small samples may be mounted with oil or no adhesive, but must be far away from this 5mm edge exclusion zone.
  +
**No photoresist or oil is allowed to contact the clamp, or wafers will get stuck and possibly break in the chamber.
 
*Windows-based computer control of process and wafer handling
  +
*[[Laser Etch Monitoring|Laser endpoint monitoring]] with camera and simulation software, for repeatable etching - see: [[Laser Etch Monitoring|Intellemetrics LEP 500]]
  +
  +
=Documentation=
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*{{file|Running_a_process_on_Plasma_Therm_SLR.pdf|Fluorine Etcher Operating Instructions (Cortex Software)}}
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*{{file|How to restart the software on Si Deep Etch.pdf|How to restart software on Plasma-Therm Cortex Software}}
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*[[Laser Etch Monitoring|Laser Monitor procedures]]
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  +
=Recipes=
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*Recipes > [[Dry Etching Recipes|Dry Etching]] > [https://wiki.nanotech.ucsb.edu/w/index.php?title=ICP_Etching_Recipes#PlasmaTherm.2FSLR_Fluorine_Etcher '''PlasmaTherm/SLR Fluorine Etcher''']
  +
**Starting point recipes for the FL-ICP, including SiO<sub>2</sub> and Si etches.
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**''Historical Data'' records "calibration" etches to test tool performance.
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*You can see a full list of all tools and all materials able to be etched by each on our [[Dry Etching Recipes|Dry Etching Recipes Table]].

Revision as of 17:13, 1 October 2021

Fluorine ICP Etcher (PlasmaTherm/SLR Fluorine ICP)
SiDeep.jpg
Tool Type Dry Etch
Location Bay 2
Supervisor Brian Lingg
Supervisor Phone (805) 893-8145
Supervisor E-Mail lingg_b@ucsb.edu
Description SiRIE Based Flourine Etcher for Bosch MEMS Processes
Manufacturer Plasmatherm (Unaxis)
Dry Etch Recipes
Sign up for this tool



About

The system is a Plasma-Therm 770 SLR series system with a loadlock. The system has an Inductively Coupled Plasma (ICP) coil and a capactively coupled substrate RF supply to independently control plasma density and ion energy in the system. Helium back-side cooling is available to keep the sample cool during the etch. The system is fully computer controlled in all aspects of the pumping cycles and process control, and can be programmed by the user.

The system is generally meant for any fluorine-containing etch, which is typically for etching materials like SiO2, Si3N4, Silicon, or other materials with voltalee fluoride etch products.

The fixturing is configured for 4" diameter Si wafers and uses a cermaic clamp on the outer ~5mm of the 100mm wafer to hold the sample on the RF chuck.

Smaller samples can be mounted onto 100mm carrier wafers, either with no adhesive (sample temperature will be higher), or with Santovac oil for better thermal cooling. However, great care must be taken to ensure no oil, photoresist or small pieces are placed on the outer 5mm of the carrier wafer, as the ceramic clamp will physically press on this out region, potentially causing stiction or breakage if foreign or sticky substances are in those regions.

The in-situ laser monitor installed on the chamber allows for repeatable etches and endpoint detection via continuous optical monitoring of the wafer reflectivity in a user-determined location, through a porthole on the chamber.

Detailed Specifications

  • 1000 W ICP coil power at 2 MHz and 500 W substrate bias at 13.56 MHz plasma generators
  • C4F8, SF6, O2, Ar, N2, CHF3, CF4 gases available
  • He-back-side cooling
  • Single 100mm/4-inch wafer handling with physical topside clamp, contacting outer 5mm of wafer.
    • Small samples may be mounted with oil or no adhesive, but must be far away from this 5mm edge exclusion zone.
    • No photoresist or oil is allowed to contact the clamp, or wafers will get stuck and possibly break in the chamber.
  • Windows-based computer control of process and wafer handling
  • Laser endpoint monitoring with camera and simulation software, for repeatable etching - see: Intellemetrics LEP 500

Documentation

Recipes