Difference between revisions of "Reactive ion etching"

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{{Infobox technology
 
{{Infobox technology
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|image = Rieoperation.svg
 
|technology = Plasma etching
 
|technology = Plasma etching
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|names = RIE
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|equipment = [[:Category:RIE equipment|List of RIE equipment]]
 
}}
 
}}
  
Reactive Ion Etching (RIE) is a high resolution mechanism for etching materials. Samples are first masked by one of many patterning processes. They are then placed into a vacuum chamber. Gases are introduced into the chamber and then activated by Rf or microwave power to create a plasma. This plasma consists of a wide variety of reactive species, ions, and electrons. A negative DC bias is induced at the substrate by the free electrons. This bias accelerates ions in the plasma perpendicular to the sample surface. This provides a directional physical motivating force to the etch. Generally some form of passivating component is incorporated such that the etch proceeds only where energetic ions strike the surface. A well tuned etch can be very [[Isotropy|anisotropic]] compared to [[:Category:Wet Bench|wet etches]] which are typically isotropic.
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Reactive ion etching (RIE) is a high resolution mechanism for [[etching]] materials using [[Plasma etching|reactive gas discharges]]. It is a highly controllable process that can process a wide variety of materials, including [[semiconductors]], [dielectrics]] and some [[Reactive metals|metals]]. One major advantage to RIE over other forms of etching is that the process can be designed to be highly [[Isotropy|anisotropic]], allowing for much finer resolution and higher aspect ratios.  For a detailed overview of RIE, please review the [https://docs.google.com/a/lnf.umich.edu/file/d/0B76AgohVTgqdamFiaE1mRk9mVmM/preview technology workshop].
  
RIE is a key enabling semiconductor technology allowing IC processes to continue to approach the range of a few nanometers. This same technology may be used as a machining process for nano and micro scale devices. As such, RIE is also key enabling technology for MEMS and nanofabrication.
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<!--RIE is a key enabling semiconductor technology allowing IC processes to continue to approach the range of a few nanometers. This same technology may be used as a machining process for nano and micro scale devices. As such, RIE is also key enabling technology for MEMS and nanofabrication.-->
  
==Technology Overview/Workshop Presentation==
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==Method of operation==
* [https://docs.google.com/a/lnf.umich.edu/file/d/0B76AgohVTgqdamFiaE1mRk9mVmM/preview RIE Workshop January 16th, 2015]
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Samples are first masked by one of many patterning processes.  They are then placed into a vacuum chamber.  Gases are introduced into the chamber and then activated by Rf or microwave power to create a plasma consisting of a wide variety of reactive species, ions, and electrons.  The reactive species are chosen for their ability to react chemically with the material being etched.  A negative DC bias is induced at the substrate by the free electrons which accelerates the ions towards the sample surface. The energy imparted by these ions reaching the surface greatly enhances the effectiveness of the chemical reaction and provides directionality to the etch.  Generally some form of [[Etch passivation|passivating]] component is incorporated such that the etch proceeds only where energetic ions strike the surface.
 +
 
 +
==Parameters==
 +
Many of the same parameters used in [[Plasma etching#Parameters|plasma etching]] apply to RIE, including pressure, gas composition, and generator power.  Of particular importance is the [[plasma generation]] method (commonly a parallel plate or ICP configuration), as they have different advantages depending on the material being etched.
 +
 
 +
===DC bias===
 +
A critical parameter specific to RIE is the DC bias applied to the sample, which directly affects the physicality of the etch.  Many materials (e.g. [[silicon dioxide|SiO<sub>2</sub>]]) require high activation energy to react with the gases in the reactor.  Other materials ([[silicon]], in particular) may be etched using a passivating component which must be removed on the surface being etched.  Still other materials have little to no reactivity and must be physically removed from the surface.
 +
 
 +
In most reactors, DC bias is not controlled directly, but will depend on the conductance of the plasma and the power applied to the sample.
 +
 
 +
==Deep reactive ion etching==
 +
{{main|Deep reactive ion etching}}
 +
 
 +
Deep reactive ion etching (DRIE), while often referring specifically to the [[Bosch process]], generally is any RIE used to etch high aspect ratio (> 10:1) features. This may be simply a longer, well controlled RIE etch, or may use a specific process such as [[cryogenic etching]] or the [[Bosch process]].  For all DRIE equipment at the LNF, please refer to the [[:Category:DRIE equipment|list of DRIE equipment]].
 +
 
 +
==Materials==
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RIE can be used to etch a wide variety of materials, including dielectrics, semiconductors, polymers, and some metals.  For information on etching specific materials, please review the sections below.
 +
 
 +
===Dielectric etching===
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not sure if I like this...
  
==Plasma generation==
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==Equipment==
===Capacitively coupled===
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Below is a general description of the RIE equipment at the LNF.  For a complete list, please see [[:Category:RIE equipment|list of RIE equipment]].
  
===Inductively coupled===
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==See also==
 +
<internal links>
  
===Downstream===
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==Notes==
Equipment
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<footnotes>
==Deep Reactive Ion Etching==
 
{{Hatnote|Main Article: [[Deep reactive ion etching]]}}
 
  
 
==References==
 
==References==
 +
<footnotes>
  
{{quote|text=Reactive-ion etching (RIE) is an etching technology used in microfabrication. It uses chemically reactive plasma to remove material deposited on wafers. The plasma is generated under low pressure (vacuum) by an electromagnetic field. High-energy ions from the plasma attack the wafer surface and react with it.|source=[[wikipedia:Reactive-ion_etching|Wikipedia]]}}
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==Further reading==
 +
* [https://docs.google.com/a/lnf.umich.edu/file/d/0B76AgohVTgqdamFiaE1mRk9mVmM/preview RIE Workshop January 16th, 2015]
  
 
[[Category:RIE]]
 
[[Category:RIE]]

Revision as of 16:22, 4 August 2015

Reactive ion etching
Rieoperation.svg
Technology Details
Other Names RIE
Technology Plasma etching
Equipment List of RIE equipment

Reactive ion etching (RIE) is a high resolution mechanism for etching materials using reactive gas discharges. It is a highly controllable process that can process a wide variety of materials, including semiconductors, [dielectrics][semiconductors]] and some metals. One major advantage to RIE over other forms of etching is that the process can be designed to be highly anisotropic, allowing for much finer resolution and higher aspect ratios. For a detailed overview of RIE, please review the technology workshop.


Method of operation

Samples are first masked by one of many patterning processes. They are then placed into a vacuum chamber. Gases are introduced into the chamber and then activated by Rf or microwave power to create a plasma consisting of a wide variety of reactive species, ions, and electrons. The reactive species are chosen for their ability to react chemically with the material being etched. A negative DC bias is induced at the substrate by the free electrons which accelerates the ions towards the sample surface. The energy imparted by these ions reaching the surface greatly enhances the effectiveness of the chemical reaction and provides directionality to the etch. Generally some form of passivating component is incorporated such that the etch proceeds only where energetic ions strike the surface.

Parameters

Many of the same parameters used in plasma etching apply to RIE, including pressure, gas composition, and generator power. Of particular importance is the plasma generation method (commonly a parallel plate or ICP configuration), as they have different advantages depending on the material being etched.

DC bias

A critical parameter specific to RIE is the DC bias applied to the sample, which directly affects the physicality of the etch. Many materials (e.g. SiO2) require high activation energy to react with the gases in the reactor. Other materials (silicon, in particular) may be etched using a passivating component which must be removed on the surface being etched. Still other materials have little to no reactivity and must be physically removed from the surface.

In most reactors, DC bias is not controlled directly, but will depend on the conductance of the plasma and the power applied to the sample.

Deep reactive ion etching

Deep reactive ion etching (DRIE), while often referring specifically to the Bosch process, generally is any RIE used to etch high aspect ratio (> 10:1) features. This may be simply a longer, well controlled RIE etch, or may use a specific process such as cryogenic etching or the Bosch process. For all DRIE equipment at the LNF, please refer to the list of DRIE equipment.

Materials

RIE can be used to etch a wide variety of materials, including dielectrics, semiconductors, polymers, and some metals. For information on etching specific materials, please review the sections below.

Dielectric etching

not sure if I like this...

Equipment

Below is a general description of the RIE equipment at the LNF. For a complete list, please see list of RIE equipment.

See also

<internal links>

Notes

<footnotes>

References

<footnotes>

Further reading