Specific Process Knowledge/Etch/ASE (Advanced Silicon Etch): Difference between revisions

← Older edit Newer edit →

VisualWikitext

@@ Line 10: / Line 10: @@
 [[image:ASE.jpg|300x300px|right|thumb|The ICP-DRIE tool at Danchip: STS ASE - positioned in cleanroom B-1]]
-The ICP-DRIE (Inductively Coupled Plasma - Deep Reactive Ion Etcher) tool at Danchip is manufactured by STS and is called the ASE (Advanced Silicon Etcher). Originally the main purpose of the ASE was etching of silicon using the Bosch process. However, after the acquisition of the [[Specific Process Knowledge/Etch/DRIE-Pegasus|DRIE-Pegasus]] the ASE now only serves as backup silicon dry etcher and is also used as a polymer etcher. '''From around February 2018 this machine will turn into a "dirty" machine meaning that samples with up to 4 cm2 of metal on the surface will be allowed to process. Extra gasses will be added to the machine during this summer to allow SiO2 and SiN etching. Using these gasses may affect the conditioning of the chamber and thereby the stability of the current processes. Any clean processes and sensitive processes should be moved to the DRIEs) during this autumn (2017).'''
+The ASE was the first ICP (Inductively coupled plasma) tool at Danchip. It was manufactured by STS and is called the ASE (Advanced Silicon Etcher). Originally the main purpose of the ASE was etching of silicon using the Bosch process. However, after the acquisition of the [[Specific Process Knowledge/Etch/DRIE-Pegasus|DRIE-Pegasus]] and the retirement of our old RIE's the ASE will only serve as a "dirty" plasma etcher, etching silicon, Silicon oxide and silicon nitride on wafers with small amount of metals exposed and as a polymer etcher. The rule is that samples with up to 4 cm2 of metal on the surface will be allowed to process. Extra gasses was been added to the machine during the summer in 2017 to allow SiO2 and SiN etching. Using these gasses may affect the conditioning of the chamber and thereby the stability of processes. Any clean processes and sensitive processes should take place in to the DRIEs or elsewhere.
-'''The Bosch process: Etching of silicon'''
-The Bosch process uses alternation between an etch cycle and a passivation cycle. Introducing a passivation step in an etch process is very beneficial for the control of the angle of the sidewalls in the etch process because it allows us to cover them with a protective layer that suppresses the isotropic etching. Combined with the high plasma density in the ICP chamber, the excellent sidewall control enables us to etch high aspect ratio structures in silicon with very high etch rates.
 In the case of the silicon etching on the ASE, an etch phase with SF<sub>6</sub> and O<sub>2</sub> alternates with a passivation phase with C<sub>4</sub>F<sub>8</sub>.