Specific Process Knowledge/Etch/DRIE-Pegasus/showerheadchange - Revision history

Jmli at 08:32, 4 September 2025

2025-09-04T08:32:36Z

← Older revision		Revision as of 10:32, 4 September 2025
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	<!--Checked for updates on 14/5-2018 - ok/jmli -->		<!--Checked for updates on 14/5-2018 - ok/jmli -->
	<!-- Page reviewed 9/8-2022 jmli -->		<!-- Page reviewed 9/8-2022 jmli -->
			<!--Checked for updates on 4/9-2025 - ok/jmli -->

Jmli: /* Modification of showerhead on Pegasus 1 in december 2014 */

2023-04-28T10:25:37Z

Modification of showerhead on Pegasus 1 in december 2014

← Older revision		Revision as of 12:25, 28 April 2023
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	<!--Checked for updates on 2/02-2023 - ok/jmli -->		<!--Checked for updates on 2/02-2023 - ok/jmli -->

	This page describes why the showerhead has been changed and what process changes have been found~~. SPTS calls this modification the 'High Flow Plenum upgrade'~~.		This page describes why the showerhead has been changed and what process changes have been found.

	== Motivation ==		== Motivation ==

Jmli: /* Motivation */

2023-04-28T10:25:07Z

Motivation

← Older revision		Revision as of 12:25, 28 April 2023
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	== Motivation ==		== Motivation ==

	The showerhead that distributes the process gasses inside the Pegasus plasma source was changed. In the old design, the showerhead had a number of ~~300 µm diameter~~ holes intended to distribute the gas uniformly inside the plasma source. The passage through the holes had a flow resistance that would cause the gasses coming from the MFC in a Bosch process to get mixed up - in this way working against the separation of the etch and dep cycles.		The showerhead that distributes the process gasses inside the Pegasus plasma source was changed. In the old design, the showerhead had a number of holes intended to distribute the gas uniformly inside the plasma source. The passage through the holes had a flow resistance that would cause the gasses coming from the MFC in a Bosch process to get mixed up - in this way working against the separation of the etch and dep cycles.

	In the new design, the gas flow resistance has been reduced by ~~using 1 mm~~ diameter holes in the showerhead instead. This has no impact on processes that have a continuous gas flow - i.e. processes that are not switched. However, for processes with several gas flows that switch on and off, the switching from one gas flow to another will be much more well defined. This has enabled us to run Bosch processes with shorter cycles times. Shorter cycles times means smaller scallops and hence lower roughness and better control. We have not seen any changes to the uniformity of the plasma nor any other side effect.		In the new design, the gas flow resistance has been reduced by increasing the diameter holes in the showerhead instead. This has no impact on processes that have a continuous gas flow - i.e. processes that are not switched. However, for processes with several gas flows that switch on and off, the switching from one gas flow to another will be much more well defined. This has enabled us to run Bosch processes with shorter cycles times. Shorter cycles times means smaller scallops and hence lower roughness and better control. We have not seen any changes to the uniformity of the plasma nor any other side effect. The modification was also done on Pegasus 2 and 3 before we started using them.

	~~This modification is described by SPTS [[Media:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf\| High Flow Plenum Upgrade]].~~

	The modification was also done on Pegasus 2 and 3 before we started using them.

	== Comparison of continuous processes on Pegasus 1==		== Comparison of continuous processes on Pegasus 1==

Jmli at 14:10, 2 February 2023

2023-02-02T14:10:41Z

← Older revision		Revision as of 16:10, 2 February 2023
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	= Modification of showerhead on Pegasus 1 in december 2014 =		= Modification of showerhead on Pegasus 1 in december 2014 =
			{{Template:Author-jmli1}}
			<!--Checked for updates on 2/02-2023 - ok/jmli -->

	This page describes why the showerhead has been changed and what process changes have been found. SPTS calls this modification the 'High Flow Plenum upgrade'.		This page describes why the showerhead has been changed and what process changes have been found. SPTS calls this modification the 'High Flow Plenum upgrade'.

Jmli at 09:26, 9 August 2022

2022-08-09T09:26:34Z

← Older revision		Revision as of 11:26, 9 August 2022
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	'''Feedback to this page''': '''[mailto:labadviser@~~danchip~~.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.~~danchip~~.dtu.dk/index.php/Specific_Process_Knowledge/Etch/DRIE-Pegasus/nanoetch click here]'''		'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Etch/DRIE-Pegasus/nanoetch click here]'''
	<!--Checked for updates on 14/5-2018 - ok/jmli -->		<!--Checked for updates on 14/5-2018 - ok/jmli -->
			<!-- Page reviewed 9/8-2022 jmli -->

Jmli: /* Motivation */

2020-03-18T10:34:31Z

Motivation

← Older revision		Revision as of 12:34, 18 March 2020
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	This modification is described by SPTS [[Media:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf\| High Flow Plenum Upgrade]].		This modification is described by SPTS [[Media:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf\| High Flow Plenum Upgrade]].

	The modification was also done on Pegasus 2 before we started using it.		The modification was also done on Pegasus 2 and 3 before we started using them.

	== Comparison of continuous processes on Pegasus 1==		== Comparison of continuous processes on Pegasus 1==

Jmli: /* Motivation */

2018-07-30T10:46:53Z

Motivation

← Older revision		Revision as of 12:46, 30 July 2018
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	In the new design, the gas flow resistance has been reduced by using 1 mm diameter holes in the showerhead instead. This has no impact on processes that have a continuous gas flow - i.e. processes that are not switched. However, for processes with several gas flows that switch on and off, the switching from one gas flow to another will be much more well defined. This has enabled us to run Bosch processes with shorter cycles times. Shorter cycles times means smaller scallops and hence lower roughness and better control. We have not seen any changes to the uniformity of the plasma nor any other side effect.		In the new design, the gas flow resistance has been reduced by using 1 mm diameter holes in the showerhead instead. This has no impact on processes that have a continuous gas flow - i.e. processes that are not switched. However, for processes with several gas flows that switch on and off, the switching from one gas flow to another will be much more well defined. This has enabled us to run Bosch processes with shorter cycles times. Shorter cycles times means smaller scallops and hence lower roughness and better control. We have not seen any changes to the uniformity of the plasma nor any other side effect.

	This modification is described by SPTS [[~~:File~~:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf]].		This modification is described by SPTS [[Media:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf\| High Flow Plenum Upgrade]].

	The modification was also done on Pegasus 2 before we started using it.		The modification was also done on Pegasus 2 before we started using it.

Jmli: /* Comparison of switched processes */

2018-06-26T12:38:10Z

Comparison of switched processes

← Older revision		Revision as of 14:38, 26 June 2018
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	\|}		\|}

	== Comparison of switched processes ==		== Comparison of switched processes on Pegasus 1==

Jmli: /* Comparison of continuous processes */

2018-06-26T12:37:55Z

Comparison of continuous processes

← Older revision		Revision as of 14:37, 26 June 2018
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	The modification was also done on Pegasus 2 before we started using it.		The modification was also done on Pegasus 2 before we started using it.

	== Comparison of continuous processes ==		== Comparison of continuous processes on Pegasus 1==

	=== Black silicon recipe ===		=== Black silicon recipe ===

Jmli: /* Motivation */

2018-06-26T12:37:21Z

Motivation

← Older revision		Revision as of 14:37, 26 June 2018
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	This modification is described by SPTS [[:File:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf]].		This modification is described by SPTS [[:File:SPTS High Flow Plenum Upgrade for Pegasus Nov 2012.pdf]].

			The modification was also done on Pegasus 2 before we started using it.

	== Comparison of continuous processes ==		== Comparison of continuous processes ==