Specific Process Knowledge/Etch/DRIE-Pegasus/System-description - Revision history

Jmli at 08:33, 4 September 2025

2025-09-04T08:33:35Z

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	== Description of the Bosch process at the DRIE-Pegasus ==		== Description of the Bosch process at the DRIE-Pegasus ==

Jmli: /* The Claritas endpoint system */

2023-04-28T11:15:56Z

The Claritas endpoint system

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	== The Claritas endpoint system ==		== The Claritas endpoint system ==

	This section applies to Pegasus 1.		This section applies to Pegasus 1. Too bad that it is empty so far...

	~~The plasma of any dry etch process emits light as the gas constituents ( gas molecules, ions and radicals) deexcite from high energy states~~. ~~Every gas molecule, ions etc~~. ~~have unique vibrational and rotational energy states~~.

Jmli: /* The Picoscope */

2023-04-28T11:15:13Z

The Picoscope

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	== The Picoscope ==		== The Picoscope ==

	~~This section applies to Pegasus 1, 2 and 3.~~

	The process monitoring on Pegasus 1, 2 and 3 has been dramatically improved with the installation of the Picoscope. Click [[Specific Process Knowledge/Etch/DRIE-Pegasus/picoscope\|'''HERE''']] to access a page on the Picoscope only.		The process monitoring on Pegasus 1, 2 and 3 has been dramatically improved with the installation of the Picoscope. Click [[Specific Process Knowledge/Etch/DRIE-Pegasus/picoscope\|'''HERE''']] to access a page on the Picoscope only.

Jmli: /* RF Matching */

2023-04-28T11:14:46Z

RF Matching

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	== RF Matching ==		== RF Matching ==
	~~--[[User:jmli\|jmli]] ([[User talk:jmli\|talk]]) 15 May 2018‎~~

	~~These sections and subsection apply to all Pegasus tools.~~

	=== RF matching in general ===		=== RF matching in general ===

Jmli: /* Modification of the showerhead */

2023-04-28T10:29:21Z

Modification of the showerhead

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	== Modification of the showerhead==		== Modification of the showerhead==
	~~--[[User:jmli\|jmli]] ([[User talk:jmli\|talk]]) 20 November 2015‎~~		This section applies to all Pegasus tools.

	This section applies to all Pegasus tools.

	It is clear that optimizing the Bosch processes on the Pegasus can be done in countless ways. Reducing the cycle time is a very convenient way of getting rid of, or at least reducing, scallops. The faster the process switches the smaller the scallops will be. However, at some point the hardware (MFS's, RF generators, APC valve) cannot keep up with the demand and the process will essentially be continuous causing the Bosch process to break down. In its original setup, the Pegasus had standard processes with cycle durations down to 2 seconds. The hardware on the Pegasus is indeed very fast and allows faster switching. The limiting factor in the Bosch process was identified by Henri Jansen - and we have taken steps to improve this as described below.		It is clear that optimizing the Bosch processes on the Pegasus can be done in countless ways. Reducing the cycle time is a very convenient way of getting rid of, or at least reducing, scallops. The faster the process switches the smaller the scallops will be. However, at some point the hardware (MFS's, RF generators, APC valve) cannot keep up with the demand and the process will essentially be continuous causing the Bosch process to break down. In its original setup, the Pegasus had standard processes with cycle durations down to 2 seconds. The hardware on the Pegasus is indeed very fast and allows faster switching. The limiting factor in the Bosch process was identified by Henri Jansen - and we have taken steps to improve this as described below.

Jmli: /* Processing options on the Pegasus */

2023-04-28T10:29:09Z

Processing options on the Pegasus

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	== Processing options on the Pegasus ==		== Processing options on the Pegasus ==

	This section applies to all Pegasus tools.		This section applies to all Pegasus tools.

	The Pegasus has a lot of advanced processing options.		The Pegasus has a lot of advanced processing options.

Jmli: /* Processing options on the Pegasus */

2023-04-28T10:22:08Z

Processing options on the Pegasus

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	== Processing options on the Pegasus ==		== Processing options on the Pegasus ==
	~~--[[User:jmli\|jmli]] ([[User talk:jmli\|talk]]) 26 November 2012~~

	This section applies to all Pegasus tools.		This section applies to all Pegasus tools.

Jmli: /* Description of the Bosch process at the DRIE-Pegasus */

2023-04-28T10:17:44Z

Description of the Bosch process at the DRIE-Pegasus

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	**the ion bombardment driven by the platen power ''first'' removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces)		**the ion bombardment driven by the platen power ''first'' removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces)
	**''then'' as the bottom of the structures are opened the etch of silicon itself starts.		**''then'' as the bottom of the structures are opened the etch of silicon itself starts.
	[[Image:boostdelay4b.jpg \|400x400px\|thumb\|The etch cycle may be split into three parts, Boost, Delay and Main, where process parameters such as pressure, gas flows or RF powers have different values. The red curve shows the possible characteristics of the platen power. {{~~photo1~~}}]]		[[Image:boostdelay4b.jpg \|400x400px\|thumb\|The etch cycle may be split into three parts, Boost, Delay and Main, where process parameters such as pressure, gas flows or RF powers have different values. The red curve shows the possible characteristics of the platen power. {{image1}}]]
	Here, it is clear that one can distinguish two phases of the etch cycle; one where the ion bombardment removes the polymer and one where the actual etching of silicon takes place. Considering what process conditions are favorable we realize that		Here, it is clear that one can distinguish two phases of the etch cycle; one where the ion bombardment removes the polymer and one where the actual etching of silicon takes place. Considering what process conditions are favorable we realize that
	#the ion bombardment requires a low pressure in order for the ions to have a long mean free path and hence good directionality. Also, a high platen power is required to drive the ion bombardment.		#the ion bombardment requires a low pressure in order for the ions to have a long mean free path and hence good directionality. Also, a high platen power is required to drive the ion bombardment.

Jmli: /* Description of the Bosch process at the DRIE-Pegasus */

2023-04-28T10:16:05Z

Description of the Bosch process at the DRIE-Pegasus

← Older revision		Revision as of 12:16, 28 April 2023
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	**the ion bombardment driven by the platen power ''first'' removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces)		**the ion bombardment driven by the platen power ''first'' removes the passivation layer on the surfaces directly exposed to the ions (i.e. horizontal surfaces)
	**''then'' as the bottom of the structures are opened the etch of silicon itself starts.		**''then'' as the bottom of the structures are opened the etch of silicon itself starts.
	[[Image:boostdelay4b.jpg \|400x400px\|thumb\|The etch cycle may be split into three parts, Boost, Delay and Main, where process parameters such as pressure, gas flows or RF powers have different values. The red curve shows the possible characteristics of the platen power.]]		[[Image:boostdelay4b.jpg \|400x400px\|thumb\|The etch cycle may be split into three parts, Boost, Delay and Main, where process parameters such as pressure, gas flows or RF powers have different values. The red curve shows the possible characteristics of the platen power. {{photo1}}]]
	Here, it is clear that one can distinguish two phases of the etch cycle; one where the ion bombardment removes the polymer and one where the actual etching of silicon takes place. Considering what process conditions are favorable we realize that		Here, it is clear that one can distinguish two phases of the etch cycle; one where the ion bombardment removes the polymer and one where the actual etching of silicon takes place. Considering what process conditions are favorable we realize that
	#the ion bombardment requires a low pressure in order for the ions to have a long mean free path and hence good directionality. Also, a high platen power is required to drive the ion bombardment.		#the ion bombardment requires a low pressure in order for the ions to have a long mean free path and hence good directionality. Also, a high platen power is required to drive the ion bombardment.

Jmli: /* Description of the Bosch process at the DRIE-Pegasus */

2023-04-28T10:15:30Z

Description of the Bosch process at the DRIE-Pegasus

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	<!-- revised 28/4-2023 by jmli -->		<!-- revised 28/4-2023 by jmli -->
	{{Author-jmli1}}		{{Author-jmli1}}
	This section applies to all Pegasus tools. For Pegasus 4, however, it is less important as dielectrics etches are continuous.
			This section applies to all Pegasus tools. For Pegasus 4, however, it is less important as dielectrics etches are continuous.

	The DRIE-Pegasus tools take the well established Bosch process known from the [[Specific_Process_Knowledge/Etch/ASE_(Advanced_Silicon_Etch)\|ASE]] a significant step further. In the ASE the Bosch process has two cycles, etch and passivation. During each cycle the process parameters are kept constant:		The DRIE-Pegasus tools take the well established Bosch process known from the [[Specific_Process_Knowledge/Etch/ASE_(Advanced_Silicon_Etch)\|ASE]] a significant step further. In the ASE the Bosch process has two cycles, etch and passivation. During each cycle the process parameters are kept constant: