Working with KOH - Revision history

Harry: /* Mixing KOH pellets and etching */

2026-09-10T15:53:52Z

Mixing KOH pellets and etching

← Older revision		Revision as of 15:53, 10 September 2026
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	** KOH pellets		** KOH pellets
	* Set up your equipment		* Set up your equipment
			** Turn on MQ 30-minute timer. Flush the MQ for 30 seconds
	** Fill 2L beaker with water to create a hotbath and add a magnetic stirring pill.		** Fill 2L beaker with water to create a hotbath and add a magnetic stirring pill.
	** Balance the scale.		** Balance the scale.

Harry at 15:37, 10 September 2026

2026-09-10T15:37:10Z

← Older revision		Revision as of 15:37, 10 September 2026
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	At NBI cleanroom, we use as standard a 28% w/w KOH solution. The etch rate and the selectivity towards a SiO2 mask depends on the temperature. We normally use a temperature of 80°C but it may reduce it to, e.g., 60 °C or 70°C for a higher-precision timed etch.		At NBI cleanroom, we use as standard a 28% w/w KOH solution. The etch rate and the selectivity towards a SiO2 mask depends on the temperature. We normally use a temperature of 80°C but it may reduce it to, e.g., 60 °C or 70°C for a higher-precision timed etch.

	Before doing any chemical process related to KOH you are obligated to read and understand the current wiki page as well as the relevant [APV_KOH_V1.pdf Risk Assessment].		Before doing any chemical process related to KOH you are obligated to read and understand the current wiki page as well as the relevant [[Media:APV_KOH_V1.pdf \| Risk Assessment]].

	=Properties and guidelines=		=Properties and guidelines=

Harry at 15:35, 10 September 2026

2026-09-10T15:35:19Z

← Older revision		Revision as of 15:35, 10 September 2026
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	At NBI cleanroom, we use as standard a 28% w/w KOH solution. The etch rate and the selectivity towards a SiO2 mask depends on the temperature. We normally use a temperature of 80°C but it may reduce it to, e.g., 60 °C or 70°C for a higher-precision timed etch.		At NBI cleanroom, we use as standard a 28% w/w KOH solution. The etch rate and the selectivity towards a SiO2 mask depends on the temperature. We normally use a temperature of 80°C but it may reduce it to, e.g., 60 °C or 70°C for a higher-precision timed etch.

			Before doing any chemical process related to KOH you are obligated to read and understand the current wiki page as well as the relevant [APV_KOH_V1.pdf Risk Assessment].

	=Properties and guidelines=		=Properties and guidelines=

Harry: /* Mixing KOH (with pellets) */

2026-09-10T13:11:59Z

Mixing KOH (with pellets)

← Older revision		Revision as of 13:11, 10 September 2026
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	=Standard Operating Procedure=		=Standard Operating Procedure=
	==Mixing KOH ~~(with~~ pellets)==		==Mixing KOH pellets and etching==
	<div style="background-color: #c0c0c0; border: 1px solid #00000; padding: 10px; border-radius: 5px;">		<div style="background-color: #c0c0c0; border: 1px solid #00000; padding: 10px; border-radius: 5px;">
	* Book the HF fumehood in CR1.		* Book the HF fumehood in CR1.

Harry: /* Mixing KOH (with pellets) */

2026-09-10T13:11:26Z

Mixing KOH (with pellets)

← Older revision		Revision as of 13:11, 10 September 2026
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	** Beakers for measuring and mixing		** Beakers for measuring and mixing
	** KOH pellets		** KOH pellets
	* Set up equipment		* Set up your equipment
	** Fill 2L beaker with water to create a hotbath and add a magnetic stirring pill		** Fill 2L beaker with water to create a hotbath and add a magnetic stirring pill.
	** Balance the scale		** Balance the scale.
	* Calculate the portions of water and solid KOH pellets that you would like to mix:		* Calculate the portions of water and solid KOH pellets that you would like to mix:
	** You are aiming to make a 28% w/w solution		** You are aiming to make a 28% w/w solution
Line 75:		Line 75:
	** The KOH pellets come in units of xxx grams. Start by weighing an appropriate amount of KOH and set it to the side.		** The KOH pellets come in units of xxx grams. Start by weighing an appropriate amount of KOH and set it to the side.
	** Calculate the respective amount of water and fill a beaker with it.		** Calculate the respective amount of water and fill a beaker with it.

	* Slowly add the KOH pellets to the water a few at a time while stirring gently.		* Slowly add the KOH pellets to the water a few at a time while stirring gently.
	* Continue stirring until the pellets dissolve completely		* Continue stirring until the pellets dissolve completely.
	* Place your solution in the hotbath		* Place your solution in the hotbath.
	* Place a second beaker with MQ next to it		* Place a second beaker with MQ next to it.
	* Submerge the probe heater into the MQ beaker		* Submerge the probe heater into the MQ beaker.
	* Start the stirring and set the temperature.		* Start the stirring and set the temperature.
	* Once you reach the desired temperature, you can start etching your sample		* Once you reach the desired temperature, you can start etching your sample.
			*: '''Do not leave the solution unattended.'''
			* Rinse the samples in MQ water.
			* Rinse the samples in a second MQ water.
			* Dry or continue with the rest of your process.
			* Let the KOH solution to cool down to room temperature.
			* Transfer the KOH solution to the '''X-base waste container'''.
			* The MQ water that was used for rinsing can be discarded in the drain.
			* Ensure that all the setup that you used (scale, hotbath, beakers) is back in their original location.
	</div>		</div>

	==Etch rates==		==Etch rates==
	KOH-etching is a highly versatile and cheap way to realize micromechanical structures using Si3N4 or SiO2 masking materials.		KOH-etching is a highly versatile and cheap way to realize micromechanical structures using Si3N4 or SiO2 masking materials.

Harry: /* Standard Operating Procedure */

2026-09-10T12:50:56Z

Standard Operating Procedure

@@ Line 84: / Line 84: @@
 * Once you reach the desired temperature, you can start etching your sample
 </div>
 =First aid measures=

Harry: /* Storage */

2026-09-10T12:50:23Z

Storage

← Older revision		Revision as of 12:50, 10 September 2026
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	==Storage==		==Storage==
	Must be stored tightly sealed in a well-ventilated chemical cabinet. Should not be stored higher than 160 cm due to the risk of corrosion.		Must be stored tightly sealed in a well-ventilated chemical cabinet. Should not be stored higher than 160 cm due to the risk of corrosion.


	==Dangers and Toxicological properties==		==Dangers and Toxicological properties==

Harry: /* Properties and guidelines */

2026-09-10T12:50:16Z

Properties and guidelines

@@ Line 37: / Line 37: @@
 Must be stored tightly sealed in a well-ventilated chemical cabinet. Should not be stored higher than 160 cm due to the risk of corrosion.
-==Chemical properties==
 ==Dangers and Toxicological properties==
 ===Dangers===

Harry: /* Toxicological properties */

2026-09-10T12:41:03Z

Toxicological properties

← Older revision		Revision as of 12:41, 10 September 2026
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	\|-		\|-
	\|}		\|}




	</div>		</div>

Harry: /* Toxicological properties */

2026-09-10T12:40:45Z

Toxicological properties

← Older revision		Revision as of 12:40, 10 September 2026
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	\|}		\|}

	== Toxicological properties==		=== Toxicological properties===
	{\| class="wikitable"		{\| class="wikitable"
	\|-		\|-