<div dir="auto">We have users do this safely in beakers. </div><div dir="auto"><br></div><div dir="auto">Perfectly fine for small pieces (and smaller quantities of chemical).</div><div dir="auto"><br></div><div dir="auto"><div style="font-size:inherit" dir="auto"><span style="font-size:inherit;font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;float:none;display:inline!important;background-color:rgba(0,0,0,0);border-color:rgb(0,0,0);color:rgb(0,0,0)">Certainly not that pleasant for full wafers </span><span style="font-size:inherit;font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;float:none;display:inline!important;background-color:rgba(0,0,0,0);border-color:rgb(0,0,0);color:rgb(0,0,0)">though</span><span style="font-size:inherit;font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;float:none;display:inline!important;background-color:rgba(0,0,0,0);border-color:rgb(0,0,0);color:rgb(0,0,0)"> - once or twice with 4” wafers is </span><span style="font-size:inherit;font-style:normal;font-weight:400;letter-spacing:normal;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration:none;float:none;display:inline!important;background-color:rgba(0,0,0,0);border-color:rgb(0,0,0);color:rgb(0,0,0)">fine, but very few decide to do this 10 times without a better setup. </span></div><br clear="all"><div dir="auto"><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><font face="georgia, serif" size="4" style="font-family:georgia,serif;color:rgb(0,0,0)">-- Demis </font><font face="georgia, serif" size="1" style="font-family:georgia,serif;color:rgb(0,0,0)">(<a href="https://wiki.nanotech.ucsb.edu/wiki/Demis_D._John" target="_blank" style="font-family:georgia,serif">contact info</a>)</font><div><i style="font-family:"times new roman",serif">Reminder</i><span style="font-family:"times new roman",serif">: The NanoFab has a </span><a href="https://wiki.nanotech.ucsb.edu/wiki/Frequently_Asked_Questions#Publications_acknowledging_the_Nanofab" style="font-family:"times new roman",serif" target="_blank">publications policy</a><font face="georgia, serif" size="4" style="font-family:georgia,serif;color:rgb(0,0,0)"><br></font></div></div></div></div></div><div><br></div><div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Mon, Apr 20, 2026 at 18:55 Nathanael Sieb <<a href="mailto:sieb@4dlabs.ca">sieb@4dlabs.ca</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
<div>
<p>Hi Lorenzo,</p>
<p>Thanks for your detailed feedback and this was along the lines of
my expectations. Have you or anyone else seen any self-contained
table-top baths that would fit on top of a wet-bench deck? Most
of what I've seen is deck-mount in a wet bench or a heater-chiller
designed to heat or cool a bath but not contain chemicals.</p>
<p>Does anyone do this safely without using an acid bath permanently
built into a wet bench? I'm guessing the answer is mainly no, but
I figured I'd check.</p>
<p>Thanks,</p>
<p>Nathanael</p></div><div>
<p><br>
</p>
<div>On 2026-04-19 9:35 a.m., Lorenzo
Palmiano wrote:<br>
</div>
<blockquote type="cite">
Here are some tips, OSHA and SDS also breaks down all the safety
pre-cautions is 5 parts: engineering, handling, storage, PPE and
emergency response.
<div><br>
</div>
<div>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
At ~160 °C, phosphoric acid is highly viscous and near
boiling. Risks include increased splashing and bumping, higher
aerosol or acid mist generation, and severe combined thermal
and chemical burns from any contact.</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">1. Equipment and Temperature
Control</span><br>
• Use only a temperature‑controlled acid bath or certified wet
etch bench<br>
• Do not use open beakers on generic hot plates<br>
• Verify bath temperature with an independent thermometer or
probe<br>
• Avoid overshoot above setpoint; local overheating increases
instability<br>
• Never leave heating unattended</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">2. Water Exclusion (Zero
Tolerance)</span><br>
• Absolutely no DI water near the bath while hot<br>
• No wet wafers, tools, or condensation introduction<br>
• Do not add water to hot acid under any circumstances<br>
• Any water contact at this temperature can cause violent
splattering</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">3. Required PPE at ≥160 °C</span><br>
• Chemical splash goggles AND full face shield (both required)<br>
• Acid‑resistant apron (front facing out)<br>
• Long acid‑resistant gloves with arm shields<br>
• Standard safety glasses alone are not sufficient<br>
• Do not use stained, wet, cracked, or poorly fitting PPE</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">4. Positioning and Handling
Discipline</span><br>
• Never lean over the bath<br>
• Approach from the side, not directly from the front<br>
• Move slowly to avoid wave‑induced splashing<br>
• Treat all clear liquids as hot acid — never assume it is
water</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">5. Ventilation and Airflow</span><br>
• Operate only with confirmed functioning exhaust<br>
• If airflow or power is lost, stop work immediately and leave
the area<br>
• Hot phosphoric acid fumes and mist present inhalation
hazards</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">6. Emergency Readiness
(Before Starting)</span><br>
• Know the exact location of the eyewash and safety shower<br>
• Be prepared to cut heater power immediately if needed<br>
• In case of skin or eye exposure, flush with water for at
least 15 minutes and seek medical attention</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
<span style="font-weight:bold;font-family:system-ui">Bottom Line</span><br>
At ~160 °C, hot phosphoric acid must be treated as
near‑boiling corrosive material. Strict temperature control,
zero water exposure, full PPE, proper ventilation, and
disciplined handling are mandatory.</p>
<p style="margin:0px 0px 12px;font-style:normal;font-variant-caps:normal;line-height:normal;font-family:system-ui;font-size-adjust:none;font-kerning:auto;font-variant-alternates:normal;font-variant-ligatures:normal;font-variant-numeric:normal;font-variant-east-asian:normal;font-feature-settings:normal">
Please follow these precautions without exception.</p>
</div>
<div><br id="m_-9091819927630100658lineBreakAtBeginningOfSignature">
<div dir="ltr">Lorenzo P
<div>415.404.0565</div>
<div><a href="http://www.espie-electronic.com" target="_blank">www.espie-electronic.com</a></div>
</div>
<div dir="ltr"><br>
<blockquote type="cite">On Apr 19, 2026, at 7:23 AM, Nathanael
Sieb <a href="mailto:sieb@4dlabs.ca" target="_blank"><sieb@4dlabs.ca></a> wrote:<br>
<br>
</blockquote>
</div>
<blockquote type="cite">
<div dir="ltr">hot phosphoric acid etching in your facilities,
I would appreciate any safety or operational tips you have.
For us it would need to be a hot-plate process, and I want
to make sure we are taking a cautious approach before
allowing heating of phosphoric up to 160°C.</div>
</blockquote>
</div>
</blockquote>
</div><div><div>
<div id="m_-9091819927630100658Signature">
<p style="font-family:Arial,Helvetica,sans-serif;font-size:13.3333px"> <b style="font-family:Calibri,Helvetica,sans-serif;font-size:16px"> <span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt">Nathanael
Sieb</span> </b> <br style="font-family:Calibri,Helvetica,sans-serif;font-size:16px">
<span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt"><span style="font-size:10pt;font-family:Arial,Helvetica,sans-serif">Director of Operations and
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<br style="font-family:Calibri,Helvetica,sans-serif;font-size:16px">
<span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt">Simon
Fraser University</span> <br style="font-family:Calibri,Helvetica,sans-serif;font-size:16px">
<span style="font-family:Arial,Helvetica,sans-serif;font-size:10pt"><a href="https://www.google.com/maps/search/8888%0D%0A++++++++++++++University+Dr.,+Burnaby,+B.C.+V5A+1S6?entry=gmail&source=g" style="font-family:Arial,Helvetica,sans-serif">8888
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