[labnetwork] Pyrogenic internal torch

Wed Aug 4 14:52:08 EDT 2021

Here is what you should be using anyway. Most of the wetox processes from wafer producers use this technology.

Fatsr, more uniform growth. Safer, etc.

Thank you,

Keith F. Barnes
Sales Representative

SEMITORR GROUP, INC.
High Purity, Sanitary, Industrial Divisions

1951 Rutan Drive
Livermore, CA  94551
tel:   925.667.3607
cell:  925.337.2221
email:  kbarnes at semitorrinc.com<mailto:kbarnes at semitorrinc.com>
web:  www.semitorrinc.com
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From: labnetwork [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of mark cooper
Sent: Tuesday, August 3, 2021 8:36 PM
To: Paolini, Steven; Scott Blondell; labnetwork at mtl.mit.edu
Subject: Re: [labnetwork] Pyrogenic internal torch

Back in the day Bruce, Thermco, MRL and Persys all had multiple versions of the external torch hardware, and some were integrated well, and some were clunky.

The original J hook actually had the flame active in the source zone and could create 10 degree shift in the temperature as the flame tickled the back of the tube. The external torch designs cut down the source zone delta t to a degree or less in process conditions. Huge improvement. J hook had reliability issues with the flame and flow patterns, small flow changes effected the flame direction and quality.

You need to maintain your flow ratio of H2 O2 to 1.88 or less, and most of the torches will allow you to wait 10 seconds to see the flame after gasses flow.

The MRL and the Thermco style both use a reliable Honeywell uv sensor for flame sense, pretty reliable.

MRL designs have a jacket around the torch to help manage heat. Persys use a lot of CDA to cool the torch, and Thermco design requires a scavenger to pull the excess heat out of the source cabinet. Thermco did make a water cooled unit that was pretty fancy, and wasnt used often.

Bruce had its own design, and migrated to a version of the persys torch hardware with its 5600 model external torch control system

Persys uses lamps technology to light the flame, and once the flame is set, the lamps turn off.

If your furnace is profiled, it should be able to obtain 1% or 2 % process uniformity using the external torch designs.

Expertech does have product knowledge across all of the versions, and can help guide you. Feel free to reach out directly and we can get you back on track. We do offer new, remanufactured, and subject to availability used working parts. I cant say we support every torch perturbation from in 40 years but we are qualified historians and know the evolution.

thanks

Mark Cooper

General Manager

10 Victor Square, Suite 100

Scotts Valley, CA.  95066

Office: (831) 439-9300

Direct:(831) 440-4422

Mobile:(831) 332-9396

markc at exper-tech.com<mailto:markc at exper-tech.com>

________________________________
From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Paolini, Steven <spaolini at cns.fas.harvard.edu>
Sent: 03 August 2021 14:00
To: Scott Blondell <spb1699 at rit.edu>; labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
Subject: Re: [labnetwork] Pyrogenic internal torch

Scott,

  Over the years, I have had great results with MRL external torches. The main advantage is being able to see the combustion and whether or not the torch depth is correct. The other big advantage is being able to use a flame detector that will shut off the H2 flow in a couple of seconds (adjustable) to avoid injecting  gas continuously into a cold torch. You may be seeing uniformity issues with the coaxial if you have tiny air leaks being pulled into the tube from the ground glass joints. Are you using Teflon seals? In any event, please ensure that you are running the H2/O2 mix Oxygen rich to prevent accumulating H2 downstream.

  Equipment Dood

Steve Paolini

Principal Equipment Engineer

Harvard University Center for Nanoscale Systems

11 Oxford St.

Cambridge, MA 02138

617- 496- 9816

spaolini at cns.fas.harvard.edu

https://link.edgepilot.com/s/b7b03dc8/ZCMBBvoxO0m0LqkUTi5CxA?u=http://www.cns.fas.harvard.edu/

From: labnetwork <labnetwork-bounces at mtl.mit.edu> On Behalf Of Scott Blondell
Sent: Tuesday, August 03, 2021 3:50 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] Pyrogenic internal torch

Greetings Labnetters,

We're in the process of tweaking our wet ox process. Hardware changes provided an opportunity to consider

alternatives to our current internal "candy cane" torch arrangement employed in several tubes. Currently running 6" silicon

in 205/211mm quartz w/candy cane torch. This doesn't give us the luxury of a simple visual inspection without pulling the tube.

A straight coaxial torch is being qualified now, and it's presenting some challenges. Growth rates are lower than predicted and

across boat uniform is >6%.

Polling the audience: what are your preferences - cane v straight?; straight torch design details/vendors?; gas flows?

There's a lot of knobs to turn - at 2/runs per day it's slow to fine tune.

We do have an MRL external torch that served us well for lower temp processes. Space and budget precludes using it in

multiple tubes.

Appreciate any feedback, tips or outright opinions.

Regards,

Scott P. Blondell

Fac. Mgr.

RIT SMFL

315.738.4073

Expert Semiconductor Technology, Inc.

Phone: (831) 439-9300

Fax: (831) 439-8139

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mark cooper

Expert Semiconductor Technology, Inc.

Phone: (831) 439-9300

Fax: (831) 439-8139

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