Hi Pat,

        It's good to hear from you and to see you are right on top of this
technet bulliten board. Yes, I do mean The Chlorate, it's a better oxidizer due
to the additional oxygen on the molecule. From the explosive nature standpoint,
it is used in the making of match heads or its coralary Potassium Chlorate,
which is even more percussion sensitive. Several other companies have used this
system with NaCl in lieu of the HCl.

Thanks for the Question,

Les Connally
[log in to unmask]


>  From: "Goldman, Patricia J." <[log in to unmask]>, on 10/23/97 12:05 PM:
>  Les,
>
>  Are you sure you don't mean Sodium Chlorite, with an "i"?
>
>  Patty
>   ----------
>  From: Leslie O. Connally
>  To: TechNet
>  Subject: Re: [TN] [TECHNET] Cupric Chloride Etchant
>  Date: Thursday, October 23, 1997 8:57AM
>
>  <<File Attachment: ATTRIBS.BND>>
>
>   Hi Jack,
>
>          Im sure by now you have received many opinions on the Cupric etch &
>  regeneration schemes, but I must put in my two cents worth. I have utilized
>  both the HCl/Peroxide and the Sodium Chlorate/HCl systems. I worked
>  extensively
>  with the Peroxide system at TI, in both the etching and the regeneration
>  system. We utilized the Venturi Injection system, mentioned by others for
>  injecting the peroxide, but found, for our system, that the timing sequence
>  would not allow enough HCl to be injected. We, therefore injected the HCl
>  directly into the sump. We controlled the Normality of the HCl with a
>  Rosemount
>  Conductivity controller and the Oxidation Potential with an ORP
>  sensor/controller. The ORP must be controlled within a certain range to
>  prevent
>  Cl gas from evolving as well as obtaining a stable etch rate. To me this was
>  the better system. While working at Sandia Natl Labs, we utilized the Sodium
>  chlorate system. I was informed by Steve Wall at Chemcut ( now Ato-tech)
>  that
>  the Sodium Chlorate/NaCl system might wear on the nozzles more than the
>  other
>  system. The only explanition I can come up with for the increased wear would
>  be
>  that there might be some undisolved solids present. At Sandia, the shop was
>  smalland could not afford the extensive piping for the plumbed HCl and
>  Peroxide, therefore the choice to utilize Sodium Chlorate was taken. We
>  utilized HCl in lieu of the NaCl to avoid undisolved solids and wear on the
>  nozzles. The control was much the same as that at TI and the system worked
>  very
>  well. A word of caution about Sodium Chlorate, is that as the Dry salt it is
>  percussion sensitive, being a strong oxidizer, it can detonate on jarring or
>  pressure ( if it is in conjunction with flammables watch out). This is not a
>  problem when it is in solution. In the small shop at Sandia, both the
>  Chlorate
>  and the HCl were Injected into the sump, from small drums via positive
>  displacement pumps. An excellent resource for the Cupric System is Don Ball
>  of
>  Chemcut (now Ato-Tech). I'm not sure he is still with them. He has written
>  numerous articles on the system. In no way would I try the CL regeneration
>  system, the risk is just too great in my opinion. If I can be of further
>  assistance you might want to contact me off line.
>
>  Good luck,
>
>  Les Connally
>  [log in to unmask]
>
>
>  >  From: Jack Evans <[log in to unmask]>, on 10/21/97 10:12 AM:
>  >  Good Morning Everyone,
>  >
>  >  We are in the process building a new inner layer facility and are
>  >  considering using Cupric Chloride etchant. Does anyone out their have
>  >  any suggestion on the safest, cleanest way to control the process ?
>  >
>  >  Any suggestions would be appreciated.
>  >
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