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Ted Mooney, P.E. RET
Pine Beach, NJ

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XRF coating thickness measurements -calibration for thin gold

1998

Q. I am interested in accurate XRF coating thickness measurements for AU/NI/CU in the range 0,07-0,35 micrometers AU and 1,5-5 micrometers NI. My XRF measuring system is calibrated with samples beginning with 0,45 micrometers AU.What standards should I order to get accurate readings? What is the influence of the plating method? How should I write the part specification in order to get a good correlation between my measurements and the supplier's measurements?

Thank you for the opportunity to address this forum.

gaby

Gabriela B [last name deleted for privacy by Editor]

A. Gaby,
These are extremely thin Au surfaces and quite thin Ni. But it sounds do-able. Most XRF standards are foils that are glued into the handlers, but your thicknesses may be too thin. One of the XRF standards suppliers will custom make you a standard set. It's not so expensive. Just call them and discuss your concerns. They are very helpful. More important than the thickness will be the length and width of the surface to be analyzed. Circles of less that 3 mils diameter require special collimators to be special ordered. When you talk to the manufacturer, be sure to completely describe the substrate, as it can interfere. You can send the supplier a sample as well...and let them figure it out. After all, what do you pay them for anyway?

Regards,
Dave

Dave Kinghorn
Chemical Engineer
SUNNYvale, California
1997

Who are the XRF manufacturers for Thickness measurement?

BC Chan
Sdn Bhd - Malaysia
2000

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Ed. note: Please see our Directory of Test Equipment for thickness measurement devices.
Our supporting advertisers generously make this site possible for camaraderie and technical discussions; sorry, but it wouldn't be fair for us to spend their money steering potential customers to their competitors.

While it is commendable to support the site sponsors, do you feel supporting your readers with complete information would be beneficial to them? Eastern Applied Research, for example, offers new and USED XRF analyzers for thickness -- that may be a benefit to the readers.

S. Kramer
Eastern Applied Research - Lockport, New York USA
February 17, 2011

Hi, S. It would be beneficial to some of our readers if their police department would serve them breakfast in bed :-)
-- but every service has its function & its limitations. This site is for technical info exchange & camaraderie, not for maintaining contact info for commercial sources. It's not just about limiting solicitations to advertisements, it's also that competing claims have proven to hurt that spirit of camaraderie, and lead to unmanageable spam.

Still, we'll give your way a try: Please go ahead and advise Mr. Chan of the names of several XRF suppliers servicing Malaysia so he has the complete information you say he needs. Chinese suppliers are probably less expensive, so please include at least one of them. Thanks!

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 17, 2011

Cost comparison for XRF standards

Q. I am sourcing for a 0.05 µm AU standard foil for XRF machine calibration.
So far found 2 quotes: 1st quote at USD 500 per unit, 2nd quote at USD 1.5k per unit (3 times more expensive than the first quote).

Appreciate if anyone could advise me:
1. Why the price of standard foil (with same thickness) could differ in such a big price range?

2. How are these standard foils calibrated during manufacturing? The cost difference is caused by the manufacturing method or calibration method?

Thank you.

Ivy Lim
FPCB finishing engineering - Melaka, Malaysia
December 23, 2014

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Ed. note: per discussion above, please don't suggest vendors unless you suggest several.

A. Hello Ivy,
With my experience in using XRF machines and having to order new thickness standards, I don't recall them being that expensive (500-1500 USD). There are suppliers that have used standards available and come with certifications. I have been told the standards are mfg by vacuum metallization deposition to the thickness range desired. The standard is not really calibrated per say, the standard is calibrated to the machine when you receive it. I did notice that the thinner the gold thickness standard was, the more it costs. We had 2 standards for gold. One for hard gold, one for immersion gold. The immersion gold standard was more expensive. The cost is also dictated by the plating underneath the gold (Ni, Pd, etc). We also noticed that the thinner the plated gold deposit measured on our XRF, the higher the margin of error was in the readings. Our thickness range was 3 - 5u" for immersion gold. Anything below 2u" did not give us accurate readings on the XRF. I would do some more research on the standard and get more quotes.

Mark Baker
Process Engineer - Phoenix, Arizona USA
December 26, 2014

A. Hi Ivy,
1. Depending on manufacturers, there may be some price difference. The standard calibration foil that I am getting here costs me about US500.00
2. Your XRF machine has a calibration column, click on it and just follow the instructions. Get tech support from your XRF supplier, they are more than willing to help.

SK Cheah
- Penang Malaysia
December 26, 2014

December 28, 2014

A. Hi Ivy Lim,

That is always difficult to find out. There can be a number of reasons for this, ranging from "better quality (assurance)" to "higher profit margins".

A standard is something which needs a very precise manufacturing process and well defined checks. You can buy them from companies that just started and manufacture them in their garage (and these companies can be good) to companies that are well established in the market, have a large well equipped laboratory and have for sure higher overhead costs.

Imagine your .05µ standard is .055µ in reality. That means that over the years you continuously give away 10% on your Gold. I wouldn't mind if I had to pay more IF one of the two suppliers guarantees the actual thickness range via more reliable (costlier?) methods. The only way to find it out is to ask questions to both suppliers. What is the range in which they deliver that .05µ standard? How do they make sure that they achieved the right thickness and how do they know that?

In order to answer your question for specific suppliers, you should buy both and compare them (if you can bear the costs).

You probably want to share the results of your calibration with your customers equipment as well. Sometimes you'll be surprised about the differences that can occur.

Best Regards,

Harry van der Zanden
consultant - Tilburg, Netherlands

Q. Hello Mark, Cheah & Harry,

Appreciate your response to my inquiry!

Both quotes were provided by the manufacturer's regional sales representative in Malaysia, standard foil in 1st quote (with cheaper price) will be manufactured in Korea and the foil in 2nd quote will be manufactured in Germany. Both manufacturers shall provide a certificate of compliance for the foil which is valid for 1 year only. For continuous use in subsequent years, I need to pay (again, big difference in the cost quote by the two manufacturers), and resend to the original manufacturer to revalidate the foil thickness. Assuming I purchased both foils and want to do re-validation, both manufacturers are not agreeing to do for their competitor's foil. Hence, kindly share your opinion:
1. Is it a "must" to send the foil for manufacturer revalidation on yearly basis. Do you practice this for your foils? If I didn't do it, am I violating ISO 9001 compliance?

2. Without using my XRF machine, is there any external laboratory which could do the foil thickness validation without concerning the foil's origin manufacturer? So that I could send both foils to this neutral laboratory for a fair thickness comparison?

Thank you.

Ivy Lim [returning]
- Melaka, Malaysia
December 28, 2014

A. Hello again Ivy,
It is probably mandated by the certification your company holds to have the standards verified on an annual basis. I am not sure of the verification frequency, but it will be in your documents. It is not necessary that you send the standards back to the mfg. There are independent labs that specialize in calibration / thickness measuring verifications. Insist that they send you certs upon shipping them back to you. The reason the mfg wants you to use them for the verifications is because they are in business to make more money. The standards come in a protective case and must be kept in those cases. I have seen them just lying around the XRF machine with scratches and worn down. Hope this helps and have a Happy New Year!

Mark Baker
Process Engineer - Phoenix, Arizona USA
December 30, 2014

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