Do you use THOU?

shortbus

Joined Sep 30, 2009
10,049
After 50 years as a die maker/machinist it was hard for me to get the concept of 'mil' as a measurement. But guess you have to put things in context of where they are being used, so learned to deal with it. :)
 

Wendy

Joined Mar 24, 2008
23,799
No, I mean the international practice of wirebonding and microelectronics. I've worked in two industries that use it, three if you count the fact that Rockwell International sold its plant to Alcatel. I currently work for Raytheon. The literature is quite clear on this subject, and the wire sizes extremely standardized, as are the machines and many other factors of microelectronics. I looked on wikipedia, their articles are pretty thin on the subject, but the fact is microelectronic manufacturing plant are pretty much everywhere (though not as many as I would like). It is a pretty core high tech industry.

If you had my resume I spent 24 years with Rockwell International (Collins Radio Division), 20 of those years as a Senior Lead Tech, where I interfaced between engineering and production environment. Raytheon gave me a job when I needed one, I operate the machines I used to repair. I've worked there for around 10 years. I have worked in a low level cleanroom environment (class 3, with some sections being higher) for around 30+ years. I have repaired pattern generators used to make ICs, I have maintained the entire process to make microelectronics, starting with the lithographic processes, sputtering machines, diamond saws, high power lasers, bonding machines, and repairing test fixtures. I have worked over a year as a metrology tech calibrating test equipment for the rest of the factory. I've done a lot more than that, but why go on?

You are making the classic mistake of thinking that because you are an expert in your profession, you know others equally well too. In my fields of expertise I am a expert.

The Rockwell Micro Electronics division made several parts for the Space Shuttle, which I worked on. They also had a poster of the inertial navigation tray (a missile disk) for the Redstone missile, which was before my time.

I joined Collins Radio several years after the entire company was sold to Rockwell. Collins in its heyday made Commercial broadcast AM/FM radios, satellite receivers as well as major components for satellites, and many other DOD projects such as TACAMO. It wound up being a telephone equipment manufacture, but the internet changed that landscape totally.

Raytheon is pretty much totally DOD, which means I would prefer not to talk about it at all. I need my job, I like having a job, I just wish I could go back to my old job.

Now you done it. I'm crying in my beer. Real tears too.
 
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THE_RB

Joined Feb 11, 2008
5,438
Damn I hope I didn't come across as critical of you there Bill, it was a genuine question I was asking although admittedly with zero effort spent on politeness or finesse, and on re-reading my post it does sound a bit nasty! Sorry about that.

Thanks for the information on your job at Rockwell, that sounds like one hell of an education not to mention a lot of fun working with some of that technology! :)

Anyway I'll shut up on the subject now. I still think that the term "mil" may be more heavily adopted by engineering in the culture of the USA compared to other western countries but I've made my personal views on the subject pretty clear already and would hate any cultural differences (including cultural or personal preferences for units or terms) to cause any ill feeling between us!

Now I need a beer too! ;)
 

Wendy

Joined Mar 24, 2008
23,799
This reminds me of another discussion about metric vs. imperial. I made the point that feed through semiconductors are 0.1" and are not likely to change, nor are protoboards for pretty much the same reason. It was invented in the USA first, and we got to set the standards, forever. Where metric takes over is with surface mount, but it doesn't really matter there, since the PCB can go either way.

There is no ill will, I know how text comes across sometimes. To be honest, I can discuss wire bonding all day, but not what we do with it. Simple everyday watches are common cheap examples of wire bond, the good stuff uses pure gold for all the components. Commercial stuff uses aluminum wires, and last I heard they were trying to figure out how to use copper. The amount of gold is minuscule, but it adds up. Figure every cruise missile we launched probably had just under an ounce per missile.

The wire bond Collins did (and so does Raytheon) is a alumina ceramic substrate with gold traces and other materials (to make resistors or other components). We glue the raw semiconductors on the substrate with conductive or non conductive epoxies, and uses wires (starting 0.00007", 0.0001", and going up) to connect the raw chips, transistors, capacitors, etc to the golden PCB. The finished components are custom circuits that are only slightly larger than a IC.

If anyone is interested we can start another thread on it sometime.
 
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