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Rambuss

Kathy Palumbo

#4054

Rambuss | 18 May, 2000

Is there anyone out there building Rambuss modules? We have been building Rambuss modules using Samsung IC's and are currently experiencing a 50% failure rate. We build the same modules with other IC suppliers and we have a 100% yeild. Is there anyone else experiencing a similar problem that would be willing to share some technical data? I would like to join forces so we can get Samsung to help in resolving the issues we are having. Please contact me if you can.

Thanks, Kathy Palumbo

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Earl Moon

#4055

Re: Rambuss | 20 May, 2000

Kathy,

I couldn't not get involved here. A question of particular interest not in the normal vein or type. Wow!

Good to see from you again even on the SMTnet. I still appreciate the help you gave on the DEK Proflo issue about two years ago.

I just finished a contract with Cray through Celestica. My compadres there were designing in a lot of RAMBUS. At the outset there were problems with all chip types - among them Samsung. We just attributed the failures to thermal issues as the stuff gets very hot, as you know. However, cooling is a thing Cray is very good at effecting.

I can check with some of my friends still there and see if any partucular brand stood out. My reason for interest is because of the experience just stated with many more to come in a new contract I am just starting.

You might also prod Mike B., the new kid, on the forum. I believe he now employs it and is a QA Manager to boot.

Sorry Mike but, at least, you didn't say anything confidential. Hope I didn't either.

Earl Moon

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Michael Parker

#4056

Re: Rambus | 22 May, 2000

Earl- In the immortal words of Orson Welles- I will spill no wine before its time. We are both safe here. Actually, I was contacted by Kathy via a paste supplier. I suggested to Kathy that we use this forum to air the issues and get multi-perspectives from the community at large.

Kathy, so far I have experienced greater yields with Samsung devices. > 80%. There are too many factors at hand to point the finger yet. We need to build a truth table and dot the i's and cross the t's before stepping up to Goliath (Samsung). Is you placement guranteed good? What x-ray have you used? Are your fab.'s known good? Could you de-solder Samsung and replace with another onto the same fab. and get a runner?

How about profile? Are you marginal and getting cold joints? Watch it DaveF, this is not a reference to those thrilling days of yesteryear. The Valkeries still ride hard to the Inferno!!!!!!!!

To all, Rambus is the promotion of the future in memory. Better than Gingko and Viagra combined. Join in the fray, add your 2 cents worth and be proud of helping your compadres through the birthing pains.

Michael Parker

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Kathy Palumbo

#4057

Re: Rambus | 22 May, 2000

Mike,

Is that greater than 80% yeilds, or less than? Here are the answers to your questions: Is you placement guranteed good? YES What x-ray have you used? Nicolet Are your fab.'s known good? YES Could you de-solder Samsung and replace with another onto the same fab. and get a runner? Even one step further than this. Desolder a known good IC off a passing module. Re-ball the part and place it on a failing module part and get it to pass. How about profile? Good Are you marginal and getting cold joints? NO. We get a 100% yeild when building with any other IC supplier.

We did get a failure analysis report from Samsung telling us that an ECO that was issued in December caused BIOS operating issues and had to re-tracted. Any IC with a data code of 2/2000 will have chances of having issues.

Thanks, Kathy Palumbo

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Michael Parker

#4058

Re: Rambus | 23 May, 2000

Kathy- Greater than 88%. Is that 3-D Nicolet?

I had a conversation with Arline yesterday, she told me about your trials and tribulations with re-balling. I would like to suggest you try micro-stencil instead. If your BGA rework center has the capability to de-solder, then clear off the remaining solder bumps from the back side of the chip, micro-stencil all new with paste and reflow. This may not speed up the process but will certainly reduce the frustration levels of the people having to chase such small objects with tweezers.

I will have my Design guys contact Samsung. We have a good working relationship with Samsung. They too produce modules. Maybe they can share some of their wisdom. This ECO with BIOS issues may be something. My chips are datecode 10 and 13. Have you updated your BIOS on your test motherboard to latest of Intel?

By the way, do you also have Toshiba chips. This causes me the most failures so far.

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#4059

Re: Rambuss | 23 May, 2000

Kathy: Our RAMBUS are from last year. We are seeing 98+ yield. Sorry, we're no help. Dave F

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