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BGA inspection scope - Visual

We have been looking around at all of the various BGA visual... - Jun 11, 2003 by T2  


T2

#24771

BGA inspection scope - Visual | 11 June, 2003

We have been looking around at all of the various BGA visual inspection systems, (i.e. ERSAscopes like contraptions). It seems like the number of different manufacturer's of these types of systems has exploded in the past couple of years, and it looks to be a lot of re-branding of equipment. Does anybody have any experiences with this type or equipment? We are looking for first hand experiences, (i.e. the good, the bad, and the ugly), not sales pitches......

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Stephen

#24778

BGA inspection scope - Visual | 11 June, 2003

We looked at some systems but didn't buy any. What we use is a little mirror. I believe Metron makes it. It is a small diamond shaped mirror with beveled sides and a handle. Used with a microscope, you can see a lot. They are around $100.00. Sometimes low tech is best.

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RDR

#24779

BGA inspection scope - Visual | 11 June, 2003

I am in agreement with Stephen. we also use the little mirror with a microscope.

Russ

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Steve

#24788

BGA inspection scope - Visual | 11 June, 2003

Do you happen to know where I may find a supplier for the "little mirror"? Google didn't produce relevant search results for Mentor. My method of inspecting possible bridging under a BGA involved a small flashlight placed up against the edge of the PCB while visually checking for the light to pass through on the opposite side of the component. Needless to say, your method seems more effective. Would appreciate your help.

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#24794

BGA inspection scope - Visual | 12 June, 2003

Most of the tools that are available in the market eg.ERSAscope or something similar gives a fair idea about the outside rows only and in case the defect happens in the inner layers all these tools are useless.The best way is to use AXI but then its not cost viable.

Sanjeev

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Steven

#24804

BGA inspection scope - Visual | 12 June, 2003

The last statement saying that seeing down the bga component with these systems is useless, is an incorrect statement. First with x-ray you do not see flux residue and or flux migration, second with x-ray you do not see a cold solder joint. Visual inspection far exceeds what any other method. I have had experience with many of these systems. Draw backs have been A) poor lighting B) if you have a staggard array component then the light source will not shine thru thus balls in the center of the package are difficult to see. Standard array packages are fine for these systems. C) Lens scratch costs an arm and a leg for repair and it happens often D)A highly populated dense package board sometimes it is difficult to get the lens down in close enough to be able to see the package. E) Angle vision is out except for one system and I'm not here to promote any one system D) Service must be a concern. my suggestion is deal with a vendor who has sold enough systems that they know the in's and out's and are there to service you at a drop of a dime. As far the the Metron mirrors are concerned, we used alot of them prior to purchasing a bga inspection system. We got these from a distributor in NewHampshire. Hope this was of help to you.

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CAL

#24808

BGA inspection scope - Visual | 12 June, 2003

Edmunds Optics has them

http://www.edmundoptics.com/IOD/DisplayProduct.cfm?productid=2038

the link above is for a Prism. Works well. Continued search on the Edmunds site will get you a mirror if need be.

Cal Communications Test Design, Inc www.CTDI.com

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RDR

#24816

BGA inspection scope - Visual | 12 June, 2003

The supplier is METRON

We use model M90-S

Website http://www.metronusa.com phone - 858-755-4477

Russ

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Larry D

#24879

BGA inspection scope - Visual | 18 June, 2003

Tom:

Cheapest is grind flat spot on inspection mirror. Plastic mirror is easiest and works for the 1st 2 rows.

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Eric QE

#24889

BGA inspection scope - Visual | 19 June, 2003

Caltex or Ersa type system is good, Caltex prisms, necessary for looking underneath the BGA can be crashed easily when looking under low profile or Micros. $40-$110 each depending on the availability and who makes 'em. We have 2D and 3D X-ray available, but a visual, with the ability to send and save a blow up picture of a BGA joint is necessary for optimizing profiles and pointing out Warp and Flux and cold solder issues. 99% we are looking at outside and corner balls. For me, I like that new hand held system. Don't have one yet. Any feedback on that from anyone.

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derelict

#24892

BGA inspection scope - Visual | 19 June, 2003

I am pretty happy with my Ersascope, they have been a little slow with software updates and with software questions that i have had. But my main reason that this has paid for itself is dealing with our non-local contract manufacturers, we have used the mirrors for years and that is fine if the same operator is going to do the rework and reinspection of lets say a BGA for instance. But if you have to send the board back across the country and explain what you saw using the mirror, verses sending pictures taken by the ersascope. One limitation of the ersascope is the room it requires between components.

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Steve

#24894

BGA inspection scope - Visual | 19 June, 2003

So how much clearance between components (in mm) does the Ersascope require? What if you have caps around (2-3mm from the BGA's edge) a BGA . . . is it necessary to remove them prior to inspection of the BGA?

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#24899

BGA inspection scope - Visual | 19 June, 2003

I like you looked all over and was frustrated. The prices that they are asking, you would think that we were back in the 90s when money was all over the place.

After looking around I found a BGA-100 from SMT Tools. This system will do everything you will need for under 4k. My techs and customers have been impressed with the images especially with the color pictures from the printer he offers.

Buy the way, with the $20k i saved we bought a x-ray system to go with it.

Gary

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blundell

#24901

BGA inspection scope - Visual | 19 June, 2003

We can speak from experience, the Ersascope needs only 1.5mm to see along side a device and is the only system that looks low enough, the cheaper systems may be fine for normal packages but forget it for csp's, micro BGA's Also its the only system that you can put the lense up against the package and still see. Further to this it now has a lense protection system which has stopped all breakages.

Sorry I'm a convert The Ersascope seems to be the Industry standard, all the other systems have jumped on the band wagon but don't offer the same advancements ie magnification for a start.

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#24902

BGA inspection scope - Visual | 19 June, 2003

Mini Micro Stencil sells a mirror for $40.00. This thing is great and is made from metal so it won't break so easy. It is also only .008" thick. minimicrostencil.com

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Pete

#24915

BGA inspection scope - Visual | 20 June, 2003

Why all the fuss about BGA inspection?? If your reflow process is sound and your rework system is competent (i.e a PDR) they will be fine. Best advice I can offer is to srike a deal with an outside company who will inspect a small batch of your products every 4-6 months with there X-RAY own X-RAY systems looking for voids and other problems. You will probably find they have spent a fortune on X-RAY and hardly use it, They will do almost anything to get this equipment paid for.

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blundell

#24918

BGA inspection scope - Visual | 20 June, 2003

This is a very narrow view you have, X-Ray does not see all the problems that can occur, even with good rework gear or a sound reflow process it is still possible to get soldering defects, how do you know if you have a sound process to begin with if you don't inspect correctly, ie visual and xray.They compliment each other.

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Paul Cooper

#24925

BGA inspection scope - Visual | 23 June, 2003

Hi there There are a number of things worth considering when viewing bga's. Firstly, like any other solder joint that you have been inspecting for years, suface finish is critical. Secondly, and again like other joints shape is important. Now it may not look like any other solder joint but it has its own signature and depending on pad configuration will be distinctive. So the the shape will confirm a double drop and surface finish, bright and shiny in the case of tin-lead (lead-free surface finish will depend on the lead replacement element)will connfirm the correct reflow period.(too short - dull and potentially single drop, no long term reliability. too long - grainy, overexposed, excess bond material potential tin lead seperation) Once you have confirmed shape and surface finish around the perimeter with the Ersascope, you simply adjust, with the focus ring, the focal distance and compare the profile of the other joint behind. If there is any deviation in process across the bga this profile will highlight the problem. ie what we have see regularly is where the outer solder balls have reflowed correctly but the center cluster, usually down to a ground plane, have not fully reflowed to the pads. In this case instead of the uniform pattern that the outer ball demonstrate you can see a totally different shape to the profile of the center balls. Now on a standard 1mm pitch 25mm square device you can see all the way through, any larger or finer pitched would require viewing from all four sides to confirm your initial reflow profile. However after that, as long as you can get to four or five places around the device to confirm shape and finish you can be confident that your process is under control. In addition you can measure very accutrately with the Ersascope certainly to within 10�m though the manufacturers will tell you 1�m. Either way it is a very quick way to confirm your double drop. On a typical 225 device single drop (No intermetalic bond but full electrical contact) = 0.550mm �0.01mm - Double drop (full intermetalic bond and reliable long term joint) = 0.460mm �0.01mm. Hope this is of assistance, if there is anything else I can help with or contribute to please feel free to cantact me at any time. Best of luck Paul C

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Rex G

#25026

BGA inspection scope - Visual | 1 July, 2003

I agree with the idea of having an outside company look at these parts. How can I find out who offers this type of service?

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CAL

#25027

BGA inspection scope - Visual | 1 July, 2003

REX- Contact ACI 610-362-1200 x224. The contact person is Mr. Jeff Stong. They are cheap and will give you a report. www.aciusa.org jstong@aciusa.org

There are some other labs that do this...but we use this one as it is close to us and they do a descent job.

Cal Communications Test Design, Inc.

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