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BGA In-circuit Failure Analysis

Henry Hickey

#15539

BGA In-circuit Failure Analysis | 8 June, 1998

How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can press on the BGA device and the system passes, let go and it fails. I am interested in your thoughts regarding CSAM, Xray, or other, means of inspection. Any recommendations on equipment or methods?

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Earl Moon

#15544

Re: BGA In-circuit Failure Analysis | 8 June, 1998

| How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can press on the BGA device and the system passes, let go and it fails. | I am interested in your thoughts regarding CSAM, Xray, or other, means of | inspection. Any recommendations on equipment or methods? One way is to perform X-Ray first using whatever available to provide clear image. If you don't have hi-res grey scale, use outside NDT lab to have hi-res black and white done. This provides an excellent image (often better than grey scale types) of the entire array and connections. You will see white areas where voids or cracks reside. If you clearly identify them, the next step would be to X-Section likely failures and determine what resides within the cracks or voids. This may be done if you suspect contamination as flux residue remaining to fight oxidation, as an example. SEM/EDX analysis is useful to determine contamination present - as a possible failure mechanism (others may include thermal or mechanical stress/shock) - then you may prevent its recurrance. Earl Moon

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Earl Moon

#15542

Re: BGA In-circuit Failure Analysis | 8 June, 1998

| How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can press on the BGA device and the system passes, let go and it fails. | I am interested in your thoughts regarding CSAM, Xray, or other, means of | inspection. Any recommendations on equipment or methods? Just another thing, If you haven't already, check out the IPC Technet archives for January this year under item 70. Just ran across it looking for other BGA info, Earl Moon

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Mike

#15540

Re: BGA In-circuit Failure Analysis | 8 June, 1998

| How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can press on the BGA device and the system passes, let go and it fails. | I am interested in your thoughts regarding CSAM, Xray, or other, means of | inspection. Any recommendations on equipment or methods? I had a similar problem on a BGA, X-ray showed nothing. So the next step using a dremmel we ground away the component until we reach the top of the BGA Balls, and there was a cracked solder joint. Its a crude method but in this business sometimes crude works. Mike

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Earl Moon

#15541

Re: BGA In-circuit Failure Analysis | 8 June, 1998

| | How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can press on the BGA device and the system passes, let go and it fails. | | I am interested in your thoughts regarding CSAM, Xray, or other, means of | | inspection. Any recommendations on equipment or methods? | I had a similar problem on a BGA, X-ray showed nothing. So the next step using a dremmel we ground away the component until we reach the top of the BGA Balls, and there was a cracked solder joint. Its a crude method but in this business sometimes crude works. | Mike Mike, Great way to go. It's called x-sectioning the hard way but costs a bit less unless you've a bunch and are not making a big salary. Earl Moon

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Bob Willis

#15543

Re: BGA In-circuit Failure Analysis | 16 June, 1998

Simple x-ray inspection works well have a word with those nice people at Nicolet or Glenbrook. One of them was featured on my x-ray training video for BGA. A procedure for inspection criteria is on my web site if it is of use. | | How do I mechanically/visually inspect BGA devices when they are soldered to a PCB for possible solder, or other, defects as a first step before part removal and further analysis? I have had board failures due to poor soldering--I think? I can press on the BGA device and the system passes, let go and it fails. | | I am interested in your thoughts regarding CSAM, Xray, or other, means of | | inspection. Any recommendations on equipment or methods? | Just another thing, | If you haven't already, check out the IPC Technet | archives for January this year under item 70. Just ran across it looking for other BGA info, | Earl Moon

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