solder land analisys

We have been encountering diminishing ball shear readings these past few weeks, despite the fact that we did not change any ball shear tester parameter. Our reflow parameters are also within spec limits. ( 210-220 deg C max temp. and 40-60 sec dwell time ) Beforehand we use to clean the substrates with water (from defluxer), but now we returned to the old procedure of cleaning with acetone. This has promted me to suspect that acetone , someway or the other, effects solderability/wetting. Can I ask your help in the analysis of solder land before and after acetone cleaning ?.

Pkg. Type : CSP-BGA Ball size : 12 & 18 mils

thanks & best regards, nards

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| We have been encountering diminishing ball shear readings these past few weeks, despite the fact that we did not change any ball shear tester parameter. Our reflow parameters are also within spec limits. ( 210-220 deg C max temp. and 40-60 sec dwell time ) Beforehand we use to clean the substrates with water (from defluxer), but now we returned to the old procedure of cleaning with acetone. This has promted me to suspect that acetone , someway or the other, effects solderability/wetting. Can I ask your help in the analysis of solder land before and after acetone cleaning ?. | | Pkg. Type : CSP-BGA | Ball size : 12 & 18 mils | | thanks & best regards, | nards | Acetone is a no no with PCB resin systems of all types. It will smear the resin (epoxy, or?) over the entire board, or the local area you are attempting, including solder termination areas.

Earl Moon

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| | We have been encountering diminishing ball shear readings these past few weeks, despite the fact that we did not change any ball shear tester parameter. Our reflow parameters are also within spec limits. ( 210-220 deg C max temp. and 40-60 sec dwell time ) Beforehand we use to clean the substrates with water (from defluxer), but now we returned to the old procedure of cleaning with acetone. This has promted me to suspect that acetone , someway or the other, effects solderability/wetting. Can I ask your help in the analysis of solder land before and after acetone cleaning ?. | | | | Pkg. Type : CSP-BGA | | Ball size : 12 & 18 mils | | | | thanks & best regards, | | nards | | | Acetone is a no no with PCB resin systems of all types. It will smear the resin (epoxy, or?) over the entire board, or the local area you are attempting, including solder termination areas. | | Earl Moon | Hello Earl,

Is there any existing data or study that shows the effect of acetone over the substrates gold coated solder land, Please help.

..nards

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| | | We have been encountering diminishing ball shear readings these past few weeks, despite the fact that we did not change any ball shear tester parameter. Our reflow parameters are also within spec limits. ( 210-220 deg C max temp. and 40-60 sec dwell time ) Beforehand we use to clean the substrates with water (from defluxer), but now we returned to the old procedure of cleaning with acetone. This has promted me to suspect that acetone , someway or the other, effects solderability/wetting. Can I ask your help in the analysis of solder land before and after acetone cleaning ?. | | | | | | Pkg. Type : CSP-BGA | | | Ball size : 12 & 18 mils | | | | | | thanks & best regards, | | | nards | | | | | Acetone is a no no with PCB resin systems of all types. It will smear the resin (epoxy, or?) over the entire board, or the local area you are attempting, including solder termination areas. | | | | Earl Moon | | | Hello Earl, | | Is there any existing data or study that shows the effect of acetone over the substrates gold coated solder land, Please help. | | ..nards | Nards,

Talk to your local "qualified" board shop and get information concerning best/worst cleaning solvents. If your having difficulty soldering to gold, assuming it's clean, there are other problems possiblt. One is poor electroless deposition processing starting with the copper surface followed by to thin or badly coated nickel, and of course the gold deposition.

All processes associated with gold deposition, and subsequent soldering operations, are critical. If the fabricator does not manage processes well (few really good gold people yet), you will have solderability problems not necessarily a function of cleanliness.

Earl Moon

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