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SOLDER BALL UNDER THE PCB AFTER REFLOW SOLDERING

PARK KYUNG SAM

#14004

SOLDER BALL UNDER THE PCB AFTER REFLOW SOLDERING | 1 October, 1998

Are there anyone who can give me the answer about solder ball problem? We have 12 layer PCB and double sided PCB. After one side reflow soldering We found lots of solder ball under the PCB. The solder ball was coming out from via hole. So when we print the other side , there are lots of bridge because of solder ball. PCB MAKER said we can not get rid of melted solder in the via hole during HAL process. Is it true or not. Do I have to make things to remove solderball under PCB automatically after one side soldering. I NEED YOUR EXPERIENCE.

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Justin Medernach

#14005

Re: SOLDER BALL UNDER THE PCB AFTER REFLOW SOLDERING | 1 October, 1998

Are there anyone who can give me the answer about solder ball problem? | We have 12 layer PCB and double sided PCB. After one side reflow soldering We found lots of solder ball under the PCB. The solder ball was coming out from via hole. | So when we print the other side , there are lots of bridge | because of solder ball. | PCB MAKER said we can not get rid of melted solder in the via hole during HAL process. | Is it true or not. | Do I have to make things to remove solderball under PCB automatically after one side soldering. | I NEED YOUR EXPERIENCE. Kyung Sam, It is the fault of your PCB manufacturer or your designer. they are getting solder in the vias in their process. When you send the substrate through reflow, the solder falls out. Tenting the vias is an option on the next spin. Justin

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Paul R. Smith

#14006

Re: SOLDER BALL UNDER THE PCB AFTER REFLOW SOLDERING | 1 October, 1998

Kyung Sam, Justin is correct, there is definately either a board design problem or the PCB maker issue. Obviously there are many mixed technology boards built in the world so I would lean towards a design issue as the root cause. Should you or your PCB house not be able to come up with a solution, there is a machine designed to remove solder balls from the bottom of PCBs. It was originally designed to work in Wave Solder applications, but solder balls on the bottom of the board from any process can be handled by this piece of equipment. If you would like more information on this machine, please e-mail me at psmith@dynapace.com. My recomendation, however, is first try to fix the problem, then, only if necessary, look at a machine that can take care of the issue. Paul R. Smith Dynapace Are there anyone who can give me the answer about solder ball problem? | | We have 12 layer PCB and double sided PCB. After one side reflow soldering We found lots of solder ball under the PCB. The solder ball was coming out from via hole. | | | So when we print the other side , there are lots of bridge | | | because of solder ball. | | | PCB MAKER said we can not get rid of melted solder in the via hole during HAL process. | | | Is it true or not. | | | Do I have to make things to remove solderball under PCB automatically after one side soldering. | | | I NEED YOUR EXPERIENCE. | | Kyung Sam, | It is the fault of your PCB manufacturer or your designer. they are getting solder in the vias in their process. When you send the substrate through reflow, the solder falls out. Tenting the vias is an option on the next spin. | | Justin | |

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Mike Cox

#14007

Re: SOLDER BALL UNDER THE PCB AFTER REFLOW SOLDERING | 2 October, 1998

Kyung Sam, |

| Justin is correct, there is definately either a board design problem or the PCB maker issue. Obviously there are many mixed technology boards built in the world so I would lean towards a design issue as the root cause. Should you or your PCB house not be able to come up with a solution, there is a machine designed to remove solder balls from the bottom of PCBs. It was originally designed to work in Wave Solder applications, but solder balls on the bottom of the board from any process can be handled by this piece of equipment.

|

| If you would like more information on this machine, please e-mail me at psmith@dynapace.com.

|

| My recomendation, however, is first try to fix the problem, then, only if necessary, look at a machine that can take care of the issue.

|

| Paul R. Smith

| Dynapace

| Paul These kids of solder balls are usually attached. Sometimes they will detach themselves but not very often. I don't think any conveyor in the world will detach a solder ball that is still soldered to the board. These balls usually result (as Justin stated) from solder in the via. Usually though only having solder in the via will not cause the ball to blow out, but rather an outgasing of either trapped air or moisture. We had a similar problem whereas the vias were tinted and plugged after the HASL process, then the solder would reflow expand and pooof solder ball.

Mike C |

| Are there anyone who can give me the answer about solder ball problem?

| | | We have 12 layer PCB and double sided PCB. After one side reflow soldering We found lots of solder ball under the PCB. The solder ball was coming out from via hole.

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| | | So when we print the other side , there are lots of bridge

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| | | because of solder ball.

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| | | PCB MAKER said we can not get rid of melted solder in the via hole during HAL process.

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| | | Is it true or not.

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| | | Do I have to make things to remove solderball under PCB automatically after one side soldering.

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| | | I NEED YOUR EXPERIENCE.

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| | Kyung Sam,

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| | It is the fault of your PCB manufacturer or your designer. they are getting solder in the vias in their process. When you send the substrate through reflow, the solder falls out. Tenting the vias is an option on the next spin.

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| | Justin

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Vincenzo Longobardo

#14008

Re: SOLDER BALL UNDER THE PCB AFTER REFLOW SOLDERING | 11 October, 1998

Dear Park Kyung Sam, your problem can be solved asking to your PCB supplier to cover all the via holes with solder mask before the HAL. Usually this is possible and doesn't produce extra cost.

Vincenzo Longobardo vinlong@tin.it

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