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CCGA - Stencil design and Reflow Profiling

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#83060

CCGA - Stencil design and Reflow Profiling | 24 July, 2019

Hi Team,

Can anyone suggest me best stencil opening for CCGA.

Attached is the component details.

Solder paste : water solube - ORL0 - Jtsd 001 ( Sn63/Pb37)

Any one has qualified the same.

Regards, Ameen

Attachments:

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#83065

CCGA - Stencil design and Reflow Profiling | 24 July, 2019

Your solder stencil design should follow all basic rules for solder stencil design are followed in accordance with IPC-7525 including adherence to an area ratio of 2:3 or greater and an aspect ratio of 1.5 or greater.

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#83098

CCGA - Stencil design and Reflow Profiling | 30 July, 2019

thanks dave ..

I have one more query on the same CCGA.

What are the chances of the CCGA lead getting bent or tilt during reflow soldering process.

Concern :

to achieve the minimum peak temperature of 208 deg C at the connecting leads.

On body temperature for the component is around 235 deg C.

Maximum allowable temperature limit is 230 deg C.

Please help how to encounter this issue.

Regards, Ameen

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#83099

CCGA - Stencil design and Reflow Profiling | 30 July, 2019

Your inputs are always valuable and help a lot. Thanks for the inputs.

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#83101

CCGA - Stencil design and Reflow Profiling | 30 July, 2019

Attached is the image of lead lift in ccga

Attachments:

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#83103

CCGA - Stencil design and Reflow Profiling | 30 July, 2019

I'd be surprised if CCGA leads were getting bent or tilted during the reflow soldering process. If they were bent during handling, that would be less surprising.

235*C on the body for a minimum peak temperature of 208*C at the connecting leads doesn't surprise me. It sounds correct.

On to your picture: What kind of leads do you have? I think not 90Pb/10Sn or 80Pb/20Sn. Where did the lead material go?

Tells us more about your reflow recipe ... time above liquidous, soak time, and ramp rates.

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#83104

CCGA - Stencil design and Reflow Profiling | 30 July, 2019

Ameen: Send me your email address by selecting the link under my avatar to the left. Thanks.

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#83108

CCGA - Stencil design and Reflow Profiling | 31 July, 2019

Hi Dave,

lead is 80Pb/20Sn.

Top joint off CCGA lead is SN63/Pb37.

Thermocouple was placed at center lead of the CCGA and one at the corner lead of CCGA.

Ramp Rate Center 1.09 Corner 1.26 Soak ( 140 - 160 deg C ) Center 37sec Corner 38sec Reflow ( Above 183 Deg C) Center 82sec Corner 79sec Peak Center 208 Corner 219

Solder paste : Water soluble paste ( ORL0 - Flux chemistry ) Alloy : Sn63/Pb37

Stencil Thickness : 7 mil

Solder paste height : 5.6 to 7.5 mil

Regards, Ameen

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#83144

CCGA - Stencil design and Reflow Profiling | 2 August, 2019

I don't get it. The liquidus of 80Pb/20Sn is like 280*C. Your reflow temperature got nowhere near that value.

Where did that material go? Is it folded back under the component? Disappeared? Was it ever there?

Ask someone while analysis tools to help explain things. Go to an analytical lab or materials department at your local university for help.

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#83191

CCGA - Stencil design and Reflow Profiling | 7 August, 2019

Hi Dave,

Yes the lead was there before reflow.

After reflow it has bent inside. The component was inspected before placement.

We are unable to analyze, what might have went wrong.

Regards, Ameen

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#83234

CCGA - Stencil design and Reflow Profiling | 9 August, 2019

Did you check the pin location accuracy before placement? I mean if possible pin was hit or misaligned a little before placement, so the pin cannot inserted in hole then bent.

And maybe you need contact your component supplier to study together.

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#83247

CCGA - Stencil design and Reflow Profiling | 13 August, 2019

Hi ,

Thanks for the reply.

Yes CCGA was checked before placement and sending to reflow oven.

The latest suspect form few cross functional team member is like.

It is due to improper reflow profile " Column kick out " has happen.

I am attaching the profile. Where thermocouple as attached at different position.

Please have look and provide feed back please.

Regards, Ameen

Attachments:

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#83328

CCGA - Stencil design and Reflow Profiling | 21 August, 2019

And what is the solder paste selection recommendation for the same.

1. Water soluble ( organic based flux solder based ) 2. No clean ( rosin or resin based solder paste )

customer is suggesting water soluble chemistry , which is having lot hot and cold slump issues.

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#83337

CCGA - Stencil design and Reflow Profiling | 22 August, 2019

From the picture you present, it is a pin in paste part with pin length 2.2mm (a good length for 1.6mm PCB thickness), and seems the pin tilted and touch on PCB surface, thus causes up-part. Sorry I cannot image pin tilted not before placement but is caused by re-flow profile because the pins shall be all inside holes and CCGA fully seated on PCB surface after placement, that's placement purpose, right? Only in the condition that this pin back out of hole and touch PCB during re-flow because material heating issue, but this is really surprising.

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#83346

CCGA - Stencil design and Reflow Profiling | 23 August, 2019

Hi ,

Its CCGA part . with normal PCB pad opening similar to other BGA pad .

Yes its very surprising and we are not able to analyze. What exactly went wrong.

We have new stencil design for this now. Will run it tomorrow. Will update the results.

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