Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


CCGA

Dhanish

#33508

CCGA | 3 April, 2005

What is the recommended stencil aperture opening ,stencil thickness and aperture shape for CCGA?We are seeing high reject for Open solder joint.

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#33510

CCGA | 3 April, 2005

In 2001, IVF evaluated the reliability of IBM CBGA and CCGA, i.e. packages with "hard" balls and columns, in space applications for the European Space Agency. One clear result was that amount of solder paste printed on the solder lands is very critical for the fatigue life of solder joints to CBGA. If too little solder paste is printed, it will result in a meager solder fillet between the ball and the solder land on the PCB, since the ball does not melt. If the diameter of the solder fillet becomes less than the diameter of the ball [column] it decreases the fatigue life dramatically. Meager solder joints may also be caused by warpage of the PCB and some ceramic packages, depending on their construction and thickness. So if you go for packages with hard balls [columns], we recommend that you look over how you control that the right paste volume is printed on the solder lands prior to mounting the components.

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GS

#33538

CCGA | 4 April, 2005

Solder volumes is very important parameter to keep under control in order to get a good and reliable CCGA solder joint, and an automatic 3D paste volume inspection is strongly recommended practice to use. Questions: - what Column pitch do your CCGA have ? a) 1,27 mm? b) 1.00 mm? - how are the PCB pad finisched ? OSP Enig? HAL? - Are you using Clean or NC solder paste?

rgds GS

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Dhanish

#33539

CCGA | 4 April, 2005

Questions and answers - what Column pitch do your CCGA have ? a) 1,27 mm?b) 1.00 mm? 1.27mm - how are the PCB pad finisched ? OSP Enig? HAL? OSP - Are you using Clean or NC solder paste? Clean

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RDR

#33552

CCGA | 5 April, 2005

We use 1:1 with an 8 mil stencil for these parts.

Russ

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GS

#33645

CCGA | 11 April, 2005

For 1,27 mm Column Pitch, we set our process like this:

- Stencil 0,20 mm If allowed also for other SMDs otherways some time 0,150 with step up stencil used only for CCGA area. - paste height min 0,175 mm - aperture 0,75 to 0,8 mm - paste volumes from 3000 to 7600 cubic mils (By Cyber or SVS 3D API) when column lenght are around 2,2 mm best volume range is from 4500 to 5500 cubic mils.

Other details : Paste Type-3, on OSP, Clean Process.

Quality yield very high.

Regards

GS

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