Testpoints in production using finepitch/BGA packages (mobile phones etc)

[Klaus Kragelund]

Hi

I am going to investigate if we can get some of the active components
cheaper by going from standard packages (SOT-23 etc) to finepitch
(SC70, BGA etc) and perhaps also save some space.

I see one problem though. Our production test people like to have a lot
of testpoints to do either functional tests (flying probe) or ICT (In
Circuit Test - impedance).

But, going to finepitch means we no longer have space for the
testpoints - and the production cant measure on the SMD leads/pads.

Today I took two old standard mobile phones and did some reverse
engineering. They seem to have very few testpoints. So I wonder - can
anyone with experience in high integration devices tell me how they do
ICT? Boundary scan or another fancy way?

Thanks

Klaus

PS See picture of the mobile phones here (Nokia 3210 and Siemens
6100):

www.microdesign.dk/tmp/mobile_cropped_small.jpg

 

[martin.shoebridge]

).

But, going to finepitch means we no longer have space for the
testpoints - and the production cant measure on the SMD leads/pads.

Today I took two old standard mobile phones and did some reverse
engineering. They seem to have very few testpoints. So I wonder - can
anyone with experience in high integration devices tell me how they do
ICT? Boundary scan or another fancy way?

Thanks

Klaus

PS See picture of the mobile phones here (Nokia 3210 and Siemens
6100):

www.microdesign.dk/tmp/mobile_cropped_small.jpg

Almost certainly JTAG

 

[PeteS]

Hi

I am going to investigate if we can get some of the active components
cheaper by going from standard packages (SOT-23 etc) to finepitch
(SC70, BGA etc) and perhaps also save some space.

I see one problem though. Our production test people like to have a lot
of testpoints to do either functional tests (flying probe) or ICT (In
Circuit Test - impedance).

But, going to finepitch means we no longer have space for the
testpoints - and the production cant measure on the SMD leads/pads.

Today I took two old standard mobile phones and did some reverse
engineering. They seem to have very few testpoints. So I wonder - can
anyone with experience in high integration devices tell me how they do
ICT? Boundary scan or another fancy way?

Thanks

Klaus

PS See picture of the mobile phones here (Nokia 3210 and Siemens
6100):

www.microdesign.dk/tmp/mobile_cropped_small.jpg

Probably boundary scan, although some devices have a NAND chain
internally for testing too.

Cheers

PeteS

 

[Klaus Kragelund]

PeteS skrev:

Probably boundary scan, although some devices have a NAND chain
internally for testing too.

Ok - so the next question:

For analog stuff with high integration, do you place testpoints to be
able to find any failed part in the ICT test (almost all nodes needs to
be testpoints) - or do you rely on vision systems, functional tests or
another method?

Regards

Klaus