Nexlogic

A PCB trace could get damaged due to multiple reasons, for instance, physical damage done to the trace while handling the board. Also, a trace can be damaged due to contamination in tank chemistry. This might change chemicals strength inside that tank, thereby causing weak traces that can easily be damaged or flake off.

Mis-alignment of the component leads going to a PCB’s SMT pads could be caused by the wrong amount of paste deposition or thermal profile.

An ATE PCB pick and place system is unlike those used for conventional PCBs. This one has the capabilities for handling larger footprint boards, 20 x 24-inch, up to a maximum size of 26 x 30-inch.

Loop back traces used in an ATE PCB design go from and to the pin of the DUT (device under test), typically a BGA package.

When SMT printing is misaligned, the assembly will not be optimal since the paste is not covering 100% of pad on the surface of the board. Consequently, the result is an inadequate solder joint.

When the thermal profile in the reflow oven isn’t correctly created, expect a bunch of shorts/bridges under BGA devices and connectors.

When the speed of the pick and place machine is set too high, components may not be properly placed and might jump, resulting in placement at a wrong location.

Here is a solder bridge between pins caused by improper printing or poor stencil design.

Offset printing of paste means solder joints on SMT pads would be un-reliable. Either a mismatch in the paste layer file versus actual component layer file causes it. Or designing the wrong paste layer file may create it.

Dog-bone fan-out is used for BGAs with 0.5 millimeter (mm) and above ball pitch. Pitch is defined as the spacing between the center of one BGA ball to the center of the next one.

This is an example of a BGA with voids. These voids are due to poor reflow soldering either from insufficient solder paste dispensed on the BGA’s balls. Or reflow oven temperatures were not correctly calibrated.

Mis-aligned component placement occurs when an improper thermal profile is used. Components that were supposed to be soldered on the boards come off with slightest movement on the board.

ATE PCBs must be comprehensively cleaned due to the design-under-test or DUT area. Eliminate any type of foreign bodies on the board like fingerprints, hand lotions, and body perspiration. A permanent fingerprint, for example, may jeopardize the high-speed integrity of an ATE PCB.