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LGA Placement
Several clients recently have come to BESTProto where the build has included Land Grid Array (LGA) package types. Land Array packages are part of the Bottom Terminated Component (BTC) family whereby lands are on the bottom of the device and no solder interconnect means are attached (such as columns, balls, pins, etc..).
Some of the benefits of the LGA package over its "cousin" the BGA package include:
· LGA devices can be used for either lead containing or lead-free assemblies depending on the
surface mount technology (SMT) assembly solder paste used.
· LGAs eliminate the risk that customers receive components with missing or damaged spheres due to
shipping or handling.
· LGA devices have a lower mounted height than BGA. This can allow for more space above the
device for a heat sink solution or for small form-factor applications.
· The durability of the LGA in mechanical drop is typically greater than the BGA that is not underfilled.
· LGA packages can use the same recommended board assembly process as CBGA.
BESTProto has a wealth of experience in dealing with such advanced package types in order to make your build go well.
The key to the correct placement for these device types can be found in:
- Proper thermal profiling
- Proper stencil design to accommodate the variations in solder volume required for the lands versus the large center ground
- Dealing with embedded devices which can shift during reflow
While the placement and assembly of these devices is important to the success of the prototype build their inspection post reflow is also important. This requires that inspection tools and experienced operators be used to perform the inspection. It is critical that the proper XRAY images are captured in order to verify that no solder shorts are present, no parts have have been distrubed during assembly and that voiding is kept to a minimum. In addition, endoscopic inspection will help determine the proper collapse at the corners of the device. Finally, visual inspection will insure that parts in the vicinity are aligned and placed well for the prototype runs.
Call BESTProto today to see how we can be of assistance in making your proto build with LGAs a success! |
