How is component tombstoning prevented during Microvia pcb?

component tombstoning prevented during Microvia pcb

Tombstoning, so called because it resembles the slanted slabs of granite commonly found at cemeteries, refers to a condition where two adjacent pins of a surface mount component rise up from their pads. This can result in an open circuit, thereby destroying the functionality of a pcb assembly. The cause of this phenomenon is a difference in the wetting speed of the solder that anchors the component to its pad. The difference in wetting speed is the result of a variety of factors, including differences in solder paste chemistry and temperature fluctuations during reflow.

As a result of the miniaturization trend in electronics, more and more components are being packed into smaller spaces on microvia pcb. This has increased the likelihood of tombstoning, as the small component sizes have a higher tendency toward this problem. Another contributing factor is the use of traditional HASL (hot air surface leveling) finishes on a board, which can make the surfaces uneven and impact how solder adheres to them.

When the pcb manufacturer uses high-precision stencil printing equipment to deposit solder paste, the paste is more evenly spread, and this can prevent tombstoning. This also helps to ensure that the paste is applied at the correct thickness. In addition, the manufacturer should also use the right reflow oven settings to control the temperature and conveyor speed.

How is component tombstoning prevented during Microvia pcb?

A common solution to tombstoning is the use of a via or PTH filling technique, which involves inserting a solid epoxy into a hole that will not be used. This can help prevent the wicking of solder from one pad to the other, and it will make it more likely that wetting takes place simultaneously on both pads. Alternatively, it is possible to create a solder mask dam between the pad and the via or PTH to accomplish the same goal.

Another way to prevent tombstoning is to use a copper plating process on the board, which can be done in multiple layers. The holes that will be used are plated with copper, while the holes that are not to be used are non-conductively filled or plated shut with epoxy. The plating process can also be done with a specialized bath and chemistry to reduce the possibility of tombstoning by slowing down the wetting speed of the solder.

In addition to the above best practices, it is important to work with a contract manufacturer that is equipped with industry-leading expertise in the design and fabrication of electronic circuit boards. This includes the ability to create accurate CAD footprint models and routing recommendations for tiny components. In addition, they will ensure that the pcb board has the right thermal profile to mitigate tombstoning. A reputable manufacturer will be able to produce high-quality PCBs that are free of defects like tombstoning. To learn more, contact a company like Rush PCB Inc.

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