DfR Solutions | Insights | Electronics Reliability

Underfill Applications, Materials & Methods

WHAT is UNDERFILL AND WHY is it USEFUL?

Underfill is thermoset epoxies traditionally used in flip chip applications to reduce thermal stresses solder bumps experience due to coefficient of thermal expansion mismatch between a die and the organic substrate. Today, underfills are available in a variety of formulations and are widely used for board level reliability of ball grid array components by reducing thermal and mechanical loads under harsh use environments. Careful consideration to the underfill material properties and intended use environments must be made to assess the relative reliability improvements underfills offer.

Topic: Electronics Reliability, Solder Joint Fatigue, solder joint, Mechanical Design, integrated circuits, Reliability Physics

Here at DfR Solutions, we perform hundreds of design review projects a year. Sometimes companies come to us when they are considering a new electronic product and have only the initial designs. In other instances, companies approach us only after their product has already been configured, requesting a review of the final design before moving forward to the manufacturing stage. Ideally for the client, they are in the former group, partnering with us as early in design process as possible. It’s much more efficient (time- and cost-sensitive) to gather all available information and thoroughly check for potential failures of a design before nailing parts down, rather than to complete an assembly only to discover it doesn’t function properly in its use case scenarios.

Topic: Electronics Reliability, electronics test design, Mechanical Design, Reliability Physics, Standards Based Testing

In a previous DfR Solutions insight titled Best Practices in Test Plan Preparation, we discussed some of the most important techniques and philosophies when preparing to develop a testing plan for electronic products. What makes those techniques so powerful is that they are ubiquitous: with any design, reviewing the bill of materials, identifying use environments and assessing failure history are both applicable and crucial.

However, what that article did not discuss is that there are considerations that need to be applied in very specific ways. The following are strategies for test plan development that are dependent on specific use cases, parameters, goals, configurations and limitations. While they are just as powerful as our Best Practices, they require a thorough understanding of your product and a clear and agreed-upon set of goals throughout the supply chain.

Topic: Electronics Reliability, electronics test design, Mechanical Design, Reliability Physics, Standards Based Testing

Best Practices in Test Plan Preparation

Product test plans are critical to the success of a new product or technology. Preparing a viable test plan involves several steps to properly identify the requirements for the tests. While many test parameters will vary from product to product, there are elements of the methodology for a test plan approach that remain consistent. These include the necessity for a BOM review to determine part limitations, assessing the field environmental conditions so they can be properly mapped to the tests implemented, and the impact of failure history, should it exist. The objective is to develop a test plan that does not stress the assembly to a level where a failure might not be experienced in the field.

Topic: Electronics Reliability, electronics test design, Mechanical Design, Reliability Physics, Standards Based Testing

Recently I, Greg Caswell, had full knee replacement surgery on my left knee to fix a problem with osteoarthritis. I found the overall experience interesting in that the approach the doctor’s used to assess the issue, develop a plan for improving the joints capabilities and finally performing surgery as the last possibility, was similar to the Physics of Failure approach DfR Solutions uses.

Topic: Electronics Reliability, electronics failure, reliability testing

Performing a “before a failure” investigation on electronics is typically done for various reasons. One reason is to identify weak components or sub-systems before committing to a full-blown production run and its associated expenses. Comparison testing of similar component parts to reduce costs and increase reliability of existing designs, or against a competitor’s offerings is another reason. A “before a failure” investigation can validate a design to satisfy customer or market specifications, or regulatory obligations, which is common among the aerospace and medical devices fields.

Topic: Electronics Reliability, electronics failure, reliability testing