Steve DeCollibus, Managing Editor, Semiconductor Packaging News

If like me, you have been concerned or have wondered why large EMS and OEM manufacturing companies have had recalls due to thermal failures that have created millions of dollars in loss and upset consumers.

If you have seen the recent U Tube controversial cell phone popcorn demo, where four students place their phones in a plus sign configuration that leaves an open square in the middle where popcorn kernels are placed and popped as a result of the four phones being called simultaneously.

Or if you have been reading some of the medical reports coming out of Europe that are tying cell phone use to possible brain cancer developing in the kids who are using them, you might wonder why this is happening and what can be done to mitigate the problem.

To get a better idea of why these conditions can come about and to learn a little more about shielding and thermal management, I visited the Chomerics Division of Parker Hannifin Corporation in Woburn Massachusetts. They have been involved in developing solutions for EMI shielding and thermal management since 1961.

While there I was amazed to see the depth and scope of solutions that are available to solve these problems as well as the amount of R&D and specific investigations into customer solutions that were underway at the company. Their spokesperson, Dr. Percy Chinoy agreed to answer a few questions regarding my concerns.

Steve DeCollibus: Dr. Chinoy, why do you think we are seeing more than a few of these kinds of failures happening? Is it lack of proper testing, poor product selection, cost restrictions?

Chomerics' spokesperson Percy Chinoy PhD

Dr. Chinoy: The intersection of communication, computer and consumer markets has generated a growing demand for ubiquitous wireless connectivity, higher bandwidth and advanced computing features all in a shrinking footprint. As a result, heat dissipation, power consumption and electromagnetic interference (EMI) have become significant challenges in portable electronics.

For example, power densities (Watts/mm2) in advanced chips such as multi-core microprocessors and light emitting diodes (LEDs) have been rising rapidly. Rigorous design and testing of thermal management and EMI shielding can run into trade-offs with shorter design cycles and severe price pressures thus increasing the probability of failures in the field.

SD: Are there steps that a manufacturer can take to avoid these problems?

Dr. C: Thermal management and EMI shielding have to be designed-in at the chip level, board level and system level earlier in the design cycle and validated with reliability testing. For thermal management, particular attention needs to be paid at the interfaces, e.g. chip-to-heat spreader, heat spreader-to-heat sink/housing, which can be a substantial part of the total thermal budget.

At Chomerics ourthermal interface materials (TIMs) such as gap filler pads, gels, adhesive tapes, electrically insulating but thermally conducting pads, greases, phase change materials and flexible heat spreaders provide the designer with a variety of solutions to minimize interfacial thermal impedance at different price-performance points and ease-of-use form factors.

SD: How does Chomerics help customers solve these problems before they occur?

Dr. C: Chomerics' network of applications engineering, product management and sales works closely with the customer to assure proper material selection and design to meet customer specifications. Wherever necessary, the Chomerics R&D team will develop a custom material formulation or a combination of thermal and EMI materials.

Chomerics has a history of collaboration with OEMs to develop and qualify TIMs for specific applications, e.g. dual and quad core microprocessors for laptops, desktops and servers, graphics processors for gaming, ASICs and chipsets for communications equipment.

Chomerics has collaboratively conducted extensive accelerated aging tests to ensure integrity of thermal properties over the lifetime of the product.

Bottom line, there are solutions to these problems, but without rigorous testing thermal management and EMI shielding become another discard in the cost reduction deck. And OEM's and EMS companies lose when they do not follow through on these issues.