Northwest Passage
Near Nature; Near Perfect
By Gail Flower, editor-in-chief

In one of the most beautiful areas imaginable in the Pacific Northwest amidst flowers and greenery, Honeywell Electronic Materials employees accomplish leading-edge research and development to create thermal interface materials, heat spreaders, and solders. As packages grow in functionality and performance densities increase, and as a result of shorter pathways for current to flow, the temperature correspondingly goes up. To understand how each package design works and what is needed to control the resulting heat flow, Honeywell engineers conduct basic thermal analysis from a chemical, materials science, and metallurgical point of view as an initial step in analyzing how to dissipate heat. Honeywell Electronic Materials specializes in thermal interface materials of many types including those that go between the die and heat sink as a TIM 1, low alpha and lead-free under-bump metals and metallurgy, die attach, performs, and heat spreaders.

We visited Honeywell in Spokane, WA, on a sunny day this spring. Scott Miller, product line manager for interconnect packaging solutions welcomed the Roadshow staff at the door with lots of information about the area as he began the tour. "Spokane is known for lots of things: mining lead and cadmium early on, farming, manufacturing of shoes, the longest gondola ride in the world, snow, and potholes, of course." But not everything is invented in Spokane, he assured us. The Spokane operations were under ownership of Johnson Matthey, part of the overall Johnson Matthey Electronics (JME) business. In 1999, AlliedSignal acquired JME and it became part of the AlliedSignal Electronic Materials business. Later that same year, AlliedSignal and Honeywell merged, keeping the Honeywell name. Known as Honeywell Electronic Materials (HEM) ever since, they have become one of the leading materials suppliers to the semiconductor industry. While HEM currently serves the core semiconductor market, it is now branching out into adjacencies such as displays, and photovolatics.

"Our Spokane and Bay Area operations (Santa Clara and Sunnyvale, CA) are a cornerstone of US based research and development as well as manufacturing for HEM," says Devesh Mathur, Ph.D., director of R&D in metals. At the same time, HEM is a global business with sites in the U.S>, Europe and Asia Pacific regions, including headquarters and a research and development center of excellence in Shanghai.

Strategy and strategy development are key elements of Honeywell's way of doing business. In that light, each year an updated 5-year plan is reviewed as a part of strategic planning for future growth. It seems to be working — Honeywell Corporation has grown to nearly $35B in revenue in 2007, which includes $12B in aerospace, $12.5B in controls, $5B in transportation systems and $5B in specialty metals (the division that HEM reports in through). It has 120,000 employees in more than 100 countries worldwide.

HEM's specific offerings include PVD metallization targets and coil sets, precious metals, low-alpha lead products, lead-free solder products, TIM1, TIM2, heat spreaders, and other materials that are designed to transfer heat out package layers. The company's PCM 45 continuous roll bulk and printable material is used to reduce heat in the TIM 1 and TIM 2 layers. Moreover, HEM provides advanced spin-on materials for applications such as insulation, planarization and lithography as well as electronic chemicals, etchants and cleans and precious metal thermocouples.

"In the past two years, we have expanded our work in packaging by adding wet labs for new chemistry, new test devices like the air flow test chamber, an explosion-proof mixing area for new materials, reliability chambers, thermal test vehicle testing and others," said Patrick Underwood, Ph.D., R&D manager, interconnect packaging solutions. They later reviewed how they do thermal impedance testing for ASTM D5470. One of the products supplied in a continuous roll, PCM 45, is a phase-change materialÑsoft at operating temperature but hard at room temperature. Other materials include aluminum bonding wire for die attach, solder performs, under-bump metallization, and nickel-plated copper heat spreaders.

As we toured the six buildings, we noticed the ESD flooring and hoods covering areas where fine aerosolized explosive materials would be handled. Other areas looked more like polymer chemistry labs where metal fillers are added to the mix to transfer heat out of packages. Some materials are screen printable, such as PCM45-SP TIM. Some are dispensed like their Advanced Polymer Solder (APS) TIM. Some roll out as needed. Each building had a function from basic R&D testing through production of materials in various formats and shipping. "We produce quite a substantial amount of phase change material (PCM) tape per month to supply chip sets and CPUs," says Mathur.

The test labs were packed with various pieces of equipment. "One of our newest tools is a flash diffusivity tester for evaluating the thermal diffusivity of materials" Andy Delano, Ph.D. said. Engineers can measure the thermal diffusivity of up to three layers simultaneously, allowing for accurate measurement of thermal interface material performance in-situ. Other capabilities include reliability testing through repeated temperature cycling, aging, temperature humidity, and HAST.

We didn't expect to see state-of-the-art tool-and-die operations, but before we entered Building 4, we donned steel toe shoes for standard safety protection and headed in. "We do EDM machining here for precision tool design for final customer parts," Scott said. In this part of the operation we viewed sinker and wire electro-discharge machining (EDM). The large CNC machines, mills and stamping machines with pull and form features surrounded us. We noticed the coil and stripping of copper. For mechanical finishing, a deburring machine used a vibratory system to round-out copper parts for customer specific finish.

Our next stop was the metrology lab where precision and measurement took over. Large contact measurement machines with touch probe measured dimensional features at less than 0.002 inch tolerances for final parts. Because their reputation is built on quality, engineers pay close attention to grain size control, purity and precision, from large forging, casting, and machining of metals to refining.

"We have great technical solutions for our customers, from heat spreader for heat dissipation and designs for environmental friendliness to a new dispensable thermal interface material, APS, for reliability and performance," commented Mathur. "You'll find our products in all types of electronic devices that need cooling." To test the end results, we viewed engineers using the latest equipment: scanning acoustic microscopes looking at voids in bonds, scanning electron microscopes for close up viewing, Instron strength testers, profilimeters and thermal resistance testers.

"When we design thermal interface materials (TIMs) and heat spreaders, our goal is to minimize thermal resistance of a device," explained Delano. "Managing heat up-front, closer to the die in is unique to Honeywell."

Another new application to manage heat is to use a phase-change material. PCM45-SP (referred to as screen printable, available in a can) is Honeywell's product in this area that allows customers to apply the material in a variety of shapes, depending on the design.

We left the Spokane, WA-based research and development center with a great deal of respect for the research and dedication the engineers at Honeywell conveyed. When it comes to developing critical advanced packaging materials for semiconductor manufacturers, including thermal management, electrical interconnect and burn-in materials, they know the subject well and have the skills to tackle the problem.

Honeywell Electronic Materials, Spokane, WA
Figure 1. We visited Honeywell Electronic Materials in their Spokane, WA location. We toured their R&D center and talked about their thermal management and electrical interconnect products. (L-R) Andy Delano, Ph.D., R&D manager, Advanced Thermal and Thermal Interface Materials, interconnect packaging solutions; Scott Miller, product line manager, interconnect packaging solutions; Patrick Underwood, R&D Manager; Heat Spreaders, interconnect packaging solutions; Devesh Mathur, Ph.D., R&D Director, interconnect packaging solutions, and Gail Flower, editor-in-chief, Advanced Packaging magazine.	Figure 2. Miller points out some of the many assembly materials that Honeywell contributes to the packaging area from thermal interface films, to die attach, performs to heat spreaders in diverse formats.	Figure 3. The air flow test chamber draws air across a package to see how the heat is dissipated, Delano explains.
Figure 4. Rick Townsend and Dave Steele do thermal impedance testing to see how materials work.	Figure 5: Organic polymers with metal fillers are produced in film form.	Figure 6. These singulated tapes with release tabs enhance a heat sink's cooling ability. They are shown in a release test.
Figure 7. The R&D lab at Honeywell tests material performance.	Figure 8. Many of the thermal interface materials for TIM 1 and 2, solders, performs, burn-in materials, are produced as polymers with metals and distributed through rolling mills.