From wafer production and IC protection to chassis and DC cord, GE Advanced Materials can provide "wing-to-wing" electrical/electronics application coverage

Photo by Teresa McPherson/ASI

The electrical and electronics (E/E) industry turns out next-generation products perhaps faster than any other segment in the world. This rapid proliferation is due to intense, ever-increasing consumer demand and to the successful penetration of electronics technologies into virtually every other major sector, including automotive, healthcare, converged devices, telecommunications and computers. As such, constant change is the byword. Thus, suppliers of materials, equipment and other products to this industry must innovate faster than the manufacturing curve in an effort to bring their customers leading-edge technologies that can add value and provide differentiation in a crowded field. One such company is GE Advanced Materials, which has introduced several new product families for the growing E/E industry.

GE Advanced Materials is a newly organized GE business, officially formed on Jan. 1, 2004, and consisting of GE's three former materials businesses: GE Plastics, GE Silicones and GE Quartz. GE Advanced Materials, headed by President and CEO John Krenicki, and headquartered in Pittsfield, MA, is now in a position to bring together an array of proven E/E technologies and help customers develop meaningful, cost-effective product solutions. All three former GE businesses had a proven industry track record, and the combined product portfolio now offered under the GE Advanced Materials umbrella is extensive. Offerings include: quartz crucibles used to grow silicone ingots; heat-dissipating, interface-management materials to protect delicate integrated circuits (ICs); connector materials that can survive high-temperature infrared (IR) reflow soldering; silicone-based gels, coatings and encapsulants; high-performance polycarbonate and polyetherimide films; and wire coatings for plugs and direct current (DC) power cords.

Greg Adams, general manager, Global Marketing, GE Advanced Materials - Plastics, says, "Over the past two-plus years, while the materials industry was in a downturn, we didn't sleep. We repositioned, focusing on global E/E as one of our priorities. Now we're able to serve this sector better than in the past. GE Advanced Materials can touch almost every major segment of the industry, which is why we view ourselves as not just any materials supplier, but as a strategic, wing-to-wing, fully integrated supplier that can offer broad coverage virtually anywhere our customers need it."

GE Advanced Materials, Quartz - a leading producer of high-purity quartz and boron nitride for the semiconductor, electronics, fiber optic, lighting and cosmetic sectors - is a major supplier of quartz and pyrolytic boron nitride (PBN) growth vessels. The quartz crucibles, which can be as large as 32 inches in diameter, are used to grow silicon ingots from polysilicon chunks, which are subsequently sliced into the wafers on which circuitry is formed. These vessels are also used to grow silicon wafers for photovoltaic cells used in producing solar-power. Normally, the crucibles are single-use consumables because the surface of the crucible deteriorates under the heat stresses. However, in a joint development program with a leading wafer manufacturer, GE has developed a protective coating for the surface of the crucible, extending the life of crucibles and allowing for "re-charge" with polysilicon, thus significantly increasing output and single-crystal yield. PBN crucibles are used to grow gallium arsenide (GaAs) and other compound semiconductor ingots for the higher frequency chip applications used in the telecommunications and optoelectronics segments.

According to Jeff Davis, vice president of Marketing & Sales, GE Advanced Materials - Quartz, "GE Advanced Materials' technology starts at the beginning. If we look at semiconductor production, the wafer is born in quartz crucibles, chips are processed in quartz chambers, and our technology helps the chips reach their full potential through thermal-management materials that pull the heat out so integrated circuits can operate properly. We can leverage years of quartz and ceramic material experience to support this segment in a number of critical ways."

These can include electrically fused quartz tubing (up to 650 mm) and rods (up to 55 mm), also produced by the Quartz business group, that can be used to form the semiconductor equipment chambers, in which a wafer is subsequently treated to form IC chips. Additionally, GE can supply the industry's largest solid quartz ingots - now weighing up to four tons - which are machined down to form windows, boats, wafer carriers, plates, disks, flanges and other components for supporting wafers or containing advanced processes.

Other ceramic-based products include heaters and electrostatic chucks for semiconductor wafer processing. They are available as fully dense ceramic "sandwiches" of both PBN and pyrolytic graphite (PG), which are uniform, offer fast response and excellent thermal shock resistance, and typically have very low outgassing thanks to production by way of chemical-vapor deposition (CVD). Many alternatively available materials produced via sintering are often not as dense, potentially generating particles and outgassing impurities during IC manufacturing. Additionally, GE Advanced Materials produces PolarTherm® thermally conductive boron nitride fillers for adhesives, coatings, resins, and the epoxy laminates for the printed wiring board (PWB). These thermal-management additives can help pull heat away from the chip. For applications requiring the highest performance, GE's encapsulated TPG® thermal pyrolytic graphite can be used to solve hot-spot problems in heat spreaders, thermal cores (in PWBs), and laser-diode mounts.

"The high-tech processes we use to produce our quartz and boron nitride materials not only make the materials work harder for customers," Davis says, "but can also provide superior results. That means more reliable electronics for the ultimate customer: the consumer."

At this stage in the process, products from GE Advanced Materials - Plastics are often employed. Here, the company's special grades of low-ionic, high-purity LEXAN® resins, which also offer excellent impact strength and dimensional stability, are used to mold front-opening shipping boxes (FOSBs) that transport bare wafers from the ingot grower to the wafer fabs. The valuable wafers are then transported from one production step to another at the fab in front-opening unified pods (FOUPs) as they are systematically processed and loaded with intricate circuitry. FOUP shells molded from ULTEM® or LEXAN resins, and frames molded from ULTEM resin or carbon-fiber-filled polyetheretherketone compounds from LNP Engineering Plastics, help protect up to 25 wafers from bumps, contaminants, static discharge, outgassing, and other hazards as they move robotically through the semiconductor processing room.

Once dies or chips have been produced and cut from the wafer, GE Advanced Materials' silicone products are used to attach and protect the integrated circuitry and surrounding components on the board.

"We look at our role as one of safeguarding both the chip and board-level components; we make them more rugged and resistant to their environment," says Wayne Hewett, vice-president, general manager, GE Advanced Materials - Silicones. "This is the domain of silicones. Here we provide thermal-interface products that pull heat from the chip; gels and elastomers for encapsulating and potting semiconductors; adhesives and sealants that attach components and seal out contaminants; and conformal coatings that protect the printed-circuit board itself. Almost everywhere in electronics, GE's silicone products add performance and value.

"One of our specialties is tailoring products to meet the needs of our customers," Hewett adds. "With the fast growth of personal devices such as digital cameras, personal digital assistants (PDAs), and cell phones, as well as the rapid miniaturization of medical diagnostics and other devices, we're seeing more of a demand for high-performance silicones than ever. The portable device segment is exactly the type of application area where, for example, our conformal coatings and vibration damping gels can really shine. They help to protect high-value electronics from contamination, electrical shock, and mechanical shock from rough handling."

One powerful trend affecting virtually any material used at the board level or below is the rapid and steady increase in thermal management. In fact, thermal-interface management is an estimated $3.7 billion segment, experiencing an average 6% annual growth rate, which makes it one of the fastest-growing segments of the semiconductor industry. Therese Jordan, Marketing manager, defines thermal management as managing thermal dissipation or the dissipation of heat across any heat generating object, or specifically the chip or dye. As the generations increase, there becomes a great need to pull heat from the semiconductor chip or dye.

The rapid increase in electrical density on circuit boards directly translates into higher heat loads. "Everybody's bumping up against the thermal barrier," Hewett says. "You could say the electronics industry is waging a war with heat these days as devices get smaller and circuits run faster and with more functionality. The trick is to figure out how to get the heat out quickly and efficiently. While effective design will help, the thermal budget is in the interface. The key has to be to move those BTUs somewhere else; that means developing better thermal-interface management products that form a bridge between the heat source and the heat extraction materials."

GE's silicones business is responding to this challenge through its family of low thermal resistance (LTR) die-attach adhesives and greases. The company has unveiled a new line of LTR materials called SilcoolTM LTR®. Compared to currently available products, these products will enable use of a thinner bond line between the semiconductor and heat spreader, thereby improving the thermal pathway. In addition, GE will be introducing in the second half of this year a thermal grease for people looking for a reworkable thermal grease.

Another GE family of high-performance silicone products is currently being used to meet increasing thermal demand in applications where the trend is moving toward the use of longer-lasting gallium-nitride LEDs with higher brightness and greater resolution for displays and various types of lighting. These new-generation LEDs run at higher power and temperatures, and require a brighter, more reliable white light source than in the past. This, in turn, requires the materials that protect them to shift to higher performance silicone polymers as well. The epoxy encapsulants that were used for older LEDs often yellowed and lacked the optical efficiency and lifespan for use on the newer style gallium-nitride lights. High-clarity, non-yellowing silicone gel encapsulants in the InvisisilTM line from GE Advanced Materials can provide a more robust solution for the new LED emitters, helping protect components from moisture, shock, and temperature extremes. Benefits of this line include silicone's tendency to non-yellow when used as an encapsulant, Jordan says; in addition, it has a high refractive index and ultra-clarity - it doesn't reflect, refract, or scatter - and it lasts a long time.

Hewett says the success of GE Advanced Materials' silicones business is the result of being in touch with customer needs. "This industry moves very fast and requires suppliers to be close to their customers - it's necessary if you want to stay in the game. We always push ourselves to be where our customers need us," he says.

Underscoring this commitment is GE Advanced Materials' Electronic Materials Technical Center in Gotemba, Japan, scheduled to open in the first week of June. At this center, staffed by 20 scientists, the company plans to offer customers full-scale characterizations of a range of electronic materials, employing state-of-the-art equipment, product and processing guidance, and testing expertise. The center will house a full flip-chip assembly line, as well as failure- and reliability-analysis equipment. "We're making a significant investment in this facility to drive our electronic materials business forward everywhere we can," Hewett says.

Thermal challenges are also pushing performance requirements for insulation films used in capacitors, bobbins, conductive-ink substrates, shielding films, tapes, flexible heaters, bar-code labels, wire and cable jacketing, and flexible circuits. In many applications, such films are now being pushed into performance ranges that exceed the thermal performance of traditional polyester and polycarbonate resins. In this demanding category, GE's ULTEMTM polyetherimide (PEI) films are being viewed as cost-performance alternatives, offering a number of potential benefits over more costly polyimide- (PI) based film products. For instance, PEI is self-sealing and also seals to other materials. It can also be metalized and offers good, broad chemical resistance; high thermal and low dielectric performance; and good dimensional stability.

New ULTEM 1000B film, for example, offers VTM-0 flame retardancy across a range of gauges. ULTEM 5000B film, also just recently introduced, offers excellent thermal performance, a glass-transition temperature (Tg) of 225

About GE Advanced Materials

GE Advanced Materials is a world leader in providing materials solutions through engineering thermoplastics, silicon-based products and technology platforms, and fused quartz and ceramics. Headquartered in Pittsfield, MA, GE Advanced Materials is the combined entity of GE's former Plastics, Silicones and Quartz businesses. Its offerings include the following.
  • Silanes, specialty silicones, urethane additives, adhesives, sealants, caulks, resins, and elastomers for a variety of industries such as personal care, automotive, tire and rubber, construction, healthcare, electronics, household and institutional, agriculture, textiles, appliances, bedding and furnishings, and foam control, as well as the consumer "do-it-yourself" industry. For more information, visit .
  • Engineering thermoplastics resins serving customers in a variety of industries, including aerospace, appliances, automotive, building and construction, data storage and optical media, medical, electrical and electronics devices, telecommunications, computers and peripheral devices, outdoor vehicles and devices, and packaging. For more information, visit .
  • High-purity quartz and advanced ceramic materials for the semiconductor, telecommunications, lighting, electronics, personal care, and water purification industries. For more information, visit .

PolarTherm, TPG, LEXAN, ULTEM, THERMOCOMP, and NORYL are registered trademarks of General Electric Co.

ILLUMINEX, Silcool and InvisiSil are trademarks of General Electric Co.