Category Archives: Materials and Equipment

Apr. 9, 2008 – Sunovia Energy Technologies and EPIR Technologies say their R&D efforts have achieved “breakthroughs” in infrared sensors that will enable multijunction solar cells with high efficiencies and lower costs, through using less expensive IR system materials and manufacturing processes.

Specifically, the achievement is a MCT IR focal plane array grown directly on a thin cadmium telluride (CdTe) epilayer, which in turn was grown directly on a silicon (Si) readout integrated circuit (ROIC). The infrared focal plane array that generates the electrical signals to be converted into a digital picture was directly and monolithically connected to the ROIC that interprets those signals to create a picture, without a need for externally applied contacts and interconnects. This monolithic integration also formed a proof-of-concept for the fabrication of a novel high-efficiency, two-junction and two-terminal solar cell.

T.S. Lee, who joined EPIR from the U. of Illinois/Chicago, noted that several technical hurdles were overcome, including MBE growth of CdTe and HgCdTe layers on heterostructural silicon wafers containing readout ICs to successfully mate II-VI semiconductor materials with Si for device fabrication for x-ray and infrared detection.

Other challenges included cleaning the Si ROICs without damaging the contacts or resorting to temperatures high enough to damage the ROICs; direct deposition of high quality single crystal CdTe directly on the Si ROICs; deposition of high-quality single-crystal MCT on the CdTe and the dopant activation and device processing to create an FPA, all at temperatures low enough not to harm the ROIC.

This and similar work done by EPIR on IR FPAs “has clearly demonstrated the ability to fabricate such solar cells with the necessary current matching and efficient current collection, without a buffer layer between the Si and the CdTe, with or without a thin zinc telluride tunneling barrier as needed for current matching,” the companies claim in a statement.

The material grown and the monolithic devices fabricated showed “excellent” carrier recombination time, and similarly “excellent” dynamic FPA impedance (at the standard 80K operating temperature) of 10(6) Ohm-sq. cm (at zero bias) for growth on Si, and 10(5) Ohm-sq. cm for ROICs. Device operability also was deemed “excellent,” although the companies noted a small fraction of the pixels lost operability during device fabrication.

This workshop will focus on making system level components (chip-to-package interconnections, thin film components conductors, dielectrics, capacitors, resistors, inductors, encapsulants, coatings, power sources, batteries) with nanomaterials enabling a number of commercial applications over the next decade. The workshop will feature keynote speakers from semiconductor companies including Intel and Motorola, followed by technical presentations on these four research topics:

(April 9, 2008) Radfeld, AUSTRIA &#151 EMC3D, an international semiconductor equipment and materials consortium dedicated to the cost-effective development of 3D through silicon via (TSV) interconnects, announced the addition of Datacon Technology to the organization. Datacon, manufacturer of die bonding & sorting equipment will provide high-precision assembly expertise to the consortium.

April 1, 2008 — Trident, a provider of inkjet printhead and ink production for commercial applications, says the design and stainless steel construction of its new 256Jet-D inkjet printhead allow for printing of a wide variety of direct write, printable electronic applications, including printing of traces, contacts, embedded passives and components (resistors, capacitors, inductors, etc.) on printed circuit boards; flexible photovoltaics; fuel cells; batteries; and more.

According to the company, the 256Jet-D revolutionizes digital electronics material printing with its durable design. “Until now inkjet printing for direct write has been limited to R & D labs, partly because most inkjet systems have not been able to handle the corrosive and high viscosity fluids needed for many printable electronic applications,” says Steve Liker, Business Manager at Trident. “The stainless steel 256Jet-D provides this industrial durability and makes inkjet printing a very valuable proposition for printable electronics.”

Whereas previously agglomeration of printing materials during the deposition process meant that printhead nozzles would clog and printheads needed to be discarded and replaced, the nozzle plate of the 256Jet-D can simply be removed, cleaned and reassembled. End users can purchase multiple interchangeable nozzle plates in order to print distinct drop volume sizes with the same printhead. The 256Jet-D is available in two models enabling the printing of two distinct drop volume ranges: 5 – 40 picoliters and 50 – 80 picoliters in size.

The inert stainless steel construction of the 256Jet-D printhead resists the corrosive, aggressive alkaline and acidic materials often used in the deposition of printable electronic components. With the ability to be heated to 70°C and to jet fluids up to 30 cps, the 256Jet-D can print materials with twice as much viscosity as traditional inkjet systems, giving users wider flexibility in material loading and fluid formulation. Its rugged industrial design gives the 256Jet-D printhead an industry-leading lifespan of 90 billion firings.

Along with the 256Jet-D Trident offers a high-performance “Precision Drive Controller” (PDC) which promises to simplify customer integration by providing the electronics and software drive control of each of the printhead’s 256 jets with drop volume precision of plus or minus 2%. The 256Jet-D’s 256 individually controllable jets allow a greater number of drops to be deposited in one area, thereby increasing productivity.

April 1, 2008 — Seven months after public introduction of its Organic Metal Nanofinish, Ormecon International says that mass production of printed circuit boards using the coating has begun. According to Ormecon its first customer for the product began mass production on March 26, 2008 with a small number of boards, but in a continuous mode on a regular daily production basis. The production amount will reach 10,000 ft² per month during April and is expected to increase thereafter, eventually to about 100,000 ft² per month.

Ormecon has installed or is in the process of installing seven lines worldwide, in the USA, China, Germany, Korea, and Canada. More than 55 evaluation projects are ongoing, out of which 14 are with OEMs, six with assemblers, and more than 35 with PCB manufacturers.

The majority of the projects is focussed at replacing ENIG (with “OM Nanofinish Top Grade”) or to reduce the Tin thickness in established Immersion Tin processes (using “OM CSN Nanofinish”). These are the two of the in total four different processes which are part of the Nanofinish process family. The other 2 processes are “Common Grade” and “OM Silver Nanofinish”.

The Nanofinish Top Grade is 55nm thick; it promises a much more powerful oxidation protection and solderability preservation than any other established metallic finish — even though, according to Ormecon, traditional finishes are between 6 and 100 times thicker.

Growth was seen in both the wafer fabrication materials and packaging sectors with increases of 17% ($25B) and 9% ($17B) respectively. Japan continues to dominate worldwide semiconductor materials consumption at 22% share due to its large wafer fab and packaging base. Taiwan has held onto the number
two spot in terms of consumption of semiconductor materials for the past four years driven by strong growth in wafer foundries and packaging subcontractors. The Rest of World region (ROW), which aggregates Singapore, Malaysia, Philippines, other areas of Southeast Asia and smaller global markets, claims the third largest materials market due to packaging materials. The semiconductor materials market in China is growing at the fastest rate given the new capacity coming on-line from a previously small base.

By Fran

(April 1, 2008) BRISTOL, U.K. &#151 As part of DuPont Microcircuit Materials’ (MCM) participation at IDTechEx Printed Electronics Europe, which focuses on thin film and organic electronics, Kerry Adams, Ph.D, market development lead, DuPont, will discuss the company’s developments in inks and imaging for printed electronics. The event will be held at Maritim Hotel and Congress Centre in Dresden, Germany on April 8

April 1, 2008 — /SAN JOSE, CA/ — The global semiconductor materials market grew 14 percent in 2007 and is forecasted to grow over 11 percent in 2008 according to the latest materials forecast from SEMI. While the semiconductor industry grew three percent in 2007 to reach the $256 billion published by the Semiconductor Industry Association (SIA), the global semiconductor materials market grew 14 percent in 2007 to reach a record $42 billion.

Growth was seen in both the wafer fabrication materials and packaging sectors with increases of 17 percent ($25 billion) and nine percent ($17 billion) respectively. Japan continues to dominate worldwide semiconductor materials consumption at 22 percent share due to its large wafer fab and packaging base. Taiwan has held onto the number two spot in terms of consumption of semiconductor materials for the past four years driven by strong growth in wafer foundries and packaging subcontractors. The Rest of World region (ROW), which aggregates Singapore, Malaysia, Philippines, other areas of Southeast Asia, and smaller global markets, claims the third largest materials market due to packaging materials. The semiconductor materials market in China is growing at the fastest rate given the new capacity coming on-line from a previously small base.

“As the semiconductor companies continue to ship record amounts of units, demand for materials is increasing as well,” says Dan Tracy, senior director of Industry Research and Statistics at SEMI. “Heightened demand in addition to the tight supply for various gases, silicon, and the widespread adoption of advanced packaging technologies are resulting in very strong revenue growth for semiconductor materials suppliers.”

The Material Market Data Subscription (MMDS) from SEMI provides current revenue data along with two years of historical data and a three-year forecast. A year subscription includes four quarterly updates for the material segments reports revenue for seven market regions (North America, Europe, ROW, Japan, Taiwan, South Korea, and China). The report also features detailed historical data for silicon shipments and revenues for photoresist, photoresist ancillaries, process gases, and leadframes.

About SEMI

SEMI is a global industry association serving the manufacturing supply chains for the microelectronic, display, and photovoltaic industries. SEMI member companies are the engine of the future, enabling smarter, faster, and more economical products that improve lives. Since 1970, SEMI has been committed to helping members grow more profitably, create new markets, and meet common industry challenges. SEMI maintains offices in Austin, Beijing, Brussels, Hsinchu, Moscow, San Jose, Seoul, Shanghai, Singapore, Tokyo, and Washington, D.C.

Visit www.semi.org

New Product Showcase


April 1, 2008

PRODUCT FOCUS – INTERCONNECT MATERIALS

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Dry Film Photoresist

WBR 2000 Series dry film photoresist material from DuPont Advanced Packaging Lithography, was developed for advanced semiconductor packaging applications, including electroplated solder, photostencil and copper pillar bumping. Unlike liquid resists, these dry film photoresists do not require drying of solvents and can be applied in a single uniform layer across the entire wafer with no edge bead. These properties enable higher productivity and yields, particularly for manufacturers requiring thicker layers, which are reportedly difficult to produce with liquid resists. The WBR 2000 Series is said to deliver improved resolution, speed, and consistent resist thickness across the wafer, as well as simpler processing and a reduced environmental footprint.  Due to its high heat resistance, chemical compatibility, and easy removal, WBR 2000 is suited for multi-purpose use, including in-via and mushroom plating, photo-stenciling and copper pillar metallization. Films are available in 50, 75, 100 and 120-μm thicknesses. DuPont Electronic Technologies, Research Triangle Park, NC www.advpackaging.dupont.com

Materials for Wafer Bumping Applications

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Umicore EPM introduces Microbond Docfish, a product family of wafer bumping materials that includes solder paste, tacky flux and solder spheres. UltrafinePitch paste reportedly demonstrates uniform printing behavior with tight coplanarity. It is available in solvent clean (no clean) and water soluble series. All standard lead-free alloys are available with standard solder powder particle size of type 5, 6, and 7.

Designed to be used in all standard reflow soldering systems, the tacky flux series is adjustable for a variety of customer processes with different activation grades. Available in solvent clean (no-clean) and water-soluble series, it is suitable for printing, dipping, spraying or jetting applications.

Aurora Solder Spheres are microspheres from Duksan Hi-Metal (standard diameter range from 300 μm – 70 μm) fabricated from sophisticated, recently developed, alloys for reportedly excellent drop test and thermal cycling results. All standard lead-free alloys are available. Umicore EPM, Hanau, Germany www.microbond.eu

CSP/BGA Underfill

Hysol FP6200 is a CSP/BGA underfill designed to improve thermal cycling reliability. The material is reworkable, allowing for additional process window and recovery of high-cost substrates and PWBs. The removal procedure for FP6200 involves heating the underfill to approximately 240

By Michael Todd, Ph.D., Shashi Gupta, Ph. D. and James T. Huneke, Ph.D., Henkel Corp.

In today’s packaging industry, traditional single-die designs are being replaced by multi-die configurations that offer increased functionality and performance at a lower cost. According to recent research from SEMI and TechSearch International, stacked-die packages are expected to grow at an average annual growth rate of 12% from 2008 to 2010.1 The potential efficiencies of these package technologies are undeniable, but the manufacturing challenges — particularly in relation to handling and materials considerations — loom large. Current techniques using traditional die-attach pastes do not offer the mechanical support, throughput, and yield advantages that modern die-attach films can provide to ultra-thin wafers.

Die-attach film (DAF) technologies in the form of dicing die-attach films (DDF) and flow-over-wire (FOW) materials have emerged as efficient products for next-generation die stacking applications.

Conventional Die-attach Paste Process

Regardless of the die attach material used – film or paste – the wafer must first be mounted onto dicing tape to secure it during the dicing procedure. Once the wafer has been diced, individual die move on to the placement process. Die stacking using die-attach paste requires more time and equipment than stacking procedures that use DAF. Die-attach paste is dispensed onto the first die in the stack (D1), the second level die (D2) is placed and then the 2-die stack is transferred into the cure oven. This procedure must be repeated for each die in the stack. So, a four-die-stack package would see four dispensing steps and four cure oven trips. After the entire stack is complete and all layers have been cured, the package then moves to wire bonding (Figure 1).


Figure 1. Stacked die process flow using traditional die attach paste materials.
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The ultra-thin die used in modern stacked package applications are difficult to handle, and once removed from the dicing tape for placement, loses any mechanical support provided by the film. So, during the placement process, the thin die may crack and/or curl from the handling stresses induced by the standard process.

Die-attach Film Process Advantages

For high-functionality stacked CSPs, DAF materials offer clear processing, cost, and units per hour (UPH) benefits for packages incorporating multi-die stacks. Currently, two die-attach film materials are delivering promising in-field results —DDF for die stacks incorporating die of varying dimensions and/or configurations where the wire-bonds are completely encapsulated by mold compound, and FOW films for stacking same-size die where wire-bonds are partially in mold compound and partially in film adhesive (Figure 2).


Figure 2. Various stacked die configuration options.
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Dicing Die-attach Film

DDF, which combines both dicing tape and die-attach material into one product, is proving to be a good replacement for die-attach paste. From a performance point of view, DDF offers control of paste bleed, creeping effect to die edge, as well as consistent bondline control (BLT) at the desired thickness. Though earlier generation film materials did not offer the placement speeds delivered by that of die attach pastes, newer DDF formulations enable die placement times that are comparable, if not faster, than die-attach pastes. On average, placement speeds using die-attach pastes are 0.3 seconds. Today’s DDF technology delivers wetting ability with placement times of as little as 0.1 seconds, challenging the throughput argument often used by proponents of die-attach paste.

The most important advantage of DDF materials, however, is the support films offer for thin wafer handling, which allows even thinner die to be used for die-stacking applications. Package die stacks using 75 μm have been achieved, and even 25-μm wafer package die stack is now possible with new die attach film technologies.

When using DDF, the wafer is laminated onto the film then diced, and the die is picked and placed on the stack. Advanced DDF materials do not require any cure step prior to wire bonding – each die in the stack can be picked and placed and then the entire package moves to wire bonding. There are some DDFs that require a UV process to release the dicing tape adhesive from the die-attach, which may add time and process control challenges to the die stacking procedure. Pressure-sensitive DDF materials do away with UV requirements, thus improving throughput and reducing costs by eliminating the need for UV equipment.


Figure 3. Using film for support has clear wafer handling and processing advantages.
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With the performance benefits and critical handling advantages afforded by these materials (Figure 3) DDF is undoubtedly one of the more cost-effective key enablers for modern stacked die packages.

FOW Film

A recent development in die-attach film technology is FOW materials that allow same-size die stacking. FOW film is formulated to incorporate die-attach film and dicing tape into one product. Because these materials are designed to flow over the wire bonds of the die below the one being placed, the need for spacer die or sequential die staggering is eliminated. For no-cure FOW materials, the process is identical to that of DDF. The wafer is laminated onto FOW film, diced, and then the die are picked and placed. The stack moves to wire bonding and then on to molding. While no-cure FOW products are ideal for maximizing UPH, some manufacturers are still more comfortable incorporating a cure step into their die stacking process — particularly for same-size die stacks — as a precautionary step to prevent any die movement during molding. Consequently, two alternative cure materials have been designed to meet the varying requirements of certain applications. The first, a quick-cure FOW (FOW A) offers the ability to cure inline on the wire bonder with no separate oven cure step required, as it can cure within 10 minutes at 175