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Performance of Second 50 Completed ATP Projects — Status Report Number 3 NIST Special Publication 950-3 (January 2006)
Ink-Jet Printing Technology To Connect Microelectronic Components MicroFab Technologies, Inc., a small company based in Plano, Texas, was founded in 1984 by an expert in ink-jet printing technology. In 1994, the company received $1.6 million in funding from the Advanced Technology Program (ATP) to apply its ink-jetting methods in a novel way to disperse molten metal solder drops to attach semiconductor chips to circuit boards. The resulting technology can produce droplets as small as 40 microns across (about half the width of a human hair). No other technique had been able to establish sizes this small. The size of the droplets allows more information to be packed into less space, with far more control over the process. In addition, jet-based solder equipment can produce and place molten solder droplets at rates up to 2,000 droplets per second. MicroFab's method "writes" the solder patterns on circuit boards at high temperatures using an ink-jet printer. The technique is unique in its ability to write solder lines and achieve line density four times that of traditional lithography methods. MicroFab Explores Two Methods To Generate Solder Streams
During the ATP project, MicroFab explored continuous and drop-on-demand methods for generating solder streams. In the continuous method, the liquid solder goes through a charging electrode system that creates pressure oscillations of constant frequency that break up the solder stream into uniform droplets and can produce thousands of solder droplets per second. A disadvantage of this method is that unused drops are produced that must be recycled or discarded, which raises an environmental concern. The drop-on-demand solder method uses a reservoir of fluid that is acted on by a force, which causes it to eject droplets in a discrete volume. It is a slower process that has the advantage of generating no excess droplets that must be discarded. MicroFab selected the drop-on-demand method for its ink-jet soldering because this method avoided the environmental concerns of the continuous method. Ink-jet solder deposition is a low-cost alternative to traditional soldering methods because no masks or screens are required. It is flexible because images are formed and stored digitally, and it is highly repeatable at differing resolutions. It lends itself to customization and reworking. Because ink-jet soldering is driven by computer-assisted design, it provides more flexibility in the types of patterns that can be created and the variety of applications for which it can be used. The solder-jet technology can produce droplets assmall as 40 microns across Real-time process control is possible because the depositions can be inspected immediately after the process, thus reducing prototyping and development time. This represents a major improvement over other less flexible methods. Consortium Formed to Test Prototypes During the time that MicroFab collaborated with ATP, the company also entered into a consortium with high-end original equipment manufacturers, which represented the potential end users of this technology. These manufacturers, including Motorola, Delco, Texas Instruments, Kodak, and AMP, received prototype machines that used the solder-jet technology, tested them, and provided feedback to MicroFab as development proceeded. The ATP award helped MicroFab to collaborate with and attract additional funding Accordingly, the requirements of the technology were more quickly and accurately defined, and MicroFab was able to more easily and accurately configure the machines to implement the technology. These relationships also had the potential to improve the ultimate diffusion of the technology. MicroFab Leverages Solder Jet Technology The development of solder jet technology enabled MicroFab to create other viable technologies as well. In its own production, it applies the drop-on-demand process it developed during the project. MicroFab uses the solder jet technology in its its Jetlab® platform, which has a selling price of approximately $200,000. The Jetlab® platform is a tool for a variety of industries—including microelectronics, photonics, medical diagnostics, and drug delivery—to identify jetting processes and fluids that best meet their specific needs. In addition, MicroFab sells fluids designed for micro-optic and microelectronic applications. It also supplies printhead subsystems using the ATP funded technology. Conclusion Many were skeptical of MicroFab's proposed process. In fact, major players in the industry said that it could not be done. Such skepticism reflected the highly risky nature of the venture. Private capital was unavailable to the company in order to pursue development of the technology. Without ATP's help, MicroFab would have had great difficulty in proceeding with its concept. In the words of MicroFab's research director David Wallace, "We'd done some preliminary technical work and feasibility studies to show our concept's viability, but it was at a stage where it was far too risky to get venture capital or investments from large end-user companies that would be beneficiaries of the technology." ATP's backing also gave other major players in the industry the confidence to test the new process. The ATP award helped MicroFab to collaborate with and attract additional funding from a consortium of five major electronics manufacturers to further develop its technology. MicroFab continues to work with these manufacturers and other end users to develop and refine the technology.
Research and data for Status Report 93-01-0183 were collected during October - December 2001. Return to Table of Contents or go to next section of Status Report No. 3. Date created: April 4, 2006 |
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ATP website comments: webmaster-atp@nist.gov / Technical ATP inquiries: InfoCoord.ATP@nist.gov. NIST is an agency of the U.S. Commerce Department |
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