Integrated Optoelectronic Manufacturing Project Completed
Peter Singer, Editor-in-Chief -- Semiconductor International, 3/1/2001
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Optical fibers, with their huge data-transfer capacities, are becoming pervasive in telecommunications and getting ever closer to the consumer's front door. But the manufacture of critical, high-performance optoelectronic components — those that convert electrons to photons and back again — still generally relies on costly manual assembly techniques. With support from a 1998 ATP award, Digital Optics has developed a new suite of manufacturing techniques for making complex optoelectronic modules.
In an integrated micro-optical subassembly (IMOS) — what Digital Optics calls the Photonic Chip — passive components (such as lenses and mirrors) are fabricated on wafers using photolithography. Complex optical assemblies are built up through wafer-to-wafer bonding (stacking several wafers together), and flip-chip techniques are used to add active components such as lasers and other electronic elements. The approach allows the company to fabricate quite complex optoelectronic modules without costly manual assembly of individual components or the need to precisely align and adjust the components of each module individually.
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In December 1999, Digital Optics partnered with Agilent Technologies Inc. and MicroE Systems Corp. for support in the development of demonstrator modules and for assistance in providing system-level integration and testing of the Photonic Chip. The demonstrator with Agilent aimed to create a potential next-generation platform for transmitter, receiver and transceiver modules for short-reach data communication applications. The demonstrator with MicroE Systems involved a highly integrated sensor module platform.
Initial application of the technology is expected to be in devices for short-range data communications and highly integrated sensor modules. Applications include integrated optical subassemblies for DWDM, CWDM, terabit routers, OEO and all-optical switches, optical interconnects, and other telecom and datacom applications.
New Technique Could Improve Etch Productivity
If you've ever had to shut down an etch system to open it up and clean out the residue that builds up on the chamber walls, help is on the way. Researchers at Hitachi have developed an experimental instrument for quickly analyzing chamber residues using infrared reflection absorption (IRA) spectroscopy. IRA spectroscopy, combined with quadrupole mass spectroscopy of incident ions and molecules, allowed them to analyze chamber residue on a quartz surface. They found that, in the commonly used aluminum etch process, where Al and resist are etched by a plasma fed by Cl2 and BCl3 gases, the residue that built up on the quartz was mostly made of B2O3. This residue is formed by incident boron chloride ions that diffuse through the B2O3 residue to the quartz surface, where it thermally reacted with OH in the quartz. The researchers believe the technique could be used to improve residue control, thereby increasing the mean time between cleans and boosting etch productivity. The work was reported in the January/February 2001 issue of the Journal of Vacuum Science & Technology A.
Microphotonics Web Site Updated
The Web site of the Massachusetts Institute of Technology's Microphotonics Center — where the on-chip optical interconnect research reported in last month's column is underway — was recently updated. Now you can download an informative brochure titled "Bringing New Technology to Light," as well as information about the center, microphotonic roadmapping activities, upcoming seminars and more. Go to http://web.mit.edu/mphotonics/www.
For additional information on wafer processing, go to www.semiconductor.net/wafer
