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Automated Vision Will Play a Critical Part of Semiconductor Rebound
by Winn Hardin, Contributing Editor - AIA Posted 09/17/2002
Shrinking critical dimensions, new materials and transistor designs, larger wafers and new IC packages are driving the performance of microchips to new heights. Performance improvements do not come cheap, however. As a result, in-line automated visual inspection of each step in the IC fabrication process is more important today than ever. IC fabs use vision inspection in more locations per machine, and within more machines today than ever before - and experts agree that the number of inspection nodes will continue to grow as new process and packaging technologies come on line.
IC industry takes a breath
In the late 1990s, the semiconductor industry drove the tech boom as consumer electronics manufacturers strove to keep shelves stocked against staggering demand. To newcomers the two year slump in IC production may seem like the end of the world coming as it did on the tail of monstrous growth. But the truth is that the semiconductor industry is cycle, and like Christmas, it will come around again.
As pundits worry over the future of ICs - citing physical limitations on critical dimensions - designers are already bringing new technologies to bear that will support ever smaller and faster chips. Intel has put its terahertz transistor resplendent with high-K dielectric materials squarely in the cross hairs of the next generation of ICs. IBM, AMD, Intel and others are championing faster copper interconnects and all the while the galloping microchip horde moves closer to 300 mm wafers -bigger baskets to hold greater numbers of silicon nuggets.
Unfortunately, everything has yet to come together. But while Wall Street wrings its hands, unable to see the forest for the trees, the semiconductor industry is moving towards another boom. When these technologies come out of qualification with full heads of steam, a spending public likely will be hungry for the newest batch of electronic toys. 'The market has been relatively depressed through 2001,' reflected Cognex's (Natick, MA) senior vice president of marketing, Justin Testa. 'We saw some upward trending this year, but there's some stalling taking place. In general, though, the prognosis is very good and we're still very bullish on [the semiconductor] industry…All the trends we've identified point towards increased use of vision.'
MV changes 2D inspection to meet industry economics
As with most market downturns, sales of GPMV have taken a dip. In response, MV suppliers to the semiconductor industry have taken this opportunity to redesign traditional equipment used for commonplace automated inspection tasks, such as alignment, OCR, first pin (or notch) identification to offer greater functionality in smaller packages at less cost per inspection than previous systems.
While most major vision suppliers to the semiconductor industry have announced consolidated or enhanced components targeting the COTS 2D inspection niche, the major manufacturers are taking different paths to next-gen 2D inspection. According to PPT Vision's president Joe Christenson, revolutionary changes to 2D IC inspection are difficult to achieve based on the maturity of the systems. Rather, success depends on finding the right mix of functionality, ease of use and cost. PPT Vision's new modular Impact series of all digital inspection systems combine a single board computer with IBM PowerPC chip and Ethernet compatible camera into a single, expandable modular system. 'The 2D systems in semiconductor are bifurcating into PC-based versus smart cameras. We think the unique way we've combined the technologies with the price point we're putting it at will be very competitive,' Christenson said. Inspection protocols can easily be downloaded over the LAN with Impact. Communication and control will be further enhanced in the next version which will move from PPT's proprietary DSL camera interface to a CameraLink standard.
The maturity of 2D inspection algorithms means that MV suppliers must focus on price, footprint and ease of integration when serving the semiconductor industry to differentiate themselves. Robotic Vision Systems Inc. (RVSI, Canton, MA) is adding a quickset feature with associated hardware to make integration and set up nearly as easy as plugging in a lamp. The Hawkeye 15E embedded vision system comes complete with optics, camera, processor, I/O and Ethernet capability, but also with a targeting laser, embedded illumination and 'quickset' button. By putting the laser point exactly on the target area, and hitting the quickset button, the camera essentially self trains itself for data matrix location and identification. The system does not require a PC for set up and training, although it is an option if the integrator wants to tweak the inspection protocol.
More vision, more dimensions, in less space
Embedded vision will enable more inspection nodes along the fab process, but some times more image processing functions are more than a smart camera can handle. Tracking individual wafers during the lithographic process is one area where the need for more camera inspection stops translates to a higher bandwidth and a need for more processing power. 'Customers are telling us that as they move into 300 mm, they will have to track each wafer rather than just batches. Not all customers were doing that before. When a single wafer represents a couple hundred thousand dollars, you need real-time process controls to improve yields,' said Cognex's Testa.
RVSI is one supplier that is boosting the processing capabilities of its image processing engine boards to accommodate this trend without impacting the size and shape of the lithographic steppers, deposition systems and etchers. 'With the 4000, the latest generation of our Visionscape family,' said Chief Technology officer of RVSI's Acuity CiMatrix division, John Agapakis, 'you can off-load all the vision processing away from the PC machine controller. You don't want to stack PCs as you add more cameras and inspection tasks. Semiconductor manufacturers can plug in multiple boards with this type of configuration with zero footprint - and that's what our OEM customers prefer.'
While MV has not typically been a bottleneck for semiconductor inspection, emerging no lead packages such as ball grid array (BGA), column grid array (CGA), and other chip scale packages with high I/O port counts are challenging companies to boost resolution while meeting in-line production speeds. RVSI has added vision to its enhanced speed WS laser triangulation system in order to meet all the 2D tracking and visual inspection criteria while providing sub-micron coplanarity measurements for bump bond interconnects. PPT Vision has added a 3D arm to its business, adopting a scanning moiré interferometry (SMI) 861 system for chip scale package inspection on the strip. 'The market is shifting from leaded to bump bonding, and processing to strip from singulation. Those things coming together are creating a demand for high-speed 3D coplanarity inspection.'
Interest from OEM equipment manufacturers in the semiconductor industry will continue to support the development of new vision technologies such as in-line 3D inspection. Recently, PPT Vision announced an agreement with Electroglas Inc. (San Jose, CA) to adapt its 3D measurement sensor head for package inspection to a wafer-scale inspection system. 'The projection is the same, but the optics have to be improved to get to the wafer level,' said PPT's Christenson. As the industry continues to adopt new expensive high-K dielectric materials and advanced IC packages, the need for reliable automated vision will continue to insure that the MV industry will rise on the success of its largest patron and most powerful ally -- the semiconductor industry.
Companies mentioned in this article:
One Vision Drive
Natick, MA 01760-2059
Main: (508) 650-3000
Customer Technical Support: (508) 650-6300
Investor Literature Request Line (voice mail): (508) 650-3377
PPT VISION, Inc.
12988 Valley View Road
Eden Prairie, MN 55344
Robotic Vision Systems Inc.
5 Shawmut Road
Canton, MA 02021
781 302 2439
800 646 6664 (USA Only)
6024 Silver Creek Valley Road
San Jose, CA 95138
Main # 408-528-3000
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