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By Ron Iscoff, Editor
Singulating a strip of packaged devices by sawing is certainly not a glamorous job, but it's well on the way to becoming one of the most automated and integrated backend tasks. Consider that virtually every vendor of singulation gear now delivers machines with pattern recognition standard or as a basic option. Furthermore, singulation equipment is becoming more modular-and to borrow from computerese-more multitasking. What else? More automation coupled with integration of other, formerly separate functions has become the order of the day. Several vendors have incorporated handlers into their singulation systems for greater throughput. System Integration "Integrating a handling system with a (singulation system) and having them operate as a single unit has been the biggest challenge we've faced," said Robert M. Landry, vice president of sales and marketing for Industrial Tools Inc., Oxnard, Calif. Landry claims to have solved that conundrum with the design of the company's ITI-2000 (Figure 1), which also employs an "open architecture" in its software. The system can also be operated as a stand-alone singulating saw with manual load/ unload or automatic load/unload. Other benefits, says Landry, are the ITI-2000's very high throughput, high-speed parts positioning, no exposed bellows and huge scrap basin for debris. Another supplier, one relatively new to singulation equipment, is MCT of St. Paul, Minn. MCT's Brad Reynolds, product sales director, says the company has "solved productivity and sorting problems" common to very dense CSP arrays with its recently introduced unit. (Dense arrays are defined as 250-1,000 parts/strip). Intelligent Sorting The MCT system (Figure 2) employs a dual spindle, gang blade saw that can produce up to 30,000 singulated devices/ hour. That output is matched to a gang transfer method which uses a high-speed robot that sorts intelligently, based on an electronic strip map.
MCT's system also employs parallel operation, where the singulation involves gang cutting using dual arbors which are preset with the number and spacing of blades in both X and Y directions. Additionally, fiducials are used for vision alignment prior to cutting and for verification post-cut. Productivity, adds Reynolds, is further enhanced because the unit removes the contents of a high-density strip in one motion, allowing the next strip to be set in place for alignment and the next cutting cycle. CSP Density Bill Abeyta of manufacturer MTI, Ventura, Calif., also views growing CSP density as a substantial challenge. As CSP sizes increase due to smaller packages and larger strip formats, unattended operation at high speeds will rely heavily on the interdependence between the system, saw blade and process, according to Abeyta. Equipment design considerations, he adds, "will include not only minimal manufacturing leadtimes, but the ability to adjust for array bow, warp and cutting forces above preset control limits-all without operator intervention." Abeyta claims the MTI NSX-250DS CSP Singulation System, with rigidly structured dual spindles (Figure 3), accommodates up 15 diamond blades/ spindle, enabling it to dice rectangular and square package formats in five passes or less.
What do users look for? "Ask 10 people and you'll get 10 different answers," says Kelly McKendrick Sr., Amkor Technology Inc., Chandler, Ariz. McKendrick, though, wants the following:
Sharam Mostafazadeh, principal product engineer, Analog Operations at National Semiconductor Inc., Santa Clara, Calif., also points to accuracy and flexibility as key attributes.
Coolant Flow Mostafazadeh also looks for monitoring features for consistent coolant flow and for blade condition. Reliability, ease-of-programming, low-maintenance and high throughput are also required features. "The realtime monitoring features, such as coolant flow and blade condition can direcly affect the quality and yield," he notes. "Inconsistent coolant flow can degrade cut quality and reduce the life of the saw blade. Realtime blade monitoring can prevent or reduce chipping and low-quality cuts." Disco, an old-line Japanese company, is a major supplier of dicing saws, which many OEMs integrate into their singulation systems (Figure 4). Chris Winkler, dicing products group leader at Disco Hi-Tec America, Santa Clara, Calif., feels that the current lack of standards in CSPs is forcing suppliers to change current systems and create new equipment to meet the specialized needs of individual users. "This time and expense is detracting from equipment makers' ability to focus their efforts on designing and building new equipment with greater capabilities and efficiencies for the CSP market," Winkler contends. Given the rapid market shifts in substrate type, size and products, standardization would also enable equipment providers to respond to market changes with the proper equipment in a more timely manner, he adds. Kulicke & Soffa recently introduced the 7100 series of dicing saws, offering two separate models for different applications, based on single-spindle, precision dicing technology (Figure 5). A blade-load monitoring system on the units provides a realtime view into the blade to material interaction by monitoring for load patterns that indicate a deviation in cut quality. What Do Users Want? But to repeat our earlier questions, "What do users want?" Amkor's Kelly McKendrick thinks there's another important ingredient that's too often missing: "I want a company that will work with me and that has a vision of the future. "I've had too many people and vendors say that something can't be done or just don't want to put the effort into making things happen. If we didn't have a vision, we would still be making PDIPs with manual equipment."
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