K&S gets serious...about saws
04/01/2000
Mark Diorio
For years, Kulicke & Soffa has been the market leader in wire bond technology. From time to time, companies from Japan and Switzerland challenge its market share or technology position but, in the long run, K&S has come out on top. While the company has dabbled in other assembly equipment products, such as die bonders, dicing saws and autolines, its main focus and most effective resources were always applied to the wire bond product sector. Some have joked that if the equipment didn`t have a "W" and "R" in the name (as in wire bonder), K&S didn`t take it seriously.
Now K&S is poised to (re)attack another assembly equipment product sector: the dicing saw. While the semiconductor market size of saws pales in comparison to wire bonder demand, it is growing at an increasing rate. More advanced packages are being sawn or diced rather than punched for singulation purposes. As ball grid array (BGA) and chip scale package (CSP) volumes and applications grow, more effective ways to singulate these package types without jeopardizing their integrity or reliability are needed. Sawing or dicing to singulate many of these package types is a reasonable solution. And, singulation by saw will be a necessity for wafer-level package efforts as well.
K&S recently introduced the Model 7700 Twin that uses a dual spindle design. Unlike other designs, which place the spindles in series or behind each other, this model places the spindles in parallel or facing each other. This allows both blades to cut during a higher percentage of their travel and can provide a higher UPH both in bevel cut and parallel cut modes (results from a UPH simulation model indicate 10 percent and 25 percent increases respectively). The machine design that holds the spindles in place is a bridge-type structure and appears significantly more rigid than typical cantilever structures. While this design aspect is especially important for the long stroke needed to accommodate 300-mm wafers, the increased rigidity of this spindle design can reduce deflection and vibration amplitude and thus improve accuracy and cut quality.
A dual spindle dicing saw allows for a greater degree of processing capabilities. With two spindles, I can affect the silicon stress structure to significantly improve reliability and quality of the packaged device. With package singulation, it is also possible to improve the package interface integrity for the same reasons. I could probably achieve the same result with two separate saws placed in series, but I don`t believe this is cost-effective.
A Pentium III class PC controls the Model 7700. The moving axes and other subsystems are driven by dedicated microprocessors. The distributed control offloads the microprocessing unit from low-level tasks, supporting coordinated simultaneous motions. This, coupled with direct drive linear DC brushless motors with high-resolution encoders, should provide an added degree of accuracy and speed. Competitive machines may offer a straightforward method of programming, but the Windows-like operating system used on the Model 7700 seems more user-friendly.
The Model 7700 has a unique blade monitoring system, which assumes that load variations indicate process deviations and should be reported and analyzed. The 7700 can detect insufficient blade dressing, blade deterioration and cooling problems - important for applications of BGA, CSP and wafer-level singulation, as there is a correlation between blade load and cut quality.
It is not enough, though, to just have an advanced technology machine. Of equal importance are competent people. Moshe Jacobi, general manager of K&S Israel, has put together a team that includes recognized industry experts such as Tommy Weiss and Mark Brown, with about 50 years` combined experience in sawing/dicing technology.
So it looks as if K&S is getting serious about saws. Very serious. But K&S` competition also puts out a good machine and has good people. The ultimate question is : Will K&S provide the same focus and commitment that has let them excel in wire bonders? It`s possible, I suppose - after all, there is a "W" in saw!
MARK DiORIO, chief operating officer, can be contacted at MTBSolutions Inc., 2685 Marine Way, Suite 1220, Mountain View, CA 94043; 650-960-3203; E-mail: [email protected].