Takano vs. Surfscan: Choosing the Right Metrology Tool for Advanced Substrate Inspection

Selecting the right inspection tool is critical. Fabs that are replacing aging equipment, or actively expanding their particle inspection capabilities, or even just starting to consider particle inspection for quality improvements are frequently comparing: the KLA-Tencor Surfscan 6000 against the Takano WM-7SR particle scan systems.

Both manufacturers' systems are effective for particle scans on bare and filmed wafers, but they have different strengths and weaknesses. This article helps fab engineers and purchasing teams understand the trade-offs—and decide which is the better fit for their process goals.

Particle Scanning for Wafers 200mm or Smaller

Surfscan 6000 Series

KLA-Tencor has dominated the particle scan market since the early 1990s. Thousands of Surfscan 6000 series machines including: 6100, 6200, 6220, 6400 & 6420 models were sold, and many of them are still in use today. The Surfscan 6000 systems utilize a 30mW gas laser whose beam is oscillated to raster scan across a wafer. They are capable of detecting particles as small as 204nm. The Surfscan 6100 and 62x0 models illuminate the wafer surface with a fixed normal incident angle beam which excels at scanning smooth surfaces and gathering haze data. The Surfscan 64x0 system design uses a different oblique incident angle which is capable of gathering particle data on smooth or rough surfaces such as polysilicon and metals.

The Surfscan 6000 series systems are now 20-30 years old which has some unique advantages and disadvantages.

Takano WM-7 Series

Takano WM-7 Series machines including the WM-7, WM-7S, & the new WM-7SR have dominated the Japanese market for particle scan systems, and Takanos are now propagating worldwide. The modern Takano WM-7SR utilizes a variable power laser diode that is fixed at an oblique incident angle. The scattered laser light is collected with dual photomultiplier tubes (PMTs). In the Takano system wafers spin on a moving vacuum chuck while the laser beam is stationary. Takano WM-7SR systems are capable of detecting particles as small as 61nm and can measure smooth and rough surface conditions.

Which Particle Inspection System to Choose?

Both refurbished Surfscan systems and new Takano WM-7SR systems can deliver excellent particle scanning performance. The correct selection will depend on your fab's particle sensitivity requirement, budget, down-time tolerance, need for precision haze measurements, data export expectations, IT requirements, and other factors. New Takano systems offer excellent performance with a low COO, however refurbished Surfscan 6000 systems offer well recognized legacy results.

At ClassOne Equipment, all new and refurbished tools include installation support, warranty coverage, optional service contracts, and documentation to support quality assurance.

ClassOne Equipment has handled the refurbishment and support of KLA Surfscan systems for over 15 years and has installed hundreds of these systems worldwide. In recent years, ClassOne Equipment has become the exclusive distributor for Takano WM Systems for North America and Europe. If you are interested in advanced particle inspection systems, we would be happy to speak with you about your specific measurement challenges to identify the equipment that will best fit your needs. Contact us today!