Unpatterned Wafer Surface Inspection Systems
Available in 450mm, 300mm, and 300mm/450mm bridge tool configurations, the Surfscan® SP3 unpatterned wafer inspection tool utilizes deep ultra-violet (DUV) sensitivity and a throughput up to three times that of its predecessor to reliably detect critical defects and surface quality issues for IC, OEM and substrate manufacturing at the 2Xnm design node. The Surfscan SP3 can provide higher sensitivity on bare wafers and blanket films than that of the previous-generation Surfscan SP2/SP2XP. Alternatively, the Surfscan SP3 can operate at a sensitivity similar to that of the Surfscan SP2/SP2XP, but much higher throughput, enabling increased sampling for a lower cost of ownership. The tool also includes an integrated, high resolution SURFmonitor module that characterizes and measures surface quality, helping wafer manufacturers deliver substrates with superior surface quality and chipmakers measure surface roughness and detect subtle defects.
Integrated SURFmonitor is a defect/metrology module that utilizes background scattering (haze) data from Surfscan SP3 scans to monitor process signatures and low contrast defects, without affecting inspection throughput. SURFmonitor can correlate haze to process parameters such as surface roughness and grain size, serving as a high speed, full-wafer metrology proxy for bare wafers and blanket films.
Process Tool Monitoring: Within the IC fab, the Surfscan SP3 is used for qualification and monitoring of process tools for the 2Xnm design node. The DUV sensitivity and enhanced throughput produce high sensitivity to blanket film defects at production speeds, enabling engineers to monitor process tools for defects that may be introduced during film deposition or CMP. In addition, the integrated SURFmonitor allows monitoring of grain size and roughness of copper, tungsten and aluminum films and enables detection of faint or shallow scratches at CMP.
Lithography: With its unique DUV sensitivity, the Surfscan SP3 detects defocus, resist streak and other critical issues when serving as a lithography process tool monitor. In addition, the backside inspection module of the Surfscan SP3 is used within the lithography cell to detect critical backside defects that can cause defocus issues on the front side of the wafer during patterning. The Surfscan SP3’s integrated SURFmonitor module also helps engineers qualify immersion scanners by detecting immersion-unique defects such as water marks.
Incoming Wafer Qualification: The DUV-sensitivity of the Surfscan SP3 helps IC manufacturers ensure that incoming wafers meet their strict quality specifications.
Inline Process Control: Defects that can form during wafer processing (i.e. polish marks, crystalline pits, terracing, voids) can affect the performance of IC devices. Identifying these defects early in the manufacturing process enables improved substrate quality and higher yield. The Surfscan SP3 has the sensitivity and throughput to reliability detect critical defects and surface quality issues inline, helping wafer manufacturers produce the top-grade substrates required for 2Xnm IC devices.
Final Wafer Qualification: The Surfscan SP3 can be used by wafer manufacturers for final qualification of traditional and engineered substrates. While the high throughput of the Surfscan SP3 provides increased productivity for final wafer check, the inspector’s high sensitivity ensures that the wafers meet IC manufacturers’ strict quality specifications.
Process tool qualification: Defects added by the tool during processing, such as fall-on particles or metal contamination, may adversely impact the wafer yield or device performance. Certain process steps like polishing can worsen the wafer surface quality and create anomalous process defect signatures that may render the wafer unsuitable for further processing. Early detection and classification of these subtle conditions is critical to ensure optimal yield. The Surfscan SP3’s DUV defect maps and high-resolution DUV SURFimages provide key information, enabling equipment vendors to build process tools that can reliably handle 450mm wafers.
Process uniformity monitor: The full-wafer high-resolution SURFimage represents the variations of the wafer surface quality in response to changes in process chemistries or recipes, enabling process optimization and production monitoring. Dark field haze calibration ensures that the haze readings are accurate and repeatable across tools.