Terrace Free SOI: maximizing usable wafer area

Terrace Free SOI is available across Okmetic’s 200 mm SOI wafer portfolio, including Bonded SOI (BSOI), Enhanced SOI (E-SOI®), Power Management SOI and High Resistivity SOI wafers. The solution combines increased active area with an edge design optimized for device manufacturing. 

More dies per wafer 

By eliminating the conventional SOI terrace (non-SOI area) found at the wafer edge, Terrace Free SOI provides approximately 4% more active area compared to standard SOI wafers. In addition, the Fixed Quality Area (FQA) increases by approximately 3% due to the reduced edge exclusion, enabling more efficient utilization of the wafer surface and more dies per wafer. This helps device manufacturers maximize the value obtained from each wafer. 

Optimized edge design  

In addition to maximized active area, Terrace Free SOI offers an optimized and customizable edge profile. A precisely controlled front bevel extends to the SOI layer–BOX interface, supporting improved edge characteristics. 

By minimizing the thin silicon overhang that may arise under certain device manufacturing conditions, Terrace Free SOI helps to enhance process robustness and consistency. This enables smoother and more reliable execution of critical manufacturing steps, including bonded wafer stack thinning, epitaxial growth, lithography, dicing, and wafer handling. 

A customer-driven innovation 

Originally developed in close collaboration with customers, Terrace Free SOI has been adopted for a wide range of applications, including MEMS, sensor, RF and power management devices, where maximizing usable wafer area is an important consideration. 

Terrace Free SOI is one of several SOI wafer edge solutions available from Okmetic, giving customers flexibility to select the approach that best fits their device design and manufacturing requirements. 

Okmetic’s Bonded SOI wafer line comprise the following products: 

• Terrace Free SOI capability for BSOI, E-SOI®, Power Management and High Resistivity SOI wafers 

• BSOI wafers - Bonded SOI (including BSOI variations 0.3 SOI, DSOI, LSOI and Thick SOI) 

• E-SOI® wafers – Enhanced SOI with tight thickness uniformity 

• Power Management SOI wafers are part of our Power wafer line 

• High Resistivity BSOI wafers are part of our RFSi®wafer line 

• C-SOI® Wafers– Cavity SOI (including C-SOI® variations EC-SOI, Double C-SOI®, C-SOI® with patterned device layer, C-SOI® with poly via)