Ion-Beam Gas Chemistry

The company offers a new Delineation Etch gas chemistry for their DualBeam systems to delineate oxide layers in SEM images of FIB-milled cross-sections. It addresses semiconductor manufacturers' need to see clearly and measure the many, subtly different layers that compose a typical microelectronic device. With the addition of Delineation Etch, the company's DualBeam tools can precisely locate an area of interest, automatically ion-mill a cross-section, gas-etch the exposed surface to delineate layers, and acquire a high resolution SEM image of the revealed structure, using a single automated system. DualBeam Delineation Etch offers the dame quality of result as conventional, laboratory-based, wet-etched preparations but does so in a self-contained, fab-compatible system, in a fraction of the time, and without destroying the wafer or removing it from the fab environment.

Until now, achieving effective layer delineation has required a laborious, time consuming, and often unreliable manual preparation- cleaving the entire wafer, polishing the fractured surface to reveal the feature of interest, and then wet-etching the surface to delineate layers. Delineation Etch works in conjunction with the ion-beam within the FIB/SEM sample chamber, etching different materials at different rates depending on material consumption and deposition conditions. The topographic relief created between layers by this differential etching is highly visible in SEM images. The DualBeam's automated, five-axis stage permits fast, accurate navigation to specific features and defects that would be difficult or impossible to locate manually, and its sophisticated automation eliminates much of the tedium and opportunity for error associated with manual procedures. With Delineation Etch the speed, reliability and productivity of the sample preparation process all improve dramatically.

The Delineation Etch gas chemistry also provides a powerful new deprocessing capability. In the presence of the ion-beam the gas rapidly etches insulating materials, particularly oxides, but does not spontaneously attack silicon or polysilicon. Used with a simple top-down scan, it can quickly reveal the polysilicon skeleton of a circuit or expose, without damage, a transistor's active regions.

Unlike xenon difluoride, the proprietary gas used by Delineation Etch does not require special handling techniques. It is also non-corrosive to copper, making it ideal for copper technologies. The gas is contained in a standard injector that can be retrofitted on all of the company's 200mm DualBeam and single beam FIB systems.

FEI Company, 7451 N.W. Evergreen Pkwy., Hillsboro, OR 97124-5830. Tel: 503-640-7500. Fax: 503-640-7509.