Patent Number: 059230401
Section: summary

This invention relates generally to retaining samples of semiconductor wafers for viewing by electron microscopes such as a scanning electron microscope ("SEM"). BACKGROUND OF THE INVENTION Electron microscopes are used in semiconductor manufacturing operations to enable engineers to view the semiconductor wafers that are populated by features which are too small to visualize. Usually a sample of a disk shaped wafer is formed and an edge of that wafer or other pertinent portion is viewed under the electron microscope. The electron microscope magnifies the features of the sample and allows its configuration to be studied. Scanning electron microscopes are commonly utilized to determine whether features which are formed in the semiconductor wafer correspond to what was designed, intended or most desirable. Traditionally, the samples are secured to an adjustably positionable base in the electron microscope. The base may be connected to a sample holder which actually retains the semiconductor wafer samples. These samples are secured to an upstanding member on the sample holder using copper tape and curable adhesive. Commonly, the curable adhesive must be allowed to dry for several hours before the sample can be studied in the electron microscope. Thus, existing techniques require considerable effort to secure the sample for viewing. Perhaps more importantly, the procedure takes an excessive amount of time, thereby delaying the feedback to the design engineers. Therefore, it would be desirable to provide a technique for readily securing the wafer samples in the hostile environment inside an electron microscope. SUMMARY OF THE INVENTION In accordance with one aspect of the present invention, a wafer sample retainer for an electron microscope includes a base and a sample holder removably connectable to the base. A spring biased member is arranged to contact a wafer sample and to secure the sample against the sample holder. In accordance with another aspect of the present invention, a wafer sample retainer for an electron microscope includes a rail, a base adjustably positionable along the rail, and a sample holder. The sample holder is removably connectable to the base. The sample holder includes an upstanding post. A spring biased member is mounted for pivotal rotation on the holder. The member has a free end pivotable towards and away from the post. In accordance with still another aspect of the present invention, a method of retaining a wafer sample for examination under an electron microscope includes the step of securing a sample retainer to a base. A spring biased arm is biased against the sample to secure the sample between the arm and the retainer. At least certain embodiments of the present invention are advantageous, among other reasons, because they simplify and expedite sample holding in electron microscopes.