Inside AMD - Touring Fab 30

Welcome to the Materials Analysis Labs

Once the defective wafers are prepared in the Sample Preparation Lab they are sent to the Materials Analysis Labs where the actual analysis begins.

To give you an idea of the sensitivity of the equipment used in the Materials Analysis Labs, AMD had to build the entire set of Labs on a separate slab of concrete at Fab 30; the reason for this was to prevent minute vibrations from the rest of the facility to make their way into the Materials Analysis Labs (MALabs). The tools used in the MALabs are used for looking at pieces of silicon at atomic levels; any foreign vibrations could seriously impact the accuracy of the equipment.

The first part of the MALabs we walked through was the Transmission Electron Microscopy Lab – home to AMD’s highest resolution microscope. This lab is able to use a number of multimillion dollar microscopes to see individual Silicon atoms. The lab is quite useful in seeing differences in very thin layers such as the gate oxide in transistors. To give you an idea of how thin the gate oxide of current generation transistors happens to be, we’re talking about a thickness of around 1.2nm or approximately 5 atoms.

The purpose of these powerful microscopes is to more closely investigate defects in areas such as the gate oxide and thus can be used to improve the manufacturing processes.

Our next stop took us into the Scanning Electron Microscopy Lab, which is yet another high powered microscope lab but this time it is more focused on checking the dimensions of structures to make sure the manufacturing tools are in specification. The purpose of the Scanning Electron Microscopy Lab is to analyze defects, which was the major theme behind our tour at Fab 30. The tools within this lab can scan entire 8” wafers that are produced in the fab, once again mostly test structures.

One test that is run in the Scanning Electron Microscopy Lab is for Electron BackScatter Diffraction (EBSD) patterns. The way the test works is relatively simple in principle; a machine will bombard a copper interconnect line with electrons, and the diffraction pattern that results from the electrons bouncing off the line will give an indication of the grain of the copper. Over the past couple of days in Dresden we become intimately familiar with the importance of the grain of the copper wires to the reliability and performance of AMD’s processors.