Manufacturing of integrated circuits and other microdevices involves a variety of process steps that are performed in various machines. A thin slice of semiconductor material (a wafer) is typically moved or handed off between the different machines using a robotic wafer handler. Components of the robotic wafer handler may become misaligned due to component wear or accidental human interference. For example, a 0.1 degree tilt on a component of the wafer handler may result in a robotic arm scratching the wafer during handling.
Scratched wafers are typically discarded, resulting in lost tool time and materials. Furthermore, a typical wafer processing sequence may not detect the scratch until several process steps later when the wafer is examined. During the several process steps hundreds of wafers may have already been scratched by the misaligned tool.
Additional steps may be added to check whether a tool is scratching. The additional steps are typically performed on a weekly basis using wafers and a defect tool. These steps cost cycle time and wafers, and may still result in undetected scratches for a period of time. During the period of scratching, thousands of wafers may be scratched. Increasing the frequency of the additional steps causes even more tool time to be lost.
Accordingly, it is desirable to provide a system and method for monitoring wafer handling for potential wafer scratches. In addition, it is desirable to provide an improved wafer handling machine. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings, brief summary, and this background.