During the manufacture of integrated circuits from silicon wafers, the wafers are treated and processed in multiple co-ordinated steps. These steps are performed in sequence at different locations in a fabrication facility that includes a variety of different wafer processing equipment. One known processing step is the heating of a partially fabricated integrated circuit in the presence of a controlled environment to process a wafer. Another such process is the positioning of a wafer within an ion beam for beam treatment of the wafer to selectively dope regions of the wafer. Apparatus for curing silicon wafers and stripping away photoresist are also other known automation tools used in fabricating integrated circuits. These processes are performed without human contact with the wafers. Mechanical devices lift, rotate, transport and gently place the wafers during these multiple co-ordinated processing procedures.
Proper set up of silicon wafer handling devices is important to minimize introduction of contaminants and avoiding damage to wafers due to inadvertent dropping, sliding or scraping of the wafers. Such set up can be difficult to perform when the wafer is located in a vacuum. Visibility and access to obtain physical measurements are limited. As a result, set up may be performed using nothing more sophisticated than a trained eye to look for slight movement, gaps and the like. Such set up is very subjective and inconsistent since there is no clear acceptable range or means to measure this range if it could be defined.
Set up of devices can be affect by exposure to vacuum, making bench set up of fixtures less useful. If the set up is performed without exposure of the treatment chamber to vacuum, then the application of a vacuum after setup can cause the equipment to become misaligned. The vacuum chamber walls move as vacuum is being applied. This can result in a previously aligned fixture becoming out of align as the walls of the chamber move. Bench fixtures that do exist are generic and do not compensate for any part specific tolerances or manufacturing variances. Periodic inspection of the wafer handling devices also needs to occur. A means to verify alignment without requiring venting of the tool (for installation/removal of a test fixture) is a desirable goal to minimize down time and ill effects causes by venting to atmosphere of the workpiece treatment chamber.