Methods for critical dimension and focus mapping using critical dimension test marks

A method for determining the performance of semiconductor wafer processing equipment, the method comprising:

• creating a plurality of test marks on the surface of the semiconductor wafer during a processing step, the test marks being made by an imaging pattern with known critical dimensions;
• measuring the test marks after the processing step is complete;
• and
• adjusting the equipment if the test marks are not measured to have at least a predefined value.

A method for using test marks generated by a lithographic process, the method comprising the steps of:

• selecting areas of a semiconductor wafer, the wafer having a top surface upon which areas test marks will be generated;
• generating the test marks on the selected areas by using a lithographic process;
• measuring at least a first predefined parameter of the test marks;
• and
• altering at least one parameter of the lithographic process depending on the results of the measuring step.

An apparatus for determining the best focus position of a lithographic production device, the apparatus comprising:

• the lithographic production device for creating a plurality of test fields in a resist formed on a wafer, wherein each test field has a multiplicity of test marks that are formed using incrementally different focuses of the lithographic device such that the marks within each field are stepped through focus, the test fields being distributed at different locations about the wafer with some test fields being located at the edge of a useful portion of the wafer and some of the test fields being located at interior positions on the wafer;
• a measuring system for measuring each of the test marks at each of the plurality of focus steps;
• and
• a data collection device coupled to the measuring system for storing the results of the measurement of the test marks and for calculating from the stored measurements the best focus position of the lithographic production device.

A method for determining the best focus position of a lithographic production device, the method comprising the steps of:

• creating a plurality of test marks across a surface of a wafer at a first focus position;
• stepping the focus position to a successive focus position;
• repeating the creating and stepping operations until a plurality of test marks has been created on the wafer at a predefined plurality of focus steps;
• measuring each plurality of test marks at each f the plurality of focus steps;
• selecting the focus step for future operation of the lithographic production device that created test marks having the largest measure value.