System and method for test key characterizing wafer processing state

A method of forming a test structure, comprising:

• forming a plurality of shallow trench isolation structures (STIs) on a substrate of a wafer and in a scribe line of the wafer;
• and
• forming a test key on the substrate of a wafer and in the scribe line of the wafer, the forming the test key comprising:
• forming at least one test key group having a plurality of test key series, each of the plurality of test key series having a plurality of test pads formed from a semiconductor material, a first test pad being epitaxially grown simultaneously with epitaxially growing a first operative structure in a device region of the wafer and being doped simultaneously with the first operative structure so the first test pad and the first operative structure have a first doping profile and a second test pad being epitaxially grown simultaneously with epitaxially growing a second operative structure in the device region of the wafer and being doped simultaneously with the second operative structure so the second test pad and the second operative structure have a second doping profile different than the first doping profile.

A method comprising:

• forming a semiconductor device on a substrate, the substrate including device areas and a scribe line separating the device areas;
• and
• defining a plurality of test pads in the scribe line using a patterned isolation layer;
• epitaxially growing a first epitaxial material in a first test pad, simultaneously with epitaxially growing the first epitaxial material in a device area;
• epitaxially growing a second epitaxial material, different than the first material, in a second test pad, simultaneously with epitaxially growing the second epitaxial material in the device area;
• and
• modifying a doping profile of a region in the device area simultaneously with modifying a doping profile of at least one of the first test pad and the second test pad so that a doping profile of the first test pad differs from a doping profile of the second test pad.