System for using test structures to evaluate a fabrication of a wafer
A system is provided for using test structures to evaluate a fabrication of a wafer. The test structures include a combination of device and interconnect elements that are provided on an active region of a die, on the wafer prior to the fabrication of the wafer being completed. The combination of device and interconnect elements include one or more circuits that are activatable to produce an output corresponding to measurable electrical and/or optical characteristics. A power receiving element that is configured to receive activation energy sufficient to cause the output on a contactless medium, so that the activation energy is received without affecting a usability of the die or wafer. The one or more circuits are structured to generate a variation in either the output or in a parameter determined from output, as a result of a process variation in a specific fabrication step that provided elements for forming the one or more circuits. A detector is provided to detect the output over the contactless medium, so as to receive the output without affecting a usability of the wafer when fabrication is completed.
1. A system for evaluating a fabrication of a wafer that includes one or more die, the system comprising:
one or more test structures that each comprise:
a combination of device and interconnect elements that are provided on an active region of a die on the wafer prior to the fabrication of the wafer being completed, the combination of device and interconnect elements including one or more circuits that are activatable to produce an output corresponding to measurable electrical and/or optical characteristics;
includes a power receiving element that is configured to receive activation energy sufficient to cause the output on a contactless medium;
wherein the one or more circuits are structured to generate a variation in either the output or in a parameter determined from output, as a result of a process variation in a specific fabrication step that provided elements for forming the one or more circuits;
a detector to detect the output over the contactless medium, so as to receive the output without affecting a usability of the wafer when fabrication is completed.
2. The system of claim 1 , wherein the output of one or more of the plurality of test structures includes at least one of an electrostatic, electromagnetic, or inductive signal that is created by an output of each of the one or more test structures in response to being triggered.
3. The system of claim 1 , wherein the output of one or more of the plurality of test structures is a radio-frequency output that has a characteristic that identifies the test structure from other test structures.
4. The system of claim 1 , wherein the of device and interconnect elements of one or more of the plurality of test structures includes a plurality of transistors.
5. The system of claim 1 , wherein the plurality of test structures are configured to be concurrently.
6. The system of claim 5 , wherein the output from at least some of the plurality of test structures identify those test structures from other test structures on the wafer.
7. The system of claim 1 , wherein each of the plurality of test structures are at least partially tiggerable by a common energy beam.
8. The system of claim 7 , wherein the electrical activity of one or more of the plurality of test structures includes photons produced from a switch element in the combination of device and interconnect elements of the one or more test structures.
9. The system of claim 1 , wherein the of device and interconnect elements of one or more of the plurality of test structures includes a plurality of interconnected inverters.
10. The system of claim 9 , wherein the of device and interconnect elements of one or more of the plurality of test structures includes one or more CMOS inverters.