System, method, and medium for an endpoint detection scheme for copper low-dielectric damascene structures for improved dielectric and copper loss

A method of detecting a transition interface between a first dielectric material and an adjacent second dielectric material on a semiconductor wafer during a polishing process, the method comprising:

• initiating the polishing process, said polishing process being implemented to remove the first dielectric material and expose the second dielectric material of the semiconductor wafer;
• impinging an incident light of at least one predetermined wavelength on the semiconductor wafer;
• detecting at least one first intensity of said incident light reflected from the semiconductor wafer at a first time;
• detecting at least one second intensity of said incident light reflected from the semiconductor wafer at a second time;
• determining a difference between the at least one first intensity and the at least one second intensity;
• and
• providing a signal when the difference between the at least one first intensity and the at least one second intensity is above a predetermined threshold, wherein the signal indicates that the transition interface has been detected.

A computer-readable medium of instructions for detecting a transition interface between a first dielectric and an adjacent second dielectric in a semiconductor wafer during a polishing process, the instructions for controlling:

• initiating the polishing process, said polishing process being implemented to remove the first dielectric material and expose the second dielectric material of the semiconductor wafer;
• impinging an incident light of at least one predetermined wavelength on the semiconductor wafer;
• detecting at least one first intensity of said incident light reflected from the semiconductor wafer at a first time;
• detecting at least one second intensity of said incident light reflected from the semiconductor wafer at a second time;
• determining a difference between the at least one first intensity and the at least one second intensity;
• and
• providing a signal when the difference between the at least one first intensity and the at least one second intensity is above a predetermined threshold, wherein the signal indicates that the transition interface has been detected.

A system of detecting a transition interface between a first dielectric material and an adjacent second dielectric material on a semiconductor wafer during a polishing process, the system comprising:

• means for initiating the polishing process, said polishing process being implemented to remove the first dielectric material and expose the second dielectric material of the semiconductor wafer;
• means for impinging an incident light of at least one predetermined wavelength on the semiconductor wafer;
• means for detecting at least one first intensity of said incident light reflected from the semiconductor wafer at a first time;
• means for detecting at least one second intensity of said incident light reflected from the semiconductor wafer at a second time;
• means for determining a difference between the at least one first intensity and the at least one second intensity;
• and
• means for providing a signal when the difference between the at least one first intensity and the at least one second intensity is above a predetermined threshold, wherein the signal indicates that the transition interface has been detected.

A polishing method for detecting a transition interface between a first dielectric material and an adjacent second dielectric material in a semiconductor wafer during a polishing process, the method comprising:

• executing the polishing process, said polishing process being executed to remove a first dielectric material and expose a second dielectric material of the semiconductor wafer;
• generating incident light of at least one predetermined wavelength upon a surface of the semiconductor wafer;
• detecting at least one reflected light intensity from the surface of the second dielectric material;
• analyzing the reflected light intensity to determine and produce a signal when the transition interface between the first dielectric and the second dielectric has been detected.