Copper contamination detection method and system for monitoring copper contamination
View Patent ↗A computer system. The computer system including a processor and memory unit coupled to the processor, the memory unit containing instructions that when executed by the processor implement a method for monitoring a solution in a tank used to fabricate integrated circuits, the method comprising the computer implemented steps of: (a) collecting data indicating of an amount of copper in a region of a substrate of a monitor, the monitor comprising an N-type region in a silicon substrate, the region abutting a top surface of the substrate, the monitor having been submerged in the solution for a preset time; (b) comparing the data to a specification for copper content of the solution; (c) if the data indicates a copper content exceeds a limit of the specification for copper, indicating a corrective action is required to prevent copper contamination of the integrated circuits; and (d) repeating steps (a) through (c) periodically.
1. A computer system comprising, a processor, a computer-readable storage device coupled to said processor, said storage device containing program code configured to be executed by said processor via said memory to implement a method for monitoring a solution in a tank of a processing tool used to fabricate integrated circuits, said method comprising:
(a) receiving data indicating of an amount of copper in a region of a substrate of a monitor, said monitor comprising an N-type region in a single-crystal silicon substrate, said region abutting a top surface of said substrate, said monitor having been submerged in said solution for a preset duration of time;
(b) converting said data indicating of said amount of copper in said region of said substrate of a monitor to data indicating an amount of copper in said solution and comparing said data indicating said amount of copper in said solution to a specification for copper content of said solution; and
(c) if said data indicating an amount of copper in said solution exceeds a limit of said specification for the copper content, indicating a corrective action is required to prevent copper contamination of said integrated circuits.
2. The computer system of claim 1 , the method further including the step of:
determining a copper concentration of said solution based on said amount of copper in said region of said substrate.
3. The computer system of claim 2 , the method further including the step of:
displaying said copper concentration of said solution on a computer screen.
4. The computer system of claim 2 , the method further including the step of:
storing said copper concentration on a computer readable storage media.
5. The computer system of claim 4 , the method further including the step of:
generating and displaying a control chart of said copper concentration over time on a computer screen.
6. The computer system of claim 1 , wherein said converting is based on an (i) empirically derived curve, (ii) a look-up table or (iii) an algorithm, said curve, table or algorithm derived from measuring amounts of copper in monitor wafers submerged, for said present duration of time, in respective aqueous solutions having known and different copper concentrations.
7. The computer system of claim 1 , wherein said data includes Total Internal Reflected X-Ray Fluorescence copper content data, Secondary Ion Mass Spectroscopy copper content data, Time of Flight SIMS copper content data, Energy Dispersive X-Ray Fluorescence copper content data, Auger Spectroscopy copper content data or X-Ray Photo-electron Spectroscopy copper content data.
8. The computer system of claim 1 , the method further including the step of:
selecting an instruction for said corrective action from a list of instructions stored on said computer system; and
displaying said instruction on a computer screen.
9. The computer system of claim 8 , wherein said instruction is selected from the group consisting of (i) an instruction to shut down said tank of said processing tool containing said solution, (ii) an instruction to limit types of product wafers allowed in said tank, (iii) an instruction to restrict fabrication levels of product wafers allowed in said tank, (iv) an instruction to limit a number of product wafers that can be processed before shutting down said tank, and (v) an instruction to shut down said tank, drain said solution from said tank, clean said tank, and refill said tank with fresh solution.
10. The computer system of claim 1 , the method further including the step of:
(d) repeating steps (a) through (c) periodically.
11. A computer system comprising, a processor, a computer-readable storage device coupled to said processor, said storage device containing program code configured to be executed by said processor via said memory to implement a method for monitoring a solution in a tank of a processing tool used to fabricate integrated circuits, said method:
(a) receiving data indicating of an amount of copper in a region of a substrate of a monitor, said monitor comprising an N-type region in a single-crystal silicon substrate, said region abutting a top surface of said substrate, said monitor having been submerged in said solution for a preset duration of time;
(b) comparing said data to a specification for copper content of said region of said substrate; and
(c) if said data indicates a copper content exceeds a limit of said specification for copper, indicating a corrective action is required to prevent copper contamination of said integrated circuits.
12. The computer system of claim 11 , the method further including the step of:
displaying said data on a computer screen.
13. The computer system of claim 11 , the method further including the step of:
storing said data on a non-transitory computer readable storage media.
14. The computer system of claim 11 , the method further including the step of:
generating and displaying a control chart of said data over time on a computer screen.
15. The computer system of claim 11 , wherein said data includes Total Internal Reflected X-Ray Fluorescence copper content data, Secondary Ion Mass Spectroscopy copper content data, Time of Flight SIMS copper content data, Energy Dispersive X-Ray Fluorescence copper content data, Auger Spectroscopy copper content data or X-Ray Photo-electron Spectroscopy copper content data.
16. The computer system of claim 11 , the method further including the step of:
selecting an instruction for said corrective action from a list of instructions stored in computer system; and
displaying said instruction on a computer screen.
17. The computer system of claim 16 , wherein said instruction is selected from the group consisting of (i) an instruction to shut down said tank of said processing tool containing said solution, (ii) an instruction to limit types of product wafers allowed in said tank, (iii) an instruction to restrict fabrication levels of product wafers allowed in said tank, (iv) an instruction to limit a number of product wafers that can be processed before shutting down said tank, and (v) an instruction to shut down said tank, drain said solution from said tank, clean said tank, and refill said tank with fresh solution.
18. The computer system of claim 11 , the method further including the step of:
(d) repeating steps (a) through (c) periodically.