Customized polish pads for chemical mechanical planarization
View Patent ↗A polishing pad for chemical mechanical planarization of a film on a substrate is customized by obtaining one or more characteristics of a structure on a substrate. For example, when the structure is a chip formed on a semiconductor wafer, the one or more characteristics of the structure can include chip size, pattern density, chip architecture, film material, film topography, and the like. Based on the one or more characteristics of the structure, a value for the one or more chemical or physical properties of the pad is selected. For example, the one or more chemical or physical properties of the pad can include pad material hardness, thickness, surface grooving, pore size, porosity, Youngs modulus, compressibility, asperity, and the like.
1. A method of making a polishing pad for chemical mechanical planarization of a substrate, the method comprising:
obtaining one or more characteristics of a structure on the substrate;
selecting a value for one or more chemical or physical properties for the pad to be used in chemical mechanical planarization of the substrate based on the obtained one or more characteristics of the structure on the substrate; and
making the pad having the value for the one or more chemical or physical properties by adjusting the chemical formulation of the pad.
2. The method of claim 1 , wherein the one or more characteristics of the structure includes a size of the structure.
3. The method of claim 1 , wherein the one or more characteristics of the structure includes a pattern density of the structure.
4. The method of claim 1 , wherein the one or more characteristics of the structure includes film material and a number of different materials.
5. The method of claim 1 , wherein the one or more chemical or physical properties for the pad include hardness, porosity, Young's modulus or compressibility of the pad.
6. The method of claim 1 , wherein selecting the value for the one or more chemical or physical properties for the pad comprises:
performing a simulation of planarization of the substrate with a model of a CMP process using the pad with a range of values for the one or more chemical or physical properties for the pad; and
selecting the value for the one or more chemical or physical properties based on the simulation.
7. The method of claim 6 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
providing a pattern density and a deposition bias as inputs to the model of the CMP process.
8. The method of claim 6 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
obtaining a planarization length from the model of the CMP process; and
performing a sensitivity analysis to determine a correlation between planarization length and the one or more chemical or physical properties of the pad.
9. The method of claim 8 , wherein the value for the one or more chemical or physical properties is selected based on the determined correlation between planarization length and the one or more chemical or physical properties of the pad to optimize planarization length.
10. The method of claim 6 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
identifying dishing and/or erosion from the model of the CMP process; and
performing a sensitivity analysis to determine a correlation between the one or more chemical or physical properties of the pad and dishing and/or erosion.
11. The method of claim 10 , wherein the value for the one or more chemical or physical properties is selected based on the determined correlation between the one or more chemical or physical properties of the pad and dishing and/or erosion to reduce dishing and/or erosion.
12. The method of claim 6 , wherein one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
identifying over-polishing and/or under-polishing from the model of the CMP process; and
performing a sensitivity analysis to determine a correlation between the one or more chemical or physical properties of the pad and over-polishing and/or under-polishing.
13. The method of claim 12 , wherein the value for the one or more chemical or physical properties is selected based on the determined correlation between the one or more chemical or physical properties of the pad and over-polishing and/or under-polishing to reduce over-polishing and/or under-polishing.
14. The method of claim 1 , wherein the structure is an optoelectronic device.
15. The method of claim 1 , wherein the substrate is a magnetic disk, an optical disk, a ceramic substrate, or a nano-composite substrate.
16. The method of claim 1 , wherein the substrate is a semiconductor wafer and the structure is a chip, and wherein selecting the value for one or more chemical or physical properties for the pad comprises:
performing a simulation of a chemical mechanical planarization of the wafer with a model of a CMP process using the obtained one or more characteristics of the chip and a range of values for the one or more chemical or physical properties of the pad; and
selecting the value for one or more chemical or physical properties for the pad based on the simulation.
17. The method of claim 16 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and wherein the one or more characteristics of the chip includes a pattern density of the chip.
18. The method of claim 16 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
obtaining a planarization length from the model of the CMP process; and
performing a sensitivity analysis to determine a correlation between planarization length and the one or more chemical or physical properties of the pad.
19. The method of claim 18 , wherein the value for the one or more chemical or physical properties is selected based on the determined correlation between planarization length and the one or more chemical or physical properties of the pad to optimize planarization length.
20. The method of claim 16 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
identifying dishing and/or erosion from the model of the CMP process; and
performing a sensitivity analysis to determine a correlation between the one or more chemical or physical properties of the pad and dishing and/or erosion.
21. The method of claim 20 , wherein the value for the one or more chemical or physical properties is selected based on the determined correlation between the one or more chemical or physical properties of the pad and dishing and/or erosion to reduce dishing and/or erosion.
22. The method of claim 16 , wherein the one or more chemical or physical properties of the pad include hardness, porosity, Young's modulus, or compressibility of the pad, and further comprising:
identifying over-polishing and/or under-polishing from the model of the CMP process; and
performing a sensitivity analysis to determine a correlation between the one or more chemical or physical properties of the pad and over-polishing and/or under-polishing.
23. The method of claim 22 , wherein the value for the one or more chemical or physical properties is selected based on the determined correlation between the one or more chemical or physical properties of the pad and over-polishing and/or under-polishing to reduce over-polishing and/or under-polishing.
24. The method of claim 1 , the method further comprising:
compensating for pattern density effects for different chip architectures; and
optimizing a derived planarization length, response characteristics for dishing and/or erosion, or final step height at specific pattern features to attain local and global planarization.
25. The method of claim 24 , wherein the optimization is performed during planarization of a silicon integrated circuit.
26. The method of claim 24 , wherein the optimization is performed during planarization of an optoelectronic device.
27. The method of claim 24 , wherein the optimization is performed during planarization of a magnetic or optical disk.
28. The method of claim 24 , wherein the optimization is performed during planarization of film on a ceramic or nano-composite substrate.
29. The method of claim 1 , wherein the substrate is a semiconductor wafer and the structure is a chip.