Hotspot avoidance method of manufacturing integrated circuits
A method includes cropping a plurality of images from a layout of an integrated circuit, generating a first plurality of hash values, each from one of the plurality of images, loading a second plurality of hash values stored in a hotspot library, and comparing each of the first plurality of hash values with each of the second plurality of hash values. The step of comparing includes calculating a similarity value between the each of the first plurality of hash values and the each of the second plurality of hash values. The method further includes comparing the similarity value with a pre-determined threshold similarity value, and in response to a result that the similarity value is greater than the pre-determined threshold similarity value, recording a position of a corresponding image that has the result. The position is the position of the corresponding image in the layout.
1. A method comprising:
determining likely hotspots of a wafer;
comparing hash values of the likely hotspots with stored hash values in a hotspot library to determine a similarity value for each of the likely hotspots; and
based on the similarity values determined in the comparing, selecting a polishing recipe from the hotspot library.
2. The method of claim 1 further comprising polishing the wafer using the polishing recipe.
3. The method of claim 1 , wherein the polishing recipe is selected as corresponding to a highest-ranking hotspot in the likely hotspots, and wherein the highest-ranking hotspot has a highest similarity value among the similarity values.
4. The method of claim 1 , wherein the polishing recipe is selected as corresponding to a non-highest-ranking hotspot in the likely hotspots, and wherein the non-highest-ranking hotspot has a lower similarity value than a highest similarity value among the similarity values.
5. The method of claim 1 , wherein the determining the likely hotspots comprises:
cropping a plurality of images from a layout of the wafer;
generating a first plurality of hash values, each from one of the plurality of images;
loading a second plurality of hash values stored in the hotspot library;
comparing each of the first plurality of hash values with each of the second plurality of hash values, wherein the comparing comprises calculating an additional similarity value between the each of the first plurality of hash values and the each of the second plurality of hash values; and
comparing the additional similarity value with a pre-determined threshold similarity value, wherein the additional similarity value higher than the pre-determined threshold similarity value correspond to a hotspot.
6. The method of claim 1 , wherein the polishing recipe comprises a slurry flow value for polishing the wafer.
7. The method of claim 1 , wherein the polishing recipe comprises a down force value for pressing the wafer against a corresponding polishing pad.
8. The method of claim 1 , wherein the polishing recipe comprises an on/off state of a pad conditioner that is used when the wafer is polished.
9. The method of claim 1 , wherein the likely hotspots comprise out-of-specification recesses.
10. The method of claim 1 , wherein the likely hotspots comprise out-of-specification humps.
11. A method comprising:
providing a list of candidate hotspots of a wafer;
finding hotspots from a hotspot library, wherein the found hotspots correspond to some of the list of candidate hotspots;
finding polishing recipes corresponding to the hotspots found from the hotspot library;
selecting a polishing recipe from the found polishing recipes; and
polishing the wafer using the polishing recipe.
12. The method of claim 11 , wherein the list of candidate hotspots comprise out-of-specification recesses that are likely to occur when the wafer is polished.
13. The method of claim 11 , wherein the list of candidate hotspots comprise out-of-specification humps that are likely to occur when the wafer is polished.
14. The method of claim 11 , wherein the finding the hotspots from the hotspot library comprises finding stored hotspots in the hotspot library that have similar hash values to the list of candidate hotspots.
15. The method of claim 14 , wherein the stored hotspots in the hotspot library are found by comparing first hash values of the list of candidate hotspots with hash values stored in the hotspot library.
16. The method of claim 11 further comprising ranking the list of candidate hotspots based on their similarity values to the stored hotspots.
17. The method of claim 16 , wherein the selected polishing recipe has a highest similarity value among all of similarity values of the list of candidate hotspots.
18. A method comprising:
providing a likely hotspots of a wafer;
finding hotspots from a hotspot library, wherein the found hotspots correspond to the likely hotspots;
finding polishing recipes correspond to the hotspots found from the hotspot library;
ranking the likely hotspots;
selecting a polishing recipe from the polishing recipes, wherein the selected polishing recipe has a highest rank that is determined by the ranking; and
polishing the wafer using the selected polishing recipe.
19. The method of claim 18 , wherein the ranking is based on similarity values of hash values of the likely hotspots to stored hash values in the hotspot library.
20. The method of claim 18 further comprising:
after the wafer is polished, inspecting the wafer to determine status of the likely hotspots; and
modifying the polishing recipe.