Wafer stress control and topography compensation
A method of forming a semiconductor wafer includes generating a stress topography model of a semiconductor wafer with a plurality of desired structures in a desired layout. The method also includes determining a topography and calculating a compensation pattern based upon the topography, wherein the compensation pattern balances wafer topography. The method also includes patterning a semiconductor front side with the plurality of desired microstructures in the desired layout. The method also includes patterning the semiconductor back side with a compensation block mask corresponding to the compensation pattern.
1. A method of forming a semiconductor wafer, the method comprising:
providing a semiconductor wafer having a front side and a back side;
determining a local wafer topography;
calculating a backside compensation pattern based upon the local wafer topography, wherein the compensation pattern balances a wafer topography;
patterning the front side with a plurality of desired microstructures in a desired layout; and
patterning the back side with a compensation block mask corresponding to the backside compensation pattern.
2. The method of claim 1 , wherein calculating the backside compensation pattern comprises generating a predictive topography model.
3. The method of claim 1 , wherein calculating the backside compensation pattern comprises generating a calculated topography model.
4. The method of claim 1 , comprising patterning the front side with the plurality of desired microstructures before patterning the back side with the compensation block mask corresponding to the backside compensation pattern.
5. The method of claim 1 , comprising patterning the front side with the plurality of desired microstructures after patterning the back side with the compensation block mask corresponding to the backside compensation pattern.
6. The method of claim 1 , wherein the compensation block mask has a dimension of 100 to 900 micrometers.
7. The method of claim 1 , comprising covering the backside with a silicon protective layer.
8. The method of claim 1 , comprising planarizing the semiconductor wafer.
9. The method of claim 1 , wherein one of the desired microstructures has a dimension of 10 to 500 nanometers.
10. The method of claim 1 , wherein the desired microstructures impart a collective tensile stress to the wafer.
11. The method of claim 10 , wherein the backside compensation pattern imparts a tensile stress to the wafer comparable to the collective tensile stress.
12. The method of claim 1 , wherein the desired microstructures impart a collective compressive stress to the wafer.
13. The method of claim 12 , wherein the backside compensation pattern imparts a compressive stress to the semiconductor wafer comparable to the collective compressive stress.
14. The method of claim 2 , further comprising generating a block mask based upon the predictive topography model.
15. The method of claim 1 , further comprising depositing a sacrificial layer on the front side or the back side.
16. The method of claim 1 , further comprising implanting a large neutral ion by ion implantation on the backside.
17. The method of claim 16 , wherein the large neutral ion is an ion selected from the group consisting of germanium, xenon, or argon.
18. A method of forming a semiconductor wafer, the method comprising:
providing a semiconductor wafer having a front side and a back side;
forming a tensile region on the front side having a front tensile diameter; and
forming a tensile region on the back side having a back tensile diameter;
wherein the front tensile diameter varies from the back tensile diameter by a factor of at least 100.
19. The method of claim 18 , comprising covering the backside with a silicon protective layer.
20. A semiconductor wafer comprising:
a semiconductor substrate having a front side and a back side;
a back side compensation structure having a dimension of greater than or equal to 1 millimeter; and
a plurality of front side desired structures opposite the backside compensation structure, wherein each of the plurality of front side desired structures has a dimension of less than 0.5 micrometers.