Dopant marker for precise recess control

1. A method comprising:

depositing a layer of material on a substrate;

during deposition of the material, at a predetermined depth, implanting a first dopant and a second dopant in the material at different lateral locations, the second dopant being different from the first dopant;

etching the material;

during the etching, detecting the positions and intensities of the first and second dopants; and

calculating lateral homogeneity of the material in situ from the intensities of the first and second dopants.

2. The method according to claim 1 , wherein the first and second dopants do not change the electrical properties of the material.

3. The method according to claim 2 , wherein the detecting the positions and intensities of the first and second dopants is by detecting and analyzing a physical property of the first and second dopants.

4. The method according to claim 2 , wherein the detecting the positions and intensities of the first and second dopants is by detecting and analyzing a spectral property of the first and second dopants.

5. The method according to claim 2 , wherein the detecting the positions and intensities of the first and second dopants is by detecting and analyzing a chemical property of the first and second dopants.

6. The method according to claim 1 , wherein the implanting the first and second dopants is by beam implantation.

7. The method according to claim 1 , wherein the layer of material has a thickness of 100 nm to 2 μm.

8. The method according to claim 7 , wherein the first and second dopants are implanted at a depth of ¼ to ¼ of the thickness of the layer of material.

9. The method according to claim 1 , wherein the first and second dopants are implanted as concentric rings.

10. The method according to claim 9 , further comprising:

implanting a third dopant in the material as a third concentric ring;

during the etching, detecting the position and intensity of the third dopant; and

verifying the calculated lateral homogeneity of the material from the position and intensity of the third dopant.

11. A method comprising:

depositing an interlayer dielectric (ILD) on a substrate;

during deposition of the ILD, at a predetermined depth, implanting a first dopant and a second dopant in the ILD at different lateral locations, the second dopant being different from the first dopant;

etching the ILD;

during the etching, detecting the positions and intensities of the first and second dopants; and

calculating lateral homogeneity of the ILD in situ from the intensities of the first and second dopants.

12. The method according to claim 11 , wherein the ILD comprises tetraethyl orthosilicate (TEOS).

13. The method according to claim 12 , wherein the first and second dopants are each boron (B), nitrogen (N), or phosphorus (P).

14. The method according to claim 11 , wherein the detecting the positions and intensities of the first and second dopants is by detecting and analyzing a physical, spectral, or chemical property of the first and second dopants.

15. The method according to claim 11 , wherein the implanting the first and second dopants is by beam implantation.

16. The method according to claim 11 , wherein the ILD has a thickness of 100 nm to 2 μm.

17. The method according to claim 16 , wherein the first and second dopants are implanted at a depth of ¼ to ¼ of the thickness of the ILD.

18. The method according to claim 11 , wherein the first and second dopants are implanted simultaneously as concentric rings.

19. The method according to claim 18 , further comprising:

implanting a third dopant, different from the first and second dopants, in the ILD, simultaneously with the first and second dopants as a third concentric ring;

during the etching, detecting the position and intensity of the third dopant; and

verifying the calculated lateral homogeneity of the ILD from the position and intensity of the third dopant.

20. A method comprising:

depositing a tetraethyl orthosilicate (TEOS) interlayer dielectric (ILD) on a substrate;

during deposition of the TEOS ILD, at a predetermined depth, ion implanting first, second, and third dopants of boron (B), nitrogen (N), and/or phosphorus (P), in the TEOS as concentric circles, the first, second, and third dopants all being different from each other;

etching the TEOS ILD;

during the etching,

detecting and analyzing a physical, spectral, or chemical property of each of the first, second, and third dopants to determine the intensity and position of the each of the first, second, and third dopants; and

calculating removal rates and lateral homogeneity of the TEOS ILD in situ from the intensities and positions of the first, second, and third dopants.