Method for thermally treating substrates

1. A method of thermally treating substrates, including the steps of:

heating a substrate via a plurality of separately controllable heating elements, each of which has a prescribed desired-value profile;

during a thermal treatment, locally measuring the temperature of a surface of the substrate facing away from the heating elements;

determining temperature inhomogeneities occurring on said substrate surface;

defining new desired-value profiles based on said determined temperature inhomogeneities; and

providing said new desired-value profiles for subsequent treatment processes.

2. A method according to claim 1 , wherein a temperature inhomogeneity occurring during a thermal treatment is taken into account in an anticipatory manner, in terms of time, during said definition of said desired-value profiles.

3. A method according to claim 1 , wherein the temperature of said substrate surface is determined at prescribed surface points.

4. A method according to claim 3 , wherein an average value of all measured temperature values from a surface region associated with a surface point is assigned to said surface points.

5. A method according to claim 4 , wherein said association of said surface regions to said surface points remains constant during at least one measurement cycle.

6. A method according to claim 3 , wherein said definition of a new desired-value profile is effected with the aid of a weighted association of individual ones of said surface points to said heating elements.

7. A method according to claim 6 , wherein said weighted association remains constant during at least one measurement cycle.

8. A method according to claim 6 , wherein said weighted association is varied during said definition of a new desired-value profile.

9. A method according to claim 1 , wherein time intervals for desired-value changes are newly selected during the definition of new desired-value profiles.

10. A method according to claim 1 , wherein a new definition of a desired-value profile is effected only if temperature inhomogeneities occur above a prescribed threshold value.

11. A method according to claim 1 , wherein during a thermal treatment, said substrate is disposed on a plate arranged between said heating elements and said substrate.

12. A method according to claim 1 , wherein as original desired-value profiles normalized desired-value profiles are used that are calculated from an optimized desired-value profile.

13. A method of optimizing desired-value profiles of a plurality of separately controllable heating elements for the thermal treatment of substrates, said method including the steps of:

heating said heating elements with the aid of respectively prescribed desired-value profiles;

during said heating step, locally measuring the temperature of a surface of a substrate facing away from said heating elements;

determining, as a function of time, temperature inhomogeneities occurring on said substrate surface;

defining new desired-value profiles based on said temperature inhomogeneities occurring during a treatment process;

using said new desired-value profiles for a subsequent heating process; and

repeating the aforementioned steps until, at every point in time of said heating, said temperature inhomogeneities are below a predetermined threshold value.

14. A method according to claim 13 , wherein optimization is carried out for different substrates and different end temperatures of a thermal treatment.

15. A method according to claim 13 , wherein originally prescribed desired-value profiles are normalized desired-value profiles calculated based on previously optimized desired-value profiles.