Method and device for spatially periodic modification of a substrate surface
The invention relates to a method and a device for modifying in a spatially periodic manner at least in some regions a surface of a substrate ( 24 ), said surface being disposed on a sample plane (P) for which end different regions ( 211, 221, 231, 232 ) of the substrate surface are acted upon successively with a spatially periodic illumination pattern of an energy density above a processing threshold of the substrate surface, where the illumination pattern is generated by diffraction of an input beam ( 10 ) and superimposition of resulting, diffracted sub-beams ( 12, 14 ) by means of a grid interferometer ( 100 ), and where, in order to select the substrate surface region to be illuminated in each case ( 211, 221, 231, 232 ), the input beam ( 10 ) is deviated by means of a beam-deviating unit ( 16 ) arranged upstream of the grid interferometer ( 100 ).
1. Method for modifying in a spatially periodic manner at least in some regions a surface of a substrate ( 24 ), said surface being disposed on a sample plane (P) by acting upon different regions ( 211 , 221 , 231 , 232 ) of the substrate surface successively with a spatially periodic illumination pattern of an energy density above a processing threshold of the substrate surface, where the illumination pattern is generated by diffraction of an input beam ( 10 ) and superimposition of resulting, diffracted sub-beams ( 12 , 14 ) by means of a grid interferometer ( 100 ), and where, in order to select the respective substrate surface region to be illuminated ( 211 , 221 , 231 , 232 ), the input beam ( 10 ) is deviated by means of a beam-deviating unit ( 16 ) arranged upstream of the grid interferometer ( 100 ), wherein the input beam ( 10 ) passes through an F-Theta lens ( 22 ) between the beam-deviating unit ( 16 ) and the grid interferometer ( 100 ).
2. The method according to claim 1 , wherein the F-Theta lens ( 22 ) is designed as a telecentric F-Theta lens ( 22 ).
3. The method according to claim 1 , wherein the grid interferometer ( 100 ) is moved, especially rotated and/or shifted, perpendicular to its optical axis ( 20 ) by a drive in synchrony with the deviation of the input beam ( 10 ).
4. The method according to claim 3 , wherein the input beam ( 10 ) is a pulsed beam whose pulse sequence is synchronised with the deviation of the input beam ( 10 ) and the movement of the grid interferometer ( 100 ).
5. The method according to claim 3 , wherein at least one grid (G 1 ; G 2 ) of the interferometer ( 100 ) has a non-rotationally symmetrical grid structure and/or a plurality of adjacent regions (G 1 a , G 1 b ; G 2 a , G 2 b , G 2 c , G 2 d ) with different grid structures.
6. The method according to claim 1 , wherein the grid interferometer ( 100 ) comprises
a first, input-side grid (G 1 ), which exhibits grid periodicities in at least two directions, and
a second, output-side grid (G 2 ) that exhibits a plurality of pairs of sub-grids (G 2 a , G 2 b , G 2 c , G 2 d ), each pair having a grid periodicity that is identical within each pair and parallel to respectively one grid periodicity of the first grid (G 1 ), where the sub-grids of each pair (G 2 a , G 2 b , G 2 c , G 2 d ) are arranged and spaced diametrically and their respective grid periodicity is oriented parallel to their distance line,
where a variable aperture arrangement ( 52 , 54 ) for selecting from among intended, diffracted sub-beams ( 12 , 14 ) to be superimposed in the sample plane (P) is arranged downstream from the first grid (G 1 ) of the grid interferometer ( 100 ) and is varied synchronously with the deviation of the input beam ( 10 ).
7. The method according to claim 6 , wherein the input beam ( 10 ) is a pulsed beam whose pulse sequence is synchronised with the deviation of the input beam ( 10 ) and the variation of the aperture arrangement ( 52 , 54 ).
8. A device for modifying in a spatially periodic manner at least in some regions a surface of a substrate ( 24 ) to be arranged in a sample plane (P), comprising
a beam-deviating unit ( 16 ) for selecting a current processing region ( 211 , 221 , 231 , 232 ) by controlled deviation of an input beam ( 10 ) and
a grid interferometer ( 100 ) arranged downstream from the beam-deviating unit ( 16 ) which interferometer diffracts the input beam ( 10 ) and superimposes in the sample plane the resulting diffracted sub-beams ( 12 a, b ; 14 a, b ) to create a spatially periodic illumination pattern in the current processing region ( 211 , 221 , 231 , 232 ),
wherein an F-Theta lens ( 22 ) arranged between the beam-deviating unit ( 16 ) and the grid interferometer ( 100 ).
9. A device according to claim 8 , wherein the F-Theta lens ( 22 )is designed as a telecentric F-Theta lens ( 22 ).
10. A device according to claim 8 , wherein
a drive by means of which the grid interferometer ( 100 ) can be moved, especially rotated and/or shifted, perpendicularly to its optical axis ( 20 ), and
a synchronisation unit ( 36 ) by means of which the deviation of the input beam ( 10 ) and movement of the grid interferometer ( 100 ) can be controlled synchronously.
11. The device according to claim 10 , wherein the input beam ( 10 ) is a pulsed beam whose pulse sequence is synchronised by the synchronization unit ( 36 ) with the deviation of the input beam ( 10 ) and the movement of the grid interferometer.
12. The device according to claim 10 , wherein the at least one grid (G 1 ) of the grid interferometer ( 100 ) has a grid structure that is non-rotationally symmetrical and/or a plurality of adjacent regions (G 1 a , G 1 b ) with different grid structures.
13. The device according to claim 10 , wherein the sample plane (P) is provided in the form of a sample carrier ( 37 ) that is rigidly fixed to a first slide pad ( 40 ) and that the grid interferometer ( 100 ) is rigidly fixed to a second slide pad ( 44 ), where a slide surface ( 46 ) of the second slide pad ( 44 ) is arranged on a corresponding slide surface ( 42 ) of the first slide pad ( 42 ) such that the second slide pad ( 44 ) can be slid by means of the drive on the first slide pad ( 40 ) and where a pressing force sufficient to prevent relative movement of the slide pads ( 40 , 44 ) can be applied to the second slide pad ( 44 ) relative to the first slide pad ( 40 ).
14. The device according to claim 8 , wherein the grid interferometer ( 100 ) comprises
a first, input-side grid (G 1 ), which exhibits grid periodicities in at least two directions, and
a second, output-side grid (G 2 ) that exhibits a plurality of pairs of sub-grids (G 2 a , G 2 b , G 2 c , G 2 d ), each pair having a grid periodicity that is identical within each pair and parallel to respectively one grid periodicity of the first grid (G 1 ), where the sub-grids of each pair (G 2 a , G 2 b , G 2 c , G 2 d ) are arranged and spaced diametrically and their respective grid periodicity is oriented parallel to their distance line
where a variable aperture arrangement is placed downstream from the first grid of the grid interferometer which arrangement can be used to select diffracted sub-beams intended to be superimposed in the sample plane and where a second synchronization unit ( 36 ) is provided by means of which the deviation of the input beam ( 10 ) and the variation of the aperture arrangement ( 52 , 54 ) can be controlled synchronously to select the sub-beams ( 12 , 14 ).
15. The device according to claim 14 , wherein the input beam ( 10 ) is a pulsed beam whose pulse sequence is synchronised by means of the synchronization unit ( 36 ) with the deviation of the input beam ( 10 ) and the variation of the aperture arrangement ( 52 , 54 ).