Method for producing a multi-beam deflector array device having electrodes
View Patent ↗The disclosure relates to a method for producing a multi-beam deflector array device with a plurality of openings for use in a particle-beam exposure apparatus, in particular a projection lithography system, said method starting from a CMOS wafer and comprising the steps of generating at least one pair of parallel trenches on the first side of the wafer blank at the edges of an area where the circuitry layer below is non-functional, the trenches reaching into the layer of bulk material; passivating the sidewalls and bottom of the trenches; depositing a conducting filling material into the trenches, thus creating columns of filling material serving as electrodes; attaching metallic contact means to the top of the electrodes; structuring of an opening between the electrodes, said opening stretching across abovementioned area so that the columns are arranged opposite of each other on the sidewalls of the opening.
1. A method for producing a multi-beam deflector array device with a plurality of openings for use in a particle-beam exposure apparatus, in particular a projection lithography system, starting from a CMOS wafer, comprising a silicon wafer having, on a first side, a circuitry layer beneath a contact layer and a cover layer, the cover layer serving as a passivation layer, said method comprising the following steps, performed at at least one location on the wafer:
a) Generating at least one pair of parallel trenches on the first side of the wafer blank at the edges of an area where the circuitry layer below is non-functional, the trenches reaching through the passivation layer and the circuitry layer into the layer of bulk material, the trenches being located at a predetermined distance from each other according to the dimensions of said area,
b) passivating the sidewalls and bottom surfaces of the trenches,
c) depositing a conducting filling material into the trenches, thus creating columns of filling material designed to serve as electrodes,
d) attaching metallic contact means to the electrodes where they reach out of the trenches on the first side of the CMOS wafer,
e) structuring of an opening located between the electrodes, said opening extending over the area mentioned in step a) so that the electrodes are arranged opposite of each other on the sidewalls of the opening.
2. The method of claim 1 , wherein in step a) two pairs of parallel trenches are generated on the first side of the wafer blank, the direction of the trenches of the first pair being orthogonal to the direction of the trenches of the second pair, wherein the trenches of the second pair are connected to one trench of the first pair, forming a U-shaped trench in the first side of the wafer blank.
3. The method of claim 1 , wherein in step a) the trenches are structured by using the method of DRIE.
4. The method of claim 1 , wherein the filling material in step b) is Tungsten (W) or Silicon-Germanium (SiGe).
5. The method of claim 1 , wherein in step c) the columns are contacted with Titanium Nitride (TiN).
6. The method of claim 1 , wherein in step d) the etching of the apertures is done by using the method of DRIE.
7. The method of claim 1 , wherein step e) includes the substep of abrasion of a second side opposite to the first side of the wafer blank, thus reducing the thickness of the wafer blank until the opening so that the opening reaches through the whole wafer blank.
8. The method of claim 7 , wherein before the abrasion the bottom part of the openings is enlarged preferably using isotropic etching, thus creating a spherical cavity in the bulk material, which is then opened.
9. The method of claim 1 , wherein in a step f) a cover plate is provided on the first side of the multi-beam deflector array device, the cover plate comprising a silicon membrane and having a plurality of apertures, each aperture being associated with a subsequent opening in the multi-beam deflector array device.
10. The method of claim 9 , wherein the cover plate of step f) is produced separately from the multi-beam deflector array device and fixed to the multi-beam deflector array device by bonding or clamping.
11. A multi-beam deflector array device produced with the method of claim 1 .
12. A multi-beam deflector array device produced with the method of claim 2 .
13. A multi-beam deflector array device produced with the method of claim 3 .
14. A multi-beam deflector array device produced with the method of claim 4 .
15. A multi-beam deflector array device produced with the method of claim 5 .
16. A multi-beam deflector array device produced with the method of claim 6 .
17. A multi-beam deflector array device produced with the method of claim 7 .
18. A multi-beam deflector array device produced with the method of claim 8 .
19. A multi-beam deflector array device produced with the method of claim 9 .
20. A multi-beam deflector array device produced with the method of claim 10 .