Fabrication of three dimensional structures
View Patent ↗The present disclosure relates to a method for generating a three-dimensional microstructure in an object. In one embodiment, a method for fabricating a microscopic three-dimensional structure is provided. A work piece is provided that includes a target area at which the three-dimensional structure is to be fabricated. The target area has a plurality of virtual dwell points. A shaped beam is provided to project onto the work piece. The intersection of the shaped beam with the work piece defines a beam incidence region that has a desired shape. The beam incidence region is sufficiently large to encompass multiple ones of the virtual dwell points. The shaped beam is moved across the work piece such that different ones of the virtual dwell points come into it and leave it as the beam moves across the work piece thereby providing different doses to different ones of the virtual dwell points as the different dwell points remain in the beam incidence region for different lengths of time during the beam scan. In this way, a desired dose array of beam particles is applied onto the target area to form the three dimensional microstructure.
1. A method for fabricating a microscopic three-dimensional structure, comprising:
providing a work piece having a target scan area;
forming a shaped beam using a shaping aperture and at least one focusing lens;
focusing the shaved beam on the work piece, the intersection of the shaped beam and the work piece forming a boundary incidence region with a desired shape, said shaped beam having a substantially uniform beam intensity throughout the boundary incidence region; and
scanning the shaped beam across the surface of the workpiece the workpiece by using deflectors that are positioned between the shaping aperture and the work piece and scanning said beam within the target scan area according to a predefined path resulting in a desired dose array being applied to the target scan area whereby a three dimensional structure corresponding to the dose array is formed on the target scan area.
2. The method of claim 1 in which scanning the shaped beam across the surface of the workpiece within the target scan area according to a predefined path further comprises
defining a plurality of virtual dwell points within the target scan area; and
scanning the shaped beam across the work piece, different ones of the virtual dwell points coming into the moving beam incidence region and leaving the beam incidence region as the beam moves across die work piece, the beam providing different doses to different ones of the virtual dwell points as the different dwell points remain in the beam incidence region for different lengths of time during the beam scan.
3. The method of claim 1 in which forming a shaped beam includes forming a shaped charged particle beam.
4. The method of claim 1 in which scanning the shaped beam across the surface of the workpiece further comprises removing material from the workpiece surface by milling.
5. The method of claim 1 in which scanning the shaped beam across the surface of the workpiece further comprises beam-induced deposition of a material onto the work piece.
6. The method of claim 1 in which focusing the shaped beam on the work piece comprises using at least one focusing lens located between the shaping aperture and the workpiece to focus an image of the aperture on the surface of the workpiece.
7. The method of claim 6 in which the at least one focusing lens comprises at least one electrostatic or magnetic lens.