Patent Number: 
Section: claims

1. A dynamic pattern generator for reflection electron beam lithography comprising:conductive pixel pads;an insulative border surrounding each conductive pixel pad so as to electrically isolate the conductive pixel pads from each other; andconductive elements coupled to the conductive pixel pads for controllably applying voltages to the conductive pixel pads,wherein the conductive pixel pads are cup shaped with a bottom portion, a sidewall portion, and an open cavity. 2. The dynamic pattern generator of claim 1, wherein the cup-shaped pixel pads provide high contrast between reflective and absorptive pixels by reducing backscattering of low energy electrons. 3. The dynamic pattern generator of claim 1, wherein a height of the sidewall portion is greater than a width of the bottom portion. 4. A pattern generating apparatus comprising:conductive pixel pads;conductive elements coupled to the conductive pixel pads for controllably applying voltages to the conductive pixel pads;an insulative border surrounding each conductive pixel pad so as to electrically isolate the conductive pixel pads from each other; anda well structure with sidewalls and a cavity configured above each conductive pixel pad. 5. The apparatus of claim 4, wherein the sidewalls comprise alternating layers of conductive and insulative materials. 6. The apparatus of claim 5, wherein the sidewalls comprise at least three layers of insulative material alternating with at least three layers of conductive material. 7. The apparatus of claim 6, wherein voltages are applied to three layers of conductive material in the sidewalls. 8. The apparatus of claim 7, wherein a first voltage applied to an upper conductive layer away from the pixel pad is a small positive voltage, a second voltage applied to a middle conductive layer in a middle region of the sidewalls is a large positive voltage, a third voltage applied to a lower conductive layer close to the pixel pad is a negative voltage. 9. The apparatus of claim 8, wherein a zero voltage is applied to a pixel pad to be in an absorptive state, and a positive voltage between the first and second voltages is applied to a pixel pad to be in a reflective state. 10. The apparatus of claim 6, wherein a voltage applied to at least one of the conductive layers is adjusted to change a numerical aperture of a reflected beam of electrons when a pixel pad is in a reflective state. 11. The apparatus of claim 4, wherein a height of the sidewalls is greater than a width of the conductive pixel pads. 12. A method of reflective electron beam lithography, the method comprising:forming an incident electron beam;directing the incident electron beam to a dynamically patterned structure having conductive pixel pads with a sidewall surrounding each pixel pad;reflecting electrons from a first set of pixel pads of the dynamically patterned structure having a lower voltage level applied thereto;absorbing electrons from a second set of pixel pads of the dynamically patterned structure having a higher voltage level applied thereto; anddirecting the reflected electrons towards a target substrate to imprint a lithographic pattern. 13. The method of claim 12, wherein the lithographic pattern of reflected electrons comprises an on/off pattern. 14. The method of claim 12, wherein the lithographic pattern of reflected electrons comprises a gray scale pattern. 15. The method of claim 12, wherein each pixel pad and surrounding sidewall comprises a cup-shaped conductive structure. 16. The method of claim 12, wherein the surrounding sidewall comprises alternating layers of insulative and conductive material, and wherein voltages are applied to the layers of conductive material.