Patent Number: 
Section: claims

1. A method of controlling a beam used to generate a pattern on a target surface, comprising:generating a beam of charged particles and directing said beam to a mask surface; andcausing said beam to be one of absorbed by and reflected from said mask surface, thereby either precluding or allowing said beam to strike said target surface based on a reflection characteristic of said mask surface,wherein said reflection characteristic is due to a mechanism such that a pattern on said mask surface is changeable without having to re-fabricate said mask,wherein said mechanism is due to providing a difference of electrical potential on said mask surface and said difference of electrical potential is changeable without further modifying said mask, thereby providing a programmable mask by selectively controlling an electrical potential on different portions of said mask surface to change a pattern thereon,wherein said programmable mask comprises a matrix of programmable portions on said mask surface, andwherein said matrix of programmable portions comprises a matrix of photodiodes. 2. The method of claim 1, wherein said charged particles comprise electrons. 3. An apparatus for generating a pattern on a target wafer surface, comprising:a beam generator for generating a beam of charged particles in a first path;a magnetic deflector for deflecting said beam from said first path onto a mask surface, wherein a characteristic of said mask surface causes charged particles of said deflected beam to be one of absorbed by and reflected from said mask surface; anda magnetic deflector to deflect said charged particles that are reflected from said mask surface to strike said target surface,wherein said reflection characteristic is due to a difference in potential on said mask surface in a pattern that can be changed without re-fabricating said mask,wherein said pattern is due to a difference of electrical potential on different areas of said mask surface and said difference of electrical potential is selectively changeable, thereby providing a programmable mask,wherein said programmable mask comprises a matrix of programmable portions on said mask surface,wherein said matrix of programmable portions comprises a matrix of photodiodes. 4. The apparatus of claim 3, wherein said deflection is approximately 90° and said first magnetic deflector and said second magnetic deflector are the same. 5. A mask used for controlling a beam for generating a pattern on a target wafer surface, said beam comprising charged particles directed onto a surface of said mask, said mask comprising:a substantially planar surface, wherein said surface contains a plurality of areas, each said area having a surface characteristic such that said beam is one of substantially absorbed by said surface and reflected from said surface, and a pattern created by said plurality of areas on said mask surface can be changed without having to re-fabricate said mask,wherein said pattern is due to a difference of electrical potential on different areas of said mask surface and said difference of electrical potential is selectively changeable, thereby providing a programmable mask,wherein said programmable mask comprises a matrix of programmable portions on said mask surface,wherein said matrix of programmable portions comprises a matrix of photodiodes. 6. The method of claim 1, further comprising:controlling where a light shines, said light thereby selectively causing ones of said photodiodes of said matrix of photodiodes to generate an electrical potential. 7. The method of claim 6, further comprising:retrieving data from a signal-bearing medium tangibly embodying a machine-readable data retrievable and executable by a digital processing apparatus, said data being retrieved for controlling said reflection of said beam particles. 8. A method of controlling a beam used to generate a pattern on a target surface, comprising:generating a beam of charged particles and directing said beam to a mask surface; andcausing said beam to be one of absorbed by and reflected from said mask surface, thereby either precluding or allowing said beam to strike said target surface based on a reflection characteristic of said mask surface,wherein said reflection characteristic is due to a mechanism such that a pattern on said mask surface is changeable without having to re-fabricate said mask,wherein said mechanism is due to a difference in electrical potential on said mask surface caused by a photovoltage material having a light selectively shining thereon, thereby allowing said pattern to be readily changed.