Variable-spot scanning in an electron beam exposure system

Claim 2

Apparatus for fabricating microminiature devices by selectively irradiating a radiation-sensitive layer (10) with a variable-spot-size radiant beam to define a pattern in said layer, said apparatus comprising first and second mask plates (26, 40) spaced apart from each other along a main longitudinal axis (22) or said apparatus and each having an aperture configuration therethrough, means (18) for directing a radiant beam at said first mask plate (26) to illuminate its aperture configuration (28) in its entirety, means (48) for selectively deflecting the image of the beam transmitted through the aperture configuration (28) in said first mask plate (26) to control the alignment of said image with respect to the aperture configuration (42) in said second mask plate (40) thereby to vary the cross-sectional area of the beam transmitted through said second mask plate, characterized in that said apparatus further comprises a third mask plate (56) spaced apart from said second mask plate (40) along said axis (22), means interposed between said second and third mask plates for focusing onto said third mask plate the image of the beam that appears in the plane of said second mask plate and that is transmitted through said second mask plate to form an image on said third mask plate of the cross-sectional area of the beam transmitted through said second mask plate, and means (54) for selectively deflecting the image of the beam transmitted through the aperture configuration (42) in said second mask plate (40) to control the alignment of said image with respect to the aperture configuration (60) in said third mask plate (56) thereby to vary the cross-sectional area of the beam transmitted through said third mask plate toward said radiation-sensitive layer (10).

Claim 3

Apparatus as in claim 1 further including means (64, 66, 68) for demagnifying the image that is transmitted through the aperture configuration (60) in said third mask plate (56) and for focusing said image onto said radiation-sensitive layer (10).

Claim 4

Apparatus for fabricating microminiature devices by selectively irradiating a radiation-sensitive layer (10) with a variable-spot-size radiant beam to define a pattern in said layer, said apparatus comprising first and second mask plates (26, 40) spaced apart from each other along a main longitudinal axis (22) of said apparatus and each having an aperture configuration therethrough, means (18) for directing a radiant beam at said first mask plate (26) to illuminate its aperture configuration (28) in its entirety, means (48) for selectively deflecting the image of the beam transmitted through the aperture configuration (28) in said first mask plate (26) to control the alignment of said image with respect to the aperture configuration (42) in said second mask plate (40) thereby to vary the cross-sectional area of the beam transmitted through said second mask plate. characterized in that said apparatus further comprises a third mask plate (56) spaced apart from said second mask plate (40) along said axis (22), means (54) for selectively deflecting the image of the beam transmitted through the aperture configuration (42) in said second mask plate (40) to control the alignment of said image with respect to the aperture configuration (60) in said third mask plate (56) thereby to vary the cross-sectional area of the beam transmitted through said third mask plate toward said radiation-sensitive layer (10), means (64, 66, 68) for demagnifying the image that is transmitted through the aperture configuration (60) in said third mask plate (56) and for focusing said image onto said radiation-sensitive layer (10), and means (14) connected to said first and second mentioned deflecting means (48, 54) for applying sets or signals thereto to deflect and images along orthogonally disposed axes that are perpendicular to said main axis (22) thereby to establish for each set of signals a specified variable-spot-size image emanating from the aperture configuration (60) in said third plate (56).

Claim 5

Apparatus for fabricating microminiature devices by selectively irradiating a radiation-sensitive layer (10) with a variable-spot-size radiant beam to define a pattern in said layer, said apparatus comprising first and second mask plates (26, 40) spaced apart from each other along a main longitudinal axis (22) of said apparatus and each having an aperture configuration therethrough, means (18) for directing a radiant beam at said first mask plate (26) to illuminate its aperture configuration (28) in its entirety, means (48) for selectively deflecting the image of the beam transmitted through the aperture configuration (28) in said first mask plate (26) to control the alignment of said image with respect to the aperture configuration (42) in said second mask plate (40) thereby to vary the cross-sectional area of the beam transmitted through said second mask plate. characterized in that said apparatus further comprises a third mask plate (56) spaced apart from said second mask plate (40) along said axis (22), means (54) for selectively deflecting the image of the beam transmitted through the aperture configuration (42) in said second mask plate (40) to control the alignment of said image with respect to the aperture configuration (60) in said third mask plate (56) thereby to vary the cross-sectional area of the beam transmitted through said third mask plate toward said radiation-sensitive layer (10), means (64, 66, 68) for demagnifying the image that is transmitted through the aperture configuration (60) in said third mask plate (56) and for focusing said image onto said radiation-sensitive layer (10), and means (14) connected to said first and second mentioned deflecting means (48, 54) for applying sets or signals thereto to deflect and images along orthogonally disposed axes that are perpendicular to said main axis (22) thereby to establish for each set of signals a specified variable-spot-size image emanating from the aperture configuration (60) in said third plate (56).

Claim 6

Apparatus as in claim 3 further including means (78 through 81) for scanning said beam in a raster-scan fashion over said radiation-sensitive layer (10) along plural scan lines each of which has a multiplicity of address locations therealong.

Claim 7

Apparatus as in claim 4 wherein the aperture configurations (28, 42, 60) in said first, second and third mask plates (26, 40, 56) are respectively different.

Claim 8

Apparatus as in claim 3 further including means (82) for scanning said beam in a vector-scan fashion over said radiation-sensitive layer.

Claim 9

Apparatus as in claim 6 wherein the aperture configurations (28, 42) in said first and second mask plates (26, 40) are the same and the aperture configuration (60) in said third mask plate (56) is different therefrom.

Claim 10

Apparatus for scanning a variable-spot-size radiant beam over a work surface to irradiate selected portions of the surface in connection with the fabrication of a microminiature device, said apparatus comprising first, second and third mask plates spaced apart from each other along a main longitudinal axis of said apparatus and each having an aperture configuration therethrough, means for directing a radiant beam at said first mask plate to illuminate in its entirety the aperture configuration therethrough, means interposed between said first and second mask plates and between said second and third mask plates for focusing onto said second mask plate the image of the beam that appears in the plane of said first mask plate and that is transmitted through said first mask plate and for focusing onto said third mask plate the image of the beam that appears in the plane of said second mask plate and that is transmitted through said second mask plate, and means interposed between said first and second mask plates and between said second and third mask plates for deflecting the image of the beam transmitted through the aperture configuration in said first plate with respect to the aperture configuration in said second plate and for deflecting the image of the beam transmitted through the aperture configuration in said second plate with respect to the aperture configuration in said third plate to illuminate any specified portion or the aperture configuration in said third plate thereby to define a variable-spot-size beam for propagation toward said work surface.

Claim 11

Apparatus for scanning a variable-spot-size radiant beam over a work surface to irradiate selected portions of the surface in connection with the fabrication of a microminiature device, said apparatus comprising first, second and third mask plates spaced apart from each other along a main longitudinal axis of said apparatus and each having an aperture configuration therethrough, means for directing a radiant beam at said first mask plate to illuminate in its entirety the aperture configuration therethrough, means interposed between said first and second mask plates and between said second and third mask plates for focusing onto said second mask plate the image of the beam that appears in the plane of said first mask plate and that is transmitted through said first mask plate and for focusing onto said third mask plate the image of the beam that appears in the plane of said second mask plate and that is transmitted through said second mask plate, and means interposed between said first and second mask plates and between said second and third mask plates for deflecting the image of the beam transmitted through the aperture configuration in said first plate with respect to the aperture configuration in said second plate and for deflecting the image of the beam transmitted through the aperture configuration in said second plate with respect to the aperture configuration in said third plate to illuminate any specified portion or the aperture configuration in said third plate thereby to define a variable-spot-size beam for propagation toward said work surface.

Claim 12

Apparatus as in claim 8 further including means for demagnifying the image transmitted through the aperture configuration in said third plate and for focusing said image onto said work surface, and means for scanning said demagnified and focused image over said work surface to selectively irradiate portions thereof.

Claim 13

Apparatus for scanning a variable-spot-size radiant beam over a work surface to irradiate selected portions of the surface in connection with the fabrication of a microminiature device, said apparatus comprising first, second and third mask plates spaced apart from each other along a main longitudinal axis of said apparatus and each having an aperture configuration therethrough, means for directing a radiant beam at said first mask plate to illuminate in its entirety the aperture configuration therethrough, means interposed between said first and second mask plates and between said second and third mask plates for deflecting the image of the beam transmitted through the aperture configuration in said first plate with respect to the aperture configuration in said second plate and for deflecting the image of the beam transmitted through the aperture configuration in said second plate with respect to the aperture configuration in said third plate to illuminate any specified portion of the aperture configuration in said third plate thereby to define a variable-spot-size beam for propagation toward said work surface, means for demagnifying the image transmitted through the aperture configuration in said third plate and for focusing said image onto said work surface, and means for scanning said demagnified and focused image over said work surface to selectively irradiate portions thereof, wherein the aperture configuration in said third mask plate comprises a single rectangular opening therethrough, and wherein said apparatus further comprises means for controlling said deflecting means to cause said beam to illuminate at least one variable-width portion of said rectangular opening during specified scanning intervals.

Claim 14

Apparatus for scanning a variable-spot-size radiant beam over a work surface to irradiate selected portions of the surface in connection with the fabrication of a microminiature device, said apparatus comprising first, second and third mask plates spaced apart from each other along a main longitudinal axis of said apparatus and each having an aperture configuration therethrough, means for directing a radiant beam at said first mask plate to illuminate in its entirety the aperture configuration therethrough, means interposed between said first and second mask plates and between said second and third mask plates for deflecting the image of the beam transmitted through the aperture configuration in said first plate with respect to the aperture configuration in said second plate and for deflecting the image of the beam transmitted through the aperture configuration in said second plate with respect to the aperture configuration in said third plate to illuminate any specified portion of the aperture configuration in said third plate thereby to define a variable-spot-size beam for propagation toward said work surface, means for demagnifying the image transmitted through the aperture configuration in said third plate and for focusing said image onto said work surface, and means for scanning said demagnified and focused image over said work surface to selectively irradiate portions thereof, wherein the aperture configuration in said third mask plate comprises a single rectangular opening therethrough, and wherein said apparatus further comprises means for controlling said deflecting means to cause said beam to illuminate at least one variable-width portion of said rectangular opening during specified scanning intervals.

Claim 15

Apparatus as in claim 10 further comprising means for projecting the image of the beam transmitted through the first mask plate onto the second mask plate and for projecting the image of the beam transmitted through the second mask plate onto the third mask plate.

Claim 18

A method as in claim 12 further including the step of scanning said beam over said surface in a vector-scan mode of operation.

Claim 21

A method as in claim 14 further including the step of controlling said directing steps to illuminate the aperture configuration in said third mask plate less than a standard prescribed width thereof in the direction of scanning during intervals in which overlapping portions of the surface are being irradiated.

Claim 22

A method as in claim 14 further including the step of controlling said first-mentioned directing step to continuously deflect the image transmitted through the aperture configuration in the second mask plate in a direction opposite to the scanning direction during selected intervals at the beginning and end of an irradiated surface portion to achieve edge sharpness of said portion.