Pulsed X-ray lithography

Abstract

A method and means for x-ray lithography which utilizes means for producing in a vacuum system a high-temperature plasma from which soft x-rays are emitted. The x-rays pass through a mask exposing an x-ray resist on a substrate to produce the desired pattern on the substrate. The x-ray spectrum has a significant energy in the 1-5 keV range. These x-rays pass through the support layer of the mask, stop in the pattern material (gold) of the mask or, where the pattern material is lacking, are absorbed adequately by the x-ray resist. Since there is very little energy above 5 keV, there is little if any substrate damage due to the x-rays.

What is claimed and desired to be secured by letters patent of the United States is: .[. 
     
       1.  A soft x-ray lithographic system which comprises: a housing;   means for evacuating said housing;   means for producing an x-ray-emitting plasma; and   a mask x-ray-resist substrate combination for replicating a desired pattern on said substrate..].   
     
     
       2. A soft x-ray lithographic system .[.as claimed in claim 1 in.]. which .Iadd.comprises.Iaddend.: .Iadd.a housing;   means for evacuating said housing;   means for producing an x-ray emitting plasma that emits x-rays having an energy from 1-5 keV; and   a mask x-ray resist substrate combination for replicating a desired pattern on said substrate, and   wherein .Iaddend.said x-rays have an .[.energy of from 1 to 5 keV, an.]. emission time of less than 1 microsecond, and a source size of about 1 mm 3 . .[.3. A lithographic system as claimed in claim 1 in which:   said means for producing an x-ray-emitting plasma is a solid metal target upon which a pulsed laser beam is incident..]. .[.4. A lithographic system as claimed in claim 1 in which:   said means for producing an x-ray-emitting plasma is a high electrical energy storage means in combination with a diode within said housing..]. .[.5. A lithographic system as claimed in claim 1 in which   said means for producing an x-ray-emitting plasma is a laser beam focused onto a metal target within said housing..]. .[.6. A method of replicating a pattern on a material which comprises:   placing a mask x-ray absorption pattern relative to an x-ray-resist substrate combination, placing said substrate combination into a housing;   evacuating said housing;   producing an x-ray-emitting plasma within said evacuated housing; and   directing said x-rays onto said substrate combination..]. .[.7. A method as claimed in claim 6 wherein:   said x-ray-emitting plasma is produced by focusing a pulsed laser output onto a metal target within said evacuated housing..]. .[.8. A method as claimed in claim 6 wherein:   said x-ray-emitting plasma is produced by discharging a high electrical storage means through a diode within said housing..]. .[.9. A soft x-ray lithographic system comprising:   means for producing a hot plasma at a temperature above 1 million degrees Celsius, the plasma being composed of matter which emits x-rays at such temperatures; and   means for replicating an image comprising a substrate, a layer of x-ray sensitive material on said substrate, and masking means between said sensitive layer and said plasma-producing means, said masking means containing a representation of the image to be replicated, said representation of the image being formed by the proper combination of areas that are opaque and areas that are transparent to the soft x-rays,   said image being formed on the x-ray-resist by irradiation of the replicating means by the x-rays from the plasma-producing means..]. .[.10. A system as in claim 9, wherein said plasma-producing source comprises a laser and a target spaced therefrom, said target being made from a material which produces a plasma when struck by a laser beam..]. .Iadd.11. A soft x-ray lithographic system which comprises:   a housing;   means for evacuating said housing;   means for producing an x-ray emitting plasma; wherein said means for producing comprises:   a target in said housing;   means for generating a laser beam;   means for focusing said laser beam on said target;   shield means, disposed between said means for focusing and said target, for protecting said means for focusing from material evaporated from said target; and   a mask x-ray resist substrate combination for replicating a desired pattern on said substrate. .Iaddend. .Iadd.12. The system of claim 11, wherein said shield means is a length of rollable material. .Iaddend. .Iadd.13. A soft x-ray lithographic system which comprises:   a housing;   means for evacuating said housing;   a mask x-ray resist substrate combination for replicating a desired pattern on said substrate;   means for producing an x-ray emitting plasma;   wherein said system further comprises a shield means for protecting said substrate combination from material evaporated by said means for producing said x-ray emitting plasma. .Iaddend. .Iadd.14. The system of claim 13, wherein said shield means is a length of rollable material. .Iaddend. .Iadd.15. A soft x-ray lithographic system which comprises:   housing;   means for evacuating said housing;   means including a target upon which a laser beam is incident for producing an x-ray emitting plasma and evaporated target material, said means for producing including means to inhibit said evaporated target material from interfering with the focusing of said laser; and   a mask x-ray resist substrate combination for replicating a desired pattern   
     
     
        on said substrate. .Iaddend. .Iadd.16.  A soft x-ray lithographic system which comprises: a housing;   means for evacuating said housing;   means including a target upon which a laser beam is incident for producing x-rays from an x-ray emitting plasma and evaporated target material; and   a mask x-ray resist substrate combination for replicating a desired pattern on said substrate, said system including means to inhibit said material from interfering with said replicating. .Iaddend. .Iadd.17. A soft x-ray lithographic system as claimed in claim 16 in which:   said x-rays have an energy of from 1 to 5 keV, an emission time of less than 1 microsecond and a source size of about 1 mm 3 ..Iaddend. .Iadd.18. A lithographic system as claimed in claim 16 in which: .Iadd.said means for producing an x-ray emitting plasma is a solid metal target upon which a pulsed laser beam is incident. .Iaddend. .Iadd.19. A lithographic system as claimed in claim 16 in which:   said means for producing an x-ray emitting plasma is a high electrical energy storage means in combination with a diode within said housing. .Iaddend. .Iadd.20. A lithographic system as claimed in claim 16 in which:   said means for producing an x-ray emitting plasma is a laser beam focused   
     
     
        on a metal target within said housing. .Iaddend. .Iadd.21.  A method of replicating a pattern on a material which comprises: placing a mask x-ray absorption pattern relative to an x-ray resist substrate combination;   placing said substrate combination into a housing;   evacuating said housing;   producing an x-ray emitting plasma and evaporated metal within said evacuated housing;   directing said x-rays onto said substrate combination; and   inhibiting said evaporated metal from interfering with said mask. .Iaddend. .Iadd.22. A method as claimed in claim 21 wherein:   said x-ray emitting plasma is produced by focusing a pulsed laser output onto a target within said evacuated housing. .Iaddend. .Iadd.23. A method as claimed in claim 21 wherein:   said x-ray emitting plasma is produced by discharging a high electrical storage means through a diode within said housing. .Iaddend. .Iadd.24. A soft x-ray lithographic system which comprises:   a housing;   means for evacuating said housing;   means, including a target upon which a pulsed laser beam is incident, for producing an x-ray emitting plasma, said target being renewable by translation; and   a mask x-ray resist substrate combination for replicating a desired pattern on said substrate. .Iaddend. .Iadd.25. A method of replicating a pattern on a material which comprises:   placing a mask x-ray absorption pattern relative to an x-ray resist substrate combination;   placing said substrate combination into a housing;   evacuating said housing;   producing an x-ray emitting plasma within said evacuated housing by focusing a pulsed laser output onto a target within said evacuated housing;   directing said x-rays onto said substrate combination; and   renewing said target by translation. .Iaddend. .Iadd.26. A soft x-ray lithographic system comprising:   means for producing a hot plasma at a temperature above 1 million degrees Celsius, the plasma being composed of matter which emits x-rays at such temperature, said plasma-producing source comprises a laser and a target spaced therefrom, said target being made from a material which produces a plasma when struck by a laser beam, said target being renewable by translation; and   means for replicating an image comprising a substrate, a layer of x-ray sensitive material on said substrate, and masking means between said sensitive layer and said plasma-producing means, said masking means containing a representation of the image to be replicated, said representation of the image being formed by the proper combination of areas that are opaque and areas that are transparent to the soft x-rays,   said image being formed on the x-ray resist by irradiation of the replicating means by the x-rays from the plasma-producing means. .Iaddend.   
     
     
        .Iadd.27.  A soft x-ray lithographic system which comprises: a housing;   means for evacuating said housing;   means for producing an x-ray emitting plasma; and   a plurality of mask x-ray resist substrate combination for replicating a desired pattern on said substrate, each positioned in the path of said emitted x-rays;   wherein said x-rays have an energy of from 1 to 5 kev, an emission time of less than 1 microsecond and a source size of about 1 mm 3 . .Iaddend.