Patent Number: 045368821
Section: claims

1. A method of making an X-ray mask for X-ray lithography comprising the steps of: providing a substrate for supporting the mask membrane of the X-ray mask during fabrication thereof;  depositing a thin layer of material which is opaque to X-ray or charged particle radiation on said substrate, said thin layer having a thickness less than that of said substrate;  patterning said thin layer to form a mask pattern;  applying a mask membrane layer of a high X-ray transmissive material over said patterned thin layer; and  removing at least a portion of the substrate to form an X-ray mask. 2. A method as defined in claim 1, further comprising the step of depositing an etch stop layer or a parting layer between said substrate and said thin layer to facilitate the removal of said substrate. 3. A method as defined in claim 2, further comprising the step of depositing a capping layer between said substrate and said etch stop layer or parting layer. 4. A method as defined in claim 1, further comprising the step of depositing an adhesion layer above and below said thin layer to promote adhesion of said thin layer to the adjacent layers. 5. A method as defined in claim 1, wherein said step of removing a portion of said substrate results in the retention of a portion of said substrate on peripheral sides of the X-ray mask. 6. A method as defined in claim 1, wherein said step of removing at least a portion of said substrate results in the removal of the entire substrate. 7. A method as defined in claim 6, further comprising the step of bonding a rigid support to said membrane layer, and wherein said step of removing a portion of said substrate is performed subsequently to the step of bonding of said rigid support. 8. A method as defined in claim 1, wherein said deposition of said thin layer is performed by vacuum deposition. 9. A method as defined in claim 1, wherein said step of applying a mask membrane layer comprises spinning a polimide film on said patterned layer.