Method for fabricating dual damascence structures using photo-imprint lithography, methods for fabricating imprint lithography molds for dual damascene structures, materials for imprintable dielectrics and equipment for photo-imprint lithography used in dual damascence patterning
View Patent ↗The process of producing a dual damascene structure used for the interconnect architecture of semiconductor chips. More specifically the use of imprint lithography to fabricate dual damascene structures in a dielectric and the fabrication of dual damascene structured molds.
1. An imprint lithography mold comprising a multilevel mold containing a negative relief image of a dual damascene structure having:
a substrate coated with a trilayer hardmask stack;
said trilayer hardmask stack having a plurality of layers including:
a bottom hardmask layer, having a composition suitable to be an etchstop layer,
said bottom layer being in contact with said substrate;
a middle hardmask layer having a composition suitable to print a negative line-level pattern, said line level pattern forming the basis for the horizontal line levels existing within said mold, said middle layer being in contact with an exposed surface of said bottom etchstop layer;
a top layer having a composition suitable to print a negative via level pattern and having an upper and a lower surface, said lower surface of said top layer being in contact with an exposed surface of said middle layer;
said upper surface of said top layer of said trilayer hardmask stack having a removable negative via level pattern which forms a topographical pattern, said pattern forming the basis for the multilevel vertical depth trenches existing within said mold;
a resist coating on said upper surface of said top layer of said hardmask stack, said resist coating being patterned with a negative line level pattern;
said mold containing multilevel mold elements through said trilayer hardmask stack and said substrate aligned with and corresponding to said negative line level pattern and with and to said negative via level pattern resulting in a negative of a dual damascene-like structure.
2. The multilevel mold defined in claim 1 , wherein said mold substrate is a material selected from the group consisting of quartz, silicon, pyrex, Indium Tin Oxide, GaAs and InP.
3. The mold defined in claim 1 in which a surface of said mold is treated with a low surface energy component.
4. The mold defined in claim 3 wherein said low surface energy component is a fluorinated self assembly monolayer comprising a fluorinated alkyl halosilane, fluorinated alkyl alkoxysilane, fluorinated alkyl acetoxy silane and tridecafluorooctyltrichlorosilane.
5. The mold defined in claim 1 wherein alignment marks are incorporated into a structure of said mold, wherein said alignment marks comprise diffractive grating, moire fringe, chirped, verniers and box-in-box patterns.
6. The mold defined in claim 1 wherein said mold comprises a plurality of materials and wherein one or more of said materials is patterned with alignment marks.
7. The mold defined in claim 1 which incorporates recessed regions used to confine displaced material.
8. The mold defined in claim 7 which incorporates recessed regions on the periphery of the imprint pattern.
9. The mold defined in claim 8 which incorporates a recess region that is pre-measured in order to provide a reference surface for substrate-mold gap control.
10. The mold defined in claim 1 which is a second-generation mold that is fabricated by embossing a master mold into a curable material that is coated on a second-generation mold.