Two-layered TSI process for dual damascene patterning
First Claim
1. A method of forming a dual damascene pattern employing a single photolithographic top surface imaging process with a dual layered photoresist comprising the steps of:
- providing a substrate having a composite layer of insulation deposited thereon whereby said composite layer comprises a first layer of dielectric separated from a second layer of dielectric by an intervening intermediate layer of etch-stop material comprising silicon nitride having a thickness between about 500 to 2000 Å
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forming a first layer of silylation photoresist on said composite layer of dielectric insulation;
hole patterning said first layer of silylation photoresist by exposing said photoresist using a photo mask;
performing a hard bake of said first layer of silylation photoresist;
treating a surface portion of said first layer of silylation photoresist with a silylation process thereby forming a silylated layer of silylation regions in said first layer of silylation photoresist;
dry etching portions of said first layer of silylation photoresist using said silylated layer of said first layer of silylation photoresist as a mask;
forming a second layer of photoresist on said first layer of silylation photoresist covering said substrate;
line patterning said second layer of photoresist by exposing said second layer of photoresist using a photo mask;
performing wet development to remove portions of said second layer of photoresist to form line pattern in said second layer of photoresist;
etching through said second layer of dielectric underlying said first layer of silylation photoresist using said silylated layer of said first layer of silylationphotoresist as a mask thereby transferring said hole pattern in said first layer of silylation photoresist into said second layer of dielectric;
etching through said intermediate etch-stop layer underlying said second layer of dielectric using said silylated layer of said first layer of silylation photoresist as a mask thereby transferring said hole pattern in said first layer of silylation photoresist into said intermediate layer of dielectric;
etching said first layer of silylation photoresist through said line pattern in said second layer of photoresist thereby transferring said line pattern from said second layer of photoresist into said first layer of photoresist, while at the same time, partially etching said second layer of photoresist, thus reducing the thickness of said second layer of photoresist, and forming a multilayered photoresist structure comprising said second and first layers of photoresist having said line pattern therein;
etching said composite layer of insulation through said multilayered photoresist structure thereby transferring said line pattern in said first layer of silylation photoresist into said second layer of dielectric to form a line trench,and simultaneously transferring said hole pattern in said intermediate layer of dielectric into said first layer of dielectric to form a contact hole;
ashing and wet stripping said multilayered photoresist structure;
forming a film of metal into said trench and said hole to form a dual damascene structure; and
polishing said film of metal.
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Accused Products
Abstract
A new method is disclosed for forming dual damascene patterns using a silylation process. A substrate is provided with a tri-layer of insulation formed thereon. A first layer of silylation photoresist is formed on the substrate and is imaged with a hole pattern by exposure through a mask. Using a silylation process, which greatly improves the depth of focus by reducing reflections from the underlying substrate, the regions in the first photoresist adjacent to the hole pattern are affixed to form top surface imaging mask. The hole pattern is then etched in the first photoresist. A second layer of photoresist is formed, and is imaged with a line pattern aligned with the previous hole pattern by exposure through a mask. The line pattern in the second photoresist is etched. The hole pattern in the first photoresist is transferred into the top layer of composite insulation first and then into the middle etch-stop layer by successive etching. The line pattern in the second photoresist layer is transferred into the first photoresist layer through a subsequent resist dry etching process. Finally, the line pattern and the hole pattern are transferred simultaneously into the top and lower layers of the composite insulation layer, respectively, through a final dry oxide etching. Having thus formed the integral hole and line patterns into the insulation layer, metal is deposited into the dual damascene pattern. Any excess metal on the surface of the insulating layer is then removed by any number of ways including chemical-mechanical polishing, thereby planarizing the surface and readying it for the next semiconductor process.
125 Citations
27 Claims
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1. A method of forming a dual damascene pattern employing a single photolithographic top surface imaging process with a dual layered photoresist comprising the steps of:
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providing a substrate having a composite layer of insulation deposited thereon whereby said composite layer comprises a first layer of dielectric separated from a second layer of dielectric by an intervening intermediate layer of etch-stop material comprising silicon nitride having a thickness between about 500 to 2000 Å
;forming a first layer of silylation photoresist on said composite layer of dielectric insulation; hole patterning said first layer of silylation photoresist by exposing said photoresist using a photo mask; performing a hard bake of said first layer of silylation photoresist; treating a surface portion of said first layer of silylation photoresist with a silylation process thereby forming a silylated layer of silylation regions in said first layer of silylation photoresist; dry etching portions of said first layer of silylation photoresist using said silylated layer of said first layer of silylation photoresist as a mask; forming a second layer of photoresist on said first layer of silylation photoresist covering said substrate; line patterning said second layer of photoresist by exposing said second layer of photoresist using a photo mask; performing wet development to remove portions of said second layer of photoresist to form line pattern in said second layer of photoresist; etching through said second layer of dielectric underlying said first layer of silylation photoresist using said silylated layer of said first layer of silylation photoresist as a mask thereby transferring said hole pattern in said first layer of silylation photoresist into said second layer of dielectric; etching through said intermediate etch-stop layer underlying said second layer of dielectric using said silylated layer of said first layer of silylation photoresist as a mask thereby transferring said hole pattern in said first layer of silylation photoresist into said intermediate layer of dielectric; etching said first layer of silylation photoresist through said line pattern in said second layer of photoresist thereby transferring said line pattern from said second layer of photoresist into said first layer of photoresist, while at the same time, partially etching said second layer of photoresist, thus reducing the thickness of said second layer of photoresist, and forming a multilayered photoresist structure comprising said second and first layers of photoresist having said line pattern therein; etching said composite layer of insulation through said multilayered photoresist structure thereby transferring said line pattern in said first layer of silylation photoresist into said second layer of dielectric to form a line trench, and simultaneously transferring said hole pattern in said intermediate layer of dielectric into said first layer of dielectric to form a contact hole; ashing and wet stripping said multilayered photoresist structure; forming a film of metal into said trench and said hole to form a dual damascene structure; and polishing said film of metal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 19)
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18. A method of forming a dual damascene pattern employing a single photolithographic top surface imaging process with a dual layered photoresist comprising the steps of:
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providing a substrate having a composite layer of insulation deposited thereon whereby said composite layer comprises a top layer of dielectric separated from a bottom layer of dielectric by an intervening intermediate layer of dielectric; forming a first layer of silylation photoresist on said composite layer; hole patterning and etching said hole into said first layer of silylation photoresist; silylating said first layer of silylation photoresist to form a silylated glass mask comprising said hole pattern; transferring said hole pattern in said silylated layer into the top layer of said composite layer of insulation by etching; transferring said hole pattern in said top layer into the intermediate etch-stop layer of said composite layer of insulation by etching; forming a second layer of photoresist on said first layer of silylation photoresist; line patterning said second layer of photoresist; transferring said line pattern in said second layer of photoresist into said first layer of silylation photoresist by etching; transferring said line pattern in said first layer of silylation photoresist into said top layer of insulation to form a line trench, and simultaneously transferring said hole pattern in said intermediate layer of insulation into said bottom layer of insulation to form a contact hole; and forming a film of metal into said trench and said hole to form a dual damascene structure; and polishing said film of metal.
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20. A method of forming a dual damascene pattern employing a single photolithographic top surface imaging process with a dual layered photoresist comprising the steps of:
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providing a substrate having a composite layer of insulation deposited thereon whereby said composite layer comprises a top layer of dielectric separated from a bottom layer of dielectric by an intervening intermediate layer of dielectric comprising silicon nitride with a thickness between about 500 to 2000 Å
;forming a first layer of silylation photoresist on said composite layer; hole patterning and etching said hole into said first layer of silylation photoresist; silylating said first layer of silylation photoresist to form a silylated glass mask comprising said hole pattern; transferring said hole pattern in said silylated layer into the top layer of said composite layer of insulation by etching; transferring said hole pattern in said top layer into the intermediate etch-stop layer of said composite layer of insulation by etching; forming a second layer of photoresist on said first layer of silylation photoresist; line patterning said second layer of photoresist; transferring said line pattern in said second layer of photoresist into said first layer of silylation photoresist by etching; transferring said line pattern in said first layer of silylation photoresist into said top layer of insulation to form a line trench, and simultaneously transferring said hole pattern in said intermediate layer of insulation into said bottom layer of insulation to form a contact hole; and forming a film of metal into said trench and said hole to form a dual damascene structure; and polishing said film of metal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification