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US 6,319,821 B1Granted
Dual damascene approach for small geometry dimension
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsJen-Cheng Liu, Chen-Cheng Kuo, Chia-Shiung Tsai, Hung-Chang Hsieh
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Abstract
A new method is provided of trench etching of the dual damascene structure. The invention replaces the conventional ARC deposition with the deposition of I-line photoresist. The I-line photoresist serves as an anti reflective coating and eliminates, for small opening size, the problems that are encountered with conventional ARC. The deposition characteristics of the I-line photoresist can be adjusted by pre-baking the I-line photoresist prior to deposition thereby controlling its viscosity and density.
Claims19
A method of forming a dual damascene opening by using developer soluble I-line photoresist ARC fill, said dual damascene opening to contain a narrow lower or via section and a wide upper or trench section, comprising the steps of:
- providing a semiconductor substrate having a composite layer of insulation deposited thereon whereby said composite layer comprising a first stop layer deposited over the surface of said substrate over which a first layer of dielectric is deposited over which a second stop layer is deposited over which a second layer of dielectric is deposited over which a third stop layer is deposited whereby said composite layer of dielectric has been patterned and etched thereby forming an opening through said composite layer down to the surface of said first stop layer said opening to have the diameter of said narrow lower or via section of said dual damascene opening;
- depositing a layer of I-line photoresist fill over the surface of said composite layer of insulation thereby including said opening created through said composite layer of insulation, said depositing a layer of I-line photoresist fill is depositing said I-line photoresist to a thickness of between about 2000 and 3000 Angstrom applied through a spin coating process followed by a thermal cure at a temperature of about between about 100 and 200 degrees C. for a time period of between about 30 and 90 seconds to yield a blanket focusing layer when cured of a thickness of about 1500 angstrom;
- performing an I-line photoresist etchback thereby removing said I-line photoresist from the surface of said composite layer of insulation thereby furthermore removing said I-line photoresist from essentially the top half of said opening created through said composite layer of insulation;
- creating the wide upper or trench section of said dual damascene opening;
- removing said third stop layer from the surface of said composite layer of insulation further removing said second stop layer from the bottom of said wide upper or trench section of said dual damascene opening;
- and
- cleaning said substrate by applying DI water.
4 more elements
A method of forming a dual damascene opening by using developer soluble I-line photoresist ARC fill, said dual damascene opening to contain a narrow lower or via section and a wide upper or trench section, comprising the steps of:
- providing a semiconductor substrate;
- depositing a first stop layer of SiN over the surface of said substrate to a thickness of between about 500 and 2000 Angstrom;
- depositing a first layer of dielectric over the surface of said first stop layer deposited to a thickness of between about 5000 and 10000 Angstrom;
- depositing a second stop layer of SiN over the surface of said first layer of dielectric to a thickness of between about 500 and 2000 Angstrom;
- depositing a second layer of dielectric over the surface of said second stop layer deposited to a thickness of between about 5000 and 10000 Angstrom;
- depositing a third stop layer of SiON over the surface of said second layer of dielectric to a thickness of between about 500 and 2000 Angstrom;
- planarizing the surface of said third stop layer by applying a chemical mechanical polishing operation to this surface;
- patterning and etching said layers of third stop layer including said second layer of dielectric including said second stop layer including said first layer of dielectric thereby creating an opening through said patterned and etched layers that has the diameter that is essentially equal to the diameter of said narrow lower or via section of said dual damascene opening;
- performing a dry cleaning followed by a wet cleaning operation;
- depositing a layer of I-line photoresist fill over the surface of said third stop layer thereby including said opening through said patterned and etched layers, said depositing a layer of I-line photoresist fill is depositing said I-line photoresist to a thickness of between about 2000 and 3000 Angstrom applied through a spin coating process followed by a thermal cure at a temperature of about between about 100 and 200 degrees C. for a time period of between about 30 and 90 seconds to yield a blanket focusing layer when cured of a thickness of about 1500 angstrom;
- performing an I-line photoresist etchback thereby removing said I-line photoresist from the surface of said third stop layer thereby furthermore removing said I-line photoresist from essentially the top half of said opening created through said patterned and etched layers;
- patterning and etching said third stop layer thereby including said second layer of dielectric thereby essentially creating the wide upper or trench section of said dual damascene opening;
- reforming a dry cleaning followed by a wet clean operation;
- removing said third stop layer from the surface of said second layer of dielectric further removing said second stop layer from the bottom of said wide upper or trench section of said dual damascene opening;
- and
- cleaning said substrate by applying DI water.
13 more elements
Dependencies are inferred from the claim text.