Method of forming planarized coatings on contact hole patterns of various duty ratios

A method for forming a planar photoresist layer on a via hole pattern in a dual damascene process comprising:

• (a) providing a substrate with a stack of layers formed thereon, said stack comprising an upper dielectric layer and a lower etch stop layer, said dielectric layer includes a via hole pattern having holes in high and low duty ratio regions,
• (b) coating a first photoresist layer on said dielectric layer, said photoresist is baked at a temperature such that the photoresist reflows and fills said via holes,
• (c) removing said photoresist from the surface of said dielectric layer and forming a recessed layer of said first photoresist in said holes,
• (d) hardening said recessed photoresist layer, and
• (e) coating a second photoresist layer on said substrate that forms a uniform thickness over holes in both high duty ratio regions and in low duty ratio regions.

A method for forming a planar photoresist layer on a contact hole pattern in fabricating a metal-insulator-metal (MIM) capacitor comprising:

• (a) providing a substrate with a dielectric layer formed thereon, said dielectric layer contains a contact hole pattern having holes in high and low duty ratio regions,
• (b) depositing a conformal metal layer on said dielectric layer and in said holes,
• (c) coating a first photoresist layer on said metal layer, said photoresist is baked at a temperature such that the photoresist reflows and fills said contact holes,
• (d) removing said photoresist from the surface of said metal layer and forming a recessed layer of said photoresist in said holes,
• (e) hardening said recessed photoresist layer, and
• (f) coating a second photoresist layer on said metal layer that forms a uniform thickness over holes in both high duty ratio regions and in low duty ratio regions.