Chemical-mechanical alignment mark and method of fabrication
AssigneeCypress Semiconductor Corporation
InventorRoger F. Caldwell
Life of this patent
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Abstract
A method for forming an alignment mark during semiconductor device manufacturing. A first alignment mark having a first step height is formed in a semiconductor substrate. An interlayer dielectric is formed over the alignment mark and planarized to a first thickness. During contact/via etch an opening is formed through the first dielectric layer away from the first alignment mark. The opening is then filled with a material until the material in the bottom of the opening has a thickness less than thickness of the planarized dielectric layer.
Claims23
A method for forming a chemical-mechanical alignment mark comprising the steps of:
- forming a first alignment mark having a first step height;
- forming a first layer having a first thickness over said first alignment mark;
- forming an opening in said first layer, away from said first alignment mark;
- filling said opening with a second layer until said opening is filled to a second thickness less than said first thickness of said first layer, such difference between said first thickness and said second thickness forming a step height of said chemical-mechanical alignment mark.
A method of forming a chemical-mechanical alignment mark comprising the steps of.
- forming an alignment mark in a substrate, wherein said alignment mark has a first step;
- forming a dielectric layer over said alignment mark;
- planarizing said dielectric layer to a first thickness;
- etching an opening away from said alignment mark through said dielectric layer;
- and
- depositing a second thickness of a conductive layer over said dielectric layer and into said opening wherein said second thickness is less than said first thickness.
A method of forming a chemical-mechanical polishing alignment mark comprising the steps of:
- forming alignment mark in a silicon substrate, said alignment mark comprising a first step height;
- forming a layer comprising polysilicon over said substrate, including said alignment mark;
- forming a dielectric layer over said layer comprising polysilicon;
- planarizing said dielectric layer to a first thickness above said layer comprising polysilicon;
- etching an opening through said dielectric layer to said layer comprising polysilicon, wherein said opening is formed away from said alignment mark;
- conformily depositing a conductive layer comprising tungsten over said dielectric layer and over said layer comprising polysilicon in said opening wherein said conductive layer is deposited to a second thickness, wherein said second thickness is less than said first thickness;
- and
- chemically-mechanically polishing said conductive layer so as to form a second alignment mark having a second step height in said conductive layer in said opening.
A method of forming an alignment mark, comprising the steps of:
- forming a first layer;
- globally planarizing said first layer;
- etching an opening in said first layer;
- and
- filling said opening with a second layer of a different material, so that the height difference between said first layer and said second layer forms the alignment mark.
Dependencies are inferred from the claim text.