Method of forming a cap layer having anti-reflective characteristics on top of a low-k dielectric
AssigneeAdvanced Micro Devices, Inc.
InventorsHartmut Ruelke, Joerg Hohage, Thomas Werner, Frank Mauersberger
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Abstract
A method of forming a multi-layer stack over a low-k dielectric layer is disclosed, wherein the multi-layer stack provides an improved anti-reflective effect and an enhanced protection of the underlying low-k dielectric material during the chemical mechanical polishing process. The multi-layer stack includes silicon dioxide based sub-layers, which may be formed in a highly efficient, non-expensive plasma enhanced deposition method, wherein the optical characteristics may be adjusted by varying a ratio of silane and nitrogen oxide during the deposition.
Claims11
A method, comprising:
- forming a multi-layer stack over a dielectric layer comprised of a low-k dielectric material by forming a layer of silicon dioxide over said low-k dielectric layer;
- forming a silicon-rich oxynitride layer during the formation of said layer of silicon dioxide to thereby adjust at least one optical characteristic o said multi-layer stack so as to reduce back reflection from said low-k dielectric layer;
- forming a resist mask over said silicon-rich oxynitride layer,
- patterning said dielectric layer with resist maks to form a recess in said dielectric layer;
- filling said recess with a metal;
- removing excess metal and said silicon-rich oxynitride layer by chemical mechanical polishing;
- and
- reducing a thicknes of said silicon dioxide based layer during chemical mechanical
- polishing to a thickness of approximately 5—20 nm.
A method of forming a metal region in a low-k dielectric material, the method comprising:
- depositing a silicon dioxide based multi-layer in a plasma ambient over a layer including said low-k dielectric material while controlling optical characteristics of said silicon dioxide based multi-layer, wherein said multi-layer comprises a silicon dioxide layer formed on said dielectric layer with a thickness in the range of approximately 20—120 nm;
- forming a recessed portion by photolithography, wherein said multi-layer reduces back reflection for a specified wavelength:
- filling said recessed portion with a metal;
- and
- removing excess metal and a portion of said multi-layer by chemical mechanical polishing.
A method of forming a metal region in low-k dielectric material, the method comprising:
- depositing a silicon dioxide based multi-layer in a plasma ambient over a layer including said low-k dielectric material while controlling optical characteristics of said silicon dioxide based multi-layer, wherein a silicon-rich oxynitride layer having a thickness in the range of approximately 30—90 nm is formed in the multi-layer by varying a deposition atmosphere during the formation of said silicon dioxide based multi-layer;
- forming a recessed portion by photolithography, wherein said multi-layer reduces back reflection for a specified wavelength;
- filling said recessed portion with a metal;
- and
- removing excess metal and a portion of said multi-layer by chemical mechanical polishing.
A method of forming a metal region in a low-k dielectric material, the method comprising:
- depositing a silicon dioxide based multi-layer in a plasma ambient over a layer including said low-k dielectric material while controlling optical characteristics of said silicon dioxide based multi-layer, wherein a silicon-rich oxynitride layer is formed in the multi-layer;
- forming a nitrogen-depleted protection layer in a surface region of said silicon dioxide based multi-layer, wherein said protection layer is formed by exposure to a nitrogen oxide (N2O) plasma ambient;
- forming a recessed portion by photolithography, wherein said multi-layer reduces back reflection for a specified wavelength;
- filling said recessed portion with metal;
- and
- removing excess metal and at least said protection layer and said silicon-rich oxynitride layer by a chemical mechanical polishing process, wherein a thickness of said silicon dioxide based multi-layer is reduced during said chemical mechanical polishing process to a thickness of approximately 5—20 nm.
Dependencies are inferred from the claim text.