Selective patterning of metallization on a dielectric substrate
AssigneeMicroelectronics and Computer Technology Corporation
InventorsCharles W. C. Lin, Randy L. German
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Abstract
A method of selectively fabricating metallization on a dielectric substrate is disclosed. A seed layer is sputtered on a polymer dielectric, a patterned photoresist mask is disposed over the seed layer, exposed portions of the seed layer are etched, the photoresist is stripped, and copper is deposited without a mask by electroless plating on the unetched seed layer to form well-adhering high density copper lines without exposing the photoresist to the electroless bath.
Claims27
A method of selectively patterning metal on a dielectric substrate, comprising the following steps in the sequence set forth:
- depositing a seed layer on a dielectric substrate wherein the seed layer is autocatalytic to an electrically conductive metal whereas the dielectric substrate is non-autocatalytic to the metal;
- overlaying a resist mask on the seed layer wherein the resist mask has a pattern which covers portions of the seed layer whereas a plurality of openings in the resist mask expose other portions of the seed layer;
- etching the exposed portions of the seed layer;
- removing the resist mask thereby exposing the unetched portions of the seed layer which correspond to the pattern of the resist mask;
- and
- depositing the metal on the unetched portions of the seed layer without depositing the metal on the dielectric substrate and without using a mask wherein the deposited metal corresponds to the pattern and the seed layer provides adhesion between the dielectric substrate and the deposited metal.
A method of selectively fabricating metallization on a polymer substrate, comprising the following steps in the sequence set forth:
- depositing an adhesive seed layer on a polymer substrate wherein the seed layer is autocatalytic to an electrically conductive metal whereas the polymer substrate is non-autocatalytic to the metal;
- overlaying a photoresist mask at least 0.1 microns thick on the seed layer;
- forming a pattern in the photoresist mask which covers portions of the seed layer wherein a plurality of openings in the photoresist mask expose other portions of the seed layer;
- etching the exposed portions of the seed layer;
- removing the photoresist mask thereby exposing the unetched portions of the seed layer which correspond to the pattern of the photoresist mask;
- and
- depositing the metal on the unetched portions of the seed layer without depositing the metal on the polymer substrate and without using a mask wherein the deposited metal corresponds to the pattern and the unetched seed layer provides adhesion between the deposited metal and the polymer substrate.
A method of electrolessly depositing copper in a pattern on a polymer layer, comprising the following steps in the sequence set forth:
- sputtering a seed layer on a planar polymer layer, the seed layer being autocatalytic to copper and comprising an adhesive bottom layer of titanium or chromium and a copper layer over the bottom layer whereas the polymer layer is non-autocatalytic to copper;
- overlaying a layer of positive working photoresist on the seed layer;
- patterning the photoresist to form a pattern which covers portions of the seed layer wherein a plurality of openings in the photoresist expose other portions of the seed layer;
- etching the exposed seed layer portions;
- stripping the photoresist thereby exposing the unetched portions of the seed layer which correspond to the pattern of the photoresist;
- and
- electrolessly depositing copper on the unetched seed layer without depositing the copper on the polymer layer wherein the copper is at least 5 microns thick and corresponds to the pattern with a line density of at least 300 lines per inch, and the seed layer provides adhesion between the deposited copper and the polymer layer.
A method of selectively patterning metal on a dielectric substrate, comprising the following steps in the sequence set forth:
- depositing a seed layer on a dielectric substrate wherein the seed layer and the dielectric substrate are non-autocatalytic to an electrically conductive metal;
- overlaying a resist mask on the seed layer wherein the resist mask has a pattern which covers portions of the seed layer whereas a plurality of openings in the resist mask expose other portions of the seed layer;
- etching the exposed portions of the seed layer;
- removing the resist mask thereby exposing the unetched portions of the seed layer which correspond to the pattern of the resist mask;
- rendering the unetched portions of the seed layer catalytic to the metal;
- and
- depositing the metal on the unetched portions of the seed layer without depositing the metal on the dielectric substrate and without using a mask wherein the deposited metal corresponds to the pattern and the seed layer provides adhesion between the dielectric substrate and the deposited metal.
Dependencies are inferred from the claim text.