Fabrication Process and Structure of Fine Pitch Traces for a Solid State Diffusion Bond on Flip Chip Interconnect
AssigneeCompass Technology Company Limited
InventorsKelvin Po Leung Pun, Chee Wah Cheung
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Abstract
A method to produce a semiconductor package or system-on-flex package comprising bonding structures for connecting IC/chips to fine pitch circuitry using a solid state diffusion bonding is disclosed. A plurality of traces is formed on a substrate, each respective trace comprising at least four different conductive materials having different melting points and plastic deformation properties, which are optimized for both diffusion bonding of chips and soldering of passives components.
Claims20
A method of manufacturing a substrate for diffusion bonding comprising:
- providing a flexible substrate;
- and
- forming a plurality of traces on said flexible substrate, said forming comprising:
- electrolytically plating copper traces on said flexible substrate, said copper traces having a pitch of between about 0.8 μm and 30 μm;
- and
- immersion plating a tin layer on top and side surfaces of said plurality of copper traces to complete said substrate suitable for diffusion bonding.
A method of manufacturing a semiconductor package comprising:
- providing a substrate and a die having at least one gold bump thereon;
- forming a plurality of traces on said substrate, said forming comprising:
- electroless plating a seed layer on said substrate;
- electrolytically plating copper traces on said seed layer, said copper traces having a pitch of between about 8 μm and 30 μm, with a line width of about 4 μm and spacing of about 4 μm;
- immersion plating a tin layer on top and side surfaces of said plurality of copper traces;
- and
- diffusion bonding said die to at least one of said plurality of traces by thermal compression of said at least one gold bump to complete said semiconductor package.
Dependencies are inferred from the claim text.