Back-Side TSV Interconnect Layout for Smaller Bond Pads
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Solution Overview
Problem
The existing integrated chip designs face limitations in routing capability due to the large size of redistribution vias (RV) and conductive bond pads, which restrict the flexibility and performance of metal interconnects.
Innovation Solution
The integration of a back-side through-substrate-via (BTSV) that directly connects metal interconnect layers to a conductive bond pad, reducing the size of the bond pad and enhancing routing capabilities by eliminating the need for a redistribution layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional bond pad structure with thick metal layer is used, then external connectivity is provided, but routing flexibility and performance are restricted due to large size
Solution Approach 1:
The patent introduces a vertical via structure that extends through the substrate thickness, adding a dimensional pathway from the front surface to the back surface. This allows routing to occur in the vertical dimension rather than being constrained to horizontal plane routing, thereby improving routing flexibility without increasing the horizontal bond pad area.
Solution Approach 2:
The connection path is segmented into multiple parts: front surface metal interconnect, vertical through-substrate via, and back surface metal interconnect. This segmentation allows each segment to be optimized independently, enabling smaller overall bond pad area while maintaining routing capability.
2Reliability
If redistribution vias with large size are used, then electrical connection is established, but routing capability is limited
Solution Approach 1:
The via structure transitions from horizontal redistribution in the metal interconnect layers to vertical routing through the substrate thickness. This dimensional change provides additional routing paths that are not constrained by the horizontal layout, thereby improving routing capability while maintaining reliable electrical connection.
Solution Approach 2:
The vertical via acts as an intermediary element that connects the front surface metal interconnect to the back surface metal interconnect. This intermediary structure enables routing flexibility by providing a dedicated vertical pathway that mediates between the front and back surface connections.
3Reliability
If thick metal interconnect layers are used, then conductive connection is provided, but path length is increased reducing performance
Solution Approach 1:
Instead of extending metal interconnect layers horizontally across the substrate surface, the patent inverts the approach by creating a vertical via that penetrates through the substrate thickness. This inversion of the routing direction from horizontal to vertical shortens the signal path length while maintaining conductive connection reliability.
Solution Approach 2:
The signal path is redirected from the horizontal plane to the vertical dimension through the through-substrate via. This dimensional change creates a more direct routing path that reduces the overall signal travel distance, thereby improving performance while maintaining reliable conduction.
Data Source
AI summary
In some embodiments, the present disclosure relates to an integrated chip. The integrated chip includes a first plurality of interconnects within a first inter-level dielectric (ILD) structure disposed along a first side of a first substrate. A conductive pad is arranged along a second side of the first substrate. A first through-substrate-via (TSV) physically contacts an interconnect of the first plurality of interconnects and a first surface of the conductive pad. A second plurality of interconnects are within a second ILD structure disposed on a second substrate. A second TSV extends from an interconnect of the second plurality of interconnects to through the second substrate. A conductive bump is arranged on a second surface of the conductive pad opposing the first surface. The second TSV has a greater width than the first TSV.