Enhanced Capture Pads for TSV Current Crowding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capture pad designs in 3D semiconductor stacks suffer from current crowding, limiting the current capacity due to inadequate current spreading at the interface between through silicon vias and capture pads.
Innovation Solution
The formation of enhanced capture pads with a recessed through silicon via design, featuring insulator islands dispersed in metal, which are self-aligned and have an all-metal portion following the outline of the TSVs, reducing current crowding by improving current spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capture pad designs are used, then the structure is simple, but current crowding occurs and current capacity is limited
Solution Approach 1:
The capture pad is segmented into multiple functional zones: an all-metal portion directly contacting the TSV, insulator islands dispersed in the metal, and a transition to the outer metal region. This segmentation allows different regions to perform different functions - the all-metal portion ensures low-resistance electrical contact while insulator islands provide mechanical support and stress relief, resolving the current crowding issue without requiring complete structural redesign
Solution Approach 2:
Different regions of the capture pad are given different material compositions and properties. The inner region has all-metal composition for optimal electrical contact, while the outer region transitions to metal with dispersed insulator islands. This local differentiation optimizes current distribution at the TSV interface while maintaining overall structural integrity and reducing current crowding effects
2Reliability
If the capture pad area is increased to improve current spreading, then current capacity improves, but the footprint of the semiconductor device increases
Solution Approach 1:
The capture pad employs a composite structure combining metal and insulator materials in a dispersed phase arrangement. The metal provides electrical conductivity while insulator islands provide mechanical support and stress distribution. This composite approach enhances current spreading capability within a compact area, improving current capacity without proportionally increasing the device footprint
Data Source
AI summary
Method of forming a capture pad on a semiconductor substrate. The method includes providing a semiconductor substrate having an active side and an inactive side and having a plurality of unfilled TSVs extending between the active side and the inactive side; filling the TSVs with a metal; defining capture pad areas on at least one of the active side and the inactive side adjacent to the TSVs, the defined capture pad areas comprising insulator islands and open areas; filling the open areas with the same metal to form a capture pad in direct contact with each of the TSVs, each of the capture pads having an all metal portion that follows an outline of each of the TSVs.