Wafer-Based Flip Chip Package Routing for Fine-Pitch ICs
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Solution Overview
Problem
Electronic systems require higher circuit density and smaller form factors with fine pitch lead spacing, which conventional interconnect substrates struggle to support due to limitations in signal routing capability, especially for advanced applications like automotive systems.
Innovation Solution
A multilevel metallization structure with multiple levels of conductive metal traces and vias, along with polyimide insulator material, is used to facilitate flip chip attachment of semiconductor dies, allowing for reduced terminal spacing and increased terminal count, and improved routing capabilities, integrated within a package structure that encloses the semiconductor die and portions of the metallization structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional interconnect substrates are used, then manufacturing is simpler, but signal routing capability is insufficient for fine pitch lead spacing and high circuit density
Solution Approach 1:
The patent transitions from a conventional planar interconnect substrate to a multilevel metallization structure built on a semiconductor wafer, adding vertical dimensionality through multiple metal layers and vias. This enables fine pitch lead spacing and high circuit density by routing signals through multiple levels rather than relying solely on planar traces, thereby improving signal routing capability while maintaining manufacturability through established semiconductor fabrication processes.
2Quantity of substance
If semiconductor die terminal spacing is reduced and terminal count is increased, then circuit density is improved, but conventional interconnect substrates cannot support the routing requirements
Solution Approach 1:
The multilevel metallization structure provides multiple routing planes through stacked metal layers connected by vias, enabling increased terminal count and reduced terminal spacing. Signals can be distributed across multiple levels, allowing higher circuit density on the semiconductor die to be properly routed without exceeding the capabilities of conventional single-plane interconnect substrates.
Solution Approach 2:
The interconnect structure is segmented into multiple discrete metal layers, each capable of carrying independent signal routes. This segmentation allows complex routing patterns to be distributed across multiple levels, supporting increased terminal count and reduced spacing by providing parallel routing pathways that prevent signal congestion.
3Manufacturing precision
If a multilevel metallization structure is implemented, then fine pitch lead spacing and high circuit density are achieved, but manufacturing process complexity increases
Solution Approach 1:
The patent leverages the semiconductor wafer itself as the substrate for the multilevel metallization structure, allowing the wafer fabrication process to serve dual purposes: creating the semiconductor die and building the interconnect structure. This self-service approach uses existing semiconductor manufacturing capabilities (deposition, etching, planarization) to create the multilevel metallization, reducing the need for separate, complex packaging processes and maintaining ease of manufacture despite the increased precision requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables increased circuit density and fine pitch feature spacing, enhancing routing capabilities and supporting advanced semiconductor die packaging without the need for separate laminated routing substrates, facilitating integration in a single production facility.
Implementation Method 1
The semiconductor die is flip chip attached to the first side of the multilevel metallization structure with conductive features soldered to respective conductive metal pads of the final level of the multilevel metallization structure
Data Source
AI summary
An electronic device includes a multilevel metallization structure, a semiconductor die, and a package structure. The multilevel metallization structure has multiple levels of conductive metal traces and vias and polyimide insulator material, including a first level along a first side and a final level along a second side. The first level includes conductive metal leads with exposed surfaces along the first side, and the final level includes conductive metal pads with exposed surfaces along the second side. The semiconductor die is flip chip attached to the first side of the multilevel metallization structure with conductive features connected to respective conductive metal pads of the final level of the multilevel metallization structure, and the package structure encloses the semiconductor die and portions of the first side of the multilevel metallization structure.