Fan-Out RDL Rivet Structure for Delamination Resistance
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Solution Overview
Problem
Conventional multi-chip module technologies face challenges with limited minimum line spacing, mechanical stress, warpage, and delamination issues due to differing mechanical properties of RDL layers, underfills, metal layers, and solder structures, which affect the reliability and accuracy of chip-to-chip interconnects.
Innovation Solution
The introduction of rivets in the fan-out redistribution layer (RDL) structure, comprising conductor pads, traces, and vias, which act as mechanical reinforcements to resist delamination by counteracting warpage-induced bending moments and stresses, thereby enhancing the structural integrity of the polymer layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-chip module technologies are used with RDL layers, underfills, and solder structures, then chip-to-chip interconnects can be established, but mechanical stress and warpage occur due to differing mechanical properties of the layers
Solution Approach 1:
The patent modifies the mechanical properties of the RDL structure by introducing rivets with specific material compositions and geometric parameters. The rivets have controlled diameter, length, and material modulus that differ from the surrounding RDL layers, creating a composite structure with optimized mechanical properties that reduces warpage and stress while maintaining interconnect reliability.
Solution Approach 2:
The patent creates a composite structure by embedding rivets within the RDL layers. This composite construction combines the electrical conductivity of the RDL material with the mechanical reinforcement of the rivet material, producing a hybrid structure that simultaneously provides electrical interconnection and mechanical stress resistance.
2Reliability
If conventional RDL structures are used without reinforcement, then manufacturing is simpler, but delamination occurs due to warpage-induced bending moments and stresses
Solution Approach 1:
The patent divides the continuous RDL structure into segmented regions by introducing discrete rivet elements at strategic locations. These rivets act as independent reinforcement units that locally counteract delamination forces without requiring reinforcement of the entire RDL structure, thus managing complexity through localized interventions.
Solution Approach 2:
The rivets serve as intermediary elements between the RDL layers and the underlying substrate. They mediate the mechanical stresses and bending moments that would otherwise cause delamination, transferring and distributing these forces through their anchored structure that extends into both the RDL layer and the substrate.
3Strength
If rivets are added to the fan-out RDL structure, then delamination is resisted and structural integrity is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by placing rivets only in specific regions where delamination risk is highest, rather than uniformly throughout the entire RDL structure. The rivets are positioned at critical stress points and boundaries between different material layers, providing targeted reinforcement where mechanically most needed while leaving other regions unchanged.
Data Source
AI summary
Various semiconductor chip packages are disclosed. In one aspect, a semiconductor chip package is provided that includes a fan-out redistribution layer (RDL) structure that has plural stacked polymer layers, plural metallization layers, plural conductive vias interconnecting adjacent metallization layers of the metallization layers, and plural rivets configured to resist delamination of one or more of the polymer layers. Each of the plural rivets includes a first head, a second head and a shank connected between the first head and the second head. The first head is part of one of the metallization layers. The shank includes at least one of the conductive vias and at least one part of another of the metallization layers.