Redistribution Substrate Metal Gradient for Crack-Resistant Packaging
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Solution Overview
Problem
Existing semiconductor packages face challenges in achieving improved structural stability and reliability, particularly in reducing the size and enhancing the integrity of the connections between semiconductor chips and printed circuit boards.
Innovation Solution
A redistribution substrate is designed with a specific metal layer structure that includes a first metal with a higher concentration in a vertically overlapping portion and a second metal with a lower concentration in a surrounding portion, along with a wiring pattern and insulating layers to enhance structural stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is formed covering the wiring pattern to improve reliability, then crack prevention during heat treatment is enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent employs a composite metal layer structure consisting of a first metal layer (e.g., Cu, Al, or Ag) and a second metal layer (e.g., Ni, Pd, or Pt) with different material properties. The first metal layer provides electrical conductivity, while the second metal layer provides crack resistance and oxidation protection. This composite structure resolves the contradiction by achieving improved reliability through material composition rather than process complexity.
Solution Approach 2:
The patent applies different metal materials at different locations and depths within the metal layer. The first metal is positioned closer to the wiring pattern for electrical connection, while the second metal is positioned at the upper surface for environmental protection and mechanical strength. This local differentiation of material quality achieves reliability improvement without requiring complex manufacturing processes.
2Strength
If the metal layer thickness is increased to improve crack resistance, then structural stability is enhanced, but the electrical connection quality may deteriorate
Solution Approach 1:
The patent divides the metal layer into multiple segments or sub-layers, each with specific thickness and material composition. The first metal layer has a thickness optimized for electrical conductivity, while the second metal layer has a thickness optimized for crack resistance. This segmentation allows each layer to perform its specific function optimally without compromising the other, resolving the contradiction between strength and electrical connection quality.
Solution Approach 2:
By using composite metal layers with different material properties and optimized thickness ratios, the patent achieves both crack resistance and electrical connection quality. The first metal layer (e.g., Cu with high conductivity) maintains electrical performance, while the second metal layer (e.g., Ni with high strength) provides crack resistance, eliminating the need to increase overall thickness.
Data Source
AI summary
A redistribution substrate includes first and second insulating layers; a wiring layer, and a metal layer. The wiring pattern includes a via portion penetrating the first insulating layer and a pad portion on the via portion, the pad portion extending onto an upper surface of the first insulating layer. The metal layer covers an upper surface of the wiring pattern. The second insulating layer is provided on the first insulating layer and covers the pad portion and the metal layer. The wiring pattern includes a first metal. The metal layer includes the first metal and a second metal. The metal layer includes a first portion vertically overlapping the pad portion, and a second portion surrounding the first portion, and a concentration of the first metal in the first portion of the metal layer is greater than a concentration of the first metal in the second portion of the metal layer.