Interposer Manufacturing via Conductive Beads and Planarization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The contact density gap between chips and package carriers in flip chip bonding technology leads to a drop in performance, necessitating the use of interposers as signal transmission mediums to bridge this gap.
Innovation Solution
An interposer is manufactured by filling blind vias on a substrate with conductive beads, forming solder posts, and planarizing the substrate to expose conductive through vias, which are then connected to redistribution layers on both surfaces, enabling efficient signal transmission between the chip and package carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flip chip bonding technology is used to connect chip to package carrier, then electrical connection is achieved, but contact density mismatch occurs between chip and package carrier
Solution Approach 1:
An interposer is introduced as an intermediary component between the chip and package carrier. The interposer contains through-vias with conductive beads that redistribute signals, allowing the chip's high-density contacts to connect to the package carrier's lower-density contacts through the intermediate redistribution layers, thereby resolving the contact density mismatch while maintaining reliable electrical connection
Solution Approach 2:
The patent uses through-vias extending in the vertical dimension (z-axis) to connect redistribution layers on opposite surfaces of the interposer. This three-dimensional approach allows signal redistribution from two-dimensional planar contacts on the chip to accommodate the different contact pattern on the package carrier, solving the density mismatch problem through spatial transformation
2Adaptability or versatility
If interposer is introduced to bridge contact density gap, then signal transmission is enabled, but manufacturing complexity increases
Solution Approach 1:
Conductive beads are placed into through-vias and automatically form electrical connections through self-alignment during the bonding process. The beads' spherical shape and material properties enable them to self-position and create reliable electrical pathways without requiring complex alignment mechanisms, reducing manufacturing complexity while maintaining signal transmission capability
Solution Approach 2:
The interposer combines multiple functions into a single component: mechanical support structure, electrical signal transmission pathway, and contact density redistribution interface. By integrating the through-vias, conductive beads, and redistribution layers into one unified interposer component, the design achieves adaptability without proportionally increasing overall system complexity
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 method enhances signal transmission efficiency by creating conductive through vias with exposed ends on both substrate surfaces, connected to redistribution layers, thereby addressing the contact density mismatch and improving chip-package carrier connectivity.
Implementation Method 1
The solder layers are melted, so that a plurality of solder posts are formed in the blind vias
Data Source
AI summary
A method for manufacturing an interposer includes the following steps. Conductive beads is filled in a blind via of a substrate and a solder layer of each conductive bead is melted so as to form a solder post in the blind via. A metal ball of each conductive bead is inlaid in the corresponding solder post such that the solder post and the metal balls inlaid therein construct a conductive though via. Two surfaces of the substrate are planarized such that two ends of the conductive through via are exposed to the two surfaces of the substrate respectively and are flush with the two surfaces of the substrate respectively. A redistribution layer is manufactured at each surface of the substrate such that the two ends of each conductive through via connect the redistribution layers respectively. Besides, an interposer and a chip package structure applied the interposer are also provided.