Interposer Frame TSV Structure for Fine-Pitch Package Reliability
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Solution Overview
Problem
Existing semiconductor packaging technologies face challenges with large pitch and connectivity limitations, leading to issues such as shorting, CTE mismatch, and delamination of solder joints, which hinder the development of advanced electronic devices.
Innovation Solution
The use of an interposer frame with a substrate and conductive layers to form through substrate vias (TSVs) that have a smaller pitch, improved mechanical strength, and better thermal expansion matching, enhancing connectivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser drilling is used to form connectors, then manufacturing process is simple, but connector pitch is large which limits design flexibility and increases shorting risk
Solution Approach 1:
An interposer substrate is introduced as an intermediary component between the semiconductor die and the package substrate. The interposer provides through-substrate vias (TSVs) that enable fine-pitch interconnections without requiring direct laser drilling between the die and package substrate. This mediator allows the benefits of both simple manufacturing (laser drilling for TSVs) and fine pitch (interposer routing) to be achieved simultaneously.
Solution Approach 2:
The packaging structure is segmented into multiple functional layers: the semiconductor die, the interposer substrate with TSVs, and the package substrate. This segmentation allows each layer to be optimized independently - the interposer handles fine-pitch vertical interconnections through TSVs, while the package substrate provides mechanical support and external I/O. The segmentation enables fine pitch without requiring the entire manufacturing process to achieve that precision.
2Adaptability or versatility
If connector pitch is reduced for better design flexibility, then design flexibility improves, but risk of shorting and delamination increases
Solution Approach 1:
The interposer substrate acts as a mediator that provides mechanical compliance and electrical isolation between the rigid semiconductor die and the package substrate. The TSVs in the interposer are larger in pitch than direct die-to-package connections would require, reducing the risk of shorting. The interposer material can be selected to match thermal expansion coefficients, reducing delamination risk during thermal cycling.
Solution Approach 2:
The patent changes the physical parameters of the interconnection structure by using through-substrate vias with specific diameter and pitch values that are optimized for reliability. The TSV diameter is increased compared to traditional via structures, providing better mechanical strength and electrical conductivity. The pitch between TSVs is controlled to be sufficiently large to prevent shorting while still achieving fine-pitch packaging. These parameter changes enable fine-pitch design without proportionally increasing shorting or delamination risk.
3Strength
If additives are added to substrate to enhance mechanical strength, then mechanical strength improves, but manufacturing complexity increases
Solution Approach 1:
The interposer substrate is constructed as a composite material system, typically consisting of a ceramic core (such as aluminum oxide or aluminum nitride) surrounded by a polymer or epoxy matrix. This composite structure combines the high mechanical strength and thermal conductivity of ceramics with the flexibility and ease of processing of polymers. The composite nature allows the substrate to achieve the required mechanical strength for fine-pitch packaging while maintaining manufacturability through established composite fabrication techniques.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the substrate material to achieve optimal mechanical strength. The ceramic filler content, particle size distribution, and matrix composition are carefully controlled to provide the necessary strength without requiring overly complex manufacturing processes. The substrate thickness and TSV geometry are also optimized to work synergistically with the material properties, allowing moderate-strength materials to achieve the required overall structural strength.
Data Source
AI summary
Some embodiments relate to a package. The package includes a first substrate, a second substrate, and an interposer frame between the first and second substrates. The first substrate has a first connection pad disposed on a first face thereof, and the second substrate has a second connection pad disposed on a second face thereof. The interposer frame is arranged between the first and second faces and generally separates the first substrate from the second substrate. The interposer frame includes a plurality of through substrate holes (TSHs) which pass entirely through the interposer frame. A TSH is aligned with the first and second connection pads, and solder extends through the TSH to electrically connect the first connection pad to the second connection pad.