Thin Flip Chip Package With Insulating Recess For Heat Dissipation Paste
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Solution Overview
Problem
Conventional thin flip chip package structures face challenges in heat dissipation due to the need for a dam to prevent sealing resin from polluting the heat dissipation paste, which complicates the manufacturing process and increases costs, while insufficient dams lead to resin flow into the heat dissipation area.
Innovation Solution
A substrate design with an insulating layer comprising a first and second portion of different thicknesses, where the second portion is coplanar with the first, allowing the sealing resin to be contained and eliminating the need for a dam, while the recess in the first portion accommodates heat dissipation paste for enhanced thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dam is formed on the substrate to block sealing resin, then the heat dissipation paste is protected from pollution, but the manufacturing complexity and cost increase
Solution Approach 1:
The insulating layer is divided into two distinct portions: a first insulating portion that contacts the heat dissipation paste and a second insulating portion that is coplanar with the first. This segmentation allows the sealing resin to be contained by the coplanar second portion without requiring an additional dam structure, thus protecting the heat dissipation paste while simplifying the overall substrate structure.
Solution Approach 2:
The insulating layer serves multiple functions: it provides electrical insulation, contains the sealing resin through its coplanar second portion, and protects the heat dissipation paste. By integrating these functions into a single multi-functional insulating layer structure, the need for separate dam structures is eliminated, reducing manufacturing complexity while maintaining reliability.
2Reliability
If the dam height is increased to block sealing resin, then the heat dissipation paste is protected, but the chip bump connection with substrate becomes difficult
Solution Approach 1:
The insulating layer is segmented into a first portion with greater thickness that contacts the heat dissipation paste and a second coplanar portion. This segmentation provides effective sealing resin containment without requiring a tall dam structure, ensuring both heat dissipation paste protection and easy chip bump connection to the substrate.
3Ease of manufacture
If the dam height is reduced to simplify manufacturing, then the bump connection is improved, but the sealing resin flows into the through hole polluting the heat dissipation paste
Solution Approach 1:
The insulating layer is designed as a multi-functional structure where the coplanar second portion contains the sealing resin while the first portion protects the heat dissipation paste. This universal design achieves both easy manufacturing with good bump connection and reliable heat dissipation paste protection without requiring a tall dam.
4Reliability
If a separate dam structure is added to contain sealing resin, then the heat dissipation paste is protected, but the processing time and cost increase
Solution Approach 1:
The insulating layer is merged with the substrate structure, eliminating the need for a separate dam structure. The coplanar second portion of the insulating layer contains the sealing resin while the first portion protects the heat dissipation paste, reducing processing steps and time while maintaining reliability.
Solution Approach 2:
The insulating layer serves multiple functions including sealing resin containment and heat dissipation paste protection, eliminating the need for separate dam structures and reducing overall processing time and cost.
5Ease of manufacture
If the insulating layer is made uniform in thickness, then the manufacturing is simplified, but the heat dissipation efficiency is reduced
Solution Approach 1:
The insulating layer is segmented into a first portion with greater thickness that contacts the heat dissipation paste and a second coplanar portion. This segmentation optimizes heat dissipation efficiency by providing adequate thermal contact while maintaining simplified manufacturing through the coplanar design.
Solution Approach 2:
The insulating layer has different thicknesses in different locations: a thicker first portion where heat dissipation is critical and a thinner coplanar second portion for manufacturing simplicity. This local quality variation optimizes both heat dissipation efficiency and ease of manufacture.
Data Source
AI summary
A thin flip chip package structure comprises a substrate, a chip and a heat dissipation paste, wherein the substrate comprises an insulating layer and a trace layer. The insulating layer comprises a first insulating portion and a second insulating portion, the first insulating portion comprises a first upward surface, a first downward surface, a first thickness and a recess formed on the first downward surface, wherein the recess comprises a bottom surface. The second insulating portion comprises a second upward surface, a second downward surface and a second thickness larger than the first thickness. The trace layer is at least formed on the second insulating portion, the chip disposed on top of the substrate is electrically connected with the trace layer and comprises a plurality of bumps, and the heat dissipation paste is disposed at the recess.