Semiconductor Package Interface Pits for Underfill Delamination
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Solution Overview
Problem
Delamination issues occur at the interface between underfill materials and encapsulants in semiconductor packages, leading to reliability concerns.
Innovation Solution
The semiconductor package design includes a package substrate, an interposer, and chip structures with specific encapsulants and underfill layers. These layers have surface treatments with pores and pits to enhance adhesion, with the underfill layers filling these features to increase bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional smooth surfaces are used at interfaces between underfill materials and encapsulants, then manufacturing is simple, but adhesion strength is insufficient leading to delamination
Solution Approach 1:
The encapsulant surface is designed with a porous structure consisting of pores and pits. The underfill material penetrates into these pores and pits, creating mechanical interlocking that significantly enhances adhesion strength between the encapsulant and underfill material, preventing delamination issues.
Solution Approach 2:
The porous structure (pores and pits) is pre-formed on the encapsulant surface before the underfill material is applied. This preliminary preparation of the surface structure enables the underfill material to automatically penetrate and bond during the normal packaging process, improving adhesion without adding complex manufacturing steps.
2Reliability
If underfill layers completely fill all pores and pits, then adhesion is maximized, but manufacturing precision requirements increase
Solution Approach 1:
The underfill material is designed to partially fill the pores and pits rather than requiring complete filling. This partial filling approach provides sufficient mechanical interlocking for strong adhesion while reducing the stringency of manufacturing precision requirements, making the process more robust and easier to control.
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
The enhanced adhesion between the encapsulants, underfill layers, and chip structures improves the reliability of the semiconductor package by preventing cracking and breaking due to mechanical stress.
Implementation Method 1
at least a portion of the first underfill layer fills one or more of the first pores
Implementation Method 2
at least a portion of the second encapsulant fills one or more of the first pores and the pit
Data Source
AI summary
A semiconductor package includes a base chip, at least one semiconductor chip disposed on the base chip, bump structures disposed between the base chip and the at least one semiconductor chip, an underfill layer surrounding the bump structures, the underfill layer having first pits in a surface thereof, and a first encapsulant in contact with a side surface of the at least one semiconductor chip and the surface of the underfill layer, on the base chip. At least some first pits, among the first pits, are connected to each other to form a first pit tunnel leading inwardly from the surface. At least a portion of the first encapsulant fills the first pit tunnel.