Embedded Packaging Structure With Sintered Laser-Stop Layer
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Solution Overview
Problem
The high power laser used in laser drilling for forming blind holes in embedded packaging structures can damage the metal layer of semiconductor dies, necessitating the use of a barrier layer to prevent such damage, which existing methods may not adequately address.
Innovation Solution
The implementation of a sintered metal layer bonded to the metallic bonding layer of the semiconductor die, acting as a barrier layer during laser drilling, and optionally combined with a copper foil, to protect the die and enhance electrical and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high power laser is used for laser drilling to form blind holes, then the laser drilling efficiency is improved, but the metal layer of the semiconductor die may be damaged
Solution Approach 1:
A sintered metal layer is introduced as an intermediary barrier between the high power laser and the semiconductor die. This sintered metal layer absorbs the laser energy and prevents direct damage to the metal contact points and main body of the die, while still allowing the laser to effectively drill blind holes through the dielectric material.
Solution Approach 2:
The sintered metal layer is formed on the semiconductor die before the laser drilling process. This preliminary action prepares the die surface with a protective layer that can withstand the subsequent high power laser exposure, enabling the laser drilling to proceed without damaging the underlying metal structures.
2Object-affected harmful factors
If a barrier layer is formed above the metal layer to protect during laser drilling, then the metal layer is protected from laser damage, but the electrical conductivity may be affected
Solution Approach 1:
The sintered metal layer is designed with specific material parameters including high electrical conductivity and high melting point. By carefully selecting and controlling these parameters, the barrier layer provides adequate laser protection while maintaining acceptable electrical conductivity for the packaging structure.
Solution Approach 2:
The packaging structure employs a composite material system consisting of the sintered metal layer combined with the dielectric material and metal contact points. This composite structure leverages the complementary properties of each material to achieve both laser resistance and electrical conductivity in the overall system.
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 sintered metal layer effectively prevents laser-induced damage to the semiconductor die while maintaining high conductivity, improving bonding strength and reliability of the packaging structure.
Implementation Method 1
A high power laser source used in the laser drilling process may strike a metal layer serving as the contact point of the semiconductor die or even a main body of the die. Therefore, the fabrication of embedded packaging structure includes a step of forming a barrier layer (or called stop layer) for laser drilling above the metal layer.
Implementation Method 2
The conductive via is provided in a blind hole of the encapsulation layer, and the conductive via is electrically connected with the metallic bonding layer through the sintered metal layer.
Implementation Method 3
The sintered metal layer is bonded to the metallic bonding layer... The sintered metal layer effectively prevents laser-induced damage to the semiconductor die while maintaining high conductivity
Data Source
AI summary
An embedded packaging structure includes a die, a sintered metal layer, an encapsulation layer and a conductive via. The die includes a metallic bonding layer. Sintered metal layer is bonded to the metallic bonding layer. The encapsulation layer covers the die. The conductive via is provided in a blind hole of the encapsulation layer, and the conductive via is electrically connected with the metallic bonding layer through the sintered metal layer.