Semiconductor Device Surface Modification for Bonding Reliability
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Solution Overview
Problem
Semiconductor devices face reliability and load cycling capability issues due to bond wire lift-off and heel cracks during temperature cycling, particularly with aluminum wires used in power electronics.
Innovation Solution
A method involving the formation of an insulating material layer on a semiconductor substrate, modifying its surface by ion irradiation or trench formation to increase adhesion, and creating a conductive structure for improved bonding, which enhances the load cycling capability and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum wires are used for bonding semiconductor chips in power electronics, then the bonding process is simple and cost-effective, but the load cycling capability and reliability deteriorate due to bond wire lift-off and heel cracks during temperature cycling
Solution Approach 1:
A copper wire is introduced as an intermediary bonding material between the semiconductor chip metallization and the external circuit. The copper wire exhibits superior mechanical stability and resistance to lift-off and heel cracks compared to aluminum wires, while still enabling effective electrical and mechanical connection. This intermediary material resolves the contradiction by providing both reliability and resistance to harmful failure modes.
Solution Approach 2:
The material parameter of the bond wire is changed from aluminum to copper, which fundamentally alters the mechanical and thermal properties of the bonding system. Copper's higher ductility, strength, and resistance to fatigue enable the system to withstand temperature cycling loads without experiencing lift-off or heel cracks, thereby improving load cycling capability while eliminating the harmful failure modes associated with aluminum wires.
2Strength
If the surface of the insulating material layer is modified by ion irradiation or trench formation, then the adhesion between the insulating layer and conductive structure improves, but the manufacturing complexity and process steps increase
Solution Approach 1:
The surface of the insulating material layer is modified in advance, before the conductive structure is formed, through ion irradiation or trench formation. This preliminary action creates a pre-treated surface with enhanced adhesion properties, ensuring strong bonding between the insulating layer and the subsequently deposited conductive structure. By performing the surface modification beforehand, the process integrates smoothly into the existing manufacturing flow without requiring complex post-processing steps.
Solution Approach 2:
The physical and chemical parameters of the insulating material layer surface are changed through ion irradiation or trench formation. These parameter changes include increased surface roughness, altered surface energy, and creation of anchoring structures, all of which significantly enhance the adhesion strength between the insulating layer and the conductive structure. The modified surface parameters enable stronger bonding without requiring additional adhesive materials or complex multi-layer structures.
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 modified surface adhesion increases the reliability and load cycling capability of semiconductor devices, achieving equivalent bond yields to aluminum wires while using copper wires, which are mechanically more stable.
Implementation Method 1
modifying at least a portion of a surface of the insulating material layer after forming the insulating material layer
Data Source
AI summary
A method for forming a semiconductor device includes forming an insulating material layer above a semiconductor substrate and modifying at least a portion of a surface of the insulating material layer after forming the insulating material layer. Further, the method includes forming an electrical conductive structure on at least the portion of the surface of the insulating material layer after modifying at least the portion of the surface of the insulating material layer.