Titanium Interlayer Mitigates Aluminum Extrusion in Power Devices
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Solution Overview
Problem
Current technologies fail to produce whisker-free thick aluminum films for power semiconductor devices, leading to manufacturing inefficiencies and reliability concerns due to lateral extrusion defects in metal contact layers.
Innovation Solution
A semiconductor device structure incorporating a substrate layer, epitaxial layer, dielectric layer, and alternating layers of aluminum and titanium interlayers, with the titanium interlayers mitigating lateral extrusion growth, allowing for thick aluminum layers up to 7 microns without significant conductivity loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the thickness of the aluminum layer is increased to 7 microns for power management devices, then the high power handling capability is achieved, but lateral extrusion defects including whiskers and hillocks significantly increase
Solution Approach 1:
A titanium interlayer is introduced between the aluminum contact layer and the underlying structure. This intermediary layer prevents direct interaction between aluminum and the substrate, thereby suppressing lateral extrusion and whisker formation while allowing the aluminum layer to maintain its thick configuration for high power handling.
Solution Approach 2:
The patent creates a composite structure consisting of aluminum and titanium layers. The aluminum layer provides high power handling capability, while the titanium interlayer provides structural stability and prevents defect formation. This composite approach combines the advantages of both materials to resolve the contradiction.
2Power
If the thickness of the aluminum layer is increased to 7 microns, then the high power handling capability is achieved, but manufacturing throughput decreases due to low yield
Solution Approach 1:
The titanium interlayer acts as a mediator that enables the aluminum layer to be deposited at thicker configurations without causing manufacturing defects. This allows standard deposition processes to produce high-yield thick aluminum films, maintaining manufacturing throughput while achieving high power handling capability.
3Power
If the thickness of the aluminum layer is increased, then the high power handling capability is achieved, but lateral extrusion defects increase leading to device performance deterioration
Solution Approach 1:
The titanium interlayer serves as a mediator that constrains the aluminum layer, preventing lateral extrusion and maintaining film uniformity. This allows thick aluminum films to be manufactured with consistent quality and precision, eliminating the trade-off between thickness and uniformity.
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 solution effectively reduces lateral extrusion defects, maintaining high manufacturing throughput and device reliability by controlling the thickness of titanium interlayers between 10 angstroms and 500 angstroms, ensuring mechanical support and conductivity.
Implementation Method 1
A first titanium interlayer is deposited onto the first aluminum layer
Data Source
AI summary
A semiconductor device comprising a substrate layer, an epitaxial layer, a dielectric layer, a first aluminum layer, a first titanium interlayer and a second aluminum layer. The first titanium interlayer is disposed between the first aluminum layer and the second aluminum layer. A process for fabricating a semiconductor device comprising the steps of: preparing a semiconductor wafer; depositing a first aluminum layer onto the semiconductor wafer; depositing a first titanium interlayer onto the first aluminum layer; depositing a second aluminum layer onto the first titanium interlayer; applying an etching process so that a plurality of trenches are formed so as to expose a plurality of top surfaces of a dielectric layer; and applying a singulation process so as to form a plurality of separated semiconductor devices.