Metal Interface Grain Architecture for Reliable Substrate Bonding
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Solution Overview
Problem
Forming reliable connections between substrates in semiconductor devices is challenging due to difficulties in bonding conductive regions across different substrates.
Innovation Solution
The solution involves creating a device with multiple substrates, each with conductive regions composed of grain layers with varying average grain sizes and crystalline orientations. These substrates are bonded using a process that includes depositing insulative regions, forming recesses, and depositing conductive layers, followed by annealing to fuse the conductive layers into a single layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding methods are used to form connections between substrates, then connections can be established, but bonding reliability is poor and process difficulty increases
Solution Approach 1:
The conductive region is segmented into multiple grain layers with different average grain sizes. The first grain layer has a first average grain size and the second grain layer has a second average grain size different from the first. This segmentation allows each layer to contribute different properties to the bonding interface, improving bonding reliability while maintaining manufacturability.
Solution Approach 2:
Different grain layers are assigned different local qualities in terms of grain size and crystalline orientation. The first grain layer may have a first crystalline orientation while the second grain layer has a second crystalline orientation. This local quality variation optimizes the bonding interface properties at different locations within the conductive region, enhancing bonding reliability without excessive process complexity.
2Reliability
If multiple grain layers with different grain sizes are used, then bonding reliability is improved, but device structure becomes more complex
Solution Approach 1:
The conductive region is divided into multiple grain layers with distinct average grain sizes. This segmentation creates a structured approach to improving reliability while keeping each individual layer relatively simple in composition, balancing complexity and performance.
Solution Approach 2:
The invention changes physical parameters of the grain layers, specifically the average grain size and crystalline orientation, to optimize bonding properties. By varying these parameters across different layers rather than changing material composition, the device complexity is controlled while still achieving improved reliability.
3Reliability
If grain layers with different crystalline orientations are used, then bonding effectiveness is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
Different grain layers are assigned different local crystalline orientations to optimize bonding effectiveness. The first grain layer has a first crystalline orientation and the second grain layer has a second crystalline orientation, creating local quality variations that enhance bonding without requiring uniform precision across the entire structure.
Solution Approach 2:
The conductive region is segmented into multiple grain layers, each with specific crystalline orientation characteristics. This segmentation allows the manufacturing process to target orientation control at the layer level rather than requiring precise control of the entire conductive region, effectively managing manufacturing precision requirements.
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
This approach enables effective bonding between substrates, enhancing the reliability of connections and allowing for low-temperature copper-copper bonding, which is independent of grain orientation and suitable for a wide range of substrates.
Implementation Method 1
followed by annealing to fuse the conductive layers into a single layer
Implementation Method 2
bonding conductive regions across different substrates
Implementation Method 3
depositing conductive layers
Data Source
AI summary
A method, system, and devices are disclosed herein involving a first substrate with a first grain layer, a second substrate with a second grain layer, and a third grain layer contacting the first grain layer and the second grain layer. The third grain layer having an average grain size smaller than the first grain layer and second grain layer.