Curved Pad Bonding in Stacked Memory for Misalignment Tolerance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increase in the number of memory cells in a memory device leads to an increase in device size, and the bonding of peripheral circuits and memory cell arrays on different substrates results in contact failures and increased resistance due to reduced bonding surface area and misalignment.
Innovation Solution
A manufacturing method involving different planarization processes to form pads with concave and convex curved surfaces on separate structures, ensuring increased bonding area and reduced misalignment by forming first pads with a concave surface and second pads with a convex surface, enhancing the bonding force between the structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pads are bonded with a flat bonding surface, then the bonding process is simple, but the bonding area is reduced and contact failures occur
Solution Approach 1:
The patent applies curvature to the pad surfaces by forming concave curved surfaces on one pad and convex curved surfaces on the bonding counterpart. This curved surface design increases the effective bonding area and improves contact reliability by distributing the bonding interface over a larger area, thereby reducing contact failures while maintaining reasonable manufacturing complexity through planarization processes.
2Quantity of substance
If the number of memory cells is increased to increase data storage capacity, then the data storage capacity increases, but the device size increases
Solution Approach 1:
The patent transitions from planar pad bonding to three-dimensional curved surface bonding. By forming concave and convex curved surfaces on the pads and bonding them together, the invention utilizes the vertical dimension to increase the bonding area without expanding the lateral footprint, thereby increasing data storage capacity while controlling overall device size.
3Manufacturing precision
If planarization is performed to create flat pad surfaces, then the manufacturing process is simplified, but misalignment occurs and bonding area decreases
Solution Approach 1:
The patent changes the surface geometry parameter from flat to curved by controlling the planarization process to create concave and convex curved surfaces. This parameter change increases the bonding area and improves alignment tolerance, thereby enhancing bonding contact reliability while maintaining manufacturability through controlled planarization techniques.
Data Source
AI summary
A memory device, and a method of manufacturing the memory device, includes a lower structure including a first pad exposed through a top surface of the lower structure. The memory device also includes an upper structure including a second pad exposed through a bottom surface of the upper structure. The first and second pads are bonded to each other, and an interface at which the first and second pads are bonded to each other forms a curved surface.