Self-Aligned Interlocking Bonded Structure for 3D Memory Alignment
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Solution Overview
Problem
Misalignment of copper bonding pads on opposing substrates during the bonding process leads to decreased product yield in semiconductor devices, as existing technologies lack effective self-alignment mechanisms.
Innovation Solution
The implementation of self-aligned interlocking bonded structures using matching pairs of protrusions and recesses, where a first substrate with mesa structures is aligned within recess cavities on a second substrate, allowing for the formation of metal connection pads through selective growth of a third metallic material, thereby ensuring precise alignment and electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional copper bonding pads are used on opposing substrates, then the bonding process can be performed, but misalignment occurs leading to decreased product yield
Solution Approach 1:
The patent employs asymmetric interlocking structures where protrusions on one substrate precisely match recesses on the opposing substrate. This asymmetric geometry provides self-alignment during bonding, eliminating misalignment issues and improving both manufacturing precision and product yield compared to traditional symmetric copper bonding pads
Solution Approach 2:
The patent implements nested interlocking features where protrusions fit into recesses, creating a hierarchical alignment system. The mesa structures with embedded metal pads are nested within recess cavities, providing multiple levels of geometric constraint that ensure precise alignment and prevent misalignment during the bonding process
2Manufacturing precision
If self-aligned interlocking bonded structures with mesa structures are implemented, then alignment accuracy is enhanced, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the mesa structures with embedded metal pad structures and recess cavities on each substrate before the bonding process. These pre-configured interlocking features automatically guide alignment during bonding, achieving high precision without requiring complex real-time alignment mechanisms
Solution Approach 2:
The interlocking mesa and recess structures serve as self-aligning features that automatically position the substrates correctly during bonding without external intervention. The geometric complementarity of protrusions and recesses creates inherent self-service alignment, reducing the need for complex alignment equipment and procedures
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 enhances alignment accuracy and yield by enabling self-aligned bonding, facilitating the formation of reliable metal connection pads that provide both mechanical and electrical connections between substrates, thus improving the efficiency of semiconductor device manufacturing.
Implementation Method 1
forming a metal connection pad by selectively growing a third metallic material from the first metal pad structure and the second metal pad structure
Data Source
AI summary
A first substrate has a first mesa structure that protrudes from a first bonding-side planar surface. A first metal pad structure is embedded within the first mesa structure. A second substrate has a first recess cavity that is recessed from a second bonding-side planar surface. A second metal pad structure is located at a recessed region of the first recess cavity. The first bonding-side planar surface and the second bonding-side planar surface are brought into physical contact with each other, while the first mesa structure is disposed within a volume of the first recess cavity by self-alignment. A gap is provided between the first metal pad structure and the second metal pad structure within a volume of the first recess cavity. A metal connection pad is formed by selectively growing a third metallic material from the first metal pad structure and the second metal pad structure.