HBM Chip Package Interconnect Isolation for Defective Die Removal
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Solution Overview
Problem
Existing high bandwidth memory (HBM) module structures face challenges in efficiently removing defective dies during stacking, which can lead to operational failures and damage to other functional dies due to the complexity of removing interconnect structures connected to defective dies.
Innovation Solution
A chip package structure design that includes a protective layer with first and second filling blocks, allowing for the selective breaking off of interconnect structures connected to defective dies using laser ablation, thereby isolating defective dies without damaging neighboring functional dies, and a fabrication method that involves forming openings in the protective layer to facilitate this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HBM module structures are used without selective interconnect breaking, then manufacturing is simpler, but defective dies cannot be efficiently removed and may damage other functional dies
Solution Approach 1:
The interconnect structure is segmented into multiple parts: the first conductive pad on the defective die, the connection structures, and the second conductive pad on the functional die. By selectively breaking the interconnect at the first conductive pad location, the defective die is isolated while preserving connections to functional dies. This segmentation allows targeted removal capability without requiring complete disassembly of the stacked structure.
Solution Approach 2:
The harmful element (defective die) is extracted from the functional system by breaking its interconnect connections. The method extracts only the necessary connection path to the defective die's first conductive pad, allowing selective isolation without affecting other dies. This extraction principle enables removal of defective components while maintaining system integrity.
2Reliability
If laser ablation is used to break interconnect structures, then selective isolation of defective dies is achieved, but additional fabrication steps are required
Solution Approach 1:
The interconnect structure is designed with a predetermined weak point at the first conductive pad location before stacking. This preliminary configuration allows the interconnect to be easily broken at the desired location using laser ablation or other methods, rather than requiring complex selective breaking after assembly. The structure is prepared in advance to facilitate future selective isolation if needed.
Solution Approach 2:
The mechanical process of selectively breaking interconnect structures is replaced with laser ablation, an optical/thermal process. The laser precisely removes material at the first conductive pad location to break the electrical connection, substituting a non-contact, highly precise thermal field method for mechanical breaking. This reduces the risk of mechanical damage and improves precision.
3Strength
If filling blocks are added to cover broken interconnect structures, then protection and structural integrity are improved, but device complexity increases
Solution Approach 1:
The filling block serves multiple functions simultaneously: it fills the opening created by breaking the interconnect, protects the broken interconnect structure from environmental damage, maintains mechanical integrity of the package, and prevents moisture or contaminants from entering. By merging these multiple functions into a single component, the solution achieves structural reinforcement without proportionally increasing complexity.
Solution Approach 2:
The filling block acts as an intermediary element between the broken interconnect structure and the external environment. It mediates the transition from a broken, exposed interconnect to a protected, sealed structure. The filling block is positioned at the protective layer, serving as a buffer that protects the underlying broken interconnect while maintaining overall package integrity.
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 isolates defective dies, simplifies the removal process, reduces damage to functional dies, and enhances the reliability and efficiency of the chip package structure by ensuring normal operation and reducing fabrication complexity.
Implementation Method 1
breaking off the interconnect structure connected with the defective die via the first opening
Data Source
AI summary
A chip package structure may include a stack structure, routing layer, protective layer and a plurality of first filling blocks. The stack structure may include a plurality of dies stacked. The routing layer may be over a side of the stack structure. A plurality of interconnect structures may be disposed in the routing layer, and any two of the dies in the stack structure may be connected with each other through at least one interconnect structure. The protective layer may be over a side of the routing layer away from the stack structure. One first filling block may be over a side of one interconnect structure away from the stack structure, and the first filling block may extend through the protective layer along a stacking direction.