Integral Chip Stack Packaging for Yield and Quality Control
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Solution Overview
Problem
Existing semiconductor packages face challenges in achieving smaller sizes, lighter weights, high performance, high capacity, and high reliability, particularly in the fabrication of chip stack structures with semiconductor chips.
Innovation Solution
A semiconductor package design featuring a chip stack module with an integral structure, where multiple memory chips are uniformly stacked and tested independently before being integrated with a base chip, using a bonding layer and sealant to enhance reliability and flexibility in fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If chip stack structures are fabricated with multiple semiconductor chips stacked to reduce package size and increase capacity, then the density and capacity of the semiconductor package are improved, but the fabrication complexity and difficulty of ensuring uniform quality across all chips increase
Solution Approach 1:
The fabrication process is segmented into two independent stages: (1) fabricating chip stack modules with multiple memory chips stacked and bonded together, and (2) mounting these pre-fabricated modules onto the base chip substrate. This segmentation allows each stage to be optimized independently, reducing overall fabrication complexity while maintaining high capacity.
Solution Approach 2:
Chip stack modules are preliminarily fabricated, bonded, and tested independently before being mounted on the base chip substrate. This preliminary action ensures uniform quality across all memory chips in the stack before final integration, making the overall fabrication process more manageable and less complex.
2Volume of moving object
If multiple memory chips are stacked in a chip stack module with integral structure, then the package size is reduced and capacity increased, but the difficulty of detecting and measuring quality uniformity across all chips increases
Solution Approach 1:
The chip stack module is treated as an independent, uniformly structured unit containing multiple memory chips. By segmenting the overall package into identical modular units, quality detection is simplified to verifying module-level uniformity rather than individually examining each chip within the stack.
Solution Approach 2:
Quality uniformity is detected and measured during the preliminary fabrication of chip stack modules, before final integration. This preliminary detection ensures that all memory chips within a stack meet uniform quality standards, making subsequent assembly easier and more reliable.
3Reliability
If chip stack modules are fabricated independently and then mounted on base chip substrate, then the yield is improved and process quality is clarified, but the number of fabrication steps increases
Solution Approach 1:
The fabrication process is divided into independent segments: chip stack module fabrication, base chip substrate preparation, and final assembly. This segmentation improves yield by isolating defects to specific segments, allowing targeted rework without scrapping entire batches, thus justifying the increased number of steps.
Solution Approach 2:
Chip stack modules are preliminarily fabricated and tested independently to establish clear process quality metrics. This preliminary action clarifies where defects occur in the fabrication process, enabling targeted process improvement and higher overall yield despite additional fabrication steps.
4Length of stationary object
If bonding layer protrusions are minimized for optimal package design, then the package height and size are reduced, but the difficulty of manufacture increases due to tighter tolerances
Solution Approach 1:
The bonding layer protrusion height is predetermined and controlled during the preliminary chip stack module fabrication stage. By establishing precise bonding parameters in advance, the protrusion height is optimized to minimize package dimensions while maintaining manufacturability through controlled tolerances.
Solution Approach 2:
The bonding layer protrusion parameter is optimized to a specific height range that balances package miniaturization with manufacturing ease. This parameter change allows the bonding layer to be thin enough to reduce package height but thick enough to maintain robust bonding and facilitate assembly.
Data Source
AI summary
A semiconductor package may include a base chip, at least one chip stack module on the base chip, and a sealant on the base chip and sealing the at least one chip stack module. The at least one chip stack module may have an integral structure, in which a plurality of memory chips may be stacked and uniform. Each chip stack module of the at least one chip stack module may be on the base chip while having the integral structure.