Stacked Die Pillar Alignment for Thinner Memory Packages
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to increase storage capacity while reducing the thickness of semiconductor packages, as traditional die attach materials contribute significantly to the overall height, leading to fragility, warping, and reduced production yields.
Innovation Solution
Implementing a semiconductor package with a substrate and stacked IC dies separated by pillar structures that eliminate the need for die attach materials, using tapered or tiered pillars for alignment and electrical coupling, and incorporating mold compounds or wire bond loops for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional die attach materials are used to bond semiconductor dies, then the dies can be securely connected, but the package thickness increases and the risk of die cracking and warping increases
Solution Approach 1:
The patent removes traditional die attach materials (such as epoxy resins and solder) from the semiconductor packaging process. Instead, it uses self-aligning through-holes with protrusions that mechanically interlock with corresponding recesses in adjacent dies, eliminating the need for separate bonding materials and reducing overall package thickness.
Solution Approach 2:
The patent introduces through-holes with protrusions as an intermediary mechanical feature that facilitates die-to-die connection. These protrusions fit into recesses to create a self-aligning, mechanically stable interface without requiring traditional attach materials, thereby reducing thickness while maintaining reliability.
2Ease of manufacture
If traditional die attach materials are used, then dies can be bonded together, but production yields decrease due to warping and cracking
Solution Approach 1:
The patent implements self-aligning through-holes with protrusions that automatically guide and position adjacent dies during assembly. This self-service mechanism eliminates the need for precise external alignment processes and reduces manual intervention, thereby improving production yield while simplifying the manufacturing process.
Solution Approach 2:
The alignment features (protrusions and recesses) are pre-formed in the dies during fabrication. This preliminary action ensures that when dies are stacked, they automatically align without requiring additional alignment steps, reducing manufacturing complexity and improving yield.
3Reliability
If die attach materials are used, then electrical connections can be established, but the package height increases reducing storage capacity density
Solution Approach 1:
The patent merges the mechanical bonding function and the electrical connection function into a single integrated structure. The through-holes with protrusions serve both to mechanically bond adjacent dies and to provide electrical interconnection pathways, eliminating the need for separate bonding materials and reducing package height.
Solution Approach 2:
The through-hole structure performs multiple functions simultaneously: it provides mechanical support, enables self-alignment, facilitates thermal management, and establishes electrical connections. This multi-functionality reduces the overall package height while maintaining all necessary connection reliability.
Data Source
AI summary
Implementations described herein relate to various semiconductor device assemblies. In some implementations, a semiconductor device assembly includes a substrate, a first integrated circuit die over the substrate including a first recess that penetrates into a first edge of the first integrated circuit die, and a second integrated circuit die over the first integrated circuit die including a second recess that penetrates into a second edge of the second integrated circuit die. The semiconductor device assembly includes a pillar structure that uses the first recess and the second recess to align perimeters of the first integrated circuit die and the second integrated circuit die.