Elongated Copper Pillars for Self-Alignment in Semiconductor Packaging
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Solution Overview
Problem
Misalignment issues during the packaging of semiconductor devices can lead to die gap non-uniformity and electrical connection failures, resulting in yield losses in packaged products.
Innovation Solution
The use of elongated copper pillars arranged in a centripetal orientation on semiconductor devices, which self-align during the solder reflow process, ensuring precise attachment to traces on BOT packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional circular solder bumps are used for attaching dies to BOT packages, then the packaging process is simple, but misalignment occurs between bumps and traces causing die gap non-uniformity and connection failures
Solution Approach 1:
The patent transforms the conventional circular bump shape into an elongated asymmetric shape. This elongated bump structure provides directional guidance during the attachment process, enabling the bump to self-align with the trace on the BOT package. The asymmetric geometry creates a preferred orientation that eliminates misalignment issues while maintaining manufacturing simplicity through standard solder bump formation processes.
2Manufacturing precision
If elongated copper pillars with centripetal orientation are used, then self-alignment and manufacturing precision improve, but the device structure becomes more complex
Solution Approach 1:
The patent employs asymmetric elongated copper pillars arranged in a centripetal pattern radiating from the center of the die. This asymmetric configuration provides inherent alignment cues that guide the die to the correct position on the BOT package during the attachment process, achieving self-alignment without requiring complex external alignment mechanisms.
Solution Approach 2:
The copper pillars are pre-formed with elongated shapes and centripetal orientation before the attachment process. This preliminary structuring creates built-in alignment features that automatically guide the die positioning, eliminating the need for complex real-time alignment procedures and reducing the overall system complexity despite the intricate pillar arrangement.
3Productivity
If misalignment is allowed during packaging, then the packaging process is faster and simpler, but yield losses increase due to electrical connection failures
Solution Approach 1:
The elongated bump structure performs the alignment function automatically during the attachment process without requiring external alignment systems or complex positioning mechanisms. The asymmetric geometry of the bumps self-corrects positional deviations, enabling fast packaging processes while maintaining high connection reliability through inherent self-alignment capabilities.
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 and die gap uniformity, leading to higher yields and improved packaging efficiency by facilitating self-alignment of copper pillars with traces on the BOT package.
Implementation Method 1
which self-align during the solder reflow process
Implementation Method 2
self-align during the solder reflow process
Data Source
AI summary
Semiconductor devices and methods of manufacturing and packaging thereof are disclosed. In one embodiment, a semiconductor device includes an integrated circuit and a plurality of copper pillars coupled to a surface of the integrated circuit. The plurality of copper pillars has an elongated shape. At least 50% of the plurality of copper pillars is arranged in a substantially centripetal orientation.