Monolithic Conductive Column Assembly for Underfill-Free Die Stacking
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Solution Overview
Problem
Conventional semiconductor die assemblies face issues with conductive columns being under- or overfilled, leading to ineffective bonding between dies due to concave recesses or convex protrusions, which can result in poor electrical connections and die separation, exacerbated by stress from cooling or solidification processes.
Innovation Solution
The implementation of monolithic conductive columns that extend through multiple semiconductor dies, eliminating the need for additional conductive material between dies by forming a single elongated piece of conductive material in a single manufacturing step, thereby ensuring effective electrical communication and distributing stress evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive columns are used in semiconductor dies, then electrical interconnection between dies is achieved, but underfill or overfill occurs leading to concave recesses or convex protrusions that cause ineffective bonding and die separation
Solution Approach 1:
The patent merges multiple separate conductive column formations into a single monolithic conductive column that extends continuously through multiple dies. This is achieved by forming one continuous conductive structure that spans across die interfaces, eliminating the need for separate fill operations at each die interface and ensuring uniform stress distribution throughout the entire conductive path.
Solution Approach 2:
The patent segments the monolithic conductive column into multiple portions, each extending through a different die, while maintaining electrical continuity. This segmentation allows the single conductive structure to serve multiple functional roles across different semiconductor dies without requiring separate fill operations, thereby improving both reliability and manufacturing precision.
2Volume of moving object
If bond line thickness is reduced to decrease assembly volume, then device compactness is improved, but bonding reliability deteriorates due to underfill or overfill issues
Solution Approach 1:
The patent combines multiple thin bond lines into a single continuous monolithic conductive column that spans across multiple dies. This merging approach maintains compact assembly volume while ensuring reliable electrical connection throughout the entire stack, as the single continuous structure distributes stress uniformly and eliminates localized fill defects.
Solution Approach 2:
The patent changes the physical parameters of the conductive structure by forming a single continuous column with controlled dimensions that extend through multiple dies. This parameter change from separate short columns to a single elongated column improves bonding reliability while maintaining reduced assembly volume, as the continuous structure provides better stress distribution and electrical connectivity.
3Ease of manufacture
If conventional separate conductive columns are formed in each die, then manufacturing flexibility is maintained, but process complexity increases and material usage increases
Solution Approach 1:
The patent merges the formation of multiple separate conductive columns into a single monolithic conductive column formation process. This is achieved by performing one continuous fill operation that creates a unified conductive structure spanning multiple dies, thereby reducing process complexity and material usage while maintaining manufacturing flexibility through the ability to form the single column with appropriate dimensions and properties.
Data Source
AI summary
A semiconductor device having monolithic conductive columns, and associated systems and methods, are disclosed herein. The semiconductor device can include a semiconductor substrate, a conductive pad, an opening, a non-conductive liner, and a plug of non-conductive material. The conductive pad may be at a surface of the semiconductor substrate. The opening may extend through the semiconductor substrate from the conductive pad to a second surface and define a side wall. The liner may coat the side wall and the plug may fill the opening. A second opening may be formed through the semiconductor device and the opening and a conductive material plated therein.