CTAB Interconnect Coating Against EM Dendrite Shorting
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Solution Overview
Problem
Semiconductor devices are susceptible to electrochemical migration (EM) that leads to the formation of Sn dendrites causing short circuits between interconnect structures, particularly in densely packed devices, reducing reliability.
Innovation Solution
Application of a coating of cetyltrimethylammonium bromide (CTAB) over interconnect structures to inhibit the formation of Sn dendrites by retarding Sn ion deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If semiconductor devices are densely packaged to increase integration density, then the quantity of devices per unit area increases, but the susceptibility to electrochemical migration and dendrite formation increases due to smaller spacing between terminals
Solution Approach 1:
The patent introduces a coating layer comprising cetyltrimethylammonium bromide (CTAB) molecules as an intermediary substance between adjacent interconnect structures. This coating layer physically blocks the migration path of metal ions, preventing electrochemical migration while allowing the interconnect structures to maintain their original design and spacing, thus resolving the contradiction between high integration density and reliability
2Productivity
If terminal spacing is reduced to increase device density, then more devices can be integrated, but moisture accumulation between terminals increases the risk of electrochemical migration
Solution Approach 1:
The CTAB coating layer serves as a protective intermediary that adheres to the surface of interconnect structures, creating a hydrophobic barrier that prevents moisture accumulation in the gaps between closely-spaced terminals. This allows terminals to be placed closer together without increasing susceptibility to electrochemical migration caused by moisture
Solution Approach 2:
The coating layer creates a chemically inert environment around the interconnect structures by forming a hydrophobic barrier that excludes moisture and electrolytes, effectively isolating the metal surfaces from the harmful aqueous environment that enables electrochemical migration, even when terminals are densely packed
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
Prevents the formation of EM dendrites, thereby enhancing the reliability and reducing defects in semiconductor devices by maintaining electrical integrity.
Implementation Method 1
a coating of cetyltrimethylammonium bromide (CTAB) over interconnect structures to inhibit the formation of Sn dendrites by retarding Sn ion deposition
Data Source
AI summary
A semiconductor device has a substrate, an electrical component including a plurality of interconnect structures over a first surface of the substrate, and CTAB coating disposed over the plurality of interconnect structures of the electrical component to reduce formation of dendrites between a first one of the plurality of interconnect structures and a second one of plurality of interconnect structures. The electrical component can be a semiconductor die or discrete device. An encapsulant is deposited over the electrical component and substrate. A bump is formed over a second surface of the substrate opposite the first surface of the substrate. CTAB and de-ionized water are dispensed over the electrical component and substrate. The de-ionized water is dried leaving the CTAB coating over the interconnect structures. The CTAB coating completely covers that portion of the interconnect structure exposed between the electrical component and substrate.