Copper Metallization of Through Silicon Vias via Electrolytic Deposition
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Solution Overview
Problem
Current methods for copper metallization of through silicon via features are limited by low current densities and long filling times, making it difficult to achieve defect-free, rapid filling of large dimension vias in a commercially practicable manner.
Innovation Solution
An electrolytic copper deposition method using a composition comprising copper methane sulfonate, methane sulfonic acid, polarizers, and depolarizers to promote faster copper deposition at the via bottom than at the opening, achieving bottom-up filling and reducing fill time significantly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional electrolytic copper deposition methods using superfilling additives are used, then small size features can be filled at high current densities, but large dimension through silicon via features require extremely long filling times (up to 20 hours)
Solution Approach 1:
The invention changes the chemical parameters of the deposition electrolyte by using copper methane sulfonate instead of conventional copper sulfate, and by incorporating specific organic compounds (polarizers and/or depolarizers) that promote faster copper deposition. These parameter changes enable significantly accelerated copper fill speeds in large dimension TSV features while maintaining bottom-up filling behavior and defect-free results
Solution Approach 2:
The invention introduces organic compounds (polarizers and/or depolarizers) as intermediary substances in the deposition electrolyte. These intermediaries mediate the copper deposition process by promoting faster deposition rates at the via bottom compared to the via opening, thereby enabling rapid bottom-up filling of large TSV features without conventional long plating durations
2Productivity
If high current densities are used to accelerate copper filling, then filling time is reduced, but defect-free filling becomes difficult to achieve
Solution Approach 1:
The invention changes the electrolyte composition parameters to copper methane sulfonate-based chemistry with specific organic additives, which enables the system to tolerate and utilize higher current densities while still achieving defect-free filling. The modified chemical parameters create a more robust deposition environment that maintains filling quality at accelerated rates
Solution Approach 2:
The organic compounds (polarizers and/or depolarizers) act as intermediaries that mediate between high current density input and defect-free filling output. These intermediaries ensure uniform and controlled copper deposition even at elevated current densities, preventing defects while maintaining high productivity
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
The method enables up to five times faster copper fill speed compared to prior art, achieving defect-free, void-free, and seam-free filling of through silicon vias with reduced plating durations, particularly for features with aspect ratios greater than 0.3:1.
Implementation Method 1
supplying electrical current to the electrolytic deposition composition to deposit copper metal onto the bottom and sidewall for bottom-up filling
Implementation Method 2
one or more organic compounds selected from among polarizers and/or depolarizers, which one or more organic compounds promotes faster copper deposition at the via bottom than at the via opening
Data Source
AI summary
A method for metallizing a through silicon via feature in a semiconductor integrated circuit device substrate comprising immersing the semiconductor integrated circuit device substrate into an electrolytic copper deposition composition comprising a source of copper ions, an organic sulfonic acid or inorganic acid, or one or more organic compounds selected from among polarizers and/or depolarizers, and chloride ions.