Nanograined Copper Electroplating via Polyether Polyol Additives
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Solution Overview
Problem
There is a need for a commercially viable method to produce nanograined copper under typical manufacturing process conditions, as existing methods fail to achieve this without significant changes in subsequent processing steps.
Innovation Solution
A method of electroplating nanograined copper involves using an electroplating bath containing a copper salt, acid, chloride compound, accelerator, leveler, and suppressor, specifically a polyether polyol compound, to form nanograined copper at room temperature with an average grain size of about 100 nm and resistivity of 1.78-1.90 μOhm·cm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating methods are used, then copper films can be deposited, but the grain size is too large and recrystallization occurs at room temperature
Solution Approach 1:
The patent changes the chemical parameters of the electroplating bath by introducing specific additives (polyether polyol suppressor, accelerator, and leveler) to control the deposition process. These parameter changes result in nanograined copper with grain sizes of 10-100 nm that remain stable at room temperature without recrystallization.
Solution Approach 2:
The patent uses intermediary substances (additives in the electroplating bath) to mediate the deposition process. The suppressor, accelerator, and leveler act as intermediaries that control grain growth and stabilize the nanograined structure, preventing direct recrystallization of the copper deposits.
2Manufacturing precision
If high conductivity copper is required, then IACS high conductivity copper is used, but nanograined structure cannot be achieved with conventional methods
Solution Approach 1:
The patent modifies the electroplating bath composition by adding specific chemicals (polyether polyol suppressor, accelerator, leveler) to achieve nanograined copper deposition under typical manufacturing conditions, maintaining ease of manufacture while achieving precise grain size control.
Solution Approach 2:
The electroplating bath formulation achieves multiple functions simultaneously: it deposits copper with nanograined structure, maintains low resistivity (1.78-1.90 μOhm·cm), and ensures stability under typical manufacturing conditions, all within a single conventional electroplating process.
3Temperature
If copper plating is performed for hybrid bonding, then bonding temperature should be as low as possible, but grain growth control is difficult
Solution Approach 1:
The patent performs preliminary action by creating a stable nanograined copper structure during electroplating that is resistant to grain growth. This pre-established nanograined structure remains stable at low bonding temperatures (100-250°C), enabling hybrid bonding without significant grain growth.
Solution Approach 2:
The patent changes the deposition parameters through specific additives to create a nanograined structure with high thermal stability. The polyether polyol suppressor and other additives modify the deposition kinetics to produce grains that remain stable at bonding temperatures, enabling low-temperature hybrid bonding.
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 effectively produces nanograined copper with consistent grain size and resistivity across various annealing conditions, from room temperature to elevated temperatures, maintaining the desired properties.
Implementation Method 1
electroplating the substrate in the electroplating bath to form the nanograined copper
Implementation Method 2
electroplating the substrate in the electroplating bath to form the nanograined copper
Implementation Method 3
annealing the nanograined copper at room temperature for 1-7 days
Data Source
AI summary
A method of electroplating nanograined copper on a substrate includes: providing the substrate; providing an electroplating bath that includes a copper salt, an acid, a leveler, a chlorine compound, an accelerator, a suppressor; and water; and electroplating the substrate in the electroplating bath to form the nanograined copper at room temperature. The suppressor is a ployether polyol compound, the nanograined copper has an average grain size of about 100 nm, and the nanograined copper has a resistivity of about 1.78-1.90 μOhm·cm. A nanograined copper prepared according to the method is also disclosed.