Copper Wiring Cobalt Capping Electromigration
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Solution Overview
Problem
Conventional copper wiring techniques in semiconductor devices lead to decreased electromigration characteristics due to reduced wiring line width, affecting the desired electrical characteristics of high-speed and high-integration semiconductor devices.
Innovation Solution
A method involving the formation of a copper-based conductive layer within a groove on a semiconductor substrate, followed by a cobalt-based capping layer using electroless plating, and subsequent cleansing with basic and acidic solutions to improve electrical characteristics, including the use of chemical mechanical polishing (CMP) and specific cleansing solutions like ethanolamine and oxalic acid to enhance the copper wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional copper wiring techniques are applied with reduced wiring line width, then high integration degree is achieved, but electromigration characteristics deteriorate
Solution Approach 1:
The patent applies composite materials by combining copper with other metals (such as cobalt, nickel, or tungsten) to form a copper-based composite conductive layer. This composite structure maintains the high conductivity of copper while adding the strength and electromigration resistance of the other metals, thereby achieving both high integration and reliable electromigration characteristics in reduced wiring line width applications
Solution Approach 2:
The patent changes the material parameters of the conductive layer by transitioning from pure copper to copper-based composite materials with modified compositional parameters. This parameter change allows the wiring to maintain adequate electromigration resistance even at reduced line widths required for high integration degree semiconductor devices
2Speed
If copper wiring with reduced line width is used for high speed devices, then device speed is improved, but electromigration characteristics decrease
Solution Approach 1:
The patent uses copper-based composite materials that combine the high electrical conductivity of copper (enabling high device speed) with the enhanced electromigration resistance provided by additional metal elements. This composite approach allows reduced line width for high speed performance while maintaining adequate electromigration characteristics through the synergistic material composition
3Reliability
If electroless plating is used to deposit cobalt-based capping layer, then copper surface is protected, but plating uniformity may be affected by surface condition
Solution Approach 1:
The patent applies preliminary action by performing surface preparation and treatment of the copper-based conductive layer before depositing the cobalt-based capping layer through electroless plating. This preliminary surface conditioning ensures uniform nucleation and growth of the capping layer, achieving both protective functionality and manufacturing precision in terms of layer uniformity
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 improves electromigration characteristics and reduces leakage current, resulting in higher breakdown voltages and enhanced reliability and performance of semiconductor devices.
Implementation Method 1
depositing a cobalt-based capping layer on the copper-based conductive layer by electroless plating
Implementation Method 2
removing a portion of the preliminary copper-based conductive layer by a chemical mechanical polishing (CMP) method
Data Source
AI summary
Provided are methods of manufacturing semiconductor devices. The methods may include forming a first insulation layer on a semiconductor substrate, forming a groove by selectively etching the first insulation layer, filling the groove with a copper-based conductive layer, depositing a cobalt-based capping layer on the copper-based conductive layer by electroless plating, and cleansing the first insulation layer and the cobalt-based capping layer using a basic cleansing solution.