Copper Interconnect Oxygen Removal Using Segmented Plasma
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of copper oxide films during the chemical mechanical polishing (CMP) process in semiconductor device fabrication leads to degraded adhesion of copper interconnections, increased resistance, and reduced reliability due to the removal of carbon from low-k insulating layers during plasma processing, which can cause current leakage and shorten device lifetime.
Innovation Solution
A method involving the use of hydrogen-containing and ammonia-containing plasmas to selectively remove oxygen from copper interconnections, with thin SiN, SiC, or SiCN barrier layers to convert copper oxide to copper, minimizing damage to insulating layers and maintaining their thickness, thereby improving adhesion and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plasma process is performed for a long time to completely remove copper oxide film, then the copper oxide film is completely removed, but the thickness of damaged insulating layer increases
Solution Approach 1:
The plasma treatment is segmented into two separate processes with different durations and parameters. The first process targets copper oxide removal with optimized time to prevent excessive insulating layer damage, while the second process addresses remaining oxide with minimal additional damage
Solution Approach 2:
The first plasma treatment applies partial action by removing most but not necessarily all copper oxide, allowing the second treatment to complete the removal with reduced risk of over-treatment and excessive damage accumulation
2Length of stationary object
If the plasma process is performed weakly to reduce damaged insulating layer thickness, then the damaged insulating layer thickness is reduced, but copper oxide layer is not completely removed
Solution Approach 1:
The removal process is segmented into multiple passes with increasing intensity. The first pass uses weak plasma to minimize damage, while subsequent passes gradually increase intensity to complete oxide removal without causing excessive cumulative damage
Solution Approach 2:
The plasma treatment is applied periodically in multiple cycles rather than continuously. Each cycle allows for controlled removal with intervals that prevent thermal buildup and excessive damage accumulation, achieving complete oxide removal through repeated gentle treatment
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
This approach effectively removes copper oxide films while minimizing the thickness of damaged insulating layers, reducing current leakage and enhancing the reliability of semiconductor devices by maintaining the integrity of the low-k material.
Implementation Method 1
exposed to a plasma that removes oxygen from an upper surface of the metal interconnection
Implementation Method 2
the plasma is a hydrogen-containing plasma that penetrates the barrier layer and converts oxygen on the upper surface of the metal interconnection to water
Implementation Method 3
carbon components of an insulating layer may be removed by the plasma, and thus the carbon content of the insulating layer may be reduced
Data Source
AI summary
Methods of forming devices include forming a first electrically insulating layer having a metal interconnection therein, on a substrate and then forming a first electrically insulating barrier layer on an upper surface of the metal interconnection and on the first electrically insulating layer. The first electrically insulating barrier layer is exposed to a plasma that penetrates the first electrically insulating barrier and removes oxygen from an upper surface of the metal interconnection. The barrier layer may have a thickness in a range from about 5Å to about 50 Å and the plasma may be a hydrogen-containing plasma that converts oxygen on the upper surface of the metal interconnection to water.