Halogen Removal from Low-k Films via High-Pressure Heating
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Solution Overview
Problem
Existing semiconductor device manufacturing processes face challenges in effectively removing halogens like fluorine from films without degrading the film, especially when fluorine penetrates into low dielectric constant (Low-k) films and metal wiring, as conventional methods like ashing and plasma treatments can damage the film and are not efficient for deep-seated halogen removal.
Innovation Solution
A method involving a heating treatment at pressures higher than 1 atm and temperatures higher than 100 degrees C, with an organic solvent in a liquid phase exhibiting polarity, is used to contact the halogen-containing film, facilitating the diffusion and removal of fluorine without chemical reactions for Low-k films and using oxidation-reduction reactions for Cu films, thereby reducing halogen content while minimizing film deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma etching using fluorine-containing gas is performed on Low-k film, then etching is achieved, but fluorine penetrates into the film and degrades reliability
Solution Approach 1:
The process is divided into two distinct stages: first plasma etching to achieve pattern formation, then a separate heating treatment stage to remove fluorine. This segmentation allows each process to be optimized independently - etching efficiency in the first stage and fluorine removal in the second stage without compromising either function.
Solution Approach 2:
The fluorine that penetrates into the Low-k film during etching is converted from a harmful contaminant into a removable substance through the heating treatment. By heating the film to 100-200°C in an inert atmosphere, the fluorine is activated and can be effectively removed, transforming the harmful effect into a manageable removal target.
2Reliability
If conventional heating treatment is performed to remove fluorine, then fluorine removal is achieved, but Low-k film deteriorates
Solution Approach 1:
The heating treatment parameters are precisely controlled - temperature range of 100-200°C, pressure of 1-100 Pa, and treatment time of 1-60 minutes. These parameter changes create optimal conditions for fluorine removal while maintaining Low-k film integrity, avoiding the degradation that occurs with conventional heating methods.
Solution Approach 2:
The heating treatment is performed in an inert atmosphere (nitrogen or rare gas) at low pressure (1-100 Pa). This inert environment prevents oxidation and chemical reactions that would degrade the Low-k film, while still allowing fluorine to be activated and removed through thermal energy.
3Reliability
If ashing treatment is used to remove fluorine-containing material, then surface fluorine is removed, but fluorine that penetrates into film cannot be removed
Solution Approach 1:
The conventional chemical ashing process is replaced with a thermal heating treatment. Instead of using reactive chemicals to remove fluorine, thermal energy is applied to activate and remove fluorine atoms that have penetrated into the film. This mechanical/thermal substitution enables deep fluorine removal that chemical methods cannot achieve.
4Reliability
If plasma treatment is used to remove residual fluorine, then fluorine removal is achieved, but film is deteriorated
Solution Approach 1:
The heating treatment is conducted in an inert atmosphere of nitrogen or rare gas at low pressure (1-100 Pa). This inert environment protects the Low-k film from oxidation and plasma-induced damage while still enabling fluorine removal through thermal activation, avoiding the film deterioration caused by plasma 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 method effectively reduces halogen content within the films without degrading the Low-k films or causing oxidation of Cu, maintaining the film's integrity and improving the semiconductor device's reliability by efficiently removing fluorine and potentially other halogens.
Implementation Method 1
performing a heating treatment on a halogen-containing film at a pressure higher than 1 atm and a temperature higher than 100 degrees C. in order to suppress a deterioration of the halogen-containing film while keeping an organic solvent, which is in a liquid phase and exhibits a polarity, in contact with a surface of the halogen-containing film
Implementation Method 2
performing a heating treatment on a halogen-containing film at a pressure higher than 1 atm and a temperature higher than 100 degrees C.
Implementation Method 3
performing a heating treatment on a halogen-containing film at a pressure higher than 1 atm
Data Source
AI summary
A method of removing a halogen includes performing a heating treatment on a halogen-containing film at a pressure higher than 1 atm and a temperature higher than 100 degrees C. in order to suppress a deterioration of the halogen-containing film while keeping an organic solvent, which is in a liquid phase and exhibits a polarity, in contact with a surface of the halogen-containing film.