Remote ICP Radical Deposition for Conformal Low-k Dielectric Films
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Solution Overview
Problem
Current materials and processes for forming low-k dielectric films in integrated circuits suffer from poor mechanical properties, poor step coverage, and damage from plasma-based processes due to charged particle bombardment and high energy UV irradiation.
Innovation Solution
A method involving a remote plasma source generates low-energy plasma radicals in a separate region, which are then introduced through a dual-channel showerhead to form conformal low-k dielectric films with improved step coverage and tunable film composition by reacting with precursor gases, using a radical-based chemical vapor deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma-based processes are used to form dielectric films, then film deposition is achieved, but plasma damage occurs due to charged particle bombardment and high energy UV irradiation
Solution Approach 1:
The plasma source is separated from the substrate processing region, creating a remote plasma region that generates plasma radicals without direct ion bombardment. This segmentation allows the beneficial radical species to reach the substrate while excluding the harmful charged particles and high energy UV photons.
Solution Approach 2:
A showerhead structure acts as an intermediary between the plasma source and substrate. It allows plasma radicals to pass through to the substrate while blocking charged particles and high energy UV irradiation, enabling film deposition without plasma damage.
2Productivity
If conventional CVD processes are used, then film formation is achieved, but step coverage is poor
Solution Approach 1:
The process transitions from conventional CVD to remote plasma-enhanced CVD, changing the chemical reaction parameters by introducing plasma radicals. This enables conformal film deposition with excellent step coverage (>95%) even on high aspect ratio structures (1:1 to 50:1) while maintaining low processing temperatures.
3Speed
If dielectric constant is reduced to achieve faster circuitry, then circuit speed improves, but mechanical properties deteriorate
Solution Approach 1:
The process deposits composite dielectric films with tunable composition, achieving low dielectric constant (k < 3.0) while maintaining excellent mechanical properties. The remote plasma process enables precise control of film stoichiometry and bonding structure, creating a composite material that balances electrical and mechanical performance.
Solution Approach 2:
By controlling plasma power, gas flow rates, and processing temperature, the film composition and dielectric constant are tuned to achieve optimal balance between low-k performance and mechanical strength, eliminating the trade-off between circuit speed and structural integrity.
4Reliability
If post treatment is applied to improve film quality, then film performance improves, but process complexity increases
Solution Approach 1:
The remote plasma process inherently produces high quality films with excellent conformality and controlled composition during deposition, eliminating the need for separate post-treatment steps. The process self-optimizes film properties through plasma parameter control, reducing overall process complexity while maintaining or improving film reliability.
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 achieves dielectric films with at least 95% step coverage and tunable properties, reducing plasma damage and enhancing conformality, while allowing control over film composition and dielectric constant.
Implementation Method 1
generating an inductively coupled plasma in the remote plasma region using the reaction gas to form plasma radicals
Implementation Method 2
exposing the precursor gas in the processing region to plasma radicals to form a dielectric film on the substrate
Data Source
AI summary
A method for processing a substrate is provided. The method includes disposing a substrate in a processing region of a process chamber and flowing a reaction gas into a remote plasma region of the process chamber, flowing a precursor gas into the processing region through the second plurality of channels in the showerhead, generating an inductively coupled plasma in the remote plasma region using the reaction gas to form plasma radicals, and exposing the precursor gas in the processing region to plasma radicals to form a dielectric film on the substrate with at least 95% step coverage.