High-Pressure ALD Gap Fill Using Inhibition Plasma for Seam-Free Films
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Solution Overview
Problem
Existing semiconductor device fabrication processes face challenges in depositing high-quality dielectric films, particularly in filling gaps where voids and seams can form due to the difficulty in achieving uniform deposition.
Innovation Solution
The method involves using a plasma enhanced atomic layer deposition (ALD) process with an inhibition plasma to inhibit deposition on the top portion of the gap, allowing for a bottom-up fill of dielectric material, thereby reducing void formation and seam effects. This is achieved by maintaining a high pressure of at least 8 Torr during the inhibition and deposition phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma enhanced ALD process is used to deposit dielectric material in gaps, then deposition can be achieved, but voids and seams form in the films due to non-uniform deposition
Solution Approach 1:
The patent applies local quality by using an inhibition plasma to selectively prevent deposition at the top portion of the gap while allowing deposition at the bottom. This creates a spatially varying deposition profile where the bottom-up fill mechanism ensures uniform film quality without voids or seams, directly resolving the contradiction between achieving deposition and maintaining film reliability.
2Manufacturing precision
If chamber pressure is reduced during inhibition plasma to prevent contamination, then film quality improves, but process time increases due to pressure cycling
Solution Approach 1:
The patent merges the inhibition plasma step and the ALD deposition step into a single high-pressure process environment. By maintaining constant high pressure (at least 8 Torr) throughout both the inhibition and deposition phases, the process eliminates pressure cycling while achieving both contamination prevention and high deposition rates, thereby improving productivity without sacrificing film quality.
3Manufacturing precision
If inhibition plasma is used to prevent deposition on top portion, then bottom-up fill is achieved, but process complexity increases
Solution Approach 1:
The patent uses parameter changes by adjusting plasma power levels to create the inhibition effect. By controlling the plasma power during the ALD cycle, the process selectively inhibits deposition at the top portion of the gap while maintaining deposition at the bottom, achieving bottom-up fill without requiring additional process steps or complex equipment modifications.
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 enables void-free bottom gap fill with improved film quality, increasing throughput and deposition rate by allowing the ALD process and inhibition plasma to be performed at the same high pressure, thus reducing the time spent changing chamber pressure.
Implementation Method 1
performing a first set of one or more cycles of: exposing the substrate to a plasma including an inhibition gas to inhibit deposition on a portion of the gap; and after (a), depositing dielectric material in the gap
Implementation Method 2
exposing the substrate to a plasma including an inhibition gas to inhibit deposition on a portion of the gap
Implementation Method 3
wherein a pressure of the process chamber is at least 8 Torr during (a) and (b)
Data Source
AI summary
Methods of filling a gap with a dielectric material including using an inhibition plasma during deposition. The inhibition plasma increases a nucleation barrier of the deposited film. The inhibition plasma selectively interacts near the top of the feature, inhibiting deposition at the top of the feature compared to the bottom of the feature, enhancing bottom-up fill. A process chamber may have multiple pressure switches to enable a process after deposition at a higher pressure than the pressure during deposition.