High-Pressure Inhibitor Plasma for Void-Free Dielectric Gap Fill
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Solution Overview
Problem
Existing semiconductor fabrication processes face challenges in depositing high-quality dielectric films in gaps, particularly in features with high aspect ratios, due to issues like void formation and seam creation.
Innovation Solution
The method involves using an inhibitor plasma at high pressure to inhibit deposition on a portion of the gap during atomic layer deposition (ALD), creating a passivated surface and increasing the nucleation barrier to achieve void-free bottom gapfill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma enhanced atomic layer deposition (PEALD) is used to deposit dielectric material in gaps, then deposition can occur, but voids and seams form in the films due to incomplete filling in high aspect ratio features
Solution Approach 1:
The method applies preliminary anti-action by using an inhibitor plasma treatment before dielectric deposition to prevent unwanted deposition at the top of high aspect ratio features. This pre-treatment creates a passivated surface that repels subsequent dielectric material, ensuring that deposition occurs only in the bottom portion of the gap, thereby preventing void formation and achieving complete filling.
Solution Approach 2:
The inhibitor plasma treatment creates local quality differences by selectively passivating only the top portion of the gap while leaving the bottom portion active for deposition. This spatially differentiated surface property enables controlled bottom-up filling, where the dielectric material deposits only where needed (at the bottom) and is prevented from depositing where it would cause defects (at the top).
2Productivity
If deposition is performed in high aspect ratio gaps without inhibition, then material can be deposited, but the deposition profile becomes non-uniform with seams and voids
Solution Approach 1:
The inhibitor plasma treatment is applied as a preliminary action before the main dielectric deposition process. This pre-treatment modifies the surface properties of the gap walls, creating a gradient of reactivity from top to bottom. The preliminary action ensures that when the dielectric precursor is introduced, it only reacts at the bottom of the gap where the surface remains active, producing a uniform bottom-up fill profile.
Solution Approach 2:
The method changes the surface energy parameter of the gap walls through inhibitor plasma treatment. By altering the chemical composition and surface energy of the gap walls (making them less reactive to the dielectric precursor), the process controls where deposition occurs. This parameter change creates a reactive gradient that directs deposition to the bottom of the gap while preventing it at the top, achieving uniform filling.
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 enhances the button-up fill and prevents void formation by selectively inhibiting deposition at the top of the feature, resulting in a more favorable sloped profile and improved film quality.
Implementation Method 1
exposing the substrate to a plasma including a first gas to inhibit deposition on a portion of the gap
Implementation Method 2
creating a passivated surface and increasing the nucleation barrier
Implementation Method 3
depositing dielectric material in the gap includes an atomic layer deposition (ALD) process
Data Source
AI summary
Methods of filling a gap with a dielectric material including using an inhibitor plasma during deposition. When the inhibitor plasma interacts with material in the feature, the material at the bottom of the feature receives less plasma treatment than material located closer to a top portion of the feature or in field. Deposition at the top of the feature is then selectively inhibited and deposition in lower portions of the feature proceeds with less inhibition or without being inhibited. As a result, bottom-up fill is enhanced, which can create a sloped profile that mitigates the seam effect and prevents void formation. In some embodiments, the inhibitor plasma is used at a higher pressure to increase the rate of inhibition, improving throughput.