Low-k Material Layer Particle Reduction via PECVD Delay Gas
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Solution Overview
Problem
Low-k material layers formed in PECVD chambers face issues with particle formation and fluorine residue, leading to degraded interface properties and increased particle counts, which affect manufacturing efficiency and product yield.
Innovation Solution
The method involves using a reaction gas, cleaning gas, high-frequency, and low-frequency power during deposition, with the source of the reaction gas turned off and low-frequency power reduced or turned off after reaching a predetermined thickness, and continuing the cleaning gas during a delay time to reduce particle formation and fluorine concentration, while also diverting residual gases from the chamber pipelines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the source of reaction gas is turned off after low-k material layer reaches predetermined thickness, then deposition process should be complete, but remaining reaction gas continues deposition forming particles on the layer
Solution Approach 1:
The patent applies preliminary anti-action by reducing low-frequency power and high-frequency power before the deposition process completely ends. This preemptive reduction in plasma power prevents the excessive energy that would otherwise cause remaining reaction gas to continue depositing and form particles on the completed low-k material layer.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting the plasma power parameters during the deposition process. Specifically, the low-frequency power is reduced to a value lower than during normal deposition, and high-frequency power is reduced or turned off during a delay period after the reaction gas source is closed, adapting the energy input to the actual deposition state to prevent particle formation.
2Reliability
If fluorine-containing etching gas is used to clean oxides on chamber wall, then cleaning effectiveness is improved, but fluorine residue remains in pipelines and diffuses into low-k material layer degrading interface properties
Solution Approach 1:
The patent applies preliminary action by introducing a cleaning gas (such as nitrogen or oxygen) into the chamber and pipelines before the low-k material layer deposition begins. This preliminary gas introduction flushes out and removes fluorine residue from the pipelines, preventing it from diffusing into the low-k material layer and degrading the interface properties.
Solution Approach 2:
The patent uses a cleaning gas as an intermediary substance to address the fluorine residue problem. The cleaning gas acts as a mediator that displaces and removes the harmful fluorine residue from the pipelines through gas flow, preventing direct contact and diffusion of fluorine into the low-k material layer while maintaining system cleanliness.
3Object-generated harmful factors
If reduced low-frequency power and reduced high-frequency power are supplied during delay time, then particle number decreases, but deposition completion time increases
Solution Approach 1:
The patent applies partial action by selectively reducing only the low-frequency power and high-frequency power during the delay period after deposition, while maintaining other deposition parameters. This partial adjustment is sufficient to prevent particle formation without requiring complete process shutdown, thus minimizing the time extension while achieving the particle reduction goal.
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 reduces particle counts and fluorine concentration in low-k material layers, improving film quality and yield, preventing peeling and copper diffusion, and ensuring stable interface properties.
Implementation Method 1
a fluorine-containing etching gas is usually introduced to generate plasma and remove the oxides on the chamber wall
Implementation Method 2
remove the oxides on the chamber wall
Implementation Method 3
many low-k materials are formed through plasma-enhanced chemical vapor disposition (PECVD)
Implementation Method 4
low-k materials are formed through plasma-enhanced chemical vapor disposition (PECVD)
Implementation Method 5
the fluorine residue of the etching gas remaining in the pipelines connecting with the chamber easily diffuse into the low-k material layer
Data Source
AI summary
A method of reducing the number of particles on a low-k material layer is described. The low-k material layer is formed by a plasma enhanced chemical vapor deposition process, wherein a reaction gas, a cleaning gas, a high-frequency power and a low-frequency power are used. The method includes turning off the reaction gas and the low-frequency power after the low-k material layer is formed, and continuing to provide the cleaning gas during a delay time.