Plasma Sputtering Bias Power Control for Recess Filling
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Solution Overview
Problem
In semiconductor manufacturing, plasma sputtering techniques struggle to uniformly deposit metal films on the sidewalls of recesses with high aspect ratios, leading to incomplete filling and voids during copper plating due to poor directionality of metal ions and excessive sputter etching.
Innovation Solution
A plasma sputtering method and equipment that control bias power to balance metal film deposition with sputter etching, ensuring simultaneous metal ion attraction and plasma-generated etching, allowing uniform deposition on sidewalls and preventing overhangs and voids by optimizing bias power levels and process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bias power is increased to improve metal film deposition rate, then deposition efficiency is improved, but sputter etching increases causing removal of deposited films
Solution Approach 1:
The patent applies parameter changes by optimizing the bias power to a specific level that balances metal ion attraction for deposition while controlling sputter etching. This parameter optimization resolves the contradiction by finding the optimal operating point where deposition rate is sufficiently high without excessive etching that would remove the deposited film.
2Object-generated harmful factors
If bias power is kept low to prevent sputter etching, then film removal is prevented, but metal ions lack directionality causing poor sidewall deposition
Solution Approach 1:
The patent resolves this contradiction by optimizing the bias power parameter to achieve the right balance: low enough to prevent excessive sputter etching that would remove deposited film, but high enough to provide sufficient directionality to metal ions for uniform sidewall deposition in high aspect ratio recesses.
3Device complexity
If conventional plasma sputtering is used to deposit metal film, then deposition process is simple, but incomplete filling of recesses occurs due to poor ion directionality
Solution Approach 1:
The patent resolves this contradiction by optimizing deposition parameters (bias power, process conditions) rather than changing the fundamental deposition process. This maintains relative simplicity of the plasma sputtering process while achieving complete recess filling through careful parameter control that enhances metal ion directionality and sidewall deposition uniformity.
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 uniform metal film deposition on sidewalls, ensuring complete filling of recesses with copper without voids, improving film thickness uniformity and reducing the risk of overhangs and damage to underlying layers.
Implementation Method 1
generating metal ions by way of making a metal target sputter with a plasma generated from a discharge gas
Implementation Method 2
applying to the mounting table a bias power to cause a metal film deposition based on a metal ion attraction
Implementation Method 3
a sputter etching based on the plasma generated from the discharge gas
Data Source
AI summary
The present invention relates to a technology for depositing a thin metal film by using a plasma sputtering technique on a top surface of a target object, e.g., a semiconductor wafer or the like, and on a surface of a recess opened at the top surface. The film deposition method is characterized in that a film deposition process to deposit a metal film on a sidewall of the recess by generating metal ions by way of making a metal target sputter with a plasma generated from a discharge gas in the processing container and by applying to the mounting table a bias power to cause a metal film deposition based on a metal ion attraction and a sputter etching based on the plasma generated from the discharge gas simultaneously on the top surface of the target object.