Plasma Collimation for Uniform Trench and Via Deposition
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Solution Overview
Problem
In semiconductor manufacturing, achieving uniform material deposition and etching in high aspect ratio structures like trenches and via is challenging due to broad angular distribution of deposition atoms or ions, leading to pinching off of entrances and void formation, with existing technologies struggling to control deposition directionality and reduce re-sputtering and re-deposition.
Innovation Solution
A plasma source with a closed-loop magnetic field and a collimation apparatus that blocks off-axis deposition, focuses ions, and tilts their direction, combined with methods to control self-bias voltage and reduce substrate sputtering, to enhance plasma density and uniformity, and prevent material accumulation at the entrance of trenches and via.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deposition sources are made larger than the substrate to achieve deposition uniformity, then broader angular distribution of deposition atoms is obtained, but material accumulates at upper portion of sidewalls and pinches off the upper entrance of trenches and via
Solution Approach 1:
The patent extracts and removes the harmful broad angular distribution component from the deposition process. By using a collimator to block off-angle deposition atoms, only the desired narrow-angle atoms reach the substrate, eliminating the pinching-off problem while maintaining deposition uniformity through controlled directional deposition.
Solution Approach 2:
The collimator serves as an intermediary device between the deposition source and substrate. It selectively transmits atoms within a specific angular range while blocking others, acting as a mediator that resolves the contradiction between achieving uniform deposition and preventing material accumulation at trench entrances.
2Manufacturing precision
If 100% ionization of deposition atoms is achieved to form parallel ion beam, then directionality is improved, but complex plasma control and low pressure operation are required
Solution Approach 1:
The patent changes the pressure parameter to maintain low pressure operation, which reduces gas scattering and preserves ion beam directionality. This parameter change enables the formation of parallel ion beams without requiring overly complex plasma control systems, as the low pressure environment naturally supports directional ion transport.
3Manufacturing precision
If lower pressure is used to maintain ion directionality, then deposition into trenches and via is increased, but plasma density decreases and requires higher power
Solution Approach 1:
The patent applies preliminary ionization of atoms before they enter the low-pressure deposition region. By pre-ionizing the deposition material and using a collimator to select directional ions, the system ensures sufficient plasma density at the source while maintaining ion directionality during transport through the lower pressure region, avoiding the need for excessively high power.
4Loss of substance
If re-sputtering of materials near substrate surfaces is reduced, then material loss is minimized, but control of deposition profile becomes more difficult
Solution Approach 1:
The patent replaces mechanical/physical sputtering processes with a more controlled deposition mechanism. By using a collimator to restrict deposition angles and control ion arrival directions, the system minimizes re-sputtering events while maintaining precise deposition profile control through angular selection rather than relying solely on process parameter adjustments.
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 solution improves deposition and etching uniformity, reduces void formation, and maintains directionality of ions to the substrate, enhancing filling of trenches and via while minimizing re-sputtering and re-deposition, thus addressing the challenges of pinching and material accumulation.
Implementation Method 1
a three-dimensional closed-loop magnetron source with an electrode surrounded by magnets that produce a magnetic field that forms closed-loop lines of flux
Implementation Method 2
The atoms or ions to be deposited must have strong directionality when they reach the wafer surfaces during deposition
Implementation Method 3
Various ways of ionizing atoms and accelerating these ions to substrates can produce variable degrees of directionality
Implementation Method 4
The collimation apparatus can block deposition in broad angles, accelerate ions and focus ions, tilt the direction of the accelerated ions
Implementation Method 5
Material depositions such as sputtering, chemical vapor deposition (CVD), and plasma enhanced CVD (PECVD) are widely used in semiconductor manufacturing
Data Source
AI summary
A plasma deposition apparatus includes a first plasma source that can produce a first plasma confined in a magnetic field, which includes: a gas distribution device configured to supply a gas, a closed-loop electrode defining a center region therein and a central axis through the central region and one or more magnets that are outside an inner surface of the closed-loop electrode. The one or more magnets can produce the magnetic field in the center region. The closed-loop electrode and the one or more magnets can produce the first plasma of activated atoms, molecules, electrons, and ions from the gas. A collimator can collimate the activated atoms, molecules, electrons, and ions produced by the first plasma source and direct the ions to a substrate.