PVD Through-Via Deposition Using a Bottom Sacrificial Plate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Physical vapor deposition (PVD) processes face challenges in achieving uniform film deposition on substrates with high aspect ratio features, such as through-vias, due to the non-conformal coating caused by the target being located above the substrate, leading to poor thickness uniformity and coverage on the via walls.
Innovation Solution
A PVD chamber design incorporating a sacrificial plate positioned below the substrate, which is rotated and biased to provide additional sputtered material from below, combined with a gas inlet system to deliver process gas through apertures between the sacrificial plate and the substrate, enhancing film deposition uniformity by mimicking the target material's deposition from both top and bottom directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional PVD target is positioned above the substrate, then the sputtering process can be performed, but non-uniform film deposition occurs on high aspect ratio features such as through-vias
Solution Approach 1:
The patent introduces a sacrificial plate positioned below the substrate, creating a dual-directional sputtering configuration. Material is deposited from both the top (conventional target) and bottom (sacrificial plate) simultaneously, transforming the single-direction deposition into a three-dimensional conformal coating process that uniformly coats high aspect ratio through-vias
Solution Approach 2:
Instead of only depositing material from above the substrate, the patent inverts the deposition approach by placing a sacrificial plate below the substrate that also sputters material upward. This bidirectional approach ensures material reaches all surfaces of vertical via walls, solving the coverage problem inherent in conventional top-down sputtering
2Productivity
If the target is located above the substrate in a conventional PVD chamber, then the sputtering process can proceed, but poor thickness uniformity is achieved on via walls
Solution Approach 1:
The patent adds a vertical dimension to the deposition process by positioning a sacrificial plate below the substrate. This creates simultaneous top-down and bottom-up material flux, transforming the deposition geometry to achieve uniform thickness on vertical via walls while maintaining high deposition rates from both sources
3Quantity of substance
If process gas is delivered only from the chamber atmosphere, then the sputtering process can occur, but insufficient material ejection and deposition control is achieved
Solution Approach 1:
The patent segments the gas delivery system by providing separate gas inlet pathways: one for the chamber atmosphere and another specifically for the region between the sacrificial plate and substrate. This segmented gas supply enables independent optimization of plasma conditions for top and bottom sputtering sources, improving deposition control and material utilization
Solution Approach 2:
The patent introduces an intermediary gas delivery system that provides process gas directly to the region between the sacrificial plate and substrate. This intermediary gas supply acts as a mediator to enhance plasma generation and material ejection from the bottom surface, improving overall deposition control and 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 improves film deposition uniformity on substrates with high aspect ratio features by ensuring consistent material coverage on the via walls, addressing the issue of non-uniformity and enhancing the thickness and adhesion of the deposited layer.
Implementation Method 1
The argon ions are accelerated towards the target due to the negative bias and collide with a surface of the target causing atoms of the target material to be ejected therefrom
Implementation Method 2
During processing, a high voltage is applied to the target to generate a plasma and enable the sputtering process. Because the voltage source is negatively biased, the target may also be referred to as the 'cathode.' The high voltage generates an electric field inside the PVD chamber that is used to enable sputtering of the target material and generate and emit electrons from the target
Implementation Method 3
The magnet array applies an external magnetic field that traps electrons and confines the plasma close to the target
Implementation Method 4
The trapped electrons can then collide with and ionize the gas atoms disposed within the processing region of the PVD chamber. The collision between the trapped electron(s) and gas atoms will cause the gas atoms to emit electrons that are used to sustain and further increase the plasma density within the processing region of the PVD chamber
Implementation Method 5
The ejected atoms of target material then travel towards the substrate and chamber shielding to incorporate into the growing thin film thereon
Data Source
AI summary
A physical vapor deposition (PVD) chamber deposits thin films on substrates having through-vias (TVs) formed therethrough in an electronic device fabrication process. More particularly, apparatus and methods improve film deposition uniformity when the TVs have a high aspect ratio or are otherwise shaped in a manner that can decrease the deposition of sputtered material. A sacrificial plate is used below the substrate in a manner whereby material is sputtered into the TVs from below in addition to the conventional top-down sputtering.