PVD Shield Coating for Dielectric Matching and Faster Burn-In
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Solution Overview
Problem
Physical vapor deposition (PVD) chambers face challenges in reducing burn-in time and matching the dielectric constant of the inner shield surfaces to the target material, leading to variations in circuit impedance, plasma distribution, and film thickness uniformity, especially when using expensive target materials like those for ovonic threshold switch layers.
Innovation Solution
Applying an aluminum oxide coating on the inner surfaces of the PVD chamber shields with a dielectric constant similar to the target material to reduce burn-in time and prevent contamination, thereby enhancing deposition uniformity and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner surfaces of the PVD chamber are coated with dielectric material during deposition, then the shield maintains conductivity, but the dielectric constant difference between coating and target causes circuit impedance variation and voltage distribution problems
Solution Approach 1:
The patent applies a coating layer with the same dielectric constant as the target material (both having dielectric constant of approximately 25-30), eliminating the dielectric constant difference that causes impedance variation. This homogeneity in dielectric properties between target and coating resolves the circuit impedance uniformity problem while maintaining shield conductivity.
2Manufacturing precision
If a new PVD chamber undergoes burn-in to reduce dielectric constant difference, then the dielectric constant of coating approaches target material, but the burn-in time requires about 20 kilowatt hours and delays production by weeks
Solution Approach 1:
The patent pre-coats the inner shield surfaces with dielectric material having a dielectric constant substantially similar to the target material before production use. This preliminary action eliminates the need for lengthy burn-in processes, reducing activation time from weeks to minimal duration while achieving proper dielectric constant matching from the start.
Solution Approach 2:
The patent uses a sacrificial coating layer that is intentionally designed to be temporary during burn-in. The coating material is selected to be easily removable or to degrade during the burn-in process, allowing the system to achieve target dielectric constant matching without permanent loss of material or extended time, effectively making the initial coating a disposable element that serves its purpose and then disappears.
3Manufacturing precision
If the target material is used to coat the inside of the shield, then the dielectric constant matches the target, but the high cost of expensive target materials like Ge-As-Se compounds makes this impractical
Solution Approach 1:
The patent uses a inexpensive dielectric coating material applied to the shield inner surfaces that serves as a temporary or sacrificial layer. This cheap coating material replaces the need to use expensive target materials for shield coating, significantly reducing material consumption costs while still achieving the necessary dielectric constant matching during the burn-in process.
Solution Approach 2:
The patent creates a composite structure where an inexpensive dielectric coating material is applied to the shield surfaces. This composite approach combines the low cost of the coating material with the functional requirement of dielectric constant matching, avoiding the need to use expensive target materials like Ge-As-Se compounds for the shield coating application.
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 significantly reduces the burn-in time from 20 kilowatt hours to 2-3 kilowatt hours, allowing for quicker production readiness and minimizing material costs by maintaining the shield's conductivity and reducing particle contamination.
Implementation Method 1
physical vapor deposition (PVD) is a process for depositing a thin film. A PVD process generally includes bombarding a target including a source material with ions from a plasma, causing the source material to be sputtered from the target
Implementation Method 2
A PVD process generally includes bombarding a target including a source material with ions from a plasma, causing the source material to be sputtered from the target
Data Source
AI summary
Methods and apparatus for reducing burn-in time of a physical vapor deposition shield, including: sputtering a dielectric target having a first dielectric constant to form a dielectric layer upon an inner surface of a shield, wherein the shield includes an aluminum oxide coating having a second dielectric constant in an amount sufficient to reduce the burn-in time, and wherein the first dielectric constant and second dielectric constant are substantially similar.