TiW PVD Target Assembly With Roughened Edge for Nodule Control
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Solution Overview
Problem
Nodules form on the sputtering face of titanium-tungsten targets during the sputtering process, leading to peeling and contamination of the deposited film, which reduces the target assembly's lifetime and affects the quality of the semiconductor devices.
Innovation Solution
A target assembly for PVD chambers is designed with a peripheral portion having an angled surface extending radially outward, where an annular portion of the surface has a higher roughness than the remainder, and the average grain size of tungsten powder is adjusted to reduce nodule formation and peeling, using methods like twin wire arc spray or abrasive medium texturizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If material is sputtered from the central portion of the target, then the target produces titanium-tungsten film on the substrate, but nodules form on the outer peripheral edge of the target face causing peeling and particle generation
Solution Approach 1:
The patent applies local quality by creating distinct surface regions with different properties: a smooth central sputtering surface for optimal film deposition and a roughened peripheral region for particle containment. This localized differentiation resolves the contradiction by allowing the central area to maintain high manufacturing precision while the periphery handles the harmful nodule formation, thereby extending target reliability.
2Productivity
If the target operates for extended periods, then production efficiency increases, but nodules accumulate and peel generating particles that contaminate the deposited film
Solution Approach 1:
The patent segments the target surface into functionally distinct zones: a smooth central region for controlled material ejection and a roughened peripheral region for particle trapping. This segmentation allows continuous operation at high productivity while preventing particle contamination of the deposited film, thus maintaining manufacturing precision over extended production periods.
3Productivity
If the target surface is smooth, then sputtering efficiency is maximized, but nodules form and peel at the peripheral edges
Solution Approach 1:
The patent implements local quality by applying different surface characteristics to different regions: the central sputtering surface remains smooth for high efficiency material ejection, while the peripheral region is intentionally roughened to prevent nodule peeling. This resolves the contradiction by localizing the anti-peeling function to where it is most needed, preserving both sputtering efficiency and target durability.
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 texturized surface extends the target and chamber life by reducing peeling, improving the uniformity of the sputtering process and maintaining the quality of the deposited titanium-tungsten film.
Implementation Method 1
During the sputtering process, titanium-tungsten material is sputtered from the surface of the target and deposited onto a substrate disposed opposite the surface of the target
Implementation Method 2
using methods like twin wire arc spray or abrasive medium texturizing
Data Source
AI summary
Target assemblies for PVD chambers are provided herein. In some embodiments, a target assembly for a PVD chamber includes: a backing plate; and a target coupled to the backing plate and having a substrate facing surface opposite the backing plate, wherein a peripheral portion of the target includes an angled surface extending radially outward and toward the backing plate, wherein an annular portion of the angled surface has a surface roughness greater than a surface roughness of a remainder of the substrate facing surface of the target.