Titanium Target Grain Control for Sputtering Stability
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Solution Overview
Problem
High-purity titanium targets with a purity of 5N5 (99.9995%) face issues with macro pattern irregularities and increased average crystal grain size, leading to non-uniformity and particle generation during high-rate sputtering, which affects the quality and stability of thin film deposition in electronic devices.
Innovation Solution
A high-purity titanium target with a macro pattern-free surface and average crystal grain size of 10 microns or less is produced through primary and secondary forging at specific temperature ranges, followed by cold rolling and heat treatment, ensuring uniform crystal orientation and preventing fractures and cracks during high-power sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-purity titanium target with purity of 5N5 (99.9995%) is used, then impurity concentration is reduced, but macro pattern irregularities and increased average crystal grain size occur leading to non-uniformity and particle generation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the average crystal grain size to 10 microns or less and eliminating macro pattern irregularities on the target surface. This involves adjusting processing parameters such as rolling reduction rate, heat treatment temperature, and forging conditions to achieve the desired crystal grain structure that prevents particle generation while maintaining high purity
Solution Approach 2:
The patent employs preliminary action by performing multiple preprocessing steps including primary forging, secondary forging, and cold rolling before the actual sputtering process. These preliminary treatments establish a uniform fine crystal grain structure and eliminate macro patterns in advance, preventing particle generation during subsequent high-rate sputtering
2Productivity
If high-rate sputtering is conducted to improve production efficiency, then productivity increases, but target fractures or cracks occur preventing stable sputtering
Solution Approach 1:
The patent applies the principle of curvature by ensuring the target surface is free from macro pattern irregularities and has a uniform fine crystal grain structure. This smooth, uniform surface structure distributes stress evenly during high-rate sputtering, preventing fracture initiation and maintaining target integrity at high power levels
Solution Approach 2:
The patent changes the physical state and structural parameters of the target by controlling the crystal grain size to 10 microns or less and eliminating macro patterns. This structural modification increases the target's resistance to fracture and crack propagation, enabling stable operation during high-rate sputtering processes
3Object-generated harmful factors
If titanium film is used as pasting layer to prevent particle generation, then particle generation is reduced, but adhesive bonding strength is insufficient causing film separation
Solution Approach 1:
The patent applies composite materials by forming a titanium nitride film on the titanium target surface through sputtering in a nitrogen-containing atmosphere. This composite structure combines the particle-preventing properties of titanium with the adhesive strengths of titanium nitride, creating a surface layer that both prevents particle generation and ensures strong bonding
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 effectively reduces impurities and abnormal discharge phenomena, stabilizes sputtering characteristics, and enhances deposition uniformity by eliminating macro pattern irregularities and maintaining a small average crystal grain size, thereby improving the quality of titanium nitride films and reducing particle generation.
Implementation Method 1
This sputtering method is a method of physically colliding positive ions such as Ar+ to a target disposed on a cathode and discharging the metal atoms structuring the target with the collision energy thereof.
Implementation Method 2
a melted and cast ingot is subject to primary forging at a temperature of 800 to 950° C., and subject to secondary forging at a temperature exceeding 500° C. but 600° C. or lower
Data Source
AI summary
A high-purity titanium target for sputtering having a purity of 5N5 (99.9995%) or higher, wherein the high-purity titanium target has no macro pattern on the target surface. An object of this invention is to provide a high-quality titanium target for sputtering, in which impurities causing particles and abnormal discharge phenomena are reduced, and which is free from fractures and cracks even during high-rate sputtering, and capable of stabilizing the sputtering characteristics, effectively inhibiting the generation of particles during deposition, and improving the uniformity of deposition.