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Beijing Yingsitao Technology Co., Ltd
Core Technology Unveiled: Analysis of the Working Principle and Unique Design Features of Ion Sputtering Instrument
Date: 2025-10-18Read: 2
Ion sputtering apparatusIt is a core equipment for preparing high-purity and high bonding metal/compound thin films, which achieves atomic level deposition through ion bombardment of target materials and is widely used in the fields of semiconductor chips, optical devices, and nanomaterials. Understanding its working principle and design characteristics is the key to optimizing the performance of thin films.
1、 Working principle:
The core of ion sputtering is "momentum transfer". The equipment generates plasma (containing a large amount of Ar ⁺ ions) through gas discharge (usually argon gas, purity>99.999%). Under the action of a high-voltage electric field (usually -300V to -1000V), Ar ⁺ ions accelerate and bombard the surface of target materials (such as titanium metal and oxide ceramics). Ions undergo elastic collisions with target atoms, transferring kinetic energy to the target atoms (a single Ar ⁺ ion can transfer energy of about 10-100 eV). When the energy obtained by the target atoms exceeds their binding energy with surrounding atoms (usually 5-20 eV), they will be sputtered from the surface of the target. The sputtered atoms are accelerated by the plasma region and deposited onto the surface of substrates (such as silicon wafers and glass) at a certain energy (usually 1-10 eV), forming a dense and uniform thin film.
For magnetic target materials such as iron and cobalt, magnetron sputtering technology is required - permanent magnets are arranged on the back of the target material (forming a closed magnetic field) to confine the plasma close to the surface of the target material (increasing the plasma density by 10-100 times), thereby reducing the sputtering voltage (from 1000V to 300-500V), reducing substrate thermal damage, and increasing the deposition rate (up to several micrometers per hour).
2、 Unique design features:
1. Target material and magnetic field coupling design: The magnet layout of the magnetron sputtering instrument (such as ring magnets or complementary magnetic poles) directly affects the plasma distribution. For example, the magnetic field strength of balanced magnetron sputtering is about 0.01-0.1T on the surface of the target material, which concentrates the plasma in the central area of the target material and ensures sputtering uniformity (deviation<± 5%); Unbalanced magnetron sputtering enhances the edge magnetic field of the target material, directing the plasma towards the substrate and improving the adhesion between the film and the substrate (adhesion>10N/cm).
2. Multi target co sputtering system: To prepare compound thin films (such as TiN, ITO), the equipment is equipped with multiple target materials (such as titanium target+nitrogen, indium target+tin target+oxygen). By independently controlling the sputtering power of each target material (accuracy ± 1W), the composition of the thin film can be accurately adjusted (such as the ratio of In ₂ O3 to SnO ₂ in ITO is 9:1, and the resistivity can be reduced to 10 ⁻Ω· cm).
3. Vacuum and gas control module: Using a molecular pump (maximum vacuum degree<10 ⁻⁶ Pa) and a mass flow controller (MFC, flow accuracy ± 0.5sccm), the partial pressure (usually 0.1-10Pa) and ratio (such as oxygen argon ratio 1:9 to 3:7) of the working gas (such as argon and oxygen) are precisely adjusted to control the chemical stoichiometry and microstructure of the film (such as the crystal structure of the alumina film changing from the gamma phase to the alpha phase).
4. Substrate heating and bias system: The substrate heating stage (temperature range: room temperature -800 ℃) can regulate the crystallinity of thin films (such as amorphous silicon thin films that transform into polycrystals after annealing at 500 ℃, increasing carrier mobility by 10 times); The substrate bias voltage (-50V to -500V) accelerates ion bombardment through an electric field, enhances the density of the film (porosity<1%), and improves the step coverage ability (for complex microstructure surface deposition).
Ion sputtering apparatusThrough the scientific mechanism of "ion bombardment atomic release directed deposition" and precise engineering design, thin film preparation from laboratory small samples to industrial scale large-sized substrates has been achieved, which is a key tool for modern material surface engineering.