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The dc magnetron sputtering system (MSS) is widely used in the microelectronic industries for thin film depositions. With certain designs, users have observed low operational performance and high target material consumption rates due to unsatisfactory interactions between electrons or ions and fields inside the sputter. This paper describes refinem...
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... . 1 shows the basic structure of a dc MSS. The physical di- mensions of the system studied are given in Table I. The voltage applied onto the cathode is 400 V with the anode grounded. The pressure inside the vacuum chamber is kept at a base value of . The plasma gas is Ar [11]. Electric and magnetic fields in the magnetron are produced to ...
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Citations
... In their work, C.T. Liu et al. proposed a method to enhance the magnetic field distribution and electron trajectories inside magnetron sputtering. This method resulted in improved target utilization, sputtering efficiency, and substrate deposition rate [7,8]. In a separate study [9], Liu et al. analyzed the impact of magnetic and electric fields on the uniform deposition of target atoms. ...
Magnetron sputtering systems are widely used for depositing industrially important coatings. Research has been conducted to optimize and improve these structures to increase coating effectiveness and target utilization. The paper investigates the engineering problem of uneven target etching caused by an uneven magnetic field in magnetron sputtering equipment. The characteristics of the desired magnetic field distribution required by magnetron sputtering equipment are analyzed, and a corresponding excitation structure and analytical model for cylindrical magnetron sputtering equipment are proposed and calculated. The uniform magnetic field design is realized by analytical modeling of the excitation structure. The axial magnetic field distributions produced by an axisymmetric solenoid system and several similar excitation structures are analyzed and compared. The analytical results were verified through finite element simulations and experiments, demonstrating the accuracy and effectiveness of the method. The excitation structure, which is designed with a uniform magnetic field, can produce an axial component of magnetic flux density with a uniformity deviation of less than 4.3% across 73% of the target surface. The analytical model describes the distribution of the axial component of the magnetic flux density and optimizes the magnetic field. The model enables the simulation of plasma distribution and film growth, aiming to enhance the target utilization rate and substrate deposition rate. The conclusions serve as a reference for designing high-performance magnetron sputtering equipment.
... Compared to conventional magnetron sputtering (CMS) methods, a sputtering target and substrate surface in the FTS system generate a sputtering plasma in the space between two sputtering targets. Neutral working gas and high-energy radical ion particles that originated in the plasma were confined between two targets and move along with the magnetic field [9][10][11]. Therefore, the substrate surface can be directly bombarded by secondary electrons, Ar atoms, and negative ions that obtain high kinetic energy at a cathode sheath Two types of permanent magnetic arrangements were inserted into two cathodes, as shown Figure 1. ...
Conventional sputtering method uses a single cathode with a permanent magnet. Facing targets sputtering (FTS) methods consists of two cathodes. Because of a unique structure, FTS can prepare high quality films with low temperature and low plasma damage. During the film sputtering process, density and confinement of discharged plasma depend on the arrangement of a permanent magnet in the cathode. In this study, we designed two types of permanent magnet arrangements in the FTS system and the designed permanent magnet was inserted into two cathodes in the FTS system. The system was operated in different permanent magnet conditions, and their discharge voltage and properties of as-grown films were recorded. In the designed FTS, compared to a conventional magnetron sputtering method, the substrate temperature increased to a value under 80 °C, which is relatively low, even though the films’ sputtering process was completed.
... Hence the electron trajectories in the vicinity of the target surface can be adjusted [1] and consequently the substrate deposition rates can be controlled [2], [3]. Though the target utilization issues were discussed in [4], the detailed designs only support those dc MS with cylindrical structures [5]. Simple and feasible designs that can better utilize various targets at different dc MS structures with controllable erosion patterns are thus desired. ...
... Those electrons inside the chamber can be modeled by density, electric field intensity, and electron speed in the corresponding Cartesian direction. As indicated in [5], the trajectory of a single electron will be confined at the zero -directional magnetic flux density locations. For a copper target material, Fig. 2 shows the calculated magnetic flux density distributions of the dc MS, and Fig. 3 depicts the confined electron trajectories from (1). ...
... By considering the field symmetries and construction simplicity, the target erosion patterns on most of the commercialized dc MS resemble the racetrack contours. The attached refinements for sputtering rate increment as proposed in [3] and [5] will be adopted for initial investigations. Since both of the attached iron annulus shapes and the target material properties will have diverse impacts on the field distributions, the confined electron trajectories on top of the target will be greatly affected. ...
With proper adjustments of the magnetic fields inside an existing dc magnetron sputter (MS), trajectories of those argon electrons in the vacuum chamber can be further confined and the racetrack erosion patterns on the target surface can be better controlled. Hence the target can be more effectively utilized and the system sputtering rate can also be enhanced. By implementing appropriate passive iron annulus and active compensation magnetizations onto the dc MS, based on Taguchi’s method, three typical reference target erosion patterns are selected for verification. From the promising emulation results, it can be demonstrated that these target erosion patterns can be precisely controlled to the designated profiles and more electron trajectories can be confined, hence the objectives of designing structural refinements for better the dc MS performance can be confirmed.
... W ITH THE DC magnetron sputter (MS) being widely applied as one of the major equipments for depositing thin films in microelectronics related industries [1], [2], better performance and lower cost are the common operational requisites. As a result, appropriate indices that can be applied to justify the target sputtering rate, target erosion profile, and substrate deposition uniformity are desired before any possible system refinement is adopted [3], [4]. In addition, to supply rational performance comparisons among various refinement designs onto the DC MS, adequate numerical schemes that can properly emulate the related sputtering, collision, and deposition processes are also expected. ...
... Based on the general structural refinement guidance that have been developed for target sputtering rate and erosion profile con- trols [4], [8], as illustrated in Fig. 4, the related refinements are adding one iron annulus below the cathode plate, one compensation PM set on the iron base, and two DC coils surrounding the inner and outer PMs. By attaching these components and adjusting the coil currents, the magnetic field distributions above the target surface can be controlled. ...
To smooth the substrate depositions of DC magnetron sputter (MS), such that the supplementary electrical and mechanical adjustment efforts can be alleviated, a refinement scheme that can be applied directly to the existing DC MS will be introduced. By properly control the magnetic and electric fields inside the vacuum chamber, trajectories of those atoms that are sputtered from the target surface can be more spread out. In addition, with the resultant higher plasma density, chance of collisions among the sputtered atoms and those Ar ions in the plasma will also be increased, hence the resulting distributions of target atoms deposited on the substrate surface will certainly be even out. To further confirm such concepts, a rational emulating process that can exploring both the atom sputtering process from the target and those collisions at the chamber with different three-dimensional magnetic and electric field environments is also developed. Thus the associated performance investigations on the DC MS with different magnetron arrangements can then be conveniently explored.
... The magnetostatic configuration generated by the permanent magnets inside the cathodes is a key aspect of this technique. The development of an equivalent model is an important starting point in order to analyze the configuration in different conditions (Ido and Hirose, 2001;Desideri et al., 2005): for instance, the prediction of the magnetic field pattern, modifying the magnetic configuration, by either adding further DC magnetic sources (Liu et al., 2009) or using magnetic materials as targets. Unfortunately, in general, there is no detailed information of the magnetic characteristics of the permanent magnets inside the cathodes, and the inspection of the geometry cannot be simple, as for the case of encapsulated solution. ...
Purpose
– The aim of the work was to obtain an auxiliary instrument able to give the magnetic configuration of a magnetron sputtering device for operation with targets, magnetic and non magnetic, with different heights, starting from a device with no detailed information of the source.
Design/methodology/approach
– An inverse problem has been dealt with. A 2D numerical analysis has been performed, which utilizes as a starting point a model identified with a simple analytical procedure based on measurements.
Findings
– A satisfactory equivalent model has been identified, and validated in several different conditions.
Originality/value
– The proposed approach can be applied when no detailed information of the source is available, in the case of a cathode without a ferromagnetic yoke.
... However, based on the DC MSS structures, the confined electron trajectories that can provide consistent collisions to ionize the plasma and consequently erode the target surfaces will be different. As the adjustable magnetization schemes [4] can only support those DC MSS with symmetrical round target surfaces, simple and feasible designs that can better utilize various targets with controllable erosion patterns are thus desired. ...
... In addition to the eroded dimensions, further improvement can be achieved by properly control the eroded profiles on the target [9]. By adopting the similar schemes as proposed in [4] and [5], Fig. 3 depicts the designed system refinements. It can be seen that the iron annulus and those compensation permanent magnets and coils are all to supply additional adjustments to the system operational magnetic and electric fields. ...
To supply higher deposition rate and better target utilization, simple and cost-effective adjustments that can be applied to the existing DC magnetron sputtering systems are desired. By attaching adequate iron annulus and compensation magnetizations, electron trajectories near the target surface can be confined and the target erosion patterns can then be properly controlled. Hence, the target can be more effectively utilized and the substrate deposition rate can also be indirectly enhanced. Three typical patterns have been selected and promising results have showed that the erosion patterns on the targets can be precisely controlled to the designated reference profiles with resemblances higher than 98.78%, along with the substrate sputtering rate enhancements in the range of 20.87%-23.06%. From such verifications, clearly the refinement concepts for better the system performance can be confirmed.
... By adequate addition of some simple parts based on Taguchi's method, encouraging preliminary performance enhancement on an existing DC MSS can be achieved by more than 30% and the target can also be better utilized [11]. To further confirm the applicability of such concepts, based on similar structural refinement designs, explorations on the DC MSS with different magnetron arrangements and electron distributions are desired. ...
... Based on the optimal refinement design of a DC MSS with single cylindrical magnetron, without additional current excitation, an encouraging pilot investigation showed that the deposition rate can be enhanced by as much as 33.21% [11]. To better demonstrate the advantages of this improved scheme, quantitative analyses on this system at different operational specifications are required. ...
... Hence, the relative dimensions of these structural refinements will greatly affect the resultant MSS performance. In addition, the idea of adding an external DC coil around the outer PM of the original MSS [11] also provides adjustable magnetization for shifting the position of the erosion trench on the target. These observations clearly indicate that an enhanced performance can be achieved with proper combination of the feasible and applicable refinement parameters. ...
The DC magnetron sputtering systems (MSS) are widely applied in the microelectronic industries for thin film depositions. With their large installation volume in the related production lines, many efforts have been devoted to explore the possible refinements of the MSS structures that can improve the operational performance and reduce the target material consumption rates. Supported by qualitative and quantitative investigations, this paper describes a general guidance that can be applied to those commercial in-line DC MSS to control the magnetic field affecting the electron trajectories inside the sputterers. Results obtained from detailed studies on the systems with both single cylindrical magnetron and multiple rectangular magnetron structures showed that the proposed refinement scheme can increase the sputtering efficiency by over 25%, and the corresponding enhancements of substrate deposition rates are also to be expected. In addition, compared with those obtained without the refinements, the target erosion profiles with the refinements are more evenly spread out, thus reduction in the target material consumptions can also be expected.
