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Arc handling considerations for DC sputtering DC power supplies
Abstract
Sputtering is an important physical vapor deposition (PVD) method in the manufacture of many products. However, sputtering processes are prone to arcing, which can cause damage to the work piece. Therefore, arcs must be detected and extinguished in a timely manner to minimize damage. Instantaneous arc rate and total arcs per process step are useful data for assessing PVD chamber health, and determining when maintenance is required. Arc handling is now a standard feature of many PVD power supplies. It is beneficial for the PVD power supply to include a digital communication interface to allow the host control system to access the arc sensor data and to dynamically configure the arc handling settings. The sputtering process arcing problem will be reviewed, including references to early experimental work implying the influence of oxides in the glow to arc transition, as well as selected history of the evolution of arc handling for sputtering processes. PVD power supplies, with the ability to report arc frequency and total arc count, will be discussed. Finally, automated target conditioning enabled by integrated arc handling will be presented. It gradually increases output power in an adaptive manner, minimizing arcing, until the target is fully conditioned.
... It is clear, that processes in the arc develop in accordance with the given conditions until it is detected. At a quick arc detection together with the high switching speed of modern transistors, the arc energy density in MFMS can be reduced to several millijoules and less [40]. On the strength of some reasons, the arc energy in HiPIMS is considerably high. ...
... According to Refs. [40,76], the voltage drop enables a prompt arc detection by the control system. The maximum discharge current I m.vad is observed within t 6 -t 7 period equaling the delay time t del . ...
High-power impulse magnetron sputtering (HiPIMS) is rather a new and rapidly developing method for physical vapor deposition of thin films. Due to a high ionization degree of the sputtered material, the HiPIMS coatings have better properties than those produced by conventional DC magnetron sputtering (DCMS) and mid-frequency magnetron sputtering (MFMS). Along with its advantages, HiPIMS has some disadvantages, which make difficult its application. HiPIMS is characterized by the high pulsed discharge current, which provides higher arc frequency and energy than in MFMS and DCMS. This leads to larger defect size and quantity that appear in the coating obtained. This paper proposes the analytical simulation model to describe the discharge current and discharge voltage during arcing. This model helps to calculate the arc energy, lifetime, and maximum current. It also identifies what parameters of the power supply exert the highest effect on the arc parameters. The paper considers the types of the HiPIMS power supply and compares them with the view of arc quenching effectiveness. The model adequacy is verified by the experimental results of measurement the arc parameters in HiPIMS. It is shown the effect of arc energy on the size and number of defects in the carbon coatings obtained in HiPIMS.
... [24][25][26][27]. Mid-frequency pulsed dc magnetron sputtering (PDCMS) is a well-developed sputtering technique that, after the main negative pulse for sputtering, utilizes a positive pulsed voltage to neutralize the charge on the target surface and eliminate arcing by appropriately controlling the pulsing parameters [28]. Therefore, the purpose of using DOMS and PDCMS as sputtering sources in this study is to enhance the ion bombardment on the coating under a virtually arc free deposition environment. ...
Beschichtungen auf Architekturverglasungen werden heute überwiegend für Wärme- und Sonnenschutz, als Leitschichten in der Photovoltaik sowie in Kombination mit diesen Anwendungen oder getrennt davon zur Entspiegelung, Verspiegelung und für die Selbstreinigung auf Verglasungsaußenoberflächen bei Bewitterung eingesetzt. Hierzu sind Anlagen erforderlich, auf denen Scheiben mit Abmessungen bis zu 3,21m x 6,00m beschichtet werden können. Schichten, mit denen insbesondere Energie eingespart wird, z.B. in Verbindung mit Wärme- und Sonnenschutzgläsern oder mit denen Sonnenenergie umgewandelt wird, z.B. in Photovoltaikmodulen, sind von großem wirtschaftlichem Interesse.
Beschichtungstechnologien für die oben genannten Scheibenabmessungen setzen ein hohes Maß an Erfahrungen mit der Physik dünner Schichten voraus. Die wichtigsten Prozesse sind chemische Verfahren bei Atmosphärendruck oder Magnetronsputtern unter Hochvakuum. Der folgende Bericht gibt einen historischen Überblick über die Entwicklung der vakuumbasierten Beschichtungsprozesse für Architekturglas.
Vacuum Coating of Architectural Glass - A Historic Review
Coatings on architectural glass nowadays are used to minimize the energy necessary for heating or cooling of buildings, as transparent conductors for photovoltaics, for mirrors or glazings with low reflection, and for self-cleaning windows. Modern architectural glass coaters are able to handle panes with a size of up to 3.21m x 6m and have an annual throughput of 5 to 10 millions of square meters per year.
Coating technologies for these dimensions require an extreme amount of experience in the physics of thin films. The most important deposition processes are chemical processes at atmospheric pressure and magnetron sputtering under high vacuum. This article reports on the history of vacuum coating of architectural glass.
A recent development in the plasma power supply market available are DC power supplies which are equipped with a programmable active arc out circuitry which is operating independently of the generation unit for the DC power. This type of power supply allows for extremely fast and programmable reaction to process instabilities. The energy delivered to the arc, the trigger conditions for a short and long arc out cycles, delay times and off times for the different arc out levels can freely be adjusted. In addition, the arc switch available can be triggered form an oscillator and run in a continuous pulse mode and, thus prevent excessive charging effects on insulating layers if necessary. The variety of possible settings of those power supplies offers a great possibility to tune the reaction of the power supply to the needs of the process, however, at the same time it bears the risk of mis-adjustment and consequently may lead to unsatisfying results if tuned improperly. In this paper the application of high power DC supplies with fast arc suppression to reactive zinc oxide and indium oxide processes is discussed with regard to the special process adjustment needs. In the case of oxide mode ZnO and In2O3 processes it is found that there is obviously an optimum arc energy that does not necessarily equals the minimum arc energy that can be realized by the power supply.
Pulsed dc power supplies provide enabling capability to dielectric reactive sputtering applications due to their ability to reduce or even eliminate arcing during the deposition process. As this technology matures there has been increasing interest in the semiconductor, optical and industrial coating industries to use pulsed-dc sputter supplies for difficult to deposit films. The fundamental behavior of reverse-voltage pulsing and its ability to reduce arcing has been studied [1,2] but little work has been published on optimizing the available parameters to provide maximum rate, minimum arc activity and maximized process stability and system utilization. Pre-vious studies have shown that in the range of 20 to 100 kHz there is a strong relationship between arc activity and reverse pulse time. In one study a critical duty factor was identified at a pulsing frequency of 60 kHz where arc free operation was obtained over an extended operating period [1]. This paper intends to expand upon these findings to explore whether an optimum duty factor may be established throughout the avail-able frequency spectrum of today's generation pulsed-dc power supplies. Furthermore, little is understood of how arc intensity, i.e. energy released during the arc, can affect pro-cess stability and longevity. Recent technological advances in pulsed-dc power supplies have allowed the range of pulsing frequencies to extend beyond 300 kHz and system architec-ture now allows for arc intensity discrimination. This study capitalizes on these capabilities as well as the more traditional controls of reverse time (duty factor) and reverse voltage in an effort to characterize their relationship to arc density, and long term process reliability during the reactive deposition of dielectric Al 2 O 3 .
IN the carbon- and tungsten-arc the electrons are in most cases emitted thermionically by the cathode, while in the mercury-arc (with mercury cathode) the cathode current is assumed to be due to the emission of electrons from a cold cathode by the high field before the cathode (field current). This high field is generated by the space charge of the positive ions flowing to the cathode.
This paper describes the control and reduction of agglomeration of the thin copper seed layer deposited on different barrier layers. Higher stress is applied in layers deposited on TaN and Ta barrier layers. This stress greatly affects the agglomeration and adhesion strength. This stress can be reduced markedly with employing a TaSiN barrier layer instead of Ta barrier layer. Correlations have been found between the stress in as-deposited copper seed layer and the agglomeration height formed with this annealing. That is, agglomeration occurs markedly in the layer on tantalum nitride (TaN) and Ta barrier layers. Although lower stress layer can be accomplished at the Cu seed/TaSiN interface, no agglomerations occur in the TaSiN barrier layer. This barrier layer for copper diffusion can also get promising barrier performance. (C) 2001 The Electrochemical Society.
We describe an example of the use of a high-speed camera in the study of transient phenomena in planar magnetron discharges. Low-current, spontaneous arcs are used to inject a stream of electrons into a magnetron plasma. Fast imaging of the arcs shows how the perturbation produced by the injected electrons travels in the E×B direction with minimum average speeds of approximately 7.4×105 m s−1.
One of the most important processing steps during copper
metallization is the deposition of a thin yet conformal copper seed
layer, often using ionized physical vapor deposition, prior to
electroplating. A key need in designing this step is assuring that
copper of sufficient thickness is deposited at all points within a high
aspect ratio (AR) feature. In this work, we present feature evolution
simulations of copper seed layer deposition, using ion reflection and
neutral copper sputtering distributions calculated using molecular
dynamics simulations. Independent variables in the model include
neutral-ion and ion-ion flux ratios as well as substrate bias voltage.
We show that trenches of AR=5 can be conformally lined with proper
variation of these independent variables using a simple composition and
ion energy cycling strategy. Furthermore, we show that the use of
reflection and sputtering distributions obtained by molecular dynamics
simulation results in qualitatively different feature shape predictions
than when using isotropic (cosine) sputtering distributions with no
possibility of ion reflection, with the degree of difference a function
of the ion-neutral flux ratio and the ion energy