Etching Characteristics of Noble Metal Electrode

2000 ◽  
Vol 655 ◽  
Author(s):  
St. Schneider ◽  
H. Kohlstedt ◽  
R. Waser

AbstractThe objective of this work was to develop a process to pattern noble metal electrodes. To systematically investigate possible reactive etch process regions, characterized by volatile etch products, we used a reactive ion beam etching (RIBE) tool with a filament free ICP source. This configuration gives us exact control over the beam energy and the current density, and allows to use reactive gases. An energy dispersive quadrupole mass spectrometer is fitted to the chamber for in situ monitoring.We study the influence of the beam energy and the beam current impinging on the wafer surface as well as it's angular dependence. Several additives to the chlorinated process chemistry are investigated and characterized in terms of their role to help to increase the etch rate, maintain a vertical profile, or to enhance process selectivity.The main focus of the study is on Platinum. Blanket films were used to describe the influence of the material, and analysis were carried out to characterize the process in terms of etch rate, residues and selectivity.

2001 ◽  
Vol 688 ◽  
Author(s):  
St. Schneider ◽  
H. Kohlstedt ◽  
R. Waser

AbstractNoble metals like platinum or irdium are used as electrode materials in DRAM or FRAM devices. Their etch process is a challenge as conventional, sputter driven etch processes either result in redeposition problems (fences) or in a severe sloping (loss of dimension control) and are not acceptable for high density integration architectures. The high temperature etch regime offers a solution by increasing the chemical etch component and thus the volatility of the etch products.As previously reported, the platinum etch rate increases exponentially for a chlorine etch process with increasing wafer temperature. In this study we investigate the particular role of carbon monoxide in a Cl2/CO etch process. We find that carbon monoxide additions to a chlorine process boost the chemical component of the platinum etch rate very significantly, exceeding the effects in the chlorine only process regime by far. Additionally we compare these results with a Cl2/O2 and a Cl2/CO2 process chemistry, which are not found to be particularly beneficial.To better understand the etch process we use an energy dispersive quadrupole mass spectrometer for in situ monitoring, attached to the chamber at two different locations. We are able to position the probe orifice at the place of the wafer electrode, to record ion energy and ion mass spectra of species impinging on the wafer plane. A second off axis position allows for etch product monitoring.


2014 ◽  
Vol 71 (5) ◽  
Author(s):  
Someraa Saleh Shakonah ◽  
Jalil Ali ◽  
Natashah Abd. Rashid ◽  
Kashif Chaudhary

Some of ion beam properties have been investigated by using Lee model code on plasma focus devices which is operated with nitrogen and helium gases. The operation of plasma focus in different pressure regime gives a consistent ion beam properties which can make the plasma focus a reliable ion beam source .These ion beam properties such as ion beam flux, ion beam fluence, ion beam energy, ion beam current, and beam ion number corresponding to gas pressure have been studied for Mather type plasma focus device. The result shows the differences between helium as lighter gas and nitrogen as heavier gas in term of ion beam properties. The fluence and flux are decrease for nitrogen while increase for helium. 


MRS Advances ◽  
2017 ◽  
Vol 2 (4) ◽  
pp. 247-252
Author(s):  
Narasimhan Srinivasan ◽  
Katrina Rook ◽  
Ivan Berry ◽  
Binyamin Rubin ◽  
Frank Cerio

ABSTRACTWe investigate the feasibility of inert ion beam etch (IBE) for subtractive patterning of ReRAM-type structures. We report on the role of the angle-dependent ion beam etch rates in device area control and the minimization of sidewall re-deposition. The etch rates of key ReRAM materials are presented versus incidence angle and ion beam energy. As the ion beam voltage is increased, we demonstrate a significant enhancement in the relative etch rate at glancing incidence (for example, by a factor of 2 for HfO2). Since the feature sidewall is typically exposed to glancing incidence, this energy-dependence plays a role in optimization of the feature shape and in sidewall re-deposition removal.We present results of SRIM simulations to estimate depth of ion-bombardment damage to the TMO sidewall. Damage is minimized by minimizing ion energy; its depth can be reduced by roughly a factor of 5 over typical IBE energy ranges. For example, ion energies of less than ∼250 eV are indicated to maintain damage below ∼1nm. Multi-angle and multi-energy etch schemes are proposed to maximize sidewall angle and minimize damage, while eliminating re-deposition across the TMO. We utilize 2-D geometry/3-D etch model to simulate IBE patterning of tight-pitched ReRAM features, and generate etched feature shapes.


1987 ◽  
Vol 98 ◽  
Author(s):  
P. Kirk Boyer ◽  
Tim Verhey ◽  
Jorge J. Rocca

ABSTRACTA large area (2.8 cm2) electron beam source has been developed, characterized, and applied to anisotropic etching of SiO2 masked with photoresist. This beam operates at high pressures (up to 100 mTorr), in reactive gases, and at more than 10 mA/cm2. Beam current can be controlled in several ways independently from beam energy. The 100 – 900 eV low energy beam propagates with collimation through several cm of reactive gas, and is believed to minimize space charge defocusing by collisionally ionizing the working gas.


1997 ◽  
Vol 483 ◽  
Author(s):  
J. W. Lee ◽  
S. J. Pearton ◽  
C. R. Abernathy ◽  
G. A. Vawter ◽  
R. J. Shul ◽  
...  

AbstractMass spectrometry of the plasma effluent during Reactive Ion Beam Etching (RIBE) of GaAs using an Inductively Coupled Plasma (ICP) source and a Cl2/Ar gas chemistry shows that AsCl3, AsCl2 and AsCl are all detected as etch products for As, while GaCl2 is the main signal detected for the Ga products. The variation in selective ion currents for the various etch products has been examined as a function of chuck temperature (30–100°C), percentage Cl2 in the gas flow, beam current (60–180 mA) and beam voltage (200–800 V). The results are consistent with AsCl3 and GaCl3 being the main etch product species under our conditions, with fragmentation being responsible for the observed mass spectra.


2016 ◽  
Vol 87 (2) ◽  
pp. 02B930
Author(s):  
Y. Fujiwara ◽  
H. Sakakita ◽  
A. Nakamiya ◽  
Y. Hirano ◽  
S. Kiyama

Author(s):  
P.G. Pawar ◽  
P. Duhamel ◽  
G.W. Monk

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.


Author(s):  
B. Domengès ◽  
P. Poirier

Abstract In this study, the resistance of FIB prepared vias was characterized by the Kelvin probe technique and their physical characteristics studied using cross-sectional analysis. Two domains of resistivity were isolated in relation to the ion beam current used for the deposition of the via metal (Pt). Also submicrometer vias were investigated on 4.2 µm deep metal lines of a BiCMOS aluminum based design and a CMOS 090 copper based one. It is shown that the controlling parameter is the shape and volume of the contact, and that the contact formation is favored by the amount of over-mill of the via into the metal line it will contact.


2000 ◽  
Vol 655 ◽  
Author(s):  
Jay Hwang

AbstractProfile control, process repeatability and productivity concerns in etching Pt electrodes are reviewed specifically for application in fabricating high-density BST/Pt capacitors. The approach of using a high temperature cathode in a high-density reactive plasma chamber has produced a repeatable >85° Pt profile, stable etch rate and low particle results over a 500-wafer marathon test. A “corrosion-like” BST defect can be prevented by adding a post etch treatment to remove any corrosive residue from the wafer surface. A feasible manufacturing solution for etching BST/Pt capacitors for future high-density DRAM application is demonstrated.


In s.i.m.s. the sample surface is ion bombarded and the emitted secondary ions are mass analysed. When used in the static mode with very low primary ion beam current densities (10 -11 A/mm 2 ), the technique analyses the outermost atomic layers with the following advantages (Benninghoven 1973, I975): the structural—chemical nature of the surface may be deduced from the masses of the ejected ionized clusters of atoms; detection of hydrogen and its compounds is possible; sensitivity is extremely high (10 -6 monolayer) for a number of elements. Composition profiles are obtained by increasing the primary beam current density (dynamic mode) or by combining the technique in the static mode with ion beam machining with a separate, more powerful ion source. The application of static s.i.m.s. in metallurgy has been explored by analysing a variety of alloy surfaces after fabrication procedures in relation to surface quality and subsequent performance. In a copper—silver eutectic alloy braze it was found that the composition of the solid surface depended markedly on its pretreatment. Generally there was a surface enrichment of copper relative to silver in melting processes while sawing and polishing enriched the surface in silver


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