Evaluation of Post Etch Residue Cleaning Solutions for the Removal of TiN Hardmask after Dry Etch of Low-k Dielectric Materials on 45 nm Pitch Interconnects

2016 ◽  
Vol 255 ◽  
pp. 232-236
Author(s):  
Makonnen Payne ◽  
Steven Lippy ◽  
Ruben R. Lieten ◽  
Els Kesters ◽  
Quoc Toan Le ◽  
...  
Keyword(s):  
Titanium Nitride ◽  
Dielectric Materials ◽  
Plasma Etch ◽  
Novel Materials ◽  
Material Compatibility ◽  
Wet Etch ◽  
Dry Etch ◽  
Low K ◽  
Etch Residue

In the BEOL, as interconnect dimensions shrink and novel materials are used, it has become increasingly difficult for traditional PERR removal chemicals to meet the evolving material compatibility requirements. As a result, formulated cleans that specifically target these unique challenges are required. Two formulated BEOL cleans were evaluated on blanket and patterned wafer coupons for their ability to wet etch titanium nitride (TiN) and clean post-plasma etch residue, while remaining compatible to interconnect metals (Cu and W) and low-k dielectric (k = 2.4). Both, showed an improvement in material compatibility relative to dilute HF, while simultaneously being able to remove the TiN hardmask and post-etch residue, leading > 90% yield on test structures of varying sizes.

Surface Energy and Wetting Behaviour of Plasma Etched Porous SiCOH Surfaces and Plasma Etch Residue Cleaning Solutions

2009 ◽  
Vol 145-146 ◽  
pp. 319-322 ◽  
Author(s):  
Nicole Ahner ◽  
Matthias Schaller ◽  
Christin Bartsch ◽  
Eugene Baryschpolec ◽  
Stefan E. Schulz
Keyword(s):  
Surface Energy ◽  
Dielectric Materials ◽  
Solid Surfaces ◽  
Plasma Etch ◽  
Surface Energies ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Additional Process ◽  
Low K ◽  
Etch Residue

The removal of plasma etch residues by wet cleaning is an alternative or additional process to plasma processes, which are known to degrade low-k and ultralow-k dielectric materials. Besides Cu/low-k compatibility wetting is an important issue for wet cleaning. Surface energy of solid and liquid is the key to understand the wetting behaviour. In this study we examined the energetic character of plasma etched/stripped solid surfaces, etch polymers and several cleaning solutions by contact angle measurements. The results show, that variations of the etching process can heavily change the energetic character of the solid. Calculating the surface energies of solid and liquid provides the possibility to make a prediction if a cleaning liquid will wet the surface which has to be cleaned.

Selective High-Throughput TiN Etching Methods

2012 ◽  
Vol 195 ◽  
pp. 143-145 ◽  
Author(s):  
Emanuel I. Cooper ◽  
Rekha Rajaram ◽  
Makonnen Payne ◽  
Steven Lippy
Keyword(s):  
Titanium Nitride ◽  
High Throughput ◽  
Seed Layer ◽  
Wet Etching ◽  
Thermochemical Properties ◽  
Hard Mask ◽  
Acidic Solutions ◽  
Layer Deposition ◽  
Wet Etch ◽  
Dry Etch

Titanium nitride (TiN) is widely used as a hard mask film protecting the inter-level dielectric (ILD) before metal or plating seed layer deposition steps. It is common practice to use a wet etch in order to remove residues formed during the ILD dry-etch step, and at the same time to remove some or all of the exposed TiN. From its thermochemical properties, it might be predicted that wet etching of TiN should be easy, since it is quite unstable with respect to both plain and oxidative hydrolysis. For example, in acidic solutions at 25°C [1, :

Post Etch Residue Removal and Material Compatibility in BEOL Using Formulated Chemistries

2014 ◽  
Vol 219 ◽  
pp. 201-204 ◽  
Author(s):  
Els Kesters ◽  
Q.T. Le ◽  
D. Yu ◽  
M. Shen ◽  
S. Braun ◽  
...  
Keyword(s):  
Good Adhesion ◽  
Plasma Etch ◽  
Residue Removal ◽  
Fluorocarbon Plasma ◽  
Lift Off ◽  
Materials Used ◽  
Low K ◽  
Etch Residue ◽  
Processing Steps ◽  
Dielectric Degradation

A possible way to realize a 22.5 nm 1⁄2 pitch and beyond BEOL interconnect structures within the low-kmaterial is the partial-trench via first with self-aligned double patterning (SADP) integration approach. A scheme of this BEOL integration stack with the different materials used after patterning is described in Figure 1. In BEOL processing, fluorocarbon-containing plasma is commonly used to pattern silica-based dielectric layers. During the patterning of the low-kdielectric layer, a thin layer of fluoropolymer (CFx-type residues) is intentionally deposited on the dielectric sidewalls and TiN hardmask to ensure anisotropic etching and prevent/minimize dielectric degradation. This polymer layer must be removed from the sidewall and the via bottom prior to the subsequent processing steps to achieve good adhesion and coverage of materials deposited in the etched features. The compatibility requirement is even more stringent for advanced low-kdielectrics, i.e. materials with lowerk-value and higher porosity. The post etch residue (PER) amount and properties are specific and depend on the stack structure and the plasma that is used for patterning. The low-kmaterials and hardmasks that are used in this work are respectively an organo-silicate glass (OSG) type of low-kmaterial withk= 2.4 (~20 % open porosity) and low-stress TiN. Recent results clearly showed the presence of a highly fluorinated layer deposited on the trench sidewalls during the plasma etch based on a fluorocarbon plasma [1-3]. Commodity aqueous cleaning solutions, such as diluted HF, do not efficiently remove the sidewall polymers without etching the underlying layer (lift-off). Therefore, there is a need for commercially available chemicals that can be easily tuned to deal with the different requirements. This study focuses on the use of FOTOPUR® R 2300 mixed with H2O2 for polymer residue removal selectively to other materials (presented in the stack) such as MHM, metals (Cu, W), and porous low-k dielectrics. We will show that TiN etch can be easily tuned by changing the concentration of H2O2.

High Throughput Wet Etch Solution for BEOL TiN Removal

2016 ◽  
Vol 255 ◽  
pp. 245-250
Author(s):  
Chia Jung Hsu ◽  
Chieh Ju Wang ◽  
Sheng Hung Tu ◽  
Makonnen Payne ◽  
Emanuel Cooper ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
High Throughput ◽  
Etch Rate ◽  
Manufacturing Processes ◽  
Mixing Ratio ◽  
Strong Base ◽  
Wet Etch ◽  
Tin Removal ◽  
Low K ◽  
Etch Residue

Sub-10 nm technology node manufacturing processes may require the use of thicker and denser TiN hard mask for patterning at the BEOL. The modified TiN, which tends to be more chemically robust, must be removed using a wet etch process, while maintaining typical throughput - no extension of typical wet etch process times. To satisfy these needs, a new TiN etching accelerator was found that enhanced the activity of peroxide-related species in a wet etch chemical formulation that achieved increased TiN etch rate relative to formulation without TiN etch rate accelerator (Sample 1), while also minimizing the damage to ultra-low-k inter layer dielectric (ILD) layer by a strong base, also present in the formulation. We report here the result of a solvent based formulation, which adopted the TiN etching accelerator. The formulation was able to maintain TiN etch rate and remove post-etch residue, while remaining selective to ultra-low-k ILD, Co and Cu. The TiN etch rate of the accelerator enhanced formulation can be further tuned by modifying the process temperature or the hydrogen peroxide to formulation mixing ratio and has the potential capability to process > 400 wafers.

Optimized Wetting Behavior of Water-Based Cleaning Solutions for Plasma Etch Residue Removal by Application of Surfactants

2012 ◽  
Vol 187 ◽  
pp. 201-205 ◽  
Author(s):  
Nicole Ahner ◽  
Sven Zimmermann ◽  
Matthias Schaller ◽  
Stefan E. Schulz
Keyword(s):  
Surface Energy ◽  
High Surface ◽  
Application Of Surfactants ◽  
Plasma Etch ◽  
Promising Alternative ◽  
Wetting Behavior ◽  
Residue Removal ◽  
Wet Chemical ◽  
Low K ◽  
Etch Residue

Wet chemical plasma etch residue removal is a promising alternative to low-k dielectric degrading plasma cleaning processes. With decreasing feature dimensions the wetting behavior of the liquid on low energetic surfaces present after dielectric patterning will be an important issue in developing wet cleaning solutions. High surface energy liquids may not only be unable to wet low energetic surfaces, but can also cause nonwetting of small structures or pattern collapse. The improvement of the wetting behavior of a cleaning liquid by lowering its surface energy by the addition of surfactants is the strategy followed in this study. We show that with choosing the appropriate rinsing solution a wet chemical process using surfactant aided cleaning solutions compatible to the materials used in BEOL (porous low-k, copper, barriers) can be found. The results show a distinct improvement of the wetting behavior of the modified solutions on several low energetic solid surfaces like copper or polymers deposited during dry etching.

Novel Materials as Interlayer Low-K Dielectrics for CMOS Interconnect Applications

2011 ◽  
Vol 110-116 ◽  
pp. 5380-5383
Author(s):  
Tejas R. Naik ◽  
Veena R. Naik ◽  
Nisha P. Sarwade
Keyword(s):  
Dielectric Constant ◽  
Integrated Circuits ◽  
Dielectric Materials ◽  
Low Dielectric Constant ◽  
Interlayer Dielectric ◽  
Novel Materials ◽  
Low Dielectric ◽  
Processing Properties ◽  
New Generation ◽  
Low K

Scaling down the integrated circuits has resulted in the arousal of number of problems like interaction between interconnect, crosstalk, time delay etc. These problems can be overcome by new designs and by use of corresponding novel materials, which may be a solution to these problems. In the present paper we try to put forward very recent development in the use of novel materials as interlayer dielectrics (ILDs) having low dielectric constant (k) for CMOS interconnects. The materials presented here are porous and hybrid organo-inorganic new generation interlayer dielectric materials possessing low dielectric constant and better processing properties.

Dry and Wet Etch Processes for NiMnSb, LaCaMnO3 and Related Materials

1997 ◽  
Vol 494 ◽  
Author(s):  
J. Hong ◽  
J. J. Wang ◽  
E. S. Lambers ◽  
J. A. Caballero ◽  
J. R. Childress ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Smooth Surface ◽  
Dielectric Materials ◽  
Ion Density ◽  
Ion Energy ◽  
Sensor Devices ◽  
Etch Rates ◽  
Surface Morphologies ◽  
Wet Etch ◽  
Dry Etch

ABSTRACTA variety of plasma etching chemistries were examined for patterning NiMnSb Heusler thin films and associated A12O3 barrier layers. Chemistries based on SF6 and Cl2 were all found to provide faster etch rates than pure Ar sputtering. In all cases the etch rates were strongly dependent on both the ion flux and ion energy. Selectivities of ≥20 for NiMnSb over A12O3 were obtained in SF6-based discharges, while selectivities ≤5 were typical in Cl2 and CH4/H2 plasma chemistries. Wet etch solutions of HF/H2O and HNO3/H2SO4/H2O were found to provide reaction-limited etching of NiMnSb that was either non-selective or selective, respectively, to A12O3. In addition we have developed dry etch processes based on Cl2/Ar at high ion densities for patterning of LaCaMnO3 (and SmCo permanent magnet biasing films) for magnetic sensor devices. Highly anisotropie features are produced in both materials, with smooth surface morphologies. In all cases, SiO2 or other dielectric materials must be used for masking since photoresist does not retain its geometrical integrity upon exposure to the high ion density plasma.

Dry Etch and Wet Clean Process Characterization of Ultra Low-k (ULK) Material Nanoglass®E

2004 ◽  
Vol 812 ◽  
Author(s):  
B. Ramana Murthy ◽  
C.K. Chang ◽  
Ahilakrishnamoorthy ◽  
Y.W. Chen ◽  
Ananth Naman
Keyword(s):  
Process Integration ◽  
Dielectric Material ◽  
Process Technology ◽  
Plasma Etch ◽  
K Value ◽  
Process Characterization ◽  
Voltage Ramp ◽  
Dry Etch ◽  
Low K

AbstractNANOGLASS®E (NGE) ultra low-k (ULK) dielectric material, with a k-value of ∼2.2, was integrated for 130 nm Cu/ULK interconnect process technology. This work deals with the characterization of reactive ion etching (RIE) and wet chemical processing of this film. Blanket films were characterized for etch rate, surface roughness, k-value change and chemical compatibility. Trench etching and post etch wet clean processes were developed and optimized enabling process integration for single damascene structures. Trench etch processes were evaluated for two etch schemes viz., etching under - photo resist and etching under hardmask. The details of each scheme will be described and advantages observed will be discussed. To evaluate effect of wet clean processes three different formulations were used. After formation of single damascene wafers, metal comb and serpentine structures were measured for metal continuity and bridging. Electrical continuity was achieved for long serpentine structures with 0.18μm/0.18μm line width/spacing. Based on voltage ramp test results the film was found to be sensitive to certain plasma etch conditions.

Determination of Surface Energy Characteristics of Plasma Processed Ultra Low-K Dielectrics for Optimized Wetting in Wet Chemical Plasma Etch Residue Removal

2012 ◽  
Vol 195 ◽  
pp. 110-113
Author(s):  
Nicole Ahner ◽  
Sven Zimmermann ◽  
Matthias Schaller ◽  
Stefan E. Schulz
Keyword(s):  
Moisture Absorption ◽  
Plasma Processing ◽  
Reaction Products ◽  
Plasma Etch ◽  
Promising Alternative ◽  
K Value ◽  
Oh Groups ◽  
Residue Removal ◽  
Low K ◽  
Etch Residue

The integration of porous ultra low dielectric constant materials (ULK) for isolation within the interconnect system of integrated circuits is a promising approach to reduce RC-delays and crosstalk due to shrinking feature sizes [1]. Actually the focus is on porous CVD-SiCOH materials, which consist of a Si-O-Si backbone and organic species (e.g. CH3) to lower polarizability and prevent moisture uptake to remarkably decrease the k-value [2]. The integration of porous low-k materials is very challenging, especially looking at patterning, resist stripping and etch residue removal, where commonly plasma processing has been applied. But plasma processing of ULK materials, especially using oxygen plasmas, is known to degrade electrical, optical and structural material properties by removing carbon from the film and densification of the surface near areas of the ULK [5]. Carbon depletion may also lead to the incorporation of-OH groups, which easily form silanols and therefore increase moisture absorption and k-values [2]. Besides the development of nondamaging plasma processes, wet cleaning is a promising alternative to avoid ULK damage while removing organic plasma etch residues. Additionally wet cleaning steps are always necessary to remove inorganic residues, which do not form volatile reaction products and can therefore not be removed by plasma processing.

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