Rapid Recovery Process of Plasma Damaged Porous Low-k Dielectrics by Wet Surface Modifying Treatment

2016 ◽  
Vol 255 ◽  
pp. 223-226
Author(s):  
Akihisa Iwasaki ◽  
Ayumi Higuchi ◽  
Kana Komori ◽  
Masanobu Sato ◽  
Els Kesters ◽  
...  
Keyword(s):  
Hydrophobic Surface ◽  
Recovery Process ◽  
Repair Process ◽  
Process Time ◽  
High Quality ◽  
Rapid Repair ◽  
Residue Removal ◽  
Metal Materials ◽  
Low K ◽  
Etch Residue

A rapid repair process of plasma damaged SiCOH in combination with post-etch residue removal has been developed. The carbon depletion layer caused by plasma dry etching was repaired by subsequent surface modifying SAM treatment, which resulted in replenishment of carbon not only on the surface but also a few nm toward the bulk. This repairing technique provides a high-quality hydrophobic surface under conditions of low temperature and short process time. In addition, the SAM layer can be expected to act as an adhesion promotor with metal materials.

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.

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.

TiN Metal Hardmask Etch Residue Removal on Advanced Porous Low-k and Cu Device with Corner Rounding Scheme

2012 ◽  
Vol 187 ◽  
pp. 241-244 ◽  
Author(s):  
Hua Cui ◽  
Martine Claes ◽  
Samuel Suhard
Keyword(s):  
Etch Rate ◽  
Room Temperature ◽  
Complete Removal ◽  
Cleaning Process ◽  
Residue Removal ◽  
Tin Metal ◽  
User Friendly ◽  
Low K ◽  
Etch Residue

A novel wet cleaning formulation approach was developed with a TiN etch rate of more than 30 Å/min at room temperature and more than 100 Å/min at 50°C. The chemicals are compatible with Cu and low-k materials, and are suitable for Cu dual damascene interconnect 28 nm and smaller technology node applications. The chemicals offer a route to in situ controlled TiN pullback or even complete removal of the TiN mask during the cleaning process in single wafer tool applications. The chemicals do not contain NH4OH or TMAH and so are very user-friendly.

Characterization of Etch Residues Generated on Damascene Structures

2016 ◽  
Vol 255 ◽  
pp. 227-231
Author(s):  
Quoc Toan Le ◽  
Els Kesters ◽  
I. Hoflijk ◽  
T. Conard ◽  
M. Shen ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Residue Removal ◽  
One Step ◽  
Low K ◽  
Etch Residue

For patterned TiN/silicon oxide/low-k dielectric stack, fluorinated etch residues were detected on the TiN surface, the dielectric sidewall and bottom, regardless of the low-k material used in the stack. XPS results showed that they consisted of polymer-based (CFx) residues deposited on trench sidewall and bottom, and metal-based (TiFx) residues mainly deposited on top surface. In terms of post-etch residue removal, the efficiency of various wet clean solutions can be clearly distinguished for CFx, and TiFx using the same patterned porous low-k stack. These results also demonstrate that the removal of both TiFx and CFx residues generated during the plasma is possible in one step with optimized chemical and process.

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.

Improved Cleaning Process for Etch Residue Removal in an Advanced Copper/Low-k Device without the Use of DMAC (Dimethylacetamide)

2012 ◽  
Vol 187 ◽  
pp. 245-248
Author(s):  
Chung Kyung Jung ◽  
Sung Wook Joo ◽  
Sang Wook Ryu ◽  
S. Naghshineeh ◽  
Yang Lee ◽  
...  
Keyword(s):  
High Selectivity ◽  
Dry Etching ◽  
New Materials ◽  
Process Step ◽  
Residue Removal ◽  
The Past ◽  
Microelectronic Fabrication ◽  
Etching Mask ◽  
Low K ◽  
Etch Residue

Plasma dry etching processes are commonly used to fabricate sidewalls of trenches and vias for copper / low-k dual damascene devices. Typically, some polymers remain in the trench and at the via top and sidewall. Other particulate etch residues are may remained in the bottom and on the sidewalls of vias. Generally, the particulate consists of mixtures of copper oxide with polymers. The polymers on the sidewalls and the particulate residues at the bottom of vias must be removed prior to the next process step. Small amounts of polymer are intentionally left on the sidewalls of trenches and vias during the etching in order to achieve a vertical profile and to protect the low-k materials under the etching mask. Until now, the industry has relied mainly on organic solvent containing mixtures to clean etch / ash residues from such devices. The effectiveness of available residue removers varies with the specific process and also depends on which new integration materials are used. New materials typically include Cu, TaN, low-k dielectrics and others [1-. Solvent content is thought to aid the removal of polymer residues and particulates produced during plasma dry etching processes. Therefore, in the past we have used a residue remover which contains DMAC (dimethylacetamide). But the use of DMAC is banned in microelectronic fabrication facilities in Europe because of its toxicity. Thus we wanted to find and evaluate a DMAC-free residue remover for removing polymer residues while maintaining high selectivity to the copper and ILD films.

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