Thursday, January 30, 2020

Picosun’s ALD technology helps to fight climate change

ESPOO, Finland, 30th January 2020 – Picosun’s Atomic Layer Deposition (ALD) thin film barrier coating technology offers a solution for eliminating the use of hazardous process gases, sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3).

In the current Chemical Vapor Deposition (CVD) coating methods, relatively thick films need to be grown to obtain the desired level of performance to reach the required specifications in e.g. moisture barrier, corrosion protection, passivation or insulation applications. Due to the fast film build-up on the walls of the coating equipment, the deposition chamber has to be cleaned of film residues at regular intervals. This is typically done by a chamber cleaning process with SF6 or NF3 plasma.

SF6 is the strongest greenhouse gas ever known, with global warming potential of 22600 times that of CO2 (for NF3, the coefficient is 17200) and it stays in the atmosphere for at least 1000 years (*). SF6 emissions in the EU in 2017 alone had greenhouse gas effect equalling that of 1,4 million cars (**). Hence, usage of these gases is subject to constant scrutiny and increased regulation.

By switching to Picosun’s ALD nanolaminate barrier technology it is possible to obtain unmatched barrier performance with extremely thin, pinhole-free films. This also eliminates the need to clean the deposition equipment after every few process runs. In typical production use, Picosun’s ALD reaction chamber is cleaned only once per 3 – 6 months, and simple mechanical bead blasting instead of fluorine-based plasma treatment is enough.

“We at Picosun want to employ our ALD technology for sustainable future. Fighting the climate change by all possible means requires collaboration between the innovative industries and solution providers. By replacing thick coatings, manufactured with environmentally compromising, energy- and resource-intensive methods, with our ultra-thin ALD film stacks, significant material and cost savings are obtained and hazardous gases are not needed in equipment cleaning,” summarizes Mr. Juhana Kostamo, deputy CEO of Picosun Group.

Picosun provides the most advanced AGILE ALD® (Atomic Layer Deposition) thin film coating solutions for global industries. Picosun’s ALD solutions enable technological leap into the future, with turn-key production processes and unmatched, pioneering expertise in the field – dating back to the invention of the technology itself. Today, PICOSUN® ALD equipment are in daily manufacturing use in numerous leading industries around the world. Picosun is based in Finland, with subsidiaries in Germany, North America, Singapore, Taiwan, China and Japan, offices in India and France, and a world-wide sales and support network. Visit

(*) J-C. Cigal “On-site fluorine chamber cleaning for semiconductor thin-film processes: Shorter cycle times, lower greenhouse gas emissions, and lower power requirements”, DOI: 10.1109/ASMC.2016.7491126

(**) P. Widger “Evaluation of SF6 leakage from gas insulated equipment on electricity networks in Great Britain”, DOI: 10.3390/en11082037

Molecular Layer Etching of Metalcone Films Using Lithium Organic Salts and TMA

Here is an new important paper on  by reseachers at Argonne National Laboratory, USA. It describes a new technique for the precise removal of metal–organic thin films deposited by molecular layer deposition (MLD), now to be known as term molecular layer etching.

Molecular Layer Etching of Metalcone Films Using Lithium Organic Salts and Trimethylaluminum

Matthias J. YoungDevika ChoudhurySteven LetourneauAnil ManeAngel Yanguas-GilJeffrey W. Elam
Chem. Mater. 2020, XXXX, XXX, XXX-XXX
Publication Date:January 15, 2020

Advances in semiconductor device manufacturing are limited by our ability to precisely add and remove thin layers of material in multistep fabrication processes. Recent reports on atomic layer etching (ALE) have provided the means for the precise removal of inorganic thin films deposited by atomic layer deposition (ALD), opening new avenues for nanoscale device design. Here, we report on a new technique for the precise removal of metal–organic thin films deposited by molecular layer deposition (MLD), which we term molecular layer etching. This etching process employs sequential exposures of lithium organic salt (LOS) and trimethylaluminum (TMA) precursors to produce self-limiting etching behavior. We employ quartz crystal microbalance experiments to demonstrate (i) etching of alucone films preloaded with LOS upon TMA exposures and (ii) layer-by-layer etching of alucone films using alternating exposures of LOS and TMA. We also identify the selectivity of these etching mechanisms. We probe the mechanism for the layer-by-layer etching of alucone using a quartz crystal microbalance and Fourier transform infrared spectroscopy and identify that the etching proceeds via heterolytic cleaving of Al–O bonds in alucone upon LOS exposure followed by methylation to produce volatile species upon TMA exposure. The etching process results in the removal of 0.4 nm/cycle of alucone at 160 °C and up to 3.6 nm/cycle of alucone at 266 °C in ex situ etching experiments on silicon wafers. This halogen-free etching process enables etching of MLD films and provides new fabrication pathways for the control of material geometries at the nanoscale.

Wednesday, January 29, 2020

The Coventor's SEMulator3D software platform

Semiconductor process engineers would love to develop successful process recipes without the guesswork of repeated wafer testing: Process modeling is a powerful technique to predict process results quickly and locate potential process issues without wafer-based testing. These process-modeling capabilities are fully-integrated in the Coventor's (a Lam Research Company) SEMulator3D software platform. Once a process model is built in SEMulator3D, any changes to a proposed integration scheme or device design (such as layout or hardmask thickness changes) can be easily visualized and quantified, without the time and expense of wafer testing. 

The process of building a 3D device using a process model (instead of physical wafers) is called “virtual fabrication”. Using virtual fabrication in conjunction with calibration cycles, process engineers and integration engineers can easily develop a process and integration model. The accuracy and predictability of any model is dependent on the quality of the input data, but SEMulator3D is able to model a wide range of physical process behavior with great accuracy and can solve highly-advanced process problems.

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Source: An Introduction to Semiconductor Process Modeling: Process Specification and Rule Verification (LINK)

By Abhishekkumar Thakur

Tuesday, January 28, 2020

Atomic layer 3D printing awarded with 3 million EUR funds by EU

European consortium led by FAU receives funding from the European Union in the 'Fast Track to Innovation' programme

The prospects of additive manufacturing (3D printing) as a versatile tool for prompt and inexpensive prototyping are extremely promising. This family of methods are set to make fabrication processes faster, more efficient in terms of the raw materials and energy required, and more flexible. However, additive manufacturing has not yet been broadly applied to micro and nanotechnology. Lithography, as the methods used for structuring in microelectronics are called collectively, is based on the repetition of complex multistep procedures in each of which a so-called "resist" that serves as a template is applied and later removed. Not only is current lithography slow, it also wastes materials and energy, is poorly adapted to combining a large number of distinct materials, and extremely costly in terms of capital expenses.

Left: Prof. Dr. Julien Bachmann, center Dr. Maksym Plakhotnyuk, right Ivan Kundrata (Photo credit ATLANT3D)

A team of scientists and engineers led by Prof. Julien Bachmann from FAU plan to combine the expertise of the various consortium partners in the chemical control of ultrathin coatings ("atomic layer deposition"), in gas delivery, microelectromechanical devices, and microprocessing and automation, in order to demonstrate the potential of "atomic-layer 3D printing", that is, the generation of arbitrary shapes with a vertical resolution in the order of one atom (or a tenth of one nanometer).

The consortium includes the companies ATLANT 3D Nanosystems, Femtika, and SEMPA Systems as well as the Institute of Electrical Engineering of the Slovak Academy of Sciences and FAU, and will be funded by approximately 3 million euros over a period of two years in the framework of the European Union's "Fast Track to Innovation" programme. The goal of the project is to design, build and test an industrial prototype of the atomic-layer 3D printer that can then be sold commercially.

ATLANT3D demonstrate high precision ALD printing

ATLANT3D report that they have completed successfully testing of their atomic printing system and could print first simple geometries and patterns. ATLANT3D technology relies on selective area direct atomic layer deposition process and enables direct pattern generation with atomic precision at 20 nm and 100-400 micrometer lateral resolution. 

Next chance to meet ATLANT3D will be at EFDS ALD for Industry 2020 in Freiburg April 1, 2020 (LINK) where CEO & Founder Dr. Maksym Plakhotnyuk will present "Direct atomic pattern printing"


Intermolecular use the VTT PillarHall(R) ALD high-aspect ratio test chip

Intermolecular (now part of the Performance Materials business unit at Merck) reports that using a platform developed by VTT Technical Research Centre of Finland, it has developed a simpler screening method for looking at the properties of films deposited into high aspect-ratio structures.

The VTT PillarHall® chip consists of membranes suspended above a silicon substrate and supported by nanoscale pillars, which can also be described as horizontal trenches.

The advantage of using this type of structure is that instead of needing cross-sections, simple planar metrology techniques can be used, and sample preparation is as easy as “dep, stick, rip!” The film is deposited on the trenches by ALD, a piece of sticky tape is attached to the sample and peeled off, and then any standard planar metrology technique can be used, for example, optical microscopy or SEM/EDX. (Credit :Intermolecular/VTT PillarHall® )

Fulla article: Intermolecular "ALD in Confined Spaces" LINK

Saturday, January 25, 2020

Chlorine-free titanium ALD precursor for leading edge semiconductor applications

Strem´s TDMAT ALD precursor as an attractive alternative to TiCl4

Atomic layer deposition (ALD) of titanium-based compounds has been a crucial process step in the modern semiconductor industry. Titanium nitride (TiN), due to its high electrical conductivity, has been in use as an inorganic anti-reflective coating for lithography, hard-mask for low-κ patterning, transistor gate electrodes, and diffusion barrier for tungsten contacts and Cu interconnects. Intel, in its 10nm, 3rd generation FinFET based technology node, employs a conformal Ti layer to wrap around source/drain diffusion regions to lower the spreading resistance (Link). Apple’s A11 bionic processor chip based on TSMC’s 10nm technology and Samsung’s Exynos 8895 processor chip based on its 10nm technology also incorporates Ti-based liners for tungsten contacts (Link). Globalfoundries and IBM Research investigated cobalt as a replacement of tungsten in the contacts for advanced semiconductor chips, and this process also incorporated a TiN barrier and a Ti liner (Link). TiN electrodes have also been promising for ferroelectric memory applications.

Figure 1:  Cross-section, perpendicular to the fin direction, TEM images on the 6T-SRAM area for (a) A11 and (b) Exynos8895. Images (c) and (d) are corresponding EDS mappings of (a) and (b), respectively. (Picture credit: MSSCORPS CO., LTD.)

Titanium dioxide (TiO2) is also an attractive candidate for several thin-film applications, such as high-k material for electronic devices, anti-reflection optical coatings, biocompatible coatings, photocatalysis, and solar cells. Besides, TiO2 is also a constituent of several crucial multi-metal oxide systems, such as strontium titanates (STOs), barium strontium titanates (BSTs), and lead zirconium titanates (PZTs), for dielectric and ferroelectric applications.

The TiCl4 precursor has been widely used to deposit Ti-based thin-films. However, due to severe Cl contamination, low growth per cycle, the corrosive nature of the reaction by-product (mainly HCl), high process temperature, and lower reactivity of TiCl4, the industry switch over to metal-organic precursors is swiftly gaining traction.

Strem Chemicals, Inc., a leading fine chemicals supplier, headquartered in Newburyport, Massachusetts, USA, boasts a vast variety of metal-organic precursors for depositing superior Ti-based thin-films in semiconductor as well as non-semiconductor applications. TDMAT [tetrakis(dimethylamino)titanium(IV)] (Product Catalog Number: 93-2240, CAS Number: 3275-24-9) is one of the most preferred high-purity metal-organic precursors in Strem’s chemical offering. Highly volatile and reactive TDMAT offers adequate vapor pressure even at room temperature and enables low temperature (< 140°C) deposition of high-quality Ti-based thin-films.

Figure 2: TDMAT molecule
Since 1964, Strem Chemicals, Inc. has been serving its clients from academic, industrial and government research and development laboratories as well as commercial scale businesses in the pharmaceutical, microelectronic and chemical/petrochemical industries. Strem also provides custom synthesis (including high-pressure synthesis) and current good manufacturing practice (cGMP) services. With ISO 9001 certification for Quality Management System (QMS) standard and documentation, most of Strem’s products are of reliable high purity, typically 99%, with some at 99.9999% metals purity. Strem utilizes a comprehensive range of analytical techniques tailored to each product to ensure quality because the researchers typically rely on the supplier's quality procedures and documentation, which may be detrimental to a great research idea if poorly conducted. All of Strem's catalogs, since inception, have listed “Color and Form” for every product as primary indicators of quality.

More than fifty years of experience in manufacturing inorganic and organometallic chemicals has enabled Stem to expand its product offering of MOCVD, CVD, and ALD precursors. They are continually adding new products for this dynamic and exciting field. Strem’s product range includes:

Product mentioned in this blog:
93-2240: Tetrakis(dimethylamino)titanium(IV), 99% TDMAT (3275-24-9)

Related Product Lines & Resources:
CVD & ALD Precursors
MOCVD, CVD & ALD Precursors Booklet
See full Material Science product line
Promotional Blog for Strem Chemicals, Inc.
Researched, produced & written by BALD Engineering AB, Stockholm, 2020-01-25
Abhishekkumar Thakur, Jonas Sundqvist