High-throughput area-selective spatial atomic layer deposition with integrated etching correction for low defectivity
Directing matter to create structures with atomic-level control of physical and chemical properties is a long sought-after goal in nanotechnology. The deposition of atoms at specific locations on a pre-patterned surface can boost advances in catalysis, energy harvesting, and semiconductor device fabrication. To fabricate advanced multilayered 3D devices with perfectly aligned features the current conventional manufacturing approach requires many lithography and etching steps (i.e. top-down). Innovative bottom-up techniques are required to replace or complement top-down fabrication schemes. One of the main emerging solutions is to implement self-aligned fabrication schemes, in which a material is deposited on a pre-determined area in a selective manner. Area-selective deposition can enable cost-effective options to create the above mentioned structures in a bottom-up approach.
The focus of this research project is to investigate area-selective deposition of thin-films in a spatial-atomic layer deposition (ALD) mode for semiconductor device fabrication. ALD is a layer-by-layer deposition method that allows for atomic-level control over thickness and material properties, resulting in conformal and uniform deposition over large area and high aspect ratio substrates. Such unique features stem from the fact that, in the most simple case, ALD relies on cyclic and self-limiting chemical reactions between the substrate surface and alternating exposure to a precursor and co-reactant.
TNO-Holst Centre has developed this technique as a high-rate deposition version of conventional time-sequenced ALD. The research objective is to find viable small molecule inhibitors that can be implemented for achieving high-selectivity as well as develop in-line etching correction processes to lower the defectivity. Central for this project is a good affinity for thin-film surface chemistry encompassing both cutting-edge deposition, pre-treatments and etching processes. The goal is to develop novel area-selective spatial ALD processes, etching correction steps and understand the underlying fundamentals.
Figure 1. Example of a selective deposition process with interleaved etch-back correction steps developed at Holst Centre. Here, SiO2 is selectively deposited on Si and not on ZnO as demonstrated by ex-situ spectroscopic ellipsometry monitoring of the SiO2 thickness (Figure 1a). Such an approach when extended to other materials/surfaces, may be used for bottom-up trench filling as schematized in Figure 1 (b-g).
The project will be carried out in collaboration with leading semiconductor manufacturer and equipment companies, where the aim is to develop novel area-selective spatial ALD processes. Depending on the pre-treatment, using small molecule inhibitors and the deposition chemistry, thin-film nucleation can be delayed only on specific target surfaces. This can be exploited to achieve area-selective ALD. In this project, you will use Fourier transform infrared spectroscopy (FTIR) to study the interaction of pre-selected chemicals with substrates that contain several pre-patterned surface coatings. This will serve as a starting point for studying and understanding the effect of such chemicals on the nucleation and growth behavior of nitrides and oxides on different starting substrates. You will study the thickness evolution and monitor the process during deposition as well as etching of materials on different surfaces, using ex-situ spectroscopic ellipsometry (SE). Advanced characterization techniques such as transmission electron microscopy (TEM) and low energy ion spectroscopy (LEIS) can be conducted at our project partners site.
You are an ambitious master student with both scientific and practical skills looking for an internship or master thesis of 9 months. You have a chemistry or applied physics background, with knowledge in the fields of surface chemistry and thin-film deposition. You are pro-active, independent and a good team player. Good communication skills in English are expected.
Literature research on area-selective ALD and surface chemical modification
Perform deposition experiments and characterization measurements
Discuss and present the results internally as well as externally
Participate in group meetings, provide feed-back, discuss results, and propose solutions to various challenging aspects
Write technical internship report
What can you expect of your work situation?
TNO is an independent research organization whose expertise and research make an important contribution to the competitiveness of companies and organizations, to the economy and to the quality of society as a whole. Innovation with purpose is what TNO stands for. With 3000 people we develop knowledge not for its own sake but for practical application. To create new products that make life more pleasant and valuable and help companies innovate. To find creative answers to the questions posed by society. We work for a variety of customers: governments, the SME sector, large companies, service providers and non-governmental organizations. Working together on new knowledge, better products and clear recommendations for policy and processes. In everything we do, impact is the key. Our product and process innovations and recommendations are only worth something if our customers can use them to boost their competitiveness.
What can TNO offer you?
You want to work on the precursor of your career; a work placement gives you an opportunity to take a good look at your prospective future employer. TNO goes a step further. It is not just looking that interests us; you and your knowledge are essential to our innovation. That is why we attach a great deal of value to your personal and professional development. You will, of course, be properly supervised during your work placement and be given the scope for you to get the best out of yourself. Naturally, we provide suitable work placement compensation (~500 €/month).