SEMI spoke with Dr. Mikko Söderlund, sales director for Beneq’s semiconductor business, about trends in Atomic Layer Deposition (ALD) applications. Söderlund shared his views ahead of his presentation at SEMI MEMS & Imaging Sensors Summit, 25-27 September, 2019, at the WTC in Grenoble, France. Join us at the event to meet Beneq and other key industry influencers. Registration is open.
SEMI: The Backside Illuminated (BSI) CMOS Image Sensors (CIS) market continues to experience steady growth. Which applications are currently driving market growth?
Söderlund: BSI CMOS Image Sensor market continues to be driven by mobile, security, automotive and Internet of Things (IoT) applications – so there seems to be plenty of opportunities for BSI CIS market to grow further.
SEMI: What is critical for advanced thin-film deposition methods to extract best electrical performance?
Söderlund: It is critical to control the material properties of the deposited layer (such as charge density, resistivity or barrier property) and of course, film uniformity and conformality. Furthermore, controlling material interfaces is also important, especially for sensitive III-V materials.
Coatings and material features based on existing standard techniques can be very expensive, or not feasible at all. What does Atomic Layer Deposition (ALD), as a thin film coating method, offer in particular?
Söderlund: ALD offers dense, highly conformal and pinhole-free best-in-class functional layers for dielectrics, passivation, encapsulation and much more. As a gentle and precise layer-by-layer method, ALD is extremely well-suited for deposition of such performance critical layers over large surface areas such as a cassette of wafers.
SEMI: Please describe the Atomic Layer Deposition (ALD) coating process.
Söderlund: ALD is based on a self-limiting surface reaction controlled thin film deposition. During coating, two or more chemical vapors or gaseous precursors react sequentially on the substrate surface, producing a solid thin film (see schematic below). Most ALD coating systems use a flow-through traveling wave setup, where an inert carrier gas flows through the system and precursors are injected as very short pulses into this carrier flow. The carrier gas flow takes the precursor pulses as sequential waves through the reaction chamber, followed by a pumping line, filtering systems and, eventually, a vacuum pump.
SEMI: What are the two leading edge ALD applications?
Söderlund: Today’s leading-edge ALD applications are in logic (high-k/metal gate, multiple patterning) and memory (DRAM capacitor, 3D NAND). Within the More-than-Moore (MtM) markets, CIS and MEMS (actuators and sensors, RF) have been early adopters of ALD, and we also see ALD being introduced in GaN Power and RF, as well as photonics.
SEMI: Give us one prediction about the opportunities offered by advanced imaging applications.
Söderlund: The large diversity of imaging applications will continue to drive growth and innovation. For example, machine vision is expected to transform the imaging landscape. We see this as a big opportunity for advanced thin-film deposition methods such as ALD, provided that the tools are versatile enough to address the diverse manufacturing requirements.
SEMI: What are your expectations for SEMI MEMS & Imaging Sensors Summit and why do you invite your peers to attend?
Söderlund: The summit brings together all key RF stakeholders in the MEMS and imaging sensors industry, and we are looking forward to a great event. It’s a special event for us as we are officially launching a new ALD cluster tool product specifically engineered for the MtM applications – so this brings great excitement that we want to share with the attendees.
Dr. Mikko Söderlund is Sales Director for Beneq’s semiconductor business. He has more than 20 years of experience in product development, product management, technical sales and business development across the photonics, OLED, and semiconductor industries.
Mikko received his Ph.D. in Micro- and Nanotechnology from the Helsinki University of Technology.
Serena Brischetto is a marketing and communications manager at SEMI Europe.