Deep Trenches Cleanliness Challenges for CMOS Image Sensors

Garnier, Philippe; Dignat, Franck; Buttet, C. de

doi:10.1149/08002.0101ecst

Cited by 5 publications

(7 citation statements)

References 2 publications

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“…In these two examples, a mild SC1 can dissolve these salts, or a plasma process can degas them from the surfaces. Eventually, wet processes can also meet airborne molecular contamination concerns [6], especially when using concentrated acids (sulfuric [7], or phosphoric acid [8]). They can leave a significant amount of anions on the substrate surface, if not properly cleaned, forming ammonium based salts.…”

Section: Resultsmentioning

confidence: 99%

Airborne Molecular Contamination: Mechanism and Consequences on Devices

Garnier¹,

Borde²,

Sevilla³

2022

ECS Trans.

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During dies manufacturing, silicon surfaces cleaning continues to be challenged to reduce materials consumption. There’s a trade-off between such reduction and keeping a good enough cleaning efficiency to avoid defects creation. This paper gives a few examples of chemical traces deposited on various surfaces, degrading the dies quality such as corrosion concerns and device electrical properties shifts.

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Section: Resultsmentioning

confidence: 99%

Airborne Molecular Contamination: Mechanism and Consequences on Devices

Garnier¹,

Borde²,

Sevilla³

2022

ECS Trans.

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“…The DTI [1,7] (Deep Trench isolation) silicon wafer is an etched silicon structure with trenches width of 200 nm, organized as a network of rectangles. Although the DTI wafer is made of silicon, there are two additional layers which are silicon dioxide (SiO2) and silicon nitride (Si3N4) of several tens of nanometers in thickness, present uniquely on the top surface of the trenches.…”

Section: Resultsmentioning

confidence: 99%

“…4, which will be used to calculate the fluid film thickness (h); then we will take our micro-channel height as 2h to achieve the same fluid flow profile, since it is a closed channel compared to the open jet system used in cleaning industrial wafers. Different aspect ratios of DTI [1,7] within silicon wafers, and covered by a PDMS micro-channel, have been tested and subjected to different hydrodynamic conditions. Table 1 show the hydrodynamic conditions on 300 mm flat wafer and the corresponding pressure loss calculated using Eq.…”

Section: Methodsmentioning

confidence: 99%

“…In the microelectronics industry the tendency for miniaturization of the electronic components has led to the fabrication of micro and nanostructures with high aspect ratios (for example structures of hundreds of nanometers wide and tens of micrometers height). With these increasing aspect ratios it's becoming more and more difficult to achieve wet cleaning of these etched silicon structures [1] and to remove non-desired particles which can lead to defective electronic products. We developed an acoustic method [2,3] using ultra-high frequency (5 GHz) to detect the penetration of the liquid to the bottom of the etched structure and hence get information about the efficiency of the wetting (cleaning) states.…”

Section: Introductionmentioning

confidence: 99%

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Polydimethylsiloxane Micro-Channels Application for the Study of Dynamic Wetting of Nano-Etched Silicon Surfaces Based on Acoustic Characterization Method

Salhab

Carlier

Campistron

et al. 2021

SSP

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Efficient cleaning of contaminations in the semiconductor industry is a determining factor in ensuring the good quality of the electronics products. We present here the dynamic wetting characterization of a fluid on top of DTI structures using ultra-high frequency acoustic method. The dynamics of the fluid will be established using a PDMS micro-channel placed on top of the structures, in order to obtain conditions as close as possible to those used in the industrial process. Wetting state of the DTI structures is determined based on the measured acoustic reflection coefficient.

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“…In the first part of this paper, we will present an application of the acoustic method to characterize the wetting over a Deep Trench Isolation (DTI) [20,21] patterned silicon wafer using a commercial photoresist named GKR 4602 that is used as a mask during the etching processes at STMicroelectronics. Then we will study the impact of using an additional solvent layer of Propylene Glycol Ethyl Ether (PGEE) as a pre-wetting layer.…”

Section: Introductionmentioning

confidence: 99%

Indirect nanoscale characterization of polymer photoresist wetting using ultra-high frequency acoustic waves

Salhab,

Carlier,

Toubal

et al. 2023

Phys. Scr.

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The wetting of surfaces with patterns in the order of a hundred nanometers is often a complex phenomenon to analyze and control. In the semiconductor industry, whether it is during the surface cleaning steps or the deposition of the protective mask (photosensitive liquid resin that is then cross-linked), the conformity of the deposit of the liquid layer on the patterned surface must be perfect or else the functionality of the targeted electronic component will be compromised. Thus, understanding the surface wetting of these liquids allows the implementation of optimized processes. In this paper, we present a method of indirect wetting characterization of a photoresist based on ultra-high frequency (# GHz) acoustic waves. This resin is a commercial product called GKR 4602 (belonging to the KrF series of positive photoresists), which is coated in two different ways: either directly onto the surface of a patterned silicon wafer, or after application of a solvent, Propylene Glycol Ethyl Ether (PGEE), which then acts as a pre-wetting layer. The patterned wafer, playing the role of electrical insulation (Deep Trench Isolation, DTI) are 200 nm wide, deep trenches with a high aspect ratio (> 50). The originality of this paper lies in the validation of the acoustic characterization by direct observation of the wetting of the cross-linked resin. To do so, we used a FIB (Focused Ion Beam) microscope which allowed us to make cuts and capture localized images of the wetting state of the photoresist. Moreover, all the results obtained (resins and patterned silicon surfaces) are directly from the microelectronics industry (STMicroelectronics), showing that our method is fully compatible with an industrial approach.

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Deep Trenches Cleanliness Challenges for CMOS Image Sensors

Cited by 5 publications

References 2 publications

Airborne Molecular Contamination: Mechanism and Consequences on Devices

Airborne Molecular Contamination: Mechanism and Consequences on Devices

Polydimethylsiloxane Micro-Channels Application for the Study of Dynamic Wetting of Nano-Etched Silicon Surfaces Based on Acoustic Characterization Method

Indirect nanoscale characterization of polymer photoresist wetting using ultra-high frequency acoustic waves

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