Comparison of copper electroplating, copper wet etching and linear sweep voltammetry as techniques to investigate the porosity of atomic layer deposited Al2O3

Vanhaverbeke, Celine; Cauwe, Maarten; Stockman, A.; Beeck, Maaike Op de; Smet, Herbert De

doi:10.1016/j.tsf.2019.137424

Cited by 9 publications

(17 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests that the corrosion holes may be attributed to local defects of the barrier since particle contamination could not be avoided during sample preparation. Another possible reason is that there were a few areas without good nucleation of the ALD Al 2 O 3 layer, which resulted in minor voids in the ALD Al 2 O 3 layer, which was also reported by Zhang et al and Klumbies et al [24,46,47]. We calculated the density of the corrosion holes on the copper ( Figure 5) protected by ALD Al 2 O 3 and ALD-3.…”

Section: Optical Microscope Observationmentioning

confidence: 61%

See 1 more Smart Citation

Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Cauwe

Yang

et al. 2019

Coatings

View full text Add to dashboard Cite

Long-term packaging of miniaturized, flexible implantable medical devices is essential for the next generation of medical devices. Polymer materials that are biocompatible and flexible have attracted extensive interest for the packaging of implantable medical devices, however realizing these devices with long-term hermeticity up to several years remains a great challenge. Here, polyimide (PI) based hermetic encapsulation was greatly improved by atomic layer deposition (ALD) of a nanoscale-thin, biocompatible sandwich stack of HfO2/Al2O3/HfO2 (ALD-3) between two polyimide layers. A thin copper film covered with a PI/ALD-3/PI barrier maintained excellent electrochemical performance over 1028 days (2.8 years) during acceleration tests at 60 °C in phosphate buffered saline solution (PBS). This stability is equivalent to approximately 14 years at 37 °C. The coatings were monitored in situ through electrochemical impedance spectroscopy (EIS), were inspected by microscope, and were further analyzed using equivalent circuit modeling. The failure mode of ALD Al2O3, ALD-3, and PI soaking in PBS is discussed. Encapsulation using ultrathin ALD-3 combined with PI for the packaging of implantable medical devices is robust at the acceleration temperature condition for more than 2.8 years, showing that it has great potential as reliable packaging for long-term implantable devices.

show abstract

Section: Optical Microscope Observationmentioning

confidence: 61%

“…The most extensive research is performed on Al 2 O 3 layers thanks to its low moisture permeability as well as its excellent thermal and mechanical properties [13,[22][23][24]. For example, single-layered 20 nm ALD Al 2 O 3 possesses superior WVTR in the order of 10 −3 g•m −2 •day −1 in a few days [25].…”

Section: Introductionmentioning

confidence: 99%

Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Cauwe

Yang

et al. 2019

Coatings

View full text Add to dashboard Cite

show abstract

“…Nevertheless, to confirm the presence of defects, one ALD-coated IDC was applied to a 5 V DC voltage for 24 hours. Techniques such as DC leakage measurement and linear sweep voltammetry have been reported as methods for evaluating ALD layers, however, their use could result in further degradation and opening of the defects [9], [13]. In this work, our purpose was merely to be able to confirm the presence of defects in the layer.…”

Section: B Discussionmentioning

confidence: 99%

Long-term Encapsulation of Platinum Metallization Using a HfO₂ ALD - PDMS Bilayer for Non-hermetic Active Implants

Nanbakhsh

Ritasalo

Serdijn

et al. 2020

2020 IEEE 70th Electronic Components and Technology Conference (ECTC)

View full text Add to dashboard Cite

In this work, we investigate the insulating performance of an atomic layer deposited (ALD) HfO2-polymer bilayer for platinum (Pt) metallization. As test vehicles, Pt interdigitated comb structures (IDC) were designed and fabricated on SiO2/Si substrates. The IDCs were first coated with a 100 nm thin HfO2 ALD layer. A group of samples was further encapsulated with a low-viscosity biocompatible polydimethylsiloxane (PDMS) which resulted in an HFO2-PDMS bilayer. All samples were soaked in phosphate buffered saline for 450 days at room temperature. Evaluation of the coatings included monthly optical inspection and electrochemical impedance spectrometry. For ALD-only coated IDC structures, impedance results right after submersion in saline indicated the presence of defects in the layer. Long-term impedance recordings showed a slight drop, indicating water ingress through the defects, further exposing the metal to saline. For the HfO2-PDMS encapsulated samples, on the other hand, stable impedance results were recorded over the duration of the soak study. This suggests the excellent properties of low-viscosity PDMS both in filling the defects of the ALD layer and in maintaining a long-term underwater adhesion to HfO2. The results from this investigation, therefore, propose a new encapsulation method based on HfO2-PDMS bilayer for long-term packaging of active implants incorporating Pt metallization.

show abstract

“…ALD is a technique for ultrathin film deposition, enabling a very high control of the film composition, step coverage, and thickness, due to the advantages of the sequential, self-limiting reactions in an ALD process. This results in a thin conformal layer with extremely low pinhole density [15][16][17][18]. Due to its reliable deposition process and very low water vapor transmission rate (WVTR), Al 2 O 3 is the most readily studied thin film used for corrosion protection of steel and moisture/oxygen diffusion protection in organic light-emitting diodes (OLED) [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…Although an ALD layer is theoretically pin-hole free, very small pore defects are observed which can lead to leakage paths in the barrier layers [27]. Porosity inspection of the ALD Al 2 O 3 by Cu electroplating or Cu wet etching are practical methods to evaluate the quality of the ALD layers [18]. Monitoring the changes in the thickness or roughness of the ALD Al 2 O 3 layer when the layer is soaked in an aqueous environment enables us to study the dissolution of Al 2 O 3 [23,25].…”

Section: Introductionmentioning

confidence: 99%

Accelerated Hermeticity Testing of Biocompatible Moisture Barriers Used for the Encapsulation of Implantable Medical Devices

Cauwe

Mader

et al. 2019

Coatings

Self Cite

View full text Add to dashboard Cite

Barrier layers for the long-term encapsulation of implantable medical devices play a crucial role in the devices’ performance and reliability. Typically, to understand the stability and predict the lifetime of barriers (therefore, the implantable devices), the device is subjected to accelerated testing at higher temperatures compared to its service parameters. Nevertheless, at high temperatures, reaction and degradation mechanisms might be different, resulting in false accelerated test results. In this study, the maximum valid temperatures for the accelerated testing of two barrier layers were investigated: atomic layer deposited (ALD) Al2O3 and stacked ALD HfO2/Al2O3/HfO2, hereinafter referred to as ALD-3. The in-house developed standard barrier performance test is based on continuous electrical resistance monitoring and microscopic inspection of Cu patterns covered with the barrier and immersed in phosphate buffered saline (PBS) at temperatures up to 95 °C. The results demonstrate the valid temperature window to perform temperature acceleration tests. In addition, the optimized ALD layer in combination with polyimide (polyimide/ALD-3/polyimide) works as effective barrier at 60 °C for 1215 days, suggesting the potential applicability to the encapsulation of long-term implants.

show abstract

Comparison of copper electroplating, copper wet etching and linear sweep voltammetry as techniques to investigate the porosity of atomic layer deposited Al2O3

Cited by 9 publications

References 32 publications

Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Long-term Encapsulation of Platinum Metallization Using a HfO₂ ALD - PDMS Bilayer for Non-hermetic Active Implants

Accelerated Hermeticity Testing of Biocompatible Moisture Barriers Used for the Encapsulation of Implantable Medical Devices

Contact Info

Product

Resources

About

Comparison of copper electroplating, copper wet etching and linear sweep voltammetry as techniques to investigate the porosity of atomic layer deposited Al2O3

Cited by 9 publications

References 32 publications

Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Ultra-Long-Term Reliable Encapsulation Using an Atomic Layer Deposited HfO2/Al2O3/HfO2 Triple-Interlayer for Biomedical Implants

Long-term Encapsulation of Platinum Metallization Using a HfO2 ALD - PDMS Bilayer for Non-hermetic Active Implants

Accelerated Hermeticity Testing of Biocompatible Moisture Barriers Used for the Encapsulation of Implantable Medical Devices

Contact Info

Product

Resources

About

Long-term Encapsulation of Platinum Metallization Using a HfO₂ ALD - PDMS Bilayer for Non-hermetic Active Implants