Showing posts with label NCD. Show all posts
Showing posts with label NCD. Show all posts

Friday, July 2, 2021

Future foldable and flexible Display with NCD’s ALD encapsulation technology

In the global market of smart phones, competition on mobile’s form factors has been an important issue since foldable smart phones had launched following cured ones. Samsung electronics applied in-folding form factor to Galaxy Fold and Galaxy Z Flip, and Huawei used out-folding form factor to Mate X. New two or three folding form factor has been unveiling to the public beyond in-folding and out folding displays.

Flexible displays consist of Thin Film Transistor (TFT), Organic Light Emission Diode (OLED) and multi encapsulation layers. Generally organic and inorganic laminated layers is used for foldable displays and PECVD has applied to deposit inorganic materials.

Basically, Inorganic layers is lack of brittleness then their encapsulation property is degraded with continuous mechanical stress. ALD method for TFE was considered instead of PECVD due to their excellent encapsulation characteristics with thicknesses of few tens of nanometers. The reliability of the tool blocked applying to production at that time.

But because of the superior encapsulation property using ALD, many universities, institutes as well as display companies have been developing ALD inorganic layers for flexible displays and evaluating hundreds of thousand times folding test considering actual use recently.

LucidaTM GD Series ALD


The customer which has NCD’s Lucida GD Series ALD, measured folding test on flexible displays with inorganic layers using ALD instead of using PECVD and showed great performance under actual display operation. The 5.85 inch AMOLED display panels for in-folding and out-folding consisted of encapsulation structure of 30nm Al2O3 ALD/ 8㎛-Polymer/ 30nm Al2O3 and was tested in-folding and out-folding evaluation of 200,000 times with bending radius of 2R under light status after the 1st reliability test of RA 60℃/90% for 500hr. There were no dark spots on the panels after finishing the folding measurement. The 2nd reliability test of RA 60℃/90% for 48hr followed folding evaluation and then the TFE status was examined without any cracks.


Using NCD’s large area batch ALD system for foldable phones could obtain superior encapsulation property and flexibility with very thin inorganic layers to current ones using PECVD as well as provide great productivity because the batch tool can process lots of panels at one time.

Then NCD really looks forward to applying its large area batch ALD technology to encapsulation of future flexible display with in/out-folding and very small bending radius because of having solved the previous issues without both reliability and productivity that the reason is why ALD equipment didn’t apply for mass production of flexible display.

Friday, June 5, 2020

Thermal ALD IGZO Properties for LTPO TFTs by NCD

 
LTPS TFTs have been applied to most of the display for smart phones which consume most of the power for their operating because they have high electron mobility showing fast response time even if they have higher power consumption than that of IGZO TFTs,

Recently applications of LTPO (Low Temperature Polycrystalline Oxide) TFTs have been increasing to save the powder consumption of mobile and wearable devices. LTPO TFTs are the device combining LTPS TFTs with fast speed and Oxide TFTs with low leakage current. That is, switching uses Oxide TFTs because of being on/off the light fast and operating uses LTPS TFTs due to changing display rapidly with control of the mount of light.

A lot of smart device manufacturers including Apple are using or will use LTPO displays for their latest smart watches because their power consumption can decrease ~40%. Also, many manufacturers like Samsung and Apple have actively been developing their high-end smart phones equipped with the LTPO displays to make the power usage optimized.



General LTPO Structure and Properties

IGZO thin films used for Oxide TFTs have typically been processed by sputtering, but this method continuously has been showing lots of issues such as their bad thickness and composition uniformity, degradation of the physical and electrical properties due to plasma damage and the stability problem of targets. However using thermal ALD-IGZO, it is possible to deposit high quality thin films because of no plasma damage in process, low process temperature, and atomic scale controllability of thickness and composition.


Thermal ALD IGZO Properties

It is possible to get exact target atomic compositions of IGZO thin films by controlling the ratios of ALD cycle of respective sources in thermal ALD. Therefore this method could show the superior device properties to that by sputtering because it enables to control easily and exactly the most suitable atomic composition for the respective device structure of customers.

NCD has been developing high throughput batch IGZO-ALD system with its creative technology enabled to adapt the target atomic composition for respective devices. NCD could provide the competitiveness of excellent quality and the high productivity for LTPO TFTs including IGZO thin films using Lucida GD Series ALD which could process many and large area substrates at once.


NCD’s LucidaTM GD Series ALD

Source: http://www.ncdtech.co.kr/2018/bbs/board.php?bo_table=eng_board_05&wr_id=51

Thursday, March 26, 2020

NCD supplied two Lucida M300 ALD systems for R&D to KANC

NCD has recently supplied 2 Lucida M300PL ALD systems to KANC. Lucida M300PL-O is the equipment for oxide deposition with Ozone and Plasma process, and Lucida M300PL-M is that for metal deposition with Plasma process.

These wafer process equipment have the specification below

1) System: Lucida M300PL-O, Lucida M300PL-M

2) Substrate: Wafer 300mm

3) Deposition Materials:

- Lucida M300PL-O: Al2O3, TiO2, ZrO2, ZnO, HfO2, Ta2O5

- Lucida M300PL-M: Co. Ru, W, Ir, TiN, TaN

KANC, which is the most prestigious institute of Korea on nanotechnology, is using Lucida M300PL to investigate cutting edge semiconductor development and promising applications in MEMS and IoT. So it will be expected that these systems will contribute very much to the development of high-end nanotechnology.

NCD will do best to be the best ALD equipment company with continuous R&D efforts. 
 
 
 
< Lucida M300PL ALD >

Wednesday, January 15, 2020

Metal mask coating by ALD for reliable plasma process in PECVD

The PECVD method with metal masks has, in general, been used to deposit inorganic layers like SiNx and SiO2 for manufacturing LCD and OLED displays.

However, this plasma process has severe problems like plasma arcing or particle generation due to instability of electrical isolation between the metal mask and the showerhead as an RF electrode. Therefore it is required to deposit dielectric materials such as Al2O3, Y2O3, TiO2, MgO, ZrO2, etc. on the metal mask to prevent plasma damage.

Typically, the dielectric layer is coated by a sputtering method, also known as physical vapor deposition (PVD). However, this method is difficult to coat the metal mask uniformly with large area and complex structure as well as it has the disadvantage of requiring a thick deposition of several µm and multiple processes.

To obtain excellent electrical isolation properties of metal masks in the PECVD process, the atomic layer deposition (ALD) of Al2O3 thin film might be the best solution which enables getting uniform deposition on them with large area and complex structure. 

ALD Al2O3 layers could give them remarkable electric isolation and great protection, even if the thickness is less than one ㎛. When 50nm ~ 200nm layers of Al2O3 deposited by NCD large-area demo tool on metal masks were applied to the PECVD process, there was no issues like plasma arcing or damage. 

Images of metal mask coated by ALD with Al2O3 a) before (b) after

In fact, even though ALD Al2O3 has lots of advantages, the end customer has to consider of low throughput using general large-area ALD equipment. However, NCD’s Lucida GD Series for large-area ALD applications might be the most suitable equipment with superb productivity to provide superior protective layers to the metal masks from plasma issues in the PECVD process.

NCD has steadily developed large area and high throughput ALD equipment and technology. The applications for display, solar cell, and semiconductor fields have been already commercialized, and also NCD has worked hard to find use in special markets like excellent plasma protective coating on metal masks. NCD will aggressively respond to the development and then supply of ALD equipment, which customers would need for various industries in the future.



LucidaTM ALD system for metal mask coating.

Wednesday, November 13, 2019

Improvement of the quantum efficiency of micro LED by ALD passivation

Micro LED has been interested in the next generation display and been actively developing at many electronics manufactures and institutes for applications of AR/VR, wearable device and extra-large display as a core factor of the forth industry. Also it is evaluated to have superior properties to LED as well as OLED with low power consumption, excellent brightness, greater contrast, flexibility and reliability.

Micro LED of less than 10 µm size is required for displays needed high pixel per inch (PPI) but the quantum efficiency drop would occur by sidewall effect in the manufacturing process. Looking at the reason in detail, micro LED chips require separation of them by dry etching process and the sidewall effect reducing external and internal quantum efficiency happens not to optimize extraction of light by chemical contaminations and structural damages during the etching process.

ALD passivation on the sidewall of Micro LED after dry etching process

The passivation of sidewall by atomic layer deposition recover and remove the plasma damage by dry etching so that the quantum efficiency could be increased and also the ratio of improvement could increase as small as the size of micro LED.

Specially, the interest of productive ALD equipment has been gradually increased because of the excellent dielectric passivation by ALD Al2O3 thin films expecting to improve quantum efficiency.

NCD has been developing wafer based high throughput batch ALD system continuously enable to form high quality oxide passivation to improve the quantum efficiency of micro LED. By introduction of the system in production of micro LED, it could be expected to guarantee the productivity, high quality and performance reliability of high resolution micro LEDs for applications of AR/VR, flexible and wearable devices and extra-large displays.  

NCD Si wafer based batch ALD cluster system