The Main Factors Driving The Application Of Various Gases In The Display

- Jul 30, 2018 -

The main factors driving the use of gases in display manufacturing include PECVD (plasma enhanced chemical vapor deposition), which accounts for 75% of ESG consumption, while dry etching promotes the use of helium. The production of LTPS and MO transistors has driven the use of nitrous oxide. The use of ESG in the production of MO transistors is different from that shown in Figure 4: nitrous oxide accounts for 63% of gas consumption, nitrogen trifluoride accounts for 26%, silane accounts for 7%, and sulfur hexafluoride and ammonia account for about 4%. . Laser gas is used not only for photolithography, but also for excimer laser annealing applications in LTPS.

Silane: SiH4 is one of the most critical gases in the manufacture of display screens. It is used in combination with ammonia (NH3) to form a silicon nitride layer for a-Si transistors. It is used in combination with nitrogen (N2) to form LTPS transistors. The pre-excimer laser anneals a-Si or, in combination with nitrous oxide (N2O), forms a silicon oxide layer of the MO transistor.

Nitrogen trifluoride: From the consumption and use of a-Si and LTPS display production, NF3 is the single most used electronic material in a-Si and LTPS display production, and in MO production, its use The amount is not as good as N2O. NF3 is used to clean the PECVD chamber. For this gas, scalability is required to establish the cost advantages required in a highly competitive market.

Nitrous oxide: Both LTPS and MO display are used in production. From the consumption and use of MO production, N2O has surpassed NF3 to become the most used electronic material in MO production. N2O is a regional, localized product that, due to its low cost, cannot be used in long supply chains with high logistics costs. The average per square meter of plain glass weighs about 2 kg, and generally requires 240 tons of N2O per month to produce a 120K 8.5 MO display. The largest N2O compressed gas trailer can only provide 6 tons of N2O at a time, which is costly and risky for MO production.

Nitrogen: A typical large display plant can have nitrogen requirements of up to 50,000 Nm3/hour, so field generators (such as Linde SPECTRA-N® 50,000) are a cost-effective solution that displays compared to conventional nitrogen plants. CO2 (carbon dioxide) emissions from screen manufacturing are reduced by 8%.

Helium: Helium is used to cool the glass during and after the process. Since helium is a non-renewable gas, manufacturers are studying reducing the use of helium due to their cost and availability.