Method to pattern Indium-Tin-Oxide-Films on Glass Substrates
Original Publication Date: 2004-Apr-08
Included in the Prior Art Database: 2004-Apr-08
Disclosed is a method for manufacturing electrodes out of Indium-Tin-Oxide (ITO) for Organic Light Emitting Diodes (OLED), providing a transparent Glass Substrate, coated with ITO material and pattering of the ITO using conventual i-line (365nm wavelength) Photolithography.
Method to pattern Indium -
-Films on Glass Substrates
Films on Glass Substrates
Summary The present publication generally relates to a method for manufacturing Organic Light Emittung Diodes (OLED, Fig.1) and more particularly to a method to pattern the OLED electrodes consisting of Indium-Tin-Oxide (ITO) .
Hole Injection Layer
Hole Mobility Layer
Fig 1: OLED Layer Schematics (source: Schott Spezialglas Mainz)
An OLED electrode is formed by depositing an ITO on a glass substrate, then spin coating and softbaking a positive tone photo resist followed by a masking process using 365nm-UV (Ultra Violet Light)-exposure and developing of the pattern using a standard alkaline developer solution.
However, the ITO electrode has quite a bad reliability due to low adhesion between the ITO and the organic photo resist layer. As a result, the reliability and line width control of the ITO is difficult to control and vastly degraded.
R ESIST EX PO SE
F u ll F ilm (IT O )
RESIST D EVELO P
STR IP R ESIST
R ESIST A PPLY 1
STR IP R ESIST
R E SIST A PPL Y 2
Fig 2: Process Flow Schematics
To solve the adhesion problem an additional process step combination consisting of apply - and strip resist 1 was implemented (FIG:3).
Ø apply of resist 1 => FSI 2100 modified (Fig.2...