JPH02170137A - Mim liquid crystal panel - Google Patents

Abstract

PURPOSE:To form thin-film capacitors having high reliability and to improve display contrast by forming the insulating film for the thin-film capacitors by anodic oxidation of tantalum with a prescribed voltage for each of MIM elements. CONSTITUTION:The MIM elements 13 which are supplied with signals by chromium lines 13 are formed on one substrate forming the liquid crystal panel. The tantalum lines 11 and the thin-film capacitors 10 formed by lamination of the tantalum oxide film obtd. by the anodic oxidation of the lines 11 and picture element electrodes 12 consisting of ITO are provided on the element 13. The insulating film of the capacitors 10 is again anodized by the voltage higher than the anodic oxidation voltage of the tantalum at the time of forming the elements 13 and the resistance of the capacitors 10 is higher than the resistance of the elements 13. The thin-film capacitors having the high reliability are, therefore, easily and surely formed and the MIM liquid crystal panel of the stable contrast is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for reliably creating internal capacitance in an MIM liquid crystal panel.

[Prior Art] FIG. 2 shows an enlarged plan view of a pixel portion of an example of a substrate on which MIM elements of a conventional MIM liquid crystal panel are formed. MI from tantalum line 21 with anodized surface
A signal is supplied to the M element 22, further passes through the MIM element 22, and passes through the upper electrode 23 of the MIM element to the pixel electrode 24.
FIG. 5 is a plan view of a conventional MIM liquid crystal panel in which a thin film capacitor is formed. The thin film capacitors 6 are formed by reactively sputtering a tantalum oxide film on the chrome line 67, and further layering the pixel electrode 24.

[Problems to be solved by the invention] 1. In a panel like the one shown in Fig. 2 in which internal capacitance is not built in, pixel signals are not retained sufficiently, resulting in insufficient contrast or uneven contrast within the panel. It was easy.

2. Even if a unidirectional partial capacitor is created, if the insulating film of the thin film capacitor 66 is subjected to reactive scattering as shown in Fig. 3, the resistance value of the insulating film is small, and the Nj pseudo capacitor 36 is created. I couldn't make it effective. Therefore, as in 1, lack of contrast and unevenness of contrast tend to occur within one panel.The present invention aims to solve the above-mentioned problems by the following means.

[Means for Solving the Problems] The MIM liquid crystal panel of the present invention is a liquid crystal panel in which a MIM element is formed on one of the upper and lower substrates, and a thin film capacitor is formed for each pixel on the element forming substrate. The insulating film of the thin film capacitor is formed by anodic oxidation of tantalum, and is characterized in that it is anodized at a higher voltage than the anodic oxidation voltage of tantalum used when forming an MIM element.

[Embodiment] FIG. 1 is a plan view of a pixel portion of a panel showing an embodiment of the present invention. In this example, the thin film capacitor 10 is formed by stacking a tantalum line 11, a tantalum oxide film obtained by anodizing the tantalum line 11, and a pixel electrode TO12. It is the chrome line 14 that supplies the signal to the MIM element 15. When the insulating film of the thin film capacitor 10 is formed by anodic oxidation of tantalum in this manner, a high-resistance, high-quality insulating film can be obtained uniformly over the entire panel. In terms of process, MIM
When manufacturing the element 13 by anodic oxidation, the thin film capacitance 10
An insulating film is made, and the MIM element 16 and the tantalum line 11 are
After separating the tantalum lines, it is reliable and simple to anodize only the tantalum line 110 portion again at a high voltage. The insulation resistance of the thin film capacitor needs to be higher than the resistance of the MIM element. Therefore, it is necessary to perform anodic oxidation at a higher voltage than the MIM element. If the anodic oxidation voltage is doubled, the resistance per unit area will be approximately 700 times higher. 15 is a tantalum line removed by etching.

[Effects of the Invention] With the structure of the present invention, a thin film capacitor can be made with high reliability,
The effect is that it is possible to manufacture an excellent noggle with stable contrast.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a pixel section showing an embodiment of the present invention. FIG. 2 is a plan view of a pixel section showing a conventional embodiment. FIG. 3 is a plan view of a pixel section showing another conventional embodiment. that's all

Claims (1)

[Claims] In a liquid crystal panel in which a MIM element is formed on one of the upper and lower substrates, and a thin film capacitor is formed for each pixel on the element forming substrate, the insulating film of the thin film capacitor is formed by anodizing tantalum, An MIM liquid crystal panel characterized in that it is anodized at a voltage higher than the anodizing voltage used for tantalum when forming an MIM element.