Method for monitoring contact hole etching process of TFT substrate

A method for monitoring a contact hole etching process of a thin-film transistor (TFT) substrate, comprising the following steps:

• (1) providing a substrate having a second metal layer and a monitoring machine;
• (2) providing a target value of reflection rate of the substrate having the second metal layer by measuring a reflection rate of the second metal layer to serve as the target value;
• (3) applying a masking operation to patternize the second metal layer for forming a source/drain terminal;
• (4) forming a source/drain insulation layer on the source/drain terminal;
• and
• (5) forming a contact hole in the source/drain insulation layer through etching and simultaneously operating the monitoring machine to solely measure the reflection rate of a bottom of the contact hole, whereby when the reflection rate of the bottom of the contact hole reaches a value between 90%-110% of the target value, the etching operation is stopped.

A method for monitoring a contact hole etching process of a thin-film transistor (TFT) substrate, comprising the following steps:

• (1) providing a substrate having a second metal layer and a monitoring machine;
• (2) providing a target value of reflection rate of the substrate having the second metal layer by measuring a reflection rate of the second metal layer to serve as the target value;
• (3) applying a masking operation to patternize the second metal layer for forming a source/drain terminal;
• (4) forming a source/drain insulation layer on the source/drain terminal;
• and
• (5) forming a contact hole in the source/drain insulation layer through etching and simultaneously operating the monitoring machine to solely measure the reflection rate of a bottom of the contact hole, whereby when the reflection rate of the bottom of the contact hole reaches a value between 90%-110% of the target value, the etching operation is stopped;
• wherein the substrate comprises a glass substrate or a plastic substrate;
• wherein the second metal layer comprises an aluminum layer;
• wherein in step (2), the target value of reflection rate is reflection rate of the aluminum layer of the second metal layer;
• and
• wherein the source/drain insulation layer comprises a silicon nitride layer.