Test Structure for Sheet Resistance Measurement
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Solution Overview
Problem
Existing test structures for measuring sheet resistance of pixel electrodes on array substrates are prone to errors due to over-etching during the etching process, leading to inaccurate measurements.
Innovation Solution
A test structure with an elongated measuring pattern, where the width of the measuring pattern is significantly greater than its length, and includes a transparent conductive material like indium tin oxide, is used to reduce measurement errors when the pixel electrode layer is overly etched, while maintaining a fixed length to prevent unnecessary area increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional TEG pattern is used for measuring sheet resistance, then the measurement process is simple, but the measurement accuracy deteriorates due to over-etching during the pixel electrode etching process
Solution Approach 1:
The test structure is divided into distinct functional segments: terminal parts for electrical connection, an extending part for current injection, and a measuring part for voltage measurement. This segmentation allows each part to be optimized independently, with the measuring part using a wide-short pattern that is insensitive to etching while the terminal parts maintain standard connection geometry.
Solution Approach 2:
The measuring part transitions from a traditional square or rectangular pattern to a wide-short pattern where the width is significantly larger than the length. This dimensional change creates a geometry where the measurement becomes primarily dependent on the width dimension, which is protected from etching effects, rather than the length dimension which extends into the etched region.
2Measurement precision
If the measuring pattern width is increased to reduce measurement error, then the measurement accuracy improves, but the test region area increases unnecessarily
Solution Approach 1:
The test structure implements local quality by applying the wide-short pattern geometry specifically to the measuring part, while the terminal parts and extending parts maintain conventional dimensions. This localized application of the wide geometry ensures that the area increase is confined to only the region necessary for accurate measurement, rather than expanding the entire test structure.
Solution Approach 2:
The measuring part is merged with the extending part such that the wide measuring pattern is superimposed on the extending structure. This merging allows the measuring function to benefit from the extended current path while maintaining a compact overall footprint, as the wide pattern area is efficiently utilized for both measurement and structural support.
Data Source
AI summary
A test structure includes a terminal pattern, a first extending part, a second extending part and a measuring part. The terminal pattern includes a first terminal part, a second terminal part, a third terminal part and a fourth terminal part sequentially disposed and spaced apart from each other in a first direction. The first extending part is connected to the first terminal part and the second terminal part. The first extending part extends in a second direction crossing the first direction. The second extending part is connected to the third terminal part and the fourth terminal part. The second extending part extends in the second direction. The measuring part partially overlaps the first extending part and the second extending part.