Liquid Crystal Display Bottom Substrate Mask Reduction
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Solution Overview
Problem
The manufacturing process of thin film transistor arrays in liquid crystal display devices requires five masks for photolithography and etching, leading to high costs and alignment errors, which are not effectively reduced.
Innovation Solution
A method that uses only four masks by aligning the patterns of the first metal layer and semiconductor layer, allowing the first metal layer to serve as a mask for subsequent processes, thereby reducing the number of masks needed and aligning errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If five masks are used for photolithography and etching processes, then the components of the thin film transistor array can be precisely defined, but the manufacturing cost increases and the process complexity increases
Solution Approach 1:
The patent merges the functions of five separate masks into four masks by making the first metal layer pattern and semiconductor layer pattern identical. This allows the first photolithography process to simultaneously define both the first metal layer and the semiconductor layer, eliminating the need for a separate second mask while maintaining precise pattern definition for all thin film transistor array components.
Solution Approach 2:
The first mask serves multiple functions by defining both the first metal layer pattern and the semiconductor layer pattern. This multi-functional mask approach reduces the total number of masks required while ensuring that all subsequent layers (second metal layer, planar layer, passivation layer, transparent conductive layer) can be accurately positioned relative to the initially defined patterns.
2Manufacturing precision
If five masks are used for photolithography and etching processes, then the components of the thin film transistor array can be defined, but the manufacturing cost becomes more expensive
Solution Approach 1:
The patent combines the patterning functions for the first metal layer and semiconductor layer into a single photolithography process using one mask. This merger reduces the total mask count from five to four, directly lowering manufacturing costs while maintaining the necessary pattern definition quality for thin film transistor array components.
Solution Approach 2:
The patent discards the need for a separate second mask by utilizing the first metal layer pattern as a reference for semiconductor layer formation. This eliminates redundant mask manufacturing costs while ensuring pattern alignment through the shared first mask definition.
3Productivity
If five masks are used for photolithography and etching processes, then all layers can be patterned, but the mask alignment error increases
Solution Approach 1:
The patent merges the patterning of the first metal layer and semiconductor layer into a single photolithography step using one mask. This eliminates the cumulative alignment errors that would result from using two separate masks, as only one mask alignment operation is required. The subsequent layers can be accurately positioned relative to this single reference pattern.
Data Source
AI summary
A method for manufacturing a bottom substrate of a liquid crystal display device is disclosed. The method is achieved by proceeding two lithography processes cycles with a single mask. Therefore, the method of the present invention can manufacture a bottom substrate through five lithography processes cycles with only four masks. Thus, the cost of a liquid crystal display device can be reduced due to the absence of the manufacturing cost of one mask.