Pixel Structure Manufacturing Using Three Photomasks
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Solution Overview
Problem
The conventional method of manufacturing pixel structures for display devices requires five photomasks, leading to high production costs and increased costs as substrate sizes increase, due to the need for larger photomasks.
Innovation Solution
A method using only three photomasks to form a pixel structure, where the second photomask is used twice to create complementary patterns for the transparent conductive and channel layers, reducing the number of photolithographic processes and photomask requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If five photomasks are used to form the pixel structure according to the conventional method, then the pixel structure can be manufactured with proper electrical connections and transparency, but the production cost increases significantly
Solution Approach 1:
The patent combines the formation of the transparent conductive layer and channel layer into a single photolithography step using one photomask. The photomask is designed with transparent regions for the conductive layer and opaque regions for the channel layer, allowing both layers to be patterned simultaneously from a single mask, thereby reducing the total number of photomasks from five to three
Solution Approach 2:
The second photomask serves multiple functions: it defines both the transparent conductive layer pattern and the channel layer pattern in a single exposure step. This multi-functional use of the photomask eliminates the need for separate photomasks for each layer, reducing overall manufacturing complexity and cost
2Manufacturing precision
If five photomasks are used in the manufacturing process, then complete pixel structure fabrication is achieved, but the number of photomasks and process steps increases
Solution Approach 1:
The patent merges the patterning operations for the transparent conductive layer and channel layer into a single photolithography step. By designing the photomask with specific transparent and opaque regions, both layers are formed simultaneously, reducing the number of separate photomasking steps from five to three
Solution Approach 2:
The photomask is pre-designed with the complete pattern information for both the transparent conductive layer and channel layer. The transparent regions of the mask automatically define the conductive layer pattern while the opaque regions define the channel layer pattern, eliminating the need for subsequent patterning steps
3Area of stationary object
If larger substrate sizes are used to accommodate more devices, then the display device capacity increases, but the photomask size and production cost increase further
Solution Approach 1:
By combining multiple layer patterns into a single photomask design, the patent reduces the total number of large photomasks required. Instead of needing five separate large photomasks for substrate-sized areas, only three photomasks are needed, directly reducing the material cost and complexity associated with large-area photomask fabrication
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces production costs by minimizing the number of photomasks needed, while maintaining compatibility with existing manufacturing processes and ensuring effective electrical connections and transparency in the pixel structure.
Implementation Method 1
using a first photomask to form a third patterned photoresist layer, and using the third patterned photoresist layer as a mask to form a source/drain on a substrate
Data Source
AI summary
A manufacturing method for a pixel structure is provided. The method includes the following steps. A first photomask is used to form a source/drain on a substrate. A second photomask is used twice to form a transparent conductive layer and a channel layer on the substrate respectively. The transparent conductive layer covers a portion of the source/drain and is electrically connected with the same, and the pattern of the transparent conductive layer and the pattern of the channel layer are complementary patterns. Then, a dielectric layer is formed over the substrate to cover the transparent conductive layer and the channel layer. A third photomask is used to form a gate on the dielectric layer.