LCD Passivation and Pixel Electrode Formation via Single Half Tone Mask
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Solution Overview
Problem
The existing manufacturing methods for LCD devices with integrated touch sensors require multiple masks, leading to increased manufacturing costs and time, and result in defective contacts due to the loss of pixel electrodes in pad areas, affecting the display and testing of the panels.
Innovation Solution
A method that simultaneously forms a passivation layer and pixel electrode using a single half tone mask, preventing disconnection in pad areas by employing a bridge layer of transparent or opaque conductive materials to connect pixel pads and bars, thereby enhancing contact performance and reducing the number of masks needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple masks are used to form passivation layer and pixel electrode separately, then manufacturing precision is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent combines the formation of the passivation layer and pixel electrode into a single mask process. The mask pattern includes both the passivation layer formation region and the pixel electrode formation region, allowing both layers to be created simultaneously in one exposure and development cycle, thereby reducing manufacturing time while maintaining pattern precision
Solution Approach 2:
The single mask serves multiple functions: it defines both the passivation layer boundaries and the pixel electrode pattern. This multi-functional mask design eliminates the need for separate masks for each layer, reducing the total number of masking steps without compromising the precision of either layer formation
2Manufacturing precision
If multiple masks are used for forming passivation layer and pixel electrode, then pattern precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the mask processes for the passivation layer and pixel electrode into a single masking operation. This consolidation reduces the total number of masks required, lowering material costs and reducing the cumulative cost of multiple alignment and processing steps
Solution Approach 2:
The mask design provides universal functionality by simultaneously defining both the passivation layer and pixel electrode patterns. This single mask approach eliminates the need for purchasing and managing multiple specialized masks, reducing overall manufacturing costs while maintaining the precision needed for both structures
3Productivity
If lift-off process is used to form pixel electrode, then manufacturing efficiency is improved, but pixel electrode loss occurs in pad area
Solution Approach 1:
The patent performs preliminary action by forming the pixel electrode directly in the desired final position using the half-tone mask, avoiding the lift-off process entirely. The pixel electrode material is deposited only where needed through the semi-transparent mask regions, ensuring proper formation without subsequent removal steps that could cause material loss
Solution Approach 2:
The patent extracts the problematic lift-off step from the manufacturing process. By using the half-tone mask to directly define the pixel electrode pattern during deposition, the process eliminates the lift-off operation that was causing pixel electrode loss in the pad area, thereby improving contact reliability while maintaining efficiency
4Productivity
If single mask process is used to simultaneously form passivation layer and pixel electrode, then manufacturing efficiency is improved, but pattern precision may deteriorate
Solution Approach 1:
The mask employs local quality variations through different transparency regions: full-tone areas for passivation layer formation, half-tone areas for pixel electrode formation, and clear areas for contact holes. This spatial variation in mask properties allows precise control over material deposition in different regions simultaneously, maintaining high pattern precision while improving manufacturing efficiency
Solution Approach 2:
The mask utilizes optical density variations (analogous to color changes) with different transparency levels. The half-tone regions have intermediate optical density that allows partial light transmission, enabling precise control of photoresist exposure and subsequent material deposition. This optical property variation allows the single mask to achieve the precision normally requiring multiple masks with different transparency characteristics
Data Source
AI summary
Disclosed are an LCD device and a method of manufacturing the same, in which a passivation layer and a pixel electrode are simultaneously formed by a single mask process using a half tone mask, and thus, manufacturing efficiency increases, and a defective contact due to loss of the pixel electrode can be prevented in a pad area. The LCD device includes a pad part including a pad area and a contact area. The LCD device includes a pixel pad formed in the pad area, a pixel bar formed in the contact area, and a bridge layer contacting the pixel pad with the pixel bar. The bridge layer is formed as a single layer or multi layers, and formed of one or more of a transparent conductive material and an opaque conductive material.