Fine Pattern Formation via Mask Shifting Exposure
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Solution Overview
Problem
Current light exposure methods struggle to form precise patterns with narrow widths and small intervals, as they are limited by the resolution of existing light exposers, making it difficult to create patterns narrower than 3 μm in liquid crystal displays.
Innovation Solution
The method involves using a photomask with a specific interval ratio of light shielding to light transmission parts, followed by shifting the mask to achieve precise exposure and development, allowing for the formation of patterns with widths and intervals as small as 1 μm by controlling the horizontal distance and position of light shielding and transmission parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a general light exposer is used for pattern formation, then the manufacturing process is simple and cost-effective, but the pattern width and interval are limited to about 3 μm and cannot be made narrower
Solution Approach 1:
The exposure process is divided into multiple sequential exposure steps, each forming a portion of the final fine pattern. The first exposure forms initial patterns with larger pitch, then the mask is shifted and a second exposure forms additional patterns, ultimately creating the fine-pitch pattern structure that cannot be achieved by a single exposure step.
Solution Approach 2:
The invention introduces a temporal dimension to the exposure process by performing multiple exposures at different times with mask shifts. Instead of attempting to form all patterns simultaneously in one exposure step (spatial approach), the method uses sequential exposures with controlled mask positioning to achieve fine pitch patterns that exceed the single-step resolution limit.
2Reliability
If multiple fine branch electrodes are formed to improve response speed and viewing angle, then liquid crystal display performance is enhanced, but the pattern width becomes very narrow making precise formation difficult
Solution Approach 1:
The first exposure step creates preliminary pattern structures that serve as a foundation for the final fine-pitch pattern. These initial patterns are formed with larger dimensions that are within the capability of standard light exposers, and then subsequent mask shifts and exposures refine these into the final fine branch electrode structures.
Solution Approach 2:
The invention changes the exposure parameters by using different mask positions and shift distances between exposure steps. By controlling the mask shift distance to be equal to or less than the pitch of the first pattern, the method achieves variable effective pitch in different regions, enabling formation of fine patterns with widths and intervals of about 1 μm or less.
3Length of moving object
If the pattern width and interval are reduced to about 1 μm, then finer branch electrodes are achieved improving display performance, but standard light exposer resolution is insufficient
Solution Approach 1:
The photomask serves as an intermediary that enables the formation of fine patterns beyond the direct resolution capability of the light exposer. By using a mask with specific pitch and performing multiple exposures with controlled shifts, the mask mediates between the limited exposer resolution and the desired fine pattern dimensions, effectively multiplying the achievable resolution.
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 enables the formation of fine patterns with 1 μm width and interval, overcoming the limitations of standard light exposer resolutions and enabling the creation of display devices with finer branch electrodes, enhancing the response speed and viewing angle of liquid crystal displays.
Implementation Method 1
first exposing the photoresist by using a photomask where an interval ratio of a light shielding part and a light transmission part is 2CD:1CD to 4CD:1CD
Implementation Method 2
by using a photomask where an interval ratio of a light shielding part and a light transmission part is 2CD:1CD to 4CD:1CD
Data Source
AI summary
A method for forming a fine exposure pattern where a width and an interval of the pattern are each 1CD, by first exposing a photoresist by using an exposure mask where an interval ratio of a light shielding part and a light transmission part is 2CD:1CD to 4CD:1CD, and then second exposing the photoresist after the exposure mask is shifted at a predetermined interval, or second exposing the photoresist by using an exposure mask formed at a position where a light transmission part is shifted at a predetermined interval, and developing the photoresist, such that it is possible to form a display device having a pixel electrode including a plurality of fine branch electrodes having a smaller width and interval than a resolution of an exposure apparatus.