EUV Photomask Scribe Lane Dummy Patterns for Light Control
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Solution Overview
Problem
Current EUV photomasks used in semiconductor manufacturing are costly, time-consuming, and prone to defects due to unnecessary scattering of reflected EUV light, which affects the main area during the exposure process.
Innovation Solution
The design of an EUV photomask with a reflective multilayer film and an absorption pattern, including dummy patterns in the scribe lane area, which controls the reflection of EUV light to ensure it exceeds the threshold dose only in the intended areas, thereby reducing unwanted light exposure on the main area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the scribe lane area is designed to reflect EUV light for manufacturing purposes, then the photomask can be used for scribe lane patterning, but the reflected EUV light is scattered and causes unwanted exposure in the main area
Solution Approach 1:
The scribe lane area is divided into multiple lanes (first lane, second lane, third lane, fourth lane) with each lane containing multiple sub-lanes. This segmentation allows precise control of light reflection in different regions, enabling the scribe lane patterning function while containing scattered light within designated areas through the use of dummy patterns in specific sub-lanes.
Solution Approach 2:
Different regions of the scribe lane area are assigned different functions: some sub-lanes contain dummy patterns that reflect light locally, while other sub-lanes are designed to absorb or block scattered light. This local differentiation ensures that the main area is protected from unwanted exposure while maintaining scribe lane patterning capability.
2Manufacturing precision
If dummy patterns are added to control light reflection in scribe lane, then light exposure control is improved, but the photomask design and manufacturing complexity increases
Solution Approach 1:
The dummy patterns are segmented into specific sub-lanes (first sub-lane, second sub-lane, etc.) within the scribe lane area. This segmentation allows the dummy patterns to be positioned precisely where needed to control light reflection, improving exposure control without requiring dummy patterns throughout the entire photomask structure.
Solution Approach 2:
Instead of adding dummy patterns across the entire photomask, the invention applies dummy patterns only in specific sub-lanes where light reflection control is needed. This partial application achieves the necessary exposure control while minimizing the increase in overall photomask complexity.
3Reliability
If multiple lanes with dummy patterns are implemented, then light reflection control is enhanced, but the manufacturing time and cost increase
Solution Approach 1:
The scribe lane area is segmented into four lanes with specific dummy pattern arrangements, which provides reliable light reflection control for scribe lane patterning. This segmented approach ensures that each lane can be optimized independently for its specific function, improving overall reliability without requiring a complete redesign of the entire photomask.
Solution Approach 2:
The dummy patterns serve multiple functions: they control light reflection in the scribe lane area, prevent unwanted exposure in the main area, and enable reliable scribe lane patterning. This multi-functionality reduces the need for additional separate structures, thereby limiting the increase in manufacturing time and cost.
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 allows for the efficient and defect-free manufacturing of EUV photomasks, enabling quicker and more cost-effective production with reduced unwanted light exposure on the main area, thus improving the semiconductor substrate patterning process.
Implementation Method 1
the scribe lane area surrounding the main area and reflecting EUV light
Implementation Method 2
an absorption pattern on the reflective multilayer film
Data Source
AI summary
An EUV photomask having a main area and a scribe lane area and reflecting EUV light includes a reflective multilayer film and an absorption pattern, wherein the scribe lane area includes first and second lanes, wherein the first lane includes first and second sub-lanes extending in the same direction as an extending direction of the first lane, wherein the first sub-lane includes a first dummy pattern that is a portion of the absorption pattern, and the second sub-lane includes a second dummy pattern that is a portion of the absorption pattern, and when EUV light that is not absorbed by the first and second dummy patterns and is reflected by the reflective multilayer film is irradiated at least twice by overlapping a negative tone photoresist, an amount of light exceeds a threshold dose of light in the negative tone photoresist corresponding to the first lane.