Photoluminescent Overlay Mark Structure for Precise Alignment Detection
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in accurately measuring overlay errors due to asymmetric shapes of measurement structures, necessitating a more precise method for overlay mark detection.
Innovation Solution
A semiconductor structure is developed with a photoluminescent material, such as rhodamine or fluorescent polyimide, integrated into the scribe line region to form a patterned mask layer, allowing for precise alignment detection through optical signals converted to electrical signals, and a system is employed to facilitate this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement structures are used for overlay error detection, then the manufacturing process is simple, but the measurement precision is insufficient due to asymmetric shapes and detection limitations
Solution Approach 1:
The patent employs photoluminescent materials that emit light at different wavelengths or intensities based on their orientation and position. The overlay mark structure utilizes materials with distinct photoluminescent characteristics that change based on the alignment state, enabling precise overlay error detection through optical signal variations rather than relying on asymmetric geometric shapes
Solution Approach 2:
The overlay mark is constructed using composite materials including photoluminescent materials embedded in a matrix material. This composite structure provides both the mechanical stability needed for manufacturing and the optical properties required for precise alignment detection, resolving the contradiction between structural simplicity and measurement precision
2Manufacturing precision
If photoluminescent materials are integrated into the overlay mark structure, then alignment detection precision is improved, but the manufacturing process complexity increases
Solution Approach 1:
The photoluminescent materials are incorporated into the overlay mark structure during the initial formation process, before subsequent lithography and patterning steps. This preliminary integration ensures that the optical detection capability is established early, simplifying later manufacturing steps while maintaining high alignment precision
Solution Approach 2:
The overlay mark structure serves multiple functions: it provides mechanical support through the matrix material, enables optical detection through photoluminescent materials, and facilitates alignment measurement through its geometric configuration. This multi-functionality reduces the need for separate components, thereby simplifying the overall manufacturing process while achieving high precision
3Measurement precision
If asymmetric measurement structures are used, then the manufacturing process is straightforward, but the detection accuracy deteriorates due to shape asymmetries
Solution Approach 1:
Instead of relying on asymmetric geometric shapes for detection, the patent uses photoluminescent materials whose optical emission characteristics change based on orientation and position. This approach eliminates the need for complex asymmetric structures while achieving high detection accuracy through wavelength or intensity variations in the emitted light
Solution Approach 2:
The patent replaces mechanical/geometric detection methods (which require precise asymmetric shapes) with optical detection methods using photoluminescent materials. This substitution transitions from a mechanically complex system to an optically simpler system that achieves the same measurement goal with easier manufacturing
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
Enables precise alignment of patterns by overcoming detection limitations, ensuring accurate overlay measurements even with varying layer thicknesses and asymmetries, enhancing manufacturing precision.
Implementation Method 1
forming a first photoluminescent layer over the first layer in the scribe line region
Implementation Method 2
converting the second optical signal to a first electrical signal
Data Source
AI summary
The present disclosure provides a semiconductor structure, a method of manufacturing the semiconductor structure and a system for manufacturing the semiconductor structure. The method includes several operations. A substrate including a device region and a scribe line region is provided. A first layer is formed over the substrate. A first photoluminescent layer is formed over the first layer in the scribe line region. The first layer and the first photoluminescent layer are patterned to form a first pattern in the scribe line region. A first patterned mask layer is formed over a second layer. An alignment of the first patterned mask layer with the first pattern is detected. A pattern of the first patterned mask layer is transferred to the second layer to form a second pattern in the scribe line region.