Overlay Mark Structure Using Fluorescence for Precise Alignment
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Solution Overview
Problem
The semiconductor industry faces challenges in accurately measuring overlay errors in lithography operations due to unclear optical images between current and pre-layers of overlay mark structures, making precise alignment difficult.
Innovation Solution
A semiconductor device structure is developed that includes a substrate with a light-emitting feature emitting fluorescence, which improves contrast between overlay mark structures in optical images, allowing for more accurate calculation of overlay errors by using patterns with different transmittances to the emitted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional overlay mark structures are used without light-emitting features, then the device structure remains simple, but the optical images become unclear and overlay error measurement precision deteriorates
Solution Approach 1:
A light-emitting feature is introduced as an intermediary element between the substrate and the overlay mark structures. This light-emitting feature emits light that passes through the overlay mark structures, creating enhanced optical images that improve measurement precision without fundamentally changing the overlay mark structure design
Solution Approach 2:
The optical properties of the overlay mark structures are enhanced by changing the parameter of light emission. The light-emitting feature emits light at specific wavelengths, and the overlay mark structures are designed with specific transmittances to these wavelengths, creating contrast that improves measurement precision
2Measurement precision
If overlay mark structures with uniform transmittance are used, then the manufacturing process is simple, but the contrast between current layer and pre-layer in optical images is poor
Solution Approach 1:
The overlay mark structures are designed with different local qualities in terms of light transmittance. The first overlay mark structure has a first transmittance to light of a first wavelength, while the second overlay mark structure has a second transmittance to light of a second wavelength. This local differentiation in transmittance properties creates contrast in the optical images, improving measurement precision while maintaining manufacturability through standard lithography processes
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
The use of fluorescence-emitting features enhances the visibility of overlay mark structures, enabling more precise alignment and accurate measurement of overlay errors, thereby improving the precision of lithography operations.
Implementation Method 1
The light emitting feature can be configured to emit fluorescence. The fluorescence can improve the contrast between a current layer and a pre-layer of an overlay mark structure in an optical image.
Implementation Method 2
The first pattern has a first transmittance to the light of the first wavelength. The second pattern has a second transmittance to the light of the first wavelength. The first transmittance is different from the second transmittance.
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate, a first conductive feature, a first light-emitting feature, a first pattern and a second pattern. The first light-emitting feature is disposed on the substrate. The first pattern is disposed on the first light-emitting feature. The second pattern is disposed on the first pattern. The first conductive feature is disposed on the substrate and at least laterally overlaps the first pattern. The first light-emitting feature is configured to emit a light of a first wavelength. The first pattern has a first transmittance to the light of the first wavelength. The second pattern has a second transmittance to the light of the first wavelength. The first transmittance is different from the second transmittance.