Integrated Alignment and Overlay Marks for Semiconductor Dicing
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Solution Overview
Problem
In semiconductor device manufacturing, reducing the area of dicing lines to increase memory cell region area is challenging due to the presence of various marks used for alignment and overlay measurements, which are typically arranged on these lines.
Innovation Solution
A position measuring method and apparatus that utilize first and second marks with specific segment arrangements, where the first marks are irradiated with light of wavelength λ1 for alignment measurement and the second marks with light of wavelength λ2 for overlay measurement, allowing the same marks to perform both functions with high accuracy and reducing the number of marks needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If various types of marks are arranged on dicing lines for alignment and overlay measurements, then measurement accuracy is ensured, but the area of dicing lines increases
Solution Approach 1:
The patent combines alignment mark and overlay mark functions into a single integrated mark structure. The mark includes a first mark portion for alignment measurement and a second mark portion for overlay measurement, allowing both measurement types to be performed using one mark rather than separate marks, thereby reducing the total area required on dicing lines
Solution Approach 2:
The integrated mark structure serves multiple functions: it acts as both an alignment mark for positioning the mask in the light exposure apparatus and an overlay mark for determining overlay deviation between stacked layers. This multi-functionality eliminates the need for separate dedicated alignment and overlay marks, reducing the area occupied by marks on dicing lines
2Quantity of substance
If the area of memory cell region is increased to enhance storage capacity, then storage capacity improves, but the area available for mark arrangement decreases
Solution Approach 1:
By merging alignment and overlay mark functions into a single integrated mark, the total area required for mark arrangement is reduced. This freed-up space can then be reallocated to expand the memory cell region, thereby increasing storage capacity without compromising measurement functionality
Solution Approach 2:
The invention extracts and eliminates redundant mark structures by using a single integrated mark instead of multiple separate marks. This removal of unnecessary mark area allows for expansion of the memory cell region while maintaining all required measurement capabilities
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 accurate alignment and overlay measurements while minimizing the area required for mark arrangement, thereby increasing the memory cell region area and enhancing storage capacity.
Implementation Method 1
alignment measurement in a light exposure process is executed by irradiating a first mark with light having a wavelength of λ1
Implementation Method 2
overlay measurement is executed by irradiating the first mark and a second mark with light having a wavelength of λ2 shorter than the wavelength of λ1
Data Source
AI summary
According to one embodiment, in a position measuring method, alignment measurement in a light exposure process is executed by irradiating a first mark with light having a wavelength of λ1, with respect to a processing object that includes a first layer and a second layer stacked above a substrate and a resist applied on the second layer. The first mark is provided in the first layer and includes a plurality of segments arranged at a pitch smaller than a resolution limit given by light having the wavelength of λ1. Then, overlay measurement is executed by irradiating the first mark and a second mark with light having a wavelength of λ2 shorter than the wavelength of λ1. The second mark has been formed by performing a light exposure and development process to the resist, and includes a plurality of segments arranged at the pitch.