Semiconductor Pattern Displacement Measurement Using Zero-Order Diffraction
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Solution Overview
Problem
Existing methods for measuring positional displacement of patterns in semiconductor devices with three-dimensional structures are inaccurate due to the difficulty in forming alignment marks in the same region as the circuit and device patterns, leading to incorrect displacement calculations.
Innovation Solution
A measurement apparatus and method that measures relative positional displacement of partial patterns using a combination of two-dimensional intensity distributions from zero-order diffraction light, synthesized to calculate accurate displacement amounts through a calculation device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alignment marks are formed in the same region as circuit and device patterns, then measurement accuracy of positional displacement is improved, but manufacturing complexity increases
Solution Approach 1:
The invention merges the alignment mark formation process with the existing circuit and device pattern formation processes. By using the same lithography and etching steps to create both functional patterns and alignment marks simultaneously, the patent eliminates the need for separate alignment mark formation steps, thereby improving measurement accuracy without adding manufacturing complexity
Solution Approach 2:
The alignment marks are designed to serve multiple functions: they act as both alignment references for subsequent lithography steps and as measurement targets for positional displacement detection. This multi-functionality allows the same structural features to provide both manufacturing guidance and quality control data
2Ease of manufacture
If conventional alignment mark methods are used in three-dimensional semiconductor structures, then manufacturing process is simple, but measurement accuracy of pattern positional displacement deteriorates
Solution Approach 1:
The invention transitions from conventional two-dimensional alignment mark patterns to three-dimensional patterns that include vertical structures such as fins, trenches, and stacked features. These 3D patterns are formed using the same manufacturing processes as the device structures, maintaining ease of manufacture while providing multiple measurement points and improved accuracy for detecting positional displacements in three-dimensional semiconductor devices
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 measurement of pattern displacements in complex semiconductor structures, improving overlay accuracy and ensuring normal operation of semiconductor devices by adjusting pattern positions.
Implementation Method 1
measuring a plurality of two-dimensional intensity distributions having a first two-dimensional intensity distribution and a second two-dimensional intensity distribution, the first two-dimensional intensity distribution being formed by applying a first illumination light having a first illumination shape to a region on which the complex pattern is measured and detecting only zero order diffraction light from the region via a first filter
Data Source
AI summary
A measurement apparatus which measures a relative positional displacement amount of a partial pattern to another pattern in a complex pattern on a surface of an object, includes: a measurement part to measure two-dimensional intensity distributions having a first and a second two-dimensional intensity distribution, the first distribution being formed by applying first light having a first shape to a region on which the complex pattern is measured and detecting only zero order diffraction light from the region via a first filter, and the second distribution being formed by applying second light having a second shape to the region and detecting only zero order diffraction light from the region via a second filter; a storage part to store measurement data indicating the distributions; and a calculation part to form a synthesized intensity distribution obtained by the two-dimensional intensity distributions to calculate a positional displacement amount of the partial pattern.