Parallelism Measurement Optical System Module
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Solution Overview
Problem
Conventional technologies for measuring parallelism between a die and a wafer are influenced by the tilt of the measurement apparatus, resulting in errors and low measurement sensitivity, particularly due to space constraints in optic configurations.
Innovation Solution
A parallelism measurement optical system module that includes a polarization beam splitter, mirrors, and quarter wave plates to separate and manipulate reference and measurement light, enabling accurate determination of parallelism between specimens with improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional parallelism measurement apparatus is used, then measurement can be performed, but measurement sensitivity is low and errors occur due to apparatus tilt
Solution Approach 1:
A polarization beam splitter is introduced as an intermediary component to separate incident light into reference light and measurement light. This mediator enables independent optical paths that eliminate the influence of apparatus tilt on measurement accuracy, thereby improving both measurement sensitivity and reliability simultaneously
Solution Approach 2:
The system changes the polarization state of light using quarter wave plates to manipulate the optical paths of reference and measurement light differently. By changing polarization parameters, the system can distinguish between apparatus tilt and actual specimen parallelism, resolving the measurement accuracy issue
2Volume of moving object
If optic configuration space is limited, then device size is reduced, but sufficient optical path configuration becomes difficult
Solution Approach 1:
The patent utilizes the polarization dimension of light to create separate optical paths for reference and measurement light. By exploiting this additional dimension rather than requiring separate physical spaces, the system achieves complex optical functionality within a compact volume, resolving the contradiction between size and configuration capability
3Measurement precision
If measurement sensitivity is improved, then alignment precision is enhanced, but system complexity increases
Solution Approach 1:
The optical system is segmented into distinct functional components: a polarization beam splitter that divides light into reference and measurement paths, quarter wave plates that manipulate polarization states, and a mirror that redirects light. This segmentation allows each component to perform a specific function efficiently, achieving high measurement sensitivity while keeping the overall system manageable through modular design
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 solution enhances measurement sensitivity by about two times compared to prior art, allowing for precise alignment of dies and wafers, which is critical for hybrid bonding in semiconductor processes.
Implementation Method 1
a polarization beam splitter configured to separate incident light into reference light and measurement light
Implementation Method 2
the first quarter wave plate is arranged to change a polarization state of the measurement light reflected from the polarization beam splitter toward the first specimen, the first quarter wave plate being further arranged to change a polarization state of the measurement light reflected from the first specimen
Implementation Method 3
a mirror positioned on a first surface of the polarization beam splitter and configured to reflect the reference light that has passed through the polarization beam splitter back to the polarization beam splitter
Implementation Method 4
wherein the measurement light reflected twice each from the first specimen and the second specimen passing through the first quarter wave plate and the second quarter wave plate is emitted with parallelism information of the first specimen and the second specimen
Data Source
AI summary
A parallelism measurement optical system module includes a polarization beam splitter, a mirror positioned on a first surface of the polarization beam splitter, a first quarter wave plate positioned on a second surface of the polarization beam splitter that is perpendicular to the first surface, and a second quarter wave plate positioned on a third surface of the polarization beam splitter that is perpendicular to the first surface and parallel to the second surface.