Optical Measurement for Die-Bonding Alignment With Dual Diffractive Marks
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Solution Overview
Problem
Existing optical measurement methods struggle to achieve precise die bonding alignment due to reduced bonding pad pitch and increased die size in advanced semiconductor systems, necessitating improved resolution and accuracy in aligning electronic devices on different substrates.
Innovation Solution
An optical measurement device incorporating a first align mark with a transmissive diffractive element and a second align mark with a reflective diffractive element, along with a beam splitter and focusing lens, to accurately measure alignment using nanostructures that maintain precision regardless of die size, enhanced by a polarization beam splitter for reduced light loss and improved sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical measurement methods are used, then the measurement process is simple, but measurement precision deteriorates due to reduced bonding pad pitch and increased die size
Solution Approach 1:
The measurement system is segmented into multiple functional components: a light source unit, a beam splitter, a first align mark with transmissive diffractive elements, a second align mark with reflective diffractive elements, a focusing lens, and an image sensor. Each component performs a specific function in the optical path to achieve precise alignment measurement through structured light interaction with the align marks.
Solution Approach 2:
The patent employs diffractive elements with specific structural parameters (period, depth, shape) that change the optical parameters of incident light. The transmissive and reflective diffractive elements modify light phase and direction based on their geometric parameters, enabling precise position detection despite variations in die size and bonding pad pitch.
2Reliability
If a single align mark is used, then the device structure is simple, but measurement reliability is insufficient for varying die sizes
Solution Approach 1:
The patent merges two distinct align mark structures into a single measurement system: a first align mark with transmissive diffractive elements and a second align mark with reflective diffractive elements. These marks work together to provide redundant and complementary measurement information, enhancing reliability across different die sizes and bonding configurations.
Solution Approach 2:
The dual align mark structure provides multi-functionality: the transmissive diffractive elements handle light transmission and diffraction for position encoding, while the reflective diffractive elements provide reflection-based position verification. This universal structure adapts to various die sizes and bonding pad pitches, ensuring reliable measurement across different semiconductor device configurations.
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 enables precise alignment measurement with minimal variation in precision across different die sizes, reducing alignment errors and enhancing the manufacturing process efficiency of electronic devices.
Implementation Method 1
a first align mark including at least one transmissive diffractive element
Implementation Method 2
a second align mark apart from the first align mark in a first direction and including at least one reflective diffractive element
Implementation Method 3
a second align mark apart from the first align mark in a first direction and including at least one reflective diffractive element
Implementation Method 4
a beam splitter configured to reflect incident light in a direction toward the first align mark and transmit light from the first align mark
Implementation Method 5
a focusing lens on a path of the light that passes through the beam splitter
Data Source
AI summary
An optical measurement device includes: a first align mark including at least one transmissive diffractive element; a second align mark apart from the first align mark in a first direction and including at least one reflective diffractive element; a beam splitter configured to reflect incident light in a direction toward the first align mark and transmit light from the first align mark; a focusing lens on a path of the light that passes through the beam splitter; and at least one image sensor configured to sense the light after the light passes through the focusing lens.