Wafer Capacitance Sensing for Thickness and Bonding Void Inspection
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Solution Overview
Problem
Current methods for measuring wafer thickness and inspecting bonding voids in semiconductor fabrication are time-consuming and prone to damage, with limited spatial resolution and the need for dedicated measurement environments, which hinders accurate characterization and increases manufacturing delays.
Innovation Solution
Incorporating dielectric structures on the target semiconductor wafer before bonding, which are filled with dielectric material and used to measure capacitance changes when exposed during thinning, allowing for in-situ detection of bonding voids and accurate thickness measurement using a conductive bond chuck and probe pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical methods are used to detect bonding voids and measure wafer thickness, then measurement can be performed, but the process is time-consuming and requires separate dedicated measurement environments
Solution Approach 1:
The patent combines the wafer bonding process with thickness measurement and void detection into a single integrated process. The conductive bond chuck serves dual purposes: bonding the wafer to the carrier substrate and simultaneously measuring wafer thickness through capacitance sensing, eliminating the need for separate measurement environments and reducing measurement time.
Solution Approach 2:
The conductive bond chuck is designed with multi-functionality, serving as both a bonding tool and a measurement device. It can detect bonding voids, measure wafer thickness, and monitor the bonding process simultaneously, replacing multiple dedicated measurement instruments and reducing overall process time.
2Reliability
If conventional optical methods are used for bonding void inspection, then void detection can be achieved, but spatial resolution is limited
Solution Approach 1:
The patent replaces optical detection methods with an electrical field-based capacitance sensing system. The conductive bond chuck creates an electrical field that interacts with the wafer and carrier substrate, allowing detection of bonding voids through capacitance changes. This electrical field method provides superior spatial resolution compared to optical methods.
3Length of moving object
If wafer thinning is performed to reduce thickness to 10 μm or less, then device size is reduced and performance improved, but the risk of damage to circuit components increases
Solution Approach 1:
The patent implements real-time feedback control during the wafer thinning process. The conductive bond chuck continuously measures wafer thickness through capacitance sensing, and the thinning process is dynamically adjusted based on this feedback. This ensures the wafer is thinned to the target thickness of 10 μm or less without over-thinning that would damage circuit components.
Solution Approach 2:
The patent performs preliminary bonding of the wafer to the carrier substrate before thinning. This preliminary action provides mechanical support and protection to the wafer during the subsequent thinning process, reducing the risk of damage to circuit components while enabling aggressive thinning to ultra-thin dimensions.
4Strength
If wafer bonding is performed to enhance structural integrity for thinning, then mechanical stability is improved, but the complexity of the bonding process increases
Solution Approach 1:
The patent merges the bonding process with thickness measurement and void detection into a single integrated operation. The conductive bond chuck performs bonding while simultaneously measuring wafer thickness and detecting voids, reducing overall process complexity despite the enhanced bonding requirements for structural integrity.
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
This method enables quick and accurate measurement of wafer thickness and detection of bonding voids without the need for separate measurement environments, improving manufacturing efficiency and reducing the risk of damage to semiconductor components.
Implementation Method 1
measure capacitances across the bonded structure to determine a remaining thickness of the target semiconductor wafer
Data Source
AI summary
Methods, apparatuses, and systems related to a semiconductor apparatus having one or more dielectric structures used to detect bonding voids during manufacturing. In some embodiments, a semiconductor wafer includes the dielectric structures. After the wafer is bonded to another structure, capacitances may be measured across the dielectric structures and the other wafer. The measured capacitance can be used to detect or characterize any bonding voids that may have been introduced during the wafer bonding process.