In-Situ Variable-Temperature Bow Metrology for Wafer Stability
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Solution Overview
Problem
Wafers become non-planar (bowing) after processing, leading to instability and potential breakage during elevated temperature processing steps, with existing measurement methods failing to provide accurate stress insights at these temperatures.
Innovation Solution
A measurement device with a measurement vessel, pins, and a heater that allows in-situ measurement of wafer bow at elevated temperatures, using thermal conduction and convection to control temperature within the vessel, combined with bow measurement devices for precise z-direction height deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used at room temperature, then measurement simplicity is maintained, but measurement precision at processing temperatures is insufficient
Solution Approach 1:
The patent combines the heating function and measurement function into a single integrated measurement vessel. The heater elements are positioned within the same chamber where the bow measurement device operates, allowing temperature control and measurement to occur simultaneously in the same environment, thereby achieving elevated temperature measurement capability without requiring separate complex systems.
Solution Approach 2:
The measurement vessel acts as an intermediary chamber that mediates between the heater and the bow measurement device. It provides a controlled thermal environment that allows the bow measurement device to accurately measure wafer bow at elevated temperatures by isolating the measurement process from ambient temperature fluctuations while maintaining thermal stability.
2Reliability
If wafers are processed at elevated temperatures without stability assessment, then processing efficiency is maintained, but wafer breakage risk increases
Solution Approach 1:
The system performs preliminary bow measurements at elevated temperatures before the actual processing steps. By assessing wafer stability in advance at the same temperature conditions where processing will occur, the system identifies potentially unstable wafers that could break during processing, allowing them to be removed or reprocessed before they cause production delays or damage to expensive equipment.
Solution Approach 2:
The measurement system provides real-time feedback on wafer bow and stability at elevated temperatures. This feedback loop allows operators to monitor wafer condition during temperature cycling and make informed decisions about whether to proceed with processing, adjust processing parameters, or remove problematic wafers, thereby preventing breakage while maintaining efficient throughput.
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 predictive assessment of wafer stability at elevated temperatures, preventing breakage and optimizing processing by identifying 'good' or 'bad' wafers, thus reducing downtime and resource waste.
Implementation Method 1
using thermal conduction and convection to control temperature within the vessel
Implementation Method 2
using thermal conduction and convection to control temperature within the vessel
Implementation Method 3
The heater can be configured to send electrical charges through the pins to the wafer to heat up the wafer to the first temperature
Data Source
AI summary
Aspects of the present disclosure provide a measurement device. For example, the measurement device can include a measurement vessel providing an enclosed space for a wafer to be placed therein, and a plurality of pins provided in the measurement vessel for the wafer to rest thereon. The pins can be configured to be raised to a first position and lowered to a second position. The measurement device can also include a heater configured to control the enclosed space to reach a first temperature elevated from a second temperature, and a bow measurement device configured to measure the wafer to identify a bow of the wafer when the wafer rests on the pins and the pins are raised to the first position.