Testing Wafer Heater Pattern for Vacuum Thermal Stress
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Solution Overview
Problem
Current wafer inspection devices face challenges in applying consistent thermal stress, especially in vacuum attraction states, due to heat escape when inspecting semiconductor devices under varying temperature conditions, which affects the performance evaluation of chillers.
Innovation Solution
A testing wafer with a heater pattern and temperature sensors, designed to simulate heat generation and maintain temperature uniformity, allowing thermal stress application in a vacuum attraction state by controlling heat distribution and measuring temperatures for precise temperature management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal stress is applied during wafer inspection in vacuum attraction state, then the inspection accuracy is improved, but heat escape occurs causing temperature uniformity to deteriorate
Solution Approach 1:
The wafer is divided into multiple temperature control zones with independent heating and cooling elements. Each zone can be controlled separately to maintain temperature uniformity across the entire wafer surface even during thermal stress application in vacuum conditions.
Solution Approach 2:
Multiple temperature sensors are distributed across the wafer surface to provide real-time temperature feedback. The control system uses this feedback to dynamically adjust heating and cooling power, maintaining temperature uniformity during thermal stress application for improved inspection accuracy.
2Reliability
If heater pattern is used to simulate heat generation, then thermal stress application is improved, but device complexity increases
Solution Approach 1:
The heater pattern uses variable resistance elements with different power consumption levels to simulate different heat generation scenarios. By changing electrical parameters (voltage, current, resistance) rather than physical structure, thermal stress application is improved without significantly increasing device complexity.
Solution Approach 2:
The heater pattern serves multiple functions: it generates thermal stress for inspection, acts as a temperature reference, and can be controlled to simulate different operating conditions. This multi-functionality improves thermal stress application reliability without proportionally increasing device complexity.
3Measurement precision
If multiple temperature sensors are installed to measure temperatures, then temperature measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple temperature sensors are arranged in a standardized pattern that can be replicated across different wafers. This copying approach improves temperature measurement precision through multiple data points while reducing manufacturing complexity by using repeatable sensor placement and identical sensor types.
Solution Approach 2:
Identical temperature sensor types are used throughout the wafer surface, ensuring homogeneous measurement characteristics. This standardization improves measurement precision through consistency while simplifying manufacturing by eliminating the need to handle different sensor types.
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 accurate thermal stress application in vacuum attraction states, enhancing the evaluation of chiller performance and improving inspection efficiency by maintaining consistent temperature conditions.
Implementation Method 1
a heater pattern configured to heat the testing wafer
Implementation Method 2
a plurality of temperature sensors configured to respectively measure temperatures of multiple locations on the testing wafer
Implementation Method 3
a testing wafer to which thermal stress can be applied in a vacuum attraction state
Data Source
AI summary
There is provided a testing wafer that simulates heat generation of an inspection target substrate. The testing wafer includes a heater pattern, a plurality of temperature sensors, and first and second electrode pads. The heater pattern is configured to heat the testing wafer having the same shape as a shape of the inspection target substrate. The temperature sensors are configured to respectively measure temperatures of multiple locations on the testing wafer. The first electrode pads are connected to the heater pattern and the second electrode pads are connected to the temperature sensors. The first and second electrode pads are installed to be in contact with probes of a probe card.