E-Beam Inspection Tool Thermal Equilibrium Control
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Solution Overview
Problem
Current electron beam inspection tools face significant downtime due to the lengthy process of reaching thermal equilibrium, which is necessary for reliable inspections, as the object table and substrate must reach a stable temperature, often taking several hours, affecting device yield and performance.
Innovation Solution
Incorporating a heating device within the positioning device of the electron beam inspection tool to generate a controlled heat load that exceeds the nominal heat loads, allowing the object table to reach thermal equilibrium faster, typically within 10 to 15 minutes, by using electric or inductive heating devices and a heat load controller to manage the temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the object table and substrate are allowed to reach thermal equilibrium naturally without additional heating, then the thermal stability is maintained, but the time required to reach operational thermal equilibrium becomes excessively long (several hours)
Solution Approach 1:
The heating device is activated before the inspection process to pre-heat the object table and substrate, allowing them to reach thermal equilibrium faster. This preliminary heating action eliminates the long waiting period that would otherwise be required for natural thermal stabilization.
Solution Approach 2:
The system actively controls the temperature parameter of the object table using a heating device, transitioning from passive natural cooling to active thermal management. This allows the system to reach and maintain the desired thermal equilibrium state much more quickly.
2Loss of time
If the heating device generates excessive heat load, then the thermal equilibrium is reached faster, but the temperature stability and inspection accuracy may be compromised
Solution Approach 1:
The heat load controller continuously monitors the temperature of the object table and substrate, and adjusts the heating power accordingly. This feedback control ensures that the heating process reaches thermal equilibrium quickly while preventing overheating that would compromise inspection accuracy.
Solution Approach 2:
The heating system operates dynamically, adjusting its power output based on the current thermal state of the object table. The system applies higher power initially to reach equilibrium faster, then reduces power to maintain stable temperature, optimizing both speed and precision.
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 solution significantly reduces the time to reach thermal equilibrium, minimizing downtime and ensuring accurate inspections by maintaining the object table at a stable temperature, thus improving tool availability and inspection quality.
Implementation Method 1
by using electric or inductive heating devices
Implementation Method 2
by using electric or inductive heating devices
Implementation Method 3
the vacuum chamber comprises an electromagnetic shield and wherein the electromagnetic shield comprises an absorptive coating
Data Source
AI summary
An e-beam inspection tool is disclosed, the tool comprising, an electron optics system configured to generate an electron beam, an object table configured to hold a specimen, a positioning device configured to position the object table, the positioning device comprising an actuator, wherein the positioning device further comprises a heating device configured to generate a heat load and a heat load controller to control the generated heat load at least partly based on an actuator heat load generated in the actuator.