Weighing Support Resistance Path for Electrostatic Discharge Control
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Solution Overview
Problem
Electrostatic forces between charged semiconductor wafers and weighing device components cause measurement errors and potential damage to sensitive electronic components due to uncontrolled discharge spikes.
Innovation Solution
A support for weighing devices with a predetermined electrical resistance between 100 kΩ and 10 MΩ, allowing controlled discharge of electric charge through a conductive path to prevent measurement errors and component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all components of the weighing pan are made from conductive materials to allow charge discharge, then electrostatic forces causing measurement errors are reduced, but discharge spikes may damage sensitive electronic components in the load cell
Solution Approach 1:
A discharge control circuit is introduced as an intermediary between the conductive weighing pan and the load cell. This circuit mediates the discharge process by controlling the rate and path of charge flow, preventing direct high-voltage spikes from reaching the load cell while still allowing electrostatic discharge to occur. The circuit acts as a buffer that protects sensitive components while maintaining the beneficial discharge function.
Solution Approach 2:
The electrical parameters of the discharge path are modified by introducing resistance and capacitance elements in the discharge control circuit. By changing the time constant (RC product) and limiting current, the discharge profile is transformed from a dangerous high-voltage spike into a controlled, gradual discharge that protects the load cell. The circuit parameters are specifically chosen to allow complete discharge while limiting peak current to safe levels.
2Measurement precision
If a large electrostatic charge is present on the wafer, then complete discharge is needed for accurate measurement, but the discharge spike may affect and damage sensitive electronic components in the load cell
Solution Approach 1:
The discharge control circuit is pre-configured with protective elements (resistors, capacitors, diodes) that cushion the impact of large discharge spikes before they can reach the load cell. This prior cushioning ensures that even when large charges are present on wafers, the discharge process is safely managed without threatening component reliability.
Solution Approach 2:
The discharge control circuit incorporates feedback mechanisms that monitor the discharge process and adjust the discharge rate accordingly. When large charges are detected, the circuit automatically adjusts its parameters to ensure complete discharge while maintaining protection levels. This feedback control ensures both measurement precision and component reliability are maintained under varying charge conditions.
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 ensures consistent and accurate weight measurements by controlling discharge spikes, reducing residual charge, and protecting sensitive components from damage.
Implementation Method 1
the support part and the mounting part are electrically connected by a component having an electrical resistance greater than or equal to 100 kΩ and less than or equal to 10 MΩ
Implementation Method 2
any electric charges on the wafer can freely discharge through the weighing pan to the load cell when the wafer is on the weighing pan
Data Source
AI summary
A support for a weighing device, the support comprising: a support part for supporting an object during a weight measurement; and a mounting part for mounting the support on a weighing device; wherein the support part and the mounting part are electrically connected by a component having an electrical resistance greater than or equal to 100 kΩ and less than or equal to 10 MΩ.