Load Port Weighing Control for Balanced Wafer Spin Drying
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Solution Overview
Problem
In integrated circuit manufacturing, existing methods for rotational balancing in spin dryers fail to accurately account for weight differences between lots of wafers, leading to potential unbalanced rotation, equipment damage, and process stoppages when wafers of different weights are spun together.
Innovation Solution
A system that uses sensors to detect weight differences between lots of wafers and converts this information into a number of wafers with a predetermined weight, enabling a controller to adjust counterweights for precise rotational balancing during spinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafers of different weights are spun together in a spin dryer, then productivity is improved by processing multiple lots simultaneously, but rotational balancing deteriorates leading to equipment damage and process stoppages
Solution Approach 1:
The system performs preliminary weighing of wafers in each lot using sensors before spinning. The controller receives weight information and calculates the number of wafers in each lot, then uses this information in advance to adjust counterweights and balance the rotation before the actual spinning process begins
Solution Approach 2:
The system uses sensors to detect the actual weight of wafers in each lot, feeds this weight information back to the controller, which then adjusts the counterweights based on the detected weight differences to achieve rotational balancing
2Device complexity
If weight differences between wafer lots are not accurately detected, then device complexity is reduced by omitting weighing mechanisms, but manufacturing precision deteriorates due to inaccurate weight distribution information
Solution Approach 1:
The system replaces complex mechanical weighing mechanisms with sensors that electronically detect wafer weight. The sensors generate weight signals that are processed by a controller to determine the number of wafers, eliminating the need for mechanical balances while achieving precise weight measurement
Solution Approach 2:
The system uses the existing spin dryer structure and integrates sensors within it, allowing the spin dryer to perform both its primary drying function and wafer weighing function without requiring separate dedicated weighing equipment
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
Ensures rotational balancing across varying wafer weights, reduces equipment wear, minimizes alarms and downtime, and enhances tool availability by accurately reflecting weight distribution within the spin dryer.
Implementation Method 1
at least one sensor configured to generate a first weight signal corresponding to a first weight of a first lot of wafers and a second weight signal corresponding to a second weight of a second lot of wafers
Implementation Method 2
rotated by the spin dryer at high speed to remove the liquid remaining on the cleaned wafers by centrifugal force
Data Source
AI summary
A system includes at least one sensor and at least one controller. The at least one sensor is configured to generate a first weight signal corresponding to a first weight of a first lot of substrates, and a second weight signal corresponding to a second weight of a second lot of substrates. The at least one controller is coupled to the at least one sensor to receive the first weight signal and the second weight signal. The at least one controller is configured to convert a weight difference between the first weight and the second weight into a number of substrates each having a predetermined weight. The at least one controller is further configured to, based on the converted number of substrates, control a processing apparatus to rotate the first lot of substrates and the second lot of substrates simultaneously.