SOG Dispenser Nozzle Control for Uniform Wafer Coating
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Solution Overview
Problem
The uniformity of spin-on glass (SOG) deposition on semiconductor wafers is challenging due to the presence of particles and clumps in the SOG, leading to non-uniform coatings and potential defects in semiconductor devices.
Innovation Solution
A SOG dispensing system that includes a suck back valve and a sensor system to detect the presence of SOG outside the dispenser nozzle, allowing for the adjustment of the suck back valve to withdraw excess SOG and prevent unintentional dripping, thereby improving deposition uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid SOG is dispensed onto the semiconductor wafer, then the wafer surface is coated with SOG, but particles and clumps in the SOG cause non-uniform coating and defects
Solution Approach 1:
The system performs preliminary detection of SOG properties (viscosity, temperature, presence of particles/clumps) before dispensing onto the wafer. The suck back valve is adjusted in advance based on detected SOG characteristics to prevent excessive deposition and particle-related defects before they occur during the coating process.
Solution Approach 2:
The system continuously monitors SOG properties during dispensing and provides feedback to the suck back valve control mechanism. When particles, clumps, or abnormal viscosity/temperature are detected, the system automatically adjusts the suck back valve to withdraw excess SOG and maintain uniform coating quality, creating a closed-loop control system.
2Manufacturing precision
If the suck back valve is adjusted to withdraw excess SOG, then deposition uniformity is improved, but the system complexity increases
Solution Approach 1:
The system uses the SOG's own properties (viscosity, temperature, particle content) as the control signal for adjusting the suck back valve. The SOG essentially controls its own deposition process by providing feedback through its physical characteristics, eliminating the need for external complex control systems.
Solution Approach 2:
The system changes physical parameters of the SOG (temperature, viscosity) and uses these parameter changes as indicators for adjusting the suck back valve. By monitoring and responding to natural parameter variations in the SOG, the system achieves precise control without requiring complex additional instrumentation.
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 system effectively prevents excessive SOG deposition, reducing the presence of particles and clumps, which enhances the uniformity and quality of the SOG coating on semiconductor wafers, leading to improved semiconductor device performance.
Implementation Method 1
an emitter/detector pair 334, such as a laser/photodiode pair, to detect the position of the SOG 306
Implementation Method 2
the SB valve 322 has a switch valve 324 and an adjustment valve 326... adjusting, using a controller, a suck back (SB) valve to withdraw liquid SOG from the abnormal length
Data Source
AI summary
A method of manufacturing a semiconductor device includes detecting, using a sensor, liquid spin on glass (SOG) outside of a dispenser nozzle in an abnormal length relative to the dispenser nozzle. The method further includes adjusting, using a controller, a suck back (SB) valve to withdraw liquid SOG from the abnormal length. The method further includes comparing a sensed amount of liquid SOG deposited onto the semiconductor wafer from the dispenser nozzle with at least one set operating parameter. The method further includes pausing sensing of a duration of dispensing liquid SOG onto the semiconductor wafer based on the sensed amount of liquid SOG deposited being outside the at least one operating parameter.