Why a water fine filter can result in problems
Water that is used in microelectronics should contain no particles. Fine filters are widely used to improve wet etch equipment performance. The filter is expected to reduce the number of particles in the water.
The number of particles is defined by measuring the number of defects on a wafer.
Two experiments were conducted:
- A filter of 100 nm was instilled in the pure water system to reduce the number of particles and reduce the number of defects on the wafer. A positive result was received. The number of defects on the wafer reduces. The explanation of the improved performance is as follows: 100nm filter stops particles and improves the purity of the water.
- A filter of 10nm was installed in addition to a 100nm filter for the pure water system. It was expected that the water purity would be additionally improved and the number of defects on the wafer would be reduced. Nevertheless, the number of defects on the wafer increased. Replacement of the wafer of 10nm for the finer filter of 3 nm did not result in better performance.
The main question is - why do fine filters unexpectedly result in an increased number of defects?
What is the model of failure?
What is the solution?
Similar projects
Wet cleaning is widely used in microchip manufacturing. Single wafer equipment is working as follows. A wafer rotates, and chemistry is poured from a movable nozzle. Water rinsing is performed at the end of the process. Loading of a new batch of the chemistry resulted in excursion - a strongly increased amount of defects was observed on the wafer after the processing. The project is dedicated to the failure analysis and creation of innovative solutions.
This project applies Functional Modeling to analyze the single-wafer wet etch process in semiconductor manufacturing. The model shows that wet etch defects are not caused only by chemistry, but also by interactions between the wafer, liquid flow, air, rotation, rinsing, drying, drain, and chamber environment. Key challenges include incomplete wetting, trapped air or bubbles, residue and particle redeposition, evaporation-driven watermarks, and contamination during rinse or drying. The project identifies improvement directions such as better wafer pre-wetting, controlled airflow, reduced evaporation, optimized rinse and drying conditions, and alternative chamber concepts such as face-down processing in a shallow liquid bath.
Flash heating of a wafer is widely used in microchip manufacturing. The purpose of the process is to prevent the diffusion of ions and atoms. During the flash process, a wafer breakage occurs. The project's purpose is to learn and understand the mechanism of the wafer breakage and propose the solutions to prevent the wafer breakage