Wafer cleaning issues at the wet process
Current situation
Defects were found on the surface of the wafer after washing with the chemistry and rinsing with water.
Disadvantages
- The wafer contaminated with defects cannot be sold to the customer. The defective wafers will be scrapped.
- The process strongly depends on chemicals. Small change, even within spec limits, causes contamination of the wafers and a drop in the yield.
- The process and products are at high risk of failure due to even insignificant changes.
Problem statement
Defects remain on the wafer surface after the wet cleaning process step.
Success criteria
Stable yield after using the chemistry from different vendors with no cost increase.
Similar projects
The project was dedicated to production yield improvement in microchip manufacturing. The bumps are created on the top of a wafer and used for the final test of all dies. Only good dies are taken for the packaging. All dies that fail the test will be scrapped. The process yield depends on the amount of "good" and "bad" dies. It was revealed that in some cases, the time between the end of the process and the final test impacts the yield. The longer the dwelling, the more dies fail the final test. If the dwelling exceeds hundreds of hours, the amount of failed dies becomes dramatically high, which results in the scrapping of the whole wafer. The problem was analyzed and solved.
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
The process is related to microelectronics - microchip manufacturing. The purpose of the process is to create a SiO2 layer on the surface of a Si wafer. Equipment: Vertical furnace to heat the wafers in the Q2 atmosphere and perform oxidation on the wafer surface. Process: The oxidation occurs on the front side and on the back side of the wafer Requirements: Create a SiO2 thin layer with a certain thickness and low sigma - low standard deviation of the thickness between the wafers and within the wafer Failure: Wafers from the lower zone have higher thickness and significantly higher within wafer sigma (standard deviation of the thickness within the wafer)