Pursuing denser data storage has driven researchers to refine the manufacturing process of 3D NAND flash memory, a type of digital memory that stacks data vertically to increase storage density. By investigating new approaches to making digital memory at the atomic scale, scientists have developed the ideal process for creating the narrow, deep holes required for this type of memory.
A recent study published in the Journal of Vacuum Science & Technology A revealed that plasma with hydrogen fluoride gas can etch these holes twice as fast as traditional methods, with etching rates increasing from 310 nanometers per minute to 640 nanometers per minute. This breakthrough in reactive ion etching has significant implications for the production of denser data storage devices, which will be crucial in meeting the growing demands of artificial intelligence and other data-intensive technologies.
By optimizing the recipe for creating these holes, researchers have laid the foundation for further innovation in semiconductor manufacturing, highlighting the importance of collaboration between industry, academia, and national laboratories in advancing our understanding of microelectronics.
Introduction to 3D NAND Flash Memory
The demand for denser data storage in electronic devices has led researchers to investigate new approaches to making digital memory at the atomic scale. One such effort focuses on developing the ideal manufacturing process for 3D NAND flash memory, which stacks data vertically to increase storage density. This type of nonvolatile data storage retains data even when the power is off and is commonly used in memory cards, computers, and other devices. The manufacturing process involves creating deep, narrow channels in semiconductor materials, which is a challenging task.
The use of plasma as a source of high-energy ions has been explored to create these small but deep circular holes needed for microelectronics. However, the process, known as reactive ion etching, isn’t fully understood and could be improved. Recent developments involve keeping the wafer at a low temperature, an approach called cryo etching. This emerging technique uses hydrogen fluoride gas to create the plasma, which has shown promising results in increasing the etching rate.
The Cryo Etching Process
Cryo etching is a process that uses low temperatures to create the deep, narrow channels in semiconductor materials. Traditionally, this process uses separate hydrogen and fluorine gases to make the holes. However, researchers have compared results from this traditional process to a more advanced cryo-etching process that uses hydrogen fluoride gas to create the plasma. The results show that the hydrogen fluoride plasma increases the etching rate compared to previous cryo-etch processes.
When silicon nitride and silicon oxide were tested separately, the etch rate increased for both materials using the hydrogen fluoride plasma instead of separate gases. The effect was more pronounced for silicon nitride than for silicon oxide. However, etching both materials simultaneously yielded the most significant increase, with the etching rate more than doubling from 310 nanometers per minute to 640 nanometers per minute.
Impact of Chemical Compounds on Etching Rate
The researchers also studied the impact of phosphorus trifluoride and ammonium fluorosilicate on the etching rate. Phosphorus trifluoride is an essential ingredient when etching silicon dioxide, and adding it quadrupled the etch rate for this material. However, it only marginally increased the silicon nitride etch rate. Ammonium fluorosilicate, which forms during the etching process, can slow down etching, but water can offset this effect by weakening the ammonium fluorosilicate bonds.
Conclusion
The development of 3D NAND flash memory relies on improving the manufacturing process, particularly in creating deep, narrow channels in semiconductor materials. Cryo etching with hydrogen fluoride plasma has shown promising results in increasing the etching rate and improving the quality of the etch. Further research is needed to fully understand the process and optimize its parameters. The collaboration between scientists from different fields and institutions is essential for advancing our understanding of semiconductor manufacturing processes and developing new technologies.
External Link: Click Here For More
