Application of focused ion beam milling in the metrology of 3D NAND and other advanced memory devices.
As 3D NAND layer counts increase, the ability to see through the stack becomes critical to driving process improvements, yield loss reductions and faster time-to-ramp. Where conventional metrology does not provide full-depth access to CD measurements, focused ion beam (FIB) metrology provides the ability to slice through the structure from top to bottom to expose structural defects and features for analysis.
Metrology, the process of measuring these critical dimensions (CD), stands out as one of the main technological challenges. It is difficult to measure CDs of HAR structures in 3D NAND, as the structure of the memory layers does not allow conventional metrology equipment to access these features throughout their depth, especially in the middle regions and the bottom of the stacks. Legacy metrology tools have limitations, leaving manufacturers without a method to accurately measure HAR structures quickly. Ultimately, this adds up to more cost, process complexity, and delays in bringing the next technology to market.
This important white paper discusses new techniques to view and measure high aspect ratio devices more precisely.
Download the whitepaper to learn about:
- 3D NAND metrology challenges
- Diagonal milling and layer-by-layer deposition to expose and measure CDs
- How in-line metrology can reduce time to data and development costs