The major advantages of microtool fabrication using FIB include achieving more complex tool shape, better dimensional resolution, high repeatability, and online observation of the tool shaping process. FIB sputtering creates tool shapes that are beyond the capabilities of conventional techniques such as precise polishing and grinding. Moreover, a negligible mechanical force would affect the tool’s quality during the traditional tool fabrication methods.
The new method has a significant impact in many research areas, such as communications, healthcare, and electronics. However, some issues in microtool fabrication using FIB still need to be resolved as listed below.

Sharpness of the Tool

Current investigations reveal that the micro-cutting radius of as small as 15–20 nm is available on FIB-fabricated diamond tools, while 40 nm on hard alloy tool. However, a comprehensive study with the sharpness limits for diverse tool materials is needed to be investigated. Therefore, it appears to be more important to investigate the highest sharpness based on materials and fabrication methods.

Damage of FIB Sputtering on Tools and Its Alleviation Strategies

Ion beam inevitably brings damages to tools to be processed with nanometer-sized damage layer. Future work should concern on how to evaluate the FIB-induced damage and its mechanism and effectively alleviate it. 

Morphology Control in Fabrication and Efficiency

In the FIB milling process, ripples are apt to appear during the microtool surface fabrication, which would seriously influence the facial feature and degrade tool functionality. As a consequence, how to alleviate this effect and improve fabrication quality is valuable.
The FIB machining efficiency is generally lower than other micro-fabrication methods. Increasing the FIB efficiency is a key topic in future investigation. In order to improve it, the appropriate tool blank should be selected to reduce the removal of focused ion beam. The method of choosing the right assisted etching (e.g., the H2O) can effectively improve processing efficiency.

Future Development

One of the most important tendencies in manufacturing is miniaturization. Considering the increasing demand of MEMS, ultraprecise instruments, and so forth, smaller feature dimension and more complex shape would be critical issues in future manufacturing.
Tool with higher quality would certainly find wider market in practical use. To meet the requirements of use in complicated environment and obtain better fabrication results, properties of tool, including edge radius, form precision, effective longevity, and cost–performance, need to be advanced.