Glass micromachining is currently becoming essential for the fabrication of micro-devices, including micro- optical-electro-mechanical-systems (MOEMS), miniaturized total analysis systems (μTAS) and microfluidic devices for biosensing. Moreover, glass is radio frequency (RF) transparent, making it an excellent material for sensor and energy transmission devices. Advancements are constantly being made in this field, yet machining smooth through-glass vias (TGVs) with high aspect ratio remains challenging due to poor glass machinability. As TGVs are required for several micro-devices, intensive research is being carried out on numerous glass micromachining technologies. This paper reviews established and emerging technologies for glass micro-hole drilling, describing their principles of operation and characteristics, and their advantages and disadvantages. These technologies are sorted into four machining categories: mechanical, thermal, chemical, and hybrid machining (which combines several machining methods). Achieved features by these methods are summarized in a table and presented in two graphs. We believe that this paper will be a valuable resource for researchers working in the field of glass micromachining as it provides a comprehensive review of the different glass micromachining technologies. It will be a useful guide for advancing these techniques and establishing new hybrid ones, especially since this is the first broad review in this field.

Additive manufacturing (AM) is gaining more attention due to its capability to produce customized and complex geometries. However, one significant drawback of AM is the rough surface finish of the as‐built parts, necessitating post‐processing for achieving the desired surface quality that meets application requirements. Post‐processing of complex geometries, such as parts with internal holes, lattice structures, and free‐form surfaces, poses unique challenges compared to other components. This review classifies various post‐processing methods employed for complex AM parts, presenting the experimental conditions for each treatment alongside the resulting improvement in surface roughness as a success criterion. The post‐processing methods are categorized into four groups: electrochemical polishing (ECP), chemical polishing (CP), mechanical polishing, and hybrid methods. Notably, mechanical methods exhibit the highest roughness improvement at 69.9%, followed by ECP (59.9%), hybrid methods (47.4%), and CP (49.5%). Nevertheless, mechanical post‐processing techniques are less frequently utilized for lattice parts, making chemical or electrochemical methods more promising alternatives. In summary, all four categories of post‐processing methods can improve the internal surfaces quality of AM holes. While mechanical methods offer the most substantial roughness improvement overall, chemical and electrochemical methods show particular potential for addressing the challenges associated with complex geometries.