LIGA technology

Silicon-type mixers using the separation-reunification principle have been reported by PNNL [8], Danfoss [9] and DMST [27]. Polymeric analogues made by LIGA technology have been reported by IMM [25] (see Fig. 5). 

Optical devices are preferentially integrated in optoelectronic circuits. State-of-the-art microfabrications, such as with LIGA technology, miniaturised laser diodes, etc., make sophisticated, small and rigid optical sensors and actuators possible. 

Figure 1. Schematic process steps of the LIGA technology. Reprinted from Ref. 1, Copyright (1996) with permission from Taylor Francis Books (UR).

Malek CK, Salle V (2004) Applications of LIGA technology to precision manufacturing of high-aspect-ratio micro-components and -systems a review. Microelectronics J 35 131-143... 

Figure 1.7 Micro-gear system produced from a nickel iron alloy by means of LIGA technology [Source Micromotion, IMM) [108]. Reproduced by kind permission from the publisher.

The original motivation to develop the LIGA technology was to make micronozzles for the refinement of uranium isotopes [1]. These micronozzles have minimum feature of... 

The basic elements of X-ray-based LIGA technology consist of X-ray source, LIGA mask, and thick resist process [2]. 

Although LIGA technology is able to make microstmctures with very high aspect ratio and very vertical sidewalls, there are some factors which have limited further improvements in pattern accuracy, minimum feature size, and sidewall verticality in LIGA. These factors include X-ray diffiraction and photoelectron scattering, penumbra effect, non-vertical sidewall in absorber patterns, mask distortion, and secondary electrons induced by X-ray in substrate material [6]. 

The original motivation to develop the LIGA technology was to make micronozzles for the refinement of uranium isotopes [ 1 ]. These micronozzles have minimum feature of micrometers, but the overall sfructure is of millimetres. Fig. 2a is one of such micronozzles in PMMA resist. Fig. 2b is the electroplated nickel sfructure from the resist mould and Fig. 2c is the plastic replication of the micronozzle. 

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