Direct, high throughput LIGA for commercial applications: a progress report

Abstract

Direct LIGA; LIGA without injection molding; has the potential to become a cost effective, high throughput form of LIGA. The process requires high energy photons; near 20,000 eV; which are best produced in facilities such as the X-ray ring at Brookhaven National Laboratory. The increased absorption lengths over lower energy photons eliminates the need for a membrane type X-ray mask. This in turn facilitates very large area X-ray masks fabricated from standard silicon wafers with 20 lm gold absorbers. The absorption length increase in PMMA to 2 cm is used to implement stacked PMMA exposures in which 1 mm thick PMMA layers are used to produce exposed PMMA sheets. These sheets are eventually solvent bonded to working substrates with plating bases.New high energy X-ray masks have been developed. Two exposure stations at Brookhaven are operational. The recently commissioned manufacturing exposure station which uses a 22 inch scanner which can expose four separate PMMA-mask combination is in the testing phase.

Numerical simulation and fabrication of microscale, multilevel, tapered mold inserts using UV-Lithographie, Galvanoformung, Abformung (LIGA) technology

“…The molding replication step of the three-step LIGA process of lithography, electrodeposition, and molding is the most important for low-cost HARMS production. Efforts of using LIGA or LIGA-like technologies for producing polymer-based, metal-based, and ceramic-based HARMS have been reported (Guckel et al 2000;Heckele and Schomburg 2004;Hupert and Witek 2003;Cao et al 2003Cao et al , 2004Cao and Meng 2004;Cao 2004;Dinakar 2003). X-ray lithography of PMMA produces high-quality plating molds, with attributes such as high aspect-ratios and vertical sidewalls.…”

“…X-ray lithography of PMMA produces high-quality plating molds, with attributes such as high aspect-ratios and vertical sidewalls. PMMA can also be easily removed after electrodeposition (Menz et al 1991;Mohr et al 1992;El-Kholi et al 1993;Kondo et al 1998;Ehrfeld and Schmidt 1998;Henry et al 1999;Guckel et al 2000;Singleton et al 2002;Schulz and Bade et al 2004;Heckele and Schomburg 2004). X-ray lithography of SU-8, a negative resist, has also been used in LIGA processing (Ryan 2002;Jian 2002;Turner and Desta et al 2003;Yang and Wang 2005) because of the much reduced exposure time.…”

“…In applications requiring metal-based or polymerbased microscale structures, the Lithographie, Galvanoformung, Abformung (LIGA) process is the preferred fabrication technology. The LIGA process, first developed using X-ray lithography of PMMA (Menz et al 1991;Mohr et al 1992;El-Kholi et al 1993;Kondo et al 1998;Ehrfeld and Schmidt 1998;Henry et al 1999;Guckel et al 2000;Singleton et al 2002;Schulz and Bade et al 2004;Heckele and Schomburg 2004), has been used to fabricate high-aspect-ratio microscale structures (HARMS) for applications in mechanical, electrical, chemical, and biomedical devices and systems (Menz et al 1991;Mohr et al 1992;El-Kholi et al 1993;Kondo et al 1998;Ehrfeld and Schmidt 1998;Henry et al 1999;Guckel et al 2000;Singleton et al 2002;Schulz and Bade et al 2004;Heckele and Schomburg 2004), including micro accelerator (Qu et al 1999), RF inductor (Sadler et al 2001), micro mixer/reactor (Yang et al 2004), polymerase chain reaction (PCR) system (Hupert and Witek 2003), and others. The molding replication step of the three-step LIGA process of lithography, electrodeposition, and molding is the most important for low-cost HARMS production.…”

Large batch dimensional metrology demonstrated in the example of a LIGA fabricated spring

“…The method of directly using the synchrotron mold for part production has generally been called "direct LIGA" [2]. LIGA is a German acronym for lithography, electroforming and molding.…”

UV-LIGA fabrication of microscale two-level mold inserts for MEMS applications

“…However, in applications that require metal/alloy or polymer microstructures, the LIGA (Lithographie, Galvanoformung, Abformung) process is the preferred fabrication technology. LIGA, first developed based on X-ray lithography of PMMA [1][2][3][4][5][6][7][8][9][10], has been used in fabrication of high-aspect-ratio microscale structures (HARMS) for a wide variety of applications in mechanical, electrical, chemical, biomedical devices and systems [1][2][3][4][5][6][7][8][9][10], examples include micro accelerator [11], RF inductor [12], micro mixer/reactor [13], polymerase chain reaction (PCR) system [14]. Conventional LIGA process includes three steps: lithography to produce plating patterns in resist, metal electrodeposition to make mold inserts, and compression molding with the insert to achieve low cost replications.…”