Manufacturing of the ISO 25178-70 material measures with direct laser writing: a feasibility study

Abstract

The standard ISO 25178-70 defines material measures for the calibration of 2D-and 3D-topography measurement devices. Some of the suggested material measures are established within the industrial application for a long time while others have not yet been extensively researched regarding their practical abilities. This paper describes a holistic and systematic investigation of the ISO 25178-70 material measures. The manufacturing of the suggested geometries is executed with twophoton laser lithography, alias direct laser writing (DLW). Since this manufacturing process is not yet frequently used in a material measures context, it is examined regarding its suitability for the fabrication of the ISO 25178-70 material measures. With DLW, it is possible to manufacture multiple material measures on one sample in order to enable a comprehensive calibration of optical topography measurement devices. The manufactured ISO 25178-70 geometries are examined using different 3D-topography measuring devices. In doing so, their abilities regarding the calibration of the devices can be evaluated and the practical feasibility of their industrial application is assessed. For the review of this practical usefulness, varying calibration and evaluation strategies are taken into account.

Comparison of material measures for areal surface topography measuring instrument calibration

“…Depending on the geometry and size of the structures to be manufactured, a wide range of different manufacturing principles has been utilized for their production. An overview on previous studies on the manufacturing of material measures has already been presented by some of the authors [12,22,23]. The methods range from ultraprecision cutting processes, such as micro-milling [24][25][26][27] to classical processes from microtechnology, such as focused ion beam [28] or lithographic methods [29].…”

Compatibility analysis of profile and areal material measures

“…All material measures were manufactured by additive manufacturing, namely direct laser writing (DLW), as already described for similar material measures elsewhere [7] The arrangement of the individual material measures onto the sample is illustrated in Figure 7 by displaying the design model. The single structures are aligned in a row, so that a measurement of all profile-based geometries is possible with one profile scan.…”

Shape deviations of DLW microstructures in dependency of fabrication parameters

“…Among other applications micro optics [5][6][7], cell scaffolds [8][9][10] and microfluidics [11,12] have been described in the literature. Shape deviations or surface variances are a drawback for roughness calibration structures as described by Ströer and Eifler [13,14]. To improve repeatability and find a way towards producing reliable standard structures one has to be able to predict the expected discrepancies in the shape of the final structure based on the selected fabrication parameters.…”