Patterning and Reactive Ion Etching of Diamond Films using Light Coupling Masks
- PDF / 835,608 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 57 Downloads / 216 Views
R5.2.1
Patterning and Reactive Ion Etching of Diamond Films using Light Coupling Masks Patrick W. Leech1, Geoff K. Reeves and Anthony S. Holland, School of Computer Systems and Electrical Engineering, RMIT University, Victoria, Australia. 1 CSIRO Manufacturing and Infrastructure Technology, Clayton, 3169, Victoria, Australia.
ABSTRACT We describe the novel application of light coupling masks (LCM) in the lithographic patterning of fine structures in diamond films. A PDMS mask was used in the exposure of complex patterns of gratings in AZP 1205 resist on a substrate of Al/ diamond. The profiles of these grating patterns were then modified on a localized scale by a process of reflow of the resist. We report on the transfer of the patterns formed in resist by the LCMs into the diamond film using a sputtered Al layer as a mask. The two-stage process comprised etching of the pattern into the Al followed by transfer into the diamond film using CF4/ O2 and CHF3/ O2 gases. The presence of O2 in the CF4/ O2 and CHF3/ O2 gas mixtures produced Al oxides on the surface of the mask. The etch selectivity of the mask was greater in CF4/ O2 than in CHF3/ O2 gases and was only weakly dependent on the concentration of O2 (0-12 sccm). INTRODUCTION The unique properties of diamond have encouraged its application in devices such as ultralow friction MEMs [1] and chemically inert biochemical reactors [2]. The realisation of many of these devices depends on the development of techniques for patterning and etching of the diamond. The standard method used for the patterning of resist-coated wafers of diamond/ Si has been contact lithography with a Cr/ quartz mask. However, the high level of force between the mask and wafer in maximum-resolution patterning has introduced the risk of damage to the contacting surfaces. As a consequence, the technique of projection lithography has been increasingly used for the patterning of high-resolution features despite the requirement of a complex system of optics. The recent introduction of light coupling masks (LCMs) has combined the simple methodology of contact lithography with the advantages of conformal patterning over large areas at low force [3,4]. The LCMs have comprised a flexible elastomer with a relief pattern moulded into the surface. The elasticity of the LCMs has allowed the protruding microfeatures to form an intimate contact with the substrate and create modes of localised optical transmission or light guiding [3]. Areas of light blocking in the LCMs were formed at recessed micro-features which retained an air gap under the conformal force and produced regions of multiple light reflection [3]. The flexible properties of the LCMs have provided the advantage of fabrication of patterns on curved surfaces [4] such as the types of components which may be potentially coated with a diamond film. In this paper, we describe the novel application of LCMs in the patterning and subsequent reactive ion etching of diamond films. This study has examined the initial patterning with an LCM and the subseq
Data Loading...
