Papers by Keyword: Positive Photoresist

Abstract: NMP is a commonly used solvent for removing positive photoresist in 3D applications, especially in electroplating and (micro-) bumping. However, the negative photoresists are more and more preferred in these applications. Unfortunately, NMP is inefficient for negative photoresist and it is not considered in Europe as an ESH solvent anymore. In this paper a comparative study was carried out in order to identify a solvent that is ESH friendly and a one-size-fits-all solution for stripping negative-tone and thick positive-tone photoresist (2-22 μm) for (micro-) bumping, electroplating and TSV etch applications. The study was performed at tool level.

Abstract: Much of the recent ongoing advanced research into the quest for improved etching techniques has brought forth a broad concept for the fabrication of micro/nano-electromechanical systems (MEMS/NEMS) having high accuracy, precision, efficiency, compatibility and through-put of metallic- as well as carbon-composition structural phases. This in turn leads towards a thorough understanding of the sensing, trapping, separating, controlling, positioning, directing, concentrating and manipulating of micro-nano-sized particles - predominantly biological particles - in the emerging MEMS/NEMS technological field. This paper focuses its attention on the easiest means of wet-etching {100}-type silicon wafer surfaces by guiding the choice of [<100> or <010>] orientation (at 45° to the normal orientation). This anisotropic etching is performed in KOH solution. Here, consideration is not concerned to a large extent with process parameters as in anodic oxidation, an intensely doped boron etching stops and silicon wafer surface back-etching. The main concern of the present practical application route involves a passivating material (silicon dioxide, SiO2) and two masking stages (for a two-step etching process). As a example of this method, silicon cantilever beams having vertical edges are produced. It is concluded that the method presented will be helpful in the comprehensive study of resonators, pressure/temperature sensors, three-dimensional carbon micro-electrodes, actuators and accelerometers for bioparticle applications.

Abstract: The fabrication process of three-dimensional (3D) high-aspect-ratio MEMS devices entirely made of electroplated metals with suspending multilayered microstructures is reported. The technology used is a LIGA-liked micromachining process, called the laminated positive photoresist sacrificial layer process (LPSLP). The LPSLP allows in UV-lithography not only for thick resist mould for electroplating of cascaded metal structures but also for the sacrificial layer for supporting mechanically the suspensions. So far the LPSLP procedure has incorporated with more than five sacrificial layers, which allows for the creation of overhanging structures and freely moving parts like out-of-plane cantilever stacks. A description of the underlying fabrication principle and processing details is discussed in this paper. Thus the proposed procedures open a low-cost route for fabricating micro-components such as cantilevers, bridges, movable electrodes, and freestanding parts.