An Investigation of Processes for Glass Micromachining

Abstract

This paper presents processes for glass micromachining, including sandblast, wet etching, reactive ion etching (RIE), and glass reflow techniques. The advantages as well as disadvantages of each method are presented and discussed in light of the experiments. Sandblast and wet etching techniques are simple processes but face difficulties in small and high-aspect-ratio structures. A sandblasted 2 cm × 2 cm Tempax glass wafer with an etching depth of approximately 150 µm is demonstrated. The Tempax glass structure with an etching depth and sides of approximately 20 μm was observed via the wet etching process. The most important aspect of this work was to develop RIE and glass reflow techniques. The current challenges of these methods are addressed here. Deep Tempax glass pillars having a smooth surface, vertical shapes, and a high aspect ratio of 10 with 1-μm-diameter glass pillars, a 2-μm pitch, and a 10-μm etched depth were achieved via the RIE technique. Through-silicon wafer interconnects, embedded inside the Tempax glass, are successfully demonstrated via the glass reflow technique. Glass reflow into large cavities (larger than 100 μm), a micro-trench (0.8-μm wide trench), and a micro-capillary (1-μm diameter) are investigated. An additional optimization of process flow was performed for glass penetration into micro-scale patterns.

Fabrication of Vacuum-Sealed Capacitive Micromachined Ultrasonic Transducer Arrays Using Glass Reflow Process

“…After glass reflow, both sides of the silicon-glass wafer are mechanically lapped and polished by a chemical mechanical polishing (CMP) to achieve the mirror surfaces (Figure 3e). The complete filling process into silicon cavities has been investigated by optimization of the reflow conditions such as high temperature, long-running process and assistance of enhancement of the surface wettability presented in our recent research [17]. Mirror surfaces on the silicon-glass wafer have been achieved as shown in Figure 4a,b.…”

“…A clear cross-sectional image can be achieved if the polishing process performs after diamond cutting. The high density of through-wafer interconnects is possible by an investigation on glass reflow conditions as shown in [9,17]. Next, the silicon through-wafer interconnects have been etched at the depth of approximately 3 μm for making the capacitive gaps (Figure 3f).…”

Fabrication Technology of a Sensitive Element of Q-Flex Accelerometer by Volume Micromachining

“…В настоящее время существует несколько технологий микрообработки стекла, которые можно разбить на три группы: струйноабразивная обработка, ионное и химическое травление [3]. При изготовлении чувствительного элемента акселерометра необходимо обеспечить низкую шероховатость поверхности формируемых упругих перемычек, а также отсутствие повреждений данной поверхности, которые могут быть вызваны бомбардирующими ионами и абразивными частицами.…”

Glass Surface Decoration by Sandblasting Technique: A Case Study

“…Abrasive blasting is more of a general name for application of abrasives to material surfaces. Van Toan , Toda, & On, (2016) explained that glass micromachining on the other hand is a more specific name for application of varieties of abrasive designs on the surface of glass. These designs (treatment) could come in various colors and shapes and are used primarily to diffuse light, reduce glare and obtain a translucent and beautiful appearance on glass surface.…”

“…Sandblasting is like spray painting but instead of paint you blow an abrasive material with compressed air to etch the surface being blasted. A "resist" material is applied to the glass, the desired design is cut into the resist to produce a stencil, and the areas you want to be etched removed (Van Toan , Toda, & On, 2016). In other words, "Sandblasting can be referred to as a process where compressed air is mixed with abrasive media and shot at targeted areas of glass or mirror to etch a pattern, shape, or design of one's choice".…”