Microelectronic fabrication etching

A case study on the operational improvement of a plasma etching unit in microelectronics fabrication ends the section. This case study illustrates that if similar preference structures are used in both types of formulation, identical final solutions are found when either categorical or continuous performance evaluation modes are employed. 

D microfabricated reactor devices are typically made by fabrication techniques other than stemming from microelectronics, e.g. by modern precision engineering techniques, laser ablation, wet-chemical steel etching or pEDM techniques. Besides having this origin only, these devices may also be of hybrid nature, containing parts made by the above-mentioned techniques and by microelectronic methods. Typical materials are metals, stainless steel, ceramics and polymers or, in the hybrid case, combinations of these materials. 

Chemical and chemical engineering principles involved in plasma-enhanced etching and deposition are reviewed, modeling approaches to describe and predict plasma behavior are indicated, and specific examples of plasma-enhanced etching and deposition of thin-film materials of interest to the fabrication of microelectronic and optical devices are discussed. 

On the other hand, deposition-based waveguides usually have a squarelike geometry in a strip, a strip-loaded or a rib configuration (Fig. 6). They are fabricated by depositing several layers onto a planar substrate by means of microelectronic processes, covering and etching them until the final geometry is obtained. 

The chemical dissolution of silicon can be obtained in both liquid and gaseous media. The latter is known as dry etching or reactive ion etching (RIE) and is used in today s microelectronic manufacturing. However, wet processes related to silicon are also very important, as one third of the total number of process steps for the fabrication of today s integrated circuits involve... 

Polymer/metal multilayer devices are used in the microelectronics industry. These devices are composed of alternating layers of polymer and metal, the metal is etched into lines and, except where via holes permit the contact of different metal layers, the polymer serves as an insulator. Because the polymer must withstand rather hostile environments during fabrication, the choice is narrowed to those which are stable to chemical treatment, high temperature (for short periods of time) and humidity. The polymers of choice here are the polyimides, although others are certainly used. 

The 64k, 80 pm x 80pm sized tilting mirrors are built on the top of a CMOS-based control ASIC. In order to reduce the topography of the underlying metallization/passivation structures, a 2.5pm-thick PECVD oxide film is first deposited on the ASIC. An ILD oxide CMP step based on Klebosol 30N50 colloidal silica slurry is used for planarization. In order to connect the ASIC with the deflection electrodes above (see Fig. 14.10), vias have to be etched into the planarized dielectric film. Then, a copper metal stack including a TaN barrier has to be deposited and a two-step Cu damascene CMP process has to be performed. As this process is equivalent to Cu damascene in microelectronics fabrication, standard Cu CMP slurries can be used. 

This leads us to another important category of multi-electron photoprocesses involving the semiconductor itself. While photocorrosion is a nuisance from a device operation perspective, it is an important component of a device fabrication sequence in the microelectronics industry. Two types of wet etching of semiconductors can be envisioned [290]. Both occur at open-circuit but one involves the action of chemical agents that cause the simultaneous rupture and formation of bonds. This is exemplified by the action of H2O2 on GaAs [291] ... 

In the past 15 years the field of micro-electromechanical systems (MEMS) has progressed tremendously thanks to the innovative utilization of the techniques of microelectronic fabrication. In particular, techniques of lithography using optical and electron beams and the development of anisotropic etching (both dry and wet) led to the rapid progress in the field. In recent years there have been new efforts to... 

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