Area-selective deposition

The potential benefits of CVD over other film deposition techniques are that CVD-derived films can be deposited under conditions that give conformal coverage, they can be deposited at low temperatures, there can be a high level of compositional control, thin layers can be deposited, the technique can be scaled to coat large areas uniformly, and there is also the possibility for area-selective deposition as a result of the chemical nature of this process. The details of CVD and related chemical deposition processes such as atomic layer epitaxy (ALE), organometallic vapor-phase epitaxy (OMVPE), and others have been described elsewhere. ... 

Area-selective deposition of such polymers is important as... 

Here, we ta)ce polypyrrole as an example and discuss the area-selective deposition process. 

Before discussing the area-selective deposition of polypyrrole, photoelectrochemical (not area-selective) deposition of polypyrrole should be discussed. Polypyrrole was first deposited on a semiconductor electrode in order to protect it from photodecomposition (20-23). However, the Importance of the area-selective deposition was not pointed out there. 

Figure 1 suggested the possibility of area-selective deposition of... 

Another way to functionalize depositions, is to entrap functional molecules in polypyrrole. Incorporation of functional molecules during electrochemical polymerization and the application of so prepared films to sensors have been studied by many workers (27). By means of area-selective deposition much more complicated functional depositions can be prepared on an electrode. The authors have shown that organic dyes (an example of functional molecules) are incorporated in the process of... 

When a photooxidative deposition occurs on semiconductor surfaces without any applications of external bias, a reduction reaction takes place simultaneously as the counterpart reaction (see Chapters). Irradiation of p-Si wafers in a zinc (Zn) or cadmium (Cd) salt solution resulted in area-selective deposition of metals on the irradiated part if the back surface of... 

In addition to forces in the surface normal direction, lateral, ie, friction, forces have been ntilized to detect area-selective deposition of polyelectrolytes (224), to... 

In addition to forming continuous organometallic multilayer thin films, we explored the LbL deposition of polyferrocenylsilane polyions onto, for instance, hydrophilically/hydrophobically modified substrates with the aim of building two-dimensionally patterned organometallic multilayers. In general, surfaces modified with microscopically patterned conducting, luminescent, or redox-active polymer films have potential use in microelectronic and optoelectronic devices and microsensor arrays. Area-selective deposition of polyferrocenylsilane polyions can be an attractive method to obtain two-dimensionally patterned redox active films, which may be used as electrochemically modulated diffraction gratings. ... 

Patterned organometallic multilayers may be of interest also as etch barriers in RIE processes. For this purpose it is essential that these films can be fabricated from etch resistant organometallic polyferrocenylsilane chains only, as organic polymers offer no resistance to reactive ion etching. This chapter deals with the formation of continuous organometallic multilayer thin films, and with the fabrication of patterned organometallic thin films, formed by area-selective deposition of organo-metaUic polyions on prepattemed substrates. 

The blanket deposition is then sputter etched through a resist to pattern the metallisation. Selective deposition of W, under development, would deposit metal only in desired areas, and would reduce process steps and costs. 

CVD processing can be used to provide selective deposition on certain areas of a surface. Selective tungsten CVD is used to fill vias or holes selectively through siUcon oxide layers in siUcon-device technology. In this case, the siUcon from the substrate catalyzes the reduction of tungsten hexafluoride, whereas the siUcon oxide does not. Selective CVD deposition can also be accompHshed using lasers or focused electron beams for local heating. 

Chen R, Bent SF (2006) Chemistry for positive pattern transfer using area-selective atomic layer deposition. Adv Mater 18 1086... 

Additive Approach. In the additive approach (Figure 18), a negative image of the conductor pattern is defined in a photoresist layer that must be thicker than the conductor layer. Metal is then selectively deposited in the open areas of the resist by electroplating or by a lift-off technique. For... 

Fig. 13 Selective deposition (A) continuous Pt thick film area (B) discontinuous Pt thick film area.

Selective deposition in PEVD is clearly indicated in Figure 13. As discussed previously, this is because of the unique feature of the electrochemical reaction for deposition. As schematically shown in Figure 18, the only area to meet the requirement for nucleation is the three phase boundary (point O) of Na -P"-alumina, Pt and gaseous phase, where Na, e and gaseous phase reactants (CO + O ) are all... 

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