Electrodepositable resists principles

Electroless deposition as we know it today has had many applications, e.g., in corrosion prevention [5-8], and electronics [9]. Although it yields a limited number of metals and alloys compared to electrodeposition, materials with unique properties, such as Ni-P (corrosion resistance) and Co-P (magnetic properties), are readily obtained by electroless deposition. It is in principle easier to obtain coatings of uniform thickness and composition using the electroless process, since one does not have the current density uniformity problem of electrodeposition. However, as we shall see, the practitioner of electroless deposition needs to be aware of the actions of solution additives and dissolved O2 gas on deposition kinetics, which affect deposit thickness and composition uniformity. Nevertheless, electroless deposition is experiencing increased interest in microelectronics, in part due to the need to replace expensive vacuum metallization methods with less expensive and selective deposition methods. The need to find creative deposition methods in the emerging field of nanofabrication is generating much interest in electroless deposition, at the present time more so as a useful process however, than as a subject of serious research. 

Following this introduction, the chapter continues with a description of the principles of electrodeposition (section 2.2). The various types of polymers employed in ED resist formulations are then described (section... 

Whilst there are some thermoset acrylic emulsions cormnerdally available, the bulk of the thermoset resins, used as the main binder system, are produced in solution. Some may then be made waterborne by neutralisation and inversion (dispersion) into a water phase. Lower molecular weights favour this qrproach. The rate of conversion from solvent based to waterborne industrial thermoset coating systems has been, and is, much slower than the conversion from architectural alkyd paints to emulsion altonatives. There are two principle reasons for this. Firstly there are problems of application and substrate wetting of many waterborne systems. Secondly, the modifications frequently required to induce water dispersibility reduce one or more of the essential performance properties required from the cured film, compared to a solvent based system. Water resistance, with many films having an increased tendency for blushing is one example. However, for some applications, such as electrodeposition, only waterborne systems will work. 

---