NOVELTY - A plasma processing apparatus (50) comprises a process chamber with second electrode, which exhibits a pattern of openings and is arranged at such a distance to a first electrode that a process gas delivered to gap (55) between the electrodes does not ignite plasma in the gap during operation. The distance between the first and second electrodes is 1-3 mm. The second electrode is designed as grounded plate (51) with a thickness of 1-15 mm.    USE - Plasma processing apparatus e.g. for deposition and/or etching, heating, and surface conditioning substrates including large area (greater than 1 m2) flat substrates, such as solar panels on glass, glass ceramics, plastic, and stainless steel; or further display panels for thin film transistor.    ADVANTAGE - The apparatus has improved (low energy) ion bombardment properties. It achieves plasma treatment of substrates with increased flexibility in terms of deposition rate, influence on crystallinity of deposited layers, and layer homogeneity. Lightweight, cost-effective, and scalable design of electrode is achieved for plasma processing apparatus. By disposing the grounded plate in vicinity to electrode, the plasma is forced to burn in the holes of the electrically grounded plate. This way localized plasma(s) can be generated. The spatial distribution of radicals produced in the burning localized plasma(s) and the ratio of grounded/powered electrode area can be adjusted by a proper design of the distribution of the holes, the holes'diameters, the shape of the holes, and their area density. This way, uniform layer with an excellent thickness uniformity and superior etch rate uniformity, respectively, can be achieved on substrate. The holes can be easily laser-cut, which eases variations of the diameter of the holes and avoids the efforts of drilling including the problem of drill-breakage. The RF voltage generates high bombardment directed onto the RF electrode and its corresponding ground connection and not to a floating electrode or substrate holder where substrate is placed and the soft deposition conditions occur. Thus, the deposition rate can be increased by using higher frequencies and/or higher voltages without risking damage to the substrate. In contrast to prior art design, where standing wave effect is partially avoided by complex electrical wiring and arrangement of segmented electrodes, the plasma processing apparatus allows to compensate it by the hole pattern design (i.e. diameter, arrangement, and density). This allows keeping the wiring simple, using only 1 or 2-4 connection points to one electrode, and at the same time the constructional and assembly efforts for the electrodes are minimized. It is possible to extend (scale up) the apparatus design to an arbitrary size (very large area reactors, greater than 3 m2) without an immense technological constructive effort.    DETAILED DESCRIPTION - A plasma processing apparatus (50) comprises a process chamber with process chamber walls (35), process gas inlet, process gas distribution mechanism, exhaust for removal of residual gases, first and second electrode arranged adjacent to each other thus forming a gap (55) between them, and radio frequency (RF) power source(s) (39) electrically connectable with the electrodes; and a substrate mount for a substrate (33) facing second electrode. The second electrode exhibits a pattern of openings and is arranged at such a distance to the first electrode that a process gas delivered to gap between the electrodes does not ignite plasma in the gap during operation. The distance between the first and second electrodes is 1-3 mm. The second electrode is designed as grounded plate (51) with a thickness of 1-15 mm.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of plasma processing apparatus.    Substrate (33)    Process chamber walls (35)    RF power source (39)    Plasma processing apparatus (50)    Grounded plate (51)    Gap (55)