All or a part of the thin films such as the silicon film, insulation film and conductive film are formed using liquid materials. The apparatus comprises a bonding roll comprising a base surface and plurality of nubs extending from the base surface, each of the plurality of nubs comprising: a sidewall; a bonding surface; and a shoulder connecting the sidewall to the bonding surface. The embodiments therefore are significant for various communication transmitters to achieve simple structure, good linearity and high power efficiency. The upper portion includes a foot section fixedly coupled to the sole portion and a leg section extending upwardly from the foot section.