A semiconductor device or other suitable substrate and method with single or multi layers of buried micro pipes are disclosed. This is achieved by controlling the aspect ratio of trenches as well as controlling the deposition characteristics of the material used to fill the trenches. A buried micro pipe is formed by filling a trench that has a height which is larger than a width thereof, so that the trench filler material lines sidewalls and bottom of the trench, and covers the top of the trench to form the micro pipe within the trench. Another layer can be formed over the filler material and planarized. Alternatively, the filler material itself can be planarized. Forming trenches in the planarized layer, and repeating the above steps forms a second set of buried micro pipes in these new trenches. This forms a semiconductor device having multiple layer of buried micro pipes. Via holes may be etched to contact a micro pipe, or to inter connect micro pipes buried at different levels. Thus, instead of eliminating defective voids in trenches, the voids are controlled to form the micro pipes, which may be used to circulate a cooling fluid, or lined with a conductive material to form a micro light pipe channel, or buried conductive pipes.