The present invention provides a silicon wafer sliced from a silicon single crystal ingot grown by the Czochralski method under such conditions that V-rich region should become dominant, wherein count number of particles having a size of 0. At least two alignment marks are formed in or on the top passivation layer to provide topological features for location of the hidden areas. The drum 6 is provided around its rotating shaft 8 with rotatable members 7 adapted to rotate in synchronization with the drum 6 in the direction in which the drum 6 rotates. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings. A method of producing reinforced articles comprising this reinforced protrusion is also disclosed. Where the heat generating conditions are generated by a heat generator, separate and distinct from the heat sensitive device, the boric acid may be supported in a position between the heat sensitive device and the heat generator.