Abstract: A high frequency semiconductor device includes: a substrate having a substantially flat principal surface, with a predetermined circuit pattern including at least an input line, an output line, and a ground electrode provided on the principal surface; and a transistor which has a drain electrode, a source electrode, and a gate electrode and is mounted on the substrate by a flip chip mounting. The source electrode and the ground electrode are connected to each other by a first bump in the flip chip mounting.

Abstract: An optical information apparatus for performing at least one of a reproduction operation and a recording operation for an information medium by radiating a light beam on the information medium is provided, wherein the information medium has a first region, including a first track having information recorded thereon in the form of convex and concave pits, and a second region, including a second track formed in the form of convex and concave guide grooves.

Abstract: A method and apparatus for planarizing works can adjust an urging force or pressure applied to a work with ease in a short period of time, but also avoid wasteful use of rings. Wafers 100 adhered to a block 110 is made into contact with a lower surface plate 1. An annular ring 5 which encloses the wafers 100 is disposed in the peripheral portion of the block 110. The peripheral portion of the block 110 is pressed by a head 4 through an annular ring 5. Simultaneous with this, by rotating the lower surface plate 1 while pressing the central portion of the block 110 at a desired pressure by means of a center-pressing member 6 provided on the head 4, the wafers 100 are planarized.