Other

Super Silicon Crystal Research Institute Corp.

Sumitomo Heavy Industries, Ltd.

Kuroda Precision Industries Ltd.

Kohzo Abe

Nobuaki Iguchi

Yoshiyuki Tomita

Yutaka Koma

Hiroshi Nagata

Sho Isobe

Kazutoshi Hara

Ryuzo Masaki

Akio Iwase

A pair of optical profile measuring systems are located at positions facing to both surfaces of a wafer vertically supported at its edge. A thickness gauge having one or more sensors is located between the optical systems for measuring thickness at several points on the wafer . Each optical system comprises a light emitter for discharging a measuring light beam , a collimator lens for rectifying the light beam into a collimated beam, an optical flat for transmitting the collimated light beam , a light detector receiving the light beams reflected on a surface of the wafer and on a referential plane of the optical flat through the collimator lens and a computer for processing interference fringes which occur between the surface of the wafer and the referential plane of the optical flat . Profiles of main and backside surfaces of the wafer are calculated from interference fringes corresponding to both surfaces of a wafer , and a real shape of the wafer is determined from the profiles in consultation with thickness values measured by the thickness gauge

Optical instrument for measuring shape of wafer

Three columns are set up in an approximately triangle arrangement. A saddle , which fixes a main spindle thereto, is held in contact with a side face of the column or or a brace which unitarily connects two or three of the columns . A plurality of chucking tables are installed in an indexing table . When a work piece attracted onto one chucking table is carried to a position below the main spindle , the other chucking table is located at a loading-unloading position. Since the main spindle is located at a geometrical gravity center of a triangle defined by the columns , a reaction force which is generated during machining is uniformly distributed to each of the columns . Consequently, the columns are prevented from deformation which causes inclination of the main spindle , and the machined work piece has superior flatness.

Flattening machine

A double side grinding apparatus and a double side polishing apparatus, with a narrow tolerance range, reduces pitching errors, and ensures a sufficient level of rigidity against the force of reaction to machining, while enhancing positioning accuracy. The double side grinding apparatus or a double side polishing apparatus includes a plurality of guideways for supporting and shifting main spindles, and these plural guideways on end define a geometric center matched with the center of gravity of the main spindles. The number of the guideways is preferably three in order not to obstruct the mounting and removal of a workpiece.

Double side grinding apparatus and double side polishing apparatus

A pair of optical profile measuring systems 10, 20 are provided at positions faced to both sides of a wafer 1 vertically supported at its edge. Each system 10, 20 includes a light emitter 11, 21 for discharging a measuring light beam 12, 22, a collimator lens 14, 24 for rectifying the light beam 12, 22 into a collimated beam, an optical flat 15, 25 for transmitting the collimated light beam 12, 22, a light detector 16, 26 receiving the light beams 12, 22 reflected on a surface of the wafer 1 and on a referential plane of the optical flat 15, 25 through the collimator lens 14, 24 and a computer 17, 27 for processing interference fringes which occur between the surface of the wafer 1 and the referential plane of the optical flat 15, 25. Profiles of main and back surfaces of the wafer as well as its thickness variation are easily measured utilizing light interference fringes corresponding to both sides of a wafer.

Optical apparatus for measuring profiles of a wafer

Growing community of inventors

Annaka, Japan

Kohzo Abe