Patent ID: 8356713

Claim:
A retainer comprising: a frame comprising a pair of opposing parts that are opposed to each other, and a bridging part that bridges the pair of opposing parts; a pair of first elastic parts, which are projected from one and the other of the pair of opposing parts of the frame, respectively, wherein free ends of the pair of first elastic parts are directable toward a substrate, the pair of first elastic parts being bent in an elongated, approximate L-shape, and are formed to be arranged substantially parallel to the bridging part; a second elastic part that bridges the free ends of the first elastic parts, wherein the second elastic part extends along a periphery of the substrate, thereby retaining the substrate; a pair of first holds arranged on the second elastic part so as to hold a rim of the substrate; and a pair of second holds, which are arranged at one and the other ends of the second elastic part, respectively, so as to hold a rim of the substrate, wherein the second elastic part is configured to be movable in a direction, which the second elastic part extends toward, due to movement of the substrate held by the second elastic part; wherein the second elastic part is configured such that an outer end of the second elastic part is disposed on an outer side of the free ends of the pair of first elastic parts; wherein each of the first holds is formed at a center-line side of the substrate while the second holds are formed on an outer-side edge of the second elastic part, respectively, with a space in-between, such that the first holds abuts the substrate earlier than the second holds so as to hold the substrate; wherein the second elastic part is formed so as to be supported between the free ends of the pair of first elastic parts and the other ends thereof are arranged to be positioned outside, and close to, the respective opposing parts than the free end, and a middle portion of the second elastic part is supported by the free ends; wherein two projections are formed at each of the first holds such that one is higher and the other is lower, and are formed asymmetrically with respect to the center line of the plane of semiconductor wafer; and wherein a projection and a holding groove are formed at each of the second holds such that the projection and holding groove are extended in the circumferential direction of the semiconductor wafer and are formed to be arranged on both outer ends to be positioned outside, and close to, the respective opposing parts than the free end of the first elastic part; and wherein the frame includes the pair of opposing parts arranged apart from, each other and a pair of second bridging parts supported at both ends between the paired opposing parts, and at least spring-like flexions and positioning portions are formed at least in either of the opposing parts or the bridging parts.