Reticle pod having anti-collision gap structure
The invention discloses a reticle pod for receiving a reticle. The reticle pod includes a base and plural support device provided on the base for supporting the reticle. A first distance is defined between a peripheral area of a bottom surface of the reticle and an upward facing top surface of the base. A second distance is defined between a central area of the bottom surface of the base and the upward facing top surface of the base, wherein the central area is encircled by the peripheral area. The second distance is larger than the first distance.
1 . A reticle pod for receiving a reticle, the reticle pod comprising:
a base, having a support surface and an upward-facing top surface surrounded by the support surface, the support surface extending around the base; and
a plurality of support devices disposed on the base to support the reticle when the reticle is received in the reticle pod, with a first distance defined between a peripheral area of a bottom surface of the reticle and the upward-facing top surface of the base, and a second distance defined between a central area of a bottom surface of the reticle and the upward-facing top surface of the base, wherein the central area is surrounded by the peripheral area, and the second distance is greater than the first distance;
wherein each of the support devices has a support pin and two positioning elements, and a corner of the reticle is positioned in place by the two positioning elements;
wherein the upward-facing top surface of the base faces the reticle and has planarity of less than 0.06 mm.
2 . The reticle pod of claim 1 , wherein the first distance ranges from 0.18 mm to 0.30 mm.
3 . The reticle pod of claim 1 , wherein the second distance is greater than 1.50 mm.
4 . The reticle pod of claim 1 , wherein when the reticle is received in the reticle pod, the first distance is the shortest distance between the peripheral area of the bottom surface of the reticle and the upward-facing top surface of the base, and the second distance is the shortest distance between the central area of the bottom surface of the reticle and the upward-facing top surface of the base.
5 . The reticle pod of claim 1 , wherein when the reticle is received in the reticle pod the central area of the bottom surface of the reticle at least includes a pattern area of the reticle.
6 . The reticle pod of claim 1 , wherein the upward-facing top surface of the base has a deflection surface caused by a low frequency factor from mechanical processing.
7 . The reticle pod of claim 1 , wherein the peripheral area has an outer edge and an inner edge and extends therebetween, and a distance less than 5 mm is defined between the outer edge and the inner edge.