Patent ID: 9097515
Filing Date: 2015-08-04
Classification: G01B,H01L

Abstract:
1. A measuring device comprising: a housing having an opening configured to receive a substrate that is carried in the housing along a carry-in path, the opening being disposed on one side of the housing; a first sensor disposed on an inner surface of the housing, the first sensor including a first light output part configured to emit a first light to the substrate and a first light receiving part configured to sense the first light reflected from the substrate; a second sensor including at least one second light output part configured to emit a second light and at least one second light receiving part configured to sense the second light, wherein the at least one second light output part and the at least one second light receiving part are disposed on opposite inner surfaces of the housing with the carry-in path of the substrate disposed between them such that the second light is blocked from the at least one second light receiving part by the substrate; and a controller, wherein, when a substrate is carried in the housing, the controller is configured to: calculate a vertical displacement of the substrate using the first light reflected from the substrate, to calculate a horizontal displacement of the substrate using the second light blocked by the substrate, and to calculate a displacement error based upon the time when the substrate blocks the second light to the time when the substrate is at a predetermined desired carry-in position of the substrate, wherein the displacement error is calculated using the vertical displacement and the horizontal displacement.