SEMICONDUCTOR DEVICE IDENTIFICATION APPARATUS

摘要

A three-dimensional image of a semiconductor device identification pattern (1) is obtained by measuring the distance of at least one sensor (5) to the surface (2a) of said semiconductor device (2). The apparatus comprises a source of radiation (4); preferably a Laser, for deriving the distance from properties of the reflected light. A means for determining the distance (6) and an image processing unit (9) are used to establish the three-dimensional picture. Positional information can be achieved in a scanning movement from motors (7) being controlled by a control unit (8). By applying a threshold value, a two-dimensional image is derived and by means of a pattern recognition algorithm the identification pattern (1) can be analyzed in terms of, e.g., a semiconductor device identification. The apparatus advantageously solves the problem of discolorations due to previous processing in the case of semiconductor wafers, and is capable of addressing the problem of oxide layer obliteration of, e.g., Laser-engraved holes (3). Acoustic waves can alternatively be used as radiation. In this case the scanning method can be substituted by measuring runtime-differences from a set of fixed positions, and applying seismic reflection algorithms to recover a three-dimensional profile.