US 12,264,914 B2
Device and method for measuring wafers
Stephan Weiß, Rodgau (DE); Simon Mieth, Frankfurt am Main (DE); Corinna Weigelt, Langen (DE); and Tobias Beck, Heusenstamm (DE)
Assigned to PRECITEC OPTRONIK GMBH, Neu-Isenburg (DE)
Filed by PRECITEC OPTRONIK GMBH, Neu-Isenburg (DE)
Filed on May 23, 2024, as Appl. No. 18/673,052.
Application 18/673,052 is a continuation of application No. PCT/EP2023/051737, filed on Jan. 25, 2023.
Claims priority of application No. 10 2022 104 416.5 (DE), filed on Feb. 24, 2022.
Prior Publication US 2024/0310159 A1, Sep. 19, 2024
Int. Cl. G01B 9/02091 (2022.01); G01B 9/02055 (2022.01); G01B 11/06 (2006.01)
CPC G01B 9/02091 (2013.01) [G01B 9/02072 (2013.04); G01B 11/06 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A device for measuring wafers, the device comprising:
an optical coherence tomograph configured to generate a measuring light beam and to direct the measuring light beam onto a wafer via an optical system;
a scanning device configured to deflect the measuring light beam in two spatial directions;
a control unit configured to control the scanning device in such a way that the measuring light beam scans the surface of the wafer successively at a plurality of measuring points, wherein two measuring points have a distance dmax with 140 mm≤dmax≤600 mm; and
an evaluation unit configured to calculate distance values and/or thickness values from interference signals provided by the optical coherence tomograph,
wherein the scanning device has exactly two scanning mirrors, which are each mounted rotatably about exactly one axis,
wherein a spatial distance between the two scanning mirrors is no larger than is necessary to scan the wafer at the plurality of measuring points, and
wherein a collision protection device is configured to limit angles of rotation of at least one scanning mirror of the two scanning mirrors to prevent the two scanning mirrors from colliding with one another.