公开(公告)号：FR2355275A1

公开(公告)日：1978-01-13

申请号：FR7714011

申请日：1977-05-03

Applicant: IBM

Inventor： JARISCH WALTER ,  MAKOSCH GUNTER ,  SCHACKPEFFER ARNO

IPC: G01B11/00 ,  G01B9/02 ,  G01B11/24 ,  G01B11/30 ,  G01N21/956

Abstract: Disclosed is an interferometric apparatus and method for the inspection and detection of overlay errors characterized in that two plane polarized laser beams are directed onto the surface to be inspected, the angle included by these two beams being dimensioned in such a way that the radiation generating the plus or minus first order of the diffraction pattern of one beam is parallel to the other beam, thus generating an interference field which in the absence of overlay errors consists of an homogeneous fringe pattern while in the presence of such errors the fringe pattern is locally distorted. In a first embodiment, a first component of a laser beam is deflected onto a viewing screen by a beam splitter while a second component passes through the beam splitter to a mirror. The position and angle of the mirror is determined by the first order diffraction characteristics of the grating (object). The second component provides a first order of diffraction which interferes with the first component, producing an interference pattern on the viewing screen.

公开(公告)号：CA974112A

公开(公告)日：1975-09-09

申请号：CA149058

申请日：1972-08-09

Applicant: IBM

Inventor： SCHMACKPFEFFER ARNO ,  FROSCH ALBERT ,  JARISCH WALTER ,  ZILLER JORG

IPC: G03H1/04 ,  G03H1/00

Abstract: A method is described for making holograms by means of linearly polarized object and reference beams, the reference beam being reflected inside the photosensitive emulsion. The plane of polarization of a linearly polarized reference beam includes an angle of 45 DEG with its plane of incidence. The beam is reflected under the critical angle of total internal reflection at the lower face of a photographic emulsion. The reflected beam is linearly polarized, too, its plane of polarization being turned by 90 DEG , so that no interference between these two beams is possible. An object beam passes a mask and is linearly polarized vertically either to the reference beam or to the reflected beam so that only one hologram can be formed and no undesired interaction between two holograms is possible when the mask is reproduced for exposure of a photoresist-covered semiconductor wafer.