US 6,982,418 B2
Contact hole standard test device, method of forming the same, method of testing contact hole, method and apparatus for measuring a thickness of a film, and method of testing a wafer
Keizo Yamada, Tokyo (Japan)
Assigned to Fab Solutions, Inc., Kanagawa (Japan)
Filed on Jun. 16, 2004, as Appl. No. 10/868,615.
Application 10/868615 is a division of application No. 09/451440, filed on Nov. 30, 1999.
Claims priority of application No. 10-340636 (JP), filed on Nov. 30, 1998; application No. 10-348988 (JP), filed on Dec. 08, 1998; and application No. 10-351928 (JP), filed on Dec. 10, 1998.
Prior Publication US 2004/0232331 A1, Nov. 25, 2004
This patent is subject to a terminal disclaimer.
Int. Cl. G01R 17/02 (2006.01)
U.S. Cl. 250—306 32 Claims
OG exemplary drawing
 
1. A system far detecting a residual material in one or more via holes disposed in a layer which is disposed on or above a wafer, the system comprising:
an electron gun to irradiate an electron beam on the one or more via holes;
a detector to measure a current at a back surface of the wafer, wherein the current is generated in response to the electron beam irradiated on the one or more via holes; and
a comparator, coupled to the detector, to determine the presence of the residual material in one or more of the one or more via holes using the amount of current measured by the detector.