Substrate inspection apparatus

A substrate inspection apparatus comprising:

• a stage configured to receive a substrate;
• a housing provided over the stage;
• an electron gun disposed in the housing and configured to emit an electron beam onto the substrate;
• an objective lens disposed under the electron gun in the housing and configured to adjust a focus of the electron beam;
• a deflector provided between the electron gun and the objective lens and configured to deflect a path of the electron beam;
• a first electron detector disposed on one side of the housing and configured to generate a first analog signal based on a result obtained by detecting secondary electrons emitted from the substrate by the electron beam;
• a signal converter connected with the first electron detector and configured to convert the first analog signal into a first digital signal;
• a signal generator connected with the signal converter and the deflector and configured to generate a reference signal to control operation of the signal converter and the deflector;
• a computing system connected with the signal converter and configured to obtain a pattern image for patterns of the substrate;
• and
• a delay generator connected between the signal generator and the signal converter and between the signal generator and the deflector,
• wherein the delay generator is configured to transfer a delayed reference signal to the signal converter and the deflector.

A substrate inspection apparatus comprising:

• a stage configured to receive a substrate;
• a housing provided over the stage;
• an electron gun disposed in the housing and configured to emit an electron beam onto the substrate;
• an objective lens disposed under the electron gun in the housing and configured to adjust a focus of the electron beam;
• a deflector provided between the electron gun and the objective lens and configured to deflect a path of the electron beam;
• a first electron detector disposed on one side of the housing and configured to detect secondary electrons emitted from the substrate by the electron beam;
• a second electron detector disposed between the housing and the stage and configured to detect backscattered electrons scattered from the substrate by the electron beam;
• a signal converter connected with the first electron detector and the second electron detector;
• a signal generator connected with the signal converter and the deflector and configured to generate a reference signal having a constant period to control operation of the signal converter and the deflector;
• a computing system connected with the signal converter and configured to obtain a pattern image for patterns of the substrate;
• and
• a delay generator connected between the signal generator and the deflector or between the signal generator and the signal converter,
• wherein the computing system generates an error correction graph by analyzing sample test images obtained by repeatedly photographing patterns of one area of the substrate,
• wherein the computing system stores pixel shift values of inspection images for inspection of the patterns of the substrate based on the error correction graph, and
• wherein the delay generator is configured to generate delayed reference signals corresponding to the pixel shift values.