Apparatus for monitoring process chamber

A sensor assembly comprising:

• a sensor module configured to monitor a process status of a process chamber, the sensor module including,
• a cover section including a pinhole, the cover section having a first length in a direction toward a center of the process chamber,
• a sensor configured to monitor a first region at an interior of the process chamber determined based on the first length through the pinhole, and
• a main body including a fixing section and an insertion section, the fixing section configured to removably support the sensor, and the insertion section configured to be coupled to the cover section,
• wherein the sensor module is configured to be inserted into an inner wall of the process chamber.

A method for fabricating a semiconductor device, the method comprising:

• performing a plasma process on a substrate in a process chamber;
• monitoring, by at least one image pickup unit, a distribution status of a process substance in the process chamber, the at least one image pickup unit configured to change a monitoring region in the process chamber by adjusting a focal distance thereof;
• and
• obtaining, by at least one processor, a density distribution of the process substance in the process chamber, by performing at least one arithmetic operation using monitoring results from the at least one image pickup unit;
• wherein the at least one image pickup unit is configured to be inserted into an inner wall of the process chamber.