Method for testing a packaging substrate, and apparatus for testing a packaging substrate

An apparatus for testing a packaging substrate in accordance with the method for testing a packaging substrate (10) for multi-device in-package integration, with at least one electron beam column, the method comprising:

• placing the packaging substrate (10) on a stage (105) in a vacuum chamber (101);
• directing at least one electron beam of the at least one electron beam column on at least a first portion of the packaging substrate;
• directing the at least one electron beam of the at least one electron beam column on at least a second portion of the packaging substrate;
• detecting signal electrons emitted upon impingement of the at least one electron beam for testing a first device-to-device electrical interconnect path of the packaging substrate;
• and illuminating at least a third portion of the packaging substrate with UV radiation;
• and providing a reference potential via a conductive stage while illuminating the third portion with UV radiation.

An apparatus (100) for contactless testing of a packaging substrate (10) for multi-device in-package integration, comprising:

• a vacuum chamber (101);
• a stage (105) within the vacuum chamber, the stage being configured to support the packaging substrate and having a conductive stage surface connected directly or indirectly to ground for providing a reference potential;
• a charged particle beam column (120) configured to generate an electron beam, the charged particle beam column comprising:
• an objective lens (124) configured to focus the electron beam on the packaging substrate;
• a scanner configured to scan the electron beam to different positions on the packaging substrate;
• and an electron detector (140) for detecting signal electrons (113) emitted upon impingement of the electron beam on the packaging substrate;
• the apparatus further comprising:
• a UV source assembly configured to illuminate the packaging substrate in the vacuum chamber with one or more pulses of UV radiation while the reference potential is provided;
• and an analysis unit (141) for determining, based on the signal electrons (113), if a first device-to-device electrical interconnect path (20) is defective.