Electrical inspection of electronic devices using electron-beam induced plasma probes

A method for signal measuring from a structure under test having a conducting circuit by non-mechanical contact, the method comprising:

• providing an electron beam generator generating an electron beam inside a vacuum chamber;
• providing a membrane configured to preserve vacuum inside the vacuum chamber and to transmit the electron beam out of the vacuum chamber, and a conductor overlaying exit surface of the membrane;
• directing at least one electron beam through the membrane and the conductor so as to exit the vacuum chamber and focus on the conductive circuit, whereby the electron beam induces a plasma in gas existing between the conductor and the structure under test, where the electron beam passes through the gas, such that the plasma electrically contacts the conducting circuit of the structure under test and the conductor overlying the membrane;
• coupling a measurement device to the conductor to thereby electrically contact the plasma;
• and
• coupling a signal source to the conducting circuit of the device so as to form a conductive loop with the electrical measurement device, the conductor, the conducting circuit, and the plasma when the plasma is directed on the conducting circuit, so as to cause the electrical measurement device to respond to the signal source.

A method of fabricating a plasma probe for electrical measurement of a device under test, comprising:

• providing a vacuum enclosure having an orifice;
• affixing an electron source and electron lens inside the vacuum enclosure, the electron lens generating an electron beam and directing the electron beam through the orifice;
• affixing a membrane to the vacuum enclosure at the orifice, the membrane having a first surface facing interior of the vacuum enclosure and a second surface facing outside the vacuum enclosure;
• affixing a conductive film to overlay the second surface of the membrane;
• affixing a conducting contact to the conductive film;
• wherein,
• when the electron beam exits the orifice it generates plasma so that an electrical measurement device connected to the conducting contact detects an electrical signal through the plasma and the conductive film when the plasma is directed on a conducting circuit of the device under test.

A method for signal measuring from a device having a conducting circuit by non-mechanical contact, the method comprising:

• providing an electron beam generator generating an electron beam inside a vacuum chamber;
• providing a membrane configured to preserve vacuum inside the vacuum chamber and to transmit the electron beam out of the vacuum chamber, and a conductor overlaying exit surface of the membrane;
• directing at least one electron beam through the membrane and the conductor so as to exit the vacuum chamber and focus on the conductive circuit, whereby the electron beam induces a plasma in gas existing between the conductor and the device, where the electron beam passes through the gas, such that the plasma electrically contacts the conducting circuit of the device and the conductor overlying the membrane;
• coupling a signal source to the conductor to thereby electrically contact the plasma;
• and
• coupling a measurement device to the conducting circuit of the device so as to form a conductive loop with the signal source, the conductor, the conducting circuit, and the plasma when the plasma is directed on the conducting circuit, so as to cause the electrical measurement device to respond to the signal source.