Wafer-level burn-in oven

An oven for wafer level burn-in testing of electronic wafers comprising;

• (a) an oven unit including a chamber defining a chamber environment;
• (b) a cascade heat control system comprised of a first heat transfer circuit for providing a heat transfer gas to a wafer chuck module and a second heat transfer circuit for providing a heat transfer gas to the chamber environment, the two circuits being connected by a pressure release conduit having a first venting valve for venting of heat transfer gas from the first heat transfer circuit into the second heat transfer circuit, and the second heat transfer circuit having a second venting valve for venting of heat transfer gas from said second circuit to the outside environment;
• and
• (c) at least one wafer chuck module including a test board and at least one wafer chuck for holding at least one electronic wafer for burn-in testing, and an inlet conduit and outlet conduit, the module being disposed within the chamber environment, and the module being in integral flow-through communication with the first heat transfer circuit and connected thereto by the inlet and outlet conduits.

A method of wafer level burn-in testing comprising:

• (a) providing an oven having:
• (i) an oven unit including a chamber defining a chamber environment;
• (ii) a cascade heat control system comprised of a first temperature control circuit for providing heat transfer gas to a wafer chuck module and a second temperature control circuit for providing heat transfer gas to the chamber environment, the two circuits being connected by a pressure release conduit having a first venting valve for venting of heat transfer gas from the first temperature control circuit into the second temperature control circuit, and the second temperature control circuit having a second venting valve for venting of heat transfer gas from said second circuit to the outside environment;
• and
• (iii) at least one wafer chuck module including a test board and at least one wafer chuck for holding at least on electronic wafer for burn-in testing, and an inlet conduit and outlet conduit, the module being disposed within the chamber environment, and the module being an integral part of the first temperature control circuit and connected thereto by the inlet and outlet conduits;
• (b) placing a electronic wafer into the wafer chuck;
• (c) circulating cooled inert gas through the first temperature control circuit to bring the temperature of the wafer to a target wafer test temperature;
• (d) circulating cooled inert gas through the second temperature control circuit to bring the temperature of the chamber environment to a target chamber test temperature;
• (e) maintaining the temperature of the wafer at the target wafer test temperature for the duration of the test and the temperature of the chamber environment at the target chamber test temperature for the duration of the test;
• and
• (f) providing the required test signals to the wafer for the duration of the test.

A method of wafer level burn-in testing comprising:

• (a) providing an oven having:
• (i) an oven unit including a chamber defining a chamber environment;
• (ii) a cascade heat control system comprising a first temperature control circuit for providing heat transfer gas to a wafer chuck module and a second temperature control circuit for providing heat transfer gas to the chamber environment, the two circuits being connected by a pressure release conduit having a first venting valve for venting of heat transfer gas from the first temperature control circuit into the second temperature control circuit, and the second temperature control circuit having a second venting valve for venting of heat transfer gas from said second circuit to the outside environment;
• and
• (iii) at least one wafer chuck module including a test board and at least one wafer chuck for holding at least on electronic wafer for burn-in testing, and an inlet conduit and outlet conduit, the module being disposed within the chamber environment, and the module being an integral part of the first temperature control circuit and connected thereto by the inlet and outlet conduits;
• (b) placing a electronic wafer into the wafer chuck;
• (c) circulating heated inert gas through the first temperature control circuit to increase the temperature of the wafer to a target wafer test temperature;
• (d) circulating heated inert gas through the second temperature control circuit to increase the temperature of the chamber environment to a target chamber test temperature;
• (e) maintaining the wafer of the wafer test target temperature for the duration of the test and the temperature of the chamber environment at the target chamber test temperature for the duration of the test;
• and
• (f) providing the required test signals to the wafer for the duration of the test.

An apparatus for burn-in testing of a semiconductor wafer comprising:

• (a) a housing for holding a semiconductor wafer, the housing having an upper portion and a lower portion which are connected so as to enable the upper portion to be moved relative to the lower portion between open and closed positions;
• (b) the upper portion of the housing having a heat exchanger that contacts the surface of a semiconductor wafer under test when the housing is in the closed position;
• (c) the heat exchanger having an inlet port and an outlet port through which a heat transfer gas for heating and cooling of a semiconductor wafer under test passes, the inlet and outlet ports being of sufficient size to permit the high volume flow of heat transfer gas through the heat exchanger;
• (d) the lower portion having a base adapted for connection to a test circuit board and a wafer support upon which a semiconductor wafer can be placed for burn-in testing, the wafer support, through the base, being in electrical communication with the test circuit board and capable of providing electrical connection between the semiconductor wafer and the test circuit board so that test signals can be received and transmitted.