Burn-in Testing of Semiconductors

Methods and specially adapted reusable test carriers allow for burn-in test of semiconductor integrated circuit devices and economical production of known good dice (KGD). Methods for temporary flip-chip mounting of IC wafers or dice use a hierarchy of solder melting points in conjunction with improved reusable carrier substrates. IC chip wafers having high-melting-temperature flip-chip terminals are coated with a predetermined level of a sacrificial solder having a significantly lower temperature that is melting.

A reusable carrier that is temporary provided, in a range of sizes adapted for a wafer, small variety of IC dice, or an individual die, For full-wafer burn-in, the reusable carrier has edge connector terminals. The reusable carrier has conductive elements in a pattern matching each IC dies terminal pattern for testing individual dice or a small number of dice. The exact same or opposite side of the reusable carrier has pins or ball-grid array matching a regular socket that is burn-in. A preferred reusable carrier consists of separable parts: a substrate customized to carry specific dice for burn-in, and a “universal” carrier package adapted to suit standard test sockets.

After burn-in testing, the known good dice are removed by a low-temperature reflow, and mounted on permanent substrates by conventional high-temperature reflow. The test carriers are re-usable after cleaning. A carrier structure just like the preferred structure that is separable specially adapted for testing and/or permanent packaging of IC chips which utilize wire-bond connections.

A semiconductor and an approach for simultaneously testing or burning in most the circuit that is integrated on a product wafer. The semiconductor comprises a glass ceramic carrier having test chips and opportinity for connection to pads of a large number of chips on an item wafer. Voltage regulators from the test chips provide an interface between a charged power supply and power pads in the product chips, at least one voltage regulator for every product chip. The voltage regulators provide a specified Vdd voltage into the product chips, whereby the Vdd voltage is substantially independent of current drawn by the item chips.

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