Microelectronics

The Delphi PST series of Thermal Test Die is used to determine thermal characteristics of a package, such as thermal resistance Junction to Case (Θ jc) or Junction to Ambient (Θ ja). These Thermal Test Die incorporate a heating element and typically, two independent methods for on-die temperature monitoring.

Resistive heating in the PST6 is accomplished by driving a current through a doped silicon well between a pair of bus bars, labeled Rs and Rf. The 4 R labeled pads accommodate Kelvin connections, if desired.

At the top and bottom of the die are a pair of pads, labeled D in the diagram, which connect a serial five-diode temperature sense network. Again, a four-pad layout allows Kelvin connections, if desired. A second temperature monitoring circuit uses a bridge network by connecting the "V" at the top of the die and the "G" at the bottom of the die with one sense pin "S" at the top of the die and the other sense pin "S" at the bottom of the die.

The PST6 incorporates a feature not found on some of the smaller PST die (PST1 to PST3). The five-diode string from the center is duplicated in all four corners. The corner diode strings are connected in series such that each corner can be monitored individually while driven by a single current source. Numerous pads (labeled S) can be used to sense the diode voltage.

Options Available

• Five-inch wafer, no bumps, nitride passivation, 182-micron square passivation openings for wire bonding

IC Fab Information