Method for the thermal characterization of semiconductor packaging systems

A method for measuring the thermal characteristics of a packaging system for semiconductors comprising:

• providing a resistor comprising a substrate having a layer of platinum deposited thereon;
• mounting said resistor within a package designed for the containment of a semiconductor device;
• thermally calibrating said resistor within said package by subjecting said resistor within said package to at least two different temperatures, determining the resistance of said resistor at each of said temperatures, and generating a mathematical correlation between temperature and resistance for said resistor using said temperatures and resistances corresponding thereto;
• connecting said resistor to a test circuit having a voltage source therein;
• determining the voltage across said resistor;
• determining the resistance of said resistor during the operation of said circuit by measuring the current through said resistor, and dividing said voltage across said resistor by said current;
• using said mathematical correlation to obtain a temperature value corresponding to said resistance of said resistor during the operation of said circuit, said temperature value representing the temperature at the surface of said resistor during its operation;
• selecting a reference point on the outside of said package;
• measuring the temperature at said reference point during the operation of said circuit;
• and
• calculating the temperature gradient between the surface of said resistor and said reference point.

A method for measuring the thermal characteristics of a packaging system for semiconductors comprising:

• providing a package designed for the containment of a semiconductor device;
• providing a resistor sized to approximate the dimensions of the semiconductor device for which said package was designed, said resistor comprising a silicon substrate having a layer of platinum deposited thereon at a thickness of about 7,000 to 10,000 Angstroms;
• mounting said resistor within said package;
• thermally calibrating said resistor within said package by subjecting said resistor within said package to at least two different temperatures, determining the resistance of said resistor at each of said temperatures, and generating a mathematical correlation between temperature and resistance for said resistor using said temperatures and resistances corresponding thereto;
• connecting said resistor to a test circuit having a voltage source therein;
• determining the voltage across said resistor;
• determining the resistance of said resistor during the operation of said circuit by measuring the current through said resistor, and dividing said voltage across said resistor by said current;
• using said mathematical correlation to obtain a temperature value corresponding to said resistance of said resistor during the operation of said circuit, said temperature value representing the temperature at the surface of said resistor during its operation;
• selecting a reference point on the outside of said package;
• measuring the temperature at said reference point during the operation of said circuit;
• and
• calculating the temperature gradient between the surface of said resistor and said reference point, said gradient being calculated according to the expression:
• ##EQU9## wherein I.sub.j =the temperature at the surface of said resistor
• T.sub.c =the temperature at said reference point
• I=the current through said resistor
• V=the voltage across said resistor
• T.sub.jc =the temperature gradient in .degree.C./watt between said surrace of said resistor and said reference point