Texas Instruments Corporation

Cheryl Diane Hartfield

Thomas M Moore

Darvin R Edwards

Jerry J Broz

Reynaldo M Rincon

Daniel Joseph Stillman

Nancy R Ota

In a method and system for evaluating sub-critical fatigue crack growth in a semiconductor device, a plurality of energy pulses generated by an energy source are repeatedly impinged onto the semiconductor device for a predefined time interval. The repeated impinging of the plurality of energy pulses induces a mechanical stress within the semiconductor device. The induced mechanical stress, maintained below a threshold and repeated for a predefined number of cycles, causes a formation of a sub-critical fatigue crack within the semiconductor device. A detector detects the presence of the sub-critical fatigue crack leading to a fatigue failure. A rapid determination of a pass or fail status for a fatigue test of the semiconductor device is made by comparing a total number of cycles to fatigue failure to a predefined benchmark.

Rapid method for sub-critical fatigue crack growth evaluation

One embodiment of the invention is a method for evaluating a material such as low-k dielectric, by a stress-generating test tool such as a needle. The evaluation object is shaped as a stack of adhering layers: low-k dielectric, first metal (preferably copper), barrier metal (preferably tantalum nitride), and second metal (preferably aluminum). A numerical correlation is established between a cracking in the barrier metal layer caused by probing and a damage in the layer of insulating material-to-be-tested. A predetermined number of locations of the top metal layer is selected for the probing step comprising touch-down, applying force, and lifting is repeated so that the number of repeats provide a pre-determined statistical confidence level. The top metal layer is then removed by a chemical etch solution so that the etch solution also penetrates into any stress-created cracks of the barrier metal layer underneath the imprints, and further dissolves a portion of the first metal layer, generating cavities in the first metal layer. The occurrence of all first metal cavities is recorded and correlated with the probing.

Statistical method for identifying microcracks in insulators

An apparatus ( ) and method ( ) for predicting electrical property stability of a thin film or conductive substrate ( ) prior to multi-probe testing. The present invention utilizes a nanoindenter type device ( ) obtaining mechanical properties as a function of displacement depth and applied load into the bond pad surface to accurately predict electrical property stability of the entire substrate or sample under test. In addition, the present invention includes a nanoindenter type device ( ) including a second probe ( ) having the ability to measure localized electrical properties of the sample while obtaining the mechanical property measurements. This additional electrical measurement is correlated with the mechanical property measurements to accurately predict electrical property stability of the entire conductive substrate, preferably by predicting the presence of an unwanted material surface layer.

Combined electrical test and mechanical test system for thin film characterization

A method for reworking integrated circuit (IC) wafers having copper-metallized bond pads covered by deposited layers of a barrier metal and a bondable metal. After identifying the wafers with off-spec metal layers, the wafers are chemically etched using selective etchants consecutively until the metal layers over the bond pads are removed without damaging the copper metallization. Replacement metal layers are finally deposited over the bond pads. Specifically, the bondable metal, such as gold, is selectively removed by a cyclic dithio-oxamine compound, dissolved in tetra-hydro-furane or acetone. The barrier metals, such as nickel and palladium, are removed by a mixture of inorganic and organic oxidizing acids.

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McKinney, TX, United States of America

Cheryl Diane Hartfield