News Article
Sonoscan announces advanced thickness measurement method
Using the echoes from the top and the bottom of a layer, the company achieves accurate measurements of the thickness of the bondline.
In a joint effort with a large component supplier to the cellular and video industries, Sonoscan has developed an acoustic micro imaging technique that accurately measures the thickness of the bondline of the heat spreader adhesive in advanced microprocessor assemblies, even when the bondline is so thin that individual echoes cannot be separated.
Internal thicknesses are typically measured by recording the time of an echo from the top of a layer and from the bottom of the same layer. The thickness of the bondline must be within a specific range (30 microns and 80 microns, for example) to avoid a loss of heat dissipation and consequent electrical failure.
These dimensions are too thin for the relatively low acoustic frequencies used to penetrate the metal heat spreader. The waveforms of the two echoes merge into a single echo.
The solution is to use one echo from the bondline itself and a second reference echo to extract the thickness measurements needed.
This new technique is being used with Sonoscan’s automated FACTS2 system, which carries trays of microprocessor assemblies. Bondline thickness measurements are taken at multiple points on each assembly in order to identify a process drift as soon as possible after attachment of the heat spreader.
Internal thicknesses are typically measured by recording the time of an echo from the top of a layer and from the bottom of the same layer. The thickness of the bondline must be within a specific range (30 microns and 80 microns, for example) to avoid a loss of heat dissipation and consequent electrical failure.
These dimensions are too thin for the relatively low acoustic frequencies used to penetrate the metal heat spreader. The waveforms of the two echoes merge into a single echo.
The solution is to use one echo from the bondline itself and a second reference echo to extract the thickness measurements needed.
This new technique is being used with Sonoscan’s automated FACTS2 system, which carries trays of microprocessor assemblies. Bondline thickness measurements are taken at multiple points on each assembly in order to identify a process drift as soon as possible after attachment of the heat spreader.
