Polymeric resins are playing an increasingly important role in the packaging technologies are being develop for next generation semiconductor devices (1).  The push towards the heterogenous integration of multiple components, including arrays or stacks of semiconducting chiplets, high bandwidth memory elements, silicon interposers, electrically conducting copper vias or solder bumps onto a circuit board or substrate demands the use of polymeric resins that can reliably hold these disparate elements together into a high-performance semiconductor device.  In the classic example of a packaging material, such as an encapsulant, adhesive, underfill or a molding compound, the primary function of the packaging resin was to hold the device components in place.  These materials were traditionally epoxies, silicones or polyimides that could be dispensed as a liquid or semi-soft solid that could flow into place and then react to form a rigid package.  However, with the deep integration strategies that are currently being pursed, the demands on the packaging materials are increasing.  In addition to flowing into place and reacting, they must mitigate the cure induced shrinkage stresses that are generated.  They must manage the coefficient of thermal expansion mismatch that are generated during operation of the device that can create stresses and lead to failure.  They must resist deterioration over the environmental stresses induced by absorbed water, temperature gradients and cycling electric fields.  And they must provide dielectric insulation to reduce electrical cross-talk between the different components and maintain low dielectric constants and loss properties under their harsh operational conditions at the switching speeds that are relevant for 5G and 6G technologies.  Under this research opportunity, we seek applicants who develop measurements and materials for the processing of the next generation packaging resins and help establish the structure-processing-property relationships that are critical to realize improved packaging resins.  These include quantifying the degree of chemical conversion and cure kinetics of the packaging resins as they cure, how the viscosity and cure induced stresses build up these systems, how these processes lead to warpage and distortion of the package, local measurements of potential heterogeneities of the mechanical and dielectric properties, and how all of these critical properties are affected by the relevant environmental stressor of temperature, relative humidity fluctuations and cycling electric fields.

References:

(1) “Material Needs and Measurement Challenges for Advanced Semiconductor Packaging: Understanding the Soft Side of Science” Ran Tao, Polette Centellas, Stian Romberg, Anthony Kotula, Gale Holmes, Amanda Forster, Christopher Soles, Robert Allen, Edvin Cetegen, William Chen, Jeffrey Gotro, and Mark Poliks, IEEE Transactions on Components, Packaging and Manufacturing Technology, (2025).  DOI: 10.1109/TCPMT.2025.3603484.

semiconductor packaging; packaging resins; underfills; encapsulants; molding compounds; adhesives; epoxy; silicones; polyimides; materials characterization; cure induced shrinkage; residual stress; coefficient of thermal expansion; spectroscopy; calorimetry; infrared spectroscopy; Raman spectroscopy; dielectric spectroscopy

citizenship

Open to U.S. citizens

level

Open to Postdoctoral applicants