Advanced Adhesion Strength Testing Methods of Thin Film Multilayers in Electronic Packaging Systems

With the continued miniaturization and increasing performance of electronic devices, new technical challenges have arisen. One such issue is delamination occurring at critical interfaces inside the device. This major reliability issue can occur during the manufacturing process or during normal use of the device. Proper evaluation of the adhesion strength of critical interfaces early in the product development cycle can help reduce reliability issues and time-to-market of the product. However, conventional adhesion strength testing is inherently limited in the face of package miniaturization, which brings about further technical challenges to quantify design integrity and reliability. Although there are many different interfaces in today's advanced electronic packages, they can be generalized into two main categories: 1) rigid to rigid connections with a thin flexible polymeric layer in between, or 2) a thin film membrane on a rigid structure. Knowing that every technique has its own advantages and disadvantages, multiple testing methods must be enhanced and developed to be able to accommodate all the interfaces encountered for emerging electronic packaging technologies. For evaluating the adhesion strength of high adhesion strength interfaces in thin multilayer structures a novel adhesion test configuration called “single cantilever adhesion test (SCAT)” is proposed and implemented for an epoxy molding compound (EMC) and photo solder resist (PSR) interface. The test method is then shown to be capable of comparing and selecting the stronger of two potential EMC/PSR material sets. Additionally, a theoretical approach for establishing the applicable testing domain for a four-point bending test method was presented. For evaluating polymeric films on rigid substrates, major testing challenges are encountered for reducing testing scatter and for factoring in the potentially degrading effect of environmental conditioning on the material properties of the film. An advanced blister test with predefined area test method was developed that considers an elasto-plastic analytical solution and implemented for a conformal coating used to prevent tin whisker growth. The advanced blister testing with predefined area test method was then extended by employing a numerical method for evaluating the adhesion strength when the polymer’s film properties are unknown.

TAKING THE PERSPECTIVE OF A SELLER AND A BUYER: IMPLICATIONS FOR PRICE ELICITATION AND PRICE FRAMING

This dissertation consists of two essays which investigate how assuming the role of a seller or a buyer affects valuations in a price elicitation task (essay I) and how different presentations of an equivalent price affect evaluations when a consumer plays the dual roles of a buyer and a seller in transactions involving trade-ins (essay II). Sellers’ willingness to accept (WTA) to give up a good is typically higher than buyers' willingness to pay (WTP) to obtain the good. Essay I proposes that valuation processes of sellers and buyers are guided by a motivational orientation of “getting the best.” For a seller (buyer) indicating WTA (WTP), getting the best implies receiving as much as possible to give up a specific good (giving up as little as possible to get the specific good). Results of six studies suggest that the WTA-WTP elicitation task activates different directional goals, leading to the WTA-WTP disparity. The different directional goals lead sellers and buyers to focus on different aspects and bias their cognitive reasoning and interpretation of information. By connecting the valuation process to the general motivation of getting the best, this research provides a unifying framework to explain the disparate interpretations of the WTA-WTP disparity. Many new purchases and replacement decisions involve consumers’ trading in their old products. In such transactions, the overall exchange may be priced either as separate transactions (partitioned) with price tags for the payment and the receipt or as a single net price (consolidated) which takes into account the value of the trade-in. Essay II examines whether consumers prefer a partitioned price versus a consolidated price presentation. The findings suggest that when consumers are trading in a product which has a low value relative to the price of a new product, they prefer a consolidated price. In contrast, when trading in a product which has high value, they prefer a partitioned price. The results suggest that consumers use the price of the new product as an anchor to evaluate the trade-in value, and the perception of the trade-in value influences the overall evaluation especially when the transaction is partitioned.