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70 SMT007 MAGAZINE I JANUARY 2023 When a project or customer deadline looms, outsourced semiconductor assembly and test (OSAT) providers may not have the resources to provide the parts needed in a timely man- ner. OSATs aren't structured to support prod- uct development and device verification pro- cesses. Smaller, more nimble companies can have open-cavity plastic packages readily avail- able for quick-turn assembly of prototypes and small quantities of packaged devices. is challenge becomes even more pro- nounced when the devices in question are developed for military or aerospace end prod- ucts, which have stringent requirements with respect to long-term robustness and func- tionality. In the U.S., security restrictions also require that assembly be provided by a stateside supplier, but most OSATs are located offshore. What Is OCPP? Reliability data show that OCPPs have long- term value in both their ability to withstand challenging natural environments and to guard against obsolescence. When a military, avion- ics, or aerospace end product needs devices for which packages may no longer be available from a previous provider, redesigning is rarely an option. e manufacturer needs packages that can be quickly developed to accommodate existing functionality and fit existing package footprints. OCPPs are a type of quad flat pack (QFP) leaded package that can withstand hundreds to thousands of thermal cycles, at temperatures between -40°C and 125°C. e OCPP concept is time-tested and proven as a means of com- bating package obsolescence. Military ves- sels such as long-serving battleships, for one example, have benefited from the use of OCPP packages to preserve existing device designs and footprints, keeping the ship from having to be dry-docked. is long-life implementation of electronic components is a well-established pattern for military and aerospace applications. In ser- vice for decades, they require devices with the quality and robustness to remain operational over the end product's lifetime. OCPP-type packages have proven their resilience for this market. A wide variety of options can be imple- mented using open-cavity plastic packages. Once the molding compound is removed and the precious metal surfaces cleaned, exposing the die attach page and bond fingers, a variety of encapsulation approaches can be utilized. Figure 1 illustrates some of these options. OCPP is analogous to a high-quality pre- owned car. Using OCPP allows reclaiming of existing "dummy" packages, e.g., electri- cal rejects, test packages, or excess inventory. Aer removing plastic and existing die down to the copper, a new package is then built within the OCPP shell. OCPP is well suited for cost-sensitive projects or those that only require small batches. A n o t h e r k e y a p p l i - cation for OCPP is to employ it as an interim solution, optimizing the package and working out any kinks, before transi- tioning to open-molded plastic packages, which enable rapid turnarounds Figure 1: Encapsulation options for OCPP.