Duromer MID technology for system-in-package generation

The Duromer molded interconnect device (MID) technology for realization of a stackable system-in-package (SiP) is similar to conventional MID technology, which is usually realized using thermoplastic polymers, combining the functionality of housing and substrate into one device. Advantages of the conventional MID technology are the reduction of parts during assembly by integrating mechanical and electrical functionality into a device and the reduction of space, as MID allows a three-dimensional (3-D) integration of devices. A disadvantage of conventional technology, especially if combined with typical technical thermoplastics, is the large mismatch in coefficient of thermal expansion (CTE) between substrate and advanced microelectronic components as chip scale package (CSP) or flip-chip. This is reducing the applicability of thermoplastic MID to moderate temperature ranges and/or to rather robust components. To overcome this disadvantage, the use of low CTE duromer as epoxy molding compounds (EMCs) as base material for device assembly is proposed, generating a unique technology well adapted to SiP and microelectromechanical system (MEMS) packaging needs, the Duromer MID approach. The technological realization of Duromer MID uses conventional backend processes as IC bonding to flex, transfer molding using epoxy molding compounds, laser machining, metallization, and structurization processes well known from PCB processing. The use of existing equipment allows both a rather fast process implementation and a cost-effective manufacturing of the components. Within this paper, the investigations described previously are driven further toward a description of a generic packaging technology integrating detailed analysis of metallization processes and assembly issues. Summarized, this paper presents further process development and feasibility analysis of wafer-level packaging technologies for SiP solutions based on a Duromer MID approach.