Cynthia S. Milkovich

Double sided flexible carrier with discretes and thermally enhanced FCA/COF

This paper describes an electronic assembly that uses SMT components, wire bonded chips as well as area array chips attached to a flexible carrier. The wire bond chip is reworkable until encapsulation. Heat spreaders are attached to flip chips and wire bond chips with thermally conductive adhesives. Volume constraints imposed by a system design can he satisfied by populating both sides of a flexible carrier with components. Potential cost savings and reliability gains are possible with this electronic assembly design. A single flexible carrier with chips can replace multiple printed circuit cards and two levels of interconnection.<<ETX>>

Improvement in reliability with CCGA column density increase to 1 mm pitch

Discusses reliability testing of a 1 mm pitch ceramic column grid array (CCGA) test vehicle assembly including accelerated thermal cycling, insulation resistance testing, and mechanical stress tests such as shock and vibration. The experimental matrix includes several variables such as PCB thickness. The attributes of the package and card test vehicles, along with critical assembly parameters will be discussed with a focus on the resulting reliability data. Also included in the paper will be a comparison of the 1 mm pitch CCGA assembly reliability to 1.27 mm control CCGA locations on the same test cards and to previous 1.27 mm pitch CCGA test results. The paper will discuss the test methods and results from this experiments matrix.

Assembly of Area Array Components

Surface mount technology (SMT) has become the accepted standard for electronic assembly throughout the world. Surface mount packaging dominates the packaging industry due to the space saving and increased wiring capability achieved by directly mounting components on the surface of a board as opposed to the need for through holes in a printed circuit board (PCB). Cost, performance and ease of assembly have been the drivers in the trend away from DIP (dual-in-line package) packages and PTH (plated through hole) assembly to SMT. SMT packages include a variety of leaded and ball grid array packages all of which are mounted to conductors on the surface of a circuit card (Fig. 19-1). SMT assembly has increased dramatically over the past ten years typically allowing 1000-10,000 soldered connections per board as opposed to 250-4000 connections for similar through-hole assemblies. This chapter describes SMT assembly materials, equipment and process techniques in assembly of area-array or Ball Grid Array (BGA) packages including ball grid arrays (BGAs) and chip scale packages (CSPs).