Integrated Circuits packaging

With sustained growth averaging over 8% a year since 1985, electronics are now an integral part of our daily and professional lives. In 2022, sales of electronic components alone accounted for nearly $600 billion, 80% of which was for integrated circuits alone, and the trillion-dollar mark is predicted for 2030.

This sustained growth in microelectronics has always been driven by the emergence of new applications: infrastructure electronics in the 1980s, PCs at the turn of the 1990s, the Internet at the end of the 20th century, then more recently nomadic applications (notably smartphones) and finally the Internet of Things (IoT). Packaging has supported this growth thanks to three major technological breakthroughs:

• the widespread use of surface-mount boxes (SMDs) from the mid-1980s;

• the introduction of housings on organic substrates from the mid-1990s, which significantly increased the number of contacts (contacts only peripheral to contact matrices);

• the widespread use, from the mid-2000s onwards, of dedicated boxes for each application.

The primary function of packaging is to make integrated circuits easy to handle, and thus to establish electrical interconnections with the customer circuit (printed circuit board) thanks to standardized formats (identical for all manufacturers). Of course, packaging also dissipates the heat generated during operation and protects the microelectronic chip from the environment, thus contributing to the component's reliability. For emerging package types, this boundary between chip and package is becoming increasingly blurred.

First, we describe in detail the main unit assembly steps and the four main types of associated interconnect substrates (metal, ceramic, organic and new 3D substrates). This then enables us to describe the main types of package, including those dedicated primarily to wearable applications and the Internet of Things.

Next, the role of packaging in terms of thermal and electrical performance is highlighted. Although the main manufacturers carry out environmental tests, from the qualification of a new component to the commercial phase, the conditions of customer use determine the overall reliability of the function. With the emergence of highly compact packages, second-level reliability, i.e. that corresponding to the package mounted on a printed circuit board, is a point to be taken into account right from the circuit design stage.

A glossary and a table of acronyms and symbols are provided at the end of the article.