This chapter introduces the basics of semiconductor fabrication, including the basics of cleanroom, contamination control, yield, IC fab layout, testing, and packaging processes.

Objectives

After finishing this chapter, the reader will be able to:

• define yield

• explain the importance of yield

• describe the basic structure of a minienvironment cleanroom

• explain the importance of cleanroom protocols

• list four basic operations of IC processing

• name at least six processing areas of an IC fab

• list the commonly used facility systems in IC fabrications

• explain the purposes of chip packaging

• compare ceramic and plastic packaging

• describe standard wire bonding and flip-chip bump bonding processes

• list temperature requirements for packaging processes

• describe the purpose of an induced failure test.

2.1 Introduction

IC chip fabrication is a very complicated and time-consuming process. It begins with an IC design, formed with the help of powerful electronic design automation (EDA) software. The layouts of the design are then verified and taped out. In a mask shop, a photoresist (PR) layer is coated onto a chrome glass plate, and the designed pattern is printed by an electron beam writer or a laser writer. After PR development, a chromium etch process is used to transfer the PR pattern to the chrome glass to form the mask or reticle. After cleaning and inspection, the masks are ready to be shipped to IC fabs. A single IC chip requires 20 to 30 masks, depending on the type of device and the technology node.