TABLE OF CONTENTS Patterning is the series of processes that establishes the shapes, dimensions, and placement of the required physical parts (components) of the IC in and on the wafer surface layers. This chapter presents the first four steps of a basic ten-step photo process and a discussion of photoresist chemistry.
Upon completion of this chapter, you should be able to:
Sketch wafer cross sections showing the basic ten-step photomasking process.
Explain the reaction of negative and positive photoresists to light.
Describe the correct resist and mask polarities required to produce holes and islands in wafer surface layers.
Make a list of the major process options for each of the ten basic steps.
Select from the list in objective 4 the processes used to pattern features in micron and submicron sizes.
Describe the need for, and process steps used in, double masking, multilayer resist processing, and planarization techniques.
Explain the use of antireflective coatings and contrast enhancement in the patterning of small feature sizes.
List the optical and nonoptical methods used for alignment and exposure.
Compare the equipment and advantages of each alignment and exposure method.
Patterning is one of the basic operations. At the end of the operation, a surface layer is left with either a hole or an island. (See Fig. 8.1.) Patterning is also called photolithography, photomasking, masking, oxide removal (OR) ), metal removal (MR), and microlithography.
Patterning is...
