Structural devices
Structural devices

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Structural devices

8 Etching

8.1 Introduction

Etching is central to all forms of micro-device production, from microelectronics and memory through to microsystems technology. Although materials, geometries and feature sizes vary widely, etch processes have a few common features and requirements:

  • Etching acts by converting solid material into a gas or a liquid that can be pumped or flushed away.

  • It is usually restricted to the openings in a lithographically defined mask, and since this mask must survive for the duration of the process the etch must be selective.

  • The cross-sectional shape (profile) of the etched hole is usually important; the most common requirement, both for microelectronics and MEMS, is for near-vertical walls without undercutting of the mask.

  • The roughness of the etched surface and any electrical or mechanical damage to the device must be controlled.

  • A consistent result is needed both across a wafer (uniformity) and between wafers (repeatability), since this determines the proportion of working devices (the yield); it may be necessary to monitor the etch to detect when the process is finished (endpoint).

  • Etch rate is always important, since time is money.

T356_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has over 40 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus