Oxidation

 

Description: Formation of a stable silicon dioxide passivation layer and its use on a wafer. Methods, materials, equipment, tests, measurements, and processes of oxidation.

Length of time: 3 hrs.

Prerequisites:

Module: Crystal Growth and Wafer Preparation

Topics:

1. Uses for the silicon dioxide layer

Contamination control

Electrical insulation

Capacitor dielectric

MOS gates

2. Silicon dioxide layer growth

Processes

Chemistry

3. Oxidation process flow

4. Oxidation methods

Thermal

Wet

Dry

Anodic

5. Equipment and measurements for oxidation

6. Measurement of oxide layer thickness

7. Contamination targets and preclean

8. Safety aspects

 

Student objectives:

Student will be able to:

1. List major materials and equipment used in oxidation processes in semiconductor manufacturing.

2. Write a key chemical reaction used to produce silicon dioxide in semiconductor manufacturing oxidation processes.

3. Explain thermal dry and wet oxidation using sketches where appropriate.

4. Identify principle functions and sections of horizontal and vertical tube furnaces used in oxidation processes.

5. Use sketches to show the use of oxide layers as in MOS gates and solid state capacitors. Include a discussion of field oxides.

6. Compare and contrast dry and wet oxidation with respect to oxidation time, layer thickness and quality of each.

7. Explain anodic oxidation and its principle use in semiconductor manufacturing process.

8. Describe a wafer cleaning station and the need for contamination control before oxidation processes begin.

9. Discuss the major contamination targets in precleaning operations as well as the equipment and materials used.

10. List key factors that determine oxide thickness.

11. Explain technologies available to provide oxide layers less than 100 angstroms thick. Include a discussion of RTP and RTO systems.

12. Explain how to evaluate and measure layer thickness and dielectric properties.

13. Construct a process flow diagram highlighting oxidation steps from incoming wafer to evaluation.

14. Discuss precautions used to reduce explosion hazards in dry oxidation systems.