ION 104: Metrology and Process Control of Ion Implantation

This course begins with an overview of process control from the perspective of personnel working in the implant bay of a modern wafer fab. The wafer contour map is fully explained. Then three modern metrology techniques used to provide whole-wafer characterization of the implanted wafer are introduced: the four-point probe, the Therma-Probe, and a low dose optical monitoring system that uses a technique called optical densitometry. Since the four-point probe is the most widely-used implant metrology tool, an extensive review is made of the techniques required keep it in daily process-worthy condition. Contour maps from these three metrology tools are then used to provide the student with real-life examples of the performance of the ion implanter, annealer, and metrology equipment within the implant process. Then, the statistically correct method of constructing process control charts is introduced. Examples of control charts are shown to provide instructional techniques in evaluating examples of real-life process problems from the implant bays of different fabs. The course concludes with a review and a test that covers the salient points revealed in this presentation. Note: Students are encouraged to bring their own contour maps and process control charts to be analyzed by class members in two workshop sessions dedicated to the understanding of these thought processes.

• Review process control procedures in an implant bay
• Discuss implant metrology equipment and their respective output
• Review the methodology and techniques used in tracking implant data
• Participate in hands-on process problem-solving exercises in a workshop forum

This course is intended for process and maintenance technicians, equipment engineers, and new implant process engineers who wish to acquire the knowledge and procedures for implementing a process control program in the ion implant bay of a modern wafer fab.

Course Length: 1 day

Course Materials: Course notes and Ion Implant Applications Manual by C. B. Yarling (with W. K. Johnson), Ion Beam Press (1995)

Instructor: Chuck Yarling

1. Introduction

2. Process Control in Ion Implantation

3. Dynamics of the Wafer Contour Map

4. Metrology Tools in the Implant Bay

• Derivation of Sheet Resistance
• Four-Point Probe
• The Care and Feeding of Your Four-Point Probe
• ThermaProbe
• Optical Measurement System

5. Analyzing Wafer Contour Maps from Metrology Tools

6. Workshop: Process Troubleshooting with Contour Maps

7. Modern Methods of Tracking Implant Data

8. Analyzing Control Charts: Seeing Patterns In Data

9. Process Control Charts in the Implant Bay

10. Workshop: Process Troubleshooting with PC Charts

11. Advanced Process Control Techniques

• Gauge Capability Study
• Process Potential Index - Cp
• Process Capability Index - Cpk

12. Review

13. Test and Course Evaluation

14. References

15. Appendix