Spin Coating is basically a procedure which is used to deposit uniform thin films to any flat surface of work piece. Usually a small amount of coating material is applied on the centre of the work piece’s surface when the disk is spinning at very low speed. Here in this process we are using the basic principle of centrifugal force. This is applied due to the spinning of Disk.

1. SPIN
COATING
Design and Fabrication of low cost Spin
Coater

2. Mr. Sumit Shoor
UID: 14602
Asst. Professor
School of Mechanical
Engg.
 Saurabh Pandey
 Kapil Raghuwanshi
 Sudhir Yadav
 Punit Kumar
Research Supervisor Group Members

3. Agenda
 Introduction to spin coating
1) Definition and brief history of spin coating
2) Uses of spin coating technology
 Physics of spin coating
1) Basic physics behind spin coating
2) Key stages of spin coating process
 Materials and modeling
1) Specification of materials/equipments
2) Common spin coating defects
3) Cost analysis

4. Agenda
 Result and discussion
1) Graphs
2) Spin coating troubleshooting process
 Conclusion and future scope
1) Advantages and disadvantages
2) Future scope

5. What is spin coating??
 A process in which solution is spread evenly
over a surface.
 Spin coating will result in a relatively uniform
thin film of a specific thickness.
 Spin coating is an important way of creating
thin films in the microelectronics industry.

6. History of Spin Coating
 In 1958 Emsile et. Al. Developed the first spin
coating model.
 Then again in 1978 mayerhofer et. Al.
developed with several simplifications.

7. Physics of spin coating
 Centrifugal force is responsible for the spread
of liquid over the substrate.
Centrifugal force:
It is a apparent force that draws a rotating
body away from the centre of rotation cause by
inertial of the body.

8. Key stages of spin coating process
 This process basically consist of four steps:
1. Loading of substrate
2. Dispense of coating fluid
3. Film casting
4. Drying

9. Material and Modeling
 Tin for outer cabinet
 Pewter for clamps
 Plastic pot for outer covering
 Plywood for Disk
 Plastic syringe for deposition feed
 A. C. motor (9500 RPM)
 Regulator (250 watt)
 Wires, Plugs, Glass sample, etc.

10. Common defects in spin coating
 Bubbles
 Swirling Pattern
 Chuck mark
 Uncoated area substrate
 Pin Hole defect

11. Cost analysis

12. Result & Discussion
 Graph between film thickness Vs. Spin time
 Graph between film thickness Vs. spin speed

13. Spin coating trouble shooting process

14. Spin coating trouble shooting process
 Air bubbles on wafer surface
Air bubbles in dispensed fluid (resin)
Dispense tip is cut unevenly or has burrs or defects
 Comets, streaks, or flares
Fluid velocity (dispense rate) is too high
Spin bowl exhaust rate is too high
Resist sits on wafer too long prior to spin
Spin speed and acceleration setting is too high
Particles exist on substrate surface prior to dispense
Fluid is not being dispensed at the center of the substrate surface
 Swirl pattern
Spin bowl exhaust rate is too high
Fluid is striking substrate surface off center
Spin speed and acceleration setting is too high
Spin time too short

15. Conclusion & Future scope
 A cost effective spin-coater was successfully
designed and fabricated.
 Spin coaters are ideal tools for the preparation
of thin films.
 We can use different type of solution.
 Relationship between film thickness Vs. speed
and time.

16. Advantages
 Absences of coupled process variables.
 Ease in changing film thickness.
 Low cost and fast operating system.
 Uniform film thickness over the surface.
 Easy to operate.
 Less time consuming.

17. Disadvantages
The disadvantage of spin coating are few, but
they are becoming more important as
substrate size increases and photo resist cost
rise.
 Large substrate size.
 Lack of material efficiency.
 Coating material wastage.

18. Future scope
 By including micro processor in the main
circuit we can include auto on/off system.
 We can also add a digital display.

19. Thanks

20. Questions ??