1. Spin-on Glass and Particle Incorporation Thomas Stratton Purdue MSREU 2002 Advisor: Dr. Kvam

2. Introduction Microcapacitors are vital to the operation of today’s computers, radios and other microelectronics In this project we hope to study the effects of ceramic particle incorporation within a low-k material

3. MSSQ Methylsilsequioxane (MSSQ) is a silicon-based organic polymer Has strong resistance to cracking Low dielectric constant Manufacturer quote 2.6 @ 1MHz Experimental result 1.85 @ 10kHz Good planarizing qualities Forms a flat, even, consistent layer Manufacturer 4000 Angstroms Experimental 8000 Angstroms

4. MSSQ General Structure

5. Objectives Spin an even, flat, defect-free layer of MSSQ Test the dielectric properties of capacitors formed by MSSQ between two platinum electrodes Suspend ceramic particles with the MSSQ Spin the suspension on slides Test the dielectric properties of the MSSQ- ceramic suspension

6. Procedure Sputter a layer of platinum on glass laboratory slides Ready the MSSQ (or suspension) Spin on layer of MSSQ (or suspension) Bake on hot plate (varying temperatures) Cure in oven at 425 degrees C Sputter a top contact point Test properties

7. Reducing Defects Due to non-ideal conditions, many surface defects appeared during initial spinning Original attempts to reduce spin defects were focused on improving cleanliness and reducing processing impurities After improving cleanliness failed to reduce defects, reducing the total spinning time to below manufacturer’s suggestion was conceived and implemented with immediate results

8. Pictures of MSSQ slides

9. Table of Results Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7 Initial 3100 rpm7s9s 6s7s 1500 rpm10s8s11s 4s8s0s “Dry” 3100 rpm0s9s 8s0s MSQ drops used6121516798 Cleanliness (comparative) Fair GoodVery Good Very Good Very Good Very Good Errors per cm 2 33.550.2141.078.8145.030.4720

10. Chart of Results

11. Barium Titanate Powder High Dielectric Constant (k=233) Readily available due to other students in the lab using BaTiO 3 in REU projects Particles ranged between 70 nm and 1900 nm, high purity

12. Suspending Suspended 2.9496 grams of Barium Titanate powder in 1.55 grams of MSSQ Made white liquid that hardened very quickly and tended to clump after dispersal Suspension was then applied to glass slides

13. Difficulties with the Suspension Suspension did not spread evenly, surface was “boulder-strewn terrain” Suspension tended to harden very quickly Contact pads did not sputter on the cured suspension very well Capacitor leakage and error was a significant problem

14. Boulder-strewn terrain

15. Results Found minimum k-values of 4.51 and 4.01 (both at 10kHz) These minimum values are greater than the MSSQ’s k-value at 10 kHz of 1.85, which shows that the Barium Titanate powder must be having some effect

16. Future Work Changing the percentages of BaTiO 3 and MSSQ in the suspension Studying effects of other ceramic suspensions Studying how particle size, orientation, and composition affect dielectric properties Finding a suitable dispersant to achieve a more balanced distribution of ceramic