USING OPTICAL EMISSION SPECTROSCOPY TO IMPROVE EQUIPMENT UPTIME FOR AN AL2O3 ALD PROCESS *

Transcription

1 USING OPTICAL EMISSION SPECTROSCOPY TO IMPROVE EQUIPMENT UPTIME FOR AN AL2O3 ALD PROCESS * JOHN LOO Samsung Austin Semiconductor Samsung Blvd. Austin, Texas * Presented at the AVS 5 th International Conference on Atomic Layer Deposition August 8-10, 2005, San Jose California

2 Installed OES unit with heater blankets

3 Typical Lightwind Emission Spectrum - ALD Process 5000 Wavelength Signal Intensity Wavelength03 Wavelength04 Wavelength01 Wavelength02 Wavelength Wavenength (nm) Typical emission spectra of an Al2O3 ALD process

4 Wafer01 Wafer02 Wafer03 Wafer04 Wavelength Intensity Wafer Processing Setpoint Window Typical monitoring of chamber affluent wavelength

5 SYSTEM INFORMATION Communication Link To Process Tool Process Chamber Optional Data System Optical Fiber Multi-channel Optical Emission Spectrometer Downstream ICP Plasma Emission Source (Sensor) Interface To Pump Lightwind Chemical Monitoring System RF Generator Interface Data Acquisition & Control Computer The Lightwind system monitors process chemistry via plasma-induced Optical Emission Spectroscopy (OES).

6 Wavelength Intensity Wavelength time trend of a long chamber coat. There is a distinct shape of the trend which indicates that the chamber is ready for post chamber maintenance release.

7 1st 5K Coat 1st 5K Coat 1st 5K Coat 1st 5K Coat 1st 5K Coat 1st 5K Coat 1st 5K Coat 2nd 5K Coat 2nd 5K Coat 2nd 5K Coat 2nd 5K Coat 2nd 5K Coat 2nd 5K Coat 2nd 5K Coat wavelength01 OH=309nm wavelength01 OH=309nm Wavelength time trend of two successive short coats ( ½ the time of the long coat ). This shows a repeatable seasoning curve in the same process chamber. Keeping this signature in mind a higher gas flow coat was attempted.

8 Improper trend indicating seasoning did not properly occur K Coats wavelength01 OH=309nm Proper trend indicating seasoning is complete wavelength01 OH=309nm 1st 5K 1st 5K 1st 5K 1st 5K 1st 5K 1st 5K 1st 5K 2nd 5K 2nd 5K 2nd 5K 2nd 5K 2nd 5K 2nd 5K 2nd 5K 49pt Contour Map performed after coating 49pt Contour Map performed after coating

9 DALD cc TMA Ar Bubbler Flow Coat 6min minutes wavelength01 OH=309nm Wavelength DALD02-5 5K Coat After the 6min 100c Coat These charts indicate that the same seasoning curve can be attained with a simple change to the coating recipe hours wavelength01 OH=309nm Wavelength

10 DALD02-5 5K Coat After the 6min 100c Coat Wavelength 1 wavelength01 OH=309nm hours of Chamber Coating DALD cc TMA Ar Bubbler Flow Coat 6min hours of Chamber Coating wavelength01 OH=309nm 6 min of Chamber Coating By understanding the response from the chamber affluent during chamber coating, qualification time ( time required to prepare a processing chamber for production material processing ) can be reduced from 6hours to 6min.

11 Chemical Supplier A Chemical Supplier B Wavelength Intensity Wavelength01 Wavelength02 Wavelength03 Wavelength04 In this example, precursor chemical suppliers were compared by overlapping full spectra. Critical wavelengths were previously indentified as shown above. Using OES provided additional information regarding the precursor chemical composition from both suppliers.

12 These charts show how OES monitoring of chamber affluent can detect changes to the reaction liquid fill level. As the bottle level drops, the wavelength intensity decreases. Bottle Fill = 100g Reference Line Bottle Fill Level = 63g Bottle Fill Level = 43g Bottle Fill Level 20g

13 Equipment A DALD Pre Wet Clean Wet Clean Release Trap install Trap Removed ALO_0039.bch PM5_Wavelength1.obs.avg ALO_0039.bch PM5_Wavelength8.obs.avg ALO_0040.bch PM5_Wavelength1.obs.avg 300 ALO_0040.bch PM5_Wavelength8.obs.avg 200 ALO_0042.bch PM5_Wavelength1.obs.avg 100 ALO_0042.bch PM5_Wavelength8.obs.avg 0 2 nd window install :00: :00: :00: :00: :00: :00:00 Here OES monitoring was used to evaluate a new pump trap design. Shortly after installation, the intensity of the monitored wavelength decreased leading to an early detection of a trap failure.

14 The use of OES provides critical information regarding processing system integrity before and after a schedule maintenance. Here is an example whereby OES data was utilized after a precursor bottle fill. This coupled with an in-situ precursor fill system drastically reduced the total time required. Bottle Removal PrePurge ( 4 hours ) Bottle Removal ( 1 hour ) New Bottle Post Purge ( 1 hour ) Qualification Thk/PCs (.5 hour ) Pre Fill Tool Setup ( 2 min ) Auto Fill Sequence Includes 2 purge sequences ( 20 min ) Qualification on 1 st two warmup wafers after PM release ( 8 min) By switching to an AutoRefill System and then confirming chamber integrity post the maintenance with OES data, total time reduced by 6 hours.