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Rochester I nstitute of T echnology 

M icroelectronic Engineeri ng 

ROCHESTER INSTI TUTE OF TECHNOLOGY 

M ICROELECTRONIC ENGINEERING 

 Rapid Thermal Processing (RTP)

 

Dr. Lynn Fuller Webpage: http://people.rit.edu/lffeee Microelectronic Engineering

  Rochester Institute of Technology  82 Lomb Memorial Drive  Rochester, NY 14623-5604  Tel (585) 475-2035

 

Fax (585) 475-5041  Email: Lynn.Fuller@rit.edu

  Department Webpage: http://www.microe.rit.edu

3-27-2010 lec_RTP.ppt

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OUTLINE 

IntroductionEquipmentProcesses for:

Activation of Ion Implanted ImpuritiesRapid Thermal Processing of DielectricsSilicidation and Contact Formation

Thermoplastic StressReferences

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INTRODUCTION 

Rapid Thermal Processing (RTP) can be used to reduce thethermal redistribution of impurities at high temperature. Forsmall devices this is an important consideration and as a resultmost engineers make use of low temperature processes. Some

ion implants require high temperature (at least 1000 °C) thusRTP is a promising technology.

RTP was originally developed for ion implant anneal but has broadened its application to oxide growth, chemical vapordeposition, and silicidation.

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RAPID THERMAL PROCESSING (RTP) 

Gas In

Heat Lamps

Computer Control Process

Chamber 

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RAPID TEMPERATURE RISE 

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RTP SYSTEM 

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THIN GATE OXIDE GROWTH BY RAPID THERMALPROCESSING (RTP) 

Textbooks say that 150Å of oxide can be grown by RTP at 1100°C in 60 sec.

From Textbook by S. Wolf  AG 610 at RIT

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RTP TH IN OXIDE GROWTH 

Poly

1.8 nm

Oxide

Silicon

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RTP RECIPE 

300Delay

55005500-60-250201000480SS

55005500-60-25020100010SS

1000120Ramp

10Delay

IcoldIwarmDgainGainT swTemp(C)

Time(sec)Step

Sébastien Michel, February 2005Steve Parshall, Kazuya Tokunaga, May 2005

Recipe for RTP Oxide, time during SS (Steady State) was changedto obtain different oxide thicknesses, 60s, 120s, 240s, and 480s

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OXIDE TH ICKNESS MEASUREMENTS 

 A71.245132.36174.22271.26Center Pt

%14.23428.92920.18737.112STDDEV A53.86657.249130.35167.06Min

 A71.245132.36174.22271.26Max

 A67.04104.29150.13211.53Mean

Min.1248Time

The data shown was obtained usingthe 5 point 6”wafer Spectromap RTP Oxide at 1000 C, Dry O2

1.421.451.451.45n

 A55.77143.03167.59272.54Xox

Min1248Time

The data shown was obtained using the VASE (Variable Angle

Spectroscopic Ellipsometer)

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RTP OXIDE QUALI TY MEASUREMENTS 

1511267883Ts

7.05E+115.94E+115.53E+114.66E+11Qfb

4.13E+114.32E+113.05E+112.76E+11Dit

4.73E+114.28E+114.26E+113.55E+11Qox

7.56E+141.46E+141.64E+141.13E+14 NSC

1 minute2 minutes4 minutes8 minutesTime

Measurements made using the SCA (Surface Charge Analyzer)

Dit is close to Bruce Furnace thermal gate oxide valuesTypically ~1E11

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ULTRA SHALLOW JUNCTION FORMATION 

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SIL ICIDE AND BARRIER LAYER FORMATION 

Silicide formation includes Ti, Pt, W, Ta, Mo, and Co. TiSi2 isformed at 900 C in pure N2. Titanium is sensitive to H2O and O2in the ppm levels.

TiN barrier layers can be formed by reacting Ti with N2 or NH3

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I LLUMINATION UNIFORM ITY AND WAFERTEMPERATURE UNIFORM ITY 

Uniformity of temperature across the wafer is the most important parameter. Local across the wafer temperature gradients cause stress.

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LAMP-BASED RTP 

Lamp based RTPsystems have been thechoice for the pastseveral years. Special

 physical configurations

have used to provideadditional heat towardsthe outer edge of a roundwafer. These systemsare cold wall systems so

more power is needed atthe wafer edge than inthe center of the wafer.

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SUSCEPTOR BASED RTP SYSTEM 

In the susceptor-based, hot-wallsystem, heating is achieved by

 placing wafers in close proximityto a heated thermal mass andthereby heating the wafers with a

uniform flux of relatively longwavelength radiation. In such asystem, the initial temperatureramp-up rate increases withincrease in process temperature.Heat-up and cool-down rates in

excess of 100 °C/sec.

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TITANIUM SIL ICIDE FORMATION RECIPES 

FACTISI1.RCP (step 1 – form TiSi)Delay 30 sec.Ramp 75 °C/sec. To 650°CSteady State 60 sec.at 650°CRamp 125°C/sec. To 300°C

FACTISI2.RCP (step 3 – form TiSi2)Delay 30 sec.Ramp 75 °C/sec. To 800°CSteady State 60 sec. At 800°CRamp 125°C/sec. To 300°C

Etching of Ti Metal (step 2)

Heat the Sulfuric Acid:HydrogenPeroxide (1:2) mixture on ahotplate to 100°C (set platetemperature to 150°C)

Etch for 1 min 30 sec. Thisshould remove the Ti that is ontop of the silicon dioxide but not

remove TiSi that was formed onthe polysilicon and D/S regions.It also removes unreacted Timetal over the TiSi on the polyand D/S regions.

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SUMMARY 

Rapid thermal processing was developed to enable short timehigh temperature implant annealing. Generally, the wafer restson quartz pins in a flow tube and is heated using a bank of highintensity filament lamps.

Problems with RTP include temperature measurement andthermal uniformity of the wafer. Excessive temperaturegradients across the wafer cause thermoplastic stress that maylead to wafer warpage and/or slip. Rapid thermal processing

has been extended to include silicide and barrier metalformation, thermal oxidation, chemical vapor deposition, andepitaxial growth.

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REFERENCES 

1. “The Science and Engineering of Microelectronic Fabrication”,Stephen A. Campbell, Oxford University Press, 1996.

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HOMEWORK - RTP 

1. Describe the application of RTP for ion implant anneal.2. Discuss why RTP would be good for gate oxide growth.