Control and 3-dimensional simulation model of temperature variations in a rapid thermal processing machine
First Claim
1. A rapid thermal process for presetting and controlling a heating system used to heat a semiconductor wafer, the process comprising:
- a) initializing input data to a computer main program, the input data including indicia relating to the heating system and properties of the semiconductor wafer;
b) calculating an expected temperature for a plurality of three-dimensional wafer volume elements versus time, responsive to the input data indicia;
c) individually controlling a power level to multiple heating elements within the heating system, the power level being controlled, directly or indirectly, by the computer main program responsive to the expected temperature calculated for the volume elements to provide a predetermined temperature ramp rate and steady state level for minimal wafer temperature nonuniformity;
d) monitoring the wafer temperature with at least one temperature sensor; and
,e) providing a temperature feedback from the temperature sensor to, selectively, a heat controller or the computer main program, thereby providing for quick and accurate controlling of the wafer temperature.
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Abstract
Temperature nonuniformity across a semiconductor wafer during both the transient and steady state of a typical rapid thermal processing (RTP) cycle has been a deterrent in using RTP in many ULSI unit processes. The present invention consists of a three-dimensional mathematical model to study the temperature variation across a wafer in an RTP oven for given heating element power settings, during both the transient and steady state of a typical thermal cycle and control a heating element by a computer program. The validity of various models have been checked by performing a series of oxidation experiments.
68 Citations
16 Claims
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1. A rapid thermal process for presetting and controlling a heating system used to heat a semiconductor wafer, the process comprising:
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a) initializing input data to a computer main program, the input data including indicia relating to the heating system and properties of the semiconductor wafer; b) calculating an expected temperature for a plurality of three-dimensional wafer volume elements versus time, responsive to the input data indicia; c) individually controlling a power level to multiple heating elements within the heating system, the power level being controlled, directly or indirectly, by the computer main program responsive to the expected temperature calculated for the volume elements to provide a predetermined temperature ramp rate and steady state level for minimal wafer temperature nonuniformity; d) monitoring the wafer temperature with at least one temperature sensor; and
,e) providing a temperature feedback from the temperature sensor to, selectively, a heat controller or the computer main program, thereby providing for quick and accurate controlling of the wafer temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer control system for presetting and controlling a heating system to heat a semiconductor wafer, the system comprising:
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a) a main computer and computer program having input data, the input data including indicia relating to the heating system and properties of the semiconductor wafer; b) means for calculating an expected temperature for a plurality of three-dimensional wafer volume elements versus time, responsive to the input data indicia; c) a heat controller having an input signal from, selectively, a temperature indicator or the main computer; d) the heating system having a power input from the heat controller; e) at least one temperature sensor; and
,f) a temperature feedback means for feeding back temperature data from the at least one temperature sensor to, selectively, the heat controller or main computer, wherein the main computer outputs time, temperature, wafer X and Y coordinates for the volume elements, and heat intensity to preset and control the heating system power input. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification