Thermal processing system with cross flow injection system with rotatable injectors

Abstract

An apparatus is provided for thermally processing substrates held in a carrier. The apparatus includes an injection system which provides for selectable injection of gases to the process chamber. The injection system comprises one or more elongated injection tubes having a plurality of injection ports or orifices distributed in the tubes for directing flow of reactant and other gases across the surface of each substrate. The elongated injection tubes are rotatable about an axis in 360 degrees.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 60 / 506,354 filed Sep. 25, 2003, the disclosure of which is hereby incorporated by reference in its entirety, and is related to PCT application Serial No. PCT / US03 / 21575 entitled Thermal Processing System and Configurable Vertical Chamber, which claims priority to U.S. Provisional patent application Ser. Nos. 60 / 396,536 and 60 / 428,526, the disclosures of all of which are hereby incorporated by reference in their entirety.TECHNICAL FIELD [0002] The present invention relates generally to systems and methods for heat-treating objects, such as substrates. More specifically, the present invention relates to an apparatus and method for heat treating, annealing, and depositing layers of material on or removing layers of material from a semiconductor wafer or substrate. BACKGROUND [0003] Thermal processing apparatuses are commonly used in the manufactur...

AI Technical Summary

Benefits of technology

"The present invention provides an apparatus and method for isothermally heating work pieces, such as semiconductor substrates, for various processes such as annealing, diffusion, deposition, etching, and removal. The apparatus includes a process chamber with a movable pedestal and a removable thermal shield to isolate the process chamber. The bottom wall of the process chamber has a movable pedestal with heating elements, and a shutter to isolate the process chamber when the pedestal is in a lowered position. The apparatus also includes a magnetically coupled repositioning system to reposition the carrier during thermal processing. The apparatus further includes a liner and a cross-flow injection system to direct flow of fluids across the substrates. The invention also includes an injection system for selectable injection of gases to the process chamber. The technical effects of the invention include improved process control, faster processing times, and reduced damage to substrates."

Problems solved by technology

This arrangement is undesirable since it entails a larger chamber volume that must be pumped down, filled with process gas or vapor, and backfilled or purged, resulting in increased processing time.

Moreover, this configuration takes up a tremendous amount of space and power due to a poor view factor of the wafers from the heaters.

Other problems with conventional thermal processing apparatuses include the considerable time required both before processing to ramp up the temperature of the process chamber and the wafer to be treated, and the time required after processing to ramp down the temperature.

Furthermore, additional time is often required to ensure the temperature of the process chamber has stabilized uniformly at the desired temperature before processing can begin.

Thus, the time required to quickly ramp up and / or down the temperature of the process chamber to a uniform temperature significantly limits the throughput of the conventional thermal processing apparatus.

However, this approach also increases the magnitude of the risk should something go wrong during processing.

That is a larger number of wafers could be destroyed or damaged by a single failure, for example, if there was an equipment or process failure during a single processing cycle.

Another problem with this solution is that increasing the size of the process chamber to accommodate a larger number of wafers increases the thermal mass effects of the process chamber, thereby reducing the rate at which the wafer can be heated or cooled.

Moreover, larger process chambers processing larger batches of wafers leads to or compounds a first-in-last-out syndrome in which the first wafers loaded into the chamber are also the last wafers removed, resulting in these wafers being exposed to elevated temperatures for longer periods and reducing uniformity across the batch of wafers.

Another problem with the above approach is that systems and apparatuses used for many of the processes before and after thermal processing are not amenable to simultaneous processing of large numbers of wafers.

Thus, thermal processing of large batches or large numbers wafers, while increasing the throughput of the thermal processing apparatus, can do little to improve the overall throughput of the semiconductor fabrication facility and may actually reduce it by requiring wafers to accumulate ahead of the thermal processing apparatus or causing wafers to bottleneck at other systems and apparatuses downstream therefrom.

Unfortunately, conventional RTP systems have significant shortcomings including the placement of the lamps, which in the past were arranged in zones or banks each consisting of a number of lamps adjacent to sidewalls of the process chamber.

This configuration is problematic because it takes up a tremendous amount of space and power in order to be effective due to their poor view factor, all of which are at a premium in the latest generation of semiconductor processing equipment.

Another problem with conventional RTP systems is their inability to provide uniform temperature distribution across multiple wafers within a single batch of wafers and even across a single wafer.

There are several reasons for this non-uniform temperature distribution including (i) a poor view factor of one or more of the wafers by one or more of the lamps, and (ii) variation in output power from the lamps.

Moreover, failure or variation in the output of a single lamp can adversely affect the temperature distribution across the wafer.

However, the moving parts required to rotate the wafer, particularly the rotating feedthrough into the process chamber, adds to the cost and complexity of the system, and reduces the overall reliability thereof.

Yet another troublesome area for RTP systems is in maintaining uniform temperature distribution across the outer edges and the center of the wafer.

Most conventional RTP systems have no adequate means to adjust for this type of temperature non-uniformity.

As a result, transient temperature fluctuations occur across the surface of the wafer that can cause the formation of slip dislocations in the wafer at high temperatures, unless a black body susceptor is used that is larger in diameter than the wafer.

For example, there are no adequate means for providing uniform power distribution and temperature uniformity during transient periods, such as when the lamps are powered on and off, unless phase angle control is used which produces electrical noise.

Repeatability of performance is also usually a drawback of lamp-based systems, since each lamp tends to perform differently as it ages.

Replacing lamps can also be costly and time consuming, especially when one considers that a given lamp system may have upwards of 180 lamps.

The power requirement may also be costly, since the lamps may have a peak power consumption of about 250 kWatts.

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