Method of treating a substrate

Abstract

A method of cleaning a substrate within a controlled environment includes placing the substrate into a high pressure vessel. The high pressure vessel is then supplied with a dense fluid under pressure. The dense fluid is contacted with the substrate for a selected period of time to at least partially remove a contaminant contained on the substrate. After the selected period of time, the vessel is depressurized to at least partially convert the dense fluid into a vapor. The vapor is then subjected to an energy field to form a plasma within the vessel which is used to treat the substrate for a second selected period of time. The thus cleaned substrate is then removed from the vessel.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) [0001] This application is a divisional application of U.S. patent application Ser. No. 10 / 428,793 entitled METHOD AND APPARATUS FOR SELECTIVE TREATMENT OF A PRECISION SUBSTRATE SURFACE, filed on 2 May 2003, which claimed the benefit of similarly named U.S. Provisional Application No. 60 / 377,197 filed on 3 May 2002, each of which are hereby incorporated herein by reference.BACKGROUND OF INVENTION [0002] As technology has advanced, the system performance requirements and complexity of manufactured and assembled precision instruments and devices have increased, while the size of individual components and assemblies have decreased. This continuing miniaturization process has magnified the susceptibility of precision substrates and surfaces to contamination. Specific effects of contamination depend on the type of substrate, materials used, and system in which the device is used. [0003] Thus, an important element of any precision manufacturing or...

AI Technical Summary

Benefits of technology

[0045] Thus, the alternative combination of dry surface cleaning and modification technologies discussed above and used in the present invention are very attractive but have limitations due to varying levels of cleaning performance, line-of-sight effectiveness, and potential damage (i.e., plasma etching) to substrate surfaces if contacted for an extended treatment period or if used at excessive energy levels. However, if used in certain combinations, an instant cleaning method may be established for removing a variety of contaminants from precision substrate surfaces based on the nature of and interaction between contamination and surfaces. The nature of the various contaminants and substrates; the contaminant-substrate and contaminant-contaminant adhesion forces present must be fully understood. Furthermore, the various interactions between the cleaning method and the substrate and substrate features present thereon must be understood. Once all of these interrelationships and discrete cleaning parameters are understood, an instant and enabling relationship may be established which selectively removes a contaminant or group of contaminants from a substrate, in pre-determined and discrete steps, without damaging the various substrate features which may be present, for example patterned resists, microvias, microstructures, and beneficial coatings. Moreover, the present invention uniquely and easily lends itself to being performed in a single process chamber or integration within a staged or in-line cluster tool. This is beneficial since it reduces re-contamination of precision substrate surfaces during handling.

[0046] An aspect of the present invention is to ascertain and apply an instant and enabling dry surface treatment combination which eliminates wet processing and rinsing and drying steps, increases cleaning and modification tool productivity, decreases equipment cost, and size, reduces pollution, and improves substrate cleanliness, quality and yield.

[0047] The present invention illustrates a method in which an instant enabling, dry, and selective cleaning combination is established using four dry techniques described above; plasma, dense fluids, electrohydrodynamic cleaning and UV / Ozone cleaning. Using two or more of these techniques sequentially or simultaneously as an instant combination, virtually any type of contamination may be effectively and selectively removed from a substrate without damaging the precision substrate surface.

Problems solved by technology

Although very attractive, these individual techniques have discrete characteristics, that is application and performance limitations, which prevent them individually from properly treating a substrate surface and may even damage a surface.

For example, physical damage to a substrate surface may be caused by a particular technique due to excessive cleaning energies required (i.e., high spray pressure, high plasma energy level, presence of oxidizing chemistries) and excessive treatment periods required to achieve a certain surface cleanliness level.

Most conventional wet and dry combinations create significant waste by-products, pose worker exposure dangers, and consume tremendous amounts of water resources.

However, complete drying of precision substrates following cleaning by wet methods is limited due to hydration of small capillaries, vias and interstices that may be present.

Moreover, a lack of substrate surface selectivity can be limiting in many applications, because the entire precision device is subjected to the combinational cleaning method that complicates cleaning, drying and compatibility issues.

This superheated or saturated drying vapor often requires the use of large quantities of a hot volatile organic material.

A limitation with this type of drying technique is its use of the large solvent quantity, which is hot, highly flammable, and extremely hazardous to health and the environment.

Another limitation with such a drying technique is its cost, which is often quite expensive.

The aforementioned conventional technique fails to provide such desired features, thereby reducing the yield of good precision devices.

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