Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
2001-05-24
2004-11-02
Markoff, Alexander (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S019000
Reexamination Certificate
active
06810886
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of semiconductor manufacturing. More specifically, the present invention relates to an improved chamber cleaning method via a rapid thermal process during the cleaning period.
2. Description of the Related Art
An important way to improve quality and overall efficiency in fabricating devices is to clean the chamber effectively and economically. During processing, reactive gases released inside the process chamber form layers such as silicon oxides or nitrides on the surface of a substrate being processed. Undesirable deposition occurs elsewhere in the process apparatus, such as in the area between the gas mixing box and gas distribution manifold. Undesired residues also may be deposited in or around the exhaust channel, the liners and walls of the process chamber during such processes. Over time, failure to clean the residue from the process apparatus often results in degraded, unreliable processes and defective substrates. Without frequent cleaning procedures, impurities from the residue built-up in the process apparatus can migrate onto the substrate. The problem of impurities causing damage to the devices on the substrate is of particular concern with today's increasingly small device dimensions. Thus, process system maintenance is important for the smooth operation of substrate processing, as well as resulting in improved device yield and better product performance.
Frequently, periodic chamber cleaning between processing of every N substrates is desired to improve process system performance in producing high quality devices. Providing an efficient, non-damaging clean of the chamber and/or substrate often is able to enhance performance and quality of the devices produced. Two methods of cleaning a process chamber in the art are in-situ cleaning (also known as dry-etch cleaning) and wet cleaning.
In an in-situ cleaning operation, process gases are evacuated from the process chamber and one or more cleaning gases are introduced. Energy is then applied to promote a reaction between the gases and any residues which may have accumulated on the process chamber's interior surfaces. Those residues react with the cleaning gases, forming gaseous by-products which are then exhausted from the process chamber, along with non-reacted portions of the cleaning gases. The cleaning process is followed by the resumption of normal wafer processing.
In contrast to an in-situ cleaning procedure, in which the process chamber remains sealed, a wet cleaning procedure is performed by breaking the process chamber's vacuum seal and manually wiping down the chamber's interior surfaces. A wet cleaning procedure is normally performed to remove residues which are not entirely removed by the in-situ cleaning process, and thus slowly accumulate over time. A solvent is sometimes used to dissolve these residues. Once cleaned, the process chamber is sealed and normal processing is resumed.
Unfortunately, such cleaning operations affect a substrate processing system's throughput in a variety of ways. For example, system throughput is reduced by the time involved in performing cleaning operations. In an in-situ cleaning process, time is spent evacuating process gases from, and introducing/evacuating the cleaning gases into/from the process chamber. Flow rates, plasma power levels, temperature, pressure, and other cleaning process conditions must also be reset to desired levels after the cleaning process is completed. When a wet clean is performed, opening the process chamber and physically wiping the chamber's interior surfaces results in even more downtime because the process must subsequently be re-stabilized. It is thus desirable to reduce the frequency with which such cleaning operations are performed.
Additionally, frequent cleaning operations tend to increase wear on the process chamber components. For example, in-situ cleaning is typically performed using fluoridated carbons (e.g., CF.sub.4, C.sub.2 or F.sub.6) or similar fluorine-containing gases (e.g., NF.sub.3) due to their highly reactive nature. Unfortunately, exposure to plasmas created from such gases often causes the deterioration of process chamber components. This increased wear can lead to component failure; thereby causing extended downtime, and adversely affecting processing system throughput.
The use of reactive gases in cleaning process chambers, however, also suffers from a further disadvantage. The same radicals that provide desirable cleaning characteristics may themselves cause the formation of residues. For example, the use of such gases can cause the accumulation of polymer residues, which also exhibit undesirable qualities. The addition of oxygen to the cleaning process gas may reduce the formation of such polymer residues. In particular, ozone or an oxygen/ozone mixture may provide the desired reduction in polymer formation while speeding the cleaning process, due to ozone's greater reactivity.
Another example of residues generated by cleaning gases is the cleaning residues often formed by the use of fluoridated compounds in certain cleaning processes. These compounds may react with the aluminum or anodized aluminum which makes up many of the standard process chamber's components to form an aluminum fluoride residue on the interior surfaces of the chamber and the chamber's components. The reaction between the aluminum and the fluorine-containing compounds often occurs because the residues within the process chamber vary in thickness and therefore have different cleaning times. Thus, certain areas of the process chamber's interior may become residue-free (i.e., exposed) before others, resulting in the formation of an aluminum fluoride residue on the exposed portions of the chamber's interior.
Therefore, the prior art is deficient in the lack of effective means of cleaning a process chamber in chemical vapor deposition (CVD) or etching processes. In particular, the cleaning means should be capable of removing the residues created during substrate processing operations, while reducing or eliminating the subsequent formation of cleaning residues such as polymers and aluminum fluoride. Specifically, the prior art is deficient in the lack of effective means of chamber cleaning via rapid thermal process during the cleaning period. The present invention fulfills these long-standing needs and desires in the art.
SUMMARY OF THE INVENTION
In one embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of introducing at least one cleaning gas to the process chamber; and employing a rapid heating module located in the process chamber, wherein the rapid heating module increases the temperature of chamber parts and improves the surface temperature uniformity of chamber parts when the module is turned on, thereby assisting the cleaning activity of the cleaning gas such that the process chamber is cleaned.
In one embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of introducing at least one halogen-containing gas to the process chamber; and employing a rapid heating module located in the process chamber, wherein the rapid heating module comprises a high power lamp assembly, a resistive heater assembly, an inductive heater assembly, or a combination of two or more of the assemblies, wherein the rapid heating module increases the temperature of chamber parts and improves the surface temperature uniformity of chamber parts when the module is turned on, thereby assisting the cleaning activity of the cleaning gas such that the process chamber is cleaned.
In one embodiment of the present invention there is provided a method for cleaning a process chamber, comprising the steps of introducing at least one fluorine-containing gas to the process chamber; and employing a rapid heating module located in the process chamber, wherein the rapid heating module comprises a high power
Applied Materials Inc.
Markoff Alexander
Moser Patterson & Sheridan LLP
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