Patent ID: 12252785

It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of illustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below.

Processes for forming NMOS devices may form films such as group5layers or a combination thereof. To accomplish this, the processes may use chemical precursors such as arsine or phosphine, or any halogenated or alkyl-substituted variant thereof. The residue may comprise arsenic, phosphorous, arsenic compounds (AsXn), phosphorous compounds (PXn), arsenic trichloride, arsenic dichloromonohydride, or phosphorous chloride, for example. For residues involving chemicals like arsenic, for example, the residue can cause serious health problems to equipment engineers during tool maintenance. Embodiments of the invention are directed to minimize the presence of arsenic, phosphorous, and germanium chemicals and compounds to near zero concentrations to meet standards set by the American Conference of Governmental Industrial Hygienists threshold value limits for the occupational exposure limit. These concentrations may be met in less time, in approximately 10 to 60% of existing outgassing wait times, allowing for greater productivity. Owing to complete coating removal, the equipment engineer's exposure to dust and residue is also greatly reduced. Following the clean, arsine and chlorine on the equipment engineer is below the occupational exposure limit of 0.005 and 0.5 parts per million (ppm), respectively.

Furthermore, embodiments of the invention are directed to increasing the lifetime of quartz chambers before they would need to be either replaced or refurbished. Embodiments of the invention could allow for potentially as many as 10,000 to 30,000 wafers to be processed prior to replacement. Such an extension in chamber lifetime is critical given industry shortages in quartz chamber availability.

FIG.1illustrates a process100in accordance with at least one embodiment of the invention. The process100comprises: (1) a protective pre-coating step110; (2) a high temperature baking step120; and (3) a gas etching step130. The protective pre-coating step110may be required depending on a gas used in the gas etching step130. The protective pre-coating step110may be used to protect parts within the reaction chamber. For example, particular parts in the reaction chamber may be made of silicon carbide (SiC) or graphite. Prolonged exposure to particular gaseous halides may result in damage to the SiC or graphite parts. The protective pre-coating step110would prevent this damage from prolonged exposure.

The protective pre-coating step110may comprise a flow of a chemical precursor, such as at least one of: dichlorosilane (DCS), trichlorosilane (TCS), silane (SiH4), or disilane (Si2H6). The chemical precursor would form a layer onto the SiC or graphite parts of the chamber as well as the quartz walls. The temperature of the reaction chamber during the protective pre-coating step110may range between 750-950° C. The protective pre-coating step110may continue until a layer of the precursor forms a thickness exceeding 35 nm, 40 nm, or 45 nm. The duration of the protective pre-coating step110may exceed 180 s, 210 s, or 240 s.

The high temperature baking step120comprises heating the reaction chamber to temperatures in excess of 700° C., 800° C., or 900° C. The reason for the high temperature baking step120may include heating the reaction chamber, especially at peripheral regions, to enable effective etching chemistry. The high temperature bake step may also add in decoupling the susceptor temperature from that of the chamber. The duration of the high temperature baking step120may exceed 160 s, 170 s, or 180 s. The high temperature baking step120results in a hot quartz chamber, which may result in an easier removal of the residue during the gas etching step130.

The gas etching step130may comprise flowing a gas including at least one of: chlorine (Cl2) or nitrogen (N2). In those situations where chlorine is used, this would obviate the need for hydrochloric acid (HCl) within the chamber, leading to safer conditions for operators of the tool. The pressure of the gas etching step130may range between 40-100 Torr, 45-90 Torr, or 50-85 Torr. The duration of the gas etching step130may range from 1 to 10 minutes, 1.5 to 7 minutes, or 2 to 5 minutes. The gas flowed during the gas etching step130may react with the residue to form chlorine-substituted arsenic, germanium, silicon, or phosphorous, or any chlorinated derivative thereof. This can be easily purged from the reaction chamber by flowing an inert gas, such as nitrogen, argon, or krypton, for example.

FIG.2illustrates an exemplary reaction system200in accordance with at least one embodiment of the invention. The reaction system200comprises: a reaction chamber housing210; a wafer holder220that is configured to hold a substrate230; a first gas source240; a second gas source250; a third gas source260; an inlet gas line270; an outlet gas line280; an exhaust290; a pyrometer300; and a pressure control valve310. The first gas source240may be configured to flow a reaction gas used to form a film on the substrate230. The second gas source250may be configured to flow another reaction gas used to form a film on the substrate230or may be configured to flow a purge gas. The third gas source260may be configured to flow an etchant gas.

The gases from the first gas source240, the second gas source250, and the third gas source260may flow through the inlet gas line270into the reaction chamber housing210. Any remaining gas may be purged out through the outlet gas line280into the exhaust290. Additional gas sources may be employed with additional inlet gas lines. Likewise, additional exhausts may be employed with additional outlet gas lines.

The pyrometer300may be embedded in the reaction chamber housing210. The pyrometer300may be configured to measure a temperature within the reaction chamber housing210. The pressure control valve310may be configured to control the pressure within the reaction chamber housing210.

Running of the processes described above may improve the functioning of the pyrometer300and the pressure control valve310. Both the pyrometer300and the pressure control valve310may have its performance adversely affected by accumulation of films during a film deposition process. Cleaning processes such as the one shown inFIG.1may remove coating, which otherwise would impede accurate readings from the pyrometer300and the pressure control valve310. The cleaning process is also able to remove coating in the exhaust foreline280which may extend the on-tool lifetime of the foreline components280or enable safe disassembly of foreline components280.

The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationship or physical connections may be present in the practical system, and/or may be absent in some embodiments.

It is to be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various acts illustrated may be performed in the sequence illustrated, in other sequences, or omitted in some cases.

The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.