1. Field
Embodiments of the disclosure generally relate to the field of semiconductor manufacturing equipment, and more specifically, an apparatus for gas injection to an epitaxial chamber.
2. Description of the Related Art
Size reduction of metal-oxide-semiconductor field-effect transistors (MOSFETs) has enabled the continued improvement in speed, performance, density, and cost per unit function of integrated circuits. The semiconductor industry is also in the era of transitioning from 2D transistors, which are often planar, to 3D transistors using a three-dimensional gate structure. In 3D gate structures, the channel, source and drain are raised out of the substrate and the gate is then wrapped around the channel on three sides. The goal is to constrain the current to only the raised channel, and abolish any path through which electrons may leak. One such type of 3D transistors is known as a FinFET (fin field-effect transistor), in which the channel connecting the source and drain is a thin “fin” extending from of the substrate, thereby constraining the current to the channel. As a result, electrons may be prevented from leaking.
Selective epitaxial deposition processes have been used by the industry to form epitaxial layers of silicon-containing materials, elevated source/drain structures, or source/drain extensions needed in the 3D transistors. Generally, a selective epitaxial process involves a deposition reaction and an etch reaction. Chlorine gas can be used as an etching chemical in the selective epitaxial process to achieve the process selectivity by etching away an amorphous film on dielectrics and defective epitaxial films, or during a chamber cleaning process to remove remaining deposition gases or deposited residues from chamber components. Chlorine gas generally exhibits a high degree of reactivity and can easily react with deposition process gases (which typically contain hydrogen and hydrides) even at low temperature. However, in conventional processes, the chlorine gas and the deposition process gases are normally not used together during the deposition phase to avoid affecting the film growth rate. While film growth rate or deposition efficiency of the deposition process gases can be controlled or manipulated by performing deposition reactions alternately with etching reactions, or separately introducing the etching chemical and deposition process gases into the reaction chamber with controlled time and process conditions, such approaches are complicated and time consuming, which in turn affects the throughput and overall productivity of the processing system.
Therefore, what is needed are improved gas injection apparatus capable of enabling simultaneous processes that can react etch chemicals with deposition process gases.
In one embodiment, a gas distribution manifold liner apparatus is provided which includes an inject liner. The inject liner comprises a first surface having a first plurality of outlets formed therein. One or more of the first plurality of outlets may be angled upward toward the first plurality of outlets relative to an axis. A second surface may have a second plurality of outlets formed therein. The second plurality of outlets may be disposed coplanar with the first plurality of outlets.
In another embodiment, a gas distribution manifold liner apparatus is provided which includes an inject liner. The inject liner comprises a first surface having a first plurality of outlets formed therein. One or more of the first plurality of outlets may be angled upward toward the first plurality of outlets relative to an axis. A second surface may have a second plurality of outlets formed therein. The second plurality of outlets may be disposed below the first plurality of outlets. A third surface may have the first plurality of outlet formed therein. The third surface may be coplanar with the first surface. One or more of the first plurality of outlets formed in the third surface may be angled upward relative to the axis.
In yet another embodiment, a gas distribution manifold liner apparatus is provided which includes an inject liner. The inject liner comprises a first surface having a first plurality of outlets formed therein, one or more of the first plurality of outlets may be angled upward the first plurality of outlets relative to an axis. A second surface may have a second plurality of outlets formed therein. The second plurality of outlets may be disposed below the first plurality of outlets.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized in other embodiments without specific recitation.
Embodiments described herein generally relate to apparatus for forming silicon epitaxial layers on semiconductor devices. Deposition gases and etching gases may be provided sequentially or simultaneously to improve epitaxial layer deposition characteristics. A gas distribution assembly may be coupled to a deposition gas source and an etching gas source. Deposition gas and etching gas may remain separated until the gases are provided to a processing volume in a processing chamber. Outlets of the gas distribution assembly may be configured to provide the deposition gas and etching gas into the processing volume with varying characteristics. In one embodiment, outlets of the gas distribution assembly which deliver etching gas to the processing volume may be angled upward relative to a surface of a substrate.
The chamber 100 includes a housing structure 102 made of a process resistant material, such as aluminum or stainless steel. The housing structure 102 encloses various functioning elements of the process chamber 100, such as a quartz chamber 104, which includes an upper chamber 106, and a lower chamber 108, in which a processing volume 110 is defined. A substrate support 112, which may be made of a ceramic material or a graphite material coated with a silicon material, such as silicon carbide, is adapted to receive a substrate 114 within the quartz chamber 104. Reactive species from precursor reactant materials are applied to a processing surface 116 of the substrate 114, and byproducts may be subsequently removed from the processing surface 116. Heating of the substrate 114 and/or the processing volume 110 may be provided by radiation sources, such as upper lamp modules 118A and lower lamp modules 118B. In one embodiment, the upper lamp modules 118A and lower lamp modules 118B are infrared lamps. Radiation from the lamp modules 118A and 118B travels through an upper quartz window 120 of the upper chamber 106, and through a lower quartz window 122 of the lower chamber 108. Cooling gases for the upper chamber 106, if needed, enter through an inlet 124 and exit through an outlet 126.
Reactive species are provided to the quartz chamber 104 by a gas distribution assembly 128. Processing byproducts are removed from the processing volume 110 by an exhaust assembly 130, which is typically in communication with a vacuum source (not shown). Precursor reactant materials, as well as diluent, purge and vent gases for the chamber 100, enter through the gas distribution assembly 128 and exit through the exhaust assembly 130. The chamber 100 also includes multiple liners 132A-132H (only liners 132A-132G are shown in
A lower liner 132A is disposed in the lower chamber 108. An upper liner 132B is disposed at least partially in the lower chamber 108 and is adjacent the lower liner 132A. An exhaust insert liner assembly 132C is disposed adjacent the upper liner 132B. In
The one or more gases are provided to the processing volume 110 from the first gas source 135A and the second gas source 135B. The first gas source 135A may be provided to the processing volume 110 via a pathway through an inject cap 129 and the second gas source 135B may be provided to the processing volume 110 through the baffle liner 132G. Although not shown, the first gas source 135A may be provided to the processing volume 110 through a second baffle liner or the baffle liner 132G if the first and second gases are kept separate until the gases reach the processing volume 110.
One or more first valves 156A may be formed on one or more first conduits 155A which couple the first gas source 135A to the chamber 100. Similarly, one or more second valves 156B may be formed on one or more second conduits 155B which coupled the second gas source 135B to the chamber 100. The valves 156A, 156B may be adapted to control the flow of gas from the gas sources 135A, 135B. The valves 156A, 156B may be any type of suitable gas control valve, such as a needle valve or a pneumatic valve. The valves 156A, 156B may control gas flow from the gas sources 135A, 135B in a desirable manner. In one embodiment, the one or more first valves 156A may be configured to provide a greater flow of gas from the first gas source 135A to a center region of the substrate 114. Each of the valves 156A, 156B may be controlled independently of one another and each of the valves 156A, 156B may be at least partially responsible for determining gas flow within the processing volume 110.
Gas from both the first gas source 135A and the second gas source 135B may travel through the through the one or more openings 136A and 136B formed in the injector liner 132E. In one embodiment, gas provided from the first gas source 135A may travel through the opening 136A and gas provided from the second gas source 135B may travel through the opening 136B. In another embodiment, the first gas source 135A may provide an etching gas and the second gas source 135B may provide a deposition gas.
The one or more openings 136A and 136B formed in the injector liner 132E are coupled to outlets configured for a laminar flow path 133A or a jetted flow path 133B. The openings 136A and 136B may be configured to provide individual or multiple gas flows with varied parameters, such as velocity, density, or composition. In one embodiment where multiple openings 136A and 136B are adapted, the openings 136A and 136B may be distributed along a portion of the gas distribution assembly 128 (e.g., injector liner 132E) in a substantial linear arrangement to provide a gas flow that is wide enough to substantially cover the diameter of the substrate. For example, each of the openings 136A and 136B may be arranged to the extent possible in at least one linear group to provide a gas flow generally corresponding to the diameter of the substrate. Alternatively, the openings 136A and 136B may be arranged in substantially the same plane or level for flowing the gas(es) in a planar, laminar fashion, as discussed below with respect to
Each of the flow paths 133A, 133B are configured to flow across an axis A′ in a laminar or non-laminar flow fashion to the exhaust liner 132D. The flow paths 133A, 133B may be generally coplanar with the axis A′ or may be angled relative to the axis A′. For example, the flow paths 133A, 133B may be angled upward or downward relative to the axis A′. The axis A′ is substantially normal to a longitudinal axis A″ of the chamber 100. The flow paths 133A, 133B flow into a plenum 137 formed in the exhaust liner 132D and culminate in an exhaust flow path 133C. The plenum 137 is coupled to an exhaust or vacuum pump (not shown). In one embodiment, the plenum 137 is coupled to a manifold 139 that directs the exhaust flow path 133C in a direction that is substantially parallel to the longitudinal axis A″. At least the inject insert liner assembly 132F may be disposed through and partially supported by the inject cap 129.
In one embodiment, each of the inject insert liner assembly 132F and the exhaust insert liner assembly 132C comprise two sections. The inject insert liner assembly 132F includes a first section 206A and a second section 206B that are coupled at one side by the baffle liner 132G. Likewise, the exhaust insert liner assembly 132C includes a first section 208A and a second section 208B. Each of the sections 206A and 206B of the inject insert liner assembly 132F receive gases from the first gas source 135A and the second gas source 135B through the baffle liner 132G. Gases are flowed through the inject insert liner assembly 132F via the first plurality of passages 190 and the second plurality of passages 192 and are routed to a plurality of first outlets 210A and a plurality of second outlets 210B in the injector liner 132E. In one aspect, the inject insert liner assembly 132F and the injector liner 132E comprise a gas distribution manifold liner. Thus, the gases from the first gas source 135A and the second gas source 135B are flowed separately into the processing volume 110. In one example, gas provided from the first gas source 135A is provided to the processing volume 110 via the plurality of first outlets 210A and gas provided from the second gas source 135B is provided to the processing volume 110 via the plurality of second outlets 210B. Each of the gases may be dissociated before, during or after exiting the outlets 210A, 210B and flow across the processing volume 110 for deposition on a substrate (not shown). The dissociated precursors remaining after deposition are flowed into the exhaust insert liner assembly 132C and exhausted.
The liners 132A-132H may be installed and/accessed within the chamber 100 of
The exhaust insert liner assembly 132C, the inject insert liner assembly 132F, and the slit valve liner 132H may be installed after the lower liner 132A is positioned on the lower quartz window 122. The inject insert liner assembly 132F may be coupled with the baffle liner 132G to facilitate gas flow from the first gas source 135A and the second gas source 135B. The upper liner 132B may be installed after installation of the exhaust insert liner assembly 132C, the inject insert liner assembly 132F, and the slit valve liner 132H. The annular pre-heat ring 140 may be positioned on the inwardly extending shoulder 138 of the upper liner 132B. The injector liner 132E may be installed within an aperture formed in the upper liner 132B and coupled with the inject insert liner assembly 132F to facilitate gas flow from the inject insert liner assembly 132F to the injector liner 132E. The exhaust liner 132D may be installed above the exhaust insert liner assembly 132C within an aperture formed in the upper liner 132B opposite the injector liner 132E. In some embodiments, the injector liner 132E may be replaced with another injector liner configured for a different gas flow scheme. Likewise, the exhaust insert liner assembly 132C may be replaced with another exhaust insert liner assembly configured for a different exhaust flow scheme.
Process gases from the first gas source 135A and the second gas source 135B are flowed through the inject cap 129. The inject cap 129 includes multiple gas passageways that are coupled to ports (not shown) formed in the baffle liner 132G. In one embodiment, lamp modules 305 may be disposed in the inject cap 129 to preheat precursor gases within the inject cap 129. The baffle liner 132G includes conduits (not shown) that flow the gases into the inject insert liner assembly 132F. The inject insert liner assembly 132F includes ports (not shown) that route gases to the first outlets 210A and the second outlets 210B of the gas distribution manifold liner 300. In one embodiment, the gases from the first gas source 135A and the second gas source 135B remain separated until the gases exit the first outlets 210A and the second outlets 2108, respectively.
In one aspect, the gases are preheated within the inject cap 129 and one or more of the baffle liner 132G, the inject insert liner assembly 132F, and the gas distribution manifold liner 300. The preheating of the gases may be provided by one or combination of the lamp modules 305 on the inject cap 129, the upper lamp modules 118A, and the lower lamp modules 118B (both shown in
Referring back to
Referring back to
In one aspect, the dual zone injection provided by the first injection zone 410A and the second injection zone 410B facilitates a varied level of injection for different gases. In one embodiment, the first injection zone 410A and the second injection zone 410B is spaced-apart in different planes to provide a precursor to the processing volume 110 (shown in
The extended member 605 includes a portion of the first outlets 210A while the remainder of the first outlets 210A are disposed in the first surface 420A of the gas distribution manifold liner 600. In one embodiment, a greater density of first outlets 210A may be formed in the extended member 605 as opposed to the first plurality of outlets 210A disposed on the first surface 420A. For example, the density of the first outlets 210A disposed on the third surface 610 may be between about 1.1 and about 5 times greater than the density of the first outlets 210A disposed on the first surface 420A. As such, spacing between the first outlets 210A on the third surface 610 may be less than the spacing between the first outlets 210A on the first surface 420A.
In one embodiment, the first outlets 210A on the third surface 610 may be spaced apart evenly. In another embodiment, the first outlets 210A on the third surface 610 may be variably spaced. For example, spacing of the first outlets 210A near a center region 602 of the extended member 605 may be less than the spacing of the first outlets 210A near edge regions 604 of the extended member 605. Accordingly, a greater density of first outlets 210A may be formed at the center region 602 of the extended member 605. It is contemplated that increasing the density of the first outlets 210A on the third surface 610 of the extended member 605 may provide for improved gas delivery to a center region of the substrate 114. It is contemplated that the feature of first outlet density may be incorporated on any of the gas distribution manifold liners 300, 400, 500 depicted in
One or a combination of the flow paths provided by the first outlets 210A and the second outlets 210B enables deposition uniformity and uniform growth across the substrate (not shown). In one embodiment, the first outlets 210A of the extended member 605 are utilized to inject precursor gases that tend to dissociate faster than precursors provided by the second outlets 210B. For example, Cl2 may be provided by the first outlets 210A given the high dissociation characteristics of chlorine gas. This provides an extended flow path to inject the faster dissociating precursor a further distance and/or closer to the center of the substrate 114. Thus, the combination of precursors from both of the first outlets 210A and the second outlets 210B provides uniform distribution and growth across the substrate 114.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
This application claims benefit of U.S. Provisional Patent Application No. 62/014,741, filed Jun. 20, 2014, the entirety of which is herein incorporated by reference.
Number | Date | Country | |
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62014741 | Jun 2014 | US |