Method for processing epitaxial semiconductor wafers

Abstract

A method for processing a semiconductor wafer includes placing a semiconductor wafer in a recess of a susceptor within a heating chamber. The recess is defined in the susceptor by a downwardly extending sidewall. The method also includes determining a distance from the sidewall to a peripheral edge of the wafer. The method also includes supplying a first process gas into the heating chamber at a first gas flow rate, supplying a second process gas into the heating chamber at a second gas flow rate, and supplying heat to the heating chamber. The method also includes adjusting the first gas flow rate, the second gas flow rate, and / or the heat supplied to the heating chamber to control a deposition rate of the first process gas and the second process gas near the peripheral edge of the wafer based on the determined distance from the sidewall to the peripheral edge of the wafer.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 477,960, filed December 30, 2022, the entire disclosure of which is incorporated by reference.

[0002] The field of the disclosure relates generally to semiconductor wafer processing, and more particularly to adjusting processing conditions during epitaxial processing based on the placement position of a semiconductor wafer on a susceptor of an epitaxial chamber. [Background technology]

[0003] Epitaxial chemical vapor deposition is a process for growing thin layers of material on semiconductor wafers that have the same lattice structure as the wafer. Using this process, layers of different conductivity types, dopant species, or dopant concentrations can be applied to the semiconductor wafer to achieve desired electrical properties.

[0004] Prior to epitaxial growth, a semiconductor wafer is typically placed on a susceptor within the reactor's growth chamber. The epitaxial growth process begins by introducing a cleaning gas onto the front surface of the wafer to preheat the wafer's front surface. The cleaning gas removes native oxide from the front surface, allowing an epitaxial silicon layer to be grown continuously and uniformly on the surface in subsequent deposition process steps. The epitaxial growth process continues by introducing a vaporized silicon source gas (e.g., trichlorosilane, SiHCl3) onto the front surface of the wafer to deposit and grow an epitaxial layer of silicon on the front surface. The back surface, opposite the front surface of the susceptor, may be simultaneously exposed to hydrogen gas. During epitaxial growth, the susceptor supporting the semiconductor wafer within the growth chamber is rotated during the process to ensure uniform growth of the epitaxial layer.

[0005] In recent years, there has been an increasing demand for epitaxial semiconductor wafers with uniform thickness and flatness across the wafer, particularly for wafers used in the manufacture of complementary metal-oxide semiconductor (CMOS) and integrated circuit devices. Conventional systems and methods for epitaxial processing of semiconductor wafers remain limited in their ability to effectively and / or consistently produce the desired thickness and flatness uniformity of deposited epitaxial layers. For example, conventional systems and methods may not adequately compensate for various factors in the epitaxial growth process that adversely affect the thickness of epitaxial layers deposited near the wafer's periphery. As a result, edge roll-off can occur along the wafer's deposition surface near the periphery, reducing the thickness and flatness uniformity of the epitaxial wafer.

[0006] What is needed is a system and method that helps mitigate edge roll-off effects during epitaxial processing of semiconductor wafers and improves thickness and flatness uniformity of epitaxial semiconductor wafers.

[0007] This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. As such, it should be read in this light, and not as admissions of prior art. Summary of the Invention

[0008] One aspect is a method for processing a semiconductor wafer in a heating chamber including a susceptor for supporting the semiconductor wafer. The susceptor has a front surface and a recess defined in the front surface by downwardly extending sidewalls. The method includes placing the semiconductor wafer in the recess and determining a distance from the sidewall of a peripheral edge of the wafer. The method also includes supplying a first process gas into the heating chamber at a first gas flow rate in a first gas direction and supplying a second process gas into the heating chamber at a second gas flow rate in a second gas direction intersecting the first gas direction. The method also includes supplying heat to the heating chamber to induce deposition of the first process gas and the second process gas on the wafer surface. The method also includes adjusting at least one of the first gas flow rate, the second gas flow rate, and the heat supplied to the heating chamber to control a deposition rate of the first process gas and the second process gas near the peripheral edge of the wafer based on the determined distance from the sidewall of the peripheral edge of the wafer.

[0009] Another aspect is a method for processing a semiconductor wafer in a heating chamber including a susceptor for supporting the semiconductor wafer. The susceptor has a front surface and a recess defined in the front surface by downwardly extending sidewalls. The method includes placing the semiconductor wafer in the recess of the susceptor. The method also includes determining a peripheral region of the wafer that is located a minimum distance from the sidewall. The method also includes supplying a first process gas into the heating chamber at a first gas flow rate in a first gas direction and supplying a second process gas into the heating chamber at a second gas flow rate in a second gas direction intersecting the first gas direction. The method also includes adjusting at least one of the first gas flow rate and the second gas flow rate to selectively increase deposition rates of the first process gas and the second process gas near the peripheral region of the wafer that is located a minimum distance from the sidewall.

[0010] Another aspect is a method for processing a semiconductor wafer in a heating chamber including a susceptor for supporting the semiconductor wafer. The susceptor has a front surface and a recess defined in the front surface by a downwardly extending sidewall. The method includes placing the semiconductor wafer in the recess of the susceptor. The method also includes determining a peripheral region of the wafer located a minimum distance from the sidewall. The method also includes supplying a process gas to the heating chamber and supplying heat to the heating chamber to induce deposition of the process gas on a surface of the wafer. The method also includes adjusting the heat supplied to the heating chamber to selectively increase the deposition rate of the process gas near the peripheral region of the wafer located a minimum distance from the sidewall.

[0011] Various refinements exist to the features described in connection with the above-described aspects of the present disclosure. Additional features may be incorporated into the above-described aspects. These refinements and additional features may exist individually or in any combination. For example, the various features described below in connection with any of the illustrated embodiments may be incorporated into any of the above-described aspects, alone or in any combination. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic cross-sectional view of a heat chamber for semiconductor wafer processing. [Figure 2] FIG. 2 is a schematic cross-sectional view of the heating chamber of FIG. 1 with elements omitted to show in greater detail a semiconductor wafer supported on a susceptor. [Figure 3] FIG. 3 is a schematic top view of the heating chamber of FIG. 1 with elements removed to show in more detail a semiconductor wafer supported on a susceptor. [Figure 4] FIG. 4 is a process flow of an example of a semiconductor wafer processing method. [Figure 5] FIG. 5 is a graph illustrating the adjustment of localized heating within a heat chamber based on the distance between the periphery of a semiconductor wafer and the sidewall of a recess in a susceptor within the heat chamber. [Figure 6]FIG. 6 is a graph conceptually illustrating the normalized edge roll-off of an epitaxial wafer that may be processed with and without the localized heating adjustment shown in FIG. [Figure 7] FIG. 7 is a graph illustrating adjustment of the flow rate of trichlorosilane process gas within a heating chamber based on the distance between the periphery of a semiconductor wafer and the sidewall of a recess in a susceptor within the heating chamber. [Figure 8] FIG. 8 is a graph conceptually illustrating the normalized edge roll-off of epitaxial wafers that may be processed with and without the adjustment of the trichlorosilane gas flow rate shown in FIG. [Figure 9] FIG. 9 is a graph illustrating adjustment of the flow rate of hydrogen chloride process gas within a heating chamber based on the distance between the periphery of a semiconductor wafer and the sidewall of a recess in a susceptor within the heating chamber. [Figure 10] FIG. 10 is a graph conceptually illustrating the normalized edge roll-off of epitaxial wafers that may be processed with and without the hydrogen chloride gas flow rate adjustment shown in FIG.

[0013] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring to FIG. 1 , an example of a heating chamber 100 for use in accordance with the present disclosure is shown. The heating chamber 100 may be a processing reactor, such as a deposition reactor or thermal processing reactor, including a vapor phase epitaxy processing reactor, for processing semiconductor wafers. The heating chamber 100 is an example, and unless otherwise specified, any reactor capable of processing semiconductor wafers (e.g., facilitating deposition of an epitaxial layer on a surface of a semiconductor wafer) in accordance with the methods of the present disclosure may be used. In some examples, the heating chamber 100 may be a Centura Epi reactor available from Applied Materials, Inc. (Santa Clara, California).

[0015] Chamber 100 includes a processing environment 102 in which a single semiconductor wafer 104 is processed. For example, chamber 100 may be suitable for semiconductor wafer processing, such as chemical vapor deposition (CVD) (i.e., epitaxial growth) of thin films on wafer 104. Other suitable semiconductor wafer processing operations for chamber 100 include, for example, heating wafer 104, cleaning wafer 104, and / or etching wafer 104. Chamber 100 may also be suitable for processing multiple (i.e., two or more) semiconductor wafers 104 simultaneously.

[0016] Suitable semiconductor wafers 104 (sometimes referred to as "wafers" or "silicon wafers") include monocrystalline silicon wafers, such as silicon wafers obtained by slicing silicon wafers from an ingot formed by the Czochralski or float zone processes. Each semiconductor wafer 104 includes a front surface 142 and a back surface 144 that is substantially parallel to the front surface 142. The front surface 142 and the back surface 144 are generally perpendicular to the central axis of the wafer 104. A circumferential edge or rim 146 joins the front surface 142 and the back surface 144. The semiconductor wafers 104 may have any suitable diameter, including, for example, a diameter of 150 millimeters (mm), 200 mm, 300 mm, or 450 mm.

[0017] The chamber 100 includes a first gas injection port 106a located at one end of the processing environment 102 and a gas exhaust port 108 located at the opposite end of the processing environment 102. The chamber 100 also includes a second gas injection port 106b (shown in FIG. 3) located between the first gas injection port 106a and the gas exhaust port 108. A gas manifold (not shown) located between the gas injection ports 106a, 106b and the processing environment 102 is used to direct an inlet gas 110 through the first gas injection port 106a and the second gas injection port 106b into the processing environment 102, which is surrounded by an upper window 112 and a lower window 114.

[0018] During operation, input process gas 110 flows through the gas manifold and enters the processing environment 102 through gas inlets 103 defined by each of the gas injection ports 106a, 106b. The gas 110 flows through the processing environment 102 and is exhausted through the gas exhaust port 108. The process gases 110 flowing through the inlets 103 defined by each of the gas injection ports 106a, 106b can be the same or different.

[0019] The chamber 100 includes a susceptor 120 within the processing environment 102 for supporting a semiconductor wafer 104. The susceptor 120 is preferably configured to rotate the semiconductor wafer 104 during processing. For example, as shown in FIG. 3 , the susceptor 120 is connected to a shaft 122, which is connected to a motor (not shown) of a rotation mechanism (not shown) for rotating the shaft 122, the susceptor 120, and the semiconductor wafer 104 about a vertical axis V of the chamber 100. The susceptor 120 may rotate the semiconductor wafer 104 at any suitable rotational speed. For example, the susceptor 120 and the semiconductor wafer 104 may rotate at a rotational speed between 1 RPM and 100 RPM. Additionally and / or alternatively, the susceptor 120 may be attached to a pair of rotatable supports (not shown) for rotating the susceptor 120 during processing.

[0020] The chamber 100 may also include a preheat ring 126 that surrounds the susceptor 120 within the processing environment 102. The preheat ring 126 may raise the process gas to a predetermined temperature before contacting the semiconductor wafer 104. An outer edge 124 of the susceptor 120 and an inner edge of the preheat ring 126 are separated by an annular gap 125 to allow rotation of the susceptor 120. The semiconductor wafer 104 is rotated within the chamber 100 to uniformly process the wafer.

[0021] The inlet gas 110 may be heated before contacting the semiconductor wafer 104. Both the preheat ring 126 and the susceptor 120 are generally opaque to absorb radiant heating light generated by high-intensity radiant heat lamps 128, which may be positioned above and below the processing environment 102. Devices other than the high-intensity lamps 128, such as resistive heaters and induction heaters, may be used to provide heat to the processing environment 102. Maintaining the preheat ring 126 and the susceptor 120 at a temperature above ambient temperature allows the preheat ring 126 and the susceptor 120 to transfer heat to the inlet gas 110 as the gas 110 passes over them. The diameter of the semiconductor wafer 104 is preferably smaller than the diameter of the susceptor 120 so that the susceptor 120 can heat the inlet gas 110 before it contacts the semiconductor wafer 104. The preheat ring 126 and susceptor 120 may be constructed of, for example, silicon carbide or opaque graphite coated with silicon carbide.

[0022] An infrared temperature sensor (e.g., sensor 188), such as a pyrometer, may be mounted in the reaction chamber 100 to receive infrared radiation emitted by the susceptor, preheat ring, and / or wafer and monitor the temperature of the susceptor 120, preheat ring 126, and / or semiconductor wafer 104.

[0023] The upper and lower windows 112, 114 each have a generally annular body made of a transparent material, such as quartz, that allows radiant heating light to enter the processing environment 102 and irradiate the preheat ring 126, the susceptor 120, and the semiconductor wafer 104. The windows 112, 114 may be planar, or as shown in FIG. 1 , the windows 112, 114 may have a generally dome-shaped configuration. One or both of the windows 112, 114 may alternatively have an inwardly recessed configuration. The upper and lower windows 112, 114 are coupled to an upper and lower chamber wall 130, 132, respectively, of the chamber 100.

[0024] An upper chamber wall 130 and a lower chamber wall 132 define the perimeter of the processing environment 102 and abut the gas inlet ports 106 a , 106 b and the gas outlet port 108 .

[0025] The chamber 100 may include an upper liner 134 and a lower liner 136 disposed within the processing chamber to prevent reaction between the gas 110 and the chamber walls 130, 132 (which may be made of a metallic material such as stainless steel). The liners 134, 136 may be made of a suitable non-reactive material such as quartz. The outer periphery of the preheat ring 126 may be attached to the inner periphery of the lower liner 136. For example, the preheat ring 126 may be supported by an annular ledge 160 of the lower liner 136.

[0026] 2 and 3 show in more detail the semiconductor wafer 104 supported on the susceptor 120 within the heating chamber 100. FIG. 2 is a cross-sectional view of the heating chamber 100, and FIG. 3 is a top view of the heating chamber 100. Elements of the chamber 100 have been omitted from FIGS. 2 and 3 for ease of illustration and explanation.

[0027] 2 and 3, the susceptor 120 is substantially disk-shaped and includes a front surface 148 and a recess 150 formed in the front surface 148. The recess 150 is defined by a downwardly extending sidewall 152 at the front surface 148. The recess 150 is sized and shaped to receive a semiconductor wafer 104 during processing. For example, as shown in FIG. 3, the recess 150 is substantially circular and defined by a substantially annular sidewall 152. The susceptor 120 may have other overall dimensions without departing from the scope of the present disclosure. The susceptor 120 may be sized and configured such that the recess 150 of the susceptor 120 can accommodate semiconductor wafers 104 of any suitable diameter, including, for example, wafers 104 having a diameter of 150 mm, 200 mm, 300 mm, or 450 mm.

[0028] The semiconductor wafer 104 is placed in a recess 150 in the susceptor 120 and is supported by a ledge 154 that extends between a sidewall 152 and a recess floor 156. The wafer 104 is oriented within the recess 150 such that the ledge 154 supports a portion of the backside 144 of the wafer 104 adjacent the periphery 146. The ledge 154 slopes downwardly toward the recess floor 156 such that the floor 156 is spaced from the backside 144 of the wafer 104.

[0029] As shown in FIGS. 2 and 3 , when the semiconductor wafer 104 is positioned within the recess 150, the peripheral edge 146 of the wafer is spaced apart from the sidewall 152 of the susceptor 120. The semiconductor wafer 104 may be positioned within the recess 150 manually or using an automated wafer handling device, such as a robotic arm. The wafer 104 is not necessarily perfectly centered within the recess 150; the distance between the peripheral edge 146 and the sidewall 152 varies along the circumference of the wafer 104. The peripheral edge 146 of the wafer 104 is spaced apart from the sidewall 152 by a minimum distance D1 and a maximum distance D2. The minimum distance D1 and the maximum distance D2 differ due to off-center wafer positioning within the recess 150. The off-center wafer positioning may be due to, for example, wafer placement tolerances, wafer movement during placement, and / or thermal expansion.

[0030] 1-3 , in operation, the heating chamber 100, including the susceptor 120 and the wafer 104 supported on the susceptor 120, may be used for cleaning, etching, and / or growth steps of an epitaxial growth process. In an exemplary epitaxial growth process, an epitaxial silicon layer is grown on the front side 142 of the semiconductor wafer 104. In this example, the silicon wafer 104 is introduced into a processing environment 102 at atmospheric pressure and positioned on the susceptor 120. A cleaning gas, such as hydrogen, i.e., H2, or a mixture of H2 and an etchant gas (e.g., hydrogen chloride, HCl), is introduced as process gas 110 into the processing environment 102 through one or both of the first gas injection port 106a and the second gas injection port 106b to remove native oxide layers on the front side 142 and backside 144 of the semiconductor wafer 104.

[0031] After the native oxide layer is removed from both the front surface 142 and the back surface 144 of the semiconductor wafer 104, the supply of cleaning gas is discontinued, and the temperature within the heating chamber 100 is adjusted to a temperature suitable for the epitaxial growth process (e.g., between about 600°C and about 1200°C). A deposition precursor gas is introduced as the process gas 110 through one or both of the first gas injection port 106a and the second gas injection port 106b. The deposition precursor gas may be a silicon-containing gas. Examples of silicon-containing gases include methylsilane, silicon tetrahydrate (silane), trisilane, disilane, pentasilane, neopentasilane, tetrasilane, dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), silicon tetrachloride (SiCl4), and the like. The deposition precursor gas may also include other materials, such as other semiconductor materials, depending on the desired composition of the deposited epitaxial layer. The concentration of the gas may be determined based on the desired deposition effect (e.g., deposition rate). The deposition precursor gas flows over the front surface 142 of the semiconductor wafer 104 at an appropriate flow rate (e.g., between about 1 liter per minute and about 100 liters per minute) for a time sufficient to grow an epitaxial layer (e.g., an epitaxial silicon layer) on the front surface 302 of the semiconductor wafer 104. The epitaxial layer may have a thickness between about 0.1 and about 200 micrometers. The processing environment 102 may be at an appropriate pressure (e.g., atmospheric pressure) during deposition.

[0032] The process gas 110 introduced into the processing environment 102 during the deposition process may include a carrier gas, such as hydrogen, i.e., H (e.g., trichlorosilane in H), in addition to the deposition precursor gas. The carrier gas may additionally and / or alternatively include argon, nitrogen, helium, or a combination thereof. The carrier gas may contact the backside 144 of the semiconductor wafer 104 and carry dopant atoms outdiffused from the backside 144 toward the gas exhaust port 108. The process gas 110 may include an etchant gas, such as hydrogen chloride (HCl). The etchant gas may facilitate smoothing of the deposited epitaxial layer. The etchant gas may be generated in the processing environment by a reaction between the carrier gas and the deposition precursor gas. For example, if the process gas 110 includes trichlorosilane in H, HCl may be generated according to the following equation: SiHCl3(g) + H2(g) = Si(s) + 3HCl(g)

[0033] The distance between the periphery 146 and the sidewall 152 of the wafer 104 can cause edge roll-off of the epitaxial layer deposited near the periphery of the wafer 104, which affects the thickness and flatness uniformity of the wafer 104 after epitaxy. For example, a small distance between the periphery 146 and the sidewall 152 can result in less deposited material accumulating near the periphery 146 of the wafer 104 relative to the epitaxial layer deposited across the front surface 142. This can result in a "down-tick" in the deposited epitaxial layer near the periphery 146. Without being bound by theory, the down-tick in the deposited epitaxial layer along the region near where the periphery 146 is located a relatively small distance from the sidewall 152 can be attributed to less interaction between the process gas 110 and the periphery 146 and / or a relatively lower temperature at the periphery 146 due to a relatively lower temperature of the susceptor 120 at the sidewall 152. The increased distance between the periphery 146 and the sidewall 152 may result in a greater amount of deposited material accumulating near the periphery 146 of the wafer 104 relative to the epitaxial layer deposited across the front surface 142. This may result in an "uptick" in the deposited epitaxial layer near the periphery 146. Without being bound by any particular theory, the uptick in the deposited epitaxial layer along the region near where the periphery 146 is located a relatively greater distance from the sidewall 152 may be due to increased interaction between the process gas 110 and the periphery 146 due to more space for the process gas to flow between the wafer 104 and the sidewall 152.

[0034] Because epitaxial growth behavior varies depending on the distance between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120, off-center positioning of the wafer 104 within the recess 150 can affect the thickness and flatness uniformity of the wafer 104 after epitaxy. In other words, the edge roll-off of the deposited epitaxial layer can vary along the circumferential extent of the wafer 104 due to off-center positioning within the recess 150. For example, a relatively large amount of deposited epitaxial material can accumulate in an area on the front surface 142 of the wafer 104 near the periphery 146 where the wafer 104 is spaced a maximum distance D from the sidewall 152 (e.g., the area generally designated 194 in FIG. 3 ). An area on the front surface 142 of the wafer 104 near the periphery 146 where the wafer 104 is spaced a minimum distance D1 from the sidewall 152 (e.g., the area generally designated 192 in FIG. 3 ) may accumulate relatively little deposited epitaxial material. As a result, the deposited epitaxial layer may have upticks and downticks near the periphery 146 along the circumferential extent of the wafer 104, resulting in non-uniform thickness and reduced flatness of the wafer 104 after epitaxy.

[0035] 1-3 , the heating chamber 100 includes an optical sensor 158 for measuring the distance between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120. The optical sensor 158 is, for example, a camera. Preferably, the optical sensor 158 is positioned outside the processing environment 102 and above the top window 112. The optical sensor 158 may preferably measure the distance between the periphery 146 and the sidewall 152 over the entire or substantially entire circumferential extent of the wafer 104. For example, the optical sensor 158 may take a measurement at a single position between the periphery 146 and the sidewall 152 of the wafer 104, and the optical sensor 158 continues to collect measurements as the wafer 104 is placed in and rotated by the susceptor 120. Although one optical sensor 158 is shown in this example, more than one (i.e., two or more) optical sensors 158 may be included. Each optical sensor 158 may collect measurements at a different location between the perimeter 146 and the sidewall 152 .

[0036] The optical sensor 158 may collect measurements of the distance between the periphery 146 and the sidewall 152 in any suitable manner. For example, the optical sensor 158 may be connected to the controller 140, which may determine the distance between the periphery 146 and the sidewall 152 based on measurements collected by the optical sensor 158. Additionally or alternatively, the optical sensor 158 may be connected to a user interface that displays the collected measurements to an operator. The measurements collected by the optical sensor 158 may be in units of length (e.g., metric units such as mm) or relative units. For example, the optical sensor 158 may collect measurements in any units relative to a reference distance. Thus, references to “measuring a distance,” “determining a distance,” “collecting distance measurements,” etc., with respect to the distance between the periphery 146 and the sidewall 152 are not intended to be limited to a particular measurement technique. The measurements collected by the optical sensor 158 may determine areas along the circumferential extent of the wafer 104 where edge roll-off may occur. For example, measurements collected by optical sensor 158 can enable determination of a wafer region near periphery 146 where wafer 104 is spaced a minimum distance D1 from sidewall 152 (e.g., region 192 in FIG. 3 ), and a wafer region near periphery 146 where wafer 104 is spaced a maximum distance D2 from sidewall 152 (e.g., region 194 in FIG. 3 ).

[0037] In an exemplary method, processing conditions within the heating chamber 100 are controlled and / or adjusted (collectively, "adjusted"), e.g., using the controller 140, based on the determined distance between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120. The processing conditions may include, for example, the flow rate of the process gas 110 introduced into the processing environment 102 and / or the heat supplied to the processing environment 102. The processing conditions are adjusted to control the deposition rate of the process gas 110 near the periphery 146 of the wafer 104 based on the determined distance between the periphery 146 of the wafer 104 and the sidewall 152. This can enhance the uniformity of the thickness and flatness of the wafer 104 after epitaxy. For example, the processing conditions may be adjusted to increase the amount of deposited material on an area of ​​the wafer 104 near the periphery 146 where the wafer 104 is at a minimum distance D1 from the sidewall 152. The processing conditions may additionally or alternatively be adjusted to reduce the amount of deposited material on the area of ​​the wafer 104 near the periphery 146 where the wafer 104 is at a maximum distance D2 from the sidewall 152.

[0038] 1 , the heat chamber 100 includes a controller 140. The controller 140 is configured to control operation of the heat chamber 100 (e.g., by adjusting one or more processing conditions of the heat chamber). The controller 140 may be configured to control operation of the heat chamber 100, thereby controlling a deposition rate of the process gas 110 near the periphery 146 of the wafer 104, based on a determined distance between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120. For example, the controller 140 may adjust the flow rate of the process gas 110 introduced into the processing environment 102 and / or the heat supplied to the processing environment 102 based on the determined distance between the periphery 146 of the wafer 104 and the sidewall 152.

[0039] Controller 140 may include any suitable computer and / or processing unit, including any suitable combination of computers, processing units, and / or the like, communicatively coupled to each other and operable independently or in conjunction with each other (e.g., controller 140 may form all or part of a controller network). Controller 140 may include one or more modules or devices, one or more of which may be enclosed within a single housing or located remotely from each other. Controller 140 may include one or more processors and associated memory devices configured to perform various computer-implemented functions (e.g., perform the functions disclosed herein). As used herein, the term “processor” refers not only to integrated circuits, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application-specific integrated circuits, and other programmable circuits. Additionally, the memory device of the controller 140 may be or include a memory element, including, but not limited to, a computer-readable medium (e.g., random access memory (RAM)), a computer-readable non-volatile medium (e.g., flash memory), a floppy disk, a compact disk read-only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disk (DVD), and / or other suitable memory element. Such a memory device may be configured to store suitable computer-readable instructions that, when executed by a processor, are configured to cause the controller 140 to perform or cause the controller 140 to perform various functions described herein, including, but not limited to, controlling the operation of the heat chamber 100.

[0040] The controller 140 may communicate with one or more components of the heat chamber 100 (e.g., the optical sensor 158, one or more spot heating modules 170, one or more gas injection ports 106a, 106b, the gas manifold, one or more temperature sensors 188, the rotation mechanism of the susceptor 120, and / or other components) via a communication interface communicatively coupled to one or more of these components. The communication interface may include, but is not limited to, a wired network adapter, a wireless network adapter, a mobile telecommunications adapter, a serial communication adapter, or a parallel communication adapter. The communication interface may receive data signals from or transmit data signals to one or more components of the heat chamber 100 (e.g., the optical sensor 158, one or more spot heating modules 170, one or more gas injection ports 106a, 106b, the gas manifold, one or more temperature sensors 188, the rotation mechanism of the susceptor 120, and / or other components). The controller 140 may include a presentation interface coupled to one or more processors. The presentation interface may present information to an operator of the heat chamber 100 as a user interface. In one embodiment, the presentation interface includes a display adapter (not shown) coupled to a display device (not shown), such as a cathode ray tube (CRT), a liquid crystal display (LCD), an organic light emitting diode (OLED) display, an "electronic ink" display, or the like. In some embodiments, the presentation interface includes one or more display devices. Additionally or alternatively, the presentation interface may include an audio output device (not shown), such as, but not limited to, an audio adapter, a speaker, or a printer (not shown). The controller 140 may include a user input interface coupled to the one or more processors and operable to receive input from an operator.The user input interface may include, but is not limited to, for example, a keyboard, a pointing device, a mouse, a stylus, one or more input buttons, a touch-sensitive panel such as, but not limited to, a touchpad or touchscreen, and / or an audio input interface such as, but not limited to, a microphone. A single component, such as a touchscreen, may function as both the display device and the user input interface for the presentation interface.

[0041] 1-3 , the heating chamber 100 may be configured such that localized heating within the processing environment 102 can be adjusted to control the deposition rate of the process gas 110 near a target area of ​​the wafer 104 based on a determined distance between the periphery 146 and the sidewall 152 of the wafer 104. The localized heating may be controlled by independently controlling (e.g., using the controller 140) high-intensity radiant heat lamps 128, which may be positioned above and below the processing environment 102. Additionally or alternatively, the localized heating may be controlled by selectively controlling (e.g., using the controller 140) select groups (or “radial zones”) of the heat lamps 128 to control the temperature of various regions of the semiconductor wafer 104 during processing. Independently controlling the heat lamps 128 or controlling independent radial zones of the heat lamps 128 allows for control of deposition thickness uniformity by adjusting the local temperature at the reaction site to compensate for edge roll-off effects induced by the distance between the periphery 146 and the sidewall 152, for example. The heat lamps 128 or zones thereof may be powered separately using separate power supplies or by power split control between the zones.

[0042] The heating chamber 100 may include a spot heating module 170. The spot heating module 170 includes one or more spot heaters 172. Each spot heater 172 provides localized heat within the processing chamber 102. The spot heaters 172 are utilized to provide localized heat near one or more target areas on the semiconductor wafer 104 during processing. The target area of ​​the wafer 104 for localized heat may be an area where the peripheral edge 146 is spaced from the sidewall 152, where edge roll-off is expected to occur. For example, the spot heater 172 may be utilized to provide localized heat within the processing chamber 102 to a target area of ​​the wafer 104 near the peripheral edge 146 (e.g., the area generally designated 192 in FIG. 3 ) where the wafer 104 is at a minimum distance D1 from the sidewall 152. The spot heating module 170 may thereby facilitate the reduction or elimination of edge roll-off, thereby facilitating more uniform epitaxial layer thickness and wafer flatness. Localized heating using spot heaters 172 may be controlled via controller 140 .

[0043] Each spot heater 172 is connected to an electromagnetic radiation source 174, or multiple electromagnetic radiation sources 174, for example, via a corresponding optical fiber 176. Instead of being connected to the spot heater 172 by an optical fiber, the electromagnetic radiation source 174 may be disposed directly on the spot heater 172. The electromagnetic radiation source 174 may be, for example, a pulsed electromagnetic radiation source or a continuous wave (CW) electromagnetic radiation source. Additionally or alternatively, the electromagnetic radiation source 174 may be a high-energy radiation source, such as a laser source, including, for example, crystal lasers, laser diodes and arrays, and vertical cavity surface-emitting lasers (VCSELs). A high-intensity LED light source may be used as the electromagnetic radiation source, and a collimator may be used to collimate the light emitted from the LED light source to form a light beam. The wavelength of the emitted radiation may generally be in the ultraviolet, visible, and / or infrared spectrum, from about 200 nm to about 900 nm, e.g., 810 nm, and the emitted radiation may be monochromatic, narrowband, broadband, or ultra-broadband, such as a white laser.

[0044] The electromagnetic radiation source 174 emits high-intensity electromagnetic radiation, which is transmitted to the spot heater 172 via an optical fiber 176. The spot heater 172 directs the exit end of the optical fiber 176 toward a target location within the processing environment 102, such as a target area on a wafer 104 disposed on the susceptor 120. The optical fiber 176 generates a radiation beam from the radiation emitted from the electromagnetic radiation source 174 toward the target location. The end of the optical fiber 176 can have one or more optical features, including lenses, facets, diffusive surfaces, filters, and other coatings, to direct or condition the electromagnetic radiation exiting the fiber. Alternatively, one or more optical elements can be coupled to the end of the optical fiber 176 within the spot heater 172. The spot heater 172 is reconfigurable and replaceable. The radiation beams from the electromagnetic radiation source 174 can have the same wavelength or different wavelengths. In one embodiment, the radiation beams have different wavelengths to heat regions of wafer 104 and / or different materials formed on wafer 104 .

[0045] As shown in FIG. 2 , the spot heater 172 includes a collimator 178 held by a holder 180. The collimator 178 is an optical element that collimates radiation from one of the electromagnetic radiation sources 174, for example, by using an appropriately designed lens. The collimator 178 has a first end into which radiation from the electromagnetic radiation source 174 is input, for example, by directing the output of a laser source into the opening in the first end. The collimator 178 has a second end having an opening in which a collimating optical assembly is housed. A laser or laser source may be directly attached to the collimator 178 by inserting the beam exit portion of the laser into the first end of the collimator 178 so that radiation emitted by the laser passes through the collimator 178 and exits through the second end with the collimating optical assembly, which may be a lens or a collection of lenses. The collimator 178 may alternatively be replaced by an optical fiber 176 or an electromagnetic radiation source 174, with the holder 180 holding the fiber 176 or the electromagnetic radiation source 174 directly.

[0046] The holder 180 is disposed on a stage 182. The stage 182 includes a wedge 184 and a slider 186. The stage 182 is fixed to the heat chamber 100, e.g., a base or its support. For example, the stage 182 may be fixed to a top cover of the heat chamber 100 that encloses processing equipment such as the heat lamps 128. Additionally and / or alternatively, the stage 182 may be fixed to a reflector disposed above the processing equipment (e.g., the heat lamps 128) of the heat chamber 100. The slider 186 allows linear movement of the stage 182 relative to the heat chamber 100 during processing. The slider 186 may be linearly movable using, for example, a set screw or an actuator.

[0047] The wedge 184 includes a surface that contacts the holder 180. The surface of the wedge 184 forms an angle with respect to a plane substantially parallel to the front surface 148 of the susceptor 120. The angle formed by the surface of the wedge 184 may be adjusted, for example, by an actuator disposed on the wedge 184. Adjusting this angle enables targeting of localized heating by the spot heater 172. Targeting of the spot heater 172 may be achieved by adjusting the position of the stage 182 via the slider 186. Because the angle formed by the surface of the wedge 184 and the position of the slider 186 can be adjusted by the actuator, the position of the beam spot emitted by the spot heater 172 may be adjusted during processing. The wedge 184, the slider 186, and the support of the heating chamber 100 to which the stage 182 is fixed may each be made of a material that is transparent to the radiant energy radiation emitted from the electromagnetic radiation source 174 (transmitting at least 95% of the radiant energy radiation), such as quartz. Additionally and / or alternatively, an opening may be formed through the wedge 184, slider 186, and support of the heat chamber 100 for a beam, such as a laser beam, from the collimator 178 to pass through and reach a target area on the semiconductor wafer 104. The opening is preferably large enough to accommodate movement of the wedge 184 and / or slider 186.

[0048] The spot heater 172 can be aimed by performing a manual alignment process. During the alignment process, the spot heater 172 is energized to generate the guide beam. An operator may visually observe a spot of light from the guide beam landing on the susceptor 120. The susceptor 120 may be rotated to align the area to be heated by the spot heater 172 with the guide beam. Positioning devices of the spot heater 172, such as the slider 186 and wedge 184, may then be manipulated to align the spot heater 172 with the target area to be heated. For example, the target area to be heated may be an area of ​​the wafer 104 near the periphery 146 (generally designated 192 in FIG. 3 ) where the wafer 104 is at a minimum distance D1 from the sidewall 152.

[0049] The collimator 178 may be connected to a movement device (not shown) that facilitates movement of the collimator 178 within the holder 180. The movement device may be disposed between the holder 180 and the collimator 178. The movement device may, for example, be a device that rotates the collimator 178 about its longitudinal axis. During processing, the collimator 178 may be in a first position during a first processing step, and the collimator 178 may be rotated to a second position before or during a second processing step. Rotation of the collimator 178 may, for example, change the shape and / or size of the beam spot of the radiation beam emerging from the collimator 178 onto the susceptor 120 and / or wafer 104. The movement device may continuously rotate the collimator 178 about its longitudinal axis (e.g., in a clockwise or counterclockwise rotational direction) during processing to dynamically change the shape of the beam spot. As described above, the susceptor 120 and wafer 104 may be rotated during processing. The rotation of the collimator 178 may be synchronized with the rotation of the wafer 104 to provide precise heating of one or more target regions on the wafer 104. Additionally and / or alternatively, the movement device may rotationally oscillate the collimator 178 within a predetermined angular range, such as between −60 degrees and 60 degrees. The oscillation of the collimator 178 may be synchronized with the rotation of the wafer 104. The movement device may be coupled to the fiber 176 or the electromagnetic radiation source 174 in examples in which the collimator 178 is replaced by the fiber 176 or the electromagnetic radiation source 174. The movement device may rotate the fiber 176 or the electromagnetic radiation source 174 as described above for the collimator 178.

[0050] The movement device for the collimator 178 may be a controlled movement device that generates a periodic movement, such as vibration, circular movement, or linear movement. The movement generated by the movement device is transmitted to the collimator 178, or alternatively, to the fiber 176 or the electromagnetic radiation source 174. When the movement device moves the collimator 178, the collimator 178 may move the beam spot. The movement of the beam spot preferably irradiates an exposure area on the wafer 104 that is larger than the area of ​​the beam spot. Additionally and / or alternatively, the collimator 178 may irradiate overlapping areas on the wafer 104 to approximate illumination by a larger beam spot than the beam spot generated by the electromagnetic radiation source 174. When the collimator 178 moves, the electromagnetic radiation source 174 generates a continuous electromagnetic radiation beam that irradiates an exposure area on the wafer 104 that is larger than the area of ​​the beam spot as the electromagnetic radiation beam passes through the moving collimator 178. The large beam spot defines an annular heating zone as the wafer 104 rotates during processing.

[0051] The electromagnetic radiation source 174 may be pulsed through the moving collimator 178 to form a large beam spot on the wafer 104 as the electromagnetic radiation beam passes through the moving collimator 178. The large beam spot heats multiple discrete areas on the wafer 104 as the wafer 104 rotates during processing. The pulsing of the electromagnetic radiation beam may be synchronized with the rotation of the wafer 104 and / or the movement of the beam spot. For example, the pulsing of the beam may be set to a frequency related to the oscillation frequency of the collimator 178. The related frequency may deliver pulses of radiation to overlapping areas of the wafer 104 such that an exposure area of ​​the wafer 104 larger than the area of ​​each pulse is exposed to the pulsed radiation. The duration of the pulses through the moving collimator 178 determines the angular sweep of the exposure area along the annular or partially annular heating zone.

[0052] The collimator 178 may move continuously or periodically, such as when pulses of the electromagnetic radiation beam pass through the collimator 178. In one example, the beam may be pulsed for a first duration while the collimator 178 is moving and for a second duration while the collimator 178 is not moving. In this example, a first exposed area of ​​the wafer 104 corresponding to the first duration is larger than the area of ​​the beam, and a second exposed area corresponding to the second duration has dimensions substantially the same as the dimensions of the beam.

[0053] The example methods described herein may include adjusting localized heating of the wafer 104 by adjusting the shape and / or size of a beam spot emitted by a heating radiation spot heater 172. The spot heater 172 is configured to dynamically control the shape and / or size of the beam spot without modifying the optics of the system.

[0054] The beam spot may also be formed by multiple (e.g., two) spot heaters 172 positioned and oriented such that the beam spots generated by each spot heater 172 overlap. The cooperating spot heaters 172 may include electromagnetic radiation sources 174 that generate radiation beams of the same wavelength or different wavelengths. For example, two cooperating spot heaters 172 may include a blue laser and a green laser, respectively, and the beam spot generated by the overlapping beam spots includes a blue portion and a green portion.

[0055] The beam spot may be formed by moving the collimator 178 and / or by actuating, e.g., vibrating, the slider 186. The beam spot may also be formed by actuating, e.g., moving, the angle that the surface of the wedge 184 makes with a plane substantially parallel to the front surface 148 of the susceptor 120. By moving the angle of the collimator 178, the slider 186, and / or the surface of the wedge 184, a racetrack-shaped beam spot may preferably be formed. The pair of wedges 184 of the cooperating spot heater 172 may be precisely machined at an offset angle to achieve a desired beam spot shape.

[0056] The beam spots generated by one or more spot heaters 172 may have different orientations relative to the movement of the wafer 104 during processing. For example, the beam spots may have an elliptical shape, and the major axis of the elliptical beam spot may be oriented substantially perpendicular to the movement direction (e.g., rotation direction) of the wafer 104. When the major axis of the beam spot is substantially perpendicular to the movement direction of the wafer 104, the width of the beam spot (i.e., the effective length of the major axis of the beam spot) can be adjusted without changing the optics of the spot heater 172. For example, the width of the beam spot may be changed by rotating the collimator 178. Rotating the collimator 178 rotates the orientation of the beam spot so that the major axis of the elliptical beam spot is no longer substantially perpendicular to the movement direction of the wafer 104, thereby narrowing the beam spot width. This technique also works for linear beam spots.

[0057] The heating chamber 100 may also include one or more sensors 188, such as pyrometers, located on a support (e.g., a top cover or reflector) of the chamber 100 to which the one or more spot heaters 172 are fixed. Each spot heater 172 may also include a sensor 188. Both the collimator 178 and the sensor 188 may be located on a single stage 182. The one or more sensors 188 may be used (e.g., by the controller 140) to adjust power to the spot heaters 172. For example, the controller 140 may receive temperature data from the sensor 188 and may increase or decrease power to the spot heaters 172 based on the temperature data. In such a system, the combination of the sensor 188 and the spot heater 172 can be used in closed-loop or open-loop control to adjust the spot heaters 172 based on readings from the sensor 188.

[0058] In an exemplary method, localized heating within the processing environment 102 may be adjusted (e.g., using the controller 140) based on the determined distance between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120 to control deposition rates in different regions of the wafer 104 near the periphery 146. This may enhance the uniformity of the thickness and flatness of the wafer 104 after epitaxy. For example, the controller 140 may adjust the localized heating to increase the amount of deposited material on a region of the wafer 104 near the periphery 146 where the wafer 104 is at a minimum distance D1 from the sidewall 152 (e.g., region 192 in FIG. 3 ). This may be achieved by controlling the high-intensity radiant heat lamps 128 and / or one or more spot heaters 172 of the spot heating module 170 to selectively increase localized heating within the processing environment 102 near the peripheral region of the wafer 104 located at the minimum distance D1 from the sidewall 152. Additionally or alternatively, the controller 140 may adjust the localized heating to reduce the amount of deposited material on a region of the wafer 104 near the periphery 146 where the wafer 104 is at a maximum distance D2 from the sidewall 152 (e.g., region 194 in FIG. 3 ). This may be achieved by controlling the high-intensity radiant heat lamps 128 and / or one or more spot heaters 172 of the spot heating module 170 to selectively reduce localized heating within the processing environment 102 near the peripheral region of the wafer 104 located at a maximum distance D2 from the sidewall 152. As described above, the susceptor 120 and wafer 104 may be rotated within the processing environment 102. The controller 140 may control the adjustment of the localized heating to be synchronized with the rotation of the susceptor 120 and wafer 104.

[0059] 3, the heating chamber 100 may also be configured such that the flow rates of the process gases 110 flowing within the processing environment 102 and the flow interactions between the process gases 110 are adjusted (e.g., via the controller 140) to control the deposition rate of the process gases 110 near the target area of ​​the wafer 104 based on the determined distance between the periphery 146 and the sidewall 152 of the wafer 104. The flow interactions between the process gases 110 are facilitated by a first gas injection port 106a and a second gas injection port 106b. The gas injection ports 106a and 106b may also be referred to as gas inlet ports 106a and 106b. The first gas injection port 106a delivers a first process gas 110a into the processing environment 102 in a first gas direction, and the second gas injection port 106b delivers a second process gas 110b into the processing environment 102 in a second gas direction intersecting the first gas direction. The crossover between the first process gas 110a and the second process gas 110b creates a cross-flow interaction of the process gases within the processing environment 102, preferably over the front surface 142 of the wafer 104. The controlled flow interaction between the process gases within the processing environment 102 can provide benefits such as controlling the thickness and / or composition uniformity of the deposited epitaxial layer.

[0060] As shown in FIG. 3 , the susceptor 120 defines an X-axis and a Y-axis. The X-axis and the Y-axis are substantially perpendicular to each other and intersect at a center C of the susceptor 120. The X-axis and the Y-axis extend across the front surface 148 and the recess 150 of the susceptor 120, respectively. The first gas inlet port 106a and the gas exhaust port 108 are disposed on opposite sides of the susceptor 120 and are aligned substantially along the X-axis. The second gas inlet port 106b is disposed between the first gas inlet port 106a and the gas exhaust port 108 to supply a second process gas 110b at an angle relative to the first process gas 110a supplied by the first gas inlet port 106a. The second gas inlet port 106b and the first gas inlet port 106a are separated by an azimuthal angle 190. The azimuthal angle 190 may be any angle that facilitates the heating chamber 100 functioning as described herein. For example, the azimuth angle 190 may be between 0 and 145 degrees, measured on either side of the susceptor 120. In the example shown in Figure 3, the azimuth angle 190 is approximately 90 degrees. The location of the second gas inlet port 106b in Figure 3 is an example, and the second gas inlet port 106b may include other locations relative to the first gas inlet port 106a.

[0061] The first gas inlet port 106a supplies a first process gas 110a onto the front surface 142 of the wafer 104 in a first direction generally indicated by the arrow 110a. The term "process gas" refers to both a single gas and a mixture of gases. For example, the process gas 110a may include a deposition precursor gas (e.g., trichlorosilane, TCS) combined with a carrier gas (e.g., H) and / or an etchant gas (e.g., HCl). The term "direction" refers to the direction in which the process gas exits the inlet port. Upon exiting each inlet port, at least a portion of the process gas may deviate from the exit direction within the processing environment 102 to cover the front surface 142 of the wafer 104. In the exemplary chamber 100, the first direction of the first process gas 110a is substantially parallel to the front surface 142 of the wafer 104 and generally directed toward the opposing gas exhaust port 108.

[0062] The first gas inlet port 106a may include a single port defining the gas inlet 103 through which the first process gas is supplied, as shown schematically in FIG. 3, or may include multiple secondary inlets (not shown) that collectively define the gas inlet 103. For example, the first gas inlet port 106a may include up to five inlets, although more or fewer secondary inlets may be provided (e.g., one or more). Each secondary inlet may supply a first process gas 110a, which may be, for example, a mixture of multiple process gases. Additionally and / or alternatively, one or more secondary inlets may supply one or more process gases 110a that are different from at least one other secondary inlet. The process gases supplied by the first gas inlet port 106a may be substantially uniformly mixed after exiting the first gas inlet port 106a to form the first process gas 110a. For example, the process gases are generally not mixed after exiting the first gas inlet port 106a, and the first process gas 110a may have an intentionally non-uniform composition. The flow rate, process gas composition, etc. at the first gas inlet port 106a, or each of its secondary inlets, may be independently controlled. In some embodiments, some of the secondary inlets may be unused during processing or pulsed to achieve a desired flow interaction with the second process gas 110b, for example, provided by the second inlet port 106b. Furthermore, in embodiments in which the first gas inlet port 106a comprises a single port, the single port may be pulsed or modulated (e.g., by restricting flow therethrough) to achieve a desired flow interaction with the second process gas 110b.

[0063] The second gas inlet port 106b may be identical or substantially similar in design to the first gas inlet port 106a. As described above for the first gas inlet port 106a, the second gas inlet port 106b may include a single port, as shown schematically in FIG. 3. Additionally and / or alternatively, the second gas inlet port 106b may include multiple secondary inlets, as described above for the first gas inlet port 106a. Each secondary inlet may supply the second process gas 110b, or one or more process gases different from at least one other secondary inlet. The process gases may mix substantially uniformly after exiting the second gas inlet port 106b to form the second process gas 110b. The process gases generally do not mix after exiting the second gas inlet port 106b, and the second process gas 110b may have an intentionally non-uniform composition. The flow rates, process gas compositions, etc. at the second gas inlet port 106b, or each of its secondary inlets, may be independently controlled. The second gas inlet port 106b, or some or all of its secondary inlets, may be unused or pulsed during processing, for example, to achieve a desired flow interaction with the first process gas 100a supplied by the first gas inlet port 106a.

[0064] The second gas inlet port 106b supplies the second process gas 110b in a second direction that intersects the first direction. Preferably, the second direction intersects the first direction such that cross-flow interaction between the first process gas 110a and the second process gas 110b occurs on the front surface 142 of the wafer 104. The relationship between the first direction of the first process gas 110a and the second direction of the second process gas 110b can be defined at least in part by an azimuthal angle 190. The azimuthal angle 190 is measured between the outlet of the first gas inlet port 106a and the outlet of the second gas inlet port 106b about the central axis of the susceptor 120 (i.e., an axis that extends substantially perpendicular to the X-axis and Y-axis and intersects each at center C). The azimuthal angle 190 may be up to approximately 145 degrees, i.e., between approximately 0 degrees and approximately 145 degrees. For example, the azimuthal angle 190 may be less than 90 degrees, such that the second gas inlet port 106b is located closer to the first gas inlet port 106a than to the gas exhaust port 108. In another example, the azimuthal angle 190 may be greater than 90 degrees, such that the second gas inlet port 106b is located closer to the gas exhaust port 108 than to the first gas inlet port 106a. In another example, and as shown in FIG. 3 , the azimuthal angle 190 is approximately 90 degrees. The azimuthal angle 190 may be selected to provide a desired amount of cross-flow interaction between the first process gas 110a and the second process gas 110b.

[0065] Either or both of the first and second directions of the first and second process gases 110a and 110b, respectively, may be substantially parallel to the front surface 142 of the wafer 104 or may be angled relative to the front surface 142 of the wafer 104 (i.e., angled relative to the XY plane defined by the X and Y axes). For example, the first gas inlet port 106a may have one or more secondary inlets oriented such that the first direction is angled relative to the XY plane, and / or the second gas inlet port 106b may have a similar configuration with one or more secondary inlets oriented such that the second direction is angled relative to the XY plane.

[0066] In one example, the azimuthal angle 190 is 0 degrees. In such an example, the first gas inlet port 106a and the second gas inlet port 106b may be vertically aligned, e.g., stacked on top of one another or integrated into a single unit. In such an embodiment, the first and second directions are different (even though the azimuthal angle 190 between them is 0 degrees) due to the angled orientation of the second direction relative to the XY plane and the parallel orientation of the first direction and the parallel orientation of the second direction relative to the XY plane. Therefore, even when the azimuthal angle 190 is 0 degrees, flow interaction may occur between the first process gas 110a and the second process gas 110b.

[0067] The azimuthal angle 190 may define the difference between the first and second directions of the first and second process gases 110a and 110b. For example, when the first and second directions are both parallel to the XY plane and the first and second gas inlet ports 106a and 106b are oriented such that the first and second directions, respectively, are aligned across the diameter of the susceptor 120 (and / or wafer 104), the azimuthal angle 190 generally defines a flow interaction angle. In these examples, the azimuthal angle 190 is preferably non-zero so that the first and second directions differ and flow interaction can be achieved.

[0068] The first gas inlet port 106a and the second gas inlet port 106b may be located at different heights to further promote flow interaction between the first process gas 110a and the second process gas 110b. For example, the first gas inlet port 106a may be located at a first height, and the second inlet port 106b may be located at a second height above the front surface 142 of the wafer 104. The first and second heights may be adjustable, e.g., each height may be set before processing the wafer 104 in the chamber 100, or each inlet port 106a, 106b may be mounted on a movable platform (not shown), or the susceptor 120 may be moved along its central axis to adjust the first and second heights (e.g., if the susceptor 120 is vertically movable to position the wafer 104 at a different processing plane). The second height of the second gas inlet port 106a may be higher, lower, or the same as the first height of the first gas inlet port 106a. In such embodiments, the second direction of the second process gas 110b may be parallel to or at an angle to the XY plane.

[0069] In the example shown in FIG. 3 , the first gas inlet port 106a is oriented such that the first direction of the first process gas 110a is substantially aligned with the diameter of the susceptor 120 and / or the wafer 104. For example, the first direction is substantially aligned with the X-axis. The second gas inlet port 106b is angled with respect to the central axis of the susceptor 120 (i.e., axes that extend substantially perpendicular to the X-axis and Y-axis and intersect each other at center C). As such, the second direction is not aligned with the diameter of the susceptor 120 and / or the wafer 104. In other examples, the second gas inlet port 106b may be oriented such that the second direction is aligned with the diameter of the susceptor 120 and / or the wafer 104 (e.g., the second direction may be substantially aligned with the Y-axis). In these examples, the first gas inlet port 106a may be oriented as described above, or the first gas inlet port 106a may be angled with respect to the central axis of the susceptor 120.

[0070] The second gas inlet port 106b may be angled relative to the central axis such that the second direction faces toward a region of the wafer 104 near the periphery 146 where the wafer 104 is spaced a minimum distance D1 from the sidewall 152, generally indicated at 192 in FIG. 3 . Region 192 may be referred to herein as a first peripheral region 192. The orientation of the first gas inlet port 106a and the second gas inlet port 106b may increase cross-flow interaction between the first process gas 110a and the second process gas 110b near the first peripheral region 192 of the wafer 104 where less epitaxial material may be deposited due to the minimum distance D1 of the periphery 146 from the sidewall 152. Increasing the cross-flow interaction between the first process gas 110a and the second process gas 110b in the first peripheral region 192 may be preferred when both the process gas 110a and the process gas 110b include a deposition precursor gas (e.g., trichlorosilane, TCS) such that the deposition rate of the first process gas 110a and the second process gas 110b near the first peripheral region 192 of the wafer 104 may be increased. Additionally or alternatively, the cross-flow interaction between the first process gas 110a and the second process gas 110b, which together include a deposition precursor gas, may be decreased near a region of the wafer 104 near the periphery 146 where the wafer 104 is spaced a maximum distance D2 from the sidewall 152, generally designated 194 in FIG. 3 . Region 194 may also be referred to herein as the second peripheral region 194. Because the second direction of the second process gas 110b does not point toward the second peripheral region 194, reduced cross-flow interaction may be reduced in the second peripheral region 194. As a result, the deposition rate of the first process gas 110a and the second process gas 110b near the second peripheral region 194 may be reduced. This may be advantageous because the second peripheral region 194, which defines the maximum distance D2, is subject to a relatively large amount of epitaxial material.

[0071] In other embodiments, the first gas inlet port 106a and the second gas inlet port 106b may be oriented to increase cross-flow interaction between the first process gas 110a and the second process gas 110b near a second peripheral region 194 of the wafer 104 where more epitaxial material may be deposited due to the maximum distance D2 of the edge 146 from the sidewall 152. Increasing cross-flow interaction between the first process gas 110a and the second process gas 110b in the second peripheral region 194 may be preferable when at least one of the process gases 110a, 110b includes an etchant gas (e.g., hydrogen chloride, HCl), which may reduce the deposition rate of the first process gas 110a and the second process gas 110b near the second peripheral region 194 of the wafer 104.

[0072] The angle of the second gas inlet port 106b for directing the second direction of the second process gas 110b can depend on the azimuth angle 190. For example, the second gas inlet port 106b may be positioned such that the azimuth angle 190 is approximately 90 degrees, and in such an example, the second gas inlet port 106b may be angled relative to the central axis of the susceptor 120 such that the second direction forms an angle with the central axis of the susceptor 120 of between 15 and 45 degrees, e.g., between 20 and 40 degrees, or between 25 and 35 degrees, e.g., between 30 degrees. In other examples where the azimuth angle 190 is greater than or less than 90 degrees, other angles of the second gas inlet port 106b may be used to target the same peripheral region of the wafer 104. Further, in some examples, the second gas inlet port 106b may be substantially aligned with the diameter of the susceptor 120 and / or the wafer 104, and / or the first gas inlet port 106a may be angled relative to the central axis of the susceptor 120, as described above.

[0073] As described above, the wafer 104 preferably rotates during processing. As a result, the orientation of the first gas inlet port 106a and the second gas inlet port 106b to control the flow interaction of the first process gas 110a and the second process gas 110b near the target area of ​​the wafer 104 (e.g., to increase the flow interaction near the first peripheral region 192 and / or decrease the flow interaction near the second peripheral region 194) may be sufficient for only a portion of the process. As the wafer rotates, the second peripheral region 194 approaches a region where the flow interaction is intentionally increased, and the first peripheral region 192 approaches a region where the flow interaction is intentionally decreased. In general, it is difficult to change the angle and / or orientation of the first gas inlet port 106a and the second gas inlet port 106b during processing. Therefore, the flow rates of the process gases 110a, 110b may be adjusted (e.g., via the controller 140) to compensate for the rotation of the wafer 104 during processing.

[0074] The flow rates of the process gases 110a, 110b are preferably adjusted such that the deposition rates of the first process gas 110a and the second process gas 110b increase near a first peripheral region 192 of the wafer 104 and decrease near a second peripheral region 194. Furthermore, adjustment of the flow rates of the process gases 110a, 110b is preferably synchronized with the rotation of the wafer 104. For example, as the wafer rotates, the flow rates of the process gases 110a, 110b may increase as the first peripheral region 192 approaches the region targeted by the angle and orientation of the first and second gas inlet ports 106a, 106b, and the flow rates of the process gases 110a, 110b may decrease as the second peripheral region 194 approaches the region targeted by the angle and orientation of the first and second gas inlet ports 106a, 106b. Adjusting the flow rates of the process gases 110a, 110b may additionally and / or alternatively include adjusting the flow rates of specific process gases comprising process gas 110a and / or process gas 110b. For example, adjusting the flow rates of the process gases 110a, 110b may include increasing the flow rate of a deposition precursor gas (e.g., trichlorosilane, TCS) included in the process gases 110a, 110b as the first peripheral region 192 approaches the region targeted by the angle and orientation of the first and second gas inlet ports 106a, 106b. Similarly, adjusting the flow rates of the process gases 110a, 110b may include increasing the flow rate of an etchant gas (e.g., hydrogen chloride) included in the process gases 110a, 110b as the second peripheral region 194 approaches the region targeted by the angle and orientation of the first and second gas inlet ports 106a, 106b. In this manner, the first peripheral region 192 is preferably targeted with a greater amount of process gas that deposits epitaxial material on the front surface 142 of the wafer 104, and the second peripheral region is preferably targeted with a greater amount of etchant gas that smooths and / or removes the epitaxial material deposited on the front surface 142 of the wafer 104.

[0075] Referring now to FIG. 4 , a process flow diagram of an exemplary method 200 for processing a semiconductor wafer is shown. The method 200 includes placing 202 a semiconductor wafer 104 in a recess 150 of a susceptor 120. The susceptor 120 supports the wafer 104 within the processing environment 102 of the heater chamber 100. The recess 150 is defined by a downwardly extending sidewall 152 on the front surface 148 of the susceptor 120. The recess 150 is sized and shaped to receive the wafer 104. Preferably, the recess is sized and shaped such that the peripheral edge 146 of the wafer 104 is spaced from the sidewall 152. Due to wafer placement tolerances, wafer movement during placement, thermal expansion, and / or other factors, the wafer 104 may not be perfectly centered such that variations in the distance between the peripheral edge 146 and the sidewall 152 exist along the circumferential extent of the wafer 104.

[0076] The method 200 also includes determining 204 a distance of the periphery 146 of the wafer 104 from the sidewall 152. Preferably, determining 204 includes determining a minimum distance D1 of the periphery 146 from the sidewall 152 and / or determining a maximum distance D2 of the periphery 146 from the sidewall 152. The distance of the periphery 146 of the wafer 104 from the sidewall 152 may be determined, for example, by measurements collected by the optical sensor 158 (e.g., a camera) as described above. In some examples, the method 200 may include determining a peripheral region of the wafer 104 (e.g., region 192) that is located the minimum distance D1 from the sidewall 152. Additionally or alternatively, the method 200 may include determining a peripheral region of the wafer 104 (e.g., region 194) that is located the maximum distance D2 from the sidewall 152.

[0077] The method 200 also includes supplying 206 a first process gas 110a into the heat chamber 100 in a first gas direction at a first gas flow rate and a second process gas 110b into the heat chamber 100 in a second gas direction intersecting the first gas direction at a second gas flow rate. The first process gas 110a may be supplied through a first gas injection port 106a, and the second process gas 110b may be supplied through a second gas injection port 106b. The first gas injection port 106a and the second gas injection port 106b may be angled or oriented such that the first process gas 110a and the second process gas 110b intersect to create a cross-flow interaction within the processing environment 102, as described above.

[0078] The first process gas 110a may include one or more process gases. For example, the process gas may include a deposition gas and / or an etchant gas, such as for a selective epitaxial growth process. The first process gas 110a may include one or more deposition precursor gases and, optionally, one or more dopant precursor gases, etchant gases, or carrier gases. The deposition precursor gas may include a silicon precursor, such as at least one of silane (SiH), disilane (SiH), dichlorosilane (HSiCl), and trichlorosilane (HClSi). The dopant precursor gas may include at least one of germane (GeH), phosphine (PH), diborane (BH), arsine (AsH), or methylsilane (HCSiH). The etchant gas may include at least one of methane (CH), a chloride-containing gas such as hydrogen chloride (HCl) and / or chlorine (Cl), or hydrogen fluoride (HF). The carrier gas may include at least one of nitrogen (N), argon (Ar), helium (He), or hydrogen (H).

[0079] To deposit a layer comprising silicon and germanium, the first process gas 110a may include dichlorosilane, germane, diborane, and hydrogen. To deposit a layer of silicon, the first process gas 110a may include at least one of silane, disilane, dichlorosilane, or trichlorosilane along with hydrogen chloride and hydrogen. To deposit doped silicon, the first process gas 110a may include the above gases and may further include at least one of phosphine, diborane, or arsine. To deposit a layer comprising silicon and carbon, the first process gas 110a may include disilane, methylsilane, germane, phosphine, and at least one of hydrogen chloride or chlorine in an environment including at least one of nitrogen or hydrogen.

[0080] The second process gas 110b may be the same as or different from the first process gas 110a. The second process gas 110b may include a combination of any or all of the gases described above for the first process gas (e.g., a combination of a deposition precursor gas, an etchant gas, a dopant precursor gas, and a carrier gas). During a selective epitaxial growth process, for example, the second process gas 110b may include an etchant gas, a deposition precursor gas, or a combination thereof. The second process gas 110b may be flowed alternately, periodically, partially simultaneously, or simultaneously with the first process gas 110a.

[0081] The second process gas 110b may be different from the first process gas 110a, for example, to improve compositional uniformity in the deposited layer. The second process gas 110b may be different from the first process gas 110a, for example, by providing a catalytic gas that catalyzes the first process gas 110a. For example, such catalysis may improve the compositional uniformity and / or thickness of the layer deposited on the wafer 104. The second process gas 110b may include a catalyst and other gases, such as silane and / or germane, as listed above. An example of a catalyst may include germane.

[0082] The method 200 also includes supplying 208 heat to the heating chamber 100 to induce deposition of the first process gas 110a and the second process gas 110b on the surface (e.g., front surface 142) of the wafer 104. The heat may be supplied by radiant heat lamps 128 and / or spot heaters 170, as described above.

[0083] The method 200 also includes adjusting 210 at least one of a first gas flow rate of the first process gas 110a, a second gas flow rate of the second process gas 110b, and heat supplied to the heating chamber 100 to control a deposition rate of the first process gas 110a and the second process gas 110b near the periphery 146 of the wafer 104 based on the determined distance of the periphery 146 of the wafer 104 from the sidewall 152. Preferably, adjusting at least one of the first gas flow rate, the second gas flow rate, and the heat supplied to the heating chamber 100 selectively increases or decreases the deposition rate of the first process gas 110a and the second process gas 110b near the periphery 146 of the wafer 104 based on the determined distance of the periphery 146 of the wafer 104 from the sidewall 152.

[0084] For example, the method 200 may include adjusting 210 the heat supplied to the heat chamber 100 to increase localized heating within the heat chamber 100 near a first peripheral region 192 of the wafer 104 that defines a minimum distance D1 from the sidewall 152, and / or adjusting the heat supplied to the heat chamber 100 to decrease localized heating within the heat chamber 100 near a second peripheral region 194 of the wafer 104 that defines a maximum distance D2 from the sidewall. Preferably, adjusting 210 the heat supplied to the heat chamber 100 increases the deposition rate of the first process gas 110a and the second process gas 110b near the first peripheral region 192 and / or decreases the deposition rate of the first process gas 110a and the second process gas 110b near the second peripheral region 194. Regulating 210 the heat supplied to the heat chamber 100 may include independently controlling the heat lamps 128 or radial zones thereof, or controlling one or more of the spot heaters 172 to generate radiant heat at a target region (e.g., peripheral region 192) on the wafer 104. The controller 140 may be used to regulate 210 the heat supplied to the heat chamber 100 by controlling the heat lamps 128 and / or the spot heaters 172 based on the distance determined in 204 from the sidewall 152 of the peripheral edge 146 of the wafer 104. In some examples, the method 200 includes rotating the susceptor 120 and wafer 104 and synchronizing adjusting 210 the heat supplied to the heat chamber 100 with the rotation of the susceptor 120 and wafer 104.

[0085] 5 and 6 are provided to further illustrate adjusting 210 the heat supplied to the heat chamber 100 based on the distance determined at 204 between the periphery 146 of the wafer 104 and the sidewall 152. FIG. 5 is a graph illustrating adjusting 210 the local heating by the spot heater 172 in the heat chamber 100 based on the distance determined at 204 between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120. As shown in FIG. 5, localized heating in the heat chamber 100 is increased in regions of the wafer 104 near where the distance between the periphery 146 of the wafer and the sidewall 152 of the susceptor 120 is smallest. FIG. 6 is a graph conceptually illustrating the normalized edge roll-off of an epitaxial wafer that may be processed with and without adjusting the local heating at 210 shown in FIG. 5. As shown, compared to the conventional process (labeled EOR(POR) in FIG. 6 ), the method including adjusting 210 the localized heating based on the distance determined in 204 (illustrated in FIG. 5 and labeled EOR(New) in FIG. 6 ) can produce epitaxial wafers with better normalized edge roll-off, which can contribute to improved thickness and flatness uniformity of the epitaxial wafer.

[0086] 4 , the method 200 may additionally and / or alternatively include adjusting 210 a first gas flow rate and / or a second gas flow rate to achieve a desired flow interaction (e.g., cross-flow interaction) between the first process gas 110 a and the second process gas 110 b near the peripheral region of the wafer 104 based on the distance determined in 204 between the periphery 146 and the sidewall 152. The controller 140 may be used to adjust 210 the first gas flow rate and / or the second gas flow rate. For example, the first gas flow rate and / or the second gas flow rate may be adjusted in 210 to increase flow interaction near the first peripheral region 192 of the wafer 104 and / or to decrease flow interaction near the second peripheral region 194 of the wafer 104 when the first process gas 110 a and the second process gas 110 b comprise deposition precursor gases. Additionally or alternatively, if the first process gas 110a and / or the second process gas 110b include an etchant gas, the first gas flow rate and / or the second gas flow rate may be adjusted at 210 to increase flow interaction near the second peripheral region 194 of the wafer 104.

[0087] As described above, the method 200 may also include rotating the susceptor 120 and the wafer 104 and adjusting 210 the first gas flow rate and / or the second gas flow rate in synchronization with the wafer rotation speed to control the deposition rate of the first and second process gases near the target peripheral region of the wafer 104 based on the distance determined in 204. For example, as the wafer 104 rotates, the first gas flow rate and / or the second gas flow rate may be adjusted in 210 to increase as the first peripheral region 192 approaches the region targeted by the angle and orientation of the first gas inlet port 106 a and the second gas inlet port 106 b, and / or the first gas flow rate and / or the second gas flow rate may be adjusted in 201 to decrease as the second peripheral region 194 approaches the region targeted by the angle and orientation of the first gas inlet port 106 a and the second gas inlet port 106 b. As described above, adjusting 210 the first and / or second gas flow rates may additionally and / or alternatively include adjusting 210 the flow rates of particular process gases (e.g., deposition precursor gases and / or etchant gases) comprising process gas 110a and / or process gas 110b. The flow rates of particular process gases may be adjusted 210 based on the target peripheral region of wafer 104 that receives the majority of flow interaction between first process gas 110a and second process gas 110b at a particular stage of the deposition process, which may change as wafer 104 rotates during processing. Thus, for example, when first peripheral region 192 of wafer 104 receives the majority of flow interaction between first process gas 110a and second process gas 110b, the first and / or second gas flow rates may be adjusted to increase the flow rate of deposition precursor gas (e.g., trichlorosilane, TCS). For example, when the second peripheral region 194 of the wafer 104 receives the majority of the flow interaction between the first process gas 110a and the second process gas 110b, the first gas flow rate and / or the second gas flow rate may be adjusted to increase the flow rate of the etchant gas (e.g., hydrogen chloride, HCl).

[0088] 7-10 are provided to further illustrate adjusting 210 the first and / or second gas flow rates based on the distance determined at 204 between the periphery 146 of the wafer 104 and the sidewall 152. FIG. 7 is a graph illustrating adjusting 210 the flow rate of trichlorosilane (TCS) process gas within the heater chamber 100 based on the distance determined at 204 between the periphery 146 of the wafer 104 and the sidewall 152 of the susceptor 120. As shown in FIG. 7, the flow rate of the TCS process gas is increased near the region of the wafer 104 where the distance between the periphery 146 of the wafer and the sidewall 152 of the susceptor 120 is smallest. FIG. 8 is a graph conceptually illustrating the normalized edge roll-off of an epitaxial wafer that may be processed with and without adjusting the flow rate of the TCS process gas at 210 as shown in FIG. 7. As shown, compared to the conventional process (labeled EOR(POR) in FIG. 8), the method including adjusting 210 the flow rate of the TCS process gas based on the distance determined in 204 (illustrated in FIG. 7 and labeled EOR(New) in FIG. 8) can produce epitaxial wafers with better normalized edge roll-off, which can contribute to improved thickness and flatness uniformity of the epitaxial wafers.

[0089] 9 is a graph illustrating adjusting 210 the flow rate of hydrogen chloride (HCl) process gas (or etchant gas) within the heater chamber 100 based on the distance determined at 204 between the periphery 146 of the wafer 104 and the sidewall 152. As shown in FIG. 9, the flow rate of the HCl etchant gas is increased in a region of the wafer 104 near the area where the distance between the periphery 146 of the wafer and the sidewall 152 of the susceptor 120 is greatest. The flow rate of the HCl etchant gas is decreased in a region of the wafer 104 near the area where the distance between the periphery 146 of the wafer and the sidewall 152 of the susceptor 120 is smallest. FIG. 10 is a graph conceptually illustrating the normalized edge roll-off of an epitaxial wafer that may be processed with and without adjusting the flow rate of the HCl etchant gas at 210 as shown in FIG. 9. As shown, compared to the conventional process (labeled EOR(POR) in FIG. 10 ), the method including adjusting 210 the flow rate of the HCl etchant gas based on the distance determined in 204 (illustrated in FIG. 9 and labeled EOR(New) in FIG. 10 ) can produce epitaxial wafers with better normalized edge roll-off, which can contribute to improved thickness uniformity and flatness of the epitaxial wafers.

[0090] Exemplary systems and methods for depositing a layer (e.g., an epitaxial layer) on a semiconductor wafer in a heated chamber are described above, allowing for control of processing conditions during deposition based on the wafer's position within the heated chamber. In particular, the semiconductor wafer is supported on a susceptor within the heated chamber, and the described systems and methods facilitate control of deposition behavior that may be affected by the off-center position of the semiconductor wafer within the susceptor recess. It has been discovered that the distance between the wafer's periphery and the susceptor recess sidewalls can adversely affect the thickness uniformity of the deposited layer and, therefore, the flatness of the processed wafer. In particular, a larger distance between the wafer's periphery and the recess sidewalls can cause an uptick in the deposited layer thickness near the wafer's periphery, while a smaller distance between the wafer's periphery and the sidewalls can cause a downtick in the deposited layer thickness near the wafer's periphery. Thus, if a semiconductor wafer is off-center within a recess and the distance between the wafer periphery and the recess sidewall varies circumferentially along the wafer, the deposited layer may have upticks and downticks near the wafer periphery, resulting in non-uniform thickness and reduced flatness of the processed wafer. Centering of the wafer within the recess is limited by wafer placement tolerances, wafer movement during placement, thermal expansion, and / or other constraints and may not be adequately controlled to mitigate or prevent such deposition behavior near the wafer periphery.

[0091] Thus, in the above-described embodiment, the distance between the wafer periphery and the recess sidewall of the susceptor is determined, and processing conditions are adjusted based on this determination. For example, the flow rate of process gas introduced into the processing environment of the heating chamber and / or the heat supplied to the processing environment may be adjusted to selectively control the deposition rate at specific wafer peripheral regions depending on the distance between the periphery and the recess sidewall. For wafer peripheral regions located at relatively small distances from the recess sidewall, processing conditions (e.g., process gas flow rate and / or heat intensity) may be adjusted to selectively increase the deposition rate at these regions. For wafer peripheral regions located at relatively large distances from the recess sidewall, processing conditions (e.g., process gas flow rate and / or heat intensity) may be adjusted to selectively decrease the deposition rate at these regions. For example, localized heating control using one or more spot heaters and / or cross-flow interactions between process gases within the processing environment may be utilized to provide greater control over selectively increasing and / or decreasing the deposition rate at specific wafer peripheral regions based on the distance from the recess sidewall. In this manner, epitaxial wafers with improved edge roll-off and improved uniformity of epitaxial wafer thickness and flatness may be produced at higher throughput and in a cost-effective manner.

[0092] As used herein, the terms "about," "substantially," "essentially," and "approximately," when used in conjunction with a range of dimensions, densities, temperatures, or other physical or chemical properties or characteristics, are meant to encompass variations that may exist at the upper and / or lower limits of the range of the property or characteristic, including variations that result, for example, from rounding, measurement methods, or other statistical variations.

[0093] When introducing elements of the disclosure or embodiment(s) thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0094] Because various changes may be made in the above-described structures and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

Claims

1. 1. A method for processing a semiconductor wafer in a heating chamber including a susceptor for supporting the semiconductor wafer, the susceptor having a front surface and a recess defined in the front surface by downwardly extending sidewalls; The method comprises: placing a semiconductor wafer in the recess of the susceptor; determining a distance of the wafer's periphery from the sidewall; supplying a first process gas into the heating chamber at a first gas flow rate in a first gas direction, and supplying a second process gas into the heating chamber at a second gas flow rate in a second gas direction intersecting the first gas direction; providing heat to the heating chamber to induce deposition of the first process gas and the second process gas on the surface of the wafer; adjusting at least one of the first gas flow rate, the second gas flow rate, and the heat supplied to the heating chamber to control deposition rates of the first process gas and the second process gas near the periphery of the wafer based on the determined distance of the periphery from the sidewall of the wafer; A method comprising:

2. The method of claim 1 , further comprising determining at least one of a minimum distance of the periphery of the wafer from the sidewall and a maximum distance of the periphery of the wafer from the sidewall.

3. 3. The method of claim 2, further comprising adjusting heat supplied to the heat chamber to increase localized heating within the heat chamber near a peripheral region of the wafer that defines the minimum distance from the sidewall.

4. 3. The method of claim 2, further comprising adjusting heat supplied to the heat chamber to reduce localized heating within the heat chamber near a peripheral region of the wafer that defines the maximum distance from the sidewall.

5. 3. The method of claim 2, further comprising adjusting at least one of the first gas flow rate and the second gas flow rate to increase flow interaction between the first process gas and the second process gas near a peripheral region of the wafer that defines the minimum distance from the sidewall.

6. 3. The method of claim 2, further comprising adjusting at least one of the first gas flow rate and the second gas flow rate to reduce flow interaction between the first process gas and the second process gas near a peripheral region of the wafer that defines the maximum distance from the sidewall.

7. further comprising rotating the wafer during the supply of the first process gas and the second process gas and during the supply of the heat; 2. The method of claim 1, wherein adjusting at least one of the first gas flow rate, the second gas flow rate, and the heat supplied to the heating chamber is synchronized with a rotation speed of the wafer to control a deposition rate of the first process gas and the second process gas near the periphery of the wafer based on the determined distance of the periphery from the sidewall of the wafer.

8. The method of claim 1 , wherein the first process gas and the second process gas comprise a deposition precursor gas and an etchant gas.

9. The method of claim 8 , further comprising determining a minimum distance of the periphery of the wafer from the sidewall.

10. The method further includes adjusting at least one of the first gas flow rate and the second gas flow rate to increase the flow of the deposition precursor gas near a peripheral region of the wafer that defines the minimum distance from the sidewall.

11. 10. The method of claim 9, further comprising adjusting at least one of the first gas flow rate and the second gas flow rate to reduce a flow of the etchant gas near a peripheral region of the wafer that defines the minimum distance from the sidewall.

12. 2. The method of claim 1, wherein adjusting at least one of the first gas flow rate, the second gas flow rate, and the heat supplied to the heating chamber selectively increases the deposition rate of the first process gas and the second process gas near a peripheral region of the wafer located at a relatively large distance from the sidewall.

13. 1. A method for processing a semiconductor wafer in a heating chamber including a susceptor for supporting the semiconductor wafer, the susceptor having a front surface and a recess defined in the front surface by downwardly extending sidewalls; The method comprises: placing a semiconductor wafer in the recess of the susceptor; determining a peripheral area of ​​the wafer that is located a minimum distance from the sidewall; supplying a first process gas into the heating chamber at a first gas flow rate in a first gas direction, and supplying a second process gas into the heating chamber at a second gas flow rate in a second gas direction intersecting the first gas direction; At least one of the first gas flow rate and the second gas flow rate is adjusted to selectively increase a deposition rate of the first process gas and the second process gas near a peripheral region of the wafer located at the minimum distance from the sidewall. A method comprising:

14. 14. The method of claim 13, wherein the first process gas and the second process gas comprise a deposition precursor gas and an etchant gas.

15. 15. The method of claim 14, wherein adjusting at least one of the first gas flow rate and the second gas flow rate comprises increasing a flow rate of the deposition precursor gas near the peripheral region of the wafer located at the smallest distance from the sidewall.

16. 15. The method of claim 14, wherein adjusting at least one of the first gas flow rate and the second gas flow rate comprises decreasing a flow rate of the etchant gas near the peripheral region of the wafer located at the smallest distance from the sidewall.

17. 1. A method for processing a semiconductor wafer in a heating chamber including a susceptor for supporting the semiconductor wafer, the susceptor having a front surface and a recess defined in the front surface by downwardly extending sidewalls; The method comprises: placing a semiconductor wafer in the recess of the susceptor; determining a peripheral area of ​​the wafer that is located a minimum distance from the sidewall; supplying a process gas to the heating chamber; providing heat to the heating chamber to induce a volume of the process gas onto the surface of the wafer; adjusting the heat supplied to the heating chamber to selectively increase the deposition rate of the process gas near the peripheral region of the wafer located at the minimum distance from the sidewall; A method comprising:

18. Rotating the susceptor; Synchronizing the regulation of heat supplied to the heating chamber with the rotation of the susceptor 20. The method of claim 17, further comprising:

19. 20. The method of claim 17, wherein adjusting the heat supplied to the heat chamber comprises selectively increasing localized heating within the heat chamber near the peripheral region located at the smallest distance from the sidewall.

20. 20. The method of claim 17, wherein adjusting the heat supplied to the heating chamber comprises adjusting one or more spot heaters to selectively increase localized heating supplied by the one or more spot heaters to the peripheral region of the wafer located the smallest distance from the sidewall.

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