Multi-zone lamp control and individual lamp control in lamp heads

Abstract

A method and apparatus for processing a semiconductor substrate are described. A substrate processing apparatus is disclosed, comprising: a processing chamber; a substrate support disposed within the processing chamber; a plurality of lamps arranged in a lamp head and positioned proximate to the substrate support; a gas source for providing a purge gas in a lateral flow path across the substrate support; and a controller for differentially adjusting power provided to individual lamps of the plurality of lamps based on a direction of the flow path.

Description

Technical Field

[0001] Methods and apparatus for semiconductor processing are disclosed herein. More particularly, embodiments disclosed herein relate to methods and apparatus for controlling particle contamination in epitaxial processes. Background Art

[0002] Epitaxy is a process widely used in semiconductor processing to form very thin layers of material on a semiconductor substrate. These layers typically define some of the smallest features of a semiconductor device, and if the electrical properties of the crystalline material are desired, they can have a high-quality crystalline structure. To form these layers, a deposition precursor is provided to a processing chamber having a pedestal on which a substrate is disposed and the substrate is heated to a temperature conducive to the growth of a layer of material having the desired properties. Due to the small feature size of the semiconductor devices formed on the substrate, the amount of particles on the substrate must be kept to a minimum.

[0003] However, particles may adhere to the substrate to be processed during the period when the substrate to be processed is transferred into the processing chamber. For example, in a process in which a processing gas is provided at one side of the substrate to flow over the surface of the substrate, the gas flowing into the chamber during the transfer of the substrate to be processed may produce particles that fall on the substrate to be processed. The particles may fall off from the chamber wall and then be entrained in the gas flow. In addition, the temperature of the base may be uneven, causing the substrate to warp upon initial contact with the base. The reserved area for particles on the substrate may be larger or smaller, depending on the orientation of the warping profile of the substrate relative to the direction of the gas flow. If the substrate adopts a warped shape presenting a large cross-section within the gas flow path, then the particle deposition on the substrate is greater than the particle deposition when the substrate adopts a shape presenting a small cross-section within the gas flow path.

[0004] There is a need for methods and apparatus to prevent or minimize particle contamination of substrates being processed. Summary of the invention

[0005] A method and apparatus for processing a semiconductor substrate are described. In one embodiment, a substrate processing apparatus is disclosed, comprising: a processing chamber; a substrate support disposed within the processing chamber; a plurality of lamps arranged in a lamp head and positioned proximate to the substrate support; a gas source for providing a purge gas in a lateral flow path across the substrate support; and a controller for differentially adjusting power provided to individual lamps of the plurality of lamps based on a direction of the flow path.

[0006] In another embodiment, a substrate processing device is disclosed, including: a processing chamber; a substrate support, which is disposed in the processing chamber; a lamp array, which is arranged in a lamp head and positioned close to the substrate support, the lamp array including at least an inner partition, a central partition and an outer partition, the outer partition corresponding to the periphery of the substrate support; a gas source, which is used to provide a purified gas in a lateral flow path across the substrate support; and a controller, which adjusts the power provided to the lamps in the outer partition based on the direction of the flow path.

[0007] In another embodiment, a method for processing a substrate is disclosed, comprising: heating a susceptor in a processing chamber using a lamp array, the lamp array comprising a plurality of lamps positioned below the susceptor, the plurality of lamps comprising an inner partition and an outer partition, the outer partition corresponding to a perimeter of the susceptor; flowing a purge gas in a lateral flow path across the susceptor, wherein the heating comprises providing power to one or more of the plurality of lamps in the outer partition of the lamp array without providing power to other lamps in the outer partition, the one or more lamps being positioned at a leading edge or a trailing edge of the susceptor based on the flow path; and transferring the substrate to the susceptor after the heating step. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Therefore, in order to be able to understand in detail the manner in which the above-mentioned features of the present disclosure are achieved, a more specific description of the present disclosure briefly summarized above may be obtained by reference to the embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the drawings only illustrate typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure, as the present disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a schematic cross-sectional view of a processing chamber according to one embodiment.

[0010] Figure 2A and 2B is an exploded isometric view of a susceptor and a substrate to be processed, showing the warping of the substrate to be processed.

[0011] Figure 2C and 2D Rotated 90 degrees Figure 2A and 2B A side view of a base and a substrate to be processed.

[0012] Figure 3A is an isometric view of the base and lamp head, showing one embodiment of differential heating of the base.

[0013] Figure 3B is an isometric view of the base and lamp head showing another embodiment of differential heating of the base.

[0014] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0015] A method and apparatus for preventing or minimizing particle contamination of a substrate to be processed is provided. In one embodiment, a processing chamber is disclosed, comprising: a susceptor disposed adjacent a lamp head. The lamp head comprises a plurality of energy sources, such as lamps, that direct electromagnetic energy toward a surface of the susceptor, thereby heating the susceptor. The lamp head comprises a plurality of concentric zones, and one or more of the zones comprises lamps that can be individually controlled. Individual control of one or more lamps provides enhanced temperature control of the susceptor.

[0016] Figure 1 1 is a schematic cross-sectional view of a processing chamber 100 according to one embodiment. The processing chamber 100 can be used to process one or more substrates, including a process of depositing a material on an upper surface of a substrate 108. The processing chamber 100 generally includes an energy module 102 for heating a back side 104 of a substrate support or pedestal 107 disposed within the processing chamber 100 and other components. The pedestal 107 can be a circular disk-shaped (e.g., disk-shaped) substrate support as shown. The pedestal 107 is within the processing chamber 100 and is located between an upper housing 128 and a lower housing 114 of the chamber 100. The substrate 108 (not to scale) can be brought into the processing chamber 100 through a loading port 103 and placed on the pedestal 107.

[0017] The susceptor 107 connected to the central axis 132 is shown in an elevated processing position, but is repositioned to a loading position below the processing position by an actuator (not shown) coupled to the central axis 132. A substrate to be processed, such as substrate 108, is transferred into the processing chamber 100 through the loading port 103 and placed on the lifting pins 105. The lifting pins 105 are coupled to shafts disposed about the central axis 132 and pass through through holes in the susceptor 107 when the susceptor 107 is in the loading position. The susceptor 107 can then be actuated upward in the axial direction 134 to the processing position to contact the substrate 108 on the front side 110 of the susceptor 107, wherein the device side 116 of the substrate 108 faces upward.

[0018] The susceptor 107 divides the interior volume of the processing chamber 100 into a processing gas region 156 (above the substrate) and a purge gas region 158 (below the susceptor 107) when in the processing position. The susceptor 107 is rotated by the central shaft 132 connected thereto during processing to minimize the effects of reactive precursor depletion and thermal and processing gas flow spatial anomalies within the processing chamber 100, thereby promoting uniform processing of the substrate 108. The susceptor 107 is supported by the central shaft 132, which also moves the substrate 108 in the axial direction 134 during loading and unloading and in some cases during processing of the substrate 108. The susceptor 107 is typically formed of a material with a low thermal mass or low heat capacity so that the susceptor will be quickly heated and cooled. The susceptor 107 here is formed of silicon carbide or graphite coated with silicon carbide to absorb the radiant energy from the energy module 102 and heat the substrate 108.

[0019] Gases may be provided to the gas inlet 121 from a gas source 123. The gas source 123 may provide purge gases and precursor gases that flow onto the device side 116 of the substrate 108. The gases are generally provided to an outlet port 127 of the chamber along a flow path 125 across the device side 116 of the substrate 108. The gases are exhausted through the outlet port 127 via a pump 129.

[0020] However, the gas flowing along the flow path 125 may contain particles entrained therein. For example, the purge gas flowing into the chamber during the transfer of the substrate to be processed may transport particles that fall on the substrate to be processed. Particles may fall off from the chamber wall, and the fallen particles are entrained into the flow path 125. In addition, the temperature of the susceptor may cause the substrate 108 to warp upon initial contact with the susceptor. Depending on the orientation of the warp relative to the direction of the flow path 125, the retention area of ​​the particles may be larger or smaller. If the substrate 108 adopts a shape that presents a large cross-section within the flow path 125, then the particle deposition is greater than the particle deposition when the substrate 108 adopts a shape that presents a small cross-section within the flow path 125.

[0021] In general, the upper housing 128 and the lower housing 114 are typically formed of a substantially optically transparent material, such as quartz, that allows electromagnetic energy from the energy module 102 to pass therethrough to the process gas region 156 .

[0022] The energy module 102 includes one or more lamps 141, or other electromagnetic radiation sources such as lasers, LEDs, and VCSELs, disposed in a housing 145. The energy module 102 is disposed adjacent to and below the lower housing 114 to heat the substrate 108 as the process gas passes over the substrate 105, thereby promoting a reaction that results in deposition of material onto the device side 116 of the substrate 108. Figure 1In the embodiment of the present invention, one or more lamps 109 are disposed above the upper housing 128 to provide electromagnetic energy to the device side 116 of the substrate 108, but the upper lamps are optional. A central shaft 132 passes through the energy module 102 and extends to the exterior of the processing chamber 100.

[0023] Figure 1 The energy module 102 heats the substrate 108 to a temperature in the range of about 200 degrees Celsius to about 1200 degrees Celsius, such as about 300 degrees Celsius to about 950 degrees Celsius. The energy module 102 may include an optional reflector 143 surrounding the lamps 141. The energy module 102 includes a housing 145 that houses the lamps 141 and can be cooled during or after processing by, for example, introducing a cooling fluid into channels located between the lamps 141. In some cases, the housing 145 may be in contact with the lower housing 114. The controller 160 controls the power supplied to each lamp 141 of the energy module 102.

[0024] A circular shield 167 may be optionally disposed around the pedestal 107 and coupled to the sidewalls of the chamber body 101. The shield 167 prevents or minimizes heat and / or light from leaking from the energy module 102 to the device side 116 of the substrate 108. In addition, the shield 167 absorbs electromagnetic energy from the energy module 102, which heats the shield 167 and preheats the process gas passing over the shield 167. The shield 167 may be made of CVD SiC-coated sintered graphite, SiC, or a similar opaque material that resists chemical decomposition by process and cleaning gases.

[0025] The reflector 122 may optionally be placed outside the upper housing 128 to reflect infrared light radiated from the substrate 108 back to the substrate 108. Based on the reflected infrared light, the heating efficiency of the substrate 108 will be improved by reflecting electromagnetic energy that would not otherwise be used to heat the substrate 108. A plurality of thermal radiation sensors 140, which may be pyrometers, are disposed in the processing chamber 100 for monitoring the temperature of the substrate 108. The sensors 140 are typically disposed at different locations in the processing chamber 100. Some sensors may be disposed in the housing 145 to monitor the thermal state of the susceptor 107, while other sensors may be disposed in the reflector 122 to directly monitor the thermal state of the substrate 108. The sensors disposed in the housing 145 are typically located between the lamps and may benefit from cooling applied to the housing 145. The thermal sensors send data to the controller 160, which in turn may modulate the power of the lamps based on the data to control the process.

[0026] The energy module 102 is used to heat the susceptor 107 before placing the substrate on the susceptor 107. For example, the energy module 102 provides thermal energy to the back side 104 of the susceptor 107 before the substrate to be processed is positioned on the susceptor 107. The inventors have found that heating the susceptor 107 using the energy module 102 before transferring the substrate to be processed to the substrate 107 causes the substrate to warp when in contact with the susceptor 107.

[0027] Warping is primarily caused by uneven heating and, therefore, uneven thermal expansion across the substrate. Differential or preferential local heating from lamp power management can adjust thermal expansion within the substrate and cause the substrate to assume certain warped shapes, making it more susceptible to particle addition and other issues.

[0028] As discussed above, warping results in particle contamination of the substrate, depending on the orientation of the warping relative to the flow path 125. For example, the retention area of ​​particles may be larger or smaller, depending on the orientation of the warping relative to the direction of the flow path 125. If the substrate 108 adopts a shape that presents a large cross-section within the flow path 125, then particle deposition is greater than when the substrate 108 adopts a shape that presents a small cross-section within the flow path 125. Differential heating of the susceptor 107 can counteract thermal gradients in the susceptor 107 that cause undesirable warping, thereby minimizing or controlling deformation of the substrate to be processed.

[0029] The lamps 141 of the energy module 102 can be divided into radial partitions, such as an outer partition 170, a central partition 172, and an inner partition 174. Although divided into three partitions 170, 172, and 174, the energy module 102 can also include only two partitions, such as an inner partition 174 and an outer partition 170. One or more individual lamps 141 within each of the outer partition 170, the central partition 172, and / or the inner partition 174 are individually controlled.

[0030] In one embodiment, the first power supply 162 controls the application of power to each of the inner partition 174 and the central partition 172. For example, all the lamps 141 of the inner partition 174 and the central partition 172 are controlled by the first power supply 162, while the second power supply 164 is used to independently control each of the lamps 141 of the outer partition 170. Here, the second power supply 164 includes a plurality of thyristors 176, such as silicon controlled rectifiers (SCR). Each thyristor 176 is dedicated to the lamp 141 to independently control the power provided to each lamp 141 of the outer partition 170 so as to control the heating of the periphery 178 of the base 107. Similarly, the third power supply 166 can be used to control the application of power to the lamp 109.

[0031] Figures 2A-2D is an exploded view of the susceptor 107 and the substrate to be processed, which shows various warp profiles of the substrate to be processed. Figure 2A and 2B is an exploded isometric view of the susceptor 107 and the substrate to be processed, Figure 2C and 2D Rotated 90 degrees Figure 2A and 2B The substrate to be processed is shown in FIG. Figure 2A and 2C The substrate 200A is shown as being warped, and Figure 2B and 2D The substrate 200B is shown as warped. The airflow direction 205 is Figure 2A and 2B Indicated by arrows and Figure 1 The flow path 125 shown and described in FIG. 1 is the same. Figure 2C and 2D The gas flow direction is not shown in the figure because the gas flow direction points into the paper due to the rotation of the view. The gas flow may be a purge gas that flows during the substrate transfer process. Figure 2A and 2B The warping of the substrate to be processed in the pedestal 107 is caused by the amount of change in the temperature distribution of the pedestal 107. In addition, changes in the transport process (including switching of the substrate to be processed and tilting of the pedestal 107), as well as the position of the lamp 141 and / or the mass of the lamp 141 can cause the substrate to be processed to warp into an arbitrary shape or orientation. As explained in more detail below, this warping presents a profile relative to the airflow direction 205, which can provide a larger surface area for particles entrained in the airflow to adhere to the substrate to be processed. The shape and / or orientation of the warping can result in a larger or smaller surface area for particles to adhere to the substrate to be processed, depending on the orientation of the substrate to be processed relative to the airflow direction 205.

[0032] exist Figure 2A and 2B In , the substrate to be processed (eg, the warped substrate 200A or the warped substrate 200B) is warped so that a midpoint of curvature (which is indicated by a dotted line 207) is formed. Figure 2A In FIG. 2 , substrate 200A is oriented in processing chamber 100 such that midpoint of curvature 207 is oriented in a direction substantially perpendicular to gas flow direction 205 . Figure 2B , the midpoint of curvature 207 is oriented in a direction substantially parallel to the airflow direction 205 .

[0033] Although warping is not desired, the orientation of the warped substrate 200B presents a profile relative to the gas flow direction 205 that is less likely to be contaminated by particles entrained in the gas flow. For example, in the case of the warped substrate 200A, the profile 210 facing the gas flow direction 205 is greater than the profile 215 of the warped substrate 200B facing the gas flow direction 205 due to the warping relative to the orientation of the gas. In this way, differential heating of the susceptor 107 as disclosed herein is provided to minimize warping so that the substrate to be processed does not warp (or greatly reduces warping). Alternatively, differential heating of the susceptor 107 as disclosed herein is provided to control the warping to present the profile 215 (opposite to the profile 210 of the warped substrate 200A).

[0034] Figure 3A 1 is an isometric view of a base 107 having an energy module 102 positioned below the base 107. Leading edge lamps 300 and trailing edge lamps 305 (relative to the airflow direction 205) and other lamps 310 in the outer partition 170 are shown. For clarity, the inner partition 174 and the center partition 172 are not shown. In this embodiment, the leading edge lamps 300 and the trailing edge lamps 305 are powered by the second power supply 164, while the other lamps 310 are powered at a lower energy level. Alternatively or additionally, the lamps 310 of the inner partition 174 and the center partition 172 are uniformly powered (e.g., at the same power level). Therefore, the base 107 is heated non-uniformly, which heats the leading edge 315 and the trailing edge 320 of the periphery 178 of the base 107 relative to the airflow direction 205 to a temperature greater than that of other portions of the periphery 178 of the base 107. This differential heating reduces, minimizes, or controls warping of a substrate positioned on the susceptor 107 to be processed.

[0035] Figure 3B 1 is an isometric view of a pedestal 107 having an energy module 102 positioned below the pedestal 107. One or more leading edge lamps 300 are shown (relative to the airflow direction 205) and other lamps 310 in the outer partition 170 of the lamp head 145. For clarity, the inner partition 174 and the center partition 172 are not shown. In this embodiment, one or more leading edge lamps 300 are powered by the second power supply 164, while other lamps 310 are not powered at a lower energy level. Alternatively or additionally, the lamps 310 of the inner partition 174 and the center partition 172 are uniformly powered (e.g., at the same power level). Therefore, the pedestal 107 is heated non-uniformly, which heats the leading edge 315 of the perimeter 178 of the pedestal 107 to a temperature greater than other portions of the perimeter 178. This differential heating reduces, minimizes, or controls warping of a substrate to be processed positioned on the pedestal 107.

[0036] The above-described embodiments relate to controlling anisotropy in heating a substrate to be processed to minimize, prevent or control warping of the substrate to be processed. In some embodiments, the controlled warping provided by the methods and apparatus disclosed herein provides a consistent shape, contour and / or warp orientation in the substrate to be processed, which minimizes particle adhesion to the substrate to be processed. The above-described embodiments of differential heating of the susceptor 107 may be provided only for at most about 10 seconds to about 40 seconds before the substrate to be processed contacts the susceptor 107, after which the substrate to be processed flattens and / or uniformly contacts the susceptor 107.

[0037] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be envisaged without departing from the basic scope thereof, and the scope of the invention is determined by the appended claims.

Claims

1. A substrate processing device, comprising: a processing chamber; a substrate support disposed in the processing chamber; a plurality of lamps disposed in a lamp head and positioned proximate to the substrate support; a gas source for providing a purge gas in a lateral flow path across the substrate support, the flow path defining a leading edge and a trailing edge of the substrate support; as well as and a controller that differentially adjusts power supplied to individual lamps among the plurality of lamps based on the direction of the flow path before a substrate is placed on the substrate support, such that, for lamps among the plurality of lamps in outer zones corresponding to the periphery of the substrate support, lamps located at the leading edge of the substrate support or lamps located at the leading edge and the trailing edge of the substrate support are supplied with greater power than other lamps in the outer zones, thereby heating the leading edge or the leading edge and the trailing edge of the substrate support to a temperature greater than that of other portions of the periphery of the substrate support. 2 . The substrate processing apparatus of claim 1 , wherein the plurality of lamps are disposed in at least two partitions, and each of the partitions includes two or more lamps. 3 . The substrate processing apparatus of claim 2 , wherein the at least two zones are concentric and include an inner zone, a center zone, and the outer zone. 4 . The substrate processing apparatus of claim 2 , wherein the controller controls power supplied to any one of the one or more selection lamp partitions positioned at the leading edge or the trailing edge. 5 . The substrate processing apparatus of claim 4 , wherein the one or more selection lamp subareas positioned at the leading edge or the trailing edge are part of a concentric arrangement.

6. The substrate processing apparatus of claim 4, wherein the controller provides higher power to any selected lamp partition at the leading edge than anywhere else.

7. The substrate processing apparatus of claim 4, wherein the controller provides higher power to any selected lamp partitions at the leading edge and the trailing edge than anywhere else.

8. The substrate processing apparatus of claim 3, wherein the controller controls power of the lamps in outer concentric zones positioned at the leading edge and the trailing edge.

9. The substrate processing apparatus of claim 2, wherein the controller supplies higher power to the lamp at the leading edge than to other lamps.

10. The substrate processing apparatus of claim 2, wherein the controller supplies higher power to the lamps at the leading edge and the trailing edge than to other lamps.

11. A substrate processing device, comprising: a processing chamber; a substrate support disposed in the processing chamber; a lamp array disposed in a lamp head and positioned proximate to a substrate support, the lamp array comprising at least an inner partition and an outer partition, the outer partition corresponding to a perimeter of the substrate support; a gas source for providing a purge gas in a lateral flow path across the substrate support, the flow path defining a leading edge and a trailing edge of the substrate support; as well as and a controller that adjusts the power provided to the lamps in the outer zone based on the direction of the flow path before a substrate is placed on the substrate support, so that, for the lamps of the lamp array in the outer zone, the lamps located at the leading edge of the substrate support or the lamps located at the leading edge and the trailing edge of the substrate support are provided with greater power than other lamps in the outer zone, thereby heating the leading edge or the leading edge and the trailing edge of the substrate support to a temperature greater than that of other portions of the periphery of the substrate support. 12 . The substrate processing apparatus of claim 11 , wherein the controller controls power supplied to the lamps in the outer partition positioned at the leading edge or the trailing edge.

13. The substrate processing apparatus of claim 12, wherein the controller provides power to a portion of the lamps at the leading edge and provides a lower power level to other lamps in the outer zone.

14. The substrate processing apparatus of claim 12, wherein the controller provides power to a portion of the lamps at the leading edge and the trailing edge and provides a lower power level to other lamps in the outer zone. 15 . The substrate processing apparatus of claim 11 , wherein the controller controls power supplied to the lamps in the outer partitions positioned at the leading edge and the trailing edge.

16. The substrate processing apparatus of claim 12, wherein the controller supplies higher power to the lamp at the leading edge than to other lamps.

17. The substrate processing apparatus of claim 12, wherein the controller provides higher power to the lamps at the leading edge and the trailing edge than to other lamps.

18. A method for processing a substrate, the method comprising: heating a susceptor in a processing chamber using a lamp array, the lamp array comprising a first plurality of lamps positioned below the susceptor and a second plurality of lamps positioned above the susceptor, the first plurality of lamps comprising an inner zone, a central zone, and an outer zone, the outer zone corresponding to a perimeter of the susceptor; flowing a purge gas in a lateral flow path across the susceptor, the flow path defining a leading edge and a trailing edge of the susceptor, wherein the step of heating comprises: Before transferring the substrate to the pedestal, providing power to one or more lamps of the first plurality of lamps in the outer partition of the lamp array that are positioned at a leading edge of the pedestal or at both a leading edge and a trailing edge of the pedestal without providing power to other lamps in the outer partition, thereby heating the leading edge or the leading edge and a trailing edge of the pedestal to a temperature greater than other portions of the perimeter of the pedestal; as well as The substrate is transferred to the susceptor after the heating step.

19. The method of claim 18, wherein a controller provides power to a lamp of the first plurality of lamps located at the leading edge and a lamp of the first plurality of lamps located at the trailing edge.

20. The method of claim 18, wherein a controller provides power to two or more of the first plurality of lamps located at the leading edge.

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