Window for rapid heat treatment chamber

Abstract

A window assembly for a thermal processing chamber applicable for thermal processing of semiconductor substrates is provided. The window assembly includes an upper window, a lower window, and a plurality of linear reflectors disposed between the upper and lower windows. The plurality of linear reflectors extend lengthwise parallel to one another and parallel to a plane of the window assembly. The window assembly includes a pressure control region defined between the upper and lower windows and a side of each linear reflector.

Description

Technical Field

[0001] The embodiments disclosed herein generally relate to the heat treatment of semiconductor substrates. More particularly, the embodiments disclosed herein relate to windows for rapid thermal processing chambers for the heat treatment of semiconductor substrates.

Background Art

[0002] Rapid thermal processing (RTP) is a heat treatment technique that enables rapid heating and cooling of substrates such as silicon wafers. Examples of RTP substrate processing applications include, among others, annealing, dopant activation, rapid thermal oxidation, and silicidation. In some examples, the peak processing temperature can range from about 450°C to about 1100°C. In one type of RTP chamber, heating is performed using a number of lamps disposed in a lamp head above or below the substrate being processed. The lamps can be arranged in a matrix, honeycomb, or linear configuration in the RTP lamp head of the RTP chamber.

[0003] The body portion of the RTP chamber located between the lamp and the substrate includes a window to allow radiation to pass through. The body portion of the RTP chamber seals the processing region in which the substrate is located during processing. The pressure in the processing region can be controlled during processing. For example, depending on the RTP substrate processing application, atmospheric pressure or vacuum pressure can be used in the processing region. When the processing region is at vacuum pressure, there is a pressure difference between the inside and outside of the RTP chamber. To prevent damage to the RTP chamber caused by the pressure difference, an RTP chamber that can operate at vacuum pressure can include a thicker window compared to an RTP chamber that can only operate at atmospheric pressure. However, to accommodate the use of a thicker window, the corresponding lamp may be more distant from the substrate, thereby reducing temperature control uniformity.

[0004] Therefore, there is a need for an improved RTP chamber that operates at vacuum pressure. [Overview of the project]

[0005] Embodiments of this disclosure generally relate to a rapid heat treatment chamber for heat treatment of semiconductor substrates and components of the rapid heat treatment chamber, such as windows.

[0006] In one embodiment, a window assembly for a heat treatment chamber applicable for semiconductor manufacturing is provided, the window assembly comprising an upper window, a lower window, and a plurality of linear reflectors disposed between the upper and lower windows. The plurality of linear reflectors extend longitudinally, parallel to each other and parallel to the plane of the window assembly. The window assembly includes pressure control regions defined between the upper and lower windows and the sides of each linear reflector.

[0007] In another embodiment, a window assembly for a heat treatment chamber applicable to semiconductor manufacturing includes a window body and a plurality of lenses disposed on the surface of the window body. The optical axis of each lens is perpendicular to the plane of the window body.

[0008] In another embodiment, a heat treatment chamber applicable for semiconductor manufacturing includes one or more side walls enclosing a processing area, a substrate support within the processing area having a substrate support surface, and a window assembly disposed above one or more side walls. The window assembly includes an upper window, a lower window, and a plurality of linear reflectors disposed between the upper and lower windows. The plurality of linear reflectors extend longitudinally, parallel to each other and parallel to the plane of the window assembly. The window assembly includes a pressure control area defined between the upper and lower windows and the sides of each linear reflector. The heat treatment chamber includes a lamp head disposed above the window assembly.

[0009] A more detailed description of the Disclosure, which is briefly summarized above, can be obtained by referring to embodiments shown in part in the accompanying drawings, so that the features described above can be understood in detail. However, it should be noted that the accompanying drawings only illustrate general embodiments of the Disclosure and should not be considered to limit the scope of the Disclosure, as the Disclosure may lead to other equally valid embodiments. [Brief explanation of the drawing]

[0010] [Figure 1A] This is a side cross-sectional view of a heat treatment chamber according to one embodiment. [Figure 1B-1C] Figure 1A is a schematic top view showing two different exemplary window assemblies that may be used in a heat treatment chamber. [Figure 1D] This is an enlarged side cross-sectional view of a portion of the heat treatment chamber in Figure 1A, showing an exemplary reflector in more detail. [Figure 2A] Figure 1A is an enlarged side cross-sectional view showing another exemplary reflector that may be used in a window assembly. [Figure 2B] Figure 1A is an enlarged side cross-sectional view showing yet another exemplary reflector that may be used in a window assembly. [Figure 3A] This is a side cross-sectional view of the heat treatment chamber in Figure 1A, showing a different window assembly installed with the heat treatment chamber in Figure 1A. [Figure 3B] Figure 3A is a schematic top view of the window assembly. [Figure 3C] Figure 3A is an enlarged side cross-sectional view of a portion of the heat treatment chamber. [Figure 4] Figure 3A is an enlarged side cross-sectional view showing another exemplary window assembly that may be used in a heat treatment chamber. [Modes for carrying out the invention]

[0011] To facilitate understanding, common words are used where possible to specify equivalent elements common to the figures. Elements disclosed in one embodiment are intended to be advantageously utilized in other embodiments without specific detail.

[0012] This disclosure generally relates to the heat treatment of semiconductor substrates. More specifically, embodiments disclosed herein relate to windows for rapid heat treatment chambers for the heat treatment of semiconductor substrates.

[0013] Apparatus and / or methods disclosed herein provide an improved window for vacuum pressure RTP processes. In one exemplary process, post-nitridation annealing of silicon oxynitride (e.g., SiON) films is performed at low Torre (e.g., 0.1–5 Torre) oxygen partial pressures. Since ultra-high dilution at atmospheric pressure is required to achieve low Torre oxygen partial pressures, the post-nitridation annealing process is carried out at vacuum pressure. In another example, since hydrogen-oxygen combustion occurs only at pressures below approximately 10 Torre, vacuum pressure RTP is used in radical oxidation processes that utilize atomic oxygen radicals produced by hydrogen-oxygen combustion. In yet another example, since atomic radicals are unstable at pressures greater than approximately 3 Torre, vacuum pressure RTP is used with atomic oxygen radicals produced in a remote plasma source. In particular, each of the processes described above benefits from the apparatus and / or methods of this disclosure.

[0014] Embodiments disclosed herein provide a window assembly comprising a plurality of linear reflectors that reflect radiation emitted by one or more linear lamps of a heat treatment chamber, thereby directing the radiation. The linear reflectors reduce or prevent zone overlap of radiation within the treatment area or on the substrate surface, resulting in improved temperature control uniformity compared to conventional reflectors.

[0015] Embodiments disclosed herein provide a linear reflector having molded and / or inclined sides to improve the directional control of radiation incident on the sides, thereby improving temperature control uniformity compared to conventional reflectors.

[0016] Embodiments disclosed herein provide linear lamps and linear reflectors sized to generally conform to the shape of a substrate support and / or a substrate disposed thereon, so that lamp power is not wasted heating areas outside the area of ​​the substrate.

[0017] Embodiments disclosed herein provide a window assembly comprising multiple lenses that improve the directivity and / or focusing of radiation emitted by one or more lamps in a heat treatment chamber and returning in a direction perpendicular to the plane of the window assembly, thereby improving zone radiation control and temperature control uniformity compared to conventional windows.

[0018] Embodiments disclosed herein provide a window assembly comprising a plurality of linear lenses that improve the directivity and / or focusing of radiation emitted by one or more linear lamps of a heat treatment chamber, so as to improve zone radiation control and temperature control uniformity compared to conventional windows.

[0019] Figure 1A is a side cross-sectional view of the heat treatment chamber 110. The heat treatment chamber 110 can be used for rapid heat treatment (RTP) of a substrate. As used herein, rapid heat treatment or RTP refers to an apparatus, chamber, or process capable of uniformly heating a substrate at a rate of about 50°C / second or more, for example, from about 75°C / second to about 100°C / second, or from about 150°C / second to about 220°C / second. In some examples, the ramp-down (cooling) rate in the RTP chamber may be in the range of about 30°C / second to about 90°C / second.

[0020] The heat treatment chamber 110 includes one or more sidewalls 150 that surround and / or enclose a processing region 118 for heat-treating a substrate 112, such as a silicon substrate. The heat treatment chamber 110 includes a base 153 that supports the one or more sidewalls 150. The heat treatment chamber 110 includes a window assembly 120 disposed above the one or more sidewalls 150, a lamp head 155 disposed above the window assembly 120, and a reflector assembly 178 disposed above the lamp head 155. The window assembly 120 is transparent to allow radiation to pass therethrough. "Radiation", as used herein, refers to any type of electromagnetic radiation (including, for example, thermal radiation including ultraviolet (UV) light, visible light, and infrared (IR) light). "Transparent", as used herein, means that most of the radiation of a given wavelength is transmitted. Thus, a "transparent" object, as used herein, is an object that transmits most of the incident radiation of a given wavelength of interest. As used herein, when an object is "transparent" to visible light, the object transmits most of the incident light of visible wavelengths. Similarly, when an object is "transparent" to infrared light, the object transmits most of the incident light of infrared wavelengths. Similarly, when an object is "transparent" to ultraviolet light, the object transmits most of the incident light of ultraviolet wavelengths.

[0021] The substrate support 111 is located within the processing region 118. The substrate support 111 is rotatable. The substrate support 111 includes an annular support ring 114 and a rotatable support cylinder 130. A rotatable flange 132 is disposed outside the processing region 118 and is magnetically coupled to the support cylinder 130. An actuator (not shown) may be used to rotate the flange 132 about the centerline 134 of the heat treatment chamber 110. In one example, the bottom of the support cylinder 130 can be magnetically levitated and rotated by a rotating magnetic field generated in a coil surrounding the support cylinder 130.

[0022] The substrate 112 is supported by the annular support ring 114 of the substrate support 111 around it. The edge lip 115 of the annular support ring 114 extends inward and contacts a part of the back side of the substrate 112 on the substrate support surface 117 of the edge lip 115. The substrate 112 is oriented such that the feature 116 already formed on the front surface of the substrate 112 faces the lamp head 155.

[0023] The port 113 to the processing region 118 of the heat treatment chamber 110 is used to transfer the substrate into and out of the heat treatment chamber 110. A plurality of lift pins 122, such as three lift pins, are extended and retracted to support the back side of the substrate 112 when the substrate 112 is disposed in or removed from the heat treatment chamber 110. Instead, the plurality of lift pins 122 can remain fixed while the substrate support 111 is moved to extend and retract the lift pins 122 with respect to the substrate support 111.

[0024] The upper side of the processing region 118 is defined by the window assembly 120. The window assembly 120 separates the lamp head 155 from the processing region 118. The window assembly 120 will be described in more detail below.

[0025] The lamp head 155 is used to heat the substrate 112 during heat treatment. The lamp head 155 includes a housing 160 and an array of lamps 170 disposed within the housing 160. The housing may be formed from a metal such as stainless steel or other suitable material. The array of lamps 170 includes a plurality of lamps 190. Examples of suitable lamps to be used as lamps 190 may be tungsten halogen lamps, mercury vapor lamps, infrared lamps, and ultraviolet lamps. The lamps 190 impart heat to the processing area 118 to raise the temperature of the substrate 112. As shown in Figure 1A, the lamps 190 are linear lamps arranged left and right, extending longitudinally parallel to each other and parallel to the plane of the window assembly 120. The plane of the window assembly refers to a plane that passes through the window assembly longitudinally (i.e., aligned with the major axis of the window assembly) and / or a plane that is parallel to the top or bottom surface of the window assembly. As used herein, a “linear lamp” refers to a lamp having a radiation source (e.g., a UV, IR, or visible light source) that extends longitudinally in a first direction for a distance longer than the width of the radiation source measured in a second direction perpendicular to the first direction. In one example, a linear lamp includes an elongated bulb surrounding one or more radiating wires or filaments. In some other examples, the lamp 190 may be a circular or single-source lamp having radiation sources of substantially equal dimensions in the first and second directions. In such examples, the lamps 190 may be arranged in a matrix or honeycomb configuration.

[0026] In one example, one or more of the lamps 190 may be segmented lamps configured to direct heat to control the temperature of a specific zone on the substrate 112, such as a ring-shaped zone on the substrate 112, when the substrate 112 is rotated by a rotatable substrate support 111. The radiating elements of the segmented lamps, such as filaments, may be arranged in zones corresponding to areas of the substrate 112 on the substrate support 111 to be heated, for example, radial zones. One or more sensors, such as a pyrometer, may be used to monitor different zones, thereby enabling separate temperature control of different areas of the substrate 112. For example, more heat may be applied to the outer edge to offset the increased surface area around the outer edge of the substrate 112. The segmented lamps, and / or emitters of the segmented lamps, may be arranged across the array 170 from one edge to the other, to give zones of any desired shape or profile, such as linear zones, or square or rectangular zones that may be concentric or eccentric. The lamps 190 are described in more detail below.

[0027] A reflector assembly 178 is positioned above the housing 160 of the lamp head 155 to reflect radiation back towards the substrate 112. The surface of the reflector assembly 178 may be plated with a reflective material such as gold, aluminum, or stainless steel, such as polished stainless steel. Each lamp 190 is positioned in a reflective cavity 176. The top of each reflective cavity 176 is defined by a reflector 175. In one example, the reflector 175 may extend to either side of the corresponding lamp 190. The reflector 175 may guide, focus, and / or shape the radiation from the lamp 190.

[0028] In some examples, the reflector assembly 178 may include cooling channels to help remove excess heat from the lamp head 155 and assist in cooling the substrate 112 during lamp-down by the use of a coolant, such as water. While the reflector assembly 178 has been shown to have a substantially flat shape, in some other examples, the reflector assembly 178 may have a concave shape.

[0029] The window assembly 120 includes an upper window 121, a lower window 123, a plurality of reflectors 124 disposed between the upper window 121 and the lower window 123 and supporting the upper window 121 and the lower window 123, and a pressure control region 125 defined between the upper window 121 and the lower window 123 and the sides of each reflector 124. Each window may be formed from a transparent material such as quartz or fused quartz (amorphous quartz). Each reflector may be formed from a reflective material such as gold, aluminum, or stainless steel such as polished stainless steel, or may be plated with such a reflective material. Generally, the reflectors 124 reflect radiation emitted by the lamp 190 and give directionality to that radiation in order to reduce or prevent zone overlap of radiation within the processing region 118 and / or on the substrate surface. A pressure control line 127 fluidly connects the pressure control region 125 and the pressure control assembly 129. The pressure control assembly 129 may include a vacuum pump, a source of purge gas (e.g., helium or another inert gas), and a throttle valve for adjusting the pressure within the pressure control region 125. In one example, the pressure control region 125 may operate at a vacuum pressure ranging from about 5 Torr to about 20 Torr.

[0030] The pressure control region 125 is formed from a plurality of interconnected (e.g., fluid-connected) lower regions 126 that are laterally separated from each other in a direction parallel to the plane of the window assembly 120 and aligned with each of the corresponding ramps 190 in a direction perpendicular to the plane of the window assembly 120. As shown in the figure, the lower regions 126 are connected to each other by corresponding flow paths 131 disposed within the body of each reflector 124. The flow paths 131 shown are parallel to the plane of the window assembly 120. However, in some other examples, the flow paths 131 may extend at obtuse or acute angles with respect to the plane of the window assembly 120. In some other examples, the lower regions 126 may be connected to each other by corresponding flow paths routed around each reflector 124 (e.g., above each reflector 124 and below the upper window 121, or below each reflector 124 and above the lower window 123).

[0031] As shown in the figure, cooling channels 133 are formed in the body of each reflector 124 to help remove excess heat from the window assembly 120. The cooling channels 133 extend longitudinally through each reflector 124, perpendicular to the direction of the flow path 131 and parallel to the plane of the window assembly 120. The cooling channels 133 form a continuous cooling path 135 extending through each reflector 124 (shown in Figures 1B and 1C). The window assembly 120 will be described in more detail below.

[0032] The processing area 118 is defined on its underside by the base 135 of the heat treatment chamber 110. The base 135 includes a reflector plate 128 disposed beneath the edge lip 115 of the annular support ring 114. The reflector plate 128 extends parallel to the back surface of the substrate 112 facing the reflector plate 128, over an area larger than such a back surface. The reflector plate 128 reflects radiation emitted from the substrate 112 back towards the substrate 112 to improve the apparent emissivity of the substrate 112. The top surface of the reflector plate 128 and the back surface of the substrate 112 form a reflective cavity to improve the effective emissivity of the substrate 112 in order to improve the accuracy of temperature measurements. The distance between the substrate 112 and the reflector plate 128 can be approximately 3 mm to approximately 9 mm, and the aspect ratio of the width to the thickness of the reflective cavity can be greater than approximately 20. The top surface of the reflector plate 128 may be formed from aluminum, and may also have a surface coating made of a different material, such as a highly reflective material such as silver or gold, or a multilayer dielectric mirror. In some examples, the reflector plate 128 may have an irregular or textured top surface, or a top surface that is black or other colored to better resemble a blackbody wall. The reflector plate 128 is disposed on a base 135. The base 135 may include cooling channels (not shown) to help remove excess heat from the substrate 112. The cooling channels may be used, particularly during ramp-down, by the use of a coolant such as water.

[0033] The base 135 includes a plurality of temperature sensors 140, indicated as a pyrometer, for measuring the temperature across the radius of the rotating substrate 112. Each sensor 140 is coupled through an optical light pipe 142 and an opening in the reflector plate 128 to face the back side of the substrate 112. The light pipe 142 may be formed from materials such as sapphire, metal, or silica fiber.

[0034] A controller 144 may be used to control the temperature of the substrate 112 during processing. For example, the controller 144 may be used to supply a relatively constant amount of power to the lamps 190 during a particular step of the thermal process. The controller 144 may change the amount of power supplied to the lamps 190 for different substrates or different thermal treatment steps performed on the same substrate. The controller 144 may use signals from the sensor 140 as input to control the temperature of different radial zones on the substrate 112. The controller 144 may adjust the voltage supplied to different lamps 190 to dynamically control the radiant heating intensity and pattern during processing. In one example, the lamps 190 may be powered using a DC power supply. In another example, the lamps 190 may be powered using an AC power supply and a rectifier, such as a silicon-controlled rectifier.

[0035] The pyrometer generally measures light intensity within a narrow wavelength band of approximately 40 nm, for example, within the range of approximately 700 nm and approximately 1000 nm. The controller 144 or other instrument can convert the measured light intensity into a temperature reading using any preferred method.

[0036] The illustrated heat treatment chamber 110 has an upper heating configuration in which the lamp 190 is positioned above the substrate 112, but it is intended that a lower heating configuration in which the lamp 190 is positioned below the substrate 112 may benefit from this disclosure and be used in addition to or instead of the illustrated upper heating configuration. In some examples, the front surface of the substrate 112 on which the feature 116 is formed may not be facing the lamp head 155 (i.e., facing the sensor 140) during processing.

[0037] Figures 1B and 1C are schematic top views showing two different exemplary window assemblies that may be used in the heat treatment chamber 110 of Figure 1A. The ramp 190 is shown in Figures 1B and 1C, but the reflector assembly 178 is omitted from the figures for clarity. Referring together to Figures 1B and 1C, the cooling path 135 has an inlet 135a, an outlet 135b, and a connector 135c coupled in series between each cooling channel 133 (shown as a phantom). The connector 135c may be routed inside or outside the window assembly 120 as desired.

[0038] As described above, the ramps 190 are linear ramps arranged left and right, extending longitudinally parallel to each other and parallel to the plane of the window assembly 120. In Figure 1B, each ramp 190a extends over substantially the entire length of the window assembly 120a, whereas in Figure 1C, at least one of the ramps 190b-190f extends over only a portion (for example, less than the entire length) of the window assembly 120b. The reflectors 124 are linear reflectors arranged left and right, extending longitudinally parallel to each other and parallel to the plane of the window assembly 120. As used herein, “linear reflector” refers to a reflector that extends longitudinally in the first direction for a distance longer than the width of the reflector measured in a second direction perpendicular to the first direction. In some other examples, the reflectors may be circular with dimensions approximately equal in the first and second directions. In such examples, the reflectors may be arranged in a matrix or honeycomb configuration that matches the configuration of the lamp.

[0039] As shown in the top view, the reflectors 124 and ramps 190 are arranged alternately with respect to each other in directions perpendicular to the longitudinal direction of the reflectors 124 and parallel to the plane of the window assembly 120. In Figure 1B, each reflector 124a extends over substantially the entire length of the window assembly 120a, while in Figure 1C, at least one of the reflectors 124b–124f extends over only a portion of the length of the window assembly 120b. In some examples, the window assembly 120 is sized to fit within the housing 160 of the heat treatment chamber 110 such that the length of the window assembly 120 corresponds to the length of the treatment area 118. In such examples, each reflector 124a shown in Figure 1B may extend over substantially the entire length of the treatment area 118, while at least one of the reflectors 124b–124f shown in Figure 1C extends over only a portion of the length of the treatment area 118.

[0040] Referring to the window assembly 120a shown in Figure 1B, each lamp 190a has an equal length 196a which is longer than the diameter of the substrate 112 (shown as a phantom). As shown, the length of each reflector 124a is approximately equal to the length 196a of each lamp 190a. One advantage of the window assembly 120a is that such an array 170a having lamps 190a and reflectors 124a of equal length is relatively easy and inexpensive to manufacture compared to more complex designs (e.g., designs with components of different lengths, such as those shown in Figure 1C).

[0041] Referring to the window assembly 120b shown in Figure 1C, the ramps 190b–190f have different lengths. The longest ramp, 190b, which can be aligned with the radial center of the processing area 118 and / or substrate 112, may be approximately the same length as each ramp 190a in Figure 1B, 196a. The ramp array 170b shown in Figure 1C is symmetrical with respect to the central ramp 190b. Therefore, only the ramps 190b–190f on one side of the array 170b are labeled. In some other examples, the ramp array may be asymmetrical. Although only the shortest ramp, 190f, has a length of 196f, the lengths of each of the ramps 190c, 190d, 190e, and 190f decrease sequentially from the radial center of the processing area 118 and / or substrate 112 to the outer edge. Each of the lamps 190b to 190f extends beyond the outer edge of the substrate support 111 and / or substrate 112 such that the entire area of ​​the substrate 112 receives radiation emitted from at least one of the lamps 190b to 190f.

[0042] As shown in the figure, the reflectors 124b to 124f are sized according to the lengths of adjacent lamps among the lamps 190b to 190f. The reflectors 124b to 124f shown in Figure 1C are symmetrical with respect to the central lamp 190b. Therefore, only the reflectors 124b to 124f on one side of the central lamp 190b are labeled. In some other examples, the arrangement of reflectors may be asymmetrical. Similar to the lamps, the lengths of each reflector 124b, 124c, 124d, 124e, and 124f decrease sequentially from the radial center of the processing area 118 and / or the substrate 112 to the outer edge. Each of the reflectors 124b to 124f extends beyond the outer edge of the substrate 112. In comparison with Figure 1B, the lamps 190b-190f and reflectors 124b-124f in Figure 1C are sized to generally conform to the shape of the substrate support 111 and / or substrate 112 so that lamp power is not wasted heating areas outside the area of ​​substrate 112.

[0043] Figure 1D is an enlarged side cross-sectional view of a portion of the heat treatment chamber 110 of Figure 1A, showing the reflector 124 in more detail. The reflector 124 supports the upper window 121 from below and separates the upper window 121 and the lower window 123 in order to define a pressure control region 125 between the upper window 121 and the lower window 123. The reflector 124 has reflective sides 136 to reduce or prevent zone overlap of radiation emitted by the lamps 190 by reflecting the wide-angle radiation incident on the sides 136 back towards the region of the substrate 112 that is aligned with each of the corresponding lamps 190 in a direction perpendicular to the plane of the window assembly 120. The reflector 124 may be formed relatively thin, about 1 cm to about 3 cm in a direction perpendicular to the plane of the window assembly 120, in order to limit energy absorption or other energy loss from the radiation incident on the sides 136. Therefore, the reflector 124 is shown as having a height in the direction perpendicular to the plane of the window assembly 120 that is greater than its width in the direction parallel to the plane of the window assembly 120, but in some other examples, the width may be greater than or equal to the height.

[0044] The reflection of radiation incident on the side surfaces 136 of the reflector 124 can be directionally controlled based on the shape and / or angle of each side surface 136. As shown in Figure 1D, the reflector 124 has a rectangular cross-section and flat side surfaces 136 that are parallel to each other and perpendicular to the plane of the window assembly 120.

[0045] Figures 2A and 2B are enlarged side cross-sectional views showing two other exemplary reflectors 224a and 224b that may be used in the window assembly 120 of Figure 1A. In some examples, the cross-sectional shape of each reflector may be a (tapered) trapezoid (Figure 2A), hourglass (Figure 2B), square, triangular, oval, rhombic, any other suitable two-dimensional geometric or polygonal shape, or a combination thereof. In some examples, the corresponding sides 236a and 236b of reflectors 224a and 224b may be tapered, bent, concave, convex, or have any other suitable cross-sectional profile, for example, at a single angle (Figure 2A) or two different angles (Figure 2B) (double tapered). In some examples, the corresponding sides 236a, 236b of the same reflectors 224a, 224b may be separated outward from each other in the downward direction (i.e., toward the lower window 123) (Figure 2A), moved inward toward each other in the downward direction, or partially moved toward and partially separated in the downward direction (Figure 2B). In some implementations, the use of reflectors with non-parallel sides can improve the overall efficiency of the window assembly by further reducing zone overlap and / or improving the directional control of radiation emitted by the ramp 190 compared to reflectors with parallel sides.

[0046] Figure 3A is a side cross-sectional view of the heat treatment chamber 110 of Figure 1A, showing a different window assembly 320 installed with the heat treatment chamber 110 of Figure 1A. Figure 3B is a schematic top view of the window assembly 320 of Figure 3A. Figure 3C is an enlarged side cross-sectional view of a portion of the heat treatment chamber 110 of Figure 3A, showing the window assembly 320 in more detail. For clarity, Figures 3A to 3C will be described together in this specification. The window assembly 320 includes a window body 321 having an upper surface 323 and a lower surface 324. The upper surface 323 refers to the surface facing the ramp 190, which is at least partially shown by dashed lines in Figures 3A to 3B. The lower surface 324 refers to the surface opposite the upper surface 323, which faces the treatment chamber 118. As shown, the lower surface 324 is substantially flat.

[0047] The window body 321 has a plurality of lenses 325 extending upward from the top surface 323. The optical axis 337 of each lens 325 (shown in Figure 3C) is perpendicular to the plane of the window body 321. The lenses 325 are spaced laterally apart from each other in a direction parallel to the plane of the window body 321. Each lens 325 aligns with the corresponding lamp 190 along the axis 337. In some examples, each lens 325 and the corresponding lamp 190 may have approximately the same width when measured parallel to the plane of the window body 321. In one example, the width of the lens 325 and the corresponding lamp 190 may be approximately 1 cm. As shown in the figure, each lens 325 has a convex shape that is thicker in the center than at the edges in order to change the direction of wide-angle radiation and return it towards the axis 337, which may be the vertical axis. For example, the thickness T1 measured between the outer surface 326 and the bottom surface 324 of each lens 325 is greater than the thickness T2 measured between the top surface 323 and the bottom surface 324. As a result, the outer surface 326 of each lens 325 is closer to the corresponding lamp 190 than the upper surface 323 of the window body 321.

[0048] As shown in Figure 3B, the lenses 325 are linear lenses arranged horizontally and extending longitudinally parallel to each other and parallel to the plane of the window assembly 320. “Linear lens” as used herein refers to a lens having a linear shape that extends longitudinally in the first direction by a distance longer than the width of the lens measured in the second direction perpendicular to the first direction. In some other examples, the lenses may be circular with dimensions approximately equal in the first and second directions. In such examples, the lenses may be arranged in a matrix or honeycomb arrangement that matches the arrangement of the lamp.

[0049] In one example, each lens 325 may be a Fresnel lens having a series of concentric annular rings assembled on a flat surface. Fresnel lenses can capture a larger portion of wide-angle light compared to conventional lenses. Fresnel lenses can be fabricated to be much thinner than comparable conventional lenses. Therefore, one advantage of using Fresnel lenses in the window assembly 320 is that the lamp 190 can be positioned closer to the substrate 112 compared to conventional lenses, thereby improving temperature control uniformity.

[0050] The focal length of each lens 325 can range from approximately 5 mm to approximately 20 mm, such as approximately 5 mm to approximately 10 mm, etc. In some examples, the window body 321 and the lenses 325 may be manufactured separately and joined together. For example, the flat surface of each lens 325 may be joined to a flat top surface 323. In such examples, the lenses 325 may be made of the same or different material as the window body 321. In one example, the lenses 325 may be formed from quartz or fused quartz (amorphous quartz). In some other examples, the lenses 325 may be machined into the surface of the window body 321.

[0051] During operation, the window assembly 320 is cooled by convection using a forced airflow directed generally parallel to the plane of the window assembly 320, across the upper surface 323 of the window body 321 and across the outer surface 326 of each lens 325. The airflow may be directed between the lamp 190 and the window assembly 320.

[0052] When the window assembly 320 is configured for use with a vacuum pressure RTP, the thickness T2 measured between the upper surface 323 and the lower surface 324 can be approximately 20 mm to approximately 25 mm. In one example, the distance between the substrate 112 and the lamp 190 can be approximately 40 mm to approximately 45 mm, which can be greater than the corresponding distance for an atmospheric pressure RTP where a thinner window may be used. Thus, when a flat window is used in a vacuum pressure RTP, a loss of zone radiation control from ray diffusion can occur, which is more noticeable over the longer distances associated with the vacuum pressure RTP. Advantageously, compared to a flat window, the window assembly 320 provides improved directivity and / or focusing of radiation (e.g., rays) returning towards the axis 337 perpendicular to the plane of the window assembly 320, and therefore provides improved zone radiation control and temperature control uniformity.

[0053] Figure 4 is an enlarged side cross-sectional view showing another exemplary window assembly 420 that may be used in the heat treatment chamber 110 of Figure 3A. The window assembly 420 is similar to the window assembly 320 of Figures 3A–3B, except that it has lenses on both the top and bottom surfaces of the window body 321. In addition to the upward-facing lens 325, the window body 321 in Figure 4 further includes a plurality of lenses 427 extending downward from the bottom surface 324. In Figure 4, the bottom surface 324 is shown by at least a partially dashed line. The lenses 427 may be constructed and arranged similarly to the lens 325. The lenses 427 are spaced laterally apart from each other in a direction parallel to the plane of the window assembly 420. Each lens 427 also aligns with the corresponding ramp 190 and the corresponding lens 325 along an axis 337 perpendicular to the plane of the window assembly 420.

[0054] As shown in the figure, each lens 427 has a convex shape that is thicker in the center than at the edges in order to change the direction of wide-angle radiation and return it toward the axis 337. For example, the thickness T3 measured between the outer surface 326 of each lens 325 and the outer surface 429 of each lens 427 is greater than the thickness T4 measured between the upper surface 323 and the lower surface 324. As a result, the outer surface 429 of each lens 427 is closer to the substrate 112 than the lower surface 324. During processing using the window assembly 420 having lenses disposed on both the upper surface 323 and the lower surface 324, a larger portion of the radiation from the lamp 190 may be aligned parallel to the axis 337 compared to processing using the window assembly 320 having lenses disposed on only one surface of the window body 321. For example, each set of lenses partially changes the direction of radiation and returns it toward the axis 337, thereby the additive effect of the upper and lower lenses is greater than the effect of either the upper or lower lens alone. In some other examples, a window assembly may have a lens only on the bottom surface and no lens on the top surface.

[0055] The foregoing applies to embodiments of the present disclosure, but other and further embodiments of the present disclosure can be devised without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the following claims.

Claims

1. A window assembly for a heat treatment chamber applicable for semiconductor processing, wherein the window assembly is The upper window and The lower window and A plurality of linear reflectors disposed between the upper window and the lower window, wherein the plurality of linear reflectors extend in the longitudinal direction parallel to each other and parallel to the plane of the window assembly, A pressure control region defined between the upper window, the lower window, and the sides of each linear reflector. A window assembly equipped with the following features.

2. The window assembly according to claim 1, wherein the pressure control region comprises a plurality of interconnected sub-regions, the plurality of sub-regions being separated laterally from each other in a direction parallel to the plane of the window assembly and connected to each other by corresponding flow paths disposed in the bodies of each linear reflector.

3. The window assembly according to claim 1, wherein cooling channels are formed in the body of each linear reflector.

4. The window assembly according to claim 3, wherein the cooling channel forms a continuous cooling path extending through the plurality of linear reflectors.

5. The window assembly according to claim 1, wherein each linear reflector extends over substantially the entire length of the window assembly.

6. The window assembly according to claim 1, wherein at least one of the plurality of linear reflectors extends over only a portion of the length of the window assembly.

7. The window assembly according to claim 1, wherein the sides of each linear reflector are parallel to each other and perpendicular to the plane of the window assembly.

8. The window assembly according to claim 1, wherein the side surfaces of each linear reflector are tapered.

9. The window assembly according to claim 1, wherein the side surfaces of each linear reflector are double-tapered.

10. A heat treatment chamber applicable for semiconductor processing, One or more side walls surround the processing area, A substrate support within the processing region, wherein the substrate support has a substrate support surface, A window assembly disposed above one or more side walls, wherein the window assembly is The upper window and The lower window and A plurality of linear reflectors disposed between the upper window and the lower window, wherein the plurality of linear reflectors extend in the longitudinal direction parallel to each other and parallel to the plane of the window assembly, A pressure control region defined between the upper window, the lower window, and the sides of each linear reflector. A window assembly comprising, A lamp head disposed above the aforementioned window assembly and A heat treatment chamber equipped with the following features.

11. The heat treatment chamber according to claim 10, wherein the lamp head includes a plurality of linear lamps, and the plurality of linear reflectors and the plurality of linear lamps are arranged alternately in a direction parallel to the plane of the window assembly.

12. The heat treatment chamber according to claim 10, wherein the plurality of linear reflectors are sized to generally conform to the shape of the substrate support.

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