TW201501207A - Light pipe window structure for thermal chamber applications and processes - Google Patents

Abstract

A processing chamber is described. The processing chamber includes a chamber having an interior volume, a light pipe window structure coupled to the chamber, the light pipe window structure having a first transparent plate disposed within the interior volume of the chamber, and a radiant heat source coupled to a second transparent plate of the light pipe window structure in a position outside of the interior volume of the chamber, wherein the light pipe window structure includes a plurality of light pipe structures disposed between the first transparent plate and the second transparent plate.

Description

Light pipe window structure for thermal chamber applications and processes

Apparatus and methods for semiconductor processing are disclosed herein. More particularly, the embodiments disclosed herein relate to a light pipe structure for heat treatment of a semiconductor substrate.

Heat treatment is commonly practiced in the semiconductor industry. Semiconductor substrates are subjected to heat treatment in a number of variations, including deposition of gate source, drain and channel structures, doping, activation and annealing, deuteration, crystallization, oxidation, and the like. After several years, heat treatment techniques have evolved from simple oven baking to various forms of incremental rapid thermal processing (RTP), spike annealing, and other heat treatments.

As the critical dimensions of semiconductor component features continue to shrink, more severely limited thermal budgets during thermal processing are required. Many of the foregoing thermal processes are heated by a lamp in the form of a lamp head, wherein the lamp head is comprised of a plurality of light sources positioned to direct radiant energy toward the substrate. However, high intensity lamps that are utilized in the base create high temperatures within the material of the base. This temperature must be controlled for many processes to cool the substrate. For example, during the RTP, from the light The thermal radiation is generally used to rapidly heat the substrate in a controlled environment to a maximum temperature of up to about 1350 °C. This maximum temperature is maintained for a specific time ranging from less than one second to several minutes (depending on the process). The substrate was then cooled to room temperature for further processing. In order to be able to cool to room temperature, the lamp head must be cooled. However, due to many factors, the control of the temperature of the lamp cap is difficult to achieve. Furthermore, in conventional bases, the illumination pattern of the source is sometimes irregular, which can result in irregular substrate heating.

There is a need for a method and apparatus that can improve the temperature control of a lamp cap in a thermal process chamber.

The embodiments disclosed herein relate to a light pipe structure for heat treatment of a semiconductor substrate.

In one embodiment, a light pipe window structure for use in a thermal processing chamber is described. The light pipe window structure comprises: a first transparent plate; a second transparent plate; a plurality of light pipe structures, wherein the plurality of light pipe structures are disposed between the first transparent plate and the second transparent plate and are bonded And to the first transparent plate and the second transparent plate, each of the light pipe structures of the plurality of light pipe structures comprises a transparent material and has a longitudinal axis, and the longitudinal axis is disposed with one of the first or second transparent plates The plane is substantially orthogonal; and a housing that engages the first transparent plate and the second transparent plate and surrounds the plurality of light pipe structures.

In another embodiment, a light pipe window structure for use in a thermal processing chamber is described. The light pipe window structure comprises: a first transparent plate; a second transparent plate, the second transparent plate is disposed in a substantially parallel relationship with the first transparent plate; and a plurality of light pipe structures, the plurality of light Tube structure is set in the Between the first transparent plate and the second transparent plate, wherein the thickness of the first transparent plate is thicker than the thickness of the second transparent plate.

In another embodiment, a substrate processing chamber is provided. The process chamber includes: a chamber having an internal space; a light pipe window structure coupled to the chamber, the light pipe window structure having a first transparent plate, the first a transparent plate is in communication with the inner space of the chamber; and a radiant heat source coupled to a second transparent plate of the light pipe window structure at a position outside the inner space of the chamber, wherein the radiant heat source The light pipe window structure includes a plurality of light pipe structures disposed between the first transparent plate and the second transparent plate.

100‧‧‧Processing chamber

101‧‧‧Light pipe window structure

102‧‧‧Substrate support

104‧‧‧ Chamber body

105‧‧‧Light head assembly

106‧‧‧radiation heat source

108‧‧‧ side wall

110‧‧‧ bottom

112‧‧‧ top

114‧‧‧First transparent board

115‧‧‧Second transparent board

116‧‧‧ proximity sensor

117‧‧‧temperature sensor

118‧‧‧stator assembly

119‧‧‧Rotor

120‧‧‧Internal space

121‧‧‧Support ring

122‧‧‧Actuator assembly

123‧‧‧Shell

124‧‧‧ Controller

126‧‧‧ memory

127‧‧‧ tube

128‧‧‧Support circuit

130‧‧‧CPU

132‧‧‧ Guide bolt

134‧‧‧Flange

138‧‧‧Motor

140‧‧‧Substrate

144‧‧‧lifting pin

148‧‧‧Substrate access

158‧‧‧ nuts

159‧‧‧Shell

160‧‧‧Light pipe structure

162‧‧‧Energy source

164‧‧‧Control system

168‧‧‧ drive coil assembly

170‧‧‧suspension coil assembly

180‧‧‧cooling block

181A‧‧‧ entrance

181B‧‧‧Export

182‧‧‧ coolant source

184‧‧‧ coolant passage

200‧‧‧ sealed interior space

205‧‧‧ Input 埠

207‧‧‧ gap

210‧‧‧ Output埠

215‧‧‧ coolant source

220‧‧‧ gap

300‧‧‧Power source

305A‧‧‧Outside

305B‧‧‧ Inner District

310‧‧‧Seal

315‧‧‧ coolant source

400‧‧‧Processing chamber

402‧‧‧ Back side

404‧‧‧Substrate support

405‧‧‧lifting pin

406‧‧‧Upper dome

408‧‧‧ base ring

410‧‧‧Flange

412‧‧‧Process area

414‧‧‧ flushing area

415‧‧‧ center pole

416‧‧‧ recess

418‧‧‧Seal

420‧‧‧ clamping ring

422‧‧‧ Round cover

424‧‧‧linear components

426‧‧‧Optical pyrometer

428‧‧‧ component side

430‧‧‧reflector

432‧‧‧埠

434‧‧‧ channel

436‧‧‧Process gas source

438‧‧‧Process gas inlet

440‧‧‧Flow path

442‧‧‧Flow path

444‧‧‧ gas export

446‧‧‧vacuum pump

448‧‧‧ flushing gas source

450‧‧‧ flushing gas inlet

452‧‧‧Flow path

454‧‧‧Flow path

460‧‧‧ Measure light pipe

462‧‧‧ sensor

464‧‧‧Fiber optic cable

500‧‧‧Light pipe window structure

505‧‧‧ first board

510‧‧‧ ring block

515‧‧‧ central structure

520‧‧‧ second board

525‧‧‧ surface

600‧‧‧Light pipe window structure

610‧‧‧ ring block

612‧‧‧Strips

The more specific description of the present invention may be understood in detail by reference to the embodiments, which are briefly described in the foregoing. It is to be understood, however, that the appended claims

Figure 1 is a simplified perspective view of a process chamber having an embodiment of a light pipe window structure.

2A-2C is a view showing an embodiment of the light pipe window structure of Fig. 1.

Figure 3 is a side cross-sectional view of a portion of the process chamber of Figure 1 showing the light pipe window structure and the lamp cap assembly.

Figure 4 is a schematic cross-sectional view of the process chamber showing another embodiment of the light pipe window structure.

Figure 5 is a schematic illustration of a portion of another embodiment of a light pipe window structure.

Figure 6 is a schematic illustration of a portion of another embodiment of a light pipe window structure.

To promote understanding, the same element symbols are used where possible to indicate the same elements that are common to the drawings. It is contemplated that elements and features of an embodiment may be beneficially incorporated into other embodiments without particular detail.

Embodiments disclosed herein relate to use in thermal processing chambers (such as deposition chambers, etching chambers, annealing chambers, implantation chambers, chambers for LED formation, and other processing chambers) Light pipe window structure. The light pipe window structure can be used in a process chamber available from Applied Materials, Inc. of Santa Clara, Calif., and can also be used in process chambers that are also available from other manufacturers.

1 is a simplified schematic diagram of a rapid thermal processing chamber (RTP chamber) 100 having a light pipe window structure 101 in accordance with an embodiment. The process chamber 100 includes a non-contact or magnetically suspended substrate support 102 and a chamber body 104 having sidewalls 108, a bottom portion 110 and a top portion 112 that define an interior space 120. The sidewalls 108 typically include a substrate pick-up 148 to facilitate entry and exit of the substrate 140 (Fig. 1 shows a portion of the substrate pick-up 148). The pick-up 148 can be coupled to a transfer chamber (not shown) or a load lock chamber (not shown) and can be selectively sealed with a valve, such as a slit valve (not shown). In an embodiment, the substrate support 102 is annular and sized to receive the cap assembly 105 in the inner diameter of the substrate support 102. Lamp assembly 105 includes a light pipe window structure 101 and a radiant heat source 106.

The substrate support 102 is adapted to magnetically float and rotate within the interior space 120. The substrate support 102 can be vertically raised and lowered during processing, and can also be raised or lowered without rotation prior to, during, or after processing. Such magnetic suspension and/or magnetic rotation. Particle generation due to the disappearance or reduction of component rotation and/or contact between the relatively moving components, which typically requires raising/lowering and/or rotating the substrate support, can be avoided or minimized.

The stator assembly 118 surrounds the sidewall 108 of the chamber body 104 and is coupled to one or more actuator assemblies 122 that control the stator assembly 118 along the exterior of the chamber body 104 the height of. In an embodiment (not shown), the process chamber 100 includes three actuator assemblies 122 that are radially disposed about the chamber body (e.g., around the chamber body 104 at an angle of about 120 degrees). The stator assembly 118 is magnetically coupled to the substrate support 102 disposed within the interior space 120 of the chamber body 104. The substrate support 102 can include or include a magnetic portion that acts as the rotor 119, thus creating a magnetic bearing assembly to raise and lower and/or rotate the substrate support 102. A support ring 121 is coupled to the rotor 119 to support a peripheral edge of the substrate 140. The size of the support ring 121 allows the support ring 121 to stably support the substrate 140 while minimizing the portion of the back side of the substrate 140 from the energy radiated by the radiant heat source 106. The stator assembly 118 includes a drive coil assembly 168 that is stacked on the suspension coil assembly 170. The drive coil assembly 168 is adapted to rotate and/or raise/lower the substrate support 102, and the suspension coil assembly 170 can be adapted to passively center the substrate support 102 within the process chamber 100. Alternatively, by having a single coil assembly The stator is used to perform the rotation and centering functions.

In an embodiment, each actuator assembly 122 generally includes precision guide bolts 132 that are coupled between two flanges 134 that extend from sidewalls 108 of the chamber body 104. The guide bolt 132 has a nut 158 that will travel axially along the guide bolt 132 as the bolt rotates. The coupling 136 is placed between the stator assembly 118 and the nut 158 and couples the nut 158 to the stator assembly 118 such that when the guide bolt 132 is rotated, the coupling 136 will follow the guide bolt 132 Move to control the height of the stator assembly 118 at the interface with the coupling 136. Thus, when the guide bolts 132 of the actuator assemblies of the actuator assemblies 122 are rotated to create relative displacement between the nuts 158 of the other actuator assemblies, the horizontal plane of the actuator assembly 118 would It changes with respect to the central axis of the chamber body 104.

In an embodiment, a motor 138, such as a stepper or servo motor, is coupled to the guide bolt 132 to provide a controllable rotation in response to a signal from the controller 124. Alternatively, other types of actuator assemblies 122 may be used to control the linear position of the stator assembly 118, such as pneumatic cylinders, hydraulic cylinders, ball screws, solenoids, linear actuators and cam followers, and the like.

An example of an RTP chamber that may be adapted to benefit from the embodiments disclosed herein is the VANTAGE ^® , VULCAN ^® , and CENTURA ^® processing systems available from Applied Materials, Inc., of Santa Clara, California. Although the apparatus is described as being used with a rapid thermal processing chamber and an epitaxial deposition chamber, the embodiments disclosed herein can be used in other processing systems and devices that use lamp heating elements for heating.

The light pipe window structure 101 includes light that can be heated and of various wavelengths (its The first transparent plate 114 and the second transparent plate 115 may be made of a material that transmits light in an infrared (IR) spectrum. The first transparent plate 114 and the second transparent plate 115 have a plurality of light pipe structures 160 disposed between the first transparent plate 114 and the second transparent plate 115. Each of the light pipe structures of the plurality of light pipe structures may include a cylindrical structure and the like. The first transparent plate and the second transparent plate may have a substantially uniform thickness and may have a solid cross section. For example, the first transparent plate 114 and the second transparent plate 115 may have no perforations. The light pipe structure 160 is provided as a light pipe through which photons of a plurality of energy sources 162 from the radiant heat source 106 pass to heat the substrate 140 during processing. In an embodiment, each of the light pipe structures 160 may have total internal reflection (TIR) properties under normal conditions.

The process chamber 100 also includes one or more proximity sensors 116 that are generally adapted to detect the substrate support 102 within the interior space 120 of the chamber body 104 ( Or the height of the substrate 140). The sensor 116 can be coupled to the chamber body 104 and/or other portions of the process chamber 100 and is adapted to provide an indication between the substrate support 102 and the top 112 and/or bottom 110 of the chamber body 104. The output of the distance can also detect misalignment of the substrate support 102 and/or the substrate 140.

The base assembly 105 can include both a radiant heat source 106 and a light pipe window structure 101. The light pipe window structure 101 can include a housing 159 that at least partially surrounds the light pipe window structure 101. The radiant heat source 106 includes a light assembly formed by a housing 123 that includes a plurality of closely spaced tubes 127. The tubes 127 can be formed in a honeycomb light tube configuration. Each tube 127 can include a reflector and a high intensity energy source 162, which can be a lamp, a laser, A laser diode, a light emitting diode, an IR emitter, or a combination of the above. Each tube 127 can be substantially axially aligned with the respective light pipe structure 160 of the light pipe window structure 101. The light pipe structure 160 is used to transfer energy radiated by the respective energy sources 162 toward the substrate 140. In one embodiment, the cap assembly 105 provides sufficient radiant energy to heat treat the substrate 140, such as annealing a layer of tantalum disposed on the substrate 140. The base assembly 105 can further include an annular region in which the voltage supplied by the controller 124 to the plurality of energy sources 162 can be varied to increase the radial distribution of energy from the base assembly 105. Dynamic control of the heating of the substrate 140 may be affected by the one or more temperature sensors 117 (described in more detail below), wherein the one or more temperature sensors 117 are measured throughout the substrate 140 temperature.

In one embodiment, both the first transparent plate 114 and the second transparent plate 115 are made of a quartz material (ie, amorphous ceria), although other materials that transmit energy (such as wavelengths in the infrared spectrum) can be used ( Such as glass, sapphire, aluminosilicate and glass). The first transparent plate 114 and the second transparent plate 115 may be made of a clear molten quartz material having a low inclusion tolerance. As used herein, the term "transparent" refers to a substance that does not significantly alter the direction or intensity of the wavelength range of selected electromagnetic radiation within the volume of the substance. In one example, the average direction change in the wavelength range of the selected electromagnetic radiation is less than a few degrees and the average intensity reduction is less than about 70%.

The first transparent plate 114 includes a plurality of lift pins 144 coupled to the upper surface of the first transparent plate 114 to facilitate transfer of the substrate into or out of the process chamber 100. For example, the stator assembly 118 can be actuated to move downward, which causes the rotor 119 to move toward the base assembly 105. Any direction used here (the Such as "down" or "down" and "up" or "up" are based on the orientation of the chamber as shown and may not be actually true.

The support ring 121 of the support substrate 140 moves with the rotor 119. At a desired height, the substrate 140 contacts the lift pins 144 disposed on the first through plate 114. The downward movement of the rotor 119 (and the support ring 121) continues until the rotor 119 surrounds the outer casing 159 of the base assembly 105. The downward movement of the rotor 119 (and the support ring 121) continues until the support ring 121 is spaced a distance from the substrate 140 that is stably supported on the lift pins 144. The height of the lift pins 144 can be selected to support and align the substrate 140 along a plane that is coplanar with the plane of the substrate 148 or adjacent to the plane of the substrate 148. The plurality of lift pins 144 can be positioned between the light pipe structures 160 and radially spaced apart from each other to facilitate end effector (not shown) from picking up the turns 148 through the substrate. Alternatively, the end effector and/or robot can be moved horizontally and vertically to facilitate transfer of the substrate 140. Each of the lift pins 144 of the plurality of lift pins 144 can be positioned between the light pipe structures 160 to minimize absorption of energy from the radiant heat source 106. Each of the lift pins 144 of the plurality of lift pins 144 may be made of the same material as the first transparent plate 114, such as a quartz material.

The process chamber 100 also includes a controller 124 that generally includes a central processing unit (CPU) 130, a support circuit 128, and a memory 126. The CPU 130 can be one of any form of computer processor and secondary processor that can be used in an industrial device to control various actions. The memory 126 or computer readable medium can be one or more readily available memories, such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form. Digital storage, either local or remote, and typically coupled Received to the CPU 130. Support circuit 128 is coupled to CPU 130 to support controller 124 in a conventional manner. These circuits include caches, power supplies, clock circuits, input/output circuits, subsystems, and the like.

The ambience control system 164 is also coupled to the interior space 120 of the chamber body 104. The ambience control system 164 generally includes a throttle valve and a vacuum pump to control the chamber pressure. The ambience control system 164 can additionally include a gas source to provide a process or other gas to the interior space 120. The atmosphere control system 164 can also be adapted to deliver process gases for the thermal deposition process. The interior space 120 is substantially maintained at vacuum pressure during processing. Aspects of the present disclosure include embodiments in which the cap assembly 105 is at least partially disposed in the interior space 120 (and subjected to negative pressure in the interior space 120), while a portion of the cap assembly 105 is positioned outside of the interior space 120 (ie, In the outside atmosphere). This configuration provides efficient energy transfer to the substrate 140 while improving the ability to control the temperature of the radiant heat source 106.

The process chamber 100 also includes one or more temperature sensors 117 adapted to sense the temperature of the substrate 140 before, during, and after processing. In the embodiment illustrated in FIG. 1, the temperature sensors 117 are disposed through the top portion 112, although other locations within the chamber body 104 and surrounding the chamber body 104 may be utilized. The temperature sensors 117 can be optical pyrometers, such as pyrometers with fiber optic probes. The sensors 117 can be adapted to be coupled to the top portion 112 in a configuration that senses the full diameter of the substrate or a portion of the substrate. The sensors 117 can include a pattern that defines a sensing region that is substantially equal to the diameter of the substrate or a sensing region that is substantially equal to the radius of the substrate. For example, a plurality of sensors 117 can be coupled to the top in a radial or linear configuration. Portion 112 to create a sensing region across the radius or diameter of the substrate. In an embodiment (not shown), a plurality of sensors 117 can be disposed in a line that extends radially from a center of the top portion 112 to a surrounding portion of the top portion 112. In this manner, the radius of the substrate can be monitored by the sensors 117, which can enable sensing of the radius of the substrate during rotation.

The process chamber 100 also includes a cooling block 180 that is adjacent, coupled to, or formed in the top portion 112. In general, the cooling block 180 is spaced apart from the base assembly 105 and faces the base assembly 105. Cooling block 180 includes one or more coolant passages 184 that are coupled to inlet 181A and outlet 181B. The cooling block 180 can be made of a process resistant material such as stainless steel, aluminum, polymer, or ceramic material. The coolant passages 184 may comprise a spiral pattern, a rectangular pattern, a circular pattern, or a combination of the above, and the channels 184 may be integrally formed within the cooling block 180, such as by casting a cooling block 180 and/or from two or More components are used to make the cooling block 180 and join the components. Additionally or alternatively, the coolant passage 184 can be drilled into the cooling block 180. The inlet 181A and the outlet 181B can be coupled to the coolant source 182 by a valve and appropriate piping, and the coolant source 182 and the controller 124 communicate to promote pressure and/or flow of fluid disposed in the coolant source 182. control. The fluid can be water, ethylene glycol, nitrogen (N ₂ ), helium (He), or other fluids as a heat exchange medium.

As described herein, the process chamber 100 is adapted to receive a substrate in a "face-up" orientation wherein the deposit receiving side or face of the substrate is oriented toward the cooling block 180 and the substrate The back side faces the base assembly 105. The "face up" orientation allows the energy from the lamp cap assembly 105 to be absorbed more quickly by the substrate 140 because the back side of the substrate is less reflective than the face of the substrate.

2A-2C is a various view showing an embodiment of a light pipe window structure 101 that can be used in the process chamber 100 of FIG. Figure 2A is a partial exploded view of the light pipe window structure 101. Fig. 2B is a cross-sectional view of the light pipe window structure 101 taken along line 2B-2B of Fig. 2A. Figure 2C is a cross-sectional view of the light pipe window structure 101 along line 2C-2C of Figure 2B. The lift pins 144 shown in Fig. 1 are not shown in the second A-2C diagram.

The light pipe window structure 101 includes a casing 159, a first transparent plate 114, a second transparent plate 115, and a light pipe structure 160, and the light pipe structure 160 is sandwiched between the first transparent plate 114 and the second transparent plate 115. As shown, the first transparent plate 114 can be a solid, flat member that is coupled to the outer casing. The second transparent plate 115 may be a solid flat member like the first transparent plate 114. Both the first transparent plate 114 and the second transparent plate 115 may be made of an optically transparent material such as quartz or sapphire. Likewise, the outer casing 159 can be made of an optically transparent material such as quartz. As used herein, the term "optically transparent" is the ability of a material to transmit radiation (eg, light waves or other wavelengths used to heat other objects, and especially wavelengths in the visible spectrum, such as non-visible wavelengths in the infrared (IR) spectrum). . Both the first transparent plate 114 and the second transparent plate 115 can be joined by a diffusion soldering process or other suitable bonding method. The individual light pipe structures 160 of the light pipe structures 160 may be solid, such as rods made of an optically transparent material such as the same material as the first transparent plate 114 and the second transparent plate 115 (ie, fused silica or sapphire). . Alternatively, at least a portion of the light pipe structure 160 can be a hollow tube made of an optically transparent material such as quartz or sapphire.

The cross section of the light pipe structure 160 may include a circle, a rectangle, a triangle, a diamond, or a combination thereof, or other polygonal and/or irregular shapes. In the plane In the figures, the individual light pipe structures 160 of the light pipe structures 160 may include substantially parallel edges (as shown in FIG. 2C), or gathered or offset edges such that the conical shape is formed in a plan view.

The method of forming the light pipe window structure 101 includes cutting a block of optically transparent material to produce the light pipe structures 160. The plates of optically transparent material can be accurately sawed at a particular angle and depth to produce the light pipe structures 160 having a polygonal shape in cross section as discussed above. If a wire saw is used, the wire can be manipulated to lie in a plane that is parallel to the major surface of the panel. A kerf can be used to form a void around the light pipe structures 160. Forming the light pipe structures 160 into a particular depth system provides one of the first transparent plate 114 or the second transparent plate 115 to be integrated into the light pipe structures. Other transparent plates may be joined to the light pipe structures 160 by a bonding process such as ceramic soldering techniques, sealing glass bonding, diffusion soldering processes, or other suitable bonding methods. When rods or hollow tubes of optically transparent material are used as the light pipe structures 160, the light pipe structures 160 may be joined by a bonding process (such as ceramic soldering techniques, sealing glass bonding, diffusion soldering processes, or other suitable bonding). The method) is bonded to one or both of the first transparent plate 114 and the second transparent plate 115. The light pipe structures 160 are shown as having a circular cross-section, but in some embodiments, at least a portion of the light pipe structures 160 may have a polygonal cross-sectional shape. In one embodiment, the closely packed configuration of the light pipe structures 160 is sized and spaced to substantially align with the individual tubes 127 (shown in FIG. 1) of the tubes 127 of the radiant heat source 160. Aligned. However, some misalignment between the tubes 127 and the light pipe structures 160 can also be used to provide high power strength and good spatial resolution. Again, as mentioned above, in some biography In the base of the lamp, the pattern of the picture is irregular, which may be caused by manufacturing changes in the lamp. However, in some embodiments, the light pipe structures 160 of the light pipe window structure 101 can also produce a smoother pattern at the target plane (ie, the surface of the heated substrate), thus causing the base assembly 105 to It is not affected by manufacturing variations between the lamp and the lamp.

As shown in FIG. 2B, each of the light pipe structures 160 of the light pipe structures 160 includes a longitudinal axis A that is substantially perpendicular to a plane of one or both of the first transparent plate 114 and the second transparent plate 115. . When the first transparent plate 114 and the second transparent plate 115 are coupled to the outer casing 159, the sealed inner space 200 can be received in the inner side wall of the outer casing 159, and the light pipe structure 160, the first transparent plate 114, in the gap 207 between the second transparent plate. In some embodiments, the housing 159 can include an input port 205 and an output port 210. The input port 205 and the output port 210 can be coupled to a coolant source 215 that circulates fluid through the sealed interior space 200 and the gap 207 between the tube structures 160 for cooling the light pipe window structure 101. The fluid can be water, ethylene glycol, nitrogen (N ₂ ), helium (He), or other fluids as a heat exchange medium. A small gap 220 (as shown in FIG. 2C) provides flow of fluid around the light pipe structures 160 to facilitate cooling of the individual light pipe structures 160 of the light pipe structures 160. Additionally or alternatively, in order for the cooling fluid to flow through the input port 205 and the output port 210, one or both of the input port 205 and the output port 210 may be coupled to a vacuum pump (as shown in FIG. 2B) for Lower pressure is applied to the sealed interior space 200 and the gaps 207 and gaps 220 between the tube structures 160. A vacuum pump can be used to reduce the pressure in the sealed interior space 200 and void 207, thereby reducing the pressure drop between the interior space 120 and the sealed interior space 200.

Referring again to FIG. 1, the first transparent plate 114 can be exposed to a low pressure in the interior space 120 of the chamber body 104. The pressure at which the first transparent plate 114 is exposed may be a vacuum of 80 Torr, or higher (such as from about 5 Torr to about 10 Torr). Bonding the light pipe structure 160 to both the first transparent plate 114 and the second transparent plate 115 provides additional structural rigidity to the first transparent plate 114, thus allowing the first transparent plate 114 to withstand pressure differentials without failure . In one embodiment, as shown in FIG. 2B, the first transparent plate 114 is thicker than the second transparent plate 115 in order to endure the low pressure in the interior space 120. In an embodiment, the first transparent plate 114 may have a thickness of between about 7 mm and about 5 mm. In some embodiments, the first transparent plate 114 is about twice as thick as the second transparent plate 115. The light pipe structure 160 can include a major dimension that can be a diameter and substantially equal to the major dimension (e.g., diameter) of the tube 127 of the radiant heat source 106. In an embodiment, the length of the light pipe structure 160 can be from about 10 mm to about 80 mm.

Fig. 3 is a side cross-sectional view showing a part of the process chamber 100 of Fig. 1. In this figure, the substrate 140 is supported by the lift pins 144 and the support ring 121. The location of the substrate 140 can be used to initiate a thermal process on the substrate 140 after the substrate is transferred to the process chamber 100, wherein the substrate 140 can be heated by the radiant heat source 106 in the process chamber 100. If the support ring 121 is hotter than the substrate 140, the open loop heating of the radiant heat source 106 can be used to raise the temperature of the substrate (supported by the support pins 144) to approach the temperature of the support ring 121, and to avoid heat in the substrate 140. stress. When the substrate 140 is sufficiently heated, the substrate 140 can be transferred to the support ring and raised away from the support pins 144 to allow for rotation of the substrate 140 during processing.

To heat the substrate 140, the energy source 162 of the radiant heat source 106 is provided with power from the power source 300. Power source 300 can be a multi-zone power source that provides energy to one or more groups of energy sources 162 of radiant heat source 106. For example, the first or outer zone 305A can include an outer set of energy sources 162 or a secondary set of energy sources 162 located on the periphery of the housing 123. Similarly, the second or inner zone 305B can include a group or subgroup of energy sources 162 located within the outer zone 305A. In one embodiment, the energy sources 162 can be separated into approximately ten concentric regions that are individually controlled in a closed loop heating mechanism.

When the substrate 140 is heated, the cap assembly 105 (especially the radiant heat source 106) experiences an elevated temperature, and the temperature of the radiant heat source 106 can be suitably controlled in accordance with the embodiments disclosed herein. For example, at least a portion of the base assembly 105 is disposed outside of the interior space 120 of the process chamber 100 (ie, ambient pressure), which provides temperature control of the elevated radiant heat source 106. The improved temperature control of the radiant heat source 106 promotes the efficiency of the larger process chamber 100.

In an embodiment, radiant heat source 106 is coupled to coolant source 315 to facilitate cooling of housing 123 of elevated radiant heat source 106. The coolant source 315 may be a coolant such as water, ethylene glycol, nitrogen (N _2), helium (H), or other fluid as the heat exchange medium. Coolant may be flowed through the housing 123 and between the energy sources 162 of the radiant heat source 106.

FIG. 4 shows a schematic cross-sectional view of a process chamber 400 having another embodiment of a light pipe window structure 101 disposed on the process chamber 400. Process chamber 400 can be used to process one or more substrates, including deposition of material on the upper surface of substrate 140. Although not detailed here It is discussed that the deposited material may include gallium arsenide, gallium nitride, or aluminum gallium nitride. The process chamber 400 can include a base assembly 105 as disclosed herein that includes an array of energy sources 162 for heating (except for other components) with the back side 402 of the substrate support 404 disposed in the process chamber Inside the room 400. The substrate support 404 can be a dish-shaped substrate support 404 (as shown), or can be an annular substrate support similar to that shown in Figures 1 and 3, the substrate support 404 from the substrate The edge 404 supports the substrate to promote thermal radiation that the substrate can be exposed to the light pipe window structure 101. In FIG. 4, elements similar to those described in FIGS. 1-3 are used with similar element symbols, and unless otherwise specified, will operate similarly and will not be repeated for the sake of brevity. Additionally, embodiments of the light pipe window structure 101 depicted in FIG. 4 can be used in the process chamber 100 of FIGS. 1 and 3, and vice versa.

The substrate support 404 is disposed in the process chamber 400 between the upper dome 406 and the first transparent plate 114 of the light pipe window structure 101. The upper dome 406, the upper surface of the first transparent plate 114, and the base ring 408 (disposed between the upper dome 406 and the mounting flange 410 of the light pipe window structure 101) substantially define the interior region of the custom process chamber 400 . The substrate support 404 substantially separates the interior space of the process chamber 400 into a process region above the substrate and a rinse region 414 below the substrate support 404. The substrate support 404 can be rotated by the center rod 415 during processing to minimize the effects of heat and process gas flow space irregularities within the process chamber 400, and thus promote uniform processing of the substrate 140. The substrate support 404 is supported by a central rod 415 that can move the substrate 140 in a vertical direction (as indicated by the arrows) during the substrate transfer process and in some cases during processing of the substrate 140. The substrate support 404 can be coated or coated with tantalum carbide Graphite coated with tantalum carbide is formed to absorb the radiant energy from the energy source 162 and conduct the radiant energy to the substrate 140. A plurality of lift pins 405 can be disposed in the process chamber 400 at a position outward of the center rod 415. The lift pin 405 can be coupled to an actuator (not shown) to vertically move the lift pin 405 within the process chamber 400 relative to the substrate support 404 and independently of the substrate support 404. Substrate 140 can be transferred into processing chamber 400 via a loading cassette (not shown) and positioned on substrate support 404. Figure 4 shows the substrate support 404 in a raised processing position, but the substrate support 404 can be moved vertically by an actuator (not shown) to a loading position below the processing position to allow the lift pin 405 to contact Substrate 140 and separate substrate 140 from substrate support 404. Next, a robot (not shown) can enter the process chamber 400 via the load port to pick up and remove the substrate 140 from the process chamber 400.

Generally, the upper dome 406 and the first transparent plate 114 are made of an optically transparent material such as the quartz or sapphire material discussed above. In this embodiment, the first transparent plate 114 of the light pipe window structure 101 includes a recess 416 that provides additional structural rigidity to the light pipe window structure 101. The recess 416 provides a concave or dome shape to the light pipe window structure 101 and may enable a thinner cross-sectional dimension of one or both of the first transparent plate 114 and the second transparent plate 115 to operate simultaneously Provides structural rigidity at lower pressures.

In one embodiment, the light pipe window structure 101 having the flat first transparent plate 114 may have a thickness of about 40 mm and a first transparent plate 114 having a concave shape (for example, the recess 416 shown in FIG. 4). The thickness of the light pipe window structure 101 can be about 35 mm. In some embodiments, the first transparent plate 114 is about twice as thick as the second transparent plate 115. At least the first transparent plate 114 of the light pipe window structure 101 can be coupled to the mounting flange 410 that can be coupled between the side wall 108 and the base ring 408. A seal 418, such as an O-ring, can be used to seal the mounting flange 410 to the sidewall 108 and the base ring 408. The upper dome 406 can be coupled to the base ring 408 and the clamp ring 420 with a seal 418 disposed between the upper dome and the base ring 408 and the clamp ring 420 for sealing.

Energy source 162 can be configured to heat substrate 140 to a temperature in the range of from about 200 °C to about 1600 °C. Each energy source 162 can be coupled to a power source 300 and a controller (as shown in FIG. 3). During or after processing, the base assembly 105 can be cooled by a coolant source 315 as shown and as illustrated in FIG. Alternatively or additionally, the cap assembly 105 can be cooled by convection cooling.

In an embodiment, at least a portion of one or both of the light pipe structure 160 and the energy source 162 may be angled toward a central axis of the process chamber 400. For example, the light pipe structure 160 and/or energy source 162 near the center rod 415 can be inclined inwardly from about 30 degrees to about 45 degrees relative to the plane of the first transparent plate 114 to direct radiant energy toward the center of the substrate support 404. Area (ie above the center rod 415). In an example, radiant energy from at least a portion of energy source 162 passes through transparent plate 114 at a non-orthogonal angle relative to the plane of transparent plate 114.

A circular cover 422 can optionally be disposed about the substrate support 404. The base ring 408 can also be surrounded by a cushion assembly 424. The mask 422 prevents or minimizes leakage of thermal/optical signals from the energy source 162 onto the component side 428 of the substrate 140 while providing a preheating zone for the process gas. The cover 422 can be CVD, SiC, sintered graphite coated with SiC, grown SiC, opaque quartz, coated quartz, or any similar suitable material that resists chemical collapse caused by the process and flushing gas. The cushion assembly 424 is sized to be disposed within or surrounded by the inner circumference of the base ring 408. The liner assembly 424 shields the processing space (i.e., the process region 412 from the rinse region 414) from contact with the metal walls of the process chamber 400. The metal wall reacts with the precursor and causes contamination in the processing space. Although the pad assembly 424 is shown as a single body, the pad assembly 424 can include one or more pads.

Process chamber 400 may also include an optical pyrometer 426 for temperature measurement/control on substrate 140. Temperature measurement of the optical pyrometer 426 can be performed on the component side 428 of the substrate 140. Thus, optical pyrometer 426 can only sense radiation from thermal substrate 140, with minimal background radiation from energy source 162 reaching optical pyrometer 426 directly. Reflector 430 can optionally be disposed outside of upper dome 406 to reflect light radiated from substrate 140 back onto substrate 140. The reflector 430 can be fixed to the clamp ring 420. The reflection member 430 may be made of a metal such as aluminum or stainless steel. The efficiency of reflection can be improved by providing a highly reflective coating such as gold (Au). Reflector 430 can have one or more turns 432 that are connected to a cooling source (not shown). The turns 432 can be connected to a channel 434 that is formed in or on the reflector 430. The passage 434 is configured to flow a fluid such as water or a gas such as helium, nitrogen, or other gas to cool the reflector 430.

In some embodiments, the light pipe window structure 101 can include one or more light pipes 460 that are formed in at least a portion of the light pipe window structure 101 or that are disposed through at least a portion of the light pipe window structure 101. Measuring light tube 460 can comprise sapphire or other transparent material as described herein. In one embodiment, the metering light pipe 460 is used to couple through the fiber optic cable 464 and a sensor 462, such as an optical pyrometer. The metrology light pipe 460 can have a diameter of from about 1 mm to about 2 mm and is positioned to be positioned between at least a portion of the light pipe structures 160. The metering light pipe 460 can have a length that extends from the surface of the first transparent plate 114 to the end of the metering light pipe 460 disposed below the housing 123 of the base assembly 105. Having one or more metric light pipes 460 (such as an array of metric light pipes 460) at a particular radial location or region directly below the first transparent plate 114 of the light pipe window structure 101 is allowed to be in close proximity to the substrate Temperature sensing at the location of the support 104 and/or the plane of the substrate 140. Measuring the light pipe 460 adjacent to the substrate support 104 and/or the substrate 140 allows for a smaller measurement position, which enables more precise temperature control.

Process gas supplied from process gas source 436 can be directed into process region 412 via process gas inlet 438 formed in the sidewalls of base ring 408. The process gas inlet 438 is configured to direct the process gas in a generally radially inward direction. During the film formation process, the substrate support 404 can be positioned at a processing location (where the processing location is adjacent and approximately the same height as the process gas inlet 438), while allowing the process gas to flow up the flow path 440 in a laminar flow mechanism The ground and the surrounding flow flow over the upper surface of the substrate 140. Process gas (along flow path 442) exits process region 412 via a gas outlet 444 disposed on a side of process chamber 400 opposite process gas inlet 438. Removal of the process gas via the gas outlet 444 can be facilitated by a vacuum pump 446 coupled to the gas outlet 444. Since the process gas inlet 438 and the gas outlet 444 are aligned with each other and disposed at about the same height, such a parallel configuration is associated with the upper dome 406. In time, a substantially flat uniform gas flow across the substrate 140 can be achieved. Rotation of the substrate 140 can be caused by the substrate support 404 to provide further radial uniformity.

The flushing gas may be supplied from the flushing gas source 448 to the flushing region 414 via an optional flushing gas inlet 450 formed in the sidewall of the base ring 408. The purge gas inlet 450 is disposed at a height below the process gas inlet 438. If a circular cover 422 or preheating ring (not shown) is used, a circular shield or preheat ring can be disposed between the process gas inlet 438 and the flushing gas inlet 450. In either case, the flushing gas inlet 450 is configured to direct the flushing gas in a generally radially inward direction. During the film formation process, the substrate support 404 can be positioned in a position such that the flushing gas flows downwardly and circumferentially along the flow path 452 across the back side 402 of the substrate support 404 in a laminar flow mechanism. Without being bound by any particular theory, the flow of the flushing purge gas may avoid or substantially prevent process gas from flowing into the flushing zone 414 or reducing process gas diffusion into the flushing zone 414 (i.e., the area below the substrate support 404). The flushing gas exits the flushing zone 414 (along the flow path 454) and is depleted out of the process chamber via the gas outlet 444, wherein the gas outlet 444 is disposed on the side of the process chamber 400 opposite the flushing gas inlet 450.

Similarly, during the flushing process, the substrate support 404 can be positioned in a raised position to allow the flushing gas to flow laterally across the back side 402 of the substrate support 404. It should be understood by those of ordinary skill in the art that the process gas inlet, flushing gas inlet and gas outlet shown in the figures are for illustrative purposes only, as the position, size, or number of gas inlets or outlets, etc., can be adjusted. To further promote the uniformity of the material on the substrate 140 product. Another option may be to provide flushing gas via process gas inlet 438. If desired, the purge gas inlet 450 can be configured to direct the purge gas in an upward direction to confine the process gas to the process region 412.

FIG. 5 is a perspective view of a portion of another embodiment of a light pipe window structure 500. The light pipe window structure 500 is shown with a first plate 505, which may be one of the first transparent plate 114 or the second transparent plate 115 as described above in relation to the light pipe window structure 101. The light pipe window structure 500 in this embodiment includes a plurality of light pipe structures in the form of loop blocks 510 and may include an optional central structure 515 as another light pipe structure. In an embodiment, the loop blocks 510 can be concentric. The loop blocks 510 can smooth the radiation from each of the energy sources 162 (as shown in Figures 1 and 4). The central structure 515 can have the form of a cylinder, a rod, or other polygonal shape. The opposing second panel 520 (where the second panel 520 of the portion of the fifth panel is shown) is joined to the surface 525 of the loop block 510 (and may include the topmost surface of the central structure 515 when the central structure 515 is included) To form a light pipe window structure 500. At least a portion of the loop blocks 510 can be a complete loop, or a plurality of arcuate segments forming a complete loop. The second plate 520 can be one of the first transparent plate 114 or the second transparent plate 115 as described above in relation to the light pipe window structure 101. The light pipe window structure 500 can be used in conjunction with the process chamber 100 or the process chamber 400 described in Figures 1, 3 and 4, respectively. When the light pipe window structure 500 is used with the process chamber 400, one or more of the center structure 515 and the innermost ring block 510 may not be needed in order to provide the center rod 415 and the lift pin 405 (eg, Pick up in Figure 4).

The loop block 510 and the center structure 515 (when used), and The first plate 505 and the second plate 520 can be made of an optically transparent material such as quartz or sapphire as described above in relation to the light pipe window structure 101. The loop block 510 and the center structure 515 (when used), and the first plate 505 and the second plate 520 may be joined by a bonding process (such as ceramic soldering technology, sealing glass bonding, diffusion soldering process, or the like). The appropriate bonding methods are coupled together. Although FIG. 5 does not show a housing (such as the housing 159 described in FIGS. 2B, 3 and 4), a housing can be coupled to the first and second plates 505 and 520 to provide sealing. Interior space. In an embodiment, when the first plate 505 and the second plate 520 are joined to the outermost loop block 510, the outermost loop block 510 can be used as a housing.

FIG. 6 is a perspective view of a portion of another embodiment of a light pipe window structure 600. The light pipe window structure 600 is shown with a first plate 505, which may be one of the first transparent plate 114 or the second transparent plate 115 as described above in relation to the light pipe window structure 101. The light pipe window structure 600 is similar to the light pipe window structure 500 described in FIG. 5, with the difference that it is disposed between the light pipe structures and/or is disposed to pass through (shown as a broken line on the figure) the light pipe structures. The spoke 612 includes a plurality of loop blocks 610. The opposing second panel 620 (where the second panel 620 of the portion of the display of FIG. 6) is joined to the surface 525 of the loop block 610 (and may include the topmost surface of the central structure 515 when including the central structure 515) To form a light pipe window structure 600. At least a portion of the loop blocks 610 can be a complete loop, or a plurality of arcuate segments forming a complete loop with a web 612 disposed therebetween. The second plate 620 can be one of the first transparent plate 114 or the second transparent plate 115 as described above in relation to the light pipe window structure 101. The light pipe window structure 600 can be combined with the first, third and fourth figures The process chamber 100 or process chamber 400 is used. When the light pipe window structure 600 is used with the process chamber 400, one or more of the center structure 515 and the innermost ring block 610 may not be needed in order to provide the center rod 415 and the lift pin 405 (eg, Pick up in Figure 4).

The spokes 612 can be used to reduce the tensile stress in the light pipe window structure 600. The spokes 612 can extend radially outward from the central structure 515 to the outermost loop block 610. The strips 612 can be symmetrically positioned between the loop blocks 610 or positioned to be worn in a geometrically symmetrical pattern (such as about 30 degree intervals, 45 degree intervals, 60 degree intervals, or 90 degree intervals). The loop blocks 610 are passed through. The loop blocks 610, the spokes 612, and the center structure 515 (when used), and the first plate 605 and the second plate 620 may be made of an optically transparent material (such as the light pipe window structure as described above) Made of quartz or sapphire 101. The loop blocks 610, the strips 612, the center structure 515 (when used), and the first plate 605 and the second plate 620 can be joined by a bonding process (such as ceramic soldering technology, sealing) Glass bonding, diffusion soldering processes, or other suitable bonding methods are coupled together. Although FIG. 6 does not show a housing (such as the housing 159 described in FIGS. 2B, 3 and 4), a housing can be coupled to the first plate 605 and the second plate 620 to provide sealing. Interior space. In an embodiment, when the first plate 605 and the second plate 620 are joined to the outermost loop block 610, the outermost loop block 610 can be used as a housing.

The use of the light pipe window structures 101, 500, and 600 described herein allows the lamp head assembly 105 (as shown in Figures 3 and 4) to be disposed outside of the interior of the chamber. In some embodiments, the first transparent plate 114 of the light pipe window structures 101, 500, and 600 described herein provides process chamber boundaries (eg, processing occurs) The boundary of the internal space). A seal, such as an O-ring and the like, can be used to seal the interior of the chamber space 120 and allow the base assembly 105 to be disposed outside of the interior space. The use of the light pipe window structures 101, 500, and 600 described herein provides for the cooling of the elevated lamp cap assembly 105 and the housing 123 (as in Figures 1, 3 and 4) while maintaining the energy source 162 (e.g., first and fourth) Figure) The intensity and / or radiation pattern. For example, if the base assembly 105 is disposed in the interior of the process chamber, the low pressure in the interior space 120 minimizes convective cooling of the energy source 162. Moreover, if the base assembly 105 is disposed in the interior space 120, a low pressure environment (and sometimes a combination with a readily ionized gas) can cause arcing of the electrical connections within the base assembly 105 that are coupled to the energy source 162.

Although the arc can be reduced by utilizing a lower voltage energy source 162, embodiments of the light pipe window structures 101, 500, and 600 described herein can achieve the use of a higher voltage energy source 162 without arcing. Thus, the use of the light pipe window structures 101, 500, and 600 described herein can achieve convective cooling of the lamp cap assembly 105 while maintaining the optical intensity and pattern provided by the energy source 162. In addition, a higher voltage energy source 162 (and lower current draw) can be utilized, which has many advantages. The low current/higher voltage energy source 162 that can be used in the base assembly 105 promotes faster and/or enhanced heating of the substrate 140. Moreover, the lower current draw in energy source 162 can achieve the use of smaller conductors and smaller, more robust lamp seals, both of which can save money and minimize the use of space in the lamp cap assembly 105.

While the above description is directed to a particular embodiment, other and further embodiments may be devised without departing from the basic scope of the invention, and the scope of the invention is determined by the scope of the appended claims.

101‧‧‧Light pipe window structure

105‧‧‧Light head assembly

106‧‧‧radiation heat source

108‧‧‧ side wall

123‧‧‧Shell

140‧‧‧Substrate

159‧‧‧Shell

160‧‧‧Light pipe structure

162‧‧‧Energy source

400‧‧‧Processing chamber

402‧‧‧ Back side

404‧‧‧Substrate support

405‧‧‧lifting pin

406‧‧‧Upper dome

408‧‧‧ base ring

410‧‧‧Flange

412‧‧‧Process area

414‧‧‧ flushing area

415‧‧‧ center pole

416‧‧‧ recess

418‧‧‧Seal

420‧‧‧ clamping ring

422‧‧‧ Round cover

424‧‧‧linear components

426‧‧‧Optical pyrometer

428‧‧‧ component side

430‧‧‧reflector

432‧‧‧埠

434‧‧‧ channel

436‧‧‧Process gas source

438‧‧‧Process gas inlet

440‧‧‧Flow path

442‧‧‧Flow path

444‧‧‧ gas export

446‧‧‧vacuum pump

448‧‧‧ flushing gas source

450‧‧‧ flushing gas inlet

452‧‧‧Flow path

454‧‧‧Flow path

460‧‧‧ Measure light pipe

462‧‧‧ sensor

464‧‧‧Fiber optic cable

Claims (23)

A light pipe window structure for use in a thermal processing chamber, the light pipe window structure comprising: a first transparent plate; a second transparent plate; a plurality of light pipe structures, wherein the plurality of light pipe structures are disposed in the first a transparent plate and a second transparent plate are bonded to the first transparent plate and the second transparent plate. The respective light pipe structures of the plurality of light pipe structures comprise a transparent material and have a longitudinal axis. The longitudinal axis is disposed in a substantially orthogonal relationship with a plane of the first or second transparent plate; and an outer casing that engages the first transparent plate and the second transparent plate and surrounds the plurality of light pipes structure. The light pipe window structure of claim 1, wherein the thickness of the first transparent plate is thicker than the thickness of the second transparent plate. The light pipe window structure of claim 1, wherein the first transparent plate comprises a recess. The light pipe window structure of claim 1, wherein each of the plurality of light pipe structures comprises a plurality of loop blocks. The light pipe window structure of claim 4, further comprising one or more strips disposed between the plurality of loop blocks. The light pipe window structure of claim 1, wherein each of the plurality of light pipe structures comprises a cylindrical structure. The light pipe window structure of claim 6, wherein each of the cylindrical structures comprises a solid structure having a circular cross section. The light pipe window structure of claim 6, wherein each of the cylindrical structures comprises a hollow structure having a circular cross section. The light pipe window structure of claim 1, wherein the outer casing comprises a sealing enclosure. A light pipe window structure for use in a thermal processing chamber, the light pipe window structure comprising: a first transparent plate; a second transparent plate, the second transparent plate being disposed to be substantially opposite to the first transparent plate An upper parallel relationship; and a plurality of light pipe structures disposed between the first transparent plate and the second transparent plate, wherein the thickness of the first transparent plate is greater than the thickness of the second transparent plate thick. The light pipe window structure of claim 10, wherein the first transparent plate comprises a recess. The light pipe window structure of claim 10, wherein each of the plurality of light pipe structures comprises one or more loop blocks. The light pipe window structure of claim 12, further comprising one or more webs disposed between the one or more loop blocks. The light pipe window structure of claim 10, wherein each of the plurality of light pipe structures comprises a cylindrical structure. The light pipe window structure of claim 14, wherein each of the cylindrical structures comprises a solid structure having a circular cross section. The light pipe window structure of claim 14, wherein each of the cylindrical structures comprises a hollow structure having a circular cross section. A process chamber includes: a chamber having an internal space; a light pipe window structure coupled to the chamber, the light pipe window structure having a first transparent plate, the light pipe window structure a first transparent plate in communication with the interior space of the chamber; and a radiant heat source coupled to a second transparent plate of the light pipe window structure at a location outside the interior space of the chamber, wherein The light pipe window structure includes a complex disposed between the first transparent plate and the second transparent plate Several light pipe structures. The process chamber of claim 17, wherein the first transparent plate comprises a recess. The process chamber of claim 17, wherein each of the plurality of light pipe structures comprises one or more loop blocks. The process chamber of claim 19, wherein the light pipe window structure further comprises one or more webs disposed between the one or more loop blocks. The process chamber of claim 17, wherein each of the plurality of light pipe structures comprises a cylindrical structure. The process chamber of claim 21, wherein each of the cylindrical structures comprises a solid structure having a circular cross section. The process chamber of claim 21, wherein each of the cylindrical structures comprises a hollow structure having a circular cross section.