Carrier plate for local heating in thermal processing systems

Abstract

Thermal processing device (100, 400), comprising: a plurality of heat sources (130, 140) configured to heat a workpiece (110), a rotatable support plate (120, 410, 700) operable to support the workpiece (110) during thermal processing, the rotatable support plate (120, 410, 700) comprising: a light-transmissive support structure (115) configured to come into contact with the workpiece (110), the light-transmissive support structure (115) having a first end (212) and a second end (214), the first end (212) of the support structure being configured to support the workpiece (110); and a light source (430) operable to emit coherent light through the light-transmissive support structure (115) such that the coherent light (435) heats a portion of the workpiece (110) in contact with the light-transmissive support structure (115); wherein the light-transmissive support structure (115) has a plurality of support pins (210, 415); and the light-transmissive support structure (115) has a base (135, 230, 420), wherein the base (135, 230, 420) has a semi-annular opaque portion (520) arranged between at least two of the plurality of support pins (210, 415), wherein the semi-annular opaque portion (520) is configured to prevent the coherent light (435) of the light source (430) from heating the workpiece (110).

Description

[0001] The present invention relates generally to thermal processing systems.

[0002] A thermal processing chamber, as used herein, refers to a device that heats workpieces, such as semiconductor wafers. Such devices may include a support plate for supporting one or more semiconductor wafers and an energy source for heating the semiconductor wafers, such as heating lamps, lasers, or other heat sources. During heat treatment, the semiconductor wafers may be heated under controlled conditions according to a preset temperature regime.

[0003] Many semiconductor heating processes require heating a wafer to high temperatures so that various chemical and physical transformations can occur as the wafer is fabricated into a device(s). During rapid thermal processing, for example, semiconductor wafers can be heated by an array of lamps through the support plate to temperatures of approximately 300°C to approximately 1200°C for times typically less than a few minutes. During these processes, a primary goal may be to heat the wafers as uniformly as possible.

[0004] US 2016 / 0 351 424 A1 describes a plurality of support pins that support a semiconductor wafer and are arranged upright on the top surface of a susceptor. A condenser lens is located on the underside of the susceptor, opposite the support pins with respect to the susceptor. The condenser lens is arranged such that its optical axis coincides with the central axis of the corresponding support pin.

[0005] US 2014 / 0 105 582 A1 describes edge rings for substrate carriers of semiconductor substrate process chambers. An edge ring for a semiconductor process chamber comprises an annular body having a central opening, an inner edge, an outer edge, a top surface, and a bottom surface, an inner lip disposed near the inner edge and extending downwardly from the top surface, and a plurality of projections extending upwardly from the inner lip and disposed along the inner edge of the annular body.

[0006] US 2017 / 0 076 965 A1 discloses a transparent plate and a substrate processing system containing this plate. The substrate processing system may include a chamber, a lamp provided below the chamber, and a plate provided in the chamber for loading a substrate.

[0007] US 2017 / 0 243 771 A1 describes a semiconductor wafer held by a holder in a chamber, which is irradiated and heated with halogen light emitted by several halogen lamps.

[0008] US 2018 / 0 002 830 A1 describes susceptor assemblies comprising a susceptor having a top surface with a plurality of recesses and a bottom surface.

[0009] The invention is defined by the features of the independent claims. Preferred embodiments are defined by the features of the dependent claims.

[0010] Aspects and advantages of embodiments of the present invention will be set forth in part in the description which follows, or may be learned from the description, or may be learned by practice of the embodiments.

[0011] An exemplary aspect of the present invention relates to a thermal processing apparatus. The apparatus includes a plurality of heat sources configured to heat a workpiece. The apparatus includes a rotatable support plate operable to support the workpiece during thermal processing. The rotatable support plate includes a transparent support structure configured to contact the workpiece. The transparent support structure has a first end and a second end. The first end of the support structure is configured to support the workpiece. The apparatus includes a light source operable to emit coherent light through the transparent support structure such that the coherent light heats a portion of the workpiece in contact with the transparent support structure.

[0012] Other exemplary aspects of the present invention relate to systems, methods, apparatus, and processes for thermally treating a semiconductor substrate.

[0013] These and other features, aspects, and advantages of various embodiments will become more apparent with reference to the following description and the appended claims. The accompanying drawings, which are incorporated herein by reference, illustrate embodiments of the present invention and, together with the description, serve to explain the related principles.

[0014] The description, in which reference is made to the accompanying figures, includes a detailed discussion of embodiments directed to a person of ordinary skill in the art; they show: Fig. 1 illustrates an exemplary RTP (Rapid Thermal Processing) system including a carrier plate with spatially arranged low transmission regions in accordance with exemplary embodiments of the present invention; Fig. 2A and Fig. 2B shows an exemplary carrier plate with spatially arranged low transmission regions according to exemplary embodiments of the present invention; Fig. 3 is a flowchart of a process for heating a workpiece through a support plate having spatially arranged low transmission regions according to exemplary embodiments of the present invention; Fig. 4 illustrates an exemplary RTP system with a rotatable support plate and a coherent light source according to exemplary embodiments of the present invention; Fig. 5 shows an exemplary base with spatially arranged low transmission regions according to exemplary embodiments of the present invention; Fig. 6 illustrates an example of coherent light heating a workpiece through a rotatable support plate having spatially arranged low transmission regions, according to exemplary embodiments of the present invention; Fig. 7 shows an exemplary rotatable support plate with an annular support according to exemplary embodiments of the present invention; and Fig. 8 is a flow diagram of a process for heating a workpiece based on a rotatable support plate and a coherent light source according to exemplary embodiments of the present invention.

[0015] Reference will now be made in detail to embodiments, one or more examples of which are illustrated in the drawings. Each example is provided to illustrate the embodiments and is not intended to limit the present invention. Indeed, those skilled in the art will appreciate that various modifications and variations may be made to the embodiments within the scope of the present invention. For example, features shown or described as part of one embodiment may be used with another embodiment to yield a still further embodiment. Therefore, aspects of the present invention are intended to cover such modifications and variations.

[0016] Exemplary aspects of the present invention relate to support plates for local heating in thermal processing systems to uniformly heat workpieces such as semiconductor workpieces, optoelectronic workpieces, flat panel displays, or other suitable workpieces. The workpiece materials may include, for example, silicon, silicon-germanium, glass, plastic, or another suitable material. In some embodiments, the workpieces may be semiconductor wafers. The support plates may be used to support workpieces in various thermal processing systems that implement various workpiece manufacturing processes, such as, but not limited to, vacuum annealing processes, rapid thermal processing, etc. The support plates may be applied to the above thermal processing systems, wherein one side (e.g.a back) or both sides of the workpiece are exposed to one or more heat sources.

[0017] A thermal processing chamber may include a heat source for emitting light ranging in the electromagnetic spectrum from ultraviolet to near-infrared. To expose one or both sides of a workpiece to the heat source, the workpiece is supported by one or more support pins mounted on a support structure, typically on a base beneath the workpiece. The support pins and base form a support plate. In some configurations, the base is made of a highly transparent, uniform material (e.g., fused silica) to prevent light from obstructing heat sources. However, light obstruction by the support pins cannot be avoided. Therefore, a pin spot effect can occur, reducing the workpiece temperature at areas of the workpiece that contact the support pins.

[0018] During workpiece heating, the workpiece is not in thermal equilibrium with the walls and support plate in the thermal processing chamber. Although thermal conduction from a holding pin material (e.g., quartz material) is low and the contact area of the workpiece in contact with the holding pin is small, a cooling effect still occurs through thermal conduction into the cooler contact area associated with the holding pin. In addition, during rapid thermal transients (e.g., rapid thermal processing applications), the added thermal mass of a holding pin can cause a reduced heating rate of the workpiece in the contact area.

[0019] As a result, the workpiece temperature in the contact area decreases, forming a cold spot. Typically, one or more cold spots may remain at one or more contact areas of the workpiece that are in contact with the support plate. The cold spots can be caused by three main effects, such as shadowing, thermal conduction, and higher thermal mass. According to exemplary aspects of the present invention, local heating of the contact areas can be used to compensate for the cold spots remaining on the workpiece.

[0020] An exemplary aspect of the present invention relates to a support plate for localized heating in a thermal processing system to compensate for cold spots on a workpiece. Localized heating is achieved by modifying the heat transfer of a support plate such that one or more portions of the support plate near the areas causing cold spots transfer more heat than the rest of the support plate.

[0021] For example, the carrier plate may have a base and one or more retaining pins that are in contact with a workpiece during processing. One or more heat sources (e.g., lamp, laser, or other heat sources) are used to heat the workpiece. Localized heating is achieved by modifying an optical transmission of the carrier plate such that the areas of the carrier plate near the retaining pins (e.g., under and / or around the retaining pins, above and / or around the retaining pins, etc.) transmit more light from the heat sources than the rest of the carrier plate. For example, the optical transmission of the carrier plate is modified such that only sections of the base where the retaining pins are connected to the base remain unchanged with respect to untreated material (e.g., fused silica) of the base.In sections of the base away from the support pins, the optical transmission is reduced by treating the fused silica of the base. The treatment to reduce optical transmission can include grinding, coating, engraving, or doping. Sections of the base with untreated fused silica transfer a higher heat flux compared to sections of the base with treated fused silica. Therefore, the workpiece is exposed to a higher heat flux from the sections of the base near the support pins, resulting in compensation for cold spots caused by the support pins.

[0022] Another exemplary aspect of the present invention relates to a thermal processing apparatus for local heating in thermal processing systems to compensate for cold spots on the workpiece. The thermal processing apparatus comprises one or more heat sources (e.g., lamps or any other heat sources), a coherent light source (e.g., a laser or other suitable source), and a rotatable support platen with a support structure (e.g., one or more retaining pins or an annular support, etc.). Cold spots caused by contact of the workpiece with the support structure can be compensated for by heating the workpiece by the coherent light source through the support structure in addition to global heating of the workpiece by light from the heat sources. Therefore, the cold spots are heated locally by light from the coherent light source.

[0023] For example, in some embodiments, a cold spot is compensated by directing a beam of coherent light (e.g., a laser beam) from the coherent light source onto a locating pin. The locating pin is made of a translucent material such as quartz. The coherent light passes through the translucent locating pin to heat the portion of the workpiece in contact with the locating pin.

[0024] In some embodiments, the coherent light source is mounted on a stationary part of the thermal processing apparatus so that the support pin rotates during the rotational movement of the support platen due to the coherent light. In some embodiments, the coherent light source can be controlled to turn on and off synchronously with the workpiece rotation to heat only a contact area of the workpiece that is in contact with the support pin. For example, the coherent light source can be controlled to emit coherent light only when the support pin passes in front of the coherent light source during the rotational movement of the support platen.

[0025] In some embodiments, synchronization can be achieved by shaping the power of the coherent light emitted by the light source. For example, the power of the coherent light can be controlled to have a first value when the tether pin does not pass in front of the coherent light source. As the tether pin approaches the coherent light source, the power of the coherent light can be increased. As the tether pin passes through the coherent light source, the power of the coherent light can be controlled to have a second value that is greater than the first value. As the tether pin rotates away from the coherent light source, the power of the coherent light can be decreased, for example, back to the first value or to a third value that is smaller than the second value.

[0026] In some embodiments, this synchronization can be achieved by an electrical control circuit in which a trigger signal is generated from a sensor signal indicative of a rotational orientation and a rotational speed. For example, based on known information of the rotational orientation and rotational speed of the rotatable support plate or the workpiece, emission of the coherent light source can be synchronized with movement of the rotatable support plate. The coherent light source emits coherent light into the support pin and onto the workpiece when the support pin passes in front of the coherent light source during rotation of the support plate, and the coherent light source stops emitting the coherent light when the support pin is not in front of the coherent light source.

[0027] In some embodiments, local heating can be achieved by modifying an optical transmission of the base such that one or more portions of the base located near the support pins transmit the coherent light, and the rest of the base is opaque to the coherent light from the coherent light source. The opaque portions of the base can be created by grinding, coating, engraving, or doping. The opaque portions of the base can be small so as not to obstruct the light from the heat sources. In some embodiments, an opaque portion is a wavelength-selective coating on one side (e.g., on a back side) or on both sides of the base in the form of a semi-annular opaque portion (e.g., a segmented ring).The semi-annular opaque sections may extend between support pins along a path of coherent light along the base during rotational movement of the support plate relative to the coherent light source.

[0028] In some embodiments, a width of the semi-annular opaque portion may be less than or equal to a diameter of a contact area of the coherent light in contact with the base. Examples of the contact area include a focal spot of the coherent light on the base or a cross-section of the coherent light in contact with the base. The wavelength-selective coating is selected such that only a narrow band of the coherent light radiation is blocked, while a broad band of light from the heat sources is almost completely transmitted, thereby reducing an impact on global temperature uniformity. Therefore, the synchronization of the coherent light source with the rotational movement of the rotatable support plate is inherently achieved by the rotatable support plate itself.In this exemplary embodiment, the coherent light source may remain switched on and emit coherent light throughout an entire thermal cycle or relevant portions of the thermal cycle.

[0029] In some embodiments, the support plate may comprise an annular support. The annular support may be made of a light-transmissive material (e.g., quartz) that allows the passage of coherent light from the coherent light source to heat the workpiece. In this exemplary embodiment, the coherent light source may remain switched on and emit coherent light throughout an entire heat cycle or relevant portions of the heat cycle. The annular support may be mounted to the base centrally with respect to a center of the workpiece. A height of the annular support may approximately correspond to the height of a support pin. Without additional heating, the annular support may cause a rotationally symmetric cold pattern on the workpiece. By arranging the coherent light source nearby (e.g.,below) the annular support and by rotating the workpiece and the annular support about their common center, the cold pattern is compensated by continuously emitting coherent light from the coherent light source through the annular support onto the workpiece.

[0030] Aspects of the present invention can achieve a number of technical effects and advantages. For example, aspects of the present invention can reduce the occurrence of cold spots associated with retaining pins in thermal processing tools.

[0031] Variations and modifications may be made to these exemplary embodiments of the present invention. Throughout the description, singular forms such as "a," "an," "and," and "the" include the corresponding plural forms unless the context clearly indicates otherwise. Terms such as "first," "second," "third," and "fourth" are used as identifiers and refer to a processing order. Example aspects may be discussed with reference to a "substrate," a "wafer," or a "workpiece" for purposes of illustration and discussion. It will be apparent to one of ordinary skill in the art from the description provided herein that example aspects of the present invention may be used with any suitable workpiece. The use of the term "approximately" or "about" in connection with a numerical value refers to a value within 20% of the stated numerical value.

[0032] Hereinafter, exemplary embodiments of the present invention will be discussed in detail with reference to the figures. Fig. Figure 1 illustrates an exemplary RTP (Rapid Thermal Processing) system 100 including a support plate 120 with spatially arranged low-transmission regions according to exemplary embodiments of the present invention. As illustrated, the RTP system 100 includes an RTP chamber 105, a workpiece 110, a support plate 120, heat sources 130 and 140, air bearings 145, a pyrometer 165, a control unit 175, a door 180, and a gas flow controller 185.

[0033] The workpiece 110 to be processed is supported in the RTP chamber 105 (e.g., a quartz RTP chamber) by the support plate 120. The support plate 120 supports the workpiece 110 during thermal processing. The support plate 120 has a rotatable base 135 and at least one support structure 115 extending from the rotatable base 135. A support structure describes a structure that is in contact with a workpiece and supports the workpiece during thermal processing. Examples of the support structure are one or more retaining pins, an annular support, or another suitable support that is in contact with a workpiece and supports the workpiece. As shown in Fig. 1, the support structure 115 includes one or more support pins (only one of which is shown). The support structure 115 and the rotatable base 135 can transfer heat from the heat sources 140 and absorb heat from the workpiece 110. In some embodiments, the support structure 115 and the rotatable base 135 can be made of quartz. The rotatable base 135 rotates the workpiece 110 at a defined rotational orientation and at a defined speed, as described in more detail below.

[0034] A guard ring (not shown) may be used to reduce edge effects of radiation from one or more edges of the workpiece 110. An end plate 190 is sealed to the chamber 105, and a door 180 allows the workpiece 110 to be introduced and, when closed, allows the chamber 105 to be sealed and a process gas 125 to be introduced into the chamber 105. Two banks of heat sources (e.g., lamps or other suitable heat sources) 130 and 140 are shown on either side of the workpiece 110. The control unit 175 (e.g., a computer, one or more microcontrollers, other control device(s), etc.) is used to control the heat sources 130 and 140. The control unit 175 can be used to control the gas flow regulator 185, the door 180 and / or the temperature measurement system, referred to herein as pyrometer 165.

[0035] A gas stream 150 may be an inert gas that does not react with the workpiece 110, or the gas stream 150 may be a reactive gas such as oxygen or nitrogen that reacts with the material of the workpiece 110 (e.g., a semiconductor wafer, etc.) to form a layer on the workpiece 110. The gas stream 150 may be a gas that may contain a silicon compound that reacts at a heated surface of the workpiece 110 being processed to form a layer on the heated surface without consuming any material from the surface of the workpiece 110. When the gas stream 150 reacts to form a layer on the surface, the process is referred to as rapid thermal chemical vapor deposition (RT-CVD).In some embodiments, an electric current may be passed through the atmosphere in the RTP system 100 to generate ions reactive with or at the surface and to supply additional energy to the surface by bombarding the surface with energetic ions.

[0036] The control unit 175 controls the rotatable base 135 to rotate the workpiece 110. For example, the control unit 175 generates an instruction that defines the rotational orientation and speed of the rotatable base 135 and controls the rotatable base 135 to rotate the workpiece 110 at the defined rotational orientation and speed. The rotatable base 135 is supported by the air bearings 145. The gas flow 150 impinging on the rotatable base 135 causes the rotatable base 135 to rotate about an axis 155.

[0037] In some embodiments, the rotatable base 135 may include a first portion associated with a first heat transfer and a second portion associated with a second heat transfer. The second heat transfer is different from the first heat transfer. The second portion is disposed proximate the support pins 115. Examples of the rotatable base 135 are described below in connection with the Fig. 2A and Fig. 2B is described in more detail.

[0038] The Fig. 2A and Fig. 2B show an exemplary carrier plate 200 with spatially arranged low transmission regions according to exemplary embodiments of the present invention. In the embodiments of Fig. 2A and Fig. 2B, the support plate 200 has three retaining pins 210 and a rotatable base 230. More or fewer retaining pins may be used within the scope of the present invention.

[0039] In some embodiments, the carrier plate 200 is an exemplary embodiment of the carrier plate 120 ( Fig. 1) and a retaining pin 210 is an embodiment of the exemplary retaining pin 115 ( Fig. 1). Each support pin 210 has a first end 212 and a second end 214. The first end 212 of the support pin 210 contacts and supports a workpiece (not shown). The second end 214 of the support pin 210 contacts (e.g., is connected) the rotatable base 230. In some embodiments, the support pin(s) 210 may be integral with the rotatable base 230.

[0040] As illustrated, the rotatable base 230 includes three circular regions 220. Each circular region 220 is disposed near the second end 214 of a support pin 210. A diameter of a circular region 220 is larger than a diameter of a contact region of a corresponding support pin 210 that is in contact with the rotatable base 230. A center of a circular region 220 coincides with a center of a corresponding support pin 210. The remaining regions 240 of the rotatable base 230 define regions, except for the three circular regions 220, within the rotatable base 230. The remaining regions 240 are associated with a first heat transfer, and the three circular regions 220 are associated with a second heat transfer. The second heat transfer may be different from the first heat transfer. For example, the second heat transfer may be higher than the first heat transfer.The regions 240 are referred to as low-transmission regions, which have lower heat transfer than the circular regions 220. Therefore, the circular regions 220 transfer more heat than the remaining regions 240 to compensate for cold spots that may remain on the workpiece supported by the support pins 210. As a result, more even heat is distributed across the support plate 200 to the workpiece.

[0041] For purposes of illustration and discussion, the present invention will be discussed in connection with regions 220 having a circular shape. Those of ordinary skill in the art will understand from the description presented herein that regions 220 may have other shapes within the scope of the present invention.

[0042] In some embodiments, an optical transmission of the carrier plate 200 is modified such that the circular regions 220 remain unchanged with respect to untreated material (e.g., untreated quartz) of the rotatable base 230. The remaining regions may be treated material (e.g., treated quartz) with a reduced optical transmission relative to the circular regions 220. The treated quartz may be treated by one or more processes including grinding, coating, engraving, or doping. The circular regions 220 with untreated quartz transfer a higher heat flux compared to the remaining regions 240 with treated quartz. Therefore, the workpiece is exposed to a higher heat flux from the circular regions 220, resulting in compensation for cold spots caused by the support pins 210.

[0043] For the purposes of illustration and discussion, aspects of the present invention will be discussed with reference to a support plate having one or more support pins as a support structure and having a rotatable base. Those of ordinary skill in the art will understand from the description presented herein that non-rotatable bases may be used within the scope of the present invention. For example, a non-rotatable base may have a first portion associated with a first heat transfer and a second portion associated with a second heat transfer. The second heat transfer is different from the first heat transfer, and the second portion is disposed proximate a support structure (e.g., a support pin, an annular support, etc.).One of ordinary skill in the art will understand from the description presented herein that any support structure (e.g., a retaining pin, an annular support, a support structure of any shape, etc.) may be used within the scope of the present invention.

[0044] Fig. 3 shows a flow diagram of a process (300) for heating a workpiece through a support plate with spatially arranged low transmission regions according to exemplary embodiments of the present invention. The process (300) can be performed using the RTP system 100 of Fig. 1. As discussed in detail below, the process (300) according to exemplary aspects of the present invention may be implemented using other thermal processing systems within the scope of the present invention. Fig. Figure 3 shows steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art will understand from the description presented herein that various steps of any of the methods described herein may be omitted, expanded, performed concurrently, rearranged, and / or modified in various ways within the scope of the present invention. Furthermore, various additional steps (not shown) may be performed within the scope of the present invention.

[0045] At (310), the process may include placing a workpiece on a support plate in a processing chamber. For example, in the embodiment of Fig. 1, the support plate 120 includes the support pins 115, and the rotatable base 135. The workpiece 110 is placed on the support pins 115 in the RTP chamber 120 via the door 180. In some embodiments, the support plate 120 may be used in an annealing chamber. For example, a workpiece may be placed on the support plate 120 in the annealing chamber for annealing. In some embodiments, the support plate 120 may include other support structures (e.g., an annular support, a support structure of any shape, etc.). In some embodiments, the support plate 120 may include a non-rotatable base with spatially arranged low-transmission regions.

[0046] At (320), the process may include rotating the workpiece by the support plate in the processing chamber. For example, in the embodiment of Fig. 1, the control unit 175 causes the rotatable base 135 to rotate the workpiece 110 in the RTP chamber 105.

[0047] At (330), the process may include heating the workpiece by multiple heat sources through the support plate. For example, in the embodiment of Fig. 1 the control unit 175 the heat sources 140 to heat the workpiece 110 through the rotatable base 135 and the holding pins 115 to a preset temperature.

[0048] At (340), the process may include removing the workpiece from the support plate. For example, in the embodiment of Fig. 1 the workpiece 110 is removed from the holding pins 115 and removed from the RTP chamber 105 via the door 180.

[0049] Fig. Figure 4 shows an exemplary RTP system 400 with a rotatable support plate 410 and a coherent light source 430 according to exemplary embodiments of the present invention. As illustrated, the RTP system 400 includes the RTP chamber 105, the workpiece 110, the rotatable support plate 410 with support pins 415 and a base 420, a coherent light source 430, a control unit 440, heat sources 130 and 140, air bearings 145, the pyrometer 165, the door 180, and the gas flow controller 185.

[0050] The coherent light source 430 (e.g., a laser) can supply coherent light 435 to the chamber 105. In some embodiments, the coherent light source 430 is located outside the chamber 105 and transmits light 435 to the chamber 105 via an optical conduit or light guide 435 (e.g., fiber optic).

[0051] The rotatable support plate 410 supports the workpiece 110 during thermal processing. The rotatable support plate 410 includes a light-transmissive support structure and a rotatable base 415. The light-transmissive support structure describes a structure that is in contact with the workpiece 110 and supports the workpiece and transmits light 435 from the coherent light source 430 (e.g., from a laser) to the workpiece 110 during thermal processing. Examples of the light-transmissive support structure include one or more retaining pins, an annular support, or any other suitable support that is in contact with the workpiece 110 and supports the workpiece and transmits light to the workpiece 110.

[0052] The translucent support structure has a first end and a second end. The first end of the translucent support plate is arranged to support the workpiece 110. The second end of the translucent support plate is in contact with (e.g., connected to) a first surface of the rotatable base 420. In the exemplary embodiment of Fig. 1, the translucent support structure includes one or more support pins 415 (only one of which is shown). One end of a support pin 415 contacts a backside of the workpiece 110, and the other end of the support pin 415 contacts a surface of the base 420. The base 420 rotates the workpiece 110 in a defined rotational orientation and at a defined speed based on an instruction received from the control unit 440, as described in more detail below.

[0053] In some embodiments, the translucent support structure and base 420 may transfer heat from the heat sources 140 and absorb heat from the workpiece 110. For example, the translucent support structure and base 420 may be made of quartz.

[0054] In some embodiments, the rotatable support plate 410 includes one or more retaining pins 415 and the base 420 with a semi-annular opaque portion (in the Fig. 5 and Fig. 6) disposed between at least two of the support pins 415. The semi-annular opaque portion can prevent the coherent light of the coherent light source 430 from heating the workpiece 110, so that the coherent light source 430 can continuously emit the coherent light onto the base 420 during the rotational movement of the workpiece 110.

[0055] In some embodiments, the rotatable support plate 410 comprises an annular support (in Fig. 7) and the base 420. For example, both the annular support and the base 420 may be made of a light-transmitting material (e.g., quartz) that allows the passage of coherent light continuously emitted by the coherent light source 430 to heat the workpiece 110.

[0056] Coherent light source 430 emits coherent light 435 through rotatable base 420 and the translucent support structure, such that the coherent light heats a portion of workpiece 110 in contact with the translucent support structure. Examples of coherent light source 430 include a continuous wave laser, a pulsed laser, or other suitable light source that emits coherent light.

[0057] In the exemplary embodiment of Fig. 4, the coherent light source 430 is mounted on a stationary part of the RTP chamber 105, so that the support pin 415 rotates during the rotational movement of the rotatable support plate 410 due to the coherent light 435. The coherent light source 430 emits coherent light 435 onto a backside of the base 420, and the emitted coherent light can pass through the support pin 415 to heat a contact area of the workpiece 110 that is in contact with the support pin 415. Thus, a cold spot caused by the contact of the workpiece 110 with the support pin 415 can be compensated for by heating the workpiece 110 via the coherent light source 430 through the support pin 415, in addition to the global heating of the workpiece 110 by light from the heat sources 140.In some embodiments, the coherent light source 430 is controlled by the control unit 440 to turn on and off synchronously with the rotational movement of the workpiece 110 to heat a contact area of the workpiece that is in contact with the support pin 415. The control unit 440 controls one or more components among the rotatable base 415, the coherent light source 430, the heat sources 130 and 140, the gas flow regulator 185, the door 180, and the pyrometer 165. The control unit 440 controls the base 420 to rotate the workpiece 110 at a defined rotational orientation and a defined speed. For example, the control unit 440 generates an instruction defining a rotational orientation and a rotational speed of the base 420 and controls the base 420 to rotate the workpiece 110 at the defined rotational orientation and the defined rotational speed.In some embodiments, the control unit 440 controls the coherent light source 430 to emit coherent light 435 based on the rotational orientation and rotational speed of the base 420. For example, the control unit 440 may include an electrical control circuit that generates a trigger signal for triggering the coherent light source 430 to emit coherent light 435 based on a sensor signal indicative of a rotational orientation and rotational speed of the base 420.

[0058] In some embodiments, the control unit 440 synchronizes emission of the coherent light from the coherent light source 430 with movement of the base 420 such that the coherent light source 430 emits the coherent light into one of the support pins 415 and onto the workpiece 110 when that support pin 415 passes the coherent light source 430 during rotational movement of the base 420, and such that the coherent light source 430 stops emitting the coherent light when that support pin 415 is not in front of the coherent light source. For example, the control unit 440 generates an instruction that instructs the coherent light source 430 to emit coherent light based on a rotational orientation and rotational speed of the base 420.The instruction may include a command that instructs the coherent light source 430 to emit coherent light, a command that instructs the coherent light source 430 to stop emitting the coherent light, a command that calculates a time interval between one emission and a subsequent emission of the coherent light source 430 based on the rotational orientation and rotational speed of the workpiece 110, etc.

[0059] In some embodiments, the control unit 440 controls the coherent light source 430 to continuously emit the coherent light into the light-transmissive support structure. For example, the control unit 440 generates an instruction instructing the coherent light source 430 to remain on and continuously emit the coherent light onto the base 420. The base 420 may include a semi-annular opaque portion that shields coherent light from the coherent light source 430 from heating portions of the workpiece 110 that are not in contact with the support structure. When the retaining pin 415 is not disposed in front of the coherent light source 430, the control unit 440 instructs the coherent light source 430 to remain on and continuously emit coherent light onto the semi-annular opaque portion, such that the emitted coherent light is blocked by the semi-annular opaque portion.When the holding pin 415 passes in front of the continuously emitted coherent light, the coherent light passes through the holding pin 415 to heat the workpiece 110.

[0060] In another example, the control unit 440 generates an instruction that instructs the coherent light source 430 to remain on and continuously emit the coherent light onto the rotatable support plate 410 having an annular support. During the rotational movement of the workpiece 110, the annular support always passes by the coherent light source 430 and transmits the coherent light to heat the workpiece 110. The control unit 440 instructs the coherent light source 430 to continuously emit the coherent light into the annular support. Therefore, a cold pattern caused by the annular support is compensated by continuously radiating the coherent light from the coherent light source 430 through the annular support onto the workpiece 110.

[0061] Fig. 5 shows an exemplary base 500 with spatially arranged low transmission regions according to exemplary embodiments of the present invention. In the embodiment of Fig. 5, the base 500 may be an embodiment of the base 420. The base 500 includes three circular sections 510, a plurality of semi-annular opaque sections 520, and remaining sections 530. A circular section 510 is a contact area of a workpiece that contacts a retaining pin (not shown). Each semi-annular opaque section is disposed between any two of the three circular sections 510. The remaining sections 530 of the base 500 describe sections other than the three circular sections 510 and the plurality of semi-annular opaque sections 520 within the base 500.

[0062] Fig. 6 shows an example of coherent light 610 heating the workpiece 110 through the base 500 and the support pin 415, according to exemplary embodiments of the present invention. The coherent light 610 is emitted from a coherent light source (not shown). The coherent light 610 passes through the support pin 415 to heat the workpiece 110. As the base 500 rotates, the support pin 415 is not positioned in front of the coherent light 610; rather, a semi-annular opaque portion 520 bypasses the coherent light 610 and prevents the coherent light 610 from heating the workpiece 110. Therefore, cold spots are compensated for by continuously emitting coherent light onto each support pin during the rotational movement of the base 500.

[0063] In the embodiment of the Fig. 5 and Fig. 6, a width of the semi-annular opaque portion 520 is not smaller than a diameter of a contact area of the coherent light 610 in contact with the base 500. Examples of the contact area of the coherent light 610 are a focal spot of the coherent light 610 on the base 500 or a cross-section of the coherent light 610 in contact with the base 500. The round portions 510 and the remaining portions 530 may remain unchanged with respect to untreated material (e.g., untreated quartz) of the base 500. The semi-annular opaque portions 520 may be treated material (e.g., treated quartz) that prevents coherent light from a coherent light source (not shown) from heating the workpiece 110. The treated material may be treated by one or more processes including grinding, coating, engraving, and doping.In some embodiments, the semi-annular opaque sections 520 include a wavelength-selective coating on one side (e.g., on a back side) or on both sides of the base 500. The wavelength-selective coating is selected such that only a narrow band of coherent light radiation is blocked, while a broad band of light from the heat sources is almost completely transmitted, thereby reducing an impact on global temperature uniformity.

[0064] In some embodiments, the semi-annular opaque sections 520 may extend between support pins 415 along a path of coherent light 610 along the base 500 during rotational movement of the base 500 relative to a coherent light source (not shown). The semi-annular opaque sections 520 may be small so that they do not obstruct light from heat sources (not shown). The semi-annular opaque sections 520 are also referred to as low-transmission regions, which prevent coherent light from heating a workpiece.

[0065] For the purposes of illustration and discussion, aspects of the present invention will be discussed with reference to a rotatable support plate having three support pins as translucent support structures. Those of ordinary skill in the art will understand from the present description that, within the scope of the present invention, multiple separate supports having a rotatable, symmetrical arrangement may be used. For example, multiple supports are not connected to one another, but these multiple supports are arranged in a rotationally symmetrical pattern on the base. A support may have any shape.

[0066] Fig. 7 shows an exemplary rotatable support plate 700 with an annular support 720 according to exemplary embodiments of the present invention. In the embodiment of Fig. 7, the rotatable support plate 700 may be an embodiment of the rotatable support plate 410. The rotatable support plate 700 includes a rotatable base 710 and the annular support 720. The annular support 720 is centered with respect to a center of the rotatable base 710. In some embodiments, the annular support 720 is centered with respect to a center of a workpiece (not shown) in contact with the annular support 720. A width of the annular support 720 is not less than a diameter of a contact area of the coherent light (not shown) in contact with the annular support 720. Examples of the contact area of the coherent light include a focal spot of the coherent light on the annular support 720 or a cross-section of the coherent light in contact with the annular support 720.In some embodiments, a height of the annular support 710 may be approximately equal to a height of the support pin 415. In some embodiments, both the rotatable base 710 and the annular support 720 may be made of a light-transmitting material (e.g., untreated quartz) that allows the passage of coherent light from a coherent light source to heat a workpiece. Therefore, a coherent light source may continuously emit coherent light that passes through the rotatable base 710 and the annular support 720 to heat a workpiece in contact with the annular support 720. Furthermore, a cold pattern caused by the annular support 720 may be compensated by continuous emission from the coherent light source to heat the workpiece.

[0067] For the purposes of illustration and discussion, aspects of the present invention will be discussed with reference to a rotatable support plate having an annular support as a translucent support structure. Those of ordinary skill in the art will understand from the present description that any translucent support structure having a rotatable, symmetrical shape may be used within the scope of the present invention.

[0068] Fig. Figure 8 shows a flow diagram of a process (800) for heating a workpiece based on a rotatable support plate and a coherent light source according to exemplary embodiments of the present invention. The process (800) can be implemented using the RTP system 400. However, as discussed in detail below, the process (800) according to exemplary aspects of the present invention can be implemented using other thermal processing systems within the scope of the present invention. Fig. 8 shows steps performed in a particular order for purposes of illustration and discussion. Those of ordinary skill in the art will understand from this description that various steps of any method described herein may be omitted, expanded, performed concurrently, rearranged, and / or modified in various ways within the scope of the present invention. Furthermore, various additional steps (not shown) may be performed within the scope of the present invention.

[0069] At (810), the process may include placing a workpiece on a rotatable support plate in a processing chamber. The rotatable support plate includes a translucent support structure and a base. For example, in the embodiment of Fig. 4, the rotatable support plate 410 includes support pins 415 and a base 420. The workpiece 110 is placed through the door 180 onto the support pins 415 in the RTP chamber 105. In some embodiments, the rotatable support plate 410 can be used in an annealing chamber. For example, a workpiece for annealing can be placed on the rotatable support plate 410 in the annealing chamber.

[0070] At (820), the process may include heating the workpiece using one or more heat sources. For example, in the embodiment of Fig. 4 the control unit 440 the heat sources 140 to heat the workpiece 110 through the base 420 and the holding pins 415 to a preset temperature.

[0071] At (830), the process may include rotating the workpiece with the rotatable support plate relative to the one or more heat sources while heating the workpiece. For example, in the embodiment of Fig. 4 the control unit 440 instructs the base 420 to rotate the workpiece 110 in the RTP chamber 105 with a defined rotational orientation and a defined speed.

[0072] At (840), the process may include emitting coherent light from a coherent light source through the base and the translucent support structure such that the coherent light heats a portion of the workpiece that is in contact with the translucent support structure. For example, in the embodiment of Fig. 4, the control unit 440 controls the emission of coherent light from the coherent light source 430 with a movement of the base 420 such that the coherent light source 430 emits the coherent light into one of the holding pins 415 and onto the workpiece 110 when the holding pin 415 passes the coherent light source 430 during the rotation of the base 420, and such that the coherent light source 430 interrupts the emission of the coherent light when this holding pin 415 is not arranged in front of the coherent light source 430. In another example, the control unit 440 controls the coherent light source 430 to continuously emit the coherent light in order to move the workpiece 110 through the rotatable support plate 410 (e.g., a rotatable support plate with holding pins 415 and with the base 500 in the Fig. 5 and Fig. 6 or the rotating support plate 700 in Fig. 7) to heat.

[0073] At (850), the process may include removing the workpiece from the rotatable support plate. For example, in the embodiment of Fig. 4 the workpiece 110 is removed from the holding pins 415 via the door 180 and removed from the RTP chamber 105.

[0074] Aspects of the present invention have been discussed with reference to a rotatable support plate. Those of ordinary skill in the art will appreciate from the present description that, within the scope of the present invention, exemplary aspects of the present invention may be implemented with a stationary support plate. For example, one or more coherent light sources may be positioned with respect to a support pin on the stationary support plate. The coherent light source may emit coherent light onto the stationary support plate and through the support pin to reduce a cold spot on the workpiece.

Claims

[1] Thermal processing device (100, 400), comprising: a plurality of heat sources (130, 140) configured to heat a workpiece (110), a rotatable support plate (120, 410, 700) operable to support the workpiece (110) during thermal processing, the rotatable support plate (120, 410, 700) comprising: a light-transmissive support structure (115) configured to come into contact with the workpiece (110), the light-transmissive support structure (115) having a first end (212) and a second end (214), the first end (212) of the support structure being configured to support the workpiece (110); and a light source (430) operable to emit coherent light through the light-transmissive support structure (115) such that the coherent light (435) heats a portion of the workpiece (110) in contact with the light-transmissive support structure (115); wherein the light-transmissive support structure (115) has a plurality of support pins (210, 415); and the light-transmissive support structure (115) has a base (135, 230, 420), wherein the base (135, 230, 420) has a semi-annular opaque portion (520) arranged between at least two of the plurality of support pins (210, 415), wherein the semi-annular opaque portion (520) is configured to prevent the coherent light (435) of the light source (430) from heating the workpiece (110). [2] The thermal processing apparatus (100, 400) of claim 1, wherein the light-transmissive support structure (115) is configured to transfer heat from the plurality of heat sources (130, 140) to the workpiece (110). [3] The thermal processing device (100, 400) of claim 1, wherein the light-transmissive support structure (115) comprises a quartz material. [4] The thermal processing apparatus (100, 400) of claim 1, wherein the light source (430) is configured to be held stationary relative to the rotatable support plate (120, 410, 700) during rotational movement of the rotatable support plate (120, 410, 700) during thermal processing of the workpiece (110). [5] The thermal processing apparatus (100, 400) of claim 1, wherein the light source (430) comprises a laser. [6] The thermal processing device (100, 400) according to claim 1, wherein a width of the semi-annular opaque portion (520) is not smaller than a diameter of a contact area of the coherent light (435) in contact with the base (135, 230, 420). [7] The thermal processing device (100, 400) of claim 1, wherein the semi-annular opaque portion (520) comprises a wavelength-selective coating on a second surface of the base (135, 230, 420). [8] The thermal processing apparatus (100, 400) of claim 1, further comprising a control unit (175) configured to synchronize an emission of the coherent light (435) from the light source (430) with a movement of the base (135, 230, 420) such that the light source (430) emits the coherent light (435) into one of the plurality of support pins (210, 415) and onto the workpiece (110) when one of the plurality of support pins (210, 415) passes the light source (430) during the rotational movement of the support plate (120, 410, 700), and such that the light source (430) interrupts the emission of the coherent light (435) when one of the plurality of support pins (210, 415) is not arranged in front of the light source (430). is.

Images