System and method for controlling surface profile of sheet wafer in wire saw

Abstract

The invention relates to a system and a method for controlling a surface profile of a sliced wafer in a wire saw. The systems and methods are generally operable to alter the nanotopology of a wafer sliced from an ingot by controlling the shape of the wafer. For example, the shape of the wafer is changed by changing the temperature of a temperature control fluid circulating in fluid communication with a sidewall attached to a fixed bearing sidewall of the wire saw.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 365,921, filed on June 6, 2022, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to wire saw machines for slicing ingots into wafers, and more particularly to systems and methods for controlling the surface profile of sliced ​​semiconductor wafers in a wire saw machine. Background Art

[0004] Semiconductor wafers, such as silicon wafers, are typically sliced ​​from ingots using a wire saw. These ingots are typically made of silicon or other semiconductor or solar grade materials. In operation, the ingot is contacted by a moving wire web tensioned on bearings and rollers in the wire saw, which slices the ingot into multiple wafers. Wafers cut by known saws may have surface defects that cause the wafer to have a nanotopology that deviates from a set standard. In order to improve the deviated nanotopology, such wafers may be subjected to additional processing steps. These steps are time consuming and costly.

[0005] Surface defects formed during cutting of the ingot may occur at least in part due to thermal deformation of the wire saw assembly. The sidewalls of the support rollers may deform or expand during the cutting process, resulting in relative movement of the tensioned wire. The cutting process may take several hours to complete, resulting in a temperature increase over time, with the largest temperature increase occurring during the first few hours of the cutting operation. Controlling the deformation of the sidewalls during the cutting operation may reduce surface defects in the cut wafers.

[0006] Furthermore, known wire saw machines are not operable to adjust for the shape and / or deformation of the surface of wafers cut from an ingot by the machine.Therefore, a more efficient and effective system is needed to control the nanotopology of wafers cut in a wire saw machine.

[0007] This section is intended to introduce the reader to various aspects of the art that may be related to various aspects of the present disclosure described and / or claimed below. It is believed that this discussion is helpful in providing the reader with background information to facilitate a better understanding of various aspects of the present invention. Therefore, these statements should be read in this light, and not as an admission of prior art. Summary of the invention

[0008] In one aspect, a system for controlling the surface profile of a wafer sliced ​​from an ingot in a wire saw is disclosed. The system includes a wire saw base including a fixed bearing sidewall and a free bearing sidewall opposite the fixed bearing sidewall. A wire guide assembly supports a wire, and the wire guide assembly includes a roller having a first end connected to the fixed bearing sidewall and a second end supported by the free bearing sidewall. The wire guide rotates on a bearing, wherein thermal deformation of the fixed bearing sidewall from a first state to a second state corresponds to a change in a cut surface profile of a cut wafer from a first cut surface profile to a second cut surface profile. A temperature regulation system is attached to the fixed bearing sidewall for controlling the thermal deformation of the fixed bearing sidewall. A control system for controlling the temperature of the fixed bearing sidewall includes a temperature sensor for measuring the temperature of the fixed bearing sidewall. A processor is connected to the temperature regulation system and the control system, and the processor is configured to control the temperature of the fixed bearing sidewall at a desired temperature by activating the temperature regulation system.

[0009] Another aspect is a system for controlling a cut surface profile of a wafer cut from an ingot by a wire saw. The system includes a temperature regulation system of a fixed bearing sidewall attached to a wire saw base for controlling thermal deformation of the fixed bearing sidewall. A control system for controlling the temperature of the fixed bearing sidewall includes a temperature sensor for measuring the temperature of the fixed bearing sidewall and a displacement sensor for measuring thermal deformation of the fixed bearing wall. A processor is connected to the temperature regulation system and the control system, the processor being configured to control the temperature of the fixed bearing sidewall at a desired temperature by activating the temperature regulation system.

[0010] In another aspect, a method of slicing an ingot into wafers using a wire saw is disclosed. The method includes receiving input from a user, the input including a desired wafer surface profile corresponding to a temperature set point of a fixed bearing sidewall of a wire saw base; activating a temperature regulation system attached to the fixed bearing sidewall for controlling thermal deformation of the fixed bearing sidewall, the thermal deformation of the fixed bearing sidewall corresponding to the desired wafer surface profile; and initiating a slicing operation such that a wire supported by a wire guide assembly cuts wafers from the ingot, the wire guide assembly including a roller having a first end connected to the fixed bearing sidewall and a second end supported by a free bearing sidewall of the wire saw base, wherein the wire guide rotates on a bearing, wherein the thermal deformation of the fixed bearing sidewall from a first state to a second state corresponds to a change in a cutting surface profile of the cut wafer from a first cutting surface profile to a second cutting surface profile.

[0011] There are various refinements of the features described in connection with the aforementioned aspects. Further features may also be incorporated into the aforementioned aspects. These refinements and additional features may exist alone or in any combination. For example, various features discussed below with respect to any of the illustrated embodiments may be incorporated into any of the aforementioned aspects alone or in any combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a perspective view of a system including an ingot and a wire saw machine;

[0013] Figure 2 yes Figure 1 An end view of the system;

[0014] Figure 3 yes Figure 1 Left side view of the system;

[0015] Figure 4 yes Figure 1 Perspective view of a jigsaw machine.

[0016] Figure 5 is a side view of a temperature regulation system according to an embodiment of the present disclosure.

[0017] Figure 6 yes Figure 5 Front view of the temperature regulation system.

[0018] Figure 7 is a side view of a temperature regulation system according to an embodiment of the present disclosure.

[0019] Figure 8 yes Figure 7 Front view of the temperature regulation system.

[0020] Fig. 9 is a side view of a temperature regulation system according to an embodiment of the present disclosure.

[0021] Fig. 10A yes Fig. 9 Front view of the temperature regulation system.

[0022] Fig. 10B According to the embodiment of the present disclosure Fig. 9 Front view of the temperature regulation system.

[0023] Fig.11 is a block diagram of a processor according to an embodiment.

[0024] Fig.12 is a block diagram of a method according to an embodiment.

[0025] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0026] Refer to the diagram, Figure 1 An example system for controlling the surface profile of wafers cut from an ingot 102 by a wire saw machine 103 is shown in , and generally indicated at 100. As used herein, the term "surface profile" or "wafer surface profile" refers to both the nanotopology and shape of the wafer surface.

[0027] The systems and methods described herein are generally operable to control the shape of a wafer sliced ​​from an ingot by controlling the shape of the wafer, and thus the nanotopology. The shape of the wafer can be controlled by controlling the temperature of a wire saw sidewall to which a bearing is attached. The bearing supports the wire guide of the saw. The temperature of at least one of the walls of the wire saw base is controlled by a temperature regulation system attached to the fixed bearing sidewall or both of the sidewalls of the wire saw bar for controlling thermal deformation of the sidewall. Different feedback systems can be used to determine the temperature of the sidewall, and the deformation of the sidewall required to produce a wafer with a desired shape and / or nanotopology, although such feedback systems are not required. Nanotopology is defined as the deviation of the wafer surface within a spatial wavelength of about 0.2 mm to about 20 mm. This spatial wavelength is very close to the nanoscale surface features of processed semiconductor (e.g., silicon) wafers. The foregoing definition was proposed by Semiconductor Equipment and Materials International (SEMI), a global trade association for the semiconductor industry (SEMI document 3089). Nanotopology measures the height deviation of one surface of the wafer, rather than taking into account the thickness variation of the wafer as conventional flatness measurements do. Several measurement methods have been developed to detect and record these types of surface variations. For example, the measured deviation of reflected light from incident light allows detection of very small surface variations. These methods are used to measure peak-to-valley (PV) variations within a wavelength. Nanotopology can be predicted or estimated based on measurements of the wafer surface after the wafer is sliced ​​but before it is subjected to polishing.

[0028] The wire saw 103 (i.e., wire saw machine) is of a type used to slice (i.e., cut or saw) the ingot 102 into wafers using a wire mesh 104. The ingot 102 is connected to a bonding beam 101, which in turn is connected to a clamping rail 105. The clamping rail 105 is connected to the wire saw 103. When the ingot 102 is sliced, the wire mesh 104 (in Figure 2 Best in Show, Figure 3 The end view of FIG. 1 shows only one of the wires (shown in FIG. 1 ) follows a circuitous path around three wire guides 106. For clarity, Figure 2 The number of wires 104 shown in FIG. 1 is greatly reduced, and their spacing is also greatly exaggerated for clarity. One or more of the wire guides 106 may be connected to a drive source to rotate the guides, and in turn, the wire web 104.

[0029] In an example embodiment, the wire saw 103 is used to slice an ingot 102 made of a semiconductor material (eg, silicon) or a photovoltaic material. The wire saw 103 may also be used to slice an ingot of other materials into wafers.

[0030] The wire guide 106 has opposite ends 108, 110, each of which is connected to a frame 112 (106) of the wire saw 103 by a bearing 114. Figure 2 Only a portion thereof is shown in FIG. 1 ). The frame 112 includes a fixed bearing side wall 180 and a free bearing side wall 182 opposite to the fixed bearing side wall 180 .

[0031] Each bearing 114 of the fixed bearing side wall 180 has a rotating race 116 connected to the corresponding end 108 of the wire guide 106 and a fixed race 118 connected to the fixed bearing side wall 180. The rotating race 116 is Figure 3 1. The rotating race 116 rotates as the wire guide 106 to which it is connected rotates. Likewise, the fixed race 118 does not move significantly as the rotating race 116 and the wire guide 106 rotate. In the example embodiment, the bearing 114 is a typical roller bearing, although in other embodiments it can be any other suitable type of bearing (e.g., a roller bearing).

[0032] like Figure 4 , the frame 112 may be thermally deformed during the cutting process. Thermal deformation of the frame 112 changes the surface profile, resulting in surface defects of the cut ingot. Because the wire guide 106 is connected to the fixed bearing sidewall 180, but is movable relative to the free bearing sidewall 182, the wire guide 106 is less deflected due to thermal deformation of the free bearing sidewall 182. In other words, the first state is defined by the frame 112 and the sidewalls (180, 182) without thermal deformation, and the second state is defined by the frame 112 under thermal deformation of the fixed bearing sidewall 180. The ingot cut in the first state may have a different surface profile than the ingot cut in the second state. As explained in further detail below, the temperature adjustment system 200 may be attached to the fixed bearing sidewall 180 for controlling or reducing thermal deformation of the fixed bearing sidewall 180 by adjusting the temperature of the fixed bearing sidewall 180. In some embodiments, the temperature adjustment system 200 may also be attached to the free bearing sidewall 182 to adjust the temperature of the free bearing sidewall 182. The embodiments of the temperature regulation system 200 discussed below may be attached to the fixed bearing sidewall 180 , the free bearing sidewall 182 , or both.

[0033] While the primary function of the temperature regulation system 200 is to reduce thermal expansion of the fixed bearing sidewall 180, and thus reduce its deflection, in some embodiments, the temperature regulation system 200 can also be configured to selectively increase the temperature of the fixed bearing sidewall 180, as explained in further detail below. Because the temperature regulation system 200 can selectively thermally deform either wall, surface profile variations caused by external and uncontrolled sources can be corrected by the operation of the temperature regulation system 200.

[0034] Figure 5 A side view illustrating heat exchanger 210 of temperature regulation system 200 positioned on interior surface 202 of stationary bearing sidewall 180 . Figure 6 A front view of a heat exchanger 210 positioned on the outer surface of the fixed bearing sidewall 180 is illustrated. The heat exchanger 210 may be positioned near the area most susceptible to thermal deformation, and the heat exchanger 210 may be connected to more heat exchangers 210 on the inner surface 202. The heat exchanger 210 is suitably a Peltier cooler, a thermoelectric cooler module, or a solid-state heat pump. In some embodiments, the heat exchanger 210 includes a high thermal conductivity heat plate adjacent to the inner surface 202, and the reservoir 206 is adjacent to the heat plate. The reservoir 206 may have a fluid passing through it to promote heat transfer from the heat plate to the inner surface 202. In some embodiments, a fluid conduit 212 may connect multiple heat exchangers 210 to an external reservoir 206 (not shown) to define a fluid circuit. In some embodiments, the fluid circuit includes a valve or pump connected to a processor, as explained in further detail below. In some embodiments, the heat exchanger 210 is a cooling jacket.

[0035] The heat exchanger 210 may also be retrofitted onto an existing frame 112. By way of example, the heat exchanger 210 may be secured to the inner surface 202 of the fixed bearing sidewall 180 and connected to an external reservoir 206 and a valve or pump. In some embodiments, the inner surface 202 of the fixed bearing sidewall 180 may include a slot sized to receive the heat exchanger 210 such that the heat exchanger 210 is substantially flush with the inner surface 202 of the fixed bearing sidewall 180, thereby reducing the footprint of the heat exchanger 210.

[0036] Figures 7 to 10B An embodiment of the fluid channel 220 of the temperature regulation system 200 is illustrated. Figures 9 to 10B The fluid passages 220 illustrated as being internal (or within) the stationary bearing wall 180 and the fluid passages 220 illustrated as being external to the stationary bearing wall 180 are positioned on the inner surface 202 of the stationary bearing sidewall 180 . Figure 7 and 9 A front view illustrating the fluid passage 220 positioned on the inner surface 202 of the fixed bearing sidewall 180 .

[0037] like Figure 8As best shown in FIG. 1 , the fluid passage 220 may be internal to or embedded in the fixed bearing wall 180. Fig. 10A As best shown in FIG. 1 , the fluid passage 220 may be disposed on the inner surface 202 of the fixed bearing sidewall 180 and oriented proximate to the wire guide 106 and as Fig. 10B As best shown in FIG. 1 , the fluid passage 220 may be disposed on an outer surface 203 of the fixed bearing sidewall 180 , the outer surface 203 being opposite the inner surface 202 .

[0038] The fluid channel 220 may be positioned near the area most susceptible to thermal deformation. Figure 7 As best shown in FIG. 1 , in some embodiments, the fluid channels 220 may follow a series or parallel path, and as Fig. 9 As best shown in FIG. 2 , the fluid channel 220 may include a single channel. The fluid channel 220 may be connected to an external reservoir 206 (not shown) to define a fluid circuit. In some embodiments, the fluid circuit includes a valve or pump connected to a processor, as explained in further detail below.

[0039] The fluid channel 220 can also be retrofitted to an existing frame 112. For example, the fluid channel 220 can be fixed to the inner surface 202 of the fixed bearing side wall 180 and connected to an external reservoir 206 and a valve or pump, such as Fig. 9 10. In some embodiments, the inner surface 202 of the fixed bearing sidewall 180 may include a groove configured to receive the fluid channel 220, so that the fluid channel 220 is substantially flush with the inner surface 202 of the fixed bearing sidewall 180, thereby reducing the footprint of the fluid channel 220.

[0040] A temperature control fluid (interchangeably referred to as “fluid”) is in thermal communication with the temperature regulation system 200 such that the fluid contacts at least a portion of the stationary bearing sidewall 180 .

[0041] In an example embodiment, the fluid conduit 212 receives fresh fluid from the reservoir 206. The fluid conduit 212 may be a pipe, a hose, or other suitable structure (not shown).

[0042] A displacement sensor 130 (broadly, a "sensor") is disposed adjacent to the rotating race 116 for measuring movement and / or axial displacement of the race. Similarly, another displacement sensor 132 may be disposed adjacent to the fixed race 118 for measuring displacement of the race. In other embodiments, one of these sensors 130, 132 may be omitted. In an example embodiment, these sensors 130, 132 measure the axial displacement of the respective races 116, 118 and are non-contact sensors. In other embodiments, the sensors 130, 132 may be configured and / or positioned differently to measure different types of movement of the bearing 114. The sensors 130, 132 communicate with a processor 140 (discussed in more detail below) via any suitable communication system (e.g., a wired and / or wireless network).

[0043] For clarity, only one of each sensor 130, 132 is shown in the figure, although in the example embodiment, each race of each bearing 114 in thermal communication with the fluid has such a sensor. In other embodiments, the sensors 130, 132 may be positioned adjacent to different bearings 114 or portions thereof to measure the displacement of the respective bearings or portions thereof.

[0044] The temperature sensor is arranged to be in thermal communication with the fluid to measure its temperature. In the example embodiment, the temperature sensor 134 is positioned adjacent to the rotating seat 116, and the temperature sensor 136 is positioned adjacent to the fixed seat 118. Therefore, the temperature sensors 134, 136 are positioned adjacent to each seat that is thermally connected to the fluid, and the fluid is in thermal communication with the corresponding seat. Since the fluid in these positions is thermally connected to the corresponding seat 116, 118, the temperature of the fluid indicates the temperature of the seat. In the example embodiment, it is assumed that the temperature of the fluid adjacent to the corresponding seat 116, 118 is generally equal to the temperature of the seat. In other embodiments, this may not be the case, and the temperature of the fluid adjacent to the seat 116, 118 is different from the temperature of the seat. A high flow rate of the fluid is applied to the system so that the temperature of the fluid running through the corresponding seat 116, 118 is maintained at an equal value. Due to the heat absorbed by the temperature regulation system 200, a low flow rate will result in a temperature difference at the system inlet relative to the system outlet.

[0045] The temperature sensors 134, 136 are communicatively coupled to the processor 140 via any suitable communication system (e.g., a wired and / or wireless network) (discussed in more detail below). Figure 2 and 3A processor, schematically shown in FIG. 1 and generally indicated at 140, is communicatively connected to the temperature sensors 134, 136, the displacement sensors 130, 132, and the temperature regulation system 200. Typically, and as discussed in more detail below, the processor 140 is configured to receive input from a user identifying a desired wafer nanotopology profile or shape of a wafer sliced ​​from an ingot. Alternatively, the processor 140 is configured to maintain the temperature at a set level to reduce deformation. Based on this input and the measured temperature of the fluid, the processor 140 communicates instructions to the temperature regulation system 200 to control (i.e., adjust, alter, or change) the temperature of the fluid.

[0046] The flow rate is typically kept constant. The temperature of the fluid can be controlled by activating a heater or cooler (not shown) connected to the reservoir 206. The reservoir 206 has a sufficient volume so that the fluid circulating through the reservoir 206 is uniformly heated or cooled. Alternatively, the fluid may be partially drained from the reservoir 206 and fresh fluid may be added to the reservoir 206. The fresh fluid has a target temperature so that the reservoir 206 reaches the target temperature.

[0047] Changes in the temperature of the fixed bearing sidewall 180 alter its displacement and the displacement of the wire guide 106 and wire 104. Control of the displacement of the wire guide 106 and wire 104 controls the shape of the wafer surface, which in turn controls the nanotopology of the surface.

[0048] The operation of the processor 140 and the system 100 is now described in more detail. An input device 160, as shown in FIG. 13 , is communicatively connected to the processor 140 and may be used to receive input from a user identifying a desired wafer nanotopology or wafer shape. In other embodiments, the processor 140 may receive this input from another computer system communicatively connected to the processor.

[0049] Once the processor 140 receives this input, the processor retrieves a recipe associated with the input from the memory 150. The memory will be described in more detail below. The recipe specifies a temperature set point (i.e., a desired temperature) for the fixed bearing sidewall 180 and / or a temperature control fluid associated with the recipe. In addition to or in lieu of the temperature set point for the bearing and / or fluid, the recipe may also include a displacement measurement of the bearing. During cutting of the ingot 102 by the saw 103, adhering to the temperature and / or displacement measurements contained in the recipe generally produces wafers having the same or similar characteristics as the input. The recipes may be interchangeably referred to as "temperature profiles," "displacement profiles," and / or "temperature-displacement profiles." The processor sends a signal to activate a heater or cooler connected to the storage 206.

[0050] The recipes may be established according to a variety of methods. The specific temperatures and / or displacements for each recipe may be determined experimentally (i.e., during a previous slicing operation) or empirically based on the material properties of the bearing 114 (i.e., the coefficient of thermal expansion of the bearing material). In one embodiment, the recipes are established experimentally by measuring the temperature of the fluid, the bearing, and / or the displacement of the bearing 114 during slicing of the ingot 102 and storing these measurements in the memory 150. The surface of at least one wafer is then measured, and the characteristics of the shape and / or nanotopology of the wafer are then stored in the memory 150. Together with the temperature measurements and / or displacement measurements, these characteristics of the wafer form the recipe. As described below, this process can also be used to periodically update the recipe.

[0051] As described above, in an example embodiment, the temperature of the bearing 114 is generally equal to the temperature of the temperature control fluid in thermal communication with the bearing. The recipe is associated with the input, such that the system's use of the recipe will result in wafers sliced ​​by the saw 103 having the desired nanotopology and / or input shape. These recipes are stored in a memory 150 that is communicatively connected to the processor 140. This memory 150 is any suitable form of computer-readable media, including tangible storage devices (e.g., hard drives, flash memory, optical drives, etc.).

[0052] These temperatures of the fluid will result in changes in the position of the bearing 114 due to changes in the fixed bearing sidewall 180 , which will result in the wafers sliced ​​by the saw having the desired nanotopology and / or shape. In an example embodiment, the processor 140 retrieves the temperature set points from the memory 150 .

[0053] In operation, the saw 103 then begins slicing the ingot 102, and the processor 140 communicates instructions to the temperature regulation system 200 to adjust the temperature of the fluid in the reservoir 206 based on the temperature set point and the measured temperature of the fluid. For example, the processor 140 may be connected to a heater or cooler (not shown). Once the temperature of the fluid equals the temperature of the temperature set point, the processor 140 sends instructions to the heater or cooler to stop adjusting the temperature of the fluid. The processor 140 may continue to monitor the temperature measurements received from the temperature sensors 134, 136.

[0054] Controlled deformation of the fixed bearing sidewall 180 may be achieved by heating or cooling only one surface of the fixed bearing sidewall 180. The processor 140 may be connected to a pump or valve (204) to shut off or throttle flow of the heat exchanger 210 to the inner or outer surface of the fixed bearing sidewall 180.

[0055] Temperature changes in the fixed bearing sidewall 180 caused by changes in fluid flow rate alter its displacement and the displacement of the wire guide 106 and wire 104. Control of the displacement of the wire guide 106 and wire 104 controls the surface shape of the wafer, which in turn controls the nanotopology of the surface.

[0056] The fluid may be chilled plant water at a relatively constant temperature (eg, between about 5°C and about 10°C) obtained from a reservoir 206 or other source prior to circulating contact with the fixed bearing sidewall 180. After contact with the bearing, the fluid returns to the reservoir 206.

[0057] Temperature sensors 134, 136 are adapted to measure the temperature of the fluid and / or the stationary bearing sidewall 180. The temperature regulation system 200 described above may be used to control the temperature of the fluid, and the recipe may include a temperature set point for the bearing in addition to a temperature set point for the fluid.

[0058] The temperature set point may also be determined based on the measured displacement of the fixed race 118 and / or the rotating race 116 of the bearing 114. For example, if the measured displacement of the fixed bearing sidewall 180 is within the displacement range specified by the recipe, the temperature set point may be adjusted so that the temperature of the fluid in thermal communication with the fixed bearing sidewall 180 and / or the flow rate of the fluid does not change. The measured displacement of the fixed bearing sidewall 180 may thus be used as feedback to the processor to adjust the temperature set point.

[0059] After the slicing operation, the recipe or process can be updated by measuring the surface of the wafer sliced ​​from the ingot. For example, the surface of the wafer can be measured and compared to the desired wafer shape and / or nanotopological profile input by the user. If the measured value of the surface is different from the measured value input by the user, the recipe can be updated. This update can include adjusting the temperature set point of the fluid included in the recipe and / or the flow rate of the fluid. The update can also include an adjustment of the desired displacement of a portion of the fixed bearing sidewall 180.

[0060] In another embodiment, the displacement of the fixed bearing sidewall 180 is measured at set intervals by the displacement sensors 130, 132 during slicing of the ingot 102. The displacement measurements are then received by the processor 140. In response to the received measurements, the processor 140 determines a temperature set point for the fixed bearing sidewall 180 that is necessary to reduce or eliminate its displacement and ameliorate the negative effects that such displacement may have on the wafers.

[0061] The processor 140 then communicates instructions to the temperature regulation system 200 to control the temperature of the fluid based at least in part on the measured displacement of the fixed bearing sidewall 180. In embodiments using a valve 204, the processor 140 may also communicate instructions to a heater or cooler to control the temperature of the fluid. These instructions to the valve 204 are also based at least in part on the measured displacement of the fixed bearing sidewall 180. The combined effect of the temperature regulation system 200 and the temperature control of the reservoir 206 controls the temperature of the fixed bearing sidewall 180, which in turn controls the displacement of the fixed bearing sidewall 180. In addition, the instructions generated by the processor 140 may also be based at least in part on one or more recipes stored in the memory 150.

[0062] In one example, the processor 140 may determine a temperature set point based on the measured displacement of the fixed bearing sidewall 180 or a portion thereof. The processor then communicates instructions to the temperature regulation system 200 to cool the fluid based on the measured displacement of the fixed bearing sidewall 180 or a portion thereof. The reduction in the temperature of the fluid reduces the temperature of the fixed bearing sidewall 180, which in turn reduces or eliminates its displacement. The temperature sensors 134, 136 may also be used to measure the temperature of the fluid and / or the fixed bearing sidewall 180 and communicate these temperature measurements to the processor 140. These temperature measurements are used as feedback for the processor 140.

[0063] In another example, during slicing of the ingot 102, only the temperature of the fluid is controlled, without measuring the displacement of the fixed bearing sidewall 180. In these embodiments, the temperature regulation system 200 controls the temperature of the fluid to control the temperature of the fixed bearing sidewall 180 according to a temperature set point. This temperature set point can be retrieved from a recipe as described above. Alternatively, it can be received as an input to the system 100 from a user or other computer system. In some embodiments, the system 100 can measure the temperature of the fluid with the respective sensors 134, 136, and use the measured values ​​as feedback to control the temperature regulation system 200.

[0064] A method for slicing an ingot into wafers using a wire saw Fig.12300. The method includes receiving 302 an input from a user, the input including a desired wafer surface profile corresponding to a temperature set point of a fixed bearing sidewall of a wire saw frame; activating 304 a temperature regulation system attached to the fixed bearing sidewall for controlling thermal deformation of the fixed bearing sidewall, the thermal deformation of the fixed bearing sidewall corresponding to the desired wafer surface profile; and initiating 306 a slicing operation such that a wire supported by a wire guide cuts a wafer from an ingot, the wire guide assembly including a roller having a first end connected to the fixed bearing sidewall and a second end supported by a free bearing sidewall of the wire saw frame, wherein the wire guide rotates on a bearing, wherein the thermal deformation of the fixed bearing sidewall from a first state to a second state corresponds to a change in a cutting surface profile of the cut wafer from a first cutting surface profile to a second cutting surface profile. In some embodiments, the method 300 further includes maintaining 308 a temperature of the fixed bearing sidewall at a first desired temperature, the first desired temperature corresponding to a first cutting surface profile of the cut wafer. In some embodiments, the method further includes increasing 310 a temperature of the fixed bearing housing to a second desired temperature, the second desired temperature corresponding to a second cutting surface profile of the cut wafer.

[0065] The method may also include reducing the temperature of the fixed bearing housing to a third desired temperature, the third desired temperature corresponding to a third cut surface profile of the cut wafer. The method may further include retrieving, by a processor, the wafer surface profile from a memory, wherein the processor is configured to communicate instructions to a control system to control a temperature regulation system. In some embodiments, the method further includes activating a valve of the temperature regulation system for controlling the temperature of the fixed bearing sidewall.

[0066] The described systems and methods control the nanotopology and shape of wafers cut in a wire saw machine 103. It has been determined that in previous systems, the fixed bearing sidewall 180 or portions thereof may undergo displacement or movement during slicing of the ingot 102. This displacement of the fixed bearing sidewall 180 may remain relatively constant during slicing of the ingot 102 by the wire saw 103. However, the displacement of the rotating race 116 is noticeable. Due to the deformation of the fixed bearing sidewall 180, this displacement of the bearing 114 causes displacement of the wire guide 106 and wire 104 of the saw 103. The displacement of the wire guide 106 and wire 104 in turn causes defects in the shape and / or nanotopology of the wafers sliced ​​from the ingot 102. The entry and exit marks are types of such defects. The displacement of the bearing 114 may be caused by temperature changes of the fixed bearing sidewall 180, and therefore by temperature changes of the fluid in thermal communication with the fixed bearing sidewall 180.

[0067] By controlling the temperature of the fluid in contact with the fixed bearing sidewall 180, the systems and methods described herein control the temperature of the fixed bearing sidewall 180. Control of the temperature of the fixed bearing sidewall 180 in turn controls its displacement. Thus, the displacement of the fixed bearing sidewall 180 can be minimized or eliminated by controlling its temperature. By this, the displacement of the wire guide 106 and the wire 104 can also be minimized or eliminated. Thus, defects in the shape of the wafer and / or its nanotopology (e.g., entry or exit marks) can be reduced or eliminated. This reduction in defects increases the yield of the wafer manufacturing process. In addition, the duration of downstream processing operations (e.g., grinding) can be reduced or eliminated, thereby reducing the time and cost of manufacturing wafers.

[0068] In addition to reducing or eliminating other defects (e.g., entry or exit marks), the systems and methods can also control the shape and / or nanotopology of the wafer. Thus, a user can input a predetermined shape and / or nanotopology profile of a wafer sliced ​​from the ingot 102. For various reasons, a user may desire a wafer with a different shape and / or nanotopology.

[0069] When introducing elements of the present disclosure or embodiments thereof, the articles “a,” “an,” and “the,” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0070] As various changes could be made in the above without departing from the scope of the present disclosure, it is therefore intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting.

Claims

1. A system for controlling the surface profile of wafers sliced ​​from an ingot in a wire saw, comprising: A wire saw base, comprising a fixed bearing side wall and a free bearing side wall opposite to the fixed bearing side wall; a wire guide assembly for supporting a wire, the wire guide assembly comprising a roller having a first end connected to the fixed bearing sidewall and a second end supported by the free bearing sidewall, wherein the wire guide rotates on the bearing, wherein thermal deformation of the fixed bearing sidewall from a first state to a second state corresponds to a change in a cutting surface profile of a cut wafer from a first cutting surface profile to a second cutting surface profile; a temperature regulation system attached to the fixed bearing sidewall for controlling thermal deformation of the fixed bearing sidewall; a control system for controlling the temperature of the fixed bearing side wall, comprising a temperature sensor for measuring the temperature of the fixed bearing side wall; and A processor is connected to the temperature regulation system and the control system, the processor being configured to control the temperature of the fixed bearing side wall to a desired temperature by activating the temperature regulation system.

2. The system of claim 1, wherein the processor is configured to maintain a temperature of the fixed bearing sidewall at a first desired temperature corresponding to the first cut surface profile of the cut wafer.

3. The system of claim 1, wherein the processor is configured to increase the temperature of a fixed bearing housing to a second desired temperature corresponding to the second cut surface profile of the cut wafer.

4. The system of claim 1, wherein the processor is configured to reduce the temperature of the fixed bearing housing to a third desired temperature corresponding to a third cut surface profile of the cut wafer.

5. The system of claim 1 , wherein the control system further comprises a memory for storing temperature profiles, each temperature profile being associated with a cutting surface profile and defining a temperature set point for the fixed bearing sidewall, the processor being configured to retrieve the associated temperature set point from the memory, the processor being configured to communicate instructions to the control system to control the temperature regulation system.

6. The system of claim 1, wherein the temperature regulation system comprises a fluid channel and a valve fluidly connected to the fluid channel, the processor is connected to the valve, and the processor is configured to maintain the temperature of the fixed bearing sidewall at a desired level by activating the valve.

7. The system of claim 6, wherein the fluid passage is interior to the fixed bearing sidewall.

8. The system of claim 7, wherein the fluid passage is on an inner surface of the fixed bearing sidewall.

9. The system of claim 6, wherein the fluid passage is on an outer surface of the fixed bearing sidewall.

10. The system of claim 1, wherein the temperature regulation system includes a heat exchanger, the processor is communicatively coupled to the heat exchanger, the processor being configured to maintain the temperature of the fixed bearing sidewall at a desired temperature by activating the heat exchanger.

11. The system of claim 1 further comprising a sensor coupled to the fixed bearing sidewall for measuring thermal displacement of the fixed bearing sidewall.

12. The system of claim 1, wherein the control system is connected to a valve of the temperature regulation system for controlling a flow rate of a fluid of the temperature regulation system.

13. A system for controlling a cut surface profile of a wafer cut from an ingot by a wire saw, the system comprising: a temperature regulation system attached to a fixed bearing side wall of the wire saw base for controlling thermal deformation of the fixed bearing side wall; a control system for controlling the temperature of the fixed bearing side wall, comprising a temperature sensor for measuring the temperature of the fixed bearing side wall and a displacement sensor for measuring the thermal deformation of the fixed bearing wall; and A processor is in communication with the temperature regulation system and the control system, the processor being configured to control the temperature of the fixed bearing sidewall to a desired temperature by activating the temperature regulation system.

14. A method for slicing an ingot into wafers using a wire saw, the method comprising: receiving input from a user, the input comprising a desired wafer surface profile corresponding to a temperature set point of a fixed bearing sidewall of a wire saw base; activating a temperature regulation system attached to the fixed bearing sidewall for controlling thermal deformation of the fixed bearing sidewall, the thermal deformation of the fixed bearing sidewall corresponding to the desired wafer surface profile; and A slicing operation is initiated such that a wire supported by a wire guide assembly cuts wafers from the ingot, the wire guide assembly comprising a roller having a first end connected to the fixed bearing side wall and a second end supported by a free bearing side wall of the wire saw base, wherein the wire guide rotates on the bearing, wherein thermal deformation of the fixed bearing side wall from a first state to a second state corresponds to a change in a cutting surface profile of the cut wafer from a first cutting surface profile to a second cutting surface profile.

15. The method of claim 14, further comprising maintaining a temperature of the fixed bearing sidewall at a first desired temperature corresponding to the first cut surface profile of the cut wafer.

16. The method of claim 14, further comprising increasing the temperature of a stationary bearing housing to a second desired temperature corresponding to the second cut surface profile of the cut wafer.

17. The method of claim 14, further comprising reducing the temperature of the fixed bearing housing to a third desired temperature corresponding to a third cut surface profile of the cut wafer.

18. The method of claim 14, wherein wafer surface profiles are stored in a memory connected to a processor connected to the temperature regulation system, each of the wafer surface profiles being associated with a temperature set point for the fixed bearing sidewall.

19. The method of claim 18, further comprising retrieving, by the processor, a wafer surface profile from the memory, wherein the processor is configured to communicate instructions to a control system to control the temperature regulation system.

20. The method of claim 14, further comprising activating a valve of the temperature regulation system for controlling the temperature of the fixed bearing sidewall.

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