KR20140100549A

KR20140100549A - Systems and methods for controlling surface profiles of wafers sliced in a wire saw

Info

Publication number: KR20140100549A
Application number: KR1020147017760A
Authority: KR
Inventors: 카를로 자바타리; 페르난도 세베리코; 수미트 에스. 바가바트; 가브리엘레 베르셀로니; 롤랜드 알. 반다메
Original assignee: 엠이엠씨 일렉트로닉 머티리얼스 쏘시에떼 퍼 아찌오니
Priority date: 2011-12-01
Filing date: 2012-11-30
Publication date: 2014-08-14
Also published as: WO2013079683A1; KR20180125039A; TW201335982A; TWI567812B

Abstract

Systems and methods for controlling surface profiles of wafers cut in a wire saw machine are disclosed. The systems and methods described herein are generally operable to alter the nanotopology of sliced wafers from the ingot by controlling the shape of the wafers. The shape of the wafers is changed by changing the temperature and / or flow rate of the temperature control fluid circulating in contact with the bearings supporting the wire guides of the wire saw. Different feedback systems can be used to determine the temperature of the fluid needed to create wafers with the desired shape and / or nanoporosity.

Description

TECHNICAL FIELD [0001] The present invention relates to systems and methods for controlling surface profiles of sliced wafers in wire saws. BACKGROUND OF THE INVENTION [0002]

The present disclosure relates generally to wire saw machines used to slice ingots into wafers and more particularly to systems for controlling the surface profile of sliced wafers in wire saw machines, &Lt; / RTI >

Semiconductor wafers are typically formed by cutting ingots using wire saw machines. These ingots are sometimes made of silicon or other semiconductor or solar grade materials. The ingot is connected to the structure of the wire saw by a bond beam and an ingot holder. The ingot is bonded to the bond beam with an adhesive, and the bond beam is then bonded to the ingot holder using an adhesive. The ingot holder is connected to the wire saw structure by any suitable fastening system.

In operation, the ingot contacts the web of moving wires in the wire saw that slides the ingot into a plurality of wafers. The bond beam is then connected to a hoist and the wafers are dropped onto a cart.

The wafers cut by known saws may have surface defects that cause the wafers to have nanotopology deviations from the established specifications. To improve these deviating nanotopologies, these wafers may undergo additional processing steps. These steps are time consuming and costly. In addition, known wire softer machines are not operable to control the shape and / or warp of the surfaces of the wafers cut from the ingot by these machines. Thus, a more efficient and effective system needs to control the nanotopology of the wafers cut in the wire saw machine.

This part is intended to introduce the reader to various aspects of the technology that may be involved in the various aspects of the disclosure, which are described and / or claimed below. This discussion is likely to be useful in providing background information to the reader to better understand the various aspects of the present invention. Accordingly, it should be understood that these statements should be read at this level and not as prior art.

One aspect is a system for controlling a surface profile of sliced wafers from an ingot in a wire saw, the wire saw comprising a wire guide for supporting the wires, the wire guide being mounted on a bearing The wire saw comprising a fluid in thermal communication with the bearing. The system comprising: a memory for storing temperature profiles, each temperature profile associated with a surface profile and defining a temperature set point for at least one of the fluid and the bearing; A control system for controlling the temperature, a temperature sensor for measuring the temperature of at least one of the fluid and the bearing, and a processor communicatively coupled to the memory, the control system and the temperature sensor, Is configured to receive an input identifying a desired surface profile and to retrieve a temperature set point associated therewith from the memory, wherein the processor is configured to determine at least one of the temperature set point and the measured temperature of at least one of the fluid and the bearing On the basis of this, It is configured to transmit instructions to also to control of the control system.

Another aspect is a system for controlling the surface profile of wafers cut from ingots in wire saws. The system includes a wafer measurement sensor for measuring a surface of a wafer previously cut by the wire saw, a sensor arranged to measure displacement of a bearing of a wire guide supporting the wires in the wire saw, Wherein the processor is configured to determine the temperature set point based at least in part on one of a measured displacement of the bearing and a measured surface of the previously cut wafer, And is communicatively coupled to the wafer measurement sensor and the sensor.

Another aspect is a system for controlling the surface profile of sliced wafers from an ingot in a wire saw, the wire saw comprising a wire guide for supporting the wires, the wire guide rotating on a bearing, And includes a thermally communicating fluid. The system comprising: a memory for storing temperature profiles, each temperature profile associated with a surface profile and defining a temperature set point for the bearing; a valve for controlling the flow rate of the fluid; A temperature sensor for measuring the temperature of the bearing; and a processor communicatively coupled to the memory, the valve, and the temperature sensor, the processor receiving an input identifying a desired surface profile and associated temperature set point Wherein the processor is configured to transmit instructions to the valve to control a flow rate of the fluid based at least in part on the temperature set point of the bearing and the measured temperature.

Another aspect is a method of slicing a semiconductor or solar cell ingot into wafers using wire saws, the wire saw comprising a wire guide for supporting the wires, the wire guide rotating on a bearing, And a fluid in thermal communication with the bearing. The method includes receiving an input from a user including a desired wafer surface profile, selecting a temperature and displacement profile based on the input, initiating a slicing operation, measuring a displacement of the bearing Measuring at least one of a temperature of the bearing and a temperature of the fluid; measuring at least one of the measured displacement of the bearing, the selected temperature and displacement profile, and the measured temperature of at least one of the fluid and the bearing; Determining a temperature set point based at least in part on the temperature set point; and controlling a temperature of at least one of the fluid and the bearing based on the set temperature point.

Another aspect is a method of slicing an ingot into wafers using wire saws, the wire saw comprising a wire guide for supporting the wires, the wire guide rotating on a bearing and the wire saw being thermally And a fluid communicating therewith. The method includes receiving an input from a user including a desired wafer surface profile, selecting a recipe based on the desired surface profile, the recipe having a temperature profile defining a temperature set point for the fluid Controlling the temperature of the fluid based on the selected recipe, wherein controlling the temperature of the fluid includes controlling the temperature of the bearing, controlling the temperature of the fluid, And initiating a slicing operation.

Another aspect is a method of slicing an ingot into wafers using a wire saw, the wire saw comprising a wire guide for supporting the wires, the wire guide rotating on a bearing, And a valve for controlling the flow rate of the fluid. The method includes receiving an input from a user including a desired wafer surface profile, and selecting a recipe based on the input, wherein the recipe comprises at least one of a temperature profile and a displacement profile for the bearing Controlling the flow rate of the fluid based on the selected recipe, wherein controlling the flow rate of the fluid comprises controlling the flow rate of the fluid to control the temperature of the bearing , And initiating a slicing operation.

Another aspect is a method of controlling the surface profile of sliced wafers from ingots using wire saws. The method includes measuring a surface of a wafer previously cut by the wire saw, measuring a displacement of a bearing of the wire guide supporting the wires in the wire saw, measuring the displacement of the bearing Determining a temperature set point of the bearing based in part on at least one of the measured surfaces of the previously cut wafer; and controlling the temperature of the fluid circulating in contact with the bearing based on the temperature set point Wherein controlling the temperature of the fluid controls the temperature of the bearing and wherein controlling the temperature of the bearing controls the surface profile of the sliced wafers from the ingot using the wire saw, And controlling the temperature.

Another aspect is a method of controlling displacement of a bearing in a wire saw for slicing a semiconductor or solar charge ingot into wafers, wherein the wire saw includes a wire guide for supporting the wires, And the wire saw comprises a fluid in thermal communication with the bearing. The method includes measuring a displacement of the bearing, determining a temperature set point of the bearing based at least in part on the measured displacement of the bearing, and determining the temperature of the fluid based on the temperature set point And a flow rate, wherein controlling at least one of a temperature and a flow rate of the fluid includes controlling the displacement of the bearing.

Yet another aspect is a method of controlling displacement of a bearing in a wire saw for slicing an ingot into wafers. The method includes measuring a displacement of the bearing of a wire guide supporting wires in the wire saw, determining a temperature set point based at least in part on the measured displacement of the bearing, Controlling the temperature of the fluid circulating in contact with the bearing based on the point, wherein controlling the temperature of the fluid includes controlling the displacement of the bearing.

Another aspect is a system for controlling the surface profile of wafers cut from ingots in wire saws. The system includes a sensor arranged to measure a displacement of a bearing of a wire guide supporting wires in the wire saw and a processor communicatively coupled to the sensor and configured to determine a temperature set point for the bearing, Wherein the processor is configured to determine the temperature set point based at least in part on a measured displacement of the bearing, and wherein using the temperature set point in controlling the temperature of the bearing is performed by the wire saw from the ingot Thereby controlling the surface profile of the cut wafers.

Another aspect is a system for controlling the nanotopology of sliced wafers in a wire saw for slicing a semiconductor or solar cell ingot into wafers, wherein the wire saw includes a wire guide for supporting the wires, Rotates on a bearing and the wire saw comprises a fluid in thermal communication with the bearing. The system comprising: a sensor arranged to measure displacement of the bearing of the wire guide; and a processor configured to determine a temperature set point communicatively coupled to the sensor and used to control the temperature of the fluid, Is configured to determine the temperature set point based at least in part on a measured displacement of the bearing, wherein controlling the temperature of the fluid controls displacement of the bearing, and controlling the displacement of the bearing And a memory configured to be communicatively coupled to the processor and configured to store the temperature set points. &Lt; RTI ID = 0.0 > [0002] < / RTI >

Another aspect is a system for controlling the surface profile of sliced wafers in a wire saw for slicing a semiconductor or solar cell ingot into wafers, wherein the wire saw includes a wire guide for supporting the wires, Rotating on a bearing, said wire saw comprising a fluid in thermal communication with said bearing. The system comprising: a sensor arranged to measure displacement of the bearing of the wire guide; and a processor configured to determine a temperature set point communicatively coupled to the sensor and used in controlling the flow rate of the fluid, Wherein the processor is configured to determine the temperature set point based at least in part on a measured displacement of the bearing, wherein controlling the flow rate of the fluid controls displacement of the bearing, and wherein controlling the displacement of the bearing The processor controlling the surface profile of the wafers cut from the ingot by the wire saw and a memory communicatively coupled to the processor and configured to store the temperature set point.

There are various embodiments of the features mentioned in connection with the above-described aspects. Other features may also be included in the above-described aspects. These embodiments and additional features may be present individually or in any combination. For example, various features described below in connection with any illustrated embodiment may be included within any of the above aspects, alone or in any combination.

1 is a perspective view of a system including an ingot and wire soom.
Figure 2 is an end view of the system of Figure 1;
Figure 3 is a left side view of the system of Figure 1;
4 is a graph showing the relationship between the bearing displacement and the time when the ingot is cut by the wire saw machine.
5 is a graph showing the relationship between the bearing temperature and the bearing displacement.
6 is a graph showing the relationship between the bearing temperature and the wafer shape.
Corresponding reference characters indicate corresponding parts throughout the several views.

Referring to the drawings, an exemplary system for controlling the surface profile of wafers cut from an ingot 102 by a wire saw machine 103 is shown in FIG. 1 and generally designated by the reference numeral 100. As used herein, the terms "surface profile" or "wafer surface profile" refer to both the nanotopology and shape of the surfaces of the wafers.

The systems and methods used herein can control the shape of wafers sliced from the ingot and thereby the nanotopology by controlling the overall shape of the wafers. The shape of the wafers can be controlled by controlling the temperature of the bearings supporting the wire guides of the wire saw. The temperature of the bearings is controlled by controlling the temperature of the temperature-controlled fluid circulated in fluid communication with the bearing and / or by controlling the flow rate of the fluid. Different feedback systems may be used to determine the temperature of the fluid and / or the bearings needed to produce wafers having the desired shape and / or nanoporosity, but such a feedback system may not be required. Systems and methods can also be used to store and retrieve recipes that define a temperature profile and / or a displacement profile for fluid and / or bearings corresponding to desired surface profiles. Embodiments of the systems and methods described herein are operable to reduce or eliminate the entry mark and / or exit mark formed on the surfaces of the wafers cut in the wire softer machines.

The nanopolar was defined as the deviation of the wafer surface within a spatial wavelength of about 0.2 mm to about 20 mm. This spatial wavelength corresponds very closely to the surface features of the nanometer scale for the processed semiconductor wafers. The above provisions were proposed by Semiconductor Equipment and Materials International (SEMI), a global trade association for the semiconductor industry (SEMI document 3089). The nanopopoles measure the elevational deviation of one surface of the wafer as in conventional flatness measurements and do not take into account the wafer thickness variations. Several metrology methods have been developed for detecting and recording surface deviations of these kinds. For example, the measurement deviation of the reflected beam from the incident light allows detection of very small surface deviations. These methods are used to measure peak to valley (PV) changes in wavelength. The nano topology can be predicted or evaluated based on measurement measurements taken on the surface of the wafer after the wafer is sliced but before it is polished.

The outer well 103 (i.e., wire saw machine) is a type used to slice (i.e., cut or saw) the ingot 102 into wafers using the web of wires 104. The ingot 102 is connected to the bond beam 101 and the bond beam 101 is connected to the clamping rail 105. The clamping rail 105 is connected to the wire saw 103. The web of wires 104 (best shown in FIG. 2 and only one of the wires in the end view of FIG. 3 is shown) slides along the three wire guides 106 when slicing the ingot 102 Moves along a continuous path. The number of wires 104 shown in FIG. 2 has been greatly reduced for clarity and the spacing therebetween is greatly exaggerated for clarity as well. One or more of the wire guides 106 may be connected to a driving source that rotates the webs of these guides and thereby the wires 104. [

In an exemplary embodiment, wire saw 103 is used to slice ingots 102 made of a semiconductor material (e.g., silicon) or a photovoltaic material. The wire saw 103 may also be used to slice the ingots of different materials into the wafers.

In this embodiment, the wire guides 106 have opposing ends 108,110, each of which is secured to the frame 112 of the wire saw 103 by a bearing 114 Lt; / RTI > Each bearing 114 (only one shown for clarity) is connected to a rotating race 116 and a frame 112 connected to a respective end 108 of the wire guide 106 And a stationary race 118. Rotatable race 116 is best shown in Fig. As its name suggests, the rotatable race 116 rotates as the wire guide 106 to which the race is connected rotates. Likewise, the stationary race 118 does not move perceptibly as the rotatable race 116 and wire guide 106 rotate. In an exemplary embodiment, the bearing 114 is a conventional ball bearing, but in other embodiments the bearings may be any other suitable type of bearing (e.g., a roller bearing). The temperature-controlled fluid (which is interchangeably referred to as a "fluid") is in thermal communication with the bearings 114 that support each wire guide 106 so as to contact at least a portion of the bearing or a structure in contact with the bearing do.

In the exemplary embodiment, each stationary race 118 includes an inlet 120 for receiving fresh fluid from the heat exchanger 124 and an outlet 122 for discharging fluid from the race to the heat exchanger. Likewise, each rotatable race 116 includes an inlet 126 for receiving fresh fluid from the heat exchanger 124 and an outlet 128 for discharging fluid from the race to the heat exchanger. Inlets 120 and 126 and outlets 122 and 128 are connected to heat exchanger 124 using pipes, hoses, or other suitable structures (not shown). Only one inlet 120,126 for the bearing 114 and a set of outlets 122,128 are shown in the drawings for clarity. It should be understood that other bearings have the same or similar configuration and / or number of inlets and outlets. In the exemplary embodiments, only the bearings 114 on the left side of the system 100 are movable and the bearings on the right side are not movable. Thus, in the exemplary embodiment, the bearings 114 on the left side of the system 100 only receive significant displacements, and only their displacement can be adjusted. In other embodiments, this is not the case and the bearings 114 on both sides of the system 100 may be movable and / or their displacement adjusted. In addition, in some embodiments, the non-movable (i.e., fixed) bearings may receive some degree of displacement during use of the wire saw, so that their position is the same or similar to the methods and systems described herein And methods described herein.

Further, in the exemplary embodiment, a single heat exchanger 124 (broadly a "control system") is used to control the temperature of the fluid, but in other embodiments, multiple heat exchangers may be used instead. For example, a single heat exchanger may be used to control the temperature of the fluid in contact with the rotatable lace 116 of all the bearings 114 and the other heat exchanger may be used to control the temperature of the fluid in contact with the stationary race 118 Lt; / RTI > The heat exchanger 124 is of any suitable type and is operable to cool and / or heat the fluid. By controlling the temperature of the fluid, the heat exchanger is operable to control the temperature of the bearings 114 in thermal communication with the fluid.

A displacement sensor 130 (broadly, a "sensor") is disposed adjacent to the rotatable race 116 to measure the movement and / or axial displacement of the rotatable race 116. Similarly, another displacement sensor 132 may be positioned adjacent to the stationary race 118 to measure the displacement of the stationary race 118. In other embodiments, one of these sensors 130, 132 may be omitted. In the exemplary embodiment, these sensors 130, 132 measure the axial displacement of each race 116,118 and are non-contact sensors. In other embodiments, these sensors 130 and 132 may be configured and / or positioned differently to measure different types of movement of the bearings 114. [ The sensors 130 and 132 are communicatively coupled to the processor 140 (discussed in more detail below) by any suitable communication system (e.g., a wireless and / or wired network).

Although only one of each sensor 130,132 is shown in the figures for clarity, each race of each bearing 114 in thermal communication with the fluid has such sensors in the exemplary embodiment. In other embodiments, the sensors 130, 132 may be located adjacent to different bearings 114 or portions thereof to measure displacement of each bearing or a portion thereof.

Temperature sensors are placed in thermal communication with the fluid to measure the temperature of the fluid. In an exemplary embodiment, the temperature sensor 134 is disposed adjacent to the rotatable race 116 and the temperature sensor 136 is disposed adjacent to the stationary race 118. Thus, the temperature sensors 134, 136 are located adjacent to each race in thermal communication with the fluid, whereby the fluid is also in thermal communication with each race. Because the fluid in these positions is in thermal communication with each race 116,118, the temperature of the fluid represents the temperature of the lace. In an exemplary embodiment, it is assumed that the temperature of the fluid adjacent to each race 116,118 is substantially the same as the temperature of this race. In other embodiments, this may not be the case and the temperature of the fluid adjacent to the lace 116, 118 may be different from the temperature of the race. The temperature sensors 134 and 136 are also communicatively coupled to the processor 140 (discussed in more detail below) by any suitable communication system (e.g., a wireless and / or wired network).

A processor, schematically depicted in Figures 2 and 3 and generally designated by the reference numeral 140, is communicatively coupled to the temperature sensors 134, 136, displacement sensors 130, 132, and heat exchanger 124. As discussed generally below, the processor 140 is configured to receive input from a user identifying a desired wafer nanopolar profile or shape of the sliced wafers from the ingot. Based on these inputs and the measured temperature of the fluid, the processor 140 sends instructions to the heat exchanger 124 to control (i.e., adjust, change, or change) the temperature of the fluid. As such, temperature regulation of the fluid may control the temperature of a portion of the bearings 114 in contact with the fluid, thereby controlling the temperature of other portions of the bearing. This change in temperature of the bearing 114 changes the displacement of the bearings and the displacement of the wire guides 106 and the wires 104. Controlling the displacement of the wire guides 106 and wires 104 controls the shape of the surfaces of the wafers so that the shape control of the surfaces of the wafers controls the nanotopology of the surfaces.

The operation of the processor 140 and the system 100 will now be described in more detail. An input device 160 (shown schematically in FIGS. 2 and 3) is communicatively coupled to the processor 140 and may be used to receive input identifying the desired wafer nanopolar or wafer shape from the user. In other embodiments, the processor 140 may receive such input from another computer system communicatively coupled to the processor.

Once this input is received by the processor 140, the processor retrieves the recipe associated with the input from the memory 150. The memory is described in more detail below. The recipe specifies a temperature set point (i.e., the desired temperature) of the temperature-controlled fluid and / or bearings 114 associated with the recipe. The recipe may also include a displacement measurement of the bearings in addition to or in place of the temperature set points of the bearings and / or the fluid. According to the temperature and / or displacement measurements contained in the recipe during cutting the ingot 102 by the wire saw 103, wafers having properties that are generally the same or similar to the input can be mass produced. This recipe may be referred to interchangeably as "temperature profile "," displacement profile "and / or" temperature displacement profile ".

Recipes can be created according to a variety of different methods. The specific temperatures and / or displacements of each recipe may be determined empirically based on the material properties of the bearings 114 (i.e., the thermal expansion coefficient (s) of the materials of the bearing) or experimentally (i.e., Lt; / RTI > In one embodiment, recipes are created experimentally by measuring the displacement of the bearings 114 and / or the temperature of the fluid and the bearing during ingot 102 slicing and storing the measurements in memory 150. The surface of at least one of the wafers is then measured and the shape of the wafer and / or properties of the nanotoporage are stored in memory 150. Along with the temperature measurements and / or displacement measurements, these characteristics of the wafer form the recipe. As will be described below, this process may also be used to periodically update recipes.

As noted above, in an exemplary embodiment, the temperature of the bearings 114 is generally equivalent to the temperature of the temperature control fluid in thermal communication with these bearings. Using these recipes by the system, recipes are associated with these inputs so that sliced wafers by the saw 103 can have the desired topology and / or shape of the input. These recipes are stored in the memory 150 communicatively coupled to the processor 140. The memory 150 is any suitable form of computer readable medium including storage devices of a type (e.g., hard disk drive, flash memory, optical drive, etc.).

These temperatures of the fluid can change the position of the bearings 114 so that the sliced wafers by the saw 103 can have the desired topology and / or shape. In an exemplary embodiment, processor 140 retrieves temperature set points from memory 150.

In operation, the saw 103 begins to slice the ingot 102 and the processor 140 sends instructions to the heat exchanger 124 to adjust the temperature of the fluid based on the measured temperature and set point of the fluid send. Once the temperature of the fluid is equal to the temperature setpoint, the processor 140 sends instructions to the heat exchanger 124 to stop the temperature control of the fluid. The processor 140 may continue to monitor the temperature measurements received from the temperature sensors 134, The processor 140 sends instructions to the heat exchanger 124 to re-adjust the temperature of the fluid as the temperature of the fluid deviates from the temperature set point by an amount greater than the variation (e.g., about +/- 0.1 degrees Celsius).

In other embodiments, rather than adjusting the temperature of the fluid to control the temperature of the bearings, the flow rate of the fluid is regulated to regulate the temperature of the bearings. The fluid temperature is not measured and instead the temperature of the bearings 114 is measured by the temperature sensors 134,136. The temperature sensors 134 and 136 are positioned so that they can measure the temperature of the bearings 114 (i.e., these sensors contact a portion of the bearings). In these embodiments, the recipe includes a temperature profile that describes the temperature set points of the bearings rather than the temperature set point of the fluid. The recipe may be created and updated in accordance with methods similar or similar to those described herein.

In these embodiments, a valve 170 (broadly, a "control system") is provided to control the temperature of the bearings 114 by controlling (adjusting, changing or changing) the flow rate of the fluid. Valve 170 is in fluid communication with inlets 120, 126 and / or outlets 122, 128 through pipes, hoses or other suitable structures. A plurality of valves 170 may be used in some embodiments to control the flow rate of the fluid. Valve 170 may also be communicatively coupled to processor 140 and actuated by an actuator or other suitable device. According to some embodiments, the valve 170 is a proportional control valve, while in other embodiments the valve is any suitable valve (e. G., A ball valve or a gate valve). In other embodiments, a variable flow rate pump may be used in place of or in conjunction with a valve to control the flow rate of the fluid.

If the flow rate of the fluid is increased by the valve 170 (e.g., by opening more of the valve), the fluid may cause more heat from the bearing 114 to be transmitted to the outside. Thereby, the fluid can cool the bearing 114 and lower the temperature. The opposite effect occurs when the flow rate of the fluid is reduced by the valve 170 (e.g., by closing more of the valve). That is, when the flow of the fluid is reduced, the fluid can not allow more heat from the bearing 114 to be transmitted to the outside. The temperature of the bearing 114, which depends on the flow rate of the fluid, can thus be maintained or increased without increasing rapidly.

Such a change in the temperature of the bearing 114 resulting from a change in the flow rate of the fluid changes the displacement of the bearing and changes the displacement of the wire guides 106 and the wires 104. Controlling the displacements of the guides 106 and the wires 104 controls the shape of the surfaces of the wafers, thereby controlling the nanotopology of the surfaces.

Thus, in this embodiment no heat exchanger is used to control the temperature of the fluid. The fluid may be cooled to a relatively constant temperature (e.g., from about 5 캜 to about 10 캜) obtained from a reservoir or other source prior to circulation in contact with the bearings 114, Lt; / RTI > After contact with the bearing, the fluid returns to the reservoir.

In other embodiments, the temperature and displacement of the bearing 114 are controlled by adjusting the flow rate of the fluid with the temperature of the fluid being adjusted. Temperature sensors 134, 136 may be used to measure the temperature of the fluid and / or the bearing 114. A valve and / or a variable flow rate pump as described above may be used to control the flow rate of the fluid to control the temperature of the bearing 114. The heat exchanger 124 as described above can be used to control the temperature of the fluid. In these embodiments, the recipes include a temperature set point of the bearing in addition to the temperature set point of the fluid.

In accordance with some embodiments, the temperature set points are also determined based on the measured displacement of the stationary race 118 of the bearing 114 and / or of the rotatable race 116. For example, if the measured displacement of the bearing 114 is within the range of displacements specified by the recipe, the temperature set point is adjusted such that the temperature of the fluid in thermal communication with the bearing and / or the flow rate of the fluid is not changed . As such, the measured displacement of the bearing 114 serves as feedback to the processor to adjust the temperature set point.

In some embodiments, the recipes are updated by measuring the surfaces of the sliced wafers from the ingot after the slicing operation. For example, the surfaces of the wafers are measured and compared with the desired wafer shape and / or nanoporous profile input by the user. If the measurements on the surface differ from those entered by the user, the recipe may be updated. Such an update includes adjusting the temperature set point of the fluid contained in the recipe and / or the flow rate of the fluid. This update also includes the adjustment of the desired displacements of the portions of the bearing 114.

In other embodiments, the displacements of the bearings 114 are measured by the displacement sensors 130, 132 at the intervals set during the 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 the temperature set points of the bearings necessary to eliminate or eliminate the negative effects of these displacements on the wafers 114 by reducing or eliminating the displacements of the bearings 114.

The processor 140 then sends instructions to the heat exchanger 124 to control the temperature of the fluid based at least in part on the measured displacement of the bearings 114. [ In embodiments using valve 170, the processor 140 also sends instructions to the valve to control the flow rate of the fluid. The instructions to the valve 170 are also based at least in part on the measured displacement of the bearing 114. The operation of controlling both the heat exchanger 124 and the valve 170 controls the temperature of the bearings 114, thereby controlling the displacement of the bearings. In addition, the instructions generated by processor 140 may also be based, at least in part, on one or more of the recipes stored in memory 150.

In one example, the processor 140 may determine a temperature set point based on a measured displacement of the bearings 114 or portions thereof. The processor then sends instructions to the heat exchanger 124 to cool the fluid based on the measured displacements of the bearings 114 or portions thereof. The fluid temperature reduction lowers the temperature of the bearings 114, which removes or reduces the displacement of the bearings. Also, temperature sensors 134 and 136 may be used to measure the temperature of fluid and / or bearing 114 and transmit these temperature measurements to processor 140. These temperature measurements serve as feedback to the processor 140.

In still other embodiments, during slicing of the ingot 102, only the temperature of the fluid is controlled and the displacement of the bearing 114 is not measured. In these embodiments, the heat exchanger 124 controls the temperature of the fluid to control the temperature of the bearings 114 in accordance with the temperature set point. This temperature set point can be retrieved from the recipe as described above. Alternatively, the temperature set point may be received as input to the system 100 from a user or other computer system. The system 100 may in some embodiments use the respective sensors 134, 136 to measure the temperature of the fluid and to use this measurement as feedback to control the heat exchanger 124.

In still other embodiments, during ingot 102 slicing, only the flow rate of the fluid is controlled and the displacement of the bearings 114 is not measured. In these embodiments, the valve 170 controls the flow rate of the fluid to control the temperature of the bearings 114 in accordance with the temperature set point. This temperature set point can be retrieved from the recipe as described above. Alternatively, the temperature set point may be received as input to the system 100 from a user or other computer system. The system 100 may use the respective sensors 134 and 136 in some embodiments to measure the temperature of the bearings 114 and use this measurement as feedback to control the valve 170. [

The systems and methods described herein control the nanotopology and shape of the wafers cut in the wire saw machine 103. In conventional systems it has been determined that sometimes bearings 114 or portions thereof are subjected to displacement or movement during ingot 102 slicing. Graph 1 shows the experimental data illustrating these varying displacements of the bearings 114. As shown in the graph of Fig. 4, the displacement of the stationary race 118 can be kept relatively constant during ingot 102 slicing by wire saw 103. However, the displacement of the rotatable race 116 is obviously obvious. Thus, in an exemplary embodiment, the system 100 is associated with controlling the displacement of the rotatable race 116. In other embodiments, the displacement of the stationary race 118 may be controlled with or instead of the displacement of the rotatable race 116.

This displacement of the bearing 114 causes displacement of the wire guides 106 and the wires 104 of the wire saw 103. The displacement of the wire guides 106 and wires 104 then results in the shape of the wafers sliced from the ingot 102 and / or the defects in the nanoporous. Entry traces and entry traces are the type of such defects. The displacement of the bearing 114 is believed to be caused by the temperature change of the bearing and thereby the temperature of the fluid in thermal communication with the bearing. The graph of FIG. 5 shows experimental data illustrating the relationship between the temperature of the bearings and their displacement. The graph of Fig. 6 shows experimental data illustrating the correlation between the displacement of the bearings and the wafer geometry. In particular, the uppermost data set represents the mean displacement value of the bearing, while the intermediate data set (including the series of data for the six wafers) represents warp measurements taken at the wafers . The lowest data (including a series of data for the same six wafers) represents the WI measurements of the wafers. WI is the mathematical transformation of the warp measures, which are predictions of the wafer's nanotopology after the wafer is polished. "FB" and "MB" specify the positions of the wafers relative to wire saw 103.

By controlling the temperature of the fluid in contact with the bearings 114, the systems and methods described herein can control the temperature of the bearings. Also, controlling the flow of the fluid may be used instead of or in addition to controlling the fluid temperature to control the temperature of the bearings. Controlling the temperature of the bearings 114 can control the displacement of the bearings. Thus, the displacement of the bearings 114 can be minimized or eliminated by controlling the temperature of the bearings. By doing so, the displacement of the wire guides 106 and the wires 104 can also be minimized or eliminated. This can eliminate or reduce the shape of the wafers and / or defects (e.g., entry marks or entry marks) in the nanotoporage of the wafers. This decrease in defects increases the yield of the wafer fabrication process. In addition, the time of subsequent processing operations (e.g., double-sided polishing) can be reduced or eliminated, thereby reducing wafer manufacturing cost and time.

The systems and methods also allow the user to control the shape and / or nanotopology of the wafers in addition to, or instead of, reducing or eliminating other defects (e. G., Entry traces or entry traces) . Thus, the user can enter the desired shape and / or nanoporous of the sliced wafers from the ingot 102. Users can desire wafers with different shapes and / or nanopolarities for various reasons.

For example, wafers subjected to an epi-deposition process may be bowed or warped to some extent by this process. In these cases, the shape of the wafers can be controlled by the system 100 described above during ingot 102 slicing so that the wafers have warp or bow opposite to bow or bow resulting from the epi-deposition process. have. For example, if the later epitaxial deposition process tends to bow the wafer in the convex direction, the shape of the wafers can be controlled by the present system to have a concave shape after the wafers are sliced. Thus, once the wafers are later subjected to an epi-deposition process, the concave shape of the wafers offset the tendency of this process to warp the wafer into a convex shape. As such, the wafers will have a substantially planar shape after the epi-deposition process is completed.

In introducing elements of the present disclosure or elements of the embodiments of the present disclosure, the plural, singular, and the phrases "above" of the elements are intended to mean that there are one or more of the elements. The terms "comprises" and "having" do not exclude the presence of additional elements other than the listed elements.

It is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense, as various changes may be made therein, without departing from the scope of the present disclosure.

Claims

A system for controlling a surface profile of sliced wafers from an ingot in a wire saw,
Wherein the wire saw includes a wire guide that supports wires, the wire guide rotates on a bearing, the wire saw includes a fluid in thermal communication with the bearing,
The system comprises:
A memory for storing temperature profiles, each temperature profile associated with a surface profile and defining a temperature set point for at least one of said fluid and said bearing;
A control system for controlling the temperature of the bearing;
A temperature sensor for measuring a temperature of at least one of the fluid and the bearing; And
And a processor communicatively coupled to the memory, the control system, and the temperature sensor,
Wherein the processor is configured to receive an input identifying a desired surface profile and retrieve associated temperature set points from the memory,
Wherein the processor is configured to transmit to the control system instructions to control the temperature of the bearing based at least in part on the temperature set point and the measured temperature of at least one of the fluid and the bearing, system.

The method according to claim 1,
And a sensor coupled to the processor and arranged to measure displacement of the bearing of the wire guide.

3. The method of claim 2,
Wherein the sensor is a first sensor and is arranged to measure a displacement of a rotating race of the bearing.

The method of claim 3,
Further comprising a second sensor arranged to measure a displacement of a stationary race of the bearing.

The method according to claim 1,
Further comprising an input device for receiving an input identifying the desired surface profile,
Wherein the input device is communicatively coupled to the processor.

The method according to claim 1,
Wherein the control system comprises at least one of a heat exchanger for controlling the temperature of the fluid and a valve for controlling the flow rate of the fluid.

A system for controlling the surface profile of wafers cut from an ingot by wire sawing,
A wafer measuring sensor for measuring a surface of the wafer previously cut by the wire saw;
A sensor disposed to measure a displacement of a bearing of a wire guide supporting the wires in the wire saw; And
A processor for determining a temperature set point,
Wherein the processor is configured to determine the temperature set point based at least in part on one of a measured displacement of the bearing and a measured surface of the previously cut wafer,
Wherein the processor is communicatively coupled to the wafer measurement sensor and the sensor.

8. The method of claim 7,
Wherein the sensor is arranged to measure displacement of at least one of a rotatable race of the bearing and a stationary race of the bearing.

8. The method of claim 7,
Wherein the sensor is a first sensor for measuring a displacement of the rotational type race of the bearing,
Further comprising a second sensor for measuring a displacement of the stationary race of the bearing.

8. The method of claim 7,
Further comprising a heat exchanger for controlling the temperature of the fluid,
Wherein the heat exchanger is communicatively coupled to the processor.

8. The method of claim 7,
Further comprising a memory for storing at least one of the measurements of the surface of the previously cut wafer and the temperature set point.

8. The method of claim 7,
Further comprising a temperature sensor for measuring the temperature of the fluid,
Wherein the temperature sensor is communicatively coupled to the processor.

A system for controlling a surface profile of wafers sliced from an ingot in a wire saw,
The wire saw comprising a wire guide for supporting wires, the wire guide rotating on a bearing, the wire saw comprising a fluid in thermal communication with the bearing,
The system comprises:
A memory for storing temperature profiles, each temperature profile being associated with a surface profile and defining a temperature set point for said bearing;
A valve for controlling a flow rate of the fluid;
A temperature sensor for measuring the temperature of the bearing; And
And a processor communicatively coupled to the memory, the valve, and the temperature sensor,
Wherein the processor is configured to receive an input identifying a desired surface profile and retrieve associated temperature set points from the memory,
Wherein the processor is configured to transmit instructions to the valve to control a flow rate of the fluid based at least in part on the temperature set point of the bearing and the measured temperature.

14. The method of claim 13,
And a sensor coupled to the processor and arranged to measure displacement of the bearing of the wire guide.

15. The method of claim 14,
Wherein the sensor is a first sensor and is arranged to measure a displacement of the rotational race of the bearing.

16. The method of claim 15,
Further comprising a second sensor arranged to measure a displacement of the stationary race of the bearing.

14. The method of claim 13,
Further comprising an actuator for controlling said valve,
And wherein the actuator is communicatively coupled to the processor.

14. The method of claim 13,
Further comprising a fluid temperature sensor for measuring the temperature of the fluid,
Wherein the fluid temperature sensor is communicatively coupled to the processor.

19. The method of claim 18,
Further comprising a heat exchanger for controlling the temperature of the fluid.

20. The method of claim 19,
Each temperature profile further defines a temperature set point for the fluid,
Wherein the processor is configured to transmit instructions to the heat exchanger to control the temperature of the fluid based at least in part on the temperature set point of the fluid and the measured temperature.

1. A method of slicing a semiconductor or solar cell ingot into wafers using wire saws,
The wire saw comprising a wire guide for supporting wires, the wire guide rotating on a bearing, the wire saw comprising a fluid in thermal communication with the bearing,
The method comprises:
Receiving an input from a user including a desired wafer surface profile;
Selecting a temperature and displacement profile based on the input;
Initiating a slicing operation;
Measuring a displacement of the bearing;
Measuring at least one of a temperature of the bearing and a temperature of the fluid;
Determining a temperature set point based at least in part on one of the measured displacement of the bearing, the selected temperature and displacement profile, and the measured temperature of at least one of the fluid and the bearing; And
Controlling the temperature of at least one of the fluid and the bearing based on the temperature set point
/ RTI >

22. The method of claim 21,
Wherein a displacement of a portion of the bearing of the wire guide is measured.

23. The method of claim 22,
Wherein a portion of the bearing is a rotatable race.

24. The method of claim 23,
Further comprising measuring displacements of the stationary race of the bearing.

25. The method of claim 24,
Wherein the temperature set point is determined based at least in part on the measured displacement of the stationary race of the bearing.

22. The method of claim 21,
Wherein the temperature of the fluid is controlled by a heat exchanger.

22. The method of claim 21,
Wherein the temperature of the bearing is controlled by at least one of a heat exchanger for controlling the temperature of the fluid and a valve for controlling the flow rate of the fluid.

A method of slicing an ingot into wafers using a wire saw,
The wire saw comprising a wire guide for supporting wires, the wire guide rotating on a bearing, the wire saw comprising a fluid in thermal communication with the bearing,
The method comprises:
Receiving an input from a user including a desired surface profile;
Selecting a recipe based on the desired surface profile, the recipe comprising a temperature profile defining a temperature set point for the fluid;
Controlling the temperature of the fluid based on the selected recipe, wherein controlling the temperature of the fluid controls the temperature of the bearing; And
Starting the slicing operation
/ RTI >

29. The method of claim 28,
Further comprising measuring the temperature of the fluid,
Wherein the temperature of the fluid is controlled based at least in part on the measured temperature of the fluid.

29. The method of claim 28,
A displacement of the bearing of the wire guide is measured,
Wherein the temperature set point is determined based at least in part on the measured displacement of the bearing.

29. The method of claim 28,
Wherein the temperature of the fluid is controlled by a heat exchanger.

29. The method of claim 28,
Wherein the temperature set point is determined by the processor.

29. The method of claim 28,
Wherein the steps of the method are repeated at predetermined intervals during slicing the ingot into wafers using the wire saw.

A method of slicing an ingot into wafers using a wire saw,
Wherein the wire saw comprises a wire guide for supporting wires, the wire guide rotating on a bearing, the wire saw comprising a fluid in thermal communication with the bearing and a valve for controlling a flow rate of the fluid,
The method comprises:
Receiving an input from a user including a desired surface profile;
Selecting a recipe based on the input, the recipe comprising at least one of a temperature profile and a displacement profile for the bearing;
Controlling a flow rate of the fluid based on the selected recipe, the step of controlling the flow rate of the fluid controlling a temperature of the bearing; And
Starting the slicing operation
/ RTI >

35. The method of claim 34,
Further comprising determining a temperature set point based at least in part on the selected recipe,
Wherein the flow rate of the fluid is controlled based at least in part on the temperature set point.

36. The method of claim 35,
Wherein the temperature set point is determined by the processor.

35. The method of claim 34,
Wherein the steps of the method are repeated at intervals set during slicing the ingot into wafers using the wire saw.

35. The method of claim 34,
Further comprising measuring the temperature of the fluid,
Wherein at least one of the flow rate and the temperature of the fluid is controlled based at least in part on the measured temperature of the fluid.

39. The method of claim 38,
Wherein the temperature of the fluid is controlled by a heat exchanger.

35. The method of claim 34,
Further comprising measuring a displacement of the bearing,
Wherein the flow rate of the fluid is controlled based at least in part on the measured displacement of the bearing.

A method of controlling a surface profile of sliced wafers from an ingot using a wire saw,
(a) measuring a surface of a wafer previously cut by the wire saw;
(b) measuring displacements of the bearings of the wire guides supporting the wires in the wire saw;
(c) determining a temperature set point of the bearing based in part on at least one of the measured displacement of the bearing and the measured surface of the previously cut wafer; And
(d) controlling the temperature of the fluid circulating in contact with the bearing based on the temperature set point, the controlling temperature controlling the temperature of the bearing, Controlling the surface profile of the sliced wafers from the ingot by sawing,
Wherein the wafer surface profile control method comprises:

42. The method of claim 41,
Wherein the steps (b) to (d) are repeated at intervals set during slicing the ingot into wafers.

42. The method of claim 41,
Wherein a displacement of the rotary race of the bearing of the wire guide is measured.

44. The method of claim 43,
Further comprising measuring a displacement of the stationary race of the bearing.

45. The method of claim 44,
Wherein the temperature set point is determined based at least in part on the measured displacement of the stationary race of the bearing.

42. The method of claim 41,
Further comprising measuring the temperature of the fluid.

47. The method of claim 46,
Wherein controlling the temperature of the fluid is based at least in part on a measured temperature of the fluid.

CLAIMS 1. A method of controlling displacement of a bearing in a wire saw for slicing a semiconductor or solar charge ingot into wafers,
The wire saw comprising a wire guide for supporting wires, the wire guide rotating on the bearing and the wire saw comprising a fluid in thermal communication with the bearing,
The method comprises:
Measuring a displacement of the bearing;
Determining a temperature set point of the bearing based at least in part on the measured displacement of the bearing; And
Controlling at least one of a flow rate of the fluid based on the temperature and the temperature set point based on the temperature set point, wherein controlling at least one of a temperature and a flow rate of the fluid comprises: Displacement control -
Wherein the bearing displacement control method comprises:

49. The method of claim 48,
Wherein a displacement of a portion of the bearing is measured.

50. The method of claim 49,
Wherein the portion of the bearing is a rotatable race.

51. The method of claim 50,
Further comprising the step of measuring a displacement of the stationary race of the bearing.

52. The method of claim 51,
Wherein the temperature set point is determined based at least in part on the measured displacement of the stationary race of the bearing.

49. The method of claim 48,
Further comprising measuring the temperature of the fluid,
Wherein controlling the temperature of the fluid is based at least in part on the measured temperature of the fluid.

49. The method of claim 48,
Wherein the temperature set point is determined by the processor.

49. The method of claim 48,
Further comprising measuring the temperature of the bearing,
Wherein controlling the flow rate of the fluid is based at least in part on the measured temperature of the bearing.

49. The method of claim 48,
Wherein the flow rate of the fluid is controlled by a valve.

49. The method of claim 48,
Wherein the temperature of the fluid is controlled by a heat exchanger.

CLAIMS 1. A method of controlling displacement of a bearing in a wire saw for slicing an ingot into wafers,
Measuring a displacement of the bearing of the wire guide supporting the wires in the wire saw;
Determining a temperature set point based at least in part on the measured displacement of the bearing; And
Controlling the temperature of the fluid circulating in contact with the bearing based on the temperature set point, wherein controlling the temperature of the fluid controls displacement of the bearing,
Wherein the bearing displacement control method comprises:

59. The method of claim 58,
Wherein the steps are repeated at intervals set during slicing of the ingot into wafers using the wire saw.

59. The method of claim 58,
Further comprising measuring the temperature of the fluid,
Wherein controlling the temperature of the fluid is based at least in part on the measured temperature of the fluid.

A system for controlling the surface profile of wafers cut from an ingot by wire sawing,
A sensor disposed to measure a displacement of a bearing of a wire guide supporting the wires in the wire saw; And
A processor communicatively coupled to the sensor and configured to determine a temperature setpoint for the bearing,
Wherein the processor is configured to determine the temperature set point based at least in part on a measured displacement of the bearing,
Wherein the use of the temperature set point in controlling the temperature of the bearing controls the surface profile of the wafers cut from the ingot by the wire saw.

62. The method of claim 61,
Wherein the surface profile of the wafers comprises at least one of a nano topology of the wafer and a shape of a surface of the wafer.

62. The method of claim 61,
Wherein the sensor is arranged to measure a displacement of the rotational race of the bearing.

62. The method of claim 61,
Wherein the sensor is arranged to measure displacements of the stationary race of the bearing.

64. The method of claim 63,
Wherein the sensor is a first sensor,
Further comprising a second sensor communicatively coupled to the processor for measuring displacement of the stationary race of the bearing.

62. The method of claim 61,
Wherein the processor is configured to provide instructions to the heat exchanger to control the temperature of fluid circulating in contact with the bearing,
Wherein controlling the temperature of the fluid is to control displacement of the bearing,
Wherein controlling the displacement of the bearing controls the surface profile of the wafers cut from the ingot by the wire saw.

67. The method of claim 66,
Further comprising a temperature sensor for measuring the temperature of the fluid,
Wherein the temperature sensor is communicatively coupled to the processor.

68. The method of claim 67,
Wherein the processor is configured to provide instructions to the heat exchanger to control the temperature of the fluid based at least in part on the measured temperature of the fluid.

62. The method of claim 61,
Further comprising a temperature sensor for measuring the temperature of the bearing,
Wherein the temperature sensor is communicatively coupled to the processor.

70. The method of claim 69,
Wherein the processor is configured to determine the temperature set point based at least in part on a measured temperature of the bearing,
Wherein the processor is configured to provide instructions to the valve to control a flow rate of the fluid based at least in part on the temperature set point,
Wherein controlling the flow rate of the fluid is to control displacement of the bearing,
Wherein controlling the displacement of the bearing controls the surface profile of the wafers cut from the ingot by the wire saw.

A system for controlling nanotopology of sliced wafers in a wire saw for slicing a semiconductor or solar cell ingot into wafers,
The wire saw comprising a wire guide for supporting wires, the wire guide rotating on a bearing and the wire saw comprising a fluid in thermal communication with the bearing,
The system comprises:
A sensor disposed to measure a displacement of the bearing of the wire guide;
A processor communicatively coupled to the sensor and configured to determine a temperature set point to be used in controlling the temperature of the fluid, the processor configured to determine the temperature set point based at least in part on the measured displacement of the bearing Wherein controlling the temperature of the fluid is to control displacement of the bearing and controlling displacement of the bearing controls nanotopology of the wafers cut from the ingot by the wire saw; And
A memory configured to be communicatively coupled to the processor and configured to store the temperature set point;
And a wafer nano topology control system.

72. The method of claim 71,
Wherein the sensor is arranged to measure a displacement of the rotational race of the bearing.

72. The method of claim 71,
Wherein the sensor is arranged to measure displacements of the stationary race of the bearing.

72. The method of claim 71,
Wherein the sensor is a first sensor for measuring a displacement of the rotational type race of the bearing,
Further comprising a second sensor for measuring a displacement of the stationary race of the bearing.

72. The method of claim 71,
Further comprising a heat exchanger for controlling the temperature of the fluid,
The heat exchanger being communicatively coupled to the processor,
Wherein controlling the temperature of the fluid controls displacement of the bearing.

72. The method of claim 71,
And a temperature sensor for measuring the temperature of the fluid,
Wherein the temperature sensor is communicatively coupled to the processor.

A system for controlling the surface profile of sliced wafers in a wire saw for slicing a semiconductor or solar cell ingot into wafers,
The wire saw comprising a wire guide for supporting wires, the wire guide rotating on a bearing and the wire saw comprising a fluid in thermal communication with the bearing,
The system comprises:
A sensor disposed to measure a displacement of the bearing of the wire guide;
A processor communicatively coupled to the sensor and configured to determine a temperature set point used in controlling the flow rate of the fluid, the processor determining the temperature set point based at least in part on the measured displacement of the bearing Wherein controlling the flow rate of the fluid is to control displacement of the bearing and wherein controlling the displacement of the bearing controls the surface profile of the wafers cut from the ingot by the wire saw; And
A memory configured to be communicatively coupled to the processor and configured to store the temperature set point;
The wafer surface profile control system.

78. The method of claim 77,
Further comprising a valve for controlling a flow rate of the fluid,
Wherein the valve is communicatively coupled to the processor.

78. The method of claim 77,
Wherein the processor is configured to determine the temperature set point to be used in controlling the temperature of the fluid.

80. The method of claim 79,
Further comprising a heat exchanger for controlling the temperature of the fluid,
Wherein the heat exchanger is communicatively coupled to the processor.