Algorithm for accurately converting a wide range of photoelectric signals into electric current

Abstract

Embodiments disclosed herein include a method for calibrating a tool for converting a photonic signal into an electrical signal. In one embodiment, the method includes connecting a calibration module to a calibrated current source, finding transfer functions for a plurality of modes by the calibration module, and storing the transfer functions in a look-up table.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Patent Application No. 17 / 862,278, filed on 11 July 2022, which is incorporated herein by reference in its entirety.

[0002] The embodiments relate to the field of semiconductor manufacturing, and more specifically to processes and apparatus for calibrating pyrometers and emitters. [Background technology]

[0003] Temperature control is a critical parameter for many processing operations in the semiconductor industry. For example, temperature control across the surface of a substrate (e.g., a silicon wafer) is important for achieving process uniformity in applications such as thermal oxidation and thermal treatment. Due to the complexity of semiconductor processing tools, temperature readings for such processes are generally implemented by non-contact temperature measurement systems. Non-contact measurement tools may include pyrometers, emitters, etc. Generally, temperature measurement tools include a photodiode that receives an optical signal from the surface of the substrate being measured. For example, an infrared signal may be received by the photodiode.

[0004] Generally, photocurrents are converted into digital (electrical) signals. In semiconductor processing, photocurrents have a wide range. For example, a photocurrent can be of multiple magnitudes (e.g., 10 magnitudes). In a particular case, the photocurrent is 10 -14 From 10 amperes (A) -4 It can span between A and B. While analog-to-digital converters (ADCs) used with such systems may have high resolution, the ADC is limited in sensitivity across its entire dynamic range. [Overview of the project]

[0005] Embodiments disclosed herein include a method for calibrating a tool for converting photonic signals into electrical signals. In one embodiment, the method includes connecting a calibration module to a calibrated current source, using the calibration module to find transfer functions for multiple modes, and storing the transfer functions in a lookup table.

[0006] In one embodiment, a tool is provided for converting a photonic signal into an electrical signal. In one embodiment, the tool comprises a photodiode, a signal scaling module, an ADC, a selector module, and a current calculation module.

[0007] In one embodiment, a method for converting a photonic signal to an electrical signal includes receiving an optical signal with an ADC, selecting a mode based on the location of the optical signal within the dynamic range of the ADC, setting an integral time and range for the mode, and calculating a current based on a transfer function for the mode. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram of a pyrometer that measures the temperature of a thermal body using a non-contact solution according to one embodiment. [Figure 2A] This is a diagram of various modules in a pyrometer, including an integrated calibration module for a pair of photodiodes, according to one embodiment. [Figure 2B] This is a diagram of various modules in a pyrometer, including an integrated calibration module for a single photodiode, according to one embodiment. [Figure 3] This is a process flow diagram of a process for calibrating a high-temperature meter according to one embodiment. [Figure 4] This is a process flow diagram of a process for using a calibrated pyrometer according to one embodiment. [Figure 5] This is a block diagram of a pyrometer including an integrated calibration module according to one embodiment. [Figure 6] This is a process flow diagram for assembling and calibrating a pyrometer according to one embodiment. [Figure 7] This is a cross-sectional view of a semiconductor processing tool including one or more thermometers according to one embodiment. [Figure 8] This is a block diagram of an exemplary computer system that may be used with a processing tool according to one embodiment. [Modes for carrying out the invention]

[0009] The systems described herein include processes and apparatus for calibrating pyrometers and emitters. Numerous specific details are provided in the following description to provide a complete understanding of the embodiments. It will be apparent to those skilled in the art that embodiments can be practiced without these specific details. In other cases, well-known aspects are not described in detail so as not to unnecessarily obscure the embodiments. Furthermore, it should be understood that the various embodiments shown in the accompanying drawings are illustrative and not necessarily drawn to a specific scale.

[0010] As described above, non-contact temperature measurement solutions are used to provide improved process uniformity across the substrate surface. Non-contact temperature measurement solutions may include emitters and pyrometers. Any reference used herein to either an emitter or a pyrometer may be considered to include both an emitter and a pyrometer. That is, the embodiments described herein are applicable to both emitters and pyrometers.

[0011] Generally, non-contact temperature measurement solutions include an analog-to-digital converter (ADC). While ADCs can have high resolution, they lack sensitivity across the entire dynamic range. Therefore, embodiments disclosed herein include pyrometer and / or emitter solutions that include hardware, firmware, and / or software enabling the implementation of an internal calibration process. For example, the dynamic range of an ADC may be utilized in multiple modes. Each mode may include an integration time and a range. The integration time may be an integration time set for the ADC to record a value, and the range may be a value used by a signal scaling module. In one embodiment, each mode may be associated with a transfer function including two or more coefficients (e.g., coefficients k and b). When a particular mode is selected, the associated transfer function coefficients are used to calculate a calibrated current. For example, coefficient k may be multiplied by the ADC value, and coefficient b may be an offset. In some embodiments, a dark current value may also be used to measure temperature more accurately.

[0012] Referring next to Figure 1, a diagram of a processing system 100 according to one embodiment is shown. The processing system 100 may include a pyrometer 120 and a thermal body 121. The pyrometer 120 uses a non-contact measurement process to measure the temperature of the thermal body 121. For example, thermal energy 122 (e.g., infrared electromagnetic radiation) may be emitted by the thermal body 121 and propagated toward the pyrometer 120. The pyrometer 120 may include one or more photodiodes to convert the photothermal energy 122 into a digital signal that can be used to calculate the temperature of the thermal body 121. As will be described in more detail below, the pyrometer 120 may include an integrated calibration module to properly calibrate the pyrometer 120.

[0013] In one embodiment, the thermal body 121 can include any number of components used in a semiconductor manufacturing process. For example, the thermal body 121 can be a semiconductor substrate such as a silicon wafer, or any other semiconductor wafer. In other embodiments, the thermal body 121 can be a glass substrate, a ceramic substrate, etc. The temperature of the components of the semiconductor processing tool can also be measured by the pyrometer described herein. For example, the thermal body 121 can include a chamber lid, a chucking surface, etc. More generally, the thermal body 121 can be any object whose temperature is desired to be measured. That is, the pyrometer 120 disclosed herein is not limited to a semiconductor processing environment.

[0014] In one embodiment, the pyrometer 120 can be integrated in a semiconductor processing tool. For example, a rapid thermal processing (RTP) chamber, such as a thermal oxidation chamber, can utilize one or more pyrometers 120. However, it should be understood that any type of semiconductor processing tool can benefit from the non-contact temperature measurement provided by the pyrometer 120 described herein. An example of a specific processing chamber that utilizes one or more pyrometers 120 is shown in more detail below with respect to FIG. 7.

[0015] Referring now to FIG. 2A, a schematic diagram of a pyrometer 220 according to one embodiment is shown. In one embodiment, the pyrometer 220 can include a pair of photodiodes 223 A and 223 B . The photodiodes 223 can be suitable for converting an optical signal into an electrical signal. For example, the photodiodes 223 A and 223 B can be configured to detect infrared electromagnetic radiation emitted by a thermal body, such as a semiconductor wafer.

[0016] In one embodiment, the photodiode 223 can be coupled to a measurement system. The measurement system can include a signal scaling module 226 and an ADC 227. In the illustrated embodiment, a single scaling module 226 and ADC 227 are shown. However, in other embodiments, each photodiode 223 can be coupled to a different signal scaling module 226 and ADC 227. In one embodiment, the signal scaling module 226 can be responsible for changing (e.g., amplifying) the signal provided by the photodiode 223 before the signal reaches the ADC 227. The ADC 227 can have any suitable ADC architecture, sampling rate, dynamic range, etc.

[0017] The pyrometer 220 can further include a calibration module 228. That is, the calibration module 228 can be integrated into the pyrometer 220 itself. Generally, the calibration module 228 uses the switch 224 A or 224 B by engaging it with a calibrated current source 225. The calibrated current source 225 can include a battery or the like. The calibrated current source 225 can then be used to construct a transfer function for each operating mode of the ADC 227. For example, each mode can include an integration time for the ADC 227 and a range for the signal scaling module 226. The transfer function can include two coefficients that are used to calculate an accurate temperature report. After calibration is complete, the switches 224 A and 224 B can be switched off from the calibrated current source 225 to return the input to the signals from the photodiodes 223 A and 223 B A more detailed description of the calibration system and the method for calibrating the pyrometer 220 will be described in more detail below.

[0018] In one embodiment, the pyrometer 220 may further include a selector 229. The selector 229 may be used to select a mode used to operate the ADC 227 and the signal scaling module 226. The selector 229 may select a mode based on different parameters. In one embodiment, the selector 229 is used for the first photodiode 223 A To provide the best performance for the ADC227 coupled to, or for the second photodiode 223 B A mode can be selected to provide the best performance for the coupled ADC227. In other embodiments, the selector 229 can select the first photodiode 223 A or a second photodiode 223 B Either of the following can be used. For example, whichever of the two photodiodes 223 has the highest or lowest signal strength can be used to select the desired mode.

[0019] In one embodiment, the pyrometer 220 may also include a calculator module 230. The calculator module 230 may use a transfer function for a given mode to generate an accurate report of the temperature observed by the pyrometer. In one embodiment, the transfer function is stored in a lookup table or memory (not shown) on the pyrometer 220. The transfer function may include a first coefficient (k) multiplied by the reading of the ADC 227 and a second coefficient (b) which is an offset value. The calculator module 230 may take the form I = k * ADC + b.

[0020] In some embodiments, the dark current value may also be stored in a lookup table or memory. The dark current may be subtracted from the calculated value to determine an accurate temperature value. In such embodiments, the calculator module 230 may take the form I = k*ADC + b - dark current. The dark current may be the value of the current flowing through the pyrometer 220 when the pyrometer 220 is in a dark environment. That is, in the case of a photodiode 223 tuned to detect infrared radiation, the photodiode 223 may be placed in an enclosure that is opaque to infrared radiation in order to measure the dark current. If the dark current is not subtracted, noise in the system may result in inaccurate temperature readings. The dark current may be mode-independent.

[0021] Next, referring to Figure 2B, a schematic diagram of a pyrometer 220 according to an additional embodiment is shown. The pyrometer 220 in Figure 2B may be substantially the same as the pyrometer 220 in Figure 2A, except for the number of photodiodes 223. A and 223 B Instead, there is only a single photodiode 223. An example of one photodiode 223, as well as two photodiodes 223. A and 223 B While the example shown is given, please understand that the pyrometer 220 may have any number of photodiodes 223 (for example, one or more photodiodes).

[0022] In the illustrated embodiment with a single photodiode 223, the selector 229 is not very complex. Instead of requiring a selection between two photodiodes 223, the selector 229 only needs to consider a single photodiode 223. Therefore, the mode selected by the selector 229 will optimize the performance for the single photodiode 223. Furthermore, since only a single photodiode 223 is provided, the connections between components are reduced as only a single channel is required.

[0023] Referring next to Figure 3, a process flow diagram of process 340 for calibrating a pyrometer according to one embodiment is shown. In one embodiment, the pyrometer being calibrated may include one or more photodiodes, such as the examples described in more detail above. Furthermore, calibration hardware, firmware, and / or software may be integrated into the pyrometer.

[0024] In one embodiment, process 340 may begin with operation 341, which includes connecting a calibration module to a calibrated current source. In one embodiment, the input line to the calibration module may be implemented by a switch. During the calibration operation, the switch may be positioned so that the input line is electrically coupled to the calibrated current source. In one embodiment, the calibrated current source is a current source having a known current. In one embodiment, the calibrated current source may be implemented using a battery integrated with the pyrometer. However, in other embodiments, the current source may be located outside the pyrometer. In one embodiment, the calibrated current source may provide a single current value. In other embodiments, the calibrated current source may be configured to provide multiple different current values. The use of a calibrated current source allows the calibration module to know how much the input current should be so that effects (such as noise) originating from the pyrometer circuit can be determined.

[0025] In one embodiment, process 340 may continue with operation 342, which includes finding transfer functions for multiple modes. In one embodiment, each mode may correspond to a pairing of integral time for the ADC and range for the signal scaling module. Multiple modes are used to improve the sensitivity of the ADC throughout the ADC's dynamic range. A selector will choose a particular mode depending on where the signal is within the ADC's dynamic range. In one embodiment, the transfer function for each mode may include a pair of coefficients. A first coefficient (k) will be multiplied by the ADC output, and a second coefficient (b) is an offset value.

[0026] In one embodiment, the transfer function can be calculated from any known processing operation. For example, the transfer function may be a pair of coefficients (k and b) such that the measured current is equal to the current of the calibrated current source. In this way, the influence of circuits, modules, and components on the output can be considered to provide a more accurate temperature measurement. Furthermore, it should be understood that circuits, modules, and components may have different effects depending on the amount of current supplied through the system. Therefore, different modes are used to calibrate the ADC over its entire dynamic range.

[0027] In one embodiment, process 340 may continue with operation 343, which includes storing the transfer function in a lookup table. In one embodiment, the transfer function may be stored in a lookup table provided in memory accessible to the pyrometer. For example, a memory die or other memory architecture may be integrated into the pyrometer. That is, the source of memory may be provided on a board housing the electronics for the pyrometer.

[0028] Referring next to Figure 4, a process flow diagram of a process 450 for measuring temperature by a pyrometer according to one embodiment is shown. In one embodiment, the pyrometer may be similar to any of the pyrometers described in more detail herein. More specifically, the pyrometer may be a pyrometer that includes an integrated calibration module to provide improved calibration of the pyrometer.

[0029] In one embodiment, process 450 may begin with operation 451, which includes receiving an optical signal by an ADC. In one embodiment, the optical signal may first be processed by a photodiode. The photodiode may convert the optical signal (e.g., an infrared signal) into an electrical signal. The electrical signal may then be passed through a signal scaling module before reaching the ADC. In one embodiment, the pyrometer includes a single photodiode. In other embodiments, the pyrometer may include two or more photodiodes. In such embodiments, each photodiode may report the electrical signal to a different channel of the ADC, or to two different ADCs.

[0030] In one embodiment, process 450 may continue with operation 452, which includes selecting a mode based on the location of the electrical signal within the dynamic range of the ADC. That is, the dynamic range of the ADC may be segmented into multiple separate sections. Segmentation of the dynamic range allows different parameters to be applied to the signal to optimize the accuracy and sensitivity of the ADC. In one embodiment, the mode may include an integration time for the ADC and a range for the signal scaling module.

[0031] In one embodiment, the mode may be selected based on the output of the channel of the ADC coupled to the first photodiode, or based on the output of the channel of the ADC coupled to the second photodiode. In other embodiments, the mode may be selected based on which ADC channel is the highest or lowest. While separate channels of a single ADC are contemplated herein, it should be understood that similar embodiments may be used when each photodiode has a separate ADC.

[0032] In one embodiment, process 450 may continue with operation 453, which includes setting the integration time and range for the mode. In one embodiment, the integration time may be applied to the ADC, and the range may be applied to the signal scaling module. Values ​​for the integration time and range may be stored in memory integrated into the pyrometer.

[0033] In one embodiment, process 450 may continue with operation 454, which includes calculating the current based on a transfer function for the mode. The transfer function for the mode may be stored in a lookup table. The transfer function may be determined using a calibration process, such as the process described in more detail above. The transfer function may include a pair of coefficients (k and b). In one embodiment, the above calculation may include using those coefficients to calculate the current. For example, the formula may be: I = k * ADC + b.

[0034] In some embodiments, the above calculation may further include adjusting the dark current in the system. In such embodiments, the formula may be: I = k*ADC + b - dark current. The dark current value may also be stored in a lookup table. The dark current may be determined during the calibration of the pyrometer, during the assembly of the pyrometer, or at any other time.

[0035] Next, referring to Figure 5, a plan view of a pyrometer 520 according to one embodiment is shown. In one embodiment, the pyrometer 520 may include a board 519. The board 519 may be a printed circuit board or the like. In one embodiment, multiple modules and / or components may be coupled to the board 519.

[0036] In one embodiment, a photodiode 523 may be provided on the board 519. The photodiode 523 may include optics to detect an optical signal (e.g., an infrared electromagnetic radiation signal) from the thermal body. In the illustrated embodiment, a single photodiode 523 is shown. However, it should be understood that the embodiment may include two or more photodiodes 523. The photodiode 523 converts the optical signal into an electrical signal.

[0037] In one embodiment, the pyrometer 520 may further comprise a signal scaling module 526 and an ADC 527. The signal scaling module 526 and ADC 527 may be used to convert an electrical analog signal into a digital signal which can be used to calculate the current obtained by the photodiode 523. The signal scaling module 526 and ADC 527 may include multiple channels to accommodate multiple photodiodes 523.

[0038] In one embodiment, the pyrometer 520 may include a mode selector module 529. The mode selector module 529 may be used to select an appropriate mode for accurately measuring the signal from the photodiode 523. The mode may include an integral time for the ADC 527 and a range for the signal scaling module 526. The integral time for the ADC 527 and the range for the scaling module 526 may be stored in a lookup table accessible to the mode selector 529. For example, the lookup table may be provided in memory 531.

[0039] In one embodiment, the pyrometer 520 may further comprise a calibration module 528. The calibration module 528 is used to calibrate the signal obtained from the photodiode 523. The calibration module 528 may generate a plurality of transfer functions. Each transfer function may be associated with one of the modes described above. The transfer functions may include pairs of coefficients (k and b). These coefficients may be used by the calculator module 530 to calculate a calibrated value of the current using formulas, such as those described in more detail above.

[0040] In one embodiment, the calibration module 528 may be configured to be selectively coupled to a calibration current source 525. The calibration current source 525 may provide a known value of current to assist in the calibration of the pyrometer 520. Specifically, the calibration module 528 has a known current from the calibration current source 525 and receives an input current from the system passing through the circuit of the pyrometer 520. The difference between the calibration current and the input current may then be determined, and the calibration module 528 generates coefficients for a transfer function to convert the input current to a value equal to the calibration current. In one embodiment, the calibration current source 525 provides a single current. In other embodiments, the calibration current source 525 may provide multiple different current values.

[0041] Next, referring to Figure 6, a process flow diagram of process 660 for assembling a pyrometer according to one embodiment is shown.

[0042] In one embodiment, process 660 may begin with operation 661, which includes assembling the board without photodiodes. The board may include components or modules such as a signal scaling module, an ADC, a calibration module, a calibration current source, a selector module, and a calculator module.

[0043] In one embodiment, process 660 may continue with operation 662, which includes calibrating the board. Calibration may be similar to any of the calibration processes described in more detail above. For example, a calibration current source may supply a calibration module with an input current of known value that passes through the electronics. The calibration module detects the level of the current and compares it to a known calibration current level. The calibration module then produces a transfer function with coefficients (k and b) used to convert the measured current to a known calibration current. The transfer function is then stored in a lookup table for use during the operation of the pyrometer.

[0044] In one embodiment, process 660 may continue with operation 663, which includes determining the dark current for the board. The dark current may be measured by supplying a transient photodiode to the board and measuring the resulting current supplied through the system when the pyrometer is placed in a dark enclosure (e.g., opaque to infrared radiation). The value of the dark current may be stored in the pyrometer's lookup table. After the dark current has been determined, the transient photodiode may be removed. In one embodiment, the dark current is mode-independent.

[0045] In one embodiment, process 660 may continue with operation 664, which includes assembling a photodiode onto a board. The photodiode may be mounted on the board at a physical location different from where the rest of the board is assembled. For example, a partially assembled board may be assembled in a first facility, and the photodiode may be assembled onto the board in a second facility.

[0046] In one embodiment, process 660 may continue with operation 665, which includes calibrating the board a second time. In one embodiment, the second calibration may be used to inspect the electronics and ensure that everything is functioning correctly. The second calibration process may not use a calibration module in some embodiments.

[0047] Referring now to Figure 7, a cross-sectional view of a processing chamber 770 according to one embodiment is shown. In one embodiment, the chamber 770 may comprise any type of semiconductor manufacturing chamber that may require precise substrate temperature control. The illustrated embodiment shows a chamber 770 without plasma capabilities. However, it should be understood that the chamber 770 may also be capable of using plasma to implement various processing regimes.

[0048] In one embodiment, the chamber 770 may comprise a chamber body 710. The chamber body 710 may include any suitable material, such as stainless steel. In one embodiment, a coating (not shown) may be provided on the inner surface of the chamber body 710. For example, the coating may be a chamber seasoning or protective layer. In one embodiment, gas 711 may enter the chamber 770 through a first portion of the chamber body 710, and gas 712 may exit the tool through a second portion of the chamber body 710. While gases 711 and 712 are shown entering and exiting the chamber body 710, it should be understood that the gases may enter or exit the chamber through any portion of the chamber 770, depending on the type of chamber 770 being used.

[0049] In one embodiment, a substrate support 705 and a susceptor 707 are provided in a chamber. The substrate support 705 and susceptor 707 are configured to hold and / or fix a substrate 709. For example, the substrate 709 may be a semiconductor substrate, such as a silicon wafer. The substrate 709 may have any preferred form factor. For example, the diameter of the substrate 709 may be 300 mm, 450 mm, or any standard wafer form factor. Furthermore, other substrates 709 may be used in the chamber 770. For example, in some embodiments, glass substrates, ceramic substrates, etc., may also be used. In one embodiment, the substrate support 705 and susceptor 707 may be configured to rotate. This rotation allows for improved temperature uniformity across the substrate 709.

[0050] The susceptor 707 may include any type of chucking architecture for securing the substrate 709. In some embodiments, the susceptor 707 may include an electrostatic chucking (ESC) architecture. In such embodiments, the substrate 709 is secured to the susceptor 707 by electrostatic force. Other embodiments may include a vacuum chucking architecture for the susceptor 707. In one embodiment, the susceptor 707 and the substrate support 705 may include a quartz material or another material that is at least substantially transparent to infrared radiation. Thus, the temperature of the back surface of the substrate 709 can be obtained by the pyrometer 706.

[0051] In one embodiment, the chamber 770 may include a lid 715. The lid 715 is sometimes referred to as a chamber dome. Although shaped as a dome, it should be understood that the lid 715 may have any architecture (e.g., a flat surface). The lid 715 may be formed from a material that is at least substantially transparent to infrared radiation. For example, the lid 715 may include quartz.

[0052] In one embodiment, the chamber 770 may also include a bottom lid 717. The bottom lid 717 may cover the bottom surface of the chamber 770. The bottom lid 717 may include a material that is at least substantially transparent to infrared radiation. Thus, a pyrometer 706 on the bottom side of the chamber 770 may be used to measure the temperature of the bottom surface of the substrate 709. In one embodiment, the bottom lid 717 may be coupled to the substrate support 705. More specifically, the substrate support 705 may pass through the bottom lid 717. The bottom lid 717 is coupled to the substrate support 705 in a manner that allows the substrate support 705 to rotate freely.

[0053] In one embodiment, a plurality of lamps 735 may be provided outside the internal volume of the chamber 770. The internal volume of the tool may refer to the volume defined by the lid 715, the chamber body 710, and the bottom lid 717. That is, the lamps 735 are not provided within the internal volume of the chamber 770 on which the substrate processing is mounted. In one embodiment, a plurality of pyrometers 706 may be provided through the bottom lid 717. The pyrometers 706 may be concentrated on the back surface of the substrate 709. In one embodiment, the pyrometers 706 may be similar to any of the pyrometers described in more detail herein. For example, the pyrometers 706 may include an internal calibration module.

[0054] Referring now to Figure 8, a block diagram of an exemplary computer system 800 of a processing tool according to one embodiment is shown. In one embodiment, the computer system 800 is coupled to the processing tool and controls the processing in the processing tool. The computer system 800 may be connected to other machines (e.g., networked) in a local area network (LAN), intranet, extranet, or internet. The computer system 800 may operate as a server machine or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system 800 may be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), cellular telephone, web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) specifying the actions to be taken by that machine. Furthermore, although only a single machine is shown for computer system 800, the term “machine” shall also be interpreted to include any set of machines (e.g., computers) that individually or collectively execute a set (or set) of instructions to implement one or more of the methodologies described herein.

[0055] The computer system 800 may include a computer program product or software 822 having a non-temporary machine-readable medium storing instructions, which may be used to program the computer system 800 (or other electronic devices) to perform a process, according to the embodiment. The machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, machine-readable (e.g., computer-readable) medium includes machine (e.g., computer)-readable storage media (e.g., read-only memory ("ROM"), random-access memory ("RAM"), magnetic disk storage media, optical storage media, flash memory devices, etc.), machine (e.g., computer)-readable transmission media (e.g., electrical, optical, acoustic or other forms of propagating signals (e.g., infrared signals, digital signals, etc.)), etc.

[0056] In one embodiment, the computer system 800 includes a system processor 802 that communicates with each other via a bus 830, main memory 804 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), static memory 806 (e.g., flash memory, static random access memory (SRAM)), and secondary memory 818 (e.g., a data storage device).

[0057] The system processor 802 represents one or more general-purpose processing devices, such as a microsystem processor or a central processing unit. More specifically, the system processor may be a composite instruction set computing (CISC) microsystem processor, a reduced instruction set computing (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor implementing another instruction set, or a system processor implementing a combination of instruction sets. The system processor 802 may also be one or more dedicated processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal system processor (DSP), or a network system processor. The system processor 802 is configured to execute processing logic 826 for performing the operations described herein.

[0058] The computer system 800 may further include a system network interface device 808 for communicating with other devices or machines. The computer system 800 may also include a video display unit 810 (e.g., a liquid crystal display (LCD), a light-emitting diode display (LED), or a cathode ray tube (CRT)), an alphanumeric input device 812 (e.g., a keyboard), a cursor control device 814 (e.g., a mouse), and a signal generation device 816 (e.g., a speaker).

[0059] The secondary memory 818 may include a machine-accessible storage medium 832 (or more specifically, a computer-readable storage medium) storing one or more sets of instructions (e.g., software 822) that embody any one or more of the methodologies or functions described herein. The software 822 may also reside entirely or at least partially in the main memory 804 and / or the system processor 802 while the computer system 800 is executing the software 822, the main memory 804 and the system processor 802 also constitute the machine-readable storage medium. The software 822 may further be transmitted or received over the network 820 via a system network interface device 808. In one embodiment, the network interface device 808 may operate using RF coupling, optical coupling, acoustic coupling, or inductive coupling.

[0060] Although the machine-accessible storage medium 832 is shown to be a single medium in exemplary embodiments, the term “machine-readable storage medium” should be interpreted to include a single or multiple mediums (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. The term “machine-readable storage medium” should also be interpreted to include any medium capable of storing or encoding a set of instructions for machine execution, causing a machine to implement one or more methodologies. The term “machine-readable storage medium” should therefore be interpreted to include, but are not limited to, solid memory and optical and magnetic media.

[0061] The above specification describes specific exemplary embodiments. It will be apparent that various modifications can be made thereto without departing from the scope of the following claims. Therefore, this specification and the drawings should be considered illustrative rather than restrictive.

Claims

1. A method for calibrating a tool for converting photonic signals into electrical signals, Connecting the calibration module to a calibrated current source, The calibration module allows for finding the transfer function for multiple modes, The transfer function is stored in a lookup table. Methods that include...

2. The method according to claim 1, wherein each of the multiple modes includes integral time and range.

3. The method according to claim 2, wherein the integral time is supplied to the ADC in the tool, and the range is supplied to the signal scaling module in the tool.

4. The method according to claim 1, wherein the transfer function includes a first coefficient and a second coefficient, the first coefficient being multiplied by an ADC value and the second coefficient being an offset value.

5. The method according to claim 1, wherein the calibration further comprises finding the dark current of the tool.

6. The method according to claim 1, wherein the tool is a pyrometer or emitter.

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